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Matsuda A, Mansour A, Mofrad MRK. Deciphering the intrinsically disordered characteristics of the FG-Nups through the lens of polymer physics. Nucleus 2024; 15:2399247. [PMID: 39282864 PMCID: PMC11407397 DOI: 10.1080/19491034.2024.2399247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/19/2024] Open
Abstract
The nuclear pore complex (NPC) is a critical gateway regulating molecular transport between the nucleus and cytoplasm. It allows small molecules to pass freely, while larger molecules require nuclear transport receptors to traverse the barrier. This selective permeability is maintained by phenylalanine-glycine-rich nucleoporins (FG-Nups), intrinsically disordered proteins that fill the NPC's central channel. The disordered and flexible nature of FG-Nups complicates their spatial characterization with conventional structural biology techniques. To address this challenge, polymer physics offers a valuable framework for describing FG-Nup behavior, reducing their complex structures to a few key parameters. In this review, we explore how polymer physics models FG-Nups using these parameters and discuss experimental efforts to quantify them in various contexts, providing insights into the conformational properties of FG-Nups.
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Affiliation(s)
- Atsushi Matsuda
- Molecular Cell Biomechanics Laboratory, Departments of Bioengineering and Mechanical Engineering, University of California Berkeley, Berkeley, CA, USA
| | - Abdullah Mansour
- Molecular Cell Biomechanics Laboratory, Departments of Bioengineering and Mechanical Engineering, University of California Berkeley, Berkeley, CA, USA
| | - Mohammad R K Mofrad
- Molecular Cell Biomechanics Laboratory, Departments of Bioengineering and Mechanical Engineering, University of California Berkeley, Berkeley, CA, USA
- Molecular Biophysics and Integrative Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
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2
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Moschonas GD, Delhaye L, Cooreman R, Hüsers F, Bhat A, Stylianidou Z, De Bousser E, De Pryck L, Grzesik H, De Sutter D, Parthoens E, De Smet AS, Maciejczuk A, Lippens S, Callewaert N, Vandekerckhove L, Debyser Z, Sodeik B, Eyckerman S, Saelens X. MX2 forms nucleoporin-comprising cytoplasmic biomolecular condensates that lure viral capsids. Cell Host Microbe 2024; 32:1705-1724.e14. [PMID: 39389033 DOI: 10.1016/j.chom.2024.09.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 02/01/2024] [Accepted: 09/09/2024] [Indexed: 10/12/2024]
Abstract
Human myxovirus resistance 2 (MX2) can restrict HIV-1 and herpesviruses at a post-entry step through a process requiring an interaction between MX2 and the viral capsids. The involvement of other host cell factors, however, remains poorly understood. Here, we mapped the proximity interactome of MX2, revealing strong enrichment of phenylalanine-glycine (FG)-rich proteins related to the nuclear pore complex as well as proteins that are part of cytoplasmic ribonucleoprotein granules. MX2 interacted with these proteins to form multiprotein cytoplasmic biomolecular condensates that were essential for its anti-HIV-1 and anti-herpes simplex virus 1 (HSV-1) activity. MX2 condensate formation required the disordered N-terminal region and MX2 dimerization. Incoming HIV-1 and HSV-1 capsids associated with MX2 at these dynamic cytoplasmic biomolecular condensates, preventing nuclear entry of their viral genomes. Thus, MX2 forms cytoplasmic condensates that likely act as nuclear pore decoys, trapping capsids and inducing premature viral genome release to interfere with nuclear targeting of HIV-1 and HSV-1.
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Affiliation(s)
- George D Moschonas
- VIB Center for Medical Biotechnology, VIB, Technologiepark-Zwijnaarde 75, 9052 Ghent, Belgium; Department of Biochemistry and Microbiology, Ghent University, Technologiepark-Zwijnaarde 75, 9052 Ghent, Belgium
| | - Louis Delhaye
- VIB Center for Medical Biotechnology, VIB, Technologiepark-Zwijnaarde 75, 9052 Ghent, Belgium; Department of Biomolecular Medicine, Ghent University, Technologiepark-Zwijnaarde 75, 9052 Ghent, Belgium
| | - Robin Cooreman
- VIB Center for Medical Biotechnology, VIB, Technologiepark-Zwijnaarde 75, 9052 Ghent, Belgium; Department of Biochemistry and Microbiology, Ghent University, Technologiepark-Zwijnaarde 75, 9052 Ghent, Belgium
| | - Franziska Hüsers
- Institute of Virology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany; RESIST-Cluster of Excellence, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany
| | - Anayat Bhat
- Department of Pharmacological and Pharmaceutical Sciences, Laboratory of Molecular Virology and Gene Therapy, KU Leuven, Herestraat 49, 3000 Leuven, Belgium
| | - Zoe Stylianidou
- HIV Cure Research Center, Department of Internal Medicine and Pediatrics, Ghent University, 9000 Ghent, Belgium
| | - Elien De Bousser
- VIB Center for Medical Biotechnology, VIB, Technologiepark-Zwijnaarde 75, 9052 Ghent, Belgium; Department of Biochemistry and Microbiology, Ghent University, Technologiepark-Zwijnaarde 75, 9052 Ghent, Belgium; Cancer Research Institute Ghent (CRIG), Ghent, Belgium
| | - Laure De Pryck
- VIB Center for Medical Biotechnology, VIB, Technologiepark-Zwijnaarde 75, 9052 Ghent, Belgium; Department of Biochemistry and Microbiology, Ghent University, Technologiepark-Zwijnaarde 75, 9052 Ghent, Belgium; Cancer Research Institute Ghent (CRIG), Ghent, Belgium
| | - Hanna Grzesik
- VIB Center for Medical Biotechnology, VIB, Technologiepark-Zwijnaarde 75, 9052 Ghent, Belgium; Department of Biomolecular Medicine, Ghent University, Technologiepark-Zwijnaarde 75, 9052 Ghent, Belgium
| | - Delphine De Sutter
- VIB Center for Medical Biotechnology, VIB, Technologiepark-Zwijnaarde 75, 9052 Ghent, Belgium; Department of Biomolecular Medicine, Ghent University, Technologiepark-Zwijnaarde 75, 9052 Ghent, Belgium
| | - Eef Parthoens
- VIB Center for Inflammation Research, Technologiepark-Zwijnaarde 71, 9052 Ghent, Belgium; Department of Biomedical Molecular Biology, Ghent University, 9052 Ghent, Belgium; VIB BioImaging Core, VIB, 9052 Ghent, Belgium
| | - Anne-Sophie De Smet
- VIB Center for Medical Biotechnology, VIB, Technologiepark-Zwijnaarde 75, 9052 Ghent, Belgium; Department of Biochemistry and Microbiology, Ghent University, Technologiepark-Zwijnaarde 75, 9052 Ghent, Belgium
| | - Aleksandra Maciejczuk
- VIB Center for Medical Biotechnology, VIB, Technologiepark-Zwijnaarde 75, 9052 Ghent, Belgium; Department of Biomolecular Medicine, Ghent University, Technologiepark-Zwijnaarde 75, 9052 Ghent, Belgium
| | - Saskia Lippens
- VIB Center for Inflammation Research, Technologiepark-Zwijnaarde 71, 9052 Ghent, Belgium; VIB BioImaging Core, VIB, 9052 Ghent, Belgium
| | - Nico Callewaert
- VIB Center for Medical Biotechnology, VIB, Technologiepark-Zwijnaarde 75, 9052 Ghent, Belgium; Department of Biochemistry and Microbiology, Ghent University, Technologiepark-Zwijnaarde 75, 9052 Ghent, Belgium
| | - Linos Vandekerckhove
- HIV Cure Research Center, Department of Internal Medicine and Pediatrics, Ghent University, 9000 Ghent, Belgium
| | - Zeger Debyser
- Department of Pharmacological and Pharmaceutical Sciences, Laboratory of Molecular Virology and Gene Therapy, KU Leuven, Herestraat 49, 3000 Leuven, Belgium
| | - Beate Sodeik
- Institute of Virology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany; RESIST-Cluster of Excellence, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany; DZIF-German Centre for Infection Research, Partner site Hannover-Braunschweig, Germany
| | - Sven Eyckerman
- VIB Center for Medical Biotechnology, VIB, Technologiepark-Zwijnaarde 75, 9052 Ghent, Belgium; Department of Biomolecular Medicine, Ghent University, Technologiepark-Zwijnaarde 75, 9052 Ghent, Belgium.
| | - Xavier Saelens
- VIB Center for Medical Biotechnology, VIB, Technologiepark-Zwijnaarde 75, 9052 Ghent, Belgium; Department of Biochemistry and Microbiology, Ghent University, Technologiepark-Zwijnaarde 75, 9052 Ghent, Belgium.
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3
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Otto TA, Bergsma T, Dekker M, Mouton SN, Gallardo P, Wolters JC, Steen A, Onck PR, Veenhoff LM. Nucleoporin Nsp1 surveils the phase state of FG-Nups. Cell Rep 2024; 43:114793. [PMID: 39356635 DOI: 10.1016/j.celrep.2024.114793] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 06/21/2024] [Accepted: 09/07/2024] [Indexed: 10/04/2024] Open
Abstract
Transport through the nuclear pore complex (NPC) relies on intrinsically disordered FG-nucleoporins (FG-Nups) forming a selective barrier. Away from the NPC, FG-Nups readily form condensates and aggregates, and we address how this behavior is surveilled in cells. FG-Nups, including Nsp1, together with the nuclear transport receptor Kap95, form a native daughter cell-specific cytosolic condensate in yeast. In aged cells, this condensate disappears as cytosolic Nsp1 levels decline. Biochemical assays and modeling show that Nsp1 is a modulator of FG-Nup condensates, promoting a liquid-like state. Nsp1's presence in the cytosol and condensates is critical, as a reduction of cytosolic levels in young cells induces NPC defects and a general decline in protein quality control that quantitatively mimics aging phenotypes. These phenotypes can be rescued by a cytosolic form of Nsp1. We conclude that Nsp1 is a phase state regulator that surveils FG-Nups and impacts general protein homeostasis.
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Affiliation(s)
- Tegan A Otto
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center Groningen, 9713AV Groningen, the Netherlands
| | - Tessa Bergsma
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center Groningen, 9713AV Groningen, the Netherlands
| | - Maurice Dekker
- Zernike Institute for Advanced Materials, University of Groningen, 9747AG Groningen, the Netherlands
| | - Sara N Mouton
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center Groningen, 9713AV Groningen, the Netherlands
| | - Paola Gallardo
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center Groningen, 9713AV Groningen, the Netherlands
| | - Justina C Wolters
- Laboratory of Pediatrics, University of Groningen, University Medical Center Groningen, 9713AV Groningen, the Netherlands
| | - Anton Steen
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center Groningen, 9713AV Groningen, the Netherlands
| | - Patrick R Onck
- Zernike Institute for Advanced Materials, University of Groningen, 9747AG Groningen, the Netherlands
| | - Liesbeth M Veenhoff
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center Groningen, 9713AV Groningen, the Netherlands.
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4
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Yao L, Li Y, Wang P, Xu C, Yu Z. Nucleoporin-associated steroid-resistant nephrotic syndrome. Pediatr Nephrol 2024:10.1007/s00467-024-06494-3. [PMID: 39331077 DOI: 10.1007/s00467-024-06494-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2024] [Revised: 08/01/2024] [Accepted: 08/07/2024] [Indexed: 09/28/2024]
Abstract
Nucleoporins (Nups) are a class of proteins that assemble to form nuclear pore complexes, which are related to nucleocytoplasmic transport, gene expression, and the cell cycle. Pathogenic variants in six genes encoding Nups, NUP85, NUP93, NUP107, NUP133, NUP160, and NUP205, cause monogenic steroid-resistant nephrotic syndrome (SRNS), referred to as nucleoporin-associated SRNS. In this paper, we review the epidemiology, structure and function of Nups, pathogenesis, phenotypes and genotypes, and management of nucleoporin-associated SRNS as well as implications for genetic counseling. Affected individuals exhibit autosomal recessive isolated and syndromic SRNS, whose extrarenal manifestations include neurological disorders, growth and development disorders, cardiovascular disorders, and congenital malformations. The median ages at onset of NUP85-, NUP93-, NUP107-, NUP133-, NUP160-, and NUP205-associated SRNS are 7, 3, 4.1, 9, 7, and 2 years, respectively. Kidney biopsies reveal focal segmental glomerulosclerosis in 89% of patients. Most affected individuals are resistant to immunosuppressants. For the six subtypes of nucleoporin-associated SRNS, patients show progression to kidney failure at median ages of 8.5, 3.7, 6.9, 13, 15, and 7 years, respectively. Only two patients with NUP93-associated SRNS with nephrotic syndrome relapse post-transplant have been reported, and the recurrence rate is 12.5%. Next-generation sequencing using a targeted gene panel is recommended in cases of suspected nucleoporin-associated SRNS for genetic diagnosis. Renin-angiotensin-aldosterone system inhibitors are recommended for patients with nucleoporin-associated SRNS. Once genetic diagnosis is confirmed, immunosuppressant discontinuation should be considered, and kidney transplant is preferred when patients progress to kidney failure. Genetic counselling should be provided for asymptomatic siblings and future siblings of an affected individual. Further studies on the pathogenesis of nucleoporin-associated SRNS are needed to seek new therapeutic interventions.
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Affiliation(s)
- Ling Yao
- Department of Nephrology, Rheumatology and Immunology, Fujian Children's Hospital, College of Clinical Medicine for Obstetrics & Gynecology and Pediatrics, Fujian Medical University, 966 Heng Yu Road, Jin'an District, Fuzhou, 350014, Fujian, People's Republic of China
| | - Yuanyuan Li
- Department of Nephrology, Rheumatology and Immunology, Fujian Children's Hospital, College of Clinical Medicine for Obstetrics & Gynecology and Pediatrics, Fujian Medical University, 966 Heng Yu Road, Jin'an District, Fuzhou, 350014, Fujian, People's Republic of China
| | - Ping Wang
- Department of Pediatrics, The Military Hospital of 92435 Unit of PLA, Ningde, 352103, China
| | - Chan Xu
- Department of Nephrology, Rheumatology and Immunology, Fujian Children's Hospital, College of Clinical Medicine for Obstetrics & Gynecology and Pediatrics, Fujian Medical University, 966 Heng Yu Road, Jin'an District, Fuzhou, 350014, Fujian, People's Republic of China
| | - Zihua Yu
- Department of Nephrology, Rheumatology and Immunology, Fujian Children's Hospital, College of Clinical Medicine for Obstetrics & Gynecology and Pediatrics, Fujian Medical University, 966 Heng Yu Road, Jin'an District, Fuzhou, 350014, Fujian, People's Republic of China.
