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Fernandez MK, Sinha M, Zidan M, Renz M. Nuclear actin filaments - a historical perspective. Nucleus 2024; 15:2320656. [PMID: 38384139 PMCID: PMC10885181 DOI: 10.1080/19491034.2024.2320656] [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: 11/22/2023] [Accepted: 02/14/2024] [Indexed: 02/23/2024] Open
Abstract
The view on nuclear filaments formed by non-skeletal β-actin has significantly changed over the decades. Initially, filamentous actin was observed in amphibian oocyte nuclei and only under specific cell stress conditions in mammalian cell nuclei. Improved labeling and imaging technologies have permitted insights into a transient but microscopically apparent filament network that is relevant for chromatin organization, biomechanics of the mammalian cell nucleus, gene expression, and DNA damage repair. Here, we will provide a historical perspective on the developing insight into nuclear actin filaments.
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Affiliation(s)
| | - Molika Sinha
- Gynecologic Oncology Division, School of Medicine Stanford University, Palo Alto, CA, USA
| | - Mia Zidan
- Gynecologic Oncology Division, School of Medicine Stanford University, Palo Alto, CA, USA
| | - Malte Renz
- Gynecologic Oncology Division, School of Medicine Stanford University, Palo Alto, CA, USA
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2
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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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Regulation of nuclear actin levels and MRTF/SRF target gene expression during PC6.3 cell differentiation. Exp Cell Res 2022; 420:113356. [PMID: 36122768 DOI: 10.1016/j.yexcr.2022.113356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Revised: 08/25/2022] [Accepted: 09/11/2022] [Indexed: 11/20/2022]
Abstract
Actin has important functions in both cytoplasm and nucleus of the cell, with active nuclear transport mechanisms maintaining the cellular actin balance. Nuclear actin levels are subject to regulation during many cellular processes from cell differentiation to cancer. Here we show that nuclear actin levels increase upon differentiation of PC6.3 cells towards neuron-like cells. Photobleaching experiments demonstrate that this increase is due to decreased nuclear export of actin during cell differentiation. Increased nuclear actin levels lead to decreased nuclear localization of MRTF-A, a well-established transcription cofactor of SRF. In line with MRTF-A localization, transcriptomics analysis reveals that MRTF/SRF target gene expression is first transiently activated, but then substantially downregulated during PC6.3 cell differentiation. This study therefore describes a novel cellular context, where regulation of nuclear actin is utilized to tune MRTF/SRF target gene expression during cell differentiation.
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Abstract
The presence of actin in the nucleus has been a matter of debate for many years. In recent years many important roles of actin in the nucleus (transcriptional regulation, chromatin remodeling, DNA repair, cell division, maintenance of nuclear architecture) have been identified, and the precise control of nuclear actin levels has been demonstrated. The vital importance of the actin driven processes in the cell make it highly likely that dysregulation of nuclear actin dynamics and structure can be linked to tumor induction and -progression. In this chapter I summarize our current knowledge about nuclear actin in the cancer context.
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Nuclear actin dynamics in gene expression and genome organization. Semin Cell Dev Biol 2020; 102:105-112. [DOI: 10.1016/j.semcdb.2019.10.012] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 08/28/2019] [Accepted: 10/24/2019] [Indexed: 11/19/2022]
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6
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Kashina AS. Regulation of actin isoforms in cellular and developmental processes. Semin Cell Dev Biol 2020; 102:113-121. [PMID: 32001148 DOI: 10.1016/j.semcdb.2019.12.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Revised: 12/02/2019] [Accepted: 12/02/2019] [Indexed: 12/18/2022]
Abstract
Actin is one of the most abundant and essential intracellular proteins that mediates nearly every form of cellular movement and underlies such key processes as embryogenesis, tissue integrity, cell division and contractility of all types of muscle and non-muscle cells. In mammals, actin is represented by six isoforms, which are encoded by different genes but produce proteins that are 95-99 % identical to each other. The six actin genes have vastly different functions in vivo, and the small amino acid differences between the proteins they encode are rigorously maintained through evolution, but the underlying differences behind this distinction, as well as the importance of specific amino acid sequences for each actin isoform, are not well understood. This review summarizes different levels of actin isoform-specific regulation in cellular and developmental processes, starting with the nuclear actin's role in transcription, and covering the gene-level, mRNA-level, and protein-level regulation, with a special focus on mammalian actins in non-muscle cells.
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Affiliation(s)
- Anna S Kashina
- University of Pennsylvania, Philadelphia, PA, 19104, United States.
