1
|
Dalle S. Targeting Protein Kinases to Protect Beta-Cell Function and Survival in Diabetes. Int J Mol Sci 2024; 25:6425. [PMID: 38928130 PMCID: PMC11203834 DOI: 10.3390/ijms25126425] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2024] [Revised: 05/30/2024] [Accepted: 05/31/2024] [Indexed: 06/28/2024] Open
Abstract
The prevalence of diabetes is increasing worldwide. Massive death of pancreatic beta-cells causes type 1 diabetes. Progressive loss of beta-cell function and mass characterizes type 2 diabetes. To date, none of the available antidiabetic drugs promotes the maintenance of a functional mass of endogenous beta-cells, revealing an unmet medical need. Dysfunction and apoptotic death of beta-cells occur, in particular, through the activation of intracellular protein kinases. In recent years, protein kinases have become highly studied targets of the pharmaceutical industry for drug development. A number of drugs that inhibit protein kinases have been approved for the treatment of cancers. The question of whether safe drugs that inhibit protein kinase activity can be developed and used to protect the function and survival of beta-cells in diabetes is still unresolved. This review presents arguments suggesting that several protein kinases in beta-cells may represent targets of interest for the development of drugs to treat diabetes.
Collapse
Affiliation(s)
- Stéphane Dalle
- Institut de Génomique Fonctionnelle, Université de Montpellier, Centre National de la Recherche Scientifique (CNRS), Institut National de la Santé et de la Recherche Médicale (INSERM), 34094 Montpellier, France
| |
Collapse
|
2
|
Choi Y, Yu SR, Lee Y, Na AY, Lee S, Heitman J, Seo R, Lee HS, Lee JS, Bahn YS. Casein kinase 2 complex: a central regulator of multiple pathobiological signaling pathways in Cryptococcus neoformans. mBio 2024; 15:e0327523. [PMID: 38193728 PMCID: PMC10865844 DOI: 10.1128/mbio.03275-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Accepted: 12/11/2023] [Indexed: 01/10/2024] Open
Abstract
The casein kinase 2 (CK2) complex has garnered extensive attention over the past decades as a potential therapeutic target for diverse human diseases, including cancer, diabetes, and obesity, due to its pivotal roles in eukaryotic growth, differentiation, and metabolic homeostasis. While CK2 is also considered a promising antifungal target, its role in fungal pathogens remains unexplored. In this study, we investigated the functions and regulatory mechanisms of the CK2 complex in Cryptococcus neoformans, a major cause of fungal meningitis. The cryptococcal CK2 complex consists of a single catalytic subunit, Cka1, and two regulatory subunits, Ckb1 and Ckb2. Our findings show that Cka1 plays a primary role as a protein kinase, while Ckb1 and Ckb2 have major and minor regulatory functions, respectively, in growth, cell cycle control, morphogenesis, stress response, antifungal drug resistance, and virulence factor production. Interestingly, triple mutants lacking all three subunits (cka1Δ ckb1Δ ckb2Δ) exhibited more severe phenotypic defects than the cka1Δ mutant alone, suggesting that Ckb1/2 may have Cka1-independent functions. In a murine model of systemic cryptococcosis, cka1Δ and cka1Δ ckb1Δ ckb2Δ mutants showed severely reduced virulence. Transcriptomic, proteomic, and phosphoproteomic analyses further revealed that the CK2 complex controls a wide array of effector proteins involved in transcriptional regulation, cell cycle control, nutrient metabolisms, and stress responses. Most notably, CK2 disruption led to dysregulation of key signaling cascades central to C. neoformans pathogenicity, including the Hog1, Mpk1 MAPKs, cAMP/PKA, and calcium/calcineurin signaling pathways. In summary, our study provides novel insights into the multifaceted roles of the fungal CK2 complex and presents a compelling case for targeting it in the development of new antifungal drugs.IMPORTANCEThe casein kinase 2 (CK2) complex, crucial for eukaryotic growth, differentiation, and metabolic regulation, presents a promising therapeutic target for various human diseases, including cancer, diabetes, and obesity. Its potential as an antifungal target is further highlighted in this study, which explores CK2's functions in C. neoformans, a key fungal meningitis pathogen. The CK2 complex in C. neoformans, comprising the Cka1 catalytic subunit and Ckb1/2 regulatory subunits, is integral to processes like growth, cell cycle, morphogenesis, stress response, drug resistance, and virulence. Our findings of CK2's role in regulating critical signaling pathways, including Hog1, Mpk1 MAPKs, cAMP/PKA, and calcium/calcineurin, underscore its importance in C. neoformans pathogenicity. This study provides valuable insights into the fungal CK2 complex, reinforcing its potential as a target for novel antifungal drug development and pointing out a promising direction for creating new antifungal agents.
Collapse
Affiliation(s)
- Yeseul Choi
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, South Korea
| | - Seong-Ryong Yu
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, South Korea
| | - Yujin Lee
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, South Korea
| | - Ann-Yae Na
- School of Pharmacy, Sungkyunkwan University, Suwon, South Korea
| | - Sangkyu Lee
- School of Pharmacy, Sungkyunkwan University, Suwon, South Korea
| | - Joseph Heitman
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, USA
| | - Ran Seo
- AmtixBio Co., Ltd., Hanam-si, Gyeonggi-do, South Korea
| | - Han-Seung Lee
- AmtixBio Co., Ltd., Hanam-si, Gyeonggi-do, South Korea
| | | | - Yong-Sun Bahn
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, South Korea
| |
Collapse
|
3
|
Liu Y, Xia D, Zhong L, Chen L, Zhang L, Ai M, Mei R, Pang R. Casein Kinase 2 Affects Epilepsy by Regulating Ion Channels: A Potential Mechanism. CNS & NEUROLOGICAL DISORDERS DRUG TARGETS 2024; 23:894-905. [PMID: 37350003 DOI: 10.2174/1871527322666230622124618] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Revised: 03/31/2023] [Accepted: 04/10/2023] [Indexed: 06/24/2023]
Abstract
Epilepsy, characterized by recurrent seizures and abnormal brain discharges, is the third most common chronic disorder of the Central Nervous System (CNS). Although significant progress has been made in the research on antiepileptic drugs (AEDs), approximately one-third of patients with epilepsy are refractory to these drugs. Thus, research on the pathogenesis of epilepsy is ongoing to find more effective treatments. Many pathological mechanisms are involved in epilepsy, including neuronal apoptosis, mossy fiber sprouting, neuroinflammation, and dysfunction of neuronal ion channels, leading to abnormal neuronal excitatory networks in the brain. CK2 (Casein kinase 2), which plays a critical role in modulating neuronal excitability and synaptic transmission, has been shown to be associated with epilepsy. However, there is limited research on the mechanisms involved. Recent studies have suggested that CK2 is involved in regulating the function of neuronal ion channels by directly phosphorylating them or their binding partners. Therefore, in this review, we will summarize recent research advances regarding the potential role of CK2 regulating ion channels in epilepsy, aiming to provide more evidence for future studies.
Collapse
Affiliation(s)
- Yan Liu
- Department of Neurology, the First Affiliated Hospital of Kunming Medical University, Kunming, Yunnan, 650032, China
| | - Di Xia
- Department of Neurology, the First Affiliated Hospital of Kunming Medical University, Kunming, Yunnan, 650032, China
| | - Lianmei Zhong
- Department of Neurology, the First Affiliated Hospital of Kunming Medical University, Kunming, Yunnan, 650032, China
| | - Ling Chen
- Department of Neurology, the First Affiliated Hospital of Kunming Medical University, Kunming, Yunnan, 650032, China
- Yunnan Provincial Clinical Research Center for Neurological Disease, Kunming, Yunnan, 650032, China
| | - Linming Zhang
- Department of Neurology, the First Affiliated Hospital of Kunming Medical University, Kunming, Yunnan, 650032, China
| | - Mingda Ai
- Department of Neurology, the First Affiliated Hospital of Kunming Medical University, Kunming, Yunnan, 650032, China
| | - Rong Mei
- Department of Neurology, the First People's Hospital of Yunnan Province, Kunming, Yunnan, 650034, China
| | - Ruijing Pang
- Department of Neurology, the First Affiliated Hospital of Kunming Medical University, Kunming, Yunnan, 650032, China
| |
Collapse
|
4
|
Patel S, Vyas VK, Sharma M, Ghate M. Structure-guided discovery of adenosine triphosphate-competitive casein kinase 2 inhibitors. Future Med Chem 2023; 15:987-1014. [PMID: 37307219 DOI: 10.4155/fmc-2023-0005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023] Open
Abstract
Casein kinase 2 (CK2) is a ubiquitous, highly pleiotropic serine-threonine kinase. CK2 has been identified as a potential drug target for the treatment of cancer and related disorders. Several adenosine triphosphate-competitive CK2 inhibitors have been identified and have progressed at different levels of clinical trials. This review presents details of CK2 protein, structural insights into adenosine triphosphate binding pocket, current clinical trial candidates and their analogues. Further, it includes the emerging structure-based drug design approaches, chemistry, structure-activity relationship and biological screening of potent and selective CK2 inhibitors. The authors tabulated the details of CK2 co-crystal structures because these co-crystal structures facilitated the structure-guided discovery of CK2 inhibitors. The narrow hinge pocket compared with related kinases provides useful insights into the discovery of CK2 inhibitors.
Collapse
Affiliation(s)
- Shivani Patel
- Department of Pharmaceutical Chemistry, Institute of Pharmacy, Nirma University, Ahmedabad, Gujarat, 382481, India
| | - Vivek K Vyas
- Department of Pharmaceutical Chemistry, Institute of Pharmacy, Nirma University, Ahmedabad, Gujarat, 382481, India
| | - Manmohan Sharma
- Department of Pharmaceutical Chemistry, Institute of Pharmacy, Nirma University, Ahmedabad, Gujarat, 382481, India
| | - Manjunath Ghate
- School of Pharmacy, National Forensic Science University, Gandhinagar, Gujarat, 382007, India
| |
Collapse
|
5
|
Yang Q, Dang H, Liu J, Wang X, Wang J, Lan X, Ji M, Xing M, Hou P. Hypoxia switches TET1 from being tumor-suppressive to oncogenic. Oncogene 2023; 42:1634-1648. [PMID: 37020036 PMCID: PMC10181935 DOI: 10.1038/s41388-023-02659-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 03/01/2023] [Accepted: 03/02/2023] [Indexed: 04/07/2023]
Abstract
The classical oxidizing enzymatic activity of Ten Eleven Translocation 1 (TET1) and its tumor suppressor role are well known. Here, we find that high TET1 expression is associated with poor patient survival in solid cancers often having hypoxia, which is inconsistent with its tumor suppressor role. Through a series of in vitro and in vivo studies, using thyroid cancer as a model, we demonstrate that TET1 plays a tumor suppressor function in normoxia and, surprisingly, an oncogenic function in hypoxia. Mechanistically, TET1 mediates HIF1α-p300 interaction by acting as a co-activator of HIF1α to promote CK2B transcription under hypoxia, which is independent of its enzymatic activity; CK2 activates the AKT/GSK3β signaling pathway to promote oncogenesis. Activated AKT/GSK3β signaling in turn maintains HIF1α at elevated levels by preventing its K48-linked ubiquitination and degradation, creating a feedback loop to enhance the oncogenicity of TET1 in hypoxia. Thus, this study uncovers a novel oncogenic mechanism in which TET1 promotes oncogenesis and cancer progression through a non-enzymatic interaction between TET1 and HIF1α in hypoxia, providing novel therapeutic targeting implications for cancer.