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5
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Li Y, Zhu J, Zhai F, Kong L, Li H, Jin X. Advances in the understanding of nuclear pore complexes in human diseases. J Cancer Res Clin Oncol 2024; 150:374. [PMID: 39080077 PMCID: PMC11289042 DOI: 10.1007/s00432-024-05881-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2024] [Accepted: 07/03/2024] [Indexed: 08/02/2024]
Abstract
BACKGROUND Nuclear pore complexes (NPCs) are sophisticated and dynamic protein structures that straddle the nuclear envelope and act as gatekeepers for transporting molecules between the nucleus and the cytoplasm. NPCs comprise up to 30 different proteins known as nucleoporins (NUPs). However, a growing body of research has suggested that NPCs play important roles in gene regulation, viral infections, cancer, mitosis, genetic diseases, kidney diseases, immune system diseases, and degenerative neurological and muscular pathologies. PURPOSE In this review, we introduce the structure and function of NPCs. Then We described the physiological and pathological effects of each component of NPCs which provide a direction for future clinical applications. METHODS The literatures from PubMed have been reviewed for this article. CONCLUSION This review summarizes current studies on the implications of NPCs in human physiology and pathology, highlighting the mechanistic underpinnings of NPC-associated diseases.
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Affiliation(s)
- Yuxuan Li
- The Affiliated Lihuili Hospital of Ningbo University, Ningbo, 315040, Zhejiang, China
- Department of Biochemistry and Molecular Biology, and Zhejiang Key Laboratory of Pathophysiology, Health Science Center, Nngbo University, Ningbo, 315211, Zhejiang, China
| | - Jie Zhu
- The Affiliated Lihuili Hospital of Ningbo University, Ningbo, 315040, Zhejiang, China
| | - Fengguang Zhai
- Department of Biochemistry and Molecular Biology, and Zhejiang Key Laboratory of Pathophysiology, Health Science Center, Nngbo University, Ningbo, 315211, Zhejiang, China
| | - Lili Kong
- Department of Biochemistry and Molecular Biology, and Zhejiang Key Laboratory of Pathophysiology, Health Science Center, Nngbo University, Ningbo, 315211, Zhejiang, China
| | - Hong Li
- The Affiliated Lihuili Hospital of Ningbo University, Ningbo, 315040, Zhejiang, China.
- Department of Biochemistry and Molecular Biology, and Zhejiang Key Laboratory of Pathophysiology, Health Science Center, Nngbo University, Ningbo, 315211, Zhejiang, China.
| | - Xiaofeng Jin
- The Affiliated Lihuili Hospital of Ningbo University, Ningbo, 315040, Zhejiang, China.
- Department of Biochemistry and Molecular Biology, and Zhejiang Key Laboratory of Pathophysiology, Health Science Center, Nngbo University, Ningbo, 315211, Zhejiang, China.
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6
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Khakwani MMAK, Ji XY, Khattak S, Sun YC, Yao K, Zhang L. Targeting colorectal cancer at the level of nuclear pore complex. J Adv Res 2024:S2090-1232(24)00245-5. [PMID: 38876192 DOI: 10.1016/j.jare.2024.06.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2024] [Revised: 05/23/2024] [Accepted: 06/07/2024] [Indexed: 06/16/2024] Open
Abstract
BACKGROUND Nuclear pore complexes (NPCs) are the architectures entrenched in nuclear envelop of a cell that regulate the nucleo-cytoplasmic transportation of materials, such as proteins and RNAs for proper functioning of a cell. The appropriate localization of proteins and RNAs within the cell is essential for its normal functionality. For such a complex transportation of materials across the NPC, around 60 proteins are involved comprising nucleoporins, karyopherins and RAN system proteins that play a vital role in NPC's structure formation, cargo translocation across NPC, and cargoes' rapid directed transportation respectively. In various cancers, the structure and function of NPC is often exaggerated, following altered expressions of its nucleoporins and karyopherins, affecting other proteins of associated signaling pathways. Some inhibitors of karyopherins at present, have potential to regulate the altered level/expression of these karyopherin molecules. AIM OF REVIEW This review summarizes the data from 1990 to 2023, mainly focusing on recent studies that illustrate the structure and function of NPC, the relationship and mechanisms of nucleoporins and karyopherins with colorectal cancer, as well as therapeutic values, in order to understand the pathology and underlying basis of colorectal cancer associated with NPC. This is the first review to our knowledge elucidating the detailed updated studies targeting colorectal cancer at NPC. The review also aims to target certain karyopherins, Nups and their possible inhibitors and activators molecules as a therapeutic strategy. KEY SCIENTIFIC CONCEPTS OF REVIEW NPC structure provides understanding, how nucleoporins and karyopherins as key molecules are responsible for appropriate nucleocytoplasmic transportation. Many studies provide evidences, describing the role of disrupted nucleoporins and karyopherins not only in CRC but also in other non-hematological and hematological malignancies. At present, some inhibitors of karyopherins have therapeutic potential for CRC, however development of more potent inhibitors may provide more effective therapeutic strategies for CRC in near future.
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Affiliation(s)
- Muhammad Mahtab Aslam Khan Khakwani
- Department of General Surgery, Huaihe Hospital of Henan University, Henan University, Kaifeng 475004, China; Henan International Joint Laboratory for Nuclear Protein Regulation, School of Basic Medicine, Henan University, Kaifeng, Henan 475004, China
| | - Xin-Ying Ji
- Department of Oncology, Huaxian County Hospital, Huaxian, Henan Province 456400, China; Faculty of Basic Medical Subjects, Shu-Qing Medical College of Zhengzhou, Gong-Ming Rd, Mazhai Town, Erqi District, Zhengzhou, Henan 450064, China
| | - Saadullah Khattak
- Department of General Surgery, Huaihe Hospital of Henan University, Henan University, Kaifeng 475004, China
| | - Ying-Chuan Sun
- Department of Internal Oncology (Section I), Xuchang Municipal Central Hospital, Xuchang, Henan 430000, China
| | - Kunhou Yao
- Department of General Surgery, Huaihe Hospital of Henan University, Henan University, Kaifeng 475004, China.
| | - Lei Zhang
- Department of General Surgery, Huaihe Hospital of Henan University, Henan University, Kaifeng 475004, China; Henan International Joint Laboratory for Nuclear Protein Regulation, School of Basic Medicine, Henan University, Kaifeng, Henan 475004, China.
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7
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Panagaki F, Tapia-Rojo R, Zhu T, Milmoe N, Paracuellos P, Board S, Mora M, Walker J, Rostkova E, Stannard A, Infante E, Garcia-Manyes S. Structural anisotropy results in mechano-directional transport of proteins across nuclear pores. NATURE PHYSICS 2024; 20:1180-1193. [PMID: 39036650 PMCID: PMC11254768 DOI: 10.1038/s41567-024-02438-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Accepted: 02/08/2024] [Indexed: 07/23/2024]
Abstract
The nuclear pore complex regulates nucleocytoplasmic transport by means of a tightly synchronized suite of biochemical reactions. The physicochemical properties of the translocating cargos are emerging as master regulators of their shuttling dynamics. As well as being affected by molecular weight and surface-exposed amino acids, the kinetics of the nuclear translocation of protein cargos also depend on their nanomechanical properties, yet the mechanisms underpinning the mechanoselectivity of the nuclear pore complex are unclear. Here we show that proteins with locally soft regions in the vicinity of the nuclear-localization sequence exhibit higher nuclear-import rates, and that such mechanoselectivity is specifically impaired upon knocking down nucleoporin 153, a key protein in the nuclear pore complex. This allows us to design a short, easy-to-express and chemically inert unstructured peptide tag that accelerates the nuclear-import rate of stiff protein cargos. We also show that U2OS osteosarcoma cells expressing the peptide-tagged myocardin-related transcription factor import this mechanosensitive protein to the nucleus at higher rates and display faster motility. Locally unstructured regions lower the free-energy barrier of protein translocation and might offer a control mechanism for nuclear mechanotransduction.
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Affiliation(s)
- Fani Panagaki
- Single Molecule Mechanobiology Laboratory, The Francis Crick Institute, London, UK
- Department of Physics, Randall Centre for Cell and Molecular Biophysics, Centre for the Physical Science of Life and London Centre for Nanotechnology, King’s College London, London, UK
| | - Rafael Tapia-Rojo
- Single Molecule Mechanobiology Laboratory, The Francis Crick Institute, London, UK
- Department of Physics, Randall Centre for Cell and Molecular Biophysics, Centre for the Physical Science of Life and London Centre for Nanotechnology, King’s College London, London, UK
| | - Tong Zhu
- Single Molecule Mechanobiology Laboratory, The Francis Crick Institute, London, UK
- Department of Physics, Randall Centre for Cell and Molecular Biophysics, Centre for the Physical Science of Life and London Centre for Nanotechnology, King’s College London, London, UK
| | - Natalie Milmoe
- Single Molecule Mechanobiology Laboratory, The Francis Crick Institute, London, UK
- Department of Physics, Randall Centre for Cell and Molecular Biophysics, Centre for the Physical Science of Life and London Centre for Nanotechnology, King’s College London, London, UK
| | - Patricia Paracuellos
- Single Molecule Mechanobiology Laboratory, The Francis Crick Institute, London, UK
- Department of Physics, Randall Centre for Cell and Molecular Biophysics, Centre for the Physical Science of Life and London Centre for Nanotechnology, King’s College London, London, UK
| | - Stephanie Board
- Single Molecule Mechanobiology Laboratory, The Francis Crick Institute, London, UK
- Department of Physics, Randall Centre for Cell and Molecular Biophysics, Centre for the Physical Science of Life and London Centre for Nanotechnology, King’s College London, London, UK
| | - Marc Mora
- Single Molecule Mechanobiology Laboratory, The Francis Crick Institute, London, UK
- Department of Physics, Randall Centre for Cell and Molecular Biophysics, Centre for the Physical Science of Life and London Centre for Nanotechnology, King’s College London, London, UK
| | - Jane Walker
- Single Molecule Mechanobiology Laboratory, The Francis Crick Institute, London, UK
- Department of Physics, Randall Centre for Cell and Molecular Biophysics, Centre for the Physical Science of Life and London Centre for Nanotechnology, King’s College London, London, UK
| | - Elena Rostkova
- Department of Physics, Randall Centre for Cell and Molecular Biophysics, Centre for the Physical Science of Life and London Centre for Nanotechnology, King’s College London, London, UK
| | - Andrew Stannard
- Department of Physics, Randall Centre for Cell and Molecular Biophysics, Centre for the Physical Science of Life and London Centre for Nanotechnology, King’s College London, London, UK
| | - Elvira Infante
- Single Molecule Mechanobiology Laboratory, The Francis Crick Institute, London, UK
- Department of Physics, Randall Centre for Cell and Molecular Biophysics, Centre for the Physical Science of Life and London Centre for Nanotechnology, King’s College London, London, UK
| | - Sergi Garcia-Manyes
- Single Molecule Mechanobiology Laboratory, The Francis Crick Institute, London, UK
- Department of Physics, Randall Centre for Cell and Molecular Biophysics, Centre for the Physical Science of Life and London Centre for Nanotechnology, King’s College London, London, UK
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8
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Zheng T, Zilman A. Kinetic cooperativity resolves bidirectional clogging within the nuclear pore complex. Biophys J 2024; 123:1085-1097. [PMID: 38640928 PMCID: PMC11079998 DOI: 10.1016/j.bpj.2024.03.027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 12/06/2023] [Accepted: 03/22/2024] [Indexed: 04/21/2024] Open
Abstract
As the main gatekeeper of the nucleocytoplasmic transport in eukaryotic cells, the nuclear pore complex (NPC) faces the daunting task of facilitating the bidirectional transport of a high volume of macromolecular cargoes while ensuring the selectivity, speed, and efficiency of this process. The competition between opposing nuclear import and export fluxes passing through the same channel is expected to pose a major challenge to transport efficiency. It has been suggested that phase separation-like radial segregation of import and export fluxes within the assembly of intrinsically disordered proteins that line the NPC pore could be a mechanism for ensuring efficient bidirectional transport. We examine the impact of radial segregation on the efficiency of bidirectional transport through the NPC using a coarse-grained computational model of the NPC. We find little evidence that radial segregation improves transport efficiency. By contrast, surprisingly, we find that NTR crowding may enhance rather than impair the efficiency of bidirectional transport although it decreases the available space in the pore. We identify mechanisms of this novel crowding-induced transport cooperativity through the self-regulation of cargo density and flux in the pore. These findings explain how the functional architecture of the NPC resolves the problem of efficient bidirectional transport, and provide inspiration for the alleviation of clogging in artificial selective nanopores.
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Affiliation(s)
- Tiantian Zheng
- Department of Physics, University of Toronto, Toronto, ON, Canada
| | - Anton Zilman
- Department of Physics, University of Toronto, Toronto, ON, Canada.
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9
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Fu L, Weiskopf EN, Akkermans O, Swanson NA, Cheng S, Schwartz TU, Görlich D. HIV-1 capsids enter the FG phase of nuclear pores like a transport receptor. Nature 2024; 626:843-851. [PMID: 38267583 PMCID: PMC10881386 DOI: 10.1038/s41586-023-06966-w] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Accepted: 12/13/2023] [Indexed: 01/26/2024]
Abstract
HIV-1 infection requires nuclear entry of the viral genome. Previous evidence suggests that this entry proceeds through nuclear pore complexes (NPCs), with the 120 × 60 nm capsid squeezing through an approximately 60-nm-wide central channel1 and crossing the permeability barrier of the NPC. This barrier can be described as an FG phase2 that is assembled from cohesively interacting phenylalanine-glycine (FG) repeats3 and is selectively permeable to cargo captured by nuclear transport receptors (NTRs). Here we show that HIV-1 capsid assemblies can target NPCs efficiently in an NTR-independent manner and bind directly to several types of FG repeats, including barrier-forming cohesive repeats. Like NTRs, the capsid readily partitions into an in vitro assembled cohesive FG phase that can serve as an NPC mimic and excludes much smaller inert probes such as mCherry. Indeed, entry of the capsid protein into such an FG phase is greatly enhanced by capsid assembly, which also allows the encapsulated clients to enter. Thus, our data indicate that the HIV-1 capsid behaves like an NTR, with its interior serving as a cargo container. Because capsid-coating with trans-acting NTRs would increase the diameter by 10 nm or more, we suggest that such a 'self-translocating' capsid undermines the size restrictions imposed by the NPC scaffold, thereby bypassing an otherwise effective barrier to viral infection.
