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Choudhry SK, Neal ML, Li S, Navare AT, Van Eeuwen T, Wozniak RW, Mast FD, Rout MP, Aitchison JD. Nuclear pore complexes mediate subtelomeric gene silencing by regulating PCNA levels on chromatin. J Cell Biol 2023; 222:e202207060. [PMID: 37358474 PMCID: PMC10292210 DOI: 10.1083/jcb.202207060] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Revised: 04/02/2023] [Accepted: 06/07/2023] [Indexed: 06/27/2023] Open
Abstract
The nuclear pore complex (NPC) physically interacts with chromatin and regulates gene expression. The Saccharomyces cerevisiae inner ring nucleoporin Nup170 has been implicated in chromatin organization and the maintenance of gene silencing in subtelomeric regions. To gain insight into how Nup170 regulates this process, we used protein-protein interactions, genetic interactions, and transcriptome correlation analyses to identify the Ctf18-RFC complex, an alternative proliferating cell nuclear antigen (PCNA) loader, as a facilitator of the gene regulatory functions of Nup170. The Ctf18-RFC complex is recruited to a subpopulation of NPCs that lack the nuclear basket proteins Mlp1 and Mlp2. In the absence of Nup170, PCNA levels on DNA are reduced, resulting in the loss of silencing of subtelomeric genes. Increasing PCNA levels on DNA by removing Elg1, which is required for PCNA unloading, rescues subtelomeric silencing defects in nup170Δ. The NPC, therefore, mediates subtelomeric gene silencing by regulating PCNA levels on DNA.
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Affiliation(s)
- Sanjeev Kumar Choudhry
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, WA, USA
| | - Maxwell L. Neal
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, WA, USA
| | - Song Li
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, WA, USA
| | - Arti T. Navare
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, WA, USA
| | - Trevor Van Eeuwen
- Laboratory of Cellular and Structural Biology, The Rockefeller University, New York, NY, USA
| | | | - Fred D. Mast
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, WA, USA
| | - Michael P. Rout
- Laboratory of Cellular and Structural Biology, The Rockefeller University, New York, NY, USA
| | - John D. Aitchison
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, WA, USA
- Departments of Pediatrics and Biochemistry, University of Washington, Seattle, WA, USA
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2
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de Oya IG, Manzano-López J, Álvarez-Llamas A, Vázquez-Aroca MDLP, Cepeda-García C, Monje-Casas F. Characterization of a novel interaction of the Nup159 nucleoporin with asymmetrically localized spindle pole body proteins and its link with autophagy. PLoS Biol 2023; 21:e3002224. [PMID: 37535687 PMCID: PMC10437821 DOI: 10.1371/journal.pbio.3002224] [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: 05/18/2022] [Revised: 08/18/2023] [Accepted: 06/28/2023] [Indexed: 08/05/2023] Open
Abstract
Both the spindle microtubule-organizing centers and the nuclear pore complexes (NPCs) are convoluted structures where many signaling pathways converge to coordinate key events during cell division. Interestingly, despite their distinct molecular conformation and overall functions, these structures share common components and collaborate in the regulation of essential processes. We have established a new link between microtubule-organizing centers and nuclear pores in budding yeast by unveiling an interaction between the Bfa1/Bub2 complex, a mitotic exit inhibitor that localizes on the spindle pole bodies, and the Nup159 nucleoporin. Bfa1/Bub2 association with Nup159 is reduced in metaphase to not interfere with proper spindle positioning. However, their interaction is stimulated in anaphase and assists the Nup159-dependent autophagy pathway. The asymmetric localization of Bfa1/Bub2 during mitosis raises the possibility that its interaction with Nup159 could differentially promote Nup159-mediated autophagic processes, which might be relevant for the maintenance of the replicative lifespan.
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Affiliation(s)
- Inés García de Oya
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER) / Spanish National Research Council (CSIC) - University of Seville - University Pablo de Olavide, Sevilla, Spain
| | - Javier Manzano-López
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER) / Spanish National Research Council (CSIC) - University of Seville - University Pablo de Olavide, Sevilla, Spain
| | - Alejandra Álvarez-Llamas
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER) / Spanish National Research Council (CSIC) - University of Seville - University Pablo de Olavide, Sevilla, Spain
| | - María de la Paz Vázquez-Aroca
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER) / Spanish National Research Council (CSIC) - University of Seville - University Pablo de Olavide, Sevilla, Spain
| | - Cristina Cepeda-García
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER) / Spanish National Research Council (CSIC) - University of Seville - University Pablo de Olavide, Sevilla, Spain
| | - Fernando Monje-Casas
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER) / Spanish National Research Council (CSIC) - University of Seville - University Pablo de Olavide, Sevilla, Spain
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3
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Santana-Sosa S, Matos-Perdomo E, Ayra-Plasencia J, Machín F. A Yeast Mitotic Tale for the Nucleus and the Vacuoles to Embrace. Int J Mol Sci 2023; 24:9829. [PMID: 37372977 DOI: 10.3390/ijms24129829] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Revised: 06/02/2023] [Accepted: 06/03/2023] [Indexed: 06/29/2023] Open
Abstract
The morphology of the nucleus is roughly spherical in most eukaryotic cells. However, this organelle shape needs to change as the cell travels through narrow intercellular spaces during cell migration and during cell division in organisms that undergo closed mitosis, i.e., without dismantling the nuclear envelope, such as yeast. In addition, the nuclear morphology is often modified under stress and in pathological conditions, being a hallmark of cancer and senescent cells. Thus, understanding nuclear morphological dynamics is of uttermost importance, as pathways and proteins involved in nuclear shaping can be targeted in anticancer, antiaging, and antifungal therapies. Here, we review how and why the nuclear shape changes during mitotic blocks in yeast, introducing novel data that associate these changes with both the nucleolus and the vacuole. Altogether, these findings suggest a close relationship between the nucleolar domain of the nucleus and the autophagic organelle, which we also discuss here. Encouragingly, recent evidence in tumor cell lines has linked aberrant nuclear morphology to defects in lysosomal function.
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Affiliation(s)
- Silvia Santana-Sosa
- Research Unit, University Hospital Ntra Sra de Candelaria, Ctra del Rosario 145, 38010 Santa Cruz de Tenerife, Spain
- Institute of Biomedical Technologies, University of La Laguna, 38200 San Cristóbal de La Laguna, Spain
| | - Emiliano Matos-Perdomo
- Research Unit, University Hospital Ntra Sra de Candelaria, Ctra del Rosario 145, 38010 Santa Cruz de Tenerife, Spain
- Institute of Biomedical Technologies, University of La Laguna, 38200 San Cristóbal de La Laguna, Spain
| | - Jessel Ayra-Plasencia
- Research Unit, University Hospital Ntra Sra de Candelaria, Ctra del Rosario 145, 38010 Santa Cruz de Tenerife, Spain
- Institute of Biomedical Technologies, University of La Laguna, 38200 San Cristóbal de La Laguna, Spain
| | - Félix Machín
- Research Unit, University Hospital Ntra Sra de Candelaria, Ctra del Rosario 145, 38010 Santa Cruz de Tenerife, Spain
- Institute of Biomedical Technologies, University of La Laguna, 38200 San Cristóbal de La Laguna, Spain
- Faculty of Health Sciences, Fernando Pessoa Canarias University, 35450 Santa María de Guía, Spain
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4
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Integrated Transcriptome and Targeted Metabolite Analysis Reveal miRNA-mRNA Networks in Low-Light-Induced Lotus Flower Bud Abortion. Int J Mol Sci 2022; 23:ijms23179925. [PMID: 36077323 PMCID: PMC9456346 DOI: 10.3390/ijms23179925] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 08/21/2022] [Accepted: 08/23/2022] [Indexed: 11/16/2022] Open
Abstract
Most Nelumbo nucifera (lotus) flower buds were aborted during the growing season, notably in low-light environments. How lotus produces so many aborted flower buds is largely unknown. An integrated transcriptome and targeted metabolite analysis was performed to reveal the genetic regulatory networks underlying lotus flower bud abortion. A total of 233 miRNAs and 25,351 genes were identified in lotus flower buds, including 68 novel miRNAs and 1108 novel genes. Further enrichment analysis indicated that sugar signaling plays a potential central role in regulating lotus flower bud abortion. Targeted metabolite analysis showed that trehalose levels declined the most in the aborting flower buds. A potential regulatory network centered on miR156 governs lotus flower bud abortion, involving multiple miRNA-mRNA pairs related to cell integrity, cell proliferation and expansion, and DNA repair. Genetic analysis showed that miRNA156-5p-overexpressing lotus showed aggravated flower bud abortion phenotypes. Trehalose-6-P synthase 1 (TPS1), which is required for trehalose synthase, had a negative regulatory effect on miR156 expression. TPS1-overexpression lotus showed significantly decreased flower bud abortion rates both in normal-light and low-light environments. Our study establishes a possible genetic basis for how lotus produces so many aborted flower buds, facilitating genetic improvement of lotus’ shade tolerance.
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5
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Nuclear mRNA Export and Aging. Int J Mol Sci 2022; 23:ijms23105451. [PMID: 35628261 PMCID: PMC9142925 DOI: 10.3390/ijms23105451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Revised: 05/10/2022] [Accepted: 05/12/2022] [Indexed: 02/04/2023] Open
Abstract
The relationship between transcription and aging is one that has been studied intensively and experimentally with diverse attempts. However, the impact of the nuclear mRNA export on the aging process following its transcription is still poorly understood, although the nuclear events after transcription are coupled closely with the transcription pathway because the essential factors required for mRNA transport, namely TREX, TREX-2, and nuclear pore complex (NPC), physically and functionally interact with various transcription factors, including the activator/repressor and pre-mRNA processing factors. Dysregulation of the mediating factors for mRNA export from the nucleus generally leads to the aberrant accumulation of nuclear mRNA and further impairment in the vegetative growth and normal lifespan and the pathogenesis of neurodegenerative diseases. The optimal stoichiometry and density of NPC are destroyed during the process of cellular aging, and their damage triggers a defect of function in the nuclear permeability barrier. This review describes recent findings regarding the role of the nuclear mRNA export in cellular aging and age-related neurodegenerative disorders.
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6
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Deolal P, Jamir I, Mishra K. Uip4p modulates nuclear pore complex function in Saccharomyces cerevisiae. Nucleus 2022; 13:79-93. [PMID: 35171083 PMCID: PMC8855845 DOI: 10.1080/19491034.2022.2034286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
A double membrane bilayer perforated by nuclear pore complexes (NPCs) governs the shape of the nucleus, the prominent distinguishing organelle of a eukaryotic cell. Despite the absence of lamins in yeasts, the nuclear morphology is stably maintained and shape changes occur in a regulated fashion. In a quest to identify factors that contribute to regulation of nuclear shape and function in Saccharomyces cerevisiae, we used a fluorescence imaging based approach. Here we report the identification of a novel protein, Uip4p, that is required for regulation of nuclear morphology. Loss of Uip4 compromises NPC function and loss of nuclear envelope (NE) integrity. Our localization studies show that Uip4 localizes to the NE and endoplasmic reticulum (ER) network. Furthermore, we demonstrate that the localization and expression of Uip4 is regulated during growth, which is crucial for NPC distribution.
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Affiliation(s)
- Pallavi Deolal
- Department of Biochemistry, School of Life Sciences, University of Hyderabad, Hyderabad, India
| | - Imlitoshi Jamir
- Department of Biotechnology, School of Engineering and Technology, Nagaland University, Dimapur, India
| | - Krishnaveni Mishra
- Department of Biochemistry, School of Life Sciences, University of Hyderabad, Hyderabad, India
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7
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Davis LK, Ford IJ, Hoogenboom BW. Crowding-induced phase separation of nuclear transport receptors in FG nucleoporin assemblies. eLife 2022; 11:e72627. [PMID: 35098921 PMCID: PMC8880993 DOI: 10.7554/elife.72627] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Accepted: 01/28/2022] [Indexed: 11/13/2022] Open
Abstract
The rapid (<1 ms) transport of biological material to and from the cell nucleus is regulated by the nuclear pore complex (NPC). At the core of the NPC is a permeability barrier consisting of intrinsically disordered phenylalanine-glycine nucleoporins (FG Nups). Various types of nuclear transport receptors (NTRs) facilitate transport by partitioning in the FG Nup assembly, overcoming the barrier by their affinity to the FG Nups, and comprise a significant fraction of proteins in the NPC barrier. In previous work (Zahn et al., 2016), we revealed a universal physical behaviour in the experimentally observed binding of two well-characterised NTRs, Nuclear Transport Factor 2 (NTF2) and the larger Importin-β (Imp-β), to different planar assemblies of FG Nups, with the binding behaviour defined by negative cooperativity. This was further validated by a minimal physical model that treated the FG Nups as flexible homopolymers and the NTRs as uniformly cohesive spheres. Here, we build upon our original study by first parametrising our model to experimental data, and next predicting the effects of crowding by different types of NTRs. We show how varying the amounts of one type of NTR modulates how the other NTR penetrates the FG Nup assembly. Notably, at similar and physiologically relevant NTR concentrations, our model predicts demixed phases of NTF2 and Imp-β within the FG Nup assembly. The functional implication of NTR phase separation is that NPCs may sustain separate transport pathways that are determined by inter-NTR competition.
