From the Department of Pharmacology, University of Washington,
Seattle, Washington 98195-7280
Received for publication, July 27, 2000, and in revised form, October 16, 2000
Olfactory sensory neurons (OSNs) respond acutely
to volatile molecules and exhibit adaptive responses including
desensitization to odorant exposure. Although mechanisms for short term
adaptation have been described, there is little evidence that odorants
cause long lasting, transcription-dependent changes in
OSNs. Here we report that odorants stimulate cAMP-response element
(CRE)-mediated transcription in OSNs through Ca2+
activation of the ERK/MAPK/p90rsk pathway. Odorant stimulation
of ERK phosphorylation was ablated by inhibition of
calmodulin-dependent protein kinase II suggesting that
odorant activation of ERK is mediated through this kinase. Moreover, a
brief exposure in vivo to an odorant in vapor phase stimulated CRE-mediated gene transcription in discrete populations of
OSNs. These data suggest that like central nervous system neurons, OSNs
may undergo long term adaptive changes mediated through CRE-mediated transcription.
 |
INTRODUCTION |
Genes encoding odorant receptors compose an estimated 1% of the
genome, reflecting the ancient and primal nature of olfaction. The
relative abundance of these genes also explains how animals can
discriminate among the innumerable combinations of odorous compounds
present in the environment (1, 3). Odorant receptors have distinct but
overlapping affinities for odorants and exhibit a semi-organized
pattern of expression in the convoluted topography of the olfactory
epithelium (4, 5). These features of the sensory apparatus suggest that
the initial encoding of odorant features is combinatorial, integrating
spatio-temporal differences in receptor activation throughout the
epithelium as well as differences in odorant concentration (6).
Although each of the perhaps ~1000 individual odorant receptors has
unique specificity for ligand binding, most if not all olfactory
signaling is mediated through cAMP (7-10). Odorant receptor activation
increases intracellular cAMP via an interaction with Golf
or Gs and adenylyl cyclase activation. This leads to
opening of the cyclic nucleotide-gated
(CNG)1 ion channel, membrane
depolarization, and the generation of action potentials (11). In
support of this model, disruption of the genes for Golf
(12), type III adenylyl cyclase (AC3) (13), or CNG (14) in mice ablates
electro-olfactogram responses to odorants in the olfactory epithelium.
Furthermore, AC3 mutant mice fail several odorant-based behavioral
tests indicating that adenylyl cyclase and cAMP signaling are critical
for olfactory-dependent behavior.
Activation of the CNG ion channel in OSNs causes a depolarization and a
transient increase in intracellular Ca2+ (15-17). This
Ca2+ signal, to the opposing effect, can lead to activation
of Ca2+/CaM-activated phosphodiesterase PDE1C2 (18) and
CaM-dependent protein kinase II (CaMKII) which
phosphorylates and inhibits AC3 (19-21). Therefore, CaMKII inhibition
of AC3 may contribute to termination of olfactory signaling. This idea
is supported by data showing that treatment of olfactory sensory
neurons with CaMKII inhibitors impairs odor adaptation (22). Other
kinases that contribute to modulation and desensitization of olfactory signaling include GRK-3 (23, 24), as well as cAMP-dependent protein kinase (PKA) and protein kinase C (PKC) (25). Thus rapid activation and inactivation of the cAMP signal are at the core of a
system developed for transient signaling to the olfactory bulb and
higher CNS where olfactory memories are thought to be stored.
There are several reports of sensitization of peripheral sensory
neurons to odorants at the step of primary detection. By using Pacific
Coho salmon, we demonstrated a preference for phenylethyl alcohol in
salmon that had been imprinted with the odorant as juveniles, and we
found that guanylyl cyclase activity in olfactory cilia isolated from
them was enhanced specifically in response to phenylethyl alcohol 2 years after exposure to the odorant (26). Furthermore, mice chronically
exposed to specific odorants develop an enhanced EOG signal in response
to these odorants (27). Cultured rat OSNs also show an enhanced cAMP
signal in response to the second of two odorant exposures (28). These
reports suggest the interesting possibility that olfactory sensory
neurons may exhibit some form of cellular memory, and they are not
simply conduits for transfer of olfactory information to the olfactory bulb.
Because of the well established role of the ERK/MAP kinase regulatory
system and CRE-mediated transcription for neuroplasticity in the CNS
(for general reviews see Refs. 29-31), we carried out experiments to
determine whether exposure to odorants activates these pathways using
cultured OSNs and a CRE/LacZ transgenic reporter mouse strain (32, 33).
