Department of Physiology and Biophysics, University of Nebraska Medical Center, Omaha, Nebraska 68198-4575
![]() |
ABSTRACT |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
Protein kinase C (PKC) plays an
important role in activating store-operated Ca2+ channels
(SOC) in human mesangial cells (MC). The present study was performed to
determine the specific isoform(s) of conventional PKC involved in
activating SOC in MC. Fura 2 fluorescence ratiometry showed that the
thapsigargin-induced Ca2+ entry (equivalent to SOC) was
significantly inhibited by 1 µM Gö-6976 (a specific PKC and
I inhibitor) and PKC
antisense treatment (2.5 nM for 24-48
h). However, LY-379196 (PKC
inhibitor) and
2,2',3,3',4,4'-hexahydroxy-1,1'-biphenyl-6,6'-dimethanoldimethyl ether
(HBDDE; PKC
and
inhibitor) failed to affect thapsigargin-evoked activation of SOC. Single-channel analysis in the cell-attached configuration revealed that Gö-6976 and PKC
antisense
significantly depressed thapsigargin-induced activation of SOC.
However, LY-379196 and HBDDE did not affect the SOC responses. In
inside-out patches, application of purified PKC
or
I, but not
II or
, significantly rescued SOC from postexcision rundown.
Western blot analysis revealed that thapsigargin evoked a decrease in
cytosolic expression with a corresponding increase in membrane
expression of PKC
and
. However, the translocation from cytosol
to membranes was not detected for PKC
I or
II. These results
suggest that PKC
participates in the intracellular signaling pathway
for activating SOC upon release of intracellular stores of
Ca2+.
thapsigargin; patch clamp; fura 2 fluorescence
![]() |
INTRODUCTION |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
STORE-OPERATED CA2+ channels (SOC), identified in a variety of excitable and nonexcitable cells, have multiple physiological functions that include participating in proliferation, immunoreaction, muscle contraction, and secretion (10, 11, 22, 30, 41, 52). In human glomerular mesangial cells (MC), SOC have been described using both electrophysiological and fura 2 techniques (28, 31, 33). MC are specialized renal cells that surround glomerular capillaries and regulate filtration rate by contracting or relaxing in response to agents like angiotensin II or nitric oxide (32, 44).
Protein kinase C (PKC) is composed of a family of related isoenzymes,
grouped into three major classes of conventional
Ca2+-dependent PKCs (,
I,
II, and
), novel
Ca2+-independent PKCs (
,
,
, and
), and
atypical Ca2+-and lipid-independent PKCs (
,
, µ,
and
) (6, 35, 36). All isoforms express distinct
enzymological properties, differential tissue distribution, different
substrate specificity, and specific subcellular localization with
distinct modes of cellular regulation (4, 6, 9, 18, 23, 36,
38). For example, PKC
,
,
, and
, but not PKC
,
which is strongly expressed in cardiomycytes, were detected in rat MC
as determined by Western blotting (18, 19, 42). In renal
epithelial cells, PKC
,
, and
are all localized in the
cytoskeletal compartment; however, only PKC
and
are able to
translocate from the cytosol to membranes on activation by the phorbol
ester 12-O-tetradecanoylphorbol 13-acetate (TPA; Refs.
4 and 34). Moreover, PKC
is a positive mediator of
vascular smooth muscle proliferation (37), whereas
PKC
II is inhibitory (50). Whereas PKC
promotes cell
growth in vascular smooth muscle, PKC
depresses proliferation of a
human colonic adenocarcinoma cell line (43). These
differences in structure, enzymatic properties, and intracellular
localization illustrate that each of the PKC isoforms possess specific
cellular functions.
Previous studies from this laboratory have demonstrated that PKC
mediates epidermal growth factor and thapsigargin-induced activation of
SOC via a phosphorylation mechanism, measured by fura 2 fluorescence
and patch clamping (26, 27). The present study was
performed to determine which specific isoform of PKC is the
intermediary messenger in this signaling pathway. Fura 2 fluorescence
and conventional patch clamping were combined with biochemical
approaches to examine the involvement of the classic isoforms PKC ,
I,
II, and
. Because obtaining whole cell currents is
technically difficult in MC, single-channel current recordings and
whole cell Ca2+ measurements with fluorescent dyes were
employed in the present study.
