1
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Szelenyi ER, Navarrete JS, Murry AD, Zhang Y, Girven KS, Kuo L, Cline MM, Bernstein MX, Burdyniuk M, Bowler B, Goodwin NL, Juarez B, Zweifel LS, Golden SA. An arginine-rich nuclear localization signal (ArgiNLS) strategy for streamlined image segmentation of single cells. Proc Natl Acad Sci U S A 2024; 121:e2320250121. [PMID: 39074275 PMCID: PMC11317604 DOI: 10.1073/pnas.2320250121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Accepted: 06/25/2024] [Indexed: 07/31/2024] Open
Abstract
High-throughput volumetric fluorescent microscopy pipelines can spatially integrate whole-brain structure and function at the foundational level of single cells. However, conventional fluorescent protein (FP) modifications used to discriminate single cells possess limited efficacy or are detrimental to cellular health. Here, we introduce a synthetic and nondeleterious nuclear localization signal (NLS) tag strategy, called "Arginine-rich NLS" (ArgiNLS), that optimizes genetic labeling and downstream image segmentation of single cells by restricting FP localization near-exclusively in the nucleus through a poly-arginine mechanism. A single N-terminal ArgiNLS tag provides modular nuclear restriction consistently across spectrally separate FP variants. ArgiNLS performance in vivo displays functional conservation across major cortical cell classes and in response to both local and systemic brain-wide AAV administration. Crucially, the high signal-to-noise ratio afforded by ArgiNLS enhances machine learning-automated segmentation of single cells due to rapid classifier training and enrichment of labeled cell detection within 2D brain sections or 3D volumetric whole-brain image datasets, derived from both staining-amplified and native signal. This genetic strategy provides a simple and flexible basis for precise image segmentation of genetically labeled single cells at scale and paired with behavioral procedures.
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Affiliation(s)
- Eric R. Szelenyi
- Center of Excellence in Neurobiology of Addiction, Pain, and Emotion, University of Washington, Seattle, WA98195
- Department of Biological Structure, University of Washington, Seattle, WA98195
| | - Jovana S. Navarrete
- Center of Excellence in Neurobiology of Addiction, Pain, and Emotion, University of Washington, Seattle, WA98195
- Department of Biological Structure, University of Washington, Seattle, WA98195
- Graduate Program in Neuroscience, University of Washington, Seattle, WA98195
| | - Alexandria D. Murry
- Center of Excellence in Neurobiology of Addiction, Pain, and Emotion, University of Washington, Seattle, WA98195
- Department of Biological Structure, University of Washington, Seattle, WA98195
| | - Yizhe Zhang
- Center of Excellence in Neurobiology of Addiction, Pain, and Emotion, University of Washington, Seattle, WA98195
- Department of Biological Structure, University of Washington, Seattle, WA98195
| | - Kasey S. Girven
- Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, WA 98195
| | - Lauren Kuo
- Center of Excellence in Neurobiology of Addiction, Pain, and Emotion, University of Washington, Seattle, WA98195
- Undergraduate Program in Biochemistry, University of Washington, Seattle, WA98195
| | - Marcella M. Cline
- Center of Excellence in Neurobiology of Addiction, Pain, and Emotion, University of Washington, Seattle, WA98195
- Department of Pharmacology, University of Washington, Seattle, WA98195
| | - Mollie X. Bernstein
- Center of Excellence in Neurobiology of Addiction, Pain, and Emotion, University of Washington, Seattle, WA98195
- Department of Pharmacology, University of Washington, Seattle, WA98195
| | | | - Bryce Bowler
- Department of Biological Structure, University of Washington, Seattle, WA98195
| | - Nastacia L. Goodwin
- Center of Excellence in Neurobiology of Addiction, Pain, and Emotion, University of Washington, Seattle, WA98195
- Department of Biological Structure, University of Washington, Seattle, WA98195
- Graduate Program in Neuroscience, University of Washington, Seattle, WA98195
| | - Barbara Juarez
- Center of Excellence in Neurobiology of Addiction, Pain, and Emotion, University of Washington, Seattle, WA98195
- Department of Pharmacology, University of Washington, Seattle, WA98195
- Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, WA98195
| | - Larry S. Zweifel
- Center of Excellence in Neurobiology of Addiction, Pain, and Emotion, University of Washington, Seattle, WA98195
- Department of Pharmacology, University of Washington, Seattle, WA98195
- Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, WA98195
| | - Sam A. Golden
- Center of Excellence in Neurobiology of Addiction, Pain, and Emotion, University of Washington, Seattle, WA98195
- Department of Biological Structure, University of Washington, Seattle, WA98195
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2
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Zhao H, Bi F, Li M, Diao Y, Zhang C. E3 ubiquitin ligase RNF180 impairs IPO4/SOX2 complex stability and inhibits SOX2-mediated malignancy in ovarian cancer. Cell Signal 2024; 113:110961. [PMID: 37923100 DOI: 10.1016/j.cellsig.2023.110961] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 10/17/2023] [Accepted: 10/30/2023] [Indexed: 11/07/2023]
Abstract
RING finger protein 180 (RNF180), an E3 ubiquitin ligase, is thought to be a tumor suppressor gene. However, the detailed mechanism of its effect on ovarian cancer (OV) has not been elucidated. Importin 4 (IPO4) which belongs to transport protein is reported to have cancer-promoting effects on OV. Here, we explored the potential signaling pathways related to RNF180 and IPO4. It was first verified that RNF180 is downregulated and IPO4 is upregulated in OV. By overexpressing or knocking down RNF180 in OV cells, we confirmed that RNF180 inhibited the malignant behaviors of OV cells both in vitro and in vivo. Bioinformatics analysis and proteomics experiments found that RNF180 could interact with IPO4 and promote the degradation of IPO4 through ubiquitination. In addition, overexpression of IPO4 removed the inhibitory effect of RNF180 on OV. We subsequently found that IPO4 could bind to the oncogene Sex determining Region Y-box 2 (SOX2). Knockdown of IPO4 in OV cells decreased SOX2 protein level in nucleus and promoted cyclin-dependent kinase inhibitory protein-1 (p21) expression. Overexpression of RNF180 also inhibited the expression of SOX2 in nucleus. All these results indicated that RNF180 inhibited the nuclear translocation of SOX2 by promoting ubiquitination of IPO4, which ultimately promoted the expression of p21 and then suppressed the progression of OV. This study verified the tumor suppressor effect of RNF180 on OV, elucidated the mechanism of the molecule network related to RNF180 and IPO4 in OV and identified for OV.
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Affiliation(s)
- Haiyan Zhao
- Department of Rheumatology and Immunology, Shengjing Hospital of China Medical University, Shenyang, Liaoning, China
| | - Fangfang Bi
- Department of Obstetrics and Gynecology, Shengjing Hospital of China Medical University, Shenyang, Liaoning, China
| | - Mengyuan Li
- Department of Obstetrics and Gynecology, Shengjing Hospital of China Medical University, Shenyang, Liaoning, China
| | - Yuhan Diao
- Department of Obstetrics and Gynecology, Shengjing Hospital of China Medical University, Shenyang, Liaoning, China
| | - Chen Zhang
- Department of Obstetrics and Gynecology, Shengjing Hospital of China Medical University, Shenyang, Liaoning, China.
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3
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Szelenyi ER, Navarrete JS, Murry AD, Zhang Y, Girven KS, Kuo L, Cline MM, Bernstein MX, Burdyniuk M, Bowler B, Goodwin NL, Juarez B, Zweifel LS, Golden SA. An arginine-rich nuclear localization signal (ArgiNLS) strategy for streamlined image segmentation of single-cells. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.22.568319. [PMID: 38045271 PMCID: PMC10690249 DOI: 10.1101/2023.11.22.568319] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2023]
Abstract
High-throughput volumetric fluorescent microscopy pipelines can spatially integrate whole-brain structure and function at the foundational level of single-cells. However, conventional fluorescent protein (FP) modifications used to discriminate single-cells possess limited efficacy or are detrimental to cellular health. Here, we introduce a synthetic and non-deleterious nuclear localization signal (NLS) tag strategy, called 'Arginine-rich NLS' (ArgiNLS), that optimizes genetic labeling and downstream image segmentation of single-cells by restricting FP localization near-exclusively in the nucleus through a poly-arginine mechanism. A single N-terminal ArgiNLS tag provides modular nuclear restriction consistently across spectrally separate FP variants. ArgiNLS performance in vivo displays functional conservation across major cortical cell classes, and in response to both local and systemic brain wide AAV administration. Crucially, the high signal-to-noise ratio afforded by ArgiNLS enhances ML-automated segmentation of single-cells due to rapid classifier training and enrichment of labeled cell detection within 2D brain sections or 3D volumetric whole-brain image datasets, derived from both staining-amplified and native signal. This genetic strategy provides a simple and flexible basis for precise image segmentation of genetically labeled single-cells at scale and paired with behavioral procedures.
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Affiliation(s)
- Eric R. Szelenyi
- University of Washington Center of Excellence in Neurobiology of Addiction, Pain, and Emotion (NAPE), Seattle, WA, USA
- University of Washington, Department of Biological Structure, Seattle, WA, USA
| | - Jovana S. Navarrete
- University of Washington Center of Excellence in Neurobiology of Addiction, Pain, and Emotion (NAPE), Seattle, WA, USA
- University of Washington, Department of Biological Structure, Seattle, WA, USA
- University of Washington, Graduate Program in Neuroscience, Seattle, WA, USA
| | - Alexandria D. Murry
- University of Washington Center of Excellence in Neurobiology of Addiction, Pain, and Emotion (NAPE), Seattle, WA, USA
- University of Washington, Department of Biological Structure, Seattle, WA, USA
| | - Yizhe Zhang
- University of Washington Center of Excellence in Neurobiology of Addiction, Pain, and Emotion (NAPE), Seattle, WA, USA
- University of Washington, Department of Biological Structure, Seattle, WA, USA
| | - Kasey S. Girven
- University of Washington, Department of Anesthesiology and Pain Medicine
| | - Lauren Kuo
- University of Washington Center of Excellence in Neurobiology of Addiction, Pain, and Emotion (NAPE), Seattle, WA, USA
- University of Washington Undergraduate Program in Biochemistry
- Allen Institute for Cell Science, Seattle, WA, USA
| | - Marcella M. Cline
- University of Washington Center of Excellence in Neurobiology of Addiction, Pain, and Emotion (NAPE), Seattle, WA, USA
- University of Washington, Department of Pharmacology, Seattle, WA, USA
- Cajal Neuroscience, Seattle, WA, USA
| | - Mollie X. Bernstein
- University of Washington Center of Excellence in Neurobiology of Addiction, Pain, and Emotion (NAPE), Seattle, WA, USA
- University of Washington, Department of Pharmacology, Seattle, WA, USA
| | | | - Bryce Bowler
- University of Washington, Department of Biological Structure, Seattle, WA, USA
| | - Nastacia L. Goodwin
- University of Washington Center of Excellence in Neurobiology of Addiction, Pain, and Emotion (NAPE), Seattle, WA, USA
- University of Washington, Department of Biological Structure, Seattle, WA, USA
- University of Washington, Graduate Program in Neuroscience, Seattle, WA, USA
| | - Barbara Juarez
- University of Washington Center of Excellence in Neurobiology of Addiction, Pain, and Emotion (NAPE), Seattle, WA, USA
- University of Washington, Department of Psychiatry and Behavioral Sciences, Seattle, WA, USA
- University of Washington, Department of Pharmacology, Seattle, WA, USA
- University of Maryland School of Medicine, Department of Neurobiology, Baltimore, MD, USA
| | - Larry S. Zweifel
- University of Washington Center of Excellence in Neurobiology of Addiction, Pain, and Emotion (NAPE), Seattle, WA, USA
- University of Washington, Department of Psychiatry and Behavioral Sciences, Seattle, WA, USA
- University of Washington, Department of Pharmacology, Seattle, WA, USA
| | - Sam A. Golden
- University of Washington Center of Excellence in Neurobiology of Addiction, Pain, and Emotion (NAPE), Seattle, WA, USA
- University of Washington, Department of Biological Structure, Seattle, WA, USA
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4
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Herbst A, Bexter F, Kouassi NM, Gabriel G, Rautenschlein S. Distribution of importin-α isoforms in poultry species and their tissue- and age-related differences. Res Vet Sci 2023; 164:104994. [PMID: 37696109 DOI: 10.1016/j.rvsc.2023.104994] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Revised: 08/06/2023] [Accepted: 08/15/2023] [Indexed: 09/13/2023]
Abstract
While importin-α is well studied in mammals, the knowledge in avian species is still limited. In this study, we compared the mRNA expression patterns of five importin-α isoforms in the respiratory tract, liver, and spleen of chickens, turkeys, and pekin ducks in two different age-groups. In addition, we determined the distribution of importin-α in selected tissue of conchae, trachea, and lung of post-hatch chickens at all cellular levels by immunohistochemical staining. Our results indicate that importin-α3 is the most abundant isoform in the respiratory tract of chickens, turkeys, and pekin ducks. Moreover, importin-α is expressed as a gradient with lowest mRNA levels in the conchae and highest levels in the lung. The mRNA expression levels of most isoforms were higher in tissues from post-hatch chickens and turkeys in comparison to the corresponding embryos. In contrast to that, duck embryos mostly show higher mRNA expression levels of importin-α than post-hatch ducks.