We report the discovery of an unexpected signaling pathway intrinsic to
odorant stimulation of mammalian OSNs, providing evidence that this
sensory tissue may exhibit neuroplasticity akin to that of CNS neurons.
Our data indicate that a brief exposure to odorants activates ERK/MAP
kinase signaling and initiates CRE-mediated gene transcription.
 |
MATERIALS AND METHODS |
Primary Culture of Neonatal Rat Olfactory Sensory
Neurons--
Cultures of primary OSNs were prepared as described by
Ronnett et al. (28), with modifications. In brief, olfactory
turbinates from 20 to 30 rat pups at 1-2 days of age were removed by
dissection, minced, and subjected to mild enzymatic digestion with
rocking at 37 °C for 1 h. Subsequently, the tissue was passed
through nylon filters of sequentially smaller pore size (250, 50, and 10 µm), and cells were plated at an approximate density of 10 (10)
cells/ml on 12-well tissue culture plates that had been coated with 25 ng/ml mouse laminin (Life Technologies, Inc.). Cells were plated and
maintained in minimum essential medium containing D-valine (Life Technologies, Inc.), 10% dialyzed fetal bovine serum (Life Technologies, Inc.), 5% NuSerum (Becton Dickinson), and 10 µM Ara-C (Sigma). Experiments were typically performed at
day 5 in vitro to allow non-neuronal cells to be selected
from the culture.
Immunocytochemical Detection of Phospho-ERK I/II in Cultured
OSNs--
Cells were cultured as described above but were plated on
glass coverslips coated with 25 ng/ml mouse laminin. One hour prior to
stimulation, the culture medium was replaced with pre-warmed serum/growth factor-free minimum essential medium, D-valine
supplemented with 50 mM Hepes buffer, pH 7.4 (MEM-H). Cells were stimulated with either 5 µM
forskolin or 15 µM odorant (citralva, isoamyl acetate, or
ethyl vanillin) for 4 min, immediately after which cells were fixed in
5% paraformaldehyde. Immunodetection of phospho-ERK I/II was performed
using standard procedures with a rabbit anti-phospho-ERK I/II antibody
(New England Biolabs) at 1:500 dilution and a Texas Red mouse
anti-rabbit IgG antibody (Jackson Immunochemicals) at 1:500 dilution.
Images were captured on a Bio-Rad MRC laser scanning confocal microscope.
Western Blot Analysis of MEK, ERK I/II, p90rsk, and CREB
Phosphorylation--
Neurons were cultured and plated on 12-well
tissue culture plates as described above. After 1 h in minimum
essential medium, D-valine/Hepes, neurons were stimulated
with the indicated odorant at 15 or 20 µM A23187.
Inhibitors (U0126 and KN-62) were used at 10 µM for
1 h prior to stimulation. After odorant stimulation for the
indicated times, cells were harvested in sample buffer (40 mM Tris, pH 6.9, 2 mM EGTA, 10% glycerol, 1%
dithiothreitol, 1% SDS, 0.04% bromphenol blue), and extracts were
boiled for 10 min. Samples were subjected to 10% SDS-polyacrylamide
gel electrophoresis and transferred to nitrocellulose membranes, which
were then blocked in 10% milk in PBST. Membranes were incubated with
antibodies to the phosphorylated and activated forms of Raf, MEK, ERK
I/II, p90rsk, and CREB (New England Biolabs), each at 1:1000
dilution, and an antibody to ERK I/II (Santa Cruz Biotechnology) at
1:1000 to control for protein loading.
Electro-olfactogram Recordings--
EOG recordings were
performed as described previously (14), with minor changes. In brief,
mice 14-16 weeks old were sacrificed by decapitation, and heads were
bisected through the septum. Septal cartilage was peeled away to expose
the apical surface of the olfactory turbinates, from which recordings
were taken using an agar- and saline-filled glass microelectrode. The
EOG, basal potential minus apical potential, was taken in the open
circuit configuration, whereas odorants were applied to the epithelia
in 1-s puffs interspersed with a continuous stream of moisturized
oxygen. Traces were captured and digitized using a Digidata 1200A (Axon
Instruments) connected to a PC computer, low pass filtered at 30 Hz,
and sampled at 125 Hz. Inhibition of MEK was performed by removing the
skin, brain, and other superfluous tissue from the bisected heads and
incubating them for 90 min in oxygenated MEM-H containing either
50 mM U0126 or Me2SO vehicle.
