cd06634: STKc_TAO2 (this model, PSSM-Id:132965 is obsolete and has been replaced by 270804)
Catalytic domain of the Protein Serine/Threonine Kinase, Thousand-and-one amino acids 2
Serine/threonine kinases (STKs), thousand-and-one amino acids 2 (TAO2) subfamily, catalytic (c) domain. STKs catalyze the transfer of the gamma-phosphoryl group from ATP to serine/threonine residues on protein substrates. The TAO 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. TAO proteins possess mitogen-activated protein kinase (MAPK) kinase kinase (MAPKKK or MAP3K or MKKK) activity. MAPK signaling cascades are important in mediating cellular responses to extracellular signals. Human TAO2 is also known as prostate-derived Ste20-like kinase (PSK) and was identified in a screen for overexpressed RNAs in prostate cancer. TAO2 activates both p38 and c-Jun N-terminal kinase (JNK), by phosphorylating and activating the respective MAP/ERK kinases (MEKs, also known as MKKs or MAPKKs), MEK3/MEK6 and MKK4/MKK7. TAO2 contains a long C-terminal extension with autoinhibitory segments. It is activated by the release of this inhibition and the phosphorylation of its activation loop serine. TAO2 functions as a regulator of actin cytoskeletal and microtubule organization. In addition, it regulates the transforming growth factor-activated kinase 1 (TAK1), which is a MAPKKK that plays an essential role in the signaling pathways of tumor necrosis factor (TNF), interleukin 1 (IL-1), and Toll-like receptor (TLR).