Kinase Subfamily JNK

Kinase Classification: Group CMGC: Family MAPK: Subfamily JNK

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Evolution

JNK is seen in all animals, including sponges, but is absent from choanoflagellates and fungi. There are three human members, JNK1, JNK2, JNK3 (aka MAPK8-10), one in Drosopihla (bsk), and 5 in C. elegans.

Domain Structure

Like most MAPK, JNK is made primarily of a kinase domain, most similar to the p38 subfamily, followed by an L16 region shared between many MAPK, and some additional C-terminal unconserved sequences.

Functions

Jnk kinases are activated by MEK (MAPKK, STE7) kinases, which in turn are activated by MEKKs (MAP3K, STE11), and generally transduce stress signals within the cell. Jnks phosphorylate several transcription factors including the AP-1 class factors c-Jun and ATF-2, and Myc, as well as p53, IRS-1 and Bcl-2 family proteins.

In both mammals and Drosophila, Jnk is involved in several stress responses, including oxidative stress, and UV radiation, in control of apoptosis, and has been also implicated both in neuronal development and cancer.