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Affiliation(s)
- Liran Fu
- Department of Cellular Logistics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Erika N Weiskopf
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Onno Akkermans
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Nicholas A Swanson
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Shiya Cheng
- Department of Meiosis, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Thomas U Schwartz
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA.
| | - Dirk Görlich
- Department of Cellular Logistics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany.
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10
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Sipko EL, Chappell GF, Berlow RB. Multivalency emerges as a common feature of intrinsically disordered protein interactions. Curr Opin Struct Biol 2024; 84:102742. [PMID: 38096754 DOI: 10.1016/j.sbi.2023.102742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 11/20/2023] [Accepted: 11/22/2023] [Indexed: 02/09/2024]
Abstract
Intrinsically disordered proteins (IDPs) use their unique molecular properties and conformational plasticity to interact with cellular partners in a wide variety of biological contexts. Multivalency is an important feature of IDPs that allows for utilization of an expanded toolkit for interactions with other macromolecules and confers additional complexity to molecular recognition processes. Recent studies have offered insights into how multivalent interactions of IDPs enable responsive and sensitive regulation in the context of transcription and cellular signaling. Multivalency is also widely recognized as an important feature of IDP interactions that mediate formation of biomolecular condensates. We highlight recent examples of multivalent interactions of IDPs across diverse contexts to illustrate the breadth of biological processes that utilize multivalency in molecular interactions.
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Affiliation(s)
- Emily L Sipko
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Garrett F Chappell
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Rebecca B Berlow
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
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11
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Raveh B, Eliasian R, Rashkovits S, Russel D, Hayama R, Sparks SE, Singh D, Lim R, Villa E, Rout MP, Cowburn D, Sali A. Integrative spatiotemporal map of nucleocytoplasmic transport. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.12.31.573409. [PMID: 38260487 PMCID: PMC10802240 DOI: 10.1101/2023.12.31.573409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
The Nuclear Pore Complex (NPC) facilitates rapid and selective nucleocytoplasmic transport of molecules as large as ribosomal subunits and viral capsids. It is not clear how key emergent properties of this transport arise from the system components and their interactions. To address this question, we constructed an integrative coarse-grained Brownian dynamics model of transport through a single NPC, followed by coupling it with a kinetic model of Ran-dependent transport in an entire cell. The microscopic model parameters were fitted to reflect experimental data and theoretical information regarding the transport, without making any assumptions about its emergent properties. The resulting reductionist model is validated by reproducing several features of transport not used for its construction, such as the morphology of the central transporter, rates of passive and facilitated diffusion as a function of size and valency, in situ radial distributions of pre-ribosomal subunits, and active transport rates for viral capsids. The model suggests that the NPC functions essentially as a virtual gate whose flexible phenylalanine-glycine (FG) repeat proteins raise an entropy barrier to diffusion through the pore. Importantly, this core functionality is greatly enhanced by several key design features, including 'fuzzy' and transient interactions, multivalency, redundancy in the copy number of FG nucleoporins, exponential coupling of transport kinetics and thermodynamics in accordance with the transition state theory, and coupling to the energy-reliant RanGTP concentration gradient. These design features result in the robust and resilient rate and selectivity of transport for a wide array of cargo ranging from a few kilodaltons to megadaltons in size. By dissecting these features, our model provides a quantitative starting point for rationally modulating the transport system and its artificial mimics.
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12
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Abstract
Recent advances in the study of virus-cell interactions have improved our understanding of how viruses that replicate their genomes in the nucleus (e.g., retroviruses, hepadnaviruses, herpesviruses, and a subset of RNA viruses) hijack cellular pathways to export these genomes to the cytoplasm where they access virion egress pathways. These findings shed light on novel aspects of viral life cycles relevant to the development of new antiviral strategies and can yield new tractable, virus-based tools for exposing additional secrets of the cell. The goal of this review is to summarize defined and emerging modes of virus-host interactions that drive the transit of viral genomes out of the nucleus across the nuclear envelope barrier, with an emphasis on retroviruses that are most extensively studied. In this context, we prioritize discussion of recent progress in understanding the trafficking and function of the human immunodeficiency virus type 1 Rev protein, exemplifying a relatively refined example of stepwise, cooperativity-driven viral subversion of multi-subunit host transport receptor complexes.
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Affiliation(s)
- Ryan T. Behrens
- Department of Pathology and Laboratory Medicine, University of Wisconsin, Madison, Wisconsin, USA
| | - Nathan M. Sherer
- McArdle Laboratory for Cancer Research and Carbone Cancer Center, University of Wisconsin, Madison, Wisconsin, USA
- Institute for Molecular Virology, University of Wisconsin, Madison, Wisconsin, USA
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13
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Veldsink AC, Gallardo P, Lusk CP, Veenhoff LM. Changing the guard-nuclear pore complex quality control. FEBS Lett 2023; 597:2739-2749. [PMID: 37715940 DOI: 10.1002/1873-3468.14739] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 08/31/2023] [Accepted: 08/31/2023] [Indexed: 09/18/2023]
Abstract
The integrity of the nuclear envelope depends on the function of nuclear pore complexes (NPCs), transport channels that control macromolecular traffic between the nucleus and cytosol. The central importance of NPCs suggests the existence of quality control (QC) mechanisms that oversee their assembly and function. In this perspective, we emphasize the challenges associated with NPC assembly and the need for QC mechanisms that operate at various stages of an NPC's life. This includes cytosolic preassembly QC that helps enforce key nucleoporin-nucleoporin interactions and their ultimate stoichiometry in the NPC in addition to mechanisms that monitor aberrant fusion of the inner and outer nuclear membranes. Furthermore, we discuss whether and how these QC mechanisms may operate to sense faulty mature NPCs to facilitate their repair or removal. The so far uncovered mechanisms for NPC QC provide fertile ground for future research that not only benefits a better understanding of the vital role that NPCs play in cellular physiology but also how loss of NPC function and/or these QC mechanisms might be an input to aging and disease.
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Affiliation(s)
- Annemiek C Veldsink
- European Research Institute for the Biology of Ageing, University Medical Center Groningen, University of Groningen, Antonius Deusinglaan 1, Groningen, 9713 AV, The Netherlands
| | - Paola Gallardo
- European Research Institute for the Biology of Ageing, University Medical Center Groningen, University of Groningen, Antonius Deusinglaan 1, Groningen, 9713 AV, The Netherlands
| | - C Patrick Lusk
- Department of Cell Biology, Yale School of Medicine, CT, New Haven, USA
| | - Liesbeth M Veenhoff
- European Research Institute for the Biology of Ageing, University Medical Center Groningen, University of Groningen, Antonius Deusinglaan 1, Groningen, 9713 AV, The Netherlands
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14
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McGoldrick P, Robertson J. Unraveling the impact of disrupted nucleocytoplasmic transport systems in C9orf72-associated ALS. Front Cell Neurosci 2023; 17:1247297. [PMID: 37720544 PMCID: PMC10501458 DOI: 10.3389/fncel.2023.1247297] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2023] [Accepted: 08/08/2023] [Indexed: 09/19/2023] Open
Abstract
Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are two adult-onset neurodegenerative diseases that are part of a common disease spectrum due to clinical, genetic, and pathological overlap. A prominent genetic factor contributing to both diseases is a hexanucleotide repeat expansion in a non-coding region of the C9orf72 gene. This mutation in C9orf72 leads to nuclear depletion and cytoplasmic aggregation of Tar DNA-RNA binding protein 43 (TDP-43). TDP-43 pathology is characteristic of the majority of ALS cases, irrespective of disease causation, and is present in ~50% of FTD cases. Defects in nucleocytoplasmic transport involving the nuclear pore complex, the Ran-GTPase cycle, and nuclear transport factors have been linked with the mislocalization of TDP-43. Here, we will explore and discuss the implications of these system abnormalities of nucleocytoplasmic transport in C9orf72-ALS/FTD, as well as in other forms of familial and sporadic ALS.
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Affiliation(s)
- Philip McGoldrick
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, ON, Canada
| | - Janice Robertson
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, ON, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
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15
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Monette A, Niu M, Maldonado RK, Chang J, Lambert GS, Flanagan JM, Cochrane A, Parent LJ, Mouland AJ. Influence of HIV-1 Genomic RNA on the Formation of Gag Biomolecular Condensates. J Mol Biol 2023; 435:168190. [PMID: 37385580 PMCID: PMC10838171 DOI: 10.1016/j.jmb.2023.168190] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 06/18/2023] [Accepted: 06/20/2023] [Indexed: 07/01/2023]
Abstract
Biomolecular condensates (BMCs) play an important role in the replication of a growing number of viruses, but many important mechanistic details remain to be elucidated. Previously, we demonstrated that the pan-retroviral nucleocapsid (NC) and HIV-1 pr55Gag (Gag) proteins phase separate into condensates, and that HIV-1 protease (PR)-mediated maturation of Gag and Gag-Pol precursor proteins yields self-assembling BMCs that have HIV-1 core architecture. Using biochemical and imaging techniques, we aimed to further characterize the phase separation of HIV-1 Gag by determining which of its intrinsically disordered regions (IDRs) influence the formation of BMCs, and how the HIV-1 viral genomic RNA (gRNA) could influence BMC abundance and size. We found that mutations in the Gag matrix (MA) domain or the NC zinc finger motifs altered condensate number and size in a salt-dependent manner. Gag BMCs were also bimodally influenced by the gRNA, with a condensate-promoting regime at lower protein concentrations and a gel dissolution at higher protein concentrations. Interestingly, incubation of Gag with CD4+ T cell nuclear lysates led to the formation of larger BMCs compared to much smaller ones observed in the presence of cytoplasmic lysates. These findings suggest that the composition and properties of Gag-containing BMCs may be altered by differential association of host factors in nuclear and cytosolic compartments during virus assembly. This study significantly advances our understanding of HIV-1 Gag BMC formation and provides a foundation for future therapeutic targeting of virion assembly.
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Affiliation(s)
- Anne Monette
- Lady Davis Institute at the Jewish General Hospital, Montréal, Québec H3T 1E2, Canada
| | - Meijuan Niu
- Lady Davis Institute at the Jewish General Hospital, Montréal, Québec H3T 1E2, Canada
| | - Rebecca Kaddis Maldonado
- Department of Medicine, Pennsylvania State University College of Medicine, Hershey, PA 17033, United States; Department of Microbiology and Immunology, Pennsylvania State University College of Medicine, Hershey, PA 17033, United States
| | - Jordan Chang
- Department of Medicine, Pennsylvania State University College of Medicine, Hershey, PA 17033, United States
| | - Gregory S Lambert
- Department of Medicine, Pennsylvania State University College of Medicine, Hershey, PA 17033, United States
| | - John M Flanagan
- Department of Biochemistry and Molecular Biology, Pennsylvania State University College of Medicine, Hershey, PA 17033, United States
| | - Alan Cochrane
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Leslie J Parent
- Department of Medicine, Pennsylvania State University College of Medicine, Hershey, PA 17033, United States; Department of Microbiology and Immunology, Pennsylvania State University College of Medicine, Hershey, PA 17033, United States.
| | - Andrew J Mouland
- Lady Davis Institute at the Jewish General Hospital, Montréal, Québec H3T 1E2, Canada; Department of Medicine, McGill University, Montréal, Québec H4A 3J1, Canada.
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16
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Sarthak K, Winogradoff D, Ge Y, Myong S, Aksimentiev A. Benchmarking Molecular Dynamics Force Fields for All-Atom Simulations of Biological Condensates. J Chem Theory Comput 2023; 19:3721-3740. [PMID: 37134270 PMCID: PMC11169342 DOI: 10.1021/acs.jctc.3c00148] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Proteins containing intrinsically disordered regions are integral parts of the cellular signaling pathways and common components of biological condensates. Point mutations in the protein sequence, genetic at birth or acquired through aging, can alter the properties of the condensates, marking the onset of neurodegenerative diseases such as ALS and dementia. While the all-atom molecular dynamics method can, in principle, elucidate the conformational changes that arise from point mutations, the applications of this method to protein condensate systems is conditioned upon the availability of molecular force fields that can accurately describe both structured and disordered regions of such proteins. Using the special-purpose Anton 2 supercomputer, we benchmarked the efficacy of nine presently available molecular force fields in describing the structure and dynamics of a Fused in sarcoma (FUS) protein. Five-microsecond simulations of the full-length FUS protein characterized the effect of the force field on the global conformation of the protein, self-interactions among its side chains, solvent accessible surface area, and the diffusion constant. Using the results of dynamic light scattering as a benchmark for the FUS radius of gyration, we identified several force fields that produced FUS conformations within the experimental range. Next, we used these force fields to perform ten-microsecond simulations of two structured RNA binding domains of FUS bound to their respective RNA targets, finding the choice of the force field to affect stability of the RNA-FUS complex. Taken together, our data suggest that a combination of protein and RNA force fields sharing a common four-point water model provides an optimal description of proteins containing both disordered and structured regions and RNA-protein interactions. To make simulations of such systems available beyond the Anton 2 machines, we describe and validate implementation of the best performing force fields in a publicly available molecular dynamics program NAMD. Our NAMD implementation enables simulations of large (tens of millions of atoms) biological condensate systems and makes such simulations accessible to a broader scientific community.