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Sidorenko E, Vartiainen MK. Nucleoskeletal regulation of transcription: Actin on MRTF. Exp Biol Med (Maywood) 2019; 244:1372-1381. [PMID: 31142145 DOI: 10.1177/1535370219854669] [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: 01/23/2023] Open
Abstract
Myocardin-related transcription factor A (MRTF-A) and serum response factor (SRF) form an essential transcriptional complex that regulates the expression of many cytoskeletal genes in response to dynamic changes in the actin cytoskeleton. The nucleoskeleton, a “dynamic network of networks,” consists of numerous proteins that contribute to nuclear shape and to its various functions, including gene expression. In this review, we will discuss recent work that has identified many nucleoskeletal proteins, such as nuclear lamina and lamina-associated proteins, nuclear actin, and the linker of the cytoskeleton and nucleoskeleton complex as important regulators of MRTF-A/SRF transcriptional activity, especially in the context of mechanical control of transcription. Impact statement Regulation of gene expression is a fundamental cellular process that ensures the appropriate response of a cell to its surroundings. Alongside biochemical signals, mechanical cues, such as substrate rigidity, have been recognized as key regulators of gene expression. Nucleoskeletal components play an important role in mechanoresponsive transcription, particularly in controlling the activity of MRTF-A/SRF transcription factors. This ensures that the cell can balance the internal and external mechanical forces by fine-tuning the expression of cytoskeletal genes.
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Affiliation(s)
- Ekaterina Sidorenko
- Institute of Biotechnology, Helsinki Institute of Life Science, University of Helsinki, Helsinki 00014, Finland
| | - Maria K Vartiainen
- Institute of Biotechnology, Helsinki Institute of Life Science, University of Helsinki, Helsinki 00014, Finland
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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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Wang D, Liu H, Ren C, Wang L. High Expression of ABRACL Is Associated with Tumorigenesis and Affects Clinical Outcome in Gastric Cancer. Genet Test Mol Biomarkers 2019; 23:91-97. [PMID: 30676103 DOI: 10.1089/gtmb.2018.0195] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND The ABRA C-terminal like (ABRACL) protein belongs to a novel family of low-molecular weight proteins that increase actin dynamics and cell motility. It is involved in various diseases including cancer; however, its role in gastric cancer is unclear. In this study, the expression of ABRACL in gastric cancer and its relationships with patients' clinicopathological features and survival are examined. METHODS Sample expression profiles were downloaded from the Gene Expression Omnibus database and the Cancer Genome Atlas. ABRACL expression at the protein level in normal gastric and gastric cancer tissues was compared by using immunohistochemistry staining data provided by the Human Protein Atlas. Correlations between ABRACL expression and clinicopathological features are analyzed by chi-square tests. Patient survival was evaluated by Kaplan-Meier analysis. RESULTS ABRACL expression is upregulated in gastric cancer tissues than in normal tissues. High ABRACL levels indicated a poor prognosis. ABRACL expression (low ABRACL, n = 96; high ABRACL, n = 96) in gastric cancer tissues (primary data from GSE15459) is significantly correlated with poor overall survival (χ2 = 4.078, p = 0.043; log-rank test). ABRACL protein levels (low ABRACL, n = 172, high ABRACL, n = 171) in gastric cancer tissues (primary data from www.kmplot.com ) are significantly correlated with poor overall survival (χ2 = 4.305, p = 0.038, log-rank test). CONCLUSIONS Our results indicate that ABRACL is highly expressed in gastric cancer and is a potential prognostic marker and therapeutic target for this disease.
