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Halász H, Szatmári Z, Kovács K, Koppán M, Papp S, Szabó-Meleg E, Szatmári D. Changes of Ex Vivo Cervical Epithelial Cells Due to Electroporation with JMY. Int J Mol Sci 2023; 24:16863. [PMID: 38069185 PMCID: PMC10706833 DOI: 10.3390/ijms242316863] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Revised: 11/20/2023] [Accepted: 11/25/2023] [Indexed: 12/18/2023] Open
Abstract
The ionic environment within the nucleoplasm might diverge from the conditions found in the cytoplasm, potentially playing a role in the cellular stress response. As a result, it is conceivable that interactions of nuclear actin and actin-binding proteins (ABPs) with apoptosis factors may differ in the nucleoplasm and cytoplasm. The primary intracellular stress response is Ca2+ influx. The junctional mediating and regulating Y protein (JMY) is an actin-binding protein and has the capability to interact with the apoptosis factor p53 in a Ca2+-dependent manner, forming complexes that play a regulatory role in cytoskeletal remodelling and motility. JMY's presence is observed in both the cytoplasm and nucleoplasm. Here, we show that ex vivo ectocervical squamous cells subjected to electroporation with JMY protein exhibited varying morphological alterations. Specifically, the highly differentiated superficial and intermediate cells displayed reduced nuclear size. In inflamed samples, nuclear enlargement and simultaneous cytoplasmic reduction were observable and showed signs of apoptotic processes. In contrast, the less differentiated parabasal and metaplastic cells showed increased cytoplasmic activity and the formation of membrane protrusions. Surprisingly, in severe inflammation, vaginosis or ASC-US (Atypical Squamous Cells of Undetermined Significance), JMY appears to influence only the nuclear and perinuclear irregularities of differentiated cells, and cytoplasmic abnormalities still existed after the electroporation. Our observations can provide an appropriate basis for the exploration of the relationship between cytopathologically relevant morphological changes of epithelial cells and the function of ABPs. This is particularly important since ABPs are considered potential diagnostic and therapeutic biomarkers for both cancers and chronic inflammation.
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Affiliation(s)
- Henriett Halász
- Department of Biophysics, Medical School, University of Pécs, 7624 Pécs, Hungary; (H.H.); (E.S.-M.)
| | | | - Krisztina Kovács
- Department of Pathology, Medical School, University of Pécs, 7624 Pécs, Hungary;
| | | | - Szilárd Papp
- DaVinci Clinics, 7635 Pécs, Hungary; (M.K.); (S.P.)
| | - Edina Szabó-Meleg
- Department of Biophysics, Medical School, University of Pécs, 7624 Pécs, Hungary; (H.H.); (E.S.-M.)
| | - Dávid Szatmári
- Department of Biophysics, Medical School, University of Pécs, 7624 Pécs, Hungary; (H.H.); (E.S.-M.)
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2
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Rodriguez-Pastrana I, Birli E, Coutts AS. p53-dependent DNA repair during the DNA damage response requires actin nucleation by JMY. Cell Death Differ 2023:10.1038/s41418-023-01170-9. [PMID: 37142657 DOI: 10.1038/s41418-023-01170-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 04/14/2023] [Accepted: 04/20/2023] [Indexed: 05/06/2023] Open
Abstract
The tumour suppressor p53 is a nuclear transcription factor with key roles during DNA damage to enable a variety of cellular responses including cell cycle arrest, apoptosis and DNA repair. JMY is an actin nucleator and DNA damage-responsive protein whose sub-cellular localisation is responsive to stress and during DNA damage JMY undergoes nuclear accumulation. To gain an understanding of the wider role for nuclear JMY in transcriptional regulation, we performed transcriptomics to identify JMY-mediated changes in gene expression during the DNA damage response. We show that JMY is required for effective regulation of key p53 target genes involved in DNA repair, including XPC, XRCC5 (Ku80) and TP53I3 (PIG3). Moreover, JMY depletion or knockout leads to increased DNA damage and nuclear JMY requires its Arp2/3-dependent actin nucleation function to promote the clearance of DNA lesions. In human patient samples a lack of JMY is associated with increased tumour mutation count and in cells results in reduced cell survival and increased sensitivity to DNA damage response kinase inhibition. Collectively, we demonstrate that JMY enables p53-dependent DNA repair under genotoxic stress and suggest a role for actin in JMY nuclear activity during the DNA damage response.
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Affiliation(s)
- Ignacio Rodriguez-Pastrana
- School of Science and Technology, Department of Biosciences, Nottingham Trent University, Clifton Lane, Nottingham, NG11 8NS, UK
| | - Eleni Birli
- School of Science and Technology, Department of Biosciences, Nottingham Trent University, Clifton Lane, Nottingham, NG11 8NS, UK
- John van Geest Cancer Research Centre, Nottingham Trent University, Clifton Lane, Nottingham, NG11 8NS, UK
| | - Amanda S Coutts
- School of Science and Technology, Department of Biosciences, Nottingham Trent University, Clifton Lane, Nottingham, NG11 8NS, UK.
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3
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Campellone KG, Lebek NM, King VL. Branching out in different directions: Emerging cellular functions for the Arp2/3 complex and WASP-family actin nucleation factors. Eur J Cell Biol 2023; 102:151301. [PMID: 36907023 DOI: 10.1016/j.ejcb.2023.151301] [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: 08/19/2022] [Revised: 02/07/2023] [Accepted: 02/25/2023] [Indexed: 03/06/2023] Open
Abstract
The actin cytoskeleton impacts practically every function of a eukaryotic cell. Historically, the best-characterized cytoskeletal activities are in cell morphogenesis, motility, and division. The structural and dynamic properties of the actin cytoskeleton are also crucial for establishing, maintaining, and changing the organization of membrane-bound organelles and other intracellular structures. Such activities are important in nearly all animal cells and tissues, although distinct anatomical regions and physiological systems rely on different regulatory factors. Recent work indicates that the Arp2/3 complex, a broadly expressed actin nucleator, drives actin assembly during several intracellular stress response pathways. These newly described Arp2/3-mediated cytoskeletal rearrangements are coordinated by members of the Wiskott-Aldrich Syndrome Protein (WASP) family of actin nucleation-promoting factors. Thus, the Arp2/3 complex and WASP-family proteins are emerging as crucial players in cytoplasmic and nuclear activities including autophagy, apoptosis, chromatin dynamics, and DNA repair. Characterizations of the functions of the actin assembly machinery in such stress response mechanisms are advancing our understanding of both normal and pathogenic processes, and hold great promise for providing insights into organismal development and interventions for disease.
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Affiliation(s)
- Kenneth G Campellone
- Department of Molecular and Cell Biology, Institute for Systems Genomics; University of Connecticut; Storrs, CT, USA.
| | - Nadine M Lebek
- Department of Molecular and Cell Biology, Institute for Systems Genomics; University of Connecticut; Storrs, CT, USA
| | - Virginia L King
- Department of Molecular and Cell Biology, Institute for Systems Genomics; University of Connecticut; Storrs, CT, USA
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4
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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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5
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The emerging roles of circular RNAs in vessel co-option and vasculogenic mimicry: clinical insights for anti-angiogenic therapy in cancers. Cancer Metastasis Rev 2021; 41:173-191. [PMID: 34664157 DOI: 10.1007/s10555-021-10000-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Accepted: 10/12/2021] [Indexed: 12/20/2022]
Abstract
Unexpected resistance to anti-angiogenic treatment prompted the investigation of non-angiogenic tumor processes. Vessel co-option (VC) and vasculogenic mimicry (VM) are recognized as primary non-angiogenic mechanisms. In VC, cancer cells utilize pre-existing blood vessels for support, whereas in VM, cancer cells channel and provide blood flow to rapidly growing tumors. Both processes have been implicated in the development of tumor and resistance to anti-angiogenic drugs in many tumor types. The morphology, but rare molecular alterations have been investigated in VC and VM. There is a pressing need to better understand the underlying cellular and molecular mechanisms. Here, we review the emerging circular RNA (circRNA)-mediated regulation of non-angiogenic processes, VC and VM.
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6
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The actin nucleation factors JMY and WHAMM enable a rapid Arp2/3 complex-mediated intrinsic pathway of apoptosis. PLoS Genet 2021; 17:e1009512. [PMID: 33872315 PMCID: PMC8084344 DOI: 10.1371/journal.pgen.1009512] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 04/29/2021] [Accepted: 03/28/2021] [Indexed: 01/02/2023] Open
Abstract
The actin cytoskeleton is a well-known player in most vital cellular processes, but comparably little is understood about how the actin assembly machinery impacts programmed cell death pathways. In the current study, we explored roles for the human Wiskott-Aldrich Syndrome Protein (WASP) family of actin nucleation factors in DNA damage-induced apoptosis. Inactivation of each WASP-family gene revealed that two of them, JMY and WHAMM, are necessary for rapid apoptotic responses. JMY and WHAMM participate in a p53-dependent cell death pathway by enhancing mitochondrial permeabilization, initiator caspase cleavage, and executioner caspase activation. JMY-mediated apoptosis requires actin nucleation via the Arp2/3 complex, and actin filaments are assembled in cytoplasmic territories containing clusters of cytochrome c and active caspase-3. The loss of JMY additionally results in significant changes in gene expression, including upregulation of the WHAMM-interacting G-protein RhoD. Depletion or deletion of RHOD increases cell death, suggesting that RhoD normally contributes to cell survival. These results give rise to a model in which JMY and WHAMM promote intrinsic cell death responses that can be opposed by RhoD.
