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López-Hernández MN, Vázquez-Ramos JM. Maize CDKA2;1a and CDKB1;1 kinases have different requirements for their activation and participate in substrate recognition. FEBS J 2023; 290:2463-2488. [PMID: 36259272 DOI: 10.1111/febs.16659] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Revised: 09/13/2022] [Accepted: 10/18/2022] [Indexed: 05/04/2023]
Abstract
Cyclin-dependent kinases (CDKs), in association with cyclins, control cell cycle progression by phosphorylating a large number of substrates. In animals, activation of CDKs regularly requires both the association with a cyclin and then phosphorylation of a highly conserved threonine residue in the CDK activation loop (the classical mechanism), mediated by a CDK-activating kinase (CAK). In addition to this typical mechanism of activation, some CDKs can also be activated by the association of a cyclin to a monomeric CDK previously phosphorylated by CAK although not all CDKs can be activated by this mechanism. In animals and yeast, cyclin, in addition to being required for CDK activation, provides substrate specificity to the cyclin/CDK complex; however, in plants both the mechanisms of CDKs activation and the relevance of the CDK-associated cyclin for substrate targeting have been poorly studied. In this work, by co-expressing proteins in E. coli, we studied maize CDKA2;1a and CDKB1;1, two of the main types of CDKs that control the cell cycle in plants. These kinases could be activated by the classical mechanism and by the association of CycD2;2a to a phosphorylated intermediate in its activation loop, a previously unproven mechanism for the activation of plant CDKs. Unlike CDKA2;1a, CDKB1;1 did not require CAK for its activation, since it autophosphorylated in its activation loop. Phosphorylation of CDKB1;1 and association of CycD2;2 was not enough for its full activation as association of maize CKS, a scaffolding protein, differentially stimulated substrate phosphorylation. Our results suggest that both CDKs participate in substrate recognition.
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Affiliation(s)
| | - Jorge M Vázquez-Ramos
- Facultad de Química, Departamento de Bioquímica, Universidad Nacional Autónoma de México, Mexico
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2
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Luo S, Su T, Zhou X, Hu WX, Hu J. Chromosome 1 instability in multiple myeloma: Aberrant gene expression, pathogenesis, and potential therapeutic target. FASEB J 2022; 36:e22341. [PMID: 35579877 DOI: 10.1096/fj.202200354] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Accepted: 04/25/2022] [Indexed: 11/11/2022]
Abstract
Multiple myeloma (MM), the terminally differentiated B cells malignancy, is widely considered to be incurable since many patients have either developed drug resistance or experienced an eventual relapse. To develop precise and efficient therapeutic strategies, we must understand the pathogenesis of MM. Thus, unveiling the driver events of MM and its further clonal evolution will help us understand this complicated disease. Chromosome 1 instabilities are the most common genomic alterations that participate in MM pathogenesis, and these aberrations of chromosome 1 mainly include copy number variations and structural changes. The chromosome 1q gains/amplifications and 1p deletions are the most frequent structural changes of chromosomes in MM. In this review, we intend to focus on the genes that are affected by chromosome 1 instability: some tumor suppressors were lost or down regulated in 1p deletions, and others that contributed to tumorigenesis were upregulated in 1q gains/amplifications. We have summarized their biological function as well as their roles in the MM pathogenesis, hoping to uncover potential novel therapeutical targets and promote the development of future therapeutic approaches.
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Affiliation(s)
- Saiqun Luo
- Molecular Biology Research Center, School of Life Sciences, Central South University, Changsha, China
| | - Tao Su
- Department of Hematology, Xiangya Hospital, Central South University, Changsha, China
| | - Xiang Zhou
- Molecular Biology Research Center, School of Life Sciences, Central South University, Changsha, China
| | - Wei-Xin Hu
- Molecular Biology Research Center, School of Life Sciences, Central South University, Changsha, China
| | - Jingping Hu
- Molecular Biology Research Center, School of Life Sciences, Central South University, Changsha, China
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Shi W, Huang Q, Xie J, Wang H, Yu X, Zhou Y. CKS1B as Drug Resistance-Inducing Gene-A Potential Target to Improve Cancer Therapy. Front Oncol 2020; 10:582451. [PMID: 33102238 PMCID: PMC7545642 DOI: 10.3389/fonc.2020.582451] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Accepted: 08/28/2020] [Indexed: 12/18/2022] Open
Abstract
Cancer is a threat to human health and life. Although previously centered on chemical drug treatments, cancer treatment has entered an era of precision targeted therapy. Targeted therapy entails precise guidance, allowing the selective killing of cancer cells and thereby reducing damage to healthy tissues. Therefore, the need to explore potential targets for tumor treatment is vital. Cyclin-dependent kinase regulatory subunit 1B (CKS1B), a member of the conserved cyclin kinase subunit 1 (CKS1) protein family, plays an essential role in cell cycling. A large number of studies have shown that CKS1B is associated with the pathogenesis of many human cancers and closely related to drug resistance. Here, we describe the current understanding of the cellular functions of CKS1B and its underlying mechanisms, summarize a recent study of CKS1B as a target for cancer treatment and discuss the potential of CKS1B as a therapeutic target.
