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Zabihi M, Lotfi R, Yousefi AM, Bashash D. Cyclins and cyclin-dependent kinases: from biology to tumorigenesis and therapeutic opportunities. J Cancer Res Clin Oncol 2023; 149:1585-1606. [PMID: 35781526 DOI: 10.1007/s00432-022-04135-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Accepted: 06/13/2022] [Indexed: 12/20/2022]
Abstract
The discussion on cell proliferation cannot be continued without taking a look at the cell cycle regulatory machinery. Cyclin-dependent kinases (CDKs), cyclins, and CDK inhibitors (CKIs) are valuable members of this system and their equilibrium guarantees the proper progression of the cell cycle. As expected, any dysregulation in the expression or function of these components can provide a platform for excessive cell proliferation leading to tumorigenesis. The high frequency of CDK abnormalities in human cancers, together with their druggable structure has raised the possibility that perhaps designing a series of inhibitors targeting CDKs might be advantageous for restricting the survival of tumor cells; however, their application has faced a serious concern, since these groups of serine-threonine kinases possess non-canonical functions as well. In the present review, we aimed to take a look at the biology of CDKs and then magnify their contribution to tumorigenesis. Then, by arguing the bright and dark aspects of CDK inhibition in the treatment of human cancers, we intend to reach a consensus on the application of these inhibitors in clinical settings.
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Affiliation(s)
- Mitra Zabihi
- Department of Hematology and Blood Banking, School of Allied Medical Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Ramin Lotfi
- Clinical Research Development Center, Tohid Hospital, Kurdistan University of Medical Sciences, Sanandaj, Iran
| | - Amir-Mohammad Yousefi
- Department of Hematology and Blood Banking, School of Allied Medical Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Davood Bashash
- Department of Hematology and Blood Banking, School of Allied Medical Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
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Bai J, Guo D, Li J, Wang H, Wang C, Liu Z, Guo X, Wang Y, Xu B. The role of AccCDK20 and AccCDKN1 from Apis cerana cerana in development and response to pesticide and heavy metal toxicity. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2023; 190:105333. [PMID: 36740341 DOI: 10.1016/j.pestbp.2022.105333] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 12/16/2022] [Accepted: 12/20/2022] [Indexed: 06/18/2023]
Abstract
Apis cerana cerana is a native bee species in China and plays a key role in agricultural production and ecological balance. However, the growth and development of Apis cerana cerana has not been smooth, and pesticide and heavy metal stress are key factors that have forced a dramatic decline in population size. This study was performed with the objective of investigating the role of AccCDK20 and AccCDKN1 in honey bee resistance to pesticide and heavy metal stress. RT-qPCR analysis revealed that AccCDK20 transcript levels were highest in brown-eyed pupae and AccCDKN1 transcript levels were highest in 1-day-old worker bees. In different tissues and body parts of adult bees, AccCDK20 transcript levels were highest in the head, and AccCDKN1 transcript levels were highest in the thorax. It was further observed that environmental stress can affect the transcript levels of the AccCDK20 and AccCDKN1 genes. Silencing of the AccCDK20 and AccCDKN1 genes resulted in altered activities of antioxidant-related genes and antioxidant-related enzymes. AccCDK20 and AccCDKN1 transcript levels were upregulated under glyphosate stress, and silencing of the genes resulted in reduced resistance to glyphosate and greatly increased mortality in Apis cerana cerana. In addition, gene function was verified by in vitro repression assays. Overexpression of the AccCDK20 and AccCDKN1 proteins in E. coli cells increased the resistance to ROS damage induced by CHP. In conclusion, AccCDK20 and AccCDKN1 play an indispensable role in honey bee resistance to pesticide and heavy metal stress.
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Affiliation(s)
- Jinhao Bai
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Taian, Shandong 271018, PR China
| | - Dezheng Guo
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Taian, Shandong 271018, PR China
| | - Jing Li
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Taian, Shandong 271018, PR China
| | - Hongfang Wang
- College of Animal Science and Technology, Shandong Agricultural University, Taian, Shandong 271018, PR China
| | - Chen Wang
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Taian, Shandong 271018, PR China
| | - Zhenguo Liu
- College of Animal Science and Technology, Shandong Agricultural University, Taian, Shandong 271018, PR China
| | - Xingqi Guo
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Taian, Shandong 271018, PR China
| | - Ying Wang
- College of Animal Science and Technology, Shandong Agricultural University, Taian, Shandong 271018, PR China.
| | - Baohua Xu
- College of Animal Science and Technology, Shandong Agricultural University, Taian, Shandong 271018, PR China.
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The Role of Cell Cycle Regulators in Cell Survival-Dual Functions of Cyclin-Dependent Kinase 20 and p21 Cip1/Waf1. Int J Mol Sci 2020; 21:ijms21228504. [PMID: 33198081 PMCID: PMC7698114 DOI: 10.3390/ijms21228504] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Accepted: 11/06/2020] [Indexed: 12/11/2022] Open
Abstract
The mammalian cell cycle is important in controlling normal cell proliferation and the development of various diseases. Cell cycle checkpoints are well regulated by both activators and inhibitors to avoid cell growth disorder and cancerogenesis. Cyclin dependent kinase 20 (CDK20) and p21Cip1/Waf1 are widely recognized as key regulators of cell cycle checkpoints controlling cell proliferation/growth and involving in developing multiple cancers. Emerging evidence demonstrates that these two cell cycle regulators also play an essential role in promoting cell survival independent of the cell cycle, particularly in those cells with a limited capability of proliferation, such as cardiomyocytes. These findings bring new insights into understanding cytoprotection in these tissues. Here, we summarize the new progress of the studies on these two molecules in regulating cell cycle/growth, and their new roles in cell survival by inhibiting various cell death mechanisms. We also outline their potential implications in cancerogenesis and protection in heart diseases. This information renews the knowledge in molecular natures and cellular functions of these regulators, leading to a better understanding of the pathogenesis of the associated diseases and the discovery of new therapeutic strategies.
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Lemonnier T, Dupré A, Jessus C. The G2-to-M transition from a phosphatase perspective: a new vision of the meiotic division. Cell Div 2020; 15:9. [PMID: 32508972 PMCID: PMC7249327 DOI: 10.1186/s13008-020-00065-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Accepted: 05/12/2020] [Indexed: 12/15/2022] Open
Abstract
Cell division is orchestrated by the phosphorylation and dephosphorylation of thousands of proteins. These post-translational modifications underlie the molecular cascades converging to the activation of the universal mitotic kinase, Cdk1, and entry into cell division. They also govern the structural events that sustain the mechanics of cell division. While the role of protein kinases in mitosis has been well documented by decades of investigations, little was known regarding the control of protein phosphatases until the recent years. However, the regulation of phosphatase activities is as essential as kinases in controlling the activation of Cdk1 to enter M-phase. The regulation and the function of phosphatases result from post-translational modifications but also from the combinatorial association between conserved catalytic subunits and regulatory subunits that drive their substrate specificity, their cellular localization and their activity. It now appears that sequential dephosphorylations orchestrated by a network of phosphatase activities trigger Cdk1 activation and then order the structural events necessary for the timely execution of cell division. This review discusses a series of recent works describing the important roles played by protein phosphatases for the proper regulation of meiotic division. Many breakthroughs in the field of cell cycle research came from studies on oocyte meiotic divisions. Indeed, the meiotic division shares most of the molecular regulators with mitosis. The natural arrests of oocytes in G2 and in M-phase, the giant size of these cells, the variety of model species allowing either biochemical or imaging as well as genetics approaches explain why the process of meiosis has served as an historical model to decipher signalling pathways involved in the G2-to-M transition. The review especially highlights how the phosphatase PP2A-B55δ critically orchestrates the timing of meiosis resumption in amphibian oocytes. By opposing the kinase PKA, PP2A-B55δ controls the release of the G2 arrest through the dephosphorylation of their substrate, Arpp19. Few hours later, the inhibition of PP2A-B55δ by Arpp19 releases its opposing kinase, Cdk1, and triggers M-phase. In coordination with a variety of phosphatases and kinases, the PP2A-B55δ/Arpp19 duo therefore emerges as the key effector of the G2-to-M transition.
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Affiliation(s)
- Tom Lemonnier
- Laboratoire de Biologie du Développement-Institut de Biologie Paris Seine, LBD-IBPS, Sorbonne Université, CNRS, 75005 Paris, France
| | - Aude Dupré
- Laboratoire de Biologie du Développement-Institut de Biologie Paris Seine, LBD-IBPS, Sorbonne Université, CNRS, 75005 Paris, France
| | - Catherine Jessus
- Laboratoire de Biologie du Développement-Institut de Biologie Paris Seine, LBD-IBPS, Sorbonne Université, CNRS, 75005 Paris, France
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Suppression of Angiogenesis by Targeting Cyclin-Dependent Kinase 7 in Human Umbilical Vein Endothelial Cells and Renal Cell Carcinoma: An In Vitro and In Vivo Study. Cells 2019; 8:cells8111469. [PMID: 31752390 PMCID: PMC6912535 DOI: 10.3390/cells8111469] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2019] [Revised: 10/28/2019] [Accepted: 11/14/2019] [Indexed: 12/11/2022] Open
Abstract
Cancer cells rely on aberrant transcription for growth and survival. Cyclin-dependent kinases (CDKs) play critical roles in regulating gene transcription by modulating the activity of RNA polymerase II (RNAPII). THZ1, a selective covalent inhibitor of CDK7, has antitumor effects in several human cancers. In this study, we investigated the role and therapeutic potential of CDK7 in regulating the angiogenic activity of endothelial cells and human renal cell carcinoma (RCC). Our results revealed that vascular endothelial growth factor (VEGF), a critical activator of angiogenesis, upregulated the expression of CDK7 and RNAPII, and the phosphorylation of RNAPII at serine 5 and 7 in human umbilical vein endothelial cells (HUVECs), indicating the transcriptional activity of CDK7 may be involved in VEGF-activated angiogenic activity of endothelium. Furthermore, through suppressing CDK7 activity, THZ1 suppressed VEGF-activated proliferation and migration, as well as enhanced apoptosis of HUVECs. Moreover, THZ1 inhibited VEGF-activated capillary tube formation and CDK7 knockdown consistently diminished tube formation in HUVECs. Additionally, THZ1 reduced VEGF expression in human RCC cells (786-O and Caki-2), and THZ1 treatment inhibited tumor growth, vascularity, and angiogenic marker (CD31) expression in RCC xenografts. Our results demonstrated that CDK7-mediated transcription was involved in the angiogenic activity of endothelium and human RCC. THZ1 suppressed VEGF-mediated VEGFR2 downstream activation of angiogenesis, providing a new perspective for antitumor therapy in RCC patients.