Collapse
Affiliation(s)
- Qi Yang
- Key Laboratory for Tumor Precision Medicine of Shaanxi Province, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, 710061, PR China.
- Department of Endocrinology, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, 710061, PR China.
- Department of Otorhinolaryngology-Head and Neck Surgery, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, 710061, PR China.
| | - Hui Dang
- Department of Endocrinology, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, 710061, PR China
| | - Jiaxin Liu
- Key Laboratory for Tumor Precision Medicine of Shaanxi Province, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, 710061, PR China
| | - Xingye Wang
- Key Laboratory for Tumor Precision Medicine of Shaanxi Province, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, 710061, PR China
- Department of Structural Heart Disease, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, 710061, PR China
| | - Jingyuan Wang
- Key Laboratory for Tumor Precision Medicine of Shaanxi Province, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, 710061, PR China
- Department of Clinical Laboratory, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, 710061, PR China
| | - Xinhui Lan
- Department of Endocrinology, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, 710061, PR China
| | - Meiju Ji
- Key Laboratory for Tumor Precision Medicine of Shaanxi Province, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, 710061, PR China.
- Center for Translational Medicine, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, 710061, PR China.
| | - Mingzhao Xing
- School of Medicine, Southern University of Science and Technology, Shenzhen, 518055, Guangdong, PR China.
| | - Peng Hou
- Key Laboratory for Tumor Precision Medicine of Shaanxi Province, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, 710061, PR China.
- Department of Endocrinology, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, 710061, PR China.
| |
Collapse
|
6
|
Nickelsen A, Götz C, Lenz F, Niefind K, König S, Jose J. Analyzing the interactome of human CK2β in prostate carcinoma cells reveals HSP70-1 and Rho guanin nucleotide exchange factor 12 as novel interaction partners. FASEB Bioadv 2023; 5:114-130. [PMID: 36876296 PMCID: PMC9983076 DOI: 10.1096/fba.2022-00098] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 12/19/2022] [Accepted: 01/09/2023] [Indexed: 01/13/2023] Open
Abstract
CK2β is the non-catalytic modulating part of the S/T-protein kinase CK2. However, the overall function of CK2β is poorly understood. Here, we report on the identification of 38 new interaction partners of the human CK2β from lysates of DU145 prostate cancer cells using photo-crosslinking and mass spectrometry, whereby HSP70-1 was identified with high abundance. The KD value of its interaction with CK2β was determined as 0.57 μM by microscale thermophoresis, this being the first time, to our knowledge, that a KD value of CK2β with another protein than CK2α or CK2α' was quantified. Phosphorylation studies excluded HSP70-1 as a substrate or activity modulator of CK2, suggesting a CK2 activity independent interaction of HSP70-1 with CK2β. Co-immunoprecipitation experiments in three different cancer cell lines confirmed the interaction of HSP70-1 with CK2β in vivo. A second identified CK2β interaction partner was Rho guanin nucleotide exchange factor 12, indicating an involvement of CK2β in the Rho-GTPase signal pathway, described here for the first time to our knowledge. This points to a role of CK2β in the interaction network affecting the organization of the cytoskeleton.
Collapse
Affiliation(s)
- Anna Nickelsen
- Institute of Pharmaceutical and Medicinal ChemistryUniversity of MünsterMünsterGermany
| | - Claudia Götz
- Department of Medical Biochemistry and Molecular BiologySaarland UniversityHomburgGermany
| | - Florian Lenz
- Institute of Pharmaceutical and Medicinal ChemistryUniversity of MünsterMünsterGermany
| | - Karsten Niefind
- Department of Chemistry, Institute of BiochemistryUniversity of CologneKölnGermany
| | - Simone König
- Interdisciplinary Center for Clinical Research, Core Unit Proteomics, Medical FacultyUniversity of MünsterMünsterGermany
| | - Joachim Jose
- Institute of Pharmaceutical and Medicinal ChemistryUniversity of MünsterMünsterGermany
| |
Collapse
|
7
|
Chen Y, Wang Y, Wang J, Zhou Z, Cao S, Zhang J. Strategies of Targeting CK2 in Drug Discovery: Challenges, Opportunities, and Emerging Prospects. J Med Chem 2023; 66:2257-2281. [PMID: 36745746 DOI: 10.1021/acs.jmedchem.2c01523] [Citation(s) in RCA: 18] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
CK2 (casein kinase 2) is a serine/threonine protein kinase that is ubiquitous in eukaryotic cells and plays important roles in a variety of cellular functions, including cell growth, apoptosis, circadian rhythms, DNA damage repair, transcription, and translation. CK2 is involved in cancer pathogenesis and the occurrence of many diseases. Therefore, targeting CK2 is a promising therapeutic strategy. Although many CK2-specific small-molecule inhibitors have been developed, only CX-4945 has progressed to clinical trials. In recent years, novel CK2 inhibitors have gradually become a research hotspot, which is expected to overcome the limitations of traditional inhibitors. Herein, we summarize the structure, biological functions, and disease relevance of CK2 and emphatically analyze the structure-activity relationship (SAR) and binding modes of small-molecule CK2 inhibitors. We also discuss the latest progress of novel strategies, providing insights into new drugs targeting CK2 for clinical practice.
Collapse
Affiliation(s)
- Yijia Chen
- Joint Research Institution of Altitude Health, Department of Respiratory and Critical Care Medicine, State Key Laboratory of Biotherapy and Cancer Center, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China.,College of Life Sciences, Sichuan University, Chengdu, Sichuan 610064, China
| | - Yuxi Wang
- Joint Research Institution of Altitude Health, Department of Respiratory and Critical Care Medicine, State Key Laboratory of Biotherapy and Cancer Center, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China.,Targeted Tracer Research and Development Laboratory, Institute of Respiratory Health, Frontiers Science Center for Disease-Related Molecular Network, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China.,Tianfu Jincheng Laboratory, Chengdu, Sichuan 610041, China
| | - Jiaxing Wang
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, Memphis, Tennessee 38163, United States
| | - Zhilan Zhou
- Joint Research Institution of Altitude Health, Department of Respiratory and Critical Care Medicine, State Key Laboratory of Biotherapy and Cancer Center, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China
| | - Shu Cao
- West China School of Stomatology Sichuan University, Chengdu, Sichuan 610064, China
| | - Jifa Zhang
- Joint Research Institution of Altitude Health, Department of Respiratory and Critical Care Medicine, State Key Laboratory of Biotherapy and Cancer Center, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China.,Targeted Tracer Research and Development Laboratory, Institute of Respiratory Health, Frontiers Science Center for Disease-Related Molecular Network, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China.,Tianfu Jincheng Laboratory, Chengdu, Sichuan 610041, China
| |
Collapse
|
8
|
Unni P, Friend J, Weinberg J, Okur V, Hochscherf J, Dominguez I. Predictive functional, statistical and structural analysis of CSNK2A1 and CSNK2B variants linked to neurodevelopmental diseases. Front Mol Biosci 2022; 9:851547. [PMID: 36310603 PMCID: PMC9608649 DOI: 10.3389/fmolb.2022.851547] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Accepted: 06/29/2022] [Indexed: 12/02/2022] Open
Abstract
Okur-Chung Neurodevelopmental Syndrome (OCNDS) and Poirier-Bienvenu Neurodevelopmental Syndrome (POBINDS) were recently identified as rare neurodevelopmental disorders. OCNDS and POBINDS are associated with heterozygous mutations in the CSNK2A1 and CSNK2B genes which encode CK2α, a serine/threonine protein kinase, and CK2β, a regulatory protein, respectively, which together can form a tetrameric enzyme called protein kinase CK2. A challenge in OCNDS and POBINDS is to understand the genetic basis of these diseases and the effect of the various CK2⍺ and CK2β mutations. In this study we have collected all variants available to date in CSNK2A1 and CSNK2B, and identified hotspots. We have investigated CK2⍺ and CK2β missense mutations through prediction programs which consider the evolutionary conservation, functionality and structure or these two proteins, compared these results with published experimental data on CK2α and CK2β mutants, and suggested prediction programs that could help predict changes in functionality of CK2α mutants. We also investigated the potential effect of CK2α and CK2β mutations on the 3D structure of the proteins and in their binding to each other. These results indicate that there are functional and structural consequences of mutation of CK2α and CK2β, and provide a rationale for further study of OCNDS and POBINDS-associated mutations. These data contribute to understanding the genetic and functional basis of these diseases, which is needed to identify their underlying mechanisms.
Collapse
Affiliation(s)
- Prasida Unni
- Department of Medicine, Boston University School of Medicine and Boston Medical Center, Boston University, Boston, MA, United States
| | - Jack Friend
- Department of Medicine, Boston University School of Medicine and Boston Medical Center, Boston University, Boston, MA, United States
| | - Janice Weinberg
- Department of Biostatistics, Boston University School of Public Health, Boston University, Boston, MA, United States
| | - Volkan Okur
- New York Genome Center, New York, NY, United States
| | - Jennifer Hochscherf
- Department of Chemistry, Institute of Biochemistry, University of Cologne, Cologne, Germany
| | - Isabel Dominguez
- Department of Medicine, Boston University School of Medicine and Boston Medical Center, Boston University, Boston, MA, United States
- *Correspondence: Isabel Dominguez,
| |
Collapse
|
9
|
Ikeda A, Tsuyuguchi M, Kitagawa D, Sawa M, Nakamura S, Nakanishi I, Kinoshita T. Bivalent binding mode of an amino-pyrazole inhibitor indicates the potentials for CK2α1-selective inhibitors. Biochem Biophys Res Commun 2022; 630:30-35. [PMID: 36130444 DOI: 10.1016/j.bbrc.2022.09.040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Accepted: 09/09/2022] [Indexed: 11/02/2022]
Abstract
Casein kinase 2 (CK2) is a vital protein kinase that consists of two catalytic subunits (CK2α1 and/or CK2α2) and two regulatory subunits (CK2β). CK2α1 is a drug target for nephritis and cancers, while CK2α2 is a serious off-target because its inhibition causes testicular toxicity. High similarity between the isozymes CK2α1 and CK2α2 make it difficult to design CK2α1-specific inhibitors. Herein, the crystal structures of CK2α1 and CK2α2 complexed with a 3-amino-pyrazole inhibitor revealed the remarkable differences in the protein-inhibitor interaction modes. This inhibitor bound to the ATP binding sites of both isozymes in apparently distinct orientations. In addition, another molecule of this inhibitor bound to CK2α1, but not to CK2α2, at the CK2β protein-protein interface. Binding energy calculations and biochemical experiments suggested that this inhibitor possesses the conventional ATP-competitive characteristics with moderate allosteric function in a molecular glue mechanism. These results will assist the potential design of potent and selective CK2α1 inhibitors.
