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Catalytic domain of the Serine/Threonine Kinase, Serine-aRginine Protein Kinase 1 STKs catalyze the transfer of the gamma-phosphoryl group from ATP to serine/threonine residues on protein substrates. SRPK1 binds with high affinity the alternative splicing factor, SRSF1 (serine/arginine-rich splicing factor 1), and regiospecifically phosphorylates 10-12 serines in its RS domain. It plays a role in the regulation of pre-mRNA splicing, chromatin structure, and germ cell development. SRPKs phosphorylate and regulate splicing factors from the SR protein family by specifically phosphorylating multiple serine residues residing in SR/RS dipeptide motifs (also known as RS domains). Phosphorylation of the RS domains enhances interaction with transportin SR and facilitates entry of the SR proteins into the nucleus. SRPKs contain a nonconserved insert domain, within the well-conserved catalytic kinase domain, that regulates their subcellular localization. The SRPK 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.",