![]() |
EXPERIMENTAL PROCEDURES |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
Preparation of Cultures of MC
The details regarding the procedures and methods for culturing MC were described in a previous study (13). Briefly, MC were purchased from Biowhittaker (Walkersville, MD) and cultured in Dulbecco's modified Eagle's medium (DMEM; Sigma Chemical, St. Louis, MO) supplemented with 10 mM N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid (HEPES), 2.0 mM glutamine, 0.66 U/ml insulin, 1.0 mM sodium pyruvate, 0.1 mM nonessential amino acids, 100 U/ml penicillin, 100 µg/ml streptomycin, and 20% fetal bovine serum (pH 7.2-7.4). Only subpassages of MCMeasurement of [Ca2+]i
The intracellular Ca2+ concentration [Ca2+]i was monitored in MC using fura 2 and dual excitation wavelength fluorescence microscopy, as previously described (3, 12). In brief, MC were incubated with physiological saline solution containing 7 µM fura 2-AM, 0.09 g/dl DMSO, and 0.018 g/dl Pluronic F-127 (Molecular Probes, Eugene, OR) for 60 min at 23°C. A selected individual cell was illuminated alternately at excitation wavelengths of 340 and 380 nm (bandwidth = 3 nm) provided by a DeltaScan dual monochromator system (Photon Technology International, Monmouth Junction, NJ). The emission wavelength was 510 nm. Background-corrected data were collected at a rate of 5 points/s, stored, and analyzed using the FeliX software package (Photon Technologies). Calibration of the fura 2 signal was performed according to established methods previously described (3, 12).Patch-Clamp Procedures
Conventional cell-attached and inside-out patch configurations were used in the present study. Glass pipettes (plain; Fisher Scientific, Pittsburgh, PA) were prepared with a pipette puller and polisher (PP-830 and MF-830, respectively; Narishige, Tokyo, Japan). The internal diameter of the pipette tip was ~0.5 µm.Single-channel currents were recorded and analyzed using standard
patch-clamp techniques (13, 14). The patch pipette, partially filled with 90 mM BaCl2 solution, was in contact
with a Ag-AgCl wire on a polycarbonate holder connected to the head stage of the patch clamp (PC-501A; Warner Instrument, Hamden, CT). The
pipettes were lowered onto the cell membrane and suction was applied to
obtain a high resistance (>10 G) seal. All experiments were
conducted at room temperature (22-23°C). Data were digitized for
single-channel analysis using an analog-to-digital interface (Axon
Instruments, Foster City, CA) and recorded by a computer system.
Low-pass filter was set at 500 Hz.
Single-Channel Analysis
The unitary current (i), defined as zero for the closed state (C), was determined as the mean of the best-fit Gaussian distribution of the amplitude histograms. Channels were considered open (O) when the total current (I) was >(nWestern Blot Analysis
When cell monolayers, grown in 150-ml flasks, were 80% confluent, the medium was replaced by serum-free DMEM. After 24 h, the medium was replaced by fresh serum-free DMEM with or without thapsigargin (1 µM for 3-5 min). Cells were scraped in PBS with the appropriate amount of protein kinase inhibitor. After centrifuging the cell suspension at 500 g for 10 min at 4°C, the cell pellets were sonicated five times for 10 s each in 180 µl of PBS plus 20 µl of protein kinase inhibitor. The membrane and cytosolic fraction were isolated by centrifugation at 100,000 g for 30 min at 4°C. The membrane pellet was solubilized in a lysis buffer. Equal amounts of proteins, quantified using the Bio-Rad protein assay, were loaded to the 12% SDS-PAGE gel. The proteins were then transferred to the nitrocellulose membrane. The membranes were probed with primary rabbit or mouse monoclonal or polyclonal antibodies (depending on the isoform of PKC) specific for a classic PKC isoform at an appropriate dilution (1:50). A horseradish peroxidase-labeled goat anti-rabbit or anti-mouse IgG secondary antibody was then used to react with PKC antibodies at 1:50,000 dilution. The immunoblots were labeled by enhanced chemiluminescent (ECL) reagents and then placed against reflection autoradiography film and developed in a Kodak M35A X-OMAT processor. The isoforms of PKC in cytosolic and membrane fractions were quantified by measuring densitometry of specific bands using Quantity One 4.1 software. In each group, the total optical densities of a PKC isoform in the cytosolic and membrane fractions were counted as 100%. The amount of individual isoform in either fraction was expressed as a percentage of the total optical density.PKC Antisense Oligonucleotide Treatment
