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Li J, Dai F, Kou X, Wu B, Xu J, He S. β-Actin: An Emerging Biomarker in Ischemic Stroke. Cell Mol Neurobiol 2023; 43:683-696. [PMID: 35556192 DOI: 10.1007/s10571-022-01225-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 04/10/2022] [Indexed: 11/03/2022]
Abstract
At present, the diagnosis of ischemic stroke mainly depends on neuroimaging technology, but it still has many limitations. Therefore, it is very important to find new biomarkers of ischemic stroke. Recently, β-actin has attracted extensive attention as a biomarker of a variety of cancers. Although several recent studies have been investigating its role in ischemic stroke and other cerebrovascular diseases, the understanding of this emerging biomarker in neurology is still limited. We examined human and preclinical studies to gain a comprehensive understanding of the literature on the subject. Most relevant literatures focus on preclinical research, and pay more attention to the role of β-actin in the process of cerebral ischemia, but some recent literatures reported that in human studies, serum β-actin increased significantly in the early stage of acute cerebral ischemia. This review will investigate the basic biology of β-actin, pay attention to the potential role of serum β-actin as an early diagnostic blood biomarker of ischemic stroke, and explore its potential mechanism in ischemic stroke and new strategies for stroke treatment in the future.
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Affiliation(s)
- Jiaqian Li
- Department of Neurology, School of Medicine, Zhoushan Hospital, Zhejiang University, Zhoushan, 316000, Zhejiang Province, China
| | - Fangyu Dai
- Department of Neurology, School of Medicine, Zhoushan Hospital, Zhejiang University, Zhoushan, 316000, Zhejiang Province, China
| | - Xuelian Kou
- Department of Neurology, School of Medicine, Zhoushan Hospital, Zhejiang University, Zhoushan, 316000, Zhejiang Province, China
| | - Bin Wu
- Department of Neurology, School of Medicine, Zhoushan Hospital, Zhejiang University, Zhoushan, 316000, Zhejiang Province, China
| | - Jie Xu
- Department of Neurology, School of Medicine, Zhoushan Hospital, Zhejiang University, Zhoushan, 316000, Zhejiang Province, China
| | - Songbin He
- Department of Neurology, School of Medicine, Zhoushan Hospital, Zhejiang University, Zhoushan, 316000, Zhejiang Province, China.
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The p53 and Calcium Regulated Actin Rearrangement in Model Cells. Int J Mol Sci 2022; 23:ijms23169078. [PMID: 36012344 PMCID: PMC9408879 DOI: 10.3390/ijms23169078] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Revised: 08/04/2022] [Accepted: 08/11/2022] [Indexed: 11/17/2022] Open
Abstract
Long-term cellular stress maintains high intracellular Ca2+ concentrations which ultimately initiates apoptosis. Our interest is focused on how the gelsolin (GSN) and junctional mediating and regulating Y protein (JMY) play important roles in stress response. Both of these proteins can bind p53 and actin. We investigated using in vitro fluorescence spectroscopy and found that the p53 competes with actin in GSN to inhibit p53–JMY complex formation. A high Ca2+ level initializes p53 dimerization; the dimer competes with actin on JMY, which can lead to p53–JMY cotransport into the nucleus. Here we investigated how the motility and division rate of HeLa cells changes due to low-voltage electroporation of GSN or JMY in scratching assays. We revealed that JMY inhibits their motion, but that it can accelerate the cell division. GSN treatment slows down cell division but does not affect cell motility. HeLa cells fully recovered the gap 20 h after the electroporation with JMY and then started to release from the glass slides. Taken together, our in vitro results indicate that GSN and JMY may play an important role in the cellular stress response.
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Abstract
The presence of actin in the nucleus has historically been a highly contentious issue. It is now, however, well accepted that actin has physiologically important roles in the nucleus. In this Review, we describe the evolution of our thinking about actin in the nucleus starting with evidence supporting its involvement in transcription, chromatin remodeling and intranuclear movements. We also review the growing literature on the mechanisms that regulate the import and export of actin and how post-translational modifications of actin could regulate nuclear actin. We end with an extended discussion of the role of nuclear actin in the repair of DNA double stranded breaks.
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Affiliation(s)
- Leonid Serebryannyy
- Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago, IL 60612, United States
| | - Primal de Lanerolle
- Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago, IL 60612, United States.
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Venit T, Mahmood SR, Endara-Coll M, Percipalle P. Nuclear actin and myosin in chromatin regulation and maintenance of genome integrity. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2020; 355:67-108. [DOI: 10.1016/bs.ircmb.2020.05.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/06/2022]
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6
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Klages-Mundt NL, Kumar A, Zhang Y, Kapoor P, Shen X. The Nature of Actin-Family Proteins in Chromatin-Modifying Complexes. Front Genet 2018; 9:398. [PMID: 30319687 PMCID: PMC6167448 DOI: 10.3389/fgene.2018.00398] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 08/31/2018] [Indexed: 01/25/2023] Open
Abstract
Actin is not only one of the most abundant proteins in eukaryotic cells, but also one of the most versatile. In addition to its familiar involvement in enabling contraction and establishing cellular motility and scaffolding in the cytosol, actin has well-documented roles in a variety of processes within the confines of the nucleus, such as transcriptional regulation and DNA repair. Interestingly, monomeric actin as well as actin-related proteins (Arps) are found as stoichiometric subunits of a variety of chromatin remodeling complexes and histone acetyltransferases, raising the question of precisely what roles they serve in these contexts. Actin and Arps are present in unique combinations in chromatin modifiers, helping to establish structural integrity of the complex and enabling a wide range of functions, such as recruiting the complex to nucleosomes to facilitate chromatin remodeling and promoting ATPase activity of the catalytic subunit. Actin and Arps are also thought to help modulate chromatin dynamics and maintain higher-order chromatin structure. Moreover, the presence of actin and Arps in several chromatin modifiers is necessary for promoting genomic integrity and an effective DNA damage response. In this review, we discuss the involvement of actin and Arps in these nuclear complexes that control chromatin remodeling and histone modifications, while also considering avenues for future study to further shed light on their functional importance.