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Affiliation(s)
- Luke K Davis
- Department of Physics and Astronomy, University College LondonLondonUnited Kingdom
- Institute for the Physics of Living Systems, University College LondonLondonUnited Kingdom
- London Centre for Nanotechnology, University College LondonLondonUnited Kingdom
| | - Ian J Ford
- Department of Physics and Astronomy, University College LondonLondonUnited Kingdom
- Institute for the Physics of Living Systems, University College LondonLondonUnited Kingdom
- London Centre for Nanotechnology, University College LondonLondonUnited Kingdom
| | - Bart W Hoogenboom
- Department of Physics and Astronomy, University College LondonLondonUnited Kingdom
- Institute for the Physics of Living Systems, University College LondonLondonUnited Kingdom
- London Centre for Nanotechnology, University College LondonLondonUnited Kingdom
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8
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Bindra D, Mishra RK. In Pursuit of Distinctiveness: Transmembrane Nucleoporins and Their Disease Associations. Front Oncol 2022; 11:784319. [PMID: 34970494 PMCID: PMC8712647 DOI: 10.3389/fonc.2021.784319] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 11/25/2021] [Indexed: 11/13/2022] Open
Abstract
The bi-directional nucleocytoplasmic shuttling of macromolecules like molecular signals, transcription factors, regulatory proteins, and RNAs occurs exclusively through Nuclear Pore Complex (NPC) residing in the nuclear membrane. This magnanimous complex is essentially a congregation of ~32 conserved proteins termed Nucleoporins (Nups) present in multiple copies and mostly arranged as subcomplexes to constitute a functional NPC. Nups participate in ancillary functions such as chromatin organization, transcription regulation, DNA damage repair, genome stabilization, and cell cycle control, apart from their central role as nucleocytoplasmic conduits. Thus, Nups exert a role in the maintenance of cellular homeostasis. In mammals, precisely three nucleoporins traverse the nuclear membrane, are called transmembrane Nups (TM-Nups), and are involved in multiple cellular functions. Owing to their vital roles in cellular processes and homeostasis, dysregulation of nucleoporin function is implicated in various diseases. The deregulated functioning of TM-Nups can thus act as an opportune window for the development of diseases. Indeed, mounting evidence exhibits a strong association of TM-Nups in cancer and numerous other physiological disorders. These findings have provided much-needed insights into the novel mechanisms of disease progression. While nucleoporin’s functions have often been summarized in the disease context, a focus on TM-Nups has always lacked. This review emphasizes the elucidation of distinct canonical and non-canonical functions of mammalian TM-Nups and the underlying mechanisms of their disease association.
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Affiliation(s)
- Divya Bindra
- Nups and SUMO Biology Group, Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Bhopal, Bhopal, India
| | - Ram Kumar Mishra
- Nups and SUMO Biology Group, Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Bhopal, Bhopal, India
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9
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Padilla-Mejia NE, Makarov AA, Barlow LD, Butterfield ER, Field MC. Evolution and diversification of the nuclear envelope. Nucleus 2021; 12:21-41. [PMID: 33435791 PMCID: PMC7889174 DOI: 10.1080/19491034.2021.1874135] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 12/08/2020] [Accepted: 12/11/2020] [Indexed: 02/06/2023] Open
Abstract
Eukaryotic cells arose ~1.5 billion years ago, with the endomembrane system a central feature, facilitating evolution of intracellular compartments. Endomembranes include the nuclear envelope (NE) dividing the cytoplasm and nucleoplasm. The NE possesses universal features: a double lipid bilayer membrane, nuclear pore complexes (NPCs), and continuity with the endoplasmic reticulum, indicating common evolutionary origin. However, levels of specialization between lineages remains unclear, despite distinct mechanisms underpinning various nuclear activities. Several distinct modes of molecular evolution facilitate organellar diversification and to understand which apply to the NE, we exploited proteomic datasets of purified nuclear envelopes from model systems for comparative analysis. We find enrichment of core nuclear functions amongst the widely conserved proteins to be less numerous than lineage-specific cohorts, but enriched in core nuclear functions. This, together with consideration of additional evidence, suggests that, despite a common origin, the NE has evolved as a highly diverse organelle with significant lineage-specific functionality.
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Affiliation(s)
- Norma E. Padilla-Mejia
- Division of Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dundee, UK
| | - Alexandr A. Makarov
- Division of Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dundee, UK
| | - Lael D. Barlow
- Division of Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dundee, UK
| | - Erin R. Butterfield
- Division of Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dundee, UK
| | - Mark C. Field
- Division of Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dundee, UK
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České, Czech Republic
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10
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Chen M, Long Q, Borrie MS, Sun H, Zhang C, Yang H, Shi D, Gartenberg MR, Deng W. Nucleoporin TPR promotes tRNA nuclear export and protein synthesis in lung cancer cells. PLoS Genet 2021; 17:e1009899. [PMID: 34793452 PMCID: PMC8639082 DOI: 10.1371/journal.pgen.1009899] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 12/02/2021] [Accepted: 10/21/2021] [Indexed: 12/26/2022] Open
Abstract
The robust proliferation of cancer cells requires vastly elevated levels of protein synthesis, which relies on a steady supply of aminoacylated tRNAs. Delivery of tRNAs to the cytoplasm is a highly regulated process, but the machinery for tRNA nuclear export is not fully elucidated. In this study, using a live cell imaging strategy that visualizes nascent transcripts from a specific tRNA gene in yeast, we identified the nuclear basket proteins Mlp1 and Mlp2, two homologs of the human TPR protein, as regulators of tRNA export. TPR expression is significantly increased in lung cancer tissues and correlated with poor prognosis. Consistently, knockdown of TPR inhibits tRNA nuclear export, protein synthesis and cell growth in lung cancer cell lines. We further show that NXF1, a well-known mRNA nuclear export factor, associates with tRNAs and mediates their transport through nuclear pores. Collectively, our findings uncover a conserved mechanism that regulates nuclear export of tRNAs, which is a limiting step in protein synthesis in eukaryotes.
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Affiliation(s)
- Miao Chen
- State Key Laboratory of Oncology in South China and Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou, Guangdong, China
- Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School, Piscataway, New Jersey, United States of America
| | - Qian Long
- State Key Laboratory of Oncology in South China and Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou, Guangdong, China
| | - Melinda S. Borrie
- Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School, Piscataway, New Jersey, United States of America
| | - Haohui Sun
- State Key Laboratory of Oncology in South China and Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou, Guangdong, China
| | - Changlin Zhang
- State Key Laboratory of Oncology in South China and Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou, Guangdong, China
- Department of Obstetrics and Gynecology, The Seventh Affiliated Hospital of Sun Yat-sen University, Shenzhen, Guangdong, China
| | - Han Yang
- State Key Laboratory of Oncology in South China and Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou, Guangdong, China
| | - Dingbo Shi
- State Key Laboratory of Oncology in South China and Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou, Guangdong, China
| | - Marc R. Gartenberg
- Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School, Piscataway, New Jersey, United States of America
- The Cancer Institute of New Jersey, Rutgers University, New Brunswick, New Jersey, United States of America
| | - Wuguo Deng
- State Key Laboratory of Oncology in South China and Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou, Guangdong, China
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11
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Matsuda A, Mofrad MRK. Free energy calculations shed light on the nuclear pore complex's selective barrier nature. Biophys J 2021; 120:3628-3640. [PMID: 34339633 PMCID: PMC8456294 DOI: 10.1016/j.bpj.2021.07.025] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 05/27/2021] [Accepted: 07/27/2021] [Indexed: 12/27/2022] Open
Abstract
The nuclear pore complex (NPC) is the exclusive gateway for traffic control across the nuclear envelope. Although smaller cargoes (less than 5-9 nm in size) can freely diffuse through the NPC, the passage of larger cargoes is restricted to those accompanied by nuclear transport receptors (NTRs). This selective barrier nature of the NPC is putatively associated with the intrinsically disordered, phenylalanine-glycine repeat-domains containing nucleoporins, termed FG-Nups. The precise mechanism underlying how FG-Nups carry out such an exquisite task at high throughputs has, however, remained elusive and the subject of various hypotheses. From the thermodynamics perspective, free energy analysis can be a way to determine cargo's transportability because the traffic through the NPC must be in the direction of reducing the free energy. In this study, we developed a computational model to evaluate the free energy composed of the conformational entropy of FG-Nups and the energetic gain associated with binding interactions between FG-Nups and NTRs and investigated whether these physical features can be the basis of NPC's selectivity. Our results showed that the reduction in conformational entropy by inserting a cargo into the NPC increased the free energy by an amount substantially greater than the thermal energy (≫kBT), whereas the free energy change was negligible (
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Affiliation(s)
- Atsushi Matsuda
- Molecular Cell Biomechanics Laboratory, Departments of Bioengineering and Mechanical Engineering, University of California Berkeley, Berkeley, California
| | - Mohammad R K Mofrad
- Molecular Cell Biomechanics Laboratory, Departments of Bioengineering and Mechanical Engineering, University of California Berkeley, Berkeley, California; Molecular Biophysics and Integrative Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California.
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12
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Hoogenboom BW, Hough LE, Lemke EA, Lim RYH, Onck PR, Zilman A. Physics of the Nuclear Pore Complex: Theory, Modeling and Experiment. PHYSICS REPORTS 2021; 921:1-53. [PMID: 35892075 PMCID: PMC9306291 DOI: 10.1016/j.physrep.2021.03.003] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The hallmark of eukaryotic cells is the nucleus that contains the genome, enclosed by a physical barrier known as the nuclear envelope (NE). On the one hand, this compartmentalization endows the eukaryotic cells with high regulatory complexity and flexibility. On the other hand, it poses a tremendous logistic and energetic problem of transporting millions of molecules per second across the nuclear envelope, to facilitate their biological function in all compartments of the cell. Therefore, eukaryotes have evolved a molecular "nanomachine" known as the Nuclear Pore Complex (NPC). Embedded in the nuclear envelope, NPCs control and regulate all the bi-directional transport between the cell nucleus and the cytoplasm. NPCs combine high molecular specificity of transport with high throughput and speed, and are highly robust with respect to molecular noise and structural perturbations. Remarkably, the functional mechanisms of NPC transport are highly conserved among eukaryotes, from yeast to humans, despite significant differences in the molecular components among various species. The NPC is the largest macromolecular complex in the cell. Yet, despite its significant complexity, it has become clear that its principles of operation can be largely understood based on fundamental physical concepts, as have emerged from a combination of experimental methods of molecular cell biology, biophysics, nanoscience and theoretical and computational modeling. Indeed, many aspects of NPC function can be recapitulated in artificial mimics with a drastically reduced complexity compared to biological pores. We review the current physical understanding of the NPC architecture and function, with the focus on the critical analysis of experimental studies in cells and artificial NPC mimics through the lens of theoretical and computational models. We also discuss the connections between the emerging concepts of NPC operation and other areas of biophysics and bionanotechnology.
