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Kubitscheck U, Siebrasse JP. Pre-ribosomal particles from nucleoli to cytoplasm. Nucleus 2024; 15:2373052. [PMID: 38940456 PMCID: PMC11216097 DOI: 10.1080/19491034.2024.2373052] [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: 04/02/2024] [Accepted: 06/21/2024] [Indexed: 06/29/2024] Open
Abstract
The analysis of nucleocytoplasmic transport of proteins and messenger RNA has been the focus of advanced microscopic approaches. Recently, it has been possible to identify and visualize individual pre-ribosomal particles on their way through the nuclear pore complex using both electron and light microscopy. In this review, we focused on the transport of pre-ribosomal particles in the nucleus on their way to and through the pores.
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Affiliation(s)
- Ulrich Kubitscheck
- Clausius Institute of Physical and Theoretical Chemistry, University of Bonn, Bonn, Germany
| | - Jan Peter Siebrasse
- Clausius Institute of Physical and Theoretical Chemistry, University of Bonn, Bonn, Germany
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2
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Ngo LH, Bert AG, Dredge BK, Williams T, Murphy V, Li W, Hamilton WB, Carey KT, Toubia J, Pillman KA, Liu D, Desogus J, Chao JA, Deans AJ, Goodall GJ, Wickramasinghe VO. Nuclear export of circular RNA. Nature 2024; 627:212-220. [PMID: 38355801 DOI: 10.1038/s41586-024-07060-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Accepted: 01/12/2024] [Indexed: 02/16/2024]
Abstract
Circular RNAs (circRNAs), which are increasingly being implicated in a variety of functions in normal and cancerous cells1-5, are formed by back-splicing of precursor mRNAs in the nucleus6-10. circRNAs are predominantly localized in the cytoplasm, indicating that they must be exported from the nucleus. Here we identify a pathway that is specific for the nuclear export of circular RNA. This pathway requires Ran-GTP, exportin-2 and IGF2BP1. Enhancing the nuclear Ran-GTP gradient by depletion or chemical inhibition of the major protein exporter CRM1 selectively increases the nuclear export of circRNAs, while reducing the nuclear Ran-GTP gradient selectively blocks circRNA export. Depletion or knockout of exportin-2 specifically inhibits nuclear export of circRNA. Analysis of nuclear circRNA-binding proteins reveals that interaction between IGF2BP1 and circRNA is enhanced by Ran-GTP. The formation of circRNA export complexes in the nucleus is promoted by Ran-GTP through its interactions with exportin-2, circRNA and IGF2BP1. Our findings demonstrate that adaptors such as IGF2BP1 that bind directly to circular RNAs recruit Ran-GTP and exportin-2 to export circRNAs in a mechanism that is analogous to protein export, rather than mRNA export.
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Affiliation(s)
- Linh H Ngo
- RNA Biology and Cancer Laboratory, Peter MacCallum Cancer Centre and Sir Peter MacCallum Department of Oncology, University of Melbourne, Melbourne, Victoria, Australia
| | - Andrew G Bert
- Centre for Cancer Biology, University of South Australia and SA Pathology, Adelaide, South Australia, Australia
| | - B Kate Dredge
- Centre for Cancer Biology, University of South Australia and SA Pathology, Adelaide, South Australia, Australia
- Adelaide Centre for Epigenetics, School of Biomedicine, Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, South Australia, Australia
- South Australian immunoGENomics Cancer Institute (SAiGENCI), Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, South Australia, Australia
| | - Tobias Williams
- RNA Biology and Cancer Laboratory, Peter MacCallum Cancer Centre and Sir Peter MacCallum Department of Oncology, University of Melbourne, Melbourne, Victoria, Australia
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Vincent Murphy
- Genome Stability Unit, St Vincent's Institute of Medical Research, Fitzroy, Victoria, Australia
| | - Wanqiu Li
- RNA Biology and Cancer Laboratory, Peter MacCallum Cancer Centre and Sir Peter MacCallum Department of Oncology, University of Melbourne, Melbourne, Victoria, Australia
- Department of Pharmacology, Joint Laboratory of Guangdong-Hong Kong Universities for Vascular Homeostasis and Diseases, School of Medicine and Institute for Biological Electron Microscopy, Southern University of Science and Technology, Shenzhen, China
| | - William B Hamilton
- RNA Biology and Cancer Laboratory, Peter MacCallum Cancer Centre and Sir Peter MacCallum Department of Oncology, University of Melbourne, Melbourne, Victoria, Australia
| | - Kirstyn T Carey
- RNA Biology and Cancer Laboratory, Peter MacCallum Cancer Centre and Sir Peter MacCallum Department of Oncology, University of Melbourne, Melbourne, Victoria, Australia
| | - John Toubia
- Centre for Cancer Biology, University of South Australia and SA Pathology, Adelaide, South Australia, Australia
| | - Katherine A Pillman
- Centre for Cancer Biology, University of South Australia and SA Pathology, Adelaide, South Australia, Australia
- Department of Molecular and Biomedical Science, University of Adelaide, Adelaide, South Australia, Australia
| | - Dawei Liu
- Centre for Cancer Biology, University of South Australia and SA Pathology, Adelaide, South Australia, Australia
| | - Jessica Desogus
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Jeffrey A Chao
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Andrew J Deans
- Genome Stability Unit, St Vincent's Institute of Medical Research, Fitzroy, Victoria, Australia
| | - Gregory J Goodall
- Centre for Cancer Biology, University of South Australia and SA Pathology, Adelaide, South Australia, Australia.
- Department of Molecular and Biomedical Science, University of Adelaide, Adelaide, South Australia, Australia.
- Department of Medicine, University of Adelaide, Adelaide, South Australia, Australia.
| | - Vihandha O Wickramasinghe
- RNA Biology and Cancer Laboratory, Peter MacCallum Cancer Centre and Sir Peter MacCallum Department of Oncology, University of Melbourne, Melbourne, Victoria, Australia.
- Department of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Victoria, Australia.
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3
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Kodiha M, Azad N, Chu S, Crampton N, Stochaj U. Oxidative stress and signaling through EGFR and PKA pathways converge on the nuclear transport factor RanBP1. Eur J Cell Biol 2024; 103:151376. [PMID: 38011756 DOI: 10.1016/j.ejcb.2023.151376] [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: 09/30/2023] [Revised: 11/01/2023] [Accepted: 11/17/2023] [Indexed: 11/29/2023] Open
Abstract
Nuclear protein trafficking requires the soluble transport factor RanBP1. The subcellular distribution of RanBP1 is dynamic, as the protein shuttles between the nucleus and cytoplasm. To date, the signaling pathways regulating RanBP1 subcellular localization are poorly understood. During interphase, RanBP1 resides mostly in the cytoplasm. We show here that oxidative stress concentrates RanBP1 in the nucleus, and our study defines the underlying mechanisms. Specifically, RanBP1's cysteine residues are not essential for its oxidant-induced relocation. Furthermore, our pharmacological approaches uncover that signaling mediated by epidermal growth factor receptor (EGFR) and protein kinase A (PKA) control RanBP1 localization during stress. In particular, pharmacological inhibitors of EGFR or PKA diminish the oxidant-dependent relocation of RanBP1. Mutant analysis identified serine 60 and tyrosine 103 as regulators of RanBP1 nuclear accumulation during oxidant exposure. Taken together, our results define RanBP1 as a target of oxidative stress and a downstream effector of EGFR and PKA signaling routes. This positions RanBP1 at the intersection of important cellular signaling circuits.
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Affiliation(s)
- Mohamed Kodiha
- Department of Physiology McGill University, Montreal H3G 1Y6, Canada
| | - Nabila Azad
- Department of Physiology McGill University, Montreal H3G 1Y6, Canada
| | - Siwei Chu
- Department of Physiology McGill University, Montreal H3G 1Y6, Canada
| | - Noah Crampton
- Department of Physiology McGill University, Montreal H3G 1Y6, Canada
| | - Ursula Stochaj
- Department of Physiology McGill University, Montreal H3G 1Y6, Canada.
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4
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Kapinos LE, Kalita J, Kassianidou E, Rencurel C, Lim RYH. Mechanism of exportin retention in the cell nucleus. J Cell Biol 2024; 223:e202306094. [PMID: 38241019 PMCID: PMC10798875 DOI: 10.1083/jcb.202306094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 11/06/2023] [Accepted: 12/07/2023] [Indexed: 01/22/2024] Open
Abstract
Exportin receptors are concentrated in the nucleus to transport essential cargoes out of it. A mislocalization of exportins to the cytoplasm is linked to disease. Hence, it is important to understand how their containment within the nucleus is regulated. Here, we have studied the nuclear efflux of exportin2 (cellular apoptosis susceptibility protein or CAS) that delivers karyopherinα (Kapα or importinα), the cargo adaptor for karyopherinβ1 (Kapβ1 or importinβ1), to the cytoplasm in a Ran guanosine triphosphate (RanGTP)-mediated manner. We show that the N-terminus of CAS attenuates the interaction of RanGTPase activating protein 1 (RanGAP1) with RanGTP to slow GTP hydrolysis, which suppresses CAS nuclear exit at nuclear pore complexes (NPCs). Strikingly, a single phosphomimetic mutation (T18D) at the CAS N-terminus is sufficient to abolish its nuclear retention and coincides with metastatic cellular behavior. Furthermore, downregulating Kapβ1 disrupts CAS nuclear retention, which highlights the balance between their respective functions that is essential for maintaining the Kapα transport cycle. Therefore, NPCs play a functional role in selectively partitioning exportins in the cell nucleus.
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Affiliation(s)
- Larisa E. Kapinos
- Biozentrum and the Swiss Nanoscience Institute, University of Basel Switzerland, Basel, Switzerland
| | - Joanna Kalita
- Biozentrum and the Swiss Nanoscience Institute, University of Basel Switzerland, Basel, Switzerland
| | - Elena Kassianidou
- Biozentrum and the Swiss Nanoscience Institute, University of Basel Switzerland, Basel, Switzerland
| | - Chantal Rencurel
- Biozentrum and the Swiss Nanoscience Institute, University of Basel Switzerland, Basel, Switzerland
| | - Roderick Y. H. Lim
- Biozentrum and the Swiss Nanoscience Institute, University of Basel Switzerland, Basel, Switzerland
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5
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Baum B, Spang A. On the origin of the nucleus: a hypothesis. Microbiol Mol Biol Rev 2023; 87:e0018621. [PMID: 38018971 PMCID: PMC10732040 DOI: 10.1128/mmbr.00186-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2023] Open
Abstract
SUMMARYIn this hypothesis article, we explore the origin of the eukaryotic nucleus. In doing so, we first look afresh at the nature of this defining feature of the eukaryotic cell and its core functions-emphasizing the utility of seeing the eukaryotic nucleoplasm and cytoplasm as distinct regions of a common compartment. We then discuss recent progress in understanding the evolution of the eukaryotic cell from archaeal and bacterial ancestors, focusing on phylogenetic and experimental data which have revealed that many eukaryotic machines with nuclear activities have archaeal counterparts. In addition, we review the literature describing the cell biology of representatives of the TACK and Asgardarchaeaota - the closest known living archaeal relatives of eukaryotes. Finally, bringing these strands together, we propose a model for the archaeal origin of the nucleus that explains much of the current data, including predictions that can be used to put the model to the test.
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Affiliation(s)
- Buzz Baum
- MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Cambridge, United Kingdom
| | - Anja Spang
- Department of Marine Microbiology and Biogeochemistry, NIOZ, Royal Netherlands Institute for Sea Research, Den Burg, the Netherlands
- Department of Evolutionary & Population Biology, Institute for Biodiversity and Ecosystem Dynamics (IBED), University of Amsterdam, Amsterdam, the Netherlands
- Department of Marine Microbiology and Biogeochemistry, NIOZ, Royal Netherlands Institute for Sea Research, Den Burg, the Netherlands
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Yang Y, Guo L, Chen L, Gong B, Jia D, Sun Q. Nuclear transport proteins: structure, function, and disease relevance. Signal Transduct Target Ther 2023; 8:425. [PMID: 37945593 PMCID: PMC10636164 DOI: 10.1038/s41392-023-01649-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2023] [Revised: 09/13/2023] [Accepted: 09/14/2023] [Indexed: 11/12/2023] Open
Abstract
Proper subcellular localization is crucial for the functioning of biomacromolecules, including proteins and RNAs. Nuclear transport is a fundamental cellular process that regulates the localization of many macromolecules within the nuclear or cytoplasmic compartments. In humans, approximately 60 proteins are involved in nuclear transport, including nucleoporins that form membrane-embedded nuclear pore complexes, karyopherins that transport cargoes through these complexes, and Ran system proteins that ensure directed and rapid transport. Many of these nuclear transport proteins play additional and essential roles in mitosis, biomolecular condensation, and gene transcription. Dysregulation of nuclear transport is linked to major human diseases such as cancer, neurodegenerative diseases, and viral infections. Selinexor (KPT-330), an inhibitor targeting the nuclear export factor XPO1 (also known as CRM1), was approved in 2019 to treat two types of blood cancers, and dozens of clinical trials of are ongoing. This review summarizes approximately three decades of research data in this field but focuses on the structure and function of individual nuclear transport proteins from recent studies, providing a cutting-edge and holistic view on the role of nuclear transport proteins in health and disease. In-depth knowledge of this rapidly evolving field has the potential to bring new insights into fundamental biology, pathogenic mechanisms, and therapeutic approaches.
