| First Author | Wagner S | Year | 2021 |
| Journal | J Biol Chem | Volume | 296 |
| Pages | 100709 | PubMed ID | 33901490 |
| Mgi Jnum | J:309612 | Mgi Id | MGI:6707391 |
| Doi | 10.1016/j.jbc.2021.100709 | Citation | Wagner S, et al. (2021) The alpha3 subunit of GABAA receptors promotes formation of inhibitory synapses in the absence of collybistin. J Biol Chem :100709 |
| abstractText | Signaling at nerve cell synapses is a key determinant of proper brain function, and synaptic defects - or synaptopathies - are at the basis of many neurological and psychiatric disorders. Collybistin (CB), a brain-specific guanine nucleotide exchange factor (GEF), is essential for the formation of gamma-aminobutyric acidergic (GABAergic) postsynapses in defined regions of the mammalian forebrain, including the hippocampus and the basolateral amygdala. This process depends on a direct interaction of CB with the scaffolding protein gephyrin, which leads to the redistribution of gephyrin into submembranous clusters at nascent inhibitory synapses. Strikingly, synaptic clustering of gephyrin and GABAA receptors (GABAARs) in several brain regions, including the cerebral cortex and certain thalamic areas, is unperturbed in CB-deficient mice, indicating that the formation of a substantial subset of inhibitory postsynapses must be controlled by gephyrin-interacting proteins other than CB. Previous studies indicated that the alpha3 subunit of GABAARs (GABAAR-alpha3) binds directly and with high affinity to gephyrin. Here, we provide evidence (i) that a homooligomeric GABAAR-alpha3(A343W) mutant induces the formation of submembranous gephyrin clusters independently of CB in COS-7 cells, (ii) that gephyrin clustering is unaltered in the neuronal subpopulations endogenously expressing the GABAAR-alpha3 in CB-deficient brains, and (iii) that exogenous expression of GABAAR-alpha3 partially rescues impaired gephyrin clustering in CB-deficient hippocampal neurons. Our results identify an important role of GABAAR-alpha3 in promoting gephyrin-mediated and CB-independent formation of inhibitory postsynapses. |