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Affiliation(s)
- Bart W. Hoogenboom
- London Centre for Nanotechnology and Department of Physics and Astronomy, University College London, London WC1E 6BT, United Kingdom
| | - Loren E. Hough
- Department of Physics and BioFrontiers Institute, University of Colorado, Boulder CO 80309, United States of America
| | - Edward A. Lemke
- Biocenter Mainz, Departments of Biology and Chemistry, Johannes Gutenberg University and Institute of Molecular Biology, 55128 Mainz, Germany
| | - Roderick Y. H. Lim
- Biozentrum and the Swiss Nanoscience Institute, University of Basel, 4056 Basel, Switzerland
| | - Patrick R. Onck
- Zernike Institute for Advanced Materials, University of Groningen, 9747 AG Groningen, The Netherlands
| | - Anton Zilman
- Department of Physics and Institute for Biomedical Engineering (IBME), University of Toronto, Toronto, ON M5S 1A7, Canada
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13
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Koch BA, Staley E, Jin H, Yu HG. The ESCRT-III complex is required for nuclear pore complex sequestration and regulates gamete replicative lifespan in budding yeast meiosis. Nucleus 2021; 11:219-236. [PMID: 32893723 PMCID: PMC7529410 DOI: 10.1080/19491034.2020.1812872] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Cellular aging occurs as a cell loses its ability to maintain homeostasis. Aging cells eliminate damaged cellular compartments and other senescence factors via self-renewal. The mechanism that regulates cellular rejuvenation remains to be further elucidated. Using budding yeast gametogenesis as a model, we show here that the endosomal sorting complex required for transport (ESCRT) III regulates nuclear envelope organization. During gametogenesis, the nuclear pore complex (NPC) and other senescence factors are sequestered away from the prospore nuclei. We show that the LEM-domain protein Heh1 (Src1) facilitates the nuclear recruitment of ESCRT-III, which is required for meiotic NPC sequestration and nuclear envelope remodeling. Furthermore, ESCRT-III-mediated nuclear reorganization appears to be critical for gamete rejuvenation, as hindering this process curtails either directly or indirectly the replicative lifespan in gametes. Our findings demonstrate the importance of ESCRT-III in nuclear envelope remodeling and its potential role in eliminating senescence factors during gametogenesis.
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Affiliation(s)
- Bailey A Koch
- Department of Biological Science, The Florida State University , Tallahassee, FL, USA
| | - Elizabeth Staley
- Department of Biological Science, The Florida State University , Tallahassee, FL, USA
| | - Hui Jin
- Department of Biological Science, The Florida State University , Tallahassee, FL, USA
| | - Hong-Guo Yu
- Department of Biological Science, The Florida State University , Tallahassee, FL, USA
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14
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Costanzo M, Hou J, Messier V, Nelson J, Rahman M, VanderSluis B, Wang W, Pons C, Ross C, Ušaj M, San Luis BJ, Shuteriqi E, Koch EN, Aloy P, Myers CL, Boone C, Andrews B. Environmental robustness of the global yeast genetic interaction network. Science 2021; 372:372/6542/eabf8424. [PMID: 33958448 DOI: 10.1126/science.abf8424] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Accepted: 03/30/2021] [Indexed: 12/18/2022]
Abstract
Phenotypes associated with genetic variants can be altered by interactions with other genetic variants (GxG), with the environment (GxE), or both (GxGxE). Yeast genetic interactions have been mapped on a global scale, but the environmental influence on the plasticity of genetic networks has not been examined systematically. To assess environmental rewiring of genetic networks, we examined 14 diverse conditions and scored 30,000 functionally representative yeast gene pairs for dynamic, differential interactions. Different conditions revealed novel differential interactions, which often uncovered functional connections between distantly related gene pairs. However, the majority of observed genetic interactions remained unchanged in different conditions, suggesting that the global yeast genetic interaction network is robust to environmental perturbation and captures the fundamental functional architecture of a eukaryotic cell.
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Affiliation(s)
- Michael Costanzo
- The Donnelly Centre, University of Toronto, 160 College Street, Toronto, ON M5S 3E1, Canada
| | - Jing Hou
- The Donnelly Centre, University of Toronto, 160 College Street, Toronto, ON M5S 3E1, Canada
| | - Vincent Messier
- The Donnelly Centre, University of Toronto, 160 College Street, Toronto, ON M5S 3E1, Canada
| | - Justin Nelson
- Department of Computer Science and Engineering, University of Minnesota-Twin Cities, 200 Union Street, Minneapolis, MN 55455, USA.,Program in Biomedical Informatics and Computational Biology, University of Minnesota-Twin Cities, 200 Union Street, Minneapolis, MN 55455, USA
| | - Mahfuzur Rahman
- Department of Computer Science and Engineering, University of Minnesota-Twin Cities, 200 Union Street, Minneapolis, MN 55455, USA.,Program in Biomedical Informatics and Computational Biology, University of Minnesota-Twin Cities, 200 Union Street, Minneapolis, MN 55455, USA
| | - Benjamin VanderSluis
- Department of Computer Science and Engineering, University of Minnesota-Twin Cities, 200 Union Street, Minneapolis, MN 55455, USA
| | - Wen Wang
- Department of Computer Science and Engineering, University of Minnesota-Twin Cities, 200 Union Street, Minneapolis, MN 55455, USA
| | - Carles Pons
- Institute for Research in Biomedicine (IRB Barcelona), Barcelona Institute for Science and Technology, Barcelona, Spain
| | - Catherine Ross
- The Donnelly Centre, University of Toronto, 160 College Street, Toronto, ON M5S 3E1, Canada
| | - Matej Ušaj
- The Donnelly Centre, University of Toronto, 160 College Street, Toronto, ON M5S 3E1, Canada
| | - Bryan-Joseph San Luis
- The Donnelly Centre, University of Toronto, 160 College Street, Toronto, ON M5S 3E1, Canada
| | - Emira Shuteriqi
- The Donnelly Centre, University of Toronto, 160 College Street, Toronto, ON M5S 3E1, Canada
| | - Elizabeth N Koch
- Department of Computer Science and Engineering, University of Minnesota-Twin Cities, 200 Union Street, Minneapolis, MN 55455, USA
| | - Patrick Aloy
- Institute for Research in Biomedicine (IRB Barcelona), Barcelona Institute for Science and Technology, Barcelona, Spain.,Institució Catalana de Recerca I Estudis Avaçats (ICREA), Barcelona, Spain
| | - Chad L Myers
- Department of Computer Science and Engineering, University of Minnesota-Twin Cities, 200 Union Street, Minneapolis, MN 55455, USA. .,Program in Biomedical Informatics and Computational Biology, University of Minnesota-Twin Cities, 200 Union Street, Minneapolis, MN 55455, USA
| | - Charles Boone
- The Donnelly Centre, University of Toronto, 160 College Street, Toronto, ON M5S 3E1, Canada. .,Department of Molecular Genetics, University of Toronto, 160 College Street, Toronto, ON M5S 3E1, Canada.,RIKEN Center for Sustainable Resource Science, Wako, Saitama, Japan
| | - Brenda Andrews
- The Donnelly Centre, University of Toronto, 160 College Street, Toronto, ON M5S 3E1, Canada. .,Department of Molecular Genetics, University of Toronto, 160 College Street, Toronto, ON M5S 3E1, Canada
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15
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Tomioka Y, Kotani T, Kirisako H, Oikawa Y, Kimura Y, Hirano H, Ohsumi Y, Nakatogawa H. TORC1 inactivation stimulates autophagy of nucleoporin and nuclear pore complexes. J Cell Biol 2021; 219:151819. [PMID: 32453403 PMCID: PMC7337488 DOI: 10.1083/jcb.201910063] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 03/05/2020] [Accepted: 04/20/2020] [Indexed: 02/08/2023] Open
Abstract
The mechanisms underlying turnover of the nuclear pore complex (NPC) and the component nucleoporins (Nups) are still poorly understood. In this study, we found that the budding yeast Saccharomyces cerevisiae triggers NPC degradation by autophagy upon the inactivation of Tor kinase complex 1. This degradation largely depends on the selective autophagy-specific factor Atg11 and the autophagy receptor-binding ability of Atg8, suggesting that the NPC is degraded via receptor-dependent selective autophagy. Immunoelectron microscopy revealed that NPCs embedded in nuclear envelope-derived double-membrane vesicles are sequestered within autophagosomes. At least two pathways are involved in NPC degradation: Atg39-dependent nucleophagy (selective autophagy of the nucleus) and a pathway involving an unknown receptor. In addition, we found the interaction between Nup159 and Atg8 via the Atg8-family interacting motif is important for degradation of this nucleoporin not assembled into the NPC. Thus, this study provides the first evidence for autophagic degradation of the NPC and Nups, which we term "NPC-phagy" and "nucleoporinophagy."
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Affiliation(s)
- Yui Tomioka
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
| | - Tetsuya Kotani
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
| | - Hiromi Kirisako
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
| | - Yu Oikawa
- Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan
| | - Yayoi Kimura
- Advanced Medical Research Center, Yokohama City University, Yokohama, Japan
| | - Hisashi Hirano
- Advanced Medical Research Center, Yokohama City University, Yokohama, Japan
| | - Yoshinori Ohsumi
- Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan
| | - Hitoshi Nakatogawa
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
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16
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Kim M, van Hoof A. Suppressors of mRNA Decapping Defects Restore Growth Without Major Effects on mRNA Decay Rates or Abundance. Genetics 2020; 216:1051-1069. [PMID: 32998951 PMCID: PMC7768250 DOI: 10.1534/genetics.120.303641] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Accepted: 09/28/2020] [Indexed: 01/09/2023] Open
Abstract
Faithful degradation of mRNAs is a critical step in gene expression, and eukaryotes share a major conserved mRNA decay pathway. In this major pathway, the two rate-determining steps in mRNA degradation are the initial gradual removal of the poly(A) tail, followed by removal of the cap structure. Removal of the cap structure is carried out by the decapping enzyme, containing the Dcp2 catalytic subunit. Although the mechanism and regulation of mRNA decay is well understood, the consequences of defects in mRNA degradation are less clear. Dcp2 has been reported as either essential or nonessential. Here, we clarify that Dcp2 is not absolutely required for spore germination and extremely slow growth, but in practical terms it is impossible to continuously culture dcp2∆ under laboratory conditions without suppressors arising. We show that null mutations in at least three different genes are each sufficient to restore growth to a dcp2∆, of which kap123∆ and tl(gag)g∆ appear the most specific. We show that kap123∆ and tl(gag)g∆ suppress dcp2 by mechanisms that are different from each other and from previously isolated dcp2 suppressors. The suppression mechanism for tL(GAG)G is determined by the unique GAG anticodon of this tRNA, and thus likely by translation of some CUC or CUU codons. Unlike previously reported suppressors of decapping defects, these suppressors do not detectably restore decapping or mRNA decay to normal rates, but instead allow survival while only modestly affecting RNA homeostasis. These results provide important new insight into the importance of decapping, resolve previously conflicting publications about the essentiality of DCP2, provide the first phenotype for a tl(gag)g mutant, and show that multiple distinct mechanisms can bypass Dcp2 requirement.
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Affiliation(s)
- Minseon Kim
- Microbiology and Molecular Genetics Department, University of Texas Health Science Center at Houston, Houston, Texas 77030
| | - Ambro van Hoof
- Microbiology and Molecular Genetics Department, University of Texas Health Science Center at Houston, Houston, Texas 77030
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17
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Guha S, Bhaumik SR. Viral regulation of mRNA export with potentials for targeted therapy. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2020; 1864:194655. [PMID: 33246183 DOI: 10.1016/j.bbagrm.2020.194655] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 07/04/2020] [Revised: 10/15/2020] [Accepted: 11/05/2020] [Indexed: 12/12/2022]
Abstract
Eukaryotic gene expression begins with transcription in the nucleus to synthesize mRNA (messenger RNA), which is subsequently exported to the cytoplasm for translation to protein. Like transcription and translation, mRNA export is an important regulatory step of eukaryotic gene expression. Various factors are involved in regulating mRNA export, and thus gene expression. Intriguingly, some of these factors interact with viral proteins, and such interactions interfere with mRNA export of the host cell, favoring viral RNA export. Hence, viruses hijack host mRNA export machinery for export of their own RNAs from nucleus to cytoplasm for translation to proteins for viral life cycle, suppressing host mRNA export (and thus host gene expression and immune/antiviral response). Therefore, the molecules that can impair the interactions of these mRNA export factors with viral proteins could emerge as antiviral therapeutic agents to suppress viral RNA transport and enhance host mRNA export, thereby promoting host gene expression and immune response. Thus, there has been a number of studies to understand how virus hijacks mRNA export machinery in suppressing host gene expression and promoting its own RNA export to the cytoplasm for translation to proteins required for viral replication/assembly/life cycle towards developing targeted antiviral therapies, as concisely described here.
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Affiliation(s)
- Shalini Guha
- Department of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, IL 62901, USA
| | - Sukesh R Bhaumik
- Department of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, IL 62901, USA.