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Affiliation(s)
- Kumar Sarthak
- Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61820, United States
| | - David Winogradoff
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61820, United States
- Center for the Physics of Living Cells, University of Illinois at Urbana-Champaign, Urbana, Illinois 61820, United States
| | - Yingda Ge
- Department of Biophysics, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Sua Myong
- Center for the Physics of Living Cells, University of Illinois at Urbana-Champaign, Urbana, Illinois 61820, United States
- Program in Cell, Molecular, Developmental Biology, and Biophysics, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Aleksei Aksimentiev
- Center for the Physics of Living Cells, University of Illinois at Urbana-Champaign, Urbana, Illinois 61820, United States
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17
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Kozai T, Fernandez-Martinez J, van Eeuwen T, Gallardo P, Kapinos LE, Mazur A, Zhang W, Tempkin J, Panatala R, Delgado-Izquierdo M, Raveh B, Sali A, Chait BT, Veenhoff LM, Rout MP, Lim RYH. Dynamic molecular mechanism of the nuclear pore complex permeability barrier. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.31.535055. [PMID: 37066338 PMCID: PMC10103940 DOI: 10.1101/2023.03.31.535055] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 04/29/2023]
Abstract
Nuclear pore complexes (NPCs) mediate nucleocytoplasmic transport of specific macromolecules while impeding the exchange of unsolicited material. However, key aspects of this gating mechanism remain controversial. To address this issue, we determined the nanoscopic behavior of the permeability barrier directly within yeast S. cerevisiae NPCs at transport-relevant timescales. We show that the large intrinsically disordered domains of phenylalanine-glycine repeat nucleoporins (FG Nups) exhibit highly dynamic fluctuations to create transient voids in the permeability barrier that continuously shape-shift and reseal, resembling a radial polymer brush. Together with cargo-carrying transport factors the FG domains form a feature called the central plug, which is also highly dynamic. Remarkably, NPC mutants with longer FG domains show interweaving meshwork-like behavior that attenuates nucleocytoplasmic transport in vivo. Importantly, the bona fide nanoscale NPC behaviors and morphologies are not recapitulated by in vitro FG domain hydrogels. NPCs also exclude self-assembling FG domain condensates in vivo, thereby indicating that the permeability barrier is not generated by a self-assembling phase condensate, but rather is largely a polymer brush, organized by the NPC scaffold, whose dynamic gating selectivity is strongly enhanced by the presence of transport factors.
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Affiliation(s)
- Toshiya Kozai
- Biozentrum, University of Basel, Switzerland
- Swiss Nanoscience Institute, University of Basel, Switzerland
| | - Javier Fernandez-Martinez
- Laboratory of Cellular and Structural Biology, The Rockefeller University, New York, U.S.A
- Ikerbasque, Basque Foundation for Science, Bilbao, Spain
- Instituto Biofisika (UPV/EHU, CSIC), University of the Basque Country, 48940, Leioa, Spain
| | - Trevor van Eeuwen
- Laboratory of Cellular and Structural Biology, The Rockefeller University, New York, U.S.A
| | - Paola Gallardo
- European Research Institute for the Biology of Ageing, University Medical Center Groningen, University of Groningen, Netherlands
| | | | - Adam Mazur
- Biozentrum, University of Basel, Switzerland
| | - Wenzhu Zhang
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, U.S.A
| | - Jeremy Tempkin
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, U.S.A. Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA 94158, USA. Quantitative Biosciences Institute, University of California, San Francisco, San Francisco, CA 94158, USA
| | | | | | - Barak Raveh
- School of Computer Science and Engineering, The Hebrew University of Jerusalem, Israel
| | - Andrej Sali
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, U.S.A. Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA 94158, USA. Quantitative Biosciences Institute, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Brian T. Chait
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, U.S.A
| | - Liesbeth M. Veenhoff
- European Research Institute for the Biology of Ageing, University Medical Center Groningen, University of Groningen, Netherlands
| | - Michael P. Rout
- Laboratory of Cellular and Structural Biology, The Rockefeller University, New York, U.S.A
| | - Roderick Y. H. Lim
- Biozentrum, University of Basel, Switzerland
- Swiss Nanoscience Institute, University of Basel, Switzerland
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18
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Monette A, Niu M, Maldonado RK, Chang J, Lambert GS, Flanagan JM, Cochrane A, Parent LJ, Mouland AJ. Influence of HIV-1 genomic RNA on the formation of Gag biomolecular condensates. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.23.529585. [PMID: 36865181 PMCID: PMC9980109 DOI: 10.1101/2023.02.23.529585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
Abstract
Biomolecular condensates (BMCs) play an important role in the replication of a growing number of viruses, but many important mechanistic details remain to be elucidated. Previously, we demonstrated that pan-retroviral nucleocapsid (NC) and the HIV-1 pr55 Gag (Gag) proteins phase separate into condensates, and that HIV-1 protease (PR)-mediated maturation of Gag and Gag-Pol precursor proteins yield self-assembling BMCs having HIV-1 core architecture. Using biochemical and imaging techniques, we aimed to further characterize the phase separation of HIV-1 Gag by determining which of its intrinsically disordered regions (IDRs) influence the formation of BMCs and how the HIV-1 viral genomic RNA (gRNA) could influence BMC abundance and size. We found that mutations in the Gag matrix (MA) domain or the NC zinc finger motifs altered condensate number and size in a salt-dependent manner. Gag BMCs were also bimodally influenced by the gRNA, with a condensate-promoting regime at lower protein concentrations and a gel dissolution at higher protein concentrations. Interestingly, incubation of Gag with CD4 + T cell nuclear lysates led to the formation of larger BMCs as compared to much smaller ones observed in the presence of cytoplasmic lysates. These findings suggests that the composition and properties of Gag-containing BMCs may be altered by differential association of host factors in nuclear and cytosolic compartments during virus assembly. This study significantly advances our understanding of HIV-1 Gag BMC formation and provides a foundation for future therapeutic targeting of virion assembly.
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19
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Sarthak K, Winogradoff D, Ge Y, Myong S, Aksimentiev A. Benchmarking Molecular Dynamics Force Fields for All-Atom Simulations of Biological Condensates. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.09.527891. [PMID: 36798393 PMCID: PMC9934651 DOI: 10.1101/2023.02.09.527891] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
Proteins containing intrinsically disordered regions are integral components of the cellular signaling pathways and common components of biological condensates. Point mutations in the protein sequence, genetic at birth or acquired through aging, can alter the properties of the condensates, marking the onset of neurodegenerative diseases such as ALS and dementia. While all-atom molecular dynamics method can, in principle, elucidate the conformational changes responsible for the aging of the condensate, the applications of this method to protein condensate systems is conditioned by the availability of molecular force fields that can accurately describe both structured and disordered regions of such proteins. Using the special-purpose Anton 2 supercomputer, we benchmarked the efficacy of nine presently available molecular force fields in describing the structure and dynamics of a Fused in sarcoma (FUS) protein. Five-microsecond simulations of the full-length FUS protein characterized the effect of the force field on the global conformation of the protein, self-interactions among its side chains, solvent accessible surface area and the diffusion constant. Using the results of dynamic light scattering as a benchmark for the FUS radius of gyration, we identified several force field that produced FUS conformations within the experimental range. Next, we used these force fields to perform ten-microsecond simulations of two structured RNA binding domains of FUS bound to their respective RNA targets, finding the choice of the force field to affect stability of the RNA-FUS complex. Taken together, our data suggest that a combination of protein and RNA force fields sharing a common four-point water model provides an optimal description of proteins containing both disordered and structured regions and RNA-protein interactions. To make simulations of such systems available beyond the Anton 2 machines, we describe and validate implementation of the best performing force fields in a publicly available molecular dynamics program NAMD. Our NAMD implementation enables simulations of large (tens of millions of atoms) biological condensate systems and makes such simulations accessible to a broader scientific community. Graphical TOC Entry
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20
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Colombo EA, Valiante M, Uggeri M, Orro A, Majore S, Grammatico P, Gentilini D, Finelli P, Gervasini C, D’Ursi P, Larizza L. Germline NUP98 Variants in Two Siblings with a Rothmund-Thomson-Like Spectrum: Protein Functional Changes Predicted by Molecular Modeling. Int J Mol Sci 2023; 24:4028. [PMID: 36835439 PMCID: PMC9965077 DOI: 10.3390/ijms24044028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 02/08/2023] [Accepted: 02/14/2023] [Indexed: 02/19/2023] Open
Abstract
Two adult siblings born to first-cousin parents presented a clinical phenotype reminiscent of Rothmund-Thomson syndrome (RTS), implying fragile hair, absent eyelashes/eyebrows, bilateral cataracts, mottled pigmentation, dental decay, hypogonadism, and osteoporosis. As the clinical suspicion was not supported by the sequencing of RECQL4, the RTS2-causative gene, whole exome sequencing was applied and disclosed the homozygous variants c.83G>A (p.Gly28Asp) and c.2624A>C (p.Glu875Ala) in the nucleoporin 98 (NUP98) gene. Though both variants affect highly conserved amino acids, the c.83G>A looked more intriguing due to its higher pathogenicity score and location of the replaced amino acid between phenylalanine-glycine (FG) repeats within the first NUP98 intrinsically disordered region. Molecular modeling studies of the mutated NUP98 FG domain evidenced a dispersion of the intramolecular cohesion elements and a more elongated conformational state compared to the wild type. This different dynamic behavior may affect the NUP98 functions as the minor plasticity of the mutated FG domain undermines its role as a multi-docking station for RNA and proteins, and the impaired folding can lead to the weakening or the loss of specific interactions. The clinical overlap of NUP98-mutated and RTS2/RTS1 patients, accounted by converging dysregulated gene networks, supports this first-described constitutional NUP98 disorder, expanding the well-known role of NUP98 in cancer.
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Affiliation(s)
- Elisa Adele Colombo
- Genetica Medica, Dipartimento di Scienze Della Salute, Università Degli Studi di Milano, 20142 Milano, Italy
| | - Michele Valiante
- Laboratory of Medical Genetics, Department of Experimental Medicine, Sapienza University, San Camillo-Forlanini Hospital, 00152 Roma, Italy
| | - Matteo Uggeri
- Department of Biomedical Sciences National Research Council, Institute for Biomedical Technologies, 20054 Segrate, Italy
- Department of Pharmacy, Section of Medicinal Chemistry, School of Medical and Pharmaceutical Sciences, University of Genoa, 16132 Genoa, Italy
| | - Alessandro Orro
- Department of Biomedical Sciences National Research Council, Institute for Biomedical Technologies, 20054 Segrate, Italy
| | - Silvia Majore
- Laboratory of Medical Genetics, Department of Experimental Medicine, Sapienza University, San Camillo-Forlanini Hospital, 00152 Roma, Italy
| | - Paola Grammatico
- Laboratory of Medical Genetics, Department of Experimental Medicine, Sapienza University, San Camillo-Forlanini Hospital, 00152 Roma, Italy
| | - Davide Gentilini
- Bioinformatics and Statistical Genomics Unit, IRCCS Istituto Auxologico Italiano, Via Ariosto 13, 20145 Milan, Italy
- Department of Brain and Behavioral Sciences, University of Pavia, 27100 Pavia, Italy
| | - Palma Finelli
- Experimental Research Laboratory of Medical Cytogenetics and Molecular Genetics, IRCCS Istituto Auxologico Italiano, Via Ariosto 13, 20145 Milan, Italy
- Department of Medical Biotechnology and Translational Medicine, University of Milan, 20133 Milan, Italy
| | - Cristina Gervasini
- Genetica Medica, Dipartimento di Scienze Della Salute, Università Degli Studi di Milano, 20142 Milano, Italy
| | - Pasqualina D’Ursi
- Department of Biomedical Sciences National Research Council, Institute for Biomedical Technologies, 20054 Segrate, Italy
| | - Lidia Larizza
- Experimental Research Laboratory of Medical Cytogenetics and Molecular Genetics, IRCCS Istituto Auxologico Italiano, Via Ariosto 13, 20145 Milan, Italy
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21
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Zheng T, Zilman A. Self-regulation of the nuclear pore complex enables clogging-free crowded transport. Proc Natl Acad Sci U S A 2023; 120:e2212874120. [PMID: 36757893 PMCID: PMC9963888 DOI: 10.1073/pnas.2212874120] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Accepted: 01/05/2023] [Indexed: 02/10/2023] Open
Abstract
Nuclear pore complexes (NPCs) are the main conduits for macromolecular transport into and out of the nucleus of eukaryotic cells. The central component of the NPC transport mechanism is an assembly of intrinsically disordered proteins (IDPs) that fills the NPC channel. The channel interior is further crowded by large numbers of simultaneously translocating cargo-carrying and free transport proteins. How the NPC can efficiently, rapidly, and selectively transport varied cargoes in such crowded conditions remains ill understood. Past experimental results suggest that the NPC is surprisingly resistant to clogging and that transport may even become faster and more efficient as the concentration of transport protein increases. To understand the mechanisms behind these puzzling observations, we construct a computational model of the NPC comprising only a minimal set of commonly accepted consensus features. This model qualitatively reproduces the previous experimental results and identifies self-regulating mechanisms that relieve crowding. We show that some of the crowding-alleviating mechanisms-such as preventing saturation of the bulk flux-are "robust" and rely on very general properties of crowded dynamics in confined channels, pertaining to a broad class of selective transport nanopores. By contrast, the counterintuitive ability of the NPC to leverage crowding to achieve more efficient single-molecule translocation is "fine-tuned" and relies on the particular spatial architecture of the IDP assembly in the NPC channel.
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Affiliation(s)
- Tiantian Zheng
- Department of Physics, University of Toronto, Toronto, ONM5S 1A7, Canada
| | - Anton Zilman
- Department of Physics, University of Toronto, Toronto, ONM5S 1A7, Canada
- Institute for Biomedical Engineering, University of Toronto, Toronto, ONM5S 3G9, Canada
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22
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Ng SC, Biswas A, Huyton T, Schünemann J, Reber S, Görlich D. Barrier properties of Nup98 FG phases ruled by FG motif identity and inter-FG spacer length. Nat Commun 2023; 14:747. [PMID: 36765044 PMCID: PMC9918544 DOI: 10.1038/s41467-023-36331-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Accepted: 01/24/2023] [Indexed: 02/12/2023] Open
Abstract
Nup98 FG repeat domains comprise hydrophobic FG motifs linked through uncharged spacers. FG motifs capture nuclear transport receptors (NTRs) during nuclear pore complex (NPC) passage, confer inter-repeat cohesion, and condense the domains into a selective phase with NPC-typical barrier properties. We show that shortening inter-FG spacers enhances cohesion, increases phase density, and tightens such barrier - all consistent with a sieve-like phase. Phase separation tolerates mutating the Nup98-typical GLFG motifs, provided domain-hydrophobicity remains preserved. NTR-entry, however, is sensitive to (certain) deviations from canonical FG motifs, suggesting co-evolutionary adaptation. Unexpectedly, we observed that arginines promote FG-phase-entry apparently also by hydrophobic interactions/ hydrogen-bonding and not just through cation-π interactions. Although incompatible with NTR·cargo complexes, a YG phase displays remarkable transport selectivity, particularly for engineered GFPNTR-variants. GLFG to FSFG mutations make the FG phase hypercohesive, precluding NTR-entry. Extending spacers relaxes this hypercohesion. Thus, antagonism between cohesion and NTR·FG interactions is key to transport selectivity.
