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Kasturirangan S, Nancarrow DJ, Shah A, Lagisetty KH, Lawrence TS, Beer DG, Ray D. Isoform alterations in the ubiquitination machinery impacting gastrointestinal malignancies. Cell Death Dis 2024; 15:194. [PMID: 38453895 PMCID: PMC10920915 DOI: 10.1038/s41419-024-06575-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 02/19/2024] [Accepted: 02/23/2024] [Indexed: 03/09/2024]
Abstract
The advancement of RNAseq and isoform-specific expression platforms has led to the understanding that isoform changes can alter molecular signaling to promote tumorigenesis. An active area in cancer research is uncovering the roles of ubiquitination on spliceosome assembly contributing to transcript diversity and expression of alternative isoforms. However, the effects of isoform changes on functionality of ubiquitination machineries (E1, E2, E3, E4, and deubiquitinating (DUB) enzymes) influencing onco- and tumor suppressor protein stabilities is currently understudied. Characterizing these changes could be instrumental in improving cancer outcomes via the identification of novel biomarkers and targetable signaling pathways. In this review, we focus on highlighting reported examples of direct, protein-coded isoform variation of ubiquitination enzymes influencing cancer development and progression in gastrointestinal (GI) malignancies. We have used a semi-automated system for identifying relevant literature and applied established systems for isoform categorization and functional classification to help structure literature findings. The results are a comprehensive snapshot of known isoform changes that are significant to GI cancers, and a framework for readers to use to address isoform variation in their own research. One of the key findings is the potential influence that isoforms of the ubiquitination machinery have on oncoprotein stability.
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Affiliation(s)
| | - Derek J Nancarrow
- Surgery - Section of Thoracic Surgery, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Ayush Shah
- Departments of Radiation Oncology, University of Michigan, Ann Arbor, MI, 48109, USA
- Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, USA
| | - Kiran H Lagisetty
- Surgery - Section of Thoracic Surgery, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Theodore S Lawrence
- Departments of Radiation Oncology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - David G Beer
- Surgery - Section of Thoracic Surgery, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Dipankar Ray
- Departments of Radiation Oncology, University of Michigan, Ann Arbor, MI, 48109, USA.
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2
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Insufficiency of FZR1 disturbs HSC quiescence by inhibiting ubiquitin-dependent degradation of RUNX1 in aplastic anemia. Leukemia 2021; 36:834-846. [PMID: 34635784 DOI: 10.1038/s41375-021-01445-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 09/19/2021] [Accepted: 09/29/2021] [Indexed: 11/08/2022]
Abstract
FZR1 has been implicated as a master regulator of the cell cycle and quiescence, but its roles and molecular mechanisms in the pathogenesis of severe aplastic anemia (SAA) are unclear. Here, we report that FZR1 is downregulated in SAA HSCs compared with healthy control and is associated with decreased quiescence of HSC. Haploinsufficiency of Fzr1 shows impaired quiescence and self-renewal ability of HSC in two Fzr1 heterozygous knockout mouse models. Mechanistically, FZR1 insufficiency inhibits the ubiquitination of RUNX1 protein at lysine 125, leading to the accumulation of RUNX1 protein, which disturbs the quiescence of HSCs in SAA patients. Moreover, downregulation of Runx1 reversed the loss of quiescence and impaired long-term self-renew ability in Fzr1+/- HSCs in vivo and impaired repopulation capacity in BM from SAA patients in vitro. Our findings, therefore, raise the possibility of a decisive role of the FZR1-RUNX1 pathway in the pathogenesis of SAA via deregulation of HSC quiescence.
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3
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Bansal S, Tiwari S. Mechanisms for the temporal regulation of substrate ubiquitination by the anaphase-promoting complex/cyclosome. Cell Div 2019; 14:14. [PMID: 31889987 PMCID: PMC6927175 DOI: 10.1186/s13008-019-0057-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Accepted: 12/04/2019] [Indexed: 12/16/2022] Open
Abstract
The anaphase-promoting complex/cyclosome (APC/C) is a multi-subunit, multifunctional ubiquitin ligase that controls the temporal degradation of numerous cell cycle regulatory proteins to direct the unidirectional cell cycle phases. Several different mechanisms contribute to ensure the correct order of substrate modification by the APC/C complex. Recent advances in biochemical, biophysical and structural studies of APC/C have provided a deep mechanistic insight into the working of this complex ubiquitin ligase. This complex displays remarkable conformational flexibility in response to various binding partners and post-translational modifications, which together regulate substrate selection and catalysis of APC/C. Apart from this, various features and modifications of the substrates also influence their recognition and affinity to APC/C complex. Ultimately, temporal degradation of substrates depends on the kind of ubiquitin modification received, the processivity of APC/C, and other extrinsic mechanisms. This review discusses our current understanding of various intrinsic and extrinsic mechanisms responsible for ‘substrate ordering’ by the APC/C complex.