Solutions and Chemicals
For all fura 2 and cell-attached patch experiments, the initial extracellular physiological saline solution (PSS) contained (in mM): 135 NaCl, 5 KCl, 10 HEPES, 2 MgCl2, and 1 CaCl2. For inside-out patches, the bathing solution contained (in mM): 140 KCl, 2 MgCl2, 0.001 CaCl2, and 10 HEPES. The pipette solution for all patch experiments contained 90 mM BaCl2 plus 10 mM HEPES. In fura 2 experiments, the free Ca2+ concentration of the bath was adjusted to <10 nM by buffering PSS with 1.08 mM EGTA, according to the calcium concentration program by MTK Software. The pH in all solutions was adjusted to 7.4. Thapsigargin, Gö-6976, 2,2',3,3',4,4'-hexahydroxy-1,1'-biphenyl-6,6'-dimethanol dimethyl ether (HBDDE), purified PKCStatistical Analysis
In patch-clamp experiments, all NPo values were calculated from at least 10 s of single-channel recording. Comparisons between two individual groups were performed by using a Student t-test. One-way ANOVA followed by Student-Newman-Keuls tests were used for comparisons among multiple groups. Data are reported as means ± SE; n is the number of cells. Significance was P < 0.05. Statistical analysis was performed using SigmaStat (Jandel Scientific, San Rafael, CA). ![]() |
RESULTS |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
Fura 2 Experiments
Effects of specific PKC isoform inhibitors on thapsigargin-induced
capacitative Ca2+ entry.
Thapsigargin, a specific inhibitor of the sarcoplasmic reticulum
Ca2+-ATPase (SERCA) (45), has been used as an
efficient tool to specifically activate SOC in a variety of cell types
(40). Using fura 2 fluorescence ratiometry, the
[Ca2+]i response to thapsigargin was
monitored in the absence or presence of specific inhibitors to classic
PKC isoforms. Figure 1A shows a typical profile of the change in [Ca2+]i
induced by thapsigargin and subsequent manipulation of bath calcium
concentration ([Ca2+]o). Application of 1 µM thapsigargin in the presence of 1 mM [Ca2+]o evoked a rapid increase in
[Ca2+]i to 180 nM, followed by a plateau
phase of ~80 nM. On reduction of bath Ca2+ to <10 nM,
the [Ca2+]i was lowered from the sustained
stage to ~10 nM. Subsequent readmission of 1 mM Ca2+ to
the bath induced an immediate increase in
[Ca2+]i to 185 nM. This incremental change in
[Ca2+]i in response to readmission of
Ca2+, defined as [Ca2+]i in
the present study, is an indicator of Ca2+ entering the
cell through SOC (28) and is equivalent to capacitative Ca2+ entry as depicted by Putney and McKay
(41). Thus, in the following experiments using
fura 2 ratiometry, we focused on the alteration in
[Ca2+]i induced by treatment of specific
inhibitors of PKC isoforms.
|
Effects of PKC antisense on thapsigargin-induced capacitative
Ca2+ entry.
The near complete abolishment of
[Ca2+]i
by Gö-6976 indicated that PKC
might be a specific mediator of
capacitative Ca2+ entry. To further explore this notion,
the thapsigargin-evoked rise in [Ca2+]i was
examined in cells treated with PKC
antisense and scrambled oligonucleotides. As shown in Fig. 2,
pretreatment with PKC
antisense (2.5 nM) for 1-2 days greatly
depressed
[Ca2+]i. However, when MC were
treated for 1-2 days with the same dose of scrambled nonsense
oligonucleotides,
[Ca2+]i was not
different from control (82.7 ± 16.8 nM vs. 113.9 ± 23.1 nM,
scrambled sequence vs. control, P > 0.05; Fig.
2B).
|
Patch-Clamp Experiments
Effects of various PKC isoform inhibitors on thapsigargin-induced
activation of SOC in cell-attached patches.
