Sequestration of the G protein βγ subunit complex inhibits receptor-mediated endocytosis

Cell surface receptors that mediate endocytosis cluster into clathrin-coated pits, which pinch off to form vesicles that transport the receptors and their ligands. This multi-step process requires the coordinated action of many factors, including GTP-hydrolyzing proteins such as dynamin and regulators of actin cytoskeleton assembly. We note herein that sequestration of heterotrimeric G protein βγ subunits in intact cells strongly inhibits clathrin-coated pit-mediated endocytosis and causes rearrangement of the actin cytoskeleton. Our results suggest that cells contain a pool of free βγ and that it functions constitutively to permit endocytosis.