title: Characterization of a glucose-repressible ADP-ribosylation factor 3 (ARF3) from Saccharomyces cerevisiae.
abstract: ADP-ribosylation factors (ARFs) are highly conserved approximately 20-kDa guanine nucleotide-binding proteins that enhance the ADP-ribosyltransferase activity of cholera toxin, and are believed to participate in vesicular transport in both exocytic and endocytic pathways. Based on size, phylogenetic analysis, amino acid sequence, and gene structure, mammalian ARFs fall into three classes (class I, ARFs 1, 2, 3; class II, ARFs 4, 5; class III, ARF6). Two ARF genes (yARF1, yARF2) are known in Saccharomyces cerevisiae and believed to participate in vesicular trafficking in the Golgi system; the double deletion mutant is not viable. A third yeast ARF (yARF3) cDNA has been cloned by polymerase chain reaction-based procedures. It contains an open reading frame of 549 bases encoding a protein of 183 amino acids, with a deduced amino acid sequence more identical (60%) to that of the class III mammalian ARF than to those of the other two classes (52-56%). The yARF3 protein, however, reacted poorly with antibodies against any of the three classes of mammalian ARFs. In the presence of GTP, recombinant yARF3 protein stimulated cholera toxin-catalyzed auto-ADP-ribosylation. yARF3 gene transcription, similar to that of yARF2, was repressed by glucose. As yARF3 was not essential for cell viability and was not required for endoplasmic reticulum to Golgi protein transport, it may provide an opportunity to define an ARF function in another kind of vesicular trafficking.
authors.affiliation: Laboratory of Cellular Metabolism, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892.
authors.forename: F J
authors.initials: FJ
authors.lastname: Lee
authors.forename: L A
authors.initials: LA
authors.lastname: Stevens
authors.forename: Y L
authors.initials: YL
authors.lastname: Kao
authors.forename: J
authors.initials: J
authors.lastname: Moss
authors.forename: M
authors.initials: M
authors.lastname: Vaughan
mesh_terms: D020727:ADP-Ribosylation Factors; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015139:Blotting, Southern; D002417:Cattle; D004271:DNA, Fungal; D019204:GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D015966:Gene Expression Regulation, Fungal; D005947:Glucose / Q000378:metabolism*; D006801:Humans; D008969:Molecular Sequence Data; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid
chemical_list: D004271:DNA, Fungal; D019204:GTP-Binding Proteins; D020727:ADP-Ribosylation Factors; D005947:Glucose