The cell-attached configuration was employed to detect single-channel
currents of SOC responding to thapsigargin in the presence and absence
of specific inhibitors of PKC isoforms. Representative tracings of
single channel currents are shown in Fig. 3A. Consistent with previous reports (26, 28), SOC have minimal
spontaneous activity in basal conditions (NPo:
0.17). Depletion of internal Ca2+ stores by thapsigargin
increased the NPo to 0.26. The
thapsigargin-induced response was ablated in the presence of
Gö-6976 (Fig. 3, A and B). However, neither LY-379196
nor HBDDE attenuated the currents activated by thapsigargin (Fig. 3,
A and B). None of the three inhibitors
significantly affected the basal activity of SOC (Fig. 3A).
|
Effects of PKC antisense on SOC in cell-attached patches.
The role of PKC
in the SOC signaling pathway was examined by
pretreating MC with PKC
antisense or scrambled nonsense
oligonucleotides before detecting the thapsigargin-evoked SOC
responses. As shown in Fig. 4, in the
presence of the scrambled nonsense sequence, application of
thapsigargin still evoked a significant increase in open probability of
SOC (by 98.3 ± 33.5%). However, in the group treated with PKC
antisense, thapsigargin evoked only a slight increase in
NPo (by 9.5 ± 3.3%). No significant
difference in basal activity of SOC was detected when comparing the
scrambled sequence and antisense-treated groups
(NPo: 0.26 ± 0.09 vs. 0.25 ± 0.09).
|
Effects of purified PKC isoforms on SOC in inside-out patches.
The inside-out configuration was employed to determine the effects of
four classic purified isoforms of PKC on the single-channel SOC
currents. In these experiments, as reported previously
(26), a spontaneous decrease in SOC activity (rundown) was
routinely observed after excision. When the channel activity obtained
stability after excision, the specific PKC isoform was added to the
bath. Because the classic PKCs require phospholipid and
Ca2+ to be activated, 1 µM PMA, 100 µM Mg-ATP, and 1 mM
Ca2+ were added to the solution with each PKC isoform. A
previous study demonstrated that 1 mM Ca2+ or 100 µM
Mg-ATP in the bath did not affect SOC activity (26). The
data from this series of experiments are summarized in Fig. 5. Among the four classic isoforms,
PKC and
I reactivated SOC from postexcision rundown, whereas
PKC
II and
failed to restore channel activity. The restoration of
SOC activity by PKC
and
I cannot be attributed to PMA because
this stimulatory effect was not observed for PKC
II and
under the
same conditions.
|
Western blot analysis of expression of PKC,
I,
II, and
in cytosol and membrane fractions.
The Ca2+ imaging and patch-lamp experiments suggested that
PKC
is a contributor to thapsigargin-induced activation of SOC. Results from inside-out patches suggested that SOC are activated by
PKC
as well as
I. Western blotting was used to determine which
PKC isoforms are present endogenously in MC and involved in activating
SOC. Because PKC translocates from cytosol to its substrate when
activated, it is presumed that the candidate isoform of PKC would
respond to thapsigargin with increased expression in the membranes
where SOC are located. The representative immunoblotting bands for each
isoform and averaged data for control and various treatments are shown
in Fig. 6. All four classic PKC isoforms were detected in the cultured MC. In the absence of thapsigargin, PKC
and
were approximately evenly distributed within the
cytosolic and membrane fractions. PKC
I was predominately present in
the cytosol, whereas PKC
II was primarily in the membrane fraction. In the samples pretreated with 1 µM thapsigargin for 3-5 min, the immunoblotting bands specific for PKC
and
were reduced in
the cytosol and more intense in the membrane fractions, indicating migration of PKC
and
from the cytosol to the membranes. As a
positive control, the samples were pretreated with 1 µM PMA, a strong
activator of PKC. As shown in Fig. 6, a similar alteration in
distribution of PKC
and
isoforms was observed. However, PKC
I
was not translocated with thapsigargin treatment, even though its
translocation was obtained with PMA treatment. Because PKC
II was
already nearly 100% in the membrane fraction, thapsigargin-induced translocation could not be observed for this isoform.
|
Expression of PKC under treatment with PKC
-blocking peptide
or PKC
antisense.