Immunocytochemistry for
-Galactosidase--
CRE/LacZ
transgenic mice of age 14-16 weeks were placed individually into a
behavior chamber fitted with an odorant delivery nozzle. Air was passed
through the vapor phase of a 1 mM solution of citralva and
through the nozzle into the chamber. Mice were allowed 2 min to explore
the chamber before the odorant pump was activated and 2 min in the
presence of the odorant before being returned to their home cages in an
odorant-free fume hood. Animals were sacrificed by decapitation 7 h later to allow transgene expression, and the heads were fixed in 6%
formaldehyde in 0.1 M sodium phosphate buffer, pH 7.4. Tissue was decalcified overnight in 0.5 M EGTA, pH 8.0, cryoprotected in 20% sucrose, and frozen in Tissue-TEK/OCT (Miles).
Tissue sections were taken at 30-µm intervals on a cryostat and
mounted on microscope slides. Immunodetection of
-galactosidase was
performed as described previously with a rabbit
-galactosidase antibody (5'-3') at 1:500 dilution and an Alexa goat anti-rabbit IgG
antibody (Molecular Probes) at 1:500 dilution. Images were captured on
a Bio-Rad MRC laser scanning confocal microscope.
 |
RESULTS |
We examined the effect of odorants on ERK/MAP kinase activity
because odorants generate transient increases in cAMP and
Ca2+, both of which stimulate ERK activity in CNS neurons
and PC12 cells (34-37). OSNs were cultured under conditions designed
to minimize serum/growth factor-stimulated ERK/MAP kinase activity and
exposed to low concentrations of odorants. Immunocytochemical analysis
of cultured OSNs stimulated for 4 min with the odorant citralva
revealed robust activation of ERK/MAP kinase in a subpopulation of
neurons (Fig. 1a). Whereas
forskolin, a direct activator of adenylyl cyclases, stimulated ERK
phosphorylation in a majority of neurons (~85%) (Fig. 1,
a and b), citralva produced this effect in only
~38% of the neurons (Fig. 1, a and b). This
observation is consistent with the expression of only a subset of
odorant receptors in individual OSNs, yielding a heterogeneously
responsive population. The relatively high percentage of cells
activated by citralva is not unexpected; the citralva preparation used
is a mixture of odorants that stimulates multiple receptors in
olfactory cilia. For example, citralva stimulates CaMKII
phosphorylation of AC3 in 20-30% of cultured OSNs (21).

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Fig. 1.
Odorant stimulation of ERK/MAP kinase
phosphorylation in OSNs. a, cultured OSNs were given
either no stimulus (CTL), 4 min of exposure to 15 µM citralva (CIT), or 4 min of exposure to 10 µM forskolin (FSK) and were processed for
immunocytochemical detection of phospho-ERK/MAP kinase. Compared with
controls, citralva-stimulated cultures exhibit ~38% of cells
positive for phospho-ERK, whereas ~85% of forskolin-stimulated cells
showed a phospho-ERK signal. b, images are representative of
results obtained in three experiments, which were quantified by cell
counting. Bar graph shows cumulative data from
(a).
|
|
Since the kinetics for activation of ERK/MAP kinase were significantly
slower than odorant-stimulated increases in cAMP and Ca2+,
ERK activation may not play an important role in primary olfactory signaling. This question was addressed by examining the effects of a
MEK inhibitor on electro-olfactogram (EOG) responses stimulated by
odorants. The EOG is a measure of odorant-stimulated field potentials
generated by changes in ion conductance across the ciliary, dendritic,
and somatic membranes of OSNs in an intact olfactory epithelium (39).
Incubating isolated turbinates in oxygenated MEM-H containing
the MEK inhibitor, U0126 (40), 90 min before recording the EOG response
produced no significant perturbation of the amplitude or kinetics of
field potentials elicited by a single application of citralva (Fig.
3). The response to a train of odorant
puffs produced the same characteristic desensitizing response in
vehicle and U0126-treated turbinates, and responses to multiple, spaced
applications of odorant were also identical.
Since we were particularly interested in odorant stimulation of
downstream transcriptional events, we also monitored odorant activation
of p90rsk, a CREB kinase that is activated by ERK/MAP kinase.
In addition, CREB phosphorylation at its transactivation site, Ser-133
(41, 42), was also analyzed. Odorants stimulated activation of
p90rsk that persisted for at least 20 min (Fig.
4a). CREB phosphorylation was
also transiently increased by citralva, in accord with a previous report that also showed formation of elements of a transcriptional complex (Fig. 4b) (43). ERK activation and phosphorylation
of CREB were both inhibited by U0126, consistent with the notion that
odorants stimulate CREB phosphorylation through the
MEK/ERK/p90rsk pathway, one of the major pathways that mediates
Ca2+ stimulation of CREB phosphorylation in hippocampal
neurons and PC12 cells (37). Thus, odorants stimulate a robust
induction of ERK/MAP kinase signaling that leads to phosphorylation of
the transcription factor CREB.
