Catalytic domain of the Serine/Threonine Kinase, Homeodomain-Interacting Protein Kinase 1
STKs catalyze the transfer of the gamma-phosphoryl group from ATP to serine/threonine residues on protein substrates. HIPK1 has been implicated in regulating eye size, lens formation, and retinal morphogenesis during late embryogenesis. It also contributes to the regulation of haematopoiesis and leukaemogenesis by phosphorylating and repressing the transcription factor c-Myb, which is crucial in T- and B-cell development. In glucose-deprived conditions, HIPK1 phosphorylates Daxx, leading to its relocalization from the nucleus to the cytoplasm, where it binds and stabilizes ASK1 (apoptosis signal-regulating kinase 1), a mitogen-activated protein kinase (MAPK) kinase kinase that activates the JNK and p38 MAPK pathways. HIPKs, originally identified by their ability to bind homeobox factors, are nuclear proteins containing catalytic kinase and homeobox-interacting domains as well as a PEST region overlapping with the speckle-retention signal (SRS). The HIPK1 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.
Comment:includes ATP binding and substrate binding sites
Comment:based on the structures of human CDK2 and DYRK1A bound with ATP or inhibitor and substrate peptides, and on the structures of other CMGC kinases, bound with ATP or ATP analogs
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