磷脂酶C-β1是Gq/11（其生理调节因子）的一种GTP酶激活蛋白。

Phospholipase C-beta 1 is a GTPase-activating protein for Gq/11, its physiologic regulator.

作者信息

Berstein G, Blank J L, Jhon D Y, Exton J H, Rhee S G, Ross E M

机构信息

Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas 75235-9041.

出版信息

Cell. 1992 Aug 7;70(3):411-8. doi: 10.1016/0092-8674(92)90165-9.

DOI:10.1016/0092-8674(92)90165-9

PMID:1322796

Abstract

Purified M1 muscarinic cholinergic receptor and Gq/11 were coreconstituted in lipid vesicles. Addition of purified phospholipase C-beta 1 (PLC-beta 1) further stimulated the receptor-promoted steady-state GTPase activity of Gq/11 up to 20-fold. Stimulation depended upon receptor-mediated GTP-GDP exchange. Addition of PLC-beta 1 caused a rapid burst of hydrolysis of Gq/11-bound GTP that was at least 50-fold faster than in its absence. Thus, PLC-beta 1 stimulates hydrolysis of Gq/11-bound GTP and acts as a GTPase-activating protein (GAP) for its physiologic regulator, Gq/11. GTPase-stimulating activity was specific both for PLC-beta 1 and Gq/11. Such GAP activity by an effector coupled to a trimeric G protein can reconcile slow GTP hydrolysis by pure G proteins in vitro with fast physiologic deactivation of G protein-mediated signaling.

摘要

纯化的M1毒蕈碱胆碱能受体和Gq/11在脂质小泡中进行了共重组。添加纯化的磷脂酶C-β1（PLC-β1）可进一步将受体促进的Gq/11的稳态GTP酶活性刺激高达20倍。刺激作用取决于受体介导的GTP-GDP交换。添加PLC-β1会导致Gq/11结合的GTP迅速爆发水解，其速度比不添加时至少快50倍。因此，PLC-β1刺激Gq/11结合的GTP水解，并作为其生理调节因子Gq/11的GTP酶激活蛋白（GAP）。GTP酶刺激活性对PLC-β1和Gq/11均具有特异性。效应器与三聚体G蛋白偶联产生的这种GAP活性，可以使体外纯G蛋白缓慢的GTP水解与G蛋白介导的信号传导的快速生理失活相协调。