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Affiliation(s)
- Alexandra Herbst
- Clinic for Poultry, University of Veterinary Medicine Hannover, Foundation, Buenteweg 17, 30559 Hannover, Germany.
| | - Frederik Bexter
- Clinic for Poultry, University of Veterinary Medicine Hannover, Foundation, Buenteweg 17, 30559 Hannover, Germany.
| | | | - Gülsah Gabriel
- Leibniz-Institute for Virology, Martinistraße 52, 20251 Hamburg, Germany; Institute for Virology, University of Veterinary Medicine Hannover, Foundation, Buenteweg 17, 30559 Hannover, Germany.
| | - Silke Rautenschlein
- Clinic for Poultry, University of Veterinary Medicine Hannover, Foundation, Buenteweg 17, 30559 Hannover, Germany.
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5
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Karasev MM, Baloban M, Verkhusha VV, Shcherbakova DM. Nuclear Localization Signals for Optimization of Genetically Encoded Tools in Neurons. Front Cell Dev Biol 2022; 10:931237. [PMID: 35927988 PMCID: PMC9344056 DOI: 10.3389/fcell.2022.931237] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Accepted: 06/24/2022] [Indexed: 12/15/2022] Open
Abstract
Nuclear transport in neurons differs from that in non-neuronal cells. Here we developed a non-opsin optogenetic tool (OT) for the nuclear export of a protein of interest induced by near-infrared (NIR) light. In darkness, nuclear import reverses the OT action. We used this tool for comparative analysis of nuclear transport dynamics mediated by nuclear localization signals (NLSs) with different importin specificities. We found that widely used KPNA2-binding NLSs, such as Myc and SV40, are suboptimal in neurons. We identified uncommon NLSs mediating fast nuclear import and demonstrated that the performance of the OT for nuclear export can be adjusted by varying NLSs. Using these NLSs, we optimized the NIR OT for light-controlled gene expression for lower background and higher contrast in neurons. The selected NLSs binding importins abundant in neurons could improve performance of genetically encoded tools in these cells, including OTs and gene-editing tools.
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Affiliation(s)
- Maksim M. Karasev
- Medicum, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Mikhail Baloban
- Department of Genetics and Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, NY, United States
| | - Vladislav V. Verkhusha
- Medicum, Faculty of Medicine, University of Helsinki, Helsinki, Finland
- Department of Genetics and Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, NY, United States
| | - Daria M. Shcherbakova
- Department of Genetics and Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, NY, United States
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6
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The intricate roles of RCC1 in normal cells and cancer cells. Biochem Soc Trans 2022; 50:83-93. [PMID: 35191966 DOI: 10.1042/bst20210861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Revised: 01/24/2022] [Accepted: 02/02/2022] [Indexed: 11/17/2022]
Abstract
RCC1 (regulator of chromosome condensation 1) is a highly conserved chromatin-binding protein and the only known guanine-nucleotide exchange factor of Ran (a nuclear Ras homolog). RCC1 plays an essential role in the regulation of cell cycle-related activities such as nuclear envelope formation, nuclear pore complex and spindle assembly, and nucleocytoplasmic transport. Over the last decade, increasing evidence has emerged highlighting the potential relevance of RCC1 to carcinogenesis, especially cervical, lung, and breast cancer. In this review, we briefly discuss the roles of RCC1 in both normal and tumor cells based on articles published in recent years, followed by a brief overview of future perspectives in the field.
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7
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Jibiki K, Kodama TS, Suenaga A, Kawase Y, Shibazaki N, Nomoto S, Nagasawa S, Nagashima M, Shimodan S, Kikuchi R, Okayasu M, Takashita R, Mehmood R, Saitoh N, Yoneda Y, Akagi KI, Yasuhara N. Importin α2 association with chromatin: Direct DNA binding via a novel DNA-binding domain. Genes Cells 2021; 26:945-966. [PMID: 34519142 DOI: 10.1111/gtc.12896] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Revised: 09/10/2021] [Accepted: 09/11/2021] [Indexed: 12/18/2022]
Abstract
The nuclear transport of proteins is important for facilitating appropriate nuclear functions. The importin α family proteins play key roles in nuclear transport as transport receptors for copious nuclear proteins. Additionally, these proteins possess other functions, including chromatin association and gene regulation. However, these nontransport functions of importin α are not yet fully understood, especially their molecular-level mechanisms and consequences for functioning with chromatin. Here, we report the novel molecular characteristics of importin α binding to diverse DNA sequences in chromatin. We newly identified and characterized a DNA-binding domain-the Nucleic Acid Associating Trolley pole domain (NAAT domain)-in the N-terminal region of importin α within the conventional importin β binding (IBB) domain that is necessary for nuclear transport of cargo proteins. Furthermore, we found that the DNA binding of importin α synergistically coupled the recruitment of its cargo protein to DNA. This is the first study to delineate the interaction between importin α and chromatin DNA via the NAAT domain, indicating the bifunctionality of the importin α N-terminal region for nuclear transport and chromatin association.
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Affiliation(s)
- Kazuya Jibiki
- Graduate School of Integrated Basic Sciences, Nihon University, Tokyo, Japan
| | - Takashi S Kodama
- National Institutes of Biomedical Innovation, Health and Nutrition (NIBIOHN), Osaka, Japan
| | - Atsushi Suenaga
- Graduate School of Integrated Basic Sciences, Nihon University, Tokyo, Japan.,Department of Biosciences, College of Humanities and Sciences, Nihon University, Tokyo, Japan
| | - Yota Kawase
- Graduate School of Integrated Basic Sciences, Nihon University, Tokyo, Japan
| | - Noriko Shibazaki
- Department of Biosciences, College of Humanities and Sciences, Nihon University, Tokyo, Japan
| | - Shin Nomoto
- Graduate School of Integrated Basic Sciences, Nihon University, Tokyo, Japan
| | - Seiya Nagasawa
- Department of Biosciences, College of Humanities and Sciences, Nihon University, Tokyo, Japan
| | - Misaki Nagashima
- Department of Biosciences, College of Humanities and Sciences, Nihon University, Tokyo, Japan
| | - Shieri Shimodan
- Department of Biosciences, College of Humanities and Sciences, Nihon University, Tokyo, Japan
| | - Renan Kikuchi
- Department of Biosciences, College of Humanities and Sciences, Nihon University, Tokyo, Japan
| | - Mina Okayasu
- Department of Biosciences, College of Humanities and Sciences, Nihon University, Tokyo, Japan
| | - Ruka Takashita
- Department of Biosciences, College of Humanities and Sciences, Nihon University, Tokyo, Japan
| | - Rashid Mehmood
- Department of Life Sciences, College of Science and General Studies, Alfaisal University, Riyadh, Saudi Arabia
| | - Noriko Saitoh
- Division of Cancer Biology, The Cancer Institute of JFCR, Tokyo, Japan
| | - Yoshihiro Yoneda
- National Institutes of Biomedical Innovation, Health and Nutrition (NIBIOHN), Osaka, Japan
| | - Ken-Ichi Akagi
- National Institutes of Biomedical Innovation, Health and Nutrition (NIBIOHN), Osaka, Japan.,Environmental Metabolic Analysis Research Team, RIKEN Center for Sustainable Resource Science, Yokohama, Japan
| | - Noriko Yasuhara
- Graduate School of Integrated Basic Sciences, Nihon University, Tokyo, Japan.,Department of Biosciences, College of Humanities and Sciences, Nihon University, Tokyo, Japan
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8
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Kalita J, Kapinos LE, Lim RYH. On the asymmetric partitioning of nucleocytoplasmic transport - recent insights and open questions. J Cell Sci 2021; 134:239102. [PMID: 33912945 DOI: 10.1242/jcs.240382] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Macromolecular cargoes are asymmetrically partitioned in the nucleus or cytoplasm by nucleocytoplasmic transport (NCT). At the center of this activity lies the nuclear pore complex (NPC), through which soluble factors circulate to orchestrate NCT. These include cargo-carrying importin and exportin receptors from the β-karyopherin (Kapβ) family and the small GTPase Ran, which switches between guanosine triphosphate (GTP)- and guanosine diphosphate (GDP)-bound forms to regulate cargo delivery and compartmentalization. Ongoing efforts have shed considerable light on how these soluble factors traverse the NPC permeability barrier to sustain NCT. However, this does not explain how importins and exportins are partitioned in the cytoplasm and nucleus, respectively, nor how a steep RanGTP-RanGDP gradient is maintained across the nuclear envelope. In this Review, we peel away the multiple layers of control that regulate NCT and juxtapose unresolved features against known aspects of NPC function. Finally, we discuss how NPCs might function synergistically with Kapβs, cargoes and Ran to establish the asymmetry of NCT.
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Affiliation(s)
- Joanna Kalita
- Biozentrum and the Swiss Nanoscience Institute, University of Basel, Basel CH4056, Switzerland
| | - Larisa E Kapinos
- Biozentrum and the Swiss Nanoscience Institute, University of Basel, Basel CH4056, Switzerland
| | - Roderick Y H Lim
- Biozentrum and the Swiss Nanoscience Institute, University of Basel, Basel CH4056, Switzerland
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9
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Miyamoto Y, Sasaki M, Miyata H, Monobe Y, Nagai M, Otani M, Whiley PAF, Morohoshi A, Oki S, Matsuda J, Akagi KI, Adachi J, Okabe M, Ikawa M, Yoneda Y, Loveland KL, Oka M. Genetic loss of importin α4 causes abnormal sperm morphology and impacts on male fertility in mouse. FASEB J 2020; 34:16224-16242. [PMID: 33058343 DOI: 10.1096/fj.202000768rr] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 09/27/2020] [Accepted: 09/29/2020] [Indexed: 11/11/2022]
Abstract
Importin α proteins play a central role in the transport of cargo from the cytoplasm to the nucleus. In this study, we observed that male knock-out mice for importin α4, which is encoded by the Kpna4 gene (Kpna4-/- ), were subfertile and yielded smaller litter sizes than those of wild-type (WT) males. In contrast, mice lacking the closely related importin α3 (Kpna3-/- ) were fertile. In vitro fertilization and sperm motility assays demonstrated that sperm from Kpna4-/- mice had significantly reduced quality and motility. In addition, acrosome reaction was also impaired in Kpna4-/- mice. Transmission electron microscopy revealed striking defects, including abnormal head morphology and multiple axoneme structures in the flagella of Kpna4-/- mice. A five-fold increase in the frequency of abnormalities in Kpna4-/- mice compared to WT mice indicates the functional importance of importin α4 in normal sperm development. Moreover, Nesprin-2, which is a component of the linker of nucleus and cytoskeleton complex, was expressed at lower levels in sperm from Kpna4-/- mice and was localized with abnormal axonemes, suggesting incorrect formation of the nuclear membrane-cytoskeleton structure during spermiogenesis. Proteomics analysis of Kpna4-/- testis showed significantly altered expression of proteins related to sperm formation, which provided evidence that genetic loss of importin α4 perturbed chromatin status. Collectively, these findings indicate that importin α4 is critical for establishing normal sperm morphology in mice, providing new insights into male germ cell development by highlighting the requirement of importin α4 for normal fertility.
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Affiliation(s)
- Yoichi Miyamoto
- Laboratory of Nuclear Transport Dynamics, National Institutes of Biomedical Innovation, Health and Nutrition (NIBIOHN), Osaka, Japan
| | - Mitsuho Sasaki
- Laboratory of Animal Models for Human Diseases, National Institutes of Biomedical Innovation, Health and Nutrition (NIBIOHN), Osaka, Japan
| | - Haruhiko Miyata
- Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
| | - Yoko Monobe
- Section of Laboratory Equipment, National Institutes of Biomedical Innovation, Health and Nutrition (NIBIOHN), Osaka, Japan
| | - Masahiro Nagai
- Department of Frontier Bioscience, Graduate School of Frontier Bioscience, Osaka University, Osaka, Japan
| | - Mayumi Otani
- Laboratory of Nuclear Transport Dynamics, National Institutes of Biomedical Innovation, Health and Nutrition (NIBIOHN), Osaka, Japan
| | - Penny A F Whiley
- Centre for Reproductive Health, Hudson Institute of Medical Research, Clayton, VIC, Australia
| | - Akane Morohoshi
- Research Institute for Microbial Diseases, Osaka University, Osaka, Japan.,Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Shinya Oki
- Department of Drug Discovery Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Junichiro Matsuda
- Laboratory of Animal Models for Human Diseases, National Institutes of Biomedical Innovation, Health and Nutrition (NIBIOHN), Osaka, Japan
| | - Ken-Ichi Akagi
- Section of Laboratory Equipment, National Institutes of Biomedical Innovation, Health and Nutrition (NIBIOHN), Osaka, Japan
| | - Jun Adachi
- Laboratory of Proteome Research, National Institutes of Biomedical Innovation, Health and Nutrition (NIBIOHN), Osaka, Japan
| | - Masaru Okabe
- Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
| | - Masahito Ikawa
- Research Institute for Microbial Diseases, Osaka University, Osaka, Japan.,Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Yoshihiro Yoneda
- National Institutes of Biomedical Innovation, Health and Nutrition (NIBIOHN), Osaka, Japan
| | - Kate L Loveland
- Centre for Reproductive Health, Hudson Institute of Medical Research, Clayton, VIC, Australia.,Department of Molecular and Translational Sciences, School of Clinical Sciences, Monash University, Clayton, VIC, Australia
| | - Masahiro Oka
- Laboratory of Nuclear Transport Dynamics, National Institutes of Biomedical Innovation, Health and Nutrition (NIBIOHN), Osaka, Japan
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10
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Marvaldi L, Panayotis N, Alber S, Dagan SY, Okladnikov N, Koppel I, Di Pizio A, Song DA, Tzur Y, Terenzio M, Rishal I, Gordon D, Rother F, Hartmann E, Bader M, Fainzilber M. Importin α3 regulates chronic pain pathways in peripheral sensory
neurons. Science 2020; 369:842-846. [DOI: 10.1126/science.aaz5875] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2019] [Revised: 05/26/2020] [Accepted: 06/30/2020] [Indexed: 12/13/2022]
Abstract
How is neuropathic pain regulated in peripheral sensory neurons?
