Catalytic domain of Extracellular signal-Regulated Kinase 1 and 2-like Serine/Threonine Kinases
STKs catalyze the transfer of the gamma-phosphoryl group from ATP to serine/threonine residues on protein substrates. This subfamily is composed of the mitogen-activated protein kinases (MAPKs) ERK1, ERK2, baker's yeast Fus3, and similar proteins. MAPK pathways are important mediators of cellular responses to extracellular signals. ERK1/2 activation is preferentially by mitogenic factors, differentiation stimuli, and cytokines, through a kinase cascade involving the MAPK kinases MEK1/2 and a MAPK kinase kinase from the Raf family. ERK1/2 have numerous substrates, many of which are nuclear and participate in transcriptional regulation of many cellular processes. They regulate cell growth, cell proliferation, and cell cycle progression from G1 to S phase. Although the distinct roles of ERK1 and ERK2 have not been fully determined, it is known that ERK2 can maintain most functions in the absence of ERK1, and that the deletion of ERK2 is embryonically lethal. The MAPK, Fus3, regulates yeast mating processes including mating-specific gene expression, G1 arrest, mating projection, and cell fusion. This ERK1/2-like 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.",