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Affiliation(s)
- Wenwen Shi
- Key Laboratory of Molecular Target and Clinical Pharmacology, The State Key Laboratory of Respiratory Disease, School of Pharmaceutical Sciences and The Fifth Affiliated Hospital, Guangzhou Medical University, Guangzhou, China
| | - Qiudi Huang
- Key Laboratory of Molecular Target and Clinical Pharmacology, The State Key Laboratory of Respiratory Disease, School of Pharmaceutical Sciences and The Fifth Affiliated Hospital, Guangzhou Medical University, Guangzhou, China
| | - Jiacui Xie
- Key Laboratory of Molecular Target and Clinical Pharmacology, The State Key Laboratory of Respiratory Disease, School of Pharmaceutical Sciences and The Fifth Affiliated Hospital, Guangzhou Medical University, Guangzhou, China
| | - He Wang
- Center of Cancer Research, The Second Affiliated Hospital, Guangzhou Medical University, Guangzhou, China
| | - Xiyong Yu
- Key Laboratory of Molecular Target and Clinical Pharmacology, The State Key Laboratory of Respiratory Disease, School of Pharmaceutical Sciences and The Fifth Affiliated Hospital, Guangzhou Medical University, Guangzhou, China
| | - Yi Zhou
- Key Laboratory of Molecular Target and Clinical Pharmacology, The State Key Laboratory of Respiratory Disease, School of Pharmaceutical Sciences and The Fifth Affiliated Hospital, Guangzhou Medical University, Guangzhou, China
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Zamani-Ahmadmahmudi M, Nassiri SM, Soltaninezhad F. Development of an RNA sequencing-based prognostic gene signature in multiple myeloma. Br J Haematol 2020; 192:310-321. [PMID: 32410217 DOI: 10.1111/bjh.16744] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Accepted: 04/22/2020] [Indexed: 01/08/2023]
Abstract
Several prognostic gene signatures have been developed to predict the clinical outcome in patients with multiple myeloma (MM). The most salient disadvantage of the previous signatures is their non-reproducibility in external datasets. Given the disadvantages and the superiority of RNA sequencing over microarrays in transcriptome profiling to produce more reliable outputs, we sought to develop a reproducible RNA sequencing-based prognostic gene signature for MM. Genes significantly associated with survival were detected in The Cancer Genome Atlas (TCGA) MM RNA sequencing dataset (MMRF-CoMMpass) (n = 412) through a strict pipeline containing four rigid filters. The reproducibility of the selected genes was checked in an independent dataset (GSE24080), containing 559 newly diagnosed patients with MM. The RNA sequencing-based prognostic signature was reconstructed based on the final genes in the training dataset (MMRF-CoMMpass) and externally validated in five independent datasets (i.e. GSE2658, GSE13624, GSE9782, GSE6477 and GSE57317), containing 1461 MM cases. The RNA sequencing-based signature was reconstructed using finally five reproducible genes: CCT2, CKS1B, PRKDC, NONO and UBE2A. This signature was able to robustly discriminate between low- and high-risk patients in both training and validation datasets (Ps ≤ 0·001). Our signature was also independent of and more powerful than the routine MM prognostic factors (i.e. β2-microglobulin, albumin, age and sex) (Ps ≤ 0·01). Treatment regimens had no effect on RNA sequencing-based signature insofar as this signature succeeded in predicting the clinical outcome in various treatment groups (Ps ≤ 0·001).
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Affiliation(s)
- Mohamad Zamani-Ahmadmahmudi
- Department of Clinical Science, Faculty of Veterinary Medicine, Shahid Bahonar University of Kerman, Kerman, Iran
| | - Seyed Mahdi Nassiri
- Department of Clinical Pathology, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran
| | - Fatemeh Soltaninezhad
- Department of Clinical Science, Faculty of Veterinary Medicine, Shahid Bahonar University of Kerman, Kerman, Iran
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5
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Gheldof A, Mackay DJG, Cheong Y, Verpoest W. Genetic diagnosis of subfertility: the impact of meiosis and maternal effects. J Med Genet 2019; 56:271-282. [PMID: 30728173 PMCID: PMC6581078 DOI: 10.1136/jmedgenet-2018-105513] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2018] [Revised: 12/24/2018] [Accepted: 12/27/2018] [Indexed: 02/06/2023]
Abstract
During reproductive age, approximately one in seven couples are confronted with fertility problems. While the aetiology is diverse, including infections, metabolic diseases, hormonal imbalances and iatrogenic effects, it is becoming increasingly clear that genetic factors have a significant contribution. Due to the complex nature of infertility that often hints at a multifactorial cause, the search for potentially causal gene mutations in idiopathic infertile couples has remained difficult. Idiopathic infertility patients with a suspicion of an underlying genetic cause can be expected to have mutations in genes that do not readily affect general health but are only essential in certain processes connected to fertility. In this review, we specifically focus on genes involved in meiosis and maternal-effect processes, which are of critical importance for reproduction and initial embryonic development. We give an overview of genes that have already been linked to infertility in human, as well as good candidates which have been described in other organisms. Finally, we propose a phenotypic range in which we expect an optimal diagnostic yield of a meiotic/maternal-effect gene panel.
