AN ADP-RIBOSYLATION-FACTOR(ARF)-LIKE PROTEIN INVOLVED IN REGULATED SECRETION

A rat ADP-ribosylation factor(ARF)-like protein named ARL184 was ident ified by cDNA cloning. The corresponding recombinant protein had an ap parent molecular mass of 22000. The deduced amino acid sequence had 55 % identity with the human ARL1 and four functional GTP-binding sites. Immuno-fluorescent confocal microscopy studies showed that ARL184 was present in the cytosol as well as in the Golgi apparatus, raising the possibility that it has a role in a secretory pathway. The involvement of this ARF-like protein in secretion was confirmed by demonstrating that ARL184 potentiated acetylcholine release in stably transfected PC 12 cells. Collectively these results suggest that this ARL protein is a component of a regulated secretory pathway involved in Ca2+-dependen t release of acetylcholine.