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18
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Emerging molecular functions and novel roles for the DEAD-box protein Dbp5/DDX19 in gene expression. Cell Mol Life Sci 2020; 78:2019-2030. [PMID: 33205304 DOI: 10.1007/s00018-020-03680-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2020] [Revised: 09/21/2020] [Accepted: 10/06/2020] [Indexed: 12/23/2022]
Abstract
The DEAD-box protein (DBP) Dbp5, a member of the superfamily II (SFII) helicases, has multiple reported roles in gene expression. First identified as an essential regulator of mRNA export in Saccharomyces cerevisiae, the enzyme now has reported functions in non-coding RNA export, translation, transcription, and DNA metabolism. Localization of the protein to various cellular compartments (nucleoplasm, nuclear envelope, and cytoplasm) highlights the ability of Dbp5 to modulate different stages of the RNA lifecycle. While Dbp5 has been well studied for > 20 years, several critical questions remain regarding the mechanistic principles that govern Dbp5 localization, substrate selection, and functions in gene expression. This review aims to take a holistic view of the proposed functions of Dbp5 and evaluate models that accommodate current published data.
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19
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Keegan SE, Hughes SC. Role of nuclear-cytoplasmic protein localization during Drosophila neuroblast development. Genome 2020; 64:75-85. [PMID: 32526151 DOI: 10.1139/gen-2020-0039] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Nuclear-cytoplasmic localization is an efficient way to regulate transcription factors and chromatin remodelers. Altering the location of existing protein pools also facilitates a more rapid response to changes in cell activity or extracellular signals. There are several examples of proteins that are regulated by nucleo-cytoplasmic shuttling, which are required for Drosophila neuroblast development. Disruption of the localization of homologs of these proteins has also been linked to several neurodegenerative disorders in humans. Drosophila has been used extensively to model the neurodegenerative disorders caused by aberrant nucleo-cytoplasmic localization. Here, we focus on the role of alternative nucleo-cytoplasmic protein localization in regulating proliferation and cell fate decisions in the Drosophila neuroblast and in neurodegenerative disorders. We also explore the analogous role of RNA binding proteins and mRNA localization in the context of regulation of nucleo-cytoplasmic localization during neural development and a role in neurodegenerative disorders.
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Affiliation(s)
- Sophie E Keegan
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Sarah C Hughes
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada.,Department of Medical Genetics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
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20
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Makio T, Wozniak RW. Passive diffusion through nuclear pore complexes regulates levels of the yeast SAGA and SLIK coactivator complexes. J Cell Sci 2020; 133:jcs237156. [PMID: 32051285 DOI: 10.1242/jcs.237156] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Accepted: 01/31/2020] [Indexed: 11/20/2022] Open
Abstract
Nuclear pore complexes (NPCs) control gene expression by regulating the bi-directional exchange of proteins and RNAs between nuclear and cytoplasmic compartments, including access of transcriptional regulators to the nucleoplasm. Here, we show that the yeast (Saccharomyces cerevisiae) nucleoporin Nup170, in addition to binding and silencing subtelomeric genes, supports transcription of genes regulated by the SAGA transcriptional activator complex. Specifically, we show that a lower amount of SAGA complex is bound to target genes in the absence of Nup170. Consistent with this observation, levels of the SAGA complex are decreased in cells lacking Nup170, while those of the SAGA-related SLIK complexes are increased. This change in the ratio of SAGA to SLIK complexes is due to increased nuclear activity of Pep4, a protease responsible for production of the SLIK complex. Further analyses of various nucleoporin mutants revealed that the increased nuclear entry of Pep4 observed in the nup170Δ mutant likely occurs as the consequence of an increase in the sieving limits of the NPC diffusion channel. On the basis of these results, we propose that changes in passive diffusion rates represent a mechanism for regulating SAGA- and SLIK complex-mediated transcriptional events.
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Affiliation(s)
- Tadashi Makio
- Department of Cell Biology, University of Alberta, Edmonton, AB, Canada, T6G 2H7
| | - Richard W Wozniak
- Department of Cell Biology, University of Alberta, Edmonton, AB, Canada, T6G 2H7
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21
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Rempel IL, Popken P, Ghavami A, Mishra A, Hapsari RA, Wolters AHG, Veldsink AC, Klaassens M, Meinema AC, Poolman B, Giepmans BNG, Onck PR, Steen A, Veenhoff LM. Flexible and Extended Linker Domains Support Efficient Targeting of Heh2 to the Inner Nuclear Membrane. Structure 2020; 28:185-195.e5. [PMID: 31806352 DOI: 10.1016/j.str.2019.11.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Revised: 08/09/2019] [Accepted: 11/08/2019] [Indexed: 10/25/2022]
Abstract
The nuclear pore complex (NPC) is embedded in the nuclear envelope and forms the main gateway to the nuclear interior including the inner nuclear membrane (INM). Two INM proteins in yeast are selectively imported. Their sorting signals consist of a nuclear localization signal, separated from the transmembrane domain by a long intrinsically disordered (ID) linker. We used computational models to predict the dynamic conformations of ID linkers and analyzed the INM targeting efficiency of proteins with linker regions with altered Stokes radii and decreased flexibilities. We find that flexibility, Stokes radius, and the frequency at which the linkers are at an extended end-to-end distance larger than 25 nm are good predictors for the targeting of the proteins. The data are consistent with a transport mechanism in which INM targeting of Heh2 is dependent on an ID linker that facilitates the crossing of the approximately 25-nm thick NPC scaffold.
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Affiliation(s)
- Irina L Rempel
- European Research Institute for the Biology of Ageing (ERIBA), University of Groningen, University Medical Center Groningen, Antonius Deusinglaan 1, Groningen 9713 AV, Netherlands
| | - Petra Popken
- European Research Institute for the Biology of Ageing (ERIBA), University of Groningen, University Medical Center Groningen, Antonius Deusinglaan 1, Groningen 9713 AV, Netherlands; Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, Groningen 9747 AG, The Netherlands; Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, Groningen 9747 AG, The Netherlands
| | - Ali Ghavami
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, Groningen 9747 AG, The Netherlands
| | - Ankur Mishra
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, Groningen 9747 AG, The Netherlands
| | - Rizqiya A Hapsari
- European Research Institute for the Biology of Ageing (ERIBA), University of Groningen, University Medical Center Groningen, Antonius Deusinglaan 1, Groningen 9713 AV, Netherlands
| | - Anouk H G Wolters
- Department of Biomedical Sciences of Cells and Systems, University of Groningen, University Medical Center Groningen, Antonius Deusinglaan 1, Groningen 9713 AV, Netherlands
| | - Annemiek C Veldsink
- European Research Institute for the Biology of Ageing (ERIBA), University of Groningen, University Medical Center Groningen, Antonius Deusinglaan 1, Groningen 9713 AV, Netherlands
| | - Marindy Klaassens
- European Research Institute for the Biology of Ageing (ERIBA), University of Groningen, University Medical Center Groningen, Antonius Deusinglaan 1, Groningen 9713 AV, Netherlands
| | - Anne C Meinema
- Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, Groningen 9747 AG, The Netherlands
| | - Bert Poolman
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, Groningen 9747 AG, The Netherlands; Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, Groningen 9747 AG, The Netherlands
| | - Ben N G Giepmans
- Department of Biomedical Sciences of Cells and Systems, University of Groningen, University Medical Center Groningen, Antonius Deusinglaan 1, Groningen 9713 AV, Netherlands
| | - Patrick R Onck
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, Groningen 9747 AG, The Netherlands.
| | - Anton Steen
- European Research Institute for the Biology of Ageing (ERIBA), University of Groningen, University Medical Center Groningen, Antonius Deusinglaan 1, Groningen 9713 AV, Netherlands.
| | - Liesbeth M Veenhoff
- European Research Institute for the Biology of Ageing (ERIBA), University of Groningen, University Medical Center Groningen, Antonius Deusinglaan 1, Groningen 9713 AV, Netherlands.
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22
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Blus BJ, Koh J, Krolak A, Seo HS, Coutavas E, Blobel G. Allosteric modulation of nucleoporin assemblies by intrinsically disordered regions. SCIENCE ADVANCES 2019; 5:eaax1836. [PMID: 31807700 PMCID: PMC6881172 DOI: 10.1126/sciadv.aax1836] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 09/25/2019] [Indexed: 05/12/2023]
Abstract
Intrinsically disordered regions (IDRs) of proteins are implicated in key macromolecular interactions. However, the molecular forces underlying IDR function within multicomponent assemblies remain elusive. By combining thermodynamic and structural data, we have discovered an allostery-based mechanism regulating the soluble core region of the nuclear pore complex (NPC) composed of nucleoporins Nup53, Nic96, and Nup157. We have identified distinct IDRs in Nup53 that are functionally coupled when binding to partner nucleoporins and karyopherins (Kaps) involved in NPC assembly and nucleocytoplasmic transport. We show that the Nup53·Kap121 complex forms an ensemble of structures that destabilize Nup53 hub interactions. Our study provides a molecular framework for understanding how disordered and folded domains communicate within macromolecular complexes.
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Affiliation(s)
- Bartlomiej Jan Blus
- Laboratory of Cell Biology, Howard Hughes Medical Institute, The Rockefeller University, New York, NY 10065, USA
- Corresponding author.
| | - Junseock Koh
- School of Biological Sciences, Seoul National University, Seoul, 08826, South Korea
| | - Aleksandra Krolak
- Laboratory of Cell Biology, Howard Hughes Medical Institute, The Rockefeller University, New York, NY 10065, USA
| | - Hyuk-Soo Seo
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA 02215, USA
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA
| | - Elias Coutavas
- Laboratory of Cell Biology, Howard Hughes Medical Institute, The Rockefeller University, New York, NY 10065, USA
| | - Günter Blobel
- Laboratory of Cell Biology, Howard Hughes Medical Institute, The Rockefeller University, New York, NY 10065, USA
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23
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Roy A, Narayan G. Oncogenic potential of nucleoporins in non-hematological cancers: recent update beyond chromosome translocation and gene fusion. J Cancer Res Clin Oncol 2019; 145:2901-2910. [DOI: 10.1007/s00432-019-03063-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Accepted: 10/18/2019] [Indexed: 12/13/2022]
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24
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Vallotton P, Rajoo S, Wojtynek M, Onischenko E, Kralt A, Derrer CP, Weis K. Mapping the native organization of the yeast nuclear pore complex using nuclear radial intensity measurements. Proc Natl Acad Sci U S A 2019; 116:14606-14613. [PMID: 31262825 PMCID: PMC6642398 DOI: 10.1073/pnas.1903764116] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Selective transport across the nuclear envelope (NE) is mediated by the nuclear pore complex (NPC), a massive ∼100-MDa assembly composed of multiple copies of ∼30 nuclear pore proteins (Nups). Recent advances have shed light on the composition and structure of NPCs, but approaches that could map their organization in live cells are still lacking. Here, we introduce an in vivo method to perform nuclear radial intensity measurements (NuRIM) using fluorescence microscopy to determine the average position of NE-localized proteins along the nucleocytoplasmic transport axis. We apply NuRIM to study the organization of the NPC and the mobile transport machinery in budding yeast. This reveals a unique snapshot of the intact yeast NPC and identifies distinct steady-state localizations for various NE-associated proteins and nuclear transport factors. We find that the NPC architecture is robust against compositional changes and could also confirm that in contrast to Chlamydomonas reinhardtii, the scaffold Y complex is arranged symmetrically in the yeast NPC. Furthermore, NuRIM was applied to probe the orientation of intrinsically disordered FG-repeat segments, providing insight into their roles in selective NPC permeability and structure.