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Affiliation(s)
- Alexander Gheldof
- Center for Medical Genetics, Universitair Ziekenhuis Brussel, Brussels, Belgium
- Reproduction and Genetics Department, Vrije Universiteit Brussel, Brussels, Belgium
| | - Deborah J G Mackay
- Faculty of Medicine, University of Southampton, Southampton University Hospital, Southampton, UK
| | - Ying Cheong
- Complete Fertility, Human Development of Health, Faculty of Medicine, University of Southampton, Southampton, UK
| | - Willem Verpoest
- Reproduction and Genetics Department, Vrije Universiteit Brussel, Brussels, Belgium
- Center for Reproductive Medicine, Universitair Ziekenhuis Brussel, Brussels, Belgium
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Dehghanifard A, Kaviani S, Abroun S, Mehdizadeh M, Saiedi S, Maali A, Ghaffari S, Azad M. Various Signaling Pathways in Multiple Myeloma Cells and Effects of Treatment on These Pathways. CLINICAL LYMPHOMA MYELOMA & LEUKEMIA 2018; 18:311-320. [PMID: 29606369 DOI: 10.1016/j.clml.2018.03.007] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2017] [Revised: 03/05/2018] [Accepted: 03/14/2018] [Indexed: 12/22/2022]
Abstract
Multiple myeloma (MM) results from malignancy in plasma cells and occurs at ages > 50 years. MM is the second most common hematologic malignancy after non-Hodgkin lymphoma, which constitutes 1% of all malignancies. Despite the great advances in the discovery of useful drugs for this disease such as dexamethasone and bortezomib, it is still an incurable malignancy owing to the development of drug resistance. The tumor cells develop resistance to apoptosis, resulting in greater cell survival, and, ultimately, develop drug resistance by changing the various signaling pathways involved in cell proliferation, survival, differentiation, and apoptosis. We have reviewed the different signaling pathways in MM cells. We reached the conclusion that the most important factor in the drug resistance in MM patients is caused by the bone marrow microenvironment with production of adhesion molecules and cytokines. Binding of tumor cells to stromal cells prompts cytokine production of stromal cells and launches various signaling pathways such as Janus-activated kinase/signal transduction and activator of transcription, Ras/Raf/MEK/mitogen-activated protein kinase, phosphatidyl inositol 3-kinase/AKT, and NF-KB, which ultimately lead to the high survival rate and drug resistance in tumor cells. Thus, combining various drugs such as bortezomib, dexamethasone, lenalidomide, and melphalan with compounds that are not common, including CTY387, LLL-12, OPB31121, CNTO328, OSI-906, FTY720, triptolide, and AV-65, could be one of the most effective treatments for these patients.
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Affiliation(s)
- Ali Dehghanifard
- Department of Hematology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Saeid Kaviani
- Department of Hematology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Saeid Abroun
- Department of Hematology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | | | - Sajedeh Saiedi
- Health Research Institute, Research Center of Thalassemia and Hemoglobinopathy, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Amirhosein Maali
- Department of Medical Laboratory Sciences, Faculty of Allied Medicine, Qazvin University of Medical Sciences, Qazvin, Iran
| | - Sasan Ghaffari
- Department of Hematology, Faculty of Allied Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Mehdi Azad
- Department of Medical Laboratory Sciences, Faculty of Allied Medicine, Qazvin University of Medical Sciences, Qazvin, Iran.
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The CDK subunit CKS2 counteracts CKS1 to control cyclin A/CDK2 activity in maintaining replicative fidelity and neurodevelopment. Dev Cell 2012; 23:356-70. [PMID: 22898779 PMCID: PMC3898080 DOI: 10.1016/j.devcel.2012.06.018] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2011] [Revised: 05/16/2012] [Accepted: 06/28/2012] [Indexed: 01/09/2023]
Abstract
CKS proteins are evolutionarily conserved cyclin-dependent kinase (CDK) subunits whose functions are incompletely understood. Mammals have two CKS proteins. CKS1 acts as a cofactor to the ubiquitin ligase complex SCFSKP2 to promote degradation of CDK inhibitors, such as p27. Little is known about the role of the closely related CKS2. Using a Cks2−/− knockout mouse model, we show that CKS2 counteracts CKS1 and stabilizes p27. Unopposed CKS1 activity in Cks2−/− cells leads to loss of p27. The resulting unrestricted cyclin A/CDK2 activity is accompanied by shortening of the cell cycle, increased replication fork velocity, and DNA damage. In vivo, Cks2−/− cortical progenitor cells are limited in their capacity to differentiate into mature neurons, a phenotype akin to animals lacking p27. We propose that the balance between CKS2 and CKS1 modulates p27 degradation, and with it cyclin A/CDK2 activity, to safeguard replicative fidelity and control neuronal differentiation.
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Shi L, Wang S, Zangari M, Xu H, Cao TM, Xu C, Wu Y, Xiao F, Liu Y, Yang Y, Salama M, Li G, Tricot G, Zhan F. Over-expression of CKS1B activates both MEK/ERK and JAK/STAT3 signaling pathways and promotes myeloma cell drug-resistance. Oncotarget 2011; 1:22-33. [PMID: 20930946 PMCID: PMC2949973 DOI: 10.18632/oncotarget.105] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Here we demonstrate the crucial role of CKS1B in multiple myeloma (MM) progression and define CKS1B-mediated SKP2/p27Kip1-independent down-stream signaling pathways. Forced-expression of CKS1B in MM cells increased cell multidrug-resistance. CKS1B activates STAT3 and MEK/ERK pathways. In contrast, SKP2 knockdown or p27Kip1 over-expression resulted in activation of the STAT3 and MEK/ERK pathways. Further investigations showed that BCL2 is a downstream target of MEK/ERK signaling. Stimulation of STAT3 and MEK/ERK signaling pathways partially abrogated CKS1B knockdown induced MM cell death and growth inhibition. Targeting STAT3 and MEK/ ERK signaling pathways by specific inhibitors induced significant MM cell death and growth inhibition in CKS1B-overexpressing MM cells and their combinations resulted in synergy. Thus, our findings provide a rationale for targeting STAT3 and MEK/ERK/ BCL2 signaling in aggressive CKS1B-overexpressing MM.