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Affiliation(s)
- Naeh L Klages-Mundt
- Science Park Research Division, Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Houston, TX, United States.,Program in Genetics & Epigenetics, The University of Texas MD Anderson Cancer Center, UTHealth Graduate School of Biomedical Sciences, Houston, TX, United States
| | - Ashok Kumar
- Department of Cellular and Molecular Biology, The University of Texas Health Science Center at Tyler, Tyler, TX, United States
| | - Yuexuan Zhang
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Prabodh Kapoor
- Department of Cellular and Molecular Biology, The University of Texas Health Science Center at Tyler, Tyler, TX, United States
| | - Xuetong Shen
- Science Park Research Division, Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Houston, TX, United States.,Program in Genetics & Epigenetics, The University of Texas MD Anderson Cancer Center, UTHealth Graduate School of Biomedical Sciences, Houston, TX, United States
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7
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Ermakov A, Daks A, Fedorova O, Shuvalov O, Barlev NA. Ca 2+ -depended signaling pathways regulate self-renewal and pluripotency of stem cells. Cell Biol Int 2018; 42:1086-1096. [PMID: 29851182 DOI: 10.1002/cbin.10998] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2017] [Accepted: 05/25/2018] [Indexed: 12/15/2022]
Abstract
Ca2+ -mediated signaling is widely spread in nature and plays critical role in the individual development of various organisms ranging from microorganisms to mammals. In vertebrates, Ca2+ is involved in important developmental events: fertilization, body plan establishment, and organogenesis. The two later events are defined by embryonic stem cells (ESCs). ESCs are capable of self-renewal and are pluripotent by nature, that is, can give rise to all types of cells that make up the body. Given the paramount importance of Ca2+ signalization in the development, it is therefore not surprising this process also plays role in the biology of stem cells. In this review, we scrutinize the published experimental data on the role of Ca2+ ions in embryonic stem cells self-renewal and pluripotency. In line with this, we also discuss possible mechanisms of p53 inhibition as a major hindrance to self-renewal of ESCs. Finally, we argue about the role of G-protein-coupled receptors (GPCRs), the largest family of heteromeric transmembrane receptors, and GPCR-mediated signalization in stem cells, and propose the role for the GPCR-G-protein-PLC-Ca2+ -downstream signaling pathway in the regulation of pluripotency of both mouse and human ESCs.
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Affiliation(s)
| | - Alexandra Daks
- Institute of Cytology RAS, Saint-Petersburg 194064, Russia
| | - Olga Fedorova
- Institute of Cytology RAS, Saint-Petersburg 194064, Russia
| | - Oleg Shuvalov
- Institute of Cytology RAS, Saint-Petersburg 194064, Russia
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8
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Barabutis N, Dimitropoulou C, Gregory B, Catravas JD. Wild-type p53 enhances endothelial barrier function by mediating RAC1 signalling and RhoA inhibition. J Cell Mol Med 2018; 22:1792-1804. [PMID: 29363851 PMCID: PMC5824363 DOI: 10.1111/jcmm.13460] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Accepted: 10/02/2017] [Indexed: 12/13/2022] Open
Abstract
Inflammation is the major cause of endothelial barrier hyper‐permeability, associated with acute lung injury and acute respiratory distress syndrome. This study reports that p53 “orchestrates” the defence of vascular endothelium against LPS, by mediating the opposing actions of Rac1 and RhoA in pulmonary tissues. Human lung microvascular endothelial cells treated with HSP90 inhibitors activated both Rac1‐ and P21‐activated kinase, which is an essential element of vascular barrier function. 17AAG increased the phosphorylation of both LIMK and cofilin, in contrast to LPS which counteracted those effects. Mouse lung microvascular endothelial cells exposed to LPS exhibited decreased expression of phospho‐cofilin. 17AAG treatment resulted in reduced levels of active cofilin. Silencing of cofilin pyridoxal phosphate phosphatase (PDXP) blocked the LPS‐induced hyper‐permeability, and P53 inhibition reversed the 17AAG‐induced PDXP down‐regulation. P190RHOGAP suppression enhanced the LPS‐triggered barrier dysfunction in endothelial monolayers. 17AAG treatment resulted in P190RHOGAP induction and blocked the LPS‐induced pMLC2 up‐regulation in wild‐type mice. Pulmonary endothelial cells from “super p53” mice, which carry additional p53‐tg alleles, exhibited a lower response to LPS than the controls. Collectively, our findings help elucidate the mechanisms by which p53 operates to enhance barrier function.
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Affiliation(s)
- Nektarios Barabutis
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, USA
| | | | - Betsy Gregory
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, USA
| | - John D Catravas
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, USA.,School of Medical Diagnostic & Translational Sciences, College of Health Sciences, Old Dominion University, Norfolk, VA, USA
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9
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Serebryannyy LA, Yemelyanov A, Gottardi CJ, de Lanerolle P. Nuclear α-catenin mediates the DNA damage response via β-catenin and nuclear actin. J Cell Sci 2017; 130:1717-1729. [PMID: 28348105 DOI: 10.1242/jcs.199893] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Accepted: 03/20/2017] [Indexed: 12/29/2022] Open
Abstract
α-Catenin is an F-actin-binding protein widely recognized for its role in cell-cell adhesion. However, a growing body of literature indicates that α-catenin is also a nuclear protein. In this study, we show that α-catenin is able to modulate the sensitivity of cells to DNA damage and toxicity. Furthermore, nuclear α-catenin is actively recruited to sites of DNA damage. This recruitment occurs in a β-catenin-dependent manner and requires nuclear actin polymerization. These findings provide mechanistic insight into the WNT-mediated regulation of the DNA damage response and suggest a novel role for the α-catenin-β-catenin complex in the nucleus.
