Regulation of dynamin I GTPase activity by G protein betagamma subunits and phosphatidylinositol 4,5-bisphosphate.
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.
Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, Texas 75235, USA.
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Gilman
D000818:Animals; D001923:Brain Chemistry; D002417:Cattle; D002846:Chromatography, Affinity; D034284:Dynamin I; D034281:Dynamins; D004789:Enzyme Activation; D020558:GTP Phosphohydrolases / Q000378:metabolism*; D019204:GTP-Binding Proteins / Q000378:metabolism*; D006801:Humans; D008870:Microtubules / Q000378:metabolism*; D019269:Phosphatidylinositol 4,5-Diphosphate / Q000378:metabolism*; D011487:Protein Conformation
D019269:Phosphatidylinositol 4,5-Diphosphate; D034284:Dynamin I; D020558:GTP Phosphohydrolases; D019204:GTP-Binding Proteins; D034281:Dynamins