1
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Coulombe PA, Pineda CM, Jacob JT, Nair RR. Nuclear roles for non-lamin intermediate filament proteins. Curr Opin Cell Biol 2024; 86:102303. [PMID: 38113712 PMCID: PMC11056187 DOI: 10.1016/j.ceb.2023.102303] [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: 09/27/2023] [Revised: 11/21/2023] [Accepted: 11/26/2023] [Indexed: 12/21/2023]
Abstract
The nuclear-localized lamins have long been thought to be the only intermediate filaments (IFs) with an impact on the architecture, properties, and functions of the nucleus. Recent studies, however, uncovered significant roles for IFs other than lamins (here referred to as "non-lamin IFs") in regulating key properties of the nucleus in various cell types and biological settings. In the cytoplasm, IFs often occur in the perinuclear space where they contribute to local stiffness and impact the shape and/or the integrity of the nucleus, particularly in cells under stress. In addition, selective non-lamin IF proteins can occur inside the nucleus where they partake in fundamental processes including nuclear architecture and chromatin organization, regulation of gene expression, cell cycle progression, and the repair of DNA damage. This text reviews the evidence supporting a role for non-lamin IF proteins in regulating various properties of the nucleus and highlights opportunities for further study.
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Affiliation(s)
- Pierre A Coulombe
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI 48109, USA; Department of Dermatology, University of Michigan, Ann Arbor, MI 48109, USA; Rogel Cancer Center, University of Michigan, Ann Arbor, MI 48109, USA.
| | - Christopher M Pineda
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI 48109, USA; Program in Cellular and Molecular Biology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Justin T Jacob
- Public Health Laboratory Division, District of Columbia Department of Forensic Sciences, Washington, DC 20024, USA
| | - Raji R Nair
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
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2
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Stenvall CGA, Nyström JH, Butler-Hallissey C, Jansson T, Heikkilä TRH, Adam SA, Foisner R, Goldman RD, Ridge KM, Toivola DM. Cytoplasmic keratins couple with and maintain nuclear envelope integrity in colonic epithelial cells. Mol Biol Cell 2022; 33:ar121. [PMID: 36001365 PMCID: PMC9634972 DOI: 10.1091/mbc.e20-06-0387] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Keratin intermediate filaments convey mechanical stability and protection against stress to epithelial cells. Keratins are essential for colon health, as seen in keratin 8 knockout (K8-/-) mice exhibiting a colitis phenotype. We hypothesized that keratins support the nuclear envelope and lamina in colonocytes. K8-/- colonocytes in vivo exhibit significantly decreased levels of lamins A/C, B1, and B2 in a colon-specific and cell-intrinsic manner. CRISPR/Cas9- or siRNA-mediated K8 knockdown in Caco-2 cells similarly decreased lamin levels, which recovered after reexpression of K8 following siRNA treatment. Nuclear area was not decreased, and roundness was only marginally increased in cells without K8. Down-regulation of K8 in adult K8flox/flox;Villin-CreERt2 mice following tamoxifen administration significantly decreased lamin levels at day 4 when K8 levels had reduced to 40%. K8 loss also led to reduced levels of plectin, LINC complex, and lamin-associated proteins. While keratins were not seen in the nucleoplasm without or with leptomycin B treatment, keratins were found intimately located at the nuclear envelope and complexed with SUN2 and lamin A. Furthermore, K8 loss in Caco-2 cells compromised nuclear membrane integrity basally and after shear stress. In conclusion, colonocyte K8 helps maintain nuclear envelope and lamina composition and contributes to nuclear integrity.
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Affiliation(s)
| | - Joel H. Nyström
- Cell Biology, Biosciences, Faculty of Science and Engineering, Åbo Akademi University
| | - Ciarán Butler-Hallissey
- Cell Biology, Biosciences, Faculty of Science and Engineering, Åbo Akademi University,Turku Bioscience Centre, University of Turku, and Åbo Akademi University, and,Aix Marseille Université, CNRS, INP UMR7051, NeuroCyto, 13005 Marseille, France
| | - Theresia Jansson
- Cell Biology, Biosciences, Faculty of Science and Engineering, Åbo Akademi University
| | - Taina R. H. Heikkilä
- Cell Biology, Biosciences, Faculty of Science and Engineering, Åbo Akademi University
| | | | - Roland Foisner
- Max Perutz Labs, Medical University of Vienna, Vienna Biocenter Campus, 1030 Vienna, Austria
| | | | - Karen M. Ridge
- Department of Cell and Developmental Biology and,Pulmonary and Critical Care Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611
| | - Diana M. Toivola
- Cell Biology, Biosciences, Faculty of Science and Engineering, Åbo Akademi University,InFLAMES Research Flagship Center, Åbo Akademi University, 20500 Turku, Finland,Turku Center for Disease Modeling, University of Turku, 20520 Turku, Finland,*Address correspondence to: Diana M. Toivola ()
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3
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Baraks G, Tseng R, Pan CH, Kasliwal S, Leiton CV, Shroyer KR, Escobar-Hoyos LF. Dissecting the Oncogenic Roles of Keratin 17 in the Hallmarks of Cancer. Cancer Res 2021; 82:1159-1166. [PMID: 34921015 PMCID: PMC9016724 DOI: 10.1158/0008-5472.can-21-2522] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 11/08/2021] [Accepted: 12/14/2021] [Indexed: 11/16/2022]
Affiliation(s)
- Gabriella Baraks
- Undergraduate Program in Biomedical Engineering, Stony Brook University, Stony Brook, New York