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Affiliation(s)
- Leonid A Serebryannyy
- Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Alex Yemelyanov
- Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Cara J Gottardi
- Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Primal de Lanerolle
- Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago, IL 60612, USA
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10
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G-actin guides p53 nuclear transport: potential contribution of monomeric actin in altered localization of mutant p53. Sci Rep 2016; 6:32626. [PMID: 27601274 PMCID: PMC5013524 DOI: 10.1038/srep32626] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Accepted: 08/11/2016] [Indexed: 12/23/2022] Open
Abstract
p53 preserves genomic integrity by restricting anomaly at the gene level. Till date, limited information is available for cytosol to nuclear shuttling of p53; except microtubule-based trafficking route, which utilizes minus-end directed motor dynein. The present study suggests that monomeric actin (G-actin) guides p53 traffic towards the nucleus. Histidine-tag pull-down assay using purified p53(1–393)-His and G-actin confirms direct physical association between p53 and monomeric G-actin. Co-immunoprecipitation data supports the same. Confocal imaging explores intense perinuclear colocalization between p53 and G-actin. To address atomistic details of the complex, constraint-based docked model of p53:G-actin complex was generated based on crystal structures. MD simulation reveals that p53 DNA-binding domain arrests very well the G-actin protein. Docking benchmark studies have been carried out for a known crystal structure, 1YCS (complex between p53DBD and BP2), which validates the docking protocol we adopted. Co-immunoprecipitation study using “hot-spot” p53 mutants suggested reduced G-actin association with cancer-associated p53 conformational mutants (R175H and R249S). Considering these findings, we hypothesized that point mutation in p53 structure, which diminishes p53:G-actin complexation results in mutant p53 altered subcellular localization. Our model suggests p53Arg249 form polar-contact with Arg357 of G-actin, which upon mutation, destabilizes p53:G-actin interaction and results in cytoplasmic retention of p53R249S.
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11
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Chang CY, Leu JD, Lee YJ. The actin depolymerizing factor (ADF)/cofilin signaling pathway and DNA damage responses in cancer. Int J Mol Sci 2015; 16:4095-120. [PMID: 25689427 PMCID: PMC4346946 DOI: 10.3390/ijms16024095] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Revised: 01/26/2015] [Accepted: 02/09/2015] [Indexed: 01/06/2023] Open
Abstract
The actin depolymerizing factor (ADF)/cofilin protein family is essential for actin dynamics, cell division, chemotaxis and tumor metastasis. Cofilin-1 (CFL-1) is a primary non-muscle isoform of the ADF/cofilin protein family accelerating the actin filamental turnover in vitro and in vivo. In response to environmental stimulation, CFL-1 enters the nucleus to regulate the actin dynamics. Although the purpose of this cytoplasm-nucleus transition remains unclear, it is speculated that the interaction between CFL-1 and DNA may influence various biological responses, including DNA damage repair. In this review, we will discuss the possible involvement of CFL-1 in DNA damage responses (DDR) induced by ionizing radiation (IR), and the implications for cancer radiotherapy.
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Affiliation(s)
- Chun-Yuan Chang
- Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei 112, Taiwan.
| | - Jyh-Der Leu
- Division of Radiation Oncology, Taipei City Hospital RenAi Branch, Taipei 106, Taiwan.
| | - Yi-Jang Lee
- Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei 112, Taiwan.
- Biophotonics & Molecular Imaging Research Center (BMIRC), National Yang-Ming University, Taipei 112, Taiwan.
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Ditlev JA, Mayer BJ, Loew LM. There is more than one way to model an elephant. Experiment-driven modeling of the actin cytoskeleton. Biophys J 2013; 104:520-32. [PMID: 23442903 DOI: 10.1016/j.bpj.2012.12.044] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2012] [Revised: 12/20/2012] [Accepted: 12/21/2012] [Indexed: 10/27/2022] Open
Abstract
Mathematical modeling has established its value for investigating the interplay of biochemical and mechanical mechanisms underlying actin-based motility. Because of the complex nature of actin dynamics and its regulation, many of these models are phenomenological or conceptual, providing a general understanding of the physics at play. But the wealth of carefully measured kinetic data on the interactions of many of the players in actin biochemistry cries out for the creation of more detailed and accurate models that could permit investigators to dissect interdependent roles of individual molecular components. Moreover, no human mind can assimilate all of the mechanisms underlying complex protein networks; so an additional benefit of a detailed kinetic model is that the numerous binding proteins, signaling mechanisms, and biochemical reactions can be computationally organized in a fully explicit, accessible, visualizable, and reusable structure. In this review, we will focus on how comprehensive and adaptable modeling allows investigators to explain experimental observations and develop testable hypotheses on the intracellular dynamics of the actin cytoskeleton.
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Affiliation(s)
- Jonathon A Ditlev
- Richard D. Berlin Center for Cell Analysis and Modeling, University of Connecticut Health Center, Farmington, Connecticut, USA
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13
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Wang L, Wang M, Wang S, Qi T, Guo L, Li J, Qi W, Ampah KK, Ba X, Zeng X. Actin polymerization negatively regulates p53 function by impairing its nuclear import in response to DNA damage. PLoS One 2013; 8:e60179. [PMID: 23565200 PMCID: PMC3615075 DOI: 10.1371/journal.pone.0060179] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2012] [Accepted: 02/25/2013] [Indexed: 11/29/2022] Open
Abstract
Actin, one of the most evolutionarily conservative proteins in eukaryotes, is distributed both in the cytoplasm and the nucleus, and its dynamics plays important roles in numerous cellular processes. Previous evidence has shown that actin interacts with p53 and this interaction increases in the process of p53 responding to DNA damage, but the physiological significance of their interaction remains elusive. Here, we show that DNA damage induces both actin polymerization and p53 accumulation. To further understand the implication of actin polymerization in p53 function, cells were treated with actin aggregation agent. We find that the protein level of p53 decrease. The change in p53 is a consequence of the polymeric actin anchoring p53 in the cytoplasm, thus impairing p53 nuclear import. Analysis of phosphorylation and ubiquitination of p53 reveals that actin polymerization promotes the p53 phosphorylation at Ser315 and reduces the stabilization of p53 by recruiting Aurora kinase A. Taken together, our results suggest that the actin polymerization serves as a negative modulator leading to the impairment of nuclear import and destabilization of p53. On the basis of our results, we propose that actin polymerization might be a factor participating in the process of orchestrating p53 function in response to DNA damage.
