The protein encoded by this gene is a member of the serine/threonine kinase family. This kinase has been shown to activate MAPK8/JNK and MKK4/SEK1, and this kinase itself can be phoshorylated, and thus activated by JNK kinases. This kinase functions preferentially on the JNK signaling pathway, and is reported to be involved in nerve growth factor (NGF) induced neuronal apoptosis. [provided by RefSeq, Jul 2008].