title: XL alpha s is a new type of G protein.
abstract: The GTP-binding proteins are well-known regulators of cellular functions, including vesicular transport. Cholera toxin, which is known to catalyse ADP-ribosylation of the alpha s subunit of heterotrimeric G proteins, stimulates secretory vesicle formation from the trans-Golgi network. Here we describe a new cholera toxin target, an 'extra large' G protein (XL alpha s; M(r) 92K) which consists of a new 51K XL-portion linked to a G alpha s truncated at the amino terminus. XL alpha s is specifically associated with the trans-Golgi network and occurs selectively in cells containing both the regulated and the constitutive pathway of protein secretion. Hence, XL alpha s may mediate the effects of cholera toxin on secretory vesicle formation.
authors.affiliation: Institute for Neurobiology, University of Heidelberg, Germany.
authors.forename: R H
authors.initials: RH
authors.lastname: Kehlenbach
authors.forename: J
authors.initials: J
authors.lastname: Matthey
authors.forename: W B
authors.initials: WB
authors.lastname: Huttner
mesh_terms: D000246:Adenosine Diphosphate Ribose / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002772:Cholera Toxin / Q000494:pharmacology; D002864:Chromogranins; D018076:DNA, Complementary; D019205:GTP-Binding Protein alpha Subunits, Gs; D019204:GTP-Binding Proteins / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D006056:Golgi Apparatus / Q000378:metabolism; D020962:Heterotrimeric GTP-Binding Proteins; D008565:Membrane Proteins / Q000378:metabolism; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins; D016716:PC12 Cells; D051381:Rats; D013347:Subcellular Fractions; D014018:Tissue Distribution
chemical_list: D002864:Chromogranins; D018076:DNA, Complementary; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D000246:Adenosine Diphosphate Ribose; D002772:Cholera Toxin; D019204:GTP-Binding Proteins; C498643:Gnas protein, rat; D019205:GTP-Binding Protein alpha Subunits, Gs; D020962:Heterotrimeric GTP-Binding Proteins