Department of Vascular Medicine, University Medical Center Utrecht, Academic Hospital Utrecht, 3584 CX Utrecht, The Netherlands
![]() |
ABSTRACT |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
Renal function is highly dependent on endothelium-derived nitric oxide (NO). Several renal disorders have been linked to impaired NO bioavailability. The enzyme that is responsible for the synthesis of NO within the renal endothelium is endothelial NO synthase (eNOS). eNOS-mediated NO generation is a highly regulated cellular event, which is induced by calcium-mobilizing agonists and fluid shear stress. eNOS activity is regulated at the transcriptional level but also by a variety of modifications, such as acylation and phosphorylation, by its cellular localization, and by protein-protein interactions. The present review focuses on the complex regulation of eNOS within the endothelial cell.
renal physiology; cardiovascular physiology; cell biology
![]() |
INTRODUCTION |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
ENDOTHELIUM-DERIVED NITRIC oxide (NO) has important effects on the renal vasculature. It modulates the constrictor actions on the afferent arteriole (35, 74, 75). In addition to its direct effects on glomerular microvascular tone, NO decreases the sensitivity of the tubuloglomerular feedback system (14). NO is also a crucial modulator of renal medullary blood flow, allowing pressure natriuresis (101, 135, 137). In addition, renal medullary oxygenation appears to be critically dependent on an intact vascular NO system (15). Finally, endothelium-derived NO prevents leukocyte infiltration of the vessel wall and thrombus formation in the renal vasculature (161). Related to these NO-dependent processes, a dysfunctional renal vascular NO system has been associated with (salt-sensitive) hypertension (9, 37), ischemic injury of the kidney (78, 82, 100), and tubulointerstitial renal disease (161, 162). It is of interest that these vascular effects of NO may not only be generated through the endothelial nitric oxide synthase (eNOS), which is the classic "vasculoprotective" NOS isoform but may also involve vascular expression of the neuronal (nNOS) and inducible isoforms (iNOS) of the enzyme (2, 81, 102). Nevertheless, functional studies suggest that the eNOS isoform is the key enzyme in these processes (102). New functions of eNOS in the kidney have recently been described as well. For example, the NO-mediated inhibition of chloride in the medullary thick ascending limb appears to depend on the endothelial isoform of NOS (124). The present review therefore focuses on the regulation of eNOS function. In particular, the structure-function relationships of the enzyme and its cellular regulation are reviewed.
![]() |
FUNCTION AND ACTIVITY OF eNOS: NO VS. SUPEROXIDE |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
The free radical NO is generated exclusively by the enzyme NOS.
Three isoforms of NOS have been identified, which are highly homologous
in their primary structure (Fig. 1). Two
isoforms are constitutively expressed, although their expression may be
modulated: nNOS (or NOS1) is expressed in neurons, and eNOS (or NOS3)
is expressed in endothelial cells, cardiac myocytes, and blood
platelets. The expression of iNOS (or NOS2) is not constitutive but is
induced by various cytokines. NO is synthesized from
L-arginine through a five-electron oxidation step via the
formation of the intermediate NG-hydroxy-L-arginine (119,
171). The substrates for NOS-mediated NO production are the
amino acid arginine, molecular oxygen, and NADPH. Cofactors that are
required for NO generation are tetrahydrobiopterin (BH4), flavin
adenine dinucleotide, and flavin mononucleotide. Furthermore, the
enzyme contains binding sites for heme and calmodulin, both being
essential for enzyme activity. After binding of calcium-loaded calmodulin to eNOS between the COOH-terminal reductase and
NH2-terminal oxygenase domain of eNOS, electrons are
donated by NADPH at the reductase domain, which are subsequently
shuttled through the calmodulin-binding domain toward the
heme-containing eNOS oxygenase domain, which may result in the
formation of the enzyme products citrulline and NO (1).
eNOS also contains a motif involved in the binding of zinc
(130). Each eNOS dimer contains one zinc ion, which plays
a role in stabilization of the dimeric molecule.
|
Under certain conditions, NOS may generate superoxide instead of NO, a
process called NOS uncoupling (i.e., uncoupling of NADPH oxidation and
NO synthesis) (126). Superoxide generation by eNOS is
mediated via the heme group of its oxygenase domain (147)
and is dependent on the presence of its substrate, arginine, and its
cofactor, BH4 (155, 165). When there is an abundance of
both factors, eNOS produces NO. When the concentration of one of these
factors is relatively low, eNOS generates superoxide. For instance,
inhibition of BH4 synthesis in endothelial cells by
2,4-diamino-6-hydroxypyrimidine, an inhibitor of the rate-limiting enzyme in BH4 synthesis, GTP cyclohydrolase I, results in a reduction of NO synthesis, whereas eNOS-mediated superoxide synthesis is increased. This effect can be antagonized by the so-called BH4 salvage
pathway, when endothelial cells are incubated with sepiapterin, which
results in an increase in cellular BH4 levels, independent of GTP
cyclohydrolase I (73). Similar findings have been reported for nNOS. The nNOS heme domain also produces superoxide when
concentrations of arginine and/or BH4 are low (125, 154).
In contrast, iNOS may also generate superoxide via its reductase domain
(167). NOS uncoupling has also been reported in vivo.
NOS-mediated superoxide generation has been suggested to occur in renal
proximal tubules that were exposed to lipopolysaccharides
(153), in renal arteries exposed to oxidized low-density
lipoproteins (LDL) (129), in reperfusion injury after
ischemia (68), in pulmonary hypertension (111), and in hypercholesterolemia (31, 148).
These data indicate that NOS activity is regulated by the abundance of
its substrate and cofactor, although many more regulatory mechanisms
exist in the cell, all of which contribute to the enzyme activity of
eNOS (Fig. 2).
|
![]() |
TRANSCRIPTIONAL REGULATION OF eNOS |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
Although the term "inducible" has been restricted to iNOS,
eNOS expression is also regulated by a variety of stimuli. First, its
basal expression is largely tissue dependent (151). eNOS is predominantly expressed in endothelial cells of large- and medium-sized blood vessels. In addition, there are numerous factors that affect the basal expression levels. For instance, fluid flow across the endothelium, also referred to as shear stress, upregulates eNOS expression (114, 115). Six shear stress-responsive
elements have indeed been identified in the eNOS promotor sequence on
cloning of the eNOS cDNA and identification of the promotor region
(114, 141). Besides shear stress-responsive elements, the
eNOS promotor also contains other putative cis-elements,
including Sp1 and GATA motifs, a sterol regulatory element,
estrogen-responsive elements, a nuclear factor-1 element, a
cAMP-responsive element, and activator protein-1 (AP-1) and -2 (AP-2)
binding sites (99, 134). Sp1 has been shown to be involved
in lysophosphatidylcholine (lysoPC)-induced eNOS upregulation
(25), whereas AP-1 activation mediates increases in eNOS
expression in the presence of immunosuppresive drugs such as
cyclosporin A (112). eNOS expression is also upregulated
by cyclic strain (7), agents that inhibit protein kinase C
(PKC) (116), enhanced proliferative state
(6), hydrogen peroxide (39), estrogen
(150), vascular endothelial growth factor (VEGF) (13, 83), insulin (84), basic fibroblast
growth factor (175), epidermal growth factor
(175), transforming growth factor- (TGF-
) (72), and low concentrations of oxidized LDL or its major
atherogenic phospholipid lysoPC (67, 172). An increased
eNOS expression by lysoPC and moderate amounts of oxidized LDL may
implicate an endothelial antiatherosclerotic defense mechanism at the
early stages of lesion formation.
Several factors that are known to lower eNOS expression include tumor
necrosis factor- (TNF-
) (114), erythropoietin
(163), hypoxia (105), and high concentrations
of oxidized LDL (88). In line with these regulatory
mechanisms, renal eNOS expression is increased along with increases in
cyclic strain as can be found in, e.g., hypertension secondary to lead
or angiotensin II infusion (24, 156), whereas such an
increase could not be found in erythropoietin-induced hypertension
(113). Another determinant of eNOS expression is NO
itself. NO has been shown to be involved in a negative-feedback regulatory mechanism and decreases eNOS expression via a cGMP-mediated process (157). In agreement, the decrease in glomerular
filtration rate after administration of lipopolysaccharides could be
attributable to inhibition of eNOS function, most likely by NO
autoinhibition via activation of iNOS (139).
There is a marked discrepancy among amounts of eNOS mRNA, eNOS protein,
and eNOS activity, demonstrating complex regulatory mechanisms at the
posttranscriptional and posttranslational level. An important feature
here that concerns posttranscriptional/posttranslational regulation is
the stability (i.e., half-life) of the eNOS mRNA (12).
mRNA levels represent the balance between gene transcription and mRNA
degradation. The kinetics of mRNA degradation is dependent in part on
nucleotide sequence motifs, which are usually located in the 3'
untranslated region of the gene. Possible interactions of specific
proteins to these sequences may render the mRNA more or less
susceptible to endonucleolytic cleavage. Two motifs often implicated in
mRNA destabilization are present at the 3' end of the eNOS mRNA
(99). In accordance, some stimuli affect eNOS mRNA
stability. TNF- destabilizes eNOS mRNA, which is suggested to be
mediated by the increased binding of regulatory cytosolic proteins to
the 3' untranslated region of the eNOS mRNA (3). Other
stimuli that have been reported to decrease eNOS mRNA stability include
lipopolysaccharides (endotoxins) (97), hypoxia
(105), and oxidized LDL (91). Such mechanisms
could also be involved in decreased eNOS expression in inflammatory
models of renal injury such as necrotizing crescentic
glomerulonephritis (65). On the other hand, certain
conditions of shear stress upregulate eNOS mRNA levels through
posttranscriptional events (176). VEGF- as well as
hydrogen peroxide-induced eNOS upregulation are also dependent on an
enhanced stability of eNOS mRNA (13, 39). In conclusion, eNOS expression is affected by various stimuli, which modify eNOS regulation at the mRNA level by inducing changes in transcription kinetics and stability of the eNOS mRNA.
