title: Brefeldin A inhibits Golgi membrane-catalysed exchange of guanine nucleotide onto ARF protein.
abstract: The fungal metabolite brefeldin A is a powerful tool for investigating membrane traffic in eukaryotic cells. The effects of brefeldin A on traffic are partly explained by its ability to prevent binding of cytosolic coat proteins onto membranes. The non-clathrin coatomer complex binds reversibly to Golgi membranes in a GTP-controlled cycle. The low-molecular-mass GTP-binding protein ADP-ribosylation factor (ARF), which also associates reversibly with Golgi membranes, is required for coatomer binding and probably accounts for the control by guanine nucleotide of the coatomer-membrane interaction. Brefeldin A prevents the assembly of coatomer onto the membrane by inhibiting the GTP-dependent interaction of ARF with the Golgi membrane, but the nature of this interaction has not been established. Here we demonstrate that Golgi membranes can specifically catalyse the exchange of GTP onto ARF and that brefeldin A prevents this function.
authors.affiliation: Cell Biology and Metabolism Branch, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892.
authors.forename: J G
authors.initials: JG
authors.lastname: Donaldson
authors.forename: D
authors.initials: D
authors.lastname: Finazzi
authors.forename: R D
authors.initials: RD
authors.lastname: Klausner
mesh_terms: D020727:ADP-Ribosylation Factors; D000818:Animals; D020126:Brefeldin A; D016466:CHO Cells; D006224:Cricetinae; D003517:Cyclopentanes / Q000494:pharmacology*; D019204:GTP-Binding Proteins / Q000378:metabolism*; D006056:Golgi Apparatus / Q000648:ultrastructure*; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000378:metabolism; D006160:Guanosine Triphosphate / Q000378:metabolism*; D006801:Humans; D007425:Intracellular Membranes / Q000187:drug effects / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D014357:Trypsin / Q000494:pharmacology
chemical_list: D003517:Cyclopentanes; D011994:Recombinant Proteins; D020126:Brefeldin A; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D006160:Guanosine Triphosphate; D014357:Trypsin; D019204:GTP-Binding Proteins; D020727:ADP-Ribosylation Factors