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Affiliation(s)
- Yang Yang
- Department of Pulmonary and Critical Care Medicine, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Lu Guo
- Department of Pulmonary and Critical Care Medicine, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Lin Chen
- Department of Pulmonary and Critical Care Medicine, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Bo Gong
- The Key Laboratory for Human Disease Gene Study of Sichuan Province and Department of Laboratory Medicine, Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, China
- Research Unit for Blindness Prevention of Chinese Academy of Medical Sciences (2019RU026), Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, Chengdu, China
| | - Da Jia
- Key Laboratory of Birth Defects and Related Diseases of Women and Children, Department of Pediatrics, West China Second University Hospital, State Key Laboratory of Biotherapy, Sichuan University, Chengdu, China.
| | - Qingxiang Sun
- Department of Pulmonary and Critical Care Medicine, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China.
- Department of Pathology, State Key Laboratory of Biotherapy and Cancer Centre, West China Hospital, Sichuan University, and Collaborative Innovation Centre of Biotherapy, Chengdu, China.
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7
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Mghezzi-Habellah M, Prochasson L, Jalinot P, Mocquet V. Viral Subversion of the Chromosome Region Maintenance 1 Export Pathway and Its Consequences for the Cell Host. Viruses 2023; 15:2218. [PMID: 38005895 PMCID: PMC10674744 DOI: 10.3390/v15112218] [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: 09/18/2023] [Revised: 10/28/2023] [Accepted: 11/01/2023] [Indexed: 11/26/2023] Open
Abstract
In eukaryotic cells, the spatial distribution between cytoplasm and nucleus is essential for cell homeostasis. This dynamic distribution is selectively regulated by the nuclear pore complex (NPC), which allows the passive or energy-dependent transport of proteins between these two compartments. Viruses possess many strategies to hijack nucleocytoplasmic shuttling for the benefit of their viral replication. Here, we review how viruses interfere with the karyopherin CRM1 that controls the nuclear export of protein cargoes. We analyze the fact that the viral hijacking of CRM1 provokes are-localization of numerous cellular factors in a suitable place for specific steps of viral replication. While CRM1 emerges as a critical partner for viruses, it also takes part in antiviral and inflammatory response regulation. This review also addresses how CRM1 hijacking affects it and the benefits of CRM1 inhibitors as antiviral treatments.
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Affiliation(s)
| | | | | | - Vincent Mocquet
- Laboratoire de Biologie et Modélisation de la Cellule, Ecole Normale Supérieure-Lyon, Université Claude Bernard Lyon, U1293, UMR5239, 69364 Lyon, France; (M.M.-H.); (L.P.); (P.J.)
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8
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Liao CC, Wang YS, Pi WC, Wang CH, Wu YM, Chen WY, Hsia KC. Structural convergence endows nuclear transport receptor Kap114p with a transcriptional repressor function toward TATA-binding protein. Nat Commun 2023; 14:5518. [PMID: 37684250 PMCID: PMC10491584 DOI: 10.1038/s41467-023-41206-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Accepted: 08/24/2023] [Indexed: 09/10/2023] Open
Abstract
The transcription factor TATA-box binding protein (TBP) modulates gene expression in nuclei. This process requires the involvement of nuclear transport receptors, collectively termed karyopherin-β (Kap-β) in yeast, and various regulatory factors. In previous studies we showed that Kap114p, a Kap-β that mediates nuclear import of yeast TBP (yTBP), modulates yTBP-dependent transcription. However, how Kap114p associates with yTBP to exert its multifaceted functions has remained elusive. Here, we employ single-particle cryo-electron microscopy to determine the structure of Kap114p in complex with the core domain of yTBP (yTBPC). Remarkably, Kap114p wraps around the yTBPC N-terminal lobe, revealing a structure resembling transcriptional regulators in complex with TBP, suggesting convergent evolution of the two protein groups for a common function. We further demonstrate that Kap114p sequesters yTBP away from promoters, preventing a collapse of yTBP dynamics required for yeast responses to environmental stress. Hence, we demonstrate that nuclear transport receptors represent critical elements of the transcriptional regulatory network.
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Affiliation(s)
- Chung-Chi Liao
- Molecular and Cell Biology, Taiwan International Graduate Program, Academia Sinica and National Defense Medical Center, Taipei, 11490, Taiwan
- Institute of Molecular Biology, Academia Sinica, Taipei, 11529, Taiwan
| | - Yi-Sen Wang
- Institute of Molecular Biology, Academia Sinica, Taipei, 11529, Taiwan
| | - Wen-Chieh Pi
- Institute of Biochemistry and Molecular Biology, College of Life Sciences, National Yang Ming Chiao Tung University, Taipei, 11221, Taiwan
| | - Chun-Hsiung Wang
- Institute of Biological Chemistry, Academia Sinica, Taipei, 11529, Taiwan
| | - Yi-Min Wu
- Institute of Biological Chemistry, Academia Sinica, Taipei, 11529, Taiwan
| | - Wei-Yi Chen
- Institute of Biochemistry and Molecular Biology, College of Life Sciences, National Yang Ming Chiao Tung University, Taipei, 11221, Taiwan.
- Cancer and Immunology Research Center, National Yang Ming Chiao Tung University, Taipei, 11221, Taiwan.
| | - Kuo-Chiang Hsia
- Molecular and Cell Biology, Taiwan International Graduate Program, Academia Sinica and National Defense Medical Center, Taipei, 11490, Taiwan.
- Institute of Molecular Biology, Academia Sinica, Taipei, 11529, Taiwan.
- Institute of Biochemistry and Molecular Biology, College of Life Sciences, National Yang Ming Chiao Tung University, Taipei, 11221, Taiwan.
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Wang H, Teng X, Lin Y, Jiang C, Chen X, Zhang Y. Targeting XPO6 inhibits prostate cancer progression and enhances the suppressive efficacy of docetaxel. Discov Oncol 2023; 14:82. [PMID: 37243787 DOI: 10.1007/s12672-023-00700-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Accepted: 05/22/2023] [Indexed: 05/29/2023] Open
Abstract
BACKGROUND Although XPO6, one of the Exportin family members, functions in malignant progression of certain types of cancer, its role in prostate cancer (PCa) has not been elucidated. Herein, we investigated the oncogenic effect and clarified the downstream mechanism of XPO6 in PCa cells. METHODS We detected the expression level of XPO6 in PCa tissues by immunohistochemistry (IHC) and analyzed the correlation between clinicopathological characteristics and XPO6 level based on TCGA database. The effects of XPO6 in the proliferation and migration or resistance to docetaxel (DTX) in PCa cells were assessed using CCK8, colony formation, wound-healing and Transwell assays. Mice experiments were performed to investigate the role of XPO6 in tumor progression and DTX effect in vivo. Further, functional analysis of DEGs revealed the correlation of XPO6 with Hippo pathway and XPO6 could promote the expression and nuclear translocation of YAP1 protein. Furthermore, blocking Hippo pathway with YAP1 inhibitor leads to the loss of XPO6-mediated regulation of biological functions. RESULTS XPO6 was highly expressed and positively correlated with the clinicopathological characteristics of PCa. Functional experiments indicated that XPO6 could promote tumor development and DTX resistance in PCa. Mechanistically, we further confirmed that XPO6 could regulate Hippo pathway via mediating YAP1 protein expression and nuclear translocation thereby promoting PCa progression and chemotherapeutic resistance. CONCLUSION In conclusion, our research reveals that XPO6 potentially function as an oncogene and promotes DTX resistance of PCa, suggesting that XPO6 could be both a potential prognostic marker as well as a therapeutic target to effectively overcome DTX resistance.
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Affiliation(s)
- Huming Wang
- Department of Urology, The Second Affiliated Hospital of Anhui Medical University, No.678, Furong Road, Shushan District, Hefei, 230601, P.R. China
| | - Xiangyu Teng
- Department of Urology, The Second Affiliated Hospital of Anhui Medical University, No.678, Furong Road, Shushan District, Hefei, 230601, P.R. China
| | - Yuan Lin
- Department of Urology, The Second Affiliated Hospital of Anhui Medical University, No.678, Furong Road, Shushan District, Hefei, 230601, P.R. China
| | - Chao Jiang
- Department of Urology, The Second Affiliated Hospital of Anhui Medical University, No.678, Furong Road, Shushan District, Hefei, 230601, P.R. China
| | - Xin Chen
- Department of Urology, The Second Affiliated Hospital of Anhui Medical University, No.678, Furong Road, Shushan District, Hefei, 230601, P.R. China
| | - Ying Zhang
- Department of Urology, The Second Affiliated Hospital of Anhui Medical University, No.678, Furong Road, Shushan District, Hefei, 230601, P.R. China.
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10
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El-Tanani M, Nsairat H, Mishra V, Mishra Y, Aljabali AAA, Serrano-Aroca Á, Tambuwala MM. Ran GTPase and Its Importance in Cellular Signaling and Malignant Phenotype. Int J Mol Sci 2023; 24:ijms24043065. [PMID: 36834476 PMCID: PMC9968026 DOI: 10.3390/ijms24043065] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 01/10/2023] [Accepted: 01/11/2023] [Indexed: 02/08/2023] Open
Abstract
Ran is a member of the Ras superfamily of proteins, which primarily regulates nucleocytoplasmic trafficking and mediates mitosis by regulating spindle formation and nuclear envelope (NE) reassembly. Therefore, Ran is an integral cell fate determinant. It has been demonstrated that aberrant Ran expression in cancer is a result of upstream dysregulation of the expression of various factors, such as osteopontin (OPN), and aberrant activation of various signaling pathways, including the extracellular-regulated kinase/mitogen-activated protein kinase (ERK/MEK) and phosphatidylinositol 3-kinase/Protein kinase B (PI3K/Akt) pathways. In vitro, Ran overexpression has severe effects on the cell phenotype, altering proliferation, adhesion, colony density, and invasion. Therefore, Ran overexpression has been identified in numerous types of cancer and has been shown to correlate with tumor grade and the degree of metastasis present in various cancers. The increased malignancy and invasiveness have been attributed to multiple mechanisms. Increased dependence on Ran for spindle formation and mitosis is a consequence of the upregulation of these pathways and the ensuing overexpression of Ran, which increases cellular dependence on Ran for survival. This increases the sensitivity of cells to changes in Ran concentration, with ablation being associated with aneuploidy, cell cycle arrest, and ultimately, cell death. It has also been demonstrated that Ran dysregulation influences nucleocytoplasmic transport, leading to transcription factor misallocation. Consequently, patients with tumors that overexpress Ran have been shown to have a higher malignancy rate and a shorter survival time compared to their counterparts.
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Affiliation(s)
- Mohamed El-Tanani
- Pharmacological and Diagnostic Research Centre, Faculty of Pharmacy, Al-Ahliyya Amman University, Amman 19328, Jordan
- Correspondence:
| | - Hamdi Nsairat
- Pharmacological and Diagnostic Research Centre, Faculty of Pharmacy, Al-Ahliyya Amman University, Amman 19328, Jordan
| | - Vijay Mishra
- School of Pharmaceutical Sciences, Lovely Professional University, Phagwara 144411, India
| | - Yachana Mishra
- Department of Zoology, School of Bioengineering and Biosciences, Lovely Professional University, Phagwara 144411, India
| | - Alaa A. A. Aljabali
- Department of Pharmaceutics & Pharmaceutical Technology, Yarmouk University, Irbid 21163, Jordan
| | - Ángel Serrano-Aroca
- Biomaterials and Bioengineering Laboratory, Centro de Investigación Traslacional San Alberto Magno, Universidad Católica de Valencia San Vicente Mártir, c/Guillem de Castro 94, 46001 Valencia, Spain
| | - Murtaza M. Tambuwala
- Lincoln Medical School, University of Lincoln, Brayford Pool, Lincoln LN6 7TS, UK
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11
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Lista MJ, Ficarelli M, Wilson H, Kmiec D, Youle RL, Wanford J, Winstone H, Odendall C, Taylor IA, Neil SJD, Swanson CM. A Nuclear Export Signal in KHNYN Required for Its Antiviral Activity Evolved as ZAP Emerged in Tetrapods. J Virol 2023; 97:e0087222. [PMID: 36633408 PMCID: PMC9888277 DOI: 10.1128/jvi.00872-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Accepted: 12/20/2022] [Indexed: 01/13/2023] Open
Abstract
The zinc finger antiviral protein (ZAP) inhibits viral replication by directly binding CpG dinucleotides in cytoplasmic viral RNA to inhibit protein synthesis and target the RNA for degradation. ZAP evolved in tetrapods and there are clear orthologs in reptiles, birds, and mammals. When ZAP emerged, other proteins may have evolved to become cofactors for its antiviral activity. KHNYN is a putative endoribonuclease that is required for ZAP to restrict retroviruses. To determine its evolutionary path after ZAP emerged, we compared KHNYN orthologs in mammals and reptiles to those in fish, which do not encode ZAP. This identified residues in KHNYN that are highly conserved in species that encode ZAP, including several in the CUBAN domain. The CUBAN domain interacts with NEDD8 and Cullin-RING E3 ubiquitin ligases. Deletion of the CUBAN domain decreased KHNYN antiviral activity, increased protein expression and increased nuclear localization. However, mutation of residues required for the CUBAN domain-NEDD8 interaction increased KHNYN abundance but did not affect its antiviral activity or cytoplasmic localization, indicating that Cullin-mediated degradation may control its homeostasis and regulation of protein turnover is separable from its antiviral activity. By contrast, the C-terminal residues in the CUBAN domain form a CRM1-dependent nuclear export signal (NES) that is required for its antiviral activity. Deletion or mutation of the NES increased KHNYN nuclear localization and decreased its interaction with ZAP. The final 2 positions of this NES are not present in fish KHNYN orthologs and we hypothesize their evolution allowed KHNYN to act as a ZAP cofactor. IMPORTANCE The interferon system is part of the innate immune response that inhibits viruses and other pathogens. This system emerged approximately 500 million years ago in early vertebrates. Since then, some genes have evolved to become antiviral interferon-stimulated genes (ISGs) while others evolved so their encoded protein could interact with proteins encoded by ISGs and contribute to their activity. However, this remains poorly characterized. ZAP is an ISG that arose during tetrapod evolution and inhibits viral replication. Because KHNYN interacts with ZAP and is required for its antiviral activity against retroviruses, we conducted an evolutionary analysis to determine how specific amino acids in KHNYN evolved after ZAP emerged. This identified a nuclear export signal that evolved in tetrapods and is required for KHNYN to traffic in the cell and interact with ZAP. Overall, specific residues in KHNYN evolved to allow it to act as a cofactor for ZAP antiviral activity.