- Department of Pathology, Renaissance School of Medicine, Stony Brook University, Stony Brook, New York
| | - Robert Tseng
- Department of Pathology, Renaissance School of Medicine, Stony Brook University, Stony Brook, New York
| | - Chun-Hao Pan
- Department of Pathology, Renaissance School of Medicine, Stony Brook University, Stony Brook, New York
- Molecular and Cellular Biology Graduate Program, Stony Brook University, New York
| | - Saumya Kasliwal
- Department of Pathology, Renaissance School of Medicine, Stony Brook University, Stony Brook, New York
| | - Cindy V. Leiton
- Department of Pathology, Renaissance School of Medicine, Stony Brook University, Stony Brook, New York
| | - Kenneth R. Shroyer
- Department of Pathology, Renaissance School of Medicine, Stony Brook University, Stony Brook, New York
- Corresponding Authors: Kenneth R. Shroyer, Pathology, Stony Brook University, 101 Nicolls Rd, Stony Brook, NY 11794. Phone: 631-444-3000; E-mail: Kenneth.; and Luisa F. Escobar-Hoyos, 15 York Street PO Box 208040, New Haven, CT 06513. Phone: 203-737-2003; E-mail:
| | - Luisa F. Escobar-Hoyos
- Department of Pathology, Renaissance School of Medicine, Stony Brook University, Stony Brook, New York
- Department of Therapeutic Radiology and Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut
- Corresponding Authors: Kenneth R. Shroyer, Pathology, Stony Brook University, 101 Nicolls Rd, Stony Brook, NY 11794. Phone: 631-444-3000; E-mail: Kenneth.; and Luisa F. Escobar-Hoyos, 15 York Street PO Box 208040, New Haven, CT 06513. Phone: 203-737-2003; E-mail:
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4
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Yu B, Kong D, Cheng C, Xiang D, Cao L, Liu Y, He Y. Assembly and recognition of keratins: A structural perspective. Semin Cell Dev Biol 2021; 128:80-89. [PMID: 34654627 DOI: 10.1016/j.semcdb.2021.09.018] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 09/22/2021] [Accepted: 09/29/2021] [Indexed: 12/21/2022]
Abstract
Keratins are one of the major components of cytoskeletal network and assemble into fibrous structures named intermediate filaments (IFs), which are important for maintaining the mechanical properties of cells and tissues. Over the past decades, evidence has shown that the functions of keratins go beyond providing mechanical support for cells, they interact with multiple cellular components and are widely involved in the pathways of cell proliferation, differentiation, motility and death. However, the structural details of keratins and IFs are largely missing and many questions remain regarding the mechanisms of keratin assembly and recognition. Here we briefly review the current structural models and assembly of keratins as well as the interactions of keratins with the binding partners, which may provide a structural view for understanding the mechanisms of keratins in the biological activities and the related diseases.
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Affiliation(s)
- Bowen Yu
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Department of Immunology, School of Basic Medical Sciences, Weifang Medical University, Weifang, China
| | - Dandan Kong
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Chen Cheng
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Dongxi Xiang
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Department of Biliary-Pancreatic Surgery, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Longxing Cao
- School of Life Science, Westlake University, Hangzhou, Zhejiang, China
| | - Yingbin Liu
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Department of Biliary-Pancreatic Surgery, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yongning He
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Department of Biliary-Pancreatic Surgery, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, China.
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5
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Maarof ND, Kumeta M, Yoshimura SH. Modulation of actin-binding and -bundling activities of MISP/Caprice by multiple phosphorylation. Biochem Biophys Res Commun 2021; 561:128-135. [PMID: 34023777 DOI: 10.1016/j.bbrc.2021.05.041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Accepted: 05/13/2021] [Indexed: 11/29/2022]
Abstract
The actin cytoskeleton plays critical roles in numerous cellular events and functions, and its spatiotemporal dynamics are maintained and regulated by several actin cofactor proteins. MISP/Caprice is a recently reported actin-bundling protein that is also involved in the progression of mitosis. In this study, we investigated how the actin-regulatory function of MISP is modulated by phosphorylation. A series of mutation studies demonstrated that phosphorylation of S394, S395, and S400 induced stress fiber formation in interphase cells. In vitro studies revealed that these phosphorylation events increased the actin-bundling activity but not the actin-binding activity of MISP. Moreover, actin-binding activity was suppressed by mitotic phosphorylation, including that at S376, S471, and S541. These results indicate that phosphorylation during interphase and mitosis differentially regulates the actin-binding and -bundling activities of MISP, in turn regulating the higher-order architecture of the actin cytoskeleton during cell cycle.
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Affiliation(s)
- Nur Diyana Maarof
- Graduate School of Biostudies, Kyoto University, Yoshida-konoe, Sakyo-ku, Kyoto, 606-8501, Japan
| | - Masahiro Kumeta
- Graduate School of Biostudies, Kyoto University, Yoshida-konoe, Sakyo-ku, Kyoto, 606-8501, Japan
| | - Shige H Yoshimura
- Graduate School of Biostudies, Kyoto University, Yoshida-konoe, Sakyo-ku, Kyoto, 606-8501, Japan.
