title: ADP-ribosylation of rho p21 inhibits lysophosphatidic acid-induced protein tyrosine phosphorylation and phosphatidylinositol 3-kinase activation in cultured Swiss 3T3 cells.
abstract: Botulinum C3 exoenzyme was used to specifically ADP-ribosylate and inactivate rho p21, and the effects of rho p21 inactivation on lysophosphatidic acid (LPA)-induced tyrosine phosphorylation were examined in cultured Swiss 3T3 cells. LPA induced a rapid increase in the tyrosine phosphorylation of a number of proteins. Pretreatment of the cells with the C3 exoenzyme caused ADP-ribosylation of rho p21 in the cells and selectively attenuated the phosphorylation of several proteins, including p43 mitogen-activated protein kinase, p125 focal adhesion kinase, and two proteins of 72 and 88 kDa. C3 exoenzyme pretreatment did not block the initial phosphorylation and activation of mitogen-activated protein kinase but suppressed its subsequent rise. In contrast, the enzyme treatment inhibited the induction of phosphorylation of the 72- and 88-kDa proteins and suppressed the basal and LPA-induced tyrosine phosphorylation of p125 focal adhesion kinase. In addition, immunoprecipitation of cell lysates with an antibody directed against the 85-kDa subunit of phosphatidylinositol 3-kinase (PI 3-kinase) co-precipitated a tyrosine-phosphorylated band of 180 kDa. C3 exoenzyme pretreatment suppressed both the phosphorylation of this band and PI 3-kinase activation associated with LPA stimulation. These findings suggest that rho p21 works as a link between the LPA receptor signal and the subsequent tyrosine phosphorylation and PI 3-kinase activation in these cells.
authors.affiliation: Department of Pharmacology, Kyoto University Faculty of Medicine, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Kumagai
authors.forename: N
authors.initials: N
authors.lastname: Morii
authors.forename: K
authors.initials: K
authors.lastname: Fujisawa
authors.forename: Y
authors.initials: Y
authors.lastname: Nemoto
authors.forename: S
authors.initials: S
authors.lastname: Narumiya
mesh_terms: D016475:3T3 Cells; D036002:ADP Ribose Transferases / Q000378:metabolism; D000246:Adenosine Diphosphate Ribose / Q000378:metabolism*; D000818:Animals; D001483:Base Sequence; D001905:Botulinum Toxins; D004789:Enzyme Activation; D019204:GTP-Binding Proteins / Q000378:metabolism*; D008246:Lysophospholipids / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D051379:Mice; D008969:Molecular Sequence Data; D009838:Oligodeoxyribonucleotides; D019869:Phosphatidylinositol 3-Kinases; D010766:Phosphorylation; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000378:metabolism*; D011494:Protein Kinases / Q000378:metabolism; D014443:Tyrosine / Q000378:metabolism*; D020742:rhoA GTP-Binding Protein
chemical_list: D008246:Lysophospholipids; D009838:Oligodeoxyribonucleotides; D000246:Adenosine Diphosphate Ribose; D014443:Tyrosine; D036002:ADP Ribose Transferases; C063007:exoenzyme C3, Clostridium botulinum; D011494:Protein Kinases; D019869:Phosphatidylinositol 3-Kinases; D017853:Phosphotransferases (Alcohol Group Acceptor); D001905:Botulinum Toxins; D019204:GTP-Binding Proteins; D020742:rhoA GTP-Binding Protein