Importins are key regulators of nucleocytoplasmic transport. In this study,
we found that importin α3 (also known as karyopherin subunit alpha 4) can
control pain responsiveness in peripheral sensory neurons in mice. Importin
α3 knockout or sensory neuron–specific knockdown in mice reduced
responsiveness to diverse noxious stimuli and increased tolerance to
neuropathic pain. Importin α3–bound c-Fos and importin α3–deficient neurons
were impaired in c-Fos nuclear import. Knockdown or dominant-negative
inhibition of c-Fos or c-Jun in sensory neurons reduced neuropathic pain. In
silico screens identified drugs that mimic importin α3 deficiency. These
drugs attenuated neuropathic pain and reduced c-Fos nuclear localization.
Thus, perturbing c-Fos nuclear import by importin α3 in peripheral neurons
can promote analgesia.
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Affiliation(s)
- Letizia Marvaldi
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Nicolas Panayotis
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Stefanie Alber
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Shachar Y. Dagan
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Nataliya Okladnikov
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Indrek Koppel
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Agostina Di Pizio
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Didi-Andreas Song
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Yarden Tzur
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Marco Terenzio
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
- Molecular Neuroscience Unit, Okinawa Institute of Science and Technology, Kunigami-gun, Okinawa 904-0412, Japan
| | - Ida Rishal
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Dalia Gordon
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Franziska Rother
- Max Delbrück Center for Molecular Medicine, 13125 Berlin, Germany
- Center for Structural and Cellular Biology in Medicine, Institute of Biology, University of Lübeck, 23538 Lübeck, Germany
| | - Enno Hartmann
- Center for Structural and Cellular Biology in Medicine, Institute of Biology, University of Lübeck, 23538 Lübeck, Germany
| | - Michael Bader
- Max Delbrück Center for Molecular Medicine, 13125 Berlin, Germany
- Center for Structural and Cellular Biology in Medicine, Institute of Biology, University of Lübeck, 23538 Lübeck, Germany
- Charité – Universitätsmedizin Berlin, 10117 Berlin, Germany
| | - Mike Fainzilber
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
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11
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Differential Behaviours and Preferential Bindings of Influenza Nucleoproteins on Importins-α. Viruses 2020; 12:v12080834. [PMID: 32751671 PMCID: PMC7472415 DOI: 10.3390/v12080834] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Revised: 07/23/2020] [Accepted: 07/27/2020] [Indexed: 12/20/2022] Open
Abstract
Influenza viruses are negative single-stranded RNA viruses with nuclear transcription and replication. They enter the nucleus by using the cellular importin-α/-β nuclear import machinery. Influenza nucleoproteins from influenza A, B, C and D viruses possess a nuclear localization signal (NLS) localized on an intrinsically disordered extremity (NPTAIL). In this paper, using size exclusion chromatography (SEC), SEC-multi-angle laser light scattering (SEC-MALLS) analysis, surface plasmon resonance (SPR) and fluorescence anisotropy, we provide the first comparative study designed to dissect the interaction between the four NPTAILs and four importins-α identified as partners. All interactions between NPTAILs and importins-α have high association and dissociation rates and present a distinct and specific behaviour. D/NPTAIL interacts strongly with all importins-α while B/NPTAIL shows weak affinity for importins-α. A/NPTAIL and C/NPTAIL present preferential importin-α partners. Mutations in B/NPTAIL and D/NPTAIL show a loss of importin-α binding, confirming key NLS residues. Taken together, our results provide essential highlights of this complex translocation mechanism.
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12
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Zhou Y, Liu F, Xu Q, Yang B, Li X, Jiang S, Hu L, Zhang X, Zhu L, Li Q, Zhu X, Shao H, Dai M, Shen Y, Ni B, Wang S, Zhang Z, Teng Y. Inhibiting Importin 4-mediated nuclear import of CEBPD enhances chemosensitivity by repression of PRKDC-driven DNA damage repair in cervical cancer. Oncogene 2020; 39:5633-5648. [PMID: 32661323 PMCID: PMC7441007 DOI: 10.1038/s41388-020-1384-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 06/10/2020] [Accepted: 06/29/2020] [Indexed: 12/24/2022]
Abstract
Cervical cancer (CC) remains highest in the mortality of female reproductive system cancers, while cisplatin (CDDP) resistance is the one of main reasons for the lethality. Preceding evidence has supported that karyopherins are associated with chemoresistance. In this study, we simultaneously compared CDDP-incomplete responders with CDDP-complete responders of CC patients and CDDP‐insensitive CC cell lines with CDDP‐sensitive group. We finally identified that DNA-PKcs (PRKDC) was related to CDDP sensitivity after overlapping in CC sample tissues and CC cell lines. Further functional assay revealed that targeting PRKDC by shRNA and NU7026 (specific PRKDC inhibitor) could enhance CDDP sensitivity in vitro and in vivo, which was mediated by impairing DNA damage repair pathway in CC. Mechanistically, we found that PRKDC was transcriptionally upregulated by CCAAT/enhancer-binding protein delta (CEBPD), while intriguingly, CDDP treatment strengthened the transcriptional activity of CEBPD to PRKDC. We further disclosed that Importin 4 (IPO4) augmented the nuclear translocation of CEBPD through nuclear localization signals (NLS) to activate PRKDC-mediated DNA damage repair in response to CDDP. Moreover, we demonstrated that IPO4 and CEBPD knockdown improved CDDP-induced cytotoxicity in vitro and in vivo. Together, we shed the novel insight into the role of IPO4 in chemosensitivity and provide a clinical translational potential to enhance CC chemosensitivity since the IPO4-CEBPD-PRKDC axis is actionable via NU7026 (PRKDC inhibitor) or targeting IPO4 in combination with CDDP.
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Affiliation(s)
- Yang Zhou
- Department of Gynecology and Obstetrics, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, 600 Yishan Road, Shanghai, 200233, PR China.,Department of Gynecology and Obstetrics, Shanghai Eighth People's Hospital, Affiliated to Jiangsu University, Shanghai, 200233, PR China
| | - Fei Liu
- Department of Gynecology and Obstetrics, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, 600 Yishan Road, Shanghai, 200233, PR China.,Global Clinical Medical Affairs (GCMA), Shanghai Henlius Biotech, Inc. 7/F, Innov Tower, Zone A, No.1801 HongMei Rd. Xuhui District, Shanghai, 200233, PR China
| | - Qinyang Xu
- Department of Gynecology and Obstetrics, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, 600 Yishan Road, Shanghai, 200233, PR China
| | - Bikang Yang
- Department of Gynecology and Obstetrics, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, 600 Yishan Road, Shanghai, 200233, PR China
| | - Xiao Li
- Department of Gynecology and Obstetrics, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, 600 Yishan Road, Shanghai, 200233, PR China
| | - Shuheng Jiang
- State Key Laboratory for Oncogenes and Related Genes, Shanghai Cancer Institute, Shanghai Jiao Tong University, Shanghai, PR China
| | - Lipeng Hu
- State Key Laboratory for Oncogenes and Related Genes, Shanghai Cancer Institute, Shanghai Jiao Tong University, Shanghai, PR China
| | - Xueli Zhang
- State Key Laboratory for Oncogenes and Related Genes, Shanghai Cancer Institute, Shanghai Jiao Tong University, Shanghai, PR China
| | - Lili Zhu
- State Key Laboratory for Oncogenes and Related Genes, Shanghai Cancer Institute, Shanghai Jiao Tong University, Shanghai, PR China
| | - Qing Li
- State Key Laboratory for Oncogenes and Related Genes, Shanghai Cancer Institute, Shanghai Jiao Tong University, Shanghai, PR China
| | - Xiaolu Zhu
- Department of Gynecology and Obstetrics, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, 600 Yishan Road, Shanghai, 200233, PR China
| | - Hongfang Shao
- Center of Reproductive Medicine, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, 600 Yishan Road, Shanghai, 200233, PR China
| | - Miao Dai
- Department of Gynecologic Oncology, Hunan Cancer Hospital, The Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, PR China
| | - Yifei Shen
- Department of Orthopedics, Shanghai East Hospital, School of Medicine, Shanghai Tongji University, Shanghai, 200120, PR China
| | - Bo Ni
- Department of Gastrointestinal Surgery, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, 200217, PR China
| | - Shuai Wang
- Jacobi medical center, bronx, New York, NY, 10461, USA
| | - Zhigang Zhang
- State Key Laboratory for Oncogenes and Related Genes, Shanghai Cancer Institute, Shanghai Jiao Tong University, Shanghai, PR China.
| | - Yincheng Teng
- Department of Gynecology and Obstetrics, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, 600 Yishan Road, Shanghai, 200233, PR China. .,Department of Gynecology and Obstetrics, Shanghai Eighth People's Hospital, Affiliated to Jiangsu University, Shanghai, 200233, PR China.
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13
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Jamal-Livani N, Mohammadian E, Sheikh Arabi M, Safdari Y. Protein-based drug carrier specific for HER2-positive breast cancer cells. J Drug Deliv Sci Technol 2020. [DOI: 10.1016/j.jddst.2020.101623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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14
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Thiele S, Stanelle-Bertram S, Beck S, Kouassi NM, Zickler M, Müller M, Tuku B, Resa-Infante P, van Riel D, Alawi M, Günther T, Rother F, Hügel S, Reimering S, McHardy A, Grundhoff A, Brune W, Osterhaus A, Bader M, Hartmann E, Gabriel G. Cellular Importin-α3 Expression Dynamics in the Lung Regulate Antiviral Response Pathways against Influenza A Virus Infection. Cell Rep 2020; 31:107549. [PMID: 32320654 PMCID: PMC7172908 DOI: 10.1016/j.celrep.2020.107549] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 02/04/2020] [Accepted: 03/31/2020] [Indexed: 01/09/2023] Open
Abstract
Importin-α adaptor proteins orchestrate dynamic nuclear transport processes involved in cellular homeostasis. Here, we show that importin-α3, one of the main NF-κB transporters, is the most abundantly expressed classical nuclear transport factor in the mammalian respiratory tract. Importin-α3 promoter activity is regulated by TNF-α-induced NF-κB in a concentration-dependent manner. High-level TNF-α-inducing highly pathogenic avian influenza A viruses (HPAIVs) isolated from fatal human cases harboring human-type polymerase signatures (PB2 627K, 701N) significantly downregulate importin-α3 mRNA expression in primary lung cells. Importin-α3 depletion is restored upon back-mutating the HPAIV polymerase into an avian-type signature (PB2 627E, 701D) that can no longer induce high TNF-α levels. Importin-α3-deficient mice show reduced NF-κB-activated antiviral gene expression and increased influenza lethality. Thus, importin-α3 plays a key role in antiviral immunity against influenza. Lifting the bottleneck in importin-α3 availability in the lung might provide a new strategy to combat respiratory virus infections.
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Affiliation(s)
- Swantje Thiele
- Viral Zoonosis - One Health, Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
| | - Stephanie Stanelle-Bertram
- Viral Zoonosis - One Health, Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
| | - Sebastian Beck
- Viral Zoonosis - One Health, Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
| | - Nancy Mounogou Kouassi
- Viral Zoonosis - One Health, Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
| | - Martin Zickler
- Viral Zoonosis - One Health, Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
| | - Martin Müller
- Viral Zoonosis - One Health, Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
| | - Berfin Tuku
- Viral Zoonosis - One Health, Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
| | - Patricia Resa-Infante
- Viral Zoonosis - One Health, Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
| | - Debby van Riel
- Viral Zoonosis - One Health, Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany; Department of Viroscience, Erasmus Medical Center, Rotterdam, the Netherlands
| | - Malik Alawi
- Bioinformatics Service Facility, University Medical Center Hamburg-Eppendorf, Hamburg, Germany; Virus Genomics, Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
| | - Thomas Günther
- Virus Genomics, Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
| | - Franziska Rother
- Molecular Biology of Peptide Hormones, Max Delbrück Center for Molecular Medicine, Berlin, Germany; Institute for Biology, Center for Structural and Cellular Biology in Medicine, University of Lübeck, Lübeck, Germany
| | - Stefanie Hügel
- Molecular Biology of Peptide Hormones, Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Susanne Reimering
- Computational Biology of Infection Research, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Alice McHardy
- Computational Biology of Infection Research, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Adam Grundhoff
- Virus Genomics, Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
| | - Wolfram Brune
- Virus-Host Interaction, Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
| | - Albert Osterhaus
- Research Center for Emerging Infections and Zoonoses, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Michael Bader
- Molecular Biology of Peptide Hormones, Max Delbrück Center for Molecular Medicine, Berlin, Germany; Institute for Biology, Center for Structural and Cellular Biology in Medicine, University of Lübeck, Lübeck, Germany; Charité-Universitätsmedizin, Berlin, Germany
| | - Enno Hartmann
- Institute for Biology, Center for Structural and Cellular Biology in Medicine, University of Lübeck, Lübeck, Germany
| | - Gülsah Gabriel
- Viral Zoonosis - One Health, Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany; Institute of Virology, University of Veterinary Medicine, Hannover, Germany.