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7
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The HIF1α/JMY pathway promotes glioblastoma stem-like cell invasiveness after irradiation. Sci Rep 2020; 10:18742. [PMID: 33128011 PMCID: PMC7603339 DOI: 10.1038/s41598-020-75300-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Accepted: 10/13/2020] [Indexed: 01/28/2023] Open
Abstract
Human glioblastoma (GBM) is the most common primary malignant brain tumor. A minor subpopulation of cancer cells, known as glioma stem-like cells (GSCs), are thought to play a major role in tumor relapse due to their stem cell-like properties, their high resistance to conventional treatments and their high invasion capacity. We show that ionizing radiation specifically enhances the motility and invasiveness of human GSCs through the stabilization and nuclear accumulation of the hypoxia-inducible factor 1α (HIF1α), which in turn transcriptionally activates the Junction-mediating and regulatory protein (JMY). Finally, JMY accumulates in the cytoplasm where it stimulates GSC migration via its actin nucleation-promoting activity. Targeting JMY could thus open the way to the development of new therapeutic strategies to improve the efficacy of radiotherapy and prevent glioma recurrence.
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8
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Lin ZL, Li YH, Jin YX, Kim NH. A Maternal Transcription Factor, Junction Mediating and Regulatory
Protein is Required for Preimplantation Development in the Mouse. Dev Reprod 2019; 23:285-295. [PMID: 31660455 PMCID: PMC6812975 DOI: 10.12717/dr.2019.23.3.285] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 08/05/2019] [Accepted: 08/29/2019] [Indexed: 11/21/2022]
Abstract
Junction-mediating and regulatory protein (JMY) is a regulator of both
transcription and actin filament assembly. The actin-regulatory activity of JMY
is based on a cluster of three actin-binding Wiskott-Aldrich syndrome protein
homology 2 (WH2) domains that nucleate actin filaments directly and promote
nucleation of the Arp2/3 complex. In addition to these activities, we examined
the activity of JMY generation in early embryo of mice carrying mutations in the
JMY gene by CRISPR/Cas9 mediated genome engineering. We demonstrated that JMY
protein shuttled expression between the cytoplasm and the nucleus. Knockout of
exon 2, CA (central domain and Arp2/3-binding acidic domain) and NLS-2 (nuclear
localization signal domain) on the JMY gene by CRISPR/Cas9
system was effective and markedly impeded embryonicdevelopment. Additionally, it
impaired transcription and zygotic genome activation (ZGA)-related genes. These
results suggest that JMY acts as a transcription factor, which is essential for
the early embryonic development in mice.
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Affiliation(s)
- Zi-Li Lin
- College of Animal Sciences, Jilin
University, Changchun, China
- School of Life Sciences, Tsinghua
University, Beijing 100084, China
| | - Ying-Hua Li
- Department of Animal Sciences, Yanbian
University, Yanji, Jilin Province,
China
| | - Yong-Xun Jin
- College of Animal Sciences, Jilin
University, Changchun, China
- Corresponding Author : Nam-Hyung Kim, Ph.D.,
Department of Animal Sciences, Chungbuk National University, Cheongju 28644,
Korea. Tel: +82-43-261-2546, E-mail:
, Yong-Xun Jin, College of Animal
Sciences, Jilin University, Changchun, China. Tel:
+86-431-8516-6316, E-mail:
| | - Nam-Hyung Kim
- College of Animal Sciences, Jilin
University, Changchun, China
- Department of Animal Sciences, Chungbuk National
University, Cheongju 28644, Korea
- Corresponding Author : Nam-Hyung Kim, Ph.D.,
Department of Animal Sciences, Chungbuk National University, Cheongju 28644,
Korea. Tel: +82-43-261-2546, E-mail:
, Yong-Xun Jin, College of Animal
Sciences, Jilin University, Changchun, China. Tel:
+86-431-8516-6316, E-mail:
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9
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Naldi A, Hernandez C, Abou-Jaoudé W, Monteiro PT, Chaouiya C, Thieffry D. Logical Modeling and Analysis of Cellular Regulatory Networks With GINsim 3.0. Front Physiol 2018; 9:646. [PMID: 29971008 PMCID: PMC6018412 DOI: 10.3389/fphys.2018.00646] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Accepted: 05/11/2018] [Indexed: 11/13/2022] Open
Abstract
The logical formalism is well adapted to model large cellular networks, in particular when detailed kinetic data are scarce. This tutorial focuses on this well-established qualitative framework. Relying on GINsim (release 3.0), a software implementing this formalism, we guide the reader step by step toward the definition, the analysis and the simulation of a four-node model of the mammalian p53-Mdm2 network.
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Affiliation(s)
- Aurélien Naldi
- Computational Systems Biology Team, Institut de Biologie de l'Ecole Normale Supérieure (IBENS), École Normale Supérieure, Centre National de la Recherche Scientifique, Institut National de la Sante et de la Recherche Médicale, PSL Université, Paris, France
| | - Céline Hernandez
- Computational Systems Biology Team, Institut de Biologie de l'Ecole Normale Supérieure (IBENS), École Normale Supérieure, Centre National de la Recherche Scientifique, Institut National de la Sante et de la Recherche Médicale, PSL Université, Paris, France
| | - Wassim Abou-Jaoudé
- Computational Systems Biology Team, Institut de Biologie de l'Ecole Normale Supérieure (IBENS), École Normale Supérieure, Centre National de la Recherche Scientifique, Institut National de la Sante et de la Recherche Médicale, PSL Université, Paris, France
| | - Pedro T. Monteiro
- INESC-ID, Instituto Superior Técnico, University of Lisbon, Lisbon, Portugal
| | | | - Denis Thieffry
- Computational Systems Biology Team, Institut de Biologie de l'Ecole Normale Supérieure (IBENS), École Normale Supérieure, Centre National de la Recherche Scientifique, Institut National de la Sante et de la Recherche Médicale, PSL Université, Paris, France
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10
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The Role of JMY in p53 Regulation. Cancers (Basel) 2018; 10:cancers10060173. [PMID: 29857553 PMCID: PMC6025294 DOI: 10.3390/cancers10060173] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Revised: 05/10/2018] [Accepted: 05/10/2018] [Indexed: 11/17/2022] Open
Abstract
Following the event of DNA damage, the level of tumour suppressor protein p53 increases inducing either cell cycle arrest or apoptosis. Junctional Mediating and Regulating Y protein (JMY) is a transcription co-factor involved in p53 regulation. In event of DNA damage, JMY levels also upregulate in the nucleus where JMY forms a co-activator complex with p300/CREB-binding protein (p300/CBP), Apoptosis-stimulating protein of p53 (ASPP) and Stress responsive activator of p53 (Strap). This co-activator complex then binds to and increases the ability of p53 to induce transcription of proteins triggering apoptosis but not cell cycle arrest. This then suggests that the increase of JMY levels due to DNA damage putatively "directs" p53 activity toward triggering apoptosis. JMY expression is also linked to increased cell motility as it: (1) downregulates the expression of adhesion molecules of the Cadherin family and (2) induces actin nucleation, making cells less adhesive and more mobile, favouring metastasis. All these characteristics taken together imply that JMY possesses both tumour suppressive and tumour metastasis promoting capabilities.
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11
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Giono LE, Resnick-Silverman L, Carvajal LA, St Clair S, Manfredi JJ. Mdm2 promotes Cdc25C protein degradation and delays cell cycle progression through the G2/M phase. Oncogene 2017; 36:6762-6773. [PMID: 28806397 DOI: 10.1038/onc.2017.254] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Revised: 06/15/2017] [Accepted: 06/27/2017] [Indexed: 12/16/2022]
Abstract
Upon different types of stress, the gene encoding the mitosis-promoting phosphatase Cdc25C is transcriptionally repressed by p53, contributing to p53's enforcement of a G2 cell cycle arrest. In addition, Cdc25C protein stability is also decreased following DNA damage. Mdm2, another p53 target gene, encodes a ubiquitin ligase that negatively regulates p53 levels by ubiquitination. Ablation of Mdm2 by siRNA led to an increase in p53 protein and repression of Cdc25C gene expression. However, Cdc25C protein levels were actually increased following Mdm2 depletion. Mdm2 is shown to negatively regulate Cdc25C protein levels by reducing its half-life independently of the presence of p53. Further, Mdm2 physically interacts with Cdc25C and promotes its degradation through the proteasome in a ubiquitin-independent manner. Either Mdm2 overexpression or Cdc25C downregulation delays cell cycle progression through the G2/M phase. Thus, the repression of the Cdc25C promoter by p53, together with p53-dependent induction of Mdm2 and subsequent degradation of Cdc25C, could provide a dual mechanism by which p53 can enforce and maintain a G2/M cell cycle arrest.
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Affiliation(s)
- L E Giono
- Department of Oncological Sciences and Graduate School of Biological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - L Resnick-Silverman
- Department of Oncological Sciences and Graduate School of Biological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - L A Carvajal
- Department of Oncological Sciences and Graduate School of Biological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - S St Clair
- Department of Oncological Sciences and Graduate School of Biological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - J J Manfredi
- Department of Oncological Sciences and Graduate School of Biological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
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12
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Abstract
Although most people still associate actin mainly with the cytoskeleton, several lines of evidence, with the earliest studies dating back to decades ago, have emphasized the importance of actin also inside the cell nucleus. Actin has been linked to many gene expression processes from gene activation to chromatin remodeling, but also to maintenance of genomic integrity and intranuclear movement of chromosomes and chromosomal loci. Recent advances in visualizing different forms and dynamic properties of nuclear actin have clearly advanced our understanding of the basic concepts by which actin operates in the nucleus. In this chapter we address the different breakthroughs in nuclear actin studies, as well as discuss the regulation nuclear actin and the importance of nuclear actin dynamics in relation to its different nuclear functions. Our aim is to highlight the fact that actin should be considered as an essential component of the cell nucleus, and its nuclear actions should be taken into account also in experiments on cytoplasmic actin networks.