![]() |
COTRANSLATIONAL MODIFICATION OF eNOS: MYRISTOYLATION |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
In contrast to the other NOS isoforms, eNOS contains a myristoyl group that is covalently attached to the glycine residue at its NH2 terminus. The turnover of the myristoyl group is as slow as that of eNOS itself, demonstrating the irreversibility of myristoylation (92). Myristoylation renders eNOS membrane bound, whereas iNOS and nNOS are predominantly, if not exclusively, cytoplasmic. The presence of eNOS at the membrane (especially at the plasma membrane) may serve an important purpose. It may bring eNOS in close proximity to factors that are required for its proper function, such as arginine, calcium, and cofactor BH4. It is of particular interest that arginine and calcium channels have indeed been identified in caveolae at the plasma membrane (51, 104). Studies in which the myristoylation site of eNOS was mutated have demonstrated that the myristoyl moiety is an absolute requirement for the membrane localization and activity of eNOS (136). Without this modification, eNOS is almost completely cytosolic and lacks palmitoyl moieties (94, 133). Most likely, myristoylation targets eNOS to the Golgi complex, where it is palmitoylated (140). Nevertheless, the NO-generating activity of the myristoyl-deficient enzyme in vitro is not impaired (44).
![]() |
eNOS REGULATION AT THE POSTTRANSLATIONAL LEVEL |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
eNOS Palmitoylation
Degradation of eNOS is probably neither regulated nor modified by cellular responses, because eNOS has a rather long half-life of ~20 h (92). A posttranslational modification that does modify eNOS activity is palmitoylation. eNOS is palmitoylated on two cysteine residues near the NH2 terminus (cysteine-15 and -26). This modification is reversible, requires eNOS myristoylation, stabilizes the association of eNOS with the membrane, and is required for a proper localization of eNOS (92). The steady-state turnover of the eNOS palmitoyl modification is 25 times faster than that of the myristoyl moiety or that of eNOS itself (92). The unique (Gly-Leu)5 repeat between the two palmitoylation sites of eNOS is required for the palmitoylation (94). Agonists such as bradykinin have been suggested to promote eNOS palmitate turnover with a concomitant release of eNOS from the plasma membrane (133). Whether the transient depalmitoylation of eNOS is required for its agonist-induced activation is unclear. eNOS depalmitoylation is suggested to be mediated by the cytosolic enzyme acyl-protein thioesterase and to be potentiated by calcium-bound calmodulin (170). However, these bradykinin-induced phenomena were contradicted by others (92). The cellular enzyme activity of eNOS in which the palmitoylation sites were mutated was markedly decreased, but to a lesser extent than for the myristoyl-deficient enzyme (143). A mutated palmitoyl-deficient enzyme displays an altered cellular distribution compared with wild-type eNOS and is hardly detectable at the plasma membrane (57, 133). The reduced amount of NO generated by the palmitoylation-deficient enzyme within the endothelial cell was not caused by alterations in its catalytic properties, because purified wild-type and palmitoyl-deficient eNOS were kinetically identical (93). Again, these findings strongly indicate that the enzymatic activity of eNOS within the endothelial cell is dependent on its intracellular distribution.eNOS Activation: Calcium vs. Tyrosine Phosphorylation
NOS differs from iNOS in that its activity is dependent on the presence of calcium and calmodulin. iNOS binds calmodulin very tightly so that calmodulin forms a constitutive subunit. eNOS activity is regulated by changes in the cytosolic calcium concentration and is therefore activated by hormones that induce a rise in intracellular calcium levels, such as bradykinin (62), estradiol (59), serotonin (17), VEGF (120), and histamine (79). Calmodulin binds the calcium, and the calcium-calmodulin complex interacts with eNOS, resulting in increased enzyme activity (see eNOS Localization in Caveolae).On the other hand, eNOS activation by hemodynamic shear stress as well as isometric vessel contraction is independent of calcium (8, 49). The exact mechanism behind this mechanochemical transduction process is not completely understood. Shear stress-induced eNOS activation is regulated by a potassium channel, which might act as a mechanochemical transducer within the plasma membrane of the endothelial cell (27, 118), whereas it is not involved in eNOS activation by calcium-mobilizing agents (69). Other cell components that play a role in shear stress-induced eNOS activation include caveolae and the cytoskeleton (70, 132). The endothelial cytoskeletal network usually maintains the shape of the endothelial cell, which is essential for the relative impermeability of the endothelial lining of the vessel wall. An alteration in fluid flow across the endothelium results in a change in the tension of the endothelial cytoskeleton and in the transmission of this signal throughout the cell, which immediately modulates eNOS activity. Accordingly, disruption of the cytoskeleton attenuates flow-induced eNOS activity, although it does not affect agonist-induced calcium-dependent NO generation (70). Interestingly, NO is important for stability of the endothelial cytoskeleton and therefore has a role in the relative impermeability of the endothelium (85, 96). In contrast, under certain conditions (e.g., hypoxia) and dependent on the vascular bed, endothelial permeability is enhanced due to VEGF-induced increases in NO levels (47). Furthermore, shear stress-induced eNOS activation is abrogated in the presence of tyrosine kinase inhibitors, suggesting that tyrosine phosphorylation is involved (8, 28). The tyrosine kinase involved in this process might be the VEGF receptor Flk-1, because this receptor is phosphorylated and associated with the adaptor protein Shc on application of shear stress (21). Shear stress, but also calcium-mobilizing agents, activate protein tyrosine kinases and result in enhanced tyrosine phosphorylation of specific proteins of 42 and 44 [mitogen-activated protein (MAP) kinases] and proteins of 88, 90, 103, and 114 kDa (8, 22). Moreover, estradiol- and VEGF-induced increases in eNOS activity are attenuated by tyrosine kinase inhibitors (22, 120), suggesting that tyrosine phosphorylation may be required for eNOS activation by both shear stress and calcium-mobilizing agents.
The protein tyrosine phosphatase inhibitor phenylarsine oxide has been shown to activate eNOS in the presence and absence of extracellular calcium and the calmodulin inhibitor calmidazolium, which is in accordance with the other indications that suggest that tyrosine phosphorylation is essential for calcium-independent eNOS activation (48). The phenylarsine oxide-induced effect is inhibited by the protein tyrosine kinase inhibitor erbstatin. Also, ceramide enhances eNOS activity in a calcium-independent manner (71). Whether this is accompanied by an increase in eNOS phosphorylation or is dependent on tyrosine phosphorylation of other proteins is not known. Recently, there have been some indications that eNOS might be phosphorylated on tyrosine residues, although this is suggested to be dependent on the amount of cell passages, indicating that the intracellular mechanisms that regulate tyrosine phosphorylation of eNOS are rapidly lost when cells are cultured (48, 55). This may have been the reason why many others have failed to detect tyrosine phosphorylation of eNOS (28, 38, 159, 160).
eNOS Serine Phosphorylation
eNOS is phosphorylated on serine residues on exposure of endothelial cells to shear stress as well as to calcium-mobilizing agents (28, 108). In vitro, eNOS can be phosphorylated by PKC and cAMP-dependent kinase [protein kinase A (PKA)] (23, 66). In addition, PKC-activating phorbol esters induce eNOS phosphorylation in intact cells, which is accompanied by a decrease in eNOS activity. This decrease is prevented by PKC inhibitors, suggesting that eNOS activity may be regulated by PKC-mediated eNOS phosphorylation in vivo. PKA mediates phosphorylation at threonine-495 and serine-1177 of human eNOS in vitro in a calcium- and calmodulin-independent manner, resulting in eNOS activation (109). Furthermore, there have been some indications suggesting that PKA might be involved in eNOS activation in vivo (152).Recently, it was shown that the serine/threonine kinase Akt (also known as protein kinase B) phosphorylates eNOS in vitro as well as in vivo, thereby activating the enzyme (52, 53). Akt-mediated eNOS phosphorylation was suggested to play a role in both calcium-dependent and -independent eNOS activation pathways. Both shear stress and VEGF induce phosphorylation and activation of Akt (38). LY-294002 and wortmannin, inhibitors of phosphatidylinositol 3-kinase, the upstream activator of Akt, reduce shear stress-, VEGF-, and insulin-induced phosphorylation and activation of eNOS (38, 53, 174). In accordance, the use of activation-deficient Akt has demonstrated that Akt is required for VEGF- and insulin-mediated eNOS activation (52, 173). The site of phosphorylation by Akt is serine-1177 in human eNOS (52). Shear stress-induced Akt activation is unaffected by the removal of calcium or by the calmodulin antagonist calmidazolium, implying that Akt-mediated eNOS activation in response to shear stress requires only trace amounts of calcium (in a similar way to iNOS) (38). This has been confirmed by Sessa and co-workers (103), whose studies implicated that Akt-mediated eNOS phosphorylation reduces the dissociation of calmodulin from activated eNOS. Shear stress-induced serine phosphorylation of eNOS was shown to be inhibited by tyrosine kinase inhibitors, indicating that tyrosine phosphorylation of a regulatory protein, which is activated upstream of Akt, precedes Akt-mediated eNOS phosphorylation (28).
Bradykinin also induces serine phosphorylation of eNOS, which is maximal after 5 min and is prolonged for 20 min. The serine-phosphorylated enzyme is primarily cytosolic. This phosphorylation event appears to be calcium dependent, because it is inhibited by calmodulin antagonists and by removal of extracellular calcium (108, 109). Whether bradykinin-induced serine phosphorylation of eNOS is mediated by Akt and whether this is required for eNOS activation remain to be determined. Given the fact that eNOS-mediated NO generation occurs faster than bradykinin-induced serine phosphorylation of eNOS, it is likely that this phosphorylation event is involved in the downregulation of eNOS activity. Accordingly, incubation of endothelial cells with NO donors induces serine phosphorylation of eNOS, while inhibiting its activity (19, 108). This suggests that eNOS-generated NO may induce phosphorylation of eNOS in vivo and therefore may act as a negative feedback mechanism for eNOS activity. If this is the case, PKC might be the kinase involved in this inhibitory phosphorylation event, because PKC-mediated eNOS phosphorylation is known to inhibit eNOS activity (66). Furthermore, the involvement of PKC in eNOS inactivation is suggested by the fact that G protein-coupled receptors, including the receptors for bradykinin, acetylcholine, serotonin, and histamine activate phospholipase C, an upstream activator of PKC (16, 41).
Finally, other kinases could be involved as well in the regulation of eNOS activity, perhaps dependent on the agonist. For instance, studies in which the MAP kinase kinase inhibitor PD-98059 was used have suggested that members of the MAP kinase family play a role in estradiol-induced eNOS activation (22). Whether these kinases are actually able to phosphorylate eNOS itself has not been examined.