In attempt to determine mechanisms linking odorant-stimulation to
activation of ERK/MAP kinase signaling in OSNs, we measured ERK
activation in the presence of several kinase inhibitors after 5 min of
odorant stimulation. Interestingly, pretreatment of OSNs with the
CaMKII inhibitor KN-62 markedly attenuated the induction of phospho-ERK
in response to citralva, ethyl vanillin, or the calcium ionophore
A23187 (Fig. 5). Inhibitors of other
protein kinases including PKA
((RP)-8-bromo-cAMPs,
(RP)-CPT-cAMPs), PKC (Gö 6983, chelerythrin), or PKG (KT5823) produced no discernible effect on
odorant-stimulated ERK I/II phosphorylation (data not shown). These
data suggest that Ca2+ increases caused by odorants
stimulate CaMKII, which in turn leads to activation of the ERK/MAP
kinase pathway. Odorant stimulation of ERK/MAP kinase in OSNs may be
due to CaMKII phosphorylation and inhibition of p135 SynGAP by CaMKII
(44). Thus, we may have identified another mechanism, in addition
to CaMKII inhibition of AC3, by which CaMKII contributes to adaptive
responses to odorants.
The kinetics of ERK I/II activation, phosphorylation of CREB, and lack
of acute effect of MEK inhibition on the EOG response suggested that
the target for odorant-stimulated ERK I/II activity may be enhanced
transcription. Given that odorants stimulated CREB phosphorylation and
Ca2+ stimulation of CRE-mediated transcription in CNS
neurons is mediated by the MEK/ERK/p90rsk pathway, we tested
the hypothesis that simple odorant exposure may stimulate this pathway
in OSNs. This was accomplished using a CRE/LacZ reporter mouse strain
we developed to monitor activation of CRE-mediated transcription by
various physiological stimuli (32, 33). CRE/LacZ mice were exposed to a
gentle stream of air carrying the vapor phase of a 1 mM
solution of the odorant citralva for 2 min. The olfactory epithelium
was then analyzed for CRE-mediated transcription by Western analysis
and immunocytochemistry for
-galactosidase expression. Compared with
animals that received no exogenous odorant exposure, the
citralva-exposed mice exhibited a substantial induction of transgene
expression by Western analysis (Fig.
6a), and ICC analysis revealed
that neurons immunopositive for
-galactosidase were restricted
predominantly to a layer of the epithelium located in zone four (Fig.
6b). Thus, a simple odorant stimulus is sufficient to lead
to a transcription event in OSN that has been implicated in the
enactment of long term changes and memory formation in CNS tissue but,
until now, was not known to occur in sensory tissue.
The concept that sensory tissue might have the ability to adapt to
specific, frequently encountered stimuli such that it is optimized for
subsequent detection makes intuitive sense. Chemosensation, evolutionarily ancient and essential to the survival of countless organisms, would seem particularly likely to possess such a capacity. Although OSNs exhibit rapid adaptive responses to odorants including desensitization (18, 24, 25, 45, 46), sensory structures such as OSNs
have been generally thought of as conductors of information, not
participating actively in its subsequent use. As such, reports of
longer lasting olfactory sensory neuron sensitizations are provocative
(26-28). However, there is currently little insight concerning
signaling mechanisms that might mediate long lasting changes in OSNs,
other than the initial cAMP and Ca2+ increases caused by
odorant stimulation.
We describe here the induction of the ERK/MAP kinase pathway in
mammalian OSNs in response to a variety of odorants, exposing a novel
component of their signaling properties that may have an important role
in olfaction. Pharmacological inhibition of CaMKII resulted in a
diminished ability of odorants to stimulate ERK I/II phosphorylation.
Furthermore, odorants stimulated ERK/MAP kinase-dependent
phosphorylation of CREB, suggesting the possibility that individual
OSNs link odorant detection to gene transcription from CRE-containing
promoters. However, CREB phosphorylation is necessary but not
sufficient for stimulation of CRE-mediated transcription (32, 47-49).
