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Jang S, Engelman AN. Capsid-host interactions for HIV-1 ingress. Microbiol Mol Biol Rev 2023; 87:e0004822. [PMID: 37750702 PMCID: PMC10732038 DOI: 10.1128/mmbr.00048-22] [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: 09/27/2023] Open
Abstract
The HIV-1 capsid, composed of approximately 1,200 copies of the capsid protein, encases genomic RNA alongside viral nucleocapsid, reverse transcriptase, and integrase proteins. After cell entry, the capsid interacts with a myriad of host factors to traverse the cell cytoplasm, pass through the nuclear pore complex (NPC), and then traffic to chromosomal sites for viral DNA integration. Integration may very well require the dissolution of the capsid, but where and when this uncoating event occurs remains hotly debated. Based on size constraints, a long-prevailing view was that uncoating preceded nuclear transport, but recent research has indicated that the capsid may remain largely intact during nuclear import, with perhaps some structural remodeling required for NPC traversal. Completion of reverse transcription in the nucleus may further aid capsid uncoating. One canonical type of host factor, typified by CPSF6, leverages a Phe-Gly (FG) motif to bind capsid. Recent research has shown these peptides reside amid prion-like domains (PrLDs), which are stretches of protein sequence devoid of charged residues. Intermolecular PrLD interactions along the exterior of the capsid shell impart avid host factor binding for productive HIV-1 infection. Herein we overview capsid-host interactions implicated in HIV-1 ingress and discuss important research questions moving forward. Highlighting clinical relevance, the long-acting ultrapotent inhibitor lenacapavir, which engages the same capsid binding pocket as FG host factors, was recently approved to treat people living with HIV.
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Affiliation(s)
- Sooin Jang
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
- Department of Medicine, Harvard Medical School, Boston, Massachusetts, USA
| | - Alan N. Engelman
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
- Department of Medicine, Harvard Medical School, Boston, Massachusetts, USA
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Le Coz C, Nguyen DN, Su C, Nolan BE, Albrecht AV, Xhani S, Sun D, Demaree B, Pillarisetti P, Khanna C, Wright F, Chen PA, Yoon S, Stiegler AL, Maurer K, Garifallou JP, Rymaszewski A, Kroft SH, Olson TS, Seif AE, Wertheim G, Grant SFA, Vo LT, Puck JM, Sullivan KE, Routes JM, Zakharova V, Shcherbina A, Mukhina A, Rudy NL, Hurst ACE, Atkinson TP, Boggon TJ, Hakonarson H, Abate AR, Hajjar J, Nicholas SK, Lupski JR, Verbsky J, Chinn IK, Gonzalez MV, Wells AD, Marson A, Poon GMK, Romberg N. Constrained chromatin accessibility in PU.1-mutated agammaglobulinemia patients. J Exp Med 2021; 218:212070. [PMID: 33951726 PMCID: PMC8105723 DOI: 10.1084/jem.20201750] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Revised: 02/09/2021] [Accepted: 03/16/2021] [Indexed: 12/19/2022] Open
Abstract
The pioneer transcription factor (TF) PU.1 controls hematopoietic cell fate by decompacting stem cell heterochromatin and allowing nonpioneer TFs to enter otherwise inaccessible genomic sites. PU.1 deficiency fatally arrests lymphopoiesis and myelopoiesis in mice, but human congenital PU.1 disorders have not previously been described. We studied six unrelated agammaglobulinemic patients, each harboring a heterozygous mutation (four de novo, two unphased) of SPI1, the gene encoding PU.1. Affected patients lacked circulating B cells and possessed few conventional dendritic cells. Introducing disease-similar SPI1 mutations into human hematopoietic stem and progenitor cells impaired early in vitro B cell and myeloid cell differentiation. Patient SPI1 mutations encoded destabilized PU.1 proteins unable to nuclear localize or bind target DNA. In PU.1-haploinsufficient pro–B cell lines, euchromatin was less accessible to nonpioneer TFs critical for B cell development, and gene expression patterns associated with the pro– to pre–B cell transition were undermined. Our findings molecularly describe a novel form of agammaglobulinemia and underscore PU.1’s critical, dose-dependent role as a hematopoietic euchromatin gatekeeper.
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Affiliation(s)
- Carole Le Coz
- Division of Immunology and Allergy, Children's Hospital of Philadelphia, Philadelphia, PA
| | - David N Nguyen
- Division of Infectious Diseases, Department of Medicine, University of California San Francisco, San Francisco, CA.,Department of Microbiology and Immunology, University of California San Francisco, San Francisco, CA.,Diabetes Center, University of California San Francisco, San Francisco, CA.,Innovative Genomics Institute, University of California Berkeley, Berkeley, CA.,Gladstone-University of California San Francisco Institute of Genomic Immunology, San Francisco, CA
| | - Chun Su
- Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, PA.,Center for Spatial and Functional Genomics, Children's Hospital of Philadelphia, Philadelphia, PA
| | - Brian E Nolan
- Division of Rheumatology, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL.,Department of Pediatrics, Feinberg School of Medicine, Northwestern University, Chicago, IL
| | - Amanda V Albrecht
- Department of Chemistry and Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA
| | - Suela Xhani
- Department of Chemistry and Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA
| | - Di Sun
- Division of Immunology and Allergy, Children's Hospital of Philadelphia, Philadelphia, PA
| | - Benjamin Demaree
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, CA.,University of California Berkeley-University of California San Francisco Graduate Program in Bioengineering, University of California, San Francisco, CA
| | - Piyush Pillarisetti
- Division of Immunology and Allergy, Children's Hospital of Philadelphia, Philadelphia, PA
| | - Caroline Khanna
- Division of Immunology and Allergy, Children's Hospital of Philadelphia, Philadelphia, PA
| | - Francis Wright
- Division of Infectious Diseases, Department of Medicine, University of California San Francisco, San Francisco, CA.,Department of Microbiology and Immunology, University of California San Francisco, San Francisco, CA
| | - Peixin Amy Chen
- Department of Microbiology and Immunology, University of California San Francisco, San Francisco, CA.,Diabetes Center, University of California San Francisco, San Francisco, CA.,Innovative Genomics Institute, University of California Berkeley, Berkeley, CA.,Gladstone-University of California San Francisco Institute of Genomic Immunology, San Francisco, CA
| | - Samuel Yoon
- Division of Immunology and Allergy, Children's Hospital of Philadelphia, Philadelphia, PA
| | - Amy L Stiegler
- Departments of Pharmacology, Yale University, New Haven, CT
| | - Kelly Maurer
- Division of Immunology and Allergy, Children's Hospital of Philadelphia, Philadelphia, PA
| | - James P Garifallou
- Center for Applied Genomics, Children's Hospital of Philadelphia, Philadelphia, PA
| | - Amy Rymaszewski
- Division of Allergy and Immunology, Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI
| | - Steven H Kroft
- Department of Pathology, Medical College of Wisconsin, Milwaukee, WI
| | - Timothy S Olson
- Division of Oncology, Children's Hospital of Philadelphia, Philadelphia, PA.,Department of Pediatrics, Perelman School of Medicine, Philadelphia, PA
| | - Alix E Seif
- Division of Oncology, Children's Hospital of Philadelphia, Philadelphia, PA.,Department of Pediatrics, Perelman School of Medicine, Philadelphia, PA
| | - Gerald Wertheim
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Philadelphia, PA.,Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Struan F A Grant
- Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, PA.,Department of Pediatrics, Perelman School of Medicine, Philadelphia, PA.,Division of Diabetes and Endocrinology, Children's Hospital of Philadelphia, Philadelphia, PA.,Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Linda T Vo
- Diabetes Center, University of California San Francisco, San Francisco, CA.,Innovative Genomics Institute, University of California Berkeley, Berkeley, CA
| | - Jennifer M Puck
- Division of Allergy, Immunology, and Bone Marrow Transplantation, Department of Pediatrics, University of California, San Francisco, CA.,University of California San Francsico Institute for Human Genetics and Smith Cardiovascular Research Institute, University of California, San Francisco, CA.,UCSF Helen Diller Family Comprehensive Cancer Center, University of California San Francisco, San Francisco, CA
| | - Kathleen E Sullivan
- Division of Immunology and Allergy, Children's Hospital of Philadelphia, Philadelphia, PA.,Department of Pediatrics, Perelman School of Medicine, Philadelphia, PA.,Institute for Immunology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - John M Routes
- Division of Allergy and Immunology, Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI
| | - Viktoria Zakharova
- Laboratory of Molecular Biology, Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology, Moscow, Russia
| | - Anna Shcherbina
- Department of Immunology, Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology, Moscow, Russia
| | - Anna Mukhina
- Department of Immunology, Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology, Moscow, Russia
| | - Natasha L Rudy
- Department of Genetics, University of Alabama at Birmingham, Birmingham, AL
| | - Anna C E Hurst
- Department of Genetics, University of Alabama at Birmingham, Birmingham, AL.,Department of Pediatrics, University of Alabama at Birmingham, Birmingham, AL
| | - T Prescott Atkinson
- Department of Pediatrics, University of Alabama at Birmingham, Birmingham, AL
| | - Titus J Boggon
- Departments of Pharmacology, Yale University, New Haven, CT.,Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT
| | - Hakon Hakonarson
- Center for Applied Genomics, Children's Hospital of Philadelphia, Philadelphia, PA.,Department of Pediatrics, Perelman School of Medicine, Philadelphia, PA
| | - Adam R Abate
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, CA.,University of California Berkeley-University of California San Francisco Graduate Program in Bioengineering, University of California, San Francisco, CA.,Chan Zuckerberg Biohub, San Francisco, CA
| | - Joud Hajjar
- William T. Shearer Center for Human Immunobiology, Texas Children's Hospital, Houston, TX.,Department of Immunology, Allergy and Rheumatology, Baylor College of Medicine, Houston, TX
| | - Sarah K Nicholas
