Lin H C, Gilman A G
Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, Texas 75235, USA.
J Biol Chem. 1996 Nov 8;271(45):27979-82. doi: 10.1074/jbc.271.45.27979.
Dynamin I is a 100-kDa GTPase that plays an important role in the recycling of synaptic vesicles. Hydrolysis of GTP by dynamin is thought to be a critical step in fission of coated pits to form coated vesicles. We report that the heterotrimeric G protein betagamma subunit complex (Gbetagamma) and phosphatidylinositol 4, 5-bisphosphate (PtdIns(4,5)P2) are negative and positive regulators of dynamin GTPase activity, respectively. Furthermore, the apparent affinity of dynamin for Gbetagamma is substantially enhanced by PtdIns(4,5)P2. However, the GTPase activity of oligomeric dynamin is unaffected by Gbetagamma. The effects of heterotrimeric G proteins on endocytosis may thus be mediated directly and not involve more remote aspects of their signaling properties.
发动蛋白I是一种100 kDa的GTP酶，在突触小泡的循环利用中起重要作用。发动蛋白水解GTP被认为是包被小窝分裂形成包被小泡的关键步骤。我们报告称，异源三聚体G蛋白βγ亚基复合物（Gβγ）和磷脂酰肌醇4,5-二磷酸（PtdIns(4,5)P2）分别是发动蛋白GTP酶活性的负调节因子和正调节因子。此外，PtdIns(4,5)P2可显著增强发动蛋白对Gβγ的表观亲和力。然而，寡聚发动蛋白的GTP酶活性不受Gβγ影响。因此，异源三聚体G蛋白对胞吞作用的影响可能是直接介导的，并不涉及其信号特性的更遥远方面。
