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Guo Y, Tao T, Wu T, Hou J, Lin W. Nucleoporin Nup98 is an essential factor for ipo4 dependent protein import. J Cell Biochem 2024. [PMID: 38780165 DOI: 10.1002/jcb.30573] [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: 11/16/2023] [Revised: 04/12/2024] [Accepted: 04/19/2024] [Indexed: 05/25/2024]
Abstract
Nucleocytoplasmic transport of macromolecules is essential in eukaryotic cells. In this process, the karyopherins play a central role when they transport cargoes across the nuclear pore complex. Importin 4 belongs to the karyopherin β family. Many studies have focused on finding substrates for importin 4, but no direct mechanism studies of its precise transport function have been reported. Therefore, this paper mainly aimed to study the mechanism of nucleoporins in mediating nuclear import and export of importin 4. To address this question, we constructed shRNAs targeting Nup358, Nup153, Nup98, and Nup50. We found that depletion of Nup98 resulted in a shift in the subcellular localization of importin 4 from the cytoplasm to the nucleus. Mutational analysis demonstrated that Nup98 physically and functionally interacts with importin 4 through its N-terminal phenylalanine-glycine (FG) repeat region. Mutation of nine of these FG motifs to SG motifs significantly attenuated the binding of Nup98 to importin 4, and we further confirmed the essential role of the six FG motifs in amino acids 121-360 of Nup98 in binding with importin 4. In vitro transport assay also confirmed that VDR, the substrate of importin 4, could not be transported into the nucleus after Nup98 knockdown. Overall, our results showed that Nup98 is required for efficient importin 4-mediated transport. This is the first study to reveal the mechanism of importin 4 in transporting substrates into the nucleus.
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Affiliation(s)
- Yingying Guo
- State Key Laboratory of Stress Cell Biology, School of Life Sciences, Xiamen University, Xiame, Fujian, China
| | - Tao Tao
- State Key Laboratory of Stress Cell Biology, School of Life Sciences, Xiamen University, Xiame, Fujian, China
| | - Ting Wu
- Department of Basic Medicine, School of Medicine, Cancer Research Center, Xiamen University, Xiamen, Fujian, China
| | - Jingjing Hou
- State Key Laboratory of Stress Cell Biology, School of Life Sciences, Xiamen University, Xiame, Fujian, China
- Department of Gastrointestinal Surgery, School of Medicine, Zhongshan Hospital of Xiamen University, Xiamen University, Xiamen, Fujian, China
| | - Wenbo Lin
- State Key Laboratory of Stress Cell Biology, School of Life Sciences, Xiamen University, Xiame, Fujian, China
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2
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Bin JM, Suminaite D, Benito-Kwiecinski SK, Kegel L, Rubio-Brotons M, Early JJ, Soong D, Livesey MR, Poole RJ, Lyons DA. Importin 13-dependent axon diameter growth regulates conduction speeds along myelinated CNS axons. Nat Commun 2024; 15:1790. [PMID: 38413580 PMCID: PMC10899189 DOI: 10.1038/s41467-024-45908-6] [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: 06/01/2023] [Accepted: 02/06/2024] [Indexed: 02/29/2024] Open
Abstract
Axon diameter influences the conduction properties of myelinated axons, both directly, and indirectly through effects on myelin. However, we have limited understanding of mechanisms controlling axon diameter growth in the central nervous system, preventing systematic dissection of how manipulating diameter affects myelination and conduction along individual axons. Here we establish zebrafish to study axon diameter. We find that importin 13b is required for axon diameter growth, but does not affect cell body size or axon length. Using neuron-specific ipo13b mutants, we assess how reduced axon diameter affects myelination and conduction, and find no changes to myelin thickness, precision of action potential propagation, or ability to sustain high frequency firing. However, increases in conduction speed that occur along single myelinated axons with development are tightly linked to their growth in diameter. This suggests that axon diameter growth is a major driver of increases in conduction speeds along myelinated axons over time.
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Affiliation(s)
- Jenea M Bin
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH16 4SB, UK.
| | - Daumante Suminaite
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH16 4SB, UK
| | | | - Linde Kegel
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH16 4SB, UK
| | - Maria Rubio-Brotons
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH16 4SB, UK
| | - Jason J Early
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH16 4SB, UK
| | - Daniel Soong
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH16 4SB, UK
| | - Matthew R Livesey
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH16 4SB, UK
- Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield, S10 2HQ, UK
- Neuroscience Institute, University of Sheffield, Sheffield, S10 2TN, UK
| | - Richard J Poole
- Department of Cell and Developmental Biology, University College London, London, WC1E 6BT, UK
| | - David A Lyons
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH16 4SB, UK.
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3
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Xiao Z, Zhang Y, She Y, Yuan G, Yang G. IPO7 promotes lipopolysaccharide-induced inflammatory responses in human dental pulp cells via p38 MAPK and NF-κB signaling pathways. Mol Immunol 2023; 163:116-126. [PMID: 37769576 DOI: 10.1016/j.molimm.2023.09.011] [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: 04/05/2023] [Revised: 07/19/2023] [Accepted: 09/14/2023] [Indexed: 10/03/2023]
Abstract
Pulpitis is a chronic inflammatory process that greatly affects the physical, mental health and life quality of patients. Human dental pulp cells (hDPCs) are essential components of dental pulp tissue and play a significant role in pulpitis. Lipopolysaccharide (LPS) is an initiator of pulpitis and can induce the production of inflammatory cytokines in hDPCs by activating p38 MAPK and NF-κB signaling pathways. Importin7 (IPO7), a member of the importin-β family, is widely expressed in many tissues. Previous studies have shown that IPO7 mediated nuclear translocation of p-p38 after stimulation, and IPO7 homologous protein IPO8 participated in human dental pulp inflammation. This research aims to investigate whether IPO7 is involved in pulpitis and explore its underlying mechanisms. In the current study, we found the expression of IPO7 was increased in pulpitis tissue. In vitro, hDPCs treated with LPS to mimic the inflammatory environment, the expression of IPO7 was increased. Knockdown of IPO7 significantly inhibited the production of inflammatory cytokines and suppressed the p38 MAPK and NF-κB signaling pathways. Activating the p38 MAPK and NF-κB signaling pathways by the p38 activator and p65 activator reversed the inflammatory responses. IPO7 interacted with p-p38 under LPS stimulation in hDPCs. In addition, the increased binding between IPO7 and p-p38 is associated with the decreased binding ability of IPO7 to Sirt2. In conclusion, we found that IPO7 was highly expressed in pulpitis and played a vital role in modulating human dental pulp inflammation.
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Affiliation(s)
- Ziqiu Xiao
- State Key Laboratory of Oral & Maxillofacial Reconstruction and Regeneration, Key Laboratory of Oral Biomedicine Ministry of Education, Hubei Key Laboratory of Stomatology, School & Hospital of Stomatology, Wuhan University
| | - Yue Zhang
- State Key Laboratory of Oral & Maxillofacial Reconstruction and Regeneration, Key Laboratory of Oral Biomedicine Ministry of Education, Hubei Key Laboratory of Stomatology, School & Hospital of Stomatology, Wuhan University
| | - Yawei She
- State Key Laboratory of Oral & Maxillofacial Reconstruction and Regeneration, Key Laboratory of Oral Biomedicine Ministry of Education, Hubei Key Laboratory of Stomatology, School & Hospital of Stomatology, Wuhan University
| | - Guohua Yuan
- State Key Laboratory of Oral & Maxillofacial Reconstruction and Regeneration, Key Laboratory of Oral Biomedicine Ministry of Education, Hubei Key Laboratory of Stomatology, School & Hospital of Stomatology, Wuhan University
| | - Guobin Yang
- State Key Laboratory of Oral & Maxillofacial Reconstruction and Regeneration, Key Laboratory of Oral Biomedicine Ministry of Education, Hubei Key Laboratory of Stomatology, School & Hospital of Stomatology, Wuhan University.
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4
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Wang Y, Xu J, Zhu X, Kuang H. MicroRNA-130a-3p impedes the progression of papillary thyroid carcinoma through downregulation of KPNB1 by targeting PSME3. Endocrine 2023; 82:96-107. [PMID: 37166548 DOI: 10.1007/s12020-023-03383-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Accepted: 04/21/2023] [Indexed: 05/12/2023]
Abstract
BACKGROUND Papillary thyroid carcinoma (PTC) is the main type of thyroid cancer (THCA). Despite the good prognosis, some PTC patients may deteriorate into more aggressive disease, leading to poor survival. Our study aimed to explore the role of microRNA (miR)-130a-3p in regulating PTC. METHODS After transfection with miR-130a-3p-mimic, OE-PSME3, or miR-130a-3p-mimic + OE-KPNB1 in PTC cells (TPC-1), CCK-8, Transwell, scratch, and flow cytometry experiments were performed to analyze TPC-1 cell proliferation, invasion, migration, and apoptosis. Western blotting was used to detect proliferation or invasion-related protein markers (PCNA, E-cadherin, and N-cadherin). The RNA22 database, dual-luciferase reporter assay, and RNA pull-down assay were applied for the prediction and verification of the binding site between miR-130a-3p and PSME3. Pan-cancer software identified a positive correlation between PSME3 and KPNB1 in THCA. Co-immunoprecipitation was utilized to verify the interaction of PSME3 with KPNB1. Nude mice were transplanted with TPC-1 cells overexpressing miR-130a-3p. The tumors were isolated for detection of the expression of miR-130a-3p, PSME3, KPNB1, Ki-67, and CD31. RESULTS miR-130a-3p was lowly expressed in PTC cell lines. Upregulation of miR-130a-3p repressed the expression of PSME3 and KPNB1 and reduced the malignancy of TPC-1 cells in vitro, shown by inhibited cell proliferation, invasion, migration, and the expression of PCNA and N-cadherin. Also, overexpressed miR-130a-3p inhibited the growth of xenograft tumors in nude mice. miR-130a-3p bound to PSME3 which interacted with KPNB1. CONCLUSION miR-130a-3p impedes the progression of PTC by downregulating PSME3/KPNB1.
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Affiliation(s)
- Yan Wang
- Department of Endocrinology, The First Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang, 150001, P.R. China
- Department of Endocrinology, The Fourth Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang, 150001, P.R. China
| | - Jinmei Xu
- Department of Endocrinology, The Fourth Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang, 150001, P.R. China
| | - Xiaodan Zhu
- Department of Endocrinology, The First Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang, 150001, P.R. China
| | - Hongyu Kuang
- Department of Endocrinology, The First Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang, 150001, P.R. China.
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Elsalahaty MI, Salama AF, Diab T, Ghazy M, Toraih E, Elshazli RM. Unleash Multifunctional Role of miRNA Biogenesis Gene Variants ( XPO5*rs34324334 and RAN*rs14035) with Susceptibility to Hepatocellular Carcinoma. J Pers Med 2023; 13:959. [PMID: 37373948 DOI: 10.3390/jpm13060959] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Revised: 06/02/2023] [Accepted: 06/05/2023] [Indexed: 06/29/2023] Open
Abstract
Numerous reports have explored the roles of different genetic variants in miRNA biogenesis mechanisms and the progression of various types of carcinomas. The goal of this study is to explore the association between XPO5*rs34324334 and RAN*rs14035 gene variants and susceptibility to hepatocellular carcinoma (HCC). In a cohort of 234 participants (107 HCC patients and 127 unrelated cancer-free controls) from the same geographic region, we characterized allelic discrimination using PCR-RFLP and performed subgroup analysis and multivariate regression. We found that the frequency of the XPO5*rs34324334 (A) variant was correlated with elevated risk of HCC under allelic (OR = 10.09, p-value < 0.001), recessive (OR = 24.1, p-value < 0.001), and dominant (OR = 10.1, p-value < 0.001) models. A/A genotype was associated with hepatitis C cirrhosis (p-value = 0.012), ascites (p-value = 0.003), and higher levels of alpha-fetoproteins (p-value = 0.011). Carriers of the RAN*rs14035 (T) variant were more likely to develop HCC under allelic (OR = 1.76, p-value = 0.003) and recessive (OR = 3.27, p-value < 0.001) models. Our results suggest that XPO5*rs34324334 and RAN*rs14035 variants are independent risk factors for developing HCC.
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Affiliation(s)
- Mohamed I Elsalahaty
- Biochemistry Division, Department of Chemistry, Faculty of Science, Tanta University, Tanta 31527, Egypt
| | - Afrah F Salama
- Biochemistry Division, Department of Chemistry, Faculty of Science, Tanta University, Tanta 31527, Egypt
| | - Thoria Diab
- Biochemistry Division, Department of Chemistry, Faculty of Science, Tanta University, Tanta 31527, Egypt
| | - Medhat Ghazy
- Department of Internal Medicine, Faculty of Medicine, Tanta University, Tanta 31527, Egypt
| | - Eman Toraih
- Endocrine and Oncology Division, Department of Surgery, School of Medicine, Tulane University, New Orleans, LA 70112, USA
- Department of Histology and Cell Biology, Genetics Unit, Faculty of Medicine, Suez Canal University, Ismailia 41522, Egypt
| | - Rami M Elshazli
- Biochemistry and Molecular Genetics Unit, Department of Basic Sciences, Faculty of Physical Therapy, Horus University-Egypt, New Damietta 34517, Egypt
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Shi J, Pei Y, Yu Q, Dong H. Progress in the study of parvovirus entry pathway. Virol J 2023; 20:61. [PMID: 37016419 PMCID: PMC10072039 DOI: 10.1186/s12985-023-02016-z] [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: 12/27/2022] [Accepted: 03/21/2023] [Indexed: 04/06/2023] Open
Abstract
A group of DNA viruses called parvoviruses that have significant effects on cancer therapy and genetic engineering applications. After passing through the cell membrane to reach the cytosol, it moves along the microtubule toward the nuclear membrane. The nuclear localization signal (NLS) is recognized by importin-beta (impβ) and other proteins from the complex outside the nuclear membrane and binds to enter the nucleus via the nuclear pore complex (NPC). There are two main pathways for viruses to enter the nucleus. The classical pathway is through the interaction of imp α and impβ with NLS via NPC. The other is the NPC mediated by the combination of impβ and it. While the capsid is introduced into the nucleus through classical nuclear transduction, there is also a transient nuclear membrane dissolution leading to passive transport into the nucleus, which has been proposed in recent years. This article mainly discusses several nuclear entry pathways and related proteins, providing a reference for subsequent research on viral entry pathways.