- William T. Shearer Center for Human Immunobiology, Texas Children's Hospital, Houston, TX.,Department of Immunology, Allergy and Rheumatology, Baylor College of Medicine, Houston, TX
| | - James R Lupski
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX.,Texas Children's Hospital, Houston, TX.,Baylor-Hopkins Center for Mendelian Genomics, Houston, TX
| | - James Verbsky
- Division of Allergy and Immunology, Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI
| | - Ivan K Chinn
- William T. Shearer Center for Human Immunobiology, Texas Children's Hospital, Houston, TX.,Department of Immunology, Allergy and Rheumatology, Baylor College of Medicine, Houston, TX
| | - Michael V Gonzalez
- Center for Applied Genomics, Children's Hospital of Philadelphia, Philadelphia, PA
| | - Andrew D Wells
- Center for Spatial and Functional Genomics, Children's Hospital of Philadelphia, Philadelphia, PA.,Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Philadelphia, PA.,Institute for Immunology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Alex Marson
- Division of Infectious Diseases, Department of Medicine, University of California San Francisco, San Francisco, CA.,Department of Microbiology and Immunology, University of California San Francisco, San Francisco, CA.,Diabetes Center, University of California San Francisco, San Francisco, CA.,Innovative Genomics Institute, University of California Berkeley, Berkeley, CA.,Gladstone-University of California San Francisco Institute of Genomic Immunology, San Francisco, CA.,Chan Zuckerberg Biohub, San Francisco, CA.,Parker Institute for Cancer Immunotherapy, San Francisco, CA
| | - Gregory M K Poon
- Department of Chemistry and Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA
| | - Neil Romberg
- Division of Immunology and Allergy, Children's Hospital of Philadelphia, Philadelphia, PA.,Department of Pediatrics, Perelman School of Medicine, Philadelphia, PA.,Institute for Immunology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
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3
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Bedwell GJ, Engelman AN. Factors that mold the nuclear landscape of HIV-1 integration. Nucleic Acids Res 2021; 49:621-635. [PMID: 33337475 PMCID: PMC7826272 DOI: 10.1093/nar/gkaa1207] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Accepted: 11/26/2020] [Indexed: 12/17/2022] Open
Abstract
The integration of retroviral reverse transcripts into the chromatin of the cells that they infect is required for virus replication. Retroviral integration has far-reaching consequences, from perpetuating deadly human diseases to molding metazoan evolution. The lentivirus human immunodeficiency virus 1 (HIV-1), which is the causative agent of the AIDS pandemic, efficiently infects interphase cells due to the active nuclear import of its preintegration complex (PIC). To enable integration, the PIC must navigate the densely-packed nuclear environment where the genome is organized into different chromatin states of varying accessibility in accordance with cellular needs. The HIV-1 capsid protein interacts with specific host factors to facilitate PIC nuclear import, while additional interactions of viral integrase, the enzyme responsible for viral DNA integration, with cellular nuclear proteins and nucleobases guide integration to specific chromosomal sites. HIV-1 integration favors transcriptionally active chromatin such as speckle-associated domains and disfavors heterochromatin including lamina-associated domains. In this review, we describe virus-host interactions that facilitate HIV-1 PIC nuclear import and integration site targeting, highlighting commonalities among factors that participate in both of these steps. We moreover discuss how the nuclear landscape influences HIV-1 integration site selection as well as the establishment of active versus latent virus infection.
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Affiliation(s)
- Gregory J Bedwell
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, MA 02215, USA
- Department of Medicine, Harvard Medical School, Boston, MA 02115, USA
| | - Alan N Engelman
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, MA 02215, USA
- Department of Medicine, Harvard Medical School, Boston, MA 02115, USA
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4
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Jin X, Hapsari ND, Lee S, Jo K. DNA binding fluorescent proteins as single-molecule probes. Analyst 2020; 145:4079-4095. [DOI: 10.1039/d0an00218f] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
DNA binding fluorescent proteins are useful probes for a broad range of biological applications.
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Affiliation(s)
- Xuelin Jin
- Department of Chemistry and Interdisciplinary Program of Integrated Biotechnology
- Sogang University
- Seoul
- Republic of Korea
| | - Natalia Diyah Hapsari
- Department of Chemistry and Interdisciplinary Program of Integrated Biotechnology
- Sogang University
- Seoul
- Republic of Korea
- Chemistry Education Program
| | - Seonghyun Lee
- Department of Chemistry and Interdisciplinary Program of Integrated Biotechnology
- Sogang University
- Seoul
- Republic of Korea
| | - Kyubong Jo
- Department of Chemistry and Interdisciplinary Program of Integrated Biotechnology
- Sogang University
- Seoul
- Republic of Korea
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5
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Heterogeneous Nuclear Ribonucleoprotein A1 and Lamin A/C Modulate Nucleocytoplasmic Shuttling of Avian Reovirus p17. J Virol 2019; 93:JVI.00851-19. [PMID: 31375578 DOI: 10.1128/jvi.00851-19] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Accepted: 07/17/2019] [Indexed: 01/15/2023] Open
Abstract
Avian reovirus (ARV) p17 protein continuously shuttles between the nucleus and the cytoplasm via transcription-dependent and chromosome region maintenance 1 (CRM1)-independent mechanisms. Nevertheless, whether cellular proteins modulate nucleocytoplasmic shuttling of p17 remains unknown. This is the first report that heterogeneous nuclear ribonucleoprotein (hnRNP) A1 serves as a carrier protein to modulate nucleocytoplasmic shuttling of p17. Both in vitro and in vivo studies indicated that direct interaction of p17 with hnRNP A1 maps within the amino terminus (amino acids [aa] 19 to 40) of p17 and the Gly-rich region of the C terminus of hnRNP A1. Furthermore, our results reveal that the formation of p17-hnRNP A1-transportin 1 carrier-cargo complex is required to modulate p17 nuclear import. Utilizing sequence and mutagenesis analyses, we have identified nuclear export signal (NES) 19LSLRELAI26 of p17. Mutations of these residues causes a nuclear retention of p17. In this work, we uncovered that the N-terminal 21 amino acids (aa 19 to 40) of p17 that comprise the NES can modulate both p17 and hnRNP A1 interaction and nucleocytoplasmic shuttling of p17. In this work, the interaction site of p17 with lamin A/C was mapped within the amino terminus (aa 41 to 60) of p17 and p17 colocalized with lamin A/C at the nuclear envelope. Knockdown of hnRNP A1 or lamin A/C led to inhibition of nucleocytoplasmic shuttling of p17 and reduced virus yield. Collectively, the results of this study provide mechanistic insights into hnRNP A1 and lamin A/C-modulated nucleocytoplasmic shuttling of the ARV p17 protein.IMPORTANCE Avian reoviruses (ARVs) cause considerable economic losses in the poultry industry. The ARV p17 protein continuously shuttles between the nucleus and the cytoplasm to regulate several cellular signaling pathways and interacts with several cellular proteins to cause translation shutoff, cell cycle arrest, and autophagosome formation, all of which enhance virus replication. To date the mechanisms underlying nucleocytoplasmic shuttling of p17 remain largely unknown. Here we report that hnRNP A1 and lamin A/C serve as carrier and mediator proteins to modulate nucleocytoplasmic shuttling of p17. The formation of p17-hnRNP A1-transportin 1 carrier-cargo complex is required to modulate p17 nuclear import. Furthermore, we have identified an NES-containing nucleocytoplasmic shuttling domain (aa 19 to 40) of p17 that is critical for binding to hnRNP A1 and for nucleocytoplasmic shuttling of p17. This study provides novel insights into how hnRNP A1 and lamin A/C modulate nucleocytoplasmic shuttling of the ARV p17 protein.
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6
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Sun L, Telles E, Karl M, Cheng F, Luetteke N, Sotomayor EM, Miller RH, Seto E. Loss of HDAC11 ameliorates clinical symptoms in a multiple sclerosis mouse model. Life Sci Alliance 2018; 1:e201800039. [PMID: 30456376 PMCID: PMC6238389 DOI: 10.26508/lsa.201800039] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 09/16/2018] [Accepted: 09/17/2018] [Indexed: 01/12/2023] Open
Abstract
In an animal model for multiple sclerosis, the absence of HDAC11 reduces clinical severity, spinal cord demyelination, and immune cell infiltration, suggesting that HDAC11 is a promising target for MS treatment. Multiple sclerosis (MS) is a chronic, immune-mediated, demyelinating disease of the central nervous system (CNS). There is no known cure for MS, and currently available drugs for managing this disease are only effective early on and have many adverse side effects. Results from recent studies suggest that histone deacetylase (HDAC) inhibitors may be useful for the treatment of autoimmune and inflammatory diseases such as MS. However, the underlying mechanisms by which HDACs influence immune-mediated diseases such as MS are unclear. More importantly, the question of which specific HDAC(s) are suitable drug targets for the potential treatment of MS remains unanswered. Here, we investigate the functional role of HDAC11 in experimental autoimmune encephalomyelitis, a mouse model for MS. Our results indicate that the loss of HDAC11 in KO mice significantly reduces clinical severity and demyelination of the spinal cord in the post-acute phase of experimental autoimmune encephalomyelitis. The absence of HDAC11 leads to reduced immune cell infiltration into the CNS and decreased monocytes and myeloid DCs in the chronic progressive phase of the disease. Mechanistically, HDAC11 controls the expression of the pro-inflammatory chemokine C–C motif ligand 2 (CCL2) gene by enabling the binding of PU.1 transcription factor to the CCL2 promoter. Our results reveal a novel pathophysiological function for HDAC11 in CNS demyelinating diseases, and warrant further investigations into the potential use of HDAC11-specific inhibitors for the treatment of chronic progressive MS.