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Troadec S, Blairvacq M, Oumata N, Galons H, Meijer L, Berthou C. Antitumoral effects of cyclin-dependent kinases inhibitors CR8 and MR4 on chronic myeloid leukemia cell lines. J Biomed Sci 2015; 22:57. [PMID: 26184865 PMCID: PMC4504225 DOI: 10.1186/s12929-015-0163-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Accepted: 07/02/2015] [Indexed: 12/14/2022] Open
Abstract
Background Although Imatinib mesylate has revolutionized the treatment of chronic myeloid leukemia, some patients develop resistance with progression of leukemia. Alternative or additional targeting of signalling pathways deregulated in Bcr-Abl-driven chronic myeloid leukemia may provide a feasible option for improving clinical response and overcoming resistance. Results In this study, we investigate ability of CR8 isomers (R-CR8 and S-CR8) and MR4, three derivatives of the cyclin-dependent kinases (CDKs) inhibitor Roscovitine, to exert anti-leukemic activities against chronic myeloid leukemia in vitro and then, we decipher their mechanisms of action. We show that these CDKs inhibitors are potent inducers of growth arrest and apoptosis of both Imatinib-sensitive and –resistant chronic myeloid leukemia cell lines. CR8 and MR4 induce dose-dependent apoptosis through mitochondrial pathway and further caspases 8/10 and 9 activation via down-regulation of short-lived survival and anti-apoptotic factors Mcl-1, XIAP and survivin which are strongly implicated in survival of Bcr-Abl transformed cells. Conclusions These results suggest that CDK inhibitors may constitute a complementary approach to treat chronic myeloid leukemia. Electronic supplementary material The online version of this article (doi:10.1186/s12929-015-0163-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Samuel Troadec
- Laboratoire de Thérapie Cellulaire et Immunobiologie du Cancer, Université de Bretagne Occidentale, CHRU Morvan, 5 avenue Foch, 29609, Brest Cedex, France. .,Current address: Institut Universitaire Technologique, Département de Génie Biologique, Brest, France.
| | - Mélina Blairvacq
- "Protein Phosphorylation and Human Diseases" Group, CNRS, USR3151, Station Biologique, Roscoff, France.
| | - Nassima Oumata
- ManRos Therapeutics, Hôtel de Recherche, Centre de Perharidy, Roscoff, France.
| | - Hervé Galons
- Unité de Technologies Chimiques et Biologiques pour la Santé, Université Paris Descartes UMR-S 1022 Inserm, 4 avenue de l'Observatoire, Paris, France.
| | - Laurent Meijer
- ManRos Therapeutics, Hôtel de Recherche, Centre de Perharidy, Roscoff, France.
| | - Christian Berthou
- Laboratoire de Thérapie Cellulaire et Immunobiologie du Cancer, Université de Bretagne Occidentale, CHRU Morvan, 5 avenue Foch, 29609, Brest Cedex, France.
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Tao L, Fu R, Wang X, Yao J, Zhou Y, Dai Q, Li Z, Lu N, Wang W. LL-202, a newly synthesized flavonoid, inhibits tumor growth via inducing G2/M phase arrest and cell apoptosis in MCF-7 human breast cancer cells in vitro and in vivo. Toxicol Lett 2014; 228:1-12. [DOI: 10.1016/j.toxlet.2014.04.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Revised: 03/31/2014] [Accepted: 04/03/2014] [Indexed: 10/25/2022]
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Bisteau X, Paternot S, Colleoni B, Ecker K, Coulonval K, De Groote P, Declercq W, Hengst L, Roger PP. CDK4 T172 phosphorylation is central in a CDK7-dependent bidirectional CDK4/CDK2 interplay mediated by p21 phosphorylation at the restriction point. PLoS Genet 2013; 9:e1003546. [PMID: 23737759 PMCID: PMC3667761 DOI: 10.1371/journal.pgen.1003546] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2012] [Accepted: 04/22/2013] [Indexed: 01/24/2023] Open
Abstract
Cell cycle progression, including genome duplication, is orchestrated by cyclin-dependent kinases (CDKs). CDK activation depends on phosphorylation of their T-loop by a CDK–activating kinase (CAK). In animals, the only known CAK for CDK2 and CDK1 is cyclin H-CDK7, which is constitutively active. Therefore, the critical activation step is dephosphorylation of inhibitory sites by Cdc25 phosphatases rather than unrestricted T-loop phosphorylation. Homologous CDK4 and CDK6 bound to cyclins D are master integrators of mitogenic/oncogenic signaling cascades by initiating the inactivation of the central oncosuppressor pRb and cell cycle commitment at the restriction point. Unlike the situation in CDK1 and CDK2 cyclin complexes, and in contrast to the weak but constitutive T177 phosphorylation of CDK6, we have identified the T-loop phosphorylation at T172 as the highly regulated step determining CDK4 activity. Whether both CDK4 and CDK6 phosphorylations are catalyzed by CDK7 remains unclear. To answer this question, we took a chemical-genetics approach by using analogue-sensitive CDK7(as/as) mutant HCT116 cells, in which CDK7 can be specifically inhibited by bulky adenine analogs. Intriguingly, CDK7 inhibition prevented activating phosphorylations of CDK4/6, but for CDK4 this was at least partly dependent on its binding to p21cip1. In response to CDK7 inhibition, p21-binding to CDK4 increased concomitantly with disappearance of the most abundant phosphorylation of p21, which we localized at S130 and found to be catalyzed by both CDK4 and CDK2. The S130A mutation of p21 prevented the activating CDK4 phosphorylation, and inhibition of CDK4/6 and CDK2 impaired phosphorylations of both p21 and p21-bound CDK4. Therefore, specific CDK7 inhibition revealed the following: a crucial but partly indirect CDK7 involvement in phosphorylation/activation of CDK4 and CDK6; existence of CDK4-activating kinase(s) other than CDK7; and novel CDK7-dependent positive feedbacks mediated by p21 phosphorylation by CDK4 and CDK2 to sustain CDK4 activation, pRb inactivation, and restriction point passage. In the cell cycle, duplication of all the cellular components and subsequent cell division are governed by a family of protein kinases associated with cyclins (CDKs). Related CDK4 and CDK6 bound to cyclins D are the first CDKs to be activated in response to cell proliferation signals. They thus play a central role in the cell multiplication decision, especially in most cancer cells in which CDK4 activity is highly deregulated. We have identified the activating T172 phosphorylation instead of cyclin D expression as the highly regulated step determining CDK4 activation. This finding contrasts with the prevalent view that the only identified metazoan CDK-activating kinase, CDK7, is constitutively active. By using human cells genetically engineered for specific chemical inhibition of CDK7, we found that CDK7 activity was indeed required for CDK4 activation. However, this dependence was conditioned by CDK4 binding to the CDK inhibitory protein p21, which increased in response to CDK7 inhibition. Further investigation revealed that CDK7 inhibition affects a major phosphorylation of p21, which we found to be required for CDK4 activation and performed by CDK4 itself and CDK2. Thus, depending on CDK7 activity, CDK4 and CDK2 facilitate CDK4 activation, generating novel positive feedbacks involved in the cell cycle decision.
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Affiliation(s)
- Xavier Bisteau
- WELBIO and Institute of Interdisciplinary Research (IRIBHM), Université Libre de Bruxelles, Brussels, Belgium
| | - Sabine Paternot
- WELBIO and Institute of Interdisciplinary Research (IRIBHM), Université Libre de Bruxelles, Brussels, Belgium
| | - Bianca Colleoni
- WELBIO and Institute of Interdisciplinary Research (IRIBHM), Université Libre de Bruxelles, Brussels, Belgium
| | - Karin Ecker
- Division of Medical Biochemistry, Biocenter, Innsbruck Medical University, Innsbruck, Austria
| | - Katia Coulonval
- WELBIO and Institute of Interdisciplinary Research (IRIBHM), Université Libre de Bruxelles, Brussels, Belgium
| | - Philippe De Groote
- Department for Molecular Biomedical Research, VIB, and Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - Wim Declercq
- Department for Molecular Biomedical Research, VIB, and Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - Ludger Hengst
- Division of Medical Biochemistry, Biocenter, Innsbruck Medical University, Innsbruck, Austria
| | - Pierre P. Roger
- WELBIO and Institute of Interdisciplinary Research (IRIBHM), Université Libre de Bruxelles, Brussels, Belgium
- * E-mail:
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Yap TA, Molife LR, Blagden SP, de Bono S. Targeting cell cycle kinases and kinesins in anticancer drug development. Expert Opin Drug Discov 2013; 2:539-60. [PMID: 23484760 DOI: 10.1517/17460441.2.4.539] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The cell cycle is regulated by kinases such as the cyclin-dependent kinases (CDKs) and non-CDKs, which include Aurora and polo-like kinases, as well as checkpoint proteins. Mitotic kinesins are involved in the establishment of the mitotic spindle formation and function, and also play a role in cell cycle control. The disruption of the cell cycle is a hallmark of malignancy. Genetic or epigenetic events result in the upregulation of these kinases and mitotic kinesins in a myriad of tumour types, suggesting that their inhibition could result in preferential targeting of malignant cells. Such findings make the development of these inhibitors a rational and attractive new area for cancer therapeutics. Although challenges of potency and non-specificity have hampered their progress through the clinic, several novel compounds are presently in various phases of clinical trial evaluation.
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Affiliation(s)
- Timothy A Yap
- Drug Development Unit, The Royal Marsden NHS Foundation Trust, Downs Road, Sutton, Surrey, SM2 5PT, UK.
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TIAN YE, WAN HAN, TAN GUANG. Cell cycle-related kinase in carcinogenesis. Oncol Lett 2012; 4:601-606. [PMID: 23205069 PMCID: PMC3506610 DOI: 10.3892/ol.2012.828] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2012] [Accepted: 07/24/2012] [Indexed: 12/16/2022] Open
Abstract
Cell cycle-related kinase (CCRK) is a novel protein kinase homologous to both cyclin-dependent kinase 7 (Cdk7) and Cak1p groups of CDK-activating kinase (CAK). CCRK activates Cdk2, which controls the cell-cycle progression by phosphorylating a threonine residue conserved in Cdk2. Previous studies have indicated that the CCRK protein levels were elevated by more than 1.5-fold in tumor tissue, and that the overexpression of CCRK is associated with poor prognosis of the patients. Moreover, recent studies have shown that CCRK is involved in the Wnt signaling pathway associated with the genesis and evolution of cancer. This review aims to systematically present the information currently available on CCRK obtained from in vitro and in vivo studies and highlight its significance to tumorigenesis.