Analysis with fura 2 fluorescence ratiometry, patch clamping, and
Western blotting consistently implicated PKC
as a mediator in the
activation of SOC by thapsigargin. To further investigate the notion
that thapsigargin treatment triggers PKC
translocation, PKC
antibody was preincubated with specific PKC
blocking peptide for
1 h before its addition to the nitrocellulose membrane, which had
been transferred with PKC
proteins. The immunoblotting bands, present in the cytosolic and membrane compartments of MC, were not
detected after preabsorption of PKC
antibody, indicating the
specificity of the PKC
protein detected in the present study.
|
![]() |
DISCUSSION |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
Depending on the specifically tested cells and the experimental
conditions, variable results have been reported on the modulation of
SOC by PKC (1, 2, 7, 39, 46, 51). The differential tissue
distribution, intracellular localization, and cellular functions of
different isoforms of PKC might also contribute to these discrepancies.
Using fura 2 fluorescence measurements combined with patch clamping, we
previously demonstrated that PKC activates SOC through a
phosphorylation mechanism (26). The previous findings are
extended by the current study, which detects specific isoforms of PKC
involved in this signaling pathway. The data of the present study
showed the following: 1) Gö-6976, a PKC and
I
inhibitor, significantly attenuated thapsigargin-induced capacitative
Ca2+ entry measured by fura 2 fluorescence and
single-channel analysis; 2) purified PKC
and
I, but
not PKC
II and
, reactivated SOC from postexcision rundown;
3) specific PKC
antisense depressed Ca2+
influx stimulated by thapsigargin; and 4)
thapsigargin-induced depletion of internal Ca2+ stores
triggered translocation of PKC
and
, but not
I and
II, from
the cytosolic to membrane cellular fractions. These results indicate
that PKC
plays an important role in regulating activity of SOC.
Influences of selective inhibitors of various PKC isoforms.
Within a restricted concentration range, a selective inhibitor of a
specific PKC isoform might still affect another isoform to some extent.
This problem must be considered when interpreting results utilizing
pharmacological tools. In the present study, 1 µM Gö-6976, an
inhibitor of both PKC and
I, significantly depressed the
thapsigargin-induced capacitative Ca2+ entry assessed by
Ca2+ imaging (Fig. 1). This inhibition was corroborated
with electrophysiological methods (Fig. 3), implying that either PKC
or
I (or both) mediate the thapsigargin-evoked activation of SOC.
Interestingly, inhibiting PKC
and
by HBDDE or PKC
I and
II
by LY-379196 failed to suppress the thapsigargin-induced responses.
These results could be explained by opposing effects of PKC
II or
with PKC
I and
on SOC, respectively. Thus the stimulatory effects
from PKC
or
I were compromised by the inhibitory effects from
PKC
or
II. Indeed, opposite effects of different isoforms of PKC
on the same cellular events have been reported by many groups of
investigators (5, 37, 50). The data from inside-out
patches further suggested that PKC
and
I are able to activate SOC
directly (Fig. 5). However, the possible inhibitory effects of PKC
II
and
could not be detected with the inside out configuration because
the channel activity had already been minimized after excision.
Identification PKC as a mediator for thapsigargin-induced
activation of SOC.
When activated, PKC normally translocates to its target site, which, in
the case of SOC, is located in the plasma membrane. The results of
Western blotting revealed that only PKC
and
translocated from
cytosol to membranes in response to thapsigargin (Fig. 6). However,
this trafficking could not be observed for PKC
I and
II. These
experiments suggest that PKC
and
are part of the signaling
pathway involving the activation of SOC after depleting internal
Ca2+ stores.
![]() |
ACKNOWLEDGEMENTS |
---|
This work was supported by National Institute of Diabetes and Digestive and Kidney Diseases Grant DK-49561 (to S. C. Sansom), a fellowship grant from American Heart Association (Heartland Affiliate) (to R. Ma), and National Heart, Lung, and Blood Institute Research Training Grant 1T32-HL-07888 (to P. Kudlacek).
![]() |
FOOTNOTES |
---|
Address for reprint requests and other correspondence: S. C. Sansom, Dept. of Physiology and Biophysics, Univ. of Nebraska Medical Center, 984575 Nebraska Medical Center, Omaha, NE 68198-4575 (E-mail: ssansom{at}unmc.edu).
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.
July 24, 2002;10.1152/ajpcell.00141.2002
Received 14 June 2002; accepted in final form 24 June 2002.
![]() |
REFERENCES |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
1.
Bode, HP,
and
Göke B.
Protein kinase C activates capacitative calcium entry in the insulin secreting cell line RINm5F.
FEBS Lett
339:
307-311,
1994[ISI][Medline].
2.
Camello, C,
Pariente JA,
Salido GM,
and
Camello PJ.