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Affiliation(s)
- Lei Sun
- George Washington University Cancer Center, George Washington University School of Medicine and Health Sciences, Washington, DC, USA.,Department of Biochemistry and Molecular Medicine, George Washington University School of Medicine and Health Sciences, Washington, DC, USA
| | - Elphine Telles
- George Washington University Cancer Center, George Washington University School of Medicine and Health Sciences, Washington, DC, USA
| | - Molly Karl
- Department of Anatomy and Cell Biology, George Washington University School of Medicine and Health Sciences, Washington, DC, USA
| | - Fengdong Cheng
- George Washington University Cancer Center, George Washington University School of Medicine and Health Sciences, Washington, DC, USA
| | - Noreen Luetteke
- George Washington University Cancer Center, George Washington University School of Medicine and Health Sciences, Washington, DC, USA
| | - Eduardo M Sotomayor
- George Washington University Cancer Center, George Washington University School of Medicine and Health Sciences, Washington, DC, USA
| | - Robert H Miller
- Department of Anatomy and Cell Biology, George Washington University School of Medicine and Health Sciences, Washington, DC, USA
| | - Edward Seto
- George Washington University Cancer Center, George Washington University School of Medicine and Health Sciences, Washington, DC, USA.,Department of Biochemistry and Molecular Medicine, George Washington University School of Medicine and Health Sciences, Washington, DC, USA
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Lasitschka F, Giese T, Paparella M, Kurzhals SR, Wabnitz G, Jacob K, Gras J, Bode KA, Heninger AK, Sziskzai T, Samstag Y, Leszinski C, Jocher B, Al-Saeedi M, Meuer SC, Schröder-Braunstein J. Human monocytes downregulate innate response receptors following exposure to the microbial metabolite n-butyrate. IMMUNITY INFLAMMATION AND DISEASE 2017; 5:480-492. [PMID: 28681454 PMCID: PMC5691313 DOI: 10.1002/iid3.184] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Revised: 05/26/2017] [Accepted: 06/12/2017] [Indexed: 12/23/2022]
Abstract
Introduction Hyporesponsiveness of human lamina propria immune cells to microbial and nutritional antigens represents one important feature of intestinal homeostasis. It is at least partially mediated by low expression of the innate response receptors CD11b, CD14, CD16 as well as the cystine‐glutamate transporter xCT on these cells. Milieu‐specific mechanisms leading to the down‐regulation of these receptors on circulating monocytes, the precursor cells of resident macrophages, are mostly unknown. Methods Here, we addressed the question whether the short chain fatty acid n‐butyrate, a fermentation product of the mammalian gut microbiota exhibiting histone deacetylase inhibitory activity, is able to modulate expression of these receptors in human circulating monocytes. Results Exposure to n‐butyrate resulted in the downregulation of CD11b, CD14, as well as CD16 surface expression on circulating monocytes. XCT transcript levels in circulating monocytes were also reduced following exposure to n‐butyrate. Importantly, treatment resulted in the downregulation of protein and gene expression of the transcription factor PU.1, which was shown to be at least partially required for the expression of CD16 in circulating monocytes. PU.1 expression in resident macrophages in situ was observed to be substantially lower in healthy when compared to inflamed colonic mucosa. Conclusions In summary, the intestinal microbiota may support symbiosis with the human host organism by n‐butyrate mediated downregulation of protein and gene expression of innate response receptors as well as xCT on circulating monocytes following recruitment to the lamina propria. Downregulation of CD16 gene expression may at least partially be caused at the transcriptional level by the n‐butyrate mediated decrease in expression of the transcription factor PU.1 in circulating monocytes.
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Affiliation(s)
- Felix Lasitschka
- Institute of Pathology, University Hospital Heidelberg, Im Neuenheimer Feld 224, 69120, Heidelberg, Germany.,Institute of Immunology, University Hospital Heidelberg, Im Neuenheimer Feld 305, 69120, Heidelberg, Germany
| | - Thomas Giese
- Institute of Immunology, University Hospital Heidelberg, Im Neuenheimer Feld 305, 69120, Heidelberg, Germany
| | - Marco Paparella
- Institute of Immunology, University Hospital Heidelberg, Im Neuenheimer Feld 305, 69120, Heidelberg, Germany
| | - Stefan R Kurzhals
- Institute of Immunology, University Hospital Heidelberg, Im Neuenheimer Feld 305, 69120, Heidelberg, Germany
| | - Guido Wabnitz
- Institute of Immunology, University Hospital Heidelberg, Im Neuenheimer Feld 305, 69120, Heidelberg, Germany
| | - Katrin Jacob
- Institute of Immunology, University Hospital Heidelberg, Im Neuenheimer Feld 305, 69120, Heidelberg, Germany
| | - Judith Gras
- Institute of Immunology, University Hospital Heidelberg, Im Neuenheimer Feld 305, 69120, Heidelberg, Germany
| | - Konrad A Bode
- Department of Infectious Diseases, Medical Microbiology and Hygiene, University Hospital Heidelberg, Im Neuenheimer Feld 324, 69120, Heidelberg, Germany
| | - Anne-Kristin Heninger
- Institute of Immunology, University Hospital Heidelberg, Im Neuenheimer Feld 305, 69120, Heidelberg, Germany
| | - Timea Sziskzai
- Department of Anesthesiology, University Hospital Heidelberg, Im Neuenheimer Feld 110, 69120, Heidelberg, Germany
| | - Yvonne Samstag
- Institute of Immunology, University Hospital Heidelberg, Im Neuenheimer Feld 305, 69120, Heidelberg, Germany
| | - Cornelia Leszinski
- Department of Surgery, St. Vincentius Hospital, Holzstr. 4a, 67346, Speyer, Germany
| | - Bettina Jocher
- Department of Surgery, University Hospital Heidelberg, Im Neuenheimer Feld 110, 69120, Heidelberg, Germany
| | - Mohammed Al-Saeedi
- Department of Surgery, University Hospital Heidelberg, Im Neuenheimer Feld 110, 69120, Heidelberg, Germany
| | - Stefan C Meuer
- Institute of Immunology, University Hospital Heidelberg, Im Neuenheimer Feld 305, 69120, Heidelberg, Germany
| | - Jutta Schröder-Braunstein
- Institute of Immunology, University Hospital Heidelberg, Im Neuenheimer Feld 305, 69120, Heidelberg, Germany
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8
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Wang M, Liu Z, Liu C, Wu T, Cai F, Wang Q, Su X, Shi Y. PU.1 is involved in the immune response to Aspergillus fumigatus through upregulating Dectin-1 expression. BMC Infect Dis 2016; 16:297. [PMID: 27306059 PMCID: PMC4910222 DOI: 10.1186/s12879-016-1632-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Accepted: 06/07/2016] [Indexed: 02/06/2023] Open
Abstract
Background Invasive aspergillosis is a life-threatening disease, and its incidence has increased in the recent past. Dectin-1 recognizes β-glucans and mediates innate immune responses to Aspergillus fumigatus. Transcription factor PU.1 has been the focus of recent research due to its role in inflammation and infection. However, its role in Dectin-1 regulation during A. fumigatus infection remains to be elucidated. Methods THP-1 cells were stimulated with A. fumigatus conidia. We then used real-time RT-PCR, Western blot, and immunofluorescence assays to analyze the mRNA and protein levels and cellular distribution, respectively, of Dectin-1 and PU.1 in stimulated THP-1 cells. Additionally, we used the luciferase reporter assays, chromatin immunoprecipitation (ChIP) assays, electrophoretic mobility shift assays (EMSA), and RNA interference experiments to investigate the role of PU.1 in Dectin-1 regulation. Results Our results revealed that Dectin-1 mRNA and protein levels as well as the PU.1 protein level were increased in THP-1 cells stimulated with A. fumigatus conidia, while the mRNA expression level did not significantly change between the stimulated and control groups. We also observed that PU.1 translocated into the nucleus in stimulated THP-1 cells. The results of the luciferase reporter assay showed that PU.1 promoted human Dectin-1 (hDectin-1) gene activity. ChIP and EMSA indicated that PU.1 could bind with hDectin-1 gene promoter at three potential transcription factor-binding sites (TFBSs). In addition, knockdown of PU.1 significantly decreased Dectin-1 expression. Conclusions This study demonstrated the novel role of PU.1 in the immune response to A. fumigatus through upregulation of Dectin-1 expression and its translocation to the nucleus in A. fumigatus-stimulated THP-1 cells.