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Affiliation(s)
- Shivangee Bansal
- School of Biotechnology, Jawaharlal Nehru University, New Delhi, 110067 India
| | - Swati Tiwari
- School of Biotechnology, Jawaharlal Nehru University, New Delhi, 110067 India
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4
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Fan Y, Sanyal S, Bruzzone R. Breaking Bad: How Viruses Subvert the Cell Cycle. Front Cell Infect Microbiol 2018; 8:396. [PMID: 30510918 PMCID: PMC6252338 DOI: 10.3389/fcimb.2018.00396] [Citation(s) in RCA: 88] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Accepted: 10/22/2018] [Indexed: 01/10/2023] Open
Abstract
Interactions between the host and viruses during the course of their co-evolution have not only shaped cellular function and the immune system, but also the counter measures employed by viruses. Relatively small genomes and high replication rates allow viruses to accumulate mutations and continuously present the host with new challenges. It is therefore, no surprise that they either escape detection or modulate host physiology, often by redirecting normal cellular pathways to their own advantage. Viruses utilize a diverse array of strategies and molecular targets to subvert host cellular processes, while evading detection. These include cell-cycle regulation, major histocompatibility complex-restricted antigen presentation, intracellular protein transport, apoptosis, cytokine-mediated signaling, and humoral immune responses. Moreover, viruses routinely manipulate the host cell cycle to create a favorable environment for replication, largely by deregulating cell cycle checkpoints. This review focuses on our current understanding of the molecular aspects of cell cycle regulation that are often targeted by viruses. Further study of their interactions should provide fundamental insights into cell cycle regulation and improve our ability to exploit these viruses.
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Affiliation(s)
- Ying Fan
- HKU-Pasteur Research Pole, LKS Faculty of Medicine, School of Public Health, The University of Hong Kong, Hong Kong, Hong Kong.,MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Sumana Sanyal
- HKU-Pasteur Research Pole, LKS Faculty of Medicine, School of Public Health, The University of Hong Kong, Hong Kong, Hong Kong.,LKS Faculty of Medicine, School of Biomedical Sciences, The University of Hong Kong, Hong Kong, Hong Kong
| | - Roberto Bruzzone
- HKU-Pasteur Research Pole, LKS Faculty of Medicine, School of Public Health, The University of Hong Kong, Hong Kong, Hong Kong.,Department of Cell Biology and Infection, Institut Pasteur, Paris, France
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5
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APC/C FZR-1 Controls SAS-5 Levels To Regulate Centrosome Duplication in Caenorhabditis elegans. G3-GENES GENOMES GENETICS 2017; 7:3937-3946. [PMID: 29030390 PMCID: PMC5714490 DOI: 10.1534/g3.117.300260] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
As the primary microtubule-organizing center, centrosomes play a key role in establishing mitotic bipolar spindles that secure correct transmission of genomic content. For the fidelity of cell division, centrosome number must be strictly controlled by duplicating only once per cell cycle. Proper levels of centrosome proteins are shown to be critical for normal centrosome number and function. Overexpressing core centrosome factors leads to extra centrosomes, while depleting these factors results in centrosome duplication failure. In this regard, protein turnover by the ubiquitin-proteasome system provides a vital mechanism for the regulation of centrosome protein levels. Here, we report that FZR-1, the Caenorhabditis elegans homolog of Cdh1/Hct1/Fzr, a coactivator of the anaphase promoting complex/cyclosome (APC/C), an E3 ubiquitin ligase, functions as a negative regulator of centrosome duplication in the C. elegans embryo. During mitotic cell division in the early embryo, FZR-1 is associated with centrosomes and enriched at nuclei. Loss of fzr-1 function restores centrosome duplication and embryonic viability to the hypomorphic zyg-1(it25) mutant, in part, through elevated levels of SAS-5 at centrosomes. Our data suggest that the APC/CFZR-1 regulates SAS-5 levels by directly recognizing the conserved KEN-box motif, contributing to proper centrosome duplication. Together, our work shows that FZR-1 plays a conserved role in regulating centrosome duplication in C. elegans.
