title: Gab1 is required for cell cycle transition, cell proliferation, and transformation induced by an oncogenic met receptor.
abstract: We have shown previously that either Grb2- or Shc-mediated signaling from the oncogenic Met receptor Tpr-Met is sufficient to trigger cell cycle progression in Xenopus oocytes. However, direct binding of these adaptors to Tpr-Met is dispensable, implying that another Met binding partner mediates these responses. In this study, we show that overexpression of Grb2-associated binder 1 (Gab1) promotes cell cycle progression when Tpr-Met is expressed at suboptimal levels. This response requires that Gab1 possess an intact Met-binding motif, the pleckstrin homology domain, and the binding sites for phosphatidylinositol 3-kinase and tyrosine phosphatase SHP-2, but not the Grb2 and CrkII/phospholipase Cgamma binding sites. Importantly, we establish that Gab1-mediated signals are critical for cell cycle transition promoted by the oncogenic Met and fibroblast growth factor receptors, but not by progesterone, the natural inducer of cell cycle transition in Xenopus oocytes. Moreover, Gab1 is essential for Tpr-Met-mediated morphological transformation and proliferation of fibroblasts. This study provides the first evidence that Gab1 is a key binding partner of the Met receptor for induction of cell cycle progression, proliferation, and oncogenic morphological transformation. This study identifies Gab1 and its associated signaling partners as potential therapeutic targets to impair proliferation or transformation of cancer cells in human malignancies harboring a deregulated Met receptor.
authors.affiliation: Laboratory of Protein Dynamics and Signaling, National Cancer Institute-Frederick, Frederick, MD 21702, USA.
authors.forename: Kathleen
authors.initials: K
authors.lastname: Mood
authors.forename: Caroline
authors.initials: C
authors.lastname: Saucier
authors.forename: Yong-Sik
authors.initials: YS
authors.lastname: Bong
authors.forename: Hyun-Shik
authors.initials: HS
authors.lastname: Lee
authors.forename: Morag
authors.initials: M
authors.lastname: Park
authors.forename: Ira O
authors.initials: IO
authors.lastname: Daar
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002453:Cell Cycle; D049109:Cell Proliferation; D002471:Cell Transformation, Neoplastic; D002478:Cells, Cultured; D017124:Conserved Sequence; D004789:Enzyme Activation / Q000187:drug effects; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D008969:Molecular Sequence Data; D050490:Oncogene Protein tpr-met / Q000494:pharmacology; D009865:Oocytes / Q000166:cytology / Q000187:drug effects; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D010750:Phosphoproteins / Q000737:chemistry / Q000378:metabolism*; D011374:Progesterone / Q000494:pharmacology; D017434:Protein Structure, Tertiary; D021381:Protein Transport / Q000187:drug effects; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D017027:Protein Tyrosine Phosphatases / Q000378:metabolism; D019859:Proto-Oncogene Proteins c-met / Q000378:metabolism*; D017468:Receptors, Fibroblast Growth Factor / Q000378:metabolism
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D047908:Intracellular Signaling Peptides and Proteins; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases; D050490:Oncogene Protein tpr-met; D019869:Phosphatidylinositol 3-Kinases; D010750:Phosphoproteins; D011374:Progesterone; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D017027:Protein Tyrosine Phosphatases; D019859:Proto-Oncogene Proteins c-met; D017468:Receptors, Fibroblast Growth Factor; C490897:Gab1 protein, mouse; C516724:PTPN11 protein, human; C516725:Ptpn11 protein, mouse