Similar products |
MEKK4, MAP3K4, KIAA0213, MAPKKK4, MTK1, Mitogen-activated protein kinase kinase kinase 4, MAP three kinase 1, MAPK/ERK kinase kinase 4, MEKK 4, MEK kinase 4 |
Bio Background |
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. The MEKK4 protein, also called MTK1, 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; it could not 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. Northern blot analysis detected an approximately 6-kb transcript in various human tissues. RT-PCR identified a shorter form of MEKK4 mRNA that lacks 49 codons and is probably generated by alternative splicing. |
Bio References |
Luo, W., et al., J. Biol. Chem. 278(39):37451-37458 (2003).Takekawa, M., et al., EMBO J. 16(16):4973-4982 (1997). |