Consequently, it was critical to determine whether CRE-mediated
transcription is activated in OSNs when an animal is exposed to an
odorant. We discovered that brief exposure in vivo to an
odorant leads to region-specific CRE-mediated gene transcription in the
olfactory epithelium. Interestingly, genetic mutation of the Ras
homologue LET-60 Ras disrupts chemotaxis in Caenorhabditis
elegans, suggesting that ERK/MAP kinase may contribute to
olfactory detection in simpler organisms (50). In contrast to our study
with mice that demonstrated odorant stimulation of ERK/MAP kinase
maximally at 5 min, odorant stimulation of ERK/MAP kinase in C. elegans occurs within seconds. This suggests that the ERK/MAP
kinase pathway may play different roles in vertebrate and invertebrate olfaction.
Activation of the MAPK pathway in neurons occurs via differing
mechanisms and has a number of physiological consequences (for a review
see Ref. 31). Ca2+-stimulated CREB-dependent
gene transcription in the hippocampus requires ERKI/II activation and
supports learning and memory (37, 51, 52). Moreover, the same signal
transduction pathway that is important for synaptic plasticity also
contributes to neuronal survival. For example, brain-derived
neurotrophic factor blocks apoptosis in cortical neurons by stimulation
of the MAPK pathway (53, 54). Possible mechanisms linking odorant
receptor stimulation to ERK/MAP kinase activity include those
proceeding through Ras-GRF (44) and cAMP-GEFs (55). Indirect mechanisms
for stimulation of Ras activity via PKA and CaMKII have also been
demonstrated (56-59). KN-62 has been reported to have
nonkinase-directed effects including blockade of calcium and/or
potassium channels. To discount these possibilities from our
observations, we also treated cultured OSNs with the calcium ionophore
A23187 with and without KN-62 preincubation. A23187 stimulated a robust
ERK I/II phosphorylation that was significantly inhibited by KN-62,
indicating that KN-62 most likely exerts its inhibition of
odorant-stimulated ERK I/II phosphorylation downstream of membrane ion
channels, on CaMKII. Our finding that inhibition of CaMKII
activity attenuates the odorant and Ca2+ ionophore
stimulation of ERK I/II phosphorylation is, to our knowledge, the first
such observation in olfactory neurons. A novel implication is that
CaMKII, which phosphorylates and inhibits AC3, links the termination of
the cAMP signal to activation of ERK/MAP kinase. This raises the
interesting concept that CaMKII functions as a "gatekeeper" in
regulating downstream signaling in OSNs.
Transcription of gene families activated through the CREB/CRE pathway
is thought to a play a major role in several forms of neuroplasticity
in the CNS including long lasting long term potentiation and
memory for contextual and passive avoidance-associative learning (32,
33). Furthermore, a brief exposure to light during the subjective night
activates the ERK/MAP kinase signaling cascade in suprachiasmatic
nuclei, and there are striking circadian variations in MAPK activity
and CRE-mediated transcription within the suprachiasmatic nuclei,
suggesting that the MAPK cascade is involved in clock rhythmicity (60,
61). Activation of CRE-mediated transcription may also play an
important role for developmental neuronal plasticity in the CNS (62,
63). In this study, we have discovered a new odorant-stimulated signal
transduction pathway in OSNs that activates the CREB/CRE
transcriptional pathway and provides a mechanistic framework with which
to understand long term adaptive changes in OSNs. Our data are the
first to show an activity-dependent stimulation of ERK/MAP
kinase signaling and CRE-mediated transcription in sensory neurons.
This discovery may broaden the regulatory role of the ERK/CREB/CRE
transcriptional pathway to include adaptive changes in sensory tissue.
Published, JBC Papers in Press, October 20, 2000, DOI 10.1074/jbc.M006703200
The abbreviations used are:
CNG, cyclic
nucleotide-gated;
OSNs, olfactory sensory neurons;
CRE, cAMP-response
element;
CREB, cAMP-response element-binding protein;
AC3, type III
adenylyl cyclase;
CaM, calmodulin;
CaMKII, CaM-dependent
protein kinase II;
PKA, cAMP-dependent protein kinase;
PKC, protein kinase C;
CNS, central nervous system;
ERK, extracellular signal-regulated kinase;
MAP, mitogen-activated protein;
MAPK, MAP kinase;
MEK, ERK/MAPK kinase;
EOG, electro-olfactogram.
1.
|
Buck, L.,
and Axel, R.
(1991)
Cell
65,
175-187[Medline]
[Order article via Infotrieve]
|
2.
|
Levy, N. S.,
Bakalyar, H. A.,
and Reed, R. R.
(1991)
J. Steroid Biochem. Mol. Biol.
39,
633-637[CrossRef][Medline]
[Order article via Infotrieve]
|
3.
|
Parmentier, M.,
Libert, F.,
Schurmans, S.,
Schiffmann, S.,
Lefort, A.,
Eggerickx, D.,
Ledent, C.,
Mollereau, C.,
Gerard, C.,
Perret, J.,
Grootegoed, A.,
and Vassart, G.