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Affiliation(s)
- YE TIAN
- Department of General Surgery, First Affiliated Hospital, Dalian Medical University, Dalian, Liaoning 116011,
P.R. China
| | - HAN WAN
- Department of General Surgery, First Affiliated Hospital, Dalian Medical University, Dalian, Liaoning 116011,
P.R. China
| | - GUANG TAN
- Department of General Surgery, First Affiliated Hospital, Dalian Medical University, Dalian, Liaoning 116011,
P.R. China
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11
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Willis RE. Human gene control by vital oncogenes: revisiting a theoretical model and its implications for targeted cancer therapy. Int J Mol Sci 2011; 13:316-35. [PMID: 22312254 PMCID: PMC3269688 DOI: 10.3390/ijms13010316] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2011] [Revised: 12/18/2011] [Accepted: 12/20/2011] [Indexed: 12/31/2022] Open
Abstract
An important assumption of our current understanding of the mechanisms of carcinogenesis has been the belief that clarification of the cancer process would inevitably reveal some of the crucial mechanisms of normal human gene regulation. Since the momentous work of Bishop and Varmus, both the molecular and the biochemical processes underlying the events in the development of cancer have become increasingly clear. The identification of cellular signaling pathways and the role of protein kinases in the events leading to gene activation have been critical to our understanding not only of normal cellular gene control mechanisms, but also have clarified some of the important molecular and biochemical events occurring within a cancer cell. We now know that oncogenes are dysfunctional proto-oncogenes and that dysfunctional tumor suppressor genes contribute to the cancer process. Furthermore, Weinstein and others have hypothesized the phenomenon of oncogene addiction as a distinct characteristic of the malignant cell. It can be assumed that cancer cells, indeed, become dependent on such vital oncogenes. The products of these vital oncogenes, such as c-myc, may well be the Achilles heel by which targeted molecular therapy may lead to truly personalized cancer therapy. The remaining problem is the need to introduce relevant molecular diagnostic tests such as genome microarray analysis and proteomic methods, especially protein kinase identification arrays, for each individual patient. Genome wide association studies on cancers with gene analysis of single nucleotide and other mutations in functional proto-oncogenes will, hopefully, identify dysfunctional proto-oncogenes and allow the development of more specific targeted drugs directed against the protein products of these vital oncogenes. In 1984 Willis proposed a molecular and biochemical model for eukaryotic gene regulation suggesting how proto-oncogenes might function within the normal cell. That model predicted the existence of vital oncogenes and can now be used to hypothesize the biochemical and molecular mechanisms that drive the processes leading to disruption of the gene regulatory machinery, resulting in the transformation of normal cells into cancer.
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Affiliation(s)
- Rudolph E Willis
- Department of Medical Oncology, Cancer Treatment Centers of America, Eastern Regional Medical Center, 1331 Wyoming Ave, Philadelphia, PA 19124, USA; E-Mail: ; Tel.: +1-215-537-7545
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12
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Fujii W, Nishimura T, Kano K, Sugiura K, Naito K. CDK7 and CCNH Are Components of CDK-Activating Kinase and Are Required for Meiotic Progression of Pig Oocytes1. Biol Reprod 2011; 85:1124-32. [DOI: 10.1095/biolreprod.111.091801] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
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13
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Gopinathan L, Ratnacaram CK, Kaldis P. Established and novel Cdk/cyclin complexes regulating the cell cycle and development. Results Probl Cell Differ 2011; 53:365-89. [PMID: 21630153 DOI: 10.1007/978-3-642-19065-0_16] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The identification of new members in the Cdk and cyclin families, functions for many of which are still emerging, has added new facets to the cell cycle regulatory network. With roles extending beyond the classical regulation of cell cycle progression, these new players are involved in diverse processes such as transcription, neuronal function, and ion transport. Members closely related to Cdks and cyclins such as the Speedy/RINGO proteins offer fresh insights and hope for filling in the missing gaps in our understanding of cell division. This chapter will present a broad outlook on the cell cycle and its key regulators with special emphasis on the less-studied members and their emerging roles.
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Affiliation(s)
- Lakshmi Gopinathan
- Cell Division and Cancer Laboratory (PRK), Institute of Molecular and Cell Biology (IMCB), 61 Biopolis Drive, Proteos #03-09, Singapore
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Chiang CY, Tu HP, Chen YT, Chin YT, Lai TM, Chiu HC, Nieh S, Fu E. Up-regulation of retinoblastoma protein phosphorylation in gingiva after cyclosporine A treatment: an in vivo and in vitro study. J Periodontal Res 2010; 46:158-63. [DOI: 10.1111/j.1600-0765.2010.01312.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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15
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Coxon CH, Bicknell KA, Moseley FL, Brooks G. Over expression of Plk1 does not induce cell division in rat cardiac myocytes in vitro. PLoS One 2009; 4:e6752. [PMID: 19707596 PMCID: PMC2727448 DOI: 10.1371/journal.pone.0006752] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2009] [Accepted: 07/17/2009] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Mammalian cardiac myocytes withdraw from the cell cycle during post-natal development, resulting in a non-proliferating, fully differentiated adult phenotype that is unable to repair damage to the myocardium, such as occurs following a myocardial infarction. We and others previously have shown that forced expression of certain cell cycle molecules in adult cardiac myocytes can promote cell cycle progression and division in these cells. The mitotic serine/threonine kinase, Polo-like kinase-1 (Plk1), is known to phosphorylate and activate a number of mitotic targets, including Cdc2/Cyclin B1, and to promote cell division. PRINCIPAL FINDINGS The mammalian Plk family are all differentially regulated during the development of rat cardiac myocytes, with Plk1 showing the most dramatic decrease in both mRNA, protein and activity in the adult. We determined the potential of Plk1 to induce cell cycle progression and division in cultured rat cardiac myocytes. A persistent and progressive loss of Plk1 expression was observed during myocyte development that correlated with the withdrawal of adult rat cardiac myocytes from the cell cycle. Interestingly, when Plk1 was over-expressed in cardiac myocytes by adenovirus infection, it was not able to promote cell cycle progression, as determined by cell number and percent binucleation. CONCLUSIONS We conclude that, in contrast to Cdc2/Cyclin B1 over-expression, the forced expression of Plk1 in adult cardiac myocytes is not sufficient to induce cell division and myocardial repair.
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Affiliation(s)
- Carmen H. Coxon
- School of Pharmacy, University of Reading, Reading, United Kingdom
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | | | - Fleur L. Moseley
- School of Pharmacy, University of Reading, Reading, United Kingdom
| | - Gavin Brooks
- School of Pharmacy, University of Reading, Reading, United Kingdom
- School of Biological Sciences, University of Reading, Reading, United Kingdom
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16
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Differential regulation of cyclin-dependent kinase 4 (CDK4) and CDK6, evidence that CDK4 might not be activated by CDK7, and design of a CDK6 activating mutation. Mol Cell Biol 2009; 29:4188-200. [PMID: 19487459 DOI: 10.1128/mcb.01823-08] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
The homologous cyclin-dependent kinases (CDK) CDK4 and CDK6 integrate mitogenic and oncogenic signaling cascades with the cell cycle. Their activation requires binding to a D-type cyclin and then T-loop phosphorylation at T172 and T177 (respectively) by the only CDK-activating kinase identified in animal cells, cyclin H-CDK7. At odds with the existing data showing the constitutive activity of CDK7, we have recently identified the T172 phosphorylation of cyclin D-bound CDK4 as a crucial cell cycle regulatory target. Here we show that T172 phosphorylation of CDK4 is conditioned by its unique proline 173 residue. In contrast to CDK4, CDK6 does not contain such a proline and, unexpectedly, remained poorly phosphorylated and active in a variety of cells. Mutations of proline 173 did not adversely affect CDK4 activation by CDK7, but in cells they abolished CDK4 T172 phosphorylation and activity. Conversely, substituting a proline for the corresponding residue of CDK6 enforced its complete, apparently cyclin-independent T177 phosphorylation and dramatically increased its activity. These results lead us to propose that CDK4 might not be phosphorylated by CDK7 in intact cells but is more likely phosphorylated by another, presumably proline-directed kinase(s). Moreover, they provide a new model of a potentially oncogenic activating mutation of a CDK.
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17
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Cytokine signaling to the cell cycle. Immunol Res 2007; 39:173-84. [DOI: 10.1007/s12026-007-0080-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/1999] [Revised: 11/30/1999] [Accepted: 11/30/1999] [Indexed: 10/23/2022]
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18
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Larochelle S, Merrick KA, Terret ME, Wohlbold L, Barboza NM, Zhang C, Shokat KM, Jallepalli PV, Fisher RP. Requirements for Cdk7 in the assembly of Cdk1/cyclin B and activation of Cdk2 revealed by chemical genetics in human cells. Mol Cell 2007; 25:839-50. [PMID: 17386261 PMCID: PMC1858677 DOI: 10.1016/j.molcel.2007.02.003] [Citation(s) in RCA: 193] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2006] [Revised: 01/16/2007] [Accepted: 02/06/2007] [Indexed: 11/18/2022]
Abstract
Cell division is controlled by cyclin-dependent kinases (CDKs). In metazoans, S phase onset coincides with activation of Cdk2, whereas Cdk1 triggers mitosis. Both Cdk1 and -2 require cyclin binding and T loop phosphorylation for full activity. The only known CDK-activating kinase (CAK) in metazoans is Cdk7, which is also part of the transcription machinery. To test the requirements for Cdk7 in vivo, we replaced wild-type Cdk7 with a version sensitive to bulky ATP analogs in human cancer cells. Selective inhibition of Cdk7 in G1 prevents activation (but not formation) of Cdk2/cyclin complexes and delays S phase. Inhibiting Cdk7 in G2 blocks entry to mitosis and disrupts Cdk1/cyclin B complex assembly, indicating that the two steps of Cdk1 activation-cyclin binding and T loop phosphorylation-are mutually dependent. Therefore, by combining chemical genetics and homologous gene replacement in somatic cells, we reveal different modes of CDK activation by Cdk7 at two distinct execution points in the cell cycle.