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6
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Gupta A, Tsuchiya Y, Ohta M, Shiratsuchi G, Kitagawa D. NEK7 is required for G1 progression and procentriole formation. Mol Biol Cell 2017; 28:2123-2134. [PMID: 28539406 PMCID: PMC5509424 DOI: 10.1091/mbc.e16-09-0643] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Revised: 04/27/2017] [Accepted: 05/18/2017] [Indexed: 12/11/2022] Open
Abstract
As cells exit mitosis, the decision to commit to the next cell cycle is made during G1. Not only DNA replication, but also centriole duplication is initiated as cells enter the S-phase. The kinase NEK7 is required for the timely regulation of G1 progression, S-phase entry, and procentriole formation. The decision to commit to the cell cycle is made during G1 through the concerted action of various cyclin–CDK complexes. Not only DNA replication, but also centriole duplication is initiated as cells enter the S-phase. The NIMA-related kinase NEK7 is one of many factors required for proper centriole duplication, as well as for timely cell cycle progression. However, its specific roles in these events are poorly understood. In this study, we find that depletion of NEK7 inhibits progression through the G1 phase in human U2OS cells via down-regulation of various cyclins and CDKs and also inhibits the earliest stages of procentriole formation. Depletion of NEK7 also induces formation of primary cilia in human RPE1 cells, suggesting that NEK7 acts at least before the restriction point during G1. G1-arrested cells in the absence of NEK7 exhibit abnormal accumulation of the APC/C cofactor Cdh1 at the vicinity of centrioles. Furthermore, the ubiquitin ligase APC/CCdh1 continuously degrades the centriolar protein STIL in these cells, thus inhibiting centriole assembly. Collectively our results demonstrate that NEK7 is involved in the timely regulation of G1 progression, S-phase entry, and procentriole formation.
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Affiliation(s)
- Akshari Gupta
- Division of Centrosome Biology, Department of Molecular Genetics, National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan.,Department of Genetics, School of Life Science, Graduate University for Advanced Studies (SOKENDAI), Mishima, Shizuoka 411-8540, Japan
| | - Yuki Tsuchiya
- Division of Centrosome Biology, Department of Molecular Genetics, National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan.,Department of Genetics, School of Life Science, Graduate University for Advanced Studies (SOKENDAI), Mishima, Shizuoka 411-8540, Japan
| | - Midori Ohta
- Division of Centrosome Biology, Department of Molecular Genetics, National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan
| | - Gen Shiratsuchi
- Division of Centrosome Biology, Department of Molecular Genetics, National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan
| | - Daiju Kitagawa
- Division of Centrosome Biology, Department of Molecular Genetics, National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan .,Department of Genetics, School of Life Science, Graduate University for Advanced Studies (SOKENDAI), Mishima, Shizuoka 411-8540, Japan
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7
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Zhang M, Yao F, Luan H, Zhao W, Jing T, Zhang S, Hou L, Zou X. APC/C CDC20 and APC/C play pivotal roles in the process of embryonic development in Artemia sinica. Sci Rep 2016; 6:39047. [PMID: 27991546 PMCID: PMC5171921 DOI: 10.1038/srep39047] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Accepted: 11/17/2016] [Indexed: 11/09/2022] Open
Abstract
Anaphase Promoting Complex or Cyclosome (APC/C) is a representative E3 ubiquitin ligase, triggering the transition of metaphase to anaphase by regulating degradation and ensures the exit from mitosis. Cell division cycle 20 (CDC20) and Cell division cycle 20 related protein 1 (CDH1), as co-activators of APC/C, play significant roles in the spindle assembly checkpoint, guiding ubiquitin-mediated degradation, together with CDC23. During the embryonic development of the brine shrimp, Artemia sinica, CDC20, CDH1 and CDC23 participate in cell cycle regulation, but the specific mechanisms of their activities remain unknown. Herein, the full-length cDNAs of cdc20 and cdc23 from A. sinica were cloned. Real-time PCR analyzed the expression levels of As-cdc20 and As-cdc23. The locations of CDH1, CDC20 and CDC23 showed no tissue or organ specificity. Furthermore, western blotting showed that the levels of As-CDC20, securin, cyclin B, CDK1, CDH1, CDC14B, CDC23 and geminin proteins conformed to their complicated degradation relationships during different embryo stages. Our research revealed that As-CDC20, As-CDH1 and APC mediate the mitotic progression, downstream proteins degradation and cellular differentiation in the process of embryonic development in A. sinica.
