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Ulferts S, Lopes M, Miyamoto K, Grosse R. Nuclear actin dynamics and functions at a glance. J Cell Sci 2024; 137:jcs261630. [PMID: 38563209 DOI: 10.1242/jcs.261630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/04/2024] Open
Abstract
Actin is well known for its cytoskeletal functions, where it helps to control and maintain cell shape and architecture, as well as regulating cell migration and intracellular cargo transport, among others. However, actin is also prevalent in the nucleus, where genome-regulating roles have been described, including it being part of chromatin-remodeling complexes. More recently, with the help of advances in microscopy techniques and specialized imaging probes, direct visualization of nuclear actin filament dynamics has helped elucidate new roles for nuclear actin, such as in cell cycle regulation, DNA replication and repair, chromatin organization and transcriptional condensate formation. In this Cell Science at a Glance article, we summarize the known signaling events driving the dynamic assembly of actin into filaments of various structures within the nuclear compartment for essential genome functions. Additionally, we highlight the physiological role of nuclear F-actin in meiosis and early embryonic development.
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Affiliation(s)
- Svenja Ulferts
- Institute for Clinical and Experimental Pharmacology and Toxicology I, Medical Faculty, University of Freiburg, 79104 Freiburg, Germany
| | - Massimo Lopes
- Institute of Molecular Cancer Research, University of Zurich, 8057 Zurich, Switzerland
| | - Kei Miyamoto
- Faculty of Biology-Oriented Science and Technology, Kindai University, Wakayama 649-6493, Japan
| | - Robert Grosse
- Institute for Clinical and Experimental Pharmacology and Toxicology I, Medical Faculty, University of Freiburg, 79104 Freiburg, Germany
- Centre for Integrative Biological Signalling Studies (CIBSS), 79104 Freiburg, Germany
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2
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Nasheuer HP, Meaney AM, Hulshoff T, Thiele I, Onwubiko NO. Replication Protein A, the Main Eukaryotic Single-Stranded DNA Binding Protein, a Focal Point in Cellular DNA Metabolism. Int J Mol Sci 2024; 25:588. [PMID: 38203759 PMCID: PMC10779431 DOI: 10.3390/ijms25010588] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 12/28/2023] [Accepted: 12/29/2023] [Indexed: 01/12/2024] Open
Abstract
Replication protein A (RPA) is a heterotrimeric protein complex and the main single-stranded DNA (ssDNA)-binding protein in eukaryotes. RPA has key functions in most of the DNA-associated metabolic pathways and DNA damage signalling. Its high affinity for ssDNA helps to stabilise ssDNA structures and protect the DNA sequence from nuclease attacks. RPA consists of multiple DNA-binding domains which are oligonucleotide/oligosaccharide-binding (OB)-folds that are responsible for DNA binding and interactions with proteins. These RPA-ssDNA and RPA-protein interactions are crucial for DNA replication, DNA repair, DNA damage signalling, and the conservation of the genetic information of cells. Proteins such as ATR use RPA to locate to regions of DNA damage for DNA damage signalling. The recruitment of nucleases and DNA exchange factors to sites of double-strand breaks are also an important RPA function to ensure effective DNA recombination to correct these DNA lesions. Due to its high affinity to ssDNA, RPA's removal from ssDNA is of central importance to allow these metabolic pathways to proceed, and processes to exchange RPA against downstream factors are established in all eukaryotes. These faceted and multi-layered functions of RPA as well as its role in a variety of human diseases will be discussed.
