1
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Pluta AJ, Studniarek C, Murphy S, Norbury CJ. Cyclin-dependent kinases: Masters of the eukaryotic universe. WILEY INTERDISCIPLINARY REVIEWS. RNA 2023; 15:e1816. [PMID: 37718413 PMCID: PMC10909489 DOI: 10.1002/wrna.1816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 07/21/2023] [Accepted: 08/03/2023] [Indexed: 09/19/2023]
Abstract
A family of structurally related cyclin-dependent protein kinases (CDKs) drives many aspects of eukaryotic cell function. Much of the literature in this area has considered individual members of this family to act primarily either as regulators of the cell cycle, the context in which CDKs were first discovered, or as regulators of transcription. Until recently, CDK7 was the only clear example of a CDK that functions in both processes. However, new data points to several "cell-cycle" CDKs having important roles in transcription and some "transcriptional" CDKs having cell cycle-related targets. For example, novel functions in transcription have been demonstrated for the archetypal cell cycle regulator CDK1. The increasing evidence of the overlap between these two CDK types suggests that they might play a critical role in coordinating the two processes. Here we review the canonical functions of cell-cycle and transcriptional CDKs, and provide an update on how these kinases collaborate to perform important cellular functions. We also provide a brief overview of how dysregulation of CDKs contributes to carcinogenesis, and possible treatment avenues. This article is categorized under: RNA Interactions with Proteins and Other Molecules > RNA-Protein Complexes RNA Processing > 3' End Processing RNA Processing > Splicing Regulation/Alternative Splicing.
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Affiliation(s)
| | | | - Shona Murphy
- Sir William Dunn School of PathologyUniversity of OxfordOxfordUK
| | - Chris J. Norbury
- Sir William Dunn School of PathologyUniversity of OxfordOxfordUK
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2
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Enserink JM, Chymkowitch P. Cell Cycle-Dependent Transcription: The Cyclin Dependent Kinase Cdk1 Is a Direct Regulator of Basal Transcription Machineries. Int J Mol Sci 2022; 23:ijms23031293. [PMID: 35163213 PMCID: PMC8835803 DOI: 10.3390/ijms23031293] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 01/22/2022] [Accepted: 01/22/2022] [Indexed: 12/21/2022] Open
Abstract
The cyclin-dependent kinase Cdk1 is best known for its function as master regulator of the cell cycle. It phosphorylates several key proteins to control progression through the different phases of the cell cycle. However, studies conducted several decades ago with mammalian cells revealed that Cdk1 also directly regulates the basal transcription machinery, most notably RNA polymerase II. More recent studies in the budding yeast Saccharomyces cerevisiae have revisited this function of Cdk1 and also revealed that Cdk1 directly controls RNA polymerase III activity. These studies have also provided novel insight into the physiological relevance of this process. For instance, cell cycle-stage-dependent activity of these complexes may be important for meeting the increased demand for various proteins involved in housekeeping, metabolism, and protein synthesis. Recent work also indicates that direct regulation of the RNA polymerase II machinery promotes cell cycle entry. Here, we provide an overview of the regulation of basal transcription by Cdk1, and we hypothesize that the original function of the primordial cell-cycle CDK was to regulate RNAPII and that it later evolved into specialized kinases that govern various aspects of the transcription machinery and the cell cycle.
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Affiliation(s)
- Jorrit M. Enserink
- Section for Biochemistry and Molecular Biology, Faculty of Mathematics and Natural Sciences, University of Oslo, 0316 Oslo, Norway
- Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, 0379 Oslo, Norway
- Centre for Cancer Cell Reprogramming, Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, 0318 Oslo, Norway
- Correspondence: (J.M.E.); (P.C.)
| | - Pierre Chymkowitch
- Section for Biochemistry and Molecular Biology, Faculty of Mathematics and Natural Sciences, University of Oslo, 0316 Oslo, Norway
- Department of Microbiology, Oslo University Hospital, 0372 Oslo, Norway
- Correspondence: (J.M.E.); (P.C.)
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3
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Ellederova Z, Del Rincon S, Koncicka M, Susor A, Kubelka M, Sun D, Spruck C. CKS1 Germ Line Exclusion Is Essential for the Transition from Meiosis to Early Embryonic Development. Mol Cell Biol 2019; 39:e00590-18. [PMID: 30988159 PMCID: PMC6580707 DOI: 10.1128/mcb.00590-18] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Revised: 01/25/2019] [Accepted: 04/04/2019] [Indexed: 12/11/2022] Open
Abstract
Cell division cycle (Cdc) kinase subunit (CKS) proteins bind cyclin-dependent kinases (CDKs) and play important roles in cell division control and development, though their precise molecular functions are not fully understood. Mammals express two closely related paralogs called CKS1 and CKS2, but only CKS2 is expressed in the germ line, indicating that it is solely responsible for regulating CDK functions in meiosis. Using cks2-/- knockout mice, we show that CKS2 is a crucial regulator of maturation-promoting factor (MPF; CDK1-cyclin A/B) activity in meiosis. cks2-/- oocytes display reduced and delayed MPF activity during meiotic progression, leading to defects in germinal vesicle breakdown (GVBD), anaphase-promoting complex/cyclosome (APC/C) activation, and meiotic spindle assembly. cks2-/- germ cells express significantly reduced levels of the MPF components CDK1 and cyclins A1/B1. Additionally, injection of MPF plus CKS2, but not MPF alone, restored normal GVBD in cks2-/- oocytes, demonstrating that GVBD is driven by a CKS2-dependent function of MPF. Moreover, we generated cks2cks1/cks1 knock-in mice and found that CKS1 can compensate for CKS2 in meiosis in vivo, but homozygous embryos arrested development at the 2- to 5-cell stage. Collectively, our results show that CKS2 is a crucial regulator of MPF functions in meiosis and that its paralog, CKS1, must be excluded from the germ line for proper embryonic development.
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Affiliation(s)
- Zdenka Ellederova
- Tumor Initiation and Maintenance Program, Sanford | Burnham | Prebys Medical Discovery Institute, La Jolla, California, USA
- Laboratory of Cell Regeneration and Plasticity, Institute of Animal Physiology and Genetics, Czech Academy of Science, Libechov, Czech Republic
| | - Sonia Del Rincon
- Tumor Initiation and Maintenance Program, Sanford | Burnham | Prebys Medical Discovery Institute, La Jolla, California, USA
- Gerald Bronfman Department of Oncology, McGill University Lady Davis Institute, Segal Cancer Centre-Jewish General Hospital, Montreal, Quebec, Canada
| | - Marketa Koncicka
- Laboratory of Biochemistry and Molecular Biology of Germ Cells, Institute of Animal Physiology and Genetics, Czech Academy of Science, Libechov, Czech Republic
- Department of Cell Biology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Andrej Susor
- Laboratory of Biochemistry and Molecular Biology of Germ Cells, Institute of Animal Physiology and Genetics, Czech Academy of Science, Libechov, Czech Republic
| | - Michal Kubelka
- Laboratory of Biochemistry and Molecular Biology of Germ Cells, Institute of Animal Physiology and Genetics, Czech Academy of Science, Libechov, Czech Republic
| | - Dahui Sun
- Tumor Initiation and Maintenance Program, Sanford | Burnham | Prebys Medical Discovery Institute, La Jolla, California, USA
| | - Charles Spruck
- Tumor Initiation and Maintenance Program, Sanford | Burnham | Prebys Medical Discovery Institute, La Jolla, California, USA
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4
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Grey W, Ivey A, Milne TA, Haferlach T, Grimwade D, Uhlmann F, Voisset E, Yu V. The Cks1/Cks2 axis fine-tunes Mll1 expression and is crucial for MLL-rearranged leukaemia cell viability. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2018; 1865:105-116. [PMID: 28939057 PMCID: PMC5701546 DOI: 10.1016/j.bbamcr.2017.09.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Revised: 09/09/2017] [Accepted: 09/17/2017] [Indexed: 12/25/2022]
Abstract
The Cdc28 protein kinase subunits, Cks1 and Cks2, play dual roles in Cdk-substrate specificity and Cdk-independent protein degradation, in concert with the E3 ubiquitin ligase complexes SCFSkp2 and APCCdc20. Notable targets controlled by Cks include p27 and Cyclin A. Here, we demonstrate that Cks1 and Cks2 proteins interact with both the MllN and MllC subunits of Mll1 (Mixed-lineage leukaemia 1), and together, the Cks proteins define Mll1 levels throughout the cell cycle. Overexpression of CKS1B and CKS2 is observed in multiple human cancers, including various MLL-rearranged (MLLr) AML subtypes. To explore the importance of MLL-Fusion Protein regulation by CKS1/2, we used small molecule inhibitors (MLN4924 and C1) to modulate their protein degradation functions. These inhibitors specifically reduced the proliferation of MLLr cell lines compared to primary controls. Altogether, this study uncovers a novel regulatory pathway for MLL1, which may open a new therapeutic approach to MLLr leukaemia.