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Affiliation(s)
- Stéphane Larochelle
- Molecular Biology Program, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10021
| | - Karl A. Merrick
- Molecular Biology Program, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10021
- Programs in Biochemistry, Cell and Molecular Biology, Cornell University Graduate School of Medical Sciences, 1300 York Avenue, New York, NY 10021
| | - Marie-Emilie Terret
- Molecular Biology Program, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10021
| | - Lara Wohlbold
- Molecular Biology Program, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10021
| | - Nora M. Barboza
- Molecular Biology Program, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10021
| | - Chao Zhang
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94143
| | - Kevan M. Shokat
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94143
| | - Prasad V. Jallepalli
- Molecular Biology Program, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10021
| | - Robert P. Fisher
- Molecular Biology Program, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10021
- Correspondence:
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19
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Liu QY, Wu ZL, Lv WJ, Yan YC, Li YP. Developmental expression of Cyclin H and Cdk7 in zebrafish: the essential role of Cyclin H during early embryo development. Cell Res 2007; 17:163-73. [PMID: 17287831 DOI: 10.1038/sj.cr.7310144] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Cyclin-dependent kinase 7 (Cdk7) is the catalytic subunit of the metazoan Cdk-activating kinase (CAK). Activation of Cdk7 requires its association with a regulatory subunit, Cyclin H. Although the Cdk7/Cyclin H complex has been implicated in the regulation of RNA polymerase in several species, the precise function of their orthologs in zebrafish has not been fully elucidated. In this study, we isolated from zebrafish blastula embryos two cDNAs encoding the orthologs of human Cyclin H and Cdk7, and examined the role of Cdk7/Cyclin H in zebrafish embryogenesis. Sequence analysis showed that the zebrafish Cyclin H and Cdk7 cDNAs encode proteins with 65% and 86% identity to the respective human orthologs. RT-PCR and whole-mount in situ hybridization analyses of their expression in unfertilized eggs, embryos and organs of adult fish suggested that Cyclin H and Cdk7 messages are maternally loaded. Our data also showed that their transcripts were detected throughout development. Distribution of Cyclin H transcripts was found to be ubiquitous during early stages of development and become restricted to the anterior neural tube, brain, eyes, procreate tissues, liver and heart by 5 days post-fertilization. Expression of a dominant-negative form of Cyclin H delayed the onset of zygotic transcription in the early embryo, resulting in apoptosis at 5 hours post-fertilization and leading to sever defects in tissues normally exhibiting high levels of Cyclin H expression. These results implicate Cyclin H in the regulation of the transcriptional machinery during midblastula transition and suggest that it is an essential gene in early zebrafish larval development.
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Affiliation(s)
- Qing Yun Liu
- Lab of Molecular Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Science, Chinese Academy of Sciences, Graduate School of the Chinese Academy of Sciences, 320 Yue Yang Road, Shanghai 200031, China
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20
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Bockstaele L, Coulonval K, Kooken H, Paternot S, Roger PP. Regulation of CDK4. Cell Div 2006; 1:25. [PMID: 17092340 PMCID: PMC1647274 DOI: 10.1186/1747-1028-1-25] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2006] [Accepted: 11/08/2006] [Indexed: 12/19/2022] Open
Abstract
Cyclin-dependent kinase (CDK)4 is a master integrator that couples mitogenic and antimitogenic extracellular signals with the cell cycle. It is also crucial for many oncogenic transformation processes. In this overview, we address various molecular features of CDK4 activation that are critical but remain poorly known or debated, including the regulation of its association with D-type cyclins, its subcellular location, its activating Thr172-phosphorylation and the roles of Cip/Kip CDK "inhibitors" in these processes. We have recently identified the T-loop phosphorylation of CDK4, but not of CDK6, as a determining target for cell cycle control by extracellular factors, indicating that CDK4-activating kinase(s) might have to be reconsidered.
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Affiliation(s)
- Laurence Bockstaele
- Institute of Interdisciplinary Research (IRIBHM), Faculté de Médecine, Université Libre de Bruxelles, Campus Erasme, B-1070 Brussels, Belgium
| | - Katia Coulonval
- Institute of Interdisciplinary Research (IRIBHM), Faculté de Médecine, Université Libre de Bruxelles, Campus Erasme, B-1070 Brussels, Belgium
| | - Hugues Kooken
- Institute of Interdisciplinary Research (IRIBHM), Faculté de Médecine, Université Libre de Bruxelles, Campus Erasme, B-1070 Brussels, Belgium
| | - Sabine Paternot
- Institute of Interdisciplinary Research (IRIBHM), Faculté de Médecine, Université Libre de Bruxelles, Campus Erasme, B-1070 Brussels, Belgium
| | - Pierre P Roger
- Institute of Interdisciplinary Research (IRIBHM), Faculté de Médecine, Université Libre de Bruxelles, Campus Erasme, B-1070 Brussels, Belgium
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21
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Fu Z, Larson KA, Chitta RK, Parker SA, Turk BE, Lawrence MW, Kaldis P, Galaktionov K, Cohn SM, Shabanowitz J, Hunt DF, Sturgill TW. Identification of yin-yang regulators and a phosphorylation consensus for male germ cell-associated kinase (MAK)-related kinase. Mol Cell Biol 2006; 26:8639-54. [PMID: 16954377 PMCID: PMC1636783 DOI: 10.1128/mcb.00816-06] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
MAK (male germ cell-associated protein kinase) and MRK/ICK (MAK-related kinase/intestinal cell kinase) are human homologs of Ime2p in Saccharomyces cerevisiae and of Mde3 and Pit1 in Schizosaccharomyces pombe and are similar to human cyclin-dependent kinase 2 (CDK2) and extracellular signal-regulated kinase 2 (ERK2). MAK and MRK require dual phosphorylation in a TDY motif catalyzed by an unidentified human threonine kinase and tyrosine autophosphorylation. Herein, we establish that human CDK-related kinase CCRK (cell cycle-related kinase) is an activating T157 kinase for MRK, whereas active CDK7/cyclin H/MAT1 complexes phosphorylate CDK2 but not MRK. Protein phosphatase 5 (PP5) interacts with MRK in a complex and dephosphorylates MRK at T157 in vitro and in situ. Thus, CCRK and PP5 are yin-yang regulators of T157 phosphorylation. To determine a substrate consensus, we screened a combinatorial peptide library with active MRK. MRK preferentially phosphorylates R-P-X-S/T-P sites, with the preference for arginine at position -3 (P-3) being more stringent than for prolines at P-2 and P+1. Using the consensus, we identified a putative phosphorylation site (RPLT(1080)S) for MRK in human Scythe, an antiapoptotic protein that interacts with MRK. MRK phosphorylates Scythe at T1080 in vitro as determined by site-directed mutagenesis and mass spectrometry, supporting the consensus and suggesting Scythe as a physiological substrate for MRK.
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Affiliation(s)
- Zheng Fu
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA 22908-0735, USA
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22
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Bockstaele L, Kooken H, Libert F, Paternot S, Dumont JE, de Launoit Y, Roger PP, Coulonval K. Regulated activating Thr172 phosphorylation of cyclin-dependent kinase 4(CDK4): its relationship with cyclins and CDK "inhibitors". Mol Cell Biol 2006; 26:5070-85. [PMID: 16782892 PMCID: PMC1489149 DOI: 10.1128/mcb.02006-05] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2005] [Revised: 11/11/2005] [Accepted: 04/07/2006] [Indexed: 12/25/2022] Open
Abstract
Cyclin-dependent kinase 4 (CDK4) is a master integrator of mitogenic and antimitogenic extracellular signals. It is also crucial for many oncogenic transformation processes. Various molecular features of CDK4 activation remain poorly known or debated, including the regulation of its association with D-type cyclins, its activating Thr172 phosphorylation, and the roles of Cip/Kip CDK "inhibitors" in these processes. Thr172 phosphorylation of CDK4 was reinvestigated using two-dimensional gel electrophoresis in various experimental systems, including human fibroblasts, canine thyroid epithelial cells stimulated by thyrotropin, and transfected mammalian and insect cells. Thr172 phosphorylation of CDK4 depended on prior D-type cyclin binding, but Thr172 phosphorylation was also found in p16-bound CDK4. Opposite effects of p27 on cyclin D3-CDK4 activity observed in different systems depended on its stoichiometry in this complex. Thr172-phosphorylated CDK4 was enriched in complexes containing p21 or p27, even at inhibitory levels of p27 that precluded CDK4 activity. Deletion of the p27 nuclear localization signal sequence relocalized cyclin D3-CDK4 in the cytoplasm but did not affect CDK4 phosphorylation. Within cyclin D3 complexes, T-loop phosphorylation of CDK4, but not of CDK6, was directly regulated, identifying it as a determining target for cell cycle control by extracellular factors. Collectively, these unexpected observations indicate that CDK4-activating kinase(s) should be reconsidered.
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Affiliation(s)
- Laurence Bockstaele
- Institute of Interdisciplinary Research, Université Libre de Bruxelles, Campus Erasme, B-1070 Brussels, Belgium
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23
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Fisher RP. Secrets of a double agent: CDK7 in cell-cycle control and transcription. J Cell Sci 2006; 118:5171-80. [PMID: 16280550 DOI: 10.1242/jcs.02718] [Citation(s) in RCA: 245] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In metazoans, cyclin-dependent kinase 7 (CDK7) has essential roles in both the cell-division cycle and transcription, as a CDK-activating kinase (CAK) and as a component of the general transcription factor TFIIH, respectively. Controversy over its double duty has been resolved, but questions remain. First, how does CDK7 achieve the dual substrate specificity necessary to perform both roles? Second, is there a deeper connection implied by the dichotomy of CDK7 function, for example similar mechanisms controlling cell division and gene expression, and/or actual coordination of the two processes? Enzymological studies have revealed solutions to the unusual substrate recognition problem, and there is evidence that the distinct functions of CDK7 can be regulated independently. Finally, despite divergence in their wiring, the CAK-CDK networks of budding yeast, fission yeast and metazoans all link transcriptional regulation with operation of the cell-cycle machinery. This connection might help to ensure that mRNAs encoding effectors of cell division are expressed at the right time in the cycle.
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Affiliation(s)
- Robert P Fisher
- Molecular Biology Program, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10021, USA.
