1
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Jafarinia H, van der Giessen E, Onck PR. C9orf72 polyPR directly binds to various nuclear transport components. eLife 2024; 12:RP89694. [PMID: 38483313 PMCID: PMC10939497 DOI: 10.7554/elife.89694] [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] [Indexed: 03/17/2024] Open
Abstract
The disruption of nucleocytoplasmic transport (NCT) is an important mechanism in neurodegenerative diseases. In the case of C9orf72-ALS, trafficking of macromolecules through the nuclear pore complex (NPC) might get frustrated by the binding of C9orf72-translated arginine-containing dipeptide repeat proteins (R-DPRs) to the Kapβ family of nuclear transport receptors. Besides Kapβs, several other types of transport components have been linked to NCT impairments in R-DPR-expressed cells, but the molecular origin of these observations has not been clarified. Here, we adopt a coarse-grained molecular dynamics model at amino acid resolution to study the direct interaction between polyPR, the most toxic DPR, and various nuclear transport components to elucidate the binding mechanisms and provide a complete picture of potential polyPR-mediated NCT defects. We found polyPR to directly bind to several isoforms of the Impα family, CAS (the specific exporter of Impα) and RanGAP. We observe no binding between polyPR and Ran. Longer polyPRs at lower salt concentrations also make contact with RanGEF and NTF2. Analyzing the polyPR contact sites on the transport components reveals that polyPR potentially interferes with RanGTP/RanGDP binding, with nuclear localization signal (NLS)-containing cargoes (cargo-NLS) binding to Impα, with cargo-NLS release from Impα, and with Impα export from the nucleus. The abundance of polyPR-binding sites on multiple transport components combined with the inherent polyPR length dependence makes direct polyPR interference of NCT a potential mechanistic pathway of C9orf72 toxicity.
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Affiliation(s)
- Hamidreza Jafarinia
- Zernike Institute for Advanced Materials, University of GroningenGroningenNetherlands
| | - Erik van der Giessen
- Zernike Institute for Advanced Materials, University of GroningenGroningenNetherlands
| | - Patrick R Onck
- Zernike Institute for Advanced Materials, University of GroningenGroningenNetherlands
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2
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Klughammer N, Barth A, Dekker M, Fragasso A, Onck PR, Dekker C. Diameter dependence of transport through nuclear pore complex mimics studied using optical nanopores. eLife 2024; 12:RP87174. [PMID: 38376900 PMCID: PMC10942607 DOI: 10.7554/elife.87174] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2024] Open
Abstract
The nuclear pore complex (NPC) regulates the selective transport of large biomolecules through the nuclear envelope. As a model system for nuclear transport, we construct NPC mimics by functionalizing the pore walls of freestanding palladium zero-mode waveguides with the FG-nucleoporin Nsp1. This approach enables the measurement of single-molecule translocations through individual pores using optical detection. We probe the selectivity of Nsp1-coated pores by quantitatively comparing the translocation rates of the nuclear transport receptor Kap95 to the inert probe BSA over a wide range of pore sizes from 35 nm to 160 nm. Pores below 55 ± 5 nm show significant selectivity that gradually decreases for larger pores. This finding is corroborated by coarse-grained molecular dynamics simulations of the Nsp1 mesh within the pore, which suggest that leakage of BSA occurs by diffusion through transient openings within the dynamic mesh. Furthermore, we experimentally observe a modulation of the BSA permeation when varying the concentration of Kap95. The results demonstrate the potential of single-molecule fluorescence measurements on biomimetic NPCs to elucidate the principles of nuclear transport.
