Insulin/IGF-1-like signaling is well-conserved evolutionarily across animal phyla, from single celled organisms to mammals.[6] DAF-2 is the only member of the insulin receptor family in C. elegans [a nematode] but it corresponds, in form and function, to multiple pathways in humans. The protein predicted from DAF-2's sequence is 35% identical to the human insulin receptor, which regulates metabolism; 34% identical to the IGF-1 receptor, which regulates growth; and 33% identical to the human insulin receptor–related receptor.[7][8] In C. elegans, the insulin/IGF-1/FOXO pathway is initiated by changes in IGF-1 levels which cause IGF-1 receptors to start a phosphorylation cascade that deactivates the FOXO transcription factor, DAF-16. When not phosphorylated, DAF-16 is active and present in the nucleus. DAF-16 is responsible for up-regulating transcription of about 100 genes that code for cell protecting products such as heat shock proteins and antioxidants.[9] Genetic analysis reveals that the presence of functioning DAF-16 is required to produce the extended lifespan observed in DAF-2 knock-downs.[10] By silencing DAF-16, activation of DAF-2 receptors can ultimately compromise a cell’s ability to mitigate harmful environmental conditions.[6] In most eukaryotes, insulin activates DAF-2 signaling. However, both human insulin and insulin coded for by orthologous genes in C. elegans inhibit DAF-2 receptors in C. elegans.[11]