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Affiliation(s)
- Min Wang
- Department of Respiratory and Critical Care Medicine, Jinling Hospital, Medical School of Nanjing University, 305 East Zhongshan Road, Nanjing, China
| | | | | | - Ting Wu
- Department of Respiratory and Critical Care Medicine, Jinling Hospital, Medical School of Nanjing University, 305 East Zhongshan Road, Nanjing, China
| | - Feng Cai
- Department of Respiratory and Critical Care Medicine, Jinling Hospital, Medical School of Nanjing University, 305 East Zhongshan Road, Nanjing, China
| | - Quan Wang
- Department of Respiratory Medicine, BenQ Medical Center, Nanjing, China
| | - Xin Su
- Department of Respiratory and Critical Care Medicine, Jinling Hospital, Medical School of Nanjing University, 305 East Zhongshan Road, Nanjing, China.
| | - Yi Shi
- Department of Respiratory and Critical Care Medicine, Jinling Hospital, Medical School of Nanjing University, 305 East Zhongshan Road, Nanjing, China.
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9
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Dickmanns A, Kehlenbach RH, Fahrenkrog B. Nuclear Pore Complexes and Nucleocytoplasmic Transport: From Structure to Function to Disease. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2015; 320:171-233. [PMID: 26614874 DOI: 10.1016/bs.ircmb.2015.07.010] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Nucleocytoplasmic transport is an essential cellular activity and occurs via nuclear pore complexes (NPCs) that reside in the double membrane of the nuclear envelope. Significant progress has been made during the past few years in unravelling the ultrastructural organization of NPCs and their constituents, the nucleoporins, by cryo-electron tomography and X-ray crystallography. Mass spectrometry and genomic approaches have provided deeper insight into the specific regulation and fine tuning of individual nuclear transport pathways. Recent research has also focused on the roles nucleoporins play in health and disease, some of which go beyond nucleocytoplasmic transport. Here we review emerging results aimed at understanding NPC architecture and nucleocytoplasmic transport at the atomic level, elucidating the specific function individual nucleoporins play in nuclear trafficking, and finally lighting up the contribution of nucleoporins and nuclear transport receptors in human diseases, such as cancer and certain genetic disorders.
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Affiliation(s)
- Achim Dickmanns
- Abteilung für Molekulare Strukturbiologie, Institut für Mikrobiologie und Genetik, Göttinger Zentrum für Molekulare Biowissenschaften, Georg-August-Universität Göttingen, Göttingen, Germany
| | - Ralph H Kehlenbach
- Department of Molecular Biology, Faculty of Medicine, Georg-August-University of Göttingen, Göttingen, Germany
| | - Birthe Fahrenkrog
- Institute of Molecular Biology and Medicine, Université Libre de Bruxelles, Charleroi, Belgium
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10
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Onder Z, Moroianu J. Nuclear import of cutaneous beta genus HPV8 E7 oncoprotein is mediated by hydrophobic interactions between its zinc-binding domain and FG nucleoporins. Virology 2013; 449:150-62. [PMID: 24418548 DOI: 10.1016/j.virol.2013.11.020] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Revised: 10/08/2013] [Accepted: 11/11/2013] [Indexed: 10/25/2022]
Abstract
We have previously discovered and characterized the nuclear import pathways for the E7 oncoproteins of mucosal alpha genus HPVs, type 16 and 11. Here we investigated the nuclear import of cutaneous beta genus HPV8 E7 protein using confocal microscopy after transfections of HeLa cells with EGFP-8E7 and mutant plasmids and nuclear import assays in digitonin-permeabilized HeLa cells. We determined that HPV8 E7 contains a nuclear localization signal (NLS) within its zinc-binding domain that mediates its nuclear import. Furthermore, we discovered that a mostly hydrophobic patch 65LRLFV69 within the zinc-binding domain is essential for the nuclear import and localization of HPV8 E7 via hydrophobic interactions with the FG nucleoporins Nup62 and Nup153. Substitution of the hydrophobic residues within the 65LRLFV69 patch to alanines, and not R66A mutation, disrupt the interactions between the 8E7 zinc-binding domain and Nup62 and Nup153 and consequently inhibit nuclear import of HPV8 E7.
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Affiliation(s)
- Zeynep Onder
- Biology Department, Boston College, Chestnut Hill, MA 02467, USA
| | - Junona Moroianu
- Biology Department, Boston College, Chestnut Hill, MA 02467, USA.
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11
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Eberhard J, Onder Z, Moroianu J. Nuclear import of high risk HPV16 E7 oncoprotein is mediated by its zinc-binding domain via hydrophobic interactions with Nup62. Virology 2013; 446:334-45. [PMID: 24074597 DOI: 10.1016/j.virol.2013.08.017] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2013] [Revised: 07/08/2013] [Accepted: 08/14/2013] [Indexed: 11/15/2022]
Abstract
We previously discovered that nuclear import of high risk HPV16 E7 is mediated by a cNLS located within the zinc-binding domain via a pathway that is independent of karyopherins/importins (Angeline et al., 2003; Knapp et al., 2009). In this study we continued our characterization of the cNLS and nuclear import pathway of HPV16 E7. We find that an intact zinc-binding domain is essential for the cNLS function in mediating nuclear import of HPV16 E7. Mutagenesis of cysteine residues to alanine in each of the two CysXXCys motifs involved in zinc-binding changes the nuclear localization of the EGFP-16E7 and 2xEGFP-16E7 mutants. We further discover that a patch of hydrophobic residues, 65LRLCV69, within the zinc-binding domain of HPV16 E7 mediates its nuclear import via hydrophobic interactions with the FG domain of the central channel nucleoporin Nup62.
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Affiliation(s)
- Jeremy Eberhard
- Biology Department, Boston College, Chestnut Hill, MA 02467, USA
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12
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McKee CH, Onder Z, Ashok A, Cardoso R, Moroianu J. Characterization of the transport signals that mediate the nucleocytoplasmic traffic of low risk HPV11 E7. Virology 2013; 443:113-22. [PMID: 23725695 PMCID: PMC3758764 DOI: 10.1016/j.virol.2013.04.031] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Revised: 03/21/2013] [Accepted: 04/29/2013] [Indexed: 10/26/2022]
Abstract
We previously discovered that nuclear import of low risk HPV11 E7 is mediated by its zinc-binding domain via a pathway that is independent of karyopherins/importins (Piccioli et al., 2010. Virology 407, 100-109). In this study we mapped and characterized a leucine-rich nuclear export signal (NES), 76IRQLQDLLL84, within the zinc-binding domain that mediates the nuclear export of HPV11 E7 in a CRM1-dependent manner. We also identified a mostly hydrophobic patch 65VRLVV69 within the zinc-binding domain that mediates nuclear import of HPV11 E7 via hydrophobic interactions with the FG-repeats domain of Nup62. Substitutions of hydrophobic residues to alanine within the 65VRLVV69 sequence disrupt the nuclear localization of 11E7, whereas the R66A mutation has no effect. Overall the data support a model of nuclear entry of HPV11 E7 protein via hydrophobic interactions with FG nucleoporins at the nuclear pore complex.
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Affiliation(s)
- Courtney H. McKee
- Biology Department, Boston College, Chestnut Hill, MA 02467, United States
| | - Zeynep Onder
- Biology Department, Boston College, Chestnut Hill, MA 02467, United States
| | - Aditya Ashok
- Biology Department, Boston College, Chestnut Hill, MA 02467, United States
| | - Rebeca Cardoso
- Biology Department, Boston College, Chestnut Hill, MA 02467, United States
| | - Junona Moroianu
- Biology Department, Boston College, Chestnut Hill, MA 02467, United States
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13
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Hayashi R, Takeuchi N, Ueda T. Nuclear Respiratory Factor 2β (NRF-2β) recruits NRF-2α to the nucleus by binding to importin-α:β via an unusual monopartite-type nuclear localization signal. J Mol Biol 2013; 425:3536-48. [PMID: 23856623 DOI: 10.1016/j.jmb.2013.07.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2013] [Revised: 07/03/2013] [Accepted: 07/04/2013] [Indexed: 11/28/2022]
Abstract
Nuclear respiratory factor 2 (NRF-2) is a mammalian transcription factor composed of two distinct and unrelated proteins: NRF-2α, which binds to DNA through its Ets domain, and NRF-2β, which contains the transcription activation domain. The activity of NRF-2 in neurons is regulated by nuclear localization; however, the mechanism by which NRF-2 is imported into the nucleus remains unknown. By using in vitro nuclear import assays and immuno-cytofluorescence, we dissect the nuclear import pathways of NRF-2. We show that both NRF-2α and NRF-2β contain intrinsic nuclear localization signals (NLSs): the Ets domain within NRF-2α and the NLS within NRF-2β (amino acids 311/321: EEPPAKRQCIE) that is recognized by importin-α:β. When NRF-2α and NRF-2β form a complex, the nuclear import of NRF-2αβ becomes strictly dependent on the NLS within NRF-2β. Therefore, the nuclear import mechanism of NRF-2 is unique among Ets factors. The NRF-2β NLS contains only two lysine/arginine residues, unlike other known importin-α:β-dependent NLSs. Using ELISA-based binding assays, we show that it is bound by importin-α in almost the same manner and with similar affinity to that of the classical monopartite NLSs, such as c-myc and SV40 T-antigen NLSs. However, the part of the tryptophan array of importin-α that is essential for the recognition of classical monopartite NLSs by generating apolar pockets for the P3 and the P5 lysine/arginine side chains is not required for the recognition of the NRF-2β NLS. We conclude that the NRF-2β NLS is an unusual but is, nevertheless, a bona fide monopartite-type NLS.