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Affiliation(s)
- Nils Klughammer
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of TechnologyDelftNetherlands
| | - Anders Barth
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of TechnologyDelftNetherlands
| | - Maurice Dekker
- Zernike Institute for Advanced Materials, University of GroningenGroningenNetherlands
| | - Alessio Fragasso
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of TechnologyDelftNetherlands
| | - Patrick R Onck
- Zernike Institute for Advanced Materials, University of GroningenGroningenNetherlands
| | - Cees Dekker
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of TechnologyDelftNetherlands
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3
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Sabri E, Brosseau C. Electromechanical interactions between cell membrane and nuclear envelope: Beyond the standard Schwan's model of biological cells. Bioelectrochemistry 2024; 155:108583. [PMID: 37883860 DOI: 10.1016/j.bioelechem.2023.108583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Revised: 10/02/2023] [Accepted: 10/02/2023] [Indexed: 10/28/2023]
Abstract
We investigate little-appreciated features of the hierarchical core-shell (CS) models of the electrical, mechanical, and electromechanical interactions between the cell membrane (CM) and nuclear envelope (NE). We first consider a simple model of an individual cell based on a coupled resistor-capacitor (Schwan model (SM)) network and show that the CM, when exposed to ac electric fields, acts as a low pass filter while the NE acts as a wide and asymmetric bandpass filter. We provide a simplified calculation for characteristic time associated with the capacitive charging of the NE and parameterize its range of behavior. We furthermore observe several new features dealing with mechanical analogs of the SM based on elementary spring-damper combinations. The chief merit of these models is that they can predict creep compliance responses of an individual cell under static stress and their effective retardation time constants. Next, we use an alternative and a more accurate CS physical model solved by finite element simulations for which geometrical cell reshaping under electromechanical stress (electrodeformation (ED)) is included in a continuum approach with spatial resolution. We show that under an electric field excitation, the elongated nucleus scales differently compared to the electrodeformed cell.
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Affiliation(s)
- Elias Sabri
- Univ Brest, CNRS, Lab-STICC, CS 93837, 6 avenue Le Gorgeu, 29238 Brest Cedex 3, France
| | - Christian Brosseau
- Univ Brest, CNRS, Lab-STICC, CS 93837, 6 avenue Le Gorgeu, 29238 Brest Cedex 3, France.
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4
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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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5
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Patel MK, Chakrabarti B, Panwar AS. Emergence of selectivity and specificity in a coarse-grained model of the nuclear pore complex with sequence-agnostic FG-Nups. Phys Chem Chem Phys 2023; 25:32824-32836. [PMID: 38018404 DOI: 10.1039/d3cp03746k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2023]
Abstract
The role of hydrophobicity of phenylalanine-glycine nucleoporins (FG-Nups) in determining the transport of receptor-bound cargo across the nuclear pore complex (NPC) is investigated using Langevin dynamics simulations. A coarse-grained, minimal model of the NPC, comprising a cylindrical pore and hydrophobic-hydrophilic random copolymers for FG-Nups was employed. Karyopherin-bound receptor-cargo complexes (Kaps) were modeled as rigid, coarse-grained spheres without (inert) and with (patchy) FG-binding hydrophobic domains. With a sequence-agnostic description of FG-Nups and the absence of any anisotropies associated with either NPC or cargo, the model described tracer transport only as a function of FG-Nup hydrophobicity, f. The simulations showed the emergence of two important features of cargo transport, namely, NPC selectivity and specificity. NPC selectivity to patchy tracers emerged due to hydrophobic Kap-FG interactions and despite the sequence-agnostic description of FG-Nups. Furthermore, NPC selectivity was observed only in a specific range of FG-hydrophobic fraction, 0.05 ≤ f ≤ 0.20, resulting in specificity of NPC transport with respect to f. Significantly, this range corresponded to the number fraction of FG-repeats observed in both S. cerevisiae and H. sapiens NPCs. This established the central role of the FG-hydrophobic fraction in determining NPC transport, and provided a biophysical basis for conservation of the FG-Nup hydrophobic fraction across evolutionarily distant NPCs. Specificity in NPC transport emerged from the formation of a hydrogel-like network inside the pore with a characteristic mesh size dependent on f. This network rejected cargo for f > 0.2 based on size exclusion, which resulted in enhanced translocation probability for 0.05 ≤ f ≤ 0.20. Extended brush configurations outside the pore resulted in entropic repulsion and exclusion of inert cargo in this range. Thus, our minimal NPC model exhibited a hybrid cargo translocation mechanism, with aspects of both virtual gate and selective-phase models, in this range of FG-hydrophobic fraction.
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Affiliation(s)
- Manoj K Patel
- Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India.
| | | | - Ajay S Panwar
- Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India.