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Affiliation(s)
- Jiuming Shi
- College of Life Sciences, Jilin Agricultural University, Changchun, 130118, Jilin Province, China
| | - Yifeng Pei
- College of Life Sciences, Jilin Agricultural University, Changchun, 130118, Jilin Province, China
| | - Qian Yu
- College of Life Sciences, Jilin Agricultural University, Changchun, 130118, Jilin Province, China
| | - Hao Dong
- College of Life Sciences, Jilin Agricultural University, Changchun, 130118, Jilin Province, China.
- Engineering Research Center of Bioreactor and Pharmaceutical Development, Jilin Agricultural University, Changchun, 130118, China.
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7
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Beachum AN, Hinnant TD, Williams AE, Powell AM, Ables ET. β-importin Tnpo-SR promotes germline stem cell maintenance and oocyte differentiation in female Drosophila. Dev Biol 2023; 494:1-12. [PMID: 36450333 PMCID: PMC9870978 DOI: 10.1016/j.ydbio.2022.11.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 11/09/2022] [Accepted: 11/21/2022] [Indexed: 11/29/2022]
Abstract
Germ cell development requires interplay between factors that balance cell fate and division. Early in their development, germ cells in many organisms divide mitotically with incomplete cytokinesis. Key regulatory events then lead to the specification of mature gametes, marked by the switch to a meiotic cell cycle program. Though the regulation of germ cell proliferation and meiosis are well understood, how these events are coordinated during development remains incompletely described. Originally characterized in their role as nucleo-cytoplasmic shuttling proteins, β-importins exhibit diverse functions during male and female gametogenesis. Here, we describe novel, distinct roles for the β-importin, Transportin-Serine/Arginine rich (Tnpo-SR), as a regulator of the mitosis to meiosis transition in the Drosophila ovary. We find that Tnpo-SR is necessary for germline stem cell (GSC) establishment and self-renewal, likely by controlling the response of GSCs to bone morphogenetic proteins. Depletion of Tnpo-SR results in germ cell counting defects and loss of oocyte identity. We show that in the absence of Tnpo-SR, proteins typically suppressed in germ cells when they exit mitosis fail to be down-regulated, and oocyte-specific factors fail to accumulate. Together, these findings provide new insight into the balance between germ cell division and differentiation and identify novel roles for β-importins in germ cell development.
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Affiliation(s)
- Allison N Beachum
- Department of Biology, East Carolina University, Greenville, NC, 27858, USA
| | - Taylor D Hinnant
- Department of Biology, East Carolina University, Greenville, NC, 27858, USA
| | - Anna E Williams
- Department of Biology, East Carolina University, Greenville, NC, 27858, USA
| | - Amanda M Powell
- Department of Biology, East Carolina University, Greenville, NC, 27858, USA
| | - Elizabeth T Ables
- Department of Biology, East Carolina University, Greenville, NC, 27858, USA.
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8
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Jin L, Zhang G, Yang G, Dong J. Identification of the Karyopherin Superfamily in Maize and Its Functional Cues in Plant Development. Int J Mol Sci 2022; 23:ijms232214103. [PMID: 36430578 PMCID: PMC9699179 DOI: 10.3390/ijms232214103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 11/06/2022] [Accepted: 11/13/2022] [Indexed: 11/18/2022] Open
Abstract
Appropriate nucleo-cytoplasmic partitioning of proteins is a vital regulatory mechanism in phytohormone signaling and plant development. However, how this is achieved remains incompletely understood. The Karyopherin (KAP) superfamily is critical for separating the biological processes in the nucleus from those in the cytoplasm. The KAP superfamily is divided into Importin α (IMPα) and Importin β (IMPβ) families and includes the core components in mediating nucleocytoplasmic transport. Recent reports suggest the KAPs play crucial regulatory roles in Arabidopsis development and stress response by regulating the nucleo-cytoplasmic transport of members in hormone signaling. However, the KAP members and their associated molecular mechanisms are still poorly understood in maize. Therefore, we first identified seven IMPα and twenty-seven IMPβ genes in the maize genome and described their evolution traits and the recognition rules for substrates with nuclear localization signals (NLSs) or nuclear export signals (NESs) in plants. Next, we searched for the protein interaction partners of the ZmKAPs and selected the ones with Arabidopsis orthologs functioning in auxin biosynthesis, transport, and signaling to predict their potential function. Finally, we found that several ZmKAPs share similar expression patterns with their interacting proteins, implying their function in root development. Overall, this article focuses on the Karyopherin superfamily in maize and starts with this entry point by systematically comprehending the KAP-mediated nucleo-cytoplasmic transport process in plants, and then predicts the function of the ZmKAPs during maize development, with a perspective on a closely associated regulatory mechanism between the nucleo-cytoplasmic transport and the phytohormone network.
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Affiliation(s)
- Lu Jin
- The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao 266237, China
| | - Guobin Zhang
- College of Agronomy, Shandong Agricultural University, Taian 271018, China
| | - Guixiao Yang
- The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao 266237, China
| | - Jiaqiang Dong
- The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao 266237, China
- Correspondence:
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Karasev MM, Baloban M, Verkhusha VV, Shcherbakova DM. Nuclear Localization Signals for Optimization of Genetically Encoded Tools in Neurons. Front Cell Dev Biol 2022; 10:931237. [PMID: 35927988 PMCID: PMC9344056 DOI: 10.3389/fcell.2022.931237] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Accepted: 06/24/2022] [Indexed: 12/15/2022] Open
Abstract
Nuclear transport in neurons differs from that in non-neuronal cells. Here we developed a non-opsin optogenetic tool (OT) for the nuclear export of a protein of interest induced by near-infrared (NIR) light. In darkness, nuclear import reverses the OT action. We used this tool for comparative analysis of nuclear transport dynamics mediated by nuclear localization signals (NLSs) with different importin specificities. We found that widely used KPNA2-binding NLSs, such as Myc and SV40, are suboptimal in neurons. We identified uncommon NLSs mediating fast nuclear import and demonstrated that the performance of the OT for nuclear export can be adjusted by varying NLSs. Using these NLSs, we optimized the NIR OT for light-controlled gene expression for lower background and higher contrast in neurons. The selected NLSs binding importins abundant in neurons could improve performance of genetically encoded tools in these cells, including OTs and gene-editing tools.
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Affiliation(s)
- Maksim M. Karasev
- Medicum, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Mikhail Baloban
- Department of Genetics and Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, NY, United States
| | - Vladislav V. Verkhusha
- Medicum, Faculty of Medicine, University of Helsinki, Helsinki, Finland
- Department of Genetics and Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, NY, United States
| | - Daria M. Shcherbakova
- Department of Genetics and Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, NY, United States
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10
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Kalita J, Kapinos LE, Zheng T, Rencurel C, Zilman A, Lim RYH. Karyopherin enrichment and compensation fortifies the nuclear pore complex against nucleocytoplasmic leakage. J Cell Biol 2022; 221:212986. [PMID: 35089308 PMCID: PMC8932525 DOI: 10.1083/jcb.202108107] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 10/27/2021] [Accepted: 12/20/2021] [Indexed: 12/14/2022] Open
Abstract
Nuclear pore complexes (NPCs) discriminate nonspecific macromolecules from importin and exportin receptors, collectively termed “karyopherins” (Kaps), that mediate nucleocytoplasmic transport. This selective barrier function is attributed to the behavior of intrinsically disordered phenylalanine-glycine nucleoporins (FG Nups) that guard the NPC channel. However, NPCs in vivo are typically enriched with different Kaps, and how they impact the NPC barrier remains unknown. Here, we show that two major Kaps, importinβ1/karyopherinβ1 (Kapβ1) and exportin 1/chromosomal maintenance 1 (CRM1), are required to fortify NPC barrier function in vivo. Their enrichment at the NPC is sustained by promiscuous binding interactions with the FG Nups, which enable CRM1 to compensate for the loss of Kapβ1 as a means to maintain NPC barrier function. However, such a compensatory mechanism is constrained by the cellular abundances and different binding kinetics for each respective Kap, as evidenced for importin-5. Consequently, we find that NPC malfunction and nucleocytoplasmic leakage result from poor Kap enrichment.
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Affiliation(s)
- Joanna Kalita
- Biozentrum and the Swiss Nanoscience Institute, University of Basel, Basel, Switzerland
| | - Larisa E Kapinos
- Biozentrum and the Swiss Nanoscience Institute, University of Basel, Basel, Switzerland
| | - Tiantian Zheng
- Department of Physics, University of Toronto, Toronto, Ontario, Canada
| | - Chantal Rencurel
- Biozentrum and the Swiss Nanoscience Institute, University of Basel, Basel, Switzerland
| | - Anton Zilman
- Department of Physics, University of Toronto, Toronto, Ontario, Canada
| | - Roderick Y H Lim
- Biozentrum and the Swiss Nanoscience Institute, University of Basel, Basel, Switzerland
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11
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Belanger KD, Yewdell WT, Barber MF, Russo AN, Pettit MA, Damuth EK, Hussain N, Geier SJ, Belanger KG. Exportin Crm1 is important for Swi6 nuclear shuttling and MBF transcription activation in Saccharomyces cerevisiae. BMC Mol Cell Biol 2022; 23:10. [PMID: 35189816 PMCID: PMC8862259 DOI: 10.1186/s12860-022-00409-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Accepted: 02/07/2022] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Swi6 acts as a transcription factor in budding yeast, functioning in two different heterodimeric complexes, SBF and MBF, that activate the expression of distinct but overlapping sets of genes. Swi6 undergoes regulated changes in nucleocytoplasmic localization throughout the cell cycle that correlate with changes in gene expression. This study investigates how nucleocytoplasmic transport by multiple transport factors may influence specific Swi6 activities. RESULTS Here we show that the exportin Crm1 is important for Swi6 nuclear export and activity. Loss of a putative Crm1 NES or inhibition of Crm1 activity results in changes in nucleocytoplasmic Swi6 localization. Alteration of the Crm1 NES in Swi6 results in decreased MBF-mediated gene expression, but does not affect SBF reporter expression, suggesting that export of Swi6 by Crm1 regulates a subset of Swi6 transcription activation activity. Finally, alteration of the putative Crm1 NES in Swi6 results in cells that are larger than wild type, and this increase in cell size is exacerbated by deletion of Msn5. CONCLUSIONS These data provide evidence that Swi6 has at least two different exportins, Crm1 and Msn5, each of which interacts with a distinct nuclear export signal. We identify a putative nuclear export signal for Crm1 within Swi6, and observe that export by Crm1 or Msn5 independently influences Swi6-regulated expression of a different subset of Swi6-controlled genes. These findings provide new insights into the complex regulation of Swi6 transcription activation activity and the role of nucleocytoplasmic shuttling in regulated gene expression.
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Affiliation(s)
| | - William T. Yewdell
- Department of Biology, Colgate University, Hamilton, NY USA
- Present Address: Immunology Program, Memorial Sloan Kettering Cancer Center, New York, NY USA
| | - Matthew F. Barber
- Department of Biology, Colgate University, Hamilton, NY USA
- Present Address: Department of Biology, University of Oregon, Eugene, OR USA
| | - Amy N. Russo
- Department of Biology, Colgate University, Hamilton, NY USA
- Present Address: The Estée Lauder Companies, Inc., Mellville, NY USA
| | - Mark A. Pettit
- Department of Biology, Colgate University, Hamilton, NY USA
- Present Address: Department of Emergency Medicine, Rochester General Hospital, Rochester, NY USA
| | - Emily K. Damuth
- Department of Biology, Colgate University, Hamilton, NY USA
- Present Address: Department of Emergency Medicine, Cooper University Health Care, Camden, NJ USA
| | - Naveen Hussain
- Department of Biology, Colgate University, Hamilton, NY USA
- Present Address: Kerry’s Place Autism Services, Aurora, ON Canada
| | - Susan J. Geier
- Department of Biology, Colgate University, Hamilton, NY USA
- Present Address: Department of Chemistry, Colgate University, Hamilton, NY USA
| | - Karyn G. Belanger
- Department of Biology, Colgate University, Hamilton, NY USA
- Present Address: Center for Learning, Teaching, and Research, Colgate University, Hamilton, NY USA
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Pasha T, Zatorska A, Sharipov D, Rogelj B, Hortobágyi T, Hirth F. Karyopherin abnormalities in neurodegenerative proteinopathies. Brain 2021; 144:2915-2932. [PMID: 34019093 PMCID: PMC8194669 DOI: 10.1093/brain/awab201] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 04/08/2021] [Accepted: 05/11/2021] [Indexed: 11/12/2022] Open
Abstract
Neurodegenerative proteinopathies are characterized by progressive cell loss that is preceded by the mislocalization and aberrant accumulation of proteins prone to aggregation. Despite their different physiological functions, disease-related proteins like tau, α-synuclein, TAR DNA binding protein-43, fused in sarcoma and mutant huntingtin, all share low complexity regions that can mediate their liquid-liquid phase transitions. The proteins' phase transitions can range from native monomers to soluble oligomers, liquid droplets and further to irreversible, often-mislocalized aggregates that characterize the stages and severity of neurodegenerative diseases. Recent advances into the underlying pathogenic mechanisms have associated mislocalization and aberrant accumulation of disease-related proteins with defective nucleocytoplasmic transport and its mediators called karyopherins. These studies identify karyopherin abnormalities in amyotrophic lateral sclerosis, frontotemporal dementia, Alzheimer's disease, and synucleinopathies including Parkinson's disease and dementia with Lewy bodies, that range from altered expression levels to the subcellular mislocalization and aggregation of karyopherin α and β proteins. The reported findings reveal that in addition to their classical function in nuclear import and export, karyopherins can also act as chaperones by shielding aggregation-prone proteins against misfolding, accumulation and irreversible phase-transition into insoluble aggregates. Karyopherin abnormalities can, therefore, be both the cause and consequence of protein mislocalization and aggregate formation in degenerative proteinopathies. The resulting vicious feedback cycle of karyopherin pathology and proteinopathy identifies karyopherin abnormalities as a common denominator of onset and progression of neurodegenerative disease. Pharmacological targeting of karyopherins, already in clinical trials as therapeutic intervention targeting cancers such as glioblastoma and viral infections like COVID-19, may therefore represent a promising new avenue for disease-modifying treatments in neurodegenerative proteinopathies.