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Affiliation(s)
- William Grey
- Department of Medical and Molecular Genetics, King's College London, Faculty of Life Sciences and Medicine, London, UK.
| | - Adam Ivey
- Department of Medical and Molecular Genetics, King's College London, Faculty of Life Sciences and Medicine, London, UK
| | - Thomas A Milne
- MRC Molecular Haematology Unit, Weatherall Institute of Molecular Medicine, NIHR Oxford Biomedical Research Centre Programme, University of Oxford, UK
| | | | - David Grimwade
- Department of Medical and Molecular Genetics, King's College London, Faculty of Life Sciences and Medicine, London, UK
| | - Frank Uhlmann
- Chromosome Segregation Laboratory, The Francis Crick Institute, London, UK
| | - Edwige Voisset
- Department of Medical and Molecular Genetics, King's College London, Faculty of Life Sciences and Medicine, London, UK.
| | - Veronica Yu
- Department of Medical and Molecular Genetics, King's College London, Faculty of Life Sciences and Medicine, London, UK
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5
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CKS Proteins Promote Checkpoint Recovery by Stimulating Phosphorylation of Treslin. Mol Cell Biol 2017; 37:MCB.00344-17. [PMID: 28739856 DOI: 10.1128/mcb.00344-17] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Accepted: 07/11/2017] [Indexed: 01/01/2023] Open
Abstract
CKS proteins are small (9-kDa) polypeptides that bind to a subset of the cyclin-dependent kinases. The two paralogs expressed in mammals, Cks1 and Cks2, share an overlapping function that is essential for early development. However, both proteins are frequently overexpressed in human malignancy. It has been shown that CKS protein overexpression overrides the replication stress checkpoint, promoting continued origin firing. This finding has led to the proposal that CKS protein-dependent checkpoint override allows premalignant cells to evade oncogene stress barriers, providing a causal link to oncogenesis. Here, we provide mechanistic insight into how overexpression of CKS proteins promotes override of the replication stress checkpoint. We show that CKS proteins greatly enhance the ability of Cdk2 to phosphorylate the key replication initiation protein treslin in vitro Furthermore, stimulation of treslin phosphorylation does not occur by the canonical adapter mechanism demonstrated for other substrates, as cyclin-dependent kinase (CDK) binding-defective mutants are capable of stimulating treslin phosphorylation. This effect is recapitulated in vivo, where silencing of Cks1 and Cks2 decreases treslin phosphorylation, and overexpression of wild-type or CDK binding-defective Cks2 prevents checkpoint-dependent dephosphorylation of treslin. Finally, we provide evidence that the role of CKS protein-dependent checkpoint override involves recovery from checkpoint-mediated arrest of DNA replication.
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6
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Yue X, Que Y, Deng S, Xu L, Oses-Ruiz M, Talbot NJ, Peng Y, Wang Z. The cyclin dependent kinase subunit Cks1 is required for infection-associated development of the rice blast fungusMagnaporthe oryzae. Environ Microbiol 2017; 19:3959-3981. [DOI: 10.1111/1462-2920.13796] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Revised: 03/30/2017] [Accepted: 05/08/2017] [Indexed: 11/27/2022]
Affiliation(s)
- Xiaofeng Yue
- State Key Laboratory for Rice Biology; Institute of Biotechnology, Zhejiang University; Hangzhou 310058, China
| | - Yawei Que
- State Key Laboratory for Rice Biology; Institute of Biotechnology, Zhejiang University; Hangzhou 310058, China
| | - Shuzhen Deng
- State Key Laboratory for Rice Biology; Institute of Biotechnology, Zhejiang University; Hangzhou 310058, China
| | - Lin Xu
- State Key Laboratory for Rice Biology; Institute of Biotechnology, Zhejiang University; Hangzhou 310058, China
| | - Miriam Oses-Ruiz
- School of Biosciences; University of Exeter, Geoffrey Pope Building; Exeter EX4 4QD UK
| | - Nicholas J. Talbot
- School of Biosciences; University of Exeter, Geoffrey Pope Building; Exeter EX4 4QD UK
| | - Youliang Peng
- State Key Laboratory of Agribiotechnology and MOA Key Laboratory of Plant Pathology; China Agricultural University; Beijing 100193, People's Republic of China
| | - Zhengyi Wang
- State Key Laboratory for Rice Biology; Institute of Biotechnology, Zhejiang University; Hangzhou 310058, China
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7
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Bai F, Morcos F, Cheng RR, Jiang H, Onuchic JN. Elucidating the druggable interface of protein-protein interactions using fragment docking and coevolutionary analysis. Proc Natl Acad Sci U S A 2016; 113:E8051-E8058. [PMID: 27911825 PMCID: PMC5167203 DOI: 10.1073/pnas.1615932113] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Protein-protein interactions play a central role in cellular function. Improving the understanding of complex formation has many practical applications, including the rational design of new therapeutic agents and the mechanisms governing signal transduction networks. The generally large, flat, and relatively featureless binding sites of protein complexes pose many challenges for drug design. Fragment docking and direct coupling analysis are used in an integrated computational method to estimate druggable protein-protein interfaces. (i) This method explores the binding of fragment-sized molecular probes on the protein surface using a molecular docking-based screen. (ii) The energetically favorable binding sites of the probes, called hot spots, are spatially clustered to map out candidate binding sites on the protein surface. (iii) A coevolution-based interface interaction score is used to discriminate between different candidate binding sites, yielding potential interfacial targets for therapeutic drug design. This approach is validated for important, well-studied disease-related proteins with known pharmaceutical targets, and also identifies targets that have yet to be studied. Moreover, therapeutic agents are proposed by chemically connecting the fragments that are strongly bound to the hot spots.
