cd06651: STKc_MEKK3 (this model, PSSM-Id:132982 is obsolete and has been replaced by 270817)
Catalytic domain of the Protein Serine/Threonine Kinase, MAP/ERK kinase kinase 3
Serine/threonine kinases (STKs), MAP/ERK kinase kinase 3 (MEKK3) subfamily, catalytic (c) domain. STKs catalyze the transfer of the gamma-phosphoryl group from ATP to serine/threonine residues on protein substrates. The MEKK3 subfamily is part of a larger superfamily that includes the catalytic domains of other protein STKs, protein tyrosine kinases, RIO kinases, aminoglycoside phosphotransferase, choline kinase, and phosphoinositide 3-kinase. MEKK3 is a mitogen-activated protein kinase (MAPK) kinase kinase (MAPKKK or MKKK or MAP3K), that phosphorylates and activates the MAPK kinase MEK5 (or MKK5), which in turn phosphorylates and activates extracellular signal-regulated kinase 5 (ERK5). The ERK5 cascade plays roles in promoting cell proliferation, differentiation, neuronal survival, and neuroprotection. MEKK3 plays an essential role in embryonic angiogenesis and early heart development. In addition, MEKK3 is involved in interleukin-1 receptor and Toll-like receptor 4 signaling. It is also a specific regulator of the proinflammatory cytokines IL-6 and GM-CSF in some immune cells. MEKK3 also regulates calcineurin, which plays a critical role in T cell activation, apoptosis, skeletal myocyte differentiation, and cardiac hypertrophy.