DIP (mDia interacting protein) is a key molecule regulating Rho and Rac in a Src-dependent manner.
Cell movement is driven by the coordinated regulation of cytoskeletal reorganization through Rho GTPases downstream of integrin and growth-factor receptor signaling. We have reported that mDia, a target protein of Rho, interacts with Src and DIP. Here we show that DIP binds to p190RhoGAP and Vav2, and that DIP is phosphorylated by Src and mediates the phosphorylation of p190RhoGAP and Vav2 upon EGF stimulation. When endogenous DIP was inhibited by expressing dominant-negative mutants of DIP or siRNA, phosphorylation of p190RhoGAP and Vav2 upon EGF stimulation was diminished, and EGF-induced actin organization, distribution of p190RhoGAP and Vav2, and cell movement were affected. Therefore, DIP seems to transfer the complex of the three proteins from cytosol to beneath the membrane, and the three proteins, in turn, can be phosphorylated by Src. DIP inactivated Rho and activated Rac following EGF stimulation in the membrane fraction. Thus, DIP acts as a regulatory molecule causing Src kinase-dependent feedback modulation of Rho GTPases downstream of Rho-mDia upon EGF stimulation, and plays an important role in cell motility.
Meng
Wenxiang
W
Department of Cellular and Molecular Physiology, Mie University School of Medicine, Tsu, Japan.
Numazaki
Mitsuko
M
Takeuchi
Kumiko
K
Uchibori
Yoshiari
Y
Ando-Akatsuka
Yuhko
Y
Tominaga
Makoto
M
Tominaga
Tomoko
T
D000818:Animals; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D002465:Cell Movement; D048430:Cell Shape; D002522:Chlorocebus aethiops; D004268:DNA-Binding Proteins; D004789:Enzyme Activation; D004815:Epidermal Growth Factor / Q000494:pharmacology; D020690:GTPase-Activating Proteins; D020662:Guanine Nucleotide Exchange Factors / Q000378:metabolism*; D006801:Humans; D051379:Mice; D009687:Nuclear Proteins / Q000378:metabolism*; D015513:Oncogene Proteins / Q000378:metabolism*; D010766:Phosphorylation; D021381:Protein Transport; D051567:Proto-Oncogene Proteins c-vav; D012097:Repressor Proteins; D022502:Stress Fibers / Q000187:drug effects / Q000502:physiology; D020744:rac GTP-Binding Proteins / Q000378:metabolism*; D020741:rho GTP-Binding Proteins / Q000378:metabolism*; D019061:src-Family Kinases / Q000378:metabolism
C074560:ARHGAP35 protein, human; C513043:ARHGAP5 protein, human; C513041:Arhgap35 protein, mouse; C513042:Arhgap5 protein, mouse; D004268:DNA-Binding Proteins; D020690:GTPase-Activating Proteins; D020662:Guanine Nucleotide Exchange Factors; D009687:Nuclear Proteins; D015513:Oncogene Proteins; D051567:Proto-Oncogene Proteins c-vav; D012097:Repressor Proteins; C093651:VAV2 protein, human; C490565:Vav2 protein, mouse; D004815:Epidermal Growth Factor; D019061:src-Family Kinases; D020744:rac GTP-Binding Proteins; D020741:rho GTP-Binding Proteins