期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1999
卷号：96
期号：14
页码：7843-7846
DOI：10.1073/pnas.96.14.7843
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Phospholipase C (PLC)-{beta}1 and PLC-{beta}2 are regulated by the Gq family of heterotrimeric G proteins and contain C2 domains. These domains are Ca2+-binding modules that serve as membrane-attachment motifs in a number of signal transduction proteins. To determine the role that C2 domains play in PLC-{beta}1 and PLC-{beta}2 function, we measured the binding of the isolated C2 domains to membrane bilayers. We found, unexpectedly, that these modules do not bind to membranes but they associate strongly and specifically to activated [guanosine 5'-[{gamma}-thio]triphosphate (GTP[{gamma}S])-bound] Gq subunits. The C2 domain of PLC-{beta}1 effectively suppressed the activation of the intact isozyme by Gq(GTP[{gamma}S]), indicating that the C2-Gq interaction may be physiologically relevant. C2 affinity for Gq(GTP[{gamma}S]) was reduced when Gq was deactivated to the GDP-bound state. Binding to activated Gi1 subunits or to G{beta}{gamma} subunits was not detected. Also, Gq(GTP[{gamma}S]) failed to associate with the C2 domain of PLC-{delta