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15
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Radhakrishnan K, Park SJ, Kim SW, Hariharasudhan G, Jeong SY, Chang IY, Lee JH. Karyopherin α-2 Mediates MDC1 Nuclear Import through a Functional Nuclear Localization Signal in the tBRCT Domain of MDC1. Int J Mol Sci 2020; 21:ijms21072650. [PMID: 32290222 PMCID: PMC7177644 DOI: 10.3390/ijms21072650] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Revised: 04/06/2020] [Accepted: 04/08/2020] [Indexed: 12/15/2022] Open
Abstract
Mediator of DNA damage checkpoint protein 1 (MDC1) plays a vital role in DNA damage response (DDR) by coordinating the repair of double strand breaks (DSBs). Here, we identified a novel interaction between MDC1 and karyopherin α-2 (KPNA2), a nucleocytoplasmic transport adaptor, and showed that KPNA2 is necessary for MDC1 nuclear import. Thereafter, we identified a functional nuclear localization signal (NLS) between amino acid residues 1989–1994 of the two Breast Cancer 1 (BRCA1) carboxyl-terminal (tBRCT) domain of MDC1 and demonstrated disruption of this NLS impaired interaction between MDC1 and KPNA2 and reduced nuclear localization of MDC1. In KPNA2-depleted cells, the recruitment of MDC1, along with the downstream signaling p roteins Ring Finger Protein 8 (RNF8), 53BP1-binding protein 1 (53BP1), BRCA1, and Ring Finger Protein 168 (RNF168), to DNA damage sites was abolished. Additionally, KPNA2-depleted cells had a decreased rate of homologous recombination (HR) repair. Our data suggest that KPNA2-mediated MDC1 nuclear import is important for DDR signaling and DSB repair.
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Affiliation(s)
- Kamalakannan Radhakrishnan
- Laboratory of Genomic Instability and Cancer therapeutics, Cancer Mutation Research Center, Chosun University, Gwangju 61452, Korea; (K.R.); (S.-J.P.); (S.W.K.); (G.H.); (S.-Y.J.)
| | - Seon-Joo Park
- Laboratory of Genomic Instability and Cancer therapeutics, Cancer Mutation Research Center, Chosun University, Gwangju 61452, Korea; (K.R.); (S.-J.P.); (S.W.K.); (G.H.); (S.-Y.J.)
- Department of Premedical Sciences, College of Medicine, Chosun University, Gwangju 61452, Korea
| | - Seok Won Kim
- Laboratory of Genomic Instability and Cancer therapeutics, Cancer Mutation Research Center, Chosun University, Gwangju 61452, Korea; (K.R.); (S.-J.P.); (S.W.K.); (G.H.); (S.-Y.J.)
- Department of Neurosurgery, College of Medicine, Chosun University, Gwangju 61452, Korea
| | - Gurusamy Hariharasudhan
- Laboratory of Genomic Instability and Cancer therapeutics, Cancer Mutation Research Center, Chosun University, Gwangju 61452, Korea; (K.R.); (S.-J.P.); (S.W.K.); (G.H.); (S.-Y.J.)
| | - Seo-Yeon Jeong
- Laboratory of Genomic Instability and Cancer therapeutics, Cancer Mutation Research Center, Chosun University, Gwangju 61452, Korea; (K.R.); (S.-J.P.); (S.W.K.); (G.H.); (S.-Y.J.)
- Department of Cellular and Molecular Medicine, College of Medicine, Chosun University, Gwangju 61452, Korea
| | - In Youb Chang
- Department of Anatomy, College of Medicine, Chosun University, Gwangju 61452, Korea;
| | - Jung-Hee Lee
- Laboratory of Genomic Instability and Cancer therapeutics, Cancer Mutation Research Center, Chosun University, Gwangju 61452, Korea; (K.R.); (S.-J.P.); (S.W.K.); (G.H.); (S.-Y.J.)
- Department of Cellular and Molecular Medicine, College of Medicine, Chosun University, Gwangju 61452, Korea
- Correspondence: ; Tel.: +82-62-230-7469; Fax: +82-62-230-6586
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16
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Importin α5 Regulates Anxiety through MeCP2 and Sphingosine Kinase 1. Cell Rep 2019; 25:3169-3179.e7. [PMID: 30540948 PMCID: PMC6302549 DOI: 10.1016/j.celrep.2018.11.066] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Revised: 10/09/2018] [Accepted: 11/15/2018] [Indexed: 01/08/2023] Open
Abstract
Importins mediate transport from synapse to soma and from cytoplasm to nucleus, suggesting that perturbation of importin-dependent pathways should have significant neuronal consequences. A behavioral screen on five importin α knockout lines revealed that reduced expression of importin α5 (KPNA1) in hippocampal neurons specifically decreases anxiety in mice. Re-expression of importin α5 in ventral hippocampus of knockout animals increased anxiety behaviors to wild-type levels. Hippocampal neurons lacking importin α5 reveal changes in presynaptic plasticity and modified expression of MeCP2-regulated genes, including sphingosine kinase 1 (Sphk1). Knockout of importin α5, but not importin α3 or α4, reduces MeCP2 nuclear localization in hippocampal neurons. A Sphk1 blocker reverses anxiolysis in the importin α5 knockout mouse, while pharmacological activation of sphingosine signaling has robust anxiolytic effects in wild-type animals. Thus, importin α5 influences sphingosine-sensitive anxiety pathways by regulating MeCP2 nuclear import in hippocampal neurons. Reduced expression of importin α5 in hippocampal neurons decreases anxiety Importin α5 is required for nuclear localization of MeCP2 in hippocampal neurons Importin α5 knockout increases expression of Sphk1, an MeCP2-regulated gene Pharmacological modulation of Sphk1 and the S1P receptor affects anxiety
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17
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Zhang W, Lu Y, Li X, Zhang J, Lin W, Zhang W, Zheng L, Li X. IPO5 promotes the proliferation and tumourigenicity of colorectal cancer cells by mediating RASAL2 nuclear transportation. JOURNAL OF EXPERIMENTAL & CLINICAL CANCER RESEARCH : CR 2019; 38:296. [PMID: 31288861 PMCID: PMC6617704 DOI: 10.1186/s13046-019-1290-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Accepted: 06/25/2019] [Indexed: 12/17/2022]
Abstract
Background Karyopherin nuclear transport receptors play important roles in tumour development and drug resistance and have been reported as potential biomarkers and therapeutic targets for tumour treatment. However, IPO5, one of the karyopherin nuclear transport receptor family members, remains largely uncharacterized in tumour progression. Methods The TCGA data, quantitative reverse transcription-PCR (qRT-PCR), western blotting, and IHC analyses were used to detect IPO5 expression in CRC tissues. A series of in vivo and in vitro experiments was utilized to demonstrate the function of IPO5 in CRC tissues. Mass spectrometry (MS), CO-IP technology, subcellular fractionation, and immunofluorescence were utilized to investigate the possible mechanisms of CRC. Results IPO5 was highly expressed and positively correlated with the clinicopathological characteristics of colorectal cancer tissues. Functional experiments indicated that IPO5 could promote the development of CRC. Mechanistically, we screened RASAL2, one cargo of IPO5, and further confirmed that IPO5 bound to the NLS sequence of RASAL2, mediating RASAL2 nuclear translocation and inducing RAS signal activation, thereby promoting the progression of CRC. Conclusions Together, our results indicate that IPO5 is overexpressed in colorectal cancer cells. By transporting RASAL2, IPO5 may play a crucial role in CRC. Electronic supplementary material The online version of this article (10.1186/s13046-019-1290-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Wenjuan Zhang
- Department of Pathology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515, People's Republic of China
| | - Yanxia Lu
- Department of Pathology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515, People's Republic of China
| | - Xiaomin Li
- Department of Pathology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515, People's Republic of China
| | - Jianming Zhang
- Department of Pathology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515, People's Republic of China.,Department of General Surgery, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Weihao Lin
- Department of Pathology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515, People's Republic of China
| | - Wei Zhang
- Department of Pathology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515, People's Republic of China
| | - Lin Zheng
- Department of Pathology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515, People's Republic of China
| | - Xuenong Li
- Department of Pathology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515, People's Republic of China.
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18
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Resa-Infante P, Bonet J, Thiele S, Alawi M, Stanelle-Bertram S, Tuku B, Beck S, Oliva B, Gabriel G. Alternative interaction sites in the influenza A virus nucleoprotein mediate viral escape from the importin-α7 mediated nuclear import pathway. FEBS J 2019; 286:3374-3388. [PMID: 31044563 DOI: 10.1111/febs.14868] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 03/20/2019] [Accepted: 04/29/2019] [Indexed: 01/01/2023]
Abstract
Influenza A viruses are able to adapt to restrictive conditions due to their high mutation rates. Importin-α7 is a component of the nuclear import machinery required for avian-mammalian adaptation and replicative fitness in human cells. Here, we elucidate the mechanisms by which influenza A viruses may escape replicative restriction in the absence of importin-α7. To address this question, we assessed viral evolution in mice lacking the importin-α7 gene. We show that three mutations in particular occur with high frequency in the viral nucleoprotein (NP) protein (G102R, M105K and D375N) in a specific structural area upon in vivo adaptation. Moreover, our findings suggest that the adaptive NP mutations mediate viral escape from importin-α7 requirement likely due to the utilization of alternative interaction sites in NP beyond the classical nuclear localization signal. However, viral escape from importin-α7 by mutations in NP is, at least in part, associated with reduced viral replication highlighting the crucial contribution of importin-α7 to replicative fitness in human cells.
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Affiliation(s)
- Patricia Resa-Infante
- Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
| | - Jaume Bonet
- Structural Bioinformatics Lab (GRIB), Barcelona Research Park of Biomedicine (PRBB), Universitat Pompeu Fabra, Barcelona, Spain
| | - Swantje Thiele
- Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
| | - Malik Alawi
- Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany.,Bioinformatics Core, University Medical Center Hamburg-Eppendorf, Germany
| | | | - Berfin Tuku
- Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
| | - Sebastian Beck
- Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
| | - Baldo Oliva
- Structural Bioinformatics Lab (GRIB), Barcelona Research Park of Biomedicine (PRBB), Universitat Pompeu Fabra, Barcelona, Spain
| | - Gülsah Gabriel
- Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany.,Institute of Virology, University of Veterinary Medicine Hannover, Hamburg, Germany
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19
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Kassianidou E, Kalita J, Lim RYH. The role of nucleocytoplasmic transport in mechanotransduction. Exp Cell Res 2019; 377:86-93. [PMID: 30768931 DOI: 10.1016/j.yexcr.2019.02.009] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 02/10/2019] [Accepted: 02/12/2019] [Indexed: 12/12/2022]
Abstract
Cells integrate mechanical and biochemical signals via a process called mechanotransduction to generate essential gene expression patterns in space and time. This is vital for cell migration and proliferation as well as tissue morphogenesis and remodeling. While the force-sensing and force-transducing mechanisms are generally known, it remains unclear how mechanoresponsive transcription factors (TFs) are selectively translocated into the nucleus upon force activation. Such TFs include Yes-Associated Protein (YAP), Myocardin Related Transcription Factors (MRTFs), Hypoxia Induced Factors (HIFs) and others. Here, we discuss how the nucleocytoplasmic transport machinery intersects with mechanoresponsive TFs to facilitate their selective transport through nuclear pore complexes.
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Affiliation(s)
- Elena Kassianidou
- Biozentrum and the Swiss Nanoscience Institute, University of Basel, Klingelbergstrasse 70, CH-4056 Basel, Switzerland
| | - Joanna Kalita
- Biozentrum and the Swiss Nanoscience Institute, University of Basel, Klingelbergstrasse 70, CH-4056 Basel, Switzerland
| | - Roderick Y H Lim
- Biozentrum and the Swiss Nanoscience Institute, University of Basel, Klingelbergstrasse 70, CH-4056 Basel, Switzerland.
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20
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Identification of a novel bipartite nuclear localization signal in the DNA polymerase of the betabaculovirus Pieris rapae granulovirus. Arch Virol 2018; 164:839-845. [PMID: 30506470 DOI: 10.1007/s00705-018-4115-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Accepted: 10/15/2018] [Indexed: 10/27/2022]
Abstract
DNA polymerase (DNApol) is highly conserved in all baculoviruses and plays an essential role in viral DNA replication. Previous results showed that the DNApol of the betabaculovirus Pieris rapae granulovirus (PiraGV) can localize in the nucleus. However, it is not clear how the DNApol is transported into the nucleus. Bioinformatic and GFP localization analysis showed that PiraGV DNApol contains a nuclear localization signal (NLS) at aa 4-25 (LFKRKLDEPPTDHTLVKAIKLS) of the N-terminus that does not match either the classical monopartite or the bipartite NLS consensus sequence. Multiple-point-substitution analysis confirmed that the NLS is required for transport of PiraGV DNApol into the nucleus. We also substituted the NLS of the PiraGV DNApol for that of the alphabaculovirus Spodoptera litura nuclear polyhedrosis virus (SpltNPV) DNApol. A viral growth curve and quantitative real-time PCR revealed that the substitution impaired viral DNA replication and resulted in a reduction in virus production. Together, our results show that PiraGV contains a novel NLS and that the NLS cannot efficiently replace that of SpltNPV DNApol for viral DNA synthesis and virus production.