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Affiliation(s)
- Fang Bai
- Center for Theoretical Biological Physics, Rice University, Houston, TX 77005
| | - Faruck Morcos
- Department of Biological Sciences, University of Texas at Dallas, Dallas, TX 75080
- Department of Bioengineering, University of Texas at Dallas, Dallas, TX 75080
- Center for Systems Biology, University of Texas at Dallas, Dallas, TX 75080
| | - Ryan R Cheng
- Center for Theoretical Biological Physics, Rice University, Houston, TX 77005
| | - Hualiang Jiang
- Drug Discovery and Design Center, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China;
| | - José N Onuchic
- Center for Theoretical Biological Physics, Rice University, Houston, TX 77005;
- Department of Physics and Astronomy, Rice University, Houston, TX 77005
- Department of Chemistry, Rice University, Houston, TX 77005
- Department of Biosciences, Rice University, Houston, TX 77005
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8
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del Rincón SV, Widschwendter M, Sun D, Ekholm-Reed S, Tat J, Teixeira LK, Ellederova Z, Grolieres E, Reed SI, Spruck C. Cks overexpression enhances chemotherapeutic efficacy by overriding DNA damage checkpoints. Oncogene 2015; 34:1961-7. [PMID: 24858038 PMCID: PMC4245389 DOI: 10.1038/onc.2014.137] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2013] [Revised: 03/27/2014] [Accepted: 03/28/2014] [Indexed: 12/12/2022]
Abstract
Cdc kinase subunit (Cks) proteins Cks1 and Cks2 are adaptor-like proteins that bind many cyclin-dependent kinases. A wealth of clinical data has shown that Cks proteins are overexpressed in many types of human cancers and this often correlates with increased tumor aggressiveness. Previously, we showed that Cks overexpression abrogates the intra-S-phase checkpoint, a major barrier to oncogene-mediated transformation. Interestingly, the intra-S-phase checkpoint is crucial for the cellular response to replication stress, a major pathway of apoptosis induction by many chemotherapeutic agents. Here, we demonstrate cancer cells that overexpress Cks1 or Cks2 override the intra-S-phase checkpoint in the presence of replication stress-inducing chemotherapies such as 5-Fluorouracil (5-FU) and methotrexate (MTX) leading to enhanced sensitivity in vitro and in vivo. Furthermore, enforced expression of Cks1 in an MTX-resistant breast cancer cell line was found to restore drug sensitivity. Our results suggest that Cks proteins are important determinants of apoptosis induction of replication stress-inducing chemotherapies such as 5-FU.
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Affiliation(s)
- Sonia V. del Rincón
- Tumor Initiation and Maintenance Program, Cancer Center, Sanford-Burnham Medical Research Institute, La Jolla, California, USA
| | | | - Dahui Sun
- Tumor Initiation and Maintenance Program, Cancer Center, Sanford-Burnham Medical Research Institute, La Jolla, California, USA
| | - Susanna Ekholm-Reed
- Department of Molecular Biology, The Scripps Research Institute, La Jolla, California, USA
| | - John Tat
- Department of Molecular Biology, The Scripps Research Institute, La Jolla, California, USA
| | - Leonardo K. Teixeira
- Department of Molecular Biology, The Scripps Research Institute, La Jolla, California, USA
| | - Zdenka Ellederova
- Tumor Initiation and Maintenance Program, Cancer Center, Sanford-Burnham Medical Research Institute, La Jolla, California, USA
| | - Elise Grolieres
- Tumor Initiation and Maintenance Program, Cancer Center, Sanford-Burnham Medical Research Institute, La Jolla, California, USA
| | - Steven I. Reed
- Department of Molecular Biology, The Scripps Research Institute, La Jolla, California, USA
| | - Charles Spruck
- Tumor Initiation and Maintenance Program, Cancer Center, Sanford-Burnham Medical Research Institute, La Jolla, California, USA
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9
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Cks confers specificity to phosphorylation-dependent CDK signaling pathways. Nat Struct Mol Biol 2013; 20:1407-14. [PMID: 24186063 DOI: 10.1038/nsmb.2707] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2013] [Accepted: 09/11/2013] [Indexed: 12/12/2022]
Abstract
Cks is an evolutionarily conserved protein that regulates cyclin-dependent kinase (CDK) activity. Clarifying the underlying mechanisms and cellular contexts of Cks function is critical because Cks is essential for proper cell growth, and its overexpression has been linked to cancer. We observe that budding-yeast Cks associates with select phosphorylated sequences in cell cycle-regulatory proteins. We characterize the molecular interactions responsible for this specificity and demonstrate that Cks enhances CDK activity in response to specific priming phosphosites. Identification of the binding consensus sequence allows us to identify putative Cks-directed CDK substrates and binding partners. We characterize new Cks-binding sites in the mitotic regulator Wee1 and discover a new role for Cks in regulating CDK activity at mitotic entry. Together, our results portray Cks as a multifunctional phosphoadaptor that serves as a specificity factor for CDK activity.
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10
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Jeronimo C, Bataille AR, Robert F. The Writers, Readers, and Functions of the RNA Polymerase II C-Terminal Domain Code. Chem Rev 2013; 113:8491-522. [DOI: 10.1021/cr4001397] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- Célia Jeronimo
- Institut de recherches cliniques de Montréal, Montréal, Québec,
Canada H2W 1R7
| | - Alain R. Bataille
- Institut de recherches cliniques de Montréal, Montréal, Québec,
Canada H2W 1R7
| | - François Robert
- Institut de recherches cliniques de Montréal, Montréal, Québec,
Canada H2W 1R7
- Département
de Médecine,
Faculté de Médecine, Université de Montréal, Montréal, Québec,
Canada H3T 1J4
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11
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Cks1 enhances transcription efficiency at the GAL1 locus by linking the Paf1 complex to the 19S proteasome. EUKARYOTIC CELL 2013; 12:1192-201. [PMID: 23825181 DOI: 10.1128/ec.00151-13] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Cks1 was originally identified based on genetic interactions with CDC28, the gene that encodes Cdk1 in the budding yeast Saccharomyces cerevisiae. Subsequent work has shown that Cks1 binds Cdc28 and modulates its activity against certain substrates. However, the Cks1/Cdc28 complex also has a role in transcriptional chromatin remodeling not related to kinase activity. In order to elucidate protein networks associated with Cks1 transcriptional functions, proteomic analysis was performed on immunoaffinity-purified Cks1, identifying a physical interaction with the Paf1 complex. Specifically, we found that the Paf1 complex component Rtf1 interacts directly with Cks1 and that this interaction is essential for efficient recruitment of Cks1 to chromatin in the context of GAL1 gene induction. We further found that Cks1 in this capacity serves as an adaptor allowing Rtf1 to recruit 19S proteasome particles, shown to be required for efficient RNA production from some rapidly inducible genes such as GAL1.
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12
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Khattar V, Thottassery JV. Cks1: Structure, Emerging Roles and Implications in Multiple Cancers. ACTA ACUST UNITED AC 2013; 4:1341-1354. [PMID: 24563807 PMCID: PMC3930463 DOI: 10.4236/jct.2013.48159] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Deregulation of the cell cycle results in loss of normal control mechanisms that prevent aberrant cell proliferation and cancer progression. Regulation of the cell cycle is a highly complex process with many layers of control. One of these mechanisms involves timely degradation of CDK inhibitors (CKIs) like p27Kip1 by the ubiquitin proteasomal system (UPS). Cks1 is a 9 kDa protein which is frequently overexpressed in different tumor subtypes, and has pleiotropic roles in cell cycle progression, many of which remain to be fully characterized. One well characterized molecular role of Cks1 is that of an essential adaptor that regulates p27Kip1 abundance by facilitating its interaction with the SCF-Skp2 E3 ligase which appends ubiquitin to p27Kip1 and targets it for degradation through the UPS. In addition, emerging research has uncovered p27Kip1-independent roles of Cks1 which have provided crucial insights into how it may be involved in cancer progression. We review here the structural features of Cks1 and their functional implications, and also some recently identified Cks1 roles and their involvement in breast and other cancers.
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Affiliation(s)
| | - Jaideep V Thottassery
- Southern Research Institute, Birmingham, USA ; University of Alabama Comprehensive Cancer Center, Birmingham, USA
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13
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Chymkowitch P, Enserink JM. The cell cycle rallies the transcription cycle: Cdc28/Cdk1 is a cell cycle-regulated transcriptional CDK. Transcription 2012; 4:3-6. [PMID: 23131667 DOI: 10.4161/trns.22456] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
In the budding yeast Saccharomyces cerevisiae, the cyclin-dependent kinases (CDKs) Kin28, Bur1 and Ctk1 regulate basal transcription by phosphorylating the carboxyl-terminal domain (CTD) of RNA polymerase II. However, very little is known about the involvement of the cell cycle CDK Cdc28 in the transcription process. We have recently shown that, upon cell cycle entry, Cdc28 kinase activity boosts transcription of a subset of genes by directly stimulating the basal transcription machinery. Here, we discuss the biological significance of this finding and give our view of the kinase-dependent role of Cdc28 in regulation of RNA polymerase II.