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6
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Effects of Sequence Composition, Patterning and Hydrodynamics on the Conformation and Dynamics of Intrinsically Disordered Proteins. Int J Mol Sci 2023; 24:ijms24021444. [PMID: 36674958 PMCID: PMC9867189 DOI: 10.3390/ijms24021444] [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: 11/04/2022] [Revised: 12/24/2022] [Accepted: 12/25/2022] [Indexed: 01/13/2023] Open
Abstract
Intrinsically disordered proteins (IDPs) and intrinsically disordered regions (IDRs) perform diverse functions in cellular organization, transport and signaling. Unlike the well-defined structures of the classical natively folded proteins, IDPs and IDRs dynamically span large conformational and structural ensembles. This dynamic disorder impedes the study of the relationship between the amino acid sequences of the IDPs and their spatial structures and dynamics, with different experimental techniques often offering seemingly contradictory results. Although experimental and theoretical evidence indicates that some IDP properties can be understood based on their average biophysical properties and amino acid composition, other aspects of IDP function are dictated by the specifics of the amino acid sequence. We investigate the effects of several key variables on the dimensions and the dynamics of IDPs using coarse-grained polymer models. We focus on the sequence "patchiness" informed by the sequence and biophysical properties of different classes of IDPs-and in particular FG nucleoporins of the nuclear pore complex (NPC). We show that the sequence composition and patterning are well reflected in the global conformational variables such as the radius of gyration and hydrodynamic radius, while the end-to-end distance and dynamics are highly sequence-specific. We find that in good solvent conditions highly heterogeneous sequences of IDPs can be well mapped onto averaged minimal polymer models for the purpose of prediction of the IDPs dimensions and dynamic relaxation times. The coarse-grained simulations are in a good agreement with the results of atomistic MD. We discuss the implications of these results for the interpretation of the recent experimental measurements, and for the further applications of mesoscopic models of FG nucleoporins and IDPs more broadly.
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7
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Morphology of Polymer Brushes in the Presence of Attractive Nanoparticles: Effects of Temperature. Int J Mol Sci 2023; 24:ijms24010832. [PMID: 36614298 PMCID: PMC9821464 DOI: 10.3390/ijms24010832] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 12/22/2022] [Accepted: 12/27/2022] [Indexed: 01/05/2023] Open
Abstract
We study the role of temperature on the structure of pure polymer brushes and their mixture with attractive nanoparticles in flat and cylindrical geometries. It has previously been established that the addition of such nanoparticles causes the polymer brush to collapse and the intensity of the collapse depends on the attraction strength, the nanoparticle diameter, and the grafting density. In this work, we carry out molecular dynamics simulation under good solvent conditions to show how the collapse transition is affected by the temperature, for both plane grafted and inside-cylinder grafted brushes. We first examine the pure brush morphology and verify that the brush height is insensitive to temperature changes in both planar and cylindrical geometries, as expected for a polymer brush in a good solvent. On the other hand, for both system geometries, the brush structure in the presence of attractive nanoparticles is quite responsive to temperature changes. Generally speaking, for a given nanoparticle concentration, increasing the temperature causes the brush height to increase. A brush which contracts when nanoparticles are added eventually swells beyond its pure brush height as the system temperature is increased. The combination of two easily controlled external parameters, namely, concentration of nanoparticles in solution and temperature, allows for sensitive and reversible adjustment of the polymer brush height, a feature which could be exploited in designing smart polymer devices.
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8
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Jafarinia H, Van der Giessen E, Onck PR. Molecular basis of C9orf72 poly-PR interference with the β-karyopherin family of nuclear transport receptors. Sci Rep 2022; 12:21324. [PMID: 36494425 PMCID: PMC9734553 DOI: 10.1038/s41598-022-25732-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Accepted: 12/05/2022] [Indexed: 12/13/2022] Open
Abstract
Nucleocytoplasmic transport (NCT) is affected in several neurodegenerative diseases including C9orf72-ALS. It has recently been found that arginine-containing dipeptide repeat proteins (R-DPRs), translated from C9orf72 repeat expansions, directly bind to several importins. To gain insight into how this can affect nucleocytoplasmic transport, we use coarse-grained molecular dynamics simulations to study the molecular interaction of poly-PR, the most toxic DPR, with several Kapβs (importins and exportins). We show that poly-PR-Kapβ binding depends on the net charge per residue (NCPR) of the Kapβ, salt concentration of the solvent, and poly-PR length. Poly-PR makes contact with the inner surface of most importins, which strongly interferes with Kapβ binding to cargo-NLS, IBB, and RanGTP in a poly-PR length-dependent manner. Longer poly-PRs at higher concentrations are also able to make contact with the outer surface of importins that contain several binding sites to FG-Nups. We also show that poly-PR binds to exportins, especially at lower salt concentrations, interacting with several RanGTP and FG-Nup binding sites. Overall, our results suggest that poly-PR might cause length-dependent defects in cargo loading, cargo release, Kapβ transport and Ran gradient across the nuclear envelope.