Collapse
Affiliation(s)
- Asaka Ikeda
- Graduate School of Science, Osaka Metropolitan University, Sakai, 599-8531, Japan
| | - Masato Tsuyuguchi
- Graduate School of Science, Osaka Metropolitan University, Sakai, 599-8531, Japan
| | | | | | - Shinya Nakamura
- Department of Pharmaceutical Sciences, Kindai University, Higashi-Osaka, 577-8502, Japan
| | - Isao Nakanishi
- Department of Pharmaceutical Sciences, Kindai University, Higashi-Osaka, 577-8502, Japan
| | - Takayoshi Kinoshita
- Graduate School of Science, Osaka Metropolitan University, Sakai, 599-8531, Japan.
| |
Collapse
|
10
|
Rojas DA, Urbina F, Solari A, Maldonado E. The Catalytic Subunit of Schizosaccharomyces pombe CK2 (Cka1) Negatively Regulates RNA Polymerase II Transcription through Phosphorylation of Positive Cofactor 4 (PC4). Int J Mol Sci 2022; 23:ijms23169499. [PMID: 36012759 PMCID: PMC9409219 DOI: 10.3390/ijms23169499] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 08/16/2022] [Accepted: 08/17/2022] [Indexed: 01/04/2023] Open
Abstract
Positive cofactor 4 (PC4) is a transcriptional coactivator that plays important roles in transcription and DNA replication. In mammals, PC4 is phosphorylated by CK2, and this event downregulates its RNA polymerase II (RNAPII) coactivator function. This work describes the effect of fission yeast PC4 phosphorylation on RNAPII transcription in a cell extract, which closely resembles the cellular context. We found that fission yeast PC4 is strongly phosphorylated by the catalytic subunit of CK2 (Cka1), while the regulatory subunit (Ckb1) downregulates the PC4 phosphorylation. The addition of Cka1 to an in vitro transcription assay can diminish the basal transcription from the Ad-MLP promoter; however, the addition of recombinant fission yeast PC4 or Ckb1 can stimulate the basal transcription in a cell extract. Fission yeast PC4 is phosphorylated in a domain which has consensus phosphorylation sites for CK2, and two serine residues were identified as critical for CK2 phosphorylation. Mutation of one of the serine residues in PC4 does not completely abolish the phosphorylation; however, when the two serine residues are mutated, CK2 is no longer able to phosphorylate PC4. The mutant which is not phosphorylated is able to stimulate transcription even though it is previously phosphorylated by Cka1, while the wild type and the point mutant are inactivated by Cka1 phosphorylation, and they cannot stimulate transcription by RNAPII in cell extracts. Those results demonstrate that CK2 can regulate the coactivator function of fission yeast PC4 and suggests that this event could be important in vivo as well.
Collapse
Affiliation(s)
- Diego A. Rojas
- Instituto de Ciencias Biomédicas (ICB), Facultad de Ciencias de la Salud, Universidad Autónoma de Chile, Santiago 8910132, Chile
- Correspondence: (D.A.R.); (E.M.)
| | - Fabiola Urbina
- Programa de Biología Celular y Molecular, Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Santiago 8380492, Chile
| | - Aldo Solari
- Programa de Biología Celular y Molecular, Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Santiago 8380492, Chile
| | - Edio Maldonado
- Programa de Biología Celular y Molecular, Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Santiago 8380492, Chile
- Correspondence: (D.A.R.); (E.M.)
| |
Collapse
|
11
|
Asif M, Kaygusuz E, Shinawi M, Nickelsen A, Hsieh TC, Wagle P, Budde BS, Hochscherf J, Abdullah U, Höning S, Nienberg C, Lindenblatt D, Noegel AA, Altmüller J, Thiele H, Motameny S, Fleischer N, Segal I, Pais L, Tinschert S, Samra NN, Savatt JM, Rudy NL, De Luca C, Paola Fortugno, White SM, Krawitz P, Hurst ACE, Niefind K, Jose J, Brancati F, Nürnberg P, Hussain MS. De novo variants of CSNK2B cause a new intellectual disability-craniodigital syndrome by disrupting the canonical Wnt signaling pathway. HGG ADVANCES 2022; 3:100111. [PMID: 35571680 PMCID: PMC9092267 DOI: 10.1016/j.xhgg.2022.100111] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Accepted: 04/13/2022] [Indexed: 11/29/2022] Open
Abstract
CSNK2B encodes for casein kinase II subunit beta (CK2β), the regulatory subunit of casein kinase II (CK2), which is known to mediate diverse cellular pathways. Variants in this gene have been recently identified as a cause of Poirier-Bienvenu neurodevelopmental syndrome (POBINDS), but functional evidence is sparse. Here, we report five unrelated individuals: two of them manifesting POBINDS, while three are identified to segregate a new intellectual disability-craniodigital syndrome (IDCS), distinct from POBINDS. The three IDCS individuals carried two different de novo missense variants affecting the same codon of CSNK2B. Both variants, NP_001311.3; p.Asp32His and NP_001311.3; p.Asp32Asn, lead to an upregulation of CSNK2B expression at transcript and protein level, along with global dysregulation of canonical Wnt signaling. We found impaired interaction of the two key players DVL3 and β-catenin with mutated CK2β. The variants compromise the kinase activity of CK2 as evident by a marked reduction of phosphorylated β-catenin and consequent absence of active β-catenin inside nuclei of the patient-derived lymphoblastoid cell lines (LCLs). In line with these findings, whole-transcriptome profiling of patient-derived LCLs harboring the NP_001311.3; p.Asp32His variant confirmed a marked difference in expression of genes involved in the Wnt signaling pathway. In addition, whole-phosphoproteome analysis of the LCLs of the same subject showed absence of phosphorylation for 313 putative CK2 substrates, enriched in the regulation of nuclear β-catenin and transcription of the target genes. Our findings suggest that discrete variants in CSNK2B cause dominant-negative perturbation of the canonical Wnt signaling pathway, leading to a new craniodigital syndrome distinguishable from POBINDS.
Collapse
Affiliation(s)
- Maria Asif
- Cologne Center for Genomics (CCG), University of Cologne, Faculty of Medicine and University Hospital Cologne, 50931 Cologne, Germany.,Center for Biochemistry, Medical Faculty, University of Cologne, 50931 Cologne, Germany.,Center for Molecular Medicine Cologne (CMMC), University of Cologne, Faculty of Medicine and University Hospital Cologne, 50931 Cologne, Germany
| | - Emrah Kaygusuz
- Center for Biochemistry, Medical Faculty, University of Cologne, 50931 Cologne, Germany.,Bilecik Şeyh Edebali University, Molecular Biology and Genetics, Gülümbe Campus, 11230 Bilecik, Turkey
| | - Marwan Shinawi
- Division of Genetics and Genomic Medicine, Department of Pediatrics, Washington University School of Medicine, St. Louis, MO, USA
| | - Anna Nickelsen
- Institute of Pharmaceutical and Medicinal Chemistry, Westphalian Wilhelms-University, Münster, Germany
| | - Tzung-Chien Hsieh
- Institute for Genomic Statistics and Bioinformatics, University Hospital Bonn, Rheinische Friedrich Wilhelms, Universität Bonn, Bonn, Germany
| | - Prerana Wagle
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Birgit S Budde
- Cologne Center for Genomics (CCG), University of Cologne, Faculty of Medicine and University Hospital Cologne, 50931 Cologne, Germany
| | - Jennifer Hochscherf
- Department of Chemistry, Institute of Biochemistry, University of Cologne, Cologne, Germany
| | - Uzma Abdullah
- University Institute of Biochemistry and Biotechnology (UIBB), PMAS-Arid Agriculture University, Rawalpindi, Pakistan
| | - Stefan Höning
- Center for Biochemistry, Medical Faculty, University of Cologne, 50931 Cologne, Germany
| | - Christian Nienberg
- Institute of Pharmaceutical and Medicinal Chemistry, Westphalian Wilhelms-University, Münster, Germany
| | - Dirk Lindenblatt
- Department of Chemistry, Institute of Biochemistry, University of Cologne, Cologne, Germany
| | - Angelika A Noegel
- Center for Biochemistry, Medical Faculty, University of Cologne, 50931 Cologne, Germany.,Center for Molecular Medicine Cologne (CMMC), University of Cologne, Faculty of Medicine and University Hospital Cologne, 50931 Cologne, Germany
| | - Janine Altmüller
- Cologne Center for Genomics (CCG), University of Cologne, Faculty of Medicine and University Hospital Cologne, 50931 Cologne, Germany.,Berlin Institute of Health at Charité - Universitätsmedizin Berlin, Core Facility Genomics, Charitéplatz 1, 10117 Berlin, Germany.,Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany
| | - Holger Thiele
- Cologne Center for Genomics (CCG), University of Cologne, Faculty of Medicine and University Hospital Cologne, 50931 Cologne, Germany
| | - Susanne Motameny
- Cologne Center for Genomics (CCG), University of Cologne, Faculty of Medicine and University Hospital Cologne, 50931 Cologne, Germany
| | | | | | - Lynn Pais
- Center for Mendelian Genomics, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Sigrid Tinschert
- Zentrum Medizinische Genetik, Medizinische Universität, Innsbruck, Austria
| | - Nadra Nasser Samra
- Hospital Center, Safed, Israel.,Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
| | | | - Natasha L Rudy
- Department of Genetics, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Chiara De Luca
- Department of Life, Health and Environmental Science, University of L'Aquila, 67100 L'Aquila, Italy
| | | | - Paola Fortugno
- Department of Life, Health and Environmental Science, University of L'Aquila, 67100 L'Aquila, Italy.,IRCCS, San Raffaele Roma, 00163 Roma, Italy
| | - Susan M White
- Victorian Clinical Genetics Services, Murdoch Children's Research Institute, Melbourne, VIC, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, VIC, Australia
| | - Peter Krawitz
- Institute for Genomic Statistics and Bioinformatics, University Hospital Bonn, Rheinische Friedrich Wilhelms, Universität Bonn, Bonn, Germany
| | - Anna C E Hurst
- Department of Genetics, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Karsten Niefind
- Department of Chemistry, Institute of Biochemistry, University of Cologne, Cologne, Germany
| | - Joachim Jose
- Institute of Pharmaceutical and Medicinal Chemistry, Westphalian Wilhelms-University, Münster, Germany
| | - Francesco Brancati
- Department of Life, Health and Environmental Science, University of L'Aquila, 67100 L'Aquila, Italy.,IRCCS, San Raffaele Roma, 00163 Roma, Italy
| | - Peter Nürnberg
- Cologne Center for Genomics (CCG), University of Cologne, Faculty of Medicine and University Hospital Cologne, 50931 Cologne, Germany.,Center for Molecular Medicine Cologne (CMMC), University of Cologne, Faculty of Medicine and University Hospital Cologne, 50931 Cologne, Germany
| | - Muhammad Sajid Hussain
- Cologne Center for Genomics (CCG), University of Cologne, Faculty of Medicine and University Hospital Cologne, 50931 Cologne, Germany.,Center for Biochemistry, Medical Faculty, University of Cologne, 50931 Cologne, Germany.,Center for Molecular Medicine Cologne (CMMC), University of Cologne, Faculty of Medicine and University Hospital Cologne, 50931 Cologne, Germany
| |
Collapse
|
12
|
Werner C, Gast A, Lindenblatt D, Nickelsen A, Niefind K, Jose J, Hochscherf J. Structural and Enzymological Evidence for an Altered Substrate Specificity in Okur-Chung Neurodevelopmental Syndrome Mutant CK2αLys198Arg. Front Mol Biosci 2022; 9:831693. [PMID: 35445078 PMCID: PMC9014129 DOI: 10.3389/fmolb.2022.831693] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Accepted: 02/28/2022] [Indexed: 11/13/2022] Open
Abstract
Specific de novo mutations in the CSNK2A1 gene, which encodes CK2α, 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 CK2α′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 CK2αLys198Arg 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 CK2β, the non-catalytic CK2 subunit, and that the thermal stability of the protein is even slightly increased. However, a CK2αLys198Arg 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.