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Affiliation(s)
- Pascal Vallotton
- Institute of Biochemistry, Department of Biology, Swiss Federal Institute of Technology Zürich (ETH Zürich), 8093 Zürich, Switzerland;
| | - Sasikumar Rajoo
- Institute of Biochemistry, Department of Biology, Swiss Federal Institute of Technology Zürich (ETH Zürich), 8093 Zürich, Switzerland
| | - Matthias Wojtynek
- Institute of Biochemistry, Department of Biology, Swiss Federal Institute of Technology Zürich (ETH Zürich), 8093 Zürich, Switzerland
- Department of Biochemistry, University of Zürich, 8057 Zürich, Switzerland
| | - Evgeny Onischenko
- Institute of Biochemistry, Department of Biology, Swiss Federal Institute of Technology Zürich (ETH Zürich), 8093 Zürich, Switzerland
| | - Annemarie Kralt
- Institute of Biochemistry, Department of Biology, Swiss Federal Institute of Technology Zürich (ETH Zürich), 8093 Zürich, Switzerland
| | - Carina Patrizia Derrer
- Institute of Biochemistry, Department of Biology, Swiss Federal Institute of Technology Zürich (ETH Zürich), 8093 Zürich, Switzerland
| | - Karsten Weis
- Institute of Biochemistry, Department of Biology, Swiss Federal Institute of Technology Zürich (ETH Zürich), 8093 Zürich, Switzerland;
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25
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Wendler P, Enenkel C. Nuclear Transport of Yeast Proteasomes. Front Mol Biosci 2019; 6:34. [PMID: 31157235 PMCID: PMC6532418 DOI: 10.3389/fmolb.2019.00034] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2019] [Accepted: 04/26/2019] [Indexed: 11/13/2022] Open
Abstract
Proteasomes are key proteases in regulating protein homeostasis. Their holo-enzymes are composed of 40 different subunits which are arranged in a proteolytic core (CP) flanked by one to two regulatory particles (RP). Proteasomal proteolysis is essential for the degradation of proteins which control time-sensitive processes like cell cycle progression and stress response. In dividing yeast and human cells, proteasomes are primarily nuclear suggesting that proteasomal proteolysis is mainly required in the nucleus during cell proliferation. In yeast, which have a closed mitosis, proteasomes are imported into the nucleus as immature precursors via the classical import pathway. During quiescence, the reversible absence of proliferation induced by nutrient depletion or growth factor deprivation, proteasomes move from the nucleus into the cytoplasm. In the cytoplasm of quiescent yeast, proteasomes are dissociated into CP and RP and stored in membrane-less cytoplasmic foci, named proteasome storage granules (PSGs). With the resumption of growth, PSGs clear and mature proteasomes are transported into the nucleus by Blm10, a conserved 240 kDa protein and proteasome-intrinsic import receptor. How proteasomes are exported from the nucleus into the cytoplasm is unknown.
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Affiliation(s)
- Petra Wendler
- Institut für Biochemie und Biologie, Universität Potsdam, Potsdam, Germany
| | - Cordula Enenkel
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada
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26
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Li S, Dong Z, Yang S, Feng J, Li Q. Chaperoning RPA during DNA metabolism. Curr Genet 2019; 65:857-864. [PMID: 30796471 DOI: 10.1007/s00294-019-00945-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 02/14/2019] [Accepted: 02/15/2019] [Indexed: 12/17/2022]
Abstract
Single-stranded DNA (ssDNA) is widely generated during DNA metabolisms including DNA replication, repair and recombination and is susceptible to digestion by nucleases and secondary structure formation. It is vital for DNA metabolism and genome stability that ssDNA is protected and stabilized, which are performed by the major ssDNA-binding protein, and replication protein A (RPA) in these processes. In addition, RPA-coated ssDNA also serves as a protein-protein-binding platform for coordinating multiple events during DNA metabolisms. However, little is known about whether and how the formation of RPA-ssDNA platform is regulated. Here we highlight our recent study of a novel RPA-binding protein, Regulator of Ty1 transposition 105 (Rtt105) in Saccharomyces cerevisiae, which regulates the RPA-ssDNA platform assembly at replication forks. We propose that Rtt105 functions as an "RPA chaperone" during DNA replication, likely also promoting the assembly of RPA-ssDNA platform in other processes in which RPA plays a critical role.
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Affiliation(s)
- Shuqi Li
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences and Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, 100871, China.,Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, 100871, China.,Laboratory of Host-Pathogen Biology, The Rockefeller University, 1230 York Avenue, New York, NY, 10065, USA
| | - Ziqi Dong
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences and Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, 100871, China
| | - Shuangshuang Yang
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences and Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, 100871, China
| | - Jianxun Feng
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences and Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, 100871, China
| | - Qing Li
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences and Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, 100871, China. .,Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, 100871, China.
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Distribution of Proteins at the Inner Nuclear Membrane Is Regulated by the Asi1 E3 Ligase in Saccharomyces cerevisiae. Genetics 2019; 211:1269-1282. [PMID: 30709848 PMCID: PMC6456303 DOI: 10.1534/genetics.119.301911] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2018] [Accepted: 01/30/2019] [Indexed: 12/11/2022] Open
Abstract
Inner nuclear membrane (INM) protein composition regulates nuclear function, affecting processes such as gene expression, chromosome organization, nuclear shape, and stability. Mechanisms that drive changes in the INM proteome are poorly understood, in part because it is difficult to definitively assay INM composition rigorously and systematically. Using a split-GFP complementation system to detect INM access, we examined the distribution of all C-terminally tagged Saccharomyces cerevisiae membrane proteins in wild-type cells and in mutants affecting protein quality control pathways, such as INM-associated degradation (INMAD), ER-associated degradation, and vacuolar proteolysis. Deletion of the E3 ligase Asi1 had the most specific effect on the INM compared to mutants in vacuolar or ER-associated degradation pathways, consistent with a role for Asi1 in the INMAD pathway. Our data suggest that Asi1 not only removes mistargeted proteins at the INM, but also controls the levels and distribution of native INM components, such as the membrane nucleoporin Pom33. Interestingly, loss of Asi1 does not affect Pom33 protein levels but instead alters Pom33 distribution in the nuclear envelope through Pom33 ubiquitination, which drives INM redistribution. Taken together, our data demonstrate that the Asi1 E3 ligase has a novel function in INM protein regulation in addition to protein turnover.
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Rapoport A, Golovina EA, Gervais P, Dupont S, Beney L. Anhydrobiosis: Inside yeast cells. Biotechnol Adv 2019; 37:51-67. [DOI: 10.1016/j.biotechadv.2018.11.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 11/01/2018] [Accepted: 11/13/2018] [Indexed: 12/21/2022]
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29
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Wang Y, Zhong S, Schofield CJ, Ratcliffe PJ, Lu X. Nuclear entry and export of FIH are mediated by HIF1α and exportin1, respectively. J Cell Sci 2018; 131:jcs219782. [PMID: 30333145 PMCID: PMC6250434 DOI: 10.1242/jcs.219782] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 10/05/2018] [Indexed: 12/18/2022] Open
Abstract
Hypoxia plays a crucial role at cellular and physiological levels in all animals. The responses to chronic hypoxia are, at least substantially, orchestrated by activation of the hypoxia inducible transcription factors (HIFs), whose stability and subsequent transcriptional activation are regulated by HIF hydroxylases. Factor inhibiting HIF (FIH), initially isolated as a HIFα interacting protein following a yeast two-hybrid screen, is an asparaginyl hydroxylase that negatively regulates transcriptional activation by HIF. This study aimed to define the mechanisms that govern transitions of FIH between the nucleus and cytoplasm. We report that FIH accumulates in the nucleus within a short time window during hypoxia treatment. We provide evidence, based on the application of genetic interventions and small molecule inhibition of the HIF hydroxylases, that the nuclear localization of FIH is governed by two opposing processes: nuclear entry by 'coupling' with HIF1α for importin β1-mediated nuclear import and active export via a Leptomycin B-sensitive exportin1-dependent pathway.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Yihua Wang
- Ludwig Institute for Cancer Research Ltd., Nuffield Department of Clinical Medicine, University of Oxford, Old Road Campus, Roosevelt Drive, Oxford OX3 7DQ, United Kingdom
- Biological Sciences, Faculty of Environmental and Life Sciences, University of Southampton, Southampton SO17 1BJ, United Kingdom
| | - Shan Zhong
- Ludwig Institute for Cancer Research Ltd., Nuffield Department of Clinical Medicine, University of Oxford, Old Road Campus, Roosevelt Drive, Oxford OX3 7DQ, United Kingdom
| | - Christopher J Schofield
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA, United Kingdom
| | - Peter J Ratcliffe
- Ludwig Institute for Cancer Research Ltd., Nuffield Department of Clinical Medicine, University of Oxford, Old Road Campus, Roosevelt Drive, Oxford OX3 7DQ, United Kingdom
- Target Discovery Institute, NDM Research Building, University of Oxford, Old Road Campus, Roosevelt Drive, Oxford OX3 7FZ, United Kingdom
| | - Xin Lu
- Ludwig Institute for Cancer Research Ltd., Nuffield Department of Clinical Medicine, University of Oxford, Old Road Campus, Roosevelt Drive, Oxford OX3 7DQ, United Kingdom
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30
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Scapin G, Potter CS, Carragher B. Cryo-EM for Small Molecules Discovery, Design, Understanding, and Application. Cell Chem Biol 2018; 25:1318-1325. [PMID: 30100349 DOI: 10.1016/j.chembiol.2018.07.006] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Revised: 05/11/2018] [Accepted: 07/05/2018] [Indexed: 12/13/2022]
Abstract
We present a perspective of our view of the application of cryoelectron microscopy (cryo-EM) to structure-based drug design (SBDD). We discuss the basic needs and requirements for SBDD, the current state of cryo-EM, and the challenges that need to be overcome for this technique to reach its full potential in facilitating the process of drug discovery.
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Affiliation(s)
- Giovanna Scapin
- Department of Biochemical Engineering & Structure, Merck & Co., Inc., 2000 Galloping Hill Rd., Kenilworth, NJ 07033, USA
| | - Clinton S Potter
- Simons Electron Microscopy Center, National Resource for Automated Molecular Microscopy, New York Structural Biology Center, 89 Convent Avenue, New York NY 10027, USA; NanoImaging Services, 4940 Carroll Canyon Road, Suite 115, San Diego, CA 92121, USA
| | - Bridget Carragher
- Simons Electron Microscopy Center, National Resource for Automated Molecular Microscopy, New York Structural Biology Center, 89 Convent Avenue, New York NY 10027, USA; NanoImaging Services, 4940 Carroll Canyon Road, Suite 115, San Diego, CA 92121, USA.
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31
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Bao XX, Spanos C, Kojidani T, Lynch EM, Rappsilber J, Hiraoka Y, Haraguchi T, Sawin KE. Exportin Crm1 is repurposed as a docking protein to generate microtubule organizing centers at the nuclear pore. eLife 2018; 7:e33465. [PMID: 29809148 PMCID: PMC6008054 DOI: 10.7554/elife.33465] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Accepted: 05/21/2018] [Indexed: 01/04/2023] Open
Abstract
Non-centrosomal microtubule organizing centers (MTOCs) are important for microtubule organization in many cell types. In fission yeast Schizosaccharomyces pombe, the protein Mto1, together with partner protein Mto2 (Mto1/2 complex), recruits the γ-tubulin complex to multiple non-centrosomal MTOCs, including the nuclear envelope (NE). Here, we develop a comparative-interactome mass spectrometry approach to determine how Mto1 localizes to the NE. Surprisingly, we find that Mto1, a constitutively cytoplasmic protein, docks at nuclear pore complexes (NPCs), via interaction with exportin Crm1 and cytoplasmic FG-nucleoporin Nup146. Although Mto1 is not a nuclear export cargo, it binds Crm1 via a nuclear export signal-like sequence, and docking requires both Ran in the GTP-bound state and Nup146 FG repeats. In addition to determining the mechanism of MTOC formation at the NE, our results reveal a novel role for Crm1 and the nuclear export machinery in the stable docking of a cytoplasmic protein complex at NPCs.