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Affiliation(s)
- Heinz Peter Nasheuer
- Centre for Chromosome Biology, School of Biological and Chemical Sciences, Biochemistry, University of Galway, H91 TK33 Galway, Ireland
| | - Anna Marie Meaney
- Centre for Chromosome Biology, School of Biological and Chemical Sciences, Biochemistry, University of Galway, H91 TK33 Galway, Ireland
| | - Timothy Hulshoff
- Molecular Systems Physiology Group, School of Biological and Chemical Sciences, University of Galway, H91 TK33 Galway, Ireland
| | - Ines Thiele
- Molecular Systems Physiology Group, School of Biological and Chemical Sciences, University of Galway, H91 TK33 Galway, Ireland
| | - Nichodemus O. Onwubiko
- Centre for Chromosome Biology, School of Biological and Chemical Sciences, Biochemistry, University of Galway, H91 TK33 Galway, Ireland
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3
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Spegg V, Altmeyer M. Genome maintenance meets mechanobiology. Chromosoma 2024; 133:15-36. [PMID: 37581649 PMCID: PMC10904543 DOI: 10.1007/s00412-023-00807-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 06/20/2023] [Accepted: 07/26/2023] [Indexed: 08/16/2023]
Abstract
Genome stability is key for healthy cells in healthy organisms, and deregulated maintenance of genome integrity is a hallmark of aging and of age-associated diseases including cancer and neurodegeneration. To maintain a stable genome, genome surveillance and repair pathways are closely intertwined with cell cycle regulation and with DNA transactions that occur during transcription and DNA replication. Coordination of these processes across different time and length scales involves dynamic changes of chromatin topology, clustering of fragile genomic regions and repair factors into nuclear repair centers, mobilization of the nuclear cytoskeleton, and activation of cell cycle checkpoints. Here, we provide a general overview of cell cycle regulation and of the processes involved in genome duplication in human cells, followed by an introduction to replication stress and to the cellular responses elicited by perturbed DNA synthesis. We discuss fragile genomic regions that experience high levels of replication stress, with a particular focus on telomere fragility caused by replication stress at the ends of linear chromosomes. Using alternative lengthening of telomeres (ALT) in cancer cells and ALT-associated PML bodies (APBs) as examples of replication stress-associated clustered DNA damage, we discuss compartmentalization of DNA repair reactions and the role of protein properties implicated in phase separation. Finally, we highlight emerging connections between DNA repair and mechanobiology and discuss how biomolecular condensates, components of the nuclear cytoskeleton, and interfaces between membrane-bound organelles and membraneless macromolecular condensates may cooperate to coordinate genome maintenance in space and time.
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Affiliation(s)
- Vincent Spegg
- Department of Molecular Mechanisms of Disease, University of Zurich, Zurich, Switzerland
| | - Matthias Altmeyer
- Department of Molecular Mechanisms of Disease, University of Zurich, Zurich, Switzerland.
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4
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González-Acosta D, Lopes M. DNA replication and replication stress response in the context of nuclear architecture. Chromosoma 2024; 133:57-75. [PMID: 38055079 PMCID: PMC10904558 DOI: 10.1007/s00412-023-00813-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Revised: 10/23/2023] [Accepted: 10/24/2023] [Indexed: 12/07/2023]
Abstract
The DNA replication process needs to be coordinated with other DNA metabolism transactions and must eventually extend to the full genome, regardless of chromatin status, gene expression, secondary structures and DNA lesions. Completeness and accuracy of DNA replication are crucial to maintain genome integrity, limiting transformation in normal cells and offering targeting opportunities for proliferating cancer cells. DNA replication is thus tightly coordinated with chromatin dynamics and 3D genome architecture, and we are only beginning to understand the underlying molecular mechanisms. While much has recently been discovered on how DNA replication initiation is organised and modulated in different genomic regions and nuclear territories-the so-called "DNA replication program"-we know much less on how the elongation of ongoing replication forks and particularly the response to replication obstacles is affected by the local nuclear organisation. Also, it is still elusive how specific components of nuclear architecture participate in the replication stress response. Here, we review known mechanisms and factors orchestrating replication initiation, and replication fork progression upon stress, focusing on recent evidence linking genome organisation and nuclear architecture with the cellular responses to replication interference, and highlighting open questions and future challenges to explore this exciting new avenue of research.
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Affiliation(s)
| | - Massimo Lopes
- Institute of Molecular Cancer Research, University of Zurich, Zurich, Switzerland.