Collapse
Affiliation(s)
- Christian Werner
- Department of Chemistry, Institute of Biochemistry, University of Cologne, Cologne, Germany
| | - Alexander Gast
- Institute of Pharmaceutical and Medicinal Chemistry, University of Münster, Münster, Germany
| | - Dirk Lindenblatt
- Department of Chemistry, Institute of Biochemistry, University of Cologne, Cologne, Germany
| | - Anna Nickelsen
- Institute of Pharmaceutical and Medicinal Chemistry, University of Münster, Münster, Germany
| | - Karsten Niefind
- Department of Chemistry, Institute of Biochemistry, University of Cologne, Cologne, Germany
| | - Joachim Jose
- Institute of Pharmaceutical and Medicinal Chemistry, University of Münster, Münster, Germany
| | - Jennifer Hochscherf
- Department of Chemistry, Institute of Biochemistry, University of Cologne, Cologne, Germany
- *Correspondence: Jennifer Hochscherf,
| |
Collapse
|
13
|
Wilke MVMB, Oliveira BM, Pereira A, Doriqui MJR, Kok F, Souza CFM. Two different presentations of de novo variants of CSNK2B: two case reports. J Med Case Rep 2022; 16:4. [PMID: 34983633 PMCID: PMC8728954 DOI: 10.1186/s13256-021-03184-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Accepted: 11/08/2021] [Indexed: 11/10/2022] Open
Abstract
Background Poirier–Bienvenu neurodevelopmental syndrome is a neurologic disorder caused by mutations in the CSNK2B gene. It is mostly characterized by early-onset seizures, hypotonia, and mild dysmorphic features. Craniodigital syndrome is a recently described disorder also related to CSNK2B, with a single report in the literature. Objective To report two unrelated cases of children harboring CSNK2B variants (NM_001320.6) who presented with distinct diseases. Case report Case 1 is a 7-month-old, Caucasian, female patient with chief complaints of severe hypotonia and drug-refractory myoclonic epilepsy, with a likely pathogenic de novo variant c.494A>G (p.His165Arg). Case 2 is a 5-year-old male, Latino patient with craniodigital intellectual disability syndrome subjacent to a de novo, likely pathogenic variant c.94G>T (p.Asp32Tyr). His dysmorphic features included facial dysmorphisms, supernumerary nipples, and left-hand postaxial polydactyly. Conclusion This report suggest that the CSNK2B gene may be involved in the physiopathology of neurodevelopmental disorders and variable dysmorphic features.
Collapse
Affiliation(s)
- Matheus V M B Wilke
- Medical Genetics Service, Hospital de Clínicas de Porto Alegre, Rua Ramiro Barcelos, 2350 - 3º andar, Porto Alegre, RS, 90035-007, Brazil.,Post Graduate Program in Medical Sciences, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Bibiana M Oliveira
- Medical Genetics Service, Hospital de Clínicas de Porto Alegre, Rua Ramiro Barcelos, 2350 - 3º andar, Porto Alegre, RS, 90035-007, Brazil.,Post Graduate Program in Genetics and Molecular Biology, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.,Mendelics Genomic Analysis, São Paulo, SP, Brazil
| | - Alessandra Pereira
- Pediatrics Service, Neuropediatrics, Hospital Moinhos de Vento, Porto Alegre, RS, Brazil
| | | | - Fernando Kok
- Mendelics Genomic Analysis, São Paulo, SP, Brazil
| | - Carolina F M Souza
- Medical Genetics Service, Hospital de Clínicas de Porto Alegre, Rua Ramiro Barcelos, 2350 - 3º andar, Porto Alegre, RS, 90035-007, Brazil.
| |
Collapse
|
14
|
Iegre J, Atkinson EL, Brear PD, Cooper BM, Hyvönen M, Spring DR. Chemical probes targeting the kinase CK2: a journey outside the catalytic box. Org Biomol Chem 2021; 19:4380-4396. [PMID: 34037044 DOI: 10.1039/d1ob00257k] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
CK2 is a protein kinase that plays important roles in many physio-pathological cellular processes. As such, the development of chemical probes for CK2 has received increasing attention in the past decade with more than 40 lead compounds developed. In this review, we aim to provide the reader with a comprehensive overview of the chemical probes acting outside the highly-conserved ATP-site developed to date. Such probes belong to different classes of molecules spanning from small molecules to peptides, act with a range of mechanisms of action and some of them present themselves as promising tools to investigate the biology of CK2 and therefore develop therapeutics for many disease areas including cancer and COVID-19.
Collapse
Affiliation(s)
- Jessica Iegre
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK.
| | - Eleanor L Atkinson
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK.
| | - Paul D Brear
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge, CB2 1GA, UK
| | - Bethany M Cooper
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK.
| | - Marko Hyvönen
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge, CB2 1GA, UK
| | - David R Spring
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK.
| |
Collapse
|
15
|
Montenarh M, Götz C. Protein kinase CK2 and ion channels (Review). Biomed Rep 2020; 13:55. [PMID: 33082952 PMCID: PMC7560519 DOI: 10.3892/br.2020.1362] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Accepted: 07/28/2020] [Indexed: 12/18/2022] Open
Abstract
Protein kinase CK2 appears as a tetramer or higher molecular weight oligomer composed of catalytic CK2α, CK2α' subunits and non-catalytic regulatory CK2β subunits or as individual subunits. It is implicated in a variety of different regulatory processes, such as Akt signalling, splicing and DNA repair within eukaryotic cells. The present review evaluates the influence of CK2 on ion channels in the plasma membrane. CK2 phosphorylates platform proteins such as calmodulin and ankyrin G, which bind to channel proteins for a physiological transport to and positioning into the membrane. In addition, CK2 directly phosphorylates a variety of channel proteins directly to regulate opening and closing of the channels. Thus, modulation of CK2 activities by specific inhibitors, by siRNA technology or by CRISPR/Cas technology has an influence on intracellular ion concentrations and thereby on cellular signalling. The physiological regulation of the intracellular ion concentration is important for cell survival and correct intracellular signalling. Disturbance of this regulation results in a variety of different diseases including epilepsy, heart failure, cystic fibrosis and diabetes. Therefore, these effects should be considered when using CK2 inhibition as a treatment option for cancer.
Collapse
Affiliation(s)
- Mathias Montenarh
- Medical Biochemistry and Molecular Biology, Saarland University, D-66424 Homburg, Saarland, Germany
| | - Claudia Götz
- Medical Biochemistry and Molecular Biology, Saarland University, D-66424 Homburg, Saarland, Germany
| |
Collapse
|
16
|
Kröger L, Daniliuc CG, Ensan D, Borgert S, Nienberg C, Lauwers M, Steinkrüger M, Jose J, Pietsch M, Wünsch B. Synthesis and SAR of Tetracyclic Inhibitors of Protein Kinase CK2 Derived from Furocarbazole W16. ChemMedChem 2020; 15:871-881. [PMID: 32168422 PMCID: PMC7418559 DOI: 10.1002/cmdc.202000040] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Revised: 03/06/2020] [Indexed: 12/16/2022]
Abstract
The serine/threonine kinase CK2 modulates the activity of more than 300 proteins and thus plays a crucial role in various physiological and pathophysiological processes including neurodegenerative disorders of the central nervous system and cancer. The enzymatic activity of CK2 is controlled by the equilibrium between the heterotetrameric holoenzyme CK2α2β2 and its monomeric subunits CK2α and CK2β. A series of analogues of W16 ((3aR,4S,10S,10aS)‐4‐{[(S)‐4‐benzyl‐2‐oxo‐1,3‐oxazolidin‐3‐yl]carbonyl}‐10‐(3,4,5‐trimethoxyphenyl)‐4,5,10,10a‐tetrahydrofuro[3,4‐b]carbazole‐1,3(3aH)‐dione ((+)‐3
a)) was prepared in an one‐pot, three‐component Levy reaction. The stereochemistry of the tetracyclic compounds was analyzed. Additionally, the chemically labile anhydride structure of the furocarbazoles 3 was replaced by a more stable imide (9) and N‐methylimide (10) substructure. The enantiomer (−)‐3
a (Ki=4.9 μM) of the lead compound (+)‐3
a (Ki=31 μM) showed a more than sixfold increased inhibition of the CK2α/CK2β interaction (protein‐protein interaction inhibition, PPII) in a microscale thermophoresis (MST) assay. However, (−)‐3
a did not show an increased enzyme inhibition of the CK2α2β2 holoenzyme, the CK2α subunit or the mutated CK2α′ C336S subunit in the capillary electrophoresis assay. In the pyrrolocarbazole series, the imide (−)‐9
a (Ki=3.6 μM) and the N‐methylimide (+)‐10
a (Ki=2.8 μM) represent the most promising inhibitors of the CK2α/CK2β interaction. However, neither compound could inhibit enzymatic activity. Unexpectedly, the racemic tetracyclic pyrrolocarbazole (±)‐12, with a carboxy moiety in the 4‐position, displays the highest CK2α/CK2β interaction inhibition (Ki=1.8 μM) of this series of compounds.
