Several proteins involved in regulating and executing programmed cell death have been identified in C. elegans. CED-3, a member of the ICE protease/caspase family, and CED-4, a homolog of the mammalian Apaf-1, promote apoptosis. CED-9, a homolog of the mammalian Bcl-2 protein, inhibits cell death. EGL-1 and CED-6 both function as death-promoting proteins, with CED-6 playing a role in the engulfment of apoptotic cells. CED-5 and CED-7 are C. elegans orthologs of the mammalian DOCK180 and ABC transporter proteins, respectively, and also play a role in the engulfment of dying cells.