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Affiliation(s)
- Tiina Viita
- Program in Cell and Molecular Biology, Institute of Biotechnology, University of Helsinki, 56, Helsinki, Finland
| | - Maria K Vartiainen
- Program in Cell and Molecular Biology, Institute of Biotechnology, University of Helsinki, 56, Helsinki, Finland.
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13
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Giunti L, Buccoliero AM, Pantaleo M, Lucchesi M, Provenzano A, Palazzo V, Guarducci S, Guidi M, Genitori L, Zuffardi O, Sardi I, Giglio S. Molecular characterization of paediatric glioneuronal tumours with neuropil-like islands: a genome-wide copy number analysis. Am J Cancer Res 2016; 6:2910-2918. [PMID: 28042510 PMCID: PMC5199764] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Accepted: 07/23/2016] [Indexed: 06/06/2023] Open
Abstract
Paediatric glioneuronal tumour with neuropil-like islands (GTNI) is a rare neoplasm of neuronal differentiation and diffusely infiltrating astroglial and oligodendrocyte-like components. The 2007 World Health Organization classification of central nervous system tumours considered it as a pattern variation of anaplastic astrocytoma. There are few data on paediatric GTNI probably both for their rarity and variable clinical aggressiveness. We studied by SNP/CGH array four tumour samples of GTNI from two males and two females (one new-born and three children aged from 4 to 8 years), in order to identify any possible common genomic alteration. All patients received chemo- and radiotherapy after their surgical treatment. No genomic instability nor recurrent alterations have been demonstrated in two of our GTNI cases. In the remaining two, we detected a mosaic trisomy 8 (15-20%) in one case, and an amplification at 5q14.1 involving DMGDH (partially), BHMT2 and BHMT genes, with the distal breakpoint falling at 23 Kbp from the 5'UTR of JMY, a p53 cofactor. Although the smallness of the sample impairs any clinical-histological correlation, GTNI appear different at the molecular level, with genomic imbalances playing a possible role in at least part of them. Our work gives an important contribution in knowledge and classification of this family of tumours.
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Affiliation(s)
- Laura Giunti
- Medical Genetics Unit, Meyer Children’s University HospitalViale Pieraccini 2450139, Florence, Italy
| | - Anna Maria Buccoliero
- Anatomic Pathology Unit, Meyer Children’s University HospitalViale Pieraccini 2450139, Florence, Italy
| | - Marilena Pantaleo
- Medical Genetics Unit, Meyer Children’s University HospitalViale Pieraccini 2450139, Florence, Italy
| | - Maurizio Lucchesi
- Neuro-Oncology Unit, Department of Pediatric Oncology, Meyer Children’s University HospitalViale Pieraccini 2450139, Florence, Italy
| | - Aldesia Provenzano
- Medical Genetics Unit, Department of Clinical and Experimental Biomedical Sciences “Mario Serio”, University of FlorenceViale Morgagni 5050134, Florence, Italy (S.G.)
| | - Viviana Palazzo
- Medical Genetics Unit, Department of Clinical and Experimental Biomedical Sciences “Mario Serio”, University of FlorenceViale Morgagni 5050134, Florence, Italy (S.G.)
| | - Silvia Guarducci
- Medical Genetics Unit, Meyer Children’s University HospitalViale Pieraccini 2450139, Florence, Italy
| | - Milena Guidi
- Neuro-Oncology Unit, Department of Pediatric Oncology, Meyer Children’s University HospitalViale Pieraccini 2450139, Florence, Italy
| | - Lorenzo Genitori
- Neurosurgery Unit, Department of Neuroscience, Meyer Children’s University HospitalViale Pieraccini 2450139, Florence, Italy
| | - Orsetta Zuffardi
- Department of Molecular Medicine, University of PaviaViale Forlanini 1427100, Pavia, Italy
| | - Iacopo Sardi
- Neuro-Oncology Unit, Department of Pediatric Oncology, Meyer Children’s University HospitalViale Pieraccini 2450139, Florence, Italy
| | - Sabrina Giglio
- Medical Genetics Unit, Meyer Children’s University HospitalViale Pieraccini 2450139, Florence, Italy
- Medical Genetics Unit, Department of Clinical and Experimental Biomedical Sciences “Mario Serio”, University of FlorenceViale Morgagni 5050134, Florence, Italy (S.G.)
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14
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Gentile G, Ceccarelli M, Micheli L, Tirone F, Cavallaro S. Functional Genomics Identifies Tis21-Dependent Mechanisms and Putative Cancer Drug Targets Underlying Medulloblastoma Shh-Type Development. Front Pharmacol 2016; 7:449. [PMID: 27965576 PMCID: PMC5127835 DOI: 10.3389/fphar.2016.00449] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Accepted: 11/09/2016] [Indexed: 12/11/2022] Open
Abstract
We have recently generated a novel medulloblastoma (MB) mouse model with activation of the Shh pathway and lacking the MB suppressor Tis21 (Patched1+/-/Tis21KO ). Its main phenotype is a defect of migration of the cerebellar granule precursor cells (GCPs). By genomic analysis of GCPs in vivo, we identified as drug target and major responsible of this defect the down-regulation of the promigratory chemokine Cxcl3. Consequently, the GCPs remain longer in the cerebellum proliferative area, and the MB frequency is enhanced. Here, we further analyzed the genes deregulated in a Tis21-dependent manner (Patched1+/-/Tis21 wild-type vs. Ptch1+/-/Tis21 knockout), among which are a number of down-regulated tumor inhibitors and up-regulated tumor facilitators, focusing on pathways potentially involved in the tumorigenesis and on putative new drug targets. The data analysis using bioinformatic tools revealed: (i) a link between the Shh signaling and the Tis21-dependent impairment of the GCPs migration, through a Shh-dependent deregulation of the clathrin-mediated chemotaxis operating in the primary cilium through the Cxcl3-Cxcr2 axis; (ii) a possible lineage shift of Shh-type GCPs toward retinal precursor phenotype, i.e., the neural cell type involved in group 3 MB; (iii) the identification of a subset of putative drug targets for MB, involved, among the others, in the regulation of Hippo signaling and centrosome assembly. Finally, our findings define also the role of Tis21 in the regulation of gene expression, through epigenetic and RNA processing mechanisms, influencing the fate of the GCPs.
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Affiliation(s)
- Giulia Gentile
- Institute of Neurological Sciences, National Research Council Catania, Italy
| | - Manuela Ceccarelli
- Institute of Cell Biology and Neurobiology, National Research Council, Fondazione Santa Lucia Rome, Italy
| | - Laura Micheli
- Institute of Cell Biology and Neurobiology, National Research Council, Fondazione Santa Lucia Rome, Italy
| | - Felice Tirone
- Institute of Cell Biology and Neurobiology, National Research Council, Fondazione Santa Lucia Rome, Italy
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15
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Coutts AS, La Thangue NB. Regulation of actin nucleation and autophagosome formation. Cell Mol Life Sci 2016; 73:3249-63. [PMID: 27147468 PMCID: PMC4967107 DOI: 10.1007/s00018-016-2224-z] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Revised: 03/21/2016] [Accepted: 04/08/2016] [Indexed: 01/08/2023]
Abstract
Autophagy is a process of self-eating, whereby cytosolic constituents are enclosed by a double-membrane vesicle before delivery to the lysosome for degradation. This is an important process which allows for recycling of nutrients and cellular components and thus plays a critical role in normal cellular homeostasis as well as cell survival during stresses such as starvation or hypoxia. A large number of proteins regulate various stages of autophagy in a complex and still incompletely understood series of events. In this review, we will discuss recent studies which provide a growing body of evidence that actin dynamics and proteins that influence actin nucleation play an important role in the regulation of autophagosome formation and maturation.
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Affiliation(s)
- Amanda S Coutts
- Laboratory of Cancer Biology, Medical Sciences Division, Department of Oncology, University of Oxford, Old Road Campus Research Building, Old Road Campus, Off Roosevelt Drive, Oxford, OX3 7DQ, UK
| | - Nicholas B La Thangue
- Laboratory of Cancer Biology, Medical Sciences Division, Department of Oncology, University of Oxford, Old Road Campus Research Building, Old Road Campus, Off Roosevelt Drive, Oxford, OX3 7DQ, UK.
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16
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Verboon JM, Sugumar B, Parkhurst SM. Wiskott-Aldrich syndrome proteins in the nucleus: aWASH with possibilities. Nucleus 2016; 6:349-59. [PMID: 26305109 PMCID: PMC4915506 DOI: 10.1080/19491034.2015.1086051] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Actin and proteins that regulate its dynamics or interactions have well-established roles in the cytoplasm where they function as key components of the cytoskeleton to control diverse processes, including cellular infrastructure, cellular motility, cell signaling, and vesicle transport. Recent work has also uncovered roles for actin and its regulatory proteins in the nucleus, primarily in mechanisms governing gene expression. The Wiskott Aldrich Syndrome (WAS) family of proteins, comprising the WASP/N-WASP, SCAR/WAVE, WHAMM/JMY/WHAMY, and WASH subfamilies, function in the cytoplasm where they activate the Arp2/3 complex to form branched actin filaments. WAS proteins are present in the nucleus and have been implicated as transcriptional regulators. We found that Drosophila Wash, in addition to transcriptional effects, is involved in global nuclear architecture. Here we summarize the regulation and function of nuclear WAS proteins, and highlight how our work with Wash expands the possibilities for the functions of these proteins in the nucleus.