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Affiliation(s)
- Xun X Bao
- Wellcome Centre for Cell Biology, School of Biological SciencesUniversity of EdinburghEdinburghUnited Kingdom
| | - Christos Spanos
- Wellcome Centre for Cell Biology, School of Biological SciencesUniversity of EdinburghEdinburghUnited Kingdom
| | - Tomoko Kojidani
- Advanced ICT Research Institute KobeNational Institute of Information and Communications TechnologyKobeJapan
- Department of Chemical and Biological Sciences, Faculty of ScienceJapan Women’s UniversityTokyoJapan
| | - Eric M Lynch
- Wellcome Centre for Cell Biology, School of Biological SciencesUniversity of EdinburghEdinburghUnited Kingdom
| | - Juri Rappsilber
- Wellcome Centre for Cell Biology, School of Biological SciencesUniversity of EdinburghEdinburghUnited Kingdom
- Department of BioanalyticsInstitute of Biotechnology, Technische Universität BerlinBerlinGermany
| | - Yasushi Hiraoka
- Advanced ICT Research Institute KobeNational Institute of Information and Communications TechnologyKobeJapan
- Graduate School of Frontier BiosciencesOsaka UniversitySuitaJapan
| | - Tokuko Haraguchi
- Advanced ICT Research Institute KobeNational Institute of Information and Communications TechnologyKobeJapan
- Graduate School of Frontier BiosciencesOsaka UniversitySuitaJapan
| | - Kenneth E Sawin
- Wellcome Centre for Cell Biology, School of Biological SciencesUniversity of EdinburghEdinburghUnited Kingdom
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32
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Rowley PA, Patterson K, Sandmeyer SB, Sawyer SL. Control of yeast retrotransposons mediated through nucleoporin evolution. PLoS Genet 2018; 14:e1007325. [PMID: 29694349 PMCID: PMC5918913 DOI: 10.1371/journal.pgen.1007325] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Accepted: 03/21/2018] [Indexed: 02/07/2023] Open
Abstract
Yeasts serve as hosts to several types of genetic parasites. Few studies have addressed the evolutionary trajectory of yeast genes that control the stable co-existence of these parasites with their host cell. In Saccharomyces yeasts, the retrovirus-like Ty retrotransposons must access the nucleus. We show that several genes encoding components of the yeast nuclear pore complex have experienced natural selection for substitutions that change the encoded protein sequence. By replacing these S. cerevisiae genes with orthologs from other Saccharomyces species, we discovered that natural sequence changes have affected the mobility of Ty retrotransposons. Specifically, changing the genetic sequence of NUP84 or NUP82 to match that of other Saccharomyces species alters the mobility of S. cerevisiae Ty1 and Ty3. Importantly, all tested housekeeping functions of NUP84 and NUP82 remained equivalent across species. Signatures of natural selection, resulting in altered interactions with viruses and parasitic genetic elements, are common in host defense proteins. Yet, few instances have been documented in essential housekeeping proteins. The nuclear pore complex is the gatekeeper of the nucleus. This study shows how the evolution of this large, ubiquitous eukaryotic complex can alter the replication of a molecular parasite, but concurrently maintain essential host functionalities regarding nucleocytoplasmic trafficking.
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Affiliation(s)
- Paul A. Rowley
- BioFrontiers Institute, Department of Molecular Cellular and Developmental Biology, University of Colorado Boulder, Boulder, CO, United States of America
- Department of Biological Sciences, University of Idaho, Moscow, ID, United States of America
| | - Kurt Patterson
- Department of Biological Chemistry, School of Medicine, University of California, Irvine, Irvine, CA, United States of America
| | - Suzanne B. Sandmeyer
- Department of Biological Chemistry, School of Medicine, University of California, Irvine, Irvine, CA, United States of America
| | - Sara L. Sawyer
- BioFrontiers Institute, Department of Molecular Cellular and Developmental Biology, University of Colorado Boulder, Boulder, CO, United States of America
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33
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Yakobov N, Debard S, Fischer F, Senger B, Becker HD. Cytosolic aminoacyl-tRNA synthetases: Unanticipated relocations for unexpected functions. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2017; 1861:387-400. [PMID: 29155070 DOI: 10.1016/j.bbagrm.2017.11.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 11/13/2017] [Accepted: 11/14/2017] [Indexed: 12/13/2022]
Abstract
Prokaryotic and eukaryotic cytosolic aminoacyl-tRNA synthetases (aaRSs) are essentially known for their conventional function of generating the full set of aminoacyl-tRNA species that are needed to incorporate each organism's repertoire of genetically-encoded amino acids during ribosomal translation of messenger RNAs. However, bacterial and eukaryotic cytosolic aaRSs have been shown to exhibit other essential nonconventional functions. Here we review all the subcellular compartments that prokaryotic and eukaryotic cytosolic aaRSs can reach to exert either a conventional or nontranslational role. We describe the physiological and stress conditions, the mechanisms and the signaling pathways that trigger their relocation and the new functions associated with these relocating cytosolic aaRS. Finally, given that these relocating pools of cytosolic aaRSs participate to a wide range of cellular pathways beyond translation, but equally important for cellular homeostasis, we mention some of the pathologies and diseases associated with the dis-regulation or malfunctioning of these nontranslational functions.
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Affiliation(s)
- Nathaniel Yakobov
- Génétique Moléculaire, Génomique, Microbiologie, UMR 7156, CNRS, Université de Strasbourg, Institut de Botanique, 28 rue Goethe, 67083 Strasbourg Cedex, France
| | - Sylvain Debard
- Génétique Moléculaire, Génomique, Microbiologie, UMR 7156, CNRS, Université de Strasbourg, Institut de Botanique, 28 rue Goethe, 67083 Strasbourg Cedex, France
| | - Frédéric Fischer
- Génétique Moléculaire, Génomique, Microbiologie, UMR 7156, CNRS, Université de Strasbourg, Institut de Botanique, 28 rue Goethe, 67083 Strasbourg Cedex, France
| | - Bruno Senger
- Génétique Moléculaire, Génomique, Microbiologie, UMR 7156, CNRS, Université de Strasbourg, Institut de Botanique, 28 rue Goethe, 67083 Strasbourg Cedex, France
| | - Hubert Dominique Becker
- Génétique Moléculaire, Génomique, Microbiologie, UMR 7156, CNRS, Université de Strasbourg, Institut de Botanique, 28 rue Goethe, 67083 Strasbourg Cedex, France.
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34
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Lapetina DL, Ptak C, Roesner UK, Wozniak RW. Yeast silencing factor Sir4 and a subset of nucleoporins form a complex distinct from nuclear pore complexes. J Cell Biol 2017; 216:3145-3159. [PMID: 28883038 PMCID: PMC5626528 DOI: 10.1083/jcb.201609049] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2016] [Revised: 05/26/2017] [Accepted: 07/31/2017] [Indexed: 11/22/2022] Open
Abstract
Lapetina et al. identify a protein interaction network involved in the association of chromatin with the nuclear envelope. This network includes a telomere tether, a silencing factor, a SUMO E3 ligase, and an array of nucleoporins that together form a complex distinct from nuclear pore complexes. Interactions occurring at the nuclear envelope (NE)–chromatin interface influence both NE structure and chromatin organization. Insights into the functions of NE–chromatin interactions have come from the study of yeast subtelomeric chromatin and its association with the NE, including the identification of various proteins necessary for tethering subtelomeric chromatin to the NE and the silencing of resident genes. Here we show that four of these proteins—the silencing factor Sir4, NE-associated Esc1, the SUMO E3 ligase Siz2, and the nuclear pore complex (NPC) protein Nup170—physically and functionally interact with one another and a subset of NPC components (nucleoporins or Nups). Importantly, this group of Nups is largely restricted to members of the inner and outer NPC rings, but it lacks numerous others including cytoplasmically and nucleoplasmically positioned Nups. We propose that this Sir4-associated Nup complex is distinct from holo-NPCs and that it plays a role in subtelomeric chromatin organization and NE tethering.
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Affiliation(s)
- Diego L Lapetina
- Department of Cell Biology, University of Alberta, Edmonton, Alberta, Canada
| | - Christopher Ptak
- Department of Cell Biology, University of Alberta, Edmonton, Alberta, Canada
| | - Ulyss K Roesner
- Department of Cell Biology, University of Alberta, Edmonton, Alberta, Canada
| | - Richard W Wozniak
- Department of Cell Biology, University of Alberta, Edmonton, Alberta, Canada
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35
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Valsecchi I, Sarikaya-Bayram Ö, Wong Sak Hoi J, Muszkieta L, Gibbons J, Prevost MC, Mallet A, Krijnse-Locker J, Ibrahim-Granet O, Mouyna I, Carr P, Bromley M, Aimanianda V, Yu JH, Rokas A, Braus GH, Saveanu C, Bayram Ö, Latgé JP. MybA, a transcription factor involved in conidiation and conidial viability of the human pathogenAspergillus fumigatus. Mol Microbiol 2017; 105:880-900. [DOI: 10.1111/mmi.13744] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/04/2017] [Indexed: 11/28/2022]
Affiliation(s)
| | | | | | | | - John Gibbons
- Department of Biological Sciences; Vanderbilt University; Nashville TN 37235 USA
| | | | - Adeline Mallet
- Plate-Forme de Microscopie Ultrastructurale; Institut Pasteur; Paris 75015 France
| | | | | | | | - Paul Carr
- Manchester Fungal Infection Group; Institute of Inflammation and Repair, University of Manchester; Manchester UK
| | - Michael Bromley
- Manchester Fungal Infection Group; Institute of Inflammation and Repair, University of Manchester; Manchester UK
| | | | - Jae-Hyuk Yu
- Department of Bacteriology and Genetics; University of Wisconsin; Madison WI 53706 USA
| | - Antonis Rokas
- Department of Biological Sciences; Vanderbilt University; Nashville TN 37235 USA
| | - Gerhard H Braus
- Department of Molecular Microbiology and Genetics; Georg August University; Göttingen 37077 Germany
| | - Cosmin Saveanu
- Unité de Génétique des Interactions Macromoléculaires; CNRS UMR3525, Institut Pasteur; Paris France
| | - Özgür Bayram
- Department of Biology; Maynooth University; Maynooth Co. Kildare Ireland
- Department of Molecular Microbiology and Genetics; Georg August University; Göttingen 37077 Germany
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36
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Functional implication of the common evolutionary origin of nuclear pore complex and endomembrane management systems. Semin Cell Dev Biol 2017; 68:10-17. [PMID: 28473267 DOI: 10.1016/j.semcdb.2017.04.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Accepted: 04/26/2017] [Indexed: 11/24/2022]
Abstract
Nuclear pore complexes (NPCs) are the sole gateway between the cytoplasm and the nucleus serving both as stringent permeability barrier and active transporters between the two compartments of eukaryotic cells. Complete mechanistic understanding of how these two functions are implemented within one and the same transport machine has not been attained to date. Based on several lines of structural evidence, a hypothesis was proposed postulating that NPCs shares common evolutionary origin with other intracellular systems responsible for active management of endomembranes. In this review we attempt to summarize the evidence supporting this hypothesis. The structural data obtained so far is evaluated and supplemented with the analysis of the functional evidence. Based on this analysis, a model is proposed which integrates the knowledge from the field of NPC function with that obtained from other endomembrane management systems in an attempt to shed new light on the mechanism of the NPC active transport.
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37
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The Nucleoporin Nup2 Contains a Meiotic-Autonomous Region that Promotes the Dynamic Chromosome Events of Meiosis. Genetics 2017; 206:1319-1337. [PMID: 28455351 DOI: 10.1534/genetics.116.194555] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Accepted: 04/17/2017] [Indexed: 11/18/2022] Open
Abstract
Meiosis is a specialized cellular program required to create haploid gametes from diploid parent cells. Homologous chromosomes pair, synapse, and recombine in a dynamic environment that accommodates gross chromosome reorganization and significant chromosome motion, which are critical for normal chromosome segregation. In Saccharomyces cerevisiae, Ndj1 is a meiotic telomere-associated protein required for physically attaching telomeres to proteins embedded in the nuclear envelope. In this study, we identified additional proteins that act at the nuclear periphery from meiotic cell extracts, including Nup2, a nonessential nucleoporin with a known role in tethering interstitial chromosomal loci to the nuclear pore complex. We found that deleting NUP2 affects meiotic progression and spore viability, and gives increased levels of recombination intermediates and products. We identified a previously uncharacterized 125 aa region of Nup2 that is necessary and sufficient for its meiotic function, thus behaving as a meiotic autonomous region (MAR). Nup2-MAR forms distinct foci on spread meiotic chromosomes, with a subset overlapping with Ndj1 foci. Localization of Nup2-MAR to meiotic chromosomes does not require Ndj1, nor does Ndj1 localization require Nup2, suggesting these proteins function in different pathways, and their interaction is weak or indirect. Instead, several severe synthetic phenotypes are associated with the nup2Δ ndj1Δ double mutant, including delayed turnover of recombination joint molecules, and a failure to undergo nuclear divisions without also arresting the meiotic program. These data suggest Nup2 and Ndj1 support partially overlapping functions that promote two different levels of meiotic chromosome organization necessary to withstand a dynamic stage of the eukaryotic life cycle.