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Affiliation(s)
- Rippei Hayashi
- Department of Medical Genome Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwanoha, Kashiwa, Chiba Prefecture 277-8562, Japan.
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14
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Dynein Light Chain 1 (DYNLT1) Interacts with Normal and Oncogenic Nucleoporins. PLoS One 2013; 8:e67032. [PMID: 23840580 PMCID: PMC3694108 DOI: 10.1371/journal.pone.0067032] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Accepted: 05/13/2013] [Indexed: 12/18/2022] Open
Abstract
The chimeric oncoprotein NUP98-HOXA9 results from the t(7;11)(p15;p15) chromosomal translocation and is associated with acute myeloid leukemia. It causes aberrant gene regulation and leukemic transformation through mechanisms that are not fully understood. NUP98-HOXA9 consists of an N-terminal portion of the nucleoporin NUP98 that contains many FG repeats fused to the DNA-binding homeodomain of HOXA9. We used a Cytotrap yeast two-hybrid assay to identify proteins that interact with NUP98-HOXA9. We identified Dynein Light Chain 1 (DYNLT1), an integral 14 KDa protein subunit of the large microtubule-based cytoplasmic dynein complex, as an interaction partner of NUP98-HOXA9. Binding was confirmed by in vitro pull down and co-immunoprecipitation assays and the FG repeat region of NUP98-HOXA9 was shown to be essential for the interaction. RNAi-mediated knockdown of DYNLT1 resulted in reduction of the ability of NUP98-HOXA9 to activate transcription and also inhibited the ability of NUP98-HOXA9 to induce proliferation of primary human hematopoietic CD34+ cells. DYNLT1 also showed a strong interaction with wild-type NUP98 and other nucleoporins containing FG repeats. Immunofluorescence analysis showed that DYNLT1 localizes primarily to the nuclear periphery, where it co-localizes with the nuclear pore complex, and to the cytoplasm. Deletion studies showed that the interactions of the nucleoporins with DYNLT1 are dependent predominantly on the C-terminal half of the DYNLT1. These data show for the first time that DYNLT1 interacts with nucleoporins and plays a role in the dysregulation of gene expression and induction of hematopoietic cell proliferation by the leukemogenic nucleoporin fusion, NUP98-HOXA9.
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15
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Sprater F, Hovden AO, Appel S. Expression of ESE-3 isoforms in immunogenic and tolerogenic human monocyte-derived dendritic cells. PLoS One 2012. [PMID: 23185370 PMCID: PMC3501485 DOI: 10.1371/journal.pone.0049577] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Dendritic cells (DC) are the only hematopoietic cells expressing the epithelial specific Ets transcription factor ESE-3. Here we analyzed presence and quantity of isoforms ESE-3a, ESE-3b and ESE-3j in various immunogenic and tolerogenic human monocyte-derived DC (moDC) and blood DC populations using quantitative real time PCR and immunoblot analyses. ESE-3a and ESE-3b were detectable in all moDC populations with ESE-3b being the main transcript. ESE-3b expression was upregulated in immunogenic moDC and downregulated in tolerogenic moDC compared to immature moDC. ESE-3a had similar transcript levels in immature and immunogenic moDC and had very low levels in tolerogenic moDC. In blood DC populations only splice variant ESE-3b was detectable. ESE-3j was not detectable in any of the DC populations. These findings suggest that ESE-3b is the functionally most important ESE-3 isoform in DC.
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Affiliation(s)
- Florian Sprater
- Broegelmann Research Laboratory, The Gade Institute, University of Bergen, Bergen, Norway
| | - Arnt-Ove Hovden
- Broegelmann Research Laboratory, The Gade Institute, University of Bergen, Bergen, Norway
| | - Silke Appel
- Broegelmann Research Laboratory, The Gade Institute, University of Bergen, Bergen, Norway
- * E-mail:
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16
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Woodward CL, Chow SA. The nuclear pore complex: a new dynamic in HIV-1 replication. Nucleus 2012; 1:18-22. [PMID: 21327100 DOI: 10.4161/nucl.1.1.10571] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2009] [Revised: 11/07/2009] [Accepted: 11/10/2009] [Indexed: 01/08/2023] Open
Abstract
The ability to traverse an intact nuclear envelope and productively infect non-dividing cells is a salient feature of human immunodeficiency virus type 1 (HIV-1) and other lentiviruses, but the viral factors and mechanism of nuclear entry have not been defined. We have recently reported a functional role for the nucleoporin NUP153 in the nuclear import of the HIV-1 preintegration complex (PIC). Our findings suggest that HIV-1 sub-viral particles gain access to the nucleus by interacting directly with the nuclear pore complex (NPC) via the binding of PIC-associated integrase (IN) to the C-terminal domain of NUP153. This article discusses how NPC conformation and constitution might influence nuclear import of the PIC, and the subsequent integration of the viral cDNA into actively transcribed genes.
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Affiliation(s)
- Cora L Woodward
- Department of Molecular and Medical Pharmacology, and UCLA AIDS Institute, UCLA School of Medicine, Los Angeles, CA, USA
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17
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Sarma NJ, Yaseen NR. Amino-terminal enhancer of split (AES) interacts with the oncoprotein NUP98-HOXA9 and enhances its transforming ability. J Biol Chem 2011; 286:38989-9001. [PMID: 21937451 DOI: 10.1074/jbc.m111.297952] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
NUP98-HOXA9 is the prototype of NUP98 fusion oncoproteins that cause acute myeloid leukemia. It consists of an N-terminal FG-rich portion of the nucleoporin NUP98 fused to the homeodomain region of the homeobox protein HOXA9, and acts as an aberrant transcription factor. To identify interacting partners of NUP98-HOXA9, we used a cytoplasmic yeast two-hybrid assay to avoid the nonspecific trans-activation that would occur with the traditional yeast two-hybrid assay due to the transactivating properties of NUP98-HOXA9. We identified amino-terminal enhancer of split (AES), a transcriptional regulator of the transducin-like enhancer/Groucho family as a novel interaction partner of NUP98-HOXA9. The interaction was confirmed by in vitro pulldown and co-immunoprecipitation assays and was shown to require the FG repeat region of NUP98-HOXA9. Immunofluorescence analysis showed that AES localizes primarily to the interior of the nucleus. AES also showed a strong interaction with wild-type NUP98. AES augmented the transcriptional activity of NUP98-HOXA9. In the presence of NUP98-HOXA9, AES caused an increase in long-term proliferation of primary human CD34+ cells with a marked increase in the numbers of primitive cells. These effects of AES were not observed in the absence of NUP98-HOXA9. AES knockdown diminished the transcriptional and proliferative effects of NUP98-HOXA9. AES caused a shift away from the erythroid lineage in cells expressing NUP98-HOXA9. These data establish AES as an interacting partner of NUP98-HOXA9 and show that it cooperates with NUP98-HOXA9 in transcriptional regulation and cell transformation.
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Affiliation(s)
- Nayan J Sarma
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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18
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Ando Y, Tomaru Y, Morinaga A, Burroughs AM, Kawaji H, Kubosaki A, Kimura R, Tagata M, Ino Y, Hirano H, Chiba J, Suzuki H, Carninci P, Hayashizaki Y. Nuclear pore complex protein mediated nuclear localization of dicer protein in human cells. PLoS One 2011; 6:e23385. [PMID: 21858095 PMCID: PMC3156128 DOI: 10.1371/journal.pone.0023385] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2011] [Accepted: 07/15/2011] [Indexed: 12/22/2022] Open
Abstract
Human DICER1 protein cleaves double-stranded RNA into small sizes, a crucial step in production of single-stranded RNAs which are mediating factors of cytoplasmic RNA interference. Here, we clearly demonstrate that human DICER1 protein localizes not only to the cytoplasm but also to the nucleoplasm. We also find that human DICER1 protein associates with the NUP153 protein, one component of the nuclear pore complex. This association is detected predominantly in the cytoplasm but is also clearly distinguishable at the nuclear periphery. Additional characterization of the NUP153-DICER1 association suggests NUP153 plays a crucial role in the nuclear localization of the DICER1 protein.
