Several posttranslational modifications act in concert to regulate gephyrin scaffolding and GABAergic transmission.
GABAAreceptors (GABAARs) mediate the majority of fast inhibitory neurotransmission in the brain via synergistic association with the postsynaptic scaffolding protein gephyrin and its interaction partners. However, unlike their counterparts at glutamatergic synapses, gephyrin and its binding partners lack canonical protein interaction motifs; hence, the molecular basis for gephyrin scaffolding has remained unclear. In this study, we identify and characterize two new posttranslational modifications of gephyrin, SUMOylation and acetylation. We demonstrate that crosstalk between SUMOylation, acetylation and phosphorylation pathways regulates gephyrin scaffolding. Pharmacological intervention of SUMO pathway or transgenic expression of SUMOylation-deficient gephyrin variants rescued gephyrin clustering in CA1 or neocortical neurons of Gabra2-null mice, which otherwise lack gephyrin clusters, indicating that gephyrin SUMO modification is an essential determinant for scaffolding at GABAergic synapses. Together, our results demonstrate that concerted modifications on a protein scaffold by evolutionarily conserved yet functionally diverse signalling pathways facilitate GABAergic transmission.
Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, CH 8057 Zurich, Switzerland.|Center for Neuroscience Zurich, CH 8057 Zurich, Switzerland.
Himanish
H
Ghosh
Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, CH 8057 Zurich, Switzerland.
Luca
L
Auguadri
Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, CH 8057 Zurich, Switzerland.
Sereina
S
Battaglia
Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, CH 8057 Zurich, Switzerland.|Center for Neuroscience Zurich, CH 8057 Zurich, Switzerland.
Zahra
Z
Simone Thirouin
Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, CH 8057 Zurich, Switzerland.|Center for Neuroscience Zurich, CH 8057 Zurich, Switzerland.
Khaled
K
Zemoura
Department of Molecular Mechanisms of Disease, University of Zurich, CH 8057 Zurich, Switzerland.
Simon
S
Messner
Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, CH 8057 Zurich, Switzerland.|Center for Neuroscience Zurich, CH 8057 Zurich, Switzerland.
Mario A
MA
Acuña
Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, CH 8057 Zurich, Switzerland.|Center for Neuroscience Zurich, CH 8057 Zurich, Switzerland.
Hendrik
H
Wildner
Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, CH 8057 Zurich, Switzerland.
Gonzalo E
GE
Yévenes
Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, CH 8057 Zurich, Switzerland.
Andrea
A
Dieter
Department of Molecular and Systems Neurobiology, Graduate School of Medicine, The University of Tokyo, Tokyo 113-0033, Japan.
Hiroshi
H
Kawasaki
Department of Molecular Mechanisms of Disease, University of Zurich, CH 8057 Zurich, Switzerland.
Michael
M
O Hottiger
Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, CH 8057 Zurich, Switzerland.|Center for Neuroscience Zurich, CH 8057 Zurich, Switzerland.|Institute of Pharmaceutical Sciences, Swiss Federal Institute of Technology, CH 8093 Zurich, Switzerland.
Hanns Ulrich
HU
Zeilhofer
Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, CH 8057 Zurich, Switzerland.|Center for Neuroscience Zurich, CH 8057 Zurich, Switzerland.
Jean-Marc
0000-0002-8552-3702
JM
Fritschy
Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, CH 8057 Zurich, Switzerland.|Center for Neuroscience Zurich, CH 8057 Zurich, Switzerland.
Shiva K
0000-0003-0074-1805
SK
Tyagarajan
D000107:Acetylation; D000818:Animals; D056547:CA1 Region, Hippocampal / Q000166:cytology / Q000502:physiology; D002352:Carrier Proteins / Q000378:metabolism / Q000502:physiology*; D005260:Female; D047309:Flavones / Q000494:pharmacology; D059330:GABAergic Neurons / Q000502:physiology*; D057809:HEK293 Cells; D006801:Humans; D008297:Male; D008565:Membrane Proteins / Q000378:metabolism / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D023421:Models, Animal; D019579:Neocortex / Q000166:cytology / Q000378:metabolism; D010766:Phosphorylation; D061251:Primary Cell Culture; D051381:Rats; D011963:Receptors, GABA-A / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*; D058207:Sumoylation / Q000187:drug effects; D013569:Synapses / Q000502:physiology; D009435:Synaptic Transmission / Q000502:physiology*
C000592084:2',3',4'-trihydroxyflavone; D002352:Carrier Proteins; D047309:Flavones; C493920:Gabra2 protein, mouse; D008565:Membrane Proteins; D011963:Receptors, GABA-A; C073441:gephyrin