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Affiliation(s)
- Jeffrey M Verboon
- a Division of Basic Sciences; Fred Hutchinson Cancer Research Center ; Seattle , WA USA
| | - Bina Sugumar
- a Division of Basic Sciences; Fred Hutchinson Cancer Research Center ; Seattle , WA USA
| | - Susan M Parkhurst
- a Division of Basic Sciences; Fred Hutchinson Cancer Research Center ; Seattle , WA USA
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17
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Steffen A, Stradal TEB, Rottner K. Signalling Pathways Controlling Cellular Actin Organization. Handb Exp Pharmacol 2016; 235:153-178. [PMID: 27757765 DOI: 10.1007/164_2016_35] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The actin cytoskeleton is essential for morphogenesis and virtually all types of cell shape changes. Reorganization is per definition driven by continuous disassembly and re-assembly of actin filaments, controlled by major, ubiquitously operating machines. These are specifically employed by the cell to tune its activities in accordance with respective environmental conditions or to satisfy specific needs.Here we sketch some fundamental signalling pathways established to contribute to the reorganization of specific actin structures at the plasma membrane. Rho-family GTPases are at the core of these pathways, and dissection of their precise contributions to actin reorganization in different cell types and tissues will thus continue to improve our understanding of these important signalling nodes. Furthermore, we will draw your attention to the emerging theme of actin reorganization on intracellular membranes, its functional relation to Rho-GTPase signalling, and its relevance for the exciting phenomenon autophagy.
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Affiliation(s)
- Anika Steffen
- Department of Cell Biology, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124, Braunschweig, Germany
| | - Theresia E B Stradal
- Department of Cell Biology, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124, Braunschweig, Germany.
| | - Klemens Rottner
- Department of Cell Biology, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124, Braunschweig, Germany.,Zoological Institute, Technische Universität Braunschweig, Spielmannstrasse 7, 38106, Braunschweig, Germany
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18
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Patnaik S, George SP, Pham E, Roy S, Singh K, Mariadason JM, Khurana S. By moonlighting in the nucleus, villin regulates epithelial plasticity. Mol Biol Cell 2015; 27:535-48. [PMID: 26658611 PMCID: PMC4751603 DOI: 10.1091/mbc.e15-06-0453] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Accepted: 11/30/2015] [Indexed: 12/02/2022] Open
Abstract
Nuclear villin regulates the expression and activity of Slug, a key transcriptional regulator of epithelial–mesenchymal transition, by directly interacting with its transcriptional corepressor, ZBRK1. Villin accumulates in the nucleus during wound repair, and altering the cellular microenvironment by hypoxia increases the nuclear villin. Villin is a tissue-specific, actin-binding protein involved in the assembly and maintenance of microvilli in polarized epithelial cells. Conversely, villin is also linked with the loss of epithelial polarity and gain of the mesenchymal phenotype in migrating, invasive cells. In this study, we describe for the first time how villin can switch between these disparate functions to change tissue architecture by moonlighting in the nucleus. Our study reveals that the moonlighting function of villin in the nucleus may play an important role in tissue homeostasis and disease. Villin accumulates in the nucleus during wound repair, and altering the cellular microenvironment by inducing hypoxia increases the nuclear accumulation of villin. Nuclear villin is also associated with mouse models of tumorigenesis, and a systematic analysis of a large cohort of colorectal cancer specimens confirmed the nuclear distribution of villin in a subset of tumors. Our study demonstrates that nuclear villin regulates epithelial–mesenchymal transition (EMT). Altering the nuclear localization of villin affects the expression and activity of Slug, a key transcriptional regulator of EMT. In addition, we find that villin directly interacts with a transcriptional corepressor and ligand of the Slug promoter, ZBRK1. The outcome of this study underscores the role of nuclear villin and its binding partner ZBRK1 in the regulation of EMT and as potential new therapeutic targets to inhibit tumorigenesis.
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Affiliation(s)
- Srinivas Patnaik
- Department of Biology and Biochemistry, University of Houston, Houston, TX 77204
| | - Sudeep P George
- Department of Biology and Biochemistry, University of Houston, Houston, TX 77204
| | - Eric Pham
- Department of Biology and Biochemistry, University of Houston, Houston, TX 77204
| | - Swati Roy
- Department of Biology and Biochemistry, University of Houston, Houston, TX 77204
| | - Kanchan Singh
- Department of Biology and Biochemistry, University of Houston, Houston, TX 77204
| | - John M Mariadason
- Olivia Newton-John Cancer Research Institute, La Trobe University School of Cancer Medicine, Melbourne, VIC 3084, Australia
| | - Seema Khurana
- Department of Biology and Biochemistry, University of Houston, Houston, TX 77204 Baylor College of Medicine, Houston, TX 77030
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19
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Abstract
Autophagy is a catabolic process whereby cytosolic components and organelles are degraded to recycle key cellular materials. It is a constitutive process required for proper tissue homoeostasis but can be rapidly regulated by a variety of stimuli (for example, nutrient starvation and chemotherapeutic agents). JMY is a DNA damage-responsive p53 cofactor and actin nucleator important for cell survival and motility. Here we show that JMY regulates autophagy through its actin nucleation activity. JMY contains an LC3-interacting region, which is necessary to target JMY to the autophagosome where it enhances the autophagy maturation process. In autophagosomes, the integrity of the WH2 domains allows JMY to promote actin nucleation, which is required for efficient autophagosome formation. Thus our results establish a direct role for actin nucleation mediated by WH2 domain proteins that reside at the autophagosome. Autophagy is a catabolic process whereby cellular components are degraded by the autophagosome, but the role of the actin cytoskeleton is not clear. Here Coutts and La Thangue show that the actin nucleator JMY is recruited to the autophagosome via binding LC3, and promotes actin nucleation that is required for autophagosome maturation.
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Affiliation(s)
- Amanda S Coutts
- Laboratory of Cancer Biology, Department of Oncology, Medical Sciences Division, University of Oxford, Old Road Campus Research Building, Old Road Campus, off Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Nicholas B La Thangue
- Laboratory of Cancer Biology, Department of Oncology, Medical Sciences Division, University of Oxford, Old Road Campus Research Building, Old Road Campus, off Roosevelt Drive, Oxford OX3 7DQ, UK
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20
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Lin ZL, Cui XS, Namgoong S, Kim NH. Junction-mediating and regulatory protein (JMY) is essential for early porcine embryonic development. J Reprod Dev 2015; 61:361-7. [PMID: 26052154 PMCID: PMC4623140 DOI: 10.1262/jrd.2015-021] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Junction-mediating and regulatory protein (JMY) is a regulator of both transcription and actin filament assembly. JMY is a critical nucleation-promoting factor (NPF); however, its role in the development of mammalian embryos is poorly understood. In the current study, we investigated the functional roles of the NPF JMY in porcine embryos. Porcine embryos expressed JMY mRNA and protein, and JMY protein moved from the cytoplasm to the nucleus at later embryonic developmental stages. Knockdown of JMY by RNA interference markedly decreased the rate of blastocyst development, validating its role in the development of porcine embryos. Furthermore, injection of JMY dsRNA also impaired actin and Arp2 expression, and co-injection of actin and Arp2 mRNA partially rescued blastocyst development. Taken together, our results show that the NPF JMY is involved in the development of porcine embryos by regulating the NPF-Arp2-actin pathway.
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Affiliation(s)
- Zi Li Lin
- Department of Animal Sciences, Chungbuk National University, Cheongju, Republic of Korea
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21
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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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22
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Adighibe O, Turley H, Leek R, Harris A, Coutts AS, La Thangue N, Gatter K, Pezzella F. JMY protein, a regulator of P53 and cytoplasmic actin filaments, is expressed in normal and neoplastic tissues. Virchows Arch 2014; 465:715-22. [PMID: 25280461 DOI: 10.1007/s00428-014-1660-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Revised: 09/18/2014] [Accepted: 09/23/2014] [Indexed: 01/04/2023]
Abstract
JMY is a p300-binding protein with dual action: by enhancing P53 transcription in the nucleus, it plays an important role in the cellular response to DNA damage, while by promoting actin filament assembly in the cytoplasm; it induces cell motility in vitro. Therefore, it has been argued that, depending of the cellular setting, it might act either as tumor suppressor or as oncogene. In order to further determine its relevance to human cancer, we produced the monoclonal antibody HMY 117 against a synthetic peptide from the N-terminus region and characterized it on two JMY positive cell lines, MCF7 and HeLa, wild type and after transfection with siRNA to switch off JMY expression. JMY was expressed in normal tissues and heterogeneously in different tumor types, with close correlation between cytoplasmic and nuclear expression. Most noticeable was the loss of expression in some infiltrating carcinomas compared to normal tissue and in in situ carcinomas of the breast, which is consistent with a putative suppressor role. However, as in lymph node metastases, expression of JMY was higher than in primary colorectal and head and neck carcinomas, it might also have oncogenic properties depending on the cellular context by increasing motility and metastatic potential.
