MAP3K4 Antibody – Rabbit

The central core of each mitogen-activated protein kinase (MAPK) pathway is a conserved cascade of 3 protein kinases: an activated MAPK kinase kinase (MAPKKK) phosphorylates and activates a specific MAPK kinase (MAPKK), which then activates a specific MAPK. While the ERK MAPKs are activated by mitogenic stimulation, the CSBP2 and JNK MAPKs are activated by environmental stresses such as osmotic shock, UV irradiation, wound stress, and inflammatory factors. This gene encodes a MAPKKK, the MEKK4 protein, also called MTK1. This protein contains a protein kinase catalytic domain at the C terminus. The N-terminal nonkinase domain may contain a regulatory domain. Expression of MEKK4 in mammalian cells activated the CSBP2 and JNK MAPK pathways, but not the ERK pathway. In vitro kinase studies indicated that recombinant MEKK4 can specifically phosphorylate and activate PRKMK6 and SERK1, MAPKKs that activate CSBP2 and JNK, respectively but cannot phosphorylate PRKMK1, an MAPKK that activates ERKs. MEKK4 is a major mediator of environmental stresses that activate the CSBP2 MAPK pathway, and a minor mediator of the JNK pathway. Two alternatively spliced transcripts encoding distinct isoforms have been described. [provided by RefSeq, Jul 2008]

MEKK4: a protein kinase of the STE11 family. A mediator of environmental stresses. Phosphorylates and activates MKK4, -6, and-7, which in turn activate the p38 AND JNK MAPK pathways.

Protein type: Protein kinase, STE; EC 2.7.11.25; Kinase, protein; Protein kinase, Ser/Thr (non-receptor); STE group; STE11 family

Chromosomal Location of Human Ortholog: 6q26

Cellular Component: perinuclear region of cytoplasm; cytoplasm

Molecular Function: MAP kinase kinase activity; protein binding; MAP kinase kinase kinase activity; metal ion binding; ATP binding

Biological Process: positive regulation of JNK activity; activation of MAPKK activity; activation of MAPK activity; regulation of gene expression; MAPKKK cascade; protein amino acid phosphorylation; response to UV-C; placenta development; male germ-line sex determination