Apoptosis is mediated by death domain (DD) and/or caspase recruitment domain (CARD) containing molecules and a caspase family of proteases. DD-containing serine/threonine kinase RIP regulates Fas-induced apoptosis. A novel CARD-containing serine/threonine kinase was recently identified and designated RICK/RIP2/CARDIAK for RIP-like interacting CLARP kinase, receptor interacting protein-2, and CARD-containing ICE associated kinase, respectively. RICK contains an N-terminal kinase catalytic domain and a C-terminal CARD domain. Overexpression of RICK induced apoptosis and activation of NF-kappaB and JNK. RICK interacts with members of the TRAF family, CLARP and caspase-1. Thus, RICK represents a novel kinase that regulates TNF and Fas induced-apoptosis and that is involved in the generation of proinflammatory cytokine IL-1beta. The messenger RNA of RICK is expressed in multiple human tissues.