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Affiliation(s)
- Sheung Chun Ng
- Department of Cellular Logistics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Abin Biswas
- Quantitative Biology, IRI Life Sciences, Humboldt-Universität zu Berlin, Berlin, Germany.,Department of Biological Optomechanics, Max Planck Institute for the Science of Light, Erlangen, Germany
| | - Trevor Huyton
- Department of Cellular Logistics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Jürgen Schünemann
- Department of Cellular Logistics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Simone Reber
- Quantitative Biology, IRI Life Sciences, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Dirk Görlich
- Department of Cellular Logistics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany.
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23
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Ehm T, Shinar H, Jacoby G, Meir S, Koren G, Segal Asher M, Korpanty J, Thompson MP, Gianneschi NC, Kozlov MM, Azoulay-Ginsburg S, Amir RJ, Rädler JO, Beck R. Self-Assembly of Tunable Intrinsically Disordered Peptide Amphiphiles. Biomacromolecules 2023; 24:98-108. [PMID: 36469950 PMCID: PMC9832477 DOI: 10.1021/acs.biomac.2c00866] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Intrinsically disordered peptide amphiphiles (IDPAs) present a novel class of synthetic conjugates that consist of short hydrophilic polypeptides anchored to hydrocarbon chains. These hybrid polymer-lipid block constructs spontaneously self-assemble into dispersed nanoscopic aggregates or ordered mesophases in aqueous solution due to hydrophobic interactions. Yet, the possible sequence variations and their influence on the self-assembly structures are vast and have hardly been explored. Here, we measure the nanoscopic self-assembled structures of four IDPA systems that differ by their amino acid sequence. We show that permutations in the charge pattern along the sequence remarkably alter the headgroup conformation and consequently alter the pH-triggered phase transitions between spherical, cylindrical micelles and hexagonal condensed phases. We demonstrate that even a single amino acid mutation is sufficient to tune structural transitions in the condensed IDPA mesophases, while peptide conformations remain unfolded and disordered. Furthermore, alteration of the peptide sequence can render IDPAs to become susceptible to enzymatic cleavage and induce enzymatically activated phase transitions. These results hold great potential for embedding multiple functionalities into lipid nanoparticle delivery systems by incorporating IDPAs with the desired properties.
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Affiliation(s)
- Tamara Ehm
- Raymond
& Beverly Sackler School of Physics & Astronomy, Tel Aviv University, Tel Aviv 6997801, Israel,Faculty
of Physics and Center for NanoScience, Ludwig-Maximilians-Universität, MünchenD-80539, Germany,The
Center for Physics & Chemistry of Living Systems, Tel Aviv University, Tel Aviv 6997801, Israel,The
Center for NanoTechnology & NanoScience, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Hila Shinar
- Raymond
& Beverly Sackler School of Physics & Astronomy, Tel Aviv University, Tel Aviv 6997801, Israel,The
Center for Physics & Chemistry of Living Systems, Tel Aviv University, Tel Aviv 6997801, Israel,The
Center for NanoTechnology & NanoScience, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Guy Jacoby
- Raymond
& Beverly Sackler School of Physics & Astronomy, Tel Aviv University, Tel Aviv 6997801, Israel,The
Center for Physics & Chemistry of Living Systems, Tel Aviv University, Tel Aviv 6997801, Israel,The
Center for NanoTechnology & NanoScience, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Sagi Meir
- Raymond
& Beverly Sackler School of Physics & Astronomy, Tel Aviv University, Tel Aviv 6997801, Israel,The
Center for Physics & Chemistry of Living Systems, Tel Aviv University, Tel Aviv 6997801, Israel,The
Center for NanoTechnology & NanoScience, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Gil Koren
- Raymond
& Beverly Sackler School of Physics & Astronomy, Tel Aviv University, Tel Aviv 6997801, Israel,The
Center for Physics & Chemistry of Living Systems, Tel Aviv University, Tel Aviv 6997801, Israel,The
Center for NanoTechnology & NanoScience, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Merav Segal Asher
- The
Center for NanoTechnology & NanoScience, Tel Aviv University, Tel Aviv 6997801, Israel,Raymond
& Beverly Sackler School of Chemistry, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Joanna Korpanty
- Department
of Chemistry, International Institute for Nanotechnology, Chemistry
of Life Processes Institute, Simpson Querrey Institute, Northwestern University, Evanston, Illinois 60208, United States
| | - Matthew P. Thompson
- Department
of Chemistry, International Institute for Nanotechnology, Chemistry
of Life Processes Institute, Simpson Querrey Institute, Northwestern University, Evanston, Illinois 60208, United States
| | - Nathan C. Gianneschi
- Department
of Chemistry, International Institute for Nanotechnology, Chemistry
of Life Processes Institute, Simpson Querrey Institute, Northwestern University, Evanston, Illinois 60208, United States,Department
of Materials Science & Engineering, Department of Biomedical Engineering
and Department of Pharmacology, Northwestern
University, Evanston, Illinois 60208, United States
| | - Michael M. Kozlov
- The
Center for Physics & Chemistry of Living Systems, Tel Aviv University, Tel Aviv 6997801, Israel,Raymond
& Beverly Sackler School of Medicine, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Salome Azoulay-Ginsburg
- Raymond
& Beverly Sackler School of Chemistry, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Roey J. Amir
- The
Center for Physics & Chemistry of Living Systems, Tel Aviv University, Tel Aviv 6997801, Israel,The
Center for NanoTechnology & NanoScience, Tel Aviv University, Tel Aviv 6997801, Israel,Raymond
& Beverly Sackler School of Chemistry, Tel Aviv University, Tel Aviv 6997801, Israel,The
ADAMA Center for Novel Delivery Systems in Crop Protection, Tel Aviv University, Tel Aviv 6997801, Israel,Email
| | - Joachim O. Rädler
- Faculty
of Physics and Center for NanoScience, Ludwig-Maximilians-Universität, MünchenD-80539, Germany,
| | - Roy Beck
- Raymond
& Beverly Sackler School of Physics & Astronomy, Tel Aviv University, Tel Aviv 6997801, Israel,The
Center for Physics & Chemistry of Living Systems, Tel Aviv University, Tel Aviv 6997801, Israel,The
Center for NanoTechnology & NanoScience, Tel Aviv University, Tel Aviv 6997801, Israel,
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24
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van der Zanden SY, Jongsma MLM, Neefjes ACM, Berlin I, Neefjes J. Maintaining soluble protein homeostasis between nuclear and cytoplasmic compartments across mitosis. Trends Cell Biol 2023; 33:18-29. [PMID: 35778326 DOI: 10.1016/j.tcb.2022.06.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 05/23/2022] [Accepted: 06/06/2022] [Indexed: 12/27/2022]
Abstract
The nuclear envelope (NE) is central to the architecture of eukaryotic cells, both as a physical barrier separating the nucleus from the cytoplasm and as gatekeeper of selective transport between them. However, in open mitosis, the NE fragments to allow for spindle formation and segregation of chromosomes, resulting in intermixing of nuclear and cytoplasmic soluble fractions. Recent studies have shed new light on the mechanisms driving reinstatement of soluble proteome homeostasis following NE reformation in daughter cells. Here, we provide an overview of how mitotic cells confront this challenge to ensure continuity of basic cellular functions across generations and elaborate on the implications for the proteasome - a macromolecular machine that functions in both cytoplasmic and nuclear compartments.
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Affiliation(s)
- Sabina Y van der Zanden
- Department of Cell and Chemical Biology, ONCODE Institute, Leiden University Medical Center LUMC, 2333, ZC, Leiden, The Netherlands
| | - Marlieke L M Jongsma
- Department of Cell and Chemical Biology, ONCODE Institute, Leiden University Medical Center LUMC, 2333, ZC, Leiden, The Netherlands
| | - Anna C M Neefjes
- Department of Cell and Chemical Biology, ONCODE Institute, Leiden University Medical Center LUMC, 2333, ZC, Leiden, The Netherlands
| | - Ilana Berlin
- Department of Cell and Chemical Biology, ONCODE Institute, Leiden University Medical Center LUMC, 2333, ZC, Leiden, The Netherlands.
| | - Jacques Neefjes
- Department of Cell and Chemical Biology, ONCODE Institute, Leiden University Medical Center LUMC, 2333, ZC, Leiden, The Netherlands.
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25
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The biophysics of disordered proteins from the point of view of single-molecule fluorescence spectroscopy. Essays Biochem 2022; 66:875-890. [PMID: 36416865 PMCID: PMC9760427 DOI: 10.1042/ebc20220065] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Revised: 10/10/2022] [Accepted: 10/11/2022] [Indexed: 11/24/2022]
Abstract
Intrinsically disordered proteins (IDPs) and regions (IDRs) have emerged as key players across many biological functions and diseases. Differently from structured proteins, disordered proteins lack stable structure and are particularly sensitive to changes in the surrounding environment. Investigation of disordered ensembles requires new approaches and concepts for quantifying conformations, dynamics, and interactions. Here, we provide a short description of the fundamental biophysical properties of disordered proteins as understood through the lens of single-molecule fluorescence observations. Single-molecule Förster resonance energy transfer (FRET) and fluorescence correlation spectroscopy (FCS) provides an extensive and versatile toolbox for quantifying the characteristics of conformational distributions and the dynamics of disordered proteins across many different solution conditions, both in vitro and in living cells.
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26
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A simple thermodynamic description of phase separation of Nup98 FG domains. Nat Commun 2022; 13:6172. [PMID: 36257947 PMCID: PMC9579204 DOI: 10.1038/s41467-022-33697-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Accepted: 09/28/2022] [Indexed: 12/24/2022] Open
Abstract
The permeability barrier of nuclear pore complexes (NPCs) controls nucleocytoplasmic transport. It retains inert macromolecules but allows facilitated passage of nuclear transport receptors that shuttle cargoes into or out of nuclei. The barrier can be described as a condensed phase assembled from cohesive FG repeat domains, including foremost the charge-depleted FG domain of Nup98. We found that Nup98 FG domains show an LCST-type phase separation, and we provide comprehensive and orthogonal experimental datasets for a quantitative description of this behaviour. A derived thermodynamic model correlates saturation concentration with repeat number, temperature, and ionic strength. It allows estimating the enthalpy, entropy, and ΔG (0.2 kJ/mol, 0.1 kB·T) contributions per repeat to phase separation and inter-repeat cohesion. While changing the cohesion strength strongly impacts the strictness of barrier, these numbers provide boundary conditions for in-depth modelling not only of barrier assembly but also of NPC passage.
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27
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Xiao C, Wu G, Chen P, Gao L, Chen G, Zhang H. Phase separation in epigenetics and cancer stem cells. Front Oncol 2022; 12:922604. [PMID: 36081552 PMCID: PMC9445202 DOI: 10.3389/fonc.2022.922604] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Accepted: 07/25/2022] [Indexed: 12/12/2022] Open
Abstract
Accumulating evidence indicates that liquid–liquid phase separation (LLPS) is the basis of the formation of membrane-less compartments in cells. This biomolecular condensate represented by phase separation may influence epigenetics in cancer stem cells (CSCs), a small subpopulation of cancer cells responding to the initiation, maintenance, metastasis, and therapy resistance of cancer. Understanding the underlying biophysical principles and the specific characteristics of biocondensates would provide insights into the precise blocking of potential tumor targets, thereby fundamentally curbing tumor occurrence, recurrence and metastasis. In this review, we summarized the key phenomenon and experimental detection of phase separation and the possibility of regulating the stemness of CSCs through phase separation. We believe that the mechanism of phase separation in CSCs will open up new avenues for the mystery of tumor formation, and modulating phase separation will be a great strategy for CSC-targeted tumor therapy.