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Affiliation(s)
- Terouz Pasha
- King’s College London, Institute of Psychiatry, Psychology and Neuroscience, Maurice Wohl Clinical Neuroscience Institute, Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, London SE5 9RT, UK
| | - Anna Zatorska
- King’s College London, Institute of Psychiatry, Psychology and Neuroscience, Maurice Wohl Clinical Neuroscience Institute, Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, London SE5 9RT, UK
| | - Daulet Sharipov
- King’s College London, Institute of Psychiatry, Psychology and Neuroscience, Maurice Wohl Clinical Neuroscience Institute, Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, London SE5 9RT, UK
| | - Boris Rogelj
- Jozef Stefan Institute, Department of Biotechnology, 1000 Ljubljana, Slovenia
- University of Ljubljana, Faculty of Chemistry and Chemical Technology, 1000 Ljubljana, Slovenia
| | - Tibor Hortobágyi
- ELKH-DE Cerebrovascular and Neurodegenerative Research Group, Department of Neurology, University of Debrecen, 4032 Debrecen, Hungary
- King's College London, Department of Old Age Psychiatry, Institute of Psychiatry, Psychology and Neuroscience, London SE5 8AF, UK
| | - Frank Hirth
- King’s College London, Institute of Psychiatry, Psychology and Neuroscience, Maurice Wohl Clinical Neuroscience Institute, Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, London SE5 9RT, UK
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13
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Goodman LD, Cope H, Nil Z, Ravenscroft TA, Charng WL, Lu S, Tien AC, Pfundt R, Koolen DA, Haaxma CA, Veenstra-Knol HE, Wassink-Ruiter JSK, Wevers MR, Jones M, Walsh LE, Klee VH, Theunis M, Legius E, Steel D, Barwick KES, Kurian MA, Mohammad SS, Dale RC, Terhal PA, van Binsbergen E, Kirmse B, Robinette B, Cogné B, Isidor B, Grebe TA, Kulch P, Hainline BE, Sapp K, Morava E, Klee EW, Macke EL, Trapane P, Spencer C, Si Y, Begtrup A, Moulton MJ, Dutta D, Kanca O, Wangler MF, Yamamoto S, Bellen HJ, Tan QKG. TNPO2 variants associate with human developmental delays, neurologic deficits, and dysmorphic features and alter TNPO2 activity in Drosophila. Am J Hum Genet 2021; 108:1669-1691. [PMID: 34314705 PMCID: PMC8456166 DOI: 10.1016/j.ajhg.2021.06.019] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Accepted: 06/27/2021] [Indexed: 12/11/2022] Open
Abstract
Transportin-2 (TNPO2) mediates multiple pathways including non-classical nucleocytoplasmic shuttling of >60 cargoes, such as developmental and neuronal proteins. We identified 15 individuals carrying de novo coding variants in TNPO2 who presented with global developmental delay (GDD), dysmorphic features, ophthalmologic abnormalities, and neurological features. To assess the nature of these variants, functional studies were performed in Drosophila. We found that fly dTnpo (orthologous to TNPO2) is expressed in a subset of neurons. dTnpo is critical for neuronal maintenance and function as downregulating dTnpo in mature neurons using RNAi disrupts neuronal activity and survival. Altering the activity and expression of dTnpo using mutant alleles or RNAi causes developmental defects, including eye and wing deformities and lethality. These effects are dosage dependent as more severe phenotypes are associated with stronger dTnpo loss. Interestingly, similar phenotypes are observed with dTnpo upregulation and ectopic expression of TNPO2, showing that loss and gain of Transportin activity causes developmental defects. Further, proband-associated variants can cause more or less severe developmental abnormalities compared to wild-type TNPO2 when ectopically expressed. The impact of the variants tested seems to correlate with their position within the protein. Specifically, those that fall within the RAN binding domain cause more severe toxicity and those in the acidic loop are less toxic. Variants within the cargo binding domain show tissue-dependent effects. In summary, dTnpo is an essential gene in flies during development and in neurons. Further, proband-associated de novo variants within TNPO2 disrupt the function of the encoded protein. Hence, TNPO2 variants are causative for neurodevelopmental abnormalities.
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Affiliation(s)
- Lindsey D Goodman
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Heidi Cope
- Division of Medical Genetics, Department of Pediatrics, Duke University Medical Center, Durham, NC 27710, USA
| | - Zelha Nil
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Thomas A Ravenscroft
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Wu-Lin Charng
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Shenzhao Lu
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - An-Chi Tien
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Rolph Pfundt
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525 GA, PO Box 9101, Nijmegen, the Netherlands
| | - David A Koolen
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525 GA, PO Box 9101, Nijmegen, the Netherlands
| | - Charlotte A Haaxma
- Department of Pediatric Neurology, Amalia Children's Hospital, Radboud University Medical Center, Nijmegen, Geert Grooteplein Zuid 10, 6525 GA, PO Box 9101, the Netherlands
| | - Hermine E Veenstra-Knol
- Department of Genetics, University of Groningen, University Medical Center Groningen, 9713 GZ Groningen, the Netherlands
| | - Jolien S Klein Wassink-Ruiter
- Department of Genetics, University of Groningen, University Medical Center Groningen, 9713 GZ Groningen, the Netherlands
| | - Marijke R Wevers
- Department of Genetics, Radboud University Medical Center, PO Box 9101, 6500 HB Nijmegen, the Netherlands
| | - Melissa Jones
- Houston Area Pediatric Neurology, 24514 Kingsland Blvd, Katy, TX 77494, USA
| | - Laurence E Walsh
- Department of Pediatric Neurology, Riley Hospital for Children, Indianapolis, IN 46202, USA
| | - Victoria H Klee
- Department of Pediatric Neurology, Riley Hospital for Children, Indianapolis, IN 46202, USA
| | - Miel Theunis
- Center for Human Genetics, University Hospital Leuven, Herestraat 49, 3000 Leuven, Belgium
| | - Eric Legius
- Department of Human Genetics, University of Leuven, Herestraat 49, 3000 Leuven, Belgium
| | - Dora Steel
- Molecular Neurosciences, Developmental Neurosciences, UCL Great Ormond Street Institute of Child Health, London WC1N 1EH, UK; Department of Neurology, Great Ormond Street Hospital, London WC1N 3JH, UK
| | - Katy E S Barwick
- Molecular Neurosciences, Developmental Neurosciences, UCL Great Ormond Street Institute of Child Health, London WC1N 1EH, UK
| | - Manju A Kurian
- Molecular Neurosciences, Developmental Neurosciences, UCL Great Ormond Street Institute of Child Health, London WC1N 1EH, UK; Department of Neurology, Great Ormond Street Hospital, London WC1N 3JH, UK
| | - Shekeeb S Mohammad
- T.Y. Nelson Department of Neurology and Neurosurgery, The Children's Hospital at Westmead, Westmead, NSW 2145, Australia; Kids Neuroscience Centre, The Children's Hospital at Westmead, Faculty of Medicine and Health, Sydney Medical School, University of Sydney, Sydney, Westmead, NSW 2145, Australia
| | - Russell C Dale
- T.Y. Nelson Department of Neurology and Neurosurgery, The Children's Hospital at Westmead, Westmead, NSW 2145, Australia; Kids Neuroscience Centre, The Children's Hospital at Westmead, Faculty of Medicine and Health, Sydney Medical School, University of Sydney, Sydney, Westmead, NSW 2145, Australia
| | - Paulien A Terhal
- Department of Genetics, University Medical Center Utrecht, Lundlaan 6, 3584 EA Utrecht, the Netherlands
| | - Ellen van Binsbergen
- Department of Genetics, University Medical Center Utrecht, Lundlaan 6, 3584 EA Utrecht, the Netherlands
| | - Brian Kirmse
- Department of Pediatrics, University of Mississippi Medical Center, Jackson, MS 39216, USA
| | - Bethany Robinette
- Department of Pediatrics, University of Mississippi Medical Center, Jackson, MS 39216, USA
| | - Benjamin Cogné
- Centre hospitalier universitaire (CHU) de Nantes, Service de Génétique Médicale, 9 quai Moncousu, 44093 Nantes, France; INSERM, CNRS, UNIV Nantes, Centre hospitalier universitaire (CHU) de Nantes, l'institut du thorax, 44007 Nantes, France
| | - Bertrand Isidor
- Centre hospitalier universitaire (CHU) de Nantes, Service de Génétique Médicale, 9 quai Moncousu, 44093 Nantes, France; INSERM, CNRS, UNIV Nantes, Centre hospitalier universitaire (CHU) de Nantes, l'institut du thorax, 44007 Nantes, France
| | - Theresa A Grebe
- Phoenix Children's Hospital, Phoenix, AZ 85016, USA; Department of Child Health, University of Arizona College of Medicine Phoenix, Phoenix, AZ 85004, USA
| | - Peggy Kulch
- Phoenix Children's Hospital, Phoenix, AZ 85016, USA
| | - Bryan E Hainline
- Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Katherine Sapp
- Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Eva Morava
- Center for Individualized Medicine, Mayo Clinic, Rochester, MN 55905, USA; Department of Clinical Genomics, Mayo Clinic, Rochester, MN 55905, USA
| | - Eric W Klee
- Center for Individualized Medicine, Mayo Clinic, Rochester, MN 55905, USA; Department of Clinical Genomics, Mayo Clinic, Rochester, MN 55905, USA
| | - Erica L Macke
- Center for Individualized Medicine, Mayo Clinic, Rochester, MN 55905, USA
| | - Pamela Trapane
- University of Florida, College of Medicine, Jacksonville, Jacksonville, FL 32209, USA
| | - Christopher Spencer
- University of Florida, College of Medicine, Jacksonville, Jacksonville, FL 32209, USA
| | - Yue Si
- GeneDx, Gaithersburg, MD 20877, USA
| | | | - Matthew J Moulton
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Debdeep Dutta
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Oguz Kanca
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Michael F Wangler
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Shinya Yamamoto
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA; Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA; Development, Disease Models & Therapeutics Graduate Program, Baylor College of Medicine, Houston, TX 77030, USA
| | - Hugo J Bellen
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA; Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA; Development, Disease Models & Therapeutics Graduate Program, Baylor College of Medicine, Houston, TX 77030, USA; Howard Hughes Medical Institute, Baylor College of Medicine, Houston, TX 77030, USA.
| | - Queenie K-G Tan
- Division of Medical Genetics, Department of Pediatrics, Duke University Medical Center, Durham, NC 27710, USA.
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14
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Kosar F, Akram NA, Ashraf M, Ahmad A, Alyemeni MN, Ahmad P. Impact of exogenously applied trehalose on leaf biochemistry, achene yield and oil composition of sunflower under drought stress. PHYSIOLOGIA PLANTARUM 2021; 172:317-333. [PMID: 32562257 DOI: 10.1111/ppl.13155] [Citation(s) in RCA: 60] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 06/02/2020] [Accepted: 06/17/2020] [Indexed: 05/03/2023]
Abstract
This study was carried out to assess the influence of trehalose, a non-reducing disaccharide involved in improving plant stress tolerance, on two cultivars (Hysun 33 and FH 598) of sunflower (Helianthus annuus L.) grown under control and drought stress conditions. At pre-flowering stage, varying concentrations (10, 20 and 30 mM) of trehalose were applied to the foliage. Drought stress significantly suppressed the plant growth, total soluble proteins, chlorophyll, achene yield per plant, oil percentage, organic contents, as well as oil palmitic and linoleic acids in both sunflower cultivars. External application of trehalose significantly reduced RMP (relative membrane permeability), and the accumulation of H2 O2 (hydrogen peroxide), while a considerable improvement was recorded in shoot fresh and shoot and root dry weights, total soluble proteins, glycinebetaine, AsA (ascorbic acid), total phenolics, achene yield per plant, oil contents, inorganic and organic contents, and the activities of catalase (CAT), superoxide dismutase (SOD) and peroxidase (POD) enzymes under water-limited regimes. The cultivar Hysun 33 was superior to the other cultivar in plant growth, RMP, glycinebetaine, proline, achene yield per plant, oil contents, and palmitic and linoleic acids. Overall, foliar-applied trehalose improved plant growth, oxidative defense system, yield and oil composition of sunflower under drought stress conditions.