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5
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Palumbieri MD, Merigliano C, González-Acosta D, Kuster D, Krietsch J, Stoy H, von Känel T, Ulferts S, Welter B, Frey J, Doerdelmann C, Sanchi A, Grosse R, Chiolo I, Lopes M. Nuclear actin polymerization rapidly mediates replication fork remodeling upon stress by limiting PrimPol activity. Nat Commun 2023; 14:7819. [PMID: 38016948 PMCID: PMC10684888 DOI: 10.1038/s41467-023-43183-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Accepted: 11/02/2023] [Indexed: 11/30/2023] Open
Abstract
Cells rapidly respond to replication stress actively slowing fork progression and inducing fork reversal. How replication fork plasticity is achieved in the context of nuclear organization is currently unknown. Using nuclear actin probes in living and fixed cells, we visualized nuclear actin filaments in unperturbed S phase and observed their rapid extension in number and length upon genotoxic treatments, frequently taking contact with replication factories. Chemically or genetically impairing nuclear actin polymerization shortly before these treatments prevents active fork slowing and abolishes fork reversal. Defective fork remodeling is linked to deregulated chromatin loading of PrimPol, which promotes unrestrained and discontinuous DNA synthesis and limits the recruitment of RAD51 and SMARCAL1 to nascent DNA. Moreover, defective nuclear actin polymerization upon mild replication interference induces chromosomal instability in a PRIMPOL-dependent manner. Hence, by limiting PrimPol activity, nuclear F-actin orchestrates replication fork plasticity and is a key molecular determinant in the rapid cellular response to genotoxic treatments.
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Affiliation(s)
| | - Chiara Merigliano
- Molecular and Computational Biology Department, University of Southern California, Los Angeles, CA, USA
| | | | - Danina Kuster
- Institute of Molecular Cancer Research, University of Zurich, Zurich, Switzerland
| | - Jana Krietsch
- Institute of Molecular Cancer Research, University of Zurich, Zurich, Switzerland
| | - Henriette Stoy
- Institute of Molecular Cancer Research, University of Zurich, Zurich, Switzerland
- Department of Cellular and Molecular Medicine, Copenhagen University, Copenhagen, Denmark
| | - Thomas von Känel
- Institute of Molecular Cancer Research, University of Zurich, Zurich, Switzerland
| | - Svenja Ulferts
- Institute of Experimental and Clinical Pharmacology and Toxicology, Medical Faculty, University of Freiburg, Freiburg im Breisgau, Germany
| | - Bettina Welter
- Institute of Molecular Cancer Research, University of Zurich, Zurich, Switzerland
| | - Joël Frey
- Institute of Molecular Cancer Research, University of Zurich, Zurich, Switzerland
| | - Cyril Doerdelmann
- Institute of Molecular Cancer Research, University of Zurich, Zurich, Switzerland
| | - Andrea Sanchi
- Institute of Molecular Cancer Research, University of Zurich, Zurich, Switzerland
| | - Robert Grosse
- Institute of Experimental and Clinical Pharmacology and Toxicology, Medical Faculty, University of Freiburg, Freiburg im Breisgau, Germany
- CIBSS - Centre for Integrative Biological Signaling Studies, University of Freiburg, Freiburg im Breisgau, Germany
| | - Irene Chiolo
- Molecular and Computational Biology Department, University of Southern California, Los Angeles, CA, USA.
| | - Massimo Lopes
- Institute of Molecular Cancer Research, University of Zurich, Zurich, Switzerland.
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Wollscheid HP, Ulrich HD. Chromatin meets the cytoskeleton: the importance of nuclear actin dynamics and associated motors for genome stability. DNA Repair (Amst) 2023; 131:103571. [PMID: 37738698 DOI: 10.1016/j.dnarep.2023.103571] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Revised: 09/11/2023] [Accepted: 09/13/2023] [Indexed: 09/24/2023]
Abstract
The actin cytoskeleton is of fundamental importance for numerous cellular processes, including intracellular transport, cell plasticity, and cell migration. However, functions of filamentous actin (F-actin) in the nucleus remain understudied due to the comparatively low abundance of nuclear actin and the resulting experimental limitations to its visualization. Owing to recent technological advances such as super-resolution microscopy and the development of nuclear-specific actin probes, essential roles of the actin cytoskeleton in the context of genome maintenance are now emerging. In addition to the contributions of monomeric actin as a component of multiple important nuclear protein complexes, nuclear actin has been found to undergo polymerization in response to DNA damage and DNA replication stress. Consequently, nuclear F-actin plays important roles in the regulation of intra-nuclear mobility of repair and replication foci as well as the maintenance of nuclear shape, two important aspects of efficient stress tolerance. Beyond actin itself, there is accumulating evidence for the participation of multiple actin-binding proteins (ABPs) in the surveillance of genome integrity, including nucleation factors and motor proteins of the myosin family. Here we summarize recent findings highlighting the importance of actin cytoskeletal factors within the nucleus in key genome maintenance pathways.