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Affiliation(s)
- Chanchan Xiao
- Department of Microbiology and Immunology, School of Medicine, Jinan University, Guangzhou, China
- Institute of Geriatric Immunology, School of Medicine, Jinan University, Guangzhou, China
- Guangdong-Hongkong-Macao Great Bay Area Geroscience Joint Laboratory (GBGJL), School of Medicine, Jinan University, Guangzhou, China
| | - Guangjie Wu
- Department of Microbiology and Immunology, School of Medicine, Jinan University, Guangzhou, China
- Institute of Geriatric Immunology, School of Medicine, Jinan University, Guangzhou, China
- Guangdong-Hongkong-Macao Great Bay Area Geroscience Joint Laboratory (GBGJL), School of Medicine, Jinan University, Guangzhou, China
| | - Pengfei Chen
- Department of Microbiology and Immunology, School of Medicine, Jinan University, Guangzhou, China
- Institute of Geriatric Immunology, School of Medicine, Jinan University, Guangzhou, China
- Guangdong-Hongkong-Macao Great Bay Area Geroscience Joint Laboratory (GBGJL), School of Medicine, Jinan University, Guangzhou, China
| | - Lijuan Gao
- Department of Microbiology and Immunology, School of Medicine, Jinan University, Guangzhou, China
- Institute of Geriatric Immunology, School of Medicine, Jinan University, Guangzhou, China
- Guangdong-Hongkong-Macao Great Bay Area Geroscience Joint Laboratory (GBGJL), School of Medicine, Jinan University, Guangzhou, China
- *Correspondence: Lijuan Gao, ; Guobing Chen, ; Hongyi Zhang,
| | - Guobing Chen
- Department of Microbiology and Immunology, School of Medicine, Jinan University, Guangzhou, China
- Institute of Geriatric Immunology, School of Medicine, Jinan University, Guangzhou, China
- Guangdong-Hongkong-Macao Great Bay Area Geroscience Joint Laboratory (GBGJL), School of Medicine, Jinan University, Guangzhou, China
- *Correspondence: Lijuan Gao, ; Guobing Chen, ; Hongyi Zhang,
| | - Hongyi Zhang
- Department of Microbiology and Immunology, School of Medicine, Jinan University, Guangzhou, China
- Institute of Geriatric Immunology, School of Medicine, Jinan University, Guangzhou, China
- Guangdong-Hongkong-Macao Great Bay Area Geroscience Joint Laboratory (GBGJL), School of Medicine, Jinan University, Guangzhou, China
- *Correspondence: Lijuan Gao, ; Guobing Chen, ; Hongyi Zhang,
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28
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Mosalaganti S, Obarska-Kosinska A, Siggel M, Taniguchi R, Turoňová B, Zimmerli CE, Buczak K, Schmidt FH, Margiotta E, Mackmull MT, Hagen WJH, Hummer G, Kosinski J, Beck M. AI-based structure prediction empowers integrative structural analysis of human nuclear pores. Science 2022; 376:eabm9506. [PMID: 35679397 DOI: 10.1126/science.abm9506] [Citation(s) in RCA: 142] [Impact Index Per Article: 71.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
INTRODUCTION The eukaryotic nucleus pro-tects the genome and is enclosed by the two membranes of the nuclear envelope. Nuclear pore complexes (NPCs) perforate the nuclear envelope to facilitate nucleocytoplasmic transport. With a molecular weight of ∼120 MDa, the human NPC is one of the larg-est protein complexes. Its ~1000 proteins are taken in multiple copies from a set of about 30 distinct nucleoporins (NUPs). They can be roughly categorized into two classes. Scaf-fold NUPs contain folded domains and form a cylindrical scaffold architecture around a central channel. Intrinsically disordered NUPs line the scaffold and extend into the central channel, where they interact with cargo complexes. The NPC architecture is highly dynamic. It responds to changes in nuclear envelope tension with conforma-tional breathing that manifests in dilation and constriction movements. Elucidating the scaffold architecture, ultimately at atomic resolution, will be important for gaining a more precise understanding of NPC function and dynamics but imposes a substantial chal-lenge for structural biologists. RATIONALE Considerable progress has been made toward this goal by a joint effort in the field. A synergistic combination of complementary approaches has turned out to be critical. In situ structural biology techniques were used to reveal the overall layout of the NPC scaffold that defines the spatial reference for molecular modeling. High-resolution structures of many NUPs were determined in vitro. Proteomic analysis and extensive biochemical work unraveled the interaction network of NUPs. Integra-tive modeling has been used to combine the different types of data, resulting in a rough outline of the NPC scaffold. Previous struc-tural models of the human NPC, however, were patchy and limited in accuracy owing to several challenges: (i) Many of the high-resolution structures of individual NUPs have been solved from distantly related species and, consequently, do not comprehensively cover their human counterparts. (ii) The scaf-fold is interconnected by a set of intrinsically disordered linker NUPs that are not straight-forwardly accessible to common structural biology techniques. (iii) The NPC scaffold intimately embraces the fused inner and outer nuclear membranes in a distinctive topol-ogy and cannot be studied in isolation. (iv) The conformational dynamics of scaffold NUPs limits the resolution achievable in structure determination. RESULTS In this study, we used artificial intelligence (AI)-based prediction to generate an exten-sive repertoire of structural models of human NUPs and their subcomplexes. The resulting models cover various domains and interfaces that so far remained structurally uncharac-terized. Benchmarking against previous and unpublished x-ray and cryo-electron micros-copy structures revealed unprecedented accu-racy. We obtained well-resolved cryo-electron tomographic maps of both the constricted and dilated conformational states of the hu-man NPC. Using integrative modeling, we fit-ted the structural models of individual NUPs into the cryo-electron microscopy maps. We explicitly included several linker NUPs and traced their trajectory through the NPC scaf-fold. We elucidated in great detail how mem-brane-associated and transmembrane NUPs are distributed across the fusion topology of both nuclear membranes. The resulting architectural model increases the structural coverage of the human NPC scaffold by about twofold. We extensively validated our model against both earlier and new experimental data. The completeness of our model has enabled microsecond-long coarse-grained molecular dynamics simulations of the NPC scaffold within an explicit membrane en-vironment and solvent. These simulations reveal that the NPC scaffold prevents the constriction of the otherwise stable double-membrane fusion pore to small diameters in the absence of membrane tension. CONCLUSION Our 70-MDa atomically re-solved model covers >90% of the human NPC scaffold. It captures conforma-tional changes that occur during dilation and constriction. It also reveals the precise anchoring sites for intrinsically disordered NUPs, the identification of which is a prerequisite for a complete and dy-namic model of the NPC. Our study exempli-fies how AI-based structure prediction may accelerate the elucidation of subcellular ar-chitecture at atomic resolution. [Figure: see text].
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Affiliation(s)
- Shyamal Mosalaganti
- Department of Molecular Sociology, Max Planck Institute of Biophysics, 60438 Frankfurt am Main, Germany.,Structural and Computational Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany.,Life Sciences Institute and Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Agnieszka Obarska-Kosinska
- Department of Molecular Sociology, Max Planck Institute of Biophysics, 60438 Frankfurt am Main, Germany.,European Molecular Biology Laboratory Hamburg, 22607 Hamburg, Germany
| | - Marc Siggel
- European Molecular Biology Laboratory Hamburg, 22607 Hamburg, Germany.,Department of Theoretical Biophysics, Max Planck Institute of Biophysics, 60438 Frankfurt am Main, Germany.,Centre for Structural Systems Biology, 22607 Hamburg, Germany
| | - Reiya Taniguchi
- Department of Molecular Sociology, Max Planck Institute of Biophysics, 60438 Frankfurt am Main, Germany.,Structural and Computational Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Beata Turoňová
- Department of Molecular Sociology, Max Planck Institute of Biophysics, 60438 Frankfurt am Main, Germany.,Structural and Computational Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Christian E Zimmerli
- Department of Molecular Sociology, Max Planck Institute of Biophysics, 60438 Frankfurt am Main, Germany.,Structural and Computational Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Katarzyna Buczak
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Florian H Schmidt
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Erica Margiotta
- Department of Molecular Sociology, Max Planck Institute of Biophysics, 60438 Frankfurt am Main, Germany.,Structural and Computational Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Marie-Therese Mackmull
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Wim J H Hagen
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Gerhard Hummer
- Department of Theoretical Biophysics, Max Planck Institute of Biophysics, 60438 Frankfurt am Main, Germany.,Institute of Biophysics, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany
| | - Jan Kosinski
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany.,European Molecular Biology Laboratory Hamburg, 22607 Hamburg, Germany.,Centre for Structural Systems Biology, 22607 Hamburg, Germany
| | - Martin Beck
- Department of Molecular Sociology, Max Planck Institute of Biophysics, 60438 Frankfurt am Main, Germany.,Structural and Computational Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
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29
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Fontana P, Dong Y, Pi X, Tong AB, Hecksel CW, Wang L, Fu TM, Bustamante C, Wu H. Structure of cytoplasmic ring of nuclear pore complex by integrative cryo-EM and AlphaFold. Science 2022; 376:eabm9326. [PMID: 35679401 PMCID: PMC10054137 DOI: 10.1126/science.abm9326] [Citation(s) in RCA: 97] [Impact Index Per Article: 48.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
INTRODUCTION The nuclear pore complex (NPC) is the molecular conduit in the nuclear membrane of eukaryotic cells that regulates import and export of biomolecules between the nucleus and the cytosol, with vertebrate NPCs ~110 to 125 MDa in molecular mass and ~120 nm in diameter. NPCs are organized into four main rings: the cytoplasmic ring (CR) at the cytosolic side, the inner ring and the luminal ring on the plane of the nuclear membrane, and the nuclear ring facing the nucleus. Each ring possesses an approximate eightfold symmetry and is composed of multiple copies of different nucleoporins. NPCs have been implicated in numerous biological processes, and their dysfunctions are associated with a growing number of serious human diseases. However, despite pioneering studies from many groups over the past two decades, we still lack a full understanding of NPCs' organization, dynamics, and complexity. RATIONALE We used the Xenopus laevis oocyte as a model system for the structural characterization because each oocyte possesses a large number of NPC particles that can be visualized on native nuclear membranes without the aid of detergent extraction. We used single-particle cryo-electron microscopy (cryo-EM) analysis on data collected at different stage tilt angles for three-dimensional reconstruction and structure prediction with AlphaFold for model building. RESULTS We reconstructed the CR map of X. laevis NPC at 6.9 and 6.7 Å resolutions for the full CR protomer and a core region, respectively, and predicted the structures of the individual nucleoporins using AlphaFold because no high-resolution models of X. laevis Nups were available. For any ambiguous subunit interactions, we also predicted complex structures, which further guided model fitting of the CR protomer. We placed the nucleoporin or complex structures into the CR density to obtain an almost full CR atomic model, composed of the inner and outer Y-complexes, two copies of Nup205, two copies of the Nup214-Nup88-Nup62 complex, one Nup155, and five copies of Nup358. In particular, we predicted the largest protein in the NPC, Nup358, as having an S-shaped globular domain, a coiled-coil domain, and a largely disordered C-terminal region containing phenylalanine-glycine (FG) repeats previously shown to form a gel-like condensate phase for selective cargo passage. Four of the Nup358 copies clamp around the inner and outer Y-complexes to stabilize the CR, and the fifth Nup358 situates in the center of the cluster of clamps. AlphaFold also predicted a homo-oligomeric, likely specifically pentameric, coiled-coil structure of Nup358 that may provide the avidity for Nup358 recruitment to the NPC and for lowering the threshold for Nup358 condensation in NPC biogenesis. CONCLUSION Our studies offer an example of integrative cryo-EM and structure prediction as a general approach for attaining more precise models of megadalton protein complexes from medium-resolution density maps. The more accurate and almost complete model of the CR presented here expands our understanding of the molecular interactions in the NPC and represents a substantial step forward toward the molecular architecture of a full NPC, with implications for NPC function, biogenesis, and regulation. [Figure: see text].
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Affiliation(s)
- Pietro Fontana
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA.,Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115, USA
| | - Ying Dong
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA.,Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115, USA
| | - Xiong Pi
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA.,Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115, USA
| | - Alexander B Tong
- Jason L. Choy Laboratory of Single-Molecule Biophysics, Institute for Quantitative Biosciences-QB3, and Chemistry Graduate Group, University of California, Berkeley, CA 94720, USA
| | - Corey W Hecksel
- Division of CryoEM and Bioimaging, SSRL, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - Longfei Wang
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA.,Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115, USA
| | - Tian-Min Fu
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA.,Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115, USA.,Department of Biological Chemistry and Pharmacology, Ohio State University, Columbus, OH 43210, USA.,The Ohio State University Comprehensive Cancer Center, Columbus, OH 43210, USA
| | - Carlos Bustamante
- Jason L. Choy Laboratory of Single-Molecule Biophysics, Institute for Quantitative Biosciences-QB3, and Chemistry Graduate Group, University of California, Berkeley, CA 94720, USA.,Departments of Molecular and Cell Biology, Physics, and Chemistry, Howard Hughes Medical Institute, University of California, Berkeley, CA 94720, USA
| | - Hao Wu
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA.,Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115, USA
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30
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Nag N, Sasidharan S, Uversky VN, Saudagar P, Tripathi T. Phase separation of FG-nucleoporins in nuclear pore complexes. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2022; 1869:119205. [PMID: 34995711 DOI: 10.1016/j.bbamcr.2021.119205] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 12/14/2021] [Accepted: 12/23/2021] [Indexed: 12/11/2022]
Abstract
The nuclear envelope (NE) is a bilayer membrane that separates and physically isolates the genetic material from the cytoplasm. Nuclear pore complexes (NPCs) are cylindrical structures embedded in the NE and remain the sole channel of communication between the nucleus and the cytoplasm. The interior of NPCs contains densely packed intrinsically disordered FG-nucleoporins (FG-Nups), consequently forming a permeability barrier. This barrier facilitates the selection and specificity of the cargoes that are imported, exported, or shuttled through the NPCs. Recent studies have revealed that FG-Nups undergo the process of liquid-liquid phase separation into liquid droplets. Moreover, these liquid droplets mimic the permeability barrier observed in the interior of NPCs. This review highlights the phase separation of FG-Nups occurring inside the NPCs rooted in the NE. We discuss the phase separation of FG-Nups and compare the different aspects contributing to their phase separation. Furthermore, several diseases caused by the aberrant phase separation of the proteins are examined with respect to NEs. By understanding the fundamental process of phase separation at the nuclear membrane, the review seeks to explore the parameters influencing this phenomenon as well as its importance, ultimately paving the way for better research on the structure-function relationship of biomolecular condensates.
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Affiliation(s)
- Niharika Nag
- Molecular and Structural Biophysics Laboratory, Department of Biochemistry, North-Eastern Hill University, Shillong 793022, India
| | - Santanu Sasidharan
- Department of Biotechnology, National Institute of Technology Warangal, Warangal 506004, India
| | - Vladimir N Uversky
- Department of Molecular Medicine and Byrd Alzheimer's Research Institute, Morsani College of Medicine, University of South Florida, Tampa, FL 33620, United States; Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Institutskiy pereulok, 9, Dolgoprudny, Moscow Region 141700, Russia
| | - Prakash Saudagar
- Department of Biotechnology, National Institute of Technology Warangal, Warangal 506004, India.
| | - Timir Tripathi
- Molecular and Structural Biophysics Laboratory, Department of Biochemistry, North-Eastern Hill University, Shillong 793022, India.
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31
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Matsuda A, Mofrad MRK. On the nuclear pore complex and its emerging role in cellular mechanotransduction. APL Bioeng 2022; 6:011504. [PMID: 35308827 PMCID: PMC8916845 DOI: 10.1063/5.0080480] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 02/21/2022] [Indexed: 12/13/2022] Open
Abstract
The nuclear pore complex (NPC) is a large protein assembly that perforates the nuclear envelope and provides a sole gateway for traffic between the cytoplasm and the nucleus. The NPC controls the nucleocytoplasmic transport by selectively allowing cargoes such as proteins and mRNA to pass through its central channel, thereby playing a vital role in protecting the nuclear component and regulating gene expression and protein synthesis. The selective transport through the NPC originates from its exquisite molecular structure featuring a large scaffold and the intrinsically disordered central channel domain, but the exact mechanism underlying the selective transport remains elusive and is the subject of various, often conflicting, hypotheses. Moreover, recent studies have suggested a new role for the NPC as a mechanosensor, where the NPC changes its channel diameter depending on the nuclear envelope tension, altering the molecular transportability through this nanopore. In this mini-review, we summarize the current understandings of the selective nature of the NPC and discuss its emerging role in cellular mechanotransduction.