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Affiliation(s)
- Lei Shi
- Division of Hematology/BMT/myeloma Program, University of Utah School of Medicine, Salt Lake City, Utah 84132, USA
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Chang H, Trieu Y, Qi X, Jiang NN, Xu W, Reece D. Impact of cytogenetics in patients with relapsed or refractory multiple myeloma treated with bortezomib: Adverse effect of 1q21 gains. Leuk Res 2010; 35:95-8. [PMID: 20537706 DOI: 10.1016/j.leukres.2010.05.002] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2010] [Revised: 04/08/2010] [Accepted: 05/01/2010] [Indexed: 11/25/2022]
Abstract
We investigated the influence of genetic risk factors on the clinical response to bortezomib in 85 relapsed/refractory multiple myeloma (MM) patients. Interphase cytoplasmic fluorescence in situ hybridization (cIg-FISH) detected del(13q), del(17p), del(1p21), t(4;14), and 1q21 gain in 38%, 22%, 26%, 18% and 39% of evaluable cases. Forty-nine patients (49%) responded to bortezomib with median progression free (PFS) and overall survivals (OS) of 5.0 and 12.6 months, respectively. Patients with 1q21 gain had a significantly shorter OS (5.3 months vs. 24.6 months, p=0.0006) and PFS (2.3 months vs. 7.3 months, p=0.003) than patients without such abnormality. There was no significant difference in response rate, response duration, PFS or OS for any of the other genetic risk factors tested. Multivariate analysis confirmed that 1q21 gain is an independent risk factor for PFS (p=0.03) and OS (p=0.009) of bortezomib-treated relapsed/refractory myeloma.
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Affiliation(s)
- Hong Chang
- Department of Laboratory Hematology, University Health Network, University of Toronto, Toronto, Canada.
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Huang CW, Lin CY, Huang HY, Liu HW, Chen YJ, Shih DF, Chen HY, Juan CC, Ker CG, Huang CYF, Li CF, Shiue YL. CKS1B overexpression implicates clinical aggressiveness of hepatocellular carcinomas but not p27(Kip1) protein turnover: an independent prognosticator with potential p27 (Kip1)-independent oncogenic attributes? Ann Surg Oncol 2009; 17:907-22. [PMID: 19866239 DOI: 10.1245/s10434-009-0779-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2009] [Indexed: 12/25/2022]
Abstract
BACKGROUND Through data mining the Stanford Microarray Database, the CKS1B transcript was found to be frequently upregulated in hepatocellular carcinomas (HCCs) with low alpha-fetal protein (AFP) expression. Together with SKP2, CKS1B is known to implicate p27(Kip1) protein turnover promoting cell-cycle progression. METHODS CKS1B, p27(Kip1), and SKP2 were immunostained in 75 HCCs and correlated with clinicopathological features, local recurrence-free survival (LRFS), and overall survival (OS). Silencing of CKS1B and SKP2 with interference short-hairpin RNA (shRNA) was performed in SK-Hep1 and Hep-3B cell lines. RESULTS Immunohistochemically, increased CKS1B and SKP2, and attenuated p27(Kip1) were all associated with tumor multiplicity (P < 0.05) and increasing American Joint Committee on Cancer (AJCC) stage (P < 0.05). Overexpression of CKS1B significantly correlated with advanced Okuda stages (P = 0.048) and SKP2 overexpression (P = 0.047). Neither CKS1B nor SKP2 was inversely related to p27(Kip1), which was reinforced by no alteration in p27(Kip1) abundance in HCC-derived cells with CKS1B or SKP2 silencing. Both CKS1B overexpression (P = 0.0011 and P = 0.0017) and p27(Kip1) attenuation (P = 0.0079 and P = 0.0085) were predictive of OS and LRFS, respectively, while SKP2 overexpression was associated with worse OS alone (P = 0.0043). Combined assessment of CKS1B and p27(Kip1) was able to robustly distinguish three prognostically different groups (P < 0.0001). In multivariate comparison, CKS1B overexpression represented the strongest independent adverse prognosticator [OS, P = 0.0235, hazard ratio (HR): 4.193; LRFS, P = 0.0204, HR: 4.262], followed by p27(Kip1) attenuation (OS, P = 0.0320, HR: 2.553; LRFS, P = 0.0262, HR: 2.533). CONCLUSIONS CKS1B protein overexpression in HCCs is implicated in clinical aggressiveness but not in p27(Kip1) turnover, implying presence of p27(Kip1)-independent oncogenic attributes. The combined assessment of CKS1B and p27(Kip1) immunoexpressions effectively risk-stratifies HCCs with different prognoses, which may aid in the management of this deadly malignancy.
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Affiliation(s)
- Ching-Wen Huang
- Department of Surgery, Yuan's General Hospital, Kaohsiung, Taiwan
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Counter-regulation by atorvastatin of gene modulations induced by L-NAME hypertension is associated with vascular protection. Vascul Pharmacol 2009; 51:253-61. [DOI: 10.1016/j.vph.2009.06.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2008] [Revised: 05/14/2009] [Accepted: 06/25/2009] [Indexed: 11/23/2022]
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12
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Roy S, Jeffrey R, Tenniswood M. Array-based analysis of the effects of trichostatin A and CG-1521 on cell cycle and cell death in LNCaP prostate cancer cells. Mol Cancer Ther 2008; 7:1931-9. [DOI: 10.1158/1535-7163.mct-07-2353] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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13
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Upregulation of topoisomerase IIalpha expression in advanced gallbladder carcinoma: a potential chemotherapeutic target. J Cancer Res Clin Oncol 2008; 134:793-801. [PMID: 18204862 DOI: 10.1007/s00432-007-0348-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2007] [Accepted: 12/10/2007] [Indexed: 12/16/2022]
Abstract
PURPOSE The lack of treatment options other than surgical resection results in unfavourable prognosis of advanced gallbladder carcinoma. The aim of this study was to identify cancer-specific cellular targets that would form the basis for some therapeutic approaches for this disease. METHODS Twelve advanced gallbladder carcinoma tissue samples and three samples of normal gallbladder epithelium were screened to identify differentially expressed genes by DNA microarray analysis. The results obtained were validated in an independent sample set by quantitative real-time reverse transcription-polymerase chain reaction (RT-PCR). Among the genes picked-up, one molecule, topoisomerase IIalpha (TOPO IIalpha), was further assessed immunohistochemically as a potential chemotherapeutic target, and the growth inhibitory effects of etoposide, doxorubicin and idarubicin, representative TOPO IIalpha inhibitors, on two different gallbladder carcinoma cell lines were compared with that of gemcitabine and 5-fulorouracil. RESULTS Five upregulated genes were identified: four cell cycle-related genes (TOPO IIalpha, cyclin B2, CDC28 protein kinase regulatory subunit 2, ubiquitin-conjugating enzyme E2C) and a metabolism-related gene (gamma-glutamyl hydrolase). Immunohistochemically, TOPO IIalpha was expressed in gallbladder cancer cells, and 16 of 35 cases (46%) had strong TOPO IIalpha expression defined as having a labeling index of >50%. In in vitro growth inhibition assay, etoposide, as well as doxorubicin and idarubicin, was the most effective for OCUG-1 cells that had strong TOPO IIalpha expression, while gemicitabine was the most effective for NOZ cells with weak TOPO IIalpha expression. Etoposide induced apoptosis of OCUG-1 cells. CONCLUSIONS TOPO IIalpha might be an effective chemotherapeutic target in advanced gallbladder carcinoma, especially when it is expressed strongly.