In summary, serine phosphorylation of eNOS is essential for the cellular regulation of eNOS function. It might either increase or decrease its activity, depending on the kinase and the serine residue involved. In particular, the serine/threonine kinase Akt has been shown to regulate eNOS activity in vitro as well as in vivo.
eNOS Localization in Caveolae
Studies from many research groups have indicated that the localization of eNOS within the cell determines its activity. One particular site in the cell that apparently is of importance to eNOS function is the caveolus. Caveolae are specialized invaginations of the plasma membrane and are present in most cell types, with the highest number being present in endothelial cells, adipocytes, fibroblasts, and smooth muscle cells. The main components of caveolae are cholesterol, glycosphingolipids, and some structural proteins, such as caveolin, whereas phospholipids are practically absent (121, 144). This membrane domain harbors many signal transduction pathways, and evidence is accumulating that signal transduction pathways ascending from various stimuli from outside of the cell converge at this specific spot (4, 95). eNOS was reported to be present in caveolae but not in other parts of the plasma membrane (143). However, it must be taken into account that the experimental procedures used for the isolation of caveolae might influence the experimental findings. For instance, detergent-based caveolae isolation procedures have not always allowed eNOS coisolation, although other caveolae isolation methods by the same researchers did show that eNOS was localized within caveolae (143). Similar findings have been described for the epidermal growth factor receptor (110, 164) and for the insulin receptor (64). Unfortunately, most of these studies fail to show by immunoelectron microscopic analysis of intact cells or of isolated caveolae that these particular proteins do reside in caveolae. In addition, the results of the biochemical experiments are difficult to interpret, because the presence of alternative detergent-insoluble membrane domains that are not homologous to caveolae has been demonstrated (50, 61). Thus, although present in caveolae, the presence of eNOS in other plasma membrane domains cannot be excluded.The localization of eNOS within caveolae renders the enzyme inactive.
In caveolae, eNOS activity is inhibited by caveolin-1 (77). Caveolin-1 is not exclusively located in caveolae
but is also resident in the Golgi complex and is known to bind to the
caveolae-enriched lipids cholesterol and glycosphingolipids (26). Caveolin-1 is an intrinsic membrane protein
(although not membrane spanning) that is irreversibly palmitoylated and not only binds to itself in an oligomeric complex but also interacts with eNOS via its so-called scaffolding domain (amino acid residues 82-101) (77, 107). In addition, caveolin-1 may
contain a second eNOS-binding motif (56, 77).
Interestingly, within the endothelial cell the binding of eNOS to
caveolin-1 requires both myristoylation and palmitoylation of eNOS,
whereas in vitro the eNOS-caveolin-1 interaction is independent of both
acyl groups (56). This indicates that the acyl
modifications mediate caveolar localization rather than caveolin-1. The
interaction between eNOS and the caveolin-1 scaffolding domain strongly
reduces eNOS activity because caveolin-1 interferes with the binding of
calmodulin to eNOS when cytosolic calcium levels are low (77,
106). However, the interaction with the scaffolding domain is
not restricted to eNOS. Other signaling proteins that interact with the
caveolin-1 scaffolding domain include phosphatidylinositol 3-kinase,
c-Src, and Ha-Ras (29, 89). Inhibitory interactions have
been reported for the PDGF receptor (168), epidermal
growth factor receptor (30), nerve growth factor receptor
Trk A (10), MAP kinases (40), and G protein
-subunits (90). The sequence in human eNOS that
mediates the interaction with caveolin-1 is
350FSAAPFSGW358, which
corresponds to the scaffolding domain-binding consensus sequences
X
XXXX
and
XXXX
XX
(
represents Trp, Phe, or Tyr; X represents any amino acid) (29, 56). The
activity of eNOS in which this domain was mutated was not affected by
caveolin-1, in contrast to wild-type eNOS (56). In
accordance, an increased caveolin-1 expression results in an increased
eNOS-caveolin interaction and in reduced eNOS activity (43,
44). The scaffolding domain-binding motif is situated in the
eNOS oxygenase domain, although an interaction between caveolin-1 and
the reductase domain of eNOS may also exist (58). To which
residues of the reductase domain caveolin-1 might bind is presently unknown.
Caveolae-localized eNOS also interacts with the bradykinin receptor and with the cationic amino acid transporter CAT-1 (76, 104). CAT-1 is involved in the transfer of the NOS substrate arginine across the membrane. Receptors for estrogen (80) and VEGF (42) as well as a calcium pump (51) are also present in caveolae. The receptors for bradykinin and acetylcholine are not constitutively present in caveolae but may translocate to caveolar membranes on agonist stimulation (36, 46). This indicates that most of the components required for a proper eNOS function are concentrated within the caveolae, which may facilitate eNOS function. However, the molecular interactions among eNOS, CAT-1, and G protein-coupled receptors may need further investigation, because the techniques used in these studies imply the presence of these proteins in caveolae rather than a direct interaction among these molecules due to the detergent insolubility of caveolae. Some of these molecular interactions have now been confirmed in in vitro assays (98). Moreover, the interaction of eNOS with the bradykinin receptor blocks the electron transfer within the eNOS molecule without affecting the binding of its substrate arginine and cofactor BH4 (60).
In the presence of shear stress (131) or calcium-mobilizing agents such as bradykinin (127), acetylcholine (45), estradiol (80), and calcium ionophore (45), calcium-bound calmodulin associates with eNOS, whereas caveolin-1 is displaced. The calcium ions that are mobilized into the cytosol are reported to originate from the extracellular environment and from intracellular calcium stores (i.e., endoplasmic reticulum) (32, 62). Caveolin-1 displacement may coincide with eNOS depalmitoylation (133). As a consequence of both of these processes, eNOS is released from the plasma membrane into the cytosol (108). However, this model could not be confirmed by all research groups (92). Interestingly, Venema et al. (160) reported an increased interaction of eNOS and caveolin-1 on bradykinin incubation of endothelial cells. How eNOS is inactivated is unclear. An increase in Golgi-localized eNOS after its activation has been demonstrated (127). Again, this phenomenon could not be confirmed by others (48). Probably, the activated eNOS-calmodulin complex generates NO until intracellular calcium levels drop to the point that calmodulin dissociates and the inhibitory eNOS-caveolin complex reforms (45). This is not unlikely because the agonist-induced increases and subsequent decreases in intracellular calcium and NO show similar kinetics (18).
Because cholesterol is one of the main constituents of caveolae and since hypercholesterolemia has been associated with a change in NO production (20), several laboratories have studied the effect of endothelial cholesterol loading on eNOS activity. Endothelial cells incubated in the presence of cholesterol displayed a 50% increase in NO release in response to calcium ionophore, whereas eNOS expression was increased to the same extent (123). Caveolin expression was not significantly increased in these experiments, whereas the number of caveolae was also increased by 50%. In contrast, incubations with higher amounts of cholesterol inhibited eNOS activity (34). Incubation of endothelial cells with agents that lower the cholesterol content of caveolae such as oxidized LDL and cyclodextrin resulted in translocation of both caveolin-1 and eNOS from the caveolae and in inhibition of acetylcholine-induced eNOS activation (11). Myristoylation, palmitoylation, and phosphorylation of eNOS were not affected by cholesterol depletion, implying that these molecular modifications were not involved in the eNOS inactivation. Thus, although caveolar eNOS itself is inactive, caveolar localization of eNOS is required for its activity because conditions that inhibit the localization of eNOS in caveolae (e.g., inhibition of eNOS myristoylation and cholesterol depletion) markedly decrease eNOS activity. This implies that eNOS needs to be localized in caveolae to be able to become activated.
eNOS in the Golgi Complex
Although most studies apparently agree in that NO generation requires a functional eNOS enzyme at the plasma membrane, and in particular at the caveolae, most of the cellular eNOS is contained within the Golgi apparatus in cultured endothelial cells as well as in intact blood vessels (5, 140). The first 35-amino acid residues of eNOS, containing all three acylation sites, are required and sufficient for the targeting of eNOS to the Golgi complex (94). Whether eNOS at the Golgi is bound to caveolin-1 in a similar complex as has been described for caveolae is unknown. At present, no clear suggestion has been presented on the function of the Golgi localization of eNOS. Golgi localization might be required for eNOS repalmitoylation after activation and depalmitoylation at the plasma membrane. Palmitoyl transferases may be present in the Golgi complex. Accordingly, eNOS would recycle between the plasma membrane and the Golgi complex. In that case, eNOS probably moves from the Golgi to caveolae via vesicular transport, as has been described for caveolin-1 (86). However, data supporting this hypothesis are lacking due to the few immunoelectron microscopic studies that have been presented so far.Incubation of cerebrovascular endothelial cells with the Golgi complex-disrupting agent brefeldin A inhibited NOS activity, implying that the Golgi localization of eNOS is essential for eNOS activity, although it does not provide any evidence that Golgi-localized eNOS may be directly activated (146). Probably, Golgi disruption also indirectly affects eNOS localization at the plasma membrane, because eNOS is thought to recycle between the Golgi complex and the plasma membrane. However, it cannot be completely excluded that the Golgi might be a site of NO production. That Golgi-localized eNOS is not a "silent" pool of eNOS is evident from studies in which examination of recovery after photobleaching of fluorescent-labeled eNOS showed that the enzyme is translocating to and from the Golgi complex at high speed (145).
Interaction with the Cytoskeleton
Within the endothelial cell, eNOS has been reported to reside in a detergent Triton X-100-insoluble cell fraction under resting conditions (57). However, others have reported that eNOS translocates to a Triton X-100-insoluble cell fraction on stimulation with the calcium-mobilizing agent bradykinin (159). At the same time, bradykinin induces tyrosine phosphorylation of cellular proteins, which apparently is required for translocation of eNOS because tyrosine kinase inhibitors block the translocation. Treatment of endothelial cells with bradykinin also induces a transient increase in the amount of detergent-insoluble caveolin-1 (160). Again, the translocation could be inhibited by tyrosine kinase inhibitors.Translocation of eNOS into a detergent-insoluble cell fraction is also induced by shear stress (48). Shear stress-induced eNOS activation as well as the concomitant translocation of eNOS into detergent-insoluble membranes were dependent on the presence of tyrosine kinase inhibitors. Whether caveolin-1 also translocates to a detergent-insoluble membrane fraction after shear stress has not been determined. In addition, eNOS activation by the tyrosine phosphatase inhibitor phenylarsine oxide also coincided with a translocation of both eNOS and caveolin-1 from a detergent-soluble to a detergent-insoluble cell fraction (48, 160). This translocation was independent of calcium.
Although this detergent-insoluble cell fraction has been referred to as cytoskeleton associated (87, 166), one must not forget that caveolae are also detergent insoluble (169). In addition, other distinct microdomains have been reported that are Triton X-100 insoluble and enriched in glycosyl phosphatidylinositol-anchored proteins (138). Furthermore, depending on the experimental procedures, this translocation may also account for an interaction between caveolae and the endothelial cytoskeleton, providing a possible explanation as to why both eNOS and caveolin-1 translocate to detergent-insoluble membrane domains.
