Protein kinase C-dependent growth-associated protein 43 phosphorylation regulates gephyrin aggregation at Developing GABAergic synapses

TY - JOUR

T1 - Protein kinase C-dependent growth-associated protein 43 phosphorylation regulates gephyrin aggregation at Developing GABAergic synapses

AU - Wang, Chen Yu

AU - Lin, Hui Ching

AU - Song, Yi Ping

AU - Hsu, Yu Ting

AU - Lin, Shu Yu

AU - Hsu, Pei Chien

AU - Lin, Chun Hua

AU - Hung, Chia Chi

AU - Hsu, Min Ching

AU - Kuo, Yi Min

AU - Lee, Yih Jing

AU - Hsu, Chung Y.

AU - Leea, Yi Hsuan

N1 - Publisher Copyright: © 2015, American Society for Microbiology.

PY - 2015

Y1 - 2015

N2 - Growth-associated protein 43 (GAP43) is known to regulate axon growth, but whether it also plays a role in synaptogenesis remains unclear. Here, we found that GAP43 regulates the aggregation of gephyrin, a pivotal protein for clustering postsynaptic GABAA receptors (GABAARs), in developing cortical neurons. Pharmacological blockade of either protein kinase C (PKC) or neuronal activity increased both GAP43-gephyrin association and gephyrin misfolding-induced aggregation, suggesting the importance of PKC-dependent regulation of GABAergic synapses. Furthermore, we found that PKC phosphorylation-resistant GAP43S41A, but not PKC phosphorylation-mimicking GAP43S41D, interacted with cytosolic gephyrin to trigger gephyrin misfolding and its sequestration into aggresomes. In contrast, GAP43S41D, but not GAP43S41A, inhibited the physiological aggregation/clustering of gephyrin, reduced surface GABAARs under physiological conditions, and attenuated gephyrin misfolding under transient oxygen-glucose deprivation (tOGD) that mimics pathological neonatal hypoxia. Calcineurin-mediated GAP43 dephosphorylation that accompanied tOGD also led to GAP43-gephyrin association and gephyrin misfolding. Thus, PKC-dependent phosphorylation of GAP43 plays a critical role in regulating postsynaptic gephyrin aggregation in developing GABAergic synapses.

AB - Growth-associated protein 43 (GAP43) is known to regulate axon growth, but whether it also plays a role in synaptogenesis remains unclear. Here, we found that GAP43 regulates the aggregation of gephyrin, a pivotal protein for clustering postsynaptic GABAA receptors (GABAARs), in developing cortical neurons. Pharmacological blockade of either protein kinase C (PKC) or neuronal activity increased both GAP43-gephyrin association and gephyrin misfolding-induced aggregation, suggesting the importance of PKC-dependent regulation of GABAergic synapses. Furthermore, we found that PKC phosphorylation-resistant GAP43S41A, but not PKC phosphorylation-mimicking GAP43S41D, interacted with cytosolic gephyrin to trigger gephyrin misfolding and its sequestration into aggresomes. In contrast, GAP43S41D, but not GAP43S41A, inhibited the physiological aggregation/clustering of gephyrin, reduced surface GABAARs under physiological conditions, and attenuated gephyrin misfolding under transient oxygen-glucose deprivation (tOGD) that mimics pathological neonatal hypoxia. Calcineurin-mediated GAP43 dephosphorylation that accompanied tOGD also led to GAP43-gephyrin association and gephyrin misfolding. Thus, PKC-dependent phosphorylation of GAP43 plays a critical role in regulating postsynaptic gephyrin aggregation in developing GABAergic synapses.

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U2 - 10.1128/MCB.01332-14

DO - 10.1128/MCB.01332-14

M3 - Article

C2 - 25755278

AN - SCOPUS:84929206782

SN - 0270-7306

VL - 35

SP - 1712

EP - 1726

JO - Molecular and Cellular Biology

JF - Molecular and Cellular Biology

IS - 10

ER -