Collapse
Affiliation(s)
- Lukas Kröger
- Institut für Pharmazeutische und Medizinische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstraße 48, 8149, Münster, Germany
| | - Constantin G Daniliuc
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstraße 40, 48149, Münster, Germany
| | - Deeba Ensan
- Institut für Pharmazeutische und Medizinische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstraße 48, 8149, Münster, Germany
| | - Sebastian Borgert
- Institut für Pharmazeutische und Medizinische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstraße 48, 8149, Münster, Germany
| | - Christian Nienberg
- Institut für Pharmazeutische und Medizinische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstraße 48, 8149, Münster, Germany
| | - Miriam Lauwers
- Medizinische Fakultät, Universität Köln, Gleueler Straße 24, 50931, Köln, Germany
| | - Michaela Steinkrüger
- Medizinische Fakultät, Universität Köln, Gleueler Straße 24, 50931, Köln, Germany
| | - Joachim Jose
- Institut für Pharmazeutische und Medizinische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstraße 48, 8149, Münster, Germany
| | - Markus Pietsch
- Medizinische Fakultät, Universität Köln, Gleueler Straße 24, 50931, Köln, Germany
| | - Bernhard Wünsch
- Institut für Pharmazeutische und Medizinische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstraße 48, 8149, Münster, Germany.,Cells-in-Motion Cluster of Excellence (EXC 1003-CiM), Westfälische Wilhelms-Universität Münster, Waldeyerstraße 15, 48149, Münster, Germany
| |
Collapse
|
17
|
Pietsch M, Viht K, Schnitzler A, Ekambaram R, Steinkrüger M, Enkvist E, Nienberg C, Nickelsen A, Lauwers M, Jose J, Uri A, Niefind K. Unexpected CK2β-antagonistic functionality of bisubstrate inhibitors targeting protein kinase CK2. Bioorg Chem 2020; 96:103608. [PMID: 32058103 DOI: 10.1016/j.bioorg.2020.103608] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 12/11/2019] [Accepted: 01/20/2020] [Indexed: 01/17/2023]
Abstract
Protein kinase CK2, a heterotetrameric holoenzyme composed of two catalytic chains (CK2α) attached to a homodimer of regulatory subunits (CK2β), 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 CK2α, three copies of the inhibitor are visible, one of them at the CK2β interface of CK2α. 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 CK2α/CK2β interaction. A structural inspection revealed that ARC-3140, unlike CK2β antagonists described so far, interferes with both sub-interfaces of the bipartite CK2α/CK2β interaction. Thus, ARC-3140 is a lead for the further development of highly effective compounds perturbating the quaternary structure of the CK2α2β2 holoenzyme.
Collapse
Affiliation(s)
- Markus Pietsch
- Institut II für Pharmakologie, Zentrum für Pharmakologie, Medizinische Fakultät, Universität zu Köln, Gleueler Str. 24, D-50931 Köln, Germany
| | - Kaido Viht
- Institute of Chemistry, University of Tartu, 14A Ravila St., 50411 Tartu, Estonia
| | - Alexander Schnitzler
- Institut für Biochemie, Department für Chemie, Universität zu Köln, Zülpicher Str. 47, D-50674 Köln, Germany
| | - Ramesh Ekambaram
- Institute of Chemistry, University of Tartu, 14A Ravila St., 50411 Tartu, Estonia
| | - Michaela Steinkrüger
- Institut II für Pharmakologie, Zentrum für Pharmakologie, Medizinische Fakultät, Universität zu Köln, Gleueler Str. 24, D-50931 Köln, Germany
| | - Erki Enkvist
- Institute of Chemistry, University of Tartu, 14A Ravila St., 50411 Tartu, Estonia
| | - Christian Nienberg
- Institut für Pharmazeutische und Medizinische Chemie, Westfälische Wilhelms-Universität Münster, PharmaCampus, Corrensstr. 48, D-48149 Münster, Germany
| | - Anna Nickelsen
- Institut für Pharmazeutische und Medizinische Chemie, Westfälische Wilhelms-Universität Münster, PharmaCampus, Corrensstr. 48, D-48149 Münster, Germany
| | - Miriam Lauwers
- Institut II für Pharmakologie, Zentrum für Pharmakologie, Medizinische Fakultät, Universität zu Köln, Gleueler Str. 24, D-50931 Köln, Germany
| | - Joachim Jose
- Institut für Pharmazeutische und Medizinische Chemie, Westfälische Wilhelms-Universität Münster, PharmaCampus, Corrensstr. 48, D-48149 Münster, Germany
| | - Asko Uri
- Institute of Chemistry, University of Tartu, 14A Ravila St., 50411 Tartu, Estonia.
| | - Karsten Niefind
- Institut für Biochemie, Department für Chemie, Universität zu Köln, Zülpicher Str. 47, D-50674 Köln, Germany.
| |
Collapse
|
18
|
Kufareva I, Bestgen B, Brear P, Prudent R, Laudet B, Moucadel V, Ettaoussi M, Sautel CF, Krimm I, Engel M, Filhol O, Borgne ML, Lomberget T, Cochet C, Abagyan R. Discovery of holoenzyme-disrupting chemicals as substrate-selective CK2 inhibitors. Sci Rep 2019; 9:15893. [PMID: 31685885 PMCID: PMC6828666 DOI: 10.1038/s41598-019-52141-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 10/07/2019] [Indexed: 01/06/2023] Open
Abstract
CK2 is a constitutively active protein kinase overexpressed in numerous malignancies. Interaction between CK2α and CK2β subunits is essential for substrate selectivity. The CK2α/CK2β interface has been previously targeted by peptides to achieve functional effects; however, no small molecules modulators were identified due to pocket flexibility and open shape. Here we generated numerous plausible conformations of the interface using the fumigation modeling protocol, and virtually screened a compound library to discover compound 1 that suppressed CK2α/CK2β interaction in vitro and inhibited CK2 in a substrate-selective manner. Orthogonal SPR, crystallography, and NMR experiments demonstrated that 4 and 6, improved analogs of 1, bind to CK2α as predicted. Both inhibitors alter CK2 activity in cells through inhibition of CK2 holoenzyme formation. Treatment with 6 suppressed MDA-MB231 triple negative breast cancer cell growth and induced apoptosis. Altogether, our findings exemplify an innovative computational-experimental approach and identify novel non-peptidic inhibitors of CK2 subunit interface disclosing substrate-selective functional effects.
Collapse
Affiliation(s)
- Irina Kufareva
- University of California, San Diego, Skaggs School of Pharmacy and Pharmaceutical Sciences, La Jolla, CA, 92093, USA
| | - Benoit Bestgen
- Université de Lyon, Université Claude Bernard Lyon 1, Faculté de Pharmacie - ISPB, EA 4446 Bioactive Molecules and Medicinal Chemistry, 8 avenue Rockefeller, F-69373, Lyon, cedex 8, France.,Pharmaceutical and Medicinal Chemistry, Saarland University, Campus C2.3, D-66123, Saarbrücken, Germany.,Univ. Grenoble Alpes, Inserm U1036, CEA, BCI Laboratory, IRIG, F-38000, Grenoble, France.,Ecrins Therapeutics, 5 Avenue du Grand Sablon, 38700, La Tronche, France
| | - Paul Brear
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge, CB2 1GA, UK
| | - Renaud Prudent
- Univ. Grenoble Alpes, Inserm U1036, CEA, BCI Laboratory, IRIG, F-38000, Grenoble, France.,Cellipse MINATEC, 7 Parvis Louis Néel, 38000, Grenoble, cedex 9, France
| | - Béatrice Laudet
- Univ. Grenoble Alpes, Inserm U1036, CEA, BCI Laboratory, IRIG, F-38000, Grenoble, France.,CHU Toulouse, Emergency Department, F-31000, Toulouse, France
| | - Virginie Moucadel
- Univ. Grenoble Alpes, Inserm U1036, CEA, BCI Laboratory, IRIG, F-38000, Grenoble, France.,BioMérieux SA, Centre Christophe Mérieux, 5 rue des Berges, 38024, Grenoble, cedex 1, France
| | - Mohamed Ettaoussi
- Université de Lyon, Université Claude Bernard Lyon 1, Faculté de Pharmacie - ISPB, EA 4446 Bioactive Molecules and Medicinal Chemistry, 8 avenue Rockefeller, F-69373, Lyon, cedex 8, France
| | - Celine F Sautel
- Univ. Grenoble Alpes, Inserm U1036, CEA, BCI Laboratory, IRIG, F-38000, Grenoble, France.,DERMADIS, 218 avenue Marie Curie, 74160, Archamps, France
| | - Isabelle Krimm
- Centre de RMN à Très Hauts Champs, Université de Lyon, CNRS, Université Claude Bernard Lyon 1, ENS, 5 rue de la Doua, F-69100, Villeurbanne, France
| | - Matthias Engel
- Pharmaceutical and Medicinal Chemistry, Saarland University, Campus C2.3, D-66123, Saarbrücken, Germany
| | - Odile Filhol
- Univ. Grenoble Alpes, Inserm U1036, CEA, BCI Laboratory, IRIG, F-38000, Grenoble, France
| | - Marc Le Borgne
- Université de Lyon, Université Claude Bernard Lyon 1, Faculté de Pharmacie - ISPB, EA 4446 Bioactive Molecules and Medicinal Chemistry, 8 avenue Rockefeller, F-69373, Lyon, cedex 8, France
| | - Thierry Lomberget
- Université de Lyon, Université Claude Bernard Lyon 1, Faculté de Pharmacie - ISPB, EA 4446 Bioactive Molecules and Medicinal Chemistry, 8 avenue Rockefeller, F-69373, Lyon, cedex 8, France
| | - Claude Cochet
- Univ. Grenoble Alpes, Inserm U1036, CEA, BCI Laboratory, IRIG, F-38000, Grenoble, France.
| | - Ruben Abagyan
- University of California, San Diego, Skaggs School of Pharmacy and Pharmaceutical Sciences, La Jolla, CA, 92093, USA.
| |
Collapse
|
19
|
Protein kinase CK2 is involved in zinc homeostasis in breast and prostate cancer cells. Biometals 2019; 32:861-873. [DOI: 10.1007/s10534-019-00218-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Accepted: 09/28/2019] [Indexed: 01/27/2023]
|
20
|
Protein Kinase CK2-A Putative Target for the Therapy of Diabetes Mellitus? Int J Mol Sci 2019; 20:ijms20184398. [PMID: 31500224 PMCID: PMC6770776 DOI: 10.3390/ijms20184398] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Revised: 09/04/2019] [Accepted: 09/05/2019] [Indexed: 02/06/2023] Open
Abstract
Since diabetes is a global epidemic, the development of novel therapeutic strategies for the treatment of this disease is of major clinical interest. Diabetes is differentiated in two types: type 1 diabetes mellitus (T1DM) and type 2 diabetes mellitus (T2DM). T1DM arises from an autoimmune destruction of insulin-producing β-cells whereas T2DM is characterized by an insulin resistance, an impaired insulin reaction of the target cells, and/or dysregulated insulin secretion. In the past, a growing number of studies have reported on the important role of the protein kinase CK2 in the regulation of the survival and endocrine function of pancreatic β-cells. In fact, inhibition of CK2 is capable of reducing cytokine-induced loss of β-cells and increases insulin expression as well as secretion by various pathways that are regulated by reversible phosphorylation of proteins. Moreover, CK2 inhibition modulates pathways that are involved in the development of diabetes and prevents signal transduction, leading to late complications such as diabetic retinopathy. Hence, targeting CK2 may represent a novel therapeutic strategy for the treatment of diabetes.
