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Sen B, Xie Z, Thomas MD, Pattenden SG, Howard S, McGrath C, Styner M, Uzer G, Furey TS, Rubin J. Nuclear actin structure regulates chromatin accessibility. Nat Commun 2024; 15:4095. [PMID: 38750021 PMCID: PMC11096319 DOI: 10.1038/s41467-024-48580-y] [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: 08/28/2023] [Accepted: 05/07/2024] [Indexed: 05/18/2024] Open
Abstract
Polymerized β-actin may provide a structural basis for chromatin accessibility and actin transport into the nucleus can guide mesenchymal stem cell (MSC) differentiation. Using MSC, we show that using CK666 to inhibit Arp2/3 directed secondary actin branching results in decreased nuclear actin structure, and significantly alters chromatin access measured with ATACseq at 24 h. The ATAC-seq results due to CK666 are distinct from those caused by cytochalasin D (CytoD), which enhances nuclear actin structure. In addition, nuclear visualization shows Arp2/3 inhibition decreases pericentric H3K9me3 marks. CytoD, alternatively, induces redistribution of H3K27me3 marks centrally. Such alterations in chromatin landscape are consistent with differential gene expression associated with distinctive differentiation patterns. Further, knockdown of the non-enzymatic monomeric actin binding protein, Arp4, leads to extensive chromatin unpacking, but only a modest increase in transcription, indicating an active role for actin-Arp4 in transcription. These data indicate that dynamic actin remodeling can regulate chromatin interactions.
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Affiliation(s)
- Buer Sen
- Department of Medicine, University of North Carolina, Chapel Hill, NC, USA
| | - Zhihui Xie
- Department of Medicine, University of North Carolina, Chapel Hill, NC, USA
| | - Michelle D Thomas
- Division of Chemical Biology and Medicinal Chemistry, Center for Integrative Chemical Biology and Drug Discovery, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Samantha G Pattenden
- Division of Chemical Biology and Medicinal Chemistry, Center for Integrative Chemical Biology and Drug Discovery, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Sean Howard
- Department of Mechanical and Biomedical Engineering, Boise State University, Boise, ID, USA
| | - Cody McGrath
- Department of Medicine, University of North Carolina, Chapel Hill, NC, USA
| | - Maya Styner
- Department of Medicine, University of North Carolina, Chapel Hill, NC, USA
| | - Gunes Uzer
- Department of Mechanical and Biomedical Engineering, Boise State University, Boise, ID, USA
| | - Terrence S Furey
- Departments of Genetics and Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Janet Rubin
- Department of Medicine, University of North Carolina, Chapel Hill, NC, USA.
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2
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Verma N, Renauer PA, Dong C, Xin S, Lin Q, Zhang F, Glazer PM, Chen S. Genome scale CRISPR screens identify actin capping proteins as key modulators of therapeutic responses to radiation and immunotherapy. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.14.575614. [PMID: 38293095 PMCID: PMC10827061 DOI: 10.1101/2024.01.14.575614] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
Radiotherapy (RT), is a fundamental treatment for malignant tumors and is used in over half of cancer patients. As radiation can promote anti-tumor immune effects, a promising therapeutic strategy is to combine radiation with immune checkpoint inhibitors (ICIs). However, the genetic determinants that impact therapeutic response in the context of combination therapy with radiation and ICI have not been systematically investigated. To unbiasedly identify the tumor intrinsic genetic factors governing such responses, we perform a set of genome-scale CRISPR screens in melanoma cells for cancer survival in response to low-dose genotoxic radiation treatment, in the context of CD8 T cell co-culture and with anti-PD1 checkpoint blockade antibody. Two actin capping proteins, Capza3 and Capg, emerge as top hits that upon inactivation promote the survival of melanoma cells in such settings. Capza3 and Capg knockouts (KOs) in mouse and human cancer cells display persistent DNA damage due to impaired homology directed repair (HDR); along with increased radiation, chemotherapy, and DNA repair inhibitor sensitivity. However, when cancer cells with these genes inactivated were exposed to sublethal radiation, inactivation of such actin capping protein promotes activation of the STING pathway, induction of inhibitory CEACAM1 ligand expression and resistance to CD8 T cell killing. Patient cancer genomics analysis reveals an increased mutational burden in patients with inactivating mutations in CAPG and/or CAPZA3, at levels comparable to other HDR associated genes. There is also a positive correlation between CAPG expression and activation of immune related pathways and CD8 T cell tumor infiltration. Our results unveil the critical roles of actin binding proteins for efficient HDR within cancer cells and demonstrate a previously unrecognized regulatory mechanism of therapeutic response to radiation and immunotherapy.