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Affiliation(s)
- Hamidreza Jafarinia
- grid.4830.f0000 0004 0407 1981Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747AG Groningen, The Netherlands
| | - Erik Van der Giessen
- grid.4830.f0000 0004 0407 1981Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747AG Groningen, The Netherlands
| | - Patrick R. Onck
- grid.4830.f0000 0004 0407 1981Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747AG Groningen, The Netherlands
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9
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Andersson J, Svirelis J, Medin J, Järlebark J, Hailes R, Dahlin A. Pore performance: artificial nanoscale constructs that mimic the biomolecular transport of the nuclear pore complex. NANOSCALE ADVANCES 2022; 4:4925-4937. [PMID: 36504753 PMCID: PMC9680827 DOI: 10.1039/d2na00389a] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Accepted: 09/12/2022] [Indexed: 06/17/2023]
Abstract
The nuclear pore complex is a nanoscale assembly that achieves shuttle-cargo transport of biomolecules: a certain cargo molecule can only pass the barrier if it is attached to a shuttle molecule. In this review we summarize the most important efforts aiming to reproduce this feature in artificial settings. This can be achieved by solid state nanopores that have been functionalized with the most important proteins found in the biological system. Alternatively, the nanopores are chemically modified with synthetic polymers. However, only a few studies have demonstrated a shuttle-cargo transport mechanism and due to cargo leakage, the selectivity is not comparable to that of the biological system. Other recent approaches are based on DNA origami, though biomolecule transport has not yet been studied with these. The highest selectivity has been achieved with macroscopic gels, but they are yet to be scaled down to nano-dimensions. It is concluded that although several interesting studies exist, we are still far from achieving selective and efficient artificial shuttle-cargo transport of biomolecules. Besides being of fundamental interest, such a system could be potentially useful in bioanalytical devices.
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Affiliation(s)
- John Andersson
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology 41296 Gothenburg Sweden
| | - Justas Svirelis
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology 41296 Gothenburg Sweden
| | - Jesper Medin
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology 41296 Gothenburg Sweden
| | - Julia Järlebark
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology 41296 Gothenburg Sweden
| | - Rebekah Hailes
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology 41296 Gothenburg Sweden
| | - Andreas Dahlin
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology 41296 Gothenburg Sweden
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10
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Ying YL, Hu ZL, Zhang S, Qing Y, Fragasso A, Maglia G, Meller A, Bayley H, Dekker C, Long YT. Nanopore-based technologies beyond DNA sequencing. NATURE NANOTECHNOLOGY 2022; 17:1136-1146. [PMID: 36163504 DOI: 10.1038/s41565-022-01193-2] [Citation(s) in RCA: 118] [Impact Index Per Article: 59.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Accepted: 06/02/2022] [Indexed: 06/16/2023]
Abstract
Inspired by the biological processes of molecular recognition and transportation across membranes, nanopore techniques have evolved in recent decades as ultrasensitive analytical tools for individual molecules. In particular, nanopore-based single-molecule DNA/RNA sequencing has advanced genomic and transcriptomic research due to the portability, lower costs and long reads of these methods. Nanopore applications, however, extend far beyond nucleic acid sequencing. In this Review, we present an overview of the broad applications of nanopores in molecular sensing and sequencing, chemical catalysis and biophysical characterization. We highlight the prospects of applying nanopores for single-protein analysis and sequencing, single-molecule covalent chemistry, clinical sensing applications for single-molecule liquid biopsy, and the use of synthetic biomimetic nanopores as experimental models for natural systems. We suggest that nanopore technologies will continue to be explored to address a number of scientific challenges as control over pore design improves.