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Affiliation(s)
- Hans-Peter Wollscheid
- Institute of Molecular Biology gGmbH (IMB), Ackermannweg 4, Mainz D - 55128, Germany.
| | - Helle D Ulrich
- Institute of Molecular Biology gGmbH (IMB), Ackermannweg 4, Mainz D - 55128, Germany.
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Feng Y, Jiang Y, Liu J, Liu J, Shi M, Chen J, Zhang J, Tian Y, Yang X, Liu H. Targeting RPA promotes autophagic flux and the antitumor response to radiation in nasopharyngeal carcinoma. J Transl Med 2023; 21:738. [PMID: 37858134 PMCID: PMC10585929 DOI: 10.1186/s12967-023-04574-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Accepted: 09/28/2023] [Indexed: 10/21/2023] Open
Abstract
BACKGROUND Autophagy is involved in nasopharyngeal carcinoma (NPC) radioresistance. Replication protein A 1 (RPA1) and RPA3, substrates of the RPA complex, are potential therapeutic targets for reversing NPC radioresistance. Nevertheless, the role of RPA in autophagy is not adequately understood. This investigation was performed to reveal the cytotoxic mechanism of a pharmacologic RPA inhibitor (RPAi) in NPC cells and the underlying mechanism by which RPAi-mediated autophagy regulates NPC radiosensitivity. METHODS AND RESULTS We characterized a potent RPAi (HAMNO) that was substantially correlated with radiosensitivity enhancement and proliferative inhibition of in vivo and in NPC cell lines in vitro. We show that the RPAi induced autophagy at multiple levels by inducing autophagic flux, AMPK/mTOR pathway activation, and autophagy-related gene transcription by decreasing glycolytic function. We hypothesized that RPA inhibition impaired glycolysis and increased NPC dependence on autophagy. We further demonstrated that combining autophagy inhibition with chloroquine (CQ) treatment or genetic inhibition of the autophagy regulator ATG5 and RPAi treatment was more effective than either approach alone in enhancing the antitumor response of NPC to radiation. CONCLUSIONS Our study suggests that HAMNO is a potent RPAi that enhances radiosensitivity and induces autophagy in NPC cell lines by decreasing glycolytic function and activating autophagy-related genes. We suggest a novel treatment strategy in which pharmacological inhibitors that simultaneously disrupt RPA and autophagic processes improve NPC responsiveness to radiation.
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Affiliation(s)
- Yanchun Feng
- Department of Clinical Laboratory, The Sixth Affiliated Hospital, Sun Yat-Sen University, Guangzhou, 510655, China
- Guangdong Institute of Gastroenterology, Guangzhou, 510655, China
- Department of General Surgery, The Sixth Affiliated Hospital, Sun Yat-Sen University, Guangzhou, 510655, China
- Guangdong Provincial Key Laboratory of Colorectal and Pelvic Floor Diseases, The Sixth Affiliated Hospital, Sun Yat-Sen University, Guangzhou, 510655, China
- Biomedical Innovation Center, The Sixth Affiliated Hospital, Sun Yat-Sen University, Guangzhou, 510655, China
| | - Yingming Jiang
- Guangdong Institute of Gastroenterology, Guangzhou, 510655, China
- Department of General Surgery, The Sixth Affiliated Hospital, Sun Yat-Sen University, Guangzhou, 510655, China
- Guangdong Provincial Key Laboratory of Colorectal and Pelvic Floor Diseases, The Sixth Affiliated Hospital, Sun Yat-Sen University, Guangzhou, 510655, China
- Biomedical Innovation Center, The Sixth Affiliated Hospital, Sun Yat-Sen University, Guangzhou, 510655, China
- Department of General Surgery (Department of Gastric Surgery Section 2, ), The Sixth Affiliated Hospital, Sun Yat-Sen University, Guangzhou, 510655, China
| | - Jun Liu
- Department of Clinical Laboratory, The Sixth Affiliated Hospital, Sun Yat-Sen University, Guangzhou, 510655, China
- Guangdong Institute of Gastroenterology, Guangzhou, 510655, China
- Department of General Surgery, The Sixth Affiliated Hospital, Sun Yat-Sen University, Guangzhou, 510655, China
- Guangdong Provincial Key Laboratory of Colorectal and Pelvic Floor Diseases, The Sixth Affiliated Hospital, Sun Yat-Sen University, Guangzhou, 510655, China
- Biomedical Innovation Center, The Sixth Affiliated Hospital, Sun Yat-Sen University, Guangzhou, 510655, China
| | - Jiaqi Liu
- Department of Clinical Laboratory, The Sixth Affiliated Hospital, Sun Yat-Sen University, Guangzhou, 510655, China
- Guangdong Institute of Gastroenterology, Guangzhou, 510655, China
- Department of General Surgery, The Sixth Affiliated Hospital, Sun Yat-Sen University, Guangzhou, 510655, China
- Guangdong Provincial Key Laboratory of Colorectal and Pelvic Floor Diseases, The Sixth Affiliated Hospital, Sun Yat-Sen University, Guangzhou, 510655, China
- Biomedical Innovation Center, The Sixth Affiliated Hospital, Sun Yat-Sen University, Guangzhou, 510655, China
| | - Mengchen Shi
- Department of Clinical Laboratory, The Sixth Affiliated Hospital, Sun Yat-Sen University, Guangzhou, 510655, China
- Guangdong Institute of Gastroenterology, Guangzhou, 510655, China
- Department of General Surgery, The Sixth Affiliated Hospital, Sun Yat-Sen University, Guangzhou, 510655, China
- Guangdong Provincial Key Laboratory of Colorectal and Pelvic Floor Diseases, The Sixth Affiliated Hospital, Sun Yat-Sen University, Guangzhou, 510655, China
- Biomedical Innovation Center, The Sixth Affiliated Hospital, Sun Yat-Sen University, Guangzhou, 510655, China
| | - Junxiong Chen
- Department of Clinical Laboratory, The Sixth Affiliated Hospital, Sun Yat-Sen University, Guangzhou, 510655, China
- Guangdong Institute of Gastroenterology, Guangzhou, 510655, China
- Department of General Surgery, The Sixth Affiliated Hospital, Sun Yat-Sen University, Guangzhou, 510655, China
- Guangdong Provincial Key Laboratory of Colorectal and Pelvic Floor Diseases, The Sixth Affiliated Hospital, Sun Yat-Sen University, Guangzhou, 510655, China
- Biomedical Innovation Center, The Sixth Affiliated Hospital, Sun Yat-Sen University, Guangzhou, 510655, China
| | - Jingdan Zhang
- Department of Clinical Laboratory, The Sixth Affiliated Hospital, Sun Yat-Sen University, Guangzhou, 510655, China
- Guangdong Institute of Gastroenterology, Guangzhou, 510655, China
- Department of General Surgery, The Sixth Affiliated Hospital, Sun Yat-Sen University, Guangzhou, 510655, China
- Guangdong Provincial Key Laboratory of Colorectal and Pelvic Floor Diseases, The Sixth Affiliated Hospital, Sun Yat-Sen University, Guangzhou, 510655, China
- Biomedical Innovation Center, The Sixth Affiliated Hospital, Sun Yat-Sen University, Guangzhou, 510655, China
| | - Yu Tian
- Department of Clinical Laboratory, The Sixth Affiliated Hospital, Sun Yat-Sen University, Guangzhou, 510655, China
- Guangdong Institute of Gastroenterology, Guangzhou, 510655, China
- Department of General Surgery, The Sixth Affiliated Hospital, Sun Yat-Sen University, Guangzhou, 510655, China
- Guangdong Provincial Key Laboratory of Colorectal and Pelvic Floor Diseases, The Sixth Affiliated Hospital, Sun Yat-Sen University, Guangzhou, 510655, China
- Biomedical Innovation Center, The Sixth Affiliated Hospital, Sun Yat-Sen University, Guangzhou, 510655, China
| | - Xiangling Yang
- Department of Clinical Laboratory, The Sixth Affiliated Hospital, Sun Yat-Sen University, Guangzhou, 510655, China.
- Guangdong Institute of Gastroenterology, Guangzhou, 510655, China.
- Department of General Surgery, The Sixth Affiliated Hospital, Sun Yat-Sen University, Guangzhou, 510655, China.
- Guangdong Provincial Key Laboratory of Colorectal and Pelvic Floor Diseases, The Sixth Affiliated Hospital, Sun Yat-Sen University, Guangzhou, 510655, China.
- Biomedical Innovation Center, The Sixth Affiliated Hospital, Sun Yat-Sen University, Guangzhou, 510655, China.
| | - Huanliang Liu
- Department of Clinical Laboratory, The Sixth Affiliated Hospital, Sun Yat-Sen University, Guangzhou, 510655, China.
- Guangdong Institute of Gastroenterology, Guangzhou, 510655, China.
- Department of General Surgery, The Sixth Affiliated Hospital, Sun Yat-Sen University, Guangzhou, 510655, China.
- Guangdong Provincial Key Laboratory of Colorectal and Pelvic Floor Diseases, The Sixth Affiliated Hospital, Sun Yat-Sen University, Guangzhou, 510655, China.
- Biomedical Innovation Center, The Sixth Affiliated Hospital, Sun Yat-Sen University, Guangzhou, 510655, China.
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8
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Nieminuszczy J, Martin PR, Broderick R, Krwawicz J, Kanellou A, Mocanu C, Bousgouni V, Smith C, Wen KK, Woodward B, Bakal C, Shackley F, Aguilera A, Stewart G, Vyas Y, Niedzwiedz W. Actin nucleators safeguard replication forks by limiting nascent strand degradation. Nucleic Acids Res 2023; 51:6337-6354. [PMID: 37224534 PMCID: PMC10325910 DOI: 10.1093/nar/gkad369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 04/17/2023] [Accepted: 05/11/2023] [Indexed: 05/26/2023] Open
Abstract
Accurate genome replication is essential for all life and a key mechanism of disease prevention, underpinned by the ability of cells to respond to replicative stress (RS) and protect replication forks. These responses rely on the formation of Replication Protein A (RPA)-single stranded (ss) DNA complexes, yet this process remains largely uncharacterized. Here, we establish that actin nucleation-promoting factors (NPFs) associate with replication forks, promote efficient DNA replication and facilitate association of RPA with ssDNA at sites of RS. Accordingly, their loss leads to deprotection of ssDNA at perturbed forks, impaired ATR activation, global replication defects and fork collapse. Supplying an excess of RPA restores RPA foci formation and fork protection, suggesting a chaperoning role for actin nucleators (ANs) (i.e. Arp2/3, DIAPH1) and NPFs (i.e, WASp, N-WASp) in regulating RPA availability upon RS. We also discover that β-actin interacts with RPA directly in vitro, and in vivo a hyper-depolymerizing β-actin mutant displays a heightened association with RPA and the same dysfunctional replication phenotypes as loss of ANs/NPFs, which contrasts with the phenotype of a hyper-polymerizing β-actin mutant. Thus, we identify components of actin polymerization pathways that are essential for preventing ectopic nucleolytic degradation of perturbed forks by modulating RPA activity.
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Affiliation(s)
- Jadwiga Nieminuszczy
- Division of Cancer Biology, The Institute of Cancer Research, London SW3 6JB, UK
| | - Peter R Martin
- Division of Cancer Biology, The Institute of Cancer Research, London SW3 6JB, UK
| | - Ronan Broderick
- Division of Cancer Biology, The Institute of Cancer Research, London SW3 6JB, UK
| | - Joanna Krwawicz
- Division of Cancer Biology, The Institute of Cancer Research, London SW3 6JB, UK
| | - Alexandra Kanellou
- Division of Cancer Biology, The Institute of Cancer Research, London SW3 6JB, UK
| | - Camelia Mocanu
- Division of Cancer Biology, The Institute of Cancer Research, London SW3 6JB, UK
| | - Vicky Bousgouni
- Division of Cancer Biology, The Institute of Cancer Research, London SW3 6JB, UK
| | - Charlotte Smith
- Division of Cancer Biology, The Institute of Cancer Research, London SW3 6JB, UK
| | - Kuo-Kuang Wen
- Department of Pediatrics, Division of Pediatric Hematology-Oncology, Penn State College of Medicine, Penn State Health Children's Hospital, Hershey, PA 17033, USA
| | - Beth L Woodward
- Genome Stability and Human Disease Laboratory, Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham B15 2TT, UK
| | - Chris Bakal
- Division of Cancer Biology, The Institute of Cancer Research, London SW3 6JB, UK
| | - Fiona Shackley
- Paediatric Immunology, Allergy and Infectious Diseases, Sheffield Children's Hospital NHS Foundation Trust, Sheffield, UK
| | - Andrés Aguilera
- Centro Andaluz de Biología Molecular y Medicina Regenerativa CABIMER, Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Seville, Spain
| | - Grant S Stewart
- Genome Stability and Human Disease Laboratory, Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham B15 2TT, UK
| | - Yatin M Vyas
- Department of Pediatrics, Division of Pediatric Hematology-Oncology, Penn State College of Medicine, Penn State Health Children's Hospital, Hershey, PA 17033, USA
| | - Wojciech Niedzwiedz
- Division of Cancer Biology, The Institute of Cancer Research, London SW3 6JB, UK
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9
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Shi J, Hauschulte K, Mikicic I, Maharjan S, Arz V, Strauch T, Heidelberger JB, Schaefer JV, Dreier B, Plückthun A, Beli P, Ulrich HD, Wollscheid HP. Nuclear myosin VI maintains replication fork stability. Nat Commun 2023; 14:3787. [PMID: 37355687 PMCID: PMC10290672 DOI: 10.1038/s41467-023-39517-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Accepted: 06/09/2023] [Indexed: 06/26/2023] Open
Abstract
The actin cytoskeleton is of fundamental importance for cellular structure and plasticity. However, abundance and function of filamentous actin in the nucleus are still controversial. Here we show that the actin-based molecular motor myosin VI contributes to the stabilization of stalled or reversed replication forks. In response to DNA replication stress, myosin VI associates with stalled replication intermediates and cooperates with the AAA ATPase Werner helicase interacting protein 1 (WRNIP1) in protecting these structures from DNA2-mediated nucleolytic attack. Using functionalized affinity probes to manipulate myosin VI levels in a compartment-specific manner, we provide evidence for the direct involvement of myosin VI in the nucleus and against a contribution of the abundant cytoplasmic pool during the replication stress response.
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Affiliation(s)
- Jie Shi
- Institute of Molecular Biology gGmbH (IMB), Ackermannweg 4, D - 55128, Mainz, Germany
| | - Kristine Hauschulte
- Institute of Molecular Biology gGmbH (IMB), Ackermannweg 4, D - 55128, Mainz, Germany
| | - Ivan Mikicic
- Institute of Molecular Biology gGmbH (IMB), Ackermannweg 4, D - 55128, Mainz, Germany
| | - Srijana Maharjan
- Institute of Molecular Biology gGmbH (IMB), Ackermannweg 4, D - 55128, Mainz, Germany
- Mainz Biomed N.V., Robert-Koch-Str. 50, D - 55129, Mainz, Germany
| | - Valerie Arz
- Institute of Molecular Biology gGmbH (IMB), Ackermannweg 4, D - 55128, Mainz, Germany
| | - Tina Strauch
- Institute of Molecular Biology gGmbH (IMB), Ackermannweg 4, D - 55128, Mainz, Germany
| | - Jan B Heidelberger
- Institute of Molecular Biology gGmbH (IMB), Ackermannweg 4, D - 55128, Mainz, Germany
- Max Planck School Matter to Life, Jahnstr. 29, D - 69120, Heidelberg, Germany
| | - Jonas V Schaefer
- University of Zurich, Department of Biochemistry, Winterthurerstr. 190, CH - 8057, Zurich, Switzerland
| | - Birgit Dreier
- University of Zurich, Department of Biochemistry, Winterthurerstr. 190, CH - 8057, Zurich, Switzerland
| | - Andreas Plückthun
- University of Zurich, Department of Biochemistry, Winterthurerstr. 190, CH - 8057, Zurich, Switzerland
| | - Petra Beli
- Institute of Molecular Biology gGmbH (IMB), Ackermannweg 4, D - 55128, Mainz, Germany
- Institute of Developmental Biology and Neurobiology, Johannes Gutenberg University, Hanns-Dieter-Hüsch-Weg 15, D - 55128, Mainz, Germany
| | - Helle D Ulrich
- Institute of Molecular Biology gGmbH (IMB), Ackermannweg 4, D - 55128, Mainz, Germany.
| | - Hans-Peter Wollscheid
- Institute of Molecular Biology gGmbH (IMB), Ackermannweg 4, D - 55128, Mainz, Germany.
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10
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Vieira RC, Pinho LG, Westerberg LS. Understanding immunoactinopathies: A decade of research on WAS gene defects. Pediatr Allergy Immunol 2023; 34:e13951. [PMID: 37102395 DOI: 10.1111/pai.13951] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 03/22/2023] [Accepted: 03/23/2023] [Indexed: 04/28/2023]
Abstract
Immunoactinopathies caused by mutations in actin-related proteins are a growing group of inborn errors of immunity (IEI). Immunoactinopathies are caused by a dysregulated actin cytoskeleton and affect hematopoietic cells especially because of their unique capacity to survey the body for invading pathogens and altered self, such as cancer cells. These cell motility and cell-to-cell interaction properties depend on the dynamic nature of the actin cytoskeleton. Wiskott-Aldrich syndrome (WAS) is the archetypical immunoactinopathy and the first described. WAS is caused by loss-of-function and gain-of-function mutations in the actin regulator WASp, uniquely expressed in hematopoietic cells. Mutations in WAS cause a profound disturbance of actin cytoskeleton regulation of hematopoietic cells. Studies during the last 10 years have shed light on the specific effects on different hematopoietic cells, revealing that they are not affected equally by mutations in the WAS gene. Moreover, the mechanistic understanding of how WASp controls nuclear and cytoplasmatic activities may help to find therapeutic alternatives according to the site of the mutation and clinical phenotypes. In this review, we summarize recent findings that have added to the complexity and increased our understanding of WAS-related diseases and immunoactinopathies.
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Affiliation(s)
- Rhaissa Calixto Vieira
- Department of Microbiology, Tumor and Cell biology, Karolinska Institutet, Stockholm, Sweden
| | - Lia Goncalves Pinho
- Department of Microbiology, Tumor and Cell biology, Karolinska Institutet, Stockholm, Sweden
| | - Lisa S Westerberg
- Department of Microbiology, Tumor and Cell biology, Karolinska Institutet, Stockholm, Sweden
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Palumbieri MD, Merigliano C, Acosta DG, von Känel T, Welter B, Stoy H, Krietsch J, Ulferts S, Sanchi A, Grosse R, Chiolo I, Lopes M. Replication fork plasticity upon replication stress requires rapid nuclear actin polymerization. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.24.534097. [PMID: 36993227 PMCID: PMC10055433 DOI: 10.1101/2023.03.24.534097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Cells rapidly respond to replication stress actively slowing fork progression and inducing fork reversal. How replication fork plasticity is achieved in the context of nuclear organization is currently unknown. Using nuclear actin probes in living and fixed cells, we visualized nuclear actin filaments in unperturbed S phase, rapidly extending in number and thickness upon genotoxic treatments, and taking frequent contact with replication factories. Chemically or genetically impairing nuclear actin polymerization shortly before these treatments prevents active fork slowing and abolishes fork reversal. Defective fork plasticity is linked to reduced recruitment of RAD51 and SMARCAL1 to nascent DNA. Conversely, PRIMPOL gains access to replicating chromatin, promoting unrestrained and discontinuous DNA synthesis, which is associated with increased chromosomal instability and decreased cellular resistance to replication stress. Hence, nuclear F-actin orchestrates replication fork plasticity and is a key molecular determinant in the rapid cellular response to genotoxic treatments.
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