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Affiliation(s)
- Maria J. Lista
- King’s College London, Department of Infectious Diseases, London, United Kingdom
| | - Mattia Ficarelli
- King’s College London, Department of Infectious Diseases, London, United Kingdom
| | - Harry Wilson
- King’s College London, Department of Infectious Diseases, London, United Kingdom
| | - Dorota Kmiec
- King’s College London, Department of Infectious Diseases, London, United Kingdom
| | - Rebecca L. Youle
- King’s College London, Department of Infectious Diseases, London, United Kingdom
- The Francis Crick Institute, Macromolecular Structure Laboratory, London, United Kingdom
| | - Joseph Wanford
- King’s College London, Department of Infectious Diseases, London, United Kingdom
| | - Helena Winstone
- King’s College London, Department of Infectious Diseases, London, United Kingdom
| | - Charlotte Odendall
- King’s College London, Department of Infectious Diseases, London, United Kingdom
| | - Ian A. Taylor
- The Francis Crick Institute, Macromolecular Structure Laboratory, London, United Kingdom
| | - Stuart J. D. Neil
- King’s College London, Department of Infectious Diseases, London, United Kingdom
| | - Chad M. Swanson
- King’s College London, Department of Infectious Diseases, London, United Kingdom
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12
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Tingey M, Li Y, Yu W, Young A, Yang W. Spelling out the roles of individual nucleoporins in nuclear export of mRNA. Nucleus 2022; 13:170-193. [PMID: 35593254 PMCID: PMC9132428 DOI: 10.1080/19491034.2022.2076965] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 05/08/2022] [Accepted: 05/09/2022] [Indexed: 11/01/2022] Open
Abstract
The Nuclear Pore Complex (NPC) represents a critical passage through the nuclear envelope for nuclear import and export that impacts nearly every cellular process at some level. Recent technological advances in the form of Auxin Inducible Degron (AID) strategies and Single-Point Edge-Excitation sub-Diffraction (SPEED) microscopy have enabled us to provide new insight into the distinct functions and roles of nuclear basket nucleoporins (Nups) upon nuclear docking and export for mRNAs. In this paper, we provide a review of our recent findings as well as an assessment of new techniques, updated models, and future perspectives in the studies of mRNA's nuclear export.
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Affiliation(s)
- Mark Tingey
- Department of Biology, Temple University, Philadelphia, Pennsylvania, USA
| | - Yichen Li
- Department of Genetics, Yale School of Medicine, Yale University, New Haven, Connecticut, USA
| | - Wenlan Yu
- Department of Biology, Temple University, Philadelphia, Pennsylvania, USA
| | - Albert Young
- Department of Biology, Temple University, Philadelphia, Pennsylvania, USA
| | - Weidong Yang
- Department of Biology, Temple University, Philadelphia, Pennsylvania, USA
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13
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Hou T, Tian Y, Cao Z, Zhang J, Feng T, Tao W, Sun H, Wen H, Lu X, Zhu Q, Li M, Lu X, Liu B, Zhao Y, Yang Y, Zhu WG. Cytoplasmic SIRT6-mediated ACSL5 deacetylation impedes nonalcoholic fatty liver disease by facilitating hepatic fatty acid oxidation. Mol Cell 2022; 82:4099-4115.e9. [PMID: 36208627 DOI: 10.1016/j.molcel.2022.09.018] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Revised: 08/08/2022] [Accepted: 09/16/2022] [Indexed: 11/05/2022]
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14
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Jin G, Zhang Z, Wan J, Wu X, Liu X, Zhang W. G3BP2: Structure and Function. Pharmacol Res 2022; 186:106548. [DOI: 10.1016/j.phrs.2022.106548] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Revised: 10/20/2022] [Accepted: 11/02/2022] [Indexed: 11/06/2022]
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15
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Panagiotopoulos AA, Kalyvianaki K, Tsodoulou PK, Darivianaki MN, Dellis D, Notas G, Daskalakis V, Theodoropoulos PA, Panagiotidis CΑ, Castanas E, Kampa M. Recognition motifs for importin 4 [(L)PPRS(G/P)P] and importin 5 [KP(K/Y)LV] binding, identified by bio-informatic simulation and experimental in vitro validation. Comput Struct Biotechnol J 2022; 20:5952-5961. [PMID: 36382187 PMCID: PMC9646746 DOI: 10.1016/j.csbj.2022.10.015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Revised: 10/10/2022] [Accepted: 10/11/2022] [Indexed: 01/21/2023] Open
Abstract
Nuclear translocation of large proteins is mediated through karyopherins, carrier proteins recognizing specific motifs of cargo proteins, known as nuclear localization signals (NLS). However, only few NLS signals have been reported until now. In the present work, NLS signals for Importins 4 and 5 were identified through an unsupervised in silico approach, followed by experimental in vitro validation. The sequences LPPRS(G/P)P and KP(K/Y)LV were identified and are proposed as recognition motifs for Importins 4 and 5 binding, respectively. They are involved in the trafficking of important proteins into the nucleus. These sequences were validated in the breast cancer cell line T47D, which expresses both Importins 4 and 5. Elucidating the complex relationships of the nuclear transporters and their cargo proteins is very important in better understanding the mechanism of nuclear transport of proteins and laying the foundation for the development of novel therapeutics, targeting specific importins.
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Affiliation(s)
| | - Konstantina Kalyvianaki
- Laboratory of Experimental Endocrinology, School of Medicine, University of Crete, 71013, Greece
| | - Paraskevi K. Tsodoulou
- Laboratory of Pharmacology, School of Pharmacy, Aristotle University of Thessaloniki, Thessaloniki 54124, Greece
| | - Maria N. Darivianaki
- Laboratory of Pharmacology, School of Pharmacy, Aristotle University of Thessaloniki, Thessaloniki 54124, Greece
| | - Dimitris Dellis
- National Infrastructures for Research and Technology, Athens 11523, Greece
| | - George Notas
- Laboratory of Experimental Endocrinology, School of Medicine, University of Crete, 71013, Greece
| | - Vangelis Daskalakis
- Department of Chemical Engineering, Cyprus University of Technology, Limassol, Cyprus
| | | | - Christos Α. Panagiotidis
- Laboratory of Pharmacology, School of Pharmacy, Aristotle University of Thessaloniki, Thessaloniki 54124, Greece
| | - Elias Castanas
- Laboratory of Experimental Endocrinology, School of Medicine, University of Crete, 71013, Greece,Corresponding authors.
| | - Marilena Kampa
- Laboratory of Experimental Endocrinology, School of Medicine, University of Crete, 71013, Greece,Corresponding authors.
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16
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Parrish ML, Broaddus RR, Gladden AB. Mechanisms of mutant β-catenin in endometrial cancer progression. Front Oncol 2022; 12:1009345. [PMID: 36248967 PMCID: PMC9556987 DOI: 10.3389/fonc.2022.1009345] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Accepted: 09/15/2022] [Indexed: 11/17/2022] Open
Abstract
Endometrial carcinoma (EC) is the most diagnosed gynecological malignancy in Western countries. Both incidence and mortality rates of EC have steadily risen in recent years. Despite generally favorable prognoses for patients with the endometrioid type of EC, a subset of patients has been identified with decreased progression-free survival. Patients in this group are distinguished from other endometrioid EC patients by the presence of exon 3 hotspot mutations in CTNNB1, the gene encoding for the β-catenin protein. β-catenin is an evolutionarily conserved protein with critical functions in both adherens junctions and Wnt-signaling. The exact mechanism by which exon 3 CTNNB1 mutations drive EC progression is not well understood. Further, the potential contribution of mutant β-catenin to adherens junctions' integrity is not known. Additionally, the magnitude of worsened progression-free survival in patients with CTNNB1 mutations is context dependent, and therefore the importance of this subset of patients can be obscured by improper categorization. This review will examine the history and functions of β-catenin, how these functions may change and drive EC progression in CTNNB1 mutant patients, and the importance of this patient group in the broader context of the disease.
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Affiliation(s)
- Molly L. Parrish
- Department of Pathology and Laboratory Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
- Pathobiology and Translational Science Graduate Program, The University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Russell R. Broaddus
- Department of Pathology and Laboratory Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
- Pathobiology and Translational Science Graduate Program, The University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Andrew B. Gladden
- Department of Pathology and Laboratory Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
- Pathobiology and Translational Science Graduate Program, The University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
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17
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Song J, Liu C, Li B, Liu L, Zeng L, Ye Z, Mao T, Wu W, Hu B. Tunable Cellular Localization and Extensive Cytoskeleton-Interplay of Reflectins. Front Cell Dev Biol 2022; 10:862011. [PMID: 35813206 PMCID: PMC9259870 DOI: 10.3389/fcell.2022.862011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Accepted: 05/09/2022] [Indexed: 11/13/2022] Open
Abstract
Reflectin proteins are natural copolymers consisting of repeated canonical domains. They are located in a biophotonic system called Bragg lamellae and manipulate the dynamic structural coloration of iridocytes. Their biological functions are intriguing, but the underlying mechanism is not fully understood. Reflectin A1, A2, B1, and C were found to present distinguished cyto-/nucleoplasmic localization preferences in the work. Comparable intracellular localization was reproduced by truncated reflectin variants, suggesting a conceivable evolutionary order among reflectin proteins. The size-dependent access of reflectin variants into the nucleus demonstrated a potential model of how reflectins get into Bragg lamellae. Moreover, RfA1 was found to extensively interact with the cytoskeleton, including its binding to actin and enrichment at the microtubule organizing center. This implied that the cytoskeleton system plays a fundamental role during the organization and transportation of reflectin proteins. The findings presented here provide evidence to get an in-depth insight into the evolutionary processes and working mechanisms of reflectins, as well as novel molecular tools to achieve tunable intracellular transportation.
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Affiliation(s)
- Junyi Song
- College of Liberal Arts Science, National University of Defense Technology, Changsha, China
| | - Chuanyang Liu
- College of Liberal Arts Science, National University of Defense Technology, Changsha, China
| | - Baoshan Li
- College of Liberal Arts Science, National University of Defense Technology, Changsha, China
| | - Liangcheng Liu
- College of Liberal Arts Science, National University of Defense Technology, Changsha, China
| | - Ling Zeng
- College of Liberal Arts Science, National University of Defense Technology, Changsha, China
| | - Zonghuang Ye
- College of Liberal Arts Science, National University of Defense Technology, Changsha, China
| | - Ting Mao
- Logistics Center, National University of Defense Technology, Changsha, China
| | - Wenjian Wu
- College of Liberal Arts Science, National University of Defense Technology, Changsha, China
| | - Biru Hu
- College of Liberal Arts Science, National University of Defense Technology, Changsha, China
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18
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Holzer G, Antonin W. Nup50 plays more than one instrument. Cell Cycle 2022; 21:1785-1794. [PMID: 35549614 PMCID: PMC9359400 DOI: 10.1080/15384101.2022.2074742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Nup50 is nuclear pore complex component localized to the nuclear side of the pore and in the nucleoplasm. It has been characterized as an auxiliary factor in nuclear transport reactions. Our recent work indicates that it interacts with and stimulates RCC1, the sole guanine nucleotide exchange factor for the GTPase Ran. Here, we discuss how this interaction might contribute to Nup50 function in nuclear transport but also its other functions like control of gene expression, cell cycle and DNA damage repair.
