mitogen-activated protein kinase kinase kinase kinase 4(MAP4K4) Homo sapiens The protein encoded by this gene is a member of the serine/threonine protein kinase family. This kinase has been shown to specifically activate MAPK8/JNK. The activation of MAPK8 by this kinase is found to be inhibited by the dominant-negative mutants of MAP3K7/TAK1, MAP2K4/MKK4, and MAP2K7/MKK7, which suggests that this kinase may function through the MAP3K7-MAP2K4-MAP2K7 kinase cascade, and mediate the TNF-alpha signaling pathway. Alternatively spliced transcript variants encoding different isoforms have been identified. [provided by RefSeq, Jul 2008],catalytic activity:ATP + a protein = ADP + a phosphoprotein.,cofactor:Magnesium.,function:Serine/threonine kinase that may play a role in the response to environmental stress and cytokines such as TNF-alpha. Appears to act upstream of the JUN N-terminal pathway.,PTM:Phosphorylated upon DNA damage, probably by ATM or ATR.,similarity:Belongs to the protein kinase superfamily.,similarity:Belongs to the protein kinase superfamily. STE Ser/Thr protein kinase family. STE20 subfamily.,similarity:Contains 1 CNH domain.,similarity:Contains 1 protein kinase domain.,subunit:Interacts with the SH3 domain of the adapter proteins Nck (By similarity). Binds, via its CNH regulatory domain, to the N-terminal region of SPG3A.,tissue specificity:Appears to be ubiquitous, expressed in all tissue types examined. Isoform 5 appears to be more abundant in the brain, isoform 4 is predominant in the liver, skeletal muscle and placenta.,
