A REGULATORY ROLE FOR ARF6 IN RECEPTOR-MEDIATED ENDOCYTOSIS

Adenosine diphosphate-ribosylation factor 6 (ARF6), ARF6 mutants, and ARF1 were transiently expressed in Chinese hamster ovary cells, and th e effects on receptor-mediated endocytosis were assessed. Overexpresse d ARF6 localized to the cell periphery and led to a redistribution of transferrin receptors to the cell surface and a decrease in the rate o f uptake of transferrin. Similar results were obtained when a mutant d efective in guanosine triphosphate hydrolysis was expressed. Expressio n of a dominant negative mutant, ARF6(T27N), resulted in an intracellu lar distribution of transferrin receptors and an inhibition of transfe rrin recycling to the cell surface. In contrast, overexpression of ARF 1 had little or no effect on these parameters of endocytosis.