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6
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Sjöqvist M, Antfolk D, Suarez-Rodriguez F, Sahlgren C. From structural resilience to cell specification - Intermediate filaments as regulators of cell fate. FASEB J 2020; 35:e21182. [PMID: 33205514 PMCID: PMC7839487 DOI: 10.1096/fj.202001627r] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 10/05/2020] [Accepted: 10/28/2020] [Indexed: 12/18/2022]
Abstract
During the last decades intermediate filaments (IFs) have emerged as important regulators of cellular signaling events, ascribing IFs with functions beyond the structural support they provide. The organ and developmental stage‐specific expression of IFs regulate cell differentiation within developing or remodeling tissues. Lack of IFs causes perturbed stem cell differentiation in vasculature, intestine, nervous system, and mammary gland, in transgenic mouse models. The aberrant cell fate decisions are caused by deregulation of different stem cell signaling pathways, such as Notch, Wnt, YAP/TAZ, and TGFβ. Mutations in genes coding for IFs cause an array of different diseases, many related to stem cell dysfunction, but the molecular mechanisms remain unresolved. Here, we provide a comprehensive overview of how IFs interact with and regulate the activity, localization and function of different signaling proteins in stem cells, and how the assembly state and PTM profile of IFs may affect these processes. Identifying when, where and how IFs and cell signaling congregate, will expand our understanding of IF‐linked stem cell dysfunction during development and disease.
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Affiliation(s)
- Marika Sjöqvist
- Faculty of Science and Engineering, Cell Biology, Åbo Akademi University, Turku, Finland.,Turku Bioscience, Åbo Akademi University and University of Turku, Turku, Finland
| | - Daniel Antfolk
- Faculty of Science and Engineering, Cell Biology, Åbo Akademi University, Turku, Finland.,Turku Bioscience, Åbo Akademi University and University of Turku, Turku, Finland
| | - Freddy Suarez-Rodriguez
- Faculty of Science and Engineering, Cell Biology, Åbo Akademi University, Turku, Finland.,Turku Bioscience, Åbo Akademi University and University of Turku, Turku, Finland
| | - Cecilia Sahlgren
- Faculty of Science and Engineering, Cell Biology, Åbo Akademi University, Turku, Finland.,Turku Bioscience, Åbo Akademi University and University of Turku, Turku, Finland.,Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, Netherlands
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7
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Jacob JT, Nair RR, Poll BG, Pineda CM, Hobbs RP, Matunis MJ, Coulombe PA. Keratin 17 regulates nuclear morphology and chromatin organization. J Cell Sci 2020; 133:jcs254094. [PMID: 33008845 PMCID: PMC7648610 DOI: 10.1242/jcs.254094] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Accepted: 09/18/2020] [Indexed: 12/14/2022] Open
Abstract
Keratin 17 (KRT17; K17), a non-lamin intermediate filament protein, was recently found to occur in the nucleus. We report here on K17-dependent differences in nuclear morphology, chromatin organization, and cell proliferation. Human tumor keratinocyte cell lines lacking K17 exhibit flatter nuclei relative to normal. Re-expression of wild-type K17, but not a mutant form lacking an intact nuclear localization signal (NLS), rescues nuclear morphology in KRT17-null cells. Analyses of primary cultures of skin keratinocytes from a mouse strain expressing K17 with a mutated NLS corroborated these findings. Proteomics screens identified K17-interacting nuclear proteins with known roles in gene expression, chromatin organization and RNA processing. Key histone modifications and LAP2β (an isoform encoded by TMPO) localization within the nucleus are altered in the absence of K17, correlating with decreased cell proliferation and suppression of GLI1 target genes. Nuclear K17 thus impacts nuclear morphology with an associated impact on chromatin organization, gene expression, and proliferation in epithelial cells.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Justin T Jacob
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Raji R Nair
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, USA
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Brian G Poll
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Christopher M Pineda
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Ryan P Hobbs
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Michael J Matunis
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, USA
- Department of Cell Biology, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Pierre A Coulombe
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, USA
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
- Department of Dermatology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
- Rogel Cancer Center, University of Michigan, Ann Arbor, MI 48109, USA
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8
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Zieman AG, Poll BG, Ma J, Coulombe PA. Altered keratinocyte differentiation is an early driver of keratin mutation-based palmoplantar keratoderma. Hum Mol Genet 2020; 28:2255-2270. [PMID: 31220272 DOI: 10.1093/hmg/ddz050] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Revised: 01/08/2019] [Accepted: 03/04/2019] [Indexed: 12/15/2022] Open
Abstract
The type I intermediate filament keratin 16 (KRT16 gene; K16 protein) is constitutively expressed in ectoderm-derived appendages and in palmar/plantar epidermis and is robustly induced when the epidermis experiences chemical, mechanical or environmental stress. Missense mutations at the KRT16 locus can cause pachyonychia congenita (PC, OMIM:167200) or focal non-epidermolytic palmoplantar keratoderma (FNEPPK, OMIM:613000), which each entail painful calluses on palmar and plantar skin. Krt16-null mice develop footpad lesions that mimic PC-associated PPK, providing an opportunity to decipher its pathophysiology, and develop therapies. We report on insight gained from a genome-wide analysis of gene expression in PPK-like lesions of Krt16-null mice. Comparison of this data set with publicly available microarray data of PPK lesions from individuals with PC revealed significant synergies in gene expression profiles. Keratin 9 (Krt9/K9), the most robustly expressed gene in differentiating volar keratinocytes, is markedly downregulated in Krt16-null paw skin, well-ahead of lesion onset, and is paralleled by pleiotropic defects in terminal differentiation. Effective prevention of PPK-like lesions in Krt16-null paw skin (via topical delivery of the Nrf2 inducer sulforaphane) involves the stimulation of Krt9 expression. These findings highlight a role for defective terminal differentiation and loss of Krt9/K9 expression as additional drivers of PC-associated PPK and highlight restoration of KRT9 expression as a worthy target for therapy. Further, we report on the novel observation that keratin 16 can localize to the nucleus of epithelial cells, implying a potential nuclear function that may be relevant to PC and FNEPPK.