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Affiliation(s)
- Ling Wang
- Key Laboratory of Molecular Epigenetics of MOE and the Institute of Genetics and Cytology, Northeast Normal University, Changchun, Jilin, China
| | - Min Wang
- Key Laboratory of Molecular Epigenetics of MOE and the Institute of Genetics and Cytology, Northeast Normal University, Changchun, Jilin, China
| | - Shuyan Wang
- Key Laboratory of Molecular Epigenetics of MOE and the Institute of Genetics and Cytology, Northeast Normal University, Changchun, Jilin, China
| | - Tianyang Qi
- Key Laboratory of Molecular Epigenetics of MOE and the Institute of Genetics and Cytology, Northeast Normal University, Changchun, Jilin, China
| | - Lijing Guo
- Key Laboratory of Molecular Epigenetics of MOE and the Institute of Genetics and Cytology, Northeast Normal University, Changchun, Jilin, China
| | - Jinjiao Li
- Key Laboratory of Molecular Epigenetics of MOE and the Institute of Genetics and Cytology, Northeast Normal University, Changchun, Jilin, China
| | - Wenjing Qi
- Key Laboratory of Molecular Epigenetics of MOE and the Institute of Genetics and Cytology, Northeast Normal University, Changchun, Jilin, China
| | - Khamal Kwesi Ampah
- Key Laboratory of Molecular Epigenetics of MOE and the Institute of Genetics and Cytology, Northeast Normal University, Changchun, Jilin, China
| | - Xueqing Ba
- Key Laboratory of Molecular Epigenetics of MOE and the Institute of Genetics and Cytology, Northeast Normal University, Changchun, Jilin, China
- * E-mail: (XB); (XZ)
| | - Xianlu Zeng
- Key Laboratory of Molecular Epigenetics of MOE and the Institute of Genetics and Cytology, Northeast Normal University, Changchun, Jilin, China
- * E-mail: (XB); (XZ)
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14
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Simon DN, Wilson KL. The nucleoskeleton as a genome-associated dynamic 'network of networks'. Nat Rev Mol Cell Biol 2011; 12:695-708. [PMID: 21971041 DOI: 10.1038/nrm3207] [Citation(s) in RCA: 219] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
In the cytosol, actin polymers, intermediate filaments and microtubules can anchor to cell surface adhesions and interlink to form intricate networks. This cytoskeleton is anchored to the nucleus through LINC (links the nucleoskeleton and cytoskeleton) complexes that span the nuclear envelope and in turn anchor to networks of filaments in the nucleus. The metazoan nucleoskeleton includes nuclear pore-linked filaments, A-type and B-type lamin intermediate filaments, nuclear mitotic apparatus (NuMA) networks, spectrins, titin, 'unconventional' polymers of actin and at least ten different myosin and kinesin motors. These elements constitute a poorly understood 'network of networks' that dynamically reorganizes during mitosis and is responsible for genome organization and integrity.
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Affiliation(s)
- Dan N Simon
- Department of Cell Biology, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
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15
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LATS1 tumor suppressor is a novel actin-binding protein and negative regulator of actin polymerization. Cell Res 2011; 21:1513-6. [PMID: 21808298 DOI: 10.1038/cr.2011.122] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
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16
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Compton S, Kim C, Griner NB, Potluri P, Scheffler IE, Sen S, Jerry DJ, Schneider S, Yadava N. Mitochondrial dysfunction impairs tumor suppressor p53 expression/function. J Biol Chem 2011; 286:20297-312. [PMID: 21502317 DOI: 10.1074/jbc.m110.163063] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Recently, mitochondria have been suggested to act in tumor suppression. However, the underlying mechanisms by which mitochondria suppress tumorigenesis are far from being clear. In this study, we have investigated the link between mitochondrial dysfunction and the tumor suppressor protein p53 using a set of respiration-deficient (Res(-)) mammalian cell mutants with impaired assembly of the oxidative phosphorylation machinery. Our data suggest that normal mitochondrial function is required for γ-irradiation (γIR)-induced cell death, which is mainly a p53-dependent process. The Res(-) cells are protected against γIR-induced cell death due to impaired p53 expression/function. We find that the loss of complex I biogenesis in the absence of the MWFE subunit reduces the steady-state level of the p53 protein, although there is no effect on the p53 protein level in the absence of the ESSS subunit that is also essential for complex I assembly. The p53 protein level was also reduced to undetectable levels in Res(-) cells with severely impaired mitochondrial protein synthesis. This suggests that p53 protein expression is differentially regulated depending upon the type of electron transport chain/respiratory chain deficiency. Moreover, irrespective of the differences in the p53 protein expression profile, γIR-induced p53 activity is compromised in all Res(-) cells. Using two different conditional systems for complex I assembly, we also show that the effect of mitochondrial dysfunction on p53 expression/function is a reversible phenomenon. We believe that these findings will have major implications in the understanding of cancer development and therapy.
