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  3. Several posttranslational modifications act in concert to regulate gephyrin scaffolding and GABAergic transmission

Several posttranslational modifications act in concert to regulate gephyrin scaffolding and GABAergic transmission

  • Nat Commun. 2016 Nov 7;7:13365. doi: 10.1038/ncomms13365.
Himanish Ghosh 1 2,  Luca Auguadri 1,  Sereina Battaglia 1,  Zahra Simone Thirouin 1 2,  Khaled Zemoura 1 2,  Simon Messner 3,  Mario A Acuña 1 2,  Hendrik Wildner 1 2,  Gonzalo E Yévenes 1,  Andrea Dieter 1,  Hiroshi Kawasaki 4,  Michael O Hottiger 3,  Hanns Ulrich Zeilhofer 1 2 5,  Jean-Marc Fritschy 1 2,  Shiva K Tyagarajan 1 2
Affiliations

Affiliations

  • 1 Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, CH 8057 Zurich, Switzerland.
  • 2 Center for Neuroscience Zurich, CH 8057 Zurich, Switzerland.
  • 3 Department of Molecular Mechanisms of Disease, University of Zurich, CH 8057 Zurich, Switzerland.
  • 4 Department of Molecular and Systems Neurobiology, Graduate School of Medicine, The University of Tokyo, Tokyo 113-0033, Japan.
  • 5 Institute of Pharmaceutical Sciences, Swiss Federal Institute of Technology, CH 8093 Zurich, Switzerland.
PMID: 27819299 DOI: 10.1038/ncomms13365
Abstract

GABAA receptors (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.

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