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38
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Earnest TM, Watanabe R, Stone JE, Mahamid J, Baumeister W, Villa E, Luthey-Schulten Z. Challenges of Integrating Stochastic Dynamics and Cryo-Electron Tomograms in Whole-Cell Simulations. J Phys Chem B 2017; 121:3871-3881. [PMID: 28291359 DOI: 10.1021/acs.jpcb.7b00672] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Cryo-electron tomography (cryo-ET) has rapidly emerged as a powerful tool to investigate the internal, three-dimensional spatial organization of the cell. In parallel, the GPU-based technology to perform spatially resolved stochastic simulations of whole cells has arisen, allowing the simulation of complex biochemical networks over cell cycle time scales using data taken from -omics, single molecule experiments, and in vitro kinetics. By using real cell geometry derived from cryo-ET data, we have the opportunity to imbue these highly detailed structural data-frozen in time-with realistic biochemical dynamics and investigate how cell structure affects the behavior of the embedded chemical reaction network. Here we present two examples to illustrate the challenges and techniques involved in integrating structural data into stochastic simulations. First, a tomographic reconstruction of Saccharomyces cerevisiae is used to construct the geometry of an entire cell through which a simple stochastic model of an inducible genetic switch is studied. Second, a tomogram of the nuclear periphery in a HeLa cell is converted directly to the simulation geometry through which we study the effects of cellular substructure on the stochastic dynamics of gene repression. These simple chemical models allow us to illustrate how to build whole-cell simulations using cryo-ET derived geometry and the challenges involved in such a process.
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Affiliation(s)
- Tyler M Earnest
- National Center for Supercomputing Applications, University of Illinois at Urbana-Champaign , Urbana, Illinois, United States.,Department of Chemistry, University of Illinois at Urbana-Champaign , Urbana, Illinois, United States
| | - Reika Watanabe
- Department of Chemistry and Biochemistry, University of California , San Diego, California, United States
| | - John E Stone
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign , Urbana, Illinois, United States
| | - Julia Mahamid
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry , Munich, Germany
| | - Wolfgang Baumeister
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry , Munich, Germany
| | - Elizabeth Villa
- Department of Chemistry and Biochemistry, University of California , San Diego, California, United States
| | - Zaida Luthey-Schulten
- Department of Chemistry, University of Illinois at Urbana-Champaign , Urbana, Illinois, United States.,Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign , Urbana, Illinois, United States
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39
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Björk P, Wieslander L. Integration of mRNP formation and export. Cell Mol Life Sci 2017; 74:2875-2897. [PMID: 28314893 PMCID: PMC5501912 DOI: 10.1007/s00018-017-2503-3] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Revised: 03/06/2017] [Accepted: 03/07/2017] [Indexed: 12/13/2022]
Abstract
Expression of protein-coding genes in eukaryotes relies on the coordinated action of many sophisticated molecular machineries. Transcription produces precursor mRNAs (pre-mRNAs) and the active gene provides an environment in which the pre-mRNAs are processed, folded, and assembled into RNA–protein (RNP) complexes. The dynamic pre-mRNPs incorporate the growing transcript, proteins, and the processing machineries, as well as the specific protein marks left after processing that are essential for export and the cytoplasmic fate of the mRNPs. After release from the gene, the mRNPs move by diffusion within the interchromatin compartment, making up pools of mRNPs. Here, splicing and polyadenylation can be completed and the mRNPs recruit the major export receptor NXF1. Export competent mRNPs interact with the nuclear pore complex, leading to export, concomitant with compositional and conformational changes of the mRNPs. We summarize the integrated nuclear processes involved in the formation and export of mRNPs.
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Affiliation(s)
- Petra Björk
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 106 91 Stockholm, Sweden
| | - Lars Wieslander
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 106 91 Stockholm, Sweden
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40
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Abstract
Cell growth is a complex phenotype widely used in systems biology to gauge the impact of genetic and environmental perturbations. Due to the magnitude of genome-wide studies, resolution is often sacrificed in favor of throughput, creating a demand for scalable, time-resolved, quantitative methods of growth assessment. We present ODELAY (One-cell Doubling Evaluation by Living Arrays of Yeast), an automated and scalable growth analysis platform. High measurement density and single-cell resolution provide a powerful tool for large-scale multiparameter growth analysis based on the modeling of microcolony expansion on solid media. Pioneered in yeast but applicable to other colony forming organisms, ODELAY extracts the three key growth parameters (lag time, doubling time, and carrying capacity) that define microcolony expansion from single cells, simultaneously permitting the assessment of population heterogeneity. The utility of ODELAY is illustrated using yeast mutants, revealing a spectrum of phenotypes arising from single and combinatorial growth parameter perturbations.
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Oliveira LN, Casaletti L, Báo SN, Borges CL, de Sousa Lima P, de Almeida Soares CM. Characterizing the nuclear proteome of Paracoccidioides spp. Fungal Biol 2016; 120:1209-24. [PMID: 27647238 DOI: 10.1016/j.funbio.2016.07.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Revised: 07/05/2016] [Accepted: 07/07/2016] [Indexed: 10/21/2022]
Abstract
Paracoccidioidomycosis is an endemic disease in Latin America, caused by thermo dimorphic fungi of the genus Paracoccidioides. Although previous proteome analyses of Paracoccidioides spp. have been carried out, the nuclear subproteome of this pathogen has not been described. In this way, we aimed to characterize the nuclear proteome of Paracoccidioides species, in the yeast form. For that, yeast cells were disrupted and submitted to cell fractionation. The purity of the nuclear fraction was confirmed by fluorescence and electron microscopy. Liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) allowed the identification of 867 proteins. In order to support our enrichment method for nuclear proteins, bioinformatics analysis were applied that allowed the identification of 281 proteins with nuclear localization. The analysis revealed proteins related to DNA maintenance, gene expression, synthesis and processing of messenger and ribosomal RNAs, likewise proteins of nuclear-cytoplasmic traffic. It was also possible to detect some proteins that are poorly expressed, like transcription factors involved in important roles such as resistance to abiotic stress, sporulation, cellular growth and DNA and chromatin maintenance. This is the first descriptive nuclear proteome of Paracoccidioides spp. that can be useful as an important platform base for fungi-specific nuclear processes.
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Affiliation(s)
- Lucas Nojosa Oliveira
- Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, ICB II, Campus II, Universidade Federal de Goiás, Goiânia, Goiás, 74690-900, Brazil
| | - Luciana Casaletti
- Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, ICB II, Campus II, Universidade Federal de Goiás, Goiânia, Goiás, 74690-900, Brazil; Escola de Engenharia, Pontifícia Universidade Católica de Goiás, Goiânia, Goiás, 74605-010, Brazil
| | - Sônia Nair Báo
- Laboratório de Microscopia, Departamento de Biologia Celular, Instituto de Ciências Biológicas, Universidade de Brasília, Brasília, Distrito Federal, 70910-900, Brazil
| | - Clayton Luiz Borges
- Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, ICB II, Campus II, Universidade Federal de Goiás, Goiânia, Goiás, 74690-900, Brazil
| | - Patrícia de Sousa Lima
- Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, ICB II, Campus II, Universidade Federal de Goiás, Goiânia, Goiás, 74690-900, Brazil
| | - Célia Maria de Almeida Soares
- Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, ICB II, Campus II, Universidade Federal de Goiás, Goiânia, Goiás, 74690-900, Brazil.
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Moussavi-Baygi R, Mofrad MRK. Rapid Brownian Motion Primes Ultrafast Reconstruction of Intrinsically Disordered Phe-Gly Repeats Inside the Nuclear Pore Complex. Sci Rep 2016; 6:29991. [PMID: 27470900 PMCID: PMC4965864 DOI: 10.1038/srep29991] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Accepted: 06/24/2016] [Indexed: 11/23/2022] Open
Abstract
Conformational behavior of intrinsically disordered proteins, such as Phe-Gly repeat domains, alters drastically when they are confined in, and tethered to, nan channels. This has challenged our understanding of how they serve to selectively facilitate translocation of nuclear transport receptor (NTR)-bearing macromolecules. Heterogeneous FG-repeats, tethered to the NPC interior, nonuniformly fill the channel in a diameter-dependent manner and adopt a rapid Brownian motion, thereby forming a porous and highly dynamic polymeric meshwork that percolates in radial and axial directions and features two distinguishable zones: a dense hydrophobic rod-like zone located in the center, and a peripheral low-density shell-like zone. The FG-meshwork is locally disrupted upon interacting with NTR-bearing macromolecules, but immediately reconstructs itself between 0.44 μs and 7.0 μs, depending on cargo size and shape. This confers a perpetually-sealed state to the NPC, and is solely due to rapid Brownian motion of FG-repeats, not FG-repeat hydrophobic bonds. Elongated-shaped macromolecules, both in the presence and absence of NTRs, penetrate more readily into the FG-meshwork compared to their globular counterparts of identical volume and surface chemistry, highlighting the importance of the shape effects in nucleocytoplasmic transport. These results can help our understanding of geometrical effects in, and the design of, intelligent and responsive biopolymer-based materials in nanofiltration and artificial nanopores.
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Affiliation(s)
- R. Moussavi-Baygi
- Molecular Cell Biomechanics Laboratory, Departments of Bioengineering and Mechanical Engineering, University of California, Berkeley, CA 94720, USA
| | - M. R. K. Mofrad
- Molecular Cell Biomechanics Laboratory, Departments of Bioengineering and Mechanical Engineering, University of California, Berkeley, CA 94720, USA
- Molecular Biophysics and Integrative Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
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Saroufim MA, Bensidoun P, Raymond P, Rahman S, Krause MR, Oeffinger M, Zenklusen D. The nuclear basket mediates perinuclear mRNA scanning in budding yeast. J Cell Biol 2016; 211:1131-40. [PMID: 26694838 PMCID: PMC4687876 DOI: 10.1083/jcb.201503070] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Single-molecule resolution particle tracking reveals that mRNAs in S. cerevisiae scan the nuclear periphery before being exported to the cytoplasm and that this process is mediated by both components of the nuclear basket and the mRNP. After synthesis and transit through the nucleus, messenger RNAs (mRNAs) are exported to the cytoplasm through the nuclear pore complex (NPC). At the NPC, messenger ribonucleoproteins (mRNPs) first encounter the nuclear basket where mRNP rearrangements are thought to allow access to the transport channel. Here, we use single mRNA resolution live cell microscopy and subdiffraction particle tracking to follow individual mRNAs on their path toward the cytoplasm. We show that when reaching the nuclear periphery, RNAs are not immediately exported but scan along the nuclear periphery, likely to find a nuclear pore allowing export. Deletion or mutation of the nuclear basket proteins MLP1/2 or the mRNA binding protein Nab2 changes the scanning behavior of mRNPs at the nuclear periphery, shortens residency time at nuclear pores, and results in frequent release of mRNAs back into the nucleoplasm. These observations suggest a role for the nuclear basket in providing an interaction platform that keeps RNAs at the periphery, possibly to allow mRNP rearrangements before export.
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Affiliation(s)
- Mark-Albert Saroufim
- Departement de Biochimie et Medecine Moleculaire, Faculte de Medecine, Universite de Montreal, H3T 1J4 Montreal, Quebec, Canada
| | - Pierre Bensidoun
- Departement de Biochimie et Medecine Moleculaire, Faculte de Medecine, Universite de Montreal, H3T 1J4 Montreal, Quebec, Canada Institut de Recherches Cliniques de Montreal, H2W 1R7 Montreal, Quebec, Canada
| | - Pascal Raymond
- Departement de Biochimie et Medecine Moleculaire, Faculte de Medecine, Universite de Montreal, H3T 1J4 Montreal, Quebec, Canada
| | - Samir Rahman
- Departement de Biochimie et Medecine Moleculaire, Faculte de Medecine, Universite de Montreal, H3T 1J4 Montreal, Quebec, Canada
| | - Matthew R Krause
- Montreal Neurological Institute, McGill University, H3A 2B4 Montreal, Quebec, Canada
| | - Marlene Oeffinger
- Departement de Biochimie et Medecine Moleculaire, Faculte de Medecine, Universite de Montreal, H3T 1J4 Montreal, Quebec, Canada Institut de Recherches Cliniques de Montreal, H2W 1R7 Montreal, Quebec, Canada Faculty of Medicine, Division of Experimental Medicine, McGill University, H3A 2B4 Montreal, Quebec, Canada
| | - Daniel Zenklusen
- Departement de Biochimie et Medecine Moleculaire, Faculte de Medecine, Universite de Montreal, H3T 1J4 Montreal, Quebec, Canada
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Ptak C, Wozniak RW. Nucleoporins and chromatin metabolism. Curr Opin Cell Biol 2016; 40:153-160. [PMID: 27085162 DOI: 10.1016/j.ceb.2016.03.024] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2016] [Revised: 03/26/2016] [Accepted: 03/31/2016] [Indexed: 01/04/2023]
Abstract
Mounting evidence has implicated a group of proteins termed nucleoporins, or Nups, in various processes that regulate chromatin structure and function. Nups were first recognized as building blocks for nuclear pore complexes, but several members of this group of proteins also reside in the cytoplasm and within the nucleus. Moreover, many are dynamic and move between these various locations. Both at the nuclear envelope, as part of nuclear pore complexes, and within the nucleoplasm, Nups interact with protein complexes that function in gene transcription, chromatin remodeling, DNA repair, and DNA replication. Here, we review recent studies that provide further insight into the molecular details of these interactions and their role in regulating the activity of chromatin modifying factors.