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Affiliation(s)
- Abigail G Zieman
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA.,Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Brian G Poll
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA.,Department of Physiology, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Jingqun Ma
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Pierre A Coulombe
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA.,Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI, USA
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9
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Zhu S, Paydar M, Wang F, Li Y, Wang L, Barrette B, Bessho T, Kwok BH, Peng A. Kinesin Kif2C in regulation of DNA double strand break dynamics and repair. eLife 2020; 9:53402. [PMID: 31951198 PMCID: PMC7012618 DOI: 10.7554/elife.53402] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Accepted: 01/16/2020] [Indexed: 12/12/2022] Open
Abstract
DNA double strand breaks (DSBs) have detrimental effects on cell survival and genomic stability, and are related to cancer and other human diseases. In this study, we identified microtubule-depolymerizing kinesin Kif2C as a protein associated with DSB-mimicking DNA templates and known DSB repair proteins in Xenopus egg extracts and mammalian cells. The recruitment of Kif2C to DNA damage sites was dependent on both PARP and ATM activities. Kif2C knockdown or knockout led to accumulation of endogenous DNA damage, DNA damage hypersensitivity, and reduced DSB repair via both NHEJ and HR. Interestingly, Kif2C depletion, or inhibition of its microtubule depolymerase activity, reduced the mobility of DSBs, impaired the formation of DNA damage foci, and decreased the occurrence of foci fusion and resolution. Taken together, our study established Kif2C as a new player of the DNA damage response, and presented a new mechanism that governs DSB dynamics and repair.
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Affiliation(s)
- Songli Zhu
- Department of Oral Biology, College of Dentistry, University of Nebraska Medical Center, Omaha, United States
| | - Mohammadjavad Paydar
- Institute for Research in Immunology and Cancer (IRIC), Département de médecine, Université de Montréal, Montréal, Canada
| | - Feifei Wang
- Department of Oral Biology, College of Dentistry, University of Nebraska Medical Center, Omaha, United States.,Institute of Physical Science and Information Technology, Anhui University, Hefei, China
| | - Yanqiu Li
- Department of Oral Biology, College of Dentistry, University of Nebraska Medical Center, Omaha, United States
| | - Ling Wang
- Department of Oral Biology, College of Dentistry, University of Nebraska Medical Center, Omaha, United States
| | - Benoit Barrette
- Institute for Research in Immunology and Cancer (IRIC), Département de médecine, Université de Montréal, Montréal, Canada
| | - Tadayoshi Bessho
- Eppley Institute for Research in Cancer and Allied Diseases, Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, United States
| | - Benjamin H Kwok
- Institute for Research in Immunology and Cancer (IRIC), Département de médecine, Université de Montréal, Montréal, Canada
| | - Aimin Peng
- Department of Oral Biology, College of Dentistry, University of Nebraska Medical Center, Omaha, United States
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10
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Schwarzerová K, Bellinvia E, Martinek J, Sikorová L, Dostál V, Libusová L, Bokvaj P, Fischer L, Schmit AC, Nick P. Tubulin is actively exported from the nucleus through the Exportin1/CRM1 pathway. Sci Rep 2019; 9:5725. [PMID: 30952896 PMCID: PMC6451007 DOI: 10.1038/s41598-019-42056-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Accepted: 03/15/2019] [Indexed: 12/11/2022] Open
Abstract
Microtubules of all eukaryotic cells are formed by α- and β-tubulin heterodimers. In addition to the well known cytoplasmic tubulins, a subpopulation of tubulin can occur in the nucleus. So far, the potential function of nuclear tubulin has remained elusive. In this work, we show that α- and β-tubulins of various organisms contain multiple conserved nuclear export sequences, which are potential targets of the Exportin 1/CRM1 pathway. We demonstrate exemplarily that these NES motifs are sufficient to mediate export of GFP as model cargo and that this export can be inhibited by leptomycin B, an inhibitor of the Exportin 1/CRM1 pathway. Likewise, leptomycin B causes accumulation of GFP-tagged tubulin in interphase nuclei, in both plant and animal model cells. Our analysis of nuclear tubulin content supports the hypothesis that an important function of nuclear tubulin export is the exclusion of tubulin from interphase nuclei, after being trapped by nuclear envelope reassembly during telophase.