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Zhan F, Colla S, Wu X, Chen B, Stewart JP, Kuehl WM, Barlogie B, Shaughnessy JD. CKS1B, overexpressed in aggressive disease, regulates multiple myeloma growth and survival through SKP2- and p27Kip1-dependent and -independent mechanisms. Blood 2007; 109:4995-5001. [PMID: 17303695 PMCID: PMC1885527 DOI: 10.1182/blood-2006-07-038703] [Citation(s) in RCA: 117] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Overexpression of CKS1B, a gene mapping within a minimally amplified region between 153 to 154 Mb of chromosome 1q21, is linked to a poor prognosis in multiple myeloma (MM). CKS1B binds to and activates cyclin-dependent kinases and also interacts with SKP2 to promote the ubiquitination and proteasomal degradation of p27(Kip1). Overexpression of CKS1B or SKP2 contributes to increased p27(Kip1) turnover, cell proliferation, and a poor prognosis in many tumor types. Using 4 MM cell lines harboring MAF-, FGFR3/MMSET-, or CCND1-activating translocations, we show that lentiviral delivery of shRNA directed against CKS1B resulted in ablation of CKS1B mRNA and protein with concomitant stabilization of p27(Kip1), cell cycle arrest, and apoptosis. Although shRNA-mediated knockdown of SKP2 and forced expression of a nondegradable form of p27(Kip1) (p27(T187A)) led to cell cycle arrest, apoptosis was modest. Of importance, while knockdown of SKP2 or overexpression of p27(T187A) induced cell cycle arrest in KMS28PE, an MM cell line with biallelic deletion of CDKN1B/p27(Kip1), CKS1B ablation induced strong apoptosis. These data suggest that CKS1B influences myeloma cell growth and survival through SKP2- and p27(Kip1)-dependent and -independent mechanisms and that therapeutic strategies aimed at abolishing CKS1B function may hold promise for the treatment of high-risk disease for which effective therapies are currently lacking.
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Affiliation(s)
- Fenghuang Zhan
- Donna D and Donald M. Lambert Laboratory of Myeloma Genetics at the Myeloma Institute for Research and Therapy, University of Arkansas for Medical Sciences, 4301 W. Markham Street, Little Rock, AR 72205, USA.
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15
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Traka M, Gasper AV, Smith JA, Hawkey CJ, Bao Y, Mithen RF. Transcriptome analysis of human colon Caco-2 cells exposed to sulforaphane. J Nutr 2005; 135:1865-72. [PMID: 16046710 DOI: 10.1093/jn/135.8.1865] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Sulforaphane (SF), a dietary phytochemical obtained from broccoli, has been implicated in several physiological processes consistent with anticarcinogenic activity, including enhanced xenobiotic metabolism, cell cycle arrest, and apoptosis. In this study, we report changes in global gene expression in Caco-2 cells exposed to physiologically appropriate concentrations of SF, through the use of replicated Affymetrix array and RT-PCR experiments. After exposure to 50 micromol/L SF, 106 genes exhibited a >2-fold increase in expression and 63 genes exhibited a >2-fold decrease in expression. There were fewer changes in gene expression at lower SF concentrations. The majority of these genes had not previously been shown to be modulated by SF, suggesting novel mechanisms of possible anticarcinogenic activity, including induction of differentiation and modulation of fatty acid metabolism. The changes in the expression of 10 of these genes, together with 4 additional genes of biological interest, were further quantified in independent studies with RT-PCR. These genes include several that have recently become associated with carcinogenesis, such as Krüppel-like factor (KLF)4, a gut-enriched transcription factor associated with induction of differentiation and reduction in cellular proliferation; DNA (cytosine-5-)-methyltransferase 1, associated with methylation; and alpha-methylacyl-CoA racemase (AMACR), a marker associated with the development of colon and prostate cancer. The expression of 5 of these genes [caudal type homeo box transcription factor 2 (CDX-2), KLF4, KLF5, cyclin-dependent kinase inhibitor 1A (p21), and AMACR] was additionally studied after in vitro exposure to SF of surgically resected healthy and cancerous colon tissue from each of 3 patients. The study suggests the complex effects that SF has on gene expression and highlights several potential mechanisms by which the consumption of broccoli may reduce the risk of carcinogenesis.