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Affiliation(s)
- Mengchen Zhang
- College of Life Sciences, Liaoning Normal University, Dalian 116081, China
| | - Feng Yao
- College of Life Sciences, Liaoning Normal University, Dalian 116081, China
| | - Hong Luan
- College of Life Sciences, Liaoning Normal University, Dalian 116081, China
| | - Wei Zhao
- College of Life Sciences, Liaoning Normal University, Dalian 116081, China
| | - Ting Jing
- College of Life Sciences, Liaoning Normal University, Dalian 116081, China
| | - Shuang Zhang
- College of Life Sciences, Liaoning Normal University, Dalian 116081, China
| | - Lin Hou
- College of Life Sciences, Liaoning Normal University, Dalian 116081, China
| | - Xiangyang Zou
- Department of Biology, Dalian Medical University, Dalian 116044, China
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8
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Höckner S, Neumann-Arnold L, Seufert W. Dual control by Cdk1 phosphorylation of the budding yeast APC/C ubiquitin ligase activator Cdh1. Mol Biol Cell 2016; 27:2198-212. [PMID: 27226481 PMCID: PMC4945139 DOI: 10.1091/mbc.e15-11-0787] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Accepted: 05/18/2016] [Indexed: 12/15/2022] Open
Abstract
The antagonism between cyclin-dependent kinases (Cdks) and the ubiquitin ligase APC/C-Cdh1 is central to eukaryotic cell cycle control. APC/C-Cdh1 targets cyclin B and other regulatory proteins for degradation, whereas Cdks disable APC/C-Cdh1 through phosphorylation of the Cdh1 activator protein at multiple sites. Budding yeast Cdh1 carries nine Cdk phosphorylation sites in its N-terminal regulatory domain, most or all of which contribute to inhibition. However, the precise role of individual sites has remained unclear. Here, we report that the Cdk phosphorylation sites of yeast Cdh1 are organized into autonomous subgroups and act through separate mechanisms. Cdk sites 1-3 had no direct effect on the APC/C binding of Cdh1 but inactivated a bipartite nuclear localization sequence (NLS) and thereby controlled the partitioning of Cdh1 between cytoplasm and nucleus. In contrast, Cdk sites 4-9 did not influence the cell cycle-regulated localization of Cdh1 but prevented its binding to the APC/C. Cdk sites 4-9 reside near two recently identified APC/C interaction motifs in a pattern conserved with the human Cdh1 orthologue. Thus a Cdk-inhibited NLS goes along with Cdk-inhibited APC/C binding sites in yeast Cdh1 to relay the negative control by Cdk1 phosphorylation of the ubiquitin ligase APC/C-Cdh1.
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Affiliation(s)
- Sebastian Höckner
- Department of Genetics, University of Regensburg, D-93040 Regensburg, Germany
| | - Lea Neumann-Arnold
- Department of Genetics, University of Regensburg, D-93040 Regensburg, Germany
| | - Wolfgang Seufert
- Department of Genetics, University of Regensburg, D-93040 Regensburg, Germany
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9
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Saxena N, Kumar V. The HBx oncoprotein of hepatitis B virus deregulates the cell cycle by promoting the intracellular accumulation and re-compartmentalization of the cellular deubiquitinase USP37. PLoS One 2014; 9:e111256. [PMID: 25347529 PMCID: PMC4210131 DOI: 10.1371/journal.pone.0111256] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2014] [Accepted: 09/16/2014] [Indexed: 01/25/2023] Open
Abstract
The HBx oncoprotein of hepatitis B Virus has been accredited as one of the protagonists in driving hepatocarcinogenesis. HBx exerts its influence over the cell cycle progression by potentiating the activity of cyclin A/E-CDK2 complex, the Cyclin A partner of which is a well-known target of cellular deubiquitinase USP37. In the present study, we observed the intracellular accumulation of cyclin A and USP37 proteins under the HBx microenvironment. Flow cytometry analysis of the HBx-expressing cells showed deregulation of cell cycle apparently due to the enhanced gene expression and stabilization of USP37 protein and deubiquitination of Cyclin A by USP37. Our co-immunoprecipitation and confocal microscopic studies suggested a direct interaction between USP37 and HBx. This interaction promoted the translocation of USP37 outside the nucleus and prevented its association and ubiquitination by E3 ubiquitin ligases - APC/CDH1 and SCF/β-TrCP. Thus, HBx seems to control the cell cycle progression via the cyclin A-CDK2 complex by regulating the intracellular distribution and stability of deubiquitinase USP37.