(1992)
Nature
355,
453-455[CrossRef][Medline]
[Order article via Infotrieve]
|
4.
|
Mombaerts, P.,
Wang, F.,
Dulac, C.,
Chao, S. K.,
Nemes, A.,
Mendelsohn, M.,
Edmondson, J.,
and Axel, R.
(1996)
Cell
87,
675-686[Medline]
[Order article via Infotrieve]
|
5.
|
Malnic, B.,
Hirono, J.,
Sato, T.,
and Buck, L. B.
(1999)
Cell
96,
713-723[Medline]
[Order article via Infotrieve]
|
6.
|
Duchamp-Viret, P.,
Chaput, M. A.,
and Duchamp, A.
(1999)
Science
284,
2171-2774[Abstract/Free Full Text]
|
7.
|
Pace, U.,
Hanski, E.,
Salomon, Y.,
and Lancet, D.
(1985)
Nature
316,
255-258[Medline]
[Order article via Infotrieve]
|
8.
|
Sklar, P. B.,
Anholt, R. R.,
and Snyder, S. H.
(1986)
J. Biol. Chem.
261,
15538-15543[Abstract/Free Full Text]
|
9.
|
Lowe, G.,
Nakamura, T.,
and Gold, G. H.
(1989)
Proc. Natl. Acad. Sci. U. S. A.
86,
5641-5645
|
10.
|
Breer, H.,
Boekhoff, I.,
and Tareilus, E.
(1990)
Nature
345,
65-68[CrossRef][Medline]
[Order article via Infotrieve]
|
11.
|
Nakamura, T.,
and Gold, G. H.
(1987)
Nature
325,
442-444[CrossRef][Medline]
[Order article via Infotrieve]
|
12.
|
Belluscio, L.,
Gold, G. H.,
Nemes, A.,
and Axel, R
(1998)
Neuron
20,
69-81[Medline]
[Order article via Infotrieve]
|
13.
|
Wong, S. T.,
Trinh, K.,
Hacker, B.,
Chan, G. C.,
Lowe, G.,
Gaggar, A.,
Xia, Z.,
Gold, G. H.,
and Storm, D. R.
(2000)
Neuron
27,
487-497[Medline]
[Order article via Infotrieve]
|
14.
|
Brunet, L. J.,
Gold, G. H.,
and Ngai, J.
(1996)
Neuron
17,
681-693[Medline]
[Order article via Infotrieve]
|
15.
|
Zufall, F.,
Shepherd, G. M.,
and Firestein, S.
(1991)
Proc. R. Soc. Lond.
246,
225-230[Medline]
[Order article via Infotrieve]
|
16.
|
Frings, S.,
Benz, S.,
and Lindeman, B.
(1991)
J. Gen. Physiol.
97,
725-747[Abstract]
|
17.
|
Leinders Zufall, T.,
Rand, M. N.,
Shepherd, G. M.,
Greer, C. A.,
and Zufall, F.
(1997)
J. Neurosci.
17,
4136-4148[Abstract/Free Full Text]
|
18.
|
Borisy, F. F.,
Ronnett, G. V.,
Cunningham, A. M.,
Juilfs, D.,
Beavo, J.,
and Snyder, S. H.
(1992)
J. Neurosci.
12,
915-923[Abstract]
|
19.
|
Wayman, G. A.,
Impey, S.,
and Storm, D. R.
(1995)
J. Biol. Chem.
270,
21480-21486[Abstract/Free Full Text]
|
20.
|
Wei, J.,
Wayman, G.,
and Storm, D. R.
(1996)
J. Biol. Chem.
271,
24231-24235[Abstract/Free Full Text]
|
21.
|
Wei, J.,
Zhao, A. Z.,
Chan, G. C.,
Baker, L. P.,
Impey, S.,
Beavo, J. A.,
and Storm, D. R.
(1998)
Neuron
21,
495-504[Medline]
[Order article via Infotrieve]
|
22.
|
Leinders-Zufall, T.,
Ma, M.,
and Zufall, F.
(1999)
J. Neurosci.
19,
1-6[Abstract/Free Full Text]
|
23.
|
Dawson, T. M.,
Arriza, J. L.,
Jaworsky, D. E.,
Borisy, F. F.,
Attramadal, H.,
Lefkowitz, R. J.,
and Ronnett, G. V.