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Affiliation(s)
- Pierre Chymkowitch
- Department of Molecular Biology, Institute of Medical Microbiology and Centre for Molecular Biology and Neuroscience, Oslo University Hospital, Oslo, Norway
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14
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The CDK subunit CKS2 counteracts CKS1 to control cyclin A/CDK2 activity in maintaining replicative fidelity and neurodevelopment. Dev Cell 2012; 23:356-70. [PMID: 22898779 PMCID: PMC3898080 DOI: 10.1016/j.devcel.2012.06.018] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2011] [Revised: 05/16/2012] [Accepted: 06/28/2012] [Indexed: 01/09/2023]
Abstract
CKS proteins are evolutionarily conserved cyclin-dependent kinase (CDK) subunits whose functions are incompletely understood. Mammals have two CKS proteins. CKS1 acts as a cofactor to the ubiquitin ligase complex SCFSKP2 to promote degradation of CDK inhibitors, such as p27. Little is known about the role of the closely related CKS2. Using a Cks2−/− knockout mouse model, we show that CKS2 counteracts CKS1 and stabilizes p27. Unopposed CKS1 activity in Cks2−/− cells leads to loss of p27. The resulting unrestricted cyclin A/CDK2 activity is accompanied by shortening of the cell cycle, increased replication fork velocity, and DNA damage. In vivo, Cks2−/− cortical progenitor cells are limited in their capacity to differentiate into mature neurons, a phenotype akin to animals lacking p27. We propose that the balance between CKS2 and CKS1 modulates p27 degradation, and with it cyclin A/CDK2 activity, to safeguard replicative fidelity and control neuronal differentiation.
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15
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Enserink JM. Chemical genetics: budding yeast as a platform for drug discovery and mapping of genetic pathways. Molecules 2012; 17:9258-73. [PMID: 22858845 PMCID: PMC6268143 DOI: 10.3390/molecules17089258] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2012] [Revised: 07/18/2012] [Accepted: 07/23/2012] [Indexed: 01/18/2023] Open
Abstract
The budding yeast Saccharomyces cerevisiae is a widely used model organism, and yeast genetic methods are powerful tools for discovery of novel functions of genes. Recent advancements in chemical-genetics and chemical-genomics have opened new avenues for development of clinically relevant drug treatments. Systematic mapping of genetic networks by high-throughput chemical-genetic screens have given extensive insight in connections between genetic pathways. Here, I review some of the recent developments in chemical-genetic techniques in budding yeast.
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Affiliation(s)
- Jorrit M Enserink
- Department of Molecular Biology, Institute of Medical Microbiology and Centre for Molecular Biology and Neuroscience, Oslo University Hospital, Sognsvannsveien 20, NO-0027 Oslo, Norway.
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16
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Cdc28 kinase activity regulates the basal transcription machinery at a subset of genes. Proc Natl Acad Sci U S A 2012; 109:10450-5. [PMID: 22689984 DOI: 10.1073/pnas.1200067109] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The cyclin-dependent kinase Cdc28 is the master regulator of the cell cycle in Saccharomyces cerevisiae. Cdc28 initiates the cell cycle by activating cell-cycle-specific transcription factors that switch on a transcriptional program during late G1 phase. Cdc28 also has a cell-cycle-independent, direct function in regulating basal transcription, which does not require its catalytic activity. However, the exact role of Cdc28 in basal transcription remains poorly understood, and a function for its kinase activity has not been fully explored. Here we show that the catalytic activity of Cdc28 is important for basal transcription. Using a chemical-genetic screen for mutants that specifically require the kinase activity of Cdc28 for viability, we identified a plethora of basal transcription factors. In particular, CDC28 interacts genetically with genes encoding kinases that phosphorylate the C-terminal domain of RNA polymerase II, such as KIN28. ChIP followed by high-throughput sequencing (ChIP-seq) revealed that Cdc28 localizes to at least 200 genes, primarily with functions in cellular homeostasis, such as the plasma membrane proton pump PMA1. Transcription of PMA1 peaks early in the cell cycle, even though the promoter sequences of PMA1 (as well as the other Cdc28-enriched ORFs) lack cell-cycle elements, and PMA1 does not recruit Swi4/6-dependent cell-cycle box-binding factor/MluI cell-cycle box binding factor complexes. Finally, we found that recruitment of Cdc28 and Kin28 to PMA1 is mutually dependent and that the activity of both kinases is required for full phosphorylation of C-terminal domain-Ser5, for efficient transcription, and for mRNA capping. Our results reveal a mechanism of cell-cycle-dependent regulation of basal transcription.
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Similar temporal and spatial recruitment of native 19S and 20S proteasome subunits to transcriptionally active chromatin. Proc Natl Acad Sci U S A 2012; 109:6060-5. [PMID: 22474342 DOI: 10.1073/pnas.1200854109] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
It has recently become clear that components of the proteasome are recruited to sites of gene transcription. Prevailing evidence suggests that the transcriptionally relevant form of the proteasome is a subcomplex of 19S base proteins, which functions as an ATP-dependent chaperone that influences transcriptional processes. Despite this notion, compelling evidence for a transcription-dedicated 19S base complex is lacking, and 20S proteasome subunits have been shown to associate with chromatin in some contexts. To gain insight into the form of the proteasome that is recruited to chromatin, we assembled a panel of highly specific antibodies that recognize native yeast proteasome subunits in chromatin immunoprecipitation assays. Using these reagents, we show that components from the three major subassemblies of the proteasome--19S lid, 19S base, and 20S core--associate with the activated GAL10 gene in yeast in a virtually indistinguishable manner. We find that proteasome subunits Rpt1, Rpt4, Rpn8, Rpn12, Pre6, and Pre10 are recruited to GAL10 rapidly upon galactose induction. These subunits associate with the entire transcribed portion of GAL10, display near-identical patterns of distribution, and dissociate from chromatin rapidly once transcription is shut down. We also find that proteasome subunits are enriched at telomeres and at genes transcribed by RNA polymerase III. Our data suggest that the transcriptionally relevant form of the proteasome is the canonical 26S complex.
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18
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The secret life of kinases: functions beyond catalysis. Cell Commun Signal 2011; 9:23. [PMID: 22035226 PMCID: PMC3215182 DOI: 10.1186/1478-811x-9-23] [Citation(s) in RCA: 133] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2011] [Accepted: 10/28/2011] [Indexed: 02/07/2023] Open
Abstract
Protein phosphorylation participates in the regulation of all fundamental biological processes, and protein kinases have been intensively studied. However, while the focus was on catalytic activities, accumulating evidence suggests that non-catalytic properties of protein kinases are essential, and in some cases even sufficient for their functions. These non-catalytic functions include the scaffolding of protein complexes, the competition for protein interactions, allosteric effects on other enzymes, subcellular targeting, and DNA binding. This rich repertoire often is used to coordinate phosphorylation events and enhance the specificity of substrate phosphorylation, but also can adopt functions that do not rely on kinase activity. Here, we discuss such kinase independent functions of protein and lipid kinases focussing on kinases that play a role in the regulation of cell proliferation, differentiation, apoptosis, and motility.