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Affiliation(s)
- Nehul Saxena
- Virology Group, International Center for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi, India
| | - Vijay Kumar
- Virology Group, International Center for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi, India
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10
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Lai F, Hu K, Wu Y, Tang J, Sang Y, Cao J, Kang T. Human KIAA1018/FAN1 nuclease is a new mitotic substrate of APC/C(Cdh1). CHINESE JOURNAL OF CANCER 2012; 31:440-8. [PMID: 22854063 PMCID: PMC3777502 DOI: 10.5732/cjc.012.10144] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
A recently identified protein, FAN1 (FANCD2-associated nuclease 1, previously known as KIAA1018), is a novel nuclease associated with monoubiquitinated FANCD2 that is required for cellular resistance against DNA interstrand crosslinking (ICL) agents. The mechanisms of FAN1 regulation have not yet been explored. Here, we provide evidence that FAN1 is degraded during mitotic exit, suggesting that FAN1 may be a mitotic substrate of the anaphase-promoting cyclosome complex (APC/C). Indeed, Cdh1, but not Cdc20, was capable of regulating the protein level of FAN1 through the KEN box and the D-box. Moreover, the up- and down-regulation of FAN1 affected the progression to mitotic exit. Collectively, these data suggest that FAN1 may be a new mitotic substrate of APC/CCdh1 that plays a key role during mitotic exit.
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Affiliation(s)
- Fenju Lai
- State Key Laboratory of Oncology in South China, Department of Experimental Research, Sun Yat-sen University Cancer Center, Guangzhou, Guangdong 510060, PR China
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11
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Regulation of APC/C-Cdh1 and its function in neuronal survival. Mol Neurobiol 2012; 46:547-54. [PMID: 22836916 PMCID: PMC3496556 DOI: 10.1007/s12035-012-8309-2] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2012] [Accepted: 07/12/2012] [Indexed: 12/22/2022]
Abstract
Neurons are post-mitotic cells that undergo an active downregulation of cell cycle-related proteins to survive. The activity of the anaphase-promoting complex/cyclosome (APC/C), an E3 ubiquitin ligase that regulates cell cycle progression in proliferating cells, plays a relevant role in post-mitotic neurons. Recent advances in the study of the regulation of APC/C have documented that the APC/C-activating cofactor, Cdh1, is essential for the function(s) of APC/C in neuronal survival. Here, we review the normal regulation of APC/C activity in proliferating cells and neurons. We conclude that in neurons the APC/C-Cdh1 complex actively downregulates the stability of the cell cycle protein cyclin B1 and the glycolytic enzyme 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase-3. Keeping these proteins destabilized is critical both for preventing the aberrant reentry of post-mitotic neurons into the cell cycle and for maintaining their reduced antioxidant status. Further understanding of the pathophysiological regulation of these proteins by APC/C-Cdh1 in neurons will be important for the search for novel therapeutic targets against neurodegeneration.