(1993)
Science
259,
825-829
|
24.
|
Peppel, K.,
Boekhoff, I.,
McDonald, P.,
Breer, H.,
Caron, M. G.,
and Lefkowitz, R. J.
(1997)
J. Biol. Chem.
272,
25425-25428[Abstract/Free Full Text]
|
25.
|
Boekhoff, I.,
and Breer, H.
(1992)
Proc. Natl. Acad. Sci. U. S. A.
89,
471-474[Abstract]
|
26.
|
Dittman, A. H.,
Quinn, T. P.,
Nevitt, G. A.,
Hacker, B.,
and Storm, D. R.
(1997)
Neuron
19,
381-389[CrossRef][Medline]
[Order article via Infotrieve]
|
27.
|
Wang, H. W.,
Wysocki, C. J.,
and Gold, G. H.
(1993)
Science
260,
998-1000
|
28.
|
Ronnett, G. V.,
Parfitt, D. J.,
Hester, L. D.,
and Snyder, S. H.
(1991)
Proc. Natl. Acad. Sci. U. S. A.
88,
2366-2369[Abstract]
|
29.
|
Tully, T.
(1998)
Nat. Neurosci.
1,
543-545[CrossRef][Medline]
[Order article via Infotrieve]
|
30.
|
Silva, A. J.,
Kogan, J. H.,
Frankland, P. W.,
and Kida, S
(1998)
Annu. Rev. Neurosci.
21,
127-148[CrossRef][Medline]
[Order article via Infotrieve]
|
31.
|
Impey, S.,
Obrietan, K.,
and Storm, D. R.
(1999)
Neuron
23,
11-14[Medline]
[Order article via Infotrieve]
|
32.
|
Impey, S.,
Mark, M.,
Villacres, E. C.,
Poser, S.,
Chavkin, C.,
and Storm, D. R.
(1996)
Neuron
16,
973-982[Medline]
[Order article via Infotrieve]
|
33.
|
Impey, S.,
Smith, D. M.,
Obrietan, K.,
Donahue, R.,
Wade, C.,
and Storm, D. R.
(1998)
Nat. Neurosci.
1,
595-601[CrossRef][Medline]
[Order article via Infotrieve]
|
34.
|
Rosen, L. B.,
Ginty, D. D.,
Weber, M. J.,
and Greenberg, M. E.
(1994)
Neuron
12,
1207-1221[Medline]
[Order article via Infotrieve]
|
35.
|
Vossler, M. R.,
Yao, H.,
York, R. D.,
Pan, M. G.,
Rim, C. S.,
and Stork, P. J.
(1997)
Cell
89,
73-82[Medline]
[Order article via Infotrieve]
|
36.
|
Martin, K. C.,
Michael, D.,
Rose, J. C.,
Barad, M.,
Casadio, A.,
Zhu, H.,
and Kandel, E. R.
(1997)
Neuron
18,
899-912[Medline]
[Order article via Infotrieve]
|
37.
|
Impey, S.,
Obrietan, K.,
Wong, S. T.,
Poser, S.,
Yano, S.,
Wayman, G.,
Deloulme, J. C.,
Chan, G.,
and Storm, D. R.
(1998)
Neuron
21,
869-883[Medline]
[Order article via Infotrieve]
|
38.
|
Zufall, F.,
Firestein, S.,
and Shepherd, G. M.
(1991)
J. Neurosci.
11,
3573-3580[Abstract]
|
39.
|
Lowe, G.,
and Gold, G. H.
(1991)
J. Physiol. (Lond.)
442,
147-168[Abstract]
|
40.
|
Favata, M. F.,
Horiuchi, K. Y.,
Manos, E. J.,
Daulerio, A. J.,
Stradley, D. A.,
Feeser, W. S.,
Van Dyk, D. E.,
Pitts, W. J.,
Earl, R. A.,
Hobbs, F.,
Copeland, R. A.,
Magolda, R. L.,
Scherle, P. A.,
and Trzaskos, J. M.
(1998)
J. Biol. Chem.
273,
18623-18632[Abstract/Free Full Text]
|
41.
|
Yamamoto, K. K.,
Gonzalez, G. A.,
Biggs, W. H.,
and Montminy, M. R.
(1988)
Nature
334,
494-498[CrossRef][Medline]
[Order article via Infotrieve]
|
42.
|
Gonzalez, G. A.,
and Montminy, M. R.
(1989)
Cell
59,
675-680[Medline]
[Order article via Infotrieve]
|
43.
|
Moon, C.,
Sung, Y. K.,
Reddy, R.,
and Ronnett, G. V.
(1999)
Proc. Natl. Acad. Sci. U. S. A.