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Lee EK, Kim DG, Kim JS, Yoon Y. Cell-Cycle Regulator Cks1 Promotes Hepatocellular Carcinoma by Supporting NF-κB–Dependent Expression of Interleukin-8. Cancer Res 2011; 71:6827-35. [DOI: 10.1158/0008-5472.can-10-4356] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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20
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21
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SCFCdc4 enables mating type switching in yeast by cyclin-dependent kinase-mediated elimination of the Ash1 transcriptional repressor. Mol Cell Biol 2010; 31:584-98. [PMID: 21098119 DOI: 10.1128/mcb.00845-10] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In the budding yeast Saccharomyces cerevisiae, mother cells switch mating types between a and α forms, whereas daughter cells do not. This developmental asymmetry arises because the expression of the HO endonuclease, which initiates the interconversion of a and α mating type cassettes, is extinguished by the daughter-specific Ash1 transcriptional repressor. When daughters become mothers in the subsequent cell cycle, Ash1 must be eliminated to enable a new developmental state. Here, we report that the ubiquitin ligase SCF(Cdc4) mediates the phosphorylation-dependent elimination of Ash1. The inactivation of SCF(Cdc4) stabilizes Ash1 in vivo, and consistently, Ash1 binds to and is ubiquitinated by SCF(Cdc4) in a phosphorylation-dependent manner in vitro. The mutation of a critical in vivo cyclin-dependent kinase (CDK) phosphorylation site (Thr290) on Ash1 reduces its ubiquitination and rate of degradation in vivo and decreases the frequency of mating type switching. Ash1 associates with active Cdc28 kinase in vivo and is targeted to SCF(Cdc4) in a Cdc28-dependent fashion in vivo and in vitro. Ash1 recognition by Cdc4 appears to be mediated by at least three phosphorylation sites that form two redundant diphosphorylated degrons. The phosphorylation-dependent elimination of Ash1 by the ubiquitin-proteasome system thus underpins developmental asymmetry in budding yeast.
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22
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Cks1, Cdk1, and the 19S proteasome collaborate to regulate gene induction-dependent nucleosome eviction in yeast. Mol Cell Biol 2010; 30:5284-94. [PMID: 20855529 DOI: 10.1128/mcb.00952-10] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Cks1, Cdk1 (Cdc28), and the proteasome are required for efficient transcriptional induction of GAL1 and other genes in Saccharomyces cerevisiae. We show here that one function of these proteins is to reduce nucleosome density on chromatin in a gene induction-specific manner. The transcriptional requirement for Cks1 can be bypassed if nucleosome density is reduced by an alternative pathway, indicating that this is the primary function of Cks1 in the context of gene induction. We further show that Cks1, Cdk1, and the 19S subunit of the proteasome are recruited to chromatin by binding directly to the histone H4 amino-terminal tail. However, this activity of the proteasome does not require the protease activity associated with the 20S subunit. These data suggest a model where binding of a complex consisting of Cks1, Cdk1, and the 19S proteasome to histone H4 leads to removal of nucleosomes via a nonproteolytic activity of the proteasome.
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Abstract
Cyclin-dependent kinase-associated protein 1 (Cks1) is involved in the control of the transcription of a subset of genes in addition to its role in controlling the cell cycle in the budding yeast Saccharomyces cerevisiae. By directly ligating Cks1 onto a GAL1 promoter-driven reporter, we demonstrated that Cks1 acts as a transcription activator. Using this method, we dissected the downstream events from Cks1 recruitment at the promoter. We showed that subsequent to promoter binding, Cdc28 binding is required to modulate the level of gene expression. The ubiquitin-binding domain of Cks1 is essential for implementing downstream transcription events, which appears to recruit the proteasome via ubiquitylated proteasome subunits. We propose that the selective ability of Cks1 to bind ubiquitin allows this small molecule the flexibility to bind large protein complexes with specificity and that this may represent a novel mechanism of regulating transcriptional activation.
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24
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Old JB, Kratzat S, Hoellein A, Graf S, Nilsson JA, Nilsson L, Nakayama KI, Peschel C, Cleveland JL, Keller UB. Skp2 directs Myc-mediated suppression of p27Kip1 yet has modest effects on Myc-driven lymphomagenesis. Mol Cancer Res 2010; 8:353-62. [PMID: 20197382 DOI: 10.1158/1541-7786.mcr-09-0232] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The universal cyclin-dependent kinase inhibitor p27(Kip1) functions as a tumor suppressor, and reduced levels of p27(Kip1) connote poor prognosis in several human malignancies. p27(Kip1) levels are predominately regulated by ubiquitin-mediated turnover of the protein, which is marked for destruction by the E3 ubiquitin ligase SCF(Skp2) complex following its phosphorylation by the cyclin E-cyclin-dependent kinase 2 complex. Binding of phospho-p27(Kip1) is directed by the Skp2 F-box protein, and this is greatly augmented by its allosteric regulator Cks1. We have established that programmed expression of c-Myc in the B cells of Emu-Myc transgenic mice triggers p27(Kip1) destruction by inducing Cks1, that this response controls Myc-driven proliferation, and that loss of Cks1 markedly delays Myc-induced lymphomagenesis and cancels the dissemination of these tumors. Here, we report that elevated levels of Skp2 are a characteristic of Emu-Myc lymphomas and of human Burkitt lymphoma that bear MYC/Immunoglobulin chromosomal translocations. As expected, Myc-mediated suppression of p27(Kip1) was abolished in Skp2-null Emu-Myc B cells. However, the effect of Skp2 loss on Myc-driven proliferation and lymphomagenesis was surprisingly modest compared with the effects of Cks1 loss. Collectively, these findings suggest that Cks1 targets, in addition to p27(Kip1), are critical for Myc-driven proliferation and tumorigenesis.
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Affiliation(s)
- Jennifer B Old
- Department of Biochemistry, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
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25
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Boruc J, Mylle E, Duda M, De Clercq R, Rombauts S, Geelen D, Hilson P, Inzé D, Van Damme D, Russinova E. Systematic localization of the Arabidopsis core cell cycle proteins reveals novel cell division complexes. PLANT PHYSIOLOGY 2010; 152:553-65. [PMID: 20018602 PMCID: PMC2815867 DOI: 10.1104/pp.109.148643] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2009] [Accepted: 12/08/2009] [Indexed: 05/18/2023]
Abstract
Cell division depends on the correct localization of the cyclin-dependent kinases that are regulated by phosphorylation, cyclin proteolysis, and protein-protein interactions. Although immunological assays can define cell cycle protein abundance and localization, they are not suitable for detecting the dynamic rearrangements of molecular components during cell division. Here, we applied an in vivo approach to trace the subcellular localization of 60 Arabidopsis (Arabidopsis thaliana) core cell cycle proteins fused to green fluorescent proteins during cell division in tobacco (Nicotiana tabacum) and Arabidopsis. Several cell cycle proteins showed a dynamic association with mitotic structures, such as condensed chromosomes and the preprophase band in both species, suggesting a strong conservation of targeting mechanisms. Furthermore, colocalized proteins were shown to bind in vivo, strengthening their localization-function connection. Thus, we identified unknown spatiotemporal territories where functional cell cycle protein interactions are most likely to occur.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Eugenia Russinova
- Department of Plant Systems Biology, Flanders Institute for Biotechnology, B–9052 Ghent, Belgium (J.B., E.M., M.D., R.D.C., S.R., P.H., D.I., D.V.D., E.R.); Department of Plant Biotechnology and Genetics, Ghent University, B–9052 Ghent, Belgium (J.B., E.M., M.D., R.D.C., S.R., P.H., D.I., D.V.D., E.R.); and Department of Plant Production, Faculty of Bioscience Engineering, Ghent University, B–9000 Ghent, Belgium (D.G.)
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26
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Haan C, Behrmann I, Haan S. Perspectives for the use of structural information and chemical genetics to develop inhibitors of Janus kinases. J Cell Mol Med 2010; 14:504-27. [PMID: 20132407 PMCID: PMC3823453 DOI: 10.1111/j.1582-4934.2010.01018.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Gain-of-function mutations in the genes encoding Janus kinases have been discovered in various haematologic diseases. Jaks are composed of a FERM domain, an SH2 domain, a pseudokinase domain and a kinase domain, and a complex interplay of the Jak domains is involved in regulation of catalytic activity and association to cytokine receptors. Most activating mutations are found in the pseudokinase domain. Here we present recently discovered mutations in the context of our structural models of the respective domains. We describe two structural hotspots in the pseudokinase domain of Jak2 that seem to be associated either to myeloproliferation or to lymphoblastic leukaemia, pointing at the involvement of distinct signalling complexes in these disease settings. The different domains of Jaks are discussed as potential drug targets. We present currently available inhibitors targeting Jaks and indicate structural differences in the kinase domains of the different Jaks that may be exploited in the development of specific inhibitors. Moreover, we discuss recent chemical genetic approaches which can be applied to Jaks to better understand the role of these kinases in their biological settings and as drug targets.
