Catalytic domain of the Serine/Threonine Kinase, p38beta Mitogen-Activated Protein Kinase (also called MAPK11)
STKs catalyze the transfer of the gamma-phosphoryl group from ATP to serine/threonine residues on protein substrates. p38beta/MAPK11 is widely expressed in tissues and shows more similarity with p38alpha than with the other isoforms. Both are sensitive to pyridinylimidazoles and share some common substrates such as MAPK activated protein kinase 2 (MK2) and the transcription factors ATF2, c-Fos and, ELK-1. p38beta is involved in regulating the activation of the cyclooxygenase-2 promoter and the expression of TGFbeta-induced alpha-smooth muscle cell actin. p38 kinases are mitogen-activated protein kinases (MAPKs), serving as important mediators of cellular responses to extracellular signals. They are activated by the MAPK kinases MKK3 and MKK6, which in turn are activated by upstream MAPK kinase kinases including TAK1, ASK1, and MLK3, in response to cellular stresses or inflammatory cytokines. The p38beta subfamily is part of a larger superfamily that includes the catalytic domains of other STKs, protein tyrosine kinases, RIO kinases, aminoglycoside phosphotransferase, choline kinase, and phosphoinositide 3-kinase.