3war | pdb_00003war
Crystal structure of human CK2a
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 PubMedThe Ser/Thr kinase CK2 consists of two catalytic subunits (CK2alpha) and a dimer of the regulatory subunits (CK2beta), and is a ubiquitous enzyme that regulates growth, proliferation and the survival of cells. CK2 is a remarkable drug target for potentially treating a wide variety of tumours and glomerulonephritis. The purified CK2alpha protein was crystallized using ethylene glycol as a precipitant. The crystal structure of CK2alpha with 21 loci of alternative conformations, including a niacin, 19 ethylene glycols and 346 waters, was determined at 1.06 A resolution to an Rwork of 14.0% (Rfree = 16.5%). The alternative ensemble in the internal hydrophobic core underpins the plasticity of the alphaD-helix responsible for the regulation of ATP/GTP binding. The clear density map indicates that a niacin molecule, contained in the Escherichia coli culture medium, binds to the ATP binding site. An ethylene glycol molecule binds in the hydrophobic pocket lateral to the alphaD-helix forming the rim of the active site. The other ethylene glycol molecules occupy physiologically significant sites, including the CK2beta binding interface and substrate binding site, as well as the gap in the crystal packing. Together with water molecules in the active site, these structural insights should facilitate drug discovery. Crystal structure of human CK2alpha at 1.06 A resolution.,Kinoshita T, Nakaniwa T, Sekiguchi Y, Sogabe Y, Sakurai A, Nakamura S, Nakanishi I J Synchrotron Radiat. 2013 Nov;20(Pt 6):974-9. doi: 10.1107/S0909049513020785., Epub 2013 Oct 2. PMID:24121351[5] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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