DOK1 mediates SHP-2 binding to the alphaVbeta3 integrin and thereby regulates insulin-like growth factor I signaling in cultured vascular smooth muscle cells.
Recruitment of the Src homology 2 domain tyrosine phosphatase (SHP-2) to the phosphorylated beta3 subunit of the alphaVbeta3 integrin is required for insulin-like growth factor I (IGF-I)-stimulated cell migration and proliferation in vascular smooth muscle cells. Because SHP-2 does not bind directly to beta3, we attempted to identify a linker protein that could mediate SHP-2/beta3 association. DOK1 is a member of insulin receptor substrate protein family that binds beta3 and contains YXXL/I motifs that are potential binding sites for SHP-2. Our results show that IGF-I induces DOK1 binding to beta3 and to SHP-2. Preincubation of cells with synthetic peptides that blocked either DOK1/beta3 or DOK1/SHP-2 association inhibited SHP-2 recruitment to beta3. Expression of a DOK1 mutant that does not bind to beta3 also disrupts SHP-2/beta3 association. As a result of SHP-2/beta3 disruption, IGF-I dependent phosphorylation of Akt and p44/p42 mitogen-activated protein kinase and its ability to stimulate cell migration and proliferation were significantly impaired. These results demonstrate that DOK1 mediates SHP-2/beta3 association in response to IGF-I thereby mediating the effect of integrin ligand occupancy on IGF-IR-linked signaling in smooth muscle cells.
Ling
Yan
Y
University of North Carolina, School of Medicine, Chapel Hill, North Carolina 27599, USA.
Maile
Laura A
LA
Badley-Clarke
Jane
J
Clemmons
David R
DR
D000818:Animals; D000943:Antigens, Differentiation / Q000378:metabolism; D001011:Aorta / Q000166:cytology; D002455:Cell Division / Q000502:physiology; D002465:Cell Movement / Q000502:physiology; D002478:Cells, Cultured; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D039302:Integrin alphaVbeta3 / Q000378:metabolism*; D047908:Intracellular Signaling Peptides and Proteins; D008562:Membrane Glycoproteins / Q000378:metabolism; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000378:metabolism*; D016296:Mutagenesis; D039842:Neural Cell Adhesion Molecule L1 / Q000378:metabolism; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D017027:Protein Tyrosine Phosphatases / Q000378:metabolism*; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D011971:Receptors, Immunologic / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology; D013552:Swine
D000943:Antigens, Differentiation; D004268:DNA-Binding Proteins; C489560:DOK1 protein, human; D039302:Integrin alphaVbeta3; D047908:Intracellular Signaling Peptides and Proteins; D008562:Membrane Glycoproteins; D039842:Neural Cell Adhesion Molecule L1; D010750:Phosphoproteins; D011518:Proto-Oncogene Proteins; D016601:RNA-Binding Proteins; D011971:Receptors, Immunologic; D007334:Insulin-Like Growth Factor I; C494918:AKT1 protein, human; D017346:Protein Serine-Threonine Kinases; D051057:Proto-Oncogene Proteins c-akt; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; C516724:PTPN11 protein, human; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D017027:Protein Tyrosine Phosphatases