TY - JOUR
T1 - Homer1a-Dependent Crosstalk Between NMDA and Metabotropic Glutamate Receptors in Mouse Neurons
AU - Bertaso, Federica
AU - Roussignol, Gautier
AU - Worley, Paul
AU - Bockaert, Joël
AU - Fagni, Laurent
AU - Ango, Fabrice
PY - 2010
Y1 - 2010
N2 - Background: A large number of evidences suggest that group-I metabotropic glutamate receptors (mGluR1a, 1b, 1c, 5a, 5b) can modulate NMDA receptor activity. Interestingly, a physical link exists between these receptors through a Homer-Shank multi-protein scaffold that can be disrupted by the immediate early gene, Homer1a. Whether such a versatile link supports functional crosstalk between the receptors is unknown. Methodology/Principal Findings: Here we used biochemical, electrophysiological and molecular biological approaches in cultured mouse cerebellar neurons to investigate this issue. We found that Homer1a or dominant negative Shank3 mutants that disrupt the physical link between the receptors allow inhibition of NMDA current by group-I mGluR agonist. This effect is antagonized by pertussis toxin, but not thapsigargin, suggesting the involvement of a G protein, but not intracellular calcium stores. Also, this effect is voltage-sensitive, being present at negative, but not positive membrane potentials. In the presence of DHPG, an apparent NMDA "tail current" was evoked by large pulse depolarization, only in neurons transfected with Homer1a. Co-immunoprecipitation experiments showed interaction between G-protein βγ subunits and NMDA receptor in the presence of Homer1a and group-I mGluR agonist. Conclusions/Significance: Altogether these results suggest a direct inhibition of NMDA receptor-channel by Gbetagamma subunits, following disruption of the Homer-Shank3 complex by the immediate early gene Homer1a. This study provides a new molecular mechanism by which group-I mGluRs could dynamically regulate NMDA receptor function.
AB - Background: A large number of evidences suggest that group-I metabotropic glutamate receptors (mGluR1a, 1b, 1c, 5a, 5b) can modulate NMDA receptor activity. Interestingly, a physical link exists between these receptors through a Homer-Shank multi-protein scaffold that can be disrupted by the immediate early gene, Homer1a. Whether such a versatile link supports functional crosstalk between the receptors is unknown. Methodology/Principal Findings: Here we used biochemical, electrophysiological and molecular biological approaches in cultured mouse cerebellar neurons to investigate this issue. We found that Homer1a or dominant negative Shank3 mutants that disrupt the physical link between the receptors allow inhibition of NMDA current by group-I mGluR agonist. This effect is antagonized by pertussis toxin, but not thapsigargin, suggesting the involvement of a G protein, but not intracellular calcium stores. Also, this effect is voltage-sensitive, being present at negative, but not positive membrane potentials. In the presence of DHPG, an apparent NMDA "tail current" was evoked by large pulse depolarization, only in neurons transfected with Homer1a. Co-immunoprecipitation experiments showed interaction between G-protein βγ subunits and NMDA receptor in the presence of Homer1a and group-I mGluR agonist. Conclusions/Significance: Altogether these results suggest a direct inhibition of NMDA receptor-channel by Gbetagamma subunits, following disruption of the Homer-Shank3 complex by the immediate early gene Homer1a. This study provides a new molecular mechanism by which group-I mGluRs could dynamically regulate NMDA receptor function.
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U2 - 10.1371/journal.pone.0009755
DO - 10.1371/journal.pone.0009755
M3 - Article
C2 - 20305784
AN - SCOPUS:77955601200
SN - 1932-6203
VL - 5
JO - PloS one
JF - PloS one
IS - 3
M1 - e9755
ER -