Sequential activation of different Ca2+ entry pathways upon cholinergic stimulation in mouse pancreatic acinar cells.
J Physiol
516:
399-408,
1999
3.
Carmines, PK,
Fowler BC,
and
Bell PD.
Segmentally distinct effects of depolarization on intracellular [Ca2+] in renal arterioles.
Am J Physiol Renal Fluid Electrolyte Physiol
265:
F677-F685,
1993
4.
Clarke, H,
Ginanni N,
Soler AP,
and
Mullin JM.
Regulation of protein kinase C- and -
isoforms by phorbol ester treatment of LLC-PK1 renal epithelia.
Kidney Int
58:
1004-1015,
2000[ISI][Medline].
5.
Condorelli, G,
Vigliotta G,
Trencia A,
Maitan MA,
Caruso M,
Miele C,
Oriente F,
Santopietro S,
Formisano P,
and
Beguinot F.
Protein kinase C (PKC)- activation inhibits PKC-
and mediates the action of PED/PEA-15 on glucose transport in the L6 skeletal muscle cells.
Diabetes
50:
1244-1252,
2001
6.
Dekker, LV,
and
Parker PJ.
Protein kinase C-a question of specificity.
Trends Biochem Sci
19:
73-77,
1994[ISI][Medline].
7.
Dellis, O,
Gangloff SC,
Paulais M,
Tondelier D,
Rona JP,
Brouillard F,
Bouteau F,
Guenounou M,
and
Teulon J.
Inhibition of the calcium release-activated calcium (CRAC) current in Jurkat T cells by the HIV-1 envelope protein gp160.
J Biol Chem
277:
6044-6050,
2002
8.
Dev, KK,
Nishimune A,
Henley JM,
and
Nakanishi S.
The protein kinase C binding protein PICK1 interacts with short but not long form alternative splice variants of AMPA receptor subunits.
Neuropharmacology
38:
635-644,
1999[ISI][Medline].
9.
Erdbrügger, W,
Keffel J,
Knocks M,
Otto T,
Philipp T,
and
Michel MC.
Protein kinase C isoenzymes in rat and human cardiovascular tissues.
Br J Pharmacol
120:
177-186,
1997[Abstract].
10.
Gibson, A,
Mcfadzean I,
Wallace P,
and
Wayman CP.
Capacitative Ca2+ entry and the regulation of smooth muscle tone.
Trends Pharmacol Sci
19:
266-269,
1998[ISI][Medline].
11.
Golovina, VA,
Platoshyn O,
and
Bailey CL.
Upregulated TRP and enhanced capacitative Ca2+ entry in human pulmonary artery myocytes during proliferation.
Am J Physiol Heart Circ Physiol
280:
H746-H755,
2001
12.
Grynkiewicz, G,
Poenie M,
and
Tsien RY.
A new generation of Ca2+ indicators with greatly improved fluorescence properties.
J Biol Chem
260:
3440-3450,
1985[Abstract].
13.
Hall, D,
Carmines PK,
and
Sansom SC.
Dihydropyridine-sensitive Ca2+ channels in human glomerular mesangial cells.
Am J Physiol Renal Physiol
278:
F97-F103,
2000
14.
Hamill, OP,
Marty A,
Neher E,
Sackmann B,
and
Sifworth F.
Improved patch-clamp techniques for high resolution current recording from cells and cell-free membrane patches.
Pflügers Arch
391:
85-100,
1981[ISI][Medline].
15.
Hofmann, T,
Obukhov AG,
Schaefer M,
Harteneck C,
Gudermann T,
and
Schultz G.
Direct activation of human TRPC6 and TRPC3 channels by diacylglycerol.
Nature
397:
259-263,
1999[ISI][Medline].
16.
Hoth, M,
and
Penner R.
Calcium release-activated calcium current in rat mast cells.
J Physiol
465:
359-386,
1993[Abstract].
17.
Huber, A,
Sander P,
Gobert A,
Bähner M,
Hermann R,
and
Paulsen R.
The transient receptor potential (Trp), a putative store-operated Ca2+ channel essential for phosphoinositide-mediated photoreception, forms a signaling complex with NorpA, InaC and InaD.
EMBO J
15:
7036-7045,
1996[Abstract].
18.
Huwiler, A,
Fabbro D,
and
Pfeilschifter J.
