PHOSPHOLIPASE C-BETA-1 IS A GTPASE-ACTIVATING PROTEIN FOR GQ/11, ITS PHYSIOLOGICAL REGULATOR
PHOSPHOLIPASE C-BETA-1 IS A GTPASE-ACTIVATING PROTEIN FOR GQ/11, ITS PHYSIOLOGICAL REGULATOR
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DOI：
10.1016/0092-8674(92)90165-9
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发表时间：
1992-08-07
期刊：
影响因子：
64.5
通讯作者：
ROSS, EM
中科院分区：
文献类型：
--
作者：
BERSTEIN, G;BLANK, JL;ROSS, EM
将纯化的M_1胆碱能受体和G（q/11）共重组于脂质囊泡中。加入纯化的磷脂酶C-β-1（PLC-β-1）进一步刺激受体促进的G（q/11）的稳态GT3活性高达20倍。刺激依赖于受体介导的GTP-GDP交换。加入PLC-β-1导致G（q/11）结合GTP的水解快速爆发，其比不存在时快至少50倍。因此，PLC-β-1刺激G（q/11）结合GTP的水解，并作为其生理调节剂G（q/11）的GTP酶激活蛋白（GAP）。GTP酶刺激活性对PLC-β-1和G均具有特异性（g/11）。通过与三聚体G蛋白偶联的效应物的这种GAP活性可以使体外纯G蛋白的缓慢GTP水解与G蛋白介导的信号传导的快速生理失活相协调。
Purified M1 muscarinic cholinergic receptor and G(q/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 G(q/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 G(q/11)-bound GTP that was at least 50-fold faster than in its absence. Thus, PLC-beta-1 stimulates hydrolysis of G(q/11)-bound GTP and acts as a GTPase-activating protein (GAP) for its physiologic regulator, G(q/11). GTPase-stimulating activity was specific both for PLC-beta-1 and G(g/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.