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Affiliation(s)
- Yi-Lun Ying
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, People's Republic of China
| | - Zheng-Li Hu
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, People's Republic of China
| | - Shengli Zhang
- Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, the Netherlands
| | - Yujia Qing
- Department of Chemistry, University of Oxford, Oxford, UK
| | - Alessio Fragasso
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Delft, the Netherlands
| | - Giovanni Maglia
- Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, the Netherlands.
| | - Amit Meller
- Faculty of Biomedical Engineering, Technion-IIT, Haifa, Israel.
| | - Hagan Bayley
- Department of Chemistry, University of Oxford, Oxford, UK.
| | - Cees Dekker
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Delft, the Netherlands.
| | - Yi-Tao Long
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, People's Republic of China.
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11
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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: 15] [Impact Index Per Article: 7.5] [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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12
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Chowdhury R, Sau A, Musser SM. Super-resolved 3D tracking of cargo transport through nuclear pore complexes. Nat Cell Biol 2022; 24:112-122. [PMID: 35013558 PMCID: PMC8820391 DOI: 10.1038/s41556-021-00815-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Accepted: 11/12/2021] [Indexed: 12/14/2022]
Abstract
Nuclear pore complexes (NPCs) embedded within the nuclear envelope (NE) mediate rapid, selective, and bidirectional traffic between the cytoplasm and the nucleoplasm. Deciphering the mechanism and dynamics of this process is challenged by the need for high spatial and temporal precision. We report here a multi-color imaging approach that enables direct 3D visualization of cargo transport trajectories relative to a super-resolved octagonal double-ring structure of the NPC scaffold. The success of this approach is enabled by the high positional stability of NPCs within permeabilized cells, as verified by a combined experimental and simulation analysis. Hourglass-shaped translocation conduits for two cargo complexes representing different nuclear transport receptor (NTR) pathways indicates rapid migration through the permeability barrier on or near the NPC scaffold. Binding sites for cargo complexes extend over 100 nm from the pore openings, consistent with a wide distribution of the FG-polypeptides that bind NTRs.
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Affiliation(s)
- Rajdeep Chowdhury
- Department of Molecular and Cellular Medicine, Texas A&M University, College of Medicine, The Texas A&M Health Science Center, College Station, TX, USA
| | - Abhishek Sau
- Department of Molecular and Cellular Medicine, Texas A&M University, College of Medicine, The Texas A&M Health Science Center, College Station, TX, USA
| | - Siegfried M Musser
- Department of Molecular and Cellular Medicine, Texas A&M University, College of Medicine, The Texas A&M Health Science Center, College Station, TX, USA.
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13
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Corti HR, Appignanesi GA, Barbosa MC, Bordin JR, Calero C, Camisasca G, Elola MD, Franzese G, Gallo P, Hassanali A, Huang K, Laria D, Menéndez CA, de Oca JMM, Longinotti MP, Rodriguez J, Rovere M, Scherlis D, Szleifer I. Structure and dynamics of nanoconfined water and aqueous solutions. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2021; 44:136. [PMID: 34779954 DOI: 10.1140/epje/s10189-021-00136-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Accepted: 10/06/2021] [Indexed: 06/13/2023]
Abstract
This review is devoted to discussing recent progress on the structure, thermodynamic, reactivity, and dynamics of water and aqueous systems confined within different types of nanopores, synthetic and biological. Currently, this is a branch of water science that has attracted enormous attention of researchers from different fields interested to extend the understanding of the anomalous properties of bulk water to the nanoscopic domain. From a fundamental perspective, the interactions of water and solutes with a confining surface dramatically modify the liquid's structure and, consequently, both its thermodynamical and dynamical behaviors, breaking the validity of the classical thermodynamic and phenomenological description of the transport properties of aqueous systems. Additionally, man-made nanopores and porous materials have emerged as promising solutions to challenging problems such as water purification, biosensing, nanofluidic logic and gating, and energy storage and conversion, while aquaporin, ion channels, and nuclear pore complex nanopores regulate many biological functions such as the conduction of water, the generation of action potentials, and the storage of genetic material. In this work, the more recent experimental and molecular simulations advances in this exciting and rapidly evolving field will be reported and critically discussed.