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Affiliation(s)
- Claude Haan
- Life Sciences Research Unit, University of Luxembourg, 162A, av. de la Faïencerie, 1511 Luxembourg, Luxembourg.
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27
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Radulovic M, Crane E, Crawford M, Godovac-Zimmermann J, Yu VPCC. CKS proteins protect mitochondrial genome integrity by interacting with mitochondrial single-stranded DNA-binding protein. Mol Cell Proteomics 2009; 9:145-52. [PMID: 19786724 DOI: 10.1074/mcp.m900078-mcp200] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cyclin-dependent kinase subunit (CKS) proteins interact with cyclin-dependent kinases (CDKs) with high affinity. Mammalian CKS1 and CKS2 bind CDK1 and CDK2 and partake in the control of cell cycle progression. We identified CKS-interacting proteins by affinity purification followed by mass spectrometry in the human lymphocytic cell line Ramos. Apart from known interactors, such as CDKs, we identified a novel CDK-dependent interaction between CKS proteins and the mitochondrial single-stranded DNA-binding protein (mtSSB). mtSSB bound both CKS1 and CKS2 and underwent CDK-dependent phosphorylation. mtSSB is known to participate in replication of mitochondrial DNA. We demonstrated that mitochondrial morphology and DNA integrity were compromised in cells depleted of both CKS proteins or that had inhibited CDK activity. These features are consistent with the hypothesis of CKS-dependent regulation of mtSSB function and support a direct role of cell cycle proteins in controlling mitochondrial DNA replication.
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Affiliation(s)
- Marko Radulovic
- Eukaryotic Chromatin Dynamics Group, Medical Research Council Clinical Sciences Centre, Imperial College Hammersmith Campus, Du Cane Road, London, UK
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28
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Perry J, Harris RM, Moiani D, Olson AJ, Tainer J. p38alpha MAP kinase C-terminal domain binding pocket characterized by crystallographic and computational analyses. J Mol Biol 2009; 391:1-11. [PMID: 19501598 PMCID: PMC2724755 DOI: 10.1016/j.jmb.2009.06.005] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2009] [Revised: 05/28/2009] [Accepted: 06/01/2009] [Indexed: 01/07/2023]
Abstract
The mitogen-activated protein (MAP) kinase protein family has a critical role in cellular signaling events, with MAP kinase p38alpha acting in inflammatory processes and being an important drug discovery target. MAP kinase drug design efforts have focused on small-molecule inhibitors of the ATP catalytic site, which exhibit dose-limiting adverse effects. Therefore, characterizing other potential sites that bind substrates, inhibitors, or allosteric effectors is of great interest. Here, we present the crystal structure of human p38alpha MAP kinase, which has a lead compound bound both in the active site and in the lipid-binding site of the C-terminal cap. This C-terminal cap is formed from an extension to the kinase fold, unique to the MAP kinase and cyclin-dependent kinase families and glycogen synthase kinase 3. Binding of this lead, 4-[3-(4-fluorophenyl)-1H-pyrazol-4-yl]pyridine, to wild-type p38alpha induces movement of the C-terminal cap region, creating a hydrophobic pocket centered around residue Trp197. Computational analysis of this C-terminal domain pocket indicates notable flexibility for potentially binding different-shaped compounds, including lipids, oxidized arachidonic acid species such as leukotrienes, and small-molecule effectors. Furthermore, our structural results defining the open p38alpha C-lobe pocket provide a detailed framework for the design of novel small molecules with affinities comparable to active-site binders: to bind and potentially modulate the shape and activity of p38alpha in predetermined ways. Moreover, these results and analyses of p38alpha suggest strategies for designing specific binding compounds applicable to other MAP kinases, as well as the cyclin-dependent kinase family and glycogen synthase kinase 3beta that also utilize the C-terminal insert in their interactions.
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Affiliation(s)
- J.J.P. Perry
- Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA 92037, USA.,The School of Biotechnology, Amrita University, Kollam, Kerala 690525, India
| | - R. M Harris
- Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - D. Moiani
- Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - A. J. Olson
- Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - J.A. Tainer
- Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA 92037, USA.,Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.,Correspondence sent to John A. Tainer, , Tel: (858) 784-8119, Fax: (858) 784-2277
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29
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Abstract
Genetic and biochemical studies have provided considerable insight into the multiple functions of cyclin-dependent kinase subunit (cks)1 in cell division cycle. In addition to enhanced substrate targeting by specific ubiquitin ligases SCF(skp2) and APC/C, its direct interaction with proteasome components normalizes multiple cell cycle regulators. Importantly, it also acts as a transcriptional regulator. cks1 overexpression reflects poor prognosis in malignancy thus indicating its possible role in tumour diagnosis and management. The present review compiles the multiple functional roles of cks1 in cell division with specific emphasis on its molecular mechanisms. Its docking functions and the possible downstream proteolytic and transcriptional targets are described. The spatial configuration of cks1-cdk2 complex and the structural organization of cks1-p27-skp2 assembly required for p27 ubiquitination are discussed in detail. In addition to enhanced p27 degradation, the possible other mechanisms which underlie its pathological functions in human cancer progression are also discussed. Though there are apparent gaps in information, the turnover mechanism of cks1 is well addressed and presents opportunity to exploit the target for disease management.
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Affiliation(s)
- Anand Krishnan
- Translational Cancer Research Laboratory, Department of Molecular Medicine, Rajiv Gandhi Centre for Biotechnology, Kerala, India
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30
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Cyclin-dependent kinase-associated proteins Cks1 and Cks2 are essential during early embryogenesis and for cell cycle progression in somatic cells. Mol Cell Biol 2008; 28:5698-709. [PMID: 18625720 DOI: 10.1128/mcb.01833-07] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cks proteins associate with cyclin-dependent kinases and have therefore been assumed to play a direct role in cell cycle regulation. Mammals have two paralogs, Cks1 and Cks2, and individually deleting the gene encoding either in the mouse has previously been shown not to impact viability. In this study we show that simultaneously disrupting CKS1 and CKS2 leads to embryonic lethality, with embryos dying at or before the morula stage after only two to four cell division cycles. RNA interference (RNAi)-mediated silencing of CKS genes in mouse embryonic fibroblasts (MEFs) or HeLa cells causes cessation of proliferation. In MEFs CKS silencing leads to cell cycle arrest in G(2), followed by rereplication and polyploidy. This phenotype can be attributed to impaired transcription of the CCNB1, CCNA2, and CDK1 genes, encoding cyclin B1, cyclin A, and Cdk1, respectively. Restoration of cyclin B1 expression rescues the cell cycle arrest phenotype conferred by RNAi-mediated Cks protein depletion. Consistent with a direct role in transcription, Cks2 is recruited to chromatin in general and to the promoter regions and open reading frames of genes requiring Cks function with a cell cycle periodicity that correlates with their transcription.
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31
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Kanin EI, Kipp RT, Kung C, Slattery M, Viale A, Hahn S, Shokat KM, Ansari AZ. Chemical inhibition of the TFIIH-associated kinase Cdk7/Kin28 does not impair global mRNA synthesis. Proc Natl Acad Sci U S A 2007; 104:5812-7. [PMID: 17392431 PMCID: PMC1851574 DOI: 10.1073/pnas.0611505104] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The process of gene transcription requires the recruitment of a hypophosphorylated form of RNA polymerase II (Pol II) to a gene promoter. The TFIIH-associated kinase Cdk7/Kin28 hyperphosphorylates the promoter-bound polymerase; this event is thought to play a crucial role in transcription initiation and promoter clearance. Studies using temperature-sensitive mutants of Kin28 have provided the most compelling evidence for an essential role of its kinase activity in global mRNA synthesis. In contrast, using a small molecule inhibitor that specifically inhibits Kin28 in vivo, we find that the kinase activity is not essential for global transcription. Unlike the temperature-sensitive alleles, the small-molecule inhibitor does not perturb protein-protein interactions nor does it provoke the disassociation of TFIIH from gene promoters. These results lead us to conclude that other functions of TFIIH, rather than the kinase activity, are critical for global gene transcription.
