title: Activation of gp130 transduces hypertrophic signal through interaction of scaffolding/docking protein Gab1 with tyrosine phosphatase SHP2 in cardiomyocytes.
abstract: Grb2-associated binder-1 (Gab1) is a scaffolding/docking protein and contains a Pleckstrin homology domain and potential binding sites for Src homology (SH) 2 and SH3 domains. Gab1 is tyrosine phosphorylated and associates with protein tyrosine phosphatase SHP2 and p85 phosphatidylinositol 3-kinase on stimulation with various cytokines and growth factors, including interleukin-6. We previously demonstrated that interleukin-6-related cytokine, leukemia inhibitory factor (LIF), induced cardiac hypertrophy through gp130. In this study, we report the role of Gab1 in gp130-mediated cardiac hypertrophy. Stimulation with LIF induced tyrosine phosphorylation of Gab1, and phosphorylated Gab1 interacted with SHP2 and p85 in cultured cardiomyocytes. We constructed three kinds of adenovirus vectors, those carrying wild-type Gab1 (AdGab1WT), mutated Gab1 lacking SHP2 binding site (AdGab1F627/659), and beta-galactosidase (Adbeta-gal). Compared with cardiomyocytes infected with Adbeta-gal, longitudinal elongation of cardiomyocytes induced by LIF was enhanced in cardiomyocytes infected with AdGab1WT but inhibited in cardiomyocytes infected with AdGab1F627/659. Upregulation of BNP mRNA expression by LIF was evoked in cardiomyocytes infected with Adbeta-gal and AdGab1WT but not in cardiomyocytes infected with AdGab1F627/659. In contrast, Gab1 repressed skeletal alpha-actin mRNA expression through interaction with SHP2. Furthermore, activation of extracellular signal-regulated kinase 5 (ERK5) was enhanced in cardiomyocytes infected with AdGab1WT compared with cardiomyocytes infected with Adbeta-gal but repressed in cardiomyocytes infected with AdGab1F627/659. Coinfection of AdGab1WT with adenovirus vector carrying dominant-negative ERK5 abrogated longitudinal elongation of cardiomyocytes induced by LIF. Taken together, these findings indicate that Gab1-SHP2 interaction plays a crucial role in gp130-dependent longitudinal elongation of cardiomyoctes through activation of ERK5.
authors.affiliation: Department of Molecular Medicine, Osaka University Graduate School of Medicine, 2-2, Yamadaoka, Suita City, Osaka, 565-0871, Japan.
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Nakaoka
authors.forename: Keigo
authors.initials: K
authors.lastname: Nishida
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Fujio
authors.forename: Masahiro
authors.initials: M
authors.lastname: Izumi
authors.forename: Kazuo
authors.initials: K
authors.lastname: Terai
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Oshima
authors.forename: Shoko
authors.initials: S
authors.lastname: Sugiyama
authors.forename: Satoshi
authors.initials: S
authors.lastname: Matsuda
authors.forename: Shigeo
authors.initials: S
authors.lastname: Koyasu
authors.forename: Keiko
authors.initials: K
authors.lastname: Yamauchi-Takihara
authors.forename: Toshio
authors.initials: T
authors.lastname: Hirano
authors.forename: Ichiro
authors.initials: I
authors.lastname: Kawase
authors.forename: Hisao
authors.initials: H
authors.lastname: Hirota
mesh_terms: D000199:Actins / Q000235:genetics; D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D015703:Antigens, CD / Q000378:metabolism*; D009320:Atrial Natriuretic Factor / Q000235:genetics; D001665:Binding Sites / Q000235:genetics; D006332:Cardiomegaly / Q000209:etiology / Q000378:metabolism*; D002478:Cells, Cultured; D050822:Cytokine Receptor gp130; D005786:Gene Expression Regulation / Q000187:drug effects; D017930:Genes, Reporter; D005822:Genetic Vectors; D006131:Growth Inhibitors / Q000494:pharmacology; D015850:Interleukin-6; D047908:Intracellular Signaling Peptides and Proteins; D053605:Leukemia Inhibitory Factor; D008222:Lymphokines / Q000494:pharmacology; D008562:Membrane Glycoproteins / Q000378:metabolism*; D048054:Mitogen-Activated Protein Kinase 7; D020928:Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism; D032383:Myocytes, Cardiac / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D020097:Natriuretic Peptide, Brain; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D011485:Protein Binding / Q000187:drug effects / Q000502:physiology; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D017027:Protein Tyrosine Phosphatases / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D015398:Signal Transduction / Q000187:drug effects; D014162:Transfection
chemical_list: D000199:Actins; D015703:Antigens, CD; C490896:Gab1 protein, rat; D006131:Growth Inhibitors; C494201:Il6st protein, rat; D015850:Interleukin-6; D047908:Intracellular Signaling Peptides and Proteins; D053605:Leukemia Inhibitory Factor; D008222:Lymphokines; D008562:Membrane Glycoproteins; D010750:Phosphoproteins; D012333:RNA, Messenger; D020097:Natriuretic Peptide, Brain; D050822:Cytokine Receptor gp130; D009320:Atrial Natriuretic Factor; D019869:Phosphatidylinositol 3-Kinases; D048054:Mitogen-Activated Protein Kinase 7; D020928:Mitogen-Activated Protein Kinases; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D017027:Protein Tyrosine Phosphatases; C516727:Ptpn11 protein, rat