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Affiliation(s)
- Christopher Ptak
- Department of Cell Biology, University of Alberta, Edmonton, Alberta, Canada T6G 2H7
| | - Richard W Wozniak
- Department of Cell Biology, University of Alberta, Edmonton, Alberta, Canada T6G 2H7.
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Meseroll RA, Cohen-Fix O. The Malleable Nature of the Budding Yeast Nuclear Envelope: Flares, Fusion, and Fenestrations. J Cell Physiol 2016; 231:2353-60. [PMID: 26909870 DOI: 10.1002/jcp.25355] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Accepted: 02/19/2016] [Indexed: 11/10/2022]
Abstract
In eukaryotes, the nuclear envelope (NE) physically separates nuclear components and activities from rest of the cell. The NE also provides rigidity to the nucleus and contributes to chromosome organization. At the same time, the NE is highly dynamic; it must change shape and rearrange its components during development and throughout the cell cycle, and its morphology can be altered in response to mutation and disease. Here we focus on the NE of budding yeast, Saccharomyces cerevisiae, which has several unique features: it remains intact throughout the cell cycle, expands symmetrically during interphase, elongates during mitosis and, expands asymmetrically during mitotic delay. Moreover, its NE is safely breached during mating and when large structures, such as nuclear pore complexes and the spindle pole body, are embedded into its double membrane. The budding yeast NE lacks lamins and yet the nucleus is capable of maintaining a spherical shape throughout interphase. Despite these eccentricities, studies of the budding yeast NE have uncovered interesting, and likely conserved, processes that contribute to NE dynamics. In particular, we discuss the processes that drive and enable NE expansion and the dramatic changes in the NE that lead to extensions and fenestrations. J. Cell. Physiol. 231: 2353-2360, 2016. Published 2016. This article is a U.S. Government work and is in the public domain in the USA.
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Affiliation(s)
- Rebecca A Meseroll
- The Laboratory of Cell and Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
| | - Orna Cohen-Fix
- The Laboratory of Cell and Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
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46
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Cairo L, Wozniak R. The Nuclear Transport Factor Kap121 Is Required for Stability of the Dam1 Complex and Mitotic Kinetochore Bi-orientation. Cell Rep 2016; 14:2440-50. [DOI: 10.1016/j.celrep.2016.02.041] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Revised: 11/04/2015] [Accepted: 02/04/2016] [Indexed: 12/30/2022] Open
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47
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Hellberg T, Paßvogel L, Schulz KS, Klupp BG, Mettenleiter TC. Nuclear Egress of Herpesviruses: The Prototypic Vesicular Nucleocytoplasmic Transport. Adv Virus Res 2016; 94:81-140. [PMID: 26997591 DOI: 10.1016/bs.aivir.2015.10.002] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Herpesvirus particles mature in two different cellular compartments. While capsid assembly and packaging of the genomic linear double-stranded DNA occur in the nucleus, virion formation takes place in the cytoplasm by the addition of numerous tegument proteins as well as acquisition of the viral envelope by budding into cellular vesicles derived from the trans-Golgi network containing virally encoded glycoproteins. To gain access to the final maturation compartment, herpesvirus nucleocapsids have to cross a formidable barrier, the nuclear envelope (NE). Since the ca. 120 nm diameter capsids are unable to traverse via nuclear pores, herpesviruses employ a vesicular transport through both leaflets of the NE. This process involves proteins which support local dissolution of the nuclear lamina to allow access of capsids to the inner nuclear membrane (INM), drive vesicle formation from the INM and mediate inclusion of the capsid as well as scission of the capsid-containing vesicle (also designated as "primary virion"). Fusion of the vesicle membrane (i.e., the "primary envelope") with the outer nuclear membrane subsequently results in release of the nucleocapsid into the cytoplasm for continuing virion morphogenesis. While this process has long been thought to be unique for herpesviruses, a similar pathway for nuclear egress of macromolecular complexes has recently been observed in Drosophila. Thus, herpesviruses may have coopted a hitherto unrecognized cellular mechanism of vesicle-mediated nucleocytoplasmic transport. This could have far reaching consequences for our understanding of cellular functions as again unraveled by the study of viruses.
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Affiliation(s)
- Teresa Hellberg
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Greifswald-Insel Riems, Germany
| | - Lars Paßvogel
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Greifswald-Insel Riems, Germany
| | - Katharina S Schulz
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Greifswald-Insel Riems, Germany
| | - Barbara G Klupp
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Greifswald-Insel Riems, Germany
| | - Thomas C Mettenleiter
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Greifswald-Insel Riems, Germany.
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48
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Bensidoun P, Raymond P, Oeffinger M, Zenklusen D. Imaging single mRNAs to study dynamics of mRNA export in the yeast Saccharomyces cerevisiae. Methods 2016; 98:104-114. [PMID: 26784711 DOI: 10.1016/j.ymeth.2016.01.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Revised: 01/12/2016] [Accepted: 01/14/2016] [Indexed: 01/08/2023] Open
Abstract
Regulation of mRNA and protein expression occurs at many levels, initiated at transcription and followed by mRNA processing, export, localization, translation and mRNA degradation. The ability to study mRNAs in living cells has become a critical tool to study and analyze how the various steps of the gene expression pathway are carried out. Here we describe a detailed protocol for real time fluorescent RNA imaging using the PP7 bacteriophage coat protein, which allows mRNA detection with high spatial and temporal resolution in the yeast Saccharomyces cerevisiae, and can be applied to study various stages of mRNA metabolism. We describe the different parameters required for quantitative single molecule imaging in yeast, including strategies for genomic integration, expression of a PP7 coat protein GFP fusion protein, microscope setup and analysis strategies. We illustrate the method's use by analyzing the behavior of nuclear mRNA in yeast and the role of the nuclear basket in mRNA export.
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Affiliation(s)
- Pierre Bensidoun
- Département de Biochimieet médecine moléculaire, Faculté de médecine, Université de Montréal, Montréal, Québec H3C 3J7, Canada; Institut de recherches cliniques de Montréal, 110 Avenue des Pins Ouest, Montréal, Québec H2W 1R7, Canada
| | - Pascal Raymond
- Département de Biochimieet médecine moléculaire, Faculté de médecine, Université de Montréal, Montréal, Québec H3C 3J7, Canada
| | - Marlene Oeffinger
- Département de Biochimieet médecine moléculaire, Faculté de médecine, Université de Montréal, Montréal, Québec H3C 3J7, Canada; Institut de recherches cliniques de Montréal, 110 Avenue des Pins Ouest, Montréal, Québec H2W 1R7, Canada; Faculty of Medicine, Division of Experimental Medicine, McGill University, Montréal, Québec H3A 1A3, Canada
| | - Daniel Zenklusen
- Département de Biochimieet médecine moléculaire, Faculté de médecine, Université de Montréal, Montréal, Québec H3C 3J7, Canada.
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Liu G, Yong MYJ, Yurieva M, Srinivasan KG, Liu J, Lim JSY, Poidinger M, Wright GD, Zolezzi F, Choi H, Pavelka N, Rancati G. Gene Essentiality Is a Quantitative Property Linked to Cellular Evolvability. Cell 2015; 163:1388-99. [PMID: 26627736 DOI: 10.1016/j.cell.2015.10.069] [Citation(s) in RCA: 102] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Revised: 08/01/2015] [Accepted: 10/20/2015] [Indexed: 11/24/2022]
Abstract
Gene essentiality is typically determined by assessing the viability of the corresponding mutant cells, but this definition fails to account for the ability of cells to adaptively evolve to genetic perturbations. Here, we performed a stringent screen to assess the degree to which Saccharomyces cerevisiae cells can survive the deletion of ~1,000 individual "essential" genes and found that ~9% of these genetic perturbations could in fact be overcome by adaptive evolution. Our analyses uncovered a genome-wide gradient of gene essentiality, with certain essential cellular functions being more "evolvable" than others. Ploidy changes were prevalent among the evolved mutant strains, and aneuploidy of a specific chromosome was adaptive for a class of evolvable nucleoporin mutants. These data justify a quantitative redefinition of gene essentiality that incorporates both viability and evolvability of the corresponding mutant cells and will enable selection of therapeutic targets associated with lower risk of emergence of drug resistance.
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Affiliation(s)
- Gaowen Liu
- Institute of Medical Biology (IMB), Agency for Science, Technology and Research (A(∗)STAR), Singapore 138648, Singapore; School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Mei Yun Jacy Yong
- Institute of Medical Biology (IMB), Agency for Science, Technology and Research (A(∗)STAR), Singapore 138648, Singapore
| | - Marina Yurieva
- Singapore Immunology Network (SIgN), A(∗)STAR, Singapore 138648, Singapore
| | | | - Jaron Liu
- Institute of Medical Biology (IMB), Agency for Science, Technology and Research (A(∗)STAR), Singapore 138648, Singapore
| | - John Soon Yew Lim
- Institute of Medical Biology (IMB), Agency for Science, Technology and Research (A(∗)STAR), Singapore 138648, Singapore
| | - Michael Poidinger
- Singapore Immunology Network (SIgN), A(∗)STAR, Singapore 138648, Singapore
| | - Graham Daniel Wright
- Institute of Medical Biology (IMB), Agency for Science, Technology and Research (A(∗)STAR), Singapore 138648, Singapore
| | - Francesca Zolezzi
- Singapore Immunology Network (SIgN), A(∗)STAR, Singapore 138648, Singapore
| | - Hyungwon Choi
- Saw Swee Hock School of Public Health, National University of Singapore (NUS) and National University Health System, Singapore 117549, Singapore
| | - Norman Pavelka
- Singapore Immunology Network (SIgN), A(∗)STAR, Singapore 138648, Singapore.
| | - Giulia Rancati
- Institute of Medical Biology (IMB), Agency for Science, Technology and Research (A(∗)STAR), Singapore 138648, Singapore; School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore.
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50
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Sec66-Dependent Regulation of Yeast Spindle-Pole Body Duplication Through Pom152. Genetics 2015; 201:1479-95. [PMID: 26510791 PMCID: PMC4676539 DOI: 10.1534/genetics.115.178012] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Accepted: 10/23/2015] [Indexed: 02/06/2023] Open
Abstract
In closed mitotic systems such as Saccharomyces cerevisiae, the nuclear envelope (NE) does not break down during mitosis, so microtubule-organizing centers such as the spindle-pole body (SPB) must be inserted into the NE to facilitate bipolar spindle formation and chromosome segregation. The mechanism of SPB insertion has been linked to NE insertion of nuclear pore complexes (NPCs) through a series of genetic and physical interactions between NPCs and SPB components. To identify new genes involved in SPB duplication and NE insertion, we carried out genome-wide screens for suppressors of deletion alleles of SPB components, including Mps3 and Mps2. In addition to the nucleoporins POM152 and POM34, we found that elimination of SEC66/SEC71/KAR7 suppressed lethality of cells lacking MPS2 or MPS3. Sec66 is a nonessential subunit of the Sec63 complex that functions together with the Sec61 complex in import of proteins into the endoplasmic reticulum (ER). Cells lacking Sec66 have reduced levels of Pom152 protein but not Pom34 or Ndc1, a shared component of the NPC and SPB. The fact that Sec66 but not other subunits of the ER translocon bypass deletion mutants in SPB genes suggests a specific role for Sec66 in the control of Pom152 levels. Based on the observation that sec66∆ does not affect the distribution of Ndc1 on the NE or Ndc1 binding to the SPB, we propose that Sec66-mediated regulation of Pom152 plays an NPC-independent role in the control of SPB duplication.
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