Additional Interactions
A tyrosine-phosphorylated protein of 90 kDa interacts with eNOS in cultured endothelial cells (159). The interaction is markedly enhanced within 1 min of bradykinin stimulation. The associated protein was denominated eNOS-associated protein-1 (ENAP-1). At present, it is unknown whether this protein interacts directly or indirectly with eNOS or whether ENAP-1 associates with the detergent-insoluble cell fraction to which eNOS translocates on bradykinin stimulation, as was reported by the same research group (159). Although bradykinin did induce a translocation of a substantial amount of eNOS into the detergent-insoluble cell fraction, the eNOS-ENAP-1 interaction was detected in the Triton X-100-soluble cell fraction.Another protein that has been demonstrated to interact with eNOS is the 90-kDa heat shock protein (Hsp90) (54, 142). This protein belongs to the family of heat shock proteins, which affect activity and function of other proteins by acting as molecular chaperones, thereby modulating their structure. These heat shock proteins were first identified for their role in physiological stress situations (e.g., heat), but their role in common molecular regulatory mechanisms has nowadays been beyond debate. Other signaling proteins to which Hsp90 binds include G protein subunits, MAP kinase kinase, Src, and Raf (128). Binding of Hsp90 to eNOS in response to histamine, VEGF, or shear stress increases eNOS activity by facilitating the calmodulin-induced displacement of caveolin from eNOS (63). This increase in eNOS activity is inhibited by the Hsp90 inhibitor geldanamycin (54). Given the fact that Hsp90 and ENAP-1 are similar in their molecular weight, it could very well be possible that ENAP-1 is Hsp90. Whether eNOS-associated Hsp90 is indeed tyrosine phosphorylated remains to be shown.
Studies using purified eNOS and phospholipid vesicles have shown that eNOS is also able to bind phospholipids. This association is restricted to anionic species such as phosphatidylcholine. Ohashi et al. (117) showed that these phospholipids enhanced eNOS activity. In contrast, Venema and co-workers (158) showed a decrease in its activity. They demonstrated that the binding of eNOS to phosphatidylcholine vesicles prevented the interaction of the enzyme with calmodulin. Calmodulin and the phospholipids bound eNOS at the same site. Whether the association of eNOS with phospholipids has some physiological relevance remains to be shown. It is difficult to envision a role for phosphatidylcholine in the regulation of eNOS, because caveolar membranes are virtually devoid of phospholipids (122). Perhaps phospholipids prevent eNOS activation in the Golgi complex. Another lipid molecule that binds eNOS and modifies its activity in vitro is oleic acid (33). Whether this fatty acid has some significant role in eNOS regulation in vivo also remains to be determined.
![]() |
CONCLUDING REMARKS |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
There is a large and rapidly expanding amount of data on
eNOS cell biology. A model based on the published eNOS data is depicted in Fig. 3. However, still very little is
known about the exact eNOS regulation within the cell. The most
important reason for this is that a considerable amount of data
generated by different groups is contradictory. Many conclusions that
are drawn from cell-free in vitro systems may not turn out to be true
for the in vivo situation. Similarly, certain interactions may not
exist in vivo but might be introduced during the experimental
procedures, which are used for studying the in vivo material. Cell
culture techniques will also definitely have their impact on eNOS
function and regulation (48, 149). Furthermore, insight
into the mechanisms of regulation are impeded by the fact that eNOS
expression and regulation might be dependent on the vascular bed, from
which the endothelial cells are derived. This is reflected by the
different localization of eNOS within various vessel types
(5). In addition, different vessel types also display a
different number of caveolae, suggesting that the kinetics of eNOS
activation is dependent on the origin of the endothelium. With regard
to the kidney, regulatory information is almost absent despite the
crucial role of eNOS in normal renal physiology.
|
In general, eNOS activity is first of all modulated by the presence of its substrates and cofactors within the cell. These factors determine whether eNOS is a NO- or superoxide-producing enzyme. In addition, eNOS activity is affected by agents and conditions that affect its expression and by its attachment to the membrane, its cellular localization, phosphorylation events, and multiple protein-protein interactions. Of course, these determinants are highly interlinked within the cell and provide a complex regulatory network. The main challenge now will be to unravel this network.
![]() |
ACKNOWLEDGEMENTS |
---|
R. Govers is supported by a grant from the Netherlands Organization for Scientific Research (NWO).
![]() |
FOOTNOTES |
---|
Address for reprint requests and other correspondence: R. Govers, Dept. of Vascular Medicine, Univ. Medical Center Utrecht, Academic Hospital Utrecht-G02.228, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands (E-mail: R.M.T.Govers{at}LAB.AZU.NL).
The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
![]() |
REFERENCES |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
1.
Abu-Soud, HM,
and
Stuehr DJ.
Nitric oxide synthases reveal a role for calmodulin in controlling electron transfer.
Proc Natl Acad Sci USA
90:
10769-10772,
1993[Abstract].
2.
Ahn, KY,
Mohaupt MG,
Madsen KM,
and
Kone BC.
In situ hybridization localization of mRNA encoding inducible nitric oxide synthase in rat kidney.
Am J Physiol Renal Fluid Electrolyte Physiol
267:
F748-F757,
1994
3.
Alonso, J,
Sanchez de Miguel L,
Monton M,
Casado S,
and
Lopez-Farre A.
Endothelial cytosolic proteins bind to the 3' untranslated region of endothelial nitric oxide synthase mRNA: regulation by tumor necrosis factor alpha.
Mol Cell Biol
17:
5719-5726,
1997[Abstract].
4.
Anderson, RG.
Caveolae: where incoming and outgoing messengers meet.
Proc Natl Acad Sci USA
90:
10909-10913,
1993[Abstract].
5.
Andries, LJ,
Brutsaert DL,
and
Sys SU.
Nonuniformity of endothelial constitutive nitric oxide synthase distribution in cardiac endothelium.
Circ Res
82:
195-203,
1998
6.
Arnal, JF,
Yamin J,
Dockery S,
and
Harrison DG.
Regulation of endothelial nitric oxide synthase mRNA, protein, and activity during cell growth.
Am J Physiol Cell Physiol
267:
C1381-C1388,
1994
7.
Awolesi, MA,
Sessa WC,
and
Sumpio BE.
Cyclic strain upregulates nitric oxide synthase in cultured bovine aortic endothelial cells.
J Clin Invest
96:
1449-1454,
1995[ISI][Medline].
8.
Ayajiki, K,
Kindermann M,
Hecker M,
Fleming I,
and
Busse R.
Intracellular pH and tyrosine phosphorylation but not calcium determine shear stress-induced nitric oxide production in native endothelial cells.
Circ Res
78:
750-758,
1996
9.
Barton, M,
Luscher TF,
and
Rabelink TJ.
Say NO to hypertension.
Science
281:
1961,
1998.
10.
Bilderback, TR,
Gazula VR,
Lisanti MP,
and
Dobrowsky RT.
Caveolin interacts with Trk A and p75(NTR) and regulates neurotrophin signaling pathways.
J Biol Chem
274:
257-263,
1999
11.
Blair, A,
Shaul PW,
Yuhanna IS,
Conrad PA,
and
Smart EJ.
Oxidized low density lipoprotein displaces endothelial nitric-oxide synthase (eNOS) from plasmalemmal caveolae and impairs eNOS activation.
J Biol Chem
274:
32512-32519,
1999
12.
Bloch, KD.
Regulation of endothelial NO synthase mRNA stability: RNA-binding proteins crowd on the 3'-untranslated region.
Circ Res
85:
653-665,
1999
13.
Bouloumie, A,
Schinikerth VB,
and
Busse R.
Vascular endothelial growth factor up-regulates nitric oxide synthase expression in endothelial cells.
Cardiovasc Res
41:
773-780,
1999[ISI][Medline].
14.
Braam, B.
Renal endothelial and macula densa NOS: integrated response to changes in extracellular fluid volume.
Am J Physiol Regulatory Integrative Comp Physiol
276:
R1551-R1561,
1999
15.
Brezis, M,
Heyman SN,
Dinour D,
Epstein FH,
and
Rosen S.
Role of nitric oxide in renal medullary oxygenation. Studies in isolated and intact rat kidneys.
J Clin Invest
88:
390-395,
1991[ISI][Medline].
16.
Brock, TA,
and
Capasso EA.
Thrombin and histamine activate phospholipase C in human endothelial cells via a phorbol ester-sensitive pathway.
J Cell Physiol
136:
54-62,
1988[ISI][Medline].
17.
Bruning, TA,
Chang PC,
Blauw GJ,
Vermeij P,
and
van Zwieten PA.
Serotonin-induced vasodilatation in the human forearm is mediated by the "nitric oxide-pathway": no evidence for involvement of the 5-HT3-receptor.
J Cardiovasc Pharmacol
22:
44-51,
1993[ISI][Medline].
18.
Buckley, BJ,
Mirza Z,
and
Whorton AR.
Regulation of Ca(2+)-dependent nitric oxide synthase in bovine aortic endothelial cells.
Am J Physiol Cell Physiol
269:
C757-C765,
1995[Abstract].
19.
Buga, GM,
Griscavage JM,
Rogers NE,
and
Ignarro LJ.
Negative feedback regulation of endothelial cell function by nitric oxide.
Circ Res
73:
808-812,
1993[Abstract].
20.
Casino, PR,
Kilcoyne CM,
Quyyumi AA,
Hoeg JM,
and
Panza JA.
The role of nitric oxide in endothelium-dependent vasodilation of hypercholesterolemic patients.
Circulation
88:
2541-2547,
1993[Abstract].
21.
Chen, KD,
Li YS,
Kim M,
Li S,
Yuan S,
Chien S,
and
Shyy JY.
Mechanotransduction in response to shear stress. Roles of receptor tyrosine kinases, integrins, and Shc.
J Biol Chem
274:
18393-18400,
1999
22.
Chen, Z,
Yuhanna IS,
Galchevagargova Z,
Karas RH,
Mendelsohn RE,
and
Shaul PW.
Estrogen receptor alpha mediates the nongenomic activation of endothelial nitric oxide synthase by estrogen.
J Clin Invest
103:
401-406,
1999
23.
Chen, ZP,
Mitchelhill KI,
Michell BJ,
Stapleton D,
Rodriguez-Crespo I,
Witters LA,
Power DA,
Ortiz de Montellano PR,
and
Kemp BE.