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Affiliation(s)
- K Schwarzerová
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Viničná 5, Prague, Czech Republic.
| | - E Bellinvia
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Viničná 5, Prague, Czech Republic
| | - J Martinek
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Viničná 5, Prague, Czech Republic
| | - L Sikorová
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Viničná 5, Prague, Czech Republic
| | - V Dostál
- Department of Cell Biology, Faculty of Science, Charles University, Prague, Viničná 7, Czech Republic
| | - L Libusová
- Department of Cell Biology, Faculty of Science, Charles University, Prague, Viničná 7, Czech Republic
| | - P Bokvaj
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Viničná 5, Prague, Czech Republic
| | - L Fischer
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Viničná 5, Prague, Czech Republic
| | - A C Schmit
- Institut de Biologie Moléculaire des Plantes, Centre National de La Recherche Scientifique, Université de Strasbourg, F67084, Strasbourg-cedex, France
| | - P Nick
- Molecular Cell Biology, Botanical Institute, Karlsruhe Institute of Technology (KIT), Fritz-Haber-Weg 4, 76131, Karlsruhe, Germany
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11
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Accurate and fiducial-marker-free correction for three-dimensional chromatic shift in biological fluorescence microscopy. Sci Rep 2018; 8:7583. [PMID: 29765093 PMCID: PMC5954143 DOI: 10.1038/s41598-018-25922-7] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Accepted: 05/02/2018] [Indexed: 11/09/2022] Open
Abstract
Correction of chromatic shift is necessary for precise registration of multicolor fluorescence images of biological specimens. New emerging technologies in fluorescence microscopy with increasing spatial resolution and penetration depth have prompted the need for more accurate methods to correct chromatic aberration. However, the amount of chromatic shift of the region of interest in biological samples often deviates from the theoretical prediction because of unknown dispersion in the biological samples. To measure and correct chromatic shift in biological samples, we developed a quadrisection phase correlation approach to computationally calculate translation, rotation, and magnification from reference images. Furthermore, to account for local chromatic shifts, images are split into smaller elements, for which the phase correlation between channels is measured individually and corrected accordingly. We implemented this method in an easy-to-use open-source software package, called Chromagnon, that is able to correct shifts with a 3D accuracy of approximately 15 nm. Applying this software, we quantified the level of uncertainty in chromatic shift correction, depending on the imaging modality used, and for different existing calibration methods, along with the proposed one. Finally, we provide guidelines to choose the optimal chromatic shift registration method for any given situation.
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12
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Cruz R, Pereira-Castro I, Almeida MT, Moreira A, Cabanes D, Sousa S. Epithelial Keratins Modulate cMet Expression and Signaling and Promote InlB-Mediated Listeria monocytogenes Infection of HeLa Cells. Front Cell Infect Microbiol 2018; 8:146. [PMID: 29868502 PMCID: PMC5960701 DOI: 10.3389/fcimb.2018.00146] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Accepted: 04/20/2018] [Indexed: 12/11/2022] Open
Abstract
The host cytoskeleton is a major target for bacterial pathogens during infection. In particular, pathogens usurp the actin cytoskeleton function to strongly adhere to the host cell surface, to induce plasma membrane remodeling allowing invasion and to spread from cell to cell and disseminate to the whole organism. Keratins are cytoskeletal proteins that are the major components of intermediate filaments in epithelial cells however, their role in bacterial infection has been disregarded. Here we investigate the role of the major epithelial keratins, keratins 8 and 18 (K8 and K18), in the cellular infection by Listeria monocytogenes. We found that K8 and K18 are required for successful InlB/cMet-dependent L. monocytogenes infection, but are dispensable for InlA/E-cadherin-mediated invasion. Both K8 and K18 accumulate at InlB-mediated internalization sites following actin recruitment and modulate actin dynamics at those sites. We also reveal the key role of K8 and K18 in HGF-induced signaling which occurs downstream the activation of cMet. Strikingly, we show here that K18, and at a less extent K8, controls the expression of cMet and other surface receptors such TfR and integrin β1, by promoting the stability of their corresponding transcripts. Together, our results reveal novel functions for major epithelial keratins in the modulation of actin dynamics at the bacterial entry sites and in the control of surface receptors mRNA stability and expression.
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Affiliation(s)
- Rui Cruz
- Group of Molecular Microbiology, Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,Group of Molecular Microbiology, Institute for Molecular and Cell Biology, Porto, Portugal.,Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Porto, Portugal
| | - Isabel Pereira-Castro
- Group of Molecular Microbiology, Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,Gene Regulation Group, Institute for Molecular and Cell Biology, Porto, Portugal
| | - Maria T Almeida
- Group of Molecular Microbiology, Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,Group of Molecular Microbiology, Institute for Molecular and Cell Biology, Porto, Portugal
| | - Alexandra Moreira
- Group of Molecular Microbiology, Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Porto, Portugal.,Gene Regulation Group, Institute for Molecular and Cell Biology, Porto, Portugal
| | - Didier Cabanes
- Group of Molecular Microbiology, Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,Group of Molecular Microbiology, Institute for Molecular and Cell Biology, Porto, Portugal
| | - Sandra Sousa
- Group of Molecular Microbiology, Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,Group of Molecular Microbiology, Institute for Molecular and Cell Biology, Porto, Portugal
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13
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Abstract
Previously thought to reside exclusively in the cytoplasm, the cytoskeletal protein keratin 17 (K17) has been recently identified inside the nucleus of tumor epithelial cells with a direct impact on cell proliferation and gene expression. We comment on fundamental questions raised by this new finding and the associated significance.