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Affiliation(s)
- Maria Traka
- Nutrition Division, Institute of Food Research, Norwich, UK
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16
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Lemaître G, Lamartine J, Pitaval A, Vaigot P, Garin J, Bouet S, Petat C, Soularue P, Gidrol X, Martin MT, Waksman G. Expression profiling of genes and proteins in HaCaT keratinocytes: Proliferating versus differentiated state. J Cell Biochem 2004; 93:1048-62. [PMID: 15389883 DOI: 10.1002/jcb.20212] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The knowledge of the mechanism of keratinocyte differentiation in culture is still uncompleted. The emergence of new technologies, such as cDNA microarrays or 2D electrophoresis followed by mass spectrometry analysis, has allowed the identification of genes and proteins expressed in biological processes in keratinocytes. Here, we report a genome wide analysis of proliferating versus differentiated human HaCaT keratinocytes. We found that genes and proteins which take part in the cell cycle control, carbohydrate metabolism, cell auto-immunity, adhesion and cytokine signal transduction pathways were regulated in differentiated HaCaT keratinocytes. In addition, we identified seven proteins and 33 transcripts that had not been previously described as differentially expressed in proliferating versus differentiated HaCaT cells. Furthermore, some of these transcripts or proteins were similarly regulated in human primary keratinocytes and in human epidermis. The present study opens new areas of investigation in the comprehension of keratinocyte differentiation.
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Affiliation(s)
- Gilles Lemaître
- Service de Génomique Fonctionnelle, CEA, Département de Radiobiologie et Radiopathologie, Evry, France
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17
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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: 45] [Impact Index Per Article: 2.0] [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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18
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Vogel L, Baratte B, Détivaud L, Azzi L, Leopold P, Meijer L. Molecular cloning and characterisation of p15(CDK-BP), a novel CDK-binding protein. BIOCHIMICA ET BIOPHYSICA ACTA 2002; 1589:219-31. [PMID: 12007796 DOI: 10.1016/s0167-4889(02)00175-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
The suc1/Cks proteins are well-conserved regulatory components of cyclin-dependent kinases 1 and 2 (CDK1/2). These small molecular mass proteins form a stable complex with CDK1/2 and are essential for normal regulation of CDKs during the cell division cycle and for degradation of p27(kip1). Despite the high degree of homology between the nine known CDKs, only CDK1, CDK2 and, to a lesser extent, CDK3 are able to bind to the suc1/Cks proteins. No additional suc1/Cks-related proteins interacting with other CDKs have been reported. We have purified, from starfish oocytes, a 15 kDa protein, p15(CDK-BP), which cross-reacts with anti-Cks antibodies (L. Azzi, L. Meijer, A.C. Ostvold, J. Lew, J.H. Wang, J. Biol. Chem. 269 (1994)). Following microsequencing of internal peptides and generation of corresponding oligonucleotides we cloned two cDNAs encoding two closely related proteins, p15A and p15B. The predicted protein sequences display distant but distinct homology with the Suc1/Cks proteins, including the genuine starfish Cks homologue protein, p9(CksMg). P15 transcripts are essentially expressed in oocytes. Recombinant p15B or native p15(CDK-BP) bind a 34 kDa protein cross-reacting with anti-PSTAIRE antibodies, a feature characteristic of CDK-related proteins. In addition p15B interacts tightly with CDK4, CDK6, CDK8 and the yeast CDC28-related kinase Pho85, but not with CDK1, CDK2 or CDK7. P15 does not appear to alter the catalytic activity of the bound kinases.
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Affiliation(s)
- Lee Vogel
- CNRS, Station Biologique, Roscoff, Bretagne, France
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19
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Ceccarelli E, Mann C. A Cdc28 mutant uncouples G1 cyclin phosphorylation and ubiquitination from G1 cyclin proteolysis. J Biol Chem 2001; 276:41725-32. [PMID: 11527976 DOI: 10.1074/jbc.m107087200] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Proteolysis of the yeast G(1) cyclins is triggered by their Cdc28-dependent phosphorylation. Phosphorylated Cln1 and Cln2 are ubiquitinated by the SCF-Grr1 complex and then degraded by the 26 S proteasome. In this study, we identified a cak1 allele in a genetic screen for mutants that stabilize the yeast G(1) cyclins. Further characterization showed that Cln2HA was hypophosphorylated, unable to bind Cdc28, and stabilized in cak1 mutants at the restrictive temperature. Hypophosphorylation of Cln2HA could thus explain its stabilization. To test this possibility, we expressed a Cak1-independent mutant of Cdc28 (Cdc28-43244) in cak1 mutants and found that Cln2HA phosphorylation was restored, but surprisingly, the phospho-Cln2HA was stabilized. When bound to Cdc28-43244, Cln2HA was recognized and polyubiquitinated by SCF-Grr1. The Cdc28-43244 mutant thus reveals an unexpected complexity in the degradation of polyubiquitinated Cln2HA by the proteasome.