Possible regulatory functions of protein kinase C- and -
isoenzymes in rat renal mesangial cells.
Biochem J
279:
441-445,
1991[ISI][Medline].
19.
Kikkawwa, R,
Haneda M,
Uzu T,
Koya D,
Sugimoto T,
and
Shigeta Y.
Translocation of protein kinase C and
in rat glomerular mesangial cells cultured under high glucose conditions.
Diabetologia
37:
838-841,
1994[ISI][Medline].
20.
Klauck, TM,
Faux MC,
Labudda K,
Langeberg LK,
Jaken S,
and
Scott JD.
Coordination of three signaling enzymes by AKAP79, a mammalian scaffold protein.
Science
271:
1589-1592,
1996[Abstract].
21.
Koehler, JA,
and
Moran MF.
RACK1, a protein kinase C scaffolding protein, interacts with the PH domain of p120GAP.
Biochem Biophys Res Commun
283:
888-895,
2001[ISI][Medline].
22.
Kurebayashi, N,
and
Ogawa Y.
Depletion of Ca2+ in the sarcoplasmic reticulum stimulates Ca 2+ entry into mouse skeletal muscle fibers.
J Physiol
533:
185-199,
2001
23.
La Porta, CAM,
and
Comolli R.
Biochemical and immunological characterization of calcium-dependent and -independent PKC isoenzymes in renal ischemia.
Biochem Biophys Res Commun
191:
1124-1130,
1993[ISI][Medline].
24.
Leinweber, B,
Parissenti AM,
Gallant C,
Gangopadhyay SS,
Kirwan-Rhude A,
Leavis PC,
and
Morgan KG.
Regulation of protein kinase C by the cytoskeletal protein calponin.
J Biol Chem
275:
40329-40336,
2000
25.
Lim, YB,
Kang SS,
Park TK,
Lee YS,
Chun JS,
and
Sonn JK.
Disruption of actin cytoskeleton induces chondrogenesis of mesenchymal cells by activation protein kinase C- signaling.
Biochem Biophys Res Commun
273:
609-613,
2000[ISI][Medline].
26.
Ma, R,
Pluznick J,
Kudlacek P,
and
Sansom SC.
Protein kinase C activates store-operated Ca2+ channels in human glomerular mesangial cells.
J Biol Chem
276:
25759-25765,
2001
27.
Ma, R,
and
Sansom SC.
Epidermal growth factor activates store-operated calcium channels in human glomerular mesangial cells.
J Am Soc Nephrol
12:
47-53,
2001
28.
Ma, R,
Smith S,
Child A,
Carmines PK,
and
Sansom SC.
Store-operated Ca2+ channels in human glomerular mesangial cells.
Am J Physiol Renal Physiol
278:
F954-F961,
2000
29.
Maasch, C,
Wagner S,
Lindschau C,
Alexander G,
Buchner K,
Gollasch M,
Luft FC,
and
Haller H.
Protein kinase C targeting is regulated by temporal and spatial changes in intracellular free calcium concentration [Ca2+]i.
FASEB J
14:
1653-1663,
2000
30.
McDaniel, SS,
Platoshyn O,
and
Wang J.
Capacitative Ca2+ entry in agonist-induced pulmonary vasoconstriction.
Am J Physiol Lung Cell Mol Physiol
280:
L870-L880,
2001
31.
Menè, P,
Pugliese F,
and
Cinotti GA.
Regulation of capacitative calcium influx in cultured human mesangial cells: roles of protein kinase C and calmodulin.
J Am Soc Nephrol
7:
983-990,
1996[Abstract].
32.
Menè, P,
Simonson MS,
and
Dunn MJ.
Physiology of mesangial cell.
Physiol Rev
69:
1347-1424,
1989
33.
Menè, P,
Teti A,
Pugliese F,
and
Cinotti GA.
Calcium release-activated calcium influx in cultured human mesangial cells.
Kidney Int
46:
122-128,
1994[ISI][Medline].
34.
Mullin, JM,
Soler AP,
Laughlin KV,
Kampherstein JA,
Russo LM,
Saladik DT,
George K,
Shurina RD,
and
O'Brien TG.
Chronic exposure of LLC-PK1 epithelia to the phorbol ester TPA produces polyp-like foci with leaky tight junctions and altered protein kinase C- expression and localization.
Exp Cell Res
227:
12-22,
1996[ISI][Medline].