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Tazat K, Schindler S, Depping R, Mabjeesh NJ. Septin 9 isoform 1 (SEPT9_i1) specifically interacts with importin-α7 to drive hypoxia-inducible factor (HIF)-1α nuclear translocation. Cytoskeleton (Hoboken) 2018; 76:123-130. [PMID: 29742803 DOI: 10.1002/cm.21450] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Revised: 05/03/2018] [Accepted: 05/05/2018] [Indexed: 12/11/2022]
Abstract
We have shown previously that septin 9 isoform 1 (SEPT9_i1) protein associates with hypoxia-inducible factor (HIF)-1α to augment HIF-1 transcriptional activity by driving its importin-α-mediated nuclear translocation. Using in vitro and in vivo binding assays we identified that HIF-1α interacts with importin-α5 and importin-α7 in prostate cancer cells but only importin-α7 interacts with SEPT9_i1. The interaction with importin-α7 was dependent on the first 25 amino acids of SEPT9_i1 that are unique compared to other members of the mammalian septin family. Depletion of endogenous importin-α7 reduced HIF-1α levels in the nucleus. Our results provide evidence that there are importin-α specificities in the cytosolic/nuclear translocation process of HIF-1α protein, which may act differently under certain pathophysiological circumstances where SEPT9_i1 is overexpressed.
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Affiliation(s)
- Keren Tazat
- Prostate Cancer Research Laboratory, Department of Urology, Tel Aviv Sourasky Medical Center, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Susanne Schindler
- Institute of Physiology, Center for Structural and Cell Biology in Medicine, University of Lübeck, Ratzeburger Allee 160, 23562 Lübeck, Germany
| | - Reinhard Depping
- Institute of Physiology, Center for Structural and Cell Biology in Medicine, University of Lübeck, Ratzeburger Allee 160, 23562 Lübeck, Germany
| | - Nicola J Mabjeesh
- Prostate Cancer Research Laboratory, Department of Urology, Tel Aviv Sourasky Medical Center, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
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Roles of the CSE1L-mediated nuclear import pathway in epigenetic silencing. Proc Natl Acad Sci U S A 2018; 115:E4013-E4022. [PMID: 29636421 DOI: 10.1073/pnas.1800505115] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Epigenetic silencing can be mediated by various mechanisms, and many regulators remain to be identified. Here, we report a genome-wide siRNA screening to identify regulators essential for maintaining gene repression of a CMV promoter silenced by DNA methylation. We identified CSE1L (chromosome segregation 1 like) as an essential factor for the silencing of the reporter gene and many endogenous methylated genes. CSE1L depletion did not cause DNA demethylation. On the other hand, the methylated genes derepressed by CSE1L depletion largely overlapped with methylated genes that were also reactivated by treatment with histone deacetylase inhibitors (HDACi). Gene silencing defects observed upon CSE1L depletion were linked to its nuclear import function for certain protein cargos because depletion of other factors involved in the same nuclear import pathway, including KPNAs and KPNB1 proteins, displayed similar derepression profiles at the genome-wide level. Therefore, CSE1L appears to be critical for the nuclear import of certain key repressive proteins. Indeed, NOVA1, HDAC1, HDAC2, and HDAC8, genes known as silencing factors, became delocalized into cytosol upon CSE1L depletion. This study suggests that the cargo specificity of the protein nuclear import system may impact the selectivity of gene silencing.
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Döhner K, Ramos-Nascimento A, Bialy D, Anderson F, Hickford-Martinez A, Rother F, Koithan T, Rudolph K, Buch A, Prank U, Binz A, Hügel S, Lebbink RJ, Hoeben RC, Hartmann E, Bader M, Bauerfeind R, Sodeik B. Importin α1 is required for nuclear import of herpes simplex virus proteins and capsid assembly in fibroblasts and neurons. PLoS Pathog 2018; 14:e1006823. [PMID: 29304174 PMCID: PMC5773220 DOI: 10.1371/journal.ppat.1006823] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Revised: 01/18/2018] [Accepted: 12/16/2017] [Indexed: 01/28/2023] Open
Abstract
Herpesviruses are large DNA viruses which depend on many nuclear functions, and therefore on host transport factors to ensure specific nuclear import of viral and host components. While some import cargoes bind directly to certain transport factors, most recruit importin β1 via importin α. We identified importin α1 in a small targeted siRNA screen to be important for herpes simplex virus (HSV-1) gene expression. Production of infectious virions was delayed in the absence of importin α1, but not in cells lacking importin α3 or importin α4. While nuclear targeting of the incoming capsids, of the HSV-1 transcription activator VP16, and of the viral genomes were not affected, the nuclear import of the HSV-1 proteins ICP4 and ICP0, required for efficient viral transcription, and of ICP8 and pUL42, necessary for DNA replication, were reduced. Furthermore, quantitative electron microscopy showed that fibroblasts lacking importin α1 contained overall fewer nuclear capsids, but an increased proportion of mature nuclear capsids indicating that capsid formation and capsid egress into the cytoplasm were impaired. In neurons, importin α1 was also not required for nuclear targeting of incoming capsids, but for nuclear import of ICP4 and for the formation of nuclear capsid assembly compartments. Our data suggest that importin α1 is specifically required for the nuclear localization of several important HSV1 proteins, capsid assembly, and capsid egress into the cytoplasm, and may become rate limiting in situ upon infection at low multiplicity or in terminally differentiated cells such as neurons. Nuclear pore complexes are highly selective gateways that penetrate the nuclear envelope for bidirectional trafficking between the cytoplasm and the nucleoplasm. Viral and host cargoes have to engage specific transport factors to achieve active nuclear import and export. Like many human and animal DNA viruses, herpesviruses are critically dependent on many functions of the host cell nucleus. Alphaherpesviruses such as herpes simplex virus (HSV) cause many diseases upon productive infection in epithelial cells, fibroblasts and neurons. Here, we asked which nuclear transport factors of the host cells help HSV-1 to translocate viral components into the nucleus for viral gene expression, nuclear capsid assembly, capsid egress into the cytoplasm, and production of infectious virions. Our data show that HSV-1 requires the nuclear import factor importin α1 for efficient replication and virus assembly in fibroblasts and in mature neurons. To our knowledge this is the first time that a specific importin α isoform is shown to be required for herpesvirus infection. Our study fosters our understanding on how the different but highly homologous importin α isoforms could fulfill specific functions in vivo which are only understood for a very limited number of host and viral cargos.
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Affiliation(s)
- Katinka Döhner
- Institute of Virology, Hannover Medical School, Hannover, Germany
| | | | - Dagmara Bialy
- Institute of Virology, Hannover Medical School, Hannover, Germany
| | - Fenja Anderson
- Institute of Virology, Hannover Medical School, Hannover, Germany
| | | | - Franziska Rother
- Max-Delbrück Center for Molecular Medicine, Berlin-Buch, Germany
- Institute for Biology, University of Lübeck, Lübeck, Germany
| | - Thalea Koithan
- Institute of Virology, Hannover Medical School, Hannover, Germany
| | - Kathrin Rudolph
- Institute of Virology, Hannover Medical School, Hannover, Germany
| | - Anna Buch
- Institute of Virology, Hannover Medical School, Hannover, Germany
| | - Ute Prank
- Institute of Virology, Hannover Medical School, Hannover, Germany
| | - Anne Binz
- Institute of Virology, Hannover Medical School, Hannover, Germany
| | - Stefanie Hügel
- Max-Delbrück Center for Molecular Medicine, Berlin-Buch, Germany
- Institute for Biology, University of Lübeck, Lübeck, Germany
| | - Robert Jan Lebbink
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Rob C. Hoeben
- Department of Molecular Cell Biology, Leiden University Medical Center, Leiden, The Netherlands
| | - Enno Hartmann
- Institute for Biology, University of Lübeck, Lübeck, Germany
| | - Michael Bader
- Max-Delbrück Center for Molecular Medicine, Berlin-Buch, Germany
- Institute for Biology, University of Lübeck, Lübeck, Germany
| | - Rudolf Bauerfeind
- Research Core Unit Laser Microscopy, Hannover Medical School, Hannover, Germany
| | - Beate Sodeik
- Institute of Virology, Hannover Medical School, Hannover, Germany
- * E-mail:
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Sankhala RS, Lokareddy RK, Begum S, Pumroy RA, Gillilan RE, Cingolani G. Three-dimensional context rather than NLS amino acid sequence determines importin α subtype specificity for RCC1. Nat Commun 2017; 8:979. [PMID: 29042532 PMCID: PMC5645467 DOI: 10.1038/s41467-017-01057-7] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Accepted: 08/15/2017] [Indexed: 12/27/2022] Open
Abstract
Active nuclear import of Ran exchange factor RCC1 is mediated by importin α3. This pathway is essential to generate a gradient of RanGTP on chromatin that directs nucleocytoplasmic transport, mitotic spindle assembly and nuclear envelope formation. Here we identify the mechanisms of importin α3 selectivity for RCC1. We find this isoform binds RCC1 with one order of magnitude higher affinity than the generic importin α1, although the two isoforms share an identical NLS-binding groove. Importin α3 uses its greater conformational flexibility to wedge the RCC1 β-propeller flanking the NLS against its lateral surface, preventing steric clashes with its Armadillo-core. Removing the β-propeller, or inserting a linker between NLS and β-propeller, disrupts specificity for importin α3, demonstrating the structural context rather than NLS sequence determines selectivity for isoform 3. We propose importin α3 evolved to recognize topologically complex NLSs that lie next to bulky domains or are masked by quaternary structures.Importin α3 facilitates the nuclear transport of the Ran guanine nucleotide exchange factor RCC1. Here the authors reveal the molecular basis for the selectivity of RCC1 for importin α3 vs the generic importin α1 and discuss the evolution of importin α isoforms.
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Affiliation(s)
- Rajeshwer S Sankhala
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, 233 South 10th Street, Philadelphia, PA, 19107, USA
| | - Ravi K Lokareddy
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, 233 South 10th Street, Philadelphia, PA, 19107, USA
| | - Salma Begum
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, 233 South 10th Street, Philadelphia, PA, 19107, USA
| | - Ruth A Pumroy
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, 233 South 10th Street, Philadelphia, PA, 19107, USA.,Department of Biochemistry, University of Utah, 15N Medical Drive East, Salt Lake City, UT, 84112-5650, USA
| | - Richard E Gillilan
- Macromolecular Diffraction Facility, Cornell High Energy Synchrotron Source (MacCHESS), Cornell University, 161 Synchrotron Drive, Ithaca, NY, 14853, USA
| | - Gino Cingolani
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, 233 South 10th Street, Philadelphia, PA, 19107, USA. .,Institute of Biomembranes and Bioenergetics, National Research Council, Via Amendola 165/A, Bari, 70126, Italy.
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25
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Reprint of: Importins in the maintenance and lineage commitment of ES cells. Neurochem Int 2017; 106:14-23. [PMID: 28550879 DOI: 10.1016/j.neuint.2017.01.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 01/25/2017] [Accepted: 01/30/2017] [Indexed: 11/23/2022]
Abstract
The nucleus of a eukaryotic cell is separated from the cytoplasm by a nuclear envelope, and nuclear pores within the envelope facilitate nucleocytoplasmic transport and the exchange of information. Gene regulation is a key component of biological activity regulation in the cell. Transcription factors control the expression levels of various genes that are necessary for the maintenance or conversion of cellular states during animal development. Because transcription factor activities determine the extent of transcription of target genes, the number of active transcription factors must be tightly regulated. In this regard, the nuclear translocation of a transcription factor is an important determinant of its activity. Therefore, it is becoming clear that the nucleocytoplasmic transport machinery is involved in cell differentiation and organism development. This review examines the regulation of transcription factors by the nucleocytoplasmic transport machinery in ES cells.
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26
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Importins in the maintenance and lineage commitment of ES cells. Neurochem Int 2017; 105:32-41. [PMID: 28163061 DOI: 10.1016/j.neuint.2017.01.020] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 01/25/2017] [Accepted: 01/30/2017] [Indexed: 11/23/2022]
Abstract
The nucleus of a eukaryotic cell is separated from the cytoplasm by a nuclear envelope, and nuclear pores within the envelope facilitate nucleocytoplasmic transport and the exchange of information. Gene regulation is a key component of biological activity regulation in the cell. Transcription factors control the expression levels of various genes that are necessary for the maintenance or conversion of cellular states during animal development. Because transcription factor activities determine the extent of transcription of target genes, the number of active transcription factors must be tightly regulated. In this regard, the nuclear translocation of a transcription factor is an important determinant of its activity. Therefore, it is becoming clear that the nucleocytoplasmic transport machinery is involved in cell differentiation and organism development. This review examines the regulation of transcription factors by the nucleocytoplasmic transport machinery in ES cells.
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27
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Vuorinen EM, Rajala NK, Rauhala HE, Nurminen AT, Hytönen VP, Kallioniemi A. Search for KPNA7 cargo proteins in human cells reveals MVP and ZNF414 as novel regulators of cancer cell growth. Biochim Biophys Acta Mol Basis Dis 2016; 1863:211-219. [PMID: 27664836 DOI: 10.1016/j.bbadis.2016.09.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Revised: 08/26/2016] [Accepted: 09/20/2016] [Indexed: 12/20/2022]
Abstract
Karyopherin alpha 7 (KPNA7) belongs to a family of nuclear import proteins that recognize and bind nuclear localization signals (NLSs) in proteins to be transported to the nucleus. Previously we found that KPNA7 is overexpressed in a subset of pancreatic cancer cell lines and acts as a critical regulator of growth in these cells. This characteristic of KPNA7 is likely to be mediated by its cargo proteins that are still mainly unknown. Here, we used protein affinity chromatography in Hs700T and MIA PaCa-2 pancreatic cancer cell lines and identified 377 putative KPNA7 cargo proteins, most of which were known or predicted to localize to the nucleus. The interaction was confirmed for two of the candidates, MVP and ZNF414, using co-immunoprecipitation, and their transport to the nucleus was hindered by siRNA based KPNA7 silencing. Most importantly, silencing of MVP and ZNF414 resulted in marked reduction in Hs700T cell growth. In conclusion, these data uncover two previously unknown human KPNA7 cargo proteins with distinct roles as novel regulators of pancreatic cancer cell growth, thus deepening our understanding on the contribution of nuclear transport in cancer pathogenesis.