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Affiliation(s)
- Firdos Kosar
- Department of Botany, Government College University, Faisalabad, Pakistan
| | - Nudrat Aisha Akram
- Department of Botany, Government College University, Faisalabad, Pakistan
| | | | - Abrar Ahmad
- Department of Botany, Government College University, Faisalabad, Pakistan
| | - Mohammed Nasser Alyemeni
- Botany and Microbiology Department, College of Science, King Saud University, Riyadh, Saudi Arabia
| | - Parvaiz Ahmad
- Botany and Microbiology Department, College of Science, King Saud University, Riyadh, Saudi Arabia
- Department of Botany, S.P. College, Srinagar, Jammu and Kashmir, India
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15
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Modeling the role for nuclear import dynamics in the early embryonic cell cycle. Biophys J 2021; 120:4277-4286. [PMID: 34022240 DOI: 10.1016/j.bpj.2021.05.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 04/22/2021] [Accepted: 05/06/2021] [Indexed: 11/21/2022] Open
Abstract
Nuclear composition determines nuclear function. The early embryos of many species begin life with large pools of maternally provided components that become rapidly imported into an increasing number of nuclei as the cells undergo repeated cleavage divisions. Because early cell cycles are too fast for nuclei to achieve steady-state nucleocytoplasmic partitioning, the composition of cleavage stage nuclei is likely dominated by nuclear import. The end of the rapid cleavage stage and onset of major zygotic transcription, known as the mid-blastula transition (MBT), is controlled by the ratio of nuclei/cytoplasm, indicating that changes in nuclear composition likely mediate MBT timing. Here, we explore how different nuclear import regimes can affect protein accumulation in the nucleus in the early Drosophila embryo. We find that nuclear import differs dramatically for a general nuclear cargo (NLS (nuclear localization signal)-mRFP) and a proposed MBT regulator (histone H3). We show that nuclear import rates of NLS-mRFP in a given nucleus remain relatively unchanged throughout the cleavage cycles, whereas those of H3 halve with each cycle. We model these two distinct modes of nuclear import as "nucleus-limited" and "import-limited" and examine how the two different modes can contribute to different protein accumulation dynamics. Finally, we incorporate these distinct modes of nuclear import into a model for cell-cycle regulation at the MBT and find that the import-limited H3 dynamics contribute to increased robustness and allow for stepwise cell-cycle slowing at the MBT.
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16
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Palacios V, Kimble GC, Tootle TL, Buszczak M. Importin-9 regulates chromosome segregation and packaging in Drosophila germ cells. J Cell Sci 2021; 134:237786. [PMID: 33632744 DOI: 10.1242/jcs.258391] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Accepted: 02/10/2021] [Indexed: 12/29/2022] Open
Abstract
Germ cells undergo distinct nuclear processes as they differentiate into gametes. Although these events must be coordinated to ensure proper maturation, the stage-specific transport of proteins in and out of germ cell nuclei remains incompletely understood. Our efforts to genetically characterize Drosophila genes that exhibit enriched expression in germ cells led to the finding that loss of the highly conserved Importin β/karyopherin family member Importin-9 (Ipo9, herein referring to Ranbp9) results in female and male sterility. Immunofluorescence and fluorescent in situ hybridization revealed that Ipo9KO mutants display chromosome condensation and segregation defects during meiosis. In addition, Ipo9KO mutant males form abnormally structured sperm and fail to properly exchange histones for protamines. Ipo9 physically interacts with proteasome proteins, and Ipo9 mutant males exhibit disruption of the nuclear localization of several proteasome components. Thus, Ipo9 coordinates the nuclear import of functionally related factors necessary for the completion of gametogenesis. This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Victor Palacios
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Garrett C Kimble
- Department of Anatomy and Cell Biology, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - Tina L Tootle
- Department of Anatomy and Cell Biology, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - Michael Buszczak
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.,Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
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17
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Khan AU, Qu R, Ouyang J, Dai J. Role of Nucleoporins and Transport Receptors in Cell Differentiation. Front Physiol 2020; 11:239. [PMID: 32308628 PMCID: PMC7145948 DOI: 10.3389/fphys.2020.00239] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Accepted: 03/02/2020] [Indexed: 12/20/2022] Open
Abstract
Bidirectional molecular movements between the nucleus and cytoplasm take place through nuclear pore complexes (NPCs) embedded in the nuclear membrane. These macromolecular structures are composed of several nucleoporins, which form seven different subcomplexes based on their biochemical affinity. These nucleoporins are integral components of the complex, not only allowing passive transport but also interacting with importin, exportin, and other molecules that are required for transport of protein in various cellular processes. Transport of different proteins is carried out either dependently or independently on transport receptors. As well as facilitating nucleocytoplasmic transport, nucleoporins also play an important role in cell differentiation, possibly by their direct gene interaction. This review will cover the general role of nucleoporins (whether its dependent or independent) and nucleocytoplasmic transport receptors in cell differentiation.
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Affiliation(s)
- Asmat Ullah Khan
- Guangdong Provincial Key Laboratory of Medical Biomechanics, Department of Anatomy, School of Basic Medical Science, Southern Medical University, Guangzhou, China
| | - Rongmei Qu
- Guangdong Provincial Key Laboratory of Medical Biomechanics, Department of Anatomy, School of Basic Medical Science, Southern Medical University, Guangzhou, China
| | - Jun Ouyang
- Guangdong Provincial Key Laboratory of Medical Biomechanics, Department of Anatomy, School of Basic Medical Science, Southern Medical University, Guangzhou, China
| | - Jingxing Dai
- Guangdong Provincial Key Laboratory of Medical Biomechanics, Department of Anatomy, School of Basic Medical Science, Southern Medical University, Guangzhou, China
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18
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Hutten S, Dormann D. Nucleocytoplasmic transport defects in neurodegeneration — Cause or consequence? Semin Cell Dev Biol 2020; 99:151-162. [DOI: 10.1016/j.semcdb.2019.05.020] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Revised: 05/21/2019] [Accepted: 05/21/2019] [Indexed: 12/12/2022]
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19
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Lee JY, Rahman FU, Kim EK, Cho SM, Kim HR, Lee K, Lee CS, Yoon WK, Moon OS, Seo YW, Won YS, Kim HC, Kim BH, Nam KH. Importin-11 is Essential for Normal Embryonic Development in Mice. Int J Med Sci 2020; 17:815-823. [PMID: 32218703 PMCID: PMC7085267 DOI: 10.7150/ijms.40697] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Accepted: 02/18/2020] [Indexed: 11/05/2022] Open
Abstract
Importin-11 (Ipo11) is a novel member of the human importin family of transport receptors (karyopherins), which are known to mediate the nucleocytoplasmic transport of protein and RNA cargos. Despite its role in the transport of protein, we found that knockout of Ipo11 nuclear import factor affects normal embryonic development and govern embryo-lethal phenotypes in mice. In this study, we for the first time produced a mouse line containing null mutation in Ipo11 gene utilized by gene trapping. The Ipo11-/- embryos showed an embryonic lethal phenotype. The Ipo11-/- embryos showed a reduced size at embryonic day 10.5 (E10.5) when compared with Ipo11+/+ or Ipo11+/- embryos and died by E11.5. Whereas Ipo11+/- mice were healthy and fertile, and there was no detectable changes in embryonic lethality and phenotype when reviewed. In the X-gal staining with the Ipo11-/- or Ipo11+/- embryos, strong X-gal staining positivity was detected systematically in the whole mount embryos at E10.5, although almost no X-gal positivity was detected at E9.5, indicating that the embryos die soon after the process of Ipo11 expression started. These results indicate that Ipo11 is essential for the normal embryonic development in mice.
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Affiliation(s)
- Ju-Young Lee
- Laboratory Animal Resource Center, Korea Research Institute of Bioscience and Biotechnology, Yeonjudanji-ro 30, Chungbuk 28116, Korea.,Department of Public Health, College of Natural Science, Keimyung University, Daegu, 42601, Korea
| | - Faiz Ur Rahman
- Laboratory Animal Resource Center, Korea Research Institute of Bioscience and Biotechnology, Yeonjudanji-ro 30, Chungbuk 28116, Korea
| | - Eun-Kyeung Kim
- Laboratory Animal Resource Center, Korea Research Institute of Bioscience and Biotechnology, Yeonjudanji-ro 30, Chungbuk 28116, Korea
| | - Sang-Mi Cho
- Laboratory Animal Resource Center, Korea Research Institute of Bioscience and Biotechnology, Yeonjudanji-ro 30, Chungbuk 28116, Korea
| | - Hae-Rim Kim
- Laboratory Animal Resource Center, Korea Research Institute of Bioscience and Biotechnology, Yeonjudanji-ro 30, Chungbuk 28116, Korea
| | - Kihoon Lee
- Laboratory Animal Resource Center, Korea Research Institute of Bioscience and Biotechnology, Yeonjudanji-ro 30, Chungbuk 28116, Korea
| | - Chin-Soo Lee
- Laboratory Animal Resource Center, Korea Research Institute of Bioscience and Biotechnology, Yeonjudanji-ro 30, Chungbuk 28116, Korea
| | - Won-Kee Yoon
- Laboratory Animal Resource Center, Korea Research Institute of Bioscience and Biotechnology, Yeonjudanji-ro 30, Chungbuk 28116, Korea
| | - Ok-Sung Moon
- Laboratory Animal Resource Center, Korea Research Institute of Bioscience and Biotechnology, Yeonjudanji-ro 30, Chungbuk 28116, Korea
| | - Young-Won Seo
- Laboratory Animal Resource Center, Korea Research Institute of Bioscience and Biotechnology, Yeonjudanji-ro 30, Chungbuk 28116, Korea
| | - Young-Suk Won
- Laboratory Animal Resource Center, Korea Research Institute of Bioscience and Biotechnology, Yeonjudanji-ro 30, Chungbuk 28116, Korea
| | - Hyoung-Chin Kim
- Laboratory Animal Resource Center, Korea Research Institute of Bioscience and Biotechnology, Yeonjudanji-ro 30, Chungbuk 28116, Korea
| | - Bae-Hwan Kim
- Department of Public Health, College of Natural Science, Keimyung University, Daegu, 42601, Korea
| | - Ki-Hoan Nam
- Laboratory Animal Resource Center, Korea Research Institute of Bioscience and Biotechnology, Yeonjudanji-ro 30, Chungbuk 28116, Korea
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20
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Choi JY, Shin D, Lee HJ, Oh JD. Comparison of long noncoding RNA between muscles and adipose tissues in Hanwoo beef cattle. Anim Cells Syst (Seoul) 2019; 23:50-58. [PMID: 30834159 PMCID: PMC6394308 DOI: 10.1080/19768354.2018.1512522] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 08/01/2018] [Accepted: 08/03/2018] [Indexed: 02/07/2023] Open
Abstract
Long noncoding RNAs (lncRNAs) regulate the expression of mRNA and can affect various biological processes and phenotypes. Currently, studies of lncRNAs in cattle are under way, but their exact function for several tissues has not yet been established. Hanwoo cattle (Bos taurus coreanae) have inhabited the Korean peninsula for about 6000 years and are one of the representative domesticated animals in Korea. As a result of intensive breeding, the meat of Hanwoo cattle is high in marbling content and is preferred by Koreans and other East Asian people. In this study, the expression of lncRNAs was identified in 36 samples from skeletal muscle and three adipose tissues (intramuscular, subcutaneous, and omental) of nine Hanwoo individuals. We identified 76 tissue-specific lncRNAs for each of the four tissues using the differences in expression levels. Through QTL information, we could identify 12 lncRNAs associated with shear force and six lncRNAs associated with body weight, which are two important traits in the Hanwoo population breeding strategy. By the physical position comparison of lncRNA and Bovine transcripts information, we could identify 11 lncRNAs that were in bovine transcripts, and four of the 11 genes related to transcripts of lncRNAs were biologically associated with muscle function. We believe this Hanwoo lncRNAs study will help reveal the lncRNA role in the physiological mechanisms of these four tissues.
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Affiliation(s)
- Jae-Young Choi
- The Animal Molecular Genetics and Breeding Center, Chonbuk National University, Jeonju, Republic of Korea
| | - Donghyun Shin
- Department of Animal Biotechnology, College of Agricultural and Life Sciences, Chonbuk National University, Jeonju, Republic of Korea
| | - Hyun-Jeong Lee
- Animal Nutritional & Physiology Team, National Institute of Animal Science, Wanju, Republic of Korea
| | - Jae-Don Oh
- Department of Animal Biotechnology, College of Agricultural and Life Sciences, Chonbuk National University, Jeonju, Republic of Korea
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21
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Kosyna FK, Depping R. Controlling the Gatekeeper: Therapeutic Targeting of Nuclear Transport. Cells 2018; 7:cells7110221. [PMID: 30469340 PMCID: PMC6262578 DOI: 10.3390/cells7110221] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Revised: 11/16/2018] [Accepted: 11/17/2018] [Indexed: 12/11/2022] Open
Abstract
Nuclear transport receptors of the karyopherin superfamily of proteins transport macromolecules from one compartment to the other and are critical for both cell physiology and pathophysiology. The nuclear transport machinery is tightly regulated and essential to a number of key cellular processes since the spatiotemporally expression of many proteins and the nuclear transporters themselves is crucial for cellular activities. Dysregulation of the nuclear transport machinery results in localization shifts of specific cargo proteins and associates with the pathogenesis of disease states such as cancer, inflammation, viral illness and neurodegenerative diseases. Therefore, inhibition of the nuclear transport system has future potential for therapeutic intervention and could contribute to the elucidation of disease mechanisms. In this review, we recapitulate clue findings in the pathophysiological significance of nuclear transport processes and describe the development of nuclear transport inhibitors. Finally, clinical implications and results of the first clinical trials are discussed for the most promising nuclear transport inhibitors.
