Amyotrophic lateral sclerosis 2 (juvenile) chromosome region, candidate 2, is connected to transferase/kinase activity and ATP binding, it has recently been shown to interact with XIAP, a member of the IAP (Inhibitor of Apoptosis) protein family. Together, these two proteins synergistically activate the TAK1/JNK1 signal transduction pathway, which acts to protect against the interleukin-1 converting enzyme of Fas-induced apotosis. This protein was independently isolated and characterized as polyploidy-associated protein kinase (PAPK), a member of the Ste20/germinal center kinase family that modulates cytoskeletal organization and cell survival, suggesting that its protective role may be a function of its kinase activity. Although two mRNA sequences have been isolated, only the shorter isoform has been observed.