Collapse
|
21
|
Lindenblatt D, Horn M, Götz C, Niefind K, Neundorf I, Pietsch M. Design of CK2β-Mimicking Peptides as Tools To Study the CK2α/CK2β Interaction in Cancer Cells. ChemMedChem 2019; 14:833-841. [PMID: 30786177 DOI: 10.1002/cmdc.201800786] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Indexed: 11/07/2022]
Abstract
The ubiquitously expressed Ser/Thr kinase CK2 is a key regulator in a variety of key processes in normal and malignant cells. Due to its distinctive anti-apoptotic and tumor-driving properties, elevated levels of CK2 have frequently been found in tumors of different origin. In recent years, development of CK2 inhibitors has largely been focused on ATP-competitive compounds; however, targeting the CK2α/CK2β interface has emerged as a further concept that might avoid selectivity issues. To address the CK2 subunit interaction site, we have synthesized halogenated CK2β-mimicking cyclic peptides modified with the cell-penetrating peptide sC18 to mediate cellular uptake. We investigated the binding of the resulting chimeric peptides to recombinant human CK2α using a recently developed fluorescence anisotropy assay. The iodinated peptide sC18-I-Pc was identified as a potent CK2α ligand (Ki =0.622 μm). It was internalized in cells to a high extent and exhibited significant cytotoxicity toward cancerous HeLa cells (IC50 =37 μm) in contrast to non-cancerous HEK-293 cells. The attractive features and functionalities of sC18-I-Pc offer the opportunity for further improvement.
Collapse
Affiliation(s)
- Dirk Lindenblatt
- Department of Chemistry, Institute of Biochemistry, University of Cologne, Zülpicher Straße 47, 50674, Cologne, Germany
| | - Mareike Horn
- Department of Chemistry, Institute of Biochemistry, University of Cologne, Zülpicher Straße 47, 50674, Cologne, Germany
| | - Claudia Götz
- Medical Biochemistry and Molecular Biology, Saarland University, Kirrberger Str., Building 44, 66421, Homburg, Germany
| | - Karsten Niefind
- Department of Chemistry, Institute of Biochemistry, University of Cologne, Zülpicher Straße 47, 50674, Cologne, Germany
| | - Ines Neundorf
- Department of Chemistry, Institute of Biochemistry, University of Cologne, Zülpicher Straße 47, 50674, Cologne, Germany
| | - Markus Pietsch
- Institute II of Pharmacology, Center of Pharmacology, Medical Faculty, University of Cologne, Gleueler Str. 24, 50931, Cologne, Germany
| |
Collapse
|
22
|
Identification of a Potent Allosteric Inhibitor of Human Protein Kinase CK2 by Bacterial Surface Display Library Screening. Pharmaceuticals (Basel) 2017; 10:ph10010006. [PMID: 28067769 PMCID: PMC5374410 DOI: 10.3390/ph10010006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Revised: 12/24/2016] [Accepted: 12/27/2016] [Indexed: 02/06/2023] Open
Abstract
Human protein kinase CK2 has emerged as promising target for the treatment of neoplastic diseases. The vast majority of kinase inhibitors known today target the ATP binding site, which is highly conserved among kinases and hence leads to limited selectivity. In order to identify non-ATP competitive inhibitors, a 12-mer peptide library of 6 × 10⁵ variants was displayed on the surface of E. coli by autodisplay. Screening of this peptide library on variants with affinity to CK2 was performed by fluorophore-conjugated CK2 and subsequent flow cytometry. Single cell sorting of CK2-bound E. coli yielded new peptide variants, which were tested on inhibition of CK2 by a CE-based assay. Peptide B2 (DCRGLIVMIKLH) was the most potent inhibitor of both, CK2 holoenzyme and the catalytic CK2α subunit (IC50 = 0.8 µM). Using different ATP concentrations and different substrate concentrations for IC50 determination, B2 was shown to be neither ATP- nor substrate competitive. By microscale thermophoresis (MST) the KD value of B2 with CK2α was determined to be 2.16 µM, whereas no binding of B2 to CK2β-subunit was detectable. To our surprise, besides inhibition of enzymatic activity, B2 also disturbed the interaction of CK2α with CK2β at higher concentrations (≥25 µM).
Collapse
|
23
|
The New Role for an Old Kinase: Protein Kinase CK2 Regulates Metal Ion Transport. Pharmaceuticals (Basel) 2016; 9:ph9040080. [PMID: 28009816 PMCID: PMC5198054 DOI: 10.3390/ph9040080] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Revised: 12/13/2016] [Accepted: 12/16/2016] [Indexed: 12/27/2022] Open
Abstract
The pleiotropic serine/threonine protein kinase CK2 was the first kinase discovered. It is renowned for its role in cell proliferation and anti-apoptosis. The complexity of this kinase is well reflected by the findings of past decades in terms of its heterotetrameric structure, subcellular location, constitutive activity and the extensive catalogue of substrates. With the advent of non-biased high-throughput functional genomics such as genome-wide deletion mutant screening, novel aspects of CK2 functionality have been revealed. Our recent discoveries using the model organism Saccharomyces cerevisiae and mammalian cells demonstrate that CK2 regulates metal toxicity. Extensive literature search reveals that there are few but elegant works on the role of CK2 in regulating the sodium and zinc channels. As both CK2 and metal ions are key players in cell biology and oncogenesis, understanding the details of CK2’s regulation of metal ion homeostasis has a direct bearing on cancer research. In this review, we aim to garner the recent data and gain insights into the role of CK2 in metal ion transport.
Collapse
|
24
|
Götz C, Montenarh M. Protein kinase CK2 in development and differentiation. Biomed Rep 2016; 6:127-133. [PMID: 28357063 DOI: 10.3892/br.2016.829] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Accepted: 12/06/2016] [Indexed: 12/15/2022] Open
Abstract
Among the human kinomes, protein kinase CK2 (formerly termed casein kinase II) is considered to be essential, as it is implicated in the regulation of various cellular processes. Experiments with pharmacological inhibitors of the kinase activity of CK2 provide evidence that CK2 is essential for development and differentiation. Therefore, the present review addresses the role of CK2 during embryogenesis, neuronal, adipogenic, osteogenic and myogenic differentiation in established model cell lines, and in embryonic, neural and mesenchymal stem cells. CK2 kinase activity appears to be essential in the early stages of differentiation, as CK2 inhibition at early time points generally prevents differentiation. In addition, the present review reports on target proteins of CK2 in embryogenesis and differentiation.
Collapse
Affiliation(s)
- Claudia Götz
- Department of Medical Biochemistry and Molecular Biology, Saarland University, D-66424 Homburg, Germany
| | - Mathias Montenarh
- Department of Medical Biochemistry and Molecular Biology, Saarland University, D-66424 Homburg, Germany
| |
Collapse
|
25
|
Seetoh WG, Abell C. Disrupting the Constitutive, Homodimeric Protein-Protein Interface in CK2β Using a Biophysical Fragment-Based Approach. J Am Chem Soc 2016; 138:14303-14311. [PMID: 27726344 PMCID: PMC5257173 DOI: 10.1021/jacs.6b07440] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
![]()
Identifying small molecules that
induce the disruption of constitutive
protein–protein interfaces is a challenging objective. Here,
a targeted biophysical screening cascade was employed to specifically
identify small molecules that could disrupt the constitutive, homodimeric
protein–protein interface within CK2β. This approach
could potentially be applied to achieve subunit disassembly of other
homo-oligomeric proteins as a means of modulating protein function.
Collapse
Affiliation(s)
- Wei-Guang Seetoh
- Department of Chemistry, University of Cambridge , Lensfield Road, Cambridge, CB2 1EW, United Kingdom
| | - Chris Abell
- Department of Chemistry, University of Cambridge , Lensfield Road, Cambridge, CB2 1EW, United Kingdom
| |
Collapse
|
26
|
Seetoh WG, Chan DSH, Matak-Vinković D, Abell C. Mass Spectrometry Reveals Protein Kinase CK2 High-Order Oligomerization via the Circular and Linear Assembly. ACS Chem Biol 2016; 11:1511-7. [PMID: 26999075 DOI: 10.1021/acschembio.6b00064] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
CK2 is an intrinsically active protein kinase that is crucial for cellular viability. However, conventional kinase regulatory mechanisms do not apply to CK2, and its mode of regulation remains elusive. Interestingly, CK2 is known to undergo reversible ionic-strength-dependent oligomerization. Furthermore, a regulatory mechanism based on autoinhibitory oligomerization has been postulated on the basis of the observation of circular trimeric oligomers and linear CK2 assemblies in various crystal structures. Here, we employ native mass spectrometry to monitor the assembly of oligomeric CK2 species in an ionic-strength-dependent manner. A subsequent combination of ion mobility spectrometry-mass spectrometry and hydrogen-deuterium exchange mass spectrometry techniques was used to analyze the conformation of CK2 oligomers. Our findings support ionic-strength-dependent CK2 oligomerization, demonstrate the transient nature of the α/β interaction, and show that CK2 oligomerization proceeds via both the circular and linear assembly.