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Affiliation(s)
- Friederike K Kosyna
- Institute of Physiology, Center for Structural and Cell Biology in Medicine, University of Lübeck, Ratzeburger Allee 160, D-23562 Lübeck, Germany.
| | - Reinhard Depping
- Institute of Physiology, Center for Structural and Cell Biology in Medicine, University of Lübeck, Ratzeburger Allee 160, D-23562 Lübeck, Germany.
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22
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Duan Z, Xu H, Ji X, Zhao J, Xu H, Hu Y, Deng S, Hu S, Liu X. Importin α5 negatively regulates importin β1-mediated nuclear import of Newcastle disease virus matrix protein and viral replication and pathogenicity in chicken fibroblasts. Virulence 2018. [PMID: 29532715 PMCID: PMC5955436 DOI: 10.1080/21505594.2018.1449507] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The matrix (M) protein of Newcastle disease virus (NDV) is demonstrated to localize in the nucleus via intrinsic nuclear localization signal (NLS), but cellular proteins involved in the nuclear import of NDV M protein and the role of M's nuclear localization in the replication and pathogenicity of NDV remain unclear. In this study, importin β1 was screened to interact with NDV M protein by yeast two-hybrid screening. This interaction was subsequently confirmed by co-immunoprecipitation and pull-down assays. In vitro binding studies indicated that the NLS region of M protein and the amino acids 336–433 of importin β1 that belonged to the RanGTP binding region were important for binding. Importantly, a recombinant virus with M/NLS mutation resulted in a pathotype change of NDV and attenuated viral replication and pathogenicity in chicken fibroblasts and SPF chickens. In agreement with the binding data, nuclear import of NDV M protein in digitonin-permeabilized HeLa cells required both importin β1 and RanGTP. Interestingly, importin α5 was verified to interact with M protein through binding importin β1. However, importin β1 or importin α5 depletion by siRNA resulted in different results, which showed the obviously cytoplasmic or nuclear accumulation of M protein and the remarkably decreased or increased replication ability and pathogenicity of NDV in chicken fibroblasts, respectively. Our findings therefore demonstrate for the first time the nuclear import mechanism of NDV M protein and the negative regulation role of importin α5 in importin β1-mediated nuclear import of M protein and the replication and pathogenicity of a paramyxovirus.
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Affiliation(s)
- Zhiqiang Duan
- a Key Laboratory of Animal Genetics, Breeding and Reproduction in The Plateau Mountainous Region, Ministry of Education , Guizhou University , Guiyang , China.,b College of Animal Science , Guizhou University , Guiyang , China
| | - Haixu Xu
- c Key Laboratory of Animal Infectious Diseases of Ministry of Agriculture , Yangzhou University , Yangzhou , China
| | - Xinqin Ji
- a Key Laboratory of Animal Genetics, Breeding and Reproduction in The Plateau Mountainous Region, Ministry of Education , Guizhou University , Guiyang , China.,b College of Animal Science , Guizhou University , Guiyang , China
| | - Jiafu Zhao
- a Key Laboratory of Animal Genetics, Breeding and Reproduction in The Plateau Mountainous Region, Ministry of Education , Guizhou University , Guiyang , China.,b College of Animal Science , Guizhou University , Guiyang , China
| | - Houqiang Xu
- a Key Laboratory of Animal Genetics, Breeding and Reproduction in The Plateau Mountainous Region, Ministry of Education , Guizhou University , Guiyang , China.,b College of Animal Science , Guizhou University , Guiyang , China
| | - Yan Hu
- b College of Animal Science , Guizhou University , Guiyang , China
| | - Shanshan Deng
- b College of Animal Science , Guizhou University , Guiyang , China
| | - Shunlin Hu
- c Key Laboratory of Animal Infectious Diseases of Ministry of Agriculture , Yangzhou University , Yangzhou , China
| | - Xiufan Liu
- c Key Laboratory of Animal Infectious Diseases of Ministry of Agriculture , Yangzhou University , Yangzhou , China
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23
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Nganou G, Silva CG, Gladwyn-Ng I, Engel D, Coumans B, Delgado-Escueta AV, Tanaka M, Nguyen L, Grisar T, de Nijs L, Lakaye B. Importin-8 Modulates Division of Apical Progenitors, Dendritogenesis and Tangential Migration During Development of Mouse Cortex. Front Mol Neurosci 2018; 11:234. [PMID: 30042658 PMCID: PMC6048241 DOI: 10.3389/fnmol.2018.00234] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Accepted: 06/13/2018] [Indexed: 01/18/2023] Open
Abstract
The building of the brain is a multistep process that requires the coordinate expression of thousands of genes and an intense nucleocytoplasmic transport of RNA and proteins. This transport is mediated by karyopherins that comprise importins and exportins. Here, we investigated the role of the ß-importin, importin-8 (IPO8) during mouse cerebral corticogenesis as several of its cargoes have been shown to be essential during this process. First, we showed that Ipo8 mRNA is expressed in mouse brain at various embryonic ages with a clear signal in the sub-ventricular/ventricular zone (SVZ/VZ), the cerebral cortical plate (CP) and the ganglionic eminences. We found that acute knockdown of IPO8 in cortical progenitors reduced both their proliferation and cell cycle exit leading to the increase in apical progenitor pool without influencing the number of basal progenitors (BPs). Projection neurons ultimately reached their appropriate cerebral cortical layer, but their dendritogenesis was specifically affected, resulting in neurons with reduced dendrite complexity. IPO8 knockdown also slowed the migration of cortical interneurons. Together, our data demonstrate that IPO8 contribute to the coordination of several critical steps of cerebral cortex development. These results suggest that the impairment of IPO8 function might be associated with some diseases of neuronal migration defects.
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Affiliation(s)
- Gerry Nganou
- GIGA-Neurosciences, University of Liege, Liege, Belgium.,GENESS International Consortium, Los Angeles, CA, United States
| | - Carla G Silva
- GIGA-Neurosciences, University of Liege, Liege, Belgium
| | | | | | - Bernard Coumans
- GIGA-Neurosciences, University of Liege, Liege, Belgium.,GENESS International Consortium, Los Angeles, CA, United States
| | - Antonio V Delgado-Escueta
- GENESS International Consortium, Los Angeles, CA, United States.,Epilepsy Genetics/Genomics Lab, Neurology and Research Services, VA Greater Los Angeles Healthcare System (VA GLAHS), University of California, Los Angeles, Los Angeles, CA, United States
| | - Miyabi Tanaka
- GENESS International Consortium, Los Angeles, CA, United States.,Epilepsy Genetics/Genomics Lab, Neurology and Research Services, VA Greater Los Angeles Healthcare System (VA GLAHS), University of California, Los Angeles, Los Angeles, CA, United States
| | | | - Thierry Grisar
- GIGA-Neurosciences, University of Liege, Liege, Belgium.,GENESS International Consortium, Los Angeles, CA, United States
| | - Laurence de Nijs
- GENESS International Consortium, Los Angeles, CA, United States.,MHeNS, Maastricht University, Maastricht, Netherlands
| | - Bernard Lakaye
- GIGA-Neurosciences, University of Liege, Liege, Belgium.,GENESS International Consortium, Los Angeles, CA, United States
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24
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Beck M, Schirmacher P, Singer S. Alterations of the nuclear transport system in hepatocellular carcinoma - New basis for therapeutic strategies. J Hepatol 2017; 67:1051-1061. [PMID: 28673770 DOI: 10.1016/j.jhep.2017.06.021] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Revised: 06/20/2017] [Accepted: 06/21/2017] [Indexed: 12/20/2022]
Abstract
Hepatocellular carcinoma (HCC) is among the most prevalent human malignancies worldwide with rising incidence in industrialised countries, few therapeutic options and poor prognosis. To expand and improve therapeutic strategies, identification of drug targets involved in several liver cancer-related pathways is crucial. Virtually all signal transduction cascades cross the nuclear envelope and therefore require components of the nuclear transport system (NTS), including nuclear transport receptors (e.g. importins and exportins) and the nuclear pore complex. Accordingly, members of the NTS represent promising targets for therapeutic intervention. Selective inhibitors of nuclear export have already entered clinical trials for various malignancies. Herein, we review the current knowledge regarding alterations of the NTS and their potential for targeted therapy in HCC.
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Affiliation(s)
- Martin Beck
- European Molecular Biology Laboratory, Heidelberg, Germany
| | | | - Stephan Singer
- European Molecular Biology Laboratory, Heidelberg, Germany; Institute of Pathology, University Hospital Heidelberg, Germany.
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25
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Duan Z, Zhao J, Xu H, Xu H, Ji X, Chen X, Xiong J. Characterization of the nuclear import pathway for BLM protein. Arch Biochem Biophys 2017; 634:57-68. [PMID: 29017749 DOI: 10.1016/j.abb.2017.09.019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2017] [Revised: 09/18/2017] [Accepted: 09/29/2017] [Indexed: 01/13/2023]
Abstract
Numerous studies have shown that nuclear localization of BLM protein, a member of the RecQ helicases, mediated by nuclear localization signal (NLS) is critical for DNA recombination, replication and transcription, but the mechanism by which BLM protein is imported into the nucleus remains unknown. In this study, the nuclear import pathway for BLM was investigated. We found that nuclear import of BLM was inhibited by two dominant-negative mutants of importin β1 and NTF2/E42K, which lacks the ability to bind Ran and RanGDP, respectively, but was not inhibited by the Ran/Q69L, which is deficient in GTP hydrolysis. Further studies revealed that nuclear import of BLM was reconstituted using importin β1, RanGDP and NTF2 in digitonin-permeabilized HeLa cells. Moreover, BLM had direct binding to importin β1 through its NLS domain with the 14-16 HEAT repeats of importin β1. Furthermore, importin β1, Ran or NTF2 depletion by siRNA disrupted the accumulation of BLM protein in the nucleus. These results showed that BLM enters the nucleus via the importin β1, RanGDP and NTF2 dependent pathway, demonstrating for the first time the nuclear trafficking mechanism of a DNA helicase.
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Affiliation(s)
- Zhiqiang Duan
- Key Laboratory of Animal Genetics, Breeding and Reproduction in the Plateau Mountainous Region, Ministry of Education, Guizhou University, Guiyang 550025, China; College of Animal Science, Guizhou University, Guiyang 550025, China
| | - Jiafu Zhao
- Key Laboratory of Animal Genetics, Breeding and Reproduction in the Plateau Mountainous Region, Ministry of Education, Guizhou University, Guiyang 550025, China; College of Animal Science, Guizhou University, Guiyang 550025, China
| | - Houqiang Xu
- Key Laboratory of Animal Genetics, Breeding and Reproduction in the Plateau Mountainous Region, Ministry of Education, Guizhou University, Guiyang 550025, China; College of Animal Science, Guizhou University, Guiyang 550025, China.
| | - Haixu Xu
- College of Veterinary Medicine, Yangzhou University, Yangzhou 225009, China
| | - Xinqin Ji
- College of Animal Science, Guizhou University, Guiyang 550025, China
| | - Xiang Chen
- Key Laboratory of Animal Genetics, Breeding and Reproduction in the Plateau Mountainous Region, Ministry of Education, Guizhou University, Guiyang 550025, China; College of Animal Science, Guizhou University, Guiyang 550025, China
| | - Jianming Xiong
- College of Animal Science, Guizhou University, Guiyang 550025, China
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26
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Competitive regulation of IPO4 transcription by ELK1 and GABP. Gene 2017; 613:30-38. [DOI: 10.1016/j.gene.2017.02.030] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Revised: 01/25/2017] [Accepted: 02/24/2017] [Indexed: 11/19/2022]
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27
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Kimura M, Morinaka Y, Imai K, Kose S, Horton P, Imamoto N. Extensive cargo identification reveals distinct biological roles of the 12 importin pathways. eLife 2017; 6:e21184. [PMID: 28117667 PMCID: PMC5305215 DOI: 10.7554/elife.21184] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Accepted: 01/17/2017] [Indexed: 12/31/2022] Open
Abstract
Vast numbers of proteins are transported into and out of the nuclei by approximately 20 species of importin-β family nucleocytoplasmic transport receptors. However, the significance of the multiple parallel transport pathways that the receptors constitute is poorly understood because only limited numbers of cargo proteins have been reported. Here, we identified cargo proteins specific to the 12 species of human import receptors with a high-throughput method that employs stable isotope labeling with amino acids in cell culture, an in vitro reconstituted transport system, and quantitative mass spectrometry. The identified cargoes illuminated the manner of cargo allocation to the receptors. The redundancies of the receptors vary widely depending on the cargo protein. Cargoes of the same receptor are functionally related to one another, and the predominant protein groups in the cargo cohorts differ among the receptors. Thus, the receptors are linked to distinct biological processes by the nature of their cargoes.