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Affiliation(s)
- Guillaume Holzer
- Institute of Biochemistry and Molecular Cell Biology, Medical School, RWTH Aachen University, Aachen, Germany
| | - Wolfram Antonin
- Institute of Biochemistry and Molecular Cell Biology, Medical School, RWTH Aachen University, Aachen, Germany
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19
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Mosevitsky MI. Progerin and Its Role in Accelerated and Natural Aging. Mol Biol 2022. [DOI: 10.1134/s0026893322020091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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20
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Kumar AV, Kang T, Thakurta TG, Ng C, Rogers AN, Larsen MR, Lapierre LR. Exportin 1 modulates life span by regulating nucleolar dynamics via the autophagy protein LGG-1/GABARAP. SCIENCE ADVANCES 2022; 8:eabj1604. [PMID: 35363528 PMCID: PMC10938577 DOI: 10.1126/sciadv.abj1604] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Accepted: 02/08/2022] [Indexed: 06/14/2023]
Abstract
Altered nucleolar and ribosomal dynamics are key hallmarks of aging, but their regulation remains unclear. Building on the knowledge that the conserved nuclear export receptor Exportin 1 (XPO-1/XPO1) modulates proteostasis and life span, we systematically analyzed the impact of nuclear export on protein metabolism. Using transcriptomic and subcellular proteomic analyses in nematodes, we demonstrate that XPO-1 modulates the nucleocytoplasmic distribution of key proteins involved in nucleolar dynamics and ribosome function, including fibrillarin (FIB-1/FBL) and RPL-11 (RPL11). Silencing xpo-1 led to marked reduction in global translation, which was accompanied by decreased nucleolar size and lower fibrillarin levels. A targeted screen of known proteostatic mediators revealed that the autophagy protein LGG-1/GABARAP modulates nucleolar size by regulating RPL-11 levels, linking specific protein degradation to ribosome metabolism. Together, our study reveals that nucleolar size and life span are regulated by LGG-1/GABARAP via ribosome protein surveillance.
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Affiliation(s)
- Anita V. Kumar
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, 185 Meeting St., Providence, RI 02912, USA
| | - Taewook Kang
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
| | - Tara G. Thakurta
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, 185 Meeting St., Providence, RI 02912, USA
| | - Celeste Ng
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, 185 Meeting St., Providence, RI 02912, USA
| | - Aric N. Rogers
- MDI Biological Laboratory, 159 Old Bar Harbor Rd., Salisbury Cove, ME 04672, USA
| | - Martin R. Larsen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
| | - Louis R. Lapierre
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, 185 Meeting St., Providence, RI 02912, USA
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21
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Jameson N, Gavagan M, Zalatan JG. A kinetic mechanism for systems-level behavior in GTPase signaling. Trends Biochem Sci 2022; 47:459-460. [DOI: 10.1016/j.tibs.2022.01.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 01/28/2022] [Accepted: 01/28/2022] [Indexed: 10/19/2022]
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22
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Sule A, Golding SE, Ahmad SF, Watson J, Ahmed MH, Kellogg GE, Bernas T, Koebley S, Reed JC, Povirk LF, Valerie K. ATM phosphorylates PP2A subunit A resulting in nuclear export and spatiotemporal regulation of the DNA damage response. Cell Mol Life Sci 2022; 79:603. [PMID: 36434396 PMCID: PMC9700600 DOI: 10.1007/s00018-022-04550-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2022] [Revised: 08/30/2022] [Accepted: 09/07/2022] [Indexed: 11/26/2022]
Abstract
Ataxia telangiectasia mutated (ATM) is a serine-threonine protein kinase and important regulator of the DNA damage response (DDR). One critical ATM target is the structural subunit A (PR65-S401) of protein phosphatase 2A (PP2A), known to regulate diverse cellular processes such as mitosis and cell growth as well as dephosphorylating many proteins during the recovery from the DDR. We generated mouse embryonic fibroblasts expressing PR65-WT, -S401A (cannot be phosphorylated), and -S401D (phospho-mimetic) transgenes. Significantly, S401 mutants exhibited extensive chromosomal aberrations, impaired DNA double-strand break (DSB) repair and underwent increased mitotic catastrophe after radiation. Both S401A and the S401D cells showed impaired DSB repair (nonhomologous end joining and homologous recombination repair) and exhibited delayed DNA damage recovery, which was reflected in reduced radiation survival. Furthermore, S401D cells displayed increased ERK and AKT signaling resulting in enhanced growth rate further underscoring the multiple roles ATM-PP2A signaling plays in regulating prosurvival responses. Time-lapse video and cellular localization experiments showed that PR65 was exported to the cytoplasm after radiation by CRM1, a nuclear export protein, in line with the very rapid pleiotropic effects observed. A putative nuclear export sequence (NES) close to S401 was identified and when mutated resulted in aberrant PR65 shuttling. Our study demonstrates that the phosphorylation of a single, critical PR65 amino acid (S401) by ATM fundamentally controls the DDR, and balances DSB repair quality, cell survival and growth by spatiotemporal PR65 nuclear-cytoplasmic shuttling mediated by the nuclear export receptor CRM1.
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Affiliation(s)
- Amrita Sule
- Department of Radiation Oncology, Virginia Commonwealth University, Richmond, VA, 23298-0058, USA
- Department of Biochemistry and Molecular Biology, Virginia Commonwealth University, Richmond, VA, 23298, USA
| | - Sarah E Golding
- Department of Radiation Oncology, Virginia Commonwealth University, Richmond, VA, 23298-0058, USA
| | - Syed F Ahmad
- Department of Radiation Oncology, Virginia Commonwealth University, Richmond, VA, 23298-0058, USA
- Department of Biochemistry and Molecular Biology, Virginia Commonwealth University, Richmond, VA, 23298, USA
| | - James Watson
- Department of Radiation Oncology, Virginia Commonwealth University, Richmond, VA, 23298-0058, USA
| | - Mostafa H Ahmed
- Department of Medicinal Chemistry, Virginia Commonwealth University, Richmond, VA, 23298, USA
| | - Glen E Kellogg
- Department of Medicinal Chemistry, Virginia Commonwealth University, Richmond, VA, 23298, USA
- Massey Cancer Center, Virginia Commonwealth University, Richmond, VA, 23298, USA
| | - Tytus Bernas
- Department of Anatomy, Virginia Commonwealth University, Richmond, VA, 23298, USA
| | - Sean Koebley
- Department of Physics, Virginia Commonwealth University, Richmond, VA, 23298, USA
| | - Jason C Reed
- Department of Physics, Virginia Commonwealth University, Richmond, VA, 23298, USA
- Massey Cancer Center, Virginia Commonwealth University, Richmond, VA, 23298, USA
| | - Lawrence F Povirk
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA, 23298, USA
- Massey Cancer Center, Virginia Commonwealth University, Richmond, VA, 23298, USA
| | - Kristoffer Valerie
- Department of Radiation Oncology, Virginia Commonwealth University, Richmond, VA, 23298-0058, USA.
- Department of Biochemistry and Molecular Biology, Virginia Commonwealth University, Richmond, VA, 23298, USA.
- Massey Cancer Center, Virginia Commonwealth University, Richmond, VA, 23298, USA.
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23
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Galinski B, Alexander TB, Mitchell DA, Chatwin HV, Awah C, Green AL, Weiser DA. Therapeutic Targeting of Exportin-1 in Childhood Cancer. Cancers (Basel) 2021; 13:6161. [PMID: 34944778 PMCID: PMC8699059 DOI: 10.3390/cancers13246161] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 11/16/2021] [Accepted: 12/01/2021] [Indexed: 01/24/2023] Open
Abstract
Overexpression of Exportin-1 (XPO1), a key regulator of nuclear-to-cytoplasmic transport, is associated with inferior patient outcomes across a range of adult malignancies. Targeting XPO1 with selinexor has demonstrated promising results in clinical trials, leading to FDA approval of its use for multiple relapsed/refractory cancers. However, XPO1 biology and selinexor sensitivity in childhood cancer is only recently being explored. In this review, we will focus on the differential biology of childhood and adult cancers as it relates to XPO1 and key cargo proteins. We will further explore the current state of pre-clinical and clinical development of XPO1 inhibitors in childhood cancers. Finally, we will outline potentially promising future therapeutic strategies for, as well as potential challenges to, integrating XPO1 inhibition to improve outcomes for children with cancer.
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Affiliation(s)
- Basia Galinski
- Department of Pediatrics, Albert Einstein College of Medicine, Bronx, NY 10461, USA; (B.G.); (D.A.M.); (C.A.)
| | - Thomas B. Alexander
- Department of Pediatrics, University of North Carolina, Chapel Hill, NC 27599, USA;
| | - Daniel A. Mitchell
- Department of Pediatrics, Albert Einstein College of Medicine, Bronx, NY 10461, USA; (B.G.); (D.A.M.); (C.A.)
| | - Hannah V. Chatwin
- Morgan Adams Foundation Pediatric Brain Tumor Research Program, University of Colorado School of Medicine, Aurora, CO 80045, USA;
| | - Chidiebere Awah
- Department of Pediatrics, Albert Einstein College of Medicine, Bronx, NY 10461, USA; (B.G.); (D.A.M.); (C.A.)
| | - Adam L. Green
- Morgan Adams Foundation Pediatric Brain Tumor Research Program, University of Colorado School of Medicine, Aurora, CO 80045, USA;
| | - Daniel A. Weiser
- Department of Pediatrics, Albert Einstein College of Medicine, Bronx, NY 10461, USA; (B.G.); (D.A.M.); (C.A.)
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24
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Vanneste J, Van Den Bosch L. The Role of Nucleocytoplasmic Transport Defects in Amyotrophic Lateral Sclerosis. Int J Mol Sci 2021; 22:12175. [PMID: 34830069 PMCID: PMC8620263 DOI: 10.3390/ijms222212175] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 10/10/2021] [Accepted: 10/14/2021] [Indexed: 12/24/2022] Open
Abstract
There is ample evidence that nucleocytoplasmic-transport deficits could play an important role in the pathology of amyotrophic lateral sclerosis (ALS). However, the currently available data are often circumstantial and do not fully clarify the exact causal and temporal role of nucleocytoplasmic transport deficits in ALS patients. Gaining this knowledge will be of great significance in order to be able to target therapeutically nucleocytoplasmic transport and/or the proteins involved in this process. The availability of good model systems to study the nucleocytoplasmic transport process in detail will be especially crucial in investigating the effect of different mutations, as well as of other forms of stress. In this review, we discuss the evidence for the involvement of nucleocytoplasmic transport defects in ALS and the methods used to obtain these data. In addition, we provide an overview of the therapeutic strategies which could potentially counteract these defects.
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Affiliation(s)
- Joni Vanneste
- Experimental Neurology, Department of Neurosciences and Leuven Brain Institute (LBI), KU Leuven–University of Leuven, B-3000 Leuven, Belgium;
- Laboratory of Neurobiology, Center for Brain & Disease Research, VIB, B-3000 Leuven, Belgium
| | - Ludo Van Den Bosch
- Experimental Neurology, Department of Neurosciences and Leuven Brain Institute (LBI), KU Leuven–University of Leuven, B-3000 Leuven, Belgium;
- Laboratory of Neurobiology, Center for Brain & Disease Research, VIB, B-3000 Leuven, Belgium
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25
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Nuclear export of the pre-60S ribosomal subunit through single nuclear pores observed in real time. Nat Commun 2021; 12:6211. [PMID: 34707094 PMCID: PMC8551241 DOI: 10.1038/s41467-021-26323-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Accepted: 09/02/2021] [Indexed: 11/08/2022] Open
Abstract
Ribosomal biogenesis has been studied by biochemical, genetic and electron microscopic approaches, but live cell data on the in vivo kinetics are still missing. Here we analyse the export kinetics of the large ribosomal subunit (pre-60S particle) through single NPCs in human cells. We established a stable cell line co-expressing Halo-tagged eIF6 and GFP-fused NTF2 to simultaneously label pre-60S particles and NPCs, respectively. By combining single molecule tracking and super resolution confocal microscopy we visualize the dynamics of single pre-60S particles during export through single NPCs. For export events, maximum particle accumulation is found in the centre of the pore, while unsuccessful export terminates within the nuclear basket. The export has a single rate limiting step and a duration of ∼24 milliseconds. Only about 1/3 of attempted export events are successful. Our results show that the mass flux through a single NPC can reach up to ~125 MDa·s-1 in vivo.
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26
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Afinanisa Q, Cho MK, Seong HA. AMPK Localization: A Key to Differential Energy Regulation. Int J Mol Sci 2021; 22:10921. [PMID: 34681581 PMCID: PMC8535671 DOI: 10.3390/ijms222010921] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Revised: 10/05/2021] [Accepted: 10/07/2021] [Indexed: 11/23/2022] Open
Abstract
As the central node between nutrition signaling input and the metabolic pathway, AMP-activated protein kinase (AMPK) is tightly regulated to maintain energy homeostasis. Subcellular compartmentalization of AMPK is one of the critical regulations that enables AMPK to access proper targets and generate appropriate responses to specific perturbations and different levels of stress. One of the characterized localization mechanisms is RanGTPase-driven CRM1 that recognizes the nuclear export sequence (NES) on the α subunit to translocate AMPK into the cytoplasm. Nuclear localization putatively employs RanGTPase-driven importin that might recognize the nuclear localization signal (NLS) present on the AMPKα2 kinase domain. Nucleo-cytoplasmic shuttling of AMPK is influenced by multiple factors, such as starvation, exercise, heat shock, oxidant, cell density, and circadian rhythm. Tissue-specific localization, which distributes AMPK trimers with different combinations, has also been shown to be vital in maintaining tissue-specific metabolism. Tissue-specific and subcellular distribution of AMPK might be attributed to differences in the expression of the subunit, the stabilization by protein regulators, tissue activity, and the localization of AMPK activators. Considering the importance of AMPK localization in coordinating signaling and metabolism, further research is due to fully elucidate the largely unknown complex mechanism underlying this regulation.