96,
14605-14610[Abstract/Free Full Text]
|
44.
|
Chen, H. J.,
Rojas-Soto, M.,
Oguni, A.,
and Kennedy, M. B.
(1998)
Neuron
20,
895-904[Medline]
[Order article via Infotrieve]
|
45.
|
Kramer, R. H.,
and Siegelbaum, S. A.
(1992)
Neuron
9,
897-906[CrossRef][Medline]
[Order article via Infotrieve]
|
46.
|
Kurahashi, T.,
and Menini, A.
(1997)
Nature
385,
725-729[CrossRef][Medline]
[Order article via Infotrieve]
|
47.
|
Ginty, D. D.,
Bonni, A.,
and Greenberg, M. E.
(1994)
Cell
77,
713-725[Medline]
[Order article via Infotrieve]
|
48.
|
Sun, P.,
Enslen, H.,
Myung, P. S.,
and Maurer, R. A.
(1994)
Genes Dev.
8,
2527-2539
|
49.
|
Enslen, H.,
Sun, P.,
Brickey, D.,
Soderling, S. H.,
Klamo, E.,
and Soderling, T. R.
(1994)
J. Biol. Chem.
269,
15520-15527[Abstract/Free Full Text]
|
50.
|
Hirotsu, T.,
Saeki, S.,
Yamamoto, M.,
and Iino, Y.
(2000)
Nature
404,
289-293[CrossRef][Medline]
[Order article via Infotrieve]
|
51.
|
Atkins, C. M.,
Selcher, J. C.,
Petraitis, J. J.,
Trzaskos, J. M.,
and Sweatt, J. D.
(1998)
Nat. Neurosci.
1,
602-609[CrossRef][Medline]
[Order article via Infotrieve]
|
52.
|
Blum, S.,
Moore, A. N.,
Adams, F.,
and Dash, P. K.
(1999)
J. Neurosci.
19,
3535-3544[Abstract/Free Full Text]
|
53.
|
Xia, Z.,
Dickens, M.,
Raingeaud, J.,
Davis, R. J.,
and Greenberg, M. E.
(1995)
Science
270,
1326-1331[Abstract]
|
54.
|
Hetman, M.,
Kanning, K.,
Cavanaugh, J. E.,
and Xia, Z.
(1999)
J. Biol. Chem.
274,
22569-22580[Abstract/Free Full Text]
|
55.
|
Kawasaki, H.,
Springett, G. M.,
Mochizuki, N.,
Toki, S.,
Nakaya, M.,
Matsuda, M.,
Housman, D. E.,
and Graybiel, A. M.
(1998)
Science
282,
2275-2279[Abstract/Free Full Text]
|
56.
|
Farnsworth, C. L.,
Freshney, N. W.,
Rosen, L. B.,
Ghosh, A.,
Greenberg, M. E.,
and Feig, L. A.
(1995)
Nature
376,
524-527[CrossRef][Medline]
[Order article via Infotrieve]
|
57.
|
Muthalif, M. M.,
Benter, I. F.,
Uddin, M. R.,
and Malik, K. U.
(1996)
J. Biol. Chem.
271,
30149-30157[Abstract/Free Full Text]
|
58.
|
Abraham, S. T.,
Benscoter, H. A.,
Schworer, C. M.,
and Singer, H. A.
(1997)
Circ. Res.
81,
575-584[Abstract/Free Full Text]
|
59.
|
Grewal, S. S.,
Horgan, A. M.,
York, R. D.,
Withers, G. S.,
Banker, G. A.,
and Stork, P. J.
(2000)
J. Biol. Chem.
275,
3722-3728[Abstract/Free Full Text]
|
60.
|
Obrietan, K.,
Impey, S.,
and Storm, D. R.
(1998)
Nat. Neurosci.
1,
693-700[CrossRef][Medline]
[Order article via Infotrieve]
|
61.
|
Obrietan, K.,
Impey, S.,
Smith, D.,
Athos, J.,
and Storm, D. R.
(1999)
J. Biol. Chem.
274,
17748-17756[Abstract/Free Full Text]
|
62.
|
Pham, T. A.,
Impey, S.,
Storm, D. R.,
and Stryker, M. P.
(1999)
Neuron
22,
63-72[Medline]
[Order article via Infotrieve]
|
63.
|
Barth, A. L.,
McKenna, M.,
Glazewski, S.,
Hill, P.,
Impey, S.,
Storm, D.,
and Fox, K.
(2000)
J. Neurosci
20,
4206-4216[Abstract/Free Full Text]
|