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Affiliation(s)
| | | | - Kenichiro Imai
- Artificial Intelligence Research Center, National Institute of Advanced Industrial Science and Technology, Tokyo, Japan
- Biotechnology Research Institute for Drug Discovery, National Institute of Advanced Industrial Science and Technology, Tokyo, Japan
| | - Shingo Kose
- Cellular Dynamics Laboratory, RIKEN, Wako, Japan
| | - Paul Horton
- Artificial Intelligence Research Center, National Institute of Advanced Industrial Science and Technology, Tokyo, Japan
- Biotechnology Research Institute for Drug Discovery, National Institute of Advanced Industrial Science and Technology, Tokyo, Japan
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28
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Microarray Analysis of Gene Expression in Saccharomyces cerevisiae kap108Δ Mutants upon Addition of Oxidative Stress. G3-GENES GENOMES GENETICS 2016; 6:1131-9. [PMID: 26888869 PMCID: PMC4825647 DOI: 10.1534/g3.116.027011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Protein transport between the nucleus and cytoplasm of eukaryotic cells is tightly regulated, providing a mechanism for controlling intracellular localization of proteins, and regulating gene expression. In this study, we have investigated the importance of nucleocytoplasmic transport mediated by the karyopherin Kap108 in regulating cellular responses to oxidative stress in Saccharomyces cerevisiae. We carried out microarray analyses on wild-type and kap108 mutant cells grown under normal conditions, shortly after introduction of oxidative stress, after 1 hr of oxidative stress, and 1 hr after oxidative stress was removed. We observe more than 500 genes that undergo a 40% or greater change in differential expression between wild-type and kap108Δ cells under at least one of these conditions. Genes undergoing changes in expression can be categorized in two general groups: 1) those that are differentially expressed between wild-type and kap108Δ cells, no matter the oxidative stress conditions; and 2) those that have patterns of response dependent upon both the absence of Kap108, and introduction or removal of oxidative stress. Gene ontology analysis reveals that, among the genes whose expression is reduced in the absence of Kap108 are those involved in stress response and intracellular transport, while those overexpressed are largely involved in mating and pheromone response. We also identified 25 clusters of genes that undergo similar patterns of change in gene expression when oxidative stresses are added and subsequently removed, including genes involved in stress response, oxidation–reduction processing, iron homeostasis, ascospore wall assembly, transmembrane transport, and cell fusion during mating. These data suggest that Kap108 is important for regulating expression of genes involved in a variety of specific cell functions.
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29
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Stelma T, Chi A, van der Watt PJ, Verrico A, Lavia P, Leaner VD. Targeting nuclear transporters in cancer: Diagnostic, prognostic and therapeutic potential. IUBMB Life 2016; 68:268-80. [PMID: 26970212 DOI: 10.1002/iub.1484] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Accepted: 01/20/2016] [Indexed: 01/10/2023]
Abstract
The Karyopherin superfamily is a major class of soluble transport receptors consisting of both import and export proteins. The trafficking of proteins involved in transcription, cell signalling and cell cycle regulation among other functions across the nuclear membrane is essential for normal cellular functioning. However, in cancer cells, the altered expression or localization of nuclear transporters as well as the disruption of endogenous nuclear transport inhibitors are some ways in which the Karyopherin proteins are dysregulated. The value of nuclear transporters in the diagnosis, prognosis and treatment of cancer is currently being elucidated with recent studies highlighting their potential as biomarkers and therapeutic targets.
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Affiliation(s)
- Tamara Stelma
- Division of Medical Biochemistry, Department of Integrative Biomedical Sciences, SAMRC/UCT Gynaecological Cancer Research Centre, Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Alicia Chi
- Division of Medical Biochemistry, Department of Integrative Biomedical Sciences, SAMRC/UCT Gynaecological Cancer Research Centre, Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Pauline J van der Watt
- Division of Medical Biochemistry, Department of Integrative Biomedical Sciences, SAMRC/UCT Gynaecological Cancer Research Centre, Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Annalisa Verrico
- Institute of Molecular Biology and Pathology, National Research Council of Italy, C/O University of Roma "La Sapienza", Rome, Italy
| | - Patrizia Lavia
- Institute of Molecular Biology and Pathology, National Research Council of Italy, C/O University of Roma "La Sapienza", Rome, Italy
| | - Virna D Leaner
- Division of Medical Biochemistry, Department of Integrative Biomedical Sciences, SAMRC/UCT Gynaecological Cancer Research Centre, Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
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30
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Importin-7 mediates memory consolidation through regulation of nuclear translocation of training-activated MAPK in Drosophila. Proc Natl Acad Sci U S A 2016; 113:3072-7. [PMID: 26929354 DOI: 10.1073/pnas.1520401113] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Translocation of signaling molecules, MAPK in particular, from the cytosol to nucleus represents a universal key element in initiating the gene program that determines memory consolidation. Translocation mechanisms and their behavioral impact, however, remain to be determined. Here, we report that a highly conserved nuclear transporter, Drosophila importin-7 (DIM-7), regulates import of training-activated MAPK for consolidation of long-term memory (LTM). We show that silencing DIM-7 functions results in impaired LTM, whereas overexpression of DIM-7 enhances LTM. This DIM-7-dependent regulation of LTM is confined to a consolidation time window and in mushroom body neurons. Image data show that bidirectional alteration in DIM-7 expression results in proportional changes in the intensity of training-activated MAPK accumulated within the nuclei of mushroom body neurons during LTM consolidation. Such DIM-7-regulated nuclear accumulation of activated MAPK is observed only in the training specified for LTM induction and determines the amplitude, but not the time course, of memory consolidation.
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31
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Chen JWC, Barker AR, Wakefield JG. The Ran Pathway in Drosophila melanogaster Mitosis. Front Cell Dev Biol 2015; 3:74. [PMID: 26636083 PMCID: PMC4659922 DOI: 10.3389/fcell.2015.00074] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Accepted: 11/09/2015] [Indexed: 11/29/2022] Open
Abstract
Over the last two decades, the small GTPase Ran has emerged as a central regulator of both mitosis and meiosis, particularly in the generation, maintenance, and regulation of the microtubule (MT)-based bipolar spindle. Ran-regulated pathways in mitosis bear many similarities to the well-characterized functions of Ran in nuclear transport and, as with transport, the majority of these mitotic effects are mediated through affecting the physical interaction between karyopherins and Spindle Assembly Factors (SAFs)—a loose term describing proteins or protein complexes involved in spindle assembly through promoting nucleation, stabilization, and/or depolymerization of MTs, through anchoring MTs to specific structures such as centrosomes, chromatin or kinetochores, or through sliding MTs along each other to generate the force required to achieve bipolarity. As such, the Ran-mediated pathway represents a crucial functional module within the wider spindle assembly landscape. Research into mitosis using the model organism Drosophila melanogaster has contributed substantially to our understanding of centrosome and spindle function. However, in comparison to mammalian systems, very little is known about the contribution of Ran-mediated pathways in Drosophila mitosis. This article sets out to summarize our understanding of the roles of the Ran pathway components in Drosophila mitosis, focusing on the syncytial blastoderm embryo, arguing that it can provide important insights into the conserved functions on Ran during spindle formation.
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Affiliation(s)
- Jack W C Chen
- Biosciences, College of Life and Environmental Sciences, University of Exeter Exeter, UK
| | - Amy R Barker
- Biosciences, College of Life and Environmental Sciences, University of Exeter Exeter, UK ; Centre for Microvascular Research, William Harvey Research Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London London, UK
| | - James G Wakefield
- Biosciences, College of Life and Environmental Sciences, University of Exeter Exeter, UK
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32
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Christie M, Chang CW, Róna G, Smith KM, Stewart AG, Takeda AAS, Fontes MRM, Stewart M, Vértessy BG, Forwood JK, Kobe B. Structural Biology and Regulation of Protein Import into the Nucleus. J Mol Biol 2015; 428:2060-90. [PMID: 26523678 DOI: 10.1016/j.jmb.2015.10.023] [Citation(s) in RCA: 176] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Revised: 10/16/2015] [Accepted: 10/24/2015] [Indexed: 11/28/2022]
Abstract
Proteins are translated in the cytoplasm, but many need to access the nucleus to perform their functions. Understanding how these nuclear proteins are transported through the nuclear envelope and how the import processes are regulated is therefore an important aspect of understanding cell function. Structural biology has played a key role in understanding the molecular events during the transport processes and their regulation, including the recognition of nuclear targeting signals by the corresponding receptors. Here, we review the structural basis of the principal nuclear import pathways and the molecular basis of their regulation. The pathways involve transport factors that are members of the β-karyopherin family, which can bind cargo directly (e.g., importin-β, transportin-1, transportin-3, importin-13) or through adaptor proteins (e.g., importin-α, snurportin-1, symportin-1), as well as unrelated transport factors such as Hikeshi, involved in the transport of heat-shock proteins, and NTF2, involved in the transport of RanGDP. Solenoid proteins feature prominently in these pathways. Nuclear transport factors recognize nuclear targeting signals on the cargo proteins, including the classical nuclear localization signals, recognized by the adaptor importin-α, and the PY nuclear localization signals, recognized by transportin-1. Post-translational modifications, particularly phosphorylation, constitute key regulatory mechanisms operating in these pathways.
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Affiliation(s)
- Mary Christie
- The Garvan Institute of Medical Research, 384 Victoria Street, Darlinghurst, NSW 2010, Australia; St Vincent's Clinical School, University of New South Wales Faculty of Medicine, Darlinghurst, NSW 2010, Australia
| | - Chiung-Wen Chang
- School of Chemistry and Molecular Biosciences, Institute for Molecular Bioscience and Australian Infectious Diseases Research Centre, University of Queensland, Brisbane, QLD 4072, Australia; Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Gergely Róna
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest H-1117, Hungary; Department of Applied Biotechnology and Food Sciences, Budapest University of Technology and Economics, Budapest H-1111, Hungary
| | - Kate M Smith
- School of Biomedical Sciences, Charles Sturt University, Wagga Wagga, NSW 2650, Australia
| | - Alastair G Stewart
- School of Molecular Bioscience, The University of Sydney, Sydney, NSW 2006, Australia
| | - Agnes A S Takeda
- Department of Physics and Biophysics, Institute of Biosciences, Universidade Estadual Paulista, Botucatu, São Paulo 18618-000, Brazil
| | - Marcos R M Fontes
- Department of Physics and Biophysics, Institute of Biosciences, Universidade Estadual Paulista, Botucatu, São Paulo 18618-000, Brazil
| | - Murray Stewart
- School of Chemistry and Molecular Biosciences, Institute for Molecular Bioscience and Australian Infectious Diseases Research Centre, University of Queensland, Brisbane, QLD 4072, Australia; MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, United Kingdom
| | - Beáta G Vértessy
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest H-1117, Hungary; Department of Applied Biotechnology and Food Sciences, Budapest University of Technology and Economics, Budapest H-1111, Hungary
| | - Jade K Forwood
- School of Biomedical Sciences, Charles Sturt University, Wagga Wagga, NSW 2650, Australia
| | - Bostjan Kobe
- School of Chemistry and Molecular Biosciences, Institute for Molecular Bioscience and Australian Infectious Diseases Research Centre, University of Queensland, Brisbane, QLD 4072, Australia.
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33
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Abstract
The Karyopherin-β family of proteins mediates nuclear transport of macromolecules. Nuclear versus cytoplasmic localization of proteins is often suggested by the presence of NLSs (nuclear localization signals) or NESs (nuclear export signals). Import-Karyopherin-βs or Importins bind to NLSs in their protein cargos to transport them through nuclear pore complexes into the nucleus. Until recently, only two classes of NLS had been biochemically and structurally characterized: the classical NLS, which is recognized by the Importin-α/β heterodimer and the PY-NLS (proline-tyrosine NLS), which is recognized by Karyopherin-β2 or Transportin-1. Structures of two other Karyopherin-βs, Kap121 and Transportin-SR2, in complex with their respective cargos were reported for the first time recently, revealing two new distinct classes of NLSs. The present paper briefly describes the classical NLS, reviews recent literature on the PY-NLS and provides in-depth reviews of the two newly discovered classes of NLSs that bind Kap121p and Transportin-SR respectively.
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34
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Bauer NC, Doetsch PW, Corbett AH. Mechanisms Regulating Protein Localization. Traffic 2015; 16:1039-61. [PMID: 26172624 DOI: 10.1111/tra.12310] [Citation(s) in RCA: 105] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2015] [Revised: 07/08/2015] [Accepted: 07/08/2015] [Indexed: 12/23/2022]
Abstract
Cellular functions are dictated by protein content and activity. There are numerous strategies to regulate proteins varying from modulating gene expression to post-translational modifications. One commonly used mode of regulation in eukaryotes is targeted localization. By specifically redirecting the localization of a pool of existing protein, cells can achieve rapid changes in local protein function. Eukaryotic cells have evolved elegant targeting pathways to direct proteins to the appropriate cellular location or locations. Here, we provide a general overview of these localization pathways, with a focus on nuclear and mitochondrial transport, and present a survey of the evolutionarily conserved regulatory strategies identified thus far. We end with a description of several specific examples of proteins that exploit localization as an important mode of regulation.
