ROCK-1 (Rho-associated coiled coil-containing protein kinase 1) has been found to be a new caspase-3 substrate. ROCK-1 consists of an amino-terminal kinase domain and an inhibitory cysteine/histidine-rich C-terminal domain. During apoptosis, ROCK-1 is cleaved by caspase-3 at the conserved DETD1113/G sequence and its C-terminal inhibitory domain is removed, resulting in deregulated and constitutive kinase activity. The caspase-3 mediated cleavage and activation of ROCK-1 induces phosphorylation of MLC and membrane blebbing, the early events in the execution phase of apoptosis.