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12
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Su'udi M, Cha JY, Jung MH, Ermawati N, Han CD, Kim MG, Woo YM, Son D. Potential role of the rice OsCCS52A gene in endoreduplication. PLANTA 2012; 235:387-397. [PMID: 21927949 DOI: 10.1007/s00425-011-1515-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2011] [Accepted: 08/29/2011] [Indexed: 05/31/2023]
Abstract
In eukaryotes, the cell cycle consists of four distinct phases: G1, S, G2 and M. In certain condition, the cells skip M-phase and undergo endoreduplication. Endoreduplication, occurring during a modified cell cycle, duplicates the entire genome without being followed by M-phase. A cycle of endoreduplication is common in most of the differentiated cells of plant vegetative tissues and it occurs extensively in cereal endosperm cells. Endoreduplication occurs when CDK/Cyclin complex low or inactive caused by ubiquitin-mediated degradation by APC and their activators. In this study, rice cell cycle switch 52 A (OsCCS52A), an APC activator, is functionally characterized using the reverse genetic approach. In rice, OsCCS52A is highly expressed in seedlings, flowers, immature panicles and 15 DAP kernels. Localization studies revealed that OsCCS52A is a nuclear protein. OsCCS52A interacts with OsCdc16 in yeast. In addition, overexpression of OsCCS52A inhibits mitotic cell division and induces endoreduplication and cell elongation in fission yeast. The homozygous mutant exhibits dwarfism and smaller seeds. Further analysis demonstrated that endoreduplication cycles in the endosperm of mutant seeds were disturbed, evidenced by reduced nuclear and cell sizes. Taken together, these results suggest that OsCCS52A is involved in maintaining normal seed size formation by mediating the exit from mitotic cell division to enter the endoreduplication cycles in rice endosperm.
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MESH Headings
- Amino Acid Sequence
- Anaphase-Promoting Complex-Cyclosome
- Cell Cycle Proteins/genetics
- Cell Cycle Proteins/metabolism
- Cell Enlargement
- Cell Nucleus/genetics
- Cell Nucleus/metabolism
- Cell Size
- Cloning, Molecular
- Crops, Agricultural/genetics
- Crops, Agricultural/growth & development
- Crops, Agricultural/metabolism
- Endosperm/genetics
- Endosperm/growth & development
- Endosperm/metabolism
- Gene Expression Regulation, Plant
- Genes, Plant
- Mitosis
- Molecular Sequence Data
- Mutation
- Open Reading Frames
- Oryza/genetics
- Oryza/growth & development
- Oryza/metabolism
- Plant Components, Aerial/genetics
- Plant Components, Aerial/growth & development
- Plant Components, Aerial/metabolism
- Plant Proteins/genetics
- Plant Proteins/metabolism
- Plant Roots/genetics
- Plant Roots/metabolism
- Pollination
- RNA, Plant/genetics
- Schizosaccharomyces/genetics
- Schizosaccharomyces/metabolism
- Seedlings/genetics
- Seedlings/growth & development
- Seedlings/metabolism
- Transformation, Genetic
- Two-Hybrid System Techniques
- Ubiquitin-Protein Ligase Complexes/genetics
- Ubiquitin-Protein Ligase Complexes/metabolism
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Affiliation(s)
- Mukhamad Su'udi
- Division of Applied Life Science, BK21 Program, Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju 660-701, Republic of Korea
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13
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Holt JE, Weaver J, Jones KT. Spatial regulation of APCCdh1-induced cyclin B1 degradation maintains G2 arrest in mouse oocytes. Development 2010; 137:1297-304. [PMID: 20223764 DOI: 10.1242/dev.047555] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Within the mammalian ovary, oocytes remain arrested at G2 for several years. Then a peri-ovulatory hormonal cue triggers meiotic resumption by releasing an inhibitory phosphorylation on the kinase Cdk1. G2 arrest, however, also requires control in the concentrations of the Cdk1-binding partner cyclin B1, a process achieved by anaphase-promoting complex (APC(Cdh1)) activity, which ubiquitylates and so targets cyclin B1 for degradation. Thus, APC(Cdh1) activity prevents precocious meiotic entry by promoting cyclin B1 degradation. However, it remains unresolved how cyclin B1 levels are suppressed sufficiently to maintain arrest but not so low that they make oocytes hormonally insensitive. Here, we examined spatial control of this process by determining the intracellular location of the proteins involved and using nuclear-targeted cyclin B1. We found that raising nuclear cyclin B1 concentrations, an event normally observed in the minutes before nuclear envelope breakdown, was a very effective method of inducing the G2/M transition. Oocytes expressed only the alpha-isoform of Cdh1, which was predominantly nuclear, as were Cdc27 and Psmd11, core components of the APC and the 26S proteasome, respectively. Furthermore, APC(Cdh1) activity appeared higher in the nucleus, as nuclear-targeted cyclin B1 was degraded at twice the rate of wild-type cyclin B1. We propose a simple spatial model of G2 arrest in which nuclear APC(Cdh1)-proteasomal activity guards against any cyclin B1 accumulation mediated by nuclear import.