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Affiliation(s)
| | | | - Hyun-A Seong
- Department of Biochemistry, School of Biological Sciences, Chungbuk National University, Cheongju 28644, Korea; (Q.A.); (M.K.C.)
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27
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Nord MS, Bernis C, Carmona S, Garland DC, Travesa A, Forbes DJ. Exportins can inhibit major mitotic assembly events in vitro: membrane fusion, nuclear pore formation, and spindle assembly. Nucleus 2021; 11:178-193. [PMID: 32762441 PMCID: PMC7540616 DOI: 10.1080/19491034.2020.1798093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Xenopus egg extracts are a powerful in vitro tool for studying complex biological processes, including nuclear reconstitution, nuclear membrane and pore assembly, and spindle assembly. Extracts have been further used to demonstrate a moonlighting regulatory role for nuclear import receptors or importins on these cell cycle assembly events. Here we show that exportins can also play a role in these events. Addition of Crm1, Exportin-t, or Exportin-5 decreased nuclear pore assembly in vitro. RanQ69L-GTP, a constitutively active form of RanGTP, ameliorated inhibition. Both Crm1 and Exportin-t inhibited fusion of nuclear membranes, again counteracted by RanQ69L-GTP. In mitotic extracts, Crm1 and Exportin-t negatively impacted spindle assembly. Pulldowns from the extracts using Crm1- or Exportin-t-beads revealed nucleoporins known to be essential for both nuclear pore and spindle assembly, with RanQ69L-GTP decreasing a subset of these target interactions. This study suggests a model where exportins, like importins, can regulate major mitotic assembly events.
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Affiliation(s)
- Matthew S Nord
- Section of Cell and Developmental Biology, Division of Biological Sciences 0347, University of California-San Diego , La Jolla, CA, USA
| | - Cyril Bernis
- Section of Cell and Developmental Biology, Division of Biological Sciences 0347, University of California-San Diego , La Jolla, CA, USA
| | - Sarah Carmona
- Section of Cell and Developmental Biology, Division of Biological Sciences 0347, University of California-San Diego , La Jolla, CA, USA
| | - Dennis C Garland
- Section of Cell and Developmental Biology, Division of Biological Sciences 0347, University of California-San Diego , La Jolla, CA, USA
| | - Anna Travesa
- Section of Cell and Developmental Biology, Division of Biological Sciences 0347, University of California-San Diego , La Jolla, CA, USA
| | - Douglass J Forbes
- Section of Cell and Developmental Biology, Division of Biological Sciences 0347, University of California-San Diego , La Jolla, CA, USA
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Markiewicz Ł, Uśpieński T, Baran B, Niedziółka SM, Niewiadomski P. Xpo7 negatively regulates Hedgehog signaling by exporting Gli2 from the nucleus. Cell Signal 2021; 80:109907. [PMID: 33383157 DOI: 10.1016/j.cellsig.2020.109907] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Revised: 12/22/2020] [Accepted: 12/27/2020] [Indexed: 01/01/2023]
Abstract
Dynamic bidirectional transport between the nucleus and the cytoplasm is critical for the regulation of many transcription factors, whose levels inside the nucleus must be tightly controlled. Efficient shuttling across the nuclear membrane is especially crucial with regard to the Hedgehog (Hh) pathway, where the transcriptional signal depends on the fine balance between the amounts of Gli protein activator and repressor forms in the nucleus. The nuclear export machinery prevents the unchecked nuclear accumulation of Gli proteins, but the mechanistic insight into this process is limited. We show that the atypical exportin Xpo7 functions as a major nuclear export receptor that actively excludes Gli2 from the nucleus and controls the outcome of Hh signaling. We show that Xpo7 interacts with several domains of Gli2 and that this interaction is modulated by SuFu, a key negative regulator of Hh signaling. Our data pave the way for a more complete understanding of the nuclear shuttling of Gli proteins and the regulation of their transcriptional activity.
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Affiliation(s)
- Łukasz Markiewicz
- Laboratory of Molecular and Cellular Signaling, Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097 Warsaw, Poland
| | - Tomasz Uśpieński
- Laboratory of Molecular and Cellular Signaling, Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097 Warsaw, Poland
| | - Brygida Baran
- Laboratory of Molecular and Cellular Signaling, Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097 Warsaw, Poland
| | - Sylwia M Niedziółka
- Laboratory of Molecular and Cellular Signaling, Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097 Warsaw, Poland
| | - Paweł Niewiadomski
- Laboratory of Molecular and Cellular Signaling, Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097 Warsaw, Poland.
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Shaikhqasem A, Schmitt K, Valerius O, Ficner R. Crystal structure of human CRM1, covalently modified by 2-mercaptoethanol on Cys528, in complex with RanGTP. Acta Crystallogr F Struct Biol Commun 2021; 77:70-78. [PMID: 33682791 PMCID: PMC7938638 DOI: 10.1107/s2053230x2100203x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Accepted: 02/21/2021] [Indexed: 11/23/2022] Open
Abstract
CRM1 is a nuclear export receptor that has been intensively targeted over the last decade for the development of antitumor and antiviral drugs. Structural analysis of several inhibitor compounds bound to CRM1 revealed that their mechanism of action relies on the covalent modification of a critical cysteine residue (Cys528 in the human receptor) located in the nuclear export signal-binding cleft. This study presents the crystal structure of human CRM1, covalently modified by 2-mercaptoethanol on Cys528, in complex with RanGTP at 2.58 Å resolution. The results demonstrate that buffer components can interfere with the characterization of cysteine-dependent inhibitor compounds.
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Affiliation(s)
- Alaa Shaikhqasem
- Department for Molecular Structural Biology, Georg-August-Universität Göttingen, Justus-von-Liebig Weg 11, 37077 Göttingen, Germany
| | - Kerstin Schmitt
- Department of Molecular Microbiology and Genetics, Georg-August-Universität Göttingen, Grisebachstrasse 8, 37077 Göttingen, Germany
| | - Oliver Valerius
- Department of Molecular Microbiology and Genetics, Georg-August-Universität Göttingen, Grisebachstrasse 8, 37077 Göttingen, Germany
| | - Ralf Ficner
- Department for Molecular Structural Biology, Georg-August-Universität Göttingen, Justus-von-Liebig Weg 11, 37077 Göttingen, Germany
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30
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Zhu C, Kim SJ, Mooradian A, Wang F, Li Z, Holohan S, Collins PL, Wang K, Guo Z, Hoog J, Ma CX, Oltz EM, Held JM, Shao J. Cancer-associated exportin-6 upregulation inhibits the transcriptionally repressive and anticancer effects of nuclear profilin-1. Cell Rep 2021; 34:108749. [PMID: 33596420 PMCID: PMC8006859 DOI: 10.1016/j.celrep.2021.108749] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2020] [Revised: 12/29/2020] [Accepted: 01/21/2021] [Indexed: 01/22/2023] Open
Abstract
Aberrant expression of nuclear transporters and deregulated subcellular localization of their cargo proteins are emerging as drivers and therapeutic targets of cancer. Here, we present evidence that the nuclear exporter exportin-6 and its cargo profilin-1 constitute a functionally important and frequently deregulated axis in cancer. Exportin-6 upregulation occurs in numerous cancer types and is associated with poor patient survival. Reducing exportin-6 level in breast cancer cells triggers antitumor effects by accumulating nuclear profilin-1. Mechanistically, nuclear profilin-1 interacts with eleven-nineteen-leukemia protein (ENL) within the super elongation complex (SEC) and inhibits the ability of the SEC to drive transcription of numerous pro-cancer genes including MYC. XPO6 and MYC are positively correlated across diverse cancer types including breast cancer. Therapeutically, exportin-6 loss sensitizes breast cancer cells to the bromodomain and extra-terminal (BET) inhibitor JQ1. Thus, exportin-6 upregulation is a previously unrecognized cancer driver event by spatially inhibiting nuclear profilin-1 as a tumor suppressor.
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Affiliation(s)
- Cuige Zhu
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Sun-Joong Kim
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Arshag Mooradian
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Faliang Wang
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Surgical Oncology, The Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou 310052, China
| | - Ziqian Li
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Microbial and Biochemical Pharmacy, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou 510006, China
| | - Sean Holohan
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Patrick L Collins
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Microbial Infection and Immunity, The Ohio State University, Columbus, OH 43210, USA
| | - Keren Wang
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Zhanfang Guo
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Jeremy Hoog
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Cynthia X Ma
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA; Siteman Cancer Center, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Eugene M Oltz
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Microbial Infection and Immunity, The Ohio State University, Columbus, OH 43210, USA
| | - Jason M Held
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA; Siteman Cancer Center, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Jieya Shao
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA; Siteman Cancer Center, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO 63110, USA.
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31
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Panagiotopoulos AA, Polioudaki C, Ntallis SG, Dellis D, Notas G, Panagiotidis CA, Theodoropoulos PA, Castanas E, Kampa M. The sequence [EKRKI(E/R)(K/L/R/S/T)] is a nuclear localization signal for importin 7 binding (NLS7). Biochim Biophys Acta Gen Subj 2021; 1865:129851. [PMID: 33482249 DOI: 10.1016/j.bbagen.2021.129851] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 01/14/2021] [Accepted: 01/14/2021] [Indexed: 12/22/2022]
Abstract
BACKGROUND Nuclear translocation of large proteins is mediated through specific protein carriers, collectively named karyopherins (importins, exportins and adaptor proteins). Cargo proteins are recognized by importins through specific motifs, known as nuclear localization signals (NLS). However, only the NLS recognized by importin α and transportin (M9 NLS) have been identified so far METHODS: An unsupervised in silico approach was used, followed by experimental validation. RESULTS We identified the sequence EKRKI(E/R)(K/L/R/S/T) as an NLS signal for importin 7 recognition. This sequence was validated in the breast cancer cell line T47D, which expresses importin 7. Finally, we verified that importin 7-mediated nuclear protein transport is affected by cargo protein phosphorylation. CONCLUSIONS The NLS sequence for importin 7 was identified and we propose this approach as an identification method of novel specific NLS sequences for β-karyopherin family members. GENERAL SIGNIFICANCE Elucidating the complex relationships of the nuclear transporters and their cargo proteins may help in laying the foundation for the development of novel therapeutics, targeting specific importins, with an immediate translational impact.
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Affiliation(s)
| | - Chara Polioudaki
- Laboratory of Biochemistry, School of Medicine, University of Crete, 71013, Greece
| | - Sotirios G Ntallis
- Laboratory of Pharmacology, School of Pharmacy, Aristotle University of Thessaloniki, Thessaloniki 54124, Greece
| | | | - George Notas
- Laboratory of Experimental Endocrinology, School of Medicine, University of Crete, 71013, Greece
| | - Christos A Panagiotidis
- Laboratory of Pharmacology, School of Pharmacy, Aristotle University of Thessaloniki, Thessaloniki 54124, Greece
| | | | - Elias Castanas
- Laboratory of Experimental Endocrinology, School of Medicine, University of Crete, 71013, Greece.
| | - Marilena Kampa
- Laboratory of Experimental Endocrinology, School of Medicine, University of Crete, 71013, Greece.
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Zhou J, Tan Y, Zhang Y, Tong A, Shen X, Sun X, Jia D, Sun Q. GEF-independent Ran activation shifts a fraction of the protein to the cytoplasm and promotes cell proliferation. MOLECULAR BIOMEDICINE 2020; 1:18. [PMID: 35006421 PMCID: PMC8607414 DOI: 10.1186/s43556-020-00011-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Accepted: 09/29/2020] [Indexed: 02/08/2023] Open
Abstract
Ran (Ras-related nuclear protein) plays several important roles in nucleo-cytoplasmic transport, mitotic spindle formation, nuclear envelope/nuclear pore complex assembly, and other functions in the cytoplasm, as well as in cellular transformation when switched on. Unlike other members of the GTPase superfamily, Ran binds more tightly to GDP than to GTP due to the presence of an auto-inhibitory C-terminal tail. Multiple missense mutations in the C-terminus of Ran occur in cancers, but their biological significance remains unclear. Here, the quantitative GDP/GTP binding preference of four engineered mutations with unstable C-termini was analyzed using a devised mant-GDP dissociation assay. The results showed that the impact of different C-terminal mutations depends on multiple factors. Although these mutants were more GTP-loaded in human cells, they were shown to be more cytoplasmic, and to support nuclear transport with minimally or partially reduced efficiency. Further, several Ran cancer mutants were compromised in autoinhibition, slightly more GTP-bound, more cytoplasmic, and enhanced the proliferation of A549 and HeLa cells in vitro. Thus, our work reveals a new route of Ran activation independent of guanine nucleotide exchange factor (GEF), which may account for the hyper-proliferation induced by Ran cancer mutations.