AMP-activated protein kinase phosphorylation of endothelial NO synthase.
FEBS Lett
443:
285-289,
1999[ISI][Medline].
24.
Chin, SY,
Pandey KN,
Shi SJ,
Kobori H,
Moreno C,
and
Navar LG.
Increased activity and expression of Ca2+-dependent NOS in renal cortex of ANG II-infused hypertensive rats.
Am J Physiol Renal Physiol
277:
F797-F804,
1999
25.
Cieslik, K,
Lee CM,
Tang JL,
and
Wu KK.
Transcriptional regulation of endothelial nitric-oxide synthase by an interaction between casein kinase 2 and protein phosphatase 2A.
J Biol Chem
274:
34669-34675,
1999
26.
Conrad, PA,
Smart EJ,
Ying YS,
Anderson RG,
and
Bloom GS.
Caveolin cycles between plasma membrane caveolae and the Golgi complex by microtubule-dependent and microtubule-independent steps.
J Cell Biol
131:
1421-1433,
1995[Abstract].
27.
Cooke, JP,
Rossitch E, Jr,
Andon NA,
Loscalzo J,
and
Dzau VJ.
Flow activates an endothelial potassium channel to release an endogenous nitrovasodilator.
J Clin Invest
88:
1663-1671,
1991[ISI][Medline].
28.
Corson, MA,
James NL,
Latta SE,
Nerem RM,
Berk BC,
and
Harrison DG.
Phosphorylation of endothelial nitric oxide synthase in response to fluid shear stress.
Circ Res
79:
984-991,
1996
29.
Couet, J,
Li S,
Okamoto T,
Ikezu T,
and
Lisanti MP.
Identification of peptide and protein ligands for the caveolin- scaffolding domain. Implications for the interaction of caveolin with caveolae-associated proteins.
J Biol Chem
272:
6525-6533,
1997
30.
Couet, J,
Sargiacomo M,
and
Lisanti MP.
Interaction of a receptor tyrosine kinase, EGF-R, with caveolins. Caveolin binding negatively regulates tyrosine and serine/threonine kinase activities.
J Biol Chem
272:
30429-30438,
1997
31.
Creager, MA,
Gallagher SJ,
Girerd XJ,
Coleman SM,
Dzau VJ,
and
Cooke JP.
L-Arginine improves endothelium-dependent vasodilation in hypercholesterolemic humans.
J Clin Invest
90:
1248-1253,
1992[ISI][Medline].
32.
Danthuluri, NR,
Cybulsky MI,
and
Brock TA.
ACh-induced calcium transients in primary cultures of rabbit aortic endothelial cells.
Am J Physiol Heart Circ Physiol
255:
H1549-H1553,
1988
33.
Davda, RK,
Stepniakowski KT,
Lu G,
Ullian ME,
Goodfriend TL,
and
Egan BM.
Oleic acid inhibits endothelial nitric oxide synthase by a protein kinase C-independent mechanism.
Hypertension
26:
764-770,
1995
34.
Deliconstantinos, G,
Villiotou V,
and
Stavrides JC.
Modulation of particulate nitric oxide synthase activity and peroxynitrite synthesis in cholesterol enriched endothelial cell membranes.
Biochem Pharmacol
49:
1589-1600,
1995[ISI][Medline].
35.
Deng, A,
and
Baylis C.
Locally produced EDRF controls preglomerular resistance and ultrafiltration coefficient.
Am J Physiol Renal Fluid Electrolyte Physiol
264:
F212-F215,
1993
36.
De Weerd, WF,
and
Leeb-Lundberg LM.
Bradykinin sequesters B2 bradykinin receptors and the receptor-coupled Galpha subunits Galphaq and Galphai in caveolae in DDT1 MF-2 smooth muscle cells.
J Biol Chem
272:
17858-17866,
1997
37.
Dijkhorst-Oei, LT,
Rabelink TJ,
Boer P,
and
Koomans HA.
Nifedipine attenuates systemic and renal vasoconstriction during nitric oxide inhibition in humans.
Hypertension
29:
1192-1198,
1997
38.
Dimmeler, S,
Fleming I,
Fisslthaler B,
Hermann C,
Busse R,
and
Zeiher AM.
Activation of nitric oxide synthase in endothelial cells by Akt-dependent phosphorylation.
Nature
399:
601-605,
1999[ISI][Medline].
39.
Drummond, GR,
Cai H,
Davis ME,
Ramasamy S,
and
Harrison DG.
Transcriptional and posttranscriptional regulation of endothelial nitric oxide synthase expression by hydrogen peroxide.
Circ Res
86:
347-354,
2000
40.
Engelman, JA,
Chu C,
Lin A,
Jo H,
Ikezu T,
Okamoto T,
Kohtz DS,
and
Lisanti MP.
Caveolin-mediated regulation of signaling along the p42/44 MAP kinase cascade in vivo. A role for the caveolin-scaffolding domain.
FEBS Lett
428:
205-211,
1998[ISI][Medline].
41.
Etscheid, BG,
and
Villereal ML.
Coupling of bradykinin receptors to phospholipase C in cultured fibroblasts is mediated by a G-protein.
J Cell Physiol
140:
264-271,
1989[ISI][Medline].
42.
Feng, Y,
Venema VJ,
Venema RC,
Tsai N,
Behzadian MA,
and
Caldwell RB.
VEGF-induced permeability increase is mediated by caveolae.
Invest Ophthalmol Vis Sci
40:
157-167,
1999[Abstract].
43.
Feron, O,
Dessy C,
Moniotte S,
Desager JP,
and
Balligand JL.
Hypercholesterolemia decreases nitric oxide production by promoting the interaction of caveolin and endothelial nitric oxide synthase.
J Clin Invest
103:
897-905,
1999
44.
Feron, O,
Michel JB,
Sase K,
and
Michel T.
Dynamic regulation of endothelial nitric oxide synthase: complementary roles of dual acylation and caveolin interactions.
Biochemistry
37:
193-200,
1998[ISI][Medline].
45.
Feron, O,
Saldana F,
Michel JB,
and
Michel T.
The endothelial nitric-oxide synthase-caveolin regulatory cycle.
J Biol Chem
273:
3125-3128,
1998
46.
Feron, O,
Smith TW,
Michel T,
and
Kelly RA.
Dynamic targeting of the agonist-stimulated m2 muscarinic acetylcholine receptor to caveolae in cardiac myocytes.
J Biol Chem
272:
17744-17748,
1997
47.
Fischer, S,
Clauss M,
Wiesnet M,
Renz D,
Schaper W,
and
Karliczek GF.
Hypoxia induces permeability in brain microvessel endothelial cells via VEGF and NO.
Am J Physiol Cell Physiol
276:
C812-C820,
1999
48.
Fleming, I,
Bauersachs J,
Fisslthaler B,
and
Busse R.
Ca2+-independent activation of the endothelial nitric oxide synthase in response to tyrosine phosphatase inhibitors and fluid shear stress.
Circ Res
82:
686-695,
1998
49.
Fleming, I,
Bauersachs J,
Schafer A,
Scholz D,
Aldershvile J,
and
Busse R.
Isometric contraction induces the Ca2+-independent activation of the endothelial nitric oxide synthase.
Proc Natl Acad Sci USA
96:
1123-1128,
1999
50.
Fra, AM,
Williamson E,
Simons K,
and
Parton RG.
Detergent-insoluble glycolipid microdomains in lymphocytes in the absence of caveolae.
J Biol Chem
269:
30745-30748,
1994
51.
Fujimoto, T.
Calcium pump of the plasma membrane is localized in caveolae.
J Cell Biol
120:
1147-1157,
1993[Abstract].
52.
Fulton, D,
Gratton JP,
McCabe TJ,
Fontana J,
Fujio Y,
Walsh K,
Franke TF,
Papapetropoulos A,
and
Sessa WC.
Regulation of endothelium-derived nitric oxide production by the protein kinase Akt.
Nature
399:
597-601,
1999[ISI][Medline].
53.
Gallis, B,
Corthals GL,
Goodlett DR,
Ueba H,
Kim F,
Presnell SR,
Figeys D,
Harrison DG,
Berk BC,
Aebersold R,
and
Corson MA.
Identification of flow-dependent endothelial nitric-oxide synthase phosphorylation sites by mass spectrometry and regulation of phosphorylation and nitric oxide production by the phosphatidylinositol 3-kinase inhibitor LY294002.
J Biol Chem
274:
30101-30108,
1999
54.
Garcia-Cardena, G,
Fan R,
Shah V,
Sorrentino R,
Cirino G,
Papapetropoulos A,
and
Sessa WC.
Dynamic activation of endothelial nitric oxide synthase by Hsp90.
Nature
392:
821-824,
1998[ISI][Medline].
55.
Garcia-Cardena, G,
Fan R,
Stern DF,
Liu J,
and
Sessa WC.
Endothelial nitric oxide synthase is regulated by tyrosine phosphorylation and interacts with caveolin-1.
J Biol Chem
271:
27237-27240,
1996
56.
Garcia-Cardena, G,
Martasek P,
Masters BS,
Skidd PM,
Couet J,
Li S,
Lisanti MP,
and
Sessa WC.
Dissecting the interaction between nitric oxide synthase (NOS) and caveolin. Functional significance of the NOS-caveolin binding domain in vivo.
J Biol Chem
272:
25437-25440,
1997
57.
Garcia-Cardena, G,
Oh P,
Liu J,
Schnitzer JE,
and
Sessa WC.
Targeting of nitric oxide synthase to endothelial cell caveolae via palmitoylation: implications for nitric oxide signaling.
Proc Natl Acad Sci USA
93:
6448-6453,
1996
58.
Ghosh, S,
Gachhui R,
Crooks C,
Wu C,
Lisanti MP,
and
Stuehr DJ.
Interaction between caveolin-1 and the reductase domain of endothelial nitric-oxide synthase. Consequences for catalysis.
J Biol Chem
273:
22267-22271,
1998
59.
Goetz, RM,
Thatte HS,
Prabhakar P,
Cho MR,
Michel T,
and
Golan DE.
Estradiol induces the calcium-dependent translocation of endothelial nitric oxide synthase.
Proc Nat Acad Sci USA
96:
2788-2793,
1999
60.
Golser, R,
Gorren AC,
Leber A,
Andrew P,
Habisch HJ,
Werner ER,
Schmidt K,
Venema RC,
and
Mayer B.
Interaction of endothelial and neuronal nitric-oxide synthases with the bradykinin B2 receptor. Binding of an inhibitory peptide to the oxygenase domain blocks uncoupled NADPH oxidation.
