Identification and characterization of CPP32/Mch2 homolog l, a novel cysteine protease similar to CPP32

Abstract

We have identified and characterized a novel cysteine protease named CMH-1 that is a new member of the interleukin 1β converting enzyme (ICE) family of proteases with substrate specificity for Asp-X. CMW-1 has the highest similarity to CPP32 (52% amino acid identity) and MCH2 (31% identical). CMH-1 shares conserved amino acid residues that form the core structure of ICE as well as those residues involved in catalysis and in the Pl aspartate binding. Overexpression of CMH-1 in COS cells resulted in the processing of CMH-1 and the induction of apoptosis of transfected cells. Coexpression of CMH-1 with poly(ADP-ribose) polymerase (PARP) also resulted in a specific cleavage of PARP. Purified recombinant CMH-1 cleaved PARP but not interleukin 1β precursor in vitro.