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Affiliation(s)
- Nipun Verma
- Department of Genetics, Yale University School of Medicine, New Haven, Connecticut, USA
- System Biology Institute, Yale University, West Haven, Connecticut, USA
- Department of Therapeutic Radiology, Yale University, New Haven, Connecticut, USA
| | - Paul A. Renauer
- Department of Genetics, Yale University School of Medicine, New Haven, Connecticut, USA
- System Biology Institute, Yale University, West Haven, Connecticut, USA
| | - Chuanpeng Dong
- Department of Genetics, Yale University School of Medicine, New Haven, Connecticut, USA
- System Biology Institute, Yale University, West Haven, Connecticut, USA
| | - Shan Xin
- Department of Genetics, Yale University School of Medicine, New Haven, Connecticut, USA
- System Biology Institute, Yale University, West Haven, Connecticut, USA
| | - Qianqian Lin
- Department of Genetics, Yale University School of Medicine, New Haven, Connecticut, USA
- System Biology Institute, Yale University, West Haven, Connecticut, USA
| | - Feifei Zhang
- Department of Genetics, Yale University School of Medicine, New Haven, Connecticut, USA
- System Biology Institute, Yale University, West Haven, Connecticut, USA
| | - Peter M. Glazer
- Department of Therapeutic Radiology, Yale University, New Haven, Connecticut, USA
- Yale Comprehensive Cancer Center, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Sidi Chen
- Department of Genetics, Yale University School of Medicine, New Haven, Connecticut, USA
- System Biology Institute, Yale University, West Haven, Connecticut, USA
- Immunobiology Program, Yale University, New Haven, Connecticut, USA
- Molecular Cell Biology, Genetics, and Development Program, Yale University, New Haven, Connecticut, USA
- Yale Comprehensive Cancer Center, Yale University School of Medicine, New Haven, Connecticut, USA
- Yale Stem Cell Center, Yale University School of Medicine, New Haven, Connecticut, USA
- Yale Center for Biomedical Data Science, Yale University School of Medicine, New Haven, Connecticut, USA
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3
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Cobb AM, De Silva SA, Hayward R, Sek K, Ulferts S, Grosse R, Shanahan CM. Filamentous nuclear actin regulation of PML NBs during the DNA damage response is deregulated by prelamin A. Cell Death Dis 2022; 13:1042. [PMID: 36522328 PMCID: PMC9755150 DOI: 10.1038/s41419-022-05491-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 11/28/2022] [Accepted: 12/01/2022] [Indexed: 12/16/2022]
Abstract
Nuclear actin participates in a continuously expanding list of core processes within eukaryotic nuclei, including the maintenance of genomic integrity. In response to DNA damage, nuclear actin polymerises into filaments that are involved in the repair of damaged DNA through incompletely defined mechanisms. We present data to show that the formation of nuclear F-actin in response to genotoxic stress acts as a scaffold for PML NBs and that these filamentous networks are essential for PML NB fission and recruitment of microbodies to DNA lesions. Further to this, we demonstrate that the accumulation of the toxic lamin A precursor prelamin A induces mislocalisation of nuclear actin to the nuclear envelope and prevents the establishment of nucleoplasmic F-actin networks in response to stress. Consequently, PML NB dynamics and recruitment to DNA lesions is ablated, resulting in impaired DNA damage repair. Inhibition of nuclear export of formin mDia2 restores nuclear F-actin formation by augmenting polymerisation of nuclear actin in response to stress and rescues PML NB localisation to sites of DNA repair, leading to reduced levels of DNA damage.
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Affiliation(s)
- Andrew M. Cobb
- grid.13097.3c0000 0001 2322 6764BHF Centre of Research Excellence, School of Cardiovascular Medicine and Sciences, King’s College London, The James Black Centre, 125 Coldharbour Lane, London, SE5 9NU United Kingdom
| | - Shanelle A. De Silva
- grid.13097.3c0000 0001 2322 6764BHF Centre of Research Excellence, School of Cardiovascular Medicine and Sciences, King’s College London, The James Black Centre, 125 Coldharbour Lane, London, SE5 9NU United Kingdom
| | - Robert Hayward
- grid.13097.3c0000 0001 2322 6764BHF Centre of Research Excellence, School of Cardiovascular Medicine and Sciences, King’s College London, The James Black Centre, 125 Coldharbour Lane, London, SE5 9NU United Kingdom
| | - Karolina Sek
- grid.13097.3c0000 0001 2322 6764BHF Centre of Research Excellence, School of Cardiovascular Medicine and Sciences, King’s College London, The James Black Centre, 125 Coldharbour Lane, London, SE5 9NU United Kingdom
| | - Svenja Ulferts
- grid.5963.9Institute of Experimental and Clinical Pharmacology and Toxicology, Medical Faculty, University of Freiburg, Albertstraße 25, 79104 Freiburg, Germany
| | - Robert Grosse
- grid.5963.9Institute of Experimental and Clinical Pharmacology and Toxicology, Medical Faculty, University of Freiburg, Albertstraße 25, 79104 Freiburg, Germany
| | - Catherine M. Shanahan
- grid.13097.3c0000 0001 2322 6764BHF Centre of Research Excellence, School of Cardiovascular Medicine and Sciences, King’s College London, The James Black Centre, 125 Coldharbour Lane, London, SE5 9NU United Kingdom
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4
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Rubin J, van Wijnen AJ, Uzer G. Architectural control of mesenchymal stem cell phenotype through nuclear actin. Nucleus 2022; 13:35-48. [PMID: 35133922 PMCID: PMC8837231 DOI: 10.1080/19491034.2022.2029297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Revised: 01/10/2022] [Accepted: 01/11/2022] [Indexed: 11/18/2022] Open
Abstract
There is growing appreciation that architectural components of the nucleus regulate gene accessibility by altering chromatin organization. While nuclear membrane connector proteins link the mechanosensitive actin cytoskeleton to the nucleoskeleton, actin's contribution to the inner architecture of the nucleus remains enigmatic. Control of actin transport into the nucleus, plus the presence of proteins that control actin structure (the actin tool-box) within the nucleus, suggests that nuclear actin may support biomechanical regulation of gene expression. Cellular actin structure is mechanoresponsive: actin cables generated through forces experienced at the plasma membrane transmit force into the nucleus. We posit that dynamic actin remodeling in response to such biomechanical cues provides a novel level of structural control over the epigenetic landscape. We here propose to bring awareness to the fact that mechanical forces can promote actin transfer into the nucleus and control structural arrangements as illustrated in mesenchymal stem cells, thereby modulating lineage commitment.
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Affiliation(s)
- Janet Rubin
- Department of Medicine, University of North Carolina, Chapel Hill, NC, USA
| | - Andre J. van Wijnen
- Department of Biochemistry, University of Vermont Medical School, Burlington, Vt, USA
| | - Gunes Uzer
- Department of Mechanical & Biomedical Engineering, Boise State University, Boise, ID, USA
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5
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Rubin J, Styner M. The skeleton in a physical world. Exp Biol Med (Maywood) 2022; 247:2213-2222. [PMID: 35983849 PMCID: PMC9899984 DOI: 10.1177/15353702221113861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
All organisms exist within a physical space and respond to physical forces as part of daily life. In higher organisms, the skeleton is critical for locomotion in the physical environment, providing a carapace upon which the animal can move to accomplish functions necessary for living. As such, the skeleton has responded evolutionarily, and does in real-time, to physical stresses placed on it to ensure that its structure supports its function in the sea, in the air, and on dry land. In this article, we consider how those cells responsible for remodeling skeletal structure respond to mechanical force including load magnitude, frequency, and cyclicity, and how force rearranges cellular structure in turn. The effects of these forces to balance the mesenchymal stem cell supply of bone-forming osteoblasts and energy storing adipocytes are addressed. That this phenotypic switching is achieved at the level of both gene transactivation and alteration of structural epigenetic controls of gene expression is considered. Finally, as clinicians, we consider this information as it applies to a prescriptive for intelligent exercise.