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Affiliation(s)
- Horacio R Corti
- Departmento de Física de la Materia Condensada & Instituto de Nanociencia y Nanotecnología (CNEA-CONICET), Comisión Nacional de Energía Atómica, B1650LWP, Buenos Aires, Argentina.
| | - Gustavo A Appignanesi
- INQUISUR, Departamento de Química, Universidad Nacional del Sur (UNS)-CONICET, 8000, Bahía Blanca, Argentina
| | - Marcia C Barbosa
- Institute of Physics, Federal University of Rio Grande do Sul, 91501-970, Porto Alegre, Brazil
| | - J Rafael Bordin
- Department of Physics, Institute of Physics and Mathematics, 96050-500, Pelotas, RS, Brazil
| | - Carles Calero
- Secció de Física Estadística i Interdisciplinària - Departament de Física de la Matèria Condensada, Universitat de Barcelona & Institut de Nanociència i Nanotecnologia (IN2UB), Universitat de Barcelona, 08028, Barcelona, Spain
| | - Gaia Camisasca
- Dipartimento di Matematica e Fisica, Università degli Studi Roma Tre, 00146, Roma, Italy
| | - M Dolores Elola
- Departmento de Física de la Materia Condensada & Instituto de Nanociencia y Nanotecnología (CNEA-CONICET), Comisión Nacional de Energía Atómica, B1650LWP, Buenos Aires, Argentina
| | - Giancarlo Franzese
- Secció de Física Estadística i Interdisciplinària - Departament de Física de la Matèria Condensada, Universitat de Barcelona & Institut de Nanociència i Nanotecnologia (IN2UB), Universitat de Barcelona, 08028, Barcelona, Spain
| | - Paola Gallo
- Dipartimento di Matematica e Fisica, Università degli Studi Roma Tre, 00146, Roma, Italy
| | - Ali Hassanali
- Condensed Matter and Statistical Physics Section (CMSP), The International Center for Theoretical Physics (ICTP), Trieste, Italy
| | - Kai Huang
- Institute of Systems and Physical Biology, Shenzhen Bay Laboratory, Shenzhen, Guangdong, China
| | - Daniel Laria
- Departmento de Física de la Materia Condensada & Instituto de Nanociencia y Nanotecnología (CNEA-CONICET), Comisión Nacional de Energía Atómica, B1650LWP, Buenos Aires, Argentina
- Instituto de Química Física de los Materiales, Medio Ambiente y Energía (INQUIMAE-CONICET), Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Cintia A Menéndez
- INQUISUR, Departamento de Química, Universidad Nacional del Sur (UNS)-CONICET, 8000, Bahía Blanca, Argentina
| | - Joan M Montes de Oca
- INQUISUR, Departamento de Química, Universidad Nacional del Sur (UNS)-CONICET, 8000, Bahía Blanca, Argentina
| | - M Paula Longinotti
- Instituto de Química Física de los Materiales, Medio Ambiente y Energía (INQUIMAE-CONICET), Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Javier Rodriguez
- Departmento de Física de la Materia Condensada & Instituto de Nanociencia y Nanotecnología (CNEA-CONICET), Comisión Nacional de Energía Atómica, B1650LWP, Buenos Aires, Argentina
- Escuela de Ciencia y Tecnología, Universidad Nacional de General San Martín, San Martín, Buenos Aires, Argentina
| | - Mauro Rovere
- Dipartimento di Matematica e Fisica, Università degli Studi Roma Tre, 00146, Roma, Italy
| | - Damián Scherlis
- Instituto de Química Física de los Materiales, Medio Ambiente y Energía (INQUIMAE-CONICET), Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Igal Szleifer
- Biomedical Engineering Department, Northwestern University, Evanston, USA
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14
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Fujinami Tanimoto IM, Cressiot B, Jarroux N, Roman J, Patriarche G, Le Pioufle B, Pelta J, Bacri L. Selective target protein detection using a decorated nanopore into a microfluidic device. Biosens Bioelectron 2021; 183:113195. [PMID: 33857755 DOI: 10.1016/j.bios.2021.113195] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 03/19/2021] [Accepted: 03/20/2021] [Indexed: 10/21/2022]
Abstract
Solid-state nanopores provide a powerful tool to electrically analyze nanoparticles and biomolecules at single-molecule resolution. These biosensors need to have a controlled surface to provide information about the analyte. Specific detection remains limited due to nonspecific interactions between the molecules and the nanopore. Here, a polymer surface modification to passivate the membrane is performed. This functionalization improves nanopore stability and ionic conduction. Moreover, one can control the nanopore diameter and the specific interactions between protein and pore surface. The effect of ionic strength and pH are probed. Which enables control of the electroosmotic driving force and dynamics. Furthermore, a study of polymer chain structure and permeability in the pore are carried out. The nanopore chip is integrated into a microfluidic device to ease its handling. Finally, a discussion of an ionic conductance model through a permeable crown along the nanopore surface is elucidated. The proof of concept is demonstrated by the capture of free streptavidin by the biotins grafted into the nanopore. In the future, this approach could be used for virus diagnostic, nanoparticle or biomarker sensing.