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Affiliation(s)
- E Ceccarelli
- Service de Biochimie et de Génétique Moléculaire, CEA/Saclay, F-91191 Gif-sur-Yvette, Cedex, France
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20
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Landrieu I, Odaert B, Wieruszeski JM, Drobecq H, Rousselot-Pailley P, Inze D, Lippens G. p13(SUC1) and the WW domain of PIN1 bind to the same phosphothreonine-proline epitope. J Biol Chem 2001; 276:1434-8. [PMID: 11013245 DOI: 10.1074/jbc.m006420200] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The WW domain of the human PIN1 and p13(SUC1), a subunit of the cyclin-dependent kinase complex, were previously shown to be involved in the regulation of the cyclin-dependent kinase complex activity at the entry into mitosis, by an unresolved molecular mechanism. We report here experimental evidence for the direct interaction of p13(SUC1) with a model CDC25 peptide, dependent on the phosphorylation state of its threonine. Chemical shift perturbation of backbone (1)H(N), (15)N, and (13)Calpha resonances during NMR titration experiments allows accurate identification of the binding site, primarily localized around the anion-binding site, occupied in the crystal structure of the homologous p9(CKSHs2) by a sulfate molecule. The epitope recognized by p13(SUC1) includes the proline at position +1 of the phosphothreonine, as was shown by the decrease in affinity for a mutated CDC25 phosphopeptide, containing an alanine/proline substitution. No direct interaction between the PIN1 WW domain or its catalytic proline cis/trans-isomerase domain and p13(SUC1) was detected, but our study showed that in vitro the WW domain of the human PIN1 antagonizes the binding of the p13(SUC1) to the CDC25 phosphopeptide, by binding to the same phosphoepitope. We thus propose that the full cyclin-dependent kinase complex stimulates the phosphorylation of CDC25 through binding of its p13(SUC1) module to the phosphoepitope of the substrate and that the reported WW antagonism of p13(SUC1)-stimulated CDC25 phosphorylation is caused by competitive binding of both protein modules to the same phosphoepitope.
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Affiliation(s)
- I Landrieu
- CNRS UMR 8525, Institut de Biologie de Lille/Pasteur Institute of Lille, 59019 Lille Cedex, France.
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21
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Kaldis P, Cheng A, Solomon MJ. The effects of changing the site of activating phosphorylation in CDK2 from threonine to serine. J Biol Chem 2000; 275:32578-84. [PMID: 10931829 DOI: 10.1074/jbc.m003212200] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cyclin-dependent kinases (CDKs) that control cell cycle progression are regulated in many ways, including activating phosphorylation of a conserved threonine residue. This essential phosphorylation is carried out by the CDK-activating kinase (CAK). Here we examine the effects of replacing this threonine residue in human CDK2 by serine. We found that cyclin A bound equally well to wild-type CDK2 (CDK2(Thr-160)) or to the mutant CDK2 (CDK2(Ser-160)). In the absence of activating phosphorylation, CDK2(Ser-160)-cyclin A complexes were more active than wild-type CDK2(Thr-160)-cyclin A complexes. In contrast, following activating phosphorylation, CDK2(Ser-160)-cyclin A complexes were less active than phosphorylated CDK2(Thr-160)-cyclin A complexes, reflecting a much smaller effect of activating phosphorylation on CDK2(Ser-160). The kinetic parameters for phosphorylating histone H1 were similar for mutant and wild-type CDK2, ruling out a general defect in catalytic activity. Interestingly, the CDK2(Ser-160) mutant was selectively defective in phosphorylating a peptide derived from the C-terminal domain of RNA polymerase II. CDK2(Ser-160) was efficiently phosphorylated by CAKs, both human p40(MO15)(CDK7)-cyclin H and budding yeast Cak1p. In fact, the k(cat) values for phosphorylation of CDK2(Ser-160) were significantly higher than for phosphorylation of CDK2(Thr-160), indicating that CDK2(Ser-160) is actually phosphorylated more efficiently than wild-type CDK2. In contrast, dephosphorylation proceeded more slowly with CDK2(Ser-160) than with wild-type CDK2, either in HeLa cell extract or by purified PP2Cbeta. Combined with the more efficient phosphorylation of CDK2(Ser-160) by CAK, we suggest that one reason for the conservation of threonine as the site of activating phosphorylation may be to favor unphosphorylated CDKs following the degradation of cyclins.
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Affiliation(s)
- P Kaldis
- Yale University School of Medicine, Department of Molecular Biophysics and Biochemistry, New Haven, Connecticut 06520-8114, USA.
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22
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Reynard GJ, Reynolds W, Verma R, Deshaies RJ. Cks1 is required for G(1) cyclin-cyclin-dependent kinase activity in budding yeast. Mol Cell Biol 2000; 20:5858-64. [PMID: 10913169 PMCID: PMC86063 DOI: 10.1128/mcb.20.16.5858-5864.2000] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
p13(suc1) (Cks) proteins have been implicated in the regulation of cyclin-dependent kinase (CDK) activity. However, the mechanism by which Cks influences the function of cyclin-CDK complexes has remained elusive. We show here that Cks1 is required for the protein kinase activity of budding yeast G(1) cyclin-CDK complexes. Cln2 and Cdc28 subunits coexpressed in baculovirus-infected insect cells fail to exhibit protein kinase activity towards multiple substrates in the absence of Cks1. Cks1 can both stabilize Cln2-Cdc28 complexes and activate intact complexes in vitro, suggesting that it plays multiple roles in the biogenesis of active G(1) cyclin-CDK complexes. In contrast, Cdc28 forms stable, active complexes with the B-type cyclins Clb4 and Clb5 regardless of whether Cks1 is present. The levels of Cln2-Cdc28 and Cln3-Cdc28 protein kinase activity are severely reduced in cks1-38 cell extracts. Moreover, phosphorylation of G(1) cyclins, which depends on Cdc28 activity, is reduced in cks1-38 cells. The role of Cks1 in promoting G(1) cyclin-CDK protein kinase activity both in vitro and in vivo provides a simple molecular rationale for the essential role of CKS1 in progression through G(1) phase in budding yeast.
