The small GTP binding protein Rho is implicated in cytoskeletal responses to extracellular signals such as lysophosphatidic acid to form stress fibers and focal contacts. Here we have purified a Rho-interacting protein with a molecular mass of ~ 164 kDa (p164) from bovine brain. This protein bound to GTPγS (a non-hydrolyzable GTP analog)·RhoA but not to GDP·RhoA or GTPγS·RhoA with a mutation in the effector domain (RhoA(A37)). p164 had a kinase activity which was specifically stimulated by GTPγS·RhoA. We obtained the cDNA encoding p164 on the basis of its partial amino acid sequences and named it Rho-associated kinase (Rho-kinase). Rho-kinase has a catalytic domain in the N-terminal portion, a coiled coil domain in the middle portion and a zinc finger-like motif in the C-terminal portion. The catalytic domain shares 72% sequence homology with that of myotonic dystrophy kinase and the coiled coil domain contains a Rho-interacting interface. When COS7 cells were co-transfected with Rho-kinase and activated RhoA, some Rho-kinase was recruited to membranes. Thus it is likely that Rho-kinase is a putative target serine/threonine kinase for Rho and serves as a mediator of the Rho-dependent signaling pathway.
|Number of pages||9|
|Publication status||Published - 01-05-1996|
All Science Journal Classification (ASJC) codes
- Molecular Biology
- Biochemistry, Genetics and Molecular Biology(all)
- Immunology and Microbiology(all)