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Direct binding of GABA A receptor β2 and β3 subunits to gephyrin
Author(s) -
Kowalczyk Sarah,
Winkelmann Aline,
Smolinsky Birthe,
Förstera Benjamin,
Neundorf Ines,
Schwarz Guenter,
Meier Jochen C.
Publication year - 2013
Publication title -
european journal of neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.346
H-Index - 206
eISSN - 1460-9568
pISSN - 0953-816X
DOI - 10.1111/ejn.12078
Subject(s) - gephyrin , glycine receptor , postsynaptic potential , inhibitory postsynaptic potential , protein subunit , neurotransmission , receptor , microbiology and biotechnology , chemistry , biophysics , biology , glycine , biochemistry , neuroscience , amino acid , gene
GABA ergic transmission is essential to brain function, and a large repertoire of GABA type A receptor ( GABA A R ) subunits is at a neuron's disposition to serve this function. The glycine receptor (GlyR)‐associated protein gephyrin has been shown to be essential for the clustering of a subset of GABA A R . Despite recent progress in the field of gephyrin‐dependent mechanisms of postsynaptic GABA A R stabilisation, the role of gephyrin in synaptic GABA A R localisation has remained a complex matter with many open questions. Here, we analysed comparatively the interaction of purified rat gephyrin and mouse brain gephyrin with the large cytoplasmic loops of GABA A R α1, α2, β2 and β3 subunits. Binding affinities were determined using surface plasmon resonance spectroscopy, and showed an ~ 20‐fold lower affinity of the β2 loop to gephyrin as compared to the GlyR β loop–gephyrin interaction. We also probed in vivo binding in primary cortical neurons by the well‐established use of chimaeras of GlyR α1 that harbour respective gephyrin‐binding motifs derived from the different GABA A R subunits. These studies identify a novel gephyrin‐binding motif in GABA A R β2 and β3 large cytoplasmic loops.