title: Tyrosine phosphorylation of phospholipase D1 by v-Src does not per se result in activation.
abstract: The relationship between tyrosine phosphorylation and activation of phospholipase D1 (PLD1) by v-Src was examined. Co-expression of v-Src and PLD1 in COS-7 cells resulted in increased activity and marked tyrosine phosphorylation of PLD1. PLD activity was increased in membranes or immunoprecipitates prepared from these cells. Dephosphorylation of the immunoprecipitated enzyme by tyrosine phosphatase or phosphorylation by c-Src produced no changes in its activity. Tyrosine phosphorylation induced by v-Src caused a shift of the enzyme from the Triton-soluble to the Triton-insoluble fraction. v-Src and PLD1 could be co-immunoprecipitated from cells co-expressing these and were co-localized in the perinuclear region as assessed by immunofluorescence. Mutation of the palmitoylation sites of PLD1 significantly reduced tyrosine phosphorylation by v-Src. It is concluded that tyrosine phosphorylation of PLD1 by v-Src does not per se alter its activity. It is proposed that activation of PLD1 by v-Src in vivo may involve association/colocalization of the two proteins.
authors.affiliation: Howard Hughes Medical Institute and the Department of Molecular Physiology and Biophysics, Room 831 Light Hall, Vanderbilt University School of Medicine, Nashville, TN 37232, United States.
authors.forename: Wan-Ting
authors.initials: WT
authors.lastname: Ho
authors.forename: Zhi
authors.initials: Z
authors.lastname: Xie
authors.forename: Zhizhuang Joe
authors.initials: ZJ
authors.lastname: Zhao
authors.forename: John H
authors.initials: JH
authors.lastname: Exton
mesh_terms: D000818:Animals; D019556:COS Cells; D002522:Chlorocebus aethiops; D004789:Enzyme Activation; D047468:Immunoprecipitation; D015688:Oncogene Protein pp60(v-src) / Q000378:metabolism*; D010169:Palmitic Acids / Q000378:metabolism; D010739:Phospholipase D / Q000032:analysis / Q000737:chemistry / Q000378:metabolism*; D010766:Phosphorylation; D014443:Tyrosine / Q000378:metabolism*
chemical_list: D010169:Palmitic Acids; D014443:Tyrosine; D015688:Oncogene Protein pp60(v-src); D010739:Phospholipase D; C106801:phospholipase D1