Phospholipase C-related inactive protein is implicated in the constitutive internalization of GABAA receptors mediated by clathrin and AP2 adaptor complex.
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Kanematsu T, Fujii M, Mizokami A, Kittler JT, Nabekura J, Moss SJ, Hirata M
Phospholipase C-related inactive protein is implicated in the constitutive internalization of GABAA receptors mediated by clathrin and AP2 adaptor complex.
J Neurochem. 2007 May;101(4):898-905. Epub 2007 Jan 24.
- PubMed ID
- 17254016 [ View in PubMed]
- Abstract
A mechanism for regulating the strength of synaptic inhibition is enabled by altering the number of GABA(A) receptors available at the cell surface. Clathrin and adaptor protein 2 (AP2) complex-mediated endocytosis is known to play a fundamental role in regulating cell surface GABA(A) receptor numbers. Very recently, we have elucidated that phospholipase C-related catalytically inactive protein (PRIP) molecules are involved in the phosphorylation-dependent regulation of the internalization of GABA(A) receptors through association with receptor beta subunits and protein phosphatases. In this study, we examined the implications of PRIP molecules in clathrin-mediated constitutive GABA(A) receptor endocytosis, independent of phospho-regulation. We performed a constitutive receptor internalization assay using human embryonic kidney 293 (HEK293) cells transiently expressed with GABA(A) receptor alpha/beta/gamma subunits and PRIP. PRIP was internalized together with GABA(A) receptors, and the process was inhibited by PRIP-binding peptide which blocks PRIP binding to beta subunits. The clathrin heavy chain, mu2 and beta2 subunits of AP2 and PRIP-1, were complexed with GABA(A) receptor in brain extract as analyzed by co-immunoprecipitation assay using anti-PRIP-1 and anti-beta2/3 GABA(A) receptor antibody or by pull-down assay using beta subunits of GABA(A) receptor. These results indicate that PRIP is primarily implicated in the constitutive internalization of GABA(A) receptor that requires clathrin and AP2 protein complex.