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Affiliation(s)
- Shannon Compton
- Pioneer Valley Life Sciences Institute, Springfield, Massachusetts 01107, USA
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17
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Abstract
Tunneling nanotubes (TNTs) can be induced in rat hippocampal astrocytes and neurons with H(2)O(2) or serum depletion. Major cytoskeletal component of TNTs is F-actin. TNTs transfer endoplasmic reticulum, mitochondria, Golgi, endosome and intracellular as well as extracellular amyloid β. TNT development is a property of cells under stress. When two populations of cells are co-cultured, it is the stressed cells that always develop TNTs toward the unstressed cells. p53 is crucial for TNT development. When p53 function is deleted by either dominant negative construct or siRNAs, TNT development is inhibited. In addition, we find that among the genes activated by p53, epidermal growth factor receptor is also important to TNT development. Akt, phosphoinositide 3-kinase and mTOR are involved in TNT induction. Our data suggest that TNTs might be a mechanism for cells to respond to harmful signals and transfer cellular substances or energy to another cell under stress.
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Gottlieb A, Varshavsky R, Linial M, Horn D. UFFizi: a generic platform for ranking informative features. BMC Bioinformatics 2010; 11:300. [PMID: 20525252 PMCID: PMC2893168 DOI: 10.1186/1471-2105-11-300] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2009] [Accepted: 06/03/2010] [Indexed: 11/10/2022] Open
Abstract
Background Feature selection is an important pre-processing task in the analysis of complex data. Selecting an appropriate subset of features can improve classification or clustering and lead to better understanding of the data. An important example is that of finding an informative group of genes out of thousands that appear in gene-expression analysis. Numerous supervised methods have been suggested but only a few unsupervised ones exist. Unsupervised Feature Filtering (UFF) is such a method, based on an entropy measure of Singular Value Decomposition (SVD), ranking features and selecting a group of preferred ones. Results We analyze the statistical properties of UFF and present an efficient approximation for the calculation of its entropy measure. This allows us to develop a web-tool that implements the UFF algorithm. We propose novel criteria to indicate whether a considered dataset is amenable to feature selection by UFF. Relying on formalism similar to UFF we propose also an Unsupervised Detection of Outliers (UDO) method, providing a novel definition of outliers and producing a measure to rank the "outlier-degree" of an instance. Our methods are demonstrated on gene and microRNA expression datasets, covering viral infection disease and cancer. We apply UFFizi to select genes from these datasets and discuss their biological and medical relevance. Conclusions Statistical properties extracted from the UFF algorithm can distinguish selected features from others. UFFizi is a framework that is based on the UFF algorithm and it is applicable for a wide range of diseases. The framework is also implemented as a web-tool. The web-tool is available at: http://adios.tau.ac.il/UFFizi
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Scholtysek C, Krukiewicz AA, Alonso JL, Sharma KP, Sharma PC, Goldmann WH. Characterizing components of the Saw Palmetto Berry Extract (SPBE) on prostate cancer cell growth and traction. Biochem Biophys Res Commun 2009; 379:795-8. [DOI: 10.1016/j.bbrc.2008.11.114] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2008] [Accepted: 11/20/2008] [Indexed: 10/21/2022]
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Cardoso FM, Kato SEM, Huang W, Flint SJ, Gonzalez RA. An early function of the adenoviral E1B 55 kDa protein is required for the nuclear relocalization of the cellular p53 protein in adenovirus-infected normal human cells. Virology 2008; 378:339-46. [PMID: 18632130 DOI: 10.1016/j.virol.2008.06.016] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2008] [Revised: 06/03/2008] [Accepted: 06/06/2008] [Indexed: 10/21/2022]
Abstract
It is well established that the human subgroup C adenovirus type 5 (Ad5) E1B 55 kDa protein can regulate the activity and concentration of the cellular tumor suppressor, p53. However, the contribution(s) of these functions of the E1B protein to viral reproduction remains unclear. To investigate this issue, we examined properties of p53 in normal human cells infected by E1B mutant viruses that display defective entry into the late phase or viral late mRNA export. The steady-state concentrations of p53 were significantly higher in cells infected by the E1B 55 kDa null mutant Hr6 or three mutants carrying small insertions in the E1B 55 kDa protein coding sequence than in Ad5-infected cells. Nevertheless, none of the mutants induced apoptosis in infected cells. Rather, the localization of p53 to E1B containing nuclear sites observed during infection by Ad5 was prevented by mutations that impair interaction of the E1B protein with p53 and/or with the E4 Orf6 protein. These results indicate that the E1B protein fulfills an early function that correlates efficient entry into the late phase with the localization of E1B and p53 in the nucleus of Ad5-infected normal human cells.
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Affiliation(s)
- F M Cardoso
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias, Universidad Autónoma del Estado de Morelos, Cuernavaca 62209, México
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Abstract
Much remains to be learned about how cancer cells acquire the property of migration, a prerequisite for invasiveness and metastasis. Loss of p53 functions is assumed to be a crucial step in the development of many types of cancers, leading to dysregulation of cell cycle checkpoint controls and apoptosis. However, emerging evidence shows that the contribution of the tumour suppressor p53 to the control of tumorigenesis is not restricted to its well-known anti-proliferative activities, but is extended to other stages of cancer development, i.e. the modulation of cell migration. This interesting alternative function has been proposed in light of the effect of p53 on specific features of migrating cells, including cell spreading, establishment of cell polarization and the production of protrusions. The effects of p53 on cell motility are largely mediated through the regulation of Rho signalling, thereby controlling actin cytoskeletal organization. These recent studies connect the regulation of proliferation to the control of cell migration and define a new concept of p53 function as a tumour suppressor gene, suggesting that p53 might be involved in tumour invasion and metastasis. This review focuses on emerging data concerning the properties of p53 that contribute to its atypical role in the regulation of cell migration.