Collapse
Affiliation(s)
- Wei-Guang Seetoh
- Department of Chemistry, University of Cambridge, Lensfield
Road, Cambridge, CB2 1EW, United Kingdom
| | - Daniel Shiu-Hin Chan
- Department of Chemistry, University of Cambridge, Lensfield
Road, Cambridge, CB2 1EW, United Kingdom
| | - Dijana Matak-Vinković
- Department of Chemistry, University of Cambridge, Lensfield
Road, Cambridge, CB2 1EW, United Kingdom
| | - Chris Abell
- Department of Chemistry, University of Cambridge, Lensfield
Road, Cambridge, CB2 1EW, United Kingdom
| |
Collapse
|
27
|
Development of a high-throughput screening-compatible assay to identify inhibitors of the CK2α/CK2β interaction. Anal Biochem 2015; 468:4-14. [DOI: 10.1016/j.ab.2014.09.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Revised: 08/22/2014] [Accepted: 09/05/2014] [Indexed: 01/10/2023]
|
28
|
Zhou Y, Li X, Zhang N, Zhong R. Structural Basis for Low-Affinity Binding of Non-R2 Carboxylate-Substituted Tricyclic Quinoline Analogs to CK2α: Comparative Molecular Dynamics Simulation Studies. Chem Biol Drug Des 2014; 85:189-200. [DOI: 10.1111/cbdd.12372] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Revised: 04/14/2014] [Accepted: 06/02/2014] [Indexed: 12/16/2022]
Affiliation(s)
- Yue Zhou
- College of Life Science and Bioengineering; Beijing University of Technology; Beijing 100124 China
| | - Xitao Li
- School of Chemical Biology and Biotechnology; Shenzhen Graduate School; Peking University; Shenzhen 518055 China
| | - Na Zhang
- College of Life Science and Bioengineering; Beijing University of Technology; Beijing 100124 China
| | - Rugang Zhong
- College of Life Science and Bioengineering; Beijing University of Technology; Beijing 100124 China
| |
Collapse
|
29
|
Lolli G, Ranchio A, Battistutta R. Active form of the protein kinase CK2 α2β2 holoenzyme is a strong complex with symmetric architecture. ACS Chem Biol 2014; 9:366-71. [PMID: 24175891 DOI: 10.1021/cb400771y] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
CK2 is a protein kinase essential for cell viability whose activity is altered in several cancers. Its mechanisms of regulation differ from those common to other eukaryotic protein kinases and are not entirely established yet. Here we present crystal structures of the monomeric form of the α2β2 holoenzyme that allow refining a formerly proposed structural model for activity regulation by oligomerization. Previous crystal structures of the CK2 holoenzyme show an asymmetric arrangement of the two α catalytic subunits around the obligate β2 regulatory subunits. Asymmetric α2β2 tetramers are organized in trimeric rings that correspond to inactive forms of the enzyme. The new crystal structures presented here reveal the symmetric architecture of the isolated active tetramers. The dimension and the nature of the α/β interfaces configure the holoenzyme as a strong complex that does not spontaneously dissociate in solution, in accordance with the low dissociation constant (∼4 nM).
Collapse
Affiliation(s)
- Graziano Lolli
- Department
of Chemical Sciences, University of Padua, via Marzolo 1, 35131 Padova, Italy
- Venetian Institute for Molecular Medicine (VIMM), via Orus 2, 35129 Padova, Italy
| | - Alessandro Ranchio
- Department
of Chemical Sciences, University of Padua, via Marzolo 1, 35131 Padova, Italy
- Venetian Institute for Molecular Medicine (VIMM), via Orus 2, 35129 Padova, Italy
| | - Roberto Battistutta
- Department
of Chemical Sciences, University of Padua, via Marzolo 1, 35131 Padova, Italy
- Venetian Institute for Molecular Medicine (VIMM), via Orus 2, 35129 Padova, Italy
| |
Collapse
|
30
|
Identification of a novel protein interaction motif in the regulatory subunit of casein kinase 2. Mol Cell Biol 2013; 34:246-58. [PMID: 24216761 DOI: 10.1128/mcb.00968-13] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Casein kinase 2 (CK2) regulates multiple cellular processes and can promote oncogenesis. Interactions with the CK2β regulatory subunit of the enzyme target its catalytic subunit (CK2α or CK2α') to specific substrates; however, little is known about the mechanisms by which these interactions occur. We previously showed that by binding CK2β, the Epstein-Barr virus (EBV) EBNA1 protein recruits CK2 to promyelocytic leukemia (PML) nuclear bodies, where increased CK2-mediated phosphorylation of PML proteins triggers their degradation. Here we have identified a KSSR motif near the dimerization interface of CK2β as forming part of a protein interaction pocket that mediates interaction with EBNA1. We show that the EBNA1-CK2β interaction is primed by phosphorylation of EBNA1 on S393 (within a polyserine region). This phosphoserine is critical for EBNA1-induced PML degradation but does not affect EBNA1 functions in EBV replication or segregation. Using comparative proteomics of wild-type (WT) and KSSR mutant CK2β, we identified an uncharacterized cellular protein, C18orf25/ARKL1, that also binds CK2β through the KSSR motif and show that this involves a polyserine sequence resembling the CK2β binding sequence in EBNA1. Therefore, we have identified a new mechanism of CK2 interaction used by viral and cellular proteins.
Collapse
|
31
|
Zinc-dependent interaction between JAB1 and pre-S2 mutant large surface antigen of hepatitis B virus and its implications for viral hepatocarcinogenesis. J Virol 2013; 87:12675-84. [PMID: 24049181 DOI: 10.1128/jvi.01497-13] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Chronic hepatitis B virus (HBV) infection is a major cause of hepatocellular carcinoma (HCC) worldwide. The pre-S2 mutant large HBV surface protein (Δ2 LHBS), which contains an in-frame deletion of approximately 17 amino acids in LHBS, is highly associated with risks and prognoses of HBV-induced HCC. It was previously reported that Δ2 LHBS interacts with the Jun activation domain-binding protein 1 (JAB1), a zinc metalloprotease. This promotes the degradation of the cell cycle regulator p27(Kip1) and is believed to be the major mechanism for Δ2 LHBS-induced HCC. In this study, it was found that the interaction between JAB1 and Δ2 LHBS is facilitated by divalent metal Zn(2+) ions. The binding of JAB1 to Δ2 LHBS requires the JAB1/CSN5 MPN metalloenzyme (JAMM) motif and residue H138 that binds to Zn(2+) ions in JAB1. Isothermal titration calorimetry showed that Δ2 LHBS binds directly to Zn(2+) ions in a two-site binding mode. Residues H71 and H116 in Δ2 LHBS, which also contact Zn(2+) ions, are also indispensable for Δ2 LHBS-mediated p27(Kip1) degradation in human HuH7 cells. These results suggest that developing drugs that interrupt interactions between Δ2 LHBS and JAB1 can be used to mitigate Δ2 LHBS-associated risks for HCC.
Collapse
|
32
|
Raaf J, Guerra B, Neundorf I, Bopp B, Issinger OG, Jose J, Pietsch M, Niefind K. First structure of protein kinase CK2 catalytic subunit with an effective CK2β-competitive ligand. ACS Chem Biol 2013; 8:901-7. [PMID: 23474121 DOI: 10.1021/cb3007133] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The constitutively active Ser/Thr kinase CK2 (casein kinase 2) is used by tumor cells to acquire apoptosis resistance. CK2 exists as a heterotetrameric holoenzyme with two catalytic chains (CK2α) attached to a dimer of noncatalytic subunits (CK2β). A druggable cavity at the CK2β interface of CK2α allows the design of small molecules disturbing the CK2α/CK2β interaction and thus affecting activity, stability, and substrate specificity. We describe here the first structure of CK2α with an effective CK2β-competitive compound, namely, a 13-meric cyclic peptide derived from the C-terminal CK2β segment. Some well-ordered water molecules not visible in CK2 holoenzyme structures were detected at the interface. Driven mainly by enthalpy, the peptide binds with submicromolar affinity to CK2α, stimulates its catalytic activity, and reduces effectively the CK2α/CK2β affinity. The results provide a thermodynamic and structural rationalization of the peptide's CK2β-competitive functionality and pave thus the way to a peptidomimetic drug addressing the CK2α/CK2β interaction.
Collapse
Affiliation(s)
- Jennifer Raaf
- Department für Chemie,
Institut für Biochemie, Universität zu Köln, Zülpicher Straße 47, D-50674
Köln, Germany
| | - Barbara Guerra
- Institut
for Biokemi og Molekylær
Biologi, Syddansk Universitet, Campusvej
55, DK-5230 Odense, Denmark
| | - Ines Neundorf
- Department für Chemie,
Institut für Biochemie, Universität zu Köln, Zülpicher Straße 47, D-50674
Köln, Germany
| | - Bertan Bopp
- Institut für Pharmazeutische
und Medizinische Chemie, Westfälische Wilhelms-Universität Münster, PharmaCampus, Corrensstraße 48,
D-48149 Münster, Germany
| | - Olaf-Georg Issinger
- Institut
for Biokemi og Molekylær
Biologi, Syddansk Universitet, Campusvej
55, DK-5230 Odense, Denmark
| | - Joachim Jose
- Institut für Pharmazeutische
und Medizinische Chemie, Westfälische Wilhelms-Universität Münster, PharmaCampus, Corrensstraße 48,
D-48149 Münster, Germany
| | - Markus Pietsch
- Institut für Pharmakologie, Universitätsklinikum Köln, Gleueler Straße
24, D-50931 Köln, Germany
| | - Karsten Niefind
- Department für Chemie,
Institut für Biochemie, Universität zu Köln, Zülpicher Straße 47, D-50674
Köln, Germany
| |
Collapse
|
33
|
Structural and functional analysis of the flexible regions of the catalytic α-subunit of protein kinase CK2. J Struct Biol 2012; 177:382-91. [DOI: 10.1016/j.jsb.2011.12.007] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2011] [Revised: 11/28/2011] [Accepted: 12/05/2011] [Indexed: 01/27/2023]
|
34
|
Schuster I, Bernhardt R. Interactions of natural polyamines with mammalian proteins. Biomol Concepts 2011; 2:79-94. [DOI: 10.1515/bmc.2011.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
AbstractThe ubiquitously expressed natural polyamines putrescine, spermidine, and spermine are small, flexible cationic compounds that exert pleiotropic actions on various regulatory systems and, accordingly, are essentially involved in diverse life functions. These roles of polyamines result from their capability to interact with negatively charged regions of all major classes of biomolecules, which might act in response by changing their structures and functions. The present review deals with polyamine-protein interactions, thereby focusing on mammalian proteins. We discuss the various modes in which polyamines can interact with proteins, describe major types of affected functions illustrated by representative examples of involved proteins, and support information with respective structural evidence from elucidated three-dimensional structures. A specific focus is put on polyamine interactions at protein surfaces that can modulate the aggregation of proteins to organized structural networks as well as to toxic aggregates and, moreover, can play a role in important transient protein-protein interactions.
Collapse
Affiliation(s)
- Inge Schuster
- 1Institute for Theoretical Chemistry, University Vienna, A-1090 Vienna, Austria
| | - Rita Bernhardt
- 2Institute of Biochemistry, Saarland University, Campus B2.2, D-66123 Saarbrücken, Germany
| |
Collapse
|
35
|
Bischoff N, Olsen B, Raaf J, Bretner M, Issinger OG, Niefind K. Structure of the human protein kinase CK2 catalytic subunit CK2α' and interaction thermodynamics with the regulatory subunit CK2β. J Mol Biol 2011; 407:1-12. [PMID: 21241709 DOI: 10.1016/j.jmb.2011.01.020] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2010] [Revised: 01/04/2011] [Accepted: 01/11/2011] [Indexed: 10/18/2022]
Abstract
Protein kinase CK2 (formerly "casein kinase 2") is composed of a central dimer of noncatalytic subunits (CK2β) binding two catalytic subunits. In humans, there are two isoforms of the catalytic subunit (and an additional splicing variant), one of which (CK2α) is well characterized. To supplement the limited biochemical knowledge about the second paralog (CK2α'), we developed a well-soluble catalytically active full-length mutant of human CK2α', characterized it by Michaelis-Menten kinetics and isothermal titration calorimetry, and determined its crystal structure to a resolution of 2 Å. The affinity of CK2α' for CK2β is about 12 times lower than that of CK2α and is less driven by enthalpy. This result fits the observation that the β4/β5 loop, a key element of the CK2α/CK2β interface, adopts an open conformation in CK2α', while in CK2α, it opens only after assembly with CK2β. The open β4/β5 loop in CK2α' is stabilized by two elements that are absent in CK2α: (1) the extension of the N-terminal β-sheet by an additional β-strand, and (2) the filling of a conserved hydrophobic cavity between the β4/β5 loop and helix αC by a tryptophan residue. Moreover, the interdomain hinge region of CK2α' adopts a fully functional conformation, while unbound CK2α is often found with a nonproductive hinge conformation that is overcome only by CK2β binding. Taken together, CK2α' exhibits a significantly lower affinity for CK2β than CK2α; moreover, in functionally critical regions, it is less dependent on CK2β to obtain a fully functional conformation.