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24
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Asefa B, Dermott JM, Kaldis P, Stefanisko K, Garfinkel DJ, Keller JR. p205, a potential tumor suppressor, inhibits cell proliferation via multiple pathways of cell cycle regulation. FEBS Lett 2006; 580:1205-14. [PMID: 16458891 DOI: 10.1016/j.febslet.2006.01.032] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2005] [Revised: 12/28/2005] [Accepted: 01/02/2006] [Indexed: 11/18/2022]
Abstract
p205 is a member of the interferon-inducible p200 family of proteins that regulate cell proliferation. Over-expression of p205 inhibits cell growth, although its mechanism of action is currently unknown. Therefore, we evaluated the effect of p205 on the p53 and Rb-dependent pathways of cell cycle regulation. p205 expression results in elevated levels of p21, and activates the p21 promoter in vitro in a p53-dependent manner. In addition, p205 induces increased expression of Rb, and binds directly to Rb and p53. Interestingly, p205 also induces growth inhibition independent of p53 and Rb by delaying G2/M progression in proliferating cells, and is a substrate for Cdk2 kinase activity. Finally, we have identified other binding partners of p205 by a yeast two-hybrid screen, including the paired homeodomain protein HoxB2. Taken together, our results indicate that p205 induces growth arrest by interaction with multiple transcription factors that regulate the cell cycle, including but not entirely dependent on the Rb- and p53-mediated pathways of growth inhibition.
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Affiliation(s)
- Benyam Asefa
- Laboratory of Molecular Immunoregulation, Center for Cancer Research, National Cancer Institute-Frederick, Building 560, Room 31-56, Frederick, MD 21702-1201, USA
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25
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Fu Z, Schroeder MJ, Shabanowitz J, Kaldis P, Togawa K, Rustgi AK, Hunt DF, Sturgill TW. Activation of a nuclear Cdc2-related kinase within a mitogen-activated protein kinase-like TDY motif by autophosphorylation and cyclin-dependent protein kinase-activating kinase. Mol Cell Biol 2005; 25:6047-64. [PMID: 15988018 PMCID: PMC1168834 DOI: 10.1128/mcb.25.14.6047-6064.2005] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Male germ cell-associated kinase (MAK) and intestinal cell kinase (ICK) are nuclear Cdc2-related kinases with nearly identical N-terminal catalytic domains and more divergent C-terminal noncatalytic domains. The catalytic domain is also related to mitogen-activated protein kinases (MAPKs) and contains a corresponding TDY motif. Nuclear localization of ICK requires subdomain XI and interactions of the conserved Arg-272, but not kinase activity or, surprisingly, any of the noncatalytic domain. Further, nuclear localization of ICK is required for its activation. ICK is activated by dual phosphorylation of the TDY motif. Phosphorylation of Tyr-159 in the TDY motif requires ICK autokinase activity but confers only basal kinase activity. Full activation requires additional phosphorylation of Thr-157 in the TDY motif. Coexpression of ICK with constitutively active MEK1 or MEK5 fails to increase ICK phosphorylation or activity, suggesting that MEKs are not involved. ICK and MAK are related to Ime2p in budding yeast, and cyclin-dependent protein kinase-activating kinase Cak1p has been placed genetically upstream of Ime2p. Recombinant Cak1p phosphorylates Thr-157 in the TDY motif of recombinant ICK and activates its activity in vitro. Coexpression of ICK with wild-type CAK1 but not kinase-inactive CAK1 in cells also increases ICK phosphorylation and activity. Our studies establish ICK as the prototype for a new group of MAPK-like kinases requiring dual phosphorylation at TDY motifs.
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Affiliation(s)
- Zheng Fu
- Department of Pharmacology and Internal Medicine, University of Virginia School, 1300 Jefferson Park Avenue, Charlottesville, Virginia 22908-0735, USA
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26
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Lei W, Liu F, Ness SA. Positive and negative regulation of c-Myb by cyclin D1, cyclin-dependent kinases, and p27 Kip1. Blood 2005; 105:3855-61. [PMID: 15687240 PMCID: PMC1895079 DOI: 10.1182/blood-2004-08-3342] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The c-Myb transcription factor controls differentiation and proliferation in hematopoietic and other cell types and has latent transforming activity, but little is known about its regulation during the cell cycle. Here, c-Myb was identified as part of a protein complex from human T cells containing the cyclin-dependent kinase (CDK) CDK6. Assays using model reporter constructs as well as endogenous target genes showed that the activity of c-Myb was inhibited by cyclin D1 plus CDK4 or CDK6 but stimulated by expression of the CDK inhibitors p16 Ink4a, p21 Cip1, or p27 Kip1. Mapping experiments identified a highly conserved region in c-Myb which, when transferred to the related A-Myb transcription factor, also rendered it responsive to CDKs and p27. The results suggest that c-Myb activity is directly regulated by cyclin D1 and CDKs and imply that c-Myb activity is regulated during the cell cycle in hematopoietic cells.
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Affiliation(s)
- Wanli Lei
- Department of Molecular Genetics and Microbiology, University of New Mexico, HSC, Albuquerque, NM 87131-0001, USA
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27
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Abstract
We present a comprehensive description of the dynamic behavior of CDK2 in complex with cyclin A, arrived at by analysis of a total of 0.25 micros of solvated molecular dynamics trajectories and 42 deposited CDK2 structures, and refined using other protein simulation algorithms. The CDK2-cyclin A dimer is a dynamic complex of 6 subdomains. Thermal motions are dominated by a relative twisting of the two monomers. The predominant motion within CDK2 is a "breathing" of the N-terminal and C-terminal lobes. The N-terminal lobe of cyclin A is tightly linked to the "PSTAIRE" helix of CDK2 to provide a rigid nucleus to the complex. By contrast, the "CDK-insert" region (residues 219-251) sometimes becomes highly mobile, a behavior that is observed in crystallographic analyses of CDK2 structures and that may relate to its role in recognizing diverse binding partners. We find that the three arginines that anchor phosphothreonine 160 of fully active CDK2 do not contribute equally to structural stabilization. This observation is supported by a survey of protein kinase sequences. We have also explored the physical basis of the role of the phosphate moiety in signaling by artificially modifying the charge of phosphothreonine 160 in molecular dynamics simulations. We find that phosphothreonine binding involves an active process of attraction in which both the receptor site (the arginine triad), and the phosphothreonine have a higher charge than is required to maintain an active conformation once formed. We have deposited our dynamics data to aid protein kinase inhibitor design.
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Affiliation(s)
- C Paul Barrett
- Laboratory of Molecular Biophysics, Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, United Kingdom
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28
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Henry MK, Nimbalkar D, Hohl RJ, Quelle FW. Cytokine-induced phosphoinositide 3-kinase activity promotes Cdk2 activation in factor-dependent hematopoietic cells. Exp Cell Res 2004; 299:257-66. [PMID: 15302592 DOI: 10.1016/j.yexcr.2004.06.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2004] [Revised: 06/05/2004] [Indexed: 02/06/2023]
Abstract
Cytokine growth factors regulate the proliferation of hematopoietic cells through activation of several distinct signaling pathways. We have assessed the contribution of phosphoinositide 3-kinase (PI3K) pathways to erythropoietin (Epo) and interleukin (IL)-3-induced proliferation of factor-dependent hematopoietic cells. Lack of cytokine-induced PI3K activation caused by receptor mutation or treatment with a specific inhibitor (LY294002) did not prevent proliferation but resulted in an increase in the G1 phase content and doubling time of cell cultures. The reduced proliferation of cells lacking cytokine-induced PI3K activity could be partially restored by overexpressing constitutively active Akt. Inhibition of PI3K activity decreased the proportion of cytokine-treated cells entering S phase and was associated with a significant reduction in cytokine-induced phosphorylation and activation of Cdk2. By contrast, Cdk4 activity and p27(Kip1) expression were not significantly altered by inhibition of PI3K. Together, these observations identify a mechanism through which cytokine-activated PI3K contributes to G1 to S phase progression in factor-dependent hematopoietic cells by enhancing the phosphorylation and activation of Cdk2.
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Affiliation(s)
- Matthew K Henry
- Department of Pharmacology, Carver College of Medicine, The University of Iowa, Iowa City, IA 52242, USA
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29
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Tao W, Mallard B, Karrow N, Bridle B. Construction and application of a bovine immune-endocrine cDNA microarray. Vet Immunol Immunopathol 2004; 101:1-17. [PMID: 15261689 DOI: 10.1016/j.vetimm.2003.10.011] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2003] [Revised: 10/20/2003] [Accepted: 10/29/2003] [Indexed: 11/18/2022]
Abstract
A variety of commercial DNA arrays specific for humans and rodents are widely available; however, microarrays containing well-characterized genes to study pathway-specific gene expression are not as accessible for domestic animals, such as cattle, sheep and pigs. Therefore, a small-scale application-targeted bovine immune-endocrine cDNA array was developed to evaluate genetic pathways involved in the immune-endocrine axis of cattle during periods of altered homeostasis provoked by physiological or environmental stressors, such as infection, vaccination or disease. For this purpose, 167 cDNA sequences corresponding to immune, endocrine and inflammatory response genes were collected and categorized. Positive controls included 5 housekeeping genes (glyceraldehydes-3-phosphate dehydrogenase, hypoxanthine phosphoribosyltransferase, ribosomal protein L19, beta-actin, beta2-microglobulin) and bovine genomic DNA. Negative controls were a bacterial gene (Rhodococcus equi 17-kDa virulence-associated protein) and a partial sequence of the plasmid pACYC177. In addition, RNA extracted from un-stimulated, as well as superantigen (Staphylococcus aureus enterotoxin-A, S. aureus Cowan Pansorbin Cells) and mitogen-stimulated (LPS, ConA) bovine blood leukocytes was mixed, reverse transcribed and PCR amplified using gene-specific primers. The endocrine-associated genes were amplified from cDNA derived from un-stimulated bovine hypothalamus, pituitary, adrenal and thyroid gland tissues. The array was constructed in 4 repeating grids of 180 duplicated spots by coupling the PCR amplified 213-630 bp gene fragments onto poly-l-lysine coated glass slides. The bovine immune-endocrine arrays were standardized and preliminary gene expression profiles generated using Cy3 and Cy5 labelled cDNA from un-stimulated and ConA (5 microg/ml) stimulated PBMC of 4 healthy Holstein cows (2-4 replicate arrays/cow) in a time course study. Mononuclear cell-derived cytokine and chemokine (IL-2, IL-1alpha, TNFalpha, IFN-gamma, TGFbeta-1, MCP-1, MCP-2 and MIP-3alpha) mRNA exhibited a repeatable and consistently low expression in un-stimulated cells and at least a two-fold increased expression following 6 and 24 h ConA stimulation as compared to 0 h un-stimulated controls. In contrast, expression of antigen presenting molecules, MHC-DR, MHC-DQ and MHC-DY, were consistently at least two-fold lower following 6 and 24 h ConA stimulation. The only endocrine gene with differential expression following ConA stimulation was prolactin. Additionally, due to the high level of genetic homology between ovine, swine and bovine genes, RNA similarly acquired from sheep and pigs was evaluated and similar gene expression patterns were noted. These data demonstrate that this application-targeted array containing a set of well characterized genes can be used to determine the relative gene expression corresponding to immune-endocrine responses of cattle and related species, sheep and pigs.