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Affiliation(s)
- Lauréline Roger
- Centre de Recherche en Biochimie Macromoléculaire, CNRS FRE 2593, IFR 24, 1919 route de Mende, F-34293 Montpellier cedex 5, France
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22
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Sengupta S, Wasylyk B. Physiological and pathological consequences of the interactions of the p53 tumor suppressor with the glucocorticoid, androgen, and estrogen receptors. Ann N Y Acad Sci 2004; 1024:54-71. [PMID: 15265773 DOI: 10.1196/annals.1321.005] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The p53 tumor suppressor plays a key role in protection from the effects of different physiological stresses (DNA damage, hypoxia, transcriptional defects, etc.), and loss of its activity has dire consequences, such as cancer. Its activity is finely tuned through interactions with other important regulatory circuits in the cell. Recently, striking evidence has emerged for crosstalk with another class of important regulators, the steroid hormone receptors, and in particular the glucocorticoid (GR), androgen (AR), and estrogen (ER) receptors. These receptors are important in maintaining homeostasis in response to internal and external stresses (GR) and in the development, growth, and maintenance of the male and female reproductive systems (AR and ER, respectively). We review how p53 interacts closely with these receptors, to the extent that they share the same E3 ubiquitin ligase, the MDM2 oncoprotein. We discuss the different physiological contexts in which such interactions occur, and also how these interactions have been undermined in various pathological situations. We will describe future areas for research, with special emphasis on GR, and how certain common features, such as cytoplasmic anchoring of p53 by the receptors, may become targets for the development of therapeutic interventions. Given the importance of GR in inflammation, erythropoiesis, and autoimmune diseases, and the importance of AR and ER in prostate and breast cancer (respectively), the studies on p53 interactions with the steroid receptors will be an important domain in the near future.
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Affiliation(s)
- Sagar Sengupta
- Laboratory of Human Carcinogenesis, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
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23
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Fuszek P, Lakatos P, Tabak A, Papp J, Nagy Z, Takacs I, Horvath HC, Lakatos PL, Speer G. Relationship between serum calcium and CA 19-9 levels in colorectal cancer. World J Gastroenterol 2004; 10:1890-2. [PMID: 15222030 PMCID: PMC4572224 DOI: 10.3748/wjg.v10.i13.1890] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
AIM: To examine the calcium metabolism of colorectal cancer (CRC) in patients with colorectal cancer and control patients.
METHODS: Seventy newly diagnosed CRC patients were included. The healthy control group was age and gender matched (n = 32). Particular attention was devoted to the relationship between serum calcium of patients, and levels of AFP, CEA, carbohydrate antigen 19-9 (CA 19-9) (that could be considered as prognostic factors). Furthermore, the Ca-sensing receptor (CaSR) gene A986S polymorphism was investigated in these patients, as well as the relationship between different CaSR genotypes and the data stated above.
RESULTS: A lower level of ionized calcium (also corrected for albumin) was found in the serum of CRC patients with normal 25 (OH) vitamin D levels. The ionized calcium concentration was inversely correlated with the serum level of CA 19-9. There was no difference in the distribution of CaSR genotypes, between CRC patients and general population. The genotypes did not correlate with other data examined.
CONCLUSION: Based on these results, lower levels of serum calcium might be a pathogenic and prognostic factor in colorectal cancer.
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Affiliation(s)
- Peter Fuszek
- 1st Department of Medicine, Faculty of Medicine, Semmelweis University, 1083 Budapest, Koronyi S. u. 2/a, Hungary.
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24
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O'Brate A, Giannakakou P. The importance of p53 location: nuclear or cytoplasmic zip code? Drug Resist Updat 2004; 6:313-22. [PMID: 14744495 DOI: 10.1016/j.drup.2003.10.004] [Citation(s) in RCA: 134] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The regulation of p53 functions is tightly controlled through several mechanisms including p53 transcription and translation, protein stability, post-translational modifications, and subcellular localization. Despite intensive study of p53, the regulation of p53 subcellular localization although important for its function is still poorly understood. The regulation of p53 localization depends on factors that influence its nuclear import and export, subnuclear localization and cytoplasmic tethering and sequestration. In this review, we will focus on various proteins and modifications that regulate the location and therefore the activity of p53. For example, MDM2 is the most important regulator of p53 nuclear export and degradation. Cytoplasmic p53 associates with the microtubule cytoskeleton and the dynein family of motor proteins; while Parc and mot2 are involved in its cytoplasmic sequestration. Finally, a portion of p53 is localized to the mitochondria as part of the non-transcriptional apoptotic response. In this review we strive to present the most recent data on how the activity of p53 is regulated by its location.
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Affiliation(s)
- Aurora O'Brate
- Winship Cancer Institute, Emory University, 1365-C Clifton Road, N.E., Room C4078, Atlanta, GA 30322, USA
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25
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Melnikova VO, Bolshakov SV, Walker C, Ananthaswamy HN. Genomic alterations in spontaneous and carcinogen-induced murine melanoma cell lines. Oncogene 2004; 23:2347-56. [PMID: 14743208 DOI: 10.1038/sj.onc.1207405] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
We have conducted an analysis of genetic alterations in spontaneous murine melanoma cell line B16F0 and its two metastatic clones, B16F1 and B16F10 and the carcinogen-induced murine melanoma cell lines CM519, CM3205, and K1735. We found that unlike human melanomas, the murine melanoma cell lines did not have activating mutations in the Braf oncogene at exon 11 or 15. However, there were distinct patterns of alterations in the ras, Ink4a/Arf, and p53 genes in the two melanoma groups. In the spontaneous B16 melanoma cell lines, expression of p16Ink4a and p19Arf tumor suppressor proteins was lost as a consequence of a large deletion spanning Ink4a/Arf exons 1alpha, 1beta, and 2. In contrast, the carcinogen-induced melanoma cell lines expressed p16Ink4a but had inactivating mutations in either p19Arf (K1735) or p53 (CM519 and CM3205). Inactivation of p19Arf or p53 in carcinogen-induced melanomas was accompanied by constitutive activation of mitogen-activated protein kinases (MAPKs) and/or mutation-associated activation of N-ras. These results indicate that genetic alterations in p16Ink4a/p19Arf, p53 and ras-MAPK pathways can cooperate in the development of murine melanoma.
