MYRISTOYLATION IS REQUIRED FOR THE INTRACELLULAR-LOCALIZATION AND ENDOCYTIC FUNCTION OF ARF6

ADP-ribosylation factors (ARFs) are modified by a myristate group that is covalently linked to the second glycine residue at the amino termi nus. With the recent evidence that ARF6 localizes to the cell peripher y and plays a regulatory role in endocytic traffic, we have investigat ed the role of myristoylation on the membrane association, biological activity, and subcellular distribution of ARF6 in intact cells. A Gly2 Ala mutation produced a nonmyristoylated protein that failed to associ ate with membranes, was cytosolic, and had no effect on endocytic tran sport. To determine if a different form of lipid modification could re store membrane association and biological activity, a nonmyristoylated ARF6 derivative was constructed that contained a prenyl group at the carboxy terminus. Prenylated ARF6 bound efficiently to membranes, but had no effect on receptor-mediated endocytosis and was mislocalized to distinct intracellular structures. Thus, although prenylation can rep lace myristoylation for membrane association, the latter appears to be critical for the proper targeting and biological activity of ARF6. (C ) 1995 Academic Press, Inc.