title: The membrane-tethering protein p115 interacts with GBF1, an ARF guanine-nucleotide-exchange factor.
abstract: The membrane-transport factor p115 interacts with diverse components of the membrane-transport machinery. It binds two Golgi matrix proteins, a Rab GTPase, and various members of the soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) family. Here, we describe a novel interaction between p115 and Golgi-specific brefeldin-A-resistant factor 1 (GBF1), a guanine-nucleotide exchange factor for ADP ribosylation factor (ARF). GBF1 was identified in a yeast two-hybrid screen, using full-length p115 as bait. The interaction was confirmed biochemically, using in vitro and in vivo assays. The interacting domains were mapped to the proline-rich region of GBF1 and the head region of p115. These proteins colocalize extensively in the Golgi and in peripheral vesicular tubular clusters. Mutagenesis analysis indicates that the interaction is not required for targeting GBF1 or p115 to membranes. Expression of the p115-binding (pro-rich) region of GBF1 leads to Golgi disruption, indicating that the interaction between p115 and GBF1 is functionally relevant.
authors.affiliation: Department of Cell Biology, University of Alabama at Birmingham, 1918 University Boulevard, MCLM 668, Birmingham, Alabama 35294, USA.
authors.forename: Rafael
authors.initials: R
authors.lastname: García-Mata
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Sztul
mesh_terms: D000818:Animals; D019556:COS Cells; D002522:Chlorocebus aethiops; D003001:Cloning, Molecular; D003600:Cytosol / Q000378:metabolism; D018076:DNA, Complementary / Q000235:genetics; D005455:Fluorescent Antibody Technique; D006056:Golgi Apparatus / Q000378:metabolism; D020662:Guanine Nucleotide Exchange Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D008099:Liver / Q000378:metabolism; D051381:Rats; D011994:Recombinant Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D064067:Rho Guanine Nucleotide Exchange Factors; D014162:Transfection
chemical_list: D018076:DNA, Complementary; C120445:GBF1 protein, human; D020662:Guanine Nucleotide Exchange Factors; D011994:Recombinant Proteins; D064067:Rho Guanine Nucleotide Exchange Factors