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Özkan H, Öztürk DG, Korkmaz G. Transcriptional Factor Repertoire of Breast Cancer in 3D Cell Culture Models. Cancers (Basel) 2022; 14:cancers14041023. [PMID: 35205770 PMCID: PMC8870600 DOI: 10.3390/cancers14041023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 02/13/2022] [Accepted: 02/14/2022] [Indexed: 02/04/2023] Open
Abstract
Simple Summary Knowledge of the transcriptional regulation of breast cancer tumorigenesis is largely based on studies performed in two-dimensional (2D) monolayer culture models, which lack tissue architecture and therefore fail to represent tumor heterogeneity. However, three-dimensional (3D) cell culture models are better at mimicking in vivo tumor microenvironment, which is critical in regulating cellular behavior. Hence, 3D cell culture models hold great promise for translational breast cancer research. Abstract Intratumor heterogeneity of breast cancer is driven by extrinsic factors from the tumor microenvironment (TME) as well as tumor cell–intrinsic parameters including genetic, epigenetic, and transcriptomic traits. The extracellular matrix (ECM), a major structural component of the TME, impacts every stage of tumorigenesis by providing necessary biochemical and biomechanical cues that are major regulators of cell shape/architecture, stiffness, cell proliferation, survival, invasion, and migration. Moreover, ECM and tissue architecture have a profound impact on chromatin structure, thereby altering gene expression. Considering the significant contribution of ECM to cellular behavior, a large body of work underlined that traditional two-dimensional (2D) cultures depriving cell–cell and cell–ECM interactions as well as spatial cellular distribution and organization of solid tumors fail to recapitulate in vivo properties of tumor cells residing in the complex TME. Thus, three-dimensional (3D) culture models are increasingly employed in cancer research, as these culture systems better mimic the physiological microenvironment and shape the cellular responses according to the microenvironmental cues that will regulate critical cell functions such as cell shape/architecture, survival, proliferation, differentiation, and drug response as well as gene expression. Therefore, 3D cell culture models that better resemble the patient transcriptome are critical in defining physiologically relevant transcriptional changes. This review will present the transcriptional factor (TF) repertoire of breast cancer in 3D culture models in the context of mammary tissue architecture, epithelial-to-mesenchymal transition and metastasis, cell death mechanisms, cancer therapy resistance and differential drug response, and stemness and will discuss the impact of culture dimensionality on breast cancer research.
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Affiliation(s)
- Hande Özkan
- School of Medicine, Koç University, Istanbul 34450, Turkey;
- Research Centre for Translational Medicine (KUTTAM), Koç University, Istanbul 34450, Turkey
| | - Deniz Gülfem Öztürk
- School of Medicine, Koç University, Istanbul 34450, Turkey;
- Research Centre for Translational Medicine (KUTTAM), Koç University, Istanbul 34450, Turkey
- Correspondence: (D.G.Ö.); (G.K.)
| | - Gozde Korkmaz
- School of Medicine, Koç University, Istanbul 34450, Turkey;
- Research Centre for Translational Medicine (KUTTAM), Koç University, Istanbul 34450, Turkey
- Correspondence: (D.G.Ö.); (G.K.)
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7
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Sen B, Xie Z, Howard S, Styner M, van Wijnen AJ, Uzer G, Rubin J. Mechanically Induced Nuclear Shuttling of β-Catenin Requires Co-transfer of Actin. Stem Cells 2022; 40:423-434. [PMID: 35278073 PMCID: PMC9633329 DOI: 10.1093/stmcls/sxac006] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 01/27/2022] [Indexed: 11/15/2022]
Abstract
Mesenchymal stem cells (MSCs) respond to environmental forces with both cytoskeletal re-structuring and activation of protein chaperones of mechanical information, β-catenin, and yes-associated protein 1 (YAP1). To function, MSCs must differentiate between dynamic forces such as cyclic strains of extracellular matrix due to physical activity and static strains due to ECM stiffening. To delineate how MSCs recognize and respond differently to both force types, we compared effects of dynamic (200 cycles × 2%) and static (1 × 2% hold) strain on nuclear translocation of β-catenin and YAP1 at 3 hours after force application. Dynamic strain induced nuclear accumulation of β-catenin, and increased cytoskeletal actin structure and cell stiffness, but had no effect on nuclear YAP1 levels. Critically, both nuclear actin and nuclear stiffness increased along with dynamic strain-induced β-catenin transport. Augmentation of cytoskeletal structure using either static strain or lysophosphatidic acid did not increase nuclear content of β-catenin or actin, but induced robust nuclear increase in YAP1. As actin binds β-catenin, we considered whether β-catenin, which lacks a nuclear localization signal, was dependent on actin to gain entry to the nucleus. Knockdown of cofilin-1 (Cfl1) or importin-9 (Ipo9), which co-mediate nuclear transfer of G-actin, prevented dynamic strain-mediated nuclear transfer of both β-catenin and actin. In sum, dynamic strain induction of actin re-structuring promotes nuclear transport of G-actin, concurrently supporting nuclear access of β-catenin via mechanisms used for actin transport. Thus, dynamic and static strain activate alternative mechanoresponses reflected by differences in the cellular distributions of actin, β-catenin, and YAP1.
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Affiliation(s)
- Buer Sen
- Department of Medicine, University of North Carolina, Chapel Hill, NC, USA
| | - Zhihui Xie
- Department of Medicine, University of North Carolina, Chapel Hill, NC, USA
| | - Sean Howard
- Department of Mechanical and Biomedical Engineering, Boise State University, Boise, ID, USA
| | - Maya Styner
- Department of Medicine, University of North Carolina, Chapel Hill, NC, USA
| | - Andre J van Wijnen
- Department of Biochemistry, University of Vermont Medical School, Burlington, VT, USA
| | - Gunes Uzer
- Department of Mechanical and Biomedical Engineering, Boise State University, Boise, ID, USA
| | - Janet Rubin
- Corresponding author: Janet Rubin, Department of Medicine, University of North Carolina, Chapel Hill, NC 27599, USA.
