7psu
From Proteopedia
Structure of protein kinase CK2alpha mutant K198R associated with the Okur-Chung Neurodevelopmental Syndrome
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 PubMedSpecific de novo mutations in the CSNK2A1 gene, which encodes CK2alpha, the catalytic subunit of protein kinase CK2, are considered as causative for the Okur-Chung neurodevelopmental syndrome (OCNDS). OCNDS is a rare congenital disease with a high phenotypic diversity ranging from neurodevelopmental disabilities to multi-systemic problems and characteristic facial features. A frequent OCNDS mutation is the exchange of Lys198 to Arg at the center of CK2alpha's P+1 loop, a key element of substrate recognition. According to preliminary data recently made available, this mutation causes a significant shift of the substrate specificity of the enzyme. We expressed the CK2alpha(Lys198Arg) recombinantly and characterized it biophysically and structurally. Using isothermal titration calorimetry (ITC), fluorescence quenching and differential scanning fluorimetry (Thermofluor), we found that the mutation does not affect the interaction with CK2beta, the non-catalytic CK2 subunit, and that the thermal stability of the protein is even slightly increased. However, a CK2alpha(Lys198Arg) crystal structure and its comparison with wild-type structures revealed a significant shift of the anion binding site harboured by the P+1 loop. This observation supports the notion that the Lys198Arg mutation causes an alteration of substrate specificity which we underpinned here with enzymological data. Structural and Enzymological Evidence for an Altered Substrate Specificity in Okur-Chung Neurodevelopmental Syndrome Mutant CK2alpha(Lys198Arg).,Werner C, Gast A, Lindenblatt D, Nickelsen A, Niefind K, Jose J, Hochscherf J Front Mol Biosci. 2022 Apr 4;9:831693. doi: 10.3389/fmolb.2022.831693., eCollection 2022. PMID:35445078[5] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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