Gephyrin clustering is required for the stability of GABAergic synapses.
Although gephyrin is an important postsynaptic scaffolding protein at GABAergic synapses, the role of gephyrin for GABAergic synapse formation and/or maintenance is still under debate. We report here that knocking down gephyrin expression with small hairpin RNAs (shRNAs) in cultured hippocampal pyramidal cells decreased both the number of gephyrin and GABA(A) receptor clusters. Similar results were obtained by disrupting the clustering of endogenous gephyrin by overexpressing a gephyrin-EGFP fusion protein that formed aggregates with the endogenous gephyrin. Disrupting postsynaptic gephyrin clusters also had transsynaptic effects leading to a significant reduction of GABAergic presynaptic boutons contacting the transfected pyramidal cells. Consistent with the morphological decrease of GABAergic synapses, electrophysiological analysis revealed a significant reduction in both the amplitude and frequency of the spontaneous inhibitory postsynaptic currents (sIPSCs). However, no change in the whole-cell GABA currents was detected, suggesting a selective effect of gephyrin on GABA(A) receptor clustering at postsynaptic sites. It is concluded that gephyrin plays a critical role for the stability of GABAergic synapses.
Yu
Wendou
W
Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT 06269, USA.
Jiang
Min
M
Miralles
Celia P
CP
Li
Rong-Wen
RW
Chen
Gong
G
de Blas
Angel L
AL
D000818:Animals; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D002478:Cells, Cultured; D015536:Down-Regulation / Q000235:genetics; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D006624:Hippocampus / Q000378:metabolism* / Q000648:ultrastructure; D053444:Inhibitory Postsynaptic Potentials / Q000235:genetics; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D009433:Neural Inhibition / Q000235:genetics; D009434:Neural Pathways / Q000378:metabolism / Q000648:ultrastructure; D017729:Presynaptic Terminals / Q000378:metabolism / Q000648:ultrastructure; D017966:Pyramidal Cells / Q000378:metabolism* / Q000648:ultrastructure; D034741:RNA, Small Interfering; D051381:Rats; D017207:Rats, Sprague-Dawley; D011940:Receptor Aggregation / Q000235:genetics*; D011963:Receptors, GABA-A / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D013569:Synapses / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D009435:Synaptic Transmission / Q000235:genetics; D005680:gamma-Aminobutyric Acid / Q000378:metabolism*
D002352:Carrier Proteins; D008565:Membrane Proteins; D034741:RNA, Small Interfering; D011963:Receptors, GABA-A; D011993:Recombinant Fusion Proteins; C485184:enhanced green fluorescent protein; C073441:gephyrin; D049452:Green Fluorescent Proteins; D005680:gamma-Aminobutyric Acid