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Affiliation(s)
- Izadora Mayumi Fujinami Tanimoto
- Université Paris-Saclay, Univ Evry, CNRS, LAMBE, 91025, Evry-Courcouronnes, France; Université Paris-Saclay, ENS Paris-Saclay, CNRS, LuMIn, Institut d'Alembert, 91190, Gif-sur-Yvette, France
| | | | - Nathalie Jarroux
- Université Paris-Saclay, Univ Evry, CNRS, LAMBE, 91025, Evry-Courcouronnes, France
| | - Jean Roman
- Université Paris-Saclay, ENS Paris-Saclay, CNRS, LuMIn, Institut d'Alembert, 91190, Gif-sur-Yvette, France
| | - Gilles Patriarche
- Université Paris-Saclay, CNRS, Centre de Nanosciences et de Nanotechnologies, 91120, Palaiseau, France
| | - Bruno Le Pioufle
- Université Paris-Saclay, ENS Paris-Saclay, CNRS, LuMIn, Institut d'Alembert, 91190, Gif-sur-Yvette, France.
| | - Juan Pelta
- Université Paris-Saclay, Univ Evry, CNRS, LAMBE, 91025, Evry-Courcouronnes, France.
| | - Laurent Bacri
- Université Paris-Saclay, Univ Evry, CNRS, LAMBE, 91025, Evry-Courcouronnes, France.
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15
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A designer FG-Nup that reconstitutes the selective transport barrier of the nuclear pore complex. Nat Commun 2021; 12:2010. [PMID: 33790297 PMCID: PMC8012357 DOI: 10.1038/s41467-021-22293-y] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Accepted: 03/01/2021] [Indexed: 02/01/2023] Open
Abstract
Nuclear Pore Complexes (NPCs) regulate bidirectional transport between the nucleus and the cytoplasm. Intrinsically disordered FG-Nups line the NPC lumen and form a selective barrier, where transport of most proteins is inhibited whereas specific transporter proteins freely pass. The mechanism underlying selective transport through the NPC is still debated. Here, we reconstitute the selective behaviour of the NPC bottom-up by introducing a rationally designed artificial FG-Nup that mimics natural Nups. Using QCM-D, we measure selective binding of the artificial FG-Nup brushes to the transport receptor Kap95 over cytosolic proteins such as BSA. Solid-state nanopores with the artificial FG-Nups lining their inner walls support fast translocation of Kap95 while blocking BSA, thus demonstrating selectivity. Coarse-grained molecular dynamics simulations highlight the formation of a selective meshwork with densities comparable to native NPCs. Our findings show that simple design rules can recapitulate the selective behaviour of native FG-Nups and demonstrate that no specific spacer sequence nor a spatial segregation of different FG-motif types are needed to create selective NPCs.
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16
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Conformation of Polyethylene Glycol inside Confined Space: Simulation and Experimental Approaches. NANOMATERIALS 2021; 11:nano11010244. [PMID: 33477748 PMCID: PMC7832411 DOI: 10.3390/nano11010244] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Revised: 01/12/2021] [Accepted: 01/14/2021] [Indexed: 02/08/2023]
Abstract
The modification of the inner nanopore wall by polymers is currently used to change the specific properties of the nanosystem. Among them, the polyethylene glycol (PEG) is the most used to prevent the fouling and ensure the wettability. However, its properties depend mainly on the chain structure that is very difficult to estimate inside this confined space. Combining experimental and simulation approaches, we provide an insight to the consequence of the PEG presence inside the nanopore on the nanopore properties. We show, in particular, that the cation type in the electrolyte, together with the type of electrolyte (water or urea), is at the origin of the ion transport modification in the nanopore.
