title: ADP-ribosylation factor-1 stimulates formation of nascent secretory vesicles from the trans-Golgi network of endocrine cells.
abstract: ADP-ribosylation factor (ARF) is a small GTP-binding protein that has been implicated in intracellular vesicular transport. ARF regulates the budding of vesicles that mediate endoplasmic reticulum to Golgi and intra-Golgi transport. It also plays an important role in maintaining the function and morphology of the Golgi apparatus. Using a permeabilized cell system derived from GH3 cells, we provide evidence that ARF-1 regulates the formation of nascent secretory vesicles from the trans-Golgi network. Both myristoylated and non-myristoylated forms of recombinant human ARF-1 enhanced secretory vesicle budding about 2-fold. A mutant lacking the first 17 N-terminal residues, as well as one that preferentially binds GDP (T31N) did not stimulate vesicle formation. In contrast, a mutant defective in GTP hydrolysis (Q71L) promoted vesicle budding. Strikingly, a peptide corresponding to the N terminus of human ARF-1 (amino acids 2-17) also stimulated vesicle budding from the trans-Golgi network, in marked contrast to its inhibitory effect on vesicular transport from the endoplasmic reticulum to Golgi. These data demonstrate that in endocrine cells, ARF-1 and in particular its N terminus play an essential role in the formation of secretory vesicles.
authors.affiliation: Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, Bronx, New York 10461, USA.
authors.forename: Y G
authors.initials: YG
authors.lastname: Chen
authors.forename: D
authors.initials: D
authors.lastname: Shields
mesh_terms: D020727:ADP-Ribosylation Factors; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D003001:Cloning, Molecular; D003594:Cytoplasmic Granules / Q000187:drug effects / Q000502:physiology*; D003600:Cytosol / Q000378:metabolism; D017931:DNA Primers; D004926:Escherichia coli; D019204:GTP-Binding Proteins / Q000096:biosynthesis / Q000502:physiology*; D006056:Golgi Apparatus / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D007700:Kinetics; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D010446:Peptide Fragments / Q000138:chemical synthesis / Q000494:pharmacology; D010903:Pituitary Gland, Anterior / Q000502:physiology; D017354:Point Mutation; D051381:Rats; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000494:pharmacology
chemical_list: D017931:DNA Primers; D010446:Peptide Fragments; D011994:Recombinant Proteins; D019204:GTP-Binding Proteins; D020727:ADP-Ribosylation Factors