8.A.125.  The Cleft Lip and Palate Transmembrane Protein 1 (Clptm1) Family

GABAAR-associated proteins include the Cleft lip and palate transmembrane protein 1 (Clptm1) which interacts with all GABAAR subunits and promotes GABAAR trapping in the endoplasmic reticulum (Ge et al. 2018). Overexpression of Clptm1 reduces GABAAR-mediated currents in cultured hippocampal neurons and in brain with no effect on glycine or AMPA receptor-mediated currents. Conversely, knockdown of Clptm1 increased phasic and tonic inhibitory transmission with no effect on excitatory synaptic transmission. Furthermore, altering the expression level of Clptm1 mimicked activity-induced inhibitory synaptic scaling. Thus, in complement to other GABAAR-associated proteins that promote receptor surface expression, Clptm1 limits GABAAR forward trafficking and regulates inhibitory homeostatic plasticity (Ge et al. 2018).