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Affiliation(s)
- Jinhan Zhou
- Department of Pathology, State Key Laboratory of Biotherapy and Cancer Centre, West China Hospital, Sichuan University and Collaborative Innovation Center of Biotherapy, Chengdu, 610041, China
| | - Yuping Tan
- Department of Pathology, State Key Laboratory of Biotherapy and Cancer Centre, West China Hospital, Sichuan University and Collaborative Innovation Center of Biotherapy, Chengdu, 610041, China
| | - Yuqing Zhang
- Department of Pathology, State Key Laboratory of Biotherapy and Cancer Centre, West China Hospital, Sichuan University and Collaborative Innovation Center of Biotherapy, Chengdu, 610041, China
| | - Aiping Tong
- Department of Pathology, State Key Laboratory of Biotherapy and Cancer Centre, West China Hospital, Sichuan University and Collaborative Innovation Center of Biotherapy, Chengdu, 610041, China
| | - Xiaofei Shen
- Key Laboratory of Birth Defects and Related Diseases of Women and Children, Department of Paediatrics, Division of Neurology, West China Second University Hospital, Sichuan University, Chengdu, 610041, China
| | - Xiaodong Sun
- Department of Pharmacology, West China School of Basic Medical Sciences and Forensic Medicine, Sichuan University, Chengdu, 610041, China
| | - Da Jia
- Key Laboratory of Birth Defects and Related Diseases of Women and Children, Department of Paediatrics, Division of Neurology, West China Second University Hospital, Sichuan University, Chengdu, 610041, China.
| | - Qingxiang Sun
- Department of Pathology, State Key Laboratory of Biotherapy and Cancer Centre, West China Hospital, Sichuan University and Collaborative Innovation Center of Biotherapy, Chengdu, 610041, China.
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The Nuclear Pore Complex and mRNA Export in Cancer. Cancers (Basel) 2020; 13:cancers13010042. [PMID: 33375634 PMCID: PMC7796397 DOI: 10.3390/cancers13010042] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 12/11/2020] [Accepted: 12/22/2020] [Indexed: 02/07/2023] Open
Abstract
Export of mRNAs from the nucleus to the cytoplasm is a key regulatory step in the expression of proteins. mRNAs are transported through the nuclear pore complex (NPC). Export of mRNAs responds to a variety of cellular stimuli and stresses. Revelations of the specific effects elicited by NPC components and associated co-factors provides a molecular basis for the export of selected RNAs, independent of bulk mRNA export. Aberrant RNA export has been observed in primary human cancer specimens. These cargo RNAs encode factors involved in nearly all facets of malignancy. Indeed, the NPC components involved in RNA export as well as the RNA export machinery can be found to be dysregulated, mutated, or impacted by chromosomal translocations in cancer. The basic mechanisms associated with RNA export with relation to export machinery and relevant NPC components are described. Therapeutic strategies targeting this machinery in clinical trials is also discussed. These findings firmly position RNA export as a targetable feature of cancer along with transcription and translation.
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34
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Sankunny M, Eng C. Identification of nuclear export signal in KLLN suggests potential role in proteasomal degradation in cancer cells. Oncotarget 2020; 11:4625-4636. [PMID: 33400740 PMCID: PMC7747863 DOI: 10.18632/oncotarget.27833] [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: 09/30/2020] [Accepted: 11/20/2020] [Indexed: 11/25/2022] Open
Abstract
Germline and somatic promoter hypermethylation of KLLN has been found in diverse heritable and sporadic cancers, respectively. KLLN has many identified tumor suppressor functions, and when first reported, was thought to be exclusively nuclear. Here, we report on KLLN localization in both the nucleus and cytoplasm and the identification of a putative nuclear export signal (NES) sequence. KLLN overexpression in colon and breast cancer cells showed both nuclear and cytoplasmic presence. Inhibition of the CRM1 export pathway increased nuclear sequestration of KLLN, confirming the prediction of an NES sequence. Point mutations introduced in the predicted NES sequence decreased the strength of the NES and increased the nuclear sequestration of KLLN. Contrary to expectations, the transcription regulation and cellular proliferation functions of KLLN were unaffected by increased KLLN nuclear sequestration. Instead, increased nuclear KLLN correlated with increased nuclear sequestration of TRIM25 and decreased inhibitory phosphorylation of MDM2. Computational analysis of The Cancer Genome Atlas (TCGA) dataset showed positive correlation among KLLN, TRIM25 and MDM2 expression; pathway analysis of the common genes downstream of these three genes revealed protein degradation as one of the top canonical pathways. Together, our observations suggest that CRM1 pathway-based nuclear export of KLLN may impact proteasomal degradation.
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Affiliation(s)
- Madhav Sankunny
- Genomic Medicine Institute, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio 44195, USA
| | - Charis Eng
- Genomic Medicine Institute, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio 44195, USA.,Center for Personalized Genetic Healthcare, Cleveland Clinic Community Care and Population Health, Cleveland, Ohio 44195, USA.,Taussig Cancer Institute, Cleveland Clinic, Cleveland, Ohio 44195, USA.,Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, Ohio 44106, USA.,Germline High Risk Focus Group, CASE Comprehensive Cancer Center, Case Western Reserve University, Cleveland, Ohio 44106, USA
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35
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Chang CC, Hsia KC. More than a zip code: global modulation of cellular function by nuclear localization signals. FEBS J 2020; 288:5569-5585. [PMID: 33296547 DOI: 10.1111/febs.15659] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2020] [Revised: 12/03/2020] [Accepted: 12/07/2020] [Indexed: 12/27/2022]
Abstract
Extensive structural and functional studies have been carried out in the field of nucleocytoplasmic transport. Nuclear transport factors, such as Importin-α/-β, recognize nuclear localization signals (NLSs) on cargo, and together with the small GTPase Ran, facilitate their nuclear localization. However, it is now emerging that binding of nuclear transport factors to NLSs not only mediates nuclear transport but also contributes to a variety of cellular functions in eukaryotes. Here, we describe recent advances that reveal how NLSs facilitate diverse cellular functions beyond nuclear transport activity. We review separately NLS-mediated regulatory mechanisms at different levels of biological organization, including (a) assembly of higher-order structures; (b) cellular organelle dynamics; and (c) modulation of cellular stress responses and viral infections. Finally, we provide mechanistic insights into how NLSs can regulate such a broad range of functions via their structural and biochemical properties.
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Affiliation(s)
- Chih-Chia Chang
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
| | - Kuo-Chiang Hsia
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan.,Institute of Biochemistry and Molecular Biology, College of Life Sciences, National Yang-Ming University, Taipei, Taiwan
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36
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Guha S, Bhaumik SR. Viral regulation of mRNA export with potentials for targeted therapy. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2020; 1864:194655. [PMID: 33246183 DOI: 10.1016/j.bbagrm.2020.194655] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 07/04/2020] [Revised: 10/15/2020] [Accepted: 11/05/2020] [Indexed: 12/12/2022]
Abstract
Eukaryotic gene expression begins with transcription in the nucleus to synthesize mRNA (messenger RNA), which is subsequently exported to the cytoplasm for translation to protein. Like transcription and translation, mRNA export is an important regulatory step of eukaryotic gene expression. Various factors are involved in regulating mRNA export, and thus gene expression. Intriguingly, some of these factors interact with viral proteins, and such interactions interfere with mRNA export of the host cell, favoring viral RNA export. Hence, viruses hijack host mRNA export machinery for export of their own RNAs from nucleus to cytoplasm for translation to proteins for viral life cycle, suppressing host mRNA export (and thus host gene expression and immune/antiviral response). Therefore, the molecules that can impair the interactions of these mRNA export factors with viral proteins could emerge as antiviral therapeutic agents to suppress viral RNA transport and enhance host mRNA export, thereby promoting host gene expression and immune response. Thus, there has been a number of studies to understand how virus hijacks mRNA export machinery in suppressing host gene expression and promoting its own RNA export to the cytoplasm for translation to proteins required for viral replication/assembly/life cycle towards developing targeted antiviral therapies, as concisely described here.
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Affiliation(s)
- Shalini Guha
- Department of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, IL 62901, USA
| | - Sukesh R Bhaumik
- Department of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, IL 62901, USA.
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Brito C, Barral DC, Pojo M. Subversion of Ras Small GTPases in Cutaneous Melanoma Aggressiveness. Front Cell Dev Biol 2020; 8:575223. [PMID: 33072757 PMCID: PMC7538714 DOI: 10.3389/fcell.2020.575223] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 08/28/2020] [Indexed: 12/25/2022] Open
Abstract
The rising incidence and mortality rate associated with the metastatic ability of cutaneous melanoma represent a major public health concern. Cutaneous melanoma is one of the most invasive human cancers, but the molecular mechanisms are poorly understood. Moreover, currently available therapies are not efficient in avoiding melanoma lethality. In this context, new biomarkers of prognosis, metastasis, and response to therapy are necessary to better predict the disease outcome. Additionally, the knowledge about the molecular alterations and dysregulated pathways involved in melanoma metastasis may provide new therapeutic targets. Members of the Ras superfamily of small GTPases regulate various essential cellular activities, from signaling to membrane traffic and cytoskeleton dynamics. Therefore, it is not surprising that they are differentially expressed, and their functions subverted in several types of cancer, including melanoma. Indeed, Ras small GTPases were found to regulate melanoma progression and invasion. Hence, a better understanding of the mechanisms regulated by Ras small GTPases that are involved in melanoma tumorigenesis and progression may provide new therapeutic strategies to block these processes. Here, we review the current knowledge on the role of Ras small GTPases in melanoma aggressiveness and the molecular mechanisms involved. Furthermore, we summarize the known involvement of these proteins in melanoma metastasis and how these players influence the response to therapy.
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Affiliation(s)
- Cheila Brito
- Unidade de Investigação em Patobiologia Molecular (UIPM) do Instituto Português de Oncologia de Lisboa Francisco Gentil E.P.E., Lisbon, Portugal
| | - Duarte C Barral
- CEDOC, Faculdade de Ciências Médicas, NOVA Medical School, Universidade NOVA de Lisboa, Lisbon, Portugal
| | - Marta Pojo
- Unidade de Investigação em Patobiologia Molecular (UIPM) do Instituto Português de Oncologia de Lisboa Francisco Gentil E.P.E., Lisbon, Portugal
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Cantu D, Croker D, Shacham S, Tamir S, Dulla C. In vivo KPT-350 treatment decreases cortical hyperexcitability following traumatic brain injury. Brain Inj 2020; 34:1489-1496. [PMID: 32853051 DOI: 10.1080/02699052.2020.1807056] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
PRIMARY OBJECTIVE We tested whether KPT-350, a novel selective inhibitor of nuclear export, could attenuate cortical network hyperexcitability, a major risk factor for developing post-traumatic epilepsy (PTE) following traumatic brain injury (TBI). RESEARCH DESIGN All mice in this study underwent TBI and were subsequently treated with either KPT-350 or vehicle during the post-injury latent period. Half of the animal cohort was used for electrophysiology while the other half was used for immunohistochemical analysis. METHODS AND PROCEDURES TBI was induced using the controlled cortical impact (CCI) model. Cortical network activity was recorded by evoking field potentials from deep layers of the cortex and analyzed using Matlab software. Immunohistochemistry coupled with fluorescence microscopy and Image J analysis detected changes in neuronal and glial markers. MAIN OUTCOMES AND RESULTS KPT-350 attenuated TBI-associated epileptiform activity and restored disrupted input-output responses in cortical brain slices. In vivo KPT-350 treatment reduced the loss of parvalbumin-(+) GABAergic interneurons after CCI but did not significantly change CCI-induced loss of somatostatin-(+) GABAergic interneurons, nor did it reduce reactivity of GFAP and Iba1 glial markers. CONCLUSION KPT-350 can prevent cortical hyperexcitability and reduce the loss of parvalbumin-(+) GABAergic inhibitory neurons, making it a potential therapeutic option for preventing PTE.
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Affiliation(s)
- David Cantu
- Department of Neuroscience, Tufts University School of Medicine , Boston, MA, USA
| | - Danielle Croker
- Department of Neuroscience, Tufts University School of Medicine , Boston, MA, USA
| | | | | | - Chris Dulla
- Department of Neuroscience, Tufts University School of Medicine , Boston, MA, USA
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Targeting nuclear import and export in hematological malignancies. Leukemia 2020; 34:2875-2886. [PMID: 32624581 PMCID: PMC7584478 DOI: 10.1038/s41375-020-0958-y] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 06/25/2020] [Accepted: 06/26/2020] [Indexed: 12/18/2022]
Abstract
The transport of proteins across the nuclear membrane is a highly regulated process, essential for the cell function. This transport is actively mediated by members of the karyopherin family, termed importins, or exportins, depending on the direction of transport. These proteins play an active part in tumorigenesis, through aberrant localization of their cargoes, which include oncogenes, tumor-suppressor genes and mediators of key signal transduction pathways. Overexpression of importins and exportins is reported in many malignancies, with implications in cell growth and viability, differentiation, drug resistance, and tumor microenvironment. Given their broad significance across tumors and pathways, much effort is being put to develop specific inhibitors as a novel anticancer therapeutics. Already, selinexor, a specific inhibitor of exportin-1 (XPO1), is approved for clinical use. This review will focus on the role of importins and exportins in hematological malignancies. We will discuss current preclinical and clinical data on importins and exportins, and demonstrate how our growing understanding of their functions has identified new therapeutic targets.