J Biol Chem
275:
5291-5296,
2000
61.
Gorodinsky, A,
and
Harris DA.
Glycolipid-anchored proteins in neuroblastoma cells form detergent-resistant complexes without caveolin.
J Cell Biol
129:
619-627,
1995[Abstract].
62.
Gosink, EC,
and
Forsberg EJ.
Effects of ATP and bradykinin on endothelial cell Ca2+ homeostasis and formation of cGMP and prostacyclin.
Am J Physiol Cell Physiol
265:
C1620-C1629,
1993
63.
Gratton, JP,
Fontana J,
O'Connor DS,
Garcia-Cardena G,
McCabe TJ,
and
Sessa WC.
Reconstitution of an endothelial nitric oxide synthase, hsp90 and caveolin-1 complex in vitro: evidence that hsp90 facilitates calmodulin stimulated displacement of eNOS from caveolin-1.
J Biol Chem
275:
22268-22272,
2000
64.
Gustavsson, J,
Parpal S,
Karlsson M,
Ramsing C,
Thorn H,
Borg M,
Lindroth M,
Peterson KH,
Magnusson KE,
and
Stralfors P.
Localization of the insulin receptor in caveolae of adipocyte plasma membrane.
FASEB J
13:
1961-1971,
1999
65.
Heeringa, P,
van Goor H,
Moshage H,
Klok PA,
Huitema MG,
de Jager A,
Schep AJ,
and
Kallenberg CG.
Expression of iNOS, eNOS, and peroxynitrite-modified proteins in experimental anti-myeloperoxidase associated crescentic glomerulonephritis.
Kidney Int
53:
382-393,
1998[ISI][Medline].
66.
Hirata, K,
Kuroda R,
Sakoda T,
Katayama M,
Inoue N,
Suematsu M,
Kawashima S,
and
Yokoyama M.
Inhibition of endothelial nitric oxide synthase activity by protein kinase C.
Hypertension
25:
180-185,
1995
67.
Hirata, K,
Miki N,
Kuroda Y,
Sakoda T,
Kawashima S,
and
Yokoyama M.
Low concentration of oxidized low-density lipoprotein and lysophosphatidylcholine upregulate constitutive nitric oxide synthase mRNA expression in bovine aortic endothelial cells.
Circ Res
76:
958-962,
1995
68.
Huk, I,
Nanobashvili J,
Neumayer C,
Punz A,
Mueller M,
Afkhampour K,
Mittlboeck M,
Losert U,
Polterauer P,
Roth E,
Patton S,
and
Malinski T.
L-Arginine treatment alters the kinetics of nitric oxide and superoxide release and reduces ischemia/reperfusion injury in skeletal muscle.
Circulation
96:
667-675,
1997
69.
Hutcheson, IR,
and
Griffith TM.
Heterogeneous populations of K+ channels mediate EDRF release to flow but not agonists in rabbit aorta.
Am J Physiol Heart Circ Physiol
266:
H590-H596,
1994
70.
Hutcheson, IR,
and
Griffith TM.
Mechanotransduction through the endothelial cytoskeleton: mediation of flow- but not agonist-induced EDRF release.
Br J Pharmacol
118:
720-726,
1996[Abstract].
71.
Igarashi, J,
Thatte HS,
Prabhakar P,
Golan DE,
and
Michel T.
Calcium-independent activation of endothelial nitric oxide synthase by ceramide.
Proc Natl Acad Sci USA
96:
12583-12588,
1999
72.
Inoue, N,
Venema RC,
Sayegh HS,
Ohara Y,
Murphy TJ,
and
Harrison DG.
Molecular regulation of the bovine endothelial cell nitric oxide synthase by transforming growth factor-beta 1.
Arterioscler Thromb Vasc Biol
15:
1255-1261,
1995
73.
Ishii, M,
Shimizu S,
Yamamoto T,
Momose K,
and
Kuroiwa Y.
Acceleration of oxidative stress-induced endothelial cell death by nitric oxide synthase dysfunction accompanied with decrease in tetrahydrobiopterin content.
Life Sci
61:
739-747,
1997[ISI][Medline].
74.
Ito, S,
Arima S,
Ren YL,
Juncos LA,
and
Carretero OA.
Endothelium-derived relaxing factor/nitric oxide modulates angiotensin II action in the isolated microperfused rabbit afferent but not efferent arteriole.
J Clin Invest
91:
2012-2019,
1993[ISI][Medline].
75.
Ito, S,
Carretero OA,
and
Abe K.
Nitric oxide in the juxtaglomerular apparatus.
Kidney Int Suppl
55:
S6-S8,
1996[Medline].
76.
Ju, H,
Venema VJ,
Marrero MB,
and
Venema RC.
Inhibitory interactions of the bradykinin B2 receptor with endothelial nitric-oxide synthase.
J Biol Chem
273:
24025-24029,
1998
77.
Ju, H,
Zou R,
Venema VJ,
and
Venema RC.
Direct interaction of endothelial nitric-oxide synthase and caveolin-1 inhibits synthase activity.
J Biol Chem
272:
18522-18525,
1997
78.
Kakoki, M,
Hirata Y,
Hayakawa H,
Suzuki E,
Nagata D,
Tojo A,
Nishimatsu H,
Nakanishi N,
Hattori Y,
Kikuchi K,
Nagano T,
and
Omata M.
Effects of tetrahydrobiopterin on endothelial dysfunction in rats with ischemic acute renal failure.
J Am Soc Nephrol
11:
301-309,
2000
79.
Kelm, M,
Feelisch M,
Krebber T,
Motz W,
and
Strauer BE.
Mechanisms of histamine-induced coronary vasodilatation: H1-receptor-mediated release of endothelium-derived nitric oxide.
J Vasc Res
30:
132-138,
1993[ISI][Medline].
80.
Kim, HP,
Lee JY,
Jeong JK,
Bae SW,
Lee HK,
and
Jo I.
Nongenomic stimulation of nitric oxide release by estrogen is mediated by estrogen receptor alpha localized in caveolae.
Biochem Biophys Res Commun
263:
257-262,
1999[ISI][Medline].
81.
Kone, BC.
Localization and regulation of nitric oxide synthase isoforms in the kidney.
Semin Nephrol
19:
230-241,
1999[ISI][Medline].
82.
Kone, BC.
Nitric oxide in renal health and disease.
Am J Kidney Dis
30:
311-333,
1997[ISI][Medline].
83.
Kroll, J,
and
Waltenberger J.
VEGF-A induces expression of eNOS and iNOS in endothelial cells via VEGF receptor-2 (KDR).
Biochem Biophys Res Commun
252:
743-746,
1998[ISI][Medline].
84.
Kuboki, K,
Jiang ZY,
Takahara N,
Ha SW,
Igarashi M,
Yamauchi T,
Feener EP,
Herbert TP,
Rhodes CJ,
and
King GL.
Regulation of endothelial constitutive nitric oxide synthase gene expression in endothelial cells and in vivo: a specific vascular action of insulin.
Circulation
101:
676-681,
2000
85.
Kurose, I,
Kubes P,
Wolf R,
Anderson DC,
Paulson J,
Miyasaka M,
and
Granger DN.
Inhibition of nitric oxide production. Mechanisms of vascular albumin leakage.
Circ Res
73:
164-171,
1993[Abstract].
86.
Kurzchalia, TV,
Dupree P,
Parton RG,
Kellner R,
Virta H,
Lehnert M,
and
Simons K.
VIP21, a 21-kD membrane protein is an integral component of trans-Golgi-network-derived transport vesicles.
J Cell Biol
118:
1003-1014,
1992[Abstract].
87.
Landreth, GE,
Williams LK,
and
Rieser GD.
Association of the epidermal growth factor receptor kinase with the detergent-insoluble cytoskeleton of A431 cells.
J Cell Biol
101:
1341-1350,
1985[Abstract].
88.
Laufs, U,
La Fata V,
Plutzky J,
and
Liao JK.
Upregulation of endothelial nitric oxide synthase by HMG CoA reductase inhibitors.
Circulation
97:
1129-1135,
1998
89.
Li, S,
Couet J,
and
Lisanti MP.
Src tyrosine kinases, Galpha subunits, and H-Ras share a common membrane-anchored scaffolding protein, caveolin. Caveolin binding negatively regulates the auto-activation of Src tyrosine kinases.
J Biol Chem
271:
29182-29190,
1996
90.
Li, S,
Okamoto T,
Chun M,
Sargiacomo M,
Casanova JE,
Hansen SH,
Nishimoto I,
and
Lisanti MP.
Evidence for a regulated interaction between heterotrimeric G proteins and caveolin.
J Biol Chem
270:
15693-15701,
1995
91.
Liao, JK,
Shin WS,
Lee WY,
and
Clark SL.
Oxidized low-density lipoprotein decreases the expression of endothelial nitric oxide synthase.
J Biol Chem
270:
319-324,
1995
92.
Liu, J,
Garcia Cardena G,
and
Sessa WC.
Biosynthesis and palmitoylation of endothelial nitric oxide synthase: mutagenesis of palmitoylation sites, cysteines-15 and/or -26, argues against depalmitoylation-induced translocation of the enzyme.
Biochemistry
34:
12333-12340,
1995[ISI][Medline].
93.
Liu, J,
Garcia-Cardena G,
and
Sessa WC.
Palmitoylation of endothelial nitric oxide synthase is necessary for optimal stimulated release of nitric oxide: implications for caveolae localization.
Biochemistry
35:
13277-13281,
1996[ISI][Medline].
94.
Liu, J,
Hughes TE,
and
Sessa WC.
The first 35 amino acids and fatty acylation sites determine the molecular targeting of endothelial nitric oxide synthase into the Golgi region of cells: a green fluorescent protein study.
J Cell Biol
137:
1525-1535,
1997
95.
Liu, J,
Oh P,
Horner T,
Rogers RA,
and
Schnitzer JE.
Organized endothelial cell surface signal transduction in caveolae distinct from glycosylphosphatidylinositol-anchored protein microdomains.
J Biol Chem
272:
7211-7222,
1997
96.
Liu, SM,
and
Sundqvist T.
Nitric oxide and cGMP regulate endothelial permeability and F-actin distribution in hydrogen peroxide-treated endothelial cells.
Exp Cell Res
235:
238-244,
1997[ISI][Medline].
97.
Lu, JL,
Schmiege LM, 3rd,
Kuo L,
and
Liao JC.
Downregulation of endothelial constitutive nitric oxide synthase expression by lipopolysaccharide.
Biochem Biophys Res Commun
225:
1-5,
1996[ISI][Medline].