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Affiliation(s)
- Omanma Adighibe
- Nuffield Division of Clinical Laboratory Science, Radcliffe Department of Medicine, University of Oxford, John Radcliffe Hospital, Oxford, UK
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23
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Lin Z, Xu YN, Namgoong S, Kim NH. JMY functions as actin nucleation-promoting factor and mediator for p53-mediated DNA damage in porcine oocytes. PLoS One 2014; 9:e109385. [PMID: 25279558 PMCID: PMC4184845 DOI: 10.1371/journal.pone.0109385] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2014] [Accepted: 09/10/2014] [Indexed: 01/04/2023] Open
Abstract
Junction-mediating and regulatory protein(JMY) is a multifunctional protein with roles in the transcriptional co-activation of p53 and the regulation of actin nucleation promoting factors and, hence, cell migration; however, its role in the maturation of porcine oocytes is unclear. In the current study, we investigated functional roles of JMY in porcine oocytes. Porcine oocytes expressed JMY mRNA and protein, and the mRNA expression level decreased during oocyte maturation. Knockdown of JMY by RNA interference decreased the rate of polar body extrusion, validating its role in the asymmetric division of porcine oocytes. JMY knockdown also down-regulated the mRNA and protein levels of actin and Arp2/3. Furthermore, JMY accumulated in the nucleus in response to DNA damage, and JMY knockdown suppressed DNA damage-mediated p53 activation. In conclusion, our results show that JMY has important roles in oocyte maturation as a regulator of actin nucleation-promoting factors and an activator of p53 during DNA damage during DNA damages in porcine oocytes.
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Affiliation(s)
- Zili Lin
- Department of Animal Sciences, Chungbuk National University, Cheongju, Korea
| | - Yong-Nan Xu
- Department of Animal Sciences, Chungbuk National University, Cheongju, Korea
| | - Suk Namgoong
- Department of Animal Sciences, Chungbuk National University, Cheongju, Korea
- * E-mail: (NHK); (SN)
| | - Nam-Hyung Kim
- Department of Animal Sciences, Chungbuk National University, Cheongju, Korea
- * E-mail: (NHK); (SN)
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24
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Gu D, Wang S, Kuiatse I, Wang H, He J, Dai Y, Jones RJ, Bjorklund CC, Yang J, Grant S, Orlowski RZ. Inhibition of the MDM2 E3 Ligase induces apoptosis and autophagy in wild-type and mutant p53 models of multiple myeloma, and acts synergistically with ABT-737. PLoS One 2014; 9:e103015. [PMID: 25181509 PMCID: PMC4151993 DOI: 10.1371/journal.pone.0103015] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2014] [Accepted: 06/25/2014] [Indexed: 02/05/2023] Open
Abstract
Intracellular proteolytic pathways have been validated as rational targets in multiple myeloma with the approval of two proteasome inhibitors in this disease, and with the finding that immunomodulatory agents work through an E3 ubiquitin ligase containing Cereblon. Another E3 ligase that could be a rational target is the murine double minute (MDM) 2 protein, which plays a role in p53 turnover. A novel inhibitor of this complex, MI-63, was found to induce apoptosis in p53 wild-type myeloma models in association with activation of a p53-mediated cell death program. MI-63 overcame adhesion-mediated drug resistance, showed anti-tumor activity in vivo, enhanced the activity of bortezomib and lenalidomide, and also overcame lenalidomide resistance. In mutant p53 models, inhibition of MDM2 with MI-63 also activated apoptosis, albeit at higher concentrations, and this was associated with activation of autophagy. When MI-63 was combined with the BH3 mimetic ABT-737, enhanced activity was seen in both wild-type and mutant p53 models. Finally, this regimen showed efficacy against primary plasma cells from patients with newly diagnosed and relapsed/refractory myeloma. These findings support the translation of novel MDM2 inhibitors both alone, and in combination with other novel agents, to the clinic for patients with multiple myeloma.
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Affiliation(s)
- Dongmin Gu
- Department of Lymphoma/Myeloma, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States of America
| | - Shuhong Wang
- Department of Hematology, Chinese PLA General Hospital, Beijing, China
| | - Isere Kuiatse
- Department of Lymphoma/Myeloma, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States of America
| | - Hua Wang
- Department of Lymphoma/Myeloma, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States of America
| | - Jin He
- Department of Lymphoma/Myeloma, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States of America
| | - Yun Dai
- Department of Medicine, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Richard J. Jones
- Department of Lymphoma/Myeloma, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States of America
| | - Chad C. Bjorklund
- Department of Lymphoma/Myeloma, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States of America
| | - Jing Yang
- Department of Lymphoma/Myeloma, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States of America
| | - Steven Grant
- Department of Medicine, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Robert Z. Orlowski
- Department of Lymphoma/Myeloma, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States of America
- Department of Experimental Therapeutics, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States of America
- * E-mail:
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25
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JMY is involved in anterograde vesicle trafficking from the trans-Golgi network. Eur J Cell Biol 2014; 93:194-204. [PMID: 25015719 DOI: 10.1016/j.ejcb.2014.06.001] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2013] [Revised: 05/27/2014] [Accepted: 06/02/2014] [Indexed: 01/04/2023] Open
Abstract
Junction-mediating and regulatory protein (JMY) was originally identified as a transcriptional co-factor in the p53-response to DNA damage. Aside from this nuclear function, recent years have uncovered an additional function of JMY, namely in cytoskeleton remodelling and actin assembly. The C-terminus of JMY comprises a canonical VCA-module, the sequence signature of Arp2/3 complex activators. Furthermore, tandem repeats of 3 WH2 (V, or more recently also W) domains render JMY capable of Arp2/3 independent actin assembly. The motility promoting cytoplasmic function of JMY is abrogated upon DNA-damage and nuclear translocation of JMY. To address the precise cellular function of JMY in cellular actin rearrangements, we have searched for potential new interaction partners by mass spectrometry. We identified several candidates and correlated their localization with the subcellular dynamics of JMY. JMY is localized to dynamic vesiculo-tubular structures throughout the cytoplasm, which are decorated with actin and Arp2/3 complex. Moreover, JMY partially colocalizes and interacts with VAP-A, which is involved in vesicle-based transport processes. Finally, overexpression of JMY results in Golgi dispersal by loss from the trans-site and affects VSV-G transport. These analyses, together with biochemical experiments, indicate that JMY drives vesicular trafficking in the trans-Golgi region and at ER-membrane contact sites (MCS), distinct from other Arp2/3 activators involved in vesicle transport processes such as the related WHAMM or WASH.
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26
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Guo Z, Wang X, Li H, Gao Y. Screening E3 substrates using a live phage display library. PLoS One 2013; 8:e76622. [PMID: 24124579 PMCID: PMC3790729 DOI: 10.1371/journal.pone.0076622] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2013] [Accepted: 08/26/2013] [Indexed: 11/26/2022] Open
Abstract
Ubiquitin ligases (E3s) determine specificity of ubiquitination by recognizing target substrates. However, most of their substrates are unknown. Most known substrates have been identified using distinct approaches in different laboratories. We developed a high-throughput strategy using a live phage display library as E3 substrates in in vitro screening. His-ubiquitinated phage, enriched with Ni-beads, could effectively infect E. coli for amplification. Sixteen natural potential substrates and many unnatural potential substrates of E3 MDM2 were identified through 4 independent screenings. Some substrates were identified in different independent experiments. Additionally, 10 of 12 selected candidates were ubiquitinated by MDM2 in vitro, and 3 novel substrates, DDX42, TP53RK and RPL36a were confirmed ex vivo. The whole strategy is rather simple and efficient. Non-degradation substrates can be discovered. This strategy can be extended to any E3s as long as the E3 does not ubiquitinate the empty phage.
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Affiliation(s)
- Zhengguang Guo
- Department of Physiology and Pathophysiology, National Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences/School of Basic Medicine, Peking Union Medical College, Beijing, China
- Department of Core Instrument Facility, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences/School of Basic Medicine, Peking Union Medical College, Beijing, China
| | - Xiaorong Wang
- Department of Physiology and Pathophysiology, National Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences/School of Basic Medicine, Peking Union Medical College, Beijing, China
| | - Huihua Li
- Department of Pathology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences/School of Basic Medicine, Peking Union Medical College, Beijing, China
| | - Youhe Gao
- Department of Physiology and Pathophysiology, National Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences/School of Basic Medicine, Peking Union Medical College, Beijing, China
- * E-mail:
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27
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Chai W, Lian Z, Chen C, Liu J, Shi LL, Wang Y. JARID1A, JMY, and PTGER4 polymorphisms are related to ankylosing spondylitis in Chinese Han patients: a case-control study. PLoS One 2013; 8:e74794. [PMID: 24069348 PMCID: PMC3777963 DOI: 10.1371/journal.pone.0074794] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2013] [Accepted: 08/07/2013] [Indexed: 12/20/2022] Open
Abstract
Susceptibility to ankylosing spondylitis (AS) is largely genetically determined. JARID1A, JMY and PTGER4 have recently been found to be associated with AS in patients of western European descent. We aim to examine the influence of JARID1A, JMY, and PTGER4 polymorphisms on the susceptibility to and the severity of ankylosing spondylitis in Chinese ethnic majority Han population. This work can lead the clinical doctors to intervene earlier. Blood samples were drawn from 396 AS patients and 404 unrelated healthy controls. Both the AS patients and the controls are Han Chinese. The AS patients are classified based on the severity of the disease. Thirteen tag single nucleotide polymorphisms (tagSNPs) in JARID1A, JMY and PTGER4 are selected and genotyped. Frequencies of different genotypes and alleles are analyzed among the different severity AS patients and the controls. The rs2284336 SNP in JARID1A, the rs16876619 and rs16876657 SNPs in JMY are associated with susceptibility of AS. The rs11062357 SNP in JARID1A, the rs2607142 SNP in JMY and rs10440635 in PTGER4 are related to severity of AS. Haplotype analyses indicate PTGER4 is related to susceptibility to AS; JARID1A and JMY are related to severity of AS.