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Affiliation(s)
| | | | | | | | - Hideya Kawaji
- RIKEN Omics Science Center, Yokohama, Kanagawa, Japan
| | | | - Ryuichiro Kimura
- Department of Biological Science and Technology, Tokyo University of Science, Noda, Chiba, Japan
| | - Maiko Tagata
- Department of Biological Science and Technology, Tokyo University of Science, Noda, Chiba, Japan
| | - Yoko Ino
- Supramolecular Biology, International Graduate School of Arts and Sciences, Yokohama City University, Yokohama, Kanagawa, Japan
| | - Hisashi Hirano
- Supramolecular Biology, International Graduate School of Arts and Sciences, Yokohama City University, Yokohama, Kanagawa, Japan
| | - Joe Chiba
- Department of Biological Science and Technology, Tokyo University of Science, Noda, Chiba, Japan
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Takeda A, Sarma NJ, Abdul-Nabi AM, Yaseen NR. Inhibition of CRM1-mediated nuclear export of transcription factors by leukemogenic NUP98 fusion proteins. J Biol Chem 2010; 285:16248-57. [PMID: 20233715 PMCID: PMC2871492 DOI: 10.1074/jbc.m109.048785] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2009] [Revised: 02/15/2010] [Indexed: 12/29/2022] Open
Abstract
NUP98 is a nucleoporin that plays complex roles in the nucleocytoplasmic trafficking of macromolecules. Rearrangements of the NUP98 gene in human leukemia result in the expression of numerous fusion oncoproteins whose effect on nucleocytoplasmic trafficking is poorly understood. The present study was undertaken to determine the effects of leukemogenic NUP98 fusion proteins on CRM1-mediated nuclear export. NUP98-HOXA9, a prototypic NUP98 fusion, inhibited the nuclear export of two known CRM1 substrates: mutated cytoplasmic nucleophosmin and HIV-1 Rev. In vitro binding assays revealed that NUP98-HOXA9 binds CRM1 through the FG repeat motif in a Ran-GTP-dependent manner similar to but stronger than the interaction between CRM1 and its export substrates. Two NUP98 fusions, NUP98-HOXA9 and NUP98-DDX10, whose fusion partners are structurally and functionally unrelated, interacted with endogenous CRM1 in myeloid cells as shown by co-immunoprecipitation. These leukemogenic NUP98 fusion proteins interacted with CRM1, Ran, and the nucleoporin NUP214 in a manner fundamentally different from that of wild-type NUP98. NUP98-HOXA9 and NUP98-DDX10 formed characteristic aggregates within the nuclei of a myeloid cell line and primary human CD34+ cells and caused aberrant localization of CRM1 to these aggregates. These NUP98 fusions caused nuclear accumulation of two transcription factors, NFAT and NFkappaB, that are regulated by CRM1-mediated export. The nuclear entrapment of NFAT and NFkappaB correlated with enhanced transcription from promoters responsive to these transcription factors. Taken together, the results suggest a new mechanism by which NUP98 fusions dysregulate transcription and cause leukemia, namely, inhibition of CRM1-mediated nuclear export with aberrant nuclear retention of transcriptional regulators.
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MESH Headings
- Active Transport, Cell Nucleus/genetics
- Amino Acid Motifs
- Antigens, CD34
- Cell Nucleus/genetics
- Cell Nucleus/metabolism
- Cell Nucleus/pathology
- Guanosine Triphosphate/genetics
- Guanosine Triphosphate/metabolism
- HIV-1/genetics
- HIV-1/metabolism
- Homeodomain Proteins/genetics
- Homeodomain Proteins/metabolism
- Humans
- K562 Cells
- Karyopherins/genetics
- Karyopherins/metabolism
- Leukemia/genetics
- Leukemia/metabolism
- Leukemia/pathology
- Mutation
- NF-kappa B/genetics
- NF-kappa B/metabolism
- NFATC Transcription Factors/genetics
- NFATC Transcription Factors/metabolism
- Nuclear Pore Complex Proteins/genetics
- Nuclear Pore Complex Proteins/metabolism
- Oncogene Proteins, Fusion/genetics
- Oncogene Proteins, Fusion/metabolism
- Promoter Regions, Genetic/genetics
- Receptors, Cytoplasmic and Nuclear/genetics
- Receptors, Cytoplasmic and Nuclear/metabolism
- Transcription, Genetic/genetics
- ran GTP-Binding Protein/genetics
- ran GTP-Binding Protein/metabolism
- rev Gene Products, Human Immunodeficiency Virus/genetics
- rev Gene Products, Human Immunodeficiency Virus/metabolism
- Exportin 1 Protein
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Affiliation(s)
- Akiko Takeda
- From the Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Nayan J. Sarma
- From the Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Anmaar M. Abdul-Nabi
- From the Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Nabeel R. Yaseen
- From the Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri 63110
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20
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Jerke U, Tkachuk S, Kiyan J, Stepanova V, Kusch A, Hinz M, Dietz R, Haller H, Fuhrman B, Dumler I. Stat1 nuclear translocation by nucleolin upon monocyte differentiation. PLoS One 2009; 4:e8302. [PMID: 20011528 PMCID: PMC2788426 DOI: 10.1371/journal.pone.0008302] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2009] [Accepted: 11/19/2009] [Indexed: 01/14/2023] Open
Abstract
BACKGROUND Members of the signal transducer and activator of transcription (Stat) family of transcription factors traverse the nuclear membrane through a specialized structure, called the nuclear pore complex (NPC), which represents a selective filter for the import of proteins. Karyophilic molecules can bind directly to a subset of proteins of the NPC, collectively called nucleoporins. Alternatively, the transport is mediated via a carrier molecule belonging to the importin/karyopherin superfamily, which transmits the import into the nucleus through the NPC. METHODOLOGY/PRINCIPAL FINDINGS In this study, we provide evidence for an alternative Stat1 nuclear import mechanism, which is mediated by the shuttle protein nucleolin. We observed Stat1-nucleolin association, nuclear translocation and specific binding to the regulatory DNA element GAS. Using expression of nucleolin transgenes, we found that the nuclear localization signal (NLS) of nucleolin is responsible for Stat1 nuclear translocation. We show that this mechanism is utilized upon differentiation of myeloid cells and is specific for the differentiation step from monocytes to macrophages. CONCLUSIONS/SIGNIFICANCE Our data add the nucleolin-Stat1 complex as a novel functional partner for the cell differentiation program, which is uniquely poised to regulate the transcription machinery via Stat1 and nuclear metabolism via nucleolin.
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Affiliation(s)
- Uwe Jerke
- Hannover Medical School, Hannover, Germany.
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21
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Cao X, Littlejohn J, Rodarte C, Zhang L, Martino B, Rascoe P, Hamid K, Jupiter D, Smythe WR. Up-regulation of Bcl-xl by hepatocyte growth factor in human mesothelioma cells involves ETS transcription factors. THE AMERICAN JOURNAL OF PATHOLOGY 2009; 175:2207-16. [PMID: 19834061 DOI: 10.2353/ajpath.2009.090070] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Bcl-xl and the hepatocyte growth factor (HGF) receptor c-Met are both highly expressed in mesotheliomas, where they protect cells from apoptosis and can confer resistance to conventional therapeutic agents. In our current study, we investigate a model for the transcriptional control of Bcl-xl that involves ETS transcription factors and the HGF/Met axis. In addition, the effects of activated c-Met on the phosphorylation of the ETS family transcriptional factors were examined. The transient expression of ETS-2 and PU.1 cDNAs in mesothelioma cell lines resulted in an increase in the promoter activity of Bcl-xl and consequently in its mRNA and protein expression levels, whereas the transcriptional repressor Tel suppressed Bcl-xl transcription. The activation of the HGF/Met axis led to rapid phosphorylation of ETS family transcription factors in mesothelioma cells through the mitogen-activated protein kinase pathway and via nuclear accumulation of ETS-2 and PU.1. A chromatin immunoprecipitation assay further demonstrated that the activation of c-Met enhanced the binding of ETS transcriptional factors to the Bcl-x promoter. Finally, we determined the Bcl-xl and phosphorylated c-Met expression levels in mesothelioma patient samples; these data suggest a strong correlation between Bcl-xl and phosphorylated c-Met levels. Taken together, these findings support a role for c-Met as an inhibitor of apoptosis and an activator of Bcl-xl.
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Affiliation(s)
- Xiaobo Cao
- Department of Surgery, Scott & White Memorial Hospital and Clinic, Temple, TX 76508, USA
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22
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Vázquez-Iglesias L, Lostalé-Seijo I, Martínez-Costas J, Benavente J. Avian reovirus sigmaA localizes to the nucleolus and enters the nucleus by a nonclassical energy- and carrier-independent pathway. J Virol 2009; 83:10163-75. [PMID: 19640987 PMCID: PMC2747991 DOI: 10.1128/jvi.01080-09] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2009] [Accepted: 07/16/2009] [Indexed: 12/24/2022] Open
Abstract
Avian reovirus sigmaA is a double-stranded RNA (dsRNA)-binding protein that has been shown to stabilize viral core particles and to protect the virus against the antiviral action of interferon. To continue with the characterization of this viral protein, we have investigated its intracellular distribution in avian cells. Most sigmaA accumulates into cytoplasmic viral factories of infected cells, and yet a significant fraction was detected in the nucleolus. The protein also localizes in the nucleolus of transfected cells, suggesting that nucleolar targeting is not facilitated by the viral infection or by viral factors. Assays performed in both intact cells and digitonin-permeabilized cells demonstrate that sigmaA is able to enter the nucleus via a nucleoporin-dependent nondiffusional mechanism that does not require added cytosolic factors or energy input. These results indicate that sigmaA by itself is able to penetrate into the nucleus using a process that is mechanistically different from the classical nuclear localization signal/importin pathway. On the other hand, two sigmaA arginines that are necessary for dsRNA binding are also required for nucleolar localization, suggesting that dsRNA-binding and nucleolar targeting are intimately linked properties of the viral protein.
