JUN N-terminal Kinase 2is a member of the MAP kinase family. MAP kinases act as an integration point for multiple biochemical signals, and are involved in a wide variety of cellular processes such as proliferation, differentiation, transcription regulation and development. This kinase targets specific transcription factors, and thus mediates immediate-early gene expression in response to various cell stimuli. It is most closely related to MAPK8, both of which are involved in UV radiation induced apoptosis, thought to be related to the cytochrome c-mediated cell death pathway. This gene and MAPK8 are also known as c-Jun N-terminal kinases. This kinase blocks the ubiquitination of tumor suppressor p53, and thus it increases the stability of p53 in nonstressed cells. Studies of this gene's mouse counterpart suggest a key role in T-cell differentiation. Four alternatively spliced transcript variants encoding distinct isoforms have been reported.
JNK2 is a soluble 51 kDa protein (amino acids 2-424) that is activated in response to cellular stress, radiation and growth factors. JNK2 binds to the amino terminal activation domains of c-jun or ATF2 regulating AP-1 transcriptional activity.