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Affiliation(s)
- G J Reynard
- Division of Biology, California Institute of Technology, Pasadena, California 91125, USA
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23
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Abstract
The cdk-activating kinase (CAK) activates cyclin-dependent kinases (cdks) that control cell-cycle progression by phosphorylating a threonine residue conserved in cdks. CAK from humans contains p40MO15 (cdk7), cyclin H and MAT1, which are also subunits of transcription factor IIH where they phosphorylate the C-terminal domain of the large subunit of RNA polymerase II. In contrast, budding yeast Cak1p is a monomeric enzyme without C-terminal domain kinase activity. Here, we analyze CAK activities in HeLa cells using cdk2-affinity chromatography. In addition to MO15, a second CAK activity was detected that runs on gel filtration at 30-40 kDa. This activity phosphorylated and activated cdk2 and cdk6. Furthermore, this 'small CAK' activity resembled Cak1p rather than MO15 in terms of substrate specificity, reactivity to antibodies against MO15 and Cak1p, and sensitivity to 5'-fluorosulfonylbenzoyladenosine, an irreversible inhibitory ATP analog. Our findings suggest the presence of at least two different CAK activities in human cells.
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Affiliation(s)
- P Kaldis
- Yale University School of Medicine, New Haven, USA
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24
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Palmer A, Nebreda AR. The activation of MAP kinase and p34cdc2/cyclin B during the meiotic maturation of Xenopus oocytes. PROGRESS IN CELL CYCLE RESEARCH 2000; 4:131-43. [PMID: 10740821 DOI: 10.1007/978-1-4615-4253-7_12] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
G2-arrested Xenopus oocytes are induced to enter M-phase of meiosis by progesterone stimulation. This process, known as meiotic maturation, requires the activation of p34cdc2/cyclin B complexes (pre-MPF) which is brought about by the prior translation of specific maternal mRNAs stored in the oocyte. One of these mRNAs encodes for the protein kinase Mos which has an essential role in oocyte maturation, most likely due to its ability to activate MAP kinase (MAPK). Here we review our current knowledge on the Mos/MAPK signalling pathway and a recently found connection between MAPK-activated p90rsk and the p34cdc2 inhibitory kinase Myt1. We also discuss a pathway that involves the protein kinase Plx1 and leads to the activation of the phosphatase Cdc25, as well as other regulators of p34cdc2/cyclin B activity which may have a role in oocyte maturation.
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Affiliation(s)
- A Palmer
- European Molecular Biology Laboratory, Heidelberg, Germany
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25
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Détivaud L, Pettit GR, Meijer L. Characterization of a novel cdk1-related kinase. EUROPEAN JOURNAL OF BIOCHEMISTRY 1999; 264:55-66. [PMID: 10447673 DOI: 10.1046/j.1432-1327.1999.00576.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The p13suc1/p9CKShs proteins bind tightly to the cyclin-dependent kinases cdk1 and cdk2. The distantly related protein, p15cdk-BP, binds cdk4/6, cdk5 and cdk8. We now show that immobilized p15cdk-BP binds both an HMG-I kinase and a 35-kDa protein that cross-reacts with anti-PSTAIRE antibodies (PSTAIRE is a totally conserved motif located in subdomain III of cdk). This 'cdkX' and the HMG-I kinase also bind to an immobilized inhibitor of cdks (HD). Several properties clearly distinguish cdkX, and its associated HMG-I kinase, from known anti-PSTAIRE cross-reactive cdks: (a) cdkX migrates, in SDS/PAGE, in a position intermediate between prophase phosphorylated cdk1 and metaphase dephosphorylated cdk1; (b) in contrast with cdk1, cdkX and associated HMG-I kinase activity do not decrease following successive depletions on p9CKShs1-sepharose; (c) cdkX and associated HMG-I kinase activity, but not cdk1, decrease following depletions on immobilized inhibitor; (d) cdkX is expressed during the early development of sea urchin embryos; in contrast with cdk1/cyclin B kinase, the p15cdk-BP-bound HMG-I kinase is active throughout the cell cycle; compared with cdk1 it is active later in development; (e) p15cdk-BP-bound HMG-I kinase is essentially insensitive to powerful inhibitors of cdk such as purvalanol, roscovitine, olomoucine, p21cip1 and p16INK4A; HD is only moderately inhibitory. Altogether these results suggest the existence of a new cdk1-related kinase, possibly involved in the regulation of early development. The presence of this kinase in all organisms investigated so far, from plants to mammals, calls for its definitive identification.
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Affiliation(s)
- L Détivaud
- CNRS, Station Biologique, Roscoff, France
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26
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Urbanowicz-Kachnowicz I, Baghdassarian N, Nakache C, Gracia D, Mekki Y, Bryon PA, Ffrench M. ckshs expression is linked to cell proliferation in normal and malignant human lymphoid cells. Int J Cancer 1999; 82:98-104. [PMID: 10360827 DOI: 10.1002/(sici)1097-0215(19990702)82:1<98::aid-ijc17>3.0.co;2-a] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Cyclin kinase sub-units (CKS) are known to interact with cyclin-dependent kinases (CDKs), but their functions are not completely understood and their expression in human tissues is not documented. For analyzing relationships of CKS with cell proliferation and/or with differentiation, we investigated the expression of ckshs1 and ckshs2 in normal and malignant human lymphoid cells. ckshs1 and ckshs2 expression appeared to be related to cell proliferation: (i) mRNAs increased with stimulation of normal peripheral-blood lymphocytes, and from the G1 to the SG2M phase in elutriated cells; (ii) P9 proteins were also induced by lymphocyte stimulation and were localized in nucleus where phosphorylated forms of CDK1 were also found; (iii) in vitro, the phosphorylated forms of CDK1 and CDK2 were preferentially linked to CKS. Among 45 patients presenting acute or chronic lymphoid malignancy, ckshs1 and ckshs2 mRNAs varied in a similar way and were significantly correlated to cell proliferation (p < 0.0001). When analysis was restricted solely to acute lymphoblastic leukemia (ALL) this correlation was still found and ckshs1 and ckshs2 were significantly more expressed in T-cell ALL than in B-cell-lineage ALL. These results confirm relationships between ckshs expression and cell proliferation, and pose the question of a link with cell differentiation.
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