title: Neuronal nitric oxide synthase-dependent S-nitrosylation of gephyrin regulates gephyrin clustering at GABAergic synapses.
abstract: Gephyrin, the principal scaffolding protein at inhibitory synapses, is essential for postsynaptic clustering of glycine and GABA type A receptors (GABA(A)Rs). Gephyrin cluster formation, which determines the strength of GABAergic transmission, is modulated by interaction with signaling proteins and post-translational modifications. Here, we show that gephyrin was found to be associated with neuronal nitric oxide synthase (nNOS), the major source of the ubiquitous and important signaling molecule NO in brain. Furthermore, we identified that gephyrin is S-nitrosylated in vivo. Overexpression of nNOS decreased the size of postsynaptic gephyrin clusters in primary hippocampal neurons. Conversely, inhibition of nNOS resulted in a loss of S-nitrosylation of gephyrin and the formation of larger gephyrin clusters at synaptic sites, ultimately increasing the number of cell surface expressed synaptic GABA(A)Rs. In conclusion, S-nitrosylation of gephyrin is important for homeostatic assembly and plasticity of GABAergic synapses.
authors.affiliation: Department of Chemistry, Institute of Biochemistry.
authors.forename: Borislav
authors.initials: B
authors.lastname: Dejanovic
authors.affiliation: Department of Chemistry, Institute of Biochemistry, Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, and Center for Molecular Medicine, University of Cologne, 50674 Cologne, Germany gschwarz@uni-koeln.de.
authors.forename: Guenter
authors.initials: G
authors.lastname: Schwarz
mesh_terms: D000818:Animals; D002352:Carrier Proteins / Q000378:metabolism*; D002461:Cell Line, Transformed; D003545:Cysteine / Q000031:analogs & derivatives / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000235:genetics; D006624:Hippocampus / Q000166:cytology; D006801:Humans; D008565:Membrane Proteins / Q000378:metabolism*; D051379:Mice; D052248:Nitric Oxide Synthase Type I / Q000235:genetics / Q000378:metabolism*; D017729:Presynaptic Terminals / Q000378:metabolism; D011963:Receptors, GABA-A / Q000378:metabolism; D026403:S-Nitrosothiols / Q000378:metabolism; D013569:Synapses / Q000378:metabolism*; D014162:Transfection; D050495:Vesicular Inhibitory Amino Acid Transport Proteins / Q000378:metabolism; D005680:gamma-Aminobutyric Acid / Q000378:metabolism*
chemical_list: D002352:Carrier Proteins; D008565:Membrane Proteins; D011963:Receptors, GABA-A; D026403:S-Nitrosothiols; D050495:Vesicular Inhibitory Amino Acid Transport Proteins; C492244:Viaat protein, mouse; C485184:enhanced green fluorescent protein; C073441:gephyrin; D049452:Green Fluorescent Proteins; D005680:gamma-Aminobutyric Acid; C021315:S-nitrosocysteine; D052248:Nitric Oxide Synthase Type I; D003545:Cysteine
keywords: GABAA receptor; S-nitrosylation; clustering; gephyrin; nNOS; post-translational modification