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Affiliation(s)
- Wenjing Tao
- Department of Pathobiology, University of Guelph, Ontario, Canada N1G 2W1.
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Liu Y, Wu C, Galaktionov K. p42, a novel cyclin-dependent kinase-activating kinase in mammalian cells. J Biol Chem 2003; 279:4507-14. [PMID: 14597612 DOI: 10.1074/jbc.m309995200] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The cyclin-dependent kinase (CDK)-activating kinase (CAK) phosphorylates a conserved threonine residue on CDKs and activates them. Two known classes of CAKs are represented by monomeric Cak1p in budding yeast Saccharomyces cerevisiae and by heterotrimeric CDK7-cyclin H-Mat1 in human and other metazoa. We report here the identification of p42, a novel CAK activity in human cells. p42 has sequence homology to both Cak1p and CDK7 groups of CAKs. p42 is essential for the phosphorylation of Thr-160 and activation of CDK2. A dominant-negative p42 mutant, T161A, and posttranscriptional gene silencing of p42 with RNA(i)-impaired Thr-160 phosphorylation and activity of CDK2. Purified p42 phosphorylated glutathione S-transferase-CDK2 at Thr-160 within the T-loop and activated its histone H1 kinase activity. Finally, p42 is indispensable for cell growth. Cells lacking p42 were incapable of growing and forming colonies whereas cells with a reduced level of p42 grew at significantly slower rates than control cells. Our findings suggest that p42 represents a novel CAK activity in mammalian cells.
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Affiliation(s)
- Yu Liu
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
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Paternot S, Coulonval K, Dumont JE, Roger PP. Cyclic AMP-dependent phosphorylation of cyclin D3-bound CDK4 determines the passage through the cell cycle restriction point in thyroid epithelial cells. J Biol Chem 2003; 278:26533-40. [PMID: 12730225 DOI: 10.1074/jbc.m302492200] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
According to current concepts, the cell cycle commitment after restriction (R) point passage requires the sustained stimulation by mitogens of the synthesis of labile d-type cyclins, which associate with cyclin-dependent kinase (CDK) 4/6 to phosphorylate pRb family proteins and sequester the CDK inhibitor p27kip1. In primary cultures of dog thyroid epithelial cells, the cAMP-dependent cell cycle induced by a sustained stimulation by thyrotropin or forskolin differs from growth factor mitogenic pathways, as cAMP does not upregulate d-type cyclins but increases p27 levels. Instead, cAMP induces the assembly of required cyclin D3-CDK4 complexes, which associate with nuclear p27. In this study, the arrest of forskolin stimulation rapidly slowed down the entry of dog thyrocytes into S phase and the phosphorylation of pRb family proteins. The pRb kinase activity, but not the formation, of the cyclin D3-CDK4-p27 complex was strongly reduced. Using two-dimensional gel electrophoresis, a phosphorylated form of CDK4 was separated. It appeared in response to forskolin and was bound to both cyclin D3 and p27, presumably reflecting the activating Thr-172 phosphorylation of CDK4. Upon forskolin withdrawal or after cycloheximide addition, this CDK4 phosphoform unexpectedly persisted in p27 complexes devoid of cyclin D3 but it disappeared from the more labile cyclin D3 complexes. These data demonstrate that the assembly of the cyclin D3-CDK4-p27 holoenzyme and the subsequent phosphorylation and activation of CDK4 depend on distinct cAMP actions. This provides a first example of a crucial regulation of CDK4 phosphorylation by a mitogenic cascade and a novel mechanism of cell cycle control at the R point.
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Affiliation(s)
- Sabine Paternot
- Institute of Interdisciplinary Research and Protein Chemistry Department, Faculté de Médecine, Université Libre de Bruxelles, Campus Erasme, B-1070 Brussels, Belgium
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Abstract
Phosphorylation of cdk2 on threonine 160 is essential for kinase activity. Mevastatin, an inhibitor of cholesterol synthesis, inhibits cell growth through inhibition of cdk2 and this has been suggested to be due to enhancement of p21 levels. In a prostate cancer cell line, PC3, mevastatin treatment led to elevated levels of p21 and caused a small increase in the p21 associated with cdk2. However, this increase in the associated p21 appeared out of proportion with the resulting dramatic inhibition of kinase activity. Using RNA interference we show that mevastatin inhibits cdk2 activity despite lack of induction of p21, p27, and p57. Instead the kinase was inhibited due to a decrease in activating phosphorylation. Phosphorylation of cdk2 from mevastatin-treated cells with exogenous cyclin-dependent kinase (cdk)-activating enzymes restored its functional activity. The only known mammalian cyclin H.cdk7.mat1 complex (cdk2-activating kinase, Cak), was not inhibited by mevastatin, suggesting either that a different CAK is responsible for cdk2 phosphorylation in vivo or that the regulation is at the level of substrate accessibility or of cdk2 dephosphorylation. These results suggest that mevastatin inhibits cdk2 activity in PC3 cells through the inhibition of Thr-160 phosphorylation of cdk2, providing a novel example of regulation of cdk2 at this level.
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Affiliation(s)
- Chinweike Ukomadu
- Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA
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Lents NH, Keenan SM, Bellone C, Baldassare JJ. Stimulation of the Raf/MEK/ERK cascade is necessary and sufficient for activation and Thr-160 phosphorylation of a nuclear-targeted CDK2. J Biol Chem 2002; 277:47469-75. [PMID: 12359725 DOI: 10.1074/jbc.m207425200] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The activity of cyclin-dependent kinase 2 is required for G(1)-S-phase progression of the eukaryotic cell cycle. In this study, we examine the activation of CDK2-cyclin E by constructing a CDK2 that is constitutively targeted to the nucleus. Activation of CDK2 requires the removal of two inhibitory phosphates (Thr-14 and Tyr-15) and the addition of one activating phosphate (Thr-160) by a nuclear localized CDK-activating kinase, which is thought to be constitutively active. Surprisingly, nuclear localized CDK2-NLS and CDK2-NLS(A14,F15), which lacks the inhibitory phosphorylation sites, require serum to become active, despite complexing with expressed cyclin E. We show that inhibition of mitogen-mediated ERK activation by treatment with U0126, a selective MEK inhibitor, or expression of dominant-negative ERK markedly reduces the phosphorylation of Thr-160 and enzymatic activity of both CDK2-NLS constructs. Consistent with a role for ERK in Thr-160 phosphorylation, expression of constitutively active Raf-1 induces Thr-160 phosphorylation of CDK2-NLS in serum-arrested cells, an effect that is blocked by treatment with U0126. Taken together, these data show a new role for ERK in G1 cell cycle progression: In addition to its role in stimulating cyclin D1 expression and nuclear translocation of CDK2, ERK regulates Thr-160 phosphorylation of CDK2-cyclin E.
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Affiliation(s)
- Nathan H Lents
- Department of Pharmacological and Physiological Sciences, Saint Louis University School of Medicine, Saint Louis, Missouri 63104, USA
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Jona G, Livi LL, Gileadi O. Mutations in the RING domain of TFB3, a subunit of yeast transcription factor IIH, reveal a role in cell cycle progression. J Biol Chem 2002; 277:39409-16. [PMID: 12176978 DOI: 10.1074/jbc.m202733200] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The RNA polymerase II general transcription factor TFIIH is composed of 9 known subunits and possesses DNA helicase and protein kinase activities. The kinase subunits of TFIIH in animal cells, Cdk7, cyclin H, and MAT1, were independently isolated as an activity termed CAK (Cdk-activating kinase), which phosphorylates and activates cell cycle kinases. However, CAK activity of TFIIH subunits could not be demonstrated in budding yeast. TFB3, the 38-kDa subunit of yeast TFIIH, is the homolog of mammalian MAT1. By random mutagenesis we have isolated a temperature-sensitive mutation in the conserved RING domain. The mutant Tfb3 protein associates less efficiently with the kinase moiety of TFIIH than the wild type protein. In contrast to lethal mutants in other subunits of TFIIH, this mutation does not impair general transcription. Transcription of CLB2, and possibly other genes, is reduced in the mutant. At the restrictive temperature, the cells display a defect in cell cycle progression, which is manifest at more than one phase of the cycle. To conclude, in the present study we bring another demonstration of the multifunctional nature of TFIIH.
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Affiliation(s)
- Ghil Jona
- Department of Molecular Genetics, The Weizmann Institute of Science, Rehovot 76100, Israel
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35
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De Smedt V, Poulhe R, Cayla X, Dessauge F, Karaiskou A, Jessus C, Ozon R. Thr-161 phosphorylation of monomeric Cdc2. Regulation by protein phosphatase 2C in Xenopus oocytes. J Biol Chem 2002; 277:28592-600. [PMID: 12036957 DOI: 10.1074/jbc.m202742200] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Fully grown Xenopus oocyte is arrested at prophase I of meiosis. Re-entry into meiosis depends on the activation of MPF (M-phase promoting factor or cyclin B.Cdc2 complex), triggered by progesterone. The prophase-arrested oocyte contains a store of Cdc2. Most of the protein is present as a monomer whereas a minor fraction, called pre-MPF, is found to be associated with cyclin B. Activation of Cdc2 depends on two key events: cyclin binding and an activating phosphorylation on Thr-161 residue located in the T-loop. To get new insights into the regulation of Thr-161 phosphorylation of Cdc2, monomeric Cdc2 was isolated from prophase oocytes. Based on its activation upon cyclin addition and detection by an antibody directed specifically against Cdc2 phosphorylated on Thr-161, we show for the first time that the prophase oocyte contains a significant amount of monomeric Cdc2 phosphorylated on Thr-161. PP2C, a Mg2+-dependent phosphatase, negatively controls Thr-161 phosphorylation of Cdc2. The unexpected presence of a population of free Cdc2 already phosphorylated on Thr-161 could contribute to the generation of the Cdc2 kinase activity threshold required to initiate MPF amplification.