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Affiliation(s)
- Elisa M Vuorinen
- University of Tampere, BioMediTech, PL 100, 33014 TAMPEREEN YLIOPISTO, Tampere, Finland; Fimlab laboratories, Biokatu 4, 33520 Tampere, Finland.
| | - Nina K Rajala
- University of Tampere, BioMediTech, PL 100, 33014 TAMPEREEN YLIOPISTO, Tampere, Finland; Fimlab laboratories, Biokatu 4, 33520 Tampere, Finland.
| | - Hanna E Rauhala
- University of Tampere, BioMediTech, PL 100, 33014 TAMPEREEN YLIOPISTO, Tampere, Finland.
| | - Anssi T Nurminen
- University of Tampere, BioMediTech, PL 100, 33014 TAMPEREEN YLIOPISTO, Tampere, Finland; Fimlab laboratories, Biokatu 4, 33520 Tampere, Finland.
| | - Vesa P Hytönen
- University of Tampere, BioMediTech, PL 100, 33014 TAMPEREEN YLIOPISTO, Tampere, Finland; Fimlab laboratories, Biokatu 4, 33520 Tampere, Finland.
| | - Anne Kallioniemi
- University of Tampere, BioMediTech, PL 100, 33014 TAMPEREEN YLIOPISTO, Tampere, Finland; Fimlab laboratories, Biokatu 4, 33520 Tampere, Finland.
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28
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Loveland KL, Major AT, Butler R, Young JC, Jans DA, Miyamoto Y. Putting things in place for fertilization: discovering roles for importin proteins in cell fate and spermatogenesis. Asian J Androl 2016; 17:537-44. [PMID: 25994647 PMCID: PMC4492042 DOI: 10.4103/1008-682x.154310] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Importin proteins were originally characterized for their central role in protein transport through the nuclear pores, the only intracellular entry to the nucleus. This vital function must be tightly regulated to control access by transcription factors and other nuclear proteins to genomic DNA, to achieve appropriate modulation of cellular behaviors affecting cell fate. Importin-mediated nucleocytoplasmic transport relies on their specific recognition of cargoes, with each importin binding to distinct and overlapping protein subsets. Knowledge of importin function has expanded substantially in regard to three key developmental systems: embryonic stem cells, muscle cells and the germ line. In the decade since the potential for regulated nucleocytoplasmic transport to contribute to spermatogenesis was proposed, we and others have shown that the importins that ferry transcription factors into the nucleus perform additional roles, which control cell fate. This review presents key findings from studies of mammalian spermatogenesis that reveal potential new pathways by which male fertility and infertility arise. These studies of germline genesis illuminate new ways in which importin proteins govern cellular differentiation, including via directing proteins to distinct intracellular compartments and by determining cellular stress responses.
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Affiliation(s)
- Kate L Loveland
- Department of Biochemistry and Molecular Biology;Department of Anatomy and Developmental Biology, Monash University; Hudson Institute of Medical Research, Monash Medical Centre; School of Clinical Sciences, Monash University, Clayton, VIC, Australia,
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29
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Xu Y, Li L, Li J, Liu Q. Structural and biological function of NYD-SP15 as a new member of cytidine deaminases. Gene 2016; 583:36-47. [PMID: 26945630 DOI: 10.1016/j.gene.2016.02.048] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Revised: 02/16/2016] [Accepted: 02/21/2016] [Indexed: 11/26/2022]
Abstract
Recent studies were mainly focus on the cytidine deaminase family genes, which contained a lot of members that varied on the function of catalytic deamination in RNA or DNA and were involved in the process of growth maintenance, host immunity, retroviral infection, tumorigenesis, and drug resistance with a feature of C-U deamination. In this study, we identified a new member of cytidine deaminase family, NYD-SP15. Previous work showed that the deduced structure of the protein contained two dCMP_cyt_deam domains, which were involved in zinc ion binding. NYD-SP15 was expressed variably in a wide range of tissues, indicating its worthy biological function and creative significances. Sequence analysis, RT-PCR, western blot, flow cytometry, direct-site mutation and GST pull-down assay were performed to analyze the construction and function of NYD-SP15. The results in our studies showed that NYD-SP15 was closely related to deoxycytidylate deaminase and cytidine deaminase, with authentic cytidine deaminase activity in vivo and vitro as well as homo dimerization effects. NYD-SP15 contained nuclear localization sequence (NLS) and nuclear export-signal (NES) and could dynamically shuttle between the nucleus and cytoplasm. Furthermore, NYD-SP15 gene over-expression reduced the cells growth and blocked G1 to S phase, which implied a potential inhibition effect on cell growth.
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Affiliation(s)
- Yidan Xu
- Department of Ophthalmology, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China
| | - Lei Li
- Department of Pharmacology, Basic Medical Sciences of Nanjing Medical University, Nanjing, Jiangsu 210029, China
| | - Jianmin Li
- Department of Ophthalmology, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China.
| | - Qinghuai Liu
- Department of Ophthalmology, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China
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Roggero VR, Zhang J, Parente LE, Doshi Y, Dziedzic RC, McGregor EL, Varjabedian AD, Schad SE, Bondzi C, Allison LA. Nuclear import of the thyroid hormone receptor α1 is mediated by importin 7, importin β1, and adaptor importin α1. Mol Cell Endocrinol 2016; 419:185-97. [PMID: 26525414 PMCID: PMC4684427 DOI: 10.1016/j.mce.2015.10.016] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Revised: 10/20/2015] [Accepted: 10/20/2015] [Indexed: 01/27/2023]
Abstract
The thyroid hormone receptor α1 (TRα1) is a nuclear receptor for thyroid hormone that shuttles rapidly between the nucleus and cytoplasm. Our prior studies showed that nuclear import of TRα1 is directed by two nuclear localization signals, one in the N-terminal A/B domain and the other in the hinge domain. Here, we showed using in vitro nuclear import assays that TRα1 nuclear localization is temperature and energy-dependent and can be reconstituted by the addition of cytosol. In HeLa cells expressing green fluorescent protein (GFP)-tagged TRα1, knockdown of importin 7, importin β1 and importin α1 by RNA interference, or treatment with an importin β1-specific inhibitor, significantly reduced nuclear localization of TRα1, while knockdown of other importins had no effect. Coimmunoprecipitation assays confirmed that TRα1 interacts with importin 7, as well as importin β1 and the adapter importin α1, suggesting that TRα1 trafficking into the nucleus is mediated by two distinct pathways.
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Affiliation(s)
- Vincent R Roggero
- Department of Biology, College of William and Mary, Williamsburg, VA, 23185, USA
| | - Jibo Zhang
- Department of Biology, College of William and Mary, Williamsburg, VA, 23185, USA
| | - Laura E Parente
- Department of Biology, College of William and Mary, Williamsburg, VA, 23185, USA
| | - Yazdi Doshi
- Department of Biology, College of William and Mary, Williamsburg, VA, 23185, USA
| | - Rose C Dziedzic
- Department of Biology, College of William and Mary, Williamsburg, VA, 23185, USA
| | - Emma L McGregor
- Department of Biology, College of William and Mary, Williamsburg, VA, 23185, USA
| | - Arev D Varjabedian
- Department of Biology, College of William and Mary, Williamsburg, VA, 23185, USA
| | - Sara E Schad
- Department of Biology, College of William and Mary, Williamsburg, VA, 23185, USA
| | - Cornelius Bondzi
- Department of Biological Sciences, Hampton University, Hampton, VA, 23668, USA
| | - Lizabeth A Allison
- Department of Biology, College of William and Mary, Williamsburg, VA, 23185, USA.
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31
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Abstract
In this issue of Structure, Pumroy and colleagues have solved the crystal structure of the influenza virus polymerase PB2 C-terminal domain complexed with different Importin αs. Combining molecular dynamics with structural and biochemical data, the so-far elusive basis for selectivity of binding to distinct different importin αs is beginning to become accessible.
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Affiliation(s)
- Gualtiero Alvisi
- Department of Molecular Medicine, University of Padua, 35121 Padua, Italy
| | - David A Jans
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC 3800, Australia.
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32
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Abstract
The human genome encodes seven isoforms of importin α which are grouped into three subfamilies known as α1, α2 and α3. All isoforms share a fundamentally conserved architecture that consists of an N-terminal, autoinhibitory, importin-β-binding (IBB) domain and a C-terminal Arm (Armadillo)-core that associates with nuclear localization signal (NLS) cargoes. Despite striking similarity in amino acid sequence and 3D structure, importin-α isoforms display remarkable substrate specificity in vivo. In the present review, we look at key differences among importin-α isoforms and provide a comprehensive inventory of known viral and cellular cargoes that have been shown to associate preferentially with specific isoforms. We illustrate how the diversification of the adaptor importin α into seven isoforms expands the dynamic range and regulatory control of nucleocytoplasmic transport, offering unexpected opportunities for pharmacological intervention. The emerging view of importin α is that of a key signalling molecule, with isoforms that confer preferential nuclear entry and spatiotemporal specificity on viral and cellular cargoes directly linked to human diseases.
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33
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Depping R, Jelkmann W, Kosyna FK. Nuclear-cytoplasmatic shuttling of proteins in control of cellular oxygen sensing. J Mol Med (Berl) 2015; 93:599-608. [PMID: 25809665 DOI: 10.1007/s00109-015-1276-0] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Revised: 03/04/2015] [Accepted: 03/11/2015] [Indexed: 12/11/2022]
Abstract
In order to pass through the nuclear pore complex, proteins larger than ∼40 kDa require specific nuclear transport receptors. Defects in nuclear-cytoplasmatic transport affect fundamental processes such as development, inflammation and oxygen sensing. The transcriptional response to O2 deficiency is controlled by hypoxia-inducible factors (HIFs). These are heterodimeric transcription factors of each ∼100-120 kDa proteins, consisting of one out of three different O2-labile α subunits (primarily HIF-1α) and a more constitutive 1β subunit. In the presence of O2, the α subunits are hydroxylated by specific prolyl-4-hydroxylase domain proteins (PHD1, PHD2, and PHD3) and an asparaginyl hydroxylase (factor inhibiting HIF-1, FIH-1). The prolyl hydroxylation causes recognition by von Hippel-Lindau tumor suppressor protein (pVHL), ubiquitination, and proteasomal degradation. The activity of the oxygen sensing machinery depends on dynamic intracellular trafficking. Nuclear import of HIF-1α and HIF-1β is mainly mediated by importins α and β (α/β). HIF-1α can shuttle between nucleus and cytoplasm, while HIF-1β is permanently inside the nucleus. pVHL is localized to both compartments. Nuclear import of PHD1 relies on a nuclear localization signal (NLS) and uses the classical import pathway involving importin α/β receptors. PHD2 shows an atypical NLS, and its nuclear import does not occur via the classical pathway. PHD2-mediated hydroxylation of HIF-1α occurs predominantly in the cell nucleus. Nuclear export of PHD2 involves a nuclear export signal (NES) in the N-terminus and depends on the export receptor chromosome region maintenance 1 (CRM1). Nuclear import of PHD3 is mediated by importin α/β receptors and depends on a non-classical NLS. Specific modification of the nuclear translocation of the three PHD isoforms could provide a promising strategy for the development of new therapeutic substances to tackle major diseases.
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Affiliation(s)
- Reinhard Depping
- Institute of Physiology, Centre for Structural and Cell Biology in Medicine, University of Lübeck, Lübeck, Germany,
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34
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Di Girolamo M. Regulation of nucleocytoplasmic transport by ADP-ribosylation: the emerging role of karyopherin-β1 mono-ADP-ribosylation by ARTD15. Curr Top Microbiol Immunol 2015; 384:189-209. [PMID: 25037261 DOI: 10.1007/82_2014_421] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Post-translational modifications of a cellular protein by mono- and poly-ADP-ribosylation involve the cleavage of NAD (+) , with the release of its nicotinamide moiety. This is accompanied by the transfer of a single (mono-) or several (poly-) ADP-ribose molecules from NAD (+) to a specific amino-acid residue of the protein. Recent reports have shed new light on the correlation between NAD (+) -dependent ADP-ribosylation reactions and the endoplasmic reticulum, in addition to the well-documented roles of these reactions in the nucleus and mitochondria. We have demonstrated that ARTD15/PARP16 is a novel mono-ADP-ribosyltransferase with a new intracellular location, as it is associated with the endoplasmic reticulum. The endoplasmic reticulum, which is a membranous network of interconnected tubules and cisternae, is responsible for specialised cellular functions, including protein folding and protein transport. Maintenance of specialised cellular functions requires the correct flow of information between separate organelles that is made possible through the nucleocytoplasmic trafficking of proteins. ARTD15 appears to have a role in nucleocytoplasmic shuttling, through karyopherin-β1 mono-ADP-ribosylation. This is in line with the emerging role of ADP-ribosylation in the regulation of intracellular trafficking of cellular proteins. Indeed, other, ADP-ribosyltransferases like ARTD1/PARP1, have been reported to regulate nucleocytoplasmic trafficking of crucial proteins, including p53 and NF-κB, and as a consequence, to modulate the subcellular localisation of these proteins under both physiological and pathological conditions.
