title: SHIP2 interaction with the cytoskeletal protein Vinexin.
abstract: The src homology 2 (SH2) domain-containing inositol 5-phosphatase 2 (SHIP2) catalyses the dephosphorylation of phosphatidylinositol 3,4,5-trisphosphate [PtdIns(3,4,5)P3] to phosphatidylinositol 3,4-bisphosphate [PtdIns(3,4)P2]. We report the identification of the cytoskeletal protein Vinexin as a protein interacting with SHIP2. This was achieved by yeast two-hybrid screening using the C-terminal region of SHIP2 as bait. Vinexin has previously been identified as a vinculin-binding protein that plays a key role in cell spreading and cytoskeletal organization. The interaction between SHIP2 and Vinexin was confirmed in lysates of both COS-7 cells and mouse embryonic fibroblasts (MEF). The C-terminus was involved in the interaction, as shown by the transfection of a truncated C-terminus mutant of SHIP2. In addition, we showed the colocalization between Vinexin alpha and SHIP2 at the periphery of transfected COS-7 cells. When added in vitro to SHIP2, Vinexin did not affect the PtdIns(3,4,5)P3 5-phosphatase activity of SHIP2. Enhanced cell adhesion to collagen-I-coated dishes was shown upon transfection of either SHIP2 or Vinexin to COS-7 cells. This effect was no longer observed with either a catalytic mutant or the C-terminus mutant of SHIP2. It also appears SHIP2 specific; this was not seen with SHIP1. Adhesion to the same matrix was decreased in SHIP2-/- MEF cells compared with MEF+/+ cells. Our data suggest that SHIP2 interaction with Vinexin promotes the localization of SHIP2 at the periphery of the cells leaving its catalytic site intact. The complex formation between Vinexin and SHIP2 may increase cellular adhesion. The data reinforce the concept that SHIP2 is active both as a PtdIns(3,4,5)P3 5-phosphatase and as a modulator of focal contact formation.
authors.affiliation: Interdisciplinary Research Institute (IRIBHM), Université Libre de Bruxelles, Brussels, Belgium.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Paternotte
authors.forename: Jing
authors.initials: J
authors.lastname: Zhang
authors.forename: Isabelle
authors.initials: I
authors.lastname: Vandenbroere
authors.forename: Katrien
authors.initials: K
authors.lastname: Backers
authors.forename: Daniel
authors.initials: D
authors.lastname: Blero
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Kioka
authors.forename: Jean-Marie
authors.initials: JM
authors.lastname: Vanderwinden
authors.forename: Isabelle
authors.initials: I
authors.lastname: Pirson
authors.forename: Christophe
authors.initials: C
authors.lastname: Erneux
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D019556:COS Cells; D002448:Cell Adhesion / Q000502:physiology; D002478:Cells, Cultured; D002522:Chlorocebus aethiops; D003599:Cytoskeleton / Q000378:metabolism*; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D009124:Muscle Proteins / Q000235:genetics / Q000378:metabolism*; D000072183:Phosphatidylinositol-3,4,5-Trisphosphate 5-Phosphatases; D010744:Phosphoric Monoester Hydrolases / Q000235:genetics / Q000378:metabolism*; D011392:Proline / Q000378:metabolism; D011485:Protein Binding; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D020798:Two-Hybrid System Techniques; D018909:src Homology Domains; D048868:Adaptor Proteins, Signal Transducing
chemical_list: D009124:Muscle Proteins; D000072183:Phosphatidylinositol-3,4,5-Trisphosphate 5-Phosphatases; D010744:Phosphoric Monoester Hydrolases; D011392:Proline; D020033:Protein Isoforms; C117452:Sorbs3 protein, mouse; D048868:Adaptor Proteins, Signal Transducing; C096024:phosphatidylinositol-3,4,5-trisphosphate 5-phosphatase; C098706:INPPL1 protein, human