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Affiliation(s)
- Janet E Holt
- School of Biomedical Sciences, University of Newcastle, Callaghan, NSW 2308, Australia
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14
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Ibrahim B, Schmitt E, Dittrich P, Diekmann S. In silico study of kinetochore control, amplification, and inhibition effects in MCC assembly. Biosystems 2009; 95:35-50. [DOI: 10.1016/j.biosystems.2008.06.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2007] [Revised: 06/16/2008] [Accepted: 06/24/2008] [Indexed: 02/07/2023]
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15
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Torres MP, Borchers CH. Mitotic phosphorylation of the anaphase-promoting complex inhibitory subunit Mnd2 is necessary for efficient progression through meiosis i. J Biol Chem 2007; 282:17351-62. [PMID: 17459880 DOI: 10.1074/jbc.m610841200] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The yeast anaphase-promoting complex (APC) subunit Mnd2 is necessary for maintaining sister chromatid cohesion in prophase I of meiosis by inhibiting premature ubiquitination and subsequent degradation of substrates by the APC(Ama1) ubiquitin ligase. In a proteomics screen for post-translational modifications on the APC, we discovered that Mnd2 is phosphorylated during mitosis in a cell cycle-dependent manner. We identified and characterized the sites of mitotic Mnd2 phosphorylation during the cell cycle. Collective mutation of Mnd2 phosphorylation sites to alanine had no effect on vegetative growth but a striking effect (>85% reduction) on the percentage of tetrad-forming cells compared with the wild type strain. Similar to the MND2 deletion strain, cells harboring the alanine mutant that did not form spores arrested after premeiotic S phase with a single undivided nucleus and low levels of the APC(Ama1) meiotic substrate, Clb5, relative to wild type cells. In contrast, collective mutation of Mnd2 phosphorylation sites to aspartic acid resulted in partial suppression of the sporulation defect. No differences were observed in the binding between each Mnd2 isoform and the APC in vitro. However, in vivo, we observed a gradient in the abundance of APC-associated Mnd2 in each strain that was proportional to the observed differences in sporulation and Clb5 levels. Taken together, these data suggest that mitotic phosphorylation of Mnd2 is necessary for APC-mediated progression beyond the first meiotic nuclear division.
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Affiliation(s)
- Matthew P Torres
- Department of Biochemistry and Biophysics, The University of North Carolina, Chapel Hill, North Carolina 27599, USA
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Chin KT, Xu HT, Ching YP, Jin DY. Differential subcellular localization and activity of kelch repeat proteins KLHDC1 and KLHDC2. Mol Cell Biochem 2006; 296:109-19. [PMID: 16964437 DOI: 10.1007/s11010-006-9304-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2006] [Accepted: 08/10/2006] [Indexed: 10/24/2022]
Abstract
We have previously identified and characterized human KLHDC2/HCLP-1, a kelch repeat protein that interacts with and inhibits transcription factor LZIP. In this study, we identified and characterized a paralog of KLHDC2 called KLHDC1. KLHDC1 and KLHDC2 share about 50% identity at the level of amino acid sequence and both gene loci localize to human chromosome 14q21.3. This cluster of KLHDC1 and KLHDC2 genes is highly conserved in vertebrates ranging from pufferfish to human. Both genes are expressed highly in skeletal muscle, but weakly in various other tissues. While KLHDC2 was predominantly found in the nucleus, KLHDC1 is a cytoplasmic protein. Neither KLHDC1 nor KLHDC2 binds to actin. In addition, KLHDC1 was unable to inhibit LZIP/CREB3-mediated transcriptional activation. Thus, KLHDC1 and KLHDC2 have differential localization and activity in cultured mammalian cells.