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Affiliation(s)
- Lorena Vázquez-Iglesias
- Departamento de Bioquímica y Biología Molecular, Facultad de Farmacia, Universidad de Santiago de Compostela, Santiago de Compostela, Spain
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Integrase interacts with nucleoporin NUP153 to mediate the nuclear import of human immunodeficiency virus type 1. J Virol 2009; 83:6522-33. [PMID: 19369352 DOI: 10.1128/jvi.02061-08] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The ability to traverse an intact nuclear envelope and productively infect nondividing cells is a salient feature of human immunodeficiency virus type 1 (HIV-1) and other lentiviruses, but the viral factors and mechanism of nuclear entry have not been defined. HIV-1 integrase (IN) is implicated to play a role in the nuclear import of the virus, but the cellular pathway for IN trafficking and the role of IN in mediating the nuclear import of viral particles are unknown. Using a semipermeabilized cell assay, we observed that the nuclear import of IN was not the result of passive diffusion but occurred independently of cytosolic factors, metabolic energy, and the classical receptor-mediated, Ran-dependent import pathways. To determine if IN enters the nucleus by interacting with the nucleopore complex (NPC), we found that IN bound directly with the FxFG-rich C-terminal domain of nucleoporin 153 (NUP153C). When added in excess to the import assay, NUP153C inhibited the nuclear import of IN. Known binding partners of NUP153C competed with IN for binding with NUP153 and also inhibited the nuclear import of IN. In cultured cells, overexpression of NUP153C reduced the infectivity of an HIV-derived vector by interfering with the nuclear translocation of the viral cDNA. These results support a functional role for the IN-NUP153 interaction in HIV-1 replication and suggest that HIV-1 subviral particles gain access to the nucleus by interacting directly with the NPC via the binding of particle-associated IN to NUP153C.
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25
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Wolf C, Mofrad MRK. On the octagonal structure of the nuclear pore complex: insights from coarse-grained models. Biophys J 2008; 95:2073-85. [PMID: 18487299 PMCID: PMC2483776 DOI: 10.1529/biophysj.108.130336] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2008] [Accepted: 04/24/2008] [Indexed: 11/18/2022] Open
Abstract
The basic structure of the nuclear pore complex (NPC), conserved across almost all organisms from yeast to humans, persists in featuring an octagonal symmetry involving the nucleoporins that constitute the NPC ring. In this article, we seek to understand and evaluate the potential biomechanical reasons for this eightfold symmetry. Our analytical investigation shows that the eightfold symmetry maximizes the bending stiffness of each of the eight NPC spokes while our computational analyses identify the most likely deformation modes, frequencies, and associated kinetic energies of the NPC. These modes have energies close to other published findings using membrane analysis of the nuclear membrane pore opening, and deformation states in agreement with experimental observations. A better understanding of NPC mechanics is essential for characterizing the nucleocytoplasmic transport, which has a central importance in cell biology.
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Affiliation(s)
- Christopher Wolf
- Molecular Cell Biomechanics Laboratory, Department of Bioengineering, University of California, Berkeley, California 94720, USA
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26
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Kwok JC, Perdomo J, Chong BH. Identification of a monopartite sequence in PU.1 essential for nuclear import, DNA-binding and transcription of myeloid-specific genes. J Cell Biochem 2008; 101:1456-74. [PMID: 17340619 DOI: 10.1002/jcb.21264] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The Ets transcription factor PU.1 is an essential regulator of normal hematopoiesis, especially within the myeloid lineage. As such, endogenous PU.1 predominantly localizes to the nucleus of mammalian cells to facilitate gene regulation. However, to date, little is known regarding the mechanisms of PU.1 nuclear transport. We found, using HeLa and RAW 264.7 macrophage cells, that PU.1 enters the nucleus via passive diffusion and active transport. The latter can be facilitated by: (i) the classical pathway requiring importin alpha and beta; (ii) the non-classical pathway requiring only importin beta; or (iii) direct interaction with nucleoporins. A group of six positively charged lysine or arginine residues within the Ets DNA-binding domain was determined to be crucial in active nuclear import. These residues directly interact with importin beta to facilitate a predominantly non-classical import pathway. Furthermore, luciferase reporter assays demonstrated that these same six amino acids are crucial for PU.1-mediated transcriptional activation of myeloid-specific genes. Indeed, these residues may represent a consensus sequence vital for nuclear import, DNA-binding and transcriptional activity of Ets family members. By identifying and characterizing the mechanisms of PU.1 nuclear import and the specific amino acids involved, this report may provide insights into the molecular basis of diseases.
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Affiliation(s)
- Juliana C Kwok
- Centre for Thrombosis and Vascular Research, Department of Medicine, St. George Clinical School, University of New South Wales, Sydney, New South Wales, Australia.
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Van Impe K, Hubert T, De Corte V, Vanloo B, Boucherie C, Vandekerckhove J, Gettemans J. A new role for nuclear transport factor 2 and Ran: nuclear import of CapG. Traffic 2008; 9:695-707. [PMID: 18266911 DOI: 10.1111/j.1600-0854.2008.00720.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The small GTPase Ran plays a central role in nucleocytoplasmic transport. Nuclear transport of Ran itself depends on nuclear transport factor 2 (NTF2). Here, we report that NTF2 and Ran control nuclear import of the filamentous actin capping protein CapG. In digitonin-permeabilized cells, neither GTPgammaS nor the GTP hydrolysis-deficient Ran mutant RanQ69L affect transit of CapG to the nucleus in the presence of cytosol. Obstruction of nucleoporins prevents nuclear transport of CapG, and we show that CapG binds to nucleoporin62. In addition, CapG interacts with NTF2, associates with Ran and is furthermore able to bind the NTF2-Ran complex. NTF2-Ran interaction is required for CapG nuclear import. This is corroborated by a NTF2 mutant with reduced affinity for Ran and a Ran mutant that does not bind NTF2, both of which prevent CapG import. Thus, a ubiquitously expressed protein shuttles to the nucleus through direct association with NTF2 and Ran. The role of NTF2 may therefore not be solely confined to sustaining the Ran gradient in cells.
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Affiliation(s)
- Katrien Van Impe
- Department of Medical Protein Research, VIB, B-9000 Ghent, Belgium
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28
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Lim RYH, Ullman KS, Fahrenkrog B. Biology and biophysics of the nuclear pore complex and its components. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2008; 267:299-342. [PMID: 18544502 DOI: 10.1016/s1937-6448(08)00632-1] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Nucleocytoplasmic exchange of proteins and ribonucleoprotein particles occurs via nuclear pore complexes (NPCs) that reside in the double membrane of the nuclear envelope (NE). Significant progress has been made during the past few years in obtaining better structural resolution of the three-dimensional architecture of NPC with the help of cryo-electron tomography and atomic structures of domains from nuclear pore proteins (nucleoporins). Biophysical and imaging approaches have helped elucidate how nucleoporins act as a selective barrier in nucleocytoplasmic transport. Nucleoporins act not only in trafficking of macromolecules but also in proper microtubule attachment to kinetochores, in the regulation of gene expression and signaling events associated with, for example, innate and adaptive immunity, development and neurodegenerative disorders. Recent research has also been focused on the dynamic processes of NPC assembly and disassembly that occur with each cell cycle. Here we review emerging results aimed at understanding the molecular arrangement of the NPC and how it is achieved, defining the roles of individual nucleoporins both at the NPC and at other sites within the cell, and finally deciphering how the NPC serves as both a barrier and a conduit of active transport.
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Affiliation(s)
- Roderick Y H Lim
- M.E. Müller Institute for Structural Biology, Biozentrum, University of Basel, Klingelbergstrasse 70, 4056 Basel, Switzerland
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29
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Tsuji T, Sheehy N, Gautier VW, Hayakawa H, Sawa H, Hall WW. The nuclear import of the human T lymphotropic virus type I (HTLV-1) tax protein is carrier- and energy-independent. J Biol Chem 2007; 282:13875-83. [PMID: 17344183 DOI: 10.1074/jbc.m611629200] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
HTLV-1 is the etiologic agent of the adult T cell leukemialymphoma (ATLL). The viral regulatory protein Tax plays a central role in leukemogenesis as a transcriptional transactivator of both viral and cellular gene expression, and this requires Tax activity in both the cytoplasm and the nucleus. In the present study, we have investigated the mechanisms involved in the nuclear localization of Tax. Employing a GFP fusion expression system and a range of Tax mutants, we could confirm that the N-terminal 60 amino acids, and specifically residues within the zinc finger motif in this region, are important for nuclear localization. Using an in vitro nuclear import assay, it could be demonstrated that the transportation of Tax to the nucleus required neither energy nor carrier proteins. Specific and direct binding between Tax and p62, a nucleoporin with which the importin beta family of proteins have been known to interact was also observed. The nuclear import activity of wild type Tax and its mutants and their binding affinity for p62 were also clearly correlated, suggesting that the entry of Tax into the nucleus involves a direct interaction with nucleoporins within the nuclear pore complex (NPC). The nuclear export of Tax was also shown to be carrier independent. It could be also demonstrated that Tax it self may have a carrier function and that the NF-kappaB subunit p65 could be imported into the nucleus by Tax. These studies suggest that Tax could alter the nucleocytoplasmic distribution of cellular proteins, and this could contribute to the deregulation of cellular processes observed in HTLV-1 infection.
