Mitogen Activated Protein Kinase Kinase Kinase 13 (MAP3K13)

The Mitogen Activated Protein Kinase Kinase Kinase 13 (MAP3K13) catalytic domain has features of both serine/threonine PKs and tyrosine PKs. MAP3K13 shares 86.4% amino acid identity with MAP3K12 , a mixed-lineage kinase. Northern blot analysis detected 9.5-, 8.7-, and 6.5-kb MAP3K13 transcripts most strongly in pancreas. These transcripts were also expressed strongly in brain, liver, and placenta, but no expression was detected in heart, lung, skeletal muscle, and kidney. Immunoblot analysis demonstrated that MAP3K13 is expressed as a 135- to 150-kD protein that is associated with membrane components. Functional analysis showed that MAP3K13 has serine/threonine kinase activity and that it activates the stress-activated PK JNK1 pathway.