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N-terminal catalytic domain of the Serine/Threonine Kinase, Mitogen and stress-activated kinase 1 STKs catalyze the transfer of the gamma-phosphoryl group from ATP to serine/threonine residues on protein substrates. MSK1 plays a role in the regulation of translational control and transcriptional activation. It phosphorylates the transcription factors, CREB and NFkB. It also phosphorylates the nucleosomal proteins H3 and HMG-14. Increased phosphorylation of MSK1 is associated with the development of cerebral ischemic/hypoxic preconditioning. MSKs contain an N-terminal kinase domain (NTD) from the AGC family and a C-terminal kinase domain (CTD) from the CAMK family. MSKs are activated by two major signaling cascades, the Ras-MAPK and p38 stress kinase pathways, which trigger phosphorylation in the activation loop (A-loop) of the CTD of MSK. The active CTD phosphorylates the hydrophobic motif (HM) of NTD, which facilitates the phosphorylation of the A-loop and activates the NTD, which in turn phosphorylates downstream targets. The MSK1 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. |
Jiyao W et al.(2023). "The conserved domain database in 2023.",