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Affiliation(s)
- Maria Di Girolamo
- G-Protein-Mediated Signalling Laboratory, Fondazione Mario Negri Sud, Via Nazionale 8/A, 66030, S. Maria Imbaro (CH), Italy,
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Molecular determinants for nuclear import of influenza A PB2 by importin α isoforms 3 and 7. Structure 2015; 23:374-84. [PMID: 25599645 DOI: 10.1016/j.str.2014.11.015] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Revised: 11/14/2014] [Accepted: 11/18/2014] [Indexed: 11/23/2022]
Abstract
Influenza A virus polymerase subunit PB2 is a major virulence determinant implicated in pathogenicity and host adaptation. During cross-species virus transfer from avian to mammalian cells, PB2 switches specificity from importin α3 to α7. This specificity is not recapitulated in vitro, where PB2 binds all importin α isoforms with comparably high affinity. In this study, we investigated the structure, conformational dynamics, and autoinhibition of importin α isoforms 1, 3, and 7 in complex with PB2. Our data suggest that association of PB2 with α3 and α7 is favored by reduced autoinhibition of these isoforms and by the unique structure of the nuclear localization signal (NLS) domain of PB2. We propose that by recruiting importin α3 or α7 in the absence of importin β, PB2 reduces the complexity of adaptor-mediated import to a pseudo-bimolecular reaction, thereby acquiring a kinetic advantage over classical NLS cargos, which form an import complex only when importin α and β are simultaneously available.
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Kulshreshtha V, Ayalew LE, Islam A, Tikoo SK. Conserved arginines of bovine adenovirus-3 33K protein are important for transportin-3 mediated transport and virus replication. PLoS One 2014; 9:e101216. [PMID: 25019945 PMCID: PMC4096500 DOI: 10.1371/journal.pone.0101216] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2014] [Accepted: 06/04/2014] [Indexed: 01/14/2023] Open
Abstract
The L6 region of bovine adenovirus (BAdV)-3 encodes a spliced protein designated 33K. The 33K specific sera detected five major proteins and three minor proteins in transfected or virus infected cells, which could arise by internal initiation of translation and alternative splicing. The 33K protein is predominantly localized to the nucleus of BAdV-3 infected cells. The 33K nuclear transport utilizes both classical importin-α/-β and importin-β dependent nuclear import pathways and preferentially binds to importin-α5 and transportin-3 receptors, respectively. Analysis of mutant 33K proteins demonstrated that amino acids 201–240 of the conserved C-terminus of 33K containing RS repeat are required for nuclear localization and, binding to both importin-α5 and transportin-3 receptors. Interestingly, the arginine residues of conserved RS repeat are required for binding to transportin-3 receptor but not to importin-α5 receptor. Moreover, mutation of arginines residues of RS repeat proved lethal for production of progeny virus. Our results suggest that arginines of RS repeat are required for efficient nuclear transport of 33K mediated by transportin-3, which appears to be essential for replication and production of infectious virion.
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Affiliation(s)
- Vikas Kulshreshtha
- VIDO-InterVac, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
- Veterinary Microbiology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Lisanework E. Ayalew
- VIDO-InterVac, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
- Veterinary Microbiology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Azharul Islam
- VIDO-InterVac, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Suresh K. Tikoo
- VIDO-InterVac, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
- Veterinary Microbiology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
- Vaccinology & Immunotherapeutics Program, School of Public Health, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
- * E-mail:
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Hügel S, Depping R, Dittmar G, Rother F, Cabot R, Sury MD, Hartmann E, Bader M. Identification of importin α 7 specific transport cargoes using a proteomic screening approach. Mol Cell Proteomics 2014; 13:1286-98. [PMID: 24623588 DOI: 10.1074/mcp.m112.026856] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The importin α:β complex is responsible for the nuclear import of proteins bearing classical nuclear localization signals. In mammals, several importin α subtypes are known to exist that are suggested to have individual functions. Importin α 7 was shown to play a crucial role in early embryonic development in mice. Embryos from importin α 7-depleted females stop at the two-cell stage and show disturbed zygotic genome activation. As there is evidence that individual importin α subtypes possess cargo specificities, we hypothesized that importin α 7 binds a unique set of intracellular proteins. With the use of a collection of in vitro and in vivo binding assays, importin α 7 interaction partners were identified that differed from proteins found to bind to importin α 2 and 3. One of the proteins preferentially binding importin α 7 was the maternal effect protein Brg1. However, Brg1 was localized in oocyte nuclei in importin α 7-deficient embryos, albeit in reduced amounts, suggesting additional modes of nuclear translocation of this factor. An additional SILAC-based screening approach identified Ash2l, Chd3, Mcm3, and Smarcc1, whose nuclear import seems to be disturbed in importin α 7-deficient fibroblasts.
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Affiliation(s)
- Stefanie Hügel
- Max Delbrück Center of Molecular Medicine, 13125 Berlin, Germany
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Zienkiewicz J, Armitage A, Hawiger J. Targeting nuclear import shuttles, importins/karyopherins alpha by a peptide mimicking the NFκB1/p50 nuclear localization sequence. J Am Heart Assoc 2013; 2:e000386. [PMID: 24042087 PMCID: PMC3835248 DOI: 10.1161/jaha.113.000386] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background We recently reported that a bifunctional nuclear transport modifier (NTM), cSN50.1 peptide, reduced atherosclerosis, plasma cholesterol, triglycerides, and glucose along with liver fat and inflammatory markers, in a murine model of familial hypercholesterolemia. We determined that cSN50.1 improved lipid homeostasis by modulating nuclear transport of sterol regulatory element‐binding proteins through interaction with importin β. Previous studies established that cSN50.1 and related NTMs also modulate nuclear transport of proinflammatory transcription factors mediated by binding of their nuclear localization sequences (NLSs) to importins/karyopherins α. However, selectivity and specificity of NTMs for importins/karyopherins α were undetermined. Methods and Results We analyzed interaction of the NTM hydrophilic module, N50 peptide, derived from the NLS of NFκB1/p50, with endogenous human importins/karyopherins α to determine the mechanism of NTM modulation of importin α‐mediated nuclear transport. We show that N50 peptide forms stable complexes with multiple importins/karyopherins α. However, only interaction with importin α5 (Imp α5) displayed specific, high‐affinity binding. The 2:1 stoichiometry of the N50‐Imp α5 interaction (KD1=73 nmol/L, KD2=140 nmol/L) indicated occupancy of both major and minor NLS binding pockets. Utilizing in silico 3‐dimensional (3‐D) docking models and comparative structural analysis, we identified a structural component of the Imp α5 major NLS binding pocket that may stabilize N50 binding. Imp α5 also displayed rapid stimulus‐induced turnover, which could influence its availability for nuclear transport during the inflammatory response. Conclusions These results provide direct evidence that N50 peptide selectively targets Imp α5, encouraging further refinement of NLS‐derived peptides as new tools to modulate inflammatory disorders.
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Affiliation(s)
- Jozef Zienkiewicz
- Division of Allergy, Pulmonary and Critical Care Medicine, Department of Medicine, Vanderbilt University School of Medicine, Nashville, 37232, TN
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Kimura M, Okumura N, Kose S, Takao T, Imamoto N. Identification of cargo proteins specific for importin-β with importin-α applying a stable isotope labeling by amino acids in cell culture (SILAC)-based in vitro transport system. J Biol Chem 2013; 288:24540-9. [PMID: 23846694 DOI: 10.1074/jbc.m113.489286] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The human importin (Imp)-β family consists of 21 nucleocytoplasmic transport carrier proteins, which transport thousands of proteins (cargoes) across the nuclear envelope through nuclear pores in specific directions. To understand the nucleocytoplasmic transport in a physiological context, the specificity of cargoes for their cognate carriers should be determined; however, only a limited number of nuclear proteins have been linked to specific carriers. To address this biological question, we recently developed a novel method to identify carrier-specific cargoes. This method includes the following three steps: (i) the cells are labeled by stable isotope labeling by amino acids in cell culture (SILAC); (ii) the labeled cells are permeabilized, and proteins in the unlabeled cell extracts are transported into the nuclei of the permeabilized cells by a particular carrier; and (iii) the proteins in the nuclei are quantitatively identified by LC-MS/MS. The effectiveness of this method was demonstrated by the identification of transportin (Trn)-specific cargoes. Here, we applied this method to identify cargo proteins specific for Imp-β, which is a predominant carrier that exclusively utilizes Imp-α as an adapter for cargo binding. We identified candidate cargoes, which included previously reported and potentially novel Imp-β cargoes. In in vitro binding assays, most of the candidate cargoes bound to Imp-β in one of three binding modes: directly, via Imp-α, or via other cargoes. Thus, our method is effective for identifying a variety of Imp-β cargoes. The identified Imp-β and Trn cargoes were compared, ensuring the carrier specificity of the method and illustrating the complexity of these transport pathways.
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Affiliation(s)
- Makoto Kimura
- Cellular Dynamics Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
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Hannemann H, Sung PY, Chiu HC, Yousuf A, Bird J, Lim SP, Davidson AD. Serotype-specific differences in dengue virus non-structural protein 5 nuclear localization. J Biol Chem 2013; 288:22621-35. [PMID: 23770669 DOI: 10.1074/jbc.m113.481382] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The four serotypes of dengue virus (DENV-1 to -4) cause the most important arthropod-borne viral disease of humans. DENV non-structural protein 5 (NS5) contains enzymatic activities required for capping and replication of the viral RNA genome that occurs in the host cytoplasm. However, previous studies have shown that DENV-2 NS5 accumulates in the nucleus during infection. In this study, we examined the nuclear localization of NS5 for all four DENV serotypes. We demonstrate for the first time that there are serotypic differences in NS5 nuclear localization. Whereas the DENV-2 and -3 proteins accumulate in the nucleus, DENV-1 and -4 NS5 are predominantly if not exclusively localized to the cytoplasm. Comparative studies on the DENV-2 and -4 NS5 proteins revealed that the difference in DENV-4 NS5 nuclear localization was not due to rapid nuclear export but rather the lack of a functional nuclear localization sequence. Interaction studies using DENV-2 and -4 NS5 and human importin-α isoforms failed to identify an interaction that supported the differential nuclear localization of NS5. siRNA knockdown of the human importin-α isoform KPNA2, corresponding to the murine importin-α isoform previously shown to bind to DENV-2 NS5, did not substantially affect DENV-2 NS5 nuclear localization, whereas knockdown of importin-β did. The serotypic differences in NS5 nuclear localization did not correlate with differences in IL-8 gene expression. The results show that NS5 nuclear localization is not strictly required for virus replication but is more likely to have an auxiliary function in the life cycle of specific DENV serotypes.
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Affiliation(s)
- Holger Hannemann
- School of Cellular and Molecular Medicine, Faculty of Medical and Veterinary Sciences, University of Bristol, University Walk, Bristol BS8 1TD, United Kingdom
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Peptide inhibitor of NF-κB translocation ameliorates experimental atherosclerosis. THE AMERICAN JOURNAL OF PATHOLOGY 2013; 182:1910-21. [PMID: 23597852 DOI: 10.1016/j.ajpath.2013.01.022] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2012] [Revised: 12/17/2012] [Accepted: 01/10/2013] [Indexed: 11/22/2022]
Abstract
Atherosclerosis is a chronic inflammatory disease of the arterial wall. NF-κB is a major regulator of inflammation that controls the expression of many genes involved in atherogenesis. Activated NF-κB was detected in human atherosclerotic plaques, and modulation of NF-κB inflammatory activity limits disease progression in mice. Herein, we investigate the anti-inflammatory and atheroprotective effects of a cell-permeable peptide containing the NF-κB nuclear localization sequence (NLS). In vascular smooth muscle cells and macrophages, NLS peptide specifically blocked the importin α-mediated nuclear import of NF-κB and prevented lipopolysaccharide-induced pro-inflammatory gene expression, cell migration, and oxidative stress. In experimental atherosclerosis (apolipoprotein E-knockout mice fed a high-fat diet), i.p., 0.13 μmol/day NLS peptide administration for 5 weeks attenuated NF-κB activation in atherosclerotic plaques. NLS peptide significantly inhibited lesion development at both early (age 10 weeks) and advanced (age 28 weeks) stages of atherosclerosis in mice, without affecting serum lipid levels. Plaques from NLS-treated mice contained fewer macrophages of pro-inflammatory M1 subtype than those from respective untreated controls. By contrast, the relative smooth muscle cell and collagen content was increased, indicating a more stable plaque phenotype. NLS peptide also attenuated pro-inflammatory gene expression and oxidative stress in aortic lesions. Our study demonstrates that targeting NF-κB nuclear translocation hampers inflammation and atherosclerosis development and identifies cell-permeable NLS peptide as a potential anti-atherosclerotic agent.
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RNAi phenotypes are influenced by the genetic background of the injected strain. BMC Genomics 2013; 14:5. [PMID: 23324472 PMCID: PMC3574008 DOI: 10.1186/1471-2164-14-5] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2012] [Accepted: 12/19/2012] [Indexed: 12/22/2022] Open
Abstract
Background RNA interference (RNAi) is a powerful tool to study gene function in organisms that are not amenable to classical forward genetics. Hence, together with the ease of comprehensively identifying genes by new generation sequencing, RNAi is expanding the scope of animal species and questions that can be addressed in terms of gene function. In the case of genetic mutants, the genetic background of the strains used is known to influence the phenotype while this has not been described for RNAi experiments. Results Here we show in the red flour beetle Tribolium castaneum that RNAi against Tc-importin α1 leads to different phenotypes depending on the injected strain. We rule out off target effects and show that sequence divergence does not account for this difference. By quantitatively comparing phenotypes elicited by RNAi knockdown of four different genes we show that there is no general difference in RNAi sensitivity between these strains. Finally, we show that in case of Tc-importin α1 the difference depends on the maternal genotype. Conclusions These results show that in RNAi experiments strain specific differences have to be considered and that a proper documentation of the injected strain is required. This is especially important for the increasing number of emerging model organisms that are being functionally investigated using RNAi. In addition, our work shows that RNAi is suitable to systematically identify the differences in the gene regulatory networks present in populations of the same species, which will allow novel insights into the evolution of animal diversity.
