ADP-RIBOSYLATION FACTORS IN RAT PAROTID ACINAR-CELLS

ADP-ribosylation factor (Arf) is a 20 kDa polypeptide that is a member of the Ras superfamily of small molecular mass GTP-binding proteins. In addition to an essential role of Arf1 in vesicle budding, recent ob servations suggest a role for Arf6 in calcium-dependent exocytosis in bovine adrenal chromaffin cells. In rat parotid acinar cells, exocytos is is cAMP-dependent and our findings suggest an interaction of Arf1 w ith the secretory granules. We describe here the structural and functi onal background to the Arf proteins focusing on their role in rat paro tid acinar cells.