6spw | pdb_00006spw
Structure of protein kinase CK2 catalytic subunit with the CK2beta-competitive bisubstrate inhibitor ARC3140
Structural highlights
FunctionCSK21_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 PubMedProtein kinase CK2, a heterotetrameric holoenzyme composed of two catalytic chains (CK2alpha) attached to a homodimer of regulatory subunits (CK2beta), is a target for drug development for cancer therapy. Here, we describe the tetraiodobenzimidazole derivative ARC-3140, a bisubstrate inhibitor addressing the ATP site and the substrate-binding site of CK2 with extraordinary affinity (Ki = 84 pM). In a crystal structure of ARC-3140 in complex with CK2alpha, three copies of the inhibitor are visible, one of them at the CK2beta interface of CK2alpha. Subsequent interaction studies based on microscale thermophoresis and fluorescence anisotropy changes revealed a significant impact of ARC-3140 and of its tetrabromo equivalent ARC-1502 on the CK2alpha/CK2beta interaction. A structural inspection revealed that ARC-3140, unlike CK2beta antagonists described so far, interferes with both sub-interfaces of the bipartite CK2alpha/CK2beta interaction. Thus, ARC-3140 is a lead for the further development of highly effective compounds perturbating the quaternary structure of the CK2alpha2beta2 holoenzyme. Unexpected CK2beta-antagonistic functionality of bisubstrate inhibitors targeting protein kinase CK2.,Pietsch M, Viht K, Schnitzler A, Ekambaram R, Steinkruger M, Enkvist E, Nienberg C, Nickelsen A, Lauwers M, Jose J, Uri A, Niefind K Bioorg Chem. 2020 Jan 23;96:103608. doi: 10.1016/j.bioorg.2020.103608. PMID:32058103[5] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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