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Affiliation(s)
- Veronique De Smedt
- Laboratoire de Biologie du Développement, Institut de la Recherche Agronomique/Unité Mixte de Recherche-CNRS 7622, Université Pierre et Marie Curie, Boite 24, 4 Place Jussieu, 75252 Paris cedex 05, France
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Oelgeschläger T. Regulation of RNA polymerase II activity by CTD phosphorylation and cell cycle control. J Cell Physiol 2002; 190:160-9. [PMID: 11807820 DOI: 10.1002/jcp.10058] [Citation(s) in RCA: 116] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The carboxyl-terminal domain (CTD) of the largest subunit of mammalian RNA polymerase II (RNAP II) consists of 52 repeats of a consensus heptapeptide and is subject to phosphorylation and dephosphorylation events during each round of transcription. RNAP II activity is regulated during the cell cycle and cell cycle-dependend changes in RNAP II activity correlate well with CTD phosphorylation. In addition, global changes in the CTD phosphorylation status are observed in response to mitogenic or cytostatic signals such as growth factors, mitogens and DNA-damaging agents. Several CTD kinases are members of the cyclin-dependent kinase (CDK) superfamily and associate with transcription initiation complexes. Other CTD kinases implicated in cell cycle regulation include the mitogen-activated protein kinases ERK-1/2 and the c-Abl tyrosine kinase. These observations suggest that reversible RNAP II CTD phosphorylation may play a key role in linking cell cycle regulatory events to coordinated changes in transcription.
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Affiliation(s)
- Thomas Oelgeschläger
- Eukaryotic Gene Regulation Laboratory, Marie Curie Research Institute, The Chart, Oxted, Surrey, United Kingdom.
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37
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Riley D, Carragher NO, Frame MC, Wyke JA. The mechanism of cell cycle regulation by v-Src. Oncogene 2001; 20:5941-50. [PMID: 11593401 DOI: 10.1038/sj.onc.1204826] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2001] [Revised: 07/04/2001] [Accepted: 07/11/2001] [Indexed: 11/09/2022]
Abstract
The tyrosine kinase oncoprotein v-Src can overcome the requirements for serum growth factors and anchorage which restrain normal cell growth. Here we investigated the biochemical mechanisms whereby v-Src induces quiescent cells to enter S phase in the absence of serum mitogens. Activating a temperature sensitive v-Src in quiescent cells sequentially induced cyclins D1, E and A and also down regulated p27. We addressed whether p27 down regulation was required to activate cyclin D1/CDK4/6 or cyclin E/CDK2 by engineering cells with inducible p27. Both S phase entry and activation of cyclin/CDKs were inhibited by over expression of p27. Using cells engineered with inducible p16 we showed that Cyclin D/CDK4/6 activity was required for v-Src to increase expression of cyclin A but not cyclin E. To determine which downstream kinases mediated these effects of v-Src we added pharmacological inhibitors of phosphatidylinositol 3-kinase (PI3-K), LY294002 or mitogen activated protein kinase kinase (MEK), U0126. PI3-K was required for v-Src to activate MEK and MEK was required for v-Src to increase expression of cyclins D1 and E. However, the MEK inhibitor prevented p27 protein down regulation whereas the PI3-K inhibitor did not. This was because reduced PI3-K activity lead to proteolytic degradation of p27.
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Affiliation(s)
- D Riley
- The Beatson Institute for Cancer Research, CRC Beatson Laboratories, Garscube Estate, Switchback Road, Bearsden, Glasgow, G61 1BD, UK
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38
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Eapen AK, Henry MK, Quelle DE, Quelle FW. Dna damage-induced G(1) arrest in hematopoietic cells is overridden following phosphatidylinositol 3-kinase-dependent activation of cyclin-dependent kinase 2. Mol Cell Biol 2001; 21:6113-21. [PMID: 11509654 PMCID: PMC87328 DOI: 10.1128/mcb.21.18.6113-6121.2001] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Exposure of hematopoietic cells to DNA-damaging agents induces p53-independent cell cycle arrest at a G(1) checkpoint. Previously, we have shown that this growth arrest can be overridden by cytokine growth factors, such as erythropoietin or interleukin-3, through activation of a phosphatidylinositol 3-kinase (PI 3-kinase)/Akt-dependent signaling pathway. Here, we show that gamma-irradiated murine myeloid 32D cells arrest in G(1) with active cyclin D-cyclin-dependent kinase 4 (Cdk4) but with inactive cyclin E-Cdk2 kinases. The arrest was associated with elevated levels of the Cdk inhibitors p21(Cip1) and p27(Kip1), yet neither was associated with Cdk2. Instead, irradiation-induced inhibition of cyclin E-Cdk2 correlated with absence of the activating threonine-160 phosphorylation on Cdk2. Cytokine treatment of irradiated cells induced Cdk2 phosphorylation and activation, and cells entered into S phase despite sustained high-level expression of p21 and p27. Notably, the PI 3-kinase inhibitor, LY294002, completely blocked cytokine-induced Cdk2 activation and cell growth in irradiated 32D cells but not in nonirradiated cells. Together, these findings demonstrate a novel mechanism underlying the DNA damage-induced G(1) arrest of hematopoietic cells, that is, inhibition of Cdk2 phosphorylation and activation. These observations link PI 3-kinase signaling pathways with the regulation of Cdk2 activity.
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Affiliation(s)
- A K Eapen
- Department of Pharmacology, The University of Iowa College of Medicine, Iowa City, Iowa 52242, USA
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39
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Rossi DJ, Londesborough A, Korsisaari N, Pihlak A, Lehtonen E, Henkemeyer M, Mäkelä TP. Inability to enter S phase and defective RNA polymerase II CTD phosphorylation in mice lacking Mat1. EMBO J 2001; 20:2844-56. [PMID: 11387217 PMCID: PMC125252 DOI: 10.1093/emboj/20.11.2844] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The trimeric Cdk7-cyclin H-Mat1 complex comprises the kinase subunit of basal transcription factor TFIIH and has been shown to function as a cyclin-dependent kinase (Cdk)-activating kinase. Herein we report that disruption of the murine Mat1 gene leads to peri-implantation lethality coincident with depletion of maternal Mat1 protein. In culture, Mat1(-/-) blastocysts gave rise to viable post-mitotic trophoblast giant cells while mitotic lineages failed to proliferate and survive. In contrast to wild-type trophoblast giant cells, Mat1(-/-) cells exhibited a rapid arrest in endoreduplication, which was characterized by an inability to enter S phase. Additionally, Mat1(-/-) cells exhibited defects in phosphorylation of the C-terminal domain (CTD) of RNA polymerase II on both Ser5 and Ser2 of the heptapeptide repeat. Despite this, Mat1(-/-) cells demonstrated apparent transcriptional and translational integrity. These data indicate an essential role for Mat1 in progression through the endocycle and suggest that while Mat1 modulates CTD phosphorylation, it does not appear to be essential for RNA polymerase II-mediated transcription.
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Affiliation(s)
- Derrick J. Rossi
- Molecular Cancer Biology Research Program, Biomedicum Helsinki and Haartman Institute, University of Helsinki, PO Box 63, 00014 Helsinki, HUCH Laboratory Diagnostics, Helsinki University Central Hospital, PO Box 401, 00029 HYKS, Finland and Center for Developmental Biology, University of Texas Southwestern Medical Center, Dallas, TX 75235-9133, USA Corresponding author e-mail:
A.Londesborough and N.Korsisaari contributed equally to this work
| | - Anou Londesborough
- Molecular Cancer Biology Research Program, Biomedicum Helsinki and Haartman Institute, University of Helsinki, PO Box 63, 00014 Helsinki, HUCH Laboratory Diagnostics, Helsinki University Central Hospital, PO Box 401, 00029 HYKS, Finland and Center for Developmental Biology, University of Texas Southwestern Medical Center, Dallas, TX 75235-9133, USA Corresponding author e-mail:
A.Londesborough and N.Korsisaari contributed equally to this work
| | - Nina Korsisaari
- Molecular Cancer Biology Research Program, Biomedicum Helsinki and Haartman Institute, University of Helsinki, PO Box 63, 00014 Helsinki, HUCH Laboratory Diagnostics, Helsinki University Central Hospital, PO Box 401, 00029 HYKS, Finland and Center for Developmental Biology, University of Texas Southwestern Medical Center, Dallas, TX 75235-9133, USA Corresponding author e-mail:
A.Londesborough and N.Korsisaari contributed equally to this work
| | - Arno Pihlak
- Molecular Cancer Biology Research Program, Biomedicum Helsinki and Haartman Institute, University of Helsinki, PO Box 63, 00014 Helsinki, HUCH Laboratory Diagnostics, Helsinki University Central Hospital, PO Box 401, 00029 HYKS, Finland and Center for Developmental Biology, University of Texas Southwestern Medical Center, Dallas, TX 75235-9133, USA Corresponding author e-mail:
A.Londesborough and N.Korsisaari contributed equally to this work
| | - Eero Lehtonen
- Molecular Cancer Biology Research Program, Biomedicum Helsinki and Haartman Institute, University of Helsinki, PO Box 63, 00014 Helsinki, HUCH Laboratory Diagnostics, Helsinki University Central Hospital, PO Box 401, 00029 HYKS, Finland and Center for Developmental Biology, University of Texas Southwestern Medical Center, Dallas, TX 75235-9133, USA Corresponding author e-mail:
A.Londesborough and N.Korsisaari contributed equally to this work
| | - Mark Henkemeyer
- Molecular Cancer Biology Research Program, Biomedicum Helsinki and Haartman Institute, University of Helsinki, PO Box 63, 00014 Helsinki, HUCH Laboratory Diagnostics, Helsinki University Central Hospital, PO Box 401, 00029 HYKS, Finland and Center for Developmental Biology, University of Texas Southwestern Medical Center, Dallas, TX 75235-9133, USA Corresponding author e-mail:
A.Londesborough and N.Korsisaari contributed equally to this work
| | - Tomi P. Mäkelä
- Molecular Cancer Biology Research Program, Biomedicum Helsinki and Haartman Institute, University of Helsinki, PO Box 63, 00014 Helsinki, HUCH Laboratory Diagnostics, Helsinki University Central Hospital, PO Box 401, 00029 HYKS, Finland and Center for Developmental Biology, University of Texas Southwestern Medical Center, Dallas, TX 75235-9133, USA Corresponding author e-mail:
A.Londesborough and N.Korsisaari contributed equally to this work
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Hermand D, Westerling T, Pihlak A, Thuret JY, Vallenius T, Tiainen M, Vandenhaute J, Cottarel G, Mann C, Mäkelä TP. Specificity of Cdk activation in vivo by the two Caks Mcs6 and Csk1 in fission yeast. EMBO J 2001; 20:82-90. [PMID: 11226158 PMCID: PMC140202 DOI: 10.1093/emboj/20.1.82] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Activating phosphorylation of cyclin-dependent kinases (Cdks) is mediated by at least two structurally distinct types of Cdk-activating kinases (Caks): the trimeric Cdk7-cyclin H-Mat1 complex in metazoans and the single-subunit Cak1 in budding yeast. Fission yeast has both Cak types: Mcs6 is a Cdk7 ortholog and Csk1 a single-subunit kinase. Both phosphorylate Cdks in vitro and rescue a thermosensitive budding yeast CAK1 strain. However, this apparent redundancy is not observed in fission yeast in vivo. We have identified mutants that exhibit phenotypes attributable to defects in either Mcs6-activating phosphorylation or in Cdc2-activating phosphorylation. Mcs6, human Cdk7 and budding yeast Cak1 were all active as Caks for Cdc2 when expressed in fission yeast. Although Csk1 could activate Mcs6, it was unable to activate Cdc2. Biochemical experiments supported these genetic results: budding yeast Cak1 could bind and phosphorylate Cdc2 from fission yeast lysates, whereas fission yeast Csk1 could not. These results indicate that Mcs6 is the direct activator of Cdc2, and Csk1 only activates Mcs6. This demonstrates in vivo specificity in Cdk activation by Caks.