98.
Marrero, MB,
Venema VJ,
Ju H,
He H,
Liang HY,
Caldwell RB,
and
Venema RC.
Endothelial nitric oxide synthase interactions with G-protein-coupled receptors.
Biochem J
343:
335-340,
1999[ISI][Medline].
99.
Marsden, PA,
Heng HH,
Scherer SW,
Stewart RJ,
Hall AV,
Shi XM,
Tsui LC,
and
Schappert KT.
Structure and chromosomal localization of the human constitutive endothelial nitric oxide synthase gene.
J Biol Chem
268:
17478-17488,
1993
100.
Mashiach, E,
Sela S,
Winaver J,
Shasha SM,
and
Kristal B.
Renal ischemia-reperfusion injury: contribution of nitric oxide and renal blood flow.
Nephron
80:
458-467,
1998[ISI][Medline].
101.
Mattson, DL,
Roman RJ,
and
Cowley AW, Jr.
Role of nitric oxide in renal papillary blood flow and sodium excretion.
Hypertension
19:
766-769,
1992[Abstract].
102.
Mattson, DL,
and
Wu F.
Nitric oxide synthase activity and isoforms in rat renal vasculature.
Hypertension
35:
337-341,
2000
103.
McCabe, TJ,
Fulton D,
Roman LJ,
and
Sessa WC.
Enhanced electron flux and reduced calmodulin dissociation may explain "calcium-independent" eNOS activation by phosphorylation.
J Biol Chem
275:
6123-6128,
2000
104.
McDonald, KK,
Zharikov S,
Block ER,
and
Kilberg MS.
A caveolar complex between the cationic amino acid transporter 1 and endothelial nitric-oxide synthase may explain the "arginine paradox."
J Biol Chem
272:
31213-31216,
1997
105.
McQuillan, LP,
Leung GK,
Marsden PA,
Kostyk SK,
and
Kourembanas S.
Hypoxia inhibits expression of eNOS via transcriptional and posttranscriptional mechanisms.
Am J Physiol Heart Circ Physiol
267:
H1921-H1927,
1994
106.
Michel, JB,
Feron O,
Sacks D,
and
Michel T.
Reciprocal regulation of endothelial nitric-oxide synthase by Ca2+-calmodulin and caveolin.
J Biol Chem
272:
15583-15586,
1997
107.
Michel, JB,
Feron O,
Sase K,
Prabhakar P,
and
Michel T.
Caveolin versus calmodulin. Counterbalancing allosteric modulators of endothelial nitric oxide synthase.
J Biol Chem
272:
25907-25912,
1997
108.
Michel, T,
Li GK,
and
Busconi L.
Phosphorylation and subcellular translocation of endothelial nitric oxide synthase.
Proc Natl Acad Sci USA
90:
6252-6256,
1993[Abstract].
109.
Michell, BJ,
Griffiths JE,
Mitchelhill KI,
Rodriguez-Crespo I,
Tiganis T,
Bozinovski S,
de Montellano PR,
Kemp BE,
and
Pearson RB.
The Akt kinase signals directly to endothelial nitric oxide synthase.
Curr Biol
12:
845-848,
1999.
110.
Mineo, C,
Gill GN,
and
Anderson GW.
Regulated migration of epidermal growth factor receptor from caveolae.
J Biol Chem
274:
30636-30643,
1999
111.
Mitani, Y,
Maruyama K,
and
Sakurai M.
Prolonged administration of L-arginine ameliorates chronic pulmonary hypertension and pulmonary vascular remodeling in rats.
Circulation
96:
689-697,
1997
112.
Navarro-Antolin, J,
Rey-Campos J,
and
Lamas S.
Transcriptional induction of endothelial nitric oxide gene by cyclosporine A. A role for activator protein-1.
J Biol Chem
275:
3075-3080,
2000
113.
Ni, Z,
Wang XQ,
and
Vaziri ND.
Nitric oxide metabolism in erythropoietin-induced hypertension: effect of calcium channel blockade.
Hypertension
32:
724-729,
1998
114.
Nishida, K,
Harrison DG,
Navas JP,
Fisher AA,
Dockery SP,
Uematsu M,
Nerem RM,
Alexander RW,
and
Murphy TJ.
Molecular cloning and characterization of the constitutive bovine aortic endothelial cell nitric oxide synthase.
J Clin Invest
90:
2092-2096,
1992[ISI][Medline].
115.
Noris, M,
Morigi M,
Donadelli R,
Aiello S,
Foppolo M,
Todeschini M,
Orisio S,
Remuzzi G,
and
Remuzzi A.
Nitric oxide synthesis by cultured endothelial cells is modulated by flow conditions.
Circ Res
76:
536-543,
1995
116.
Ohara, Y,
Sayegh HS,
Yamin JJ,
and
Harrison DG.
Regulation of endothelial constitutive nitric oxide synthase by protein kinase C.
Hypertension
25:
415-420,
1995
117.
Ohashi, Y,
Katayama M,
Hirata K,
Suematsu M,
Kawashima S,
and
Yokoyama M.
Activation of nitric oxide synthase from cultured aortic endothelial cells by phospholipids.
Biochem Biophys Res Commun
195:
1314-1320,
1993[ISI][Medline].
118.
Ohno, M,
Gibbons GH,
Dzau VJ,
and
Cooke JP.
Shear stress elevates endothelial cGMP. Role of a potassium channel and G protein coupling.
Circulation
88:
193-197,
1993[Abstract].
119.
Palmer, RM,
Ashton DS,
and
Moncada S.
Vascular endothelial cells synthesize nitric oxide from L-arginine.
Nature
333:
664-666,
1988[ISI][Medline].
120.
Papapetropoulos, A,
Garciacardena G,
Madri JA,
and
Sessa WC.
Nitric oxide production contributes to the angiogenic properties of vascular endothelial growth factor in human endothelial cells.
J Clin Invest
100:
3131-3139,
1997
121.
Parton, RG.
Caveolae and caveolins.
Curr Opin Cell Biol
8:
542-548,
1996[ISI][Medline].
122.
Parton, RG,
and
Simons K.
Digging into caveolae.
Science
269:
1398-1399,
1995[ISI][Medline].
123.
Peterson, TE,
Poppa V,
Ueba H,
Wu A,
Yan C,
and
Berk BC.
Opposing effects of reactive oxygen species and cholesterol on endothelial nitric oxide synthase and endothelial cell caveolae.
Circ Res
85:
29-37,
1999
124.
Plato, CF,
Shesely EG,
and
Garvin JL.
eNOS mediates L-arginine-induced inhibition of thick ascending limb chloride flux.
Hypertension
35:
319-323,
2000
125.
Pou, S,
Keaton L,
Surichamorn W,
and
Rosen GM.
Mechanism of superoxide generation by neuronal nitric-oxide synthase.
J Biol Chem
274:
9573-9580,
1999
126.
Pou, S,
Pou WS,
Bredt DS,
Snyder SH,
and
Rosen GM.
Generation of superoxide by purified brain nitric oxide synthase.
J Biol Chem
267:
24173-24176,
1992
127.
Prabhakar, P,
Thatte HS,
Goetz RM,
Cho MR,
Golan DE,
and
Michel T.
Receptor-regulated translocation of endothelial nitric-oxide synthase.
J Biol Chem
273:
27383-27388,
1998
128.
Pratt, WB.
The role of the hsp90-based chaperone system in signal transduction by nuclear receptors and receptors signaling via MAP kinase.
Annu Rev Pharmacol Toxicol
37:
297-326,
1997[ISI][Medline].
129.
Rahman, MM,
Varghese Z,
Fuller BJ,
and
Moorhead JF.
Renal vasoconstriction induced by oxidized LDL is inhibited by scavengers of reactive oxygen species and L-arginine.
Clin Nephrol
51:
98-107,
1999[ISI][Medline].
130.
Raman, CS,
Li HY,
Martasek P,
Kral V,
Masters BSS,
and
Poulos TL.
Crystal structure of constitutive endothelial nitric oxide synthase: a paradigm for pterin function involving a novel metal center.
Cell
95:
939-950,
1998[ISI][Medline].
131.
Rizzo, V,
McIntosh DP,
Oh P,
and
Schnitzer JE.
In situ flow activates endothelial nitric oxide synthase in luminal caveolae of endothelium with rapid caveolin dissociation and calmodulin association.
J Biol Chem
273:
34724-34729,
1998
132.
Rizzo, V,
Sung A,
Oh P,
and
Schnitzer JE.
Rapid mechanotransduction in situ at the luminal cell surface of vascular endothelium and its caveolae.
J Biol Chem
273:
26323-26329,
1998
133.
Robinson, LJ,
and
Michel T.
Mutagenesis of palmitoylation sites in endothelial nitric oxide synthase identifies a novel motif for dual acylation and subcellular targeting.
Proc Natl Acad Sci USA
92:
11776-11780,
1995[Abstract].
134.
Robinson, LJ,
Weremowicz S,
Morton CC,
and
Michel T.
Isolation and chromosomal localization of the human endothelial nitric oxide synthase (NOS3) gene.
Genomics
19:
350-357,
1994[ISI][Medline].
135.
Roman, RJ,
and
Zou AP.
Influence of the renal medullary circulation on the control of sodium excretion.
Am J Physiol Regulatory Integrative Comp Physiol
265:
R963-R973,
1993
136.
Sakoda, T,
Hirata K,
Kuroda R,
Miki N,
Suematsu M,
Kawashima S,
and
Yokoyama M.
Myristoylation of endothelial cell nitric oxide synthase is important for extracellular release of nitric oxide.
Mol Cell Biochem
152:
143-148,
1995[ISI][Medline].
137.
Salom, MG,
Lahera V,
Miranda-Guardiola F,
and
Romero JC.
Blockade of pressure natriuresis induced by inhibition of renal synthesis of nitric oxide in dogs.
Am J Physiol Renal Fluid Electrolyte Physiol
262:
F718-F722,
1992
138.
Schnitzer, JE,
McIntosh DP,
Dvorak AM,
Liu J,
and
Oh P.
Separation of caveolae from associated microdomains of GPI-anchored proteins.
Science
269:
1435-1439,
1995[ISI][Medline].
139.
Schwartz, D,
Mendonca M,
Schwartz I,
Xia Y,
Satriano J,
Wilson CB,
and
Blantz RC.
Inhibition of constitutive nitric oxide synthase (NOS) by nitric oxide generated by inducible NOS after lipopolysaccharide administration provokes renal dysfunction in rats.
J Clin Invest
100:
439-448,
1997
140.