Collapse
Affiliation(s)
- Nils Bischoff
- Department für Chemie, Institut für Biochemie, Universität zu Köln, Zülpicher Straße 47, D-50674 Köln, Germany
| | | | | | | | | | | |
Collapse
|
36
|
Raaf J, Bischoff N, Klopffleisch K, Brunstein E, Olsen BB, Vilk G, Litchfield DW, Issinger OG, Niefind K. Interaction between CK2α and CK2β, the subunits of protein kinase CK2: thermodynamic contributions of key residues on the CK2α surface. Biochemistry 2010; 50:512-22. [PMID: 21142136 DOI: 10.1021/bi1013563] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The protein Ser/Thr kinase CK2 (former name: casein kinase II) exists predominantly as a heterotetrameric holoenzyme composed of two catalytic subunits (CK2α) bound to a dimer of noncatalytic subunits (CK2β). We undertook a study to further understand how these subunits interact to form the tetramer. To this end, we used recombinant, C-terminal truncated forms of human CK2 subunits that are able to form the holoenzyme. We analyzed the interaction thermodynamics between the binding of CK2α and CK2β as well as the impact of changes in temperature, pH, and the ionization enthalpy of the buffer using isothermal titration calorimetry (ITC). With structure-guided alanine scanning mutagenesis we truncated individual side chains in the hydrophobic amino acid cluster located within the CK2α interface to identify experimentally the amino acids that dominate affinity. The ITC results indicate that Leu41 or Phe54 single mutations were most disruptive to binding of CK2β. Additionally, these CK2α mutants retained their kinase activity. Furthermore, the substitution of Leu41 in combination with Phe54 showed that the individual mutations were not additive, suggesting that the cooperative action of both residues played a role. Interestingly, the replacement of Ile69, which has a central position in the interaction surface of CK2α, only had modest effects. The differences between Leu41, Phe54, and Ile69 in interaction relevance correlate with solvent accessibility changes during the transition from unbound to CK2β-bound CK2α. Identifying residues on CK2α that play a key role in CK2α/CK2β interactions is important for the future generation of small molecule drug design.
Collapse
Affiliation(s)
- Jennifer Raaf
- Department für Chemie, Institut für Biochemie, Universität zu Köln, Zülpicher Strasse 47, Köln, Germany
| | | | | | | | | | | | | | | | | |
Collapse
|
37
|
Abstract
CK2 is a pleiotropic, ubiquitous, and constitutively active protein kinase (PK), with both cytosolic and nuclear localization in most mammalian cells. The holoenzyme is generally composed of two catalytic (alpha and/or alpha') and two regulatory (beta) subunits, but the free alpha/alpha' subunits are catalytically active by themselves and can be present in cells under some circumstances. CK2 catalyzes the phosphorylation of more than 300 substrates characterized by multiple acidic residues surrounding the phosphor-acceptor amino acid, and, consequently, it plays a key role in several physiological and pathological processes. But how can one kinase orchestrate all these tasks faithfully? How is it possible that one kinase can, despite all pleiotropic characteristics of PKs in general, be involved in so many different biochemical events? Is CK2 a druggable target? Several questions are still to be clearly answered, and this review is an occasion for a fruitful discussion.
Collapse
Affiliation(s)
- Giorgio Cozza
- Molecular Modeling Section, Dipartimento di Scienze Farmaceutiche, Università di Padova, via Marzolo 5, Padova, Italy
| | | | | |
Collapse
|
38
|
Survey of the year 2008: applications of isothermal titration calorimetry. J Mol Recognit 2010; 23:395-413. [DOI: 10.1002/jmr.1025] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
|
39
|
Niefind K, Issinger OG. Conformational plasticity of the catalytic subunit of protein kinase CK2 and its consequences for regulation and drug design. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2009; 1804:484-92. [PMID: 19796713 DOI: 10.1016/j.bbapap.2009.09.022] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2009] [Revised: 09/16/2009] [Accepted: 09/21/2009] [Indexed: 11/30/2022]
Abstract
At the first glance CK2alpha, the catalytic subunit of protein kinase CK2, is a rigid molecule: in contrast to many eukaryotic protein kinases in CK2alpha the canonical regulatory key elements like the activation segment occur exclusively in their typical active conformations. This observation fits well to the constitutive activity of the enzyme, meaning, its independence from phosphorylation or other characteristic control factors. Most CK2alpha structures are based on the enzyme from Zea mays, supplemented by an increasing number of human CK2alpha structures. In the latter a surprising plasticity of important ATP-binding elements - the interdomain hinge region and the glycine-rich loop - was discovered. In fully active CK2alpha the hinge region is open and does not anchor the ATP ribose, but alternatively it can adopt a closed conformation, form hydrogen bonds to the ribose moiety and thus retract the gamma-phospho group from its functional position. In addition to this partially inactive state human CK2alpha was recently found in a fully inactive conformation. It is incompatible with ATP-binding due to a combination of a closed hinge and a collapse of the glycine-rich loop into the ATP cavity. These conformational transitions are apparently correlated with the occupation state of a remote docking site located at the interface to the non-catalytic subunit CK2beta: if CK2beta blocks this site, the fully active conformation of CK2alpha is stabilized, while the binding of certain small molecule seems to favour the partially and fully inactive states. This observation may be exploited to design effective and selective CK2 inhibitors.
Collapse
Affiliation(s)
- Karsten Niefind
- Institute of Biochemistry, Department of Chemistry, University of Cologne, Zuelpicher Str. 47, D-50674 Cologne, Germany.
| | | |
Collapse
|
40
|
Quinalizarin as a potent, selective and cell-permeable inhibitor of protein kinase CK2. Biochem J 2009; 421:387-95. [PMID: 19432557 DOI: 10.1042/bj20090069] [Citation(s) in RCA: 125] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Emodin (1,3,8-trihydroxy-6-methyl-anthraquinone) is a moderately potent and poorly selective inhibitor of protein kinase CK2, one of the most pleiotropic serine/threonine protein kinases, implicated in neoplasia and in other global diseases. By virtual screening of the MMS (Molecular Modeling Section) database, we have now identified quinalizarin (1,2,5,8-tetrahydroxyanthraquinone) as an inhibitor of CK2 that is more potent and selective than emodin. CK2 inhibition by quinalizarin is competitive with respect to ATP, with a Ki value of approx. 50 nM. Tested at 1 microM concentration on a panel of 75 protein kinases, quinalizarin drastically inhibits only CK2, with a promiscuity score (11.1), which is the lowest ever reported so far for a CK2 inhibitor. Especially remarkable is the ability of quinalizarin to discriminate between CK2 and a number of kinases, notably DYRK1a (dual-specificity tyrosine-phosphorylated and -regulated kinase), PIM (provirus integration site for Moloney murine leukaemia virus) 1, 2 and 3, HIPK2 (homeodomain-interacting protein kinase-2), MNK1 [MAPK (mitogen-activated protein kinase)-interacting kinase 1], ERK8 (extracellular-signal-regulated kinase 8) and PKD1 (protein kinase D 1), which conversely tend to be inhibited as drastically as CK2 by commercially available CK2 inhibitors. The determination of the crystal structure of a complex between quinalizarin and CK2alpha subunit highlights the relevance of polar interactions in stabilizing the binding, an unusual characteristic for a CK2 inhibitor, and disclose other structural features which may account for the narrow selectivity of this compound. Tested on Jurkat cells, quinalizarin proved able to inhibit endogenous CK2 and to induce apoptosis more efficiently than the commonly used CK2 inhibitors TBB (4,5,6,7-tetrabromo-1H-benzotriazole) and DMAT (2-dimethylamino-4,5,6,7-tetrabromo-1H-benzimidazole).
Collapse
|
41
|
Raaf J, Issinger OG, Niefind K. First inactive conformation of CK2 alpha, the catalytic subunit of protein kinase CK2. J Mol Biol 2009; 386:1212-21. [PMID: 19361447 DOI: 10.1016/j.jmb.2009.01.033] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2008] [Accepted: 01/20/2009] [Indexed: 11/25/2022]
Abstract
The Ser/Thr kinase casein kinase 2 (CK2) is a heterotetrameric enzyme composed of two catalytic chains (CK2alpha, catalytic subunit of CK2) attached to a dimer of two noncatalytic subunits (CK2beta, noncatalytic subunit of CK2). CK2alpha belongs to the superfamily of eukaryotic protein kinases (EPKs). To function as regulatory key components, EPKs normally exist in inactive ground states and are activated only upon specific signals. Typically, this activation is accompanied by large conformational changes in helix alpha C and in the activation segment, leading to a characteristic arrangement of catalytic key elements. For CK2alpha, however, no strict physiological control of activity is known. Accordingly, CK2alpha was found so far exclusively in the characteristic conformation of active EPKs, which is, in this case, additionally stabilized by a unique intramolecular contact between the N-terminal segment on one side, and helix alpha C and the activation segment on the other side. We report here the structure of a C-terminally truncated variant of human CK2alpha in which the enzyme adopts a decidedly inactive conformation for the first time. In this CK2alpha structure, those regulatory key regions still are in their active positions. Yet the glycine-rich ATP-binding loop, which is normally part of the canonical anti-parallel beta-sheet, has collapsed into the ATP-binding site so that ATP is excluded from binding; specifically, the side chain of Arg47 occupies the ribose region of the ATP site and Tyr50, the space required by the triphospho moiety. We discuss some factors that may support or disfavor this inactive conformation, among them coordination of small molecules at a remote cavity at the CK2alpha/CK2beta interaction region and binding of a CK2beta dimer. The latter stabilizes the glycine-rich loop in the extended active conformation known from the majority of CK2alpha structures. Thus, the novel inactive conformation for the first time provides a structural basis for the stimulatory impact of CK2beta on CK2alpha.
Collapse
Affiliation(s)
- Jennifer Raaf
- Universität zu Köln, Institut für Biochemie, Zülpicher Str. 47, D-50674 Köln, Germany
| | | | | |
Collapse
|