ROCK

Rocks are serine/threonine kinases which are involved in cell motility, cell proliferation and apoptosis. The activity of ROCK can be regulated in different ways in different condition. During apoptosis, caspase-3 cleaves the carboxy-terminal region of ROCKs to free the activity of ROCKs. The kinase activity of ROCKs is moderately enhanced after Rho binding. Small GTP-binding proteins, Gem and Rad, function as negative regulators of ROCKs.  ROCKs can phosphorylate LIM kinase, myosin light chain (MLC) and MLC phosphatase to increase actin-filament assembly and actomyosin contraction. In response to sphingosine-1-phosphate (S1P) binding to G-protein-coupled receptors (GPCR), Rho can be activated by guanine nucleotide exchange factors (GEFs) that are themselves activated. ROCK can also influence the insulin signaling pathway to interface cell.