Responds to activation by environmental stress and pro-inflammatory cytokines by phosphorylating a number of transcription factors, primarily components of AP-1 such as JUN, JDP2 and ATF2 and thus regulates AP-1 transcriptional activity. In T-cells, JNK1 and JNK2 are required for polarized differentiation of T-helper cells into Th1 cells. Phosphorylates heat shock factor protein 4 (HSF4).
Specificity
Natural and recombinant Mouse Mitogen-activated protein kinase 8
Binds to at least four scaffolding proteins, MAPK8IP1/JIP-1, MAPK8IP2/JIP-2, MAPK8IP3/JIP-3/JSAP1 and SPAG9/MAPK8IP4/JIP-4. These proteins also bind other components of the JNK signaling pathway. Forms a complex with MAPK8IP1 and RGNEF. Interacts with TP53 and WWOX. Interacts with JAMP. Interacts with NFATC4. Interacts with MECOM; regulates JNK signaling (By similarity). Interacts (phosphorylated form) with NFE2; the interaction phosphorylates NFE2 in undifferentiated cells.