Regulation of CDC42 GTPase by proline-rich tyrosine kinase 2 interacting with PSGAP, a novel pleckstrin homology and Src homology 3 domain containing rhoGAP protein.
Proline-rich tyrosine kinase 2 (PYK2), a tyrosine kinase structurally related to focal adhesion kinase (FAK), is implicated in regulating cytoskeletal organization. However, mechanisms by which PYK2 participates in and regulates cytoskeletal organization remain largely unknown. Here we report identification of PSGAP, a novel protein that interacts with PYK2 and FAK and contains multiple domains including a pleckstrin homology domain, a rhoGTPase-activating protein domain, and a Src homology 3 domain. PYK2 interacts with PSGAP Src homology 3 domain via the carboxyl-terminal proline-rich sequence. PSGAP is able to increase GTPase activity of CDC42 and RhoA in vitro and in vivo. Remarkably, PYK2, but not FAK, can activate CDC42 via inhibition of PSGAP-mediated GTP hydrolysis of CDC42. Moreover, PSGAP is localized at cell periphery in fibroblasts in a pleckstrin homology domain-dependent manner. Over expression of PSGAP in fibroblasts results in reorganization of cytoskeletal structures and changes of cellular morphology, which requires rhoGTPase-activating activity. Taken together, our results suggest that PSGAP is a signaling protein essential for PYK2 regulation of cytoskeletal organization via Rho family GTPases.
Department of Pathology and Cell Adhesion and Matrix Center, Pathology, and Physical Medicine and Rehabilitation, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA.
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Ren
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Du
Y Z
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Huang
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Ao
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Mei
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Xiong
D000595:Amino Acid Sequence; D001798:Blood Proteins / Q000737:chemistry*; D002460:Cell Line; D003001:Cloning, Molecular; D003599:Cytoskeleton / Q000378:metabolism; D004789:Enzyme Activation; D005347:Fibroblasts; D051417:Focal Adhesion Kinase 1; D051418:Focal Adhesion Kinase 2; D051416:Focal Adhesion Protein-Tyrosine Kinases; D020690:GTPase-Activating Proteins / Q000737:chemistry* / Q000378:metabolism*; D006801:Humans; D008969:Molecular Sequence Data; D010750:Phosphoproteins / Q000737:chemistry*; D011392:Proline / Q000378:metabolism; D011485:Protein Binding; D021381:Protein Transport; D011505:Protein-Tyrosine Kinases / Q000737:chemistry / Q000378:metabolism*; D016415:Sequence Alignment; D020798:Two-Hybrid System Techniques; D020764:cdc42 GTP-Binding Protein / Q000378:metabolism*; D020931:ran GTP-Binding Protein / Q000378:metabolism; D020742:rhoA GTP-Binding Protein / Q000378:metabolism; D018909:src Homology Domains
C486050:ARHGAP10 protein, human; C115971:ARHGAP26 protein, human; C425467:Arhgap10 protein, mouse; D001798:Blood Proteins; D020690:GTPase-Activating Proteins; D010750:Phosphoproteins; C039077:platelet protein P47; C085379:rho GTPase-activating protein; D011392:Proline; D011505:Protein-Tyrosine Kinases; D051417:Focal Adhesion Kinase 1; D051418:Focal Adhesion Kinase 2; D051416:Focal Adhesion Protein-Tyrosine Kinases; C496050:PTK2 protein, human; D020764:cdc42 GTP-Binding Protein; D020931:ran GTP-Binding Protein; D020742:rhoA GTP-Binding Protein