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Boudhraa Z, Carmona E, Provencher D, Mes-Masson AM. Ran GTPase: A Key Player in Tumor Progression and Metastasis. Front Cell Dev Biol 2020; 8:345. [PMID: 32528950 PMCID: PMC7264121 DOI: 10.3389/fcell.2020.00345] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Accepted: 04/20/2020] [Indexed: 12/14/2022] Open
Abstract
Ran (Ras-related nuclear protein) GTPase is a member of the Ras superfamily. Like all the GTPases, Ran cycles between an active (GTP-bound) and inactive (GDP-bound) state. However, Ran lacks the CAAX motif at its C-terminus, a feature of other small GTPases that ensures a plasma membrane localization, and largely traffics between the nucleus and the cytoplasm. Ran regulates nucleo-cytoplasmic transport of molecules through the nuclear pore complex and controls cell cycle progression through the regulation of microtubule polymerization and mitotic spindle formation. The disruption of Ran expression has been linked to cancer at different levels - from cancer initiation to metastasis. In the present review, we discuss the contribution of Ran in the acquisition of three hallmarks of cancer, namely, proliferative signaling, resistance to apoptosis, and invasion/metastasis, and highlight its prognostic value in cancer patients. In addition, we discuss the use of this GTPase as a therapeutic target in cancer.
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Affiliation(s)
- Zied Boudhraa
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montreal, QC, Canada.,Institut du Cancer de Montréal (ICM), Montreal, QC, Canada
| | - Euridice Carmona
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montreal, QC, Canada.,Institut du Cancer de Montréal (ICM), Montreal, QC, Canada
| | - Diane Provencher
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montreal, QC, Canada.,Institut du Cancer de Montréal (ICM), Montreal, QC, Canada.,Division of Gynecologic Oncology, Université de Montréal, Montreal, QC, Canada
| | - Anne-Marie Mes-Masson
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montreal, QC, Canada.,Institut du Cancer de Montréal (ICM), Montreal, QC, Canada.,Department of Medicine, Université de Montréal, Montreal, QC, Canada
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Bishop PJ, Kinoshita Y, Lopes NN, Ward AS, Kohtz DS. Changes in Nup62 content affect contact-induced differentiation of cultured myoblasts. Differentiation 2020; 114:27-35. [PMID: 32554220 DOI: 10.1016/j.diff.2020.05.001] [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: 10/01/2019] [Revised: 03/21/2020] [Accepted: 05/11/2020] [Indexed: 10/24/2022]
Abstract
Differentiation of cultured skeletal myoblasts is induced by extrinsic signals that include reduction in ambient mitogen concentration and increased cell density. Using an established murine myoblast cell line (C2C12), we have found that experimental reduction of the nucleoporin p62 (Nup62) content of myoblasts enhances differentiation in high-mitogen medium, while forced expression of Nup62 inhibits density-induced differentiation. In contrast, differentiation of myoblasts induced by low-mitogen medium was unaffected by ectopic Nup62 expression. Further analyses suggested that Nup62 content affects density-induced myoblast differentiation through a mechanism involving activation of p38 MAP kinase. Nuclear pore complex (NPC) composition, in particular changes in NUP62 content, may be altered during viral infection, differentiation, and in neoplastic growth. The results support a functional role for changes in Nup62 composition in NPCs and density-induced myogenic differentiation, and suggest a link between loss of Nup62 content and induction of an intracellular stress signaling pathways.
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Affiliation(s)
- Patrick J Bishop
- Foundational Sciences, College of Medicine, Central Michigan University, Mount Pleasant, MI, 48859, USA.
| | - Yayoi Kinoshita
- Department of Pathology, Icahn School of Medicine, One Gustave Levy Place, New York, NY, 10029, USA.
| | - N Natalie Lopes
- Foundational Sciences, College of Medicine, Central Michigan University, Mount Pleasant, MI, 48859, USA.
| | - Avery S Ward
- Foundational Sciences, College of Medicine, Central Michigan University, Mount Pleasant, MI, 48859, USA.
| | - D Stave Kohtz
- Foundational Sciences, College of Medicine, Central Michigan University, Mount Pleasant, MI, 48859, USA.
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Mudumbi KC, Czapiewski R, Ruba A, Junod SL, Li Y, Luo W, Ngo C, Ospina V, Schirmer EC, Yang W. Nucleoplasmic signals promote directed transmembrane protein import simultaneously via multiple channels of nuclear pores. Nat Commun 2020; 11:2184. [PMID: 32366843 PMCID: PMC7198523 DOI: 10.1038/s41467-020-16033-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Accepted: 04/09/2020] [Indexed: 02/07/2023] Open
Abstract
Roughly 10% of eukaryotic transmembrane proteins are found on the nuclear membrane, yet how such proteins target and translocate to the nucleus remains in dispute. Most models propose transport through the nuclear pore complexes, but a central outstanding question is whether transit occurs through their central or peripheral channels. Using live-cell high-speed super-resolution single-molecule microscopy we could distinguish protein translocation through the central and peripheral channels, finding that most inner nuclear membrane proteins use only the peripheral channels, but some apparently extend intrinsically disordered domains containing nuclear localization signals into the central channel for directed nuclear transport. These nucleoplasmic signals are critical for central channel transport as their mutation blocks use of the central channels; however, the mutated proteins can still complete their translocation using only the peripheral channels, albeit at a reduced rate. Such proteins can still translocate using only the peripheral channels when central channel is blocked, but blocking the peripheral channels blocks translocation through both channels. This suggests that peripheral channel transport is the default mechanism that was adapted in evolution to include aspects of receptor-mediated central channel transport for directed trafficking of certain membrane proteins.
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Affiliation(s)
- Krishna C Mudumbi
- Department of Biology, Temple University, Philadelphia, PA, 19122, USA.
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT, 06520, USA.
- Yale Cancer Biology Institute, Yale University, West Haven, CT, 06516, USA.
| | - Rafal Czapiewski
- The Institute of Cell Biology, University of Edinburgh, Edinburgh, EH9 3BF, UK
| | - Andrew Ruba
- Department of Biology, Temple University, Philadelphia, PA, 19122, USA
| | - Samuel L Junod
- Department of Biology, Temple University, Philadelphia, PA, 19122, USA
| | - Yichen Li
- Department of Biology, Temple University, Philadelphia, PA, 19122, USA
| | - Wangxi Luo
- Department of Biology, Temple University, Philadelphia, PA, 19122, USA
| | - Christina Ngo
- Department of Biology, Temple University, Philadelphia, PA, 19122, USA
| | - Valentina Ospina
- Department of Biology, Temple University, Philadelphia, PA, 19122, USA
| | - Eric C Schirmer
- The Institute of Cell Biology, University of Edinburgh, Edinburgh, EH9 3BF, UK.
| | - Weidong Yang
- Department of Biology, Temple University, Philadelphia, PA, 19122, USA.
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XPO5 promotes primary miRNA processing independently of RanGTP. Nat Commun 2020; 11:1845. [PMID: 32296071 PMCID: PMC7160132 DOI: 10.1038/s41467-020-15598-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Accepted: 03/17/2020] [Indexed: 12/24/2022] Open
Abstract
XPO5 mediates nuclear export of miRNA precursors in a RanGTP-dependent manner. However, XPO5-associated RNA species have not been determined globally and it is unclear whether XPO5 has any additional functions other than nuclear export. Here we show XPO5 pervasively binds to double-stranded RNA regions found in some clustered primary miRNA precursors and many cellular RNAs. Surprisingly, the binding of XPO5 to pri-miRNAs such as mir-17~92 and mir-15b~16-2 and highly structured RNAs such as vault RNAs is RanGTP-independent. Importantly, XPO5 enhances the processing efficiency of pri-mir-19a and mir-15b~16-2 by the DROSHA/DGCR8 microprocessor. Genetic deletion of XPO5 compromises the biogenesis of most miRNAs and leads to severe defects during mouse embryonic development and skin morphogenesis. This study reveals an unexpected function of XPO5 for recognizing and facilitating the nuclear cleavage of clustered pri-miRNAs, identifies numerous cellular RNAs bound by XPO5, and demonstrates physiological functions of XPO5 in mouse development. XPO5 mediates nuclear export of miRNA hairpin precursors (pre-miRNAs) through a RanGTP-dependent binding. Here the authors employ HITS-CLIP and biochemical analysis and show that XPO5 binds and promotes nuclear processing of clustered pri-miRNAs, with extensive double-stranded regions, independently of RanGTP.
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Abstract
The Ran pathway has a well-described function in nucleocytoplasmic transport, where active Ran dissociates importin/karyopherin-bound cargo containing a nuclear localization signal (NLS) in the nucleus. As cells enter mitosis, the nuclear envelope breaks down and a gradient of active Ran forms where levels are highest near chromatin. This gradient plays a crucial role in regulating mitotic spindle assembly, where active Ran binds to and releases importins from NLS-containing spindle assembly factors. An emerging theme is that the Ran gradient also regulates the actomyosin cortex for processes including polar body extrusion during meiosis, and cytokinesis. For these events, active Ran could play an inhibitory role, where importin-binding may help promote or stabilize a conformation or interaction that favours the recruitment and function of cortical regulators. For either spindle assembly or cortical polarity, the gradient of active Ran determines the extent of importin-binding, the effects of which could vary for different proteins.
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Affiliation(s)
- Imge Ozugergin
- Department of Biology, Concordia University, Montreal, QC, Canada
| | - Alisa Piekny
- Department of Biology, Concordia University, Montreal, QC, Canada
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Gong L, Wen T, Li Z, Wang Y, Wang J, Che X, Liu Y, Qu X. TNPO2 operates downstream of DYNC1I1 and promotes gastric cancer cell proliferation and inhibits apoptosis. Cancer Med 2019; 8:7299-7312. [PMID: 31605449 PMCID: PMC6885870 DOI: 10.1002/cam4.2582] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Revised: 09/11/2019] [Accepted: 09/15/2019] [Indexed: 12/19/2022] Open
Abstract
The import of proteins into the nucleus plays an important role in tumor development. In addition to the classical nuclear import proteins importin-β and importin-α, there are many nonclassical nuclear import proteins that include TNPO2. The role of TNPO2 as a nonclassical nuclear import protein in tumors is limited. Our previous studies have shown that DYNC1I1 is a poor prognostic factor for gastric cancer and can promote the proliferation and metastasis of gastric cancer cells. An expression profile chip showed that TNPO2 was its potential downstream. DYNC1I1 upregulated TNPO2 expression by upregulating SP1, following which, SP1 recruited and bound to the P300-acetylated TNPO2 promoter region histones, and thus promoted TNPO2 expression. At the same time, TNPO2 promoted gastric cancer cell proliferation and inhibited apoptosis by a mechanism that might be depending on the functional expression of P21.
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Affiliation(s)
- Libao Gong
- Department of Medical OncologyThe First Hospital of China Medical UniversityShenyangChina
- Key Laboratory of Anticancer Drugs and Biotherapy of Liaoning ProvinceThe First Hospital of China Medical UniversityShenyangChina
| | - Ti Wen
- Department of Medical OncologyThe First Hospital of China Medical UniversityShenyangChina
- Key Laboratory of Anticancer Drugs and Biotherapy of Liaoning ProvinceThe First Hospital of China Medical UniversityShenyangChina
| | - Zhi Li
- Department of Medical OncologyThe First Hospital of China Medical UniversityShenyangChina
- Key Laboratory of Anticancer Drugs and Biotherapy of Liaoning ProvinceThe First Hospital of China Medical UniversityShenyangChina
| | - Yizhe Wang
- Department of Medical OncologyThe First Hospital of China Medical UniversityShenyangChina
- Key Laboratory of Anticancer Drugs and Biotherapy of Liaoning ProvinceThe First Hospital of China Medical UniversityShenyangChina
| | - Jin Wang
- Department of Medical OncologyThe First Hospital of China Medical UniversityShenyangChina
- Key Laboratory of Anticancer Drugs and Biotherapy of Liaoning ProvinceThe First Hospital of China Medical UniversityShenyangChina
| | - Xiaofang Che
- Department of Medical OncologyThe First Hospital of China Medical UniversityShenyangChina
- Key Laboratory of Anticancer Drugs and Biotherapy of Liaoning ProvinceThe First Hospital of China Medical UniversityShenyangChina
| | - Yunpeng Liu
- Department of Medical OncologyThe First Hospital of China Medical UniversityShenyangChina
- Key Laboratory of Anticancer Drugs and Biotherapy of Liaoning ProvinceThe First Hospital of China Medical UniversityShenyangChina
| | - Xiujuan Qu
- Department of Medical OncologyThe First Hospital of China Medical UniversityShenyangChina
- Key Laboratory of Anticancer Drugs and Biotherapy of Liaoning ProvinceThe First Hospital of China Medical UniversityShenyangChina
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46
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Ernst S, Müller-Newen G. Nucleocytoplasmic Shuttling of STATs. A Target for Intervention? Cancers (Basel) 2019; 11:cancers11111815. [PMID: 31752278 PMCID: PMC6895884 DOI: 10.3390/cancers11111815] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Revised: 11/08/2019] [Accepted: 11/13/2019] [Indexed: 12/12/2022] Open
Abstract
Signal transducer and activator of transcription (STAT) proteins are transcription factors that in the latent state are located predominantly in the cytoplasm. Activation of STATs through phosphorylation of a single tyrosine residue results in nuclear translocation. The requirement of tyrosine phosphorylation for nuclear accumulation is shared by all STAT family members but mechanisms of nuclear translocation vary between different STATs. These differences offer opportunities for specific intervention. To achieve this, the molecular mechanisms of nucleocytoplasmic shuttling of STATs need to be understood in more detail. In this review we will give an overview on the various aspects of nucleocytoplasmic shuttling of latent and activated STATs with a special focus on STAT3 and STAT5. Potential targets for cancer treatment will be identified and discussed.
