title: Identification of ILK as a new partner of the ADAM12 disintegrin and metalloprotease in cell adhesion and survival.
abstract: Based on its shedding and binding activities, the disintegrin and metalloprotease 12 (ADAM12) has been implicated in cell signaling. Here we investigate the intracellular protein interaction network of the transmembrane ADAM12L variant using an integrative approach. We identify the integrin-linked kinase (ILK) as a new partner for ADAM12L cellular functions. We demonstrate that ADAM12L coimmunoprecipitates with ILK in cells and that its cytoplasmic tail is required for this interaction. In human cultured hepatic stellate cells (HSCs), which express high levels of endogenous ADAM12L and ILK, the two proteins are redistributed to focal adhesions upon stimulation of a β1 integrin-dependent pathway. We show that down-regulation of ADAM12L in HSCs leads to cytoskeletal disorganization and loss of adhesion. Conversely, up-regulation of ADAM12L induces the Akt Ser-473 phosphorylation-dependent survival pathway via stimulation of β1 integrins and activation of phosphoinositide 3-kinase (PI3K). Depletion of ILK inhibits this effect, which is independent of ADAM12L proteolytic activity and involves its cytoplasmic domain. We further demonstrate that overexpression of ADAM12L promotes kinase activity from ILK immunoprecipitates. Our data suggest a new role for ADAM12L in mediating the functional association of ILK with β1 integrin to regulate cell adhesion/survival through a PI3K/Akt signaling pathway.
authors: Institut National de la Santé et de la Recherche Médicale, UMR1085, Institut de Recherche en Santé, Environnement et Travail, Université de Rennes 1, 35043 Rennes, France.
authors: Anthony
authors: A
authors: Leyme
authors: Katia
authors: K
authors: Bourd-Boittin
authors: Dominique
authors: D
authors: Bonnier
authors: Anaïs
authors: A
authors: Falconer
authors: Yannick
authors: Y
authors: Arlot-Bonnemains
authors: Nathalie
authors: N
authors: Théret
mesh_terms: D051722:ADAM Proteins / Q000378:metabolism*; D000072199:ADAM12 Protein; D002448:Cell Adhesion; D002465:Cell Movement; D049109:Cell Proliferation; D002470:Cell Survival; D002478:Cells, Cultured; D015536:Down-Regulation; D022001:Focal Adhesions; D055166:Hepatic Stellate Cells / Q000378:metabolism; D006801:Humans; D008565:Membrane Proteins / Q000378:metabolism*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism*; D015398:Signal Transduction; D015854:Up-Regulation; D000099200:Scaffold Protein ILK
chemical_list: D051722:ADAM Proteins; D000072199:ADAM12 Protein; D008565:Membrane Proteins; D019869:Phosphatidylinositol 3-Kinases; D017346:Protein Serine-Threonine Kinases; D051057:Proto-Oncogene Proteins c-akt; D000099200:Scaffold Protein ILK; C000606480:ADAM12 protein, human