Gab1 is an integrator of cell death versus cell survival signals in oxidative stress.
Upon the addition of different growth factors and cytokines, the Gab1 docking protein is tyrosine phosphorylated and in turn activates different signaling pathways. On the basis of the large body of evidence concerning cross talk between the signaling pathways activated by growth factors and oxidative stress, we decided to investigate the role of Gab1 in oxidative injury. We stimulated wild-type mouse embryo fibroblasts (MEF) or MEF with a homozygous deletion of the Gab1 gene (-/- MEF) with H(2)O(2). Our results show that Gab1 is phosphorylated in a dose- and time-dependent manner after H(2)O(2) triggering. Gab1 then recruits molecules such as SHP2, phosphatidylinositol 3-kinase (PI3K), and Shc. Gab1 phosphorylation is sensitive to the Src family kinase inhibitor PP2. Furthermore, we demonstrate that Gab1 is required for H(2)O(2)-induced c-Jun N-terminal kinase (JNK) activation but not for ERK2 or p38 activation. Reconstitution of Gab1 in -/- MEF rescues JNK activation, and we find that this is dependent on the SHP2 binding site in Gab1. Cell viability assays reveal that Gab1 has a dual role in cell survival: a positive one through its interaction with PI3K and a negative one through its interaction with SHP2. This is the first report identifying Gab1 as a component in oxidative stress signaling and one that is required for JNK activation.
Holgado-Madruga
Marina
M
Department of Microbiology and Immunology, Kimmel Cancer Institute, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA. M_Holgado_Madruga@mail.jci.tju.edu
Wong
Albert J
AJ
D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D001665:Binding Sites; D015153:Blotting, Western; D016923:Cell Death; D002460:Cell Line; D002470:Cell Survival; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation; D006367:HeLa Cells; D006720:Homozygote; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D047908:Intracellular Signaling Peptides and Proteins; D048031:JNK Mitogen-Activated Protein Kinases; D051379:Mice; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D008957:Models, Genetic; D018384:Oxidative Stress; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D010750:Phosphoproteins / Q000378:metabolism / Q000502:physiology*; D010766:Phosphorylation; D011233:Precipitin Tests; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D017027:Protein Tyrosine Phosphatases / Q000378:metabolism; D015398:Signal Transduction; D013997:Time Factors; D014162:Transfection; D014407:Tumor Cells, Cultured; D014443:Tyrosine / Q000378:metabolism; D048051:p38 Mitogen-Activated Protein Kinases
D048868:Adaptor Proteins, Signal Transducing; C098587:GAB1 protein, human; C490897:Gab1 protein, mouse; D047908:Intracellular Signaling Peptides and Proteins; D010750:Phosphoproteins; D014443:Tyrosine; D006861:Hydrogen Peroxide; D019869:Phosphatidylinositol 3-Kinases; D048031:JNK Mitogen-Activated Protein Kinases; D019950:Mitogen-Activated Protein Kinase 1; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; C516724:PTPN11 protein, human; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D017027:Protein Tyrosine Phosphatases; C516725:Ptpn11 protein, mouse