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Resa-Infante P, Gabriel G. The nuclear import machinery is a determinant of influenza virus host adaptation. Bioessays 2012; 35:23-7. [DOI: 10.1002/bies.201200138] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Al Abdallah Q, Choe SI, Campoli P, Baptista S, Gravelat FN, Lee MJ, Sheppard DC. A conserved C-terminal domain of the Aspergillus fumigatus developmental regulator MedA is required for nuclear localization, adhesion and virulence. PLoS One 2012. [PMID: 23185496 PMCID: PMC3503810 DOI: 10.1371/journal.pone.0049959] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
MedA is a developmental regulator that is conserved in the genome of most filamentous fungi. In the pathogenic fungus Aspergillus fumigatus MedA regulates conidiogenesis, adherence to host cells, and pathogenicity. The mechanism by which MedA governs these phenotypes remains unknown. Although the nuclear import of MedA orthologues has been reported in other fungi, no nuclear localization signal, DNA-binding domain or other conserved motifs have been identified within MedA. In this work, we performed a deletion analysis of MedA and identified a novel domain within the C-terminal region of the protein, designated MedA346–557, that is necessary and sufficient for nuclear localization of MedA. We further demonstrate that MedA nuclear localization is required for the function of MedA. Surprisingly, expression of the minimal nuclear localization fragment MedA346–557 alone was sufficient to restore conidogenesis, biofilm formation and virulence to the medA mutant strain. Collectively these results suggest that MedA functions in the regulation of transcription, and that the MedA346–557 domain is both necessary and sufficient to mediate MedA function.
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Affiliation(s)
- Qusai Al Abdallah
- Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada
| | - Se-In Choe
- Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada
| | - Paolo Campoli
- Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada
| | - Stefanie Baptista
- Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada
| | - Fabrice N. Gravelat
- Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada
| | - Mark J. Lee
- Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada
| | - Donald C. Sheppard
- Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada
- Department of Medicine, McGill University, Montreal, Quebec, Canada
- * E-mail:
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Functional eukaryotic nuclear localization signals are widespread in terminal proteins of bacteriophages. Proc Natl Acad Sci U S A 2012; 109:18482-7. [PMID: 23091024 DOI: 10.1073/pnas.1216635109] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
A number of prokaryotic proteins have been shown to contain nuclear localization signals (NLSs), although its biological role remains sometimes unclear. Terminal proteins (TPs) of bacteriophages prime DNA replication and become covalently linked to the genome ends. We predicted NLSs within the TPs of bacteriophages from diverse families and hosts and, indeed, the TPs of Φ29, Nf, PRD1, Bam35, and Cp-1, out of seven TPs tested, were found to localize to the nucleus when expressed in mammalian cells. Detailed analysis of Φ29 TP led us to identify a bona fide NLS within residues 1-37. Importantly, gene delivery into the eukaryotic nucleus is enhanced by the presence of Φ29 TP attached to the 5' DNA ends. These findings show a common feature of TPs from diverse bacteriophages targeting the eukaryotic nucleus and suggest a possible common function by facilitating the horizontal transfer of genes between prokaryotes and eukaryotes.
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Paterson CP, Ayalew LE, Tikoo SK. Mapping of nuclear import signal and importin α3 binding regions of 52K protein of bovine adenovirus-3. Virology 2012; 432:63-72. [PMID: 22739443 DOI: 10.1016/j.virol.2012.05.021] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2012] [Revised: 04/24/2012] [Accepted: 05/24/2012] [Indexed: 11/19/2022]
Abstract
The L1 region of bovine adenovirus (BAdV)-3 encodes a non-structural protein designated 52K. Anti-52K serum detected a protein of 40kDa, which localized to the nucleus but not to the nucleolus in BAdV-3-infected or transfected cells. Analysis of mutant 52K proteins suggested that three basic residues ((105)RKR(107)) of the identified domain (amino acids (102)GMPRKRVLT(110)) are essential for nuclear localization of 52K. The nuclear import of a GST-52K fusion protein utilizes the classical importin α/β-dependent nuclear transport pathway. The 52K protein is preferentially bound to the cellular nuclear import receptor importin α3. Although deletion of amino acid 102-110 is sufficient to abrogate the nuclear localization of 52K, amino acid 90-133 are required for interaction with importin-α3 and localizing a cytoplasmic protein to the nucleus. These results suggest that 52K contains a bipartite NLS, which preferentially utilize an importin α3 nuclear import receptor-mediated pathway to transport 52K to the nucleus.
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Affiliation(s)
- Carolyn P Paterson
- Vaccine & Infectious Disease Organization-International Vaccine Center, University of Saskatchewan, Saskatoon, SK S7N 5E3 Canada
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Belacortu Y, Weiss R, Kadener S, Paricio N. Transcriptional activity and nuclear localization of Cabut, the Drosophila ortholog of vertebrate TGF-β-inducible early-response gene (TIEG) proteins. PLoS One 2012; 7:e32004. [PMID: 22359651 PMCID: PMC3281117 DOI: 10.1371/journal.pone.0032004] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2011] [Accepted: 01/17/2012] [Indexed: 01/26/2023] Open
Abstract
Background Cabut (Cbt) is a C2H2-class zinc finger transcription factor involved in embryonic dorsal closure, epithelial regeneration and other developmental processes in Drosophila melanogaster. Cbt orthologs have been identified in other Drosophila species and insects as well as in vertebrates. Indeed, Cbt is the Drosophila ortholog of the group of vertebrate proteins encoded by the TGF-ß-inducible early-response genes (TIEGs), which belong to Sp1-like/Krüppel-like family of transcription factors. Several functional domains involved in transcriptional control and subcellular localization have been identified in the vertebrate TIEGs. However, little is known of whether these domains and functions are also conserved in the Cbt protein. Methodology/Principal Findings To determine the transcriptional regulatory activity of the Drosophila Cbt protein, we performed Gal4-based luciferase assays in S2 cells and showed that Cbt is a transcriptional repressor and able to regulate its own expression. Truncated forms of Cbt were then generated to identify its functional domains. This analysis revealed a sequence similar to the mSin3A-interacting repressor domain found in vertebrate TIEGs, although located in a different part of the Cbt protein. Using β-Galactosidase and eGFP fusion proteins, we also showed that Cbt contains the bipartite nuclear localization signal (NLS) previously identified in TIEG proteins, although it is non-functional in insect cells. Instead, a monopartite NLS, located at the amino terminus of the protein and conserved across insects, is functional in Drosophila S2 and Spodoptera exigua Sec301 cells. Last but not least, genetic interaction and immunohistochemical assays suggested that Cbt nuclear import is mediated by Importin-α2. Conclusions/Significance Our results constitute the first characterization of the molecular mechanisms of Cbt-mediated transcriptional control as well as of Cbt nuclear import, and demonstrate the existence of similarities and differences in both aspects of Cbt function between the insect and the vertebrate TIEG proteins.
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Affiliation(s)
- Yaiza Belacortu
- Departamento de Genética, Facultad CC Biológicas, Universidad de Valencia, Burjasot, Spain
| | - Ron Weiss
- Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, Hebrew University of Jerusalem, Edmond J. Safra Campus, Givat-Ram, Jerusalem, Israel
| | - Sebastian Kadener
- Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, Hebrew University of Jerusalem, Edmond J. Safra Campus, Givat-Ram, Jerusalem, Israel
| | - Nuria Paricio
- Departamento de Genética, Facultad CC Biológicas, Universidad de Valencia, Burjasot, Spain
- * E-mail:
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Human-like PB2 627K influenza virus polymerase activity is regulated by importin-α1 and -α7. PLoS Pathog 2012; 8:e1002488. [PMID: 22275867 PMCID: PMC3262014 DOI: 10.1371/journal.ppat.1002488] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2011] [Accepted: 12/02/2011] [Indexed: 11/19/2022] Open
Abstract
Influenza A viruses may cross species barriers and transmit to humans with the potential to cause pandemics. Interplay of human- (PB2 627K) and avian-like (PB2 627E) influenza polymerase complexes with unknown host factors have been postulated to play a key role in interspecies transmission. Here, we have identified human importin-α isoforms (α1 and α7) as positive regulators of human- but not avian-like polymerase activity. Human-like polymerase activity correlated with efficient recruitment of α1 and α7 to viral ribonucleoprotein complexes (vRNPs) without affecting subcellular localization. We also observed that human-like influenza virus growth was impaired in α1 and α7 downregulated human lung cells. Mice lacking α7 were less susceptible to human- but not avian-like influenza virus infection. Thus, α1 and α7 are positive regulators of human-like polymerase activity and pathogenicity beyond their role in nuclear transport. Adaptive mutations in the polymerase complex, such as PB2 E627K and PB2 D701N play a crucial role in influenza virus interspecies transmission. We have shown earlier that PB2 D701N promotes nuclear entry of PB2 by enhanced importin-α binding in mammalian cells (Gabriel et al., PLoS Pathogens 2008; Gabriel et al., Nat. Commun. 2011). In this study, we show that the adaptive mutation PB2 E627K involves an interaction with importin-α by a novel mechanism that does not mediate nuclear transport of viral factors. We found that human importin-α1 and -α7 are required for efficient human- (PB2 627K) but not avian-like (PB2 627E) polymerase activity. Further, human-like polymerase activity correlated with enhanced importin-α1 and -α7 binding to viral ribonucleoprotein complexes (vRNP). Mice lacking importin-α7 were less susceptible to human-like but not avian-like influenza virus infection. Our findings strongly suggest that importin-α isoforms possess functions beyond their primary role in nuclear transport facilitating PB2 E627K mediated host adaptation and pathogenicity.
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Tuteja R, Mehta J. A genomic glance at the components of the mRNA export machinery in Plasmodium falciparum. Commun Integr Biol 2011; 3:318-26. [PMID: 20798816 DOI: 10.4161/cib.3.4.11886] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2010] [Accepted: 03/24/2010] [Indexed: 01/29/2023] Open
Abstract
Nuclear export of mRNAs is one of the steps critically important for gene expression and different steps of mRNA processing are linked to the export of the mRNA out of the nucleus. This coupling probably provides a quality control mechanism as well as a higher efficiency for the synthesis of mRNAs. The mRNA is synthesized in the nucleus and then exported to the cytoplasm through the nuclear pore complexes (NPCs), which are embedded in the nuclear envelope. The Mex67-Mtr2 complex in yeast and its counterpart Tap-p15 in higher eukaryotes function as an mRNA exporter through the NPC. Some of the DEAD box proteins such as UAP56 and Dbp5 have been implicated in mRNA export also. In this report using the bioinformatics approach we have analyzed the components of the mRNA export machinery in Plasmodium falciparum and also highlighted the salient features of some of the components. Further detailed studies on various components of nuclear mRNA export in Plasmodium falciparum will be essential to understand this important pathway.
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Affiliation(s)
- Renu Tuteja
- Malaria Group; International Centre for Genetic Engineering and Biotechnology; Aruna Asaf Ali Marg, New Delhi India
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Holt JE, Ly-Huynh JD, Efthymiadis A, Hime GR, Loveland KL, Jans DA. Regulation of Nuclear Import During Differentiation; The IMP alpha Gene Family and Spermatogenesis. Curr Genomics 2011; 8:323-34. [PMID: 19384428 PMCID: PMC2652405 DOI: 10.2174/138920207782446151] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2007] [Revised: 06/09/2007] [Accepted: 06/10/2007] [Indexed: 11/30/2022] Open
Abstract
Access to nuclear genes in eukaryotes is provided by members of the importin (IMP) superfamily of proteins, which are of α- or β-types, the best understood nuclear import pathway being mediated by a heterodimer of an IMP α and IMP β1. IMP α recognises specific targeting signals on cargo proteins, while IMP β1 mediates passage into, and release within, the nucleus by interacting with other components of the transport machinery, including the monomeric guanine nucleotide binding protein Ran. In this manner, hundreds of different proteins can be targeted specifically into the nucleus in a tightly regulated fashion. The IMP α gene family has expanded during evolution, with only a single IMP α (Srp1p) gene in budding yeast, and three (IMP α1, 2/pendulin and 3) and five (IMP α1, -2, -3, -4 and -6) IMP α genes in Drosophila melanogaster and mouse respectively, which fall into three phylogenetically distinct groups. The fact that IMP α3 and IMP α2 are only present in metazoans implies that they emerged during the evolution of multicellular animals to perform specialised roles in particular cells and tissues. This review describes what is known of the IMP α gene family in mouse and in D. melanogaster, including a comparitive examination of their mRNA expression profiles in a highly differentiated tissue, the testis. The clear implication of their highly regulated synthesis during the course of spermatogenesis is that the different IMP αs have distinct expression patterns during cellular differentiation, implying tissue/cell type-specific roles.
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Affiliation(s)
- J E Holt
- Monash University, Department of Biochemistry and Molecular Biology, Nuclear Signalling Laboratory, Clayton, Australia
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