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8
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New Insights into Cellular Functions of Nuclear Actin. BIOLOGY 2021; 10:biology10040304. [PMID: 33916969 PMCID: PMC8067577 DOI: 10.3390/biology10040304] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 03/30/2021] [Accepted: 04/01/2021] [Indexed: 12/12/2022]
Abstract
Simple Summary It is well known that actin forms a cytoplasmic network of microfilaments, the part of the cytoskeleton, in the cytoplasm of eukaryotic cells. The presence of nuclear actin was elusive for a very long time. Now, there is a very strong evidence that actin plays many important roles in the nucleus. Here, we discuss the recently discovered functions of the nuclear actin pool. Actin does not have nuclear localization signal (NLS), so its import to the nucleus is facilitated by the NLS-containing proteins. Nuclear actin plays a role in the maintenance of the nuclear structure and the nuclear envelope breakdown. It is also involved in chromatin remodeling, and chromatin and nucleosome movement necessary for DNA recombination, repair, and the initiation of transcription. It also binds RNA polymerases, promoting transcription. Because of the multifaceted role of nuclear actin, the future challenge will be to further define its functions in various cellular processes and diseases. Abstract Actin is one of the most abundant proteins in eukaryotic cells. There are different pools of nuclear actin often undetectable by conventional staining and commercial antibodies used to identify cytoplasmic actin. With the development of more sophisticated imaging and analytical techniques, it became clear that nuclear actin plays a crucial role in shaping the chromatin, genomic, and epigenetic landscape, transcriptional regulation, and DNA repair. This multifaceted role of nuclear actin is not only important for the function of the individual cell but also for the establishment of cell fate, and tissue and organ differentiation during development. Moreover, the changes in the nuclear, chromatin, and genomic architecture are preamble to various diseases. Here, we discuss some of the newly described functions of nuclear actin.
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9
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Sankaran J, Uzer G, van Wijnen AJ, Rubin J. Gene regulation through dynamic actin control of nuclear structure. Exp Biol Med (Maywood) 2019; 244:1345-1353. [PMID: 31084213 DOI: 10.1177/1535370219850079] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Bone marrow mesenchymal stem cells exist in a multipotential state, where osteogenic and adipogenic genomes are silenced in heterochromatin at the inner nuclear leaflet. Physical force, generated in the marrow space during dynamic exercise exerts control overexpression of differentiation. Mesenchymal stem cells experience mechanical force through their cytoskeletal attachments to substrate, inducing signaling that alters gene expression. The generated force is further transferred from the cytoskeleton to the nucleoskeleton through tethering of actin to Linker of Nucleus and Cytoskeleton (LINC) complexes. Forces exerted on LINC alter the shape and placement of the nucleus within the cell, and are ultimately transferred into the nucleus. LINC complexes transverse the nuclear membrane and connect to the internal nucleoskeleton that is made up of lamin filaments and actin. Force transfer through LINC thus causes structural rearrangements of the nuclear scaffolding upon which chromosomes are arranged. Gene availability is not only modulated through heterochromatin remodeling enzymes and active transcription factors but also by control of nucleoskeletal structure and nuclear enzymes that mediate actin polymerization in the nucleus. Nuclear actin structure may be affected by similar force-activated pathways as those controlling the cytoplasmic actin cytoskeleton and represent a critical determinant of mesenchymal stem cell lineage commitment. Impact statement Gene expression is controlled by nuclear structure which is modulated by both internal and external forces exerted on the nucleoskeleton. Extracellular forces experienced through the actin cytoskeleton are transmitted to the internal nucleoskeleton via Linker of Nucleus and Cytoskeleton (LINC) protein connections. LINC complexes directly alter nuclear shape and entry of molecules that regulate transcription. New mechanistic models indicate that nuclear actin is a dynamic component of the filamentous nucleoskeleton and modified by an intranuclear “actin toolbox”, a set of enzymes that regulate linear and branched polymerization of nuclear actin. External stimulation of both biomechanical and biochemical pathways alters nuclear actin structure and has profound effects on gene expression by controlling chromatin architecture and transcription factor access to gene targets. The available data indicate that nucleoskeletal control of gene expression is critical for self-renewal and mesenchymal lineage-allocation in stem cells.
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Affiliation(s)
- Jeyantt Sankaran
- Department of Medicine, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Gunes Uzer
- College of Mechanical and Biomedical Engineering, Boise State University, Boise, ID 83725, USA
| | - Andre J van Wijnen
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN 55905, USA.,Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55905, USA
| | - Janet Rubin
- Department of Medicine, University of North Carolina, Chapel Hill, NC 27599, USA
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10
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Hurst V, Shimada K, Gasser SM. Nuclear Actin and Actin-Binding Proteins in DNA Repair. Trends Cell Biol 2019; 29:462-476. [PMID: 30954333 DOI: 10.1016/j.tcb.2019.02.010] [Citation(s) in RCA: 81] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Revised: 02/25/2019] [Accepted: 02/26/2019] [Indexed: 12/27/2022]
Abstract
Nuclear actin has been implicated in a variety of DNA-related processes including chromatin remodeling, transcription, replication, and DNA repair. However, the mechanistic understanding of actin in these processes has been limited, largely due to a lack of research tools that address the roles of nuclear actin specifically, that is, distinct from its cytoplasmic functions. Recent findings support a model for homology-directed DNA double-strand break (DSB) repair in which a complex of ARP2 and ARP3 (actin-binding proteins 2 and 3) binds at the break and works with actin to promote DSB clustering and homology-directed repair. Further, it has been reported that relocalization of heterochromatic DSBs to the nuclear periphery in Drosophila is ARP2/3 dependent and actin-myosin driven. Here we provide an overview of the role of nuclear actin and actin-binding proteins in DNA repair, critically evaluating the experimental tools used and potential indirect effects.
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Affiliation(s)
- Verena Hurst
- Friedrich Miescher Institute for Biomedical Research, CH-4058 Basel, Switzerland; University of Basel, Faculty of Natural Sciences, CH-4056 Basel, Switzerland
| | - Kenji Shimada
- Friedrich Miescher Institute for Biomedical Research, CH-4058 Basel, Switzerland
| | - Susan M Gasser
- Friedrich Miescher Institute for Biomedical Research, CH-4058 Basel, Switzerland; University of Basel, Faculty of Natural Sciences, CH-4056 Basel, Switzerland.