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Affiliation(s)
- Atsushi Matsuda
- Molecular Cell Biomechanics Laboratory, Departments of Bioengineering and Mechanical Engineering, University of California Berkeley, Berkeley, California 94720, USA
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32
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Cibulka J, Bisaccia F, Radisavljević K, Gudino Carrillo RM, Köhler A. Assembly principle of a membrane-anchored nuclear pore basket scaffold. SCIENCE ADVANCES 2022; 8:eabl6863. [PMID: 35148185 PMCID: PMC8836807 DOI: 10.1126/sciadv.abl6863] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Nuclear pore complexes (NPCs) are membrane-embedded gatekeepers of traffic between the nucleus and cytoplasm. Key features of the NPC symmetric core have been elucidated, but little is known about the NPC basket, a prominent structure with numerous roles in gene expression. Studying the basket was hampered by its instability and connection to the inner nuclear membrane (INM). Here, we reveal the assembly principle of the yeast NPC basket by reconstituting a recombinant Nup60-Mlp1-Nup2 scaffold on a synthetic membrane. Nup60 serves as the basket's flexible suspension cable, harboring an array of short linear motifs (SLiMs). These bind multivalently to the INM, the coiled-coil protein Mlp1, the FG-nucleoporin Nup2, and the NPC core. We suggest that SLiMs, embedded in disordered regions, allow the basket to adapt its structure in response to bulky cargo and changes in gene expression. Our study opens avenues for the higher-order reconstitution of basket-anchored NPC assemblies on membranes.
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33
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Musacchio A. On the role of phase separation in the biogenesis of membraneless compartments. EMBO J 2022; 41:e109952. [PMID: 35107832 PMCID: PMC8886532 DOI: 10.15252/embj.2021109952] [Citation(s) in RCA: 99] [Impact Index Per Article: 49.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 01/07/2022] [Accepted: 01/10/2022] [Indexed: 12/16/2022] Open
Abstract
Molecular mechanistic biology has ushered us into the world of life’s building blocks, revealing their interactions in macromolecular complexes and inspiring strategies for detailed functional interrogations. The biogenesis of membraneless cellular compartments, functional mesoscale subcellular locales devoid of strong internal order and delimiting membranes, is among mechanistic biology’s most demanding current challenges. A developing paradigm, biomolecular phase separation, emphasizes solvation of the building blocks through low‐affinity, weakly adhesive unspecific interactions as the driver of biogenesis of membraneless compartments. Here, I discuss the molecular underpinnings of the phase separation paradigm and demonstrate that validating its assumptions is much more challenging than hitherto appreciated. I also discuss that highly specific interactions, rather than unspecific ones, appear to be the main driver of biogenesis of subcellular compartments, while phase separation may be harnessed locally in selected instances to generate material properties tailored for specific functions, as exemplified by nucleocytoplasmic transport.
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Affiliation(s)
- Andrea Musacchio
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Dortmund, Germany
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34
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Medvedev KE, Pei J, Grishin NV. DisEnrich: database of enriched regions in human dark proteome. Bioinformatics 2022; 38:1870-1876. [PMID: 35094056 PMCID: PMC8963327 DOI: 10.1093/bioinformatics/btac051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 12/22/2021] [Accepted: 01/25/2022] [Indexed: 02/01/2023] Open
Abstract
MOTIVATION Intrinsically disordered proteins (IDPs) are involved in numerous processes crucial for living organisms. Bias in amino acid composition of these proteins determines their unique biophysical and functional features. Distinct intrinsically disordered regions (IDRs) with compositional bias play different important roles in various biological processes. IDRs enriched in particular amino acids in human proteome have not been described consistently. RESULTS We developed DisEnrich-the database of human proteome IDRs that are significantly enriched in particular amino acids. Each human protein is described using Gene Ontology (GO) function terms, disorder prediction for the full-length sequence using three methods, enriched IDR composition and ranks of human proteins with similar enriched IDRs. Distribution analysis of enriched IDRs among broad functional categories revealed significant overrepresentation of R- and Y-enriched IDRs in metabolic and enzymatic activities and F-enriched IDRs in transport. About 75% of functional categories contain IDPs with IDRs significantly enriched in hydrophobic residues that are important for protein-protein interactions. AVAILABILITY AND IMPLEMENTATION The database is available at http://prodata.swmed.edu/DisEnrichDB/. SUPPLEMENTARY INFORMATION Supplementary data are available at Bioinformatics Advances online.
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Affiliation(s)
| | - Jimin Pei
- McDermott Center for Human Growth and Development, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Nick V Grishin
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA,Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA,Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
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35
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Michels JJ, Brzezinski M, Scheidt T, Lemke EA, Parekh SH. Role of Solvent Compatibility in the Phase Behavior of Binary Solutions of Weakly Associating Multivalent Polymers. Biomacromolecules 2022; 23:349-364. [PMID: 34866377 PMCID: PMC8753604 DOI: 10.1021/acs.biomac.1c01301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 11/23/2021] [Indexed: 11/29/2022]
Abstract
Condensate formation of biopolymer solutions, prominently those of various intrinsically disordered proteins (IDPs), is often driven by "sticky" interactions between associating residues, multivalently present along the polymer backbone. Using a ternary mean-field "stickers-and-spacers" model, we demonstrate that if sticker association is of the order of a few times the thermal energy, a delicate balance between specific binding and nonspecific polymer-solvent interactions gives rise to a particularly rich ternary phase behavior under physiological circumstances. For a generic system represented by a solution comprising multiassociative scaffold and client polymers, the difference in solvent compatibility between the polymers modulates the nature of isothermal liquid-liquid phase separation (LLPS) between associative and segregative. The calculations reveal regimes of dualistic phase behavior, where both types of LLPS occur within the same phase diagram, either associated with the presence of multiple miscibility gaps or a flip in the slope of the tie-lines belonging to a single coexistence region.
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Affiliation(s)
- Jasper J. Michels
- Max
Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Mateusz Brzezinski
- Max
Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Tom Scheidt
- Institute
for Molecular Biology, Johannes Gutenberg
University, Ackermannweg
4, 55128 Mainz, Germany
| | - Edward A. Lemke
- Institute
for Molecular Biology, Johannes Gutenberg
University, Ackermannweg
4, 55128 Mainz, Germany
| | - Sapun H. Parekh
- Max
Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
- Department
of Biomedical Engineering, The University
of Texas at Austin, 107
West Dean Keeton Street Stop C0800, Austin, Texas 78712, United States
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36
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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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37
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Rai SK, Savastano A, Singh P, Mukhopadhyay S, Zweckstetter M. Liquid-liquid phase separation of tau: From molecular biophysics to physiology and disease. Protein Sci 2021; 30:1294-1314. [PMID: 33930220 PMCID: PMC8197432 DOI: 10.1002/pro.4093] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Revised: 04/24/2021] [Accepted: 04/27/2021] [Indexed: 12/14/2022]
Abstract
Biomolecular condensation via liquid-liquid phase separation (LLPS) of intrinsically disordered proteins/regions (IDPs/IDRs), with and without nucleic acids, has drawn widespread interest due to the rapidly unfolding role of phase-separated condensates in a diverse range of cellular functions and human diseases. Biomolecular condensates form via transient and multivalent intermolecular forces that sequester proteins and nucleic acids into liquid-like membrane-less compartments. However, aberrant phase transitions into gel-like or solid-like aggregates might play an important role in neurodegenerative and other diseases. Tau, a microtubule-associated neuronal IDP, is involved in microtubule stabilization, regulates axonal outgrowth and transport in neurons. A growing body of evidence indicates that tau can accomplish some of its cellular activities via LLPS. However, liquid-to-solid transition resulting in the abnormal aggregation of tau is associated with neurodegenerative diseases. The physical chemistry of tau is crucial for governing its propensity for biomolecular condensation which is governed by various intermolecular and intramolecular interactions leading to simple one-component and complex multi-component condensates. In this review, we aim at capturing the current scientific state in unveiling the intriguing molecular mechanism of phase separation of tau. We particularly focus on the amalgamation of existing and emerging biophysical tools that offer unique spatiotemporal resolutions on a wide range of length- and time-scales. We also discuss the link between quantitative biophysical measurements and novel biological insights into biomolecular condensation of tau. We believe that this account will provide a broad and multidisciplinary view of phase separation of tau and its association with physiology and disease.
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Affiliation(s)
- Sandeep K. Rai
- Centre for Protein Science, Design and Engineering, Department of Biological Sciences, and Department of Chemical SciencesIndian Institute of Science Education and Research (IISER)MohaliIndia
| | - Adriana Savastano
- Research group Translational Structural BiologyGerman Center for Neurodegenerative Diseases (DZNE)GöttingenGermany
| | - Priyanka Singh
- Centre for Protein Science, Design and Engineering, Department of Biological Sciences, and Department of Chemical SciencesIndian Institute of Science Education and Research (IISER)MohaliIndia
| | - Samrat Mukhopadhyay
- Centre for Protein Science, Design and Engineering, Department of Biological Sciences, and Department of Chemical SciencesIndian Institute of Science Education and Research (IISER)MohaliIndia
| | - Markus Zweckstetter
- Research group Translational Structural BiologyGerman Center for Neurodegenerative Diseases (DZNE)GöttingenGermany
- Department for NMR‐based Structural BiologyMax Planck Institute for Biophysical ChemistryGöttingenGermany
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38
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Ng SC, Güttler T, Görlich D. Recapitulation of selective nuclear import and export with a perfectly repeated 12mer GLFG peptide. Nat Commun 2021; 12:4047. [PMID: 34193851 PMCID: PMC8245513 DOI: 10.1038/s41467-021-24292-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Accepted: 06/11/2021] [Indexed: 12/04/2022] Open
Abstract
The permeability barrier of nuclear pore complexes (NPCs) controls nucleocytoplasmic transport. It retains inert macromolecules while allowing facilitated passage of importins and exportins, which in turn shuttle cargo into or out of cell nuclei. The barrier can be described as a condensed phase assembled from cohesive FG repeat domains. NPCs contain several distinct FG domains, each comprising variable repeats. Nevertheless, we now found that sequence heterogeneity is no fundamental requirement for barrier function. Instead, we succeeded in engineering a perfectly repeated 12mer GLFG peptide that self-assembles into a barrier of exquisite transport selectivity and fast transport kinetics. This barrier recapitulates RanGTPase-controlled importin- and exportin-mediated cargo transport and thus represents an ultimately simplified experimental model system. An alternative proline-free sequence forms an amyloid FG phase. Finally, we discovered that FG phases stain bright with ‘DNA-specific’ DAPI/ Hoechst probes, and that such dyes allow for a photo-induced block of nuclear transport. The permeability barrier of nuclear pore complexes blocks passage of inert macromolecules but allows rapid, receptor-mediated, and RanGTPase-driven transport of cargoes up to ribosome size. The authors now show that such a barrier can be faithfully recapitulated by an ultimately simplified FG phase assembled solely from a tandemly repeated 12mer GLFG peptide.
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Affiliation(s)
- Sheung Chun Ng
- Department of Cellular Logistics, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Thomas Güttler
- Department of Cellular Logistics, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Dirk Görlich
- Department of Cellular Logistics, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany.
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39
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Yoshizawa T, Guo L. Karyopherin-βs play a key role as a phase separation regulator. J Biochem 2021; 170:15-23. [PMID: 34223614 DOI: 10.1093/jb/mvab072] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 06/08/2021] [Indexed: 11/13/2022] Open
Abstract
Recent studies have revealed that cells utilize liquid-liquid phase separation (LLPS) as a mechanism in assembly of membrane-less organelles, such as RNP granules. The nucleus is a well-known membrane-bound organelle surrounded by the nuclear envelope; the nuclear pore complex on the nuclear envelope likely applies LLPS in the central channel to facilitate selective biological macromolecule exchange. Karyopherin-β family proteins exclusively pass through the central channel with cargos by dissolving the phase separated hydrogel formed by the phenylalanine-glycine (FG) repeats-containing nucleoporins. Karyopherin-βs also exhibit dissolution activity for the phase separation of cargo proteins. Many cargos, including RNA-binding proteins containing intrinsically disordered regions (IDRs), undergo phase separation; however, aberrant phase separation is linked to fatal neurodegenerative diseases. Multiple weak interactions between karyopherin-βs and phase separation-prone proteins, such as FG repeats-containing nucleoporins or IDR-containing karyopherin-β cargos, are likely to be important for passing through the nuclear pore complex and maintaining the soluble state of cargo, respectively. In this review, we discuss how karyopherin-βs regulate phase separation to function.
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Affiliation(s)
- Takuya Yoshizawa
- Department of Biotechnology, College of Life Sciences, Ritsumeikan University, 1-1-1 Noji-Higashi, Kusatsu-shi, Shiga 525-8577, Japan
| | - Lin Guo
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, 1020 Locust St, Philadelphia, PA 19107, USA
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40
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Ding B, Sepehrimanesh M. Nucleocytoplasmic Transport: Regulatory Mechanisms and the Implications in Neurodegeneration. Int J Mol Sci 2021; 22:4165. [PMID: 33920577 PMCID: PMC8072611 DOI: 10.3390/ijms22084165] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2021] [Revised: 04/13/2021] [Accepted: 04/15/2021] [Indexed: 12/12/2022] Open
Abstract
Nucleocytoplasmic transport (NCT) across the nuclear envelope is precisely regulated in eukaryotic cells, and it plays critical roles in maintenance of cellular homeostasis. Accumulating evidence has demonstrated that dysregulations of NCT are implicated in aging and age-related neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS), frontotemporal dementia (FTD), Alzheimer's disease (AD), and Huntington disease (HD). This is an emerging research field. The molecular mechanisms underlying impaired NCT and the pathogenesis leading to neurodegeneration are not clear. In this review, we comprehensively described the components of NCT machinery, including nuclear envelope (NE), nuclear pore complex (NPC), importins and exportins, RanGTPase and its regulators, and the regulatory mechanisms of nuclear transport of both protein and transcript cargos. Additionally, we discussed the possible molecular mechanisms of impaired NCT underlying aging and neurodegenerative diseases, such as ALS/FTD, HD, and AD.