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Affiliation(s)
- Wei Chai
- Department of Orthopaedics, Chinese People’s Liberation Army General Hospital, Beijing, China
| | - Zijian Lian
- Department of Orthopaedics, Tianjin Hospital, Tianjin, China
| | - Chao Chen
- Department of Orthopaedics, Tianjin Hospital, Tianjin, China
| | - Jingyi Liu
- Medical School of Nankai University, Tianjin, China
| | - Lewis L. Shi
- Department of Orthopaedics, University of Chicago Hospital, Chicago, Illinois, United States of America
| | - Yan Wang
- Department of Orthopaedics, Chinese People’s Liberation Army General Hospital, Beijing, China
- Medical School of Nankai University, Tianjin, China
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28
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Chai W, Lian Z, Chen C, Liu J, Shi LL, Wang Y. JMY polymorphism is related to severity of ankylosing spondylitis in Chinese Han patients. Genet Test Mol Biomarkers 2013; 17:637-40. [PMID: 23758122 PMCID: PMC3732413 DOI: 10.1089/gtmb.2013.0112] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Ankylosing spondylitis (AS) is a largely genetically determined autoimmune disease. JMY has recently been found to be associated with susceptibility to AS in patients of western European descent. We aimed to examine the influence of JMY polymorphisms on the severity of AS in the Chinese ethnic majority Han population. Blood samples were drawn from 396 Chinese Han AS patients whose duration of disease was about 9-12 years. Four tag single-nucleotide polymorphisms (tagSNPs) in JMY were selected and genotyped. Frequencies of different genotypes and clinical indexes about the severity of AS were analyzed. The rs2607142, rs16876619, and rs4704556 SNPs are related to BASFI. The rs2607142, rs4704556, and rs16876657 SNPs are related to BADAI. The rs4704556 and rs16876657 SNPs are related to mSASSS. JMY is related to the severity of AS in Chinese Han patients.
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Affiliation(s)
- Wei Chai
- Department of Orthopedics, Chinese People's Liberation Army General Hospital, Beijing, China
| | - Zijian Lian
- Department of Orthopedics, Tianjin Hospital, Tianjin, China
| | - Chao Chen
- Department of Orthopedics, Tianjin Hospital, Tianjin, China
| | - Jingyi Liu
- Medical School of Nankai University, Tianjin, China
| | - Lewis L. Shi
- Department of Orthopedics, University of Chicago Hospital, Chicago, Illinois
| | - Yan Wang
- Department of Orthopedics, Chinese People's Liberation Army General Hospital, Beijing, China
- Medical School of Nankai University, Tianjin, China
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29
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Nag S, Qin J, Srivenugopal KS, Wang M, Zhang R. The MDM2-p53 pathway revisited. J Biomed Res 2013; 27:254-71. [PMID: 23885265 PMCID: PMC3721034 DOI: 10.7555/jbr.27.20130030] [Citation(s) in RCA: 202] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Accepted: 04/12/2013] [Indexed: 12/15/2022] Open
Abstract
The p53 tumor suppressor is a key transcription factor regulating cellular pathways such as DNA repair, cell cycle, apoptosis, angiogenesis, and senescence. It acts as an important defense mechanism against cancer onset and progression, and is negatively regulated by interaction with the oncoprotein MDM2. In human cancers, the TP53 gene is frequently mutated or deleted, or the wild-type p53 function is inhibited by high levels of MDM2, leading to downregulation of tumor suppressive p53 pathways. Thus, the inhibition of MDM2-p53 interaction presents an appealing therapeutic strategy for the treatment of cancer. However, recent studies have revealed the MDM2-p53 interaction to be more complex involving multiple levels of regulation by numerous cellular proteins and epigenetic mechanisms, making it imperative to reexamine this intricate interplay from a holistic viewpoint. This review aims to highlight the multifaceted network of molecules regulating the MDM2-p53 axis to better understand the pathway and exploit it for anticancer therapy.
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Affiliation(s)
- Subhasree Nag
- Department of Pharmaceutical Sciences, School of Pharmacy, Texas Tech University Health Sciences Center, Amarillo, TX 79106, USA
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Qin JJ, Nag S, Voruganti S, Wang W, Zhang R. Natural product MDM2 inhibitors: anticancer activity and mechanisms of action. Curr Med Chem 2013; 19:5705-25. [PMID: 22830335 DOI: 10.2174/092986712803988910] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2012] [Revised: 06/04/2012] [Accepted: 06/04/2012] [Indexed: 12/12/2022]
Abstract
The mdm2 oncogene has recently been suggested to be a valuable target for cancer therapy and prevention. Overexpression of mdm2 is often seen in various human cancers and correlates with high-grade, late-stage, and more treatment-resistant tumors. The MDM2-p53 auto-regulatory loop has been extensively investigated and is an attractive cancer target, which indeed has been the main focus of anti-MDM2 drug discovery. Much effort has been expended in the development of small molecule MDM2 antagonists targeting the MDM2-p53 interaction, and a few of these have advanced into clinical trials. However, MDM2 exerts its oncogenic activity through both p53-dependent and -independent mechanisms. Recently, there is an increasing interest in identifying natural MDM2 inhibitors; some of them have been shown to decrease MDM2 expression and activity in vitro and in vivo. These identified natural MDM2 inhibitors include a plethora of diverse chemical frameworks, ranging from flavonoids, steroids, and sesquiterpenes to alkaloids. In addition to a brief review of synthetic MDM2 inhibitors, this review focuses on natural product MDM2 inhibitors, summarizing their biological activities in vitro and in vivo and the underlying molecular mechanisms of action, targeting MDM2 itself, regulators of MDM2, and/or the MDM2-p53 interaction. These MDM2 inhibitors can be used alone or in combination with conventional treatments, improving the prospects for cancer therapy and prevention. Their complex and unique molecular architectures may provide a stimulus for developing synthetic analogs in the future.
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Affiliation(s)
- J-J Qin
- Department of Pharmaceutical Sciences, Texas Tech University Health Sciences Center, 1300 S. Coulter Street, Amarillo, TX 79106, USA
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Li W, Katoh H, Wang L, Yu X, Du Z, Yan X, Zheng P, Liu Y. FOXP3 regulates sensitivity of cancer cells to irradiation by transcriptional repression of BRCA1. Cancer Res 2013; 73:2170-80. [PMID: 23319807 DOI: 10.1158/0008-5472.can-12-2481] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
FOXP3 is an X-linked tumor suppressor gene and a master regulator in T regulatory cell function. This gene has been found to be mutated frequently in breast and prostate cancers and to inhibit tumor cell growth, but its functional significance in DNA repair has not been studied. We found that FOXP3 silencing stimulates homologous recombination-mediated DNA repair and also repair of γ-irradiation-induced DNA damage. Expression profiling and chromatin-immunoprecipitation analyses revealed that FOXP3 regulated the BRCA1-mediated DNA repair program. Among 48 FOXP3-regulated DNA repair genes, BRCA1 and 12 others were direct targets of FOXP3 transcriptional control. Site-specific interaction of FOXP3 with the BRCA1 promoter repressed its transcription. Somatic FOXP3 mutants identified in breast cancer samples had reduced BRCA1 repressor activity, whereas FOXP3 silencing and knock-in of a prostate cancer-derived somatic FOXP3 mutant increased the radioresistance of cancer cells. Together our findings provide a missing link between FOXP3 function and DNA repair programs.
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Affiliation(s)
- Weiquan Li
- Department of Pathology, University of Michigan, Ann Arbor, MI, USA
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Abstract
Cancer cells often have high expression of Mdm2. However, in many cancers mdm2 is alternatively spliced, with more than 40 mRNA variants identified. Many of the alternative spliced mdm2 mRNAs have the potential to encode truncated Mdm2 isoforms. These putative Mdm2 isoforms can theoretically increase the diversity of the cancer proteome. The 3 best characterized are Mdm2-A, Mdm2-B, and Mdm2-C. As described in this review, the exogenous expression of these isoforms results in paradoxical phenotypes of transformation-associated growth as well as the inhibition of growth. Interestingly, these Mdm2 isoforms contribute tumor-promoting capacity in p53-null backgrounds. Herein we describe how alternative splicing of mdm2 may result in Mdm2 protein products that alter signal transduction to promote tumorigenesis. The tumor promoting capacity of Mdm2 isoforms is discussed in the context of functions that do not require the inhibition of p53. When N-terminal portions of Mdm2 are missing, the biochemical functions encoded by exon 12 are proposed to become more important. This may result in growth promoting functions when wild-type p53 is absent or compromised. The p53-independent tumor promoting activity of Mdm2 is proposed to result from C-terminal biochemical contributions of DNA binding, RNA binding, nucleolar localization, and nucleotide binding.
