title: Role of the docking protein Gab2 in beta(1)-integrin signaling pathway-mediated hematopoietic cell adhesion and migration.
abstract: Gab2, a newly identified pleckstrin homology domain-containing docking protein, is a major binding protein of SHP-2 tyrosine phosphatase in interleukin (IL)-3-stimulated hematopoietic cells. Its signaling mechanism remains largely unknown. We report here an important regulatory role for Gab2 in beta(1) integrin signaling pathway that mediates hematopoietic cell adhesion and migration. Cross-linking of the beta(1) integrin on Ba/F3 cells induced rapid tyrosine phosphorylation of Gab2 and its association with Syk kinase, SHP-2 phosphatase, and the p85 subunit of phosphatidylinositol (PI)-3 kinase. In addition, Gab2 was also constitutively associated with SHP-1 phosphatase via its C-terminal Src homology 2 domain. Overexpression of the pleckstrin homology domain or a mutant Gab2 molecule lacking SHP-2 binding sites resulted in significant reductions in Ba/F3 cell adhesion and migration. Biochemical analyses revealed that enforced expression of Gab2 mutant molecules dramatically reduced beta(1)-integrin ligation-triggered PI3 kinase activation, whereas Erk kinase activation remained unaltered. Furthermore, transduction of primary hematopoietic progenitor cells from viable motheaten mice with these mutant Gab2 molecules also significantly ameliorated their enhanced migration capacity associated with the SHP1 gene mutation. Taken together, these results suggest an important signaling role for Gab2 in regulating hematopoietic cell adhesion and migration.
authors.affiliation: Department of Hematopoiesis, Jerome H. Holland Laboratory for the Biomedical Sciences, American Red Cross, 15601 Crabbs Branch Way, Rockville, MD 20855, USA.
authors.forename: Wen-Mei
authors.initials: WM
authors.lastname: Yu
authors.forename: Teresa S
authors.initials: TS
authors.lastname: Hawley
authors.forename: Robert G
authors.initials: RG
authors.lastname: Hawley
authors.forename: Cheng-Kui
authors.initials: CK
authors.lastname: Qu
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D001854:Bone Marrow Cells / Q000166:cytology / Q000502:physiology; D002448:Cell Adhesion; D002460:Cell Line; D002465:Cell Movement; D004792:Enzyme Precursors / Q000378:metabolism; D005786:Gene Expression Regulation; D006412:Hematopoietic Stem Cells / Q000502:physiology*; D019012:Integrin beta1 / Q000502:physiology*; D047908:Intracellular Signaling Peptides and Proteins; D051379:Mice; D008810:Mice, Inbred C57BL; D008817:Mice, Mutant Strains; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D010750:Phosphoproteins / Q000235:genetics / Q000502:physiology*; D010766:Phosphorylation; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; D017027:Protein Tyrosine Phosphatases / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D054593:SH2 Domain-Containing Protein Tyrosine Phosphatases; D015398:Signal Transduction / Q000502:physiology*; D000072377:Syk Kinase; D014162:Transfection; D018909:src Homology Domains
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D004792:Enzyme Precursors; D019012:Integrin beta1; D047908:Intracellular Signaling Peptides and Proteins; D019869:Phosphatidylinositol 3-Kinases; D010750:Phosphoproteins; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; D017027:Protein Tyrosine Phosphatases; D011505:Protein-Tyrosine Kinases; D054593:SH2 Domain-Containing Protein Tyrosine Phosphatases; D000072377:Syk Kinase; C490894:Gab2 protein, mouse; C000606897:Syk protein, mouse; C516725:Ptpn11 protein, mouse; C509248:Ptpn6 protein, mouse