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Affiliation(s)
- Takahiro Tsuji
- Centre for Research in Infectious Disease, School of Medicine & Medical Science, University College Dublin, Belfield, Dublin 4, Ireland
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30
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Abstract
The ETS (E26 Transformation-specific Sequence) factors are comprised of a family of transcription factors that share a highly conserved DNA binding domain. Although originally described for their role as protooncogenes in the development of several types of human cancer, they have subsequently been shown to regulate a wide variety of biological processes including cellular growth and differentiation under normal and pathological conditions. As transcription factors, they can either function as activators or repressors of gene expression. Several ETS family members are expressed in cells of vascular origin, including endothelial cells and vascular smooth muscle cells, where they regulate the expression of a number of vascular-specific genes. In the past few years, emerging evidence supports a novel role for selected ETS family members in the regulation of vascular inflammation and remodeling. ETS factor expression can be induced by proinflammatory cytokines, growth factors, and vasoactive peptides. Examples of some of the target genes regulated by ETS factors include adhesion molecules, chemokines, and matrix metalloproteinases. Targeted disruption of selected ETS family members such as Ets-1 in mice is associated with marked reductions in the recruitment of inflammatory cells and vascular remodeling in response to systemic administration of the vasoactive peptide angiotensin II. The purpose of this review is to provide an overview of recent advances that have been made in defining a role for selected members of the ETS transcription factor family in the regulation of vascular-specific gene expression, vascular inflammation, and remodeling.
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Affiliation(s)
- Peter Oettgen
- Division of Cardiology, Beth Israel Deaconess Medical Center, Boston, MA 02115, USA.
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31
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Zhong H, Shio H, Yaseen NR. Ultrastructural nuclear import assay. Methods 2006; 39:309-15. [PMID: 16935003 DOI: 10.1016/j.ymeth.2006.07.012] [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] [Accepted: 06/20/2006] [Indexed: 11/16/2022] Open
Abstract
Electron microscopy (EM) has been used for several decades to study the mechanisms of nuclear transport. In early studies of nuclear import, gold-conjugated nuclear proteins were microinjected into cells and followed by EM. As the components of the nuclear pore complex (NPC) and soluble mediators of nuclear import were cloned and characterized, gold-conjugated antibodies were utilized to sublocalize the components of the nuclear transport machinery by immuno-EM. Further, gold-conjugated recombinant proteins were used to probe permeabilized cells or isolated nuclear envelopes and characterize binding sites for these proteins at the NPC. More recently, recombinant gold-conjugated nuclear proteins were used in in vitro nuclear import assays to help dissect the mechanisms of nuclear import. We have used this ultrastructural nuclear import assay to study the nuclear import of the transcription factor PU.1. The results showed that this import requires energy but is carrier-independent. In the presence of energy, gold-conjugated PU.1 shifted to the nuclear side of the NPC and the inside of the nucleus. In conjunction with biochemical assays, these results indicated that this shift involved Ran-dependent binding of PU.1 to NUP153, a nucleoporin situated at the nuclear side of the NPC. Here we describe in detail the methods used in the ultrastructural nuclear import assay including preparation of recombinant protein, gold conjugation, in vitro nuclear import assay, electron microscopy, and data analysis.
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Affiliation(s)
- Hualin Zhong
- Department of Biological Sciences, Hunter College, City University of New York, New York, NY 10021, USA
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32
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Kikkert M, Hassink G, Wiertz E. The role of the ubiquitination machinery in dislocation and degradation of endoplasmic reticulum proteins. Curr Top Microbiol Immunol 2006; 300:57-93. [PMID: 16573237 DOI: 10.1007/3-540-28007-3_4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Ubiquitination is essential for the dislocation and degradation of proteins from the endoplasmic reticulum (ER). How exactly this is regulated is unknown at present. This review provides an overview of ubiquitin-conjugating enzymes (E2s) and ubiquitin ligases (E3s) with a role in the degradation of ER proteins. Their structure and functions are described, as well as their mutual interactions. Substrate specificity and functional redundancy of E3 ligases are discussed, and other components of the ER degradation machinery that may associate with the ubiquitination system are reviewed.
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Affiliation(s)
- M Kikkert
- Department of Medical Microbiology, Leiden University Medical Center (LUMC), Albinusdreef 2, 2333 ZA Leiden, The Netherlands.
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33
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Ball JR, Ullman KS. Versatility at the nuclear pore complex: lessons learned from the nucleoporin Nup153. Chromosoma 2005; 114:319-30. [PMID: 16133350 DOI: 10.1007/s00412-005-0019-3] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2005] [Revised: 07/08/2005] [Accepted: 07/10/2005] [Indexed: 10/25/2022]
Abstract
The vertebrate pore protein Nup153 plays pivotal roles in nuclear pore function. In addition to being important to pore architecture, Nup153 is a key participant in both import and export. The scope of Nup153 function also extends beyond the canonical view of the pore as a trafficking gateway. During the transition into mitosis, Nup153 directs proteins involved in membrane remodeling to the nuclear envelope. As cells exit mitosis, Nup153 is recruited to the chromosomal surface, where nuclear pores are formed anew in a complicated process still under much experimental scrutiny. In addition, Nup153 is targeted for protease cleavage during apoptosis and in response to certain viral infections, providing molecular insight into pore reconfiguration during cell response. Overall, the versatile nature of Nup153 underscores an emerging view of the nuclear pore at the nexus of many key cellular processes.
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Affiliation(s)
- Jennifer R Ball
- Department of Oncological Sciences, Huntsman Cancer Institute, 2000 Circle of Hope, University of Utah, Salt Lake City, UT 84112, USA
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Paulillo SM, Phillips EM, Köser J, Sauder U, Ullman KS, Powers MA, Fahrenkrog B. Nucleoporin domain topology is linked to the transport status of the nuclear pore complex. J Mol Biol 2005; 351:784-98. [PMID: 16045929 DOI: 10.1016/j.jmb.2005.06.034] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2005] [Revised: 06/08/2005] [Accepted: 06/13/2005] [Indexed: 11/30/2022]
Abstract
Nuclear pore complexes (NPCs) facilitate macromolecular exchange between the nucleus and cytoplasm of eukaryotic cells. The vertebrate NPC is composed of approximately 30 different proteins (nucleoporins), of which around one third contain phenylalanine-glycine (FG)-repeat domains that are thought to mediate the main interaction between the NPC and soluble transport receptors. We have recently shown that the FG-repeat domain of Nup153 is flexible within the NPC, although this nucleoporin is anchored to the nuclear side of the NPC. By using domain-specific antibodies, we have now mapped the domain topology of Nup214 in Xenopus oocytes and in human somatic cells by immuno-EM. We have found that whereas Nup214 is anchored to the cytoplasmic side of the NPC via its N-terminal and central domain, its FG-repeat domain appears flexible, residing on both sides of the NPC. Moreover, the spatial distribution of the FG-repeat domains of both Nup153 and Nup214 shifts in a transport-dependent manner, suggesting that the location of FG-repeat domains within the NPC correlates with cargo/receptor interactions and that they concomitantly move with cargo through the central pore of the NPC.
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Affiliation(s)
- Sara M Paulillo
- M.E. Müller Institute for Structural Biology, Biozentrum, University of Basel, Klingelbergstr. 70, 4056 Basel, Switzerland
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Wiemann S, Kolb-Kokocinski A, Poustka A. Alternative pre-mRNA processing regulates cell-type specific expression of the IL4l1 and NUP62 genes. BMC Biol 2005; 3:16. [PMID: 16029492 PMCID: PMC1198218 DOI: 10.1186/1741-7007-3-16] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2005] [Accepted: 07/19/2005] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Given the complexity of higher organisms, the number of genes encoded by their genomes is surprisingly small. Tissue specific regulation of expression and splicing are major factors enhancing the number of the encoded products. Commonly these mechanisms are intragenic and affect only one gene. RESULTS Here we provide evidence that the IL4I1 gene is specifically transcribed from the apparent promoter of the upstream NUP62 gene, and that the first two exons of NUP62 are also contained in the novel IL4I1_2 variant. While expression of IL4I1 driven from its previously described promoter is found mostly in B cells, the expression driven by the NUP62 promoter is restricted to cells in testis (Sertoli cells) and in the brain (e.g., Purkinje cells). Since NUP62 is itself ubiquitously expressed, the IL4I1_2 variant likely derives from cell type specific alternative pre-mRNA processing. CONCLUSION Comparative genomics suggest that the promoter upstream of the NUP62 gene originally belonged to the IL4I1 gene and was later acquired by NUP62 via insertion of a retroposon. Since both genes are apparently essential, the promoter had to serve two genes afterwards. Expression of the IL4I1 gene from the "NUP62" promoter and the tissue specific involvement of the pre-mRNA processing machinery to regulate expression of two unrelated proteins indicate a novel mechanism of gene regulation.
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Affiliation(s)
- Stefan Wiemann
- Molecular Genome Analysis, German Cancer Research Center, Im Neuenheimer Feld 580, Heidelberg, 69120, Germany
| | - Anja Kolb-Kokocinski
- Molecular Genome Analysis, German Cancer Research Center, Im Neuenheimer Feld 580, Heidelberg, 69120, Germany
| | - Annemarie Poustka
- Molecular Genome Analysis, German Cancer Research Center, Im Neuenheimer Feld 580, Heidelberg, 69120, Germany
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