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Affiliation(s)
- Vladislava O Melnikova
- Department of Immunology, The University of Texas MD Anderson Cancer Center, PO Box 301402, Unit 902, Houston, TX 77030, USA
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26
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Abstract
Nuclear localization of p53 is essential for its tumor suppressor function. Here, we have identified Parc, a Parkin-like ubiquitin ligase, as a cytoplasmic anchor protein in p53-associated protein complexes. Parc directly interacts and forms a approximately 1 MDa complex with p53 in the cytoplasm of unstressed cells. In the absence of stress, inactivation of Parc induces nuclear localization of endogenous p53 and activates p53-dependent apoptosis. Overexpression of Parc promotes cytoplasmic sequestration of ectopic p53. Furthermore, abnormal cytoplasmic localization of p53 was observed in a number of neuroblastoma cell lines; RNAi-mediated reduction of endogenous Parc significantly sensitizes these neuroblastoma cells in the DNA damage response. These results reveal that Parc is a critical regulator in controlling p53 subcellular localization and subsequent function.
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Affiliation(s)
- Anatoly Y Nikolaev
- Institute for Cancer Genetics and Department of Pathology, College of Physicians and Surgeons, Columbia University, 1150 St. Nicholas Avenue, New York, NY 10032, USA
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27
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Gadéa G, Lapasset L, Gauthier-Rouvière C, Roux P. Regulation of Cdc42-mediated morphological effects: a novel function for p53. EMBO J 2002; 21:2373-82. [PMID: 12006490 PMCID: PMC126005 DOI: 10.1093/emboj/21.10.2373] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
The tumour suppressor functions of p53 that are important for its activity depend on its role as a cell cycle arrest mediator and apoptosis inducer. Here we identify a novel function for p53 in regulating cell morphology and movement. We investigated the overall effect of p53 on morphological changes induced by RhoA, Rac1 and Cdc42 GTPases in mouse embryonic fibroblasts (MEFs). Interestingly, p53 exerted a selective effect on Cdc42-mediated cell functions. (i) Both overexpression of wild-type p53 and activation of endogenous p53 counteracted Cdc42-induced filopodia formation. Conversely, p53-deficient MEFs exhibited constitutive membrane filopodia. Mechanistic studies indicate that p53 prevents the initiating steps of filopodia formation downstream of Cdc42. (ii) Over expression of p53 modulates cell spreading of MEFs on fibronectin. (iii) During cell migration, the reorientation of the Golgi apparatus in the direction of movement is abolished by wild-type p53 expression, thus preventing cell polarity. Our data demonstrate a previously uncharacterized role for p53 in regulating Cdc42-dependent cell effects that control actin cytoskeletal dynamics and cell movement. This novel function may contribute to p53 anti-tumour activity.
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Affiliation(s)
| | | | | | - Pierre Roux
- Centre de Recherche en Biochimie Macromoléculaire, CNRS UPR1086, IFR 24, 1919 route de Mende, F-34293 Montpellier cedex 5, France
Corresponding author e-mail:
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28
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Sim DLC, Yeo WM, Chow VTK. The novel human HUEL (C4orf1) protein shares homology with the DNA-binding domain of the XPA DNA repair protein and displays nuclear translocation in a cell cycle-dependent manner. Int J Biochem Cell Biol 2002; 34:487-504. [PMID: 11906820 DOI: 10.1016/s1357-2725(01)00156-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
We have previously isolated and characterized a novel human gene HUEL (C4orf1) that is ubiquitously expressed in a wide range of human fetal, adult tissues and cancer cell lines. HUEL maps to region 4p12-p13 within the short arm of chromosome 4 whose deletion is frequently associated with bladder and other carcinomas. Here we present the genomic organization, sizes and boundaries of exons and introns of HUEL. The GC-rich upstream genomic region and 5' untranslated region (UTR) together constitute a CpG island, a hallmark of housekeeping genes. The 3250 bp HUEL cDNA incorporates a 1704 bp ORF that translates into a hydrophilic protein of 568-amino acids (aa), detected as a band of approximately 70 kDa by Western blotting. We have isolated the murine homolog of HUEL which exhibits 89% nucleotide and 94% amino acid identity to its human counterpart. The HUEL protein shares significant homology with the minimal DNA-binding domain (DNA-BD) of the DNA repair protein encoded by the xeroderma pigmentosum group A (XPA) gene. Other notable features within HUEL include the putative nuclear receptor interaction motif, nuclear localization and export signals, zinc finger, leucine zipper and acidic domains. Mimosine-mediated cell cycle synchronization of PLC/PRF/5 liver cancer cells clearly portrayed translocation of HUEL into the nucleus specifically during the S phase of the cell cycle. Yeast two-hybrid experiments revealed interactions of HUEL with two partner proteins (designated HIPC and HIPB) bearing similarity to a mitotically phosphorylated protein and to reverse transcriptase. Co-immunoprecipitation assays validated the interaction between HUEL and HIPC proteins in mammalian cells. HUEL is likely to be an evolutionarily conserved, housekeeping gene that plays a role intimately linked with cellular replication, DNA synthesis and/or transcriptional regulation.
