Figure 2.

Genes involved in the activation and the execution phases of programmed cell death in C. elegans. Genes involved in two critical phases of programmed cell death, (A) activation and (B) execution, are shown. In the execution phase, four cell death execution events (fragmentation and degradation of chromosomal DNA, mitochondrial elimination, engulfment of apoptotic cell corpses, and inactivation of survival signals) are directly activated by the proteolytic cleavage of the CED-3 caspase. Three partially-redundant pathways, colored in pink, red, and green, respectively, mediate recognition and removal of apoptotic cell corpses. The activation of CED-10 and CDC-42 small GTPases leads to cytoskeletal reorganization required for pseudopod extension around an apoptotic cell. Arrows indicate confirmed activation and dashed arrows indicate proposed activation.