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Affiliation(s)
- Dazhi Wang
- 1 Pharmacy Department, Qingdao Municipal Hospital, Qingdao, China.,2 Cheeloo College of Medicine, Shandong University, Jinan, China
| | - HuaQiang Liu
- 1 Pharmacy Department, Qingdao Municipal Hospital, Qingdao, China
| | - Chunling Ren
- 3 Pharmacy Department, Qingdao Women and Children's Hospital, School of Medicine, Qingdao University, Qingdao, China
| | - Lanying Wang
- 1 Pharmacy Department, Qingdao Municipal Hospital, Qingdao, China
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Klages-Mundt NL, Kumar A, Zhang Y, Kapoor P, Shen X. The Nature of Actin-Family Proteins in Chromatin-Modifying Complexes. Front Genet 2018; 9:398. [PMID: 30319687 PMCID: PMC6167448 DOI: 10.3389/fgene.2018.00398] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 08/31/2018] [Indexed: 01/25/2023] Open
Abstract
Actin is not only one of the most abundant proteins in eukaryotic cells, but also one of the most versatile. In addition to its familiar involvement in enabling contraction and establishing cellular motility and scaffolding in the cytosol, actin has well-documented roles in a variety of processes within the confines of the nucleus, such as transcriptional regulation and DNA repair. Interestingly, monomeric actin as well as actin-related proteins (Arps) are found as stoichiometric subunits of a variety of chromatin remodeling complexes and histone acetyltransferases, raising the question of precisely what roles they serve in these contexts. Actin and Arps are present in unique combinations in chromatin modifiers, helping to establish structural integrity of the complex and enabling a wide range of functions, such as recruiting the complex to nucleosomes to facilitate chromatin remodeling and promoting ATPase activity of the catalytic subunit. Actin and Arps are also thought to help modulate chromatin dynamics and maintain higher-order chromatin structure. Moreover, the presence of actin and Arps in several chromatin modifiers is necessary for promoting genomic integrity and an effective DNA damage response. In this review, we discuss the involvement of actin and Arps in these nuclear complexes that control chromatin remodeling and histone modifications, while also considering avenues for future study to further shed light on their functional importance.
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Affiliation(s)
- Naeh L Klages-Mundt
- Science Park Research Division, Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Houston, TX, United States.,Program in Genetics & Epigenetics, The University of Texas MD Anderson Cancer Center, UTHealth Graduate School of Biomedical Sciences, Houston, TX, United States
| | - Ashok Kumar
- Department of Cellular and Molecular Biology, The University of Texas Health Science Center at Tyler, Tyler, TX, United States
| | - Yuexuan Zhang
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Prabodh Kapoor
- Department of Cellular and Molecular Biology, The University of Texas Health Science Center at Tyler, Tyler, TX, United States
| | - Xuetong Shen
- Science Park Research Division, Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Houston, TX, United States.,Program in Genetics & Epigenetics, The University of Texas MD Anderson Cancer Center, UTHealth Graduate School of Biomedical Sciences, Houston, TX, United States
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11
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Abstract
Although most people still associate actin mainly with the cytoskeleton, several lines of evidence, with the earliest studies dating back to decades ago, have emphasized the importance of actin also inside the cell nucleus. Actin has been linked to many gene expression processes from gene activation to chromatin remodeling, but also to maintenance of genomic integrity and intranuclear movement of chromosomes and chromosomal loci. Recent advances in visualizing different forms and dynamic properties of nuclear actin have clearly advanced our understanding of the basic concepts by which actin operates in the nucleus. In this chapter we address the different breakthroughs in nuclear actin studies, as well as discuss the regulation nuclear actin and the importance of nuclear actin dynamics in relation to its different nuclear functions. Our aim is to highlight the fact that actin should be considered as an essential component of the cell nucleus, and its nuclear actions should be taken into account also in experiments on cytoplasmic actin networks.
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Affiliation(s)
- Tiina Viita
- Program in Cell and Molecular Biology, Institute of Biotechnology, University of Helsinki, 56, Helsinki, Finland
| | - Maria K Vartiainen
- Program in Cell and Molecular Biology, Institute of Biotechnology, University of Helsinki, 56, Helsinki, Finland.
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12
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Mu J, Zhang Y, Hu Y, Hu X, Zhou Y, Zhao H, Pei R, Wu C, Chen J, Zhao H, Yang K, van Oers MM, Chen X, Wang Y. Autographa californica Multiple Nucleopolyhedrovirus Ac34 Protein Retains Cellular Actin-Related Protein 2/3 Complex in the Nucleus by Subversion of CRM1-Dependent Nuclear Export. PLoS Pathog 2016; 12:e1005994. [PMID: 27802336 PMCID: PMC5089780 DOI: 10.1371/journal.ppat.1005994] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Accepted: 10/12/2016] [Indexed: 12/21/2022] Open
Abstract
Actin, nucleation-promoting factors (NPFs), and the actin-related protein 2/3 complex (Arp2/3) are key elements of the cellular actin polymerization machinery. With nuclear actin polymerization implicated in ever-expanding biological processes and the discovery of the nuclear import mechanisms of actin and NPFs, determining Arp2/3 nucleo-cytoplasmic shuttling mechanism is important for understanding the function of nuclear actin. A unique feature of alphabaculovirus infection of insect cells is the robust nuclear accumulation of Arp2/3, which induces actin polymerization in the nucleus to assist in virus replication. We found that Ac34, a viral late gene product encoded by the alphabaculovirus Autographa californica multiple nucleopolyhedrovirus (AcMNPV), is involved in Arp2/3 nuclear accumulation during virus infection. Further assays revealed that the subcellular distribution of Arp2/3 under steady-state conditions is controlled by chromosomal maintenance 1 (CRM1)-dependent nuclear export. Upon AcMNPV infection, Ac34 inhibits CRM1 pathway and leads to Arp2/3 retention in the nucleus.