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Affiliation(s)
- Nicholas C Bauer
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA.,Graduate Program in Biochemistry, Cell, and Developmental Biology, Emory University School of Medicine, Atlanta, GA 30322, USA.,Current address: Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
| | - Paul W Doetsch
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA.,Winship Cancer Institute, Emory University School of Medicine, Atlanta, GA 30322, USA.,Department of Radiation Oncology, Emory University School of Medicine, Atlanta, GA 30322, USA.,Department of Hematology and Medical Oncology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Anita H Corbett
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA.,Winship Cancer Institute, Emory University School of Medicine, Atlanta, GA 30322, USA
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Upregulation of KPNβ1 in gastric cancer cell promotes tumor cell proliferation and predicts poor prognosis. Tumour Biol 2015; 37:661-72. [PMID: 26242264 DOI: 10.1007/s13277-015-3839-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Accepted: 07/24/2015] [Indexed: 12/14/2022] Open
Abstract
KPNβ1, also known as importin β, P97, is reported as one of soluble transport factors that mediates transportion of proteins and RNAs between the nucleus and cytoplasm in cellular process. Recent studies show that KPNβ1 is a tumor gene which is highly expressed in several malignant tumors such as ovarian cancer, cervical tumor, neck cancer, and lung cancer via promoting cell proliferation or inhibiting cell apoptotic pathways. However, the the role of KPNβ1 in gastric cancer remains unclear. In this study, Western blot and immunohistochemistrical analyses showed that KPNβ1 was significantly upregulated in clinical gastric cancer specimens compared with adjacent noncancerous tissues. KPNβ1 was positively correlated with tumor grade, Ki-67, and predicted poor prognosis of gastric cancer. More importantly, through starvation-refeeding model, CCK8 assay, flow cytometry, colony formation assays, the vitro studies demonstrated that KPNβ1 promoted proliferation of gastric cancer cells, while KPNβ1 knockdown led to decreased cell proliferation and arrested cell cycle at G1 phase. Furthermore, our results also indicated that KPNβ1 expression could result in docetaxel resistance. And, KPNβ1 could interact with Stat1, contributed to its nucleus import in gastric cancer cells. These findings provided a novel promising therapeutic targets for clinical treatment against human gastric cancer.
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Hyper-dependence of breast cancer cell types on the nuclear transporter Importin β1. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1853:1870-8. [PMID: 25960398 DOI: 10.1016/j.bbamcr.2015.05.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Revised: 04/28/2015] [Accepted: 05/03/2015] [Indexed: 12/27/2022]
Abstract
We previously reported that overexpression of members of the Importin (Imp) superfamily of nuclear transporters results in increased nuclear trafficking through conventional transport pathways in tumour cells. Here we show for the first time that the extent of overexpression of Impβ1 correlates with disease state in the MCF10 human breast tumour progression system. Excitingly, we find that targeting Impβ1 activity through siRNA is >30 times more efficient in decreasing the viability of malignant ductal carcinoma cells compared to isogenic non-transformed counterparts, and is highly potent and tumour selective at subnanomolar concentrations. Tumour cell selectivity of the siRNA effects was unique to Impβ1 and not other Imps, with flow cytometric analysis showing >60% increased cell death compared to controls concomitant with reduced nuclear import efficiency as indicated by confocal microscopic analysis. This hypersensitivity of malignant cell types to Impβ1 knockdown raises the exciting possibility of anti-cancer therapies targeted at Impβ1.
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Nuclear import factor transportin and arginine methyltransferase 1 modify FUS neurotoxicity in Drosophila. Neurobiol Dis 2014; 74:76-88. [PMID: 25447237 DOI: 10.1016/j.nbd.2014.11.003] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Revised: 10/14/2014] [Accepted: 11/03/2014] [Indexed: 12/13/2022] Open
Abstract
Inclusions containing Fused in Sarcoma (FUS) are found in familial and sporadic cases of the incurable progressive motor neuron disease amyotrophic lateral sclerosis and in a common form of dementia, frontotemporal dementia. Most disease-associated mutations are located in the C-terminal proline-tyrosine nuclear localization sequence (PY-NLS) of FUS and impair its nuclear import. It has been shown in cell culture that the nuclear import of FUS is mediated by transportin, which binds the PY-NLS and the last arginine/glycine/glycine-rich (RGG) domain of FUS. Methylation of this last RGG domain by protein arginine methyltransferases (PRMTs) weakens transportin binding and therefore impairs nuclear translocation of FUS. To investigate the requirements for the nuclear import of FUS in an in vivo model, we generated different transgenic Drosophila lines expressing human FUS wild type (hFUS wt) and two disease-related variants P525L and R495X, in which the NLS is mutated or completely absent, respectively. To rule out effects caused by heterologous hFUS expression, we analysed the corresponding variants for the Drosophila FUS orthologue Cabeza (Caz wt, P398L, Q349X). Expression of these variants in eyes and motor neurons confirmed the PY-NLS-dependent nuclear localization of FUS/Caz and caused neurodegenerative effects. Surprisingly, FUS/Caz toxicity was correlated to the degree of its nuclear localization in this overexpression model. High levels of nuclear FUS/Caz became insoluble and reduced the endogenous Caz levels, confirming FUS autoregulation in Drosophila. RNAi-mediated knockdown of the two transportin orthologues interfered with the nuclear import of FUS/Caz and also enhanced the eye phenotype. Finally, we screened the Drosophila PRMT proteins (DART1-9) and found that knockdown of Dart1 led to a reduction in methylation of hFUS P525L and aggravated its phenotype. These findings show that the molecular mechanisms controlling the nuclear import of FUS/Caz and FUS autoregulation are conserved between humans and Drosophila. In addition to the well-known neurodegenerative effects of FUS loss-of function, our data suggest toxic potential of overexpressed FUS in the nucleus and of insoluble FUS.
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Kimura M, Imamoto N. Biological significance of the importin-β family-dependent nucleocytoplasmic transport pathways. Traffic 2014; 15:727-48. [PMID: 24766099 DOI: 10.1111/tra.12174] [Citation(s) in RCA: 102] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Revised: 04/22/2014] [Accepted: 04/22/2014] [Indexed: 12/19/2022]
Abstract
Importin-β family proteins (Imp-βs) are nucleocytoplasmic transport receptors (NTRs) that import and export proteins and RNAs through the nuclear pores. The family consists of 14-20 members depending on the biological species, and each member transports a specific group of cargoes. Thus, the Imp-βs mediate multiple, parallel transport pathways that can be regulated separately. In fact, the spatiotemporally differential expressions and the functional regulations of Imp-βs have been reported. Additionally, the biological significance of each pathway has been characterized by linking the function of a member of Imp-βs to a cellular consequence. Connecting these concepts, the regulation of the transport pathways conceivably induces alterations in the cellular physiological states. However, few studies have linked the regulation of an importin-β family NTR to an induced cellular response and the corresponding cargoes, despite the significance of this linkage in comprehending the biological relevance of the transport pathways. This review of recent reports on the regulation and biological functions of the Imp-βs highlights the significance of the transport pathways in physiological contexts and points out the possibility that the identification of yet unknown specific cargoes will reinforce the importance of transport regulation.
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Affiliation(s)
- Makoto Kimura
- Cellular Dynamics Laboratory, RIKEN, Hirosawa 2-1, Wako, Saitama, 351-0198, Japan
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Twyffels L, Gueydan C, Kruys V. Transportin-1 and Transportin-2: protein nuclear import and beyond. FEBS Lett 2014; 588:1857-68. [PMID: 24780099 DOI: 10.1016/j.febslet.2014.04.023] [Citation(s) in RCA: 84] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2014] [Revised: 04/12/2014] [Accepted: 04/16/2014] [Indexed: 12/22/2022]
Abstract
Nearly 20 years after its identification as a new β-karyopherin mediating the nuclear import of the RNA-binding protein hnRNP A1, Transportin-1 is still commonly overlooked in comparison with its best known cousin, Importin-β. Transportin-1 is nonetheless a considerable player in nucleo-cytoplasmic transport. Over the past few years, significant progress has been made in the characterization of the nuclear localization signals (NLSs) that Transportin-1 recognizes, thereby providing the molecular basis of its diversified repertoire of cargoes. The recent discovery that mutations in the Transportin-dependent NLS of FUS cause mislocalization of this protein and result in amyotrophic lateral sclerosis illustrates the importance of Transportin-dependent import for human health. Besides, new functions of Transportin-1 are emerging in processes other than nuclear import. Here, we summarize what is known about Transportin-1 and the related β-karyopherin Transportin-2.
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Affiliation(s)
- Laure Twyffels
- Laboratoire de Biologie moléculaire du gène (CP300), Faculté des Sciences, Université Libre de Bruxelles (ULB), Belgium; Center for Microscopy and Molecular Imaging (CMMI), 6041 Gosselies, Belgium.
| | - Cyril Gueydan
- Laboratoire de Biologie moléculaire du gène (CP300), Faculté des Sciences, Université Libre de Bruxelles (ULB), Belgium
| | - Véronique Kruys
- Laboratoire de Biologie moléculaire du gène (CP300), Faculté des Sciences, Université Libre de Bruxelles (ULB), Belgium; Center for Microscopy and Molecular Imaging (CMMI), 6041 Gosselies, Belgium
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40
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Twyffels L, Wauquier C, Soin R, Decaestecker C, Gueydan C, Kruys V. A masked PY-NLS in Drosophila TIS11 and its mammalian homolog tristetraprolin. PLoS One 2013; 8:e71686. [PMID: 23951221 PMCID: PMC3739726 DOI: 10.1371/journal.pone.0071686] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Accepted: 07/07/2013] [Indexed: 12/11/2022] Open
Abstract
Many RNA-binding proteins (RBPs) dynamically shuttle between the nucleus and the cytoplasm, often exerting different functions in each compartment. Therefore, the nucleo-cytoplasmic distribution of RBPs has a strong impact on their activity. Here we describe the localization and the shuttling properties of the tandem zinc finger RBP dTIS11, which is the Drosophila homolog of mammalian TIS11 proteins. Drosophila and mammalian TIS11 proteins act as destabilizing factors in ARE-mediated decay. At equilibrium, dTIS11 is concentrated mainly in the cytoplasm. We show that dTIS11 is a nucleo-cytoplasmic shuttling protein whose nuclear export is mediated by the exportin CRM1 through the recognition of a nuclear export signal (NES) located in a different region comparatively to its mammalian homologs. We also identify a cryptic Transportin-dependent PY nuclear localization signal (PY-NLS) in the tandem zinc finger region of dTIS11 and show that it is conserved across the TIS11 protein family. This NLS partially overlaps the second zinc finger ZnF2. Importantly, mutations disrupting the capacity of the ZnF2 to coordinate a Zinc ion unmask dTIS11 and TTP NLS and promote nuclear import. All together, our results indicate that the nuclear export of TIS11 proteins is mediated by CRM1 through diverging NESs, while their nuclear import mechanism may rely on a highly conserved PY-NLS whose activity is negatively regulated by ZnF2 folding.
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Affiliation(s)
- Laure Twyffels
- Laboratoire de Biologie Moléculaire du Gène, Faculté des Sciences, Université Libre de Bruxelles (ULB), Gosselies, Belgium
- Center for Microscopy and Molecular Imaging, Gosselies, Belgium
| | - Corinne Wauquier
- Laboratoire de Biologie Moléculaire du Gène, Faculté des Sciences, Université Libre de Bruxelles (ULB), Gosselies, Belgium
| | - Romuald Soin
- Laboratoire de Biologie Moléculaire du Gène, Faculté des Sciences, Université Libre de Bruxelles (ULB), Gosselies, Belgium
| | - Christine Decaestecker
- Center for Microscopy and Molecular Imaging, Gosselies, Belgium
- Laboratory of Image Synthesis and Analysis - Ecole Polytechnique de Bruxelles, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Cyril Gueydan
- Laboratoire de Biologie Moléculaire du Gène, Faculté des Sciences, Université Libre de Bruxelles (ULB), Gosselies, Belgium
| | - Véronique Kruys
- Laboratoire de Biologie Moléculaire du Gène, Faculté des Sciences, Université Libre de Bruxelles (ULB), Gosselies, Belgium
- Center for Microscopy and Molecular Imaging, Gosselies, Belgium
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Ye W, Lin W, Tartakoff AM, Ma Q, Tao T. Nuclear import of aristaless-related homeobox protein via its NLS1 regulates its transcriptional function. Mol Cell Biochem 2013; 381:221-31. [PMID: 23771350 DOI: 10.1007/s11010-013-1706-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2012] [Accepted: 05/24/2013] [Indexed: 10/26/2022]
Abstract
Nucleocytoplasmic transport of transcription factors is essential in eukaryotes. We previously reported the presence of two functional NLSs in the homeodomain protein, aristaless-related homeobox (Arx) protein, which is a key transcriptional repressor of LMO1, SHOX2, and PAX4 during development. NLS2, that overlaps the homeodomain, is recognized directly by multiple importin βs, but not by importin αs. In this study, we found that the N-terminal NLS1 of Arx is targeted by multiple importin α proteins, including importin α3 and α5. Both in vivo and in vitro assays demonstrated that nuclear import of Arx via NLS1 is mediated by the importin α/β pathway. Mutagenesis analysis indicated that two basic amino acids, (84)K and (87)R, are essential to the function of NLS1, and that their mutation prevents interactions of Arx with importin αs. Interestingly, inhibition of nuclear import of Arx via NLS1 clearly attenuates its ability of transcriptional repression, suggesting that nuclear import of Arx via NLS1 contributes to its transcriptional function.
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Affiliation(s)
- Wenduo Ye
- Xiamen University School of Life Sciences, Xiamen, Fujian, China
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Expression and subcellular distribution of imp13 are regulated in brain development. In Vitro Cell Dev Biol Anim 2013; 49:346-53. [PMID: 23605716 PMCID: PMC3651826 DOI: 10.1007/s11626-013-9599-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2012] [Accepted: 03/11/2013] [Indexed: 01/12/2023]
Abstract
Imp13, a member of importin-β superfamily, is found to be one of two bidirectional transport receptors in many nuclear transport activities in mammals. Several cargoes of imp13 have been identified; most of these are essential factors involved in cell cycle and development. The expression and localization of imp13 may influence its cargoes in playing their roles in appropriate time and space. To gain insight into the role of imp13 in brain development, we generated an anti-imp13 polyclonal antibody and investigated the expressions of imp13 in mouse embryonic brains during development, including E13.5, E15.5, E17.5, P0, and adult, at both transcriptional and translational levels. In addition, we performed immunohistochemical analysis and revealed that imp13 tends to be localized in the cytoplasm at the early stages and relocates into the nucleus at the late stages in neuronal cells of mouse brains. These findings suggested that the expression and localization of imp13 in brain tissues are regulated developmentally, which extends our knowledge of the dynamic presence of imp13. These observations also imply that imp13 contributes to the neural cell-specific cargo trafficking and potentially to other functions during brain development.