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Affiliation(s)
- Damien Hermand
- Haartman Institute & Biocentrum Helsinki, University of Helsinki, 00014 Helsinki, HUCH Laboratory Diagnostics, 00029 HYKS, Finland, Laboratoire de Génétique Moléculaire (GEMO), University of Namur (FUNDP), 61 Rue de Bruxelles, 5000 Namur, Belgium, Service de Biochimie et Genetique Moléculaire, CEA/Saclay, F-91191 Gif-sur-Yvette Cedex, France and Genome Therapeutics Corp., 100 Beaver Street, Waltham, MA 02154, USA Corresponding author e-mail: D.Hermand & T.Westerling and A.Pihlak & J.-Y.Thuret, respectively, contributed equally to this work
| | - Thomas Westerling
- Haartman Institute & Biocentrum Helsinki, University of Helsinki, 00014 Helsinki, HUCH Laboratory Diagnostics, 00029 HYKS, Finland, Laboratoire de Génétique Moléculaire (GEMO), University of Namur (FUNDP), 61 Rue de Bruxelles, 5000 Namur, Belgium, Service de Biochimie et Genetique Moléculaire, CEA/Saclay, F-91191 Gif-sur-Yvette Cedex, France and Genome Therapeutics Corp., 100 Beaver Street, Waltham, MA 02154, USA Corresponding author e-mail: D.Hermand & T.Westerling and A.Pihlak & J.-Y.Thuret, respectively, contributed equally to this work
| | - Arno Pihlak
- Haartman Institute & Biocentrum Helsinki, University of Helsinki, 00014 Helsinki, HUCH Laboratory Diagnostics, 00029 HYKS, Finland, Laboratoire de Génétique Moléculaire (GEMO), University of Namur (FUNDP), 61 Rue de Bruxelles, 5000 Namur, Belgium, Service de Biochimie et Genetique Moléculaire, CEA/Saclay, F-91191 Gif-sur-Yvette Cedex, France and Genome Therapeutics Corp., 100 Beaver Street, Waltham, MA 02154, USA Corresponding author e-mail: D.Hermand & T.Westerling and A.Pihlak & J.-Y.Thuret, respectively, contributed equally to this work
| | - Jean-Yves Thuret
- Haartman Institute & Biocentrum Helsinki, University of Helsinki, 00014 Helsinki, HUCH Laboratory Diagnostics, 00029 HYKS, Finland, Laboratoire de Génétique Moléculaire (GEMO), University of Namur (FUNDP), 61 Rue de Bruxelles, 5000 Namur, Belgium, Service de Biochimie et Genetique Moléculaire, CEA/Saclay, F-91191 Gif-sur-Yvette Cedex, France and Genome Therapeutics Corp., 100 Beaver Street, Waltham, MA 02154, USA Corresponding author e-mail: D.Hermand & T.Westerling and A.Pihlak & J.-Y.Thuret, respectively, contributed equally to this work
| | - Tea Vallenius
- Haartman Institute & Biocentrum Helsinki, University of Helsinki, 00014 Helsinki, HUCH Laboratory Diagnostics, 00029 HYKS, Finland, Laboratoire de Génétique Moléculaire (GEMO), University of Namur (FUNDP), 61 Rue de Bruxelles, 5000 Namur, Belgium, Service de Biochimie et Genetique Moléculaire, CEA/Saclay, F-91191 Gif-sur-Yvette Cedex, France and Genome Therapeutics Corp., 100 Beaver Street, Waltham, MA 02154, USA Corresponding author e-mail: D.Hermand & T.Westerling and A.Pihlak & J.-Y.Thuret, respectively, contributed equally to this work
| | - Marianne Tiainen
- Haartman Institute & Biocentrum Helsinki, University of Helsinki, 00014 Helsinki, HUCH Laboratory Diagnostics, 00029 HYKS, Finland, Laboratoire de Génétique Moléculaire (GEMO), University of Namur (FUNDP), 61 Rue de Bruxelles, 5000 Namur, Belgium, Service de Biochimie et Genetique Moléculaire, CEA/Saclay, F-91191 Gif-sur-Yvette Cedex, France and Genome Therapeutics Corp., 100 Beaver Street, Waltham, MA 02154, USA Corresponding author e-mail: D.Hermand & T.Westerling and A.Pihlak & J.-Y.Thuret, respectively, contributed equally to this work
| | - Jean Vandenhaute
- Haartman Institute & Biocentrum Helsinki, University of Helsinki, 00014 Helsinki, HUCH Laboratory Diagnostics, 00029 HYKS, Finland, Laboratoire de Génétique Moléculaire (GEMO), University of Namur (FUNDP), 61 Rue de Bruxelles, 5000 Namur, Belgium, Service de Biochimie et Genetique Moléculaire, CEA/Saclay, F-91191 Gif-sur-Yvette Cedex, France and Genome Therapeutics Corp., 100 Beaver Street, Waltham, MA 02154, USA Corresponding author e-mail: D.Hermand & T.Westerling and A.Pihlak & J.-Y.Thuret, respectively, contributed equally to this work
| | - Guillaume Cottarel
- Haartman Institute & Biocentrum Helsinki, University of Helsinki, 00014 Helsinki, HUCH Laboratory Diagnostics, 00029 HYKS, Finland, Laboratoire de Génétique Moléculaire (GEMO), University of Namur (FUNDP), 61 Rue de Bruxelles, 5000 Namur, Belgium, Service de Biochimie et Genetique Moléculaire, CEA/Saclay, F-91191 Gif-sur-Yvette Cedex, France and Genome Therapeutics Corp., 100 Beaver Street, Waltham, MA 02154, USA Corresponding author e-mail: D.Hermand & T.Westerling and A.Pihlak & J.-Y.Thuret, respectively, contributed equally to this work
| | - Carl Mann
- Haartman Institute & Biocentrum Helsinki, University of Helsinki, 00014 Helsinki, HUCH Laboratory Diagnostics, 00029 HYKS, Finland, Laboratoire de Génétique Moléculaire (GEMO), University of Namur (FUNDP), 61 Rue de Bruxelles, 5000 Namur, Belgium, Service de Biochimie et Genetique Moléculaire, CEA/Saclay, F-91191 Gif-sur-Yvette Cedex, France and Genome Therapeutics Corp., 100 Beaver Street, Waltham, MA 02154, USA Corresponding author e-mail: D.Hermand & T.Westerling and A.Pihlak & J.-Y.Thuret, respectively, contributed equally to this work
| | - Tomi P. Mäkelä
- Haartman Institute & Biocentrum Helsinki, University of Helsinki, 00014 Helsinki, HUCH Laboratory Diagnostics, 00029 HYKS, Finland, Laboratoire de Génétique Moléculaire (GEMO), University of Namur (FUNDP), 61 Rue de Bruxelles, 5000 Namur, Belgium, Service de Biochimie et Genetique Moléculaire, CEA/Saclay, F-91191 Gif-sur-Yvette Cedex, France and Genome Therapeutics Corp., 100 Beaver Street, Waltham, MA 02154, USA Corresponding author e-mail: D.Hermand & T.Westerling and A.Pihlak & J.-Y.Thuret, respectively, contributed equally to this work
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41
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Cheng A, Kaldis P, Solomon MJ. Dephosphorylation of human cyclin-dependent kinases by protein phosphatase type 2C alpha and beta 2 isoforms. J Biol Chem 2000; 275:34744-9. [PMID: 10934208 DOI: 10.1074/jbc.m006210200] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We previously reported that the activating phosphorylation on cyclin-dependent kinases in yeast (Cdc28p) and in humans (Cdk2) is removed by type 2C protein phosphatases. In this study, we characterize this PP2C-like activity in HeLa cell extract and determine that it is due to PP2C beta 2, a novel PP2C beta isoform, and to PP2C alpha. PP2C alpha and PP2C beta 2 co-purified with Mg(2+)-dependent Cdk2/Cdk6 phosphatase activity in DEAE-Sepharose, Superdex-200, and Mono Q chromatographies. Moreover, purified recombinant PP2C alpha and PP2C beta 2 proteins efficiently dephosphorylated monomeric Cdk2/Cdk6 in vitro. The dephosphorylation of Cdk2 and Cdk6 by PP2C isoforms was inhibited by the binding of cyclins. We found that the PP2C-like activity in HeLa cell extract, partially purified HeLa PP2C alpha and PP2C beta 2 isoforms, and the recombinant PP2Cs exhibited a comparable substrate preference for a phosphothreonine containing substrate, consistent with the conservation of threonine residues at the site of activating phosphorylation in CDKs.
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Affiliation(s)
- A Cheng
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, Connecticut 06520-8114, USA
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