Sessa, WC,
Garcia-Cardena G,
Liu J,
Keh A,
Pollock JS,
Bradley J,
Thiru S,
Braverman IM,
and
Desai KM.
The Golgi association of endothelial nitric oxide synthase is necessary for the efficient synthesis of nitric oxide.
J Biol Chem
270:
17641-17644,
1995
141.
Sessa, WC,
Harrison JK,
Barber CM,
Zeng D,
Durieux ME,
D'Angelo DD,
Lynch KR,
and
Peach MJ.
Molecular cloning and expression of a cDNA encoding endothelial cell nitric oxide synthase.
J Biol Chem
267:
15274-15276,
1992
142.
Shah, V,
Wiest R,
Garcia-Cardena G,
Cadelina G,
Groszmann RJ,
and
Sessa WC.
Hsp90 regulation of endothelial nitric oxide synthase contributes to vascular control in portal hypertension.
Am J Physiol Gastrointest Liver Physiol
277:
G463-G468,
1999
143.
Shaul, PW,
Smart EJ,
Robinson LJ,
German Z,
Yuhanna IS,
Ying Y,
Anderson RG,
and
Michel T.
Acylation targets endothelial nitric-oxide synthase to plasmalemmal caveolae.
J Biol Chem
271:
6518-6522,
1996
144.
Smart, EJ,
Graf GA,
McNiven MA,
Sessa WC,
Engelman JA,
Scherer PE,
Okamoto T,
and
Lisanti MP.
Caveolins, liquid-ordered domains, and signal transduction.
Mol Cell Biol
19:
7289-7304,
1999
145.
Sowa, G,
Liu J,
Papapetropoulos A,
Rex-Haffner M,
Hughes TE,
and
Sessa WC.
Trafficking of endothelial nitric-oxide synthase in living cells. Quantitative evidence supporting the role of palmitoylation as a kinetic trapping mechanism limiting membrane diffusion.
J Biol Chem
274:
22524-22531,
1999
146.
Stanboli, A,
and
Morin AM.
Nitric oxide synthase in cerebrovascular endothelial cells is inhibited by brefeldin A.
Neurosci Lett
171:
209-212,
1994[ISI][Medline].
147.
Stroes, E,
Hijmering M,
Vanzandvoort M,
Wever R,
Rabelink TJ,
and
Vanfaassen EE.
Origin of superoxide production by endothelial nitric oxide synthase.
FEBS Lett
438:
161-164,
1998[ISI][Medline].
148.
Stroes, E,
Kastelein J,
Cosentino F,
Erkelens W,
Wever R,
Koomans H,
Luscher T,
and
Rabelink T.
Tetrahydrobiopterin restores endothelial function in hypercholesterolemia.
J Clin Invest
99:
41-46,
1997
149.
Sung, CP,
Arleth AJ,
Shikano K,
Zabko-Potapovich B,
and
Berkowitz BA.
Effect of trypsinization in cell culture on bradykinin receptors in vascular endothelial cells.
Biochem Pharmacol
38:
696-699,
1989[ISI][Medline].
150.
Tan, EQ,
Gurjar MV,
Sharma RV,
and
Bhalla RC.
Estrogen receptor-alpha gene transfer into bovine aortic endothelial cells induces eNOS gene expression and inhibits cell migration.
Cardiovasc Res
43:
788-797,
1999[ISI][Medline].
151.
Teichert, AM,
Miller TL,
Tai SC,
Wang Y,
Bei X,
Robb GB,
Phillips MJ,
and
Marsden PA.
In vivo expression profile of an endothelial nitric oxide synthase promoter-reporter transgene.
Am J Physiol Heart Circ Physiol
278:
H1352-H1361,
2000
152.
Toyoshima, H,
Nasa Y,
Hashizume Y,
Koseki Y,
Isayama Y,
Kohsaka Y,
Yamada T,
and
Takeo S.
Modulation of cAMP-mediated vasorelaxation by endothelial nitric oxide and basal cGMP in vascular smooth muscle.
J Cardiovasc Pharmacol
32:
543-551,
1998[ISI][Medline].
153.
Traylor, LA,
and
Mayeux PR.
Superoxide generation by renal proximal tubule nitric oxide synthase.
Nitric Oxide
1:
432-438,
1997[ISI][Medline].
154.
Vasquez-Vivar, J,
Hogg N,
Martasek P,
Karoui H,
Pritchard KA, Jr,
and
Kalyanaraman B.
Tetrahydrobiopterin-dependent inhibition of superoxide generation from neuronal nitric oxide synthase.
J Biol Chem
274:
26736-26742,
1999
155.
Vasquez-Vivar, J,
Kalyanaraman B,
Martasek P,
Hogg N,
Masters BSS,
Karoui H,
Tordo P,
and
Pritchard KA.
Superoxide generation by endothelial nitric oxide synthase: the influence of cofactors.
Proc Natl Acad Sci USA
95:
9220-9225,
1998
156.
Vaziri, ND,
Ding Y,
and
Ni Z.
Nitric oxide synthase expression in the course of lead-induced hypertension.
Hypertension
34:
558-62,
1999
157.
Vaziri, ND,
and
Wang XQ.
cGMP-mediated negative-feedback regulation of endothelial nitric oxide synthase expression by nitric oxide.
Hypertension
34:
1237-1241,
1999
158.
Venema, RC,
Sayegh HS,
Arnal JF,
and
Harrison DG.
Role of the enzyme calmodulin-binding domain in membrane association and phospholipid inhibition of endothelial nitric oxide synthase.
J Biol Chem
270:
14705-14711,
1995
159.
Venema, VJ,
Marrero MB,
and
Venema RC.
Bradykinin-stimulated protein tyrosine phosphorylation promotes endothelial nitric oxide synthase translocation to the cytoskeleton.
Biochem Biophys Res Commun
226:
703-710,
1996[ISI][Medline].
160.
Venema, VJ,
Zou R,
Ju H,
Marrero MB,
and
Venema RC.
Caveolin-1 detergent solubility and association with endothelial nitric oxide synthase is modulated by tyrosine phosphorylation.
Biochem Biophys Res Commun
236:
155-161,
1997[ISI][Medline].
161.
Verhagen, AM,
Rabelink TJ,
Braam B,
Opgenorth TJ,
Grone HJ,
Koomans HA,
and
Joles JA.
Endothelin A receptor blockade alleviates hypertension and renal lesions associated with chronic nitric oxide synthase inhibition.
J Am Soc Nephrol
9:
755-762,
1998[Abstract].
162.
Vos, I,
Joles JA,
Schurink M,
Weckbecker M,
Stajanovic T,
Rabelink TJ,
and
Grone HJ.
Inhibition of inducible nitric oxide synthase improves graft function and reduces tubulointerstitial injury in renal allograft rejection.
Eur J Pharmacol
391:
31-38,
2000[ISI][Medline].
163.
Wang, XQ,
and
Vaziri ND.
Erythropoietin depresses nitric oxide synthase expression by human endothelial cells.
Hypertension
33:
894-899,
1999
164.
Waugh, MG,
Lawson D,
and
Hsuan JJ.
Epidermal growth factor receptor activation is localized within low-buoyant density, non-caveolar membrane domains.
Biochem J
337:
591-597,
1999[ISI][Medline].
165.
Wever, RMF,
van Dam T,
van Rijn HJ,
de Groot F,
and
Rabelink TJ.
Tetrahydrobiopterin regulates superoxide and nitric oxide generation by recombinant endothelial nitric oxide synthase.
Biochem Biophys Res Commun
237:
340-344,
1997[ISI][Medline].
166.
Woda, BA,
and
McFadden ML.
Ligand-induced association of rat lymphocyte membrane proteins with the detergent-insoluble lymphocyte cytoskeletal matrix.
J Immunol
131:
1917-1919,
1983
167.
Xia, Y,
Roman LJ,
Masters BS,
and
Zweier JL.
Inducible nitric-oxide synthase generates superoxide from the reductase domain.
J Biol Chem
273:
22635-22639,
1998
168.
Yamamoto, M,
Toya Y,
Jensen RA,
and
Ishikawa Y.
Caveolin is an inhibitor of platelet-derived growth factor receptor signaling.
Exp Cell Res
247:
380-388,
1999[ISI][Medline].
169.
Yan, SR,
Fumagalli L,
and
Berton G.
Activation of SRC family kinases in human neutrophils. Evidence that p58C-FGR and p53/56LYN redistributed to a Triton X-100-insoluble cytoskeletal fraction, also enriched in the caveolar protein caveolin, display an enhanced kinase activity.
FEBS Lett
380:
198-203,
1996[ISI][Medline].
170.
Yeh, DC,
Duncan JA,
Yamashita S,
and
Michel T.
Depalmitoylation of endothelial nitric-oxide synthase by acyl-protein thioesterase 1 is potentiated by Ca(2+)-calmodulin.
J Biol Chem
274:
33148-33154,
1999
171.
Zembowicz, A,
Hecker M,
Macarthur H,
Sessa WC,
and
Vane JR.
Nitric oxide and another potent vasodilator are formed from NG-hydroxy-L-arginine by cultured endothelial cells.
Proc Natl Acad Sci USA
88:
11172-11176,
1991[Abstract].
172.
Zembowicz, A,
Tang JL,
and
Wu KK.
Transcriptional induction of endothelial nitric oxide synthase type III by lysophosphatidylcholine.
J Biol Chem
270:
17006-17010,
1995
173.
Zeng, G,
Nystrom FH,
Ravichandran LV,
Cong LN,
Kirby M,
Mostowski H,
and
Quon MJ.
Roles for insulin receptor, PI3-kinase, and Akt in insulin-signaling pathways related to production of nitric oxide in human vascular endothelial cells.
Circulation
101:
1539-1545,
2000
174.
Zeng, G,
and
Quon MJ.
Insulin-stimulated production of nitric oxide is inhibited by wortmannin. Direct measurement in vascular endothelial cells.
J Clin Invest
98:
894-898,
1996
175.
Zheng, J,
Bird IM,
Melsaether AN,
and
Magness RR.
Activation of the mitogen-activated protein kinase cascade is necessary but not sufficient for basic fibroblast growth factor- and epidermal growth factor-stimulated expression of endothelial nitric oxide synthase in ovine fetoplacental artery endothelial cells.
Endocrinology
140:
1399-1407,
1999
176.
Ziegler, T,
Silacci P,
Harrison VJ,
and
Hayoz D.
Nitric oxide synthase expression in endothelial cells exposed to mechanical forces.
Hypertension
32:
351-355,
1998