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Affiliation(s)
- Danielle R Okoro
- The City University of New York at Hunter College and the Graduate Center, New York, NY, USA
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Abstract
p53 is an important tumor suppressor, functioning as a transcriptional activator and repressor. Upon receiving signals from multiple stress related pathways, p53 regulates numerous activities such as cell cycle arrest, senescence, and cell death. When p53 activities are not required, the protein is held in check by interacting with 2 key homologous regulators, Mdm2 and MdmX, and a search for inhibitors of these interactions is well underway. However, it is now recognized that Mdm2 and MdmX function beyond simple inhibition of p53, and a complete understanding of Mdm2 and MdmX functions is ever more important. Indeed, increasing evidence suggests that Mdm2 and MdmX affect p53 target gene specificity and influence the activity of other transcription factors, and Mdm2 itself may even function as a transcription co-factor through post-translational modification of chromatin. Additionally, Mdm2 affects post-transcriptional activities such as mRNA stability and translation of a variety of transcripts. Thus, Mdm2 and MdmX influence the expression of many genes through a wide variety of mechanisms, which are discussed in this review.
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Affiliation(s)
- Lynn Biderman
- Department of Biological Sciences, Columbia University, New York, NY, USA
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Weston L, Coutts AS, La Thangue NB. Actin nucleators in the nucleus: an emerging theme. J Cell Sci 2012; 125:3519-27. [PMID: 22935654 DOI: 10.1242/jcs.099523] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Actin is an integral component of the cytoskeleton, forming a plethora of macromolecular structures that mediate various cellular functions. The formation of such structures relies on the ability of actin monomers to associate into polymers, and this process is regulated by actin nucleation factors. These factors use monomeric actin pools at specific cellular locations, thereby permitting rapid actin filament formation when required. It has now been established that actin is also present in the nucleus, where it is implicated in chromatin remodelling and the regulation of eukaryotic gene transcription. Notably, the presence of typical actin filaments in the nucleus has not been demonstrated directly. However, studies in recent years have provided evidence for the nuclear localisation of actin nucleation factors that promote cytoplasmic actin polymerisation. Their localisation to the nucleus suggests that these proteins mediate collaboration between the cytoskeleton and the nucleus, which might be dependent on their ability to promote actin polymerisation. The nature of this cooperation remains enigmatic and it will be important to elucidate the physiological relevance of the link between cytoskeletal actin networks and nuclear events. This Commentary explores the current evidence for the nuclear roles of actin nucleation factors. Furthermore, the implication of actin-associated proteins in relaying exogenous signals to the nucleus, particularly in response to cellular stress, will be considered.
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Affiliation(s)
- Louise Weston
- Laboratory of Cancer Biology, Department of Oncology, University of Oxford, Old Road Campus Research Building, Oxford OX3 7DQ, UK.
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Andrin C, McDonald D, Attwood KM, Rodrigue A, Ghosh S, Mirzayans R, Masson JY, Dellaire G, Hendzel MJ. A requirement for polymerized actin in DNA double-strand break repair. Nucleus 2012; 3:384-95. [PMID: 22688650 DOI: 10.4161/nucl.21055] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Nuclear actin is involved in several nuclear processes from chromatin remodeling to transcription. Here we examined the requirement for actin polymerization in DNA double-strand break repair. Double-strand breaks are considered the most dangerous type of DNA lesion. Double-strand break repair consists of a complex set of events that are tightly regulated. Failure at any step can have catastrophic consequences such as genomic instability, oncogenesis or cell death. Many proteins involved in this repair process have been identified and their roles characterized. We discovered that some DNA double-strand break repair factors are capable of associating with polymeric actin in vitro and specifically, that purified Ku70/80 interacts with polymerized actin under these conditions. We find that the disruption of polymeric actin inhibits DNA double strand break repair both in vitro and in vivo. Introduction of nuclear targeted mutant actin that cannot polymerize, or the depolymerization of endogenous actin filaments by the addition of cytochalasin D, alters the retention of Ku80 at sites of DNA damage in live cells. Our results suggest that polymeric actin is required for proper DNA double-strand break repair and may function through the stabilization of the Ku heterodimer at the DNA damage site.
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Affiliation(s)
- Christi Andrin
- Department of Oncology, University of Alberta, Edmonton, AB Canada
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Rodriguez-Mesa E, Abreu-Blanco MT, Rosales-Nieves AE, Parkhurst SM. Developmental expression of Drosophila Wiskott-Aldrich Syndrome family proteins. Dev Dyn 2012; 241:608-26. [PMID: 22275148 DOI: 10.1002/dvdy.23742] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/07/2012] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Wiskott-Aldrich Syndrome (WASP) family proteins participate in many cellular processes involving rearrangements of the actin cytoskeleton. To the date, four WASP subfamily members have been described in Drosophila: Wash, WASp, SCAR, and Whamy. Wash, WASp, and SCAR are essential during early Drosophila development where they function in orchestrating cytoplasmic events including membrane-cytoskeleton interactions. A mutant for Whamy has not yet been reported. RESULTS We generated monoclonal antibodies that are specific to Drosophila Wash, WASp, SCAR, and Whamy, and use these to describe their spatial and temporal localization patterns. Consistent with the importance of WASP family proteins in flies, we find that Wash, WASp, SCAR, and Whamy are dynamically expressed throughout oogenesis and embryogenesis. For example, we find that Wash accumulates at the oocyte cortex. WASp is highly expressed in the PNS, while SCAR is the most abundantly expressed in the CNS. Whamy exhibits an asymmetric subcellular localization that overlaps with mitochondria and is highly expressed in muscle. CONCLUSIONS All four WASP family members show specific expression patterns, some of which reflect their previously known roles and others revealing new potential functions. The monoclonal antibodies developed offer valuable new tools to investigate how WASP family proteins regulate actin cytoskeleton dynamics.
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Affiliation(s)
- Evelyn Rodriguez-Mesa
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109-1024, USA
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Zuchero JB, Belin B, Mullins RD. Actin binding to WH2 domains regulates nuclear import of the multifunctional actin regulator JMY. Mol Biol Cell 2012; 23:853-63. [PMID: 22262458 PMCID: PMC3290644 DOI: 10.1091/mbc.e11-12-0992] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
In the cytoplasm, JMY regulates actin assembly, whereas in the nucleus, it promotes DNA damage–induced apoptosis. This study demonstrates that nuclear translocation of JMY is controlled by the concentration of monomeric actin in the cytoplasm. Junction-mediating and regulatory protein (JMY) is a regulator of both transcription and actin filament assembly. In response to DNA damage, JMY accumulates in the nucleus and promotes p53-dependent apoptosis. JMY's actin-regulatory activity relies on a cluster of three actin-binding Wiskott–Aldrich syndrome protein homology 2 (WH2) domains that nucleate filaments directly and also promote nucleation activity of the Arp2/3 complex. In addition to these activities, we find that the WH2 cluster overlaps an atypical, bipartite nuclear localization sequence (NLS) and controls JMY's subcellular localization. Actin monomers bound to the WH2 domains block binding of importins to the NLS and prevent nuclear import of JMY. Mutations that impair actin binding, or cellular perturbations that induce actin filament assembly and decrease the concentration of monomeric actin in the cytoplasm, cause JMY to accumulate in the nucleus. DNA damage induces both cytoplasmic actin polymerization and nuclear import of JMY, and we find that damage-induced nuclear localization of JMY requires both the WH2/NLS region and importin β. On the basis of our results, we propose that actin assembly regulates nuclear import of JMY in response to DNA damage.
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Affiliation(s)
- J Bradley Zuchero
- Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA
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Quadrato G, Di Giovanni S. Gatekeeper between quiescence and differentiation: p53 in axonal outgrowth and neurogenesis. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2012. [PMID: 23206596 DOI: 10.1016/b978-0-12-398309-1.00005-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The transcription factor and tumor suppressor gene p53 regulates a wide range of cellular processes including DNA damage/repair, cell cycle progression, apoptosis, and cell metabolism. In the past several years, a specific novel role for p53 in neuronal biology has emerged. p53 orchestrates the polarity of self-renewing divisions in neural stem cells both during embryonic development and in adulthood and coordinates the timing for cell fate specification. In postmitotic neurons, p53 regulates neurite outgrowth and postinjury axonal regeneration via neurotrophin-dependent and -independent signaling by both transcriptional and posttranslational control of growth cone remodeling. This review provides an insight into the molecular mechanisms upstream and downstream p53 both during neural development and following axonal injury. Their understanding may provide therapeutic targets to enhance neuroregeneration following nervous system injury.
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Affiliation(s)
- Giorgia Quadrato
- Laboratory for NeuroRegeneration and Repair, Center for Neurology, Hertie Institute for Clinical Brain Research, University of Tuebingen, Tuebingen, Germany
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Firat-Karalar EN, Hsiue PP, Welch MD. The actin nucleation factor JMY is a negative regulator of neuritogenesis. Mol Biol Cell 2011; 22:4563-74. [PMID: 21965285 PMCID: PMC3226475 DOI: 10.1091/mbc.e11-06-0585] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Junction-mediating and regulatory protein (JMY) is a p53 cofactor that was recently shown to nucleate actin assembly by a hybrid mechanism involving tandem actin monomer binding and Arp2/3 complex activation. However, the regulation and function of JMY remain largely uncharacterized. We examined the activity of JMY in vitro and in cells, its subcellular distribution, and its function in fibroblast and neuronal cell lines. We demonstrated that recombinant full-length JMY and its isolated WASP homology 2 domain, connector, and acidic region (WWWCA) have potent actin-nucleating and Arp2/3-activating abilities in vitro. In contrast, the activity of full-length JMY, but not the isolated WWWCA domain, is suppressed in cells. The WWWCA domain is sufficient to promote actin-based bead motility in cytoplasmic extracts, and this activity depends on its ability to activate the Arp2/3 complex. JMY is expressed at high levels in brain tissue, and in various cell lines JMY is predominantly cytoplasmic, with a minor fraction in the nucleus. Of interest, silencing JMY expression in neuronal cells results in a significant enhancement of the ability of these cells to form neurites, suggesting that JMY functions to suppress neurite formation. This function of JMY requires its actin-nucleating activity. These findings highlight a previously unrecognized function for JMY as a modulator of neuritogenesis.