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Affiliation(s)
- Jingfang Mu
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Yongli Zhang
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Yangyang Hu
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Xue Hu
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
| | - Yuan Zhou
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
| | - He Zhao
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
| | - Rongjuan Pei
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
| | - Chunchen Wu
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
| | - Jizheng Chen
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
| | - Han Zhao
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Kai Yang
- State Key Laboratory of Biocontrol, Sun Yat-sen University, Guangzhou, China
| | | | - Xinwen Chen
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
| | - Yun Wang
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
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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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Verboon JM, Sugumar B, Parkhurst SM. Wiskott-Aldrich syndrome proteins in the nucleus: aWASH with possibilities. Nucleus 2016; 6:349-59. [PMID: 26305109 PMCID: PMC4915506 DOI: 10.1080/19491034.2015.1086051] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Actin and proteins that regulate its dynamics or interactions have well-established roles in the cytoplasm where they function as key components of the cytoskeleton to control diverse processes, including cellular infrastructure, cellular motility, cell signaling, and vesicle transport. Recent work has also uncovered roles for actin and its regulatory proteins in the nucleus, primarily in mechanisms governing gene expression. The Wiskott Aldrich Syndrome (WAS) family of proteins, comprising the WASP/N-WASP, SCAR/WAVE, WHAMM/JMY/WHAMY, and WASH subfamilies, function in the cytoplasm where they activate the Arp2/3 complex to form branched actin filaments. WAS proteins are present in the nucleus and have been implicated as transcriptional regulators. We found that Drosophila Wash, in addition to transcriptional effects, is involved in global nuclear architecture. Here we summarize the regulation and function of nuclear WAS proteins, and highlight how our work with Wash expands the possibilities for the functions of these proteins in the nucleus.
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Affiliation(s)
- Jeffrey M Verboon
- a Division of Basic Sciences; Fred Hutchinson Cancer Research Center ; Seattle , WA USA
| | - Bina Sugumar
- a Division of Basic Sciences; Fred Hutchinson Cancer Research Center ; Seattle , WA USA
| | - Susan M Parkhurst
- a Division of Basic Sciences; Fred Hutchinson Cancer Research Center ; Seattle , WA USA
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HSPC280, a winged helix protein expressed in the subventricular zone of the developing ganglionic eminences, inhibits neuronal differentiation. Histochem Cell Biol 2015; 145:175-84. [PMID: 26537243 DOI: 10.1007/s00418-015-1380-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/21/2015] [Indexed: 12/27/2022]
Abstract
Winged helix proteins have critical roles in a variety of developmental processes. During a screening for genes expressed in the developing forebrain, we identified HSPC280, a non-typical winged helix protein, which shares similarity with a protein-protein interaction domain found in the proteins of the actin-binding Rho-activating protein family. In this work, we analyzed HSPC280 expression during mouse development as well as during neuronal differentiation of mouse Neuro2a cells. HSPC280 expression is tightly regulated; during mouse development, it was detected predominantly in the ganglionic eminences of the ventral telencephalon, from their appearance at E11.5 to P0, with the highest levels between E13.5 and E15.5, a period that correlates with the peak of neurogenesis in these structures. Comparative expression analysis of HSPC280 with Dlx2, cyclinD2 and Lhx6 revealed that, within the ganglionic eminences, HSPC280 was restricted in the proliferating cell population of the subventricular zone, in a pattern similar to that of cyclinD2. Finally, we showed that HSPC280 is a nuclear protein which, when overexpressed in Neuro2a cells, it inhibited neuronal differentiation in vitro, suggesting its involvement in the mechanisms controlling neural progenitor cells proliferation.
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16
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Hendzel MJ. The F-act's of nuclear actin. Curr Opin Cell Biol 2014; 28:84-9. [DOI: 10.1016/j.ceb.2014.04.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2014] [Revised: 03/24/2014] [Accepted: 04/11/2014] [Indexed: 10/25/2022]
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