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17
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Crnković A, Srnko M, Anderluh G. Biological Nanopores: Engineering on Demand. Life (Basel) 2021; 11:life11010027. [PMID: 33466427 PMCID: PMC7824896 DOI: 10.3390/life11010027] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 12/24/2020] [Accepted: 12/31/2020] [Indexed: 12/17/2022] Open
Abstract
Nanopore-based sensing is a powerful technique for the detection of diverse organic and inorganic molecules, long-read sequencing of nucleic acids, and single-molecule analyses of enzymatic reactions. Selected from natural sources, protein-based nanopores enable rapid, label-free detection of analytes. Furthermore, these proteins are easy to produce, form pores with defined sizes, and can be easily manipulated with standard molecular biology techniques. The range of possible analytes can be extended by using externally added adapter molecules. Here, we provide an overview of current nanopore applications with a focus on engineering strategies and solutions.
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18
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Theoretical Modeling of Chemical Equilibrium in Weak Polyelectrolyte Layers on Curved Nanosystems. Polymers (Basel) 2020; 12:polym12102282. [PMID: 33027995 PMCID: PMC7601300 DOI: 10.3390/polym12102282] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 09/24/2020] [Accepted: 09/24/2020] [Indexed: 12/19/2022] Open
Abstract
Surface functionalization with end-tethered weak polyelectrolytes (PE) is a versatile way to modify and control surface properties, given their ability to alter their degree of charge depending on external cues like pH and salt concentration. Weak PEs find usage in a wide range of applications, from colloidal stabilization, lubrication, adhesion, wetting to biomedical applications such as drug delivery and theranostics applications. They are also ubiquitous in many biological systems. Here, we present an overview of some of the main theoretical methods that we consider key in the field of weak PE at interfaces. Several applications involving engineered nanoparticles, synthetic and biological nanopores, as well as biological macromolecules are discussed to illustrate the salient features of systems involving weak PE near an interface or under (nano)confinement. The key feature is that by confining weak PEs near an interface the degree of charge is different from what would be expected in solution. This is the result of the strong coupling between structural organization of weak PE and its chemical state. The responsiveness of engineered and biological nanomaterials comprising weak PE combined with an adequate level of modeling can provide the keys to a rational design of smart nanosystems.
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19
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Jafarinia H, van der Giessen E, Onck PR. Phase Separation of Toxic Dipeptide Repeat Proteins Related to C9orf72 ALS/FTD. Biophys J 2020; 119:843-851. [PMID: 32730793 DOI: 10.1016/j.bpj.2020.07.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Revised: 06/28/2020] [Accepted: 07/06/2020] [Indexed: 10/23/2022] Open
Abstract
The expansion mutation in the C9orf72 gene is the most common known genetic cause for amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). This mutation can produce five dipeptide repeat proteins (DPRs), of which three are known to be toxic: poly-PR, poly-GR, and poly-GA. The toxicity of poly-GA is attributed to its aggregation in the cytoplasm, whereas for poly-PR and poly-GR, several toxicity pathways have been proposed. The toxicity of the DPRs has been shown to depend on their length, but the underlying molecular mechanism of this length dependence is not well understood. To address the possible role of phase separation in DPR toxicity, a one-bead-per-amino-acid (1BPA) coarse-grained molecular dynamics model is used to study the single-molecule and phase-separation properties of the DPRs. We find a strong dependence of the phase-separation behavior on both DPR length and concentration, with longer DPRs having a higher propensity to phase separate and form condensed phases with higher concentrations. The critical lengths required for phase separation (25 for poly-PR and 50 for poly-GA) are comparable to the toxicity threshold limit of 30 repeats found for the expansion mutation in patient cells, suggesting that phase separation could play an important role in DPR toxicity.
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Affiliation(s)
- Hamidreza Jafarinia
- Zernike Institute for Advanced Materials, University