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Affiliation(s)
- Elif Nur Firat-Karalar
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
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40
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Coutts AS, Pires IM, Weston L, Buffa FM, Milani M, Li JL, Harris AL, Hammond EM, La Thangue NB. Hypoxia-driven cell motility reflects the interplay between JMY and HIF-1α. Oncogene 2011; 30:4835-42. [DOI: 10.1038/onc.2011.188] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Abstract
Mutations in the TP53 gene are a feature of 50% of all reported cancer cases. In the other 50% of cases, the TP53 gene itself is not mutated but the p53 pathway is often partially inactivated. Cancer therapies that target specific mutant genes are proving to be highly active and trials assessing agents that exploit the p53 system are ongoing. Many trials are aimed at stratifying patients on the basis of TP53 status. In another approach, TP53 is delivered as a gene therapy; this is the only currently approved p53-based treatment. The p53 protein is overexpressed in many cancers and p53-based vaccines are undergoing trials. Processed cell-surface p53 is being exploited as a target for protein-drug conjugates, and small-molecule drugs that inhibit the activity of MDM2, the E3 ligase that regulates p53 levels, have been developed by several companies. The first MDM2 inhibitors are being trialed in both hematologic and solid malignancies. Finally, the first agent found to restore the active function of mutant TP53 has just entered the clinic. Here we discuss the basis of these trials and the future of p53-based therapy.
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WASH, WHAMM and JMY: regulation of Arp2/3 complex and beyond. Trends Cell Biol 2010; 20:650-61. [PMID: 20888769 DOI: 10.1016/j.tcb.2010.08.014] [Citation(s) in RCA: 140] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2010] [Revised: 08/16/2010] [Accepted: 08/30/2010] [Indexed: 02/07/2023]
Abstract
Arp2/3 complex mediates the nucleation of actin filaments in multiple subcellular processes, and is activated by nucleation-promoting factors (NPFs) from the Wiskott-Aldrich Syndrome family. In exciting new developments, this family has grown by three members: WASH, WHAMM and JMY, which extend the repertoire of dynamic membrane structures that are remodeled following Arp2/3 activation in vivo. These novel NPFs share an actin- and Arp2/3-interacting WCA module, and combine Arp2/3 activation with additional biochemical functions, including capping protein inhibition, microtubule engagement or Arp2/3-independent actin nucleation, none of which had been previously associated with canonical WCA-harboring proteins. Uncovering the physiological relevance of these unique activities will require concerted efforts from multiple disciplines, and is sure to impact our understanding of how the cytoskeleton controls so many dynamic subcellular events.
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Wang Y. JimMY on the stage: Linking DNA damage with cell adhesion and motility. Cell Adh Migr 2010; 4:166-8. [PMID: 20574148 DOI: 10.4161/cam.4.2.11368] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Cellular DNA undergoes constant assault from a wide range of genotoxic stress. In order to maintain genome integrity, cells develop a repertoire of sophisticated systems to detect DNA damage and mediate cellular responses to DNA damage. Defects in the DNA damage response have been implicated in a variety of disorders including aging and cancer. Tumor suppressor p53 is a key intermediate in DNA damage response by inducing cell cycle arrest to allow repair or promoting apoptosis to eliminate irreparably damaged cells. A recent study described a novel layer of p53-mediated cellular response to DNA damage, i.e., modulation of cell adhesion and motility. JMY, a p53 co-factor, was demonstrated to be a multifunctional protein that coordinates cell adhesion and motility with nuclear p53 response. These results suggest that abnormal JMY activity and/or localization could contribute to tumor invasion and reveal JMY as a potential therapeutic target.
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Affiliation(s)
- Yingqun Wang
- Department of Cancer Biology, Abramson Family Cancer Research Institute, University of Pennsylvania, Philadelphia, PA, USA.
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Abstract
The really interesting genes (RING)-finger-containing oncoprotein, Mdm2, is a promising drug target for cancer therapy. A key Mdm2 function is to promote ubiquitylation and proteasomal-dependent degradation of the tumor suppressor protein p53. Recent reports provide novel important insights into Mdm2-mediated regulation of p53 and how the physical and functional interactions between these two proteins are regulated. Moreover, a p53-independent role of Mdm2 has recently been confirmed by genetic data. These advances and their potential implications for the development of new cancer therapeutic strategies form the focus of this review.
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Affiliation(s)
- J-C Marine
- Laboratory For Molecular Cancer Biology, VIB-UGent, Ghent B-9052, Belgium.
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46
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Rayburn ER, Ezell SJ, Zhang R. Recent advances in validating MDM2 as a cancer target. Anticancer Agents Med Chem 2010; 9:882-903. [PMID: 19538162 DOI: 10.2174/187152009789124628] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2008] [Accepted: 05/14/2008] [Indexed: 12/26/2022]
Abstract
The MDM2 oncogene is overexpressed in various human cancers. Its expression correlates with the phenotypes of high-grade, late-stage, and more resistant tumors. The auto-regulatory loop between MDM2 and the tumor suppressor p53 has long been considered the epitome of a rational target for cancer therapy. As such, many novel agents have been generated to interfere with the interaction of the two proteins, which results in the activation of p53. Among these agents are several small molecule inhibitors synthesized based upon the crystal structures of the MDM2-p53 complex. With use of high-throughput screening, several specific and effective agents for inhibition of the protein-protein interaction were discovered. Recent investigations, however, have demonstrated that many proteins regulate the MDM2-p53 interaction, and that MDM2 may have p53-independent oncogenic functions. In order for novel MDM2 inhibitors to be translated to the clinic, it is necessary to obtain a better understanding of the regulation of MDM2 and of the MDM2-p53 interaction. In particular, the implications of various interactions between certain regulator(s) and MDM2/p53 under different circumstances need to be elucidated to determine which pathway(s) represent the best targets for therapy. Targeting both MDM2 itself and regulators of MDM2 and the MDM2-p53 interaction, or use of MDM2 inhibitors in combination with conventional treatments, may improve prospects for tumor eradication.
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Affiliation(s)
- Elizabeth R Rayburn
- Department of Pharmacology and Toxicology, Division of Clinical Pharmacology, University of Alabama at Birmingham, Birmingham, AL 35294-0019, USA
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A transcription co-factor integrates cell adhesion and motility with the p53 response. Proc Natl Acad Sci U S A 2009; 106:19872-7. [PMID: 19897726 DOI: 10.1073/pnas.0906785106] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Despite its obvious importance in tumorigenesis, little information is available on the mechanisms that integrate cell motility and adhesion with nuclear events. JMY is a transcription co-factor that regulates the p53 response. In addition, JMY contains a series of WH2 domains that facilitate in vitro actin nucleation. We show here that the ability of JMY to influence cell motility is dependent, in part, on its control of cadherin expression as well as the WH2 domains. In DNA damage conditions JMY undergoes nuclear accumulation, which drives the p53 transcription response but reduces its influence on cell motility. Consequently, the role of JMY in actin nucleation is less in damaged cells, although the WH2 domains remain functional in the nucleus where they impact on p53 activity. Together, these findings demonstrate a pathway that links the cytoskeleton with the p53 response, and further suggest that the ability of JMY to regulate actin and cadherin is instrumental in coordinating cell motility with the p53 response.
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48
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From structure to dynamics: Frequency tuning in the p53–Mdm2 network. J Theor Biol 2009; 258:561-77. [DOI: 10.1016/j.jtbi.2009.02.005] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2008] [Revised: 01/19/2009] [Accepted: 02/11/2009] [Indexed: 11/19/2022]
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Abstract
The assembly of actin networks is dependent on nucleation-promoting factors. A new study identifies JMY as a protein containing two separate nucleation-promoting activities that shuttles between the nucleus and the cytoplasm and promotes cell migration. These observations indicate that JMY is an important factor controlling actin dynamics in motile cells.
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50
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p53-cofactor JMY is a multifunctional actin nucleation factor. Nat Cell Biol 2009; 11:451-9. [PMID: 19287377 PMCID: PMC2763628 DOI: 10.1038/ncb1852] [Citation(s) in RCA: 191] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2008] [Accepted: 01/29/2009] [Indexed: 12/25/2022]
Abstract
Many cellular structures are assembled from networks of actin filaments, and the architecture of these networks depends on the mechanism by which the filaments are formed. Several classes of proteins are known to assemble new filaments, including the Arp2/3 complex, which creates branched filament networks, and Spire, which creates unbranched filaments. We find that JMY, a vertebrate protein first identified as a transcriptional co-activator of p53, combines these two nucleating activities by both activating Arp2/3 and assembling filaments directly using a Spire-like mechanism. Increased levels of JMY expression enhance motility, whereas loss of JMY slows cell migration. When slowly migrating HL-60 cells are differentiated into highly motile neutrophil-like cells, JMY moves from the nucleus to the cytoplasm and is concentrated at the leading edge. Thus, JMY represents a new class of multifunctional actin assembly factor whose activity is regulated, at least in part, by sequestration in the nucleus.
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