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Sumoylation regulates Kap114-mediated nuclear transport. EMBO J 2012; 31:2461-72. [PMID: 22562154 DOI: 10.1038/emboj.2012.102] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2011] [Accepted: 03/28/2012] [Indexed: 11/08/2022] Open
Abstract
The nuclear import receptor Kap114 carries transcription factors and other cargos across nuclear pores into the nucleus. Here we show that yeast Kap114 is modified by SUMO (small ubiquitin-related modifier) and that sumoylation is required for Kap114-mediated nuclear import. Among the four known SUMO-specific E3 ligases in yeast, Mms21 is the preferred E3 enzyme responsible for the covalent attachment of SUMO to the Kap114 protein. Kap114 is sumoylated on lysine residue 909, which is part of a ΨKxD/E sumoylation consensus motif. Kap114 containing a lysine-to-arginine point mutation at position 909 mislocalizes to the nucleus and is defective in promoting nuclear import. Similarly, mutants defective in sumoylation or desumoylation specifically accumulate Kap114 in the nucleus and are blocked in import of Kap114 cargos. Ran-GTP is not sufficient to disassemble Kap114/cargo complexes, which necessitates additional cargo release mechanisms in the nucleus. Remarkably, sumoylation of Kap114 greatly stimulates cargo dissociation in vitro. We propose that sumoylation occurs at the site of Kap114 cargo function and that SUMO is a cargo release factor involved in intranuclear targeting.
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Miyamoto Y, Boag PR, Hime GR, Loveland KL. Regulated nucleocytoplasmic transport during gametogenesis. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2012; 1819:616-30. [PMID: 22326858 DOI: 10.1016/j.bbagrm.2012.01.015] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2011] [Revised: 01/23/2012] [Accepted: 01/24/2012] [Indexed: 12/13/2022]
Abstract
Gametogenesis is the process by which sperm or ova are produced in the gonads. It is governed by a tightly controlled series of gene expression events, with some common and others distinct for males and females. Nucleocytoplasmic transport is of central importance to the fidelity of gene regulation that is required to achieve the precisely regulated germ cell differentiation essential for fertility. In this review we discuss the physiological importance for gamete formation of the molecules involved in classical nucleocytoplasmic protein transport, including importins/karyopherins, Ran and nucleoporins. To address what functions/factors are conserved or specialized for these developmental processes between species, we compare knowledge from mice, flies and worms. The present analysis provides evidence of the necessity for and specificity of each nuclear transport factor and for nucleoporins during germ cell differentiation. This article is part of a Special Issue entitled: Nuclear Transport and RNA Processing.
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Affiliation(s)
- Yoichi Miyamoto
- Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Monash University, Clayton, Victoria 3800, Australia.
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45
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van der Watt PJ, Leaner VD. The nuclear exporter, Crm1, is regulated by NFY and Sp1 in cancer cells and repressed by p53 in response to DNA damage. BIOCHIMICA ET BIOPHYSICA ACTA 2011; 1809:316-26. [PMID: 21683812 DOI: 10.1016/j.bbagrm.2011.05.017] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2011] [Revised: 05/20/2011] [Accepted: 05/27/2011] [Indexed: 01/19/2023]
Abstract
The nuclear exporter protein, Crm1, plays a key role in normal cell functioning, mediating the nucleo-cytoplasmic transport of cargo proteins. Elevated Crm1 expression has recently been identified in various tumours; however, the mechanisms driving its expression have not been investigated to date. In this study we identified the Crm1 promoter and factors associated with its elevated expression and with its repression under conditions of DNA damage. The -1405 to +99 Crm1 promoter region was found to be significantly more active in cancer and transformed cells compared to normal, and the -175 to +99 region identified as responsible for the differential activity. Mutation of two CCAAT boxes and a GC box within this region significantly diminished Crm1 promoter activity and ChIP analysis revealed binding of NFY and Sp1 to these sites, with increased binding in transformed and cancer cells. In addition, p53 was found to repress Crm1 promoter activity, after induction with doxorubicin, with p53 siRNA blocking the effect. Crm1 promoter constructs with mutated CCAAT boxes were significantly less responsive to p53 repression, and in vivo binding of NFY to the CCAAT boxes was diminished upon p53 binding, suggesting that p53 mediates repression of the Crm1 promoter via interfering with NFY. This was confirmed using NFY knock-down cells, in which Crm1 promoter activity was significantly less responsive to p53. In vitro EMSAs revealed that NFY and p53 bind the CCAAT boxes as a single complex under conditions of DNA damage. In summary, this study is a first to analyse Crm1 promoter regulation and reveals NFY and Sp1 as contributors to Crm1 overexpression in cancer. In addition, this study reveals that Crm1 transcription is inhibited by DNA damage and that the mechanism of inhibition involves p53 interfering with NFY function.
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Affiliation(s)
- Pauline J van der Watt
- Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
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46
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O'Reilly AJ, Dacks JB, Field MC. Evolution of the karyopherin-β family of nucleocytoplasmic transport factors; ancient origins and continued specialization. PLoS One 2011; 6:e19308. [PMID: 21556326 PMCID: PMC3083441 DOI: 10.1371/journal.pone.0019308] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2011] [Accepted: 03/29/2011] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Macromolecular transport across the nuclear envelope (NE) is achieved through nuclear pore complexes (NPCs) and requires karyopherin-βs (KAP-βs), a family of soluble receptors, for recognition of embedded transport signals within cargo. We recently demonstrated, through proteomic analysis of trypanosomes, that NPC architecture is likely highly conserved across the Eukaryota, which in turn suggests conservation of the transport mechanisms. To determine if KAP-β diversity was similarly established early in eukaryotic evolution or if it was subsequently layered onto a conserved NPC, we chose to identify KAP-β sequences in a diverse range of eukaryotes and to investigate their evolutionary history. RESULTS Thirty six predicted proteomes were scanned for candidate KAP-β family members. These resulting sequences were resolved into fifteen KAP-β subfamilies which, due to broad supergroup representation, were most likely represented in the last eukaryotic common ancestor (LECA). Candidate members of each KAP-β subfamily were found in all eukaryotic supergroups, except XPO6, which is absent from Archaeplastida. Phylogenetic reconstruction revealed the likely evolutionary relationships between these different subfamilies. Many species contain more than one representative of each KAP-β subfamily; many duplications are apparently taxon-specific but others result from duplications occurring earlier in eukaryotic history. CONCLUSIONS At least fifteen KAP-β subfamilies were established early in eukaryote evolution and likely before the LECA. In addition we identified expansions at multiple stages within eukaryote evolution, including a multicellular plant-specific KAP-β, together with frequent secondary losses. Taken with evidence for early establishment of NPC architecture, these data demonstrate that multiple pathways for nucleocytoplasmic transport were established prior to the radiation of modern eukaryotes but that selective pressure continues to sculpt the KAP-β family.
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Affiliation(s)
- Amanda J. O'Reilly
- Department of Pathology, University of
Cambridge, Tennis Court Road, Cambridge, United Kingdom
| | - Joel B. Dacks
- Department of Cell Biology, University of
Alberta, Edmonton, Canada
| | - Mark C. Field
- Department of Pathology, University of
Cambridge, Tennis Court Road, Cambridge, United Kingdom
- * E-mail:
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Importin β-type nuclear transport receptors have distinct binding affinities for Ran-GTP. Biochem Biophys Res Commun 2011; 406:383-8. [PMID: 21329658 DOI: 10.1016/j.bbrc.2011.02.051] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2011] [Accepted: 02/11/2011] [Indexed: 01/25/2023]
Abstract
Cargos destined to enter or leave the cell nucleus are typically transported by receptors of the importin β family to pass the nuclear pore complex. The yeast Saccharomyces cerevisiae comprises 14 members of this protein family, which can be divided in importins and exportins. The Ran GTPase regulates the association and dissociation of receptors and cargos as well as the transport direction through the nuclear pore. All receptors bind to Ran exclusively in its GTP-bound state and this event is restricted to the nuclear compartment. We determined the Ran-GTP binding properties of all yeast transport receptors by biosensor measurements and observed that the affinity of importins for Ran-GTP differs significantly. The dissociation constants range from 230 pM to 270 nM, which is mostly based on a variability of the off-rate constants. The divergent affinity of importins for Ran-GTP suggests the existence of a novel mode of nucleocytoplasmic transport regulation. Furthermore, the cellular concentration of β-receptors and of other Ran-binding proteins was determined. We found that the number of β-receptors altogether about equals the amounts of yeast Ran, but Ran-GTP is not limiting in the nucleus. The implications of our results for nucleocytoplasmic transport mechanisms are discussed.
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48
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Ye W, Lin W, Tartakoff AM, Tao T. Karyopherins in nuclear transport of homeodomain proteins during development. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2011; 1813:1654-62. [PMID: 21256166 DOI: 10.1016/j.bbamcr.2011.01.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2010] [Revised: 12/08/2010] [Accepted: 01/09/2011] [Indexed: 01/12/2023]
Abstract
Homeodomain proteins are crucial transcription factors for cell differentiation, cell proliferation and organ development. Interestingly, their homeodomain signature structure is important for both their DNA-binding and their nucleocytoplasmic trafficking. The accurate nucleocytoplasmic distribution of these proteins is essential for their functions. We summarize information on (a) the roles of karyopherins for import and export of homeoproteins, (b) the regulation of their nuclear transport during development, and (c) the corresponding complexity of homeoprotein nucleocytoplasmic transport signals. This article is part of a Special Issue entitled: Regulation of Signaling and Cellular Fate through Modulation of Nuclear Protein Import.
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Affiliation(s)
- Wenduo Ye
- Xiamen University School of Life Sciences, Xiamen, Fujian 361005, China
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Kapon R, Naim B, Zbaida D, Nevo R, Tsabari O, Reich Z. Permeating the nuclear pore complex. Nucleus 2010; 1:475-80. [PMID: 21327089 PMCID: PMC3027049 DOI: 10.4161/nucl.1.6.13112] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2010] [Revised: 06/22/2010] [Accepted: 07/22/2010] [Indexed: 11/19/2022] Open
Abstract
The extensive and multifaceted traffic between nucleus and cytoplasm is handled by a single type of macromolecular assembly called the nuclear pore complex (NPC). While being readily accessible to ions and metabolites, the NPC imposes stringent selectivity on the passage of proteins and RNA, tightly regulating their traffic between the two major cellular compartments. Here we discuss how shuttling carriers, which mediate the transport of macromolecules through NPCs, cross its permeability barrier. We also discuss the co-existence of receptor-mediated macromolecular transport with the passive diffusion of small molecules in the context of the various models suggested for the permeability barrier of the NPC. Finally, we speculate on how nuclear transport receptors negotiate the dependence of their NPC-permeating abilities on hydrophobic interactions with the necessity of avoiding these promiscuous interactions in the cytoplasm and nucleus.
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Affiliation(s)
- Ruti Kapon
- Department of Biological Chemistry; Weizmann Institute of Science; Rehovot Israel
| | - Bracha Naim
- Department of Biological Chemistry; Weizmann Institute of Science; Rehovot Israel
| | - David Zbaida
- Department of Materials and Interfaces; Weizmann Institute of Science; Rehovot Israel
| | - Reinat Nevo
- Department of Biological Chemistry; Weizmann Institute of Science; Rehovot Israel
| | - Onie Tsabari
- Department of Biological Chemistry; Weizmann Institute of Science; Rehovot Israel
| | - Ziv Reich
- Department of Biological Chemistry; Weizmann Institute of Science; Rehovot Israel
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Chook YM, Süel KE. Nuclear import by karyopherin-βs: recognition and inhibition. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2010; 1813:1593-606. [PMID: 21029754 DOI: 10.1016/j.bbamcr.2010.10.014] [Citation(s) in RCA: 300] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 07/15/2010] [Revised: 10/06/2010] [Accepted: 10/19/2010] [Indexed: 01/24/2023]
Abstract
Proteins in the karyopherin-β family mediate the majority of macromolecular transport between the nucleus and the cytoplasm. Eleven of the 19 known human karyopherin-βs and 10 of the 14S. cerevisiae karyopherin-βs mediate nuclear import through recognition of nuclear localization signals or NLSs in their cargos. This receptor-mediated process is essential to cellular viability as proteins are translated in the cytoplasm but many have functional roles in the nucleus. Many known karyopherin-β-cargo interactions were discovered through studies of the individual cargos rather than the karyopherins, and this information is thus widely scattered in the literature. We consolidate information about cargos that are directly recognized by import-karyopherin-βs and review common characteristics or lack thereof among cargos of different import pathways. Knowledge of karyopherin-β-cargo interactions is also critical for the development of nuclear import inhibitors and the understanding of their mechanisms of inhibition. This article is part of a Special Issue entitled: Regulation of Signaling and Cellular Fate through Modulation of Nuclear Protein Import.
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Affiliation(s)
- Yuh Min Chook
- Department of Pharmacology, University of Texas Southerwestern Medical Center, Dallas, TX 75206, USA.
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