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Affiliation(s)
- Ryan P Hobbs
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Justin T Jacob
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Pierre A Coulombe
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, USA; Department of Biological Chemistry, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA; Department of Oncology, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA; Department of Dermatology, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA; The Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University, Baltimore, MD 21205, USA.
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14
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Clawson GA, Matters GL, Xin P, Imamura-Kawasawa Y, Du Z, Thiboutot DM, Helm KF, Neves RI, Abraham T. Macrophage-tumor cell fusions from peripheral blood of melanoma patients. PLoS One 2015; 10:e0134320. [PMID: 26267609 PMCID: PMC4534457 DOI: 10.1371/journal.pone.0134320] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Accepted: 06/30/2015] [Indexed: 12/13/2022] Open
Abstract
Background While the morbidity and mortality from cancer are largely attributable to its metastatic dissemination, the integral features of the cascade are not well understood. The widely accepted hypothesis is that the primary tumor microenvironment induces the epithelial-to-mesenchymal transition in cancer cells, facilitating their escape into the bloodstream, possibly accompanied by cancer stem cells. An alternative theory for metastasis involves fusion of macrophages with tumor cells (MTFs). Here we culture and characterize apparent MTFs from blood of melanoma patients. Methods We isolated enriched CTC populations from peripheral blood samples from melanoma patients, and cultured them. We interrogated these cultured cells for characteristic BRAF mutations, and used confocal microscopy for immunophenotyping, motility, DNA content and chromatin texture analyses, and then conducted xenograft studies using nude mice. Findings Morphologically, the cultured MTFs were generally large with many pseudopod extensions and lamellipodia. Ultrastructurally, the cultured MTFs appeared to be macrophages. They were rich in mitochondria and lysosomes, as well as apparent melanosomes. The cultured MTF populations were all heterogeneous with regard to DNA content, containing aneuploid and/or high-ploidy cells, and they typically showed large sheets (and/or clumps) of cytoplasmic chromatin. This cytoplasmic DNA was found within heterogeneously-sized autophagic vacuoles, which prominently contained chromatin and micronuclei. Cultured MTFs uniformly expressed pan-macrophage markers (CD14, CD68) and macrophage markers indicative of M2 polarization (CD163, CD204, CD206). They also expressed melanocyte-specific markers (ALCAM, MLANA), epithelial biomarkers (KRT, EpCAM), as well as the pro-carcinogenic cytokine MIF along with functionally related stem cell markers (CXCR4, CD44). MTF cultures from individual patients (5 of 8) contained melanoma-specific BRAF activating mutations. Chromatin texture analysis of deconvoluted images showed condensed DNA (DAPI-intense) regions similar to focal regions described in stem cell fusions. MTFs were readily apparent in vivo in all human melanomas examined, often exhibiting even higher DNA content than the cultured MTFs. When cultured MTFs were transplanted subcutaneously in nude mice, they disseminated and produced metastatic lesions at distant sites. Conclusions and Hypothesis Apparent MTFs are present in peripheral blood of patients with cutaneous melanomas, and they possess the ability to form metastatic lesions when transplanted into mice. We hypothesize that these MTFs arise at the periphery of primary tumors in vivo, that they readily enter the bloodstream and invade distant tissues, secreting cytokines (such as MIF) to prepare “niches” for colonization by metastasis initiating cells.
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Affiliation(s)
- Gary A. Clawson
- Department of Pathology and Gittlen Cancer Research Laboratories, Hershey Medical Center, Pennsylvania State University, Hershey, Pennsylvania, United States of America
- * E-mail:
| | - Gail L. Matters
- Department of Biochemistry & Molecular Biology, Hershey Medical Center, Pennsylvania State University, Hershey, Pennsylvania, United States of America
| | - Ping Xin
- Department of Pathology and Gittlen Cancer Research Laboratories, Hershey Medical Center, Pennsylvania State University, Hershey, Pennsylvania, United States of America
| | - Yuka Imamura-Kawasawa
- Department of Pharmacology and the Institute for Personalized Medicine, Hershey Medical Center, Pennsylvania State University, Hershey, Pennsylvania, United States of America
| | - Zhen Du
- Department of Pathology and Gittlen Cancer Research Laboratories, Hershey Medical Center, Pennsylvania State University, Hershey, Pennsylvania, United States of America
| | - Diane M. Thiboutot
- Department of Dermatology, Division of Health Science Research, Hershey Medical Center, Pennsylvania State University, Hershey, Pennsylvania, United States of America
| | - Klaus F. Helm
- Department of Dermatopathology, Hershey Medical Center, Pennsylvania State University, Hershey, Pennsylvania, United States of America
| | - Rogerio I. Neves
- Department of Surgery and the Melanoma Center, Hershey Medical Center, Pennsylvania State University, Hershey, Pennsylvania, United States of America
| | - Thomas Abraham
- Department of Neural and Behavioral Science and the Microscopy Imaging Facility, Hershey Medical Center, Pennsylvania State University, Hershey, Pennsylvania, United States of America
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15
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Hobbs RP, DePianto DJ, Jacob JT, Han MC, Chung BM, Batazzi AS, Poll BG, Guo Y, Han J, Ong S, Zheng W, Taube JM, Čiháková D, Wan F, Coulombe PA. Keratin-dependent regulation of Aire and gene expression in skin tumor keratinocytes. Nat Genet 2015; 47:933-8. [PMID: 26168014 PMCID: PMC4520766 DOI: 10.1038/ng.3355] [Citation(s) in RCA: 92] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Accepted: 06/19/2015] [Indexed: 12/20/2022]
Abstract
Expression of the intermediate filament protein keratin 17 (K17) is robustly upregulated in inflammatory skin diseases and in many tumors originating in stratified and pseudostratified epithelia. We report that autoimmune regulator (Aire), a transcriptional regulator, is inducibly expressed in human and mouse tumor keratinocytes in a K17-dependent manner and is required for timely onset of Gli2-induced skin tumorigenesis in mice. The induction of Aire mRNA in keratinocytes depends on a functional interaction between K17 and the heterogeneous nuclear ribonucleoprotein hnRNP K. Further, K17 colocalizes with Aire protein in the nucleus of tumor-prone keratinocytes, and each factor is bound to a specific promoter region featuring an NF-κB consensus sequence in a relevant subset of K17- and Aire-dependent proinflammatory genes. These findings provide radically new insight into keratin intermediate filament and Aire function, along with a molecular basis for the K17-dependent amplification of inflammatory and immune responses in diseased epithelia.