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Affiliation(s)
| | | | - Charles Kung
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, CA 94143
| | | | - Agnes Viale
- Memorial Sloan–Kettering Cancer Center, New York, NY 10021; and
| | - Steven Hahn
- Fred Hutchinson Cancer Research Center, Seattle, WA 98109
| | - Kevan M. Shokat
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, CA 94143
| | - Aseem Z. Ansari
- *Department of Biochemistry and
- Genome Center of Wisconsin, University of Wisconsin, Madison, WI 53706
- **To whom correspondence should be addressed at:
Department of Biochemistry and The Genome Center of Wisconsin, University of Wisconsin, 433 Babcock Drive, Madison, WI 53706. E-mail:
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32
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Zhan F, Colla S, Wu X, Chen B, Stewart JP, Kuehl WM, Barlogie B, Shaughnessy JD. CKS1B, overexpressed in aggressive disease, regulates multiple myeloma growth and survival through SKP2- and p27Kip1-dependent and -independent mechanisms. Blood 2007; 109:4995-5001. [PMID: 17303695 PMCID: PMC1885527 DOI: 10.1182/blood-2006-07-038703] [Citation(s) in RCA: 117] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Overexpression of CKS1B, a gene mapping within a minimally amplified region between 153 to 154 Mb of chromosome 1q21, is linked to a poor prognosis in multiple myeloma (MM). CKS1B binds to and activates cyclin-dependent kinases and also interacts with SKP2 to promote the ubiquitination and proteasomal degradation of p27(Kip1). Overexpression of CKS1B or SKP2 contributes to increased p27(Kip1) turnover, cell proliferation, and a poor prognosis in many tumor types. Using 4 MM cell lines harboring MAF-, FGFR3/MMSET-, or CCND1-activating translocations, we show that lentiviral delivery of shRNA directed against CKS1B resulted in ablation of CKS1B mRNA and protein with concomitant stabilization of p27(Kip1), cell cycle arrest, and apoptosis. Although shRNA-mediated knockdown of SKP2 and forced expression of a nondegradable form of p27(Kip1) (p27(T187A)) led to cell cycle arrest, apoptosis was modest. Of importance, while knockdown of SKP2 or overexpression of p27(T187A) induced cell cycle arrest in KMS28PE, an MM cell line with biallelic deletion of CDKN1B/p27(Kip1), CKS1B ablation induced strong apoptosis. These data suggest that CKS1B influences myeloma cell growth and survival through SKP2- and p27(Kip1)-dependent and -independent mechanisms and that therapeutic strategies aimed at abolishing CKS1B function may hold promise for the treatment of high-risk disease for which effective therapies are currently lacking.
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Affiliation(s)
- Fenghuang Zhan
- Donna D and Donald M. Lambert Laboratory of Myeloma Genetics at the Myeloma Institute for Research and Therapy, University of Arkansas for Medical Sciences, 4301 W. Markham Street, Little Rock, AR 72205, USA.
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Mourot M, Dufort I, Gravel C, Algriany O, Dieleman S, Sirard MA. The influence of follicle size, FSH-enriched maturation medium, and early cleavage on bovine oocyte maternal mRNA levels. Mol Reprod Dev 2006; 73:1367-79. [PMID: 16894554 DOI: 10.1002/mrd.20585] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Transcription is arrested in the bovine oocyte within the first few hours of in vitro maturation, thus the stored maternal mRNAs accumulated in the oocyte are essential to sustain development until the Maternal-Zygotic Transition. In vivo matured oocytes have superior blastocyst formation rates than in vitro matured oocytes, suggesting that the mRNA content of these oocytes is of higher quality. To determine which transcripts may be associated with developmental competence, a Suppressive Subtractive Hybridization was performed between oocytes collected by ovariectomy at 6 hr post-LH surge and oocytes from slaughterhouse collected after 6 hr of maturation, resulting in a library enriched in these functionally important mRNAs. The clones were spotted onto a cDNA microarray and transcripts potentially associated with developmental competence were hybridized onto these slides. Hybridizations were performed with transcripts up-regulated in oocytes cultured for 6 hr in the presence or absence of rFSH in vitro, and secondly with transcripts up regulated in early-cleaving embryos versus those at the one-cell stage at 36 hr postfertilization. From these hybridizations, 13 candidates were selected. Their functional association with embryonic competence was validated by measuring their relative transcript levels by quantitative real-time PCR in eight different conditions: oocytes cultured with or without rFSH, early--versus late-cleaving embryos, and oocytes from different follicle sizes (1-3, 3-5, 5-8, and >8 mm of diameter). The gene candidates CCNB2, PTTG1, H2A, CKS1, PSMB2, SKIIP, CDC5L, RGS16, and PRDX1 showed a significant quantitative association with competence compared to BMP15, GDF9, CCNB1, and STK6.
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Affiliation(s)
- Marina Mourot
- Département des Sciences Animales, Centre de Recherche en Biologie de la Reproduction, Université Laval, Sainte Foy, Québec, Canada
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Yeong SS, Zhu Y, Smith D, Verma C, Lim WG, Tan BJ, Li QT, Cheung NS, Cai M, Zhu YZ, Zhou SF, Tan SL, Duan W. The last 10 amino acid residues beyond the hydrophobic motif are critical for the catalytic competence and function of protein kinase Calpha. J Biol Chem 2006; 281:30768-81. [PMID: 16895917 DOI: 10.1074/jbc.m511278200] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The segment C-terminal to the hydrophobic motif at the V5 domain of protein kinase C (PKC) is the least conserved both in length and in amino acid identity among all PKC isozymes. By generating serial truncation mutants followed by biochemical and functional analyses, we show here that the very C terminus of PKCalpha is critical in conferring the full catalytic competence to the kinase and for transducing signals in cells. Deletion of one C-terminal amino acid residue caused the loss of approximately 60% of the catalytic activity of the mutant PKCalpha, whereas deletion of 10 C-terminal amino acid residues abrogated the catalytic activity of PKCalpha in immune complex kinase assays. The PKCalpha C-terminal truncation mutants were found to lose their ability to activate mitogen-activated protein kinase, to rescue apoptosis induced by the inhibition of endogenous PKC in COS cells, and to augment melatonin-stimulated neurite outgrowth. Furthermore, molecular dynamics simulations revealed that the deletion of 1 or 10 C-terminal residues results in the deformation of the V5 domain and the ATP-binding pocket, respectively. Finally, PKCalpha immunoprecipitated using an antibody against its C terminus had only marginal catalytic activity compared with that of the PKCalpha immunoprecipitated by an antibody against its N terminus. Therefore, the very C-terminal tail of PKCalpha is a novel determinant of the catalytic activity of PKC and a promising target for selective modulation of PKCalpha function. Molecules that bind preferentially to the very C terminus of distinct PKC isozymes and suppress their catalytic activity may constitute a new class of selective inhibitors of PKC.
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Affiliation(s)
- Sui Sum Yeong
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, 8 Medical Drive, Singapore 117597
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Kholmurodov KT, Kretov DA, Gerasimova AS, Koltovaya NA. Molecular dynamics simulation of the substitution of serine for the conserved glycine in the G-loop in the cdc28-srm yeast mutant using the crystal lattice of human CDK2 kinase. Biophysics (Nagoya-shi) 2006. [DOI: 10.1134/s0006350906040142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Collins GA, Tansey WP. The proteasome: a utility tool for transcription? Curr Opin Genet Dev 2006; 16:197-202. [PMID: 16503126 DOI: 10.1016/j.gde.2006.02.009] [Citation(s) in RCA: 197] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2005] [Accepted: 02/13/2006] [Indexed: 01/15/2023]
Abstract
A growing body of evidence demonstrates that the components of the proteasome are involved directly and mechanistically in the regulation of gene transcription. Proteolytic activities of the proteasome are important for establishing limits for transcription, for promoting the exchange of transcription factors on chromatin, and possibly for facilitating multiple rounds of transcription initiation. Non-proteolytic activities of the proteasome are important for co-activator recruitment, transcriptional elongation, and histone modification. Here, we discuss different ways in which the proteasome can influence transcription, and argue that its unique combination of biological activities makes it ideally suited to act at multiple stages in the transcription process.