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Affiliation(s)
- Del L C Sim
- Human Genome Laboratory, Department of Microbiology, Faculty of Medicine, National University of Singapore, Kent Ridge 117597, Singapore
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29
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Okorokov AL, Rubbi CP, Metcalfe S, Milner J. The interaction of p53 with the nuclear matrix is mediated by F-actin and modulated by DNA damage. Oncogene 2002; 21:356-67. [PMID: 11821948 DOI: 10.1038/sj.onc.1205112] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2001] [Revised: 10/12/2001] [Accepted: 10/30/2001] [Indexed: 11/09/2022]
Abstract
The tumour suppressor protein p53 is localized in the cell nucleus where it serves to initiate cellular responses to a variety of stresses, particularly DNA damage and has the capacity to transactivate stress response genes. An emerging body of evidence indicates that its action is also exerted through direct protein-protein interactions. An approach to understanding p53 function has been to analyse its positioning in relation to nuclear structures and we have shown that p53 can associate with the nuclear matrix. A potential nuclear matrix component for this association is actin. Here we show that p53 interacts with nuclear F-actin and we map the domains involved in this interaction. Using fluorescence resonance energy transfer, we demonstrate that the partition of p53 between F-actin bound and unbound forms is not constant, but is modulated by the presence of DNA damage, which increases binding. Our results indicate that the dynamic interaction of p53 with the nuclear matrix has to be considered for a full understanding of the mechanisms of the p53-mediated cellular response to DNA damage.
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Affiliation(s)
- Andrei L Okorokov
- YCR P53 Research Group, Department of Biology, University of York, York, YO10 5DD, UK
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30
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Karmakar P, Natarajan AT, Poddar RK, Dasgupta UB. Induction of apoptosis by Phenothiazine derivatives in V79 cells. Toxicol Lett 2001; 125:19-28. [PMID: 11701219 DOI: 10.1016/s0378-4274(01)00411-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Phenothiazine derivatives chlorpromazine (cpz) and trifluoperazine (tfp) were found to induce apoptosis, abnormal cell cycle and expression of p53 in Chinese hamster lung fibroblast V79 cells. Both the drugs can induce apoptosis when cells are treated with drug at a concentration of 10 microg/ml within 4 h, as detected by propidium iodide staining and DNA fragmentation analysis. Flow cytometric analysis revealed that the apoptotic response is mediated by a loss of G(1) population of cells. In Western blot analysis, p21 is induced and p53 is accompanied by additional bands. Also indirect immunolabeling of single cells revealed that p21 is accumulated from cytoplasm into nucleus after the drug treatment and the intensities of p53 increased. Our findings demonstrate for the first time that phenothiazine derivatives, in addition to their cytotoxic effects, could induce apoptosis, an observation that has important clinical implications.
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Affiliation(s)
- P Karmakar
- Department of Biophysics, Molecular Biology & Genetics, 92, A.P.C. Road, 700 009, Calcutta, India.
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31
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A high constitutive level of NF-κB is necessary for the viability of mouse adenocarcinoma cells: A possible role of p53. Mol Biol 2000. [DOI: 10.1007/bf02759603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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32
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Jimenez GS, Khan SH, Stommel JM, Wahl GM. p53 regulation by post-translational modification and nuclear retention in response to diverse stresses. Oncogene 1999; 18:7656-65. [PMID: 10618705 DOI: 10.1038/sj.onc.1203013] [Citation(s) in RCA: 146] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
p53 activation by diverse stresses involves post-translational modifications that alter its structure and result in its nuclear accumulation. We will discuss several unresolved topics regarding p53 regulation which are currently under investigation. DNA damage is perhaps the best-studied stress which activates p53, and recent data implicate phosphorylation at N-terminal serine residues as critical in this process. We discuss recent data regarding the potential kinases which modify p53 and the possible role of the resulting phosphorylation events. By contrast, much less is understood about agents which disrupt the mitotic spindle. The cell cycle phase, induction signal, and biochemical mechanism of the reversible arrest induced by microtubule disruption are currently under investigation. Finally, a key event in response to any genotoxic stress is the accumulation of p53 in the nucleus. The factors which determine the steady state level of p53 are starting to be elucidated, but the mechanisms responsible for nuclear accumulation and nuclear export remain controversial. We discuss new studies revealing a mechanism for nuclear retention of p53, and the potential contributions of MDM2 to this process.
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Affiliation(s)
- G S Jimenez
- Gene Expression Laboratory, The Salk Institute, 10010 N. Torrey Pines Road, La Jolla, California, CA 92037, USA
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33
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Ku NO, Zhou X, Toivola DM, Omary MB. The cytoskeleton of digestive epithelia in health and disease. Am J Physiol Gastrointest Liver Physiol 1999; 277:G1108-37. [PMID: 10600809 DOI: 10.1152/ajpgi.1999.277.6.g1108] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 04/07/2023]
Abstract
The mammalian cell cytoskeleton consists of a diverse group of fibrillar elements that play a pivotal role in mediating a number of digestive and nondigestive cell functions, including secretion, absorption, motility, mechanical integrity, and mitosis. The cytoskeleton of higher-eukaryotic cells consists of three highly abundant major protein families: microfilaments (MF), microtubules (MT), and intermediate filaments (IF), as well as a growing number of associated proteins. Within digestive epithelia, the prototype members of these three protein families are actins, tubulins, and keratins, respectively. This review highlights the important structural, regulatory, functional, and unique features of the three major cytoskeletal protein groups in digestive epithelia. The emerging exciting biological aspects of these protein groups are their involvement in cell signaling via direct or indirect interaction with a growing list of associated proteins (MF, MT, IF), the identification of several disease-causing mutations (IF, MF), the functional role that they play in protection from environmental stresses (IF), and their functional integration via several linker proteins that bridge two or potentially all three of these groups together. The use of agents that target specific cytoskeletal elements as therapeutic modalities for digestive diseases offers potential unique areas of intervention that remain to be fully explored.
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Affiliation(s)
- N O Ku
- Department of Medicine, Veterans Affairs Palo Alto Health Care System, Palo Alto, California 94304, USA
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