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Affiliation(s)
- Ryan P. Hobbs
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Daryle J. DePianto
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Justin T. Jacob
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Minerva C. Han
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Byung-Min Chung
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Adriana S. Batazzi
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Brian G. Poll
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Yajuan Guo
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Jingnan Han
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, USA
| | - SuFey Ong
- Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Wenxin Zheng
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Janis M. Taube
- Department of Pathology, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA
- Department of Dermatology, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Daniela Čiháková
- Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, USA
- Department of Pathology, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Fengyi Wan
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, USA
- Department of Oncology, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA
- The Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University, Baltimore MD 21205, USA
| | - Pierre A. Coulombe
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, USA
- Department of Dermatology, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA
- Department of Oncology, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA
- Department of Biological Chemistry, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA
- The Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University, Baltimore MD 21205, USA
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16
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Escobar-Hoyos LF, Shah R, Roa-Peña L, Vanner EA, Najafian N, Banach A, Nielsen E, Al-Khalil R, Akalin A, Talmage D, Shroyer KR. Keratin-17 Promotes p27KIP1 Nuclear Export and Degradation and Offers Potential Prognostic Utility. Cancer Res 2015; 75:3650-62. [PMID: 26109559 DOI: 10.1158/0008-5472.can-15-0293] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Accepted: 05/14/2015] [Indexed: 11/16/2022]
Abstract
Keratins that are overexpressed selectively in human carcinomas may offer diagnostic and prognostic utility. In this study, we show that high expression of keratin-17 (K17) predicts poor outcome in patients with cervical cancer, at early or late stages of disease, surpassing in accuracy either tumor staging or loss of p27(KIP1) as a negative prognostic marker in this setting. We investigated the mechanistic basis for the biologic impact of K17 through loss- and gain-of-function experiments in human cervix, breast, and pancreatic cancer cells. Specifically, we determined that K17 functions as an oncoprotein by regulating the subcellular localization and degradation of p27(KIP1). We found that K17 was released from intermediate filaments and translocated into the nucleus via a nuclear localization signal (NLS), specific among keratins, where it bound p27(KIP1) during G1 phase of the cell cycle. p27(KIP1) lacks a nuclear export signal (NES) and requires an adaptor for CRM1 binding for nuclear export. In K17, we defined and validated a leucine-rich NES that mediated CRM1 binding for export. Cervical cancer cells expressing K17 mutations in its NLS or NES signals exhibited an increase in levels of nuclear p27(KIP1), whereas cells expressing wild-type K17 exhibited a depletion in total endogenous p27(KIP1). In clinical specimens of cervical cancer, we confirmed that the expressions of K17 and p27(KIP1) were inversely correlated, both across tumors and within individual tumors. Overall, our findings establish that K17 functions specially among keratins as an oncoprotein by controlling the ability of p27(KIP1) to influence cervical cancer pathogenesis.
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Affiliation(s)
- Luisa F Escobar-Hoyos
- Department of Pharmacological Sciences, Stony Brook Medicine, Stony Brook, New York. Department of Pathology, Stony Brook Medicine, Stony Brook, New York. Department of Biology, Research Group Genetic Toxicology and Cytogenetics, Department of Natural Sciences and Education, Universidad del Cauca, Popayán, Cauca, Colombia
| | - Ruchi Shah
- Department of Pathology, Stony Brook Medicine, Stony Brook, New York
| | - Lucia Roa-Peña
- Department of Pathology, Stony Brook Medicine, Stony Brook, New York. Department of Pathology, School of Medicine, National University of Colombia, Bogotá, Cundinamarca, Colombia
| | | | - Nilofar Najafian
- Department of Pathology, Stony Brook Medicine, Stony Brook, New York
| | - Anna Banach
- Molecular and Cellular Biology, Stony Brook Medicine, Stony Brook, New York
| | - Erik Nielsen
- Department of Pathology, Stony Brook Medicine, Stony Brook, New York
| | - Ramsey Al-Khalil
- Department of Pathology, Stony Brook Medicine, Stony Brook, New York
| | - Ali Akalin
- Department of Pathology, University of Massachusetts Memorial Medical Center, Worcester, Massachusetts
| | - David Talmage
- Department of Pharmacological Sciences, Stony Brook Medicine, Stony Brook, New York
| | - Kenneth R Shroyer
- Department of Pathology, Stony Brook Medicine, Stony Brook, New York.