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Affiliation(s)
- Sabrina Ernst
- Institute of Biochemistry and Molecular Biology, RWTH Aachen University, 52074 Aachen, Germany;
- Confocal Microscopy Facility, Interdisciplinary Center for Clinical Research IZKF, RWTH Aachen University, 52074 Aachen, Germany
| | - Gerhard Müller-Newen
- Institute of Biochemistry and Molecular Biology, RWTH Aachen University, 52074 Aachen, Germany;
- Correspondence:
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47
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Depping R, von Fallois M, Landesman Y, Kosyna FK. The Nuclear Export Inhibitor Selinexor Inhibits Hypoxia Signaling Pathways And 3D Spheroid Growth Of Cancer Cells. Onco Targets Ther 2019; 12:8387-8399. [PMID: 31632086 PMCID: PMC6793465 DOI: 10.2147/ott.s213208] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Accepted: 09/11/2019] [Indexed: 12/17/2022] Open
Abstract
Purpose The nucleocytoplasmic transport of macromolecules is critical for both cell physiology and pathophysiology. Exportin 1 (XPO1), the major nuclear export receptor, is involved in the cellular adaptation to reduced oxygen availability by controlling the nuclear activity of the hypoxia-inducible factors (HIFs). Recently, a specific inhibitor of XPO1, selinexor (KPT-330), has been identified that inhibits nuclear export of cargo proteins by binding to the XPO1 cargo-binding pocket. Patients and methods We used different cancer cell lines from human tissues and evaluated the physiological activity of selinexor on the hypoxia response pathway in two-dimensional (2D) monolayer cell cultures in quantitative real-time (qRT)-PCR experiments and luciferase reporter gene assays. A three-dimensional (3D) tumor spheroid culture model of MCF-7 breast cancer cells was established to analyze the effect of selinexor on 3D tumor spheroid structure, formation and viability. Results Selinexor treatment reduces HIF-transcriptional activity and expression of the HIF-1 target gene solute carrier family 2 member 1 (SLC2A1). Moreover, 3D tumor spheroid structure, formation and viability are inhibited in response to selinexor-induced nuclear export inhibition. Conclusion Here, we demonstrate the effect of specific XPO1-inhibition on the hypoxic response on the molecular level in 2D and 3D culture models of MCF-7 cells.
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Affiliation(s)
- Reinhard Depping
- Center for Structural and Cell Biology in Medicine, Institute of Physiology, Working Group Hypoxia, University of Lübeck, Lübeck D-23562, Germany
| | - Moritz von Fallois
- Center for Structural and Cell Biology in Medicine, Institute of Physiology, Working Group Hypoxia, University of Lübeck, Lübeck D-23562, Germany.,Clinic for Radiotherapy, University Hospital Schleswig-Holstein, Lübeck D-23562, Germany
| | | | - Friederike Katharina Kosyna
- Center for Structural and Cell Biology in Medicine, Institute of Physiology, Working Group Hypoxia, University of Lübeck, Lübeck D-23562, Germany
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48
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Yao L, Zhou Y, Sui Z, Zhang Y, Liu Y, Xie H, Gao H, Fan H, Zhang Y, Liu M, Li S, Tang H. HBV-encoded miR-2 functions as an oncogene by downregulating TRIM35 but upregulating RAN in liver cancer cells. EBioMedicine 2019; 48:117-129. [PMID: 31530503 PMCID: PMC6838411 DOI: 10.1016/j.ebiom.2019.09.012] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 08/24/2019] [Accepted: 09/06/2019] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Hepatitis B virus (HBV) infection has been well established as a high-risk factor for the carcinogenesis of hepatocellular carcinoma (HCC). Cellular microRNA (miRNA) is involved in tumorigenesis by accelerating the malignant phenotype in HCC. However, whether HBV can encode miRNAs that contribute to HCC is not entirely clear. METHODS In this study, an miRNA encoded by HBV (HBV-miR-2) was identified by Solexa sequencing in HBV-positive HCC specimens and further verified in serum samples from HCC patients with HBV infection and in HBV-positive HCC cell lines. To evaluate the roles of HBV-miR-2 in liver cancer cells, we determined cell viability and migration/invasion ability by gain-of-function experiment in HBV(-) liver cancer cells (HepG2 and Huh7) and loss-of-function experiments in Huh7 cells stably expressing HBV-miR-2 (Huh7/HBV-miR-2 cells) and HepG2.2.15 cells. Furthermore, to elucidate the mechanism by which HBV-miR-2 work on cell malignancy, we identified and studied the effect of two target genes (TRIM35 and RAN) of HBV-miR-2 in liver cancer cells. FINDINGS We revealed that HBV-miR-2 promoted HCC cell growth ability by suppressing apoptosis and promoting migration and invasion by enhancing the epithelial-mesenchymal transition (EMT), functioning as an oncogene in the development of HBV-related HCC. Furthermore, we demonstrated that HBV-miR-2 suppresses the expression of TRIM35 but enhances RAN expression by targeting their 3'-untranslated regions (3'UTR) and that the ectopic expression of TRIM35 or knockdown of RAN counteracted the malignant phenotypes induced by HBV-miR-2. INTERPRETATION Our findings indicate that an HBV-encoded miRNA, HBV-miR-2, promotes oncogenic activity by downregulating TRIM35 expression and upregulating RAN expression in liver cancer cells, likely providing insight into tumorigenesis in HBV-related liver cancer. FUND: This work was supported in part by the National Natural Science Foundation of China (No: 81830094; 91629302; 31270818) and the Natural Science Foundation of Tianjin (No: 12JCZDJC25100).
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Affiliation(s)
- Lili Yao
- Tianjin Life Science Research Center, Tianjin Laboratory of Inflammation Biology, Collaborative Innovation Center of Tianjin for Medical Epigenetics, Department of Pathogen Biology, Basic Medical School, Tianjin Medical University, Tianjin 300070, China
| | - Yadi Zhou
- Tianjin Life Science Research Center, Tianjin Laboratory of Inflammation Biology, Collaborative Innovation Center of Tianjin for Medical Epigenetics, Department of Pathogen Biology, Basic Medical School, Tianjin Medical University, Tianjin 300070, China
| | - Zhenhua Sui
- Tianjin Life Science Research Center, Tianjin Laboratory of Inflammation Biology, Collaborative Innovation Center of Tianjin for Medical Epigenetics, Department of Pathogen Biology, Basic Medical School, Tianjin Medical University, Tianjin 300070, China
| | - Yanling Zhang
- Tianjin Life Science Research Center, Tianjin Laboratory of Inflammation Biology, Collaborative Innovation Center of Tianjin for Medical Epigenetics, Department of Pathogen Biology, Basic Medical School, Tianjin Medical University, Tianjin 300070, China
| | - Yankun Liu
- The Cancer Institute, Tangshan People's Hospital, Tangshan 063001, China
| | - Hong Xie
- Tianjin Life Science Research Center, Tianjin Laboratory of Inflammation Biology, Collaborative Innovation Center of Tianjin for Medical Epigenetics, Department of Pathogen Biology, Basic Medical School, Tianjin Medical University, Tianjin 300070, China.
| | - Huijie Gao
- Tianjin Life Science Research Center, Tianjin Laboratory of Inflammation Biology, Collaborative Innovation Center of Tianjin for Medical Epigenetics, Department of Pathogen Biology, Basic Medical School, Tianjin Medical University, Tianjin 300070, China
| | - Hongxia Fan
- Tianjin Life Science Research Center, Tianjin Laboratory of Inflammation Biology, Collaborative Innovation Center of Tianjin for Medical Epigenetics, Department of Pathogen Biology, Basic Medical School, Tianjin Medical University, Tianjin 300070, China
| | - Yi Zhang
- Tianjin Life Science Research Center, Tianjin Laboratory of Inflammation Biology, Collaborative Innovation Center of Tianjin for Medical Epigenetics, Department of Pathogen Biology, Basic Medical School, Tianjin Medical University, Tianjin 300070, China
| | - Min Liu
- Tianjin Life Science Research Center, Tianjin Laboratory of Inflammation Biology, Collaborative Innovation Center of Tianjin for Medical Epigenetics, Department of Pathogen Biology, Basic Medical School, Tianjin Medical University, Tianjin 300070, China
| | - Shengping Li
- State Key Laboratory of Oncology in Southern China, Department of Hepatobiliary Oncology, Cancer Center, Sun Yat-sen University, Guangzhou 510060, China.
| | - Hua Tang
- Tianjin Life Science Research Center, Tianjin Laboratory of Inflammation Biology, Collaborative Innovation Center of Tianjin for Medical Epigenetics, Department of Pathogen Biology, Basic Medical School, Tianjin Medical University, Tianjin 300070, China.
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49
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Xie Y, Ren Y. Mechanisms of nuclear mRNA export: A structural perspective. Traffic 2019; 20:829-840. [PMID: 31513326 DOI: 10.1111/tra.12691] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Accepted: 08/26/2019] [Indexed: 12/28/2022]
Abstract
Export of mRNA from the nucleus to the cytoplasm is a critical process for all eukaryotic gene expression. As mRNA is synthesized, it is packaged with a myriad of RNA-binding proteins to form ribonucleoprotein particles (mRNPs). For each step in the processes of maturation and export, mRNPs must have the correct complement of proteins. Much of the mRNA export pathway revolves around the heterodimeric export receptor yeast Mex67•Mtr2/human NXF1•NXT1, which is recruited to signal the completion of nuclear mRNP assembly, mediates mRNP targeting/translocation through the nuclear pore complex (NPC), and is displaced at the cytoplasmic side of the NPC to release the mRNP into the cytoplasm. Directionality of the transport is governed by at least two DEAD-box ATPases, yeast Sub2/human UAP56 in the nucleus and yeast Dbp5/human DDX19 at the cytoplasmic side of the NPC, which respectively mediate the association and dissociation of Mex67•Mtr2/NXF1•NXT1 onto the mRNP. Here we review recent progress from structural studies of key constituents in different steps of nuclear mRNA export. These findings have laid the foundation for further studies to obtain a comprehensive mechanistic view of the mRNA export pathway.
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Affiliation(s)
- Yihu Xie
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Yi Ren
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee
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50
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Chatzifrangkeskou M, Pefani D, Eyres M, Vendrell I, Fischer R, Pankova D, O'Neill E. RASSF1A is required for the maintenance of nuclear actin levels. EMBO J 2019; 38:e101168. [PMID: 31414556 PMCID: PMC6694222 DOI: 10.15252/embj.2018101168] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Revised: 04/23/2019] [Accepted: 05/14/2019] [Indexed: 01/19/2023] Open
Abstract
Nuclear actin participates in many essential cellular processes including gene transcription, chromatin remodelling and mRNA processing. Actin shuttles into and out the nucleus through the action of dedicated transport receptors importin-9 and exportin-6, but how this transport is regulated remains unclear. Here, we show that RASSF1A is a novel regulator of actin nucleocytoplasmic trafficking and is required for the active maintenance of nuclear actin levels through supporting binding of exportin-6 (XPO6) to RAN GTPase. RASSF1A (Ras association domain family 1 isoform A) is a tumour suppressor gene frequently silenced by promoter hypermethylation in all major solid cancers. Specifically, we demonstrate that endogenous RASSF1A localises to the nuclear envelope (NE) and is required for nucleocytoplasmic actin transport and the concomitant regulation of myocardin-related transcription factor A (MRTF-A), a co-activator of the transcription factor serum response factor (SRF). The RASSF1A/RAN/XPO6/nuclear actin pathway is aberrant in cancer cells where RASSF1A expression is lost and correlates with reduced MRTF-A/SRF activity leading to cell adhesion defects. Taken together, we have identified a previously unknown mechanism by which the nuclear actin pool is regulated and uncovered a previously unknown link of RASSF1A and MRTF-A/SRF in tumour suppression.
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Affiliation(s)
| | - Dafni‐Eleftheria Pefani
- Department of OncologyUniversity of OxfordOxfordUK
- Laboratory of BiologyMedical SchoolNational and Kapodistrian University of AthensAthensGreece
- Biomedical Research Foundation of the Academy of AthensAthensGreece
| | | | - Iolanda Vendrell
- Department of OncologyUniversity of OxfordOxfordUK
- Nuffield Department of MedicineTarget Discovery InstituteUniversity of OxfordOxfordUK
| | - Roman Fischer
- Nuffield Department of MedicineTarget Discovery InstituteUniversity of OxfordOxfordUK
| | | | - Eric O'Neill
- Department of OncologyUniversity of OxfordOxfordUK
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