6hmc
STRUCTURE OF PROTEIN KINASE CK2 CATALYTIC SUBUNIT (ISOFORM CK2ALPHA'; CSNK2A2 gene product) IN COMPLEX WITH THE INDENOINDOLE-TYPE INHIBITOR THN27
Structural highlights
Function[CSK22_HUMAN] Catalytic subunit of a constitutively active serine/threonine-protein kinase complex that phosphorylates a large number of substrates containing acidic residues C-terminal to the phosphorylated serine or threonine. Regulates numerous cellular processes, such as cell cycle progression, apoptosis and transcription, as well as viral infection. May act as a regulatory node which integrates and coordinates numerous signals leading to an appropriate cellular response. During mitosis, functions as a component of the p53/TP53-dependent spindle assembly checkpoint (SAC) that maintains cyclin-B-CDK1 activity and G2 arrest in response to spindle damage. Also required for p53/TP53-mediated apoptosis, phosphorylating 'Ser-392' of p53/TP53 following UV irradiation. Can also negatively regulate apoptosis. Phosphorylates the caspases CASP9 and CASP2 and the apoptotic regulator NOL3. Phosphorylation protects CASP9 from cleavage and activation by CASP8, and inhibits the dimerization of CASP2 and activation of CASP8. Regulates transcription by direct phosphorylation of RNA polymerases I, II, III and IV. Also phosphorylates and regulates numerous transcription factors including NF-kappa-B, STAT1, CREB1, IRF1, IRF2, ATF1, SRF, MAX, JUN, FOS, MYC and MYB. Phosphorylates Hsp90 and its co-chaperones FKBP4 and CDC37, which is essential for chaperone function. Regulates Wnt signaling by phosphorylating CTNNB1 and the transcription factor LEF1. Acts as an ectokinase that phosphorylates several extracellular proteins. During viral infection, phosphorylates various proteins involved in the viral life cycles of EBV, HSV, HBV, HCV, HIV, CMV and HPV.[1] [2] [3] Publication Abstract from PubMedCK2alpha and CK2alpha' are the two isoforms of the catalytic subunit of human protein kinase CK2, an important target for cancer therapy. They have similar, albeit not identical functional and structural properties, and were occasionally reported to be inhibited with distinct efficacies by certain ATP-competitive ligands. Here, we present THN27, an indeno[1,2-b]indole derivative, as a further inhibitor with basal isoform selectivity. The selectivity disappears when measured using CK2alpha/CK2alpha' complexes with CK2beta, the regulatory CK2 subunit. Co-crystal structures of THN27 with CK2alpha and CK2alpha' reveal that subtle differences in the conformational variability of the interdomain hinge region are correlated with the observed effect. In the case of CK2alpha', a crystallographically problematic protein so far, this comparative structural analysis required the development of an experimental strategy that finally enables atomic resolution structure determinations with ab initio phasing of potentially any ATP-competitive CK2 inhibitor and possibly many non-ATP-competitive ligands as well bound to CK2alpha'. Diacritic Binding of an Indenoindole Inhibitor by CK2alpha Paralogs Explored by a Reliable Path to Atomic Resolution CK2alpha' Structures.,Lindenblatt D, Nickelsen A, Applegate VM, Hochscherf J, Witulski B, Bouaziz Z, Marminon C, Bretner M, Le Borgne M, Jose J, Niefind K ACS Omega. 2019 Mar 19;4(3):5471-5478. doi: 10.1021/acsomega.8b03415. eCollection, 2019 Mar 31. PMID:31559376[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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