Rho signaling, ROCK and mDia1, in transformation, metastasis and invasion.
The Rho subgroup of the Rho GTPases consisting of RhoA, RhoB and RhoC induces a specific type of actin cytoskeleton and carry out a variety of functions in the cell. mDia and ROCK are downstream effectors of Rho mediating Rho action on the actin cytoskeleton; mDia produces actin filaments by nucleation and polymerization and ROCK activate myosin to cross-link them for induction of actomyosin bundles and contractility. mDia is potentially linked to Rac activation and membrane ruffle formation through c-Src-induced phosphorylation of focal adhesion proteins, and ROCK antagonizes this mDia action. Thus, cell morphogenesis, adhesion, and motility can be determined by the balance between mDia and ROCK activities. Though they are not oncogenes by themselves, overexpression of RhoA and RhoC are often found in clinical cancers, and RhoC has been repeatedly identified as a gene associated with metastasis. The Rho-ROCK pathway is implicated in Ras-mediated transformation, the amoeboid movement of tumor cells in the three-dimensional matrix, and transmigration of tumor cells through the mesothelial monolayer. On the other hand, the Rho-mDia1 pathway is implicated in Src-mediated remodeling of focal adhesions and migration of tumor cells. There is also an indication that the Rho pathway other than ROCK is involved in Src-mediated induction of podosome and regulation of matrix metalloproteases. Thus, Rho mediates various phenotypes of malignant transformation by Ras and Src through its effectors, ROCK and mDia.
Narumiya
Shuh
S
Department of Pharmacology, Kyoto University Faculty of Medicine, Kyoto, 606-8501, Japan. snaru@mfour.med.kyoto-u.ac.jp
Tanji
Masahiro
M
Ishizaki
Toshimasa
T
D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism*; D000818:Animals; D002465:Cell Movement; D002471:Cell Transformation, Neoplastic; D000080865:Formins; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D020782:Matrix Metalloproteinases / Q000378:metabolism; D008954:Models, Biological; D009361:Neoplasm Invasiveness; D009362:Neoplasm Metastasis; D009369:Neoplasms / Q000378:metabolism* / Q000473:pathology*; D015398:Signal Transduction; D054460:rho-Associated Kinases / Q000378:metabolism*; D019061:src-Family Kinases / Q000378:metabolism
D048868:Adaptor Proteins, Signal Transducing; C108962:DIAPH1 protein, human; D000080865:Formins; D019061:src-Family Kinases; D054460:rho-Associated Kinases; D020782:Matrix Metalloproteinases