35.
Newton, AC.
Protein kinase C: structure AC, function, and regulation.
J Biol Chem
270:
28495-28498,
1995
36.
Nishizuka, Y.
Intracellular signalling by hydrolysis of phospholipids and activation of protein kinase C.
Science
258:
607-614,
1992[ISI][Medline].
37.
Okazaki, J,
Mawatari K,
Liu B,
and
Kent KC.
The effect of protein kinase C and its subtype on human vascular smooth muscle cell proliferation, migration and fibronectin production.
Surgery
128:
192-197,
2000[ISI][Medline].
38.
Östlund, E,
Mendez CF,
Jacobson G,
Fryckstedt J,
Meister B,
and
Aperia A.
Expression of protein kinase C isoforms in renal tissue.
Kidney Int
47:
766-773,
1995[ISI][Medline].
39.
Parekh, AB,
and
Penner R.
Depletion-activated calcium current is inhibited by protein kinase in RBL-2H3 cells.
Proc Natl Acad Sci USA
92:
7907-7911,
1995[Abstract].
40.
Peterson, CC,
and
Berridge MJ.
The regulation of capacitative calcium entry by calcium and protein kinase C in Xenopus oocytes.
J Biol Chem
269:
32246-32253,
1994
41.
Putney, JW, Jr,
and
McKay RR.
Capacitative calcium entry channels.
Bioessays
21:
38-46,
1999[ISI][Medline].
42.
Roman, BB,
Geenen DL,
Leitges M,
and
Buttrick PM.
PKC- is not necessary for cardiac hypertrophy.
Am J Physiol Heart Circ Physiol
280:
H2264-H2270,
2001
43.
Scaglione-Sewell, B,
Abraham C,
Bissonnette M,
Skarosi SF,
Hart J,
Davidson NO,
Wali RK,
Davis BH,
Sitrin M,
and
Brasitus TA.
Decreased PKC- expression increases cellular proliferation, decreases differentiation, and enhances the transformed phenotype of CaCo-2 cells.
Cancer Res
58:
1074-1081,
1998[Abstract].
44.
Stockand, JD,
and
Sansom SC.
Glomerular mesangial cells: electrophysiology and regulation of contraction.
Physiol Rev
78:
723-744,
1998
45.
Thastrup, O,
Cullen PJ,
Drøbak BK,
Hanley MR,
and
Dawson AP.
Thapsigargin, a tumor promoter, discharges intracellular Ca2+ stores by specific inhibition of the endoplasmic reticulum Ca2+-ATPase.
Proc Natl Acad Sci USA
87:
2466-2470,
1990[Abstract].
46.
Törnquist, K.
Modulatory effect of protein kinase C on thapsigargin-induced calcium entry in thyroid FRTL-5 cells.
Biochem J
290:
443-447,
1993[ISI][Medline].
47.
Vallentin, A,
Lo TC,
and
Joubert D.
A single point mutation in the V3 region affects protein kinase C targeting and accumulation at cell-cell contacts.
Mol Cell Biol
21:
3351-3363,
2001
48.
Vazquez, G,
Lievremont JP,
and
Putney JW, Jr.
Human Trp3 forms both inositol trisphosphate receptor-dependent and receptor-independent store-operated cation channels in DT40 avian B lymphocytes.
Proc Natl Acad Sci USA
98:
11777-11782,
2001
49.
Venkatachalam, K,
Ma HT,
Ford DL,
and
Gill DL.
Expression of functional receptor-coupled TRPC3 channels in DT40 triple receptor InsP3 knockout cells.
J Biol Chem
276:
33980-33985,
2001
50.
Yamamoto, M,
Acevedo-duncan M,
Chalfant CE,
Patel NA,
Watson JE,
and
Cooper DR.
Acute glucose-induced downregulation of PKC-II accelerates cultured VSMC proliferation.
Am J Physiol Cell Physiol
279:
C587-C595,
2000
51.
Yao, Y,
and
Tsien RY.
Calcium current activated by depletion of calcium stores in Xenopus oocytes.
J Gen Physiol
109:
703-715,
1997
52.
Zweifach, A,
and
Lewis RS.
Mitogen-regulated Ca2+ current of T lymphocytes is activated by depletion of intracellular Ca2+ stores.
Proc Natl Acad Sci USA
90:
6295-6299,
1993[Abstract].