Catalytic domain of the Serine/Threonine Kinase, Homeodomain-Interacting Protein Kinase 3
STKs catalyze the transfer of the gamma-phosphoryl group from ATP to serine/threonine residues on protein substrates. HIPK3 is a Fas-interacting protein that induces FADD (Fas-associated death domain) phosphorylation and mediates FasL-induced JNK activation. Overexpression of HIPK3 does not affect cell death, however its expression in prostate cancer cells contributes to increased resistance to Fas receptor-mediated apoptosis. HIPK3 also plays a role in regulating steroidogenic gene expression. In response to cAMP, HIPK3 activates the phosphorylation of JNK and c-Jun, leading to increased activity of the transcription factor SF-1 (Steroidogenic factor 1), a key regulator for steroid biosynthesis in the gonad and adrenal gland. 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 HIPK3 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 (PI3K).
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
Jiyao W et al.(2023). "The conserved domain database in 2023.",