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Affiliation(s)
- King-Tung Chin
- Department of Biochemistry, The University of Hong Kong, 3/F, Laboratory Block, Faculty of Medicine Building, 21 Sassoon Road, Hong Kong, China
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Vinogradova TM, Balashova EE, Smirnov VN, Bystrevskaya VB. Detection of the centriole tyr- or acet-tubulin changes in endothelial cells treated with thrombin using microscopic immunocytochemistry. ACTA ACUST UNITED AC 2005; 62:1-12. [PMID: 16001397 DOI: 10.1002/cm.20079] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
We used electron microscopic immunocytochemistry to examine the pattern of centriolar staining for tyrosinated or acetylated alpha-tubulin in endothelial cells during short-term incubation with thrombin. Endothelial cells isolated from human aorta (HAEC) and those isolated from umbilical vein (HUVEC) displayed an increase in the intensity of centriolar staining for acet-tubulin within 1 min after thrombin addition. A decrease in the intensity of centriolar staining for tyr-tubulin was detected in HUVEC within 1 min after thrombin addition, while in HAEC centriolar staining for tyr-tubulin became less intense only 5 min later. Mother and daughter centrioles of HUVEC cells displayed different intensity of immunostaining for acet-tubulin and showed no significant variation in the number of subdistal appendages after thrombin addition. Differently, HAEC cells had the same staining pattern of mother and daughter centrioles in both thrombin-untreated and thrombin-treated cultures. A sharp increase in the number of subdistal appendages of mother centriole occurred in HAEC within 5 min of incubation with thrombin. Our findings provided the direct evidence for centrosome involvement in the ligand-mediated signaling events and showed for the first time that ligand-dependent centrosome reorganization includes the centriole per se. Furthermore, based on our observations we would like to propose that MT-nucleating/anchoring properties of the centrosome are subject to rapid regulation by external signals such as thrombin.
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Sze KMF, Ching YP, Jin DY, Ng IOL. Association of MAD2 expression with mitotic checkpoint competence in hepatoma cells. J Biomed Sci 2004; 11:920-7. [PMID: 15591789 DOI: 10.1007/bf02254377] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2004] [Accepted: 05/15/2004] [Indexed: 10/25/2022] Open
Abstract
Chromosomal instability (CIN) refers to high rates of chromosomal gains and losses and is a major cause of genomic instability of cells. It is thought that CIN caused by loss of mitotic checkpoint contributes to carcinogenesis. In this study, we evaluated the competence of mitotic checkpoint in hepatoma cells and investigated the cause of mitotic checkpoint defects. We found that 6 (54.5%) of the 11 hepatoma cell lines were defective in mitotic checkpoint control as monitored by mitotic indices and flow-cytometric analysis after treatment with microtubule toxins. Interestingly, all 6 hepatoma cell lines with defective mitotic checkpoint showed significant underexpression of mitotic arrest deficient 2 (MAD2), a key mitotic checkpoint protein. The level of MAD2 underexpression was significantly associated with defective mitotic checkpoint response (p < 0.001). In addition, no mutations were found in the coding sequences of MAD2 in all 11 hepatoma cell lines. Our findings suggest that MAD2 deficiency may cause a mitotic checkpoint defect in hepatoma cells.
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Affiliation(s)
- Karen Man-Fong Sze
- Department of Pathology, University of Hong Kong, Faculty of Medicine, Hong Kong, China
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Tarayre S, Vinardell JM, Cebolla A, Kondorosi A, Kondorosi E. Two classes of the CDh1-type activators of the anaphase-promoting complex in plants: novel functional domains and distinct regulation. THE PLANT CELL 2004; 16:422-34. [PMID: 14742878 PMCID: PMC341914 DOI: 10.1105/tpc.018952] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2003] [Accepted: 12/12/2003] [Indexed: 05/17/2023]
Abstract
The Cdc20 and Cdh1/Fzr proteins are the substrate-specific activators of the anaphase-promoting complex (APC). In Medicago truncatula, the MtCcs52A and MtCcs52B proteins represent two subgroups of the Cdh1-type activators, which display differences in their cell cycle regulation, structure, and function. The ccs52A transcripts are present in all phases of the cell cycle. By contrast, expression of ccs52B is restricted to late G2-phase and M-phase, and its induced overexpression in BY2 cells inhibited mitosis. MtCcs52A is active in Schizosaccharomyces pombe and binds to the S. pombe APC, whereas MtCcs52B does not because of differences in the N-terminal region. We identified a new functional domain, the Cdh1-specific motif conserved in the Cdh1 proteins that, in addition to the C-box and the terminal Ile and Arg residues, was essential for the activity and required for efficient binding to the APC. Moreover, we demonstrate that cyclin-dependent kinase phosphorylation sites adjacent to the C-box may regulate the interaction with the APC. In the different plant organs, the expression of Mtccs52A and Mtccs52B displayed differences and indicated the involvement of the APC in differentiation processes.
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Affiliation(s)
- Sylvie Tarayre
- Institut des Sciences du Végétal, 91198 Gif-sur-Yvette, France
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