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Affiliation(s)
- Baojin Ding
- Department of Biology, University of Louisiana at Lafayette, 410 East Saint Mary Boulevard, Lafayette, LA 70503, USA;
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41
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Kalita J, Kapinos LE, Lim RYH. On the asymmetric partitioning of nucleocytoplasmic transport - recent insights and open questions. J Cell Sci 2021; 134:239102. [PMID: 33912945 DOI: 10.1242/jcs.240382] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Macromolecular cargoes are asymmetrically partitioned in the nucleus or cytoplasm by nucleocytoplasmic transport (NCT). At the center of this activity lies the nuclear pore complex (NPC), through which soluble factors circulate to orchestrate NCT. These include cargo-carrying importin and exportin receptors from the β-karyopherin (Kapβ) family and the small GTPase Ran, which switches between guanosine triphosphate (GTP)- and guanosine diphosphate (GDP)-bound forms to regulate cargo delivery and compartmentalization. Ongoing efforts have shed considerable light on how these soluble factors traverse the NPC permeability barrier to sustain NCT. However, this does not explain how importins and exportins are partitioned in the cytoplasm and nucleus, respectively, nor how a steep RanGTP-RanGDP gradient is maintained across the nuclear envelope. In this Review, we peel away the multiple layers of control that regulate NCT and juxtapose unresolved features against known aspects of NPC function. Finally, we discuss how NPCs might function synergistically with Kapβs, cargoes and Ran to establish the asymmetry of NCT.
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Affiliation(s)
- Joanna Kalita
- Biozentrum and the Swiss Nanoscience Institute, University of Basel, Basel CH4056, Switzerland
| | - Larisa E Kapinos
- Biozentrum and the Swiss Nanoscience Institute, University of Basel, Basel CH4056, Switzerland
| | - Roderick Y H Lim
- Biozentrum and the Swiss Nanoscience Institute, University of Basel, Basel CH4056, Switzerland
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42
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Biesaga M, Frigolé-Vivas M, Salvatella X. Intrinsically disordered proteins and biomolecular condensates as drug targets. Curr Opin Chem Biol 2021; 62:90-100. [PMID: 33812316 DOI: 10.1016/j.cbpa.2021.02.009] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 02/14/2021] [Accepted: 02/21/2021] [Indexed: 11/16/2022]
Abstract
Intrinsically disordered domains represent attractive therapeutic targets because they play key roles in cancer, as well as in neurodegenerative and infectious diseases. They are, however, considered undruggable because they do not form stable binding pockets for small molecules and, therefore, have not been prioritized in drug discovery. Under physiological solution conditions many biomedically relevant intrinsically disordered proteins undergo phase separation processes leading to the formation of mesoscopic highly dynamic assemblies, generally known as biomolecular condensates that define environments that can be quite different from the solutions surrounding them. In what follows, we review key recent findings in this area and show how biomolecular condensation can offer opportunities for modulating the activities of intrinsically disordered targets.
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Affiliation(s)
- Mateusz Biesaga
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Baldiri Reixac 10, 08028, Barcelona, Spain; Joint BSC-IRB Research Programme in Computational Biology, Baldiri Reixac 10, 08028, Barcelona, Spain
| | - Marta Frigolé-Vivas
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Baldiri Reixac 10, 08028, Barcelona, Spain; Joint BSC-IRB Research Programme in Computational Biology, Baldiri Reixac 10, 08028, Barcelona, Spain
| | - Xavier Salvatella
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Baldiri Reixac 10, 08028, Barcelona, Spain; Joint BSC-IRB Research Programme in Computational Biology, Baldiri Reixac 10, 08028, Barcelona, Spain; ICREA, Passeig Lluís Companys 23, 08010, Barcelona, Spain.
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43
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One Ring to Rule them All? Structural and Functional Diversity in the Nuclear Pore Complex. Trends Biochem Sci 2021; 46:595-607. [PMID: 33563541 DOI: 10.1016/j.tibs.2021.01.003] [Citation(s) in RCA: 55] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2020] [Revised: 01/05/2021] [Accepted: 01/11/2021] [Indexed: 02/07/2023]
Abstract
The nuclear pore complex (NPC) is the massive protein assembly that regulates the transport of macromolecules between the nucleus and the cytoplasm. Recent breakthroughs have provided major insights into the structure of the NPC in different eukaryotes, revealing a previously unsuspected diversity of NPC architectures. In parallel, the NPC has been shown to be a key player in regulating essential nuclear processes such as chromatin organization, gene expression, and DNA repair. However, our knowledge of the NPC structure has not been able to address the molecular mechanisms underlying its regulatory roles. We discuss potential explanations, including the coexistence of alternative NPC architectures with specific functional roles.
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44
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Paci G, Caria J, Lemke EA. Cargo transport through the nuclear pore complex at a glance. J Cell Sci 2021; 134:237315. [PMID: 33495357 DOI: 10.1242/jcs.247874] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Bidirectional transport of macromolecules across the nuclear envelope is a hallmark of eukaryotic cells, in which the genetic material is compartmentalized inside the nucleus. The nuclear pore complex (NPC) is the major gateway to the nucleus and it regulates nucleocytoplasmic transport, which is key to processes including transcriptional regulation and cell cycle control. Accordingly, components of the nuclear transport machinery are often found to be dysregulated or hijacked in diseases. In this Cell Science at a Glance article and accompanying poster, we provide an overview of our current understanding of cargo transport through the NPC, from the basic transport signals and machinery to more emerging aspects, all from a 'cargo perspective'. Among these, we discuss the transport of large cargoes (>15 nm), as well as the roles of different cargo properties to nuclear transport, from size and number of bound nuclear transport receptors (NTRs), to surface and mechanical properties.
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Affiliation(s)
- Giulia Paci
- Biocentre, Johannes Gutenberg-University Mainz, Hans-Dieter-Hüsch-Weg 15, 555128 Mainz, Germany.,Institute of Molecular Biology, Ackermannweg 4, 55128 Mainz, Germany.,European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Joana Caria
- Biocentre, Johannes Gutenberg-University Mainz, Hans-Dieter-Hüsch-Weg 15, 555128 Mainz, Germany.,Institute of Molecular Biology, Ackermannweg 4, 55128 Mainz, Germany.,European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Edward A Lemke
- Biocentre, Johannes Gutenberg-University Mainz, Hans-Dieter-Hüsch-Weg 15, 555128 Mainz, Germany .,Institute of Molecular Biology, Ackermannweg 4, 55128 Mainz, Germany.,European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany
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45
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Vishnoi N, Dhanasekeran K, Chalfant M, Surovstev I, Khokha MK, Lusk CP. Differential turnover of Nup188 controls its levels at centrosomes and role in centriole duplication. J Cell Biol 2020; 219:133835. [PMID: 32211895 PMCID: PMC7055002 DOI: 10.1083/jcb.201906031] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Revised: 11/18/2019] [Accepted: 01/09/2020] [Indexed: 02/07/2023] Open
Abstract
NUP188 encodes a scaffold component of the nuclear pore complex (NPC) and has been implicated as a congenital heart disease gene through an ill-defined function at centrioles. Here, we explore the mechanisms that physically and functionally segregate Nup188 between the pericentriolar material (PCM) and NPCs. Pulse-chase fluorescent labeling indicates that Nup188 populates centrosomes with newly synthesized protein that does not exchange with NPCs even after mitotic NPC breakdown. In addition, the steady-state levels of Nup188 are controlled by the sensitivity of the PCM pool, but not the NPC pool, to proteasomal degradation. Proximity-labeling and super-resolution microscopy show that Nup188 is vicinal to the inner core of the interphase centrosome. Consistent with this, we demonstrate direct binding between Nup188 and Cep152. We further show that Nup188 functions in centriole duplication at or upstream of Sas6 loading. Together, our data establish Nup188 as a component of PCM needed to duplicate the centriole with implications for congenital heart disease mechanisms.
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Affiliation(s)
- Nidhi Vishnoi
- Department of Cell Biology, Yale School of Medicine, New Haven, CT
| | | | | | - Ivan Surovstev
- Department of Cell Biology, Yale School of Medicine, New Haven, CT
| | - Mustafa K Khokha
- Pediatric Genomics Discovery Program, Departments of Pediatrics and Genetics, Yale School of Medicine, New Haven, CT
| | - C Patrick Lusk
- Department of Cell Biology, Yale School of Medicine, New Haven, CT
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46
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Diez L, Wegmann S. Nuclear Transport Deficits in Tau-Related Neurodegenerative Diseases. Front Neurol 2020; 11:1056. [PMID: 33101165 PMCID: PMC7546323 DOI: 10.3389/fneur.2020.01056] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Accepted: 08/11/2020] [Indexed: 12/14/2022] Open
Abstract
Tau is a cytosolic microtubule binding protein that is highly abundant in the axons of the central nervous system. However, alternative functions of tau also in other cellular compartments are suggested, for example, in the nucleus, where interactions of tau with specific nuclear entities such as DNA, the nucleolus, and the nuclear envelope have been reported. We would like to review the current knowledge about tau-nucleus interactions and lay out possible neurotoxic mechanisms that are based on the (pathological) interactions of tau with the nucleus.
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Affiliation(s)
- Lisa Diez
- German Center for Neurodegenerative Diseases, Berlin, Germany
| | - Susanne Wegmann
- German Center for Neurodegenerative Diseases, Berlin, Germany
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47
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Phase Separation in Membrane Biology: The Interplay between Membrane-Bound Organelles and Membraneless Condensates. Dev Cell 2020; 55:30-44. [PMID: 32726575 DOI: 10.1016/j.devcel.2020.06.033] [Citation(s) in RCA: 156] [Impact Index Per Article: 39.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 06/14/2020] [Accepted: 06/26/2020] [Indexed: 12/13/2022]
Abstract
In eukaryotic cells, various membrane-bound organelles compartmentalize diverse cellular activities in a spatially and temporally controlled manner. Numerous membraneless organelles assembled via liquid-liquid phase separation (LLPS), known as condensates, also facilitate compartmentalization of cellular functions. Emerging evidence shows that these two organelle types interact in many biological processes. Membranes modulate the biogenesis and dynamics of phase-separated condensates by serving as assembly platforms or by forming direct contacts. Phase separation of membrane-associated proteins participates in various trafficking events, such as clustering of vesicles for temporally controlled fusion and storage, and transport of membraneless condensates on membrane-bound organelles. Phase separation also acts in cargo trafficking pathways by sorting and docking cargos for translocon-mediated transport across membranes, by shuttling cargos through the nuclear pore complex, and by triggering the formation of surrounding autophagosomes for delivery to lysosomes. The coordinated actions of membrane-bound and membraneless organelles ensure spatiotemporal control of various cellular functions.
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48
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Uzdensky AB. Multifunctional Proteins. Biophysics (Nagoya-shi) 2020. [DOI: 10.1134/s0006350920030227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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49
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Ding B, Akter M, Zhang CL. Differential Influence of Sample Sex and Neuronal Maturation on mRNA and Protein Transport in Induced Human Neurons. Front Mol Neurosci 2020; 13:46. [PMID: 32317929 PMCID: PMC7146707 DOI: 10.3389/fnmol.2020.00046] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Accepted: 03/06/2020] [Indexed: 12/11/2022] Open
Abstract
Nucleocytoplasmic transport (NCT) across thenuclear envelope (NE) is tightly regulated in eukaryotic cells and iscritical for maintaining cellular homeostasis. Its dysregulationleads to aging and neurodegeneration. Because they maintainaging-associated hallmarks, directly reprogrammed neurons from human fibroblasts are invaluable in understanding NCT. However, it is not clear whether NCT activity is influenced by neuronal maturation and sample sex [a key biological variable emphasized by the National Institutes of Health (NIH) policy]. We examined here NCT activity at the single-cell level by measuring mRNA subcellular distribution and protein transport in directly induced motor neurons (diMNs) from adult human fibroblasts. The results show that mRNA subcellular distribution but not protein transport is affected by neuronal maturation stages, whereas both transport processes are not influenced by the sample sex. This study also provides quantitative methods and optimized conditions for measuring NCTs of mRNAs or protein cargoes, establishing a robust way for future functional examinations of NCT activity in directly induced neurons from diseased human patients.
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Affiliation(s)
- Baojin Ding
- Department of Biology, University of Louisiana at Lafayette, Lafayette, LA, United States
| | - Masuma Akter
- Department of Biology, University of Louisiana at Lafayette, Lafayette, LA, United States
| | - Chun-Li Zhang
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX, United States.,Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX, United States
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50
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Fallini C, Khalil B, Smith CL, Rossoll W. Traffic jam at the nuclear pore: All roads lead to nucleocytoplasmic transport defects in ALS/FTD. Neurobiol Dis 2020; 140:104835. [PMID: 32179176 DOI: 10.1016/j.nbd.2020.104835] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Revised: 01/25/2020] [Accepted: 03/12/2020] [Indexed: 02/06/2023] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal late-onset neurodegenerative disease that specifically affects the function and survival of spinal and cortical motor neurons. ALS shares many genetic, clinical, and pathological characteristics with frontotemporal dementia (FTD), and these diseases are now recognized as presentations of a disease spectrum known as ALS/FTD. The molecular determinants of neuronal loss in ALS/FTD are still debated, but the recent discovery of nucleocytoplasmic transport defects as a common denominator of most if not all forms of ALS/FTD has dramatically changed our understanding of the pathogenic mechanisms of this disease. Loss of nuclear pores and nucleoporin aggregation, altered nuclear morphology, and impaired nuclear transport are some of the most prominent features that have been identified using a variety of animal, cellular, and human models of disease. Here, we review the experimental evidence linking nucleocytoplasmic transport defects to the pathogenesis of ALS/FTD and propose a unifying view on how these defects may lead to a vicious cycle that eventually causes neuronal death.
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Affiliation(s)
- Claudia Fallini
- George and Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, RI 02881, USA; Department of Cell and Molecular Biology, University of Rhode Island, Kingston, RI 02881, USA; Department of Biomedical and Pharmaceutical Sciences, University of Rhode Island, Kingston, RI 02881, USA.
| | - Bilal Khalil
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Courtney L Smith
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Wilfried Rossoll
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA.
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