 In 1994, Michael Hengartner published a paper showing that "ced-9" had similar sequence to "bcl-2".In 1997, a protein similar to CED-4 was identified and named Apaf-1 (apoptotic protease activating factor).The team published their results in an article entitled "Apaf-1, a human protein homologous to C. elegans CED-4, participates in cytochrome c-dependent activation of caspase-3".