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17
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Louvet E, Yoshida A, Kumeta M, Takeyasu K. Probing the stiffness of isolated nucleoli by atomic force microscopy. Histochem Cell Biol 2014; 141:365-81. [PMID: 24297448 DOI: 10.1007/s00418-013-1167-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/24/2013] [Indexed: 11/24/2022]
Abstract
In eukaryotic cells, ribosome biogenesis occurs in the nucleolus, a membraneless nuclear compartment. Noticeably, the nucleolus is also involved in several nuclear functions, such as cell cycle regulation, non-ribosomal ribonucleoprotein complex assembly, aggresome formation and some virus assembly. The most intriguing question about the nucleolus is how such dynamics processes can occur in such a compact compartment. We hypothesized that its structure may be rather flexible. To investigate this, we used atomic force microscopy (AFM) on isolated nucleoli. Surface topography imaging revealed the beaded structure of the nucleolar surface. With the AFM's ability to measure forces, we were able to determine the stiffness of isolated nucleoli. We could establish that the nucleolar stiffness varies upon drastic morphological changes induced by transcription and proteasome inhibition. Furthermore, upon ribosomal proteins and LaminB1 knockdowns, the nucleolar stiffness was increased. This led us to propose a model where the nucleolus has steady-state stiffness dependent on ribosome biogenesis activity and requires LaminB1 for its flexibility.
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Affiliation(s)
- Emilie Louvet
- Graduate School of Biostudies, Kyoto University, Kyoto, 606-8501, Japan,
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18
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Wada K, Sato M, Araki N, Kumeta M, Hirai Y, Takeyasu K, Furukawa K, Horigome T. Dynamics of WD-repeat containing proteins in SSU processome components. Biochem Cell Biol 2014; 92:191-9. [PMID: 24754225 DOI: 10.1139/bcb-2014-0007] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Nine WD-repeat containing proteins in human SSU processome components have been found in a HeLa cell nuclear matrix fraction. In these proteins, t-UTP sub-complex components, i.e., CIRH1A, UTP15, and WDR43, were shown to be immobilized in the fibrillar centers of nucleoli in living cells. In this study, the dynamics of the remaining six proteins fused with green fluorescent protein (GFP), i.e., PWP2-GFP, TBL3-GFP, GFP-UTP18, GFP-NOL10, GFP-WDR46, and GFP-WDSOF1, were examined in living cells. The findings were as follows. (i) The majority of UTP-B sub-complex components, i.e., PWP2-GFP, TBL3-GFP, and GFP-UTP18, are localized to the dense fibrillar component and granular component regions in nucleoli; (ii) When rRNA transcription is suppressed, the majority of GFP-fused UTP-B sub-complex components are localized in the cap and body regions of nucleoli. (iii) The mobility of these proteins except for GFP-WDSOF1, and half of GFP-UTP18 and GFP-WDR46, respectively, is very low in living cells. (iv) When rRNA transcription is suppressed, the mobility of these proteins except for GFP-WDSOF1 is accelerated but still slow. These findings and others suggest that these WD-repeat proteins other than GFP-WDSOF1 found in the nuclear matrix fraction bind tightly to some macro-protein complexes and act as a scaffold or a core for the complexes in nucleoli.
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Affiliation(s)
- Kouko Wada
- a Graduate School of Science and Technology, Department of Chemistry, Faculty of Science, Niigata University, Igarashi-2, Nishi-ku, Niigata 950-2181, Japan
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19
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Kumeta M, Gilmore JL, Umeshima H, Ishikawa M, Kitajiri SI, Horigome T, Kengaku M, Takeyasu K. Caprice/MISP is a novel F-actin bundling protein critical for actin-based cytoskeletal reorganizations. Genes Cells 2014; 19:338-49. [DOI: 10.1111/gtc.12131] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Accepted: 12/18/2013] [Indexed: 02/02/2023]
Affiliation(s)
- Masahiro Kumeta
- Graduate School of Biostudies; Kyoto University; Kyoto 606-8501 Japan
| | - Jamie L. Gilmore
- Graduate School of Biostudies; Kyoto University; Kyoto 606-8501 Japan
| | - Hiroki Umeshima
- Institute for Integrated Cell-Material Sciences (iCeMS); Kyoto University; Kyoto 606-8501 Japan
| | - Masaaki Ishikawa
- Graduate School of Medicine; Kyoto University; Kyoto 606-8507 Japan
| | | | - Tsuneyoshi Horigome
- Graduate School of Science and Technology; Niigata University; Niigata 950-2181 Japan
| | - Mineko Kengaku
- Institute for Integrated Cell-Material Sciences (iCeMS); Kyoto University; Kyoto 606-8501 Japan
| | - Kunio Takeyasu
- Graduate School of Biostudies; Kyoto University; Kyoto 606-8501 Japan
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