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Affiliation(s)
- Galen A Collins
- Cold Spring Harbor Laboratory, Watson School of Biological Sciences, 1 Bungtown Road, Cold Spring Harbor, NY 11724, USA
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Abstract
Ubiquitin-mediated proteolysis is one of the key mechanisms underlying cell cycle control. The removal of barriers posed by accumulation of negative regulators, as well as the clearance of proteins when they are no longer needed or deleterious, are carried out via the ubiquitin-proteasome system. Ubiquitin conjugating enzymes and protein-ubiquitin ligases collaborate to mark proteins destined for degradation by the proteasome by covalent attachment of multi-ubiquitin chains. Most regulated proteolysis during the cell cycle can be attributed to two families of protein-ubiquitin ligases. The anaphase promoting complex/cyclosome (APC/C) is activated during mitosis and G1 where it is responsible for eliminating proteins that impede mitotic progression and that would have deleterious consequences if allowed to accumulate during G1. SCF (Skp1/Culin/F-box protein) protein-ubiquitin ligases ubiquitylate proteins that are marked by phosphorylation at specific sequences known as phosphodegrons. Targeting of proteins for destruction by phosphorylation provides a mechanism for linking cell cycle regulation to internal and external signaling pathways via regulated protein kinase activities.
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Affiliation(s)
- Steven I Reed
- Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA 92037, USA.
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Shirayama M, Soto MC, Ishidate T, Kim S, Nakamura K, Bei Y, van den Heuvel S, Mello CC. The Conserved Kinases CDK-1, GSK-3, KIN-19, and MBK-2 Promote OMA-1 Destruction to Regulate the Oocyte-to-Embryo Transition in C. elegans. Curr Biol 2006; 16:47-55. [PMID: 16343905 DOI: 10.1016/j.cub.2005.11.070] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2005] [Revised: 11/18/2005] [Accepted: 11/23/2005] [Indexed: 11/25/2022]
Abstract
BACKGROUND At the onset of embryogenesis, key developmental regulators called determinants are activated asymmetrically to specify the body axes and tissue layers. In C. elegans, this process is regulated in part by a conserved family of CCCH-type zinc finger proteins that specify the fates of early embryonic cells. The asymmetric localization of these and other determinants is regulated in early embryos through motor-dependent physical translocation as well as selective proteolysis. RESULTS We show here that the CCCH-type zinc finger protein OMA-1 serves as a nexus for signals that regulate the transition from oogenesis to embryogenesis. While OMA-1 promotes oocyte maturation during meiosis, destruction of OMA-1 is needed during the first cell division for the initiation of ZIF-1-dependent proteolysis of cell-fate determinants. Mutations in four conserved protein kinase genes-mbk-2/Dyrk, kin-19/CK1alpha, gsk-3, and cdk-1/CDC2-cause stabilization of OMA-1 protein, and their phenotypes are partially suppressed by an oma-1 loss-of-function mutation. OMA-1 proteolysis also depends on Cyclin B3 and on a ZIF-1-independent CUL-2-based E3 ubiquitin ligase complex, as well as the CUL-2-interacting protein ZYG-11 and the Skp1-related proteins SKR-1 and SKR-2. CONCLUSIONS Our findings suggest that a CDK1/Cyclin B3-dependent activity links OMA-1 proteolysis to completion of the first cell cycle and support a model in which OMA-1 functions to prevent the premature activation of cell-fate determinants until after they are asymmetrically partitioned during the first mitosis.
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Affiliation(s)
- Masaki Shirayama
- Program in Molecular Medicine, University of Massachusetts Medical School, 373 Plantation Street, Worcester, Massachusetts 01605
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Fan QW, Weiss WA. Chemical genetic approaches to the development of cancer therapeutics. Curr Opin Genet Dev 2005; 16:85-91. [PMID: 16359858 DOI: 10.1016/j.gde.2005.12.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2005] [Accepted: 12/02/2005] [Indexed: 12/30/2022]
Abstract
Dysregulation of kinase-based signal transduction networks contributes to multiple aspects of malignancy. Chemical genetic approaches interrogate perturbed signaling in the immediate context of small molecule inhibitor treatment. In recent years, such approaches have identified new kinase targets, clarified the impact of poly-specific inhibition using agents for which at least one primary target is known, and have identified targets for which combinatorial inhibition leads to improved efficacy. Elucidation of the mechanisms through which specific small molecule drug-like agents impact crucial cancer pathways should yield important and clinically translatable insights into the use of similar agents in patients.
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MESH Headings
- Amino Acid Sequence
- Animals
- Genes, abl
- Humans
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/drug therapy
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/etiology
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/genetics
- Models, Biological
- Neoplasms/drug therapy
- Neoplasms/etiology
- Neoplasms/genetics
- Protein Kinases/genetics
- Sequence Homology, Amino Acid
- Signal Transduction/drug effects
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Affiliation(s)
- Qi-Wen Fan
- Department of Neurology, 533 Parnassus Avenue, San Francisco, CA 94143, USA
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Lee D, Ezhkova E, Li B, Pattenden SG, Tansey WP, Workman JL. The Proteasome Regulatory Particle Alters the SAGA Coactivator to Enhance Its Interactions with Transcriptional Activators. Cell 2005; 123:423-36. [PMID: 16269334 DOI: 10.1016/j.cell.2005.08.015] [Citation(s) in RCA: 142] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2005] [Revised: 06/13/2005] [Accepted: 08/03/2005] [Indexed: 11/28/2022]
Abstract
Promoter recruitment of the Saccharomyces cerevisiae SAGA histone acetyltransferase complex is required for RNA polymerase II-dependent transcription of several genes. SAGA is targeted to promoters through interactions with sequence-specific DNA binding transcriptional activators and facilitates preinitiation-complex assembly and transcription. Here, we show that the 19S proteasome regulatory particle (19S RP) alters SAGA to stimulate its interaction with transcriptional activators. The ATPase components of the 19S RP are required for stimulation of SAGA/activator interactions and enhance SAGA recruitment to promoters. Proteasomal ATPases genetically interact with SAGA, and their inhibition reduces global histone H3 acetylation levels and SAGA recruitment to target promoters in vivo. These results indicate that the 19S RP modulates SAGA complex using its ATPase components, thereby facilitating subsequent transcription events at promoters.
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Affiliation(s)
- Daeyoup Lee
- Stowers Institute for Medical Research, 1000 East 50th Street, Kansas City, Missouri 64110, USA
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Knight ZA, Shokat KM. Features of Selective Kinase Inhibitors. ACTA ACUST UNITED AC 2005; 12:621-37. [PMID: 15975507 DOI: 10.1016/j.chembiol.2005.04.011] [Citation(s) in RCA: 492] [Impact Index Per Article: 25.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2005] [Revised: 04/12/2005] [Accepted: 04/13/2005] [Indexed: 11/19/2022]
Abstract
Small-molecule inhibitors of protein and lipid kinases have emerged as indispensable tools for studying signal transduction. Despite the widespread use of these reagents, there is little consensus about the biochemical criteria that define their potency and selectivity in cells. We discuss some of the features that determine the cellular activity of kinase inhibitors and propose a framework for interpreting inhibitor selectivity.
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Affiliation(s)
- Zachary A Knight
- Program in Chemistry and Chemical Biology, University of California-San Francisco, San Francisco, CA 94143, USA
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