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11
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Reis-Sobreiro M, Chen JF, Novitskaya T, You S, Morley S, Steadman K, Gill NK, Eskaros A, Rotinen M, Chu CY, Chung LWK, Tanaka H, Yang W, Knudsen BS, Tseng HR, Rowat AC, Posadas EM, Zijlstra A, Di Vizio D, Freeman MR. Emerin Deregulation Links Nuclear Shape Instability to Metastatic Potential. Cancer Res 2018; 78:6086-6097. [PMID: 30154147 DOI: 10.1158/0008-5472.can-18-0608] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Revised: 06/13/2018] [Accepted: 08/22/2018] [Indexed: 01/21/2023]
Abstract
Abnormalities in nuclear shape are a well-known feature of cancer, but their contribution to malignant progression remains poorly understood. Here, we show that depletion of the cytoskeletal regulator, Diaphanous-related formin 3 (DIAPH3), or the nuclear membrane-associated proteins, lamin A/C, in prostate and breast cancer cells, induces nuclear shape instability, with a corresponding gain in malignant properties, including secretion of extracellular vesicles that contain genomic material. This transformation is characterized by a reduction and/or mislocalization of the inner nuclear membrane protein, emerin. Consistent with this, depletion of emerin evokes nuclear shape instability and promotes metastasis. By visualizing emerin localization, evidence for nuclear shape instability was observed in cultured tumor cells, in experimental models of prostate cancer, in human prostate cancer tissues, and in circulating tumor cells from patients with metastatic disease. Quantitation of emerin mislocalization discriminated cancer from benign tissue and correlated with disease progression in a prostate cancer cohort. Taken together, these results identify emerin as a mediator of nuclear shape stability in cancer and show that destabilization of emerin can promote metastasis.Significance: This study identifies a novel mechanism integrating the control of nuclear structure with the metastatic phenotype, and our inclusion of two types of human specimens (cancer tissues and circulating tumor cells) demonstrates direct relevance to human cancer.Graphical Abstract: http://cancerres.aacrjournals.org/content/canres/78/21/6086/F1.large.jpg Cancer Res; 78(21); 6086-97. ©2018 AACR.
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Affiliation(s)
- Mariana Reis-Sobreiro
- Division of Cancer Biology and Therapeutics, Department of Surgery and Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, California
| | - Jie-Fu Chen
- Division of Cancer Biology and Therapeutics, Department of Surgery and Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, California
| | - Tatiana Novitskaya
- Department of Pathology, Microbiology and Immunology, Vanderbilt University, Nashville, Tennessee
| | - Sungyong You
- Division of Cancer Biology and Therapeutics, Department of Surgery and Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, California
| | - Samantha Morley
- Division of Cancer Biology and Therapeutics, Department of Surgery and Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, California
| | - Kenneth Steadman
- Division of Cancer Biology and Therapeutics, Department of Surgery and Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, California
| | - Navjot Kaur Gill
- Department of Integrative Biology and Physiology, University of California, Los Angeles, California
| | - Adel Eskaros
- Department of Pathology, Microbiology and Immunology, Vanderbilt University, Nashville, Tennessee
| | - Mirja Rotinen
- Division of Cancer Biology and Therapeutics, Department of Surgery and Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, California
| | - Chia-Yi Chu
- Urologic Oncology Program/Uro-Oncology Research Laboratories, Samuel Oschin Comprehensive Center Institute, Cedars-Sinai Medical Center, Los Angeles, California.,Division of Hematology/Oncology, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California
| | - Leland W K Chung
- Urologic Oncology Program/Uro-Oncology Research Laboratories, Samuel Oschin Comprehensive Center Institute, Cedars-Sinai Medical Center, Los Angeles, California.,Division of Hematology/Oncology, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California
| | - Hisashi Tanaka
- Division of Cancer Biology and Therapeutics, Department of Surgery and Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, California
| | - Wei Yang
- Division of Cancer Biology and Therapeutics, Department of Surgery and Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, California
| | - Beatrice S Knudsen
- Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, California.,Department of Pathology and Laboratory Medicine, Cedars-Sinai Medical Center, Los Angeles, California
| | - Hsian-Rong Tseng
- Department of Molecular and Medical Pharmacology, University of California, Los Angeles, California
| | - Amy C Rowat
- Department of Integrative Biology and Physiology, University of California, Los Angeles, California
| | - Edwin M Posadas
- Urologic Oncology Program/Uro-Oncology Research Laboratories, Samuel Oschin Comprehensive Center Institute, Cedars-Sinai Medical Center, Los Angeles, California.,Division of Hematology/Oncology, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California
| | - Andries Zijlstra
- Department of Pathology, Microbiology and Immunology, Vanderbilt University, Nashville, Tennessee.,Vanderbilt-Ingram Cancer Center, Nashville, Tennessee
| | - Dolores Di Vizio
- Department of Pathology and Laboratory Medicine, Cedars-Sinai Medical Center, Los Angeles, California
| | - Michael R Freeman
- Division of Cancer Biology and Therapeutics, Department of Surgery and Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, California.
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12
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An actin-based nucleoskeleton involved in gene regulation and genome organization. Biochem Biophys Res Commun 2018; 506:378-386. [DOI: 10.1016/j.bbrc.2017.11.206] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2017] [Accepted: 11/30/2017] [Indexed: 12/21/2022]
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13
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Plessner M, Grosse R. Dynamizing nuclear actin filaments. Curr Opin Cell Biol 2018; 56:1-6. [PMID: 30193156 DOI: 10.1016/j.ceb.2018.08.005] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2018] [Revised: 08/16/2018] [Accepted: 08/16/2018] [Indexed: 12/19/2022]
Abstract
While it is long known that actin is part of the nuclear proteome, its properties and functions as regulated, functional and dynamically assembled actin filaments are only recently emerging. Thus, newly uncovered roles for intranuclear actin filaments are opening new perspectives on how the nucleus and its genomic content may be organized in particular with regard to a given stage of the cell cycle. Here, we summarize recent studies on actin filament polymerization and turnover within the nuclear compartment of mammalian cells. We emphasize and discuss novel findings, in which transient and dynamic nuclear actin filaments have been visualized in physiological contexts, and focus on aspects of signalling mechanisms, chromatin reorganization and DNA repair. Further, a better understanding of the spatiotemporal control of nuclear actin-regulating factors in mammalian cells will ultimately provide a more detailed view on how the nuclear F-actin cytoskeleton contributes to genome organization and nuclear architecture.
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Affiliation(s)
- Matthias Plessner
- Institute of Pharmacology, Medical Faculty, University of Marburg, Karl-von-Frisch-Str. 2, 35043 Marburg, Germany
| | - Robert Grosse
- Institute of Pharmacology, Medical Faculty, University of Marburg, Karl-von-Frisch-Str. 2, 35043 Marburg, Germany.
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14
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Seifert A, Posern G. Tightly controlled MRTF-A activity regulates epithelial differentiation during formation of mammary acini. Breast Cancer Res 2017; 19:68. [PMID: 28592291 PMCID: PMC5463372 DOI: 10.1186/s13058-017-0860-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Accepted: 05/25/2017] [Indexed: 01/06/2023] Open
Abstract
Background Myocardin-related transcription factors (MRTF) A and B link actin dynamics and mechanotransduction to gene expression. In mice, MRTF-A is involved in mammary gland differentiation, but its role in human mammary epithelial cells remains unclear. Methods Three-dimensional cultures of human mammary epithelial MCF10A cells were used to model acinar morphogenesis. Stable MRTF-A knockdown, MRTF-A/B rescue and MRTF-A/B overexpression was established to characterize the functional role during morphogenesis using confocal microscopy and expression analysis. Breast cancer patient databases were analyzed for MRTF-A expression. Results We showed that a precise temporal control of MRTFs is required for normal morphogenesis of MCF10A mammary acini. MRTF transcriptional activity, but not their protein amounts, is transiently induced during 3D acini formation. MRTF-A knockdown dramatically reduces acini size and prevents lumen formation. These effects are rescued by re-expression of MRTF-A, and partially by MRTF-B. Conversely, overexpression of MRTF-A and MRTF-B increases acini size, resulting in irregular spheroids without lumen and defective apico-basal polarity. These phenotypes correlate with deregulated expression of cell cycle inhibitors p21/Waf1, p27/Kip1 and altered phosphorylation of retinoblastoma protein. In MRTF overexpressing spheroids, proliferation and apoptosis are simultaneously increased at late stages, whilst neither occurs in control acini. MRTFs interfere with anoikis of the inner cells and cause an integrin switch from α6 to α5, repression of E-cadherin and induction of mesenchymal markers vimentin, Snai2 and Zeb1. Moreover, MRTF-overexpressing spheroids are insensitive to alteration in matrix stiffness. In two breast cancer cohorts, high expression of MRTF-A and known target genes was associated with decreased patient survival. Conclusion MRTF-A is required for proliferation and formation of mammary acini from luminal epithelial cells. Conversely, elevated MRTF activity results in pre-malignant spheroid formation due to defective proliferation, polarity loss and epithelial-mesenchymal transition. Electronic supplementary material The online version of this article (doi:10.1186/s13058-017-0860-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Anja Seifert
- Institute for Physiological Chemistry, Medical Faculty, Martin Luther University Halle-Wittenberg, 06114, Halle (Saale), Germany
| | - Guido Posern
- Institute for Physiological Chemistry, Medical Faculty, Martin Luther University Halle-Wittenberg, 06114, Halle (Saale), Germany.
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15
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Sen B, Uzer G, Samsonraj RM, Xie Z, McGrath C, Styner M, Dudakovic A, van Wijnen AJ, Rubin J. Intranuclear Actin Structure Modulates Mesenchymal Stem Cell Differentiation. Stem Cells 2017; 35:1624-1635. [PMID: 28371128 DOI: 10.1002/stem.2617] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Revised: 02/19/2017] [Accepted: 03/10/2017] [Indexed: 01/05/2023]
Abstract
Actin structure contributes to physiologic events within the nucleus to control mesenchymal stromal cell (MSC) differentiation. Continuous cytochalasin D (Cyto D) disruption of the MSC actin cytoskeleton leads to osteogenic or adipogenic differentiation, both requiring mass transfer of actin into the nucleus. Cyto D remains extranuclear, thus intranuclear actin polymerization is potentiated by actin transfer: we asked whether actin structure affects differentiation. We show that secondary actin filament branching via the Arp2/3 complex is required for osteogenesis and that preventing actin branching stimulates adipogenesis, as shown by expression profiling of osteogenic and adipogenic biomarkers and unbiased RNA-seq analysis. Mechanistically, Cyto D activates osteoblast master regulators (e.g., Runx2, Sp7, Dlx5) and novel coregulated genes (e.g., Atoh8, Nr4a3, Slfn5). Formin-induced primary actin filament formation is critical for Arp2/3 complex recruitment: osteogenesis is prevented by silencing of the formin mDia1, but not its paralog mDia2. Furthermore, while inhibition of actin, branching is a potent adipogenic stimulus, silencing of either mDia1 or mDia2 blocks adipogenic gene expression. We propose that mDia1, which localizes in the cytoplasm of multipotential MSCs and traffics into the nucleus after cytoskeletal disruption, joins intranuclear mDia2 to facilitate primary filament formation before mediating subsequent branching via Arp2/3 complex recruitment. The resulting intranuclear branched actin network specifies osteogenic differentiation, while actin polymerization in the absence of Arp2/3 complex-mediated secondary branching causes adipogenic differentiation. Stem Cells 2017;35:1624-1635.
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Affiliation(s)
- Buer Sen
- Department of Medicine, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Gunes Uzer
- Department of Medicine, University of North Carolina, Chapel Hill, North Carolina, USA.,Department of Mechanical/Biomedical Engineering, Boise State University, Boise, Idaho, USA
| | - Rebekah M Samsonraj
- Department of Orthopedic Surgery and Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota, USA
| | - Zhihui Xie
- Department of Medicine, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Cody McGrath
- Department of Medicine, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Maya Styner
- Department of Medicine, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Amel Dudakovic
- Department of Orthopedic Surgery and Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota, USA
| | - Andre J van Wijnen
- Department of Orthopedic Surgery and Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota, USA
| | - Janet Rubin
- Department of Medicine, University of North Carolina, Chapel Hill, North Carolina, USA.,Department of Pharmacology, University of North Carolina, Chapel Hill, North Carolina, USA
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16
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RUBIN JANET, SEN BUER. Actin up in the Nucleus: Regulation of Actin Structures Modulates Mesenchymal Stem Cell Differentiation. TRANSACTIONS OF THE AMERICAN CLINICAL AND CLIMATOLOGICAL ASSOCIATION 2017; 128:180-192. [PMID: 28790502 PMCID: PMC5525393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Stem cells respond to environmental signals that induce their differentiation to cells that make up specialized tissues and organs. Our laboratory has focused on bone marrow mesenchymal stem cells (MSCs) that supply bone osteoblasts and marrow adipocytes, an output that appears to be reciprocal. Case in point: exercise promotes osteogenesis and bone formation, and inhibits marrow adipose accrual. A mechanically induced signal pathway concentrating on preserving β-catenin also causes increased structure of the actin cytoskeleton, both of which inhibit adipogenesis. Recently we showed that intranuclear actin is as important to MSC lineage decisions as cytoplasmic actin. This opens up new areas for understanding gene expression in stem cells.
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Affiliation(s)
- JANET RUBIN
- Correspondence and reprint requests: Janet Rubin, UNC School of Medicine,
5030 Burnette-Womack, CB #7170, Chapel Hill, North Carolina 27599919-966-6744
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17
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Sen B, Xie Z, Uzer G, Thompson WR, Styner M, Wu X, Rubin J. Intranuclear Actin Regulates Osteogenesis. Stem Cells 2016; 33:3065-76. [PMID: 26140478 DOI: 10.1002/stem.2090] [Citation(s) in RCA: 89] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Revised: 06/02/2015] [Accepted: 06/06/2015] [Indexed: 12/22/2022]
Abstract
Depolymerization of the actin cytoskeleton induces nuclear trafficking of regulatory proteins and global effects on gene transcription. We here show that in mesenchymal stem cells (MSCs), cytochalasin D treatment causes rapid cofilin-/importin-9-dependent transfer of G-actin into the nucleus. The continued presence of intranuclear actin, which forms rod-like structures that stain with phalloidin, is associated with induction of robust expression of the osteogenic genes osterix and osteocalcin in a Runx2-dependent manner, and leads to acquisition of osteogenic phenotype. Adipogenic differentiation also occurs, but to a lesser degree. Intranuclear actin leads to nuclear export of Yes-associated protein (YAP); maintenance of nuclear YAP inhibits Runx2 initiation of osteogenesis. Injection of cytochalasin into the tibial marrow space of live mice results in abundant bone formation within the space of 1 week. In sum, increased intranuclear actin forces MSC into osteogenic lineage through controlling Runx2 activity; this process may be useful for clinical objectives of forming bone.
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Affiliation(s)
- Buer Sen
- Department of Medicine, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Zhihui Xie
- Department of Medicine, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Gunes Uzer
- Department of Medicine, University of North Carolina, Chapel Hill, North Carolina, USA
| | - William R Thompson
- Department of Physical Therapy, University of Indiana-Purdue, Indianapolis, Indiana
| | - Maya Styner
- Department of Medicine, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Xin Wu
- Department of Medicine, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Janet Rubin
- Department of Medicine, University of North Carolina, Chapel Hill, North Carolina, USA
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18
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Actin, actin-binding proteins, and actin-related proteins in the nucleus. Histochem Cell Biol 2016; 145:373-88. [PMID: 26847179 DOI: 10.1007/s00418-015-1400-9] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/21/2015] [Indexed: 10/25/2022]
Abstract
Extensive research in the past decade has significantly broadened our view about the role actin plays in the life of the cell and added novel aspects to actin research. One of these new aspects is the discovery of the existence of nuclear actin which became evident only recently. Nuclear activities including transcriptional activation in the case of all three RNA polymerases, editing and nuclear export of mRNAs, and chromatin remodeling all depend on actin. It also became clear that there is a fine-tuned equilibrium between cytoplasmic and nuclear actin pools and that this balance is ensured by an export-import system dedicated to actin. After over half a century of research on conventional actin and its organizing partners in the cytoplasm, it was also an unexpected finding that the nucleus contains more than 30 actin-binding proteins and new classes of actin-related proteins which are not able to form filaments but had evolved nuclear-specific functions. The actin-binding and actin-related proteins in the nucleus have been linked to RNA transcription and processing, nuclear transport, and chromatin remodeling. In this paper, we attempt to provide an overview of the wide range of information that is now available about actin, actin-binding, and actin-related proteins in the nucleus.
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Abstract
Contrary to cytoplasmic actin structures, the biological functions of nuclear actin filaments remain largely enigmatic. Recent progress in the field, however, has determined nuclear actin structures in somatic cells either under steady state conditions or in response to extracellular signaling cues. These actin structures differ in size and shape as well as in their temporal appearance and dynamics. Thus, a picture emerges that suggests that mammalian cells may have different pathways and mechanisms to assemble nuclear actin filaments. Apart from serum- or LPA-triggered nuclear actin polymerization, integrin activation by extracellular matrix interaction was recently implicated in nuclear actin polymerization through the linker of nucleoskeleton and cytoskeleton (LINC) complex. Some of these extracellular cues known so far appear to converge at the level of nuclear formin activity and subsequent regulation of myocardin-related transcription factors. Nevertheless, as the precise signaling events are as yet unknown, the regulation of nuclear actin polymerization may be of significant importance for different cellular functions as well as disease conditions caused by altered nuclear dynamics and architecture.
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20
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Plessner M, Melak M, Chinchilla P, Baarlink C, Grosse R. Nuclear F-actin formation and reorganization upon cell spreading. J Biol Chem 2015; 290:11209-16. [PMID: 25759381 DOI: 10.1074/jbc.m114.627166] [Citation(s) in RCA: 180] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Indexed: 12/30/2022] Open
Abstract
We recently discovered signal-regulated nuclear actin network assembly. However, in contrast to cytoplasmic actin regulation, polymeric nuclear actin structures and functions remain only poorly understood. Here we describe a novel molecular tool to visualize real-time nuclear actin dynamics by targeting the Actin-Chromobody-TagGFP to the nucleus, thus establishing a nuclear Actin-Chromobody. Interestingly, we observe nuclear actin polymerization into dynamic filaments upon cell spreading and fibronectin stimulation, both of which appear to be triggered by integrin signaling. Furthermore, we show that nucleoskeletal proteins such as the LINC (linker of nucleoskeleton and cytoskeleton) complex and components of the nuclear lamina couple cell spreading or integrin activation by fibronectin to nuclear actin polymerization. Spreading-induced nuclear actin polymerization results in serum response factor (SRF)-mediated transcription through nuclear retention of myocardin-related transcription factor A (MRTF-A). Our results reveal a signaling pathway, which links integrin activation by extracellular matrix interaction to nuclear actin polymerization through the LINC complex, and therefore suggest a role for nuclear actin polymerization in the context of cellular adhesion and mechanosensing.
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Affiliation(s)
- Matthias Plessner
- From the Institute of Pharmacology, Biochemical-Pharmacological Center (BPC), University of Marburg, Karl-von-Frisch-Strasse 1, 35043 Marburg, Germany
| | - Michael Melak
- From the Institute of Pharmacology, Biochemical-Pharmacological Center (BPC), University of Marburg, Karl-von-Frisch-Strasse 1, 35043 Marburg, Germany
| | - Pilar Chinchilla
- From the Institute of Pharmacology, Biochemical-Pharmacological Center (BPC), University of Marburg, Karl-von-Frisch-Strasse 1, 35043 Marburg, Germany
| | - Christian Baarlink
- From the Institute of Pharmacology, Biochemical-Pharmacological Center (BPC), University of Marburg, Karl-von-Frisch-Strasse 1, 35043 Marburg, Germany
| | - Robert Grosse
- From the Institute of Pharmacology, Biochemical-Pharmacological Center (BPC), University of Marburg, Karl-von-Frisch-Strasse 1, 35043 Marburg, Germany
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21
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Navarro-Lérida I, Pellinen T, Sanchez SA, Guadamillas MC, Wang Y, Mirtti T, Calvo E, Del Pozo MA. Rac1 nucleocytoplasmic shuttling drives nuclear shape changes and tumor invasion. Dev Cell 2015; 32:318-34. [PMID: 25640224 DOI: 10.1016/j.devcel.2014.12.019] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2013] [Revised: 08/06/2014] [Accepted: 12/19/2014] [Indexed: 11/26/2022]
Abstract
Nuclear membrane microdomains are proposed to act as platforms for regulation of nuclear function, but little is known about the mechanisms controlling their formation. Organization of the plasma membrane is regulated by actin polymerization, and the existence of an actin pool in the nucleus suggests that a similar mechanism might operate here. We show that nuclear membrane organization and morphology are regulated by the nuclear level of active Rac1 through actin polymerization-dependent mechanisms. Rac1 nuclear export is mediated by two internal nuclear export signals and through its interaction with nucleophosmin-1 (B23), which acts as a Rac1 chaperone inside the nucleus. Rac1 nuclear accumulation alters the balance between cytosolic Rac1 and Rho, increasing RhoA signaling in the cytoplasm and promoting a highly invasive phenotype. Nuclear Rac1 shuttling is a finely tuned mechanism for controlling nuclear shape and organization and cell invasiveness.
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Affiliation(s)
- Inmaculada Navarro-Lérida
- Integrin Signaling Laboratory, Department of Vascular Biology and Inflammation, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Melchor Fernández Almagro 3, 28029 Madrid, Spain
| | - Teijo Pellinen
- Integrin Signaling Laboratory, Department of Vascular Biology and Inflammation, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Melchor Fernández Almagro 3, 28029 Madrid, Spain; Institute for Molecular Medicine Finland (FIMM), University of Helsinki, Tukholmankatu 8, P.O. Box 20, 00014 Helsinki, Finland
| | - Susana A Sanchez
- Microscopy and Dynamic Imaging Unit, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Melchor Fernández Almagro 3, 28029 Madrid, Spain; Facultad de Ciencias Químicas, Universidad de Concepción, 4070371 Concepción, Chile
| | - Marta C Guadamillas
- Integrin Signaling Laboratory, Department of Vascular Biology and Inflammation, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Melchor Fernández Almagro 3, 28029 Madrid, Spain
| | - Yinhai Wang
- Institute for Molecular Medicine Finland (FIMM), University of Helsinki, Tukholmankatu 8, P.O. Box 20, 00014 Helsinki, Finland
| | - Tuomas Mirtti
- Institute for Molecular Medicine Finland (FIMM), University of Helsinki, Tukholmankatu 8, P.O. Box 20, 00014 Helsinki, Finland; HUSLAB, Department of Pathology, Haartman Institute, Helsinki University Central Hospital, Haartmaninkatu 3 C, P.O. Box 400, 00029 HUS Helsinki, Finland
| | - Enrique Calvo
- Proteomics Unit, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Melchor Fernández Almagro 3, 28029 Madrid, Spain
| | - Miguel A Del Pozo
- Integrin Signaling Laboratory, Department of Vascular Biology and Inflammation, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Melchor Fernández Almagro 3, 28029 Madrid, Spain.
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22
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Mallol A, Santaló J, Ibáñez E. Psammaplin a improves development and quality of somatic cell nuclear transfer mouse embryos. Cell Reprogram 2014; 16:392-406. [PMID: 25068567 DOI: 10.1089/cell.2014.0012] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Faulty reprogramming of the donor somatic nucleus to a totipotent embryonic state by the recipient oocyte is a major obstacle for cloning success. Accordingly, treatment of cloned embryos with epigenetic modifiers, such as histone deacetylase inhibitors (HDACi), enhances cloning efficiency. The purpose of our study was to further explore the potential effect of valproic acid (VPA), used in previous studies, and to investigate the effect of psammaplin A (PsA), a novel HDACi, on the development and quality of cloned mouse embryos. To this aim, cloned embryos were treated with 5, 10, and 20 μM PsA or 2 and 4 mM VPA for 8-9 h (before and during activation) or 16 h or 24 h (during and after activation), and their in vitro developmental potential and blastocyst quality were evaluated. Treatments with 10 μM PsA and 2 mM VPA for 16 h were selected as the most optimal, showing higher blastocyst rates and quality. These treatments had no significant effects on the expression of Nanog, Oct4, and Cdx2 or on global histone and DNA methylation levels at the blastocyst stage, but both increased global levels of histone acetylation at early developmental stages. This was correlated with a two-fold (for VPA) and four-fold (for PsA) increase in full-term development, and a 11.5-fold increase when PsA was combined with the use of latrunculin A instead of cytochalasin B. In conclusion, PsA improves mouse cloning efficiency to a higher extent than VPA.
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Affiliation(s)
- Anna Mallol
- Departament de Biologia Cel·lular, Fisiologia i Immunologia, Facultat de Biociències, Universitat Autònoma de Barcelona , 08193, Bellaterra, Spain
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