3u9c | pdb_00003u9c
Structure of a C-terminal deletion mutant of human protein kinase CK2 catalytic subunit with the ATP-competitive inhibitor resorufin
Structural highlights
Function[CSK21_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] [4] Publication Abstract from PubMedA low-resolution structure of the catalytic subunit CK2alpha of human protein kinase CK2 (formerly known as casein kinase 2) in complex with the ATP-competitive inhibitor resorufin is presented. The structure supplements previous human CK2alpha structures in which the interdomain hinge/helix alphaD region adopts a closed conformation correlating to a canonically established catalytic spine as is typical for eukaryotic protein kinases. In the corresponding crystal packing the hinge/helix alphaD region is nearly unaffected by crystal contacts, so that largely unbiased conformational adaptions are possible. This is documented by published human CK2alpha structures with the same crystal packing but with an open hinge/helix alphaD region, one of which has been redetermined here with a higher symmetry. An overview of all published human CK2alpha crystal packings serves as the basis for a discussion of the factors that determine whether the open or the closed hinge/helix alphaD conformation is adopted. Lyotropic salts in crystallization support the closed conformation, in which the Phe121 side chain complements the hydrophobic catalytic spine ensemble. Consequently, genuine ligand effects on the hinge/helix alphaD conformation can be best studied under moderate salt conditions. Ligands that stabilize either the open or the closed conformation by hydrogen bonds are known, but a general rule is not yet apparent. Low-density crystal packing of human protein kinase CK2 catalytic subunit in complex with resorufin or other ligands: a tool to study the unique hinge-region plasticity of the enzyme without packing bias.,Klopffleisch K, Issinger OG, Niefind K Acta Crystallogr D Biol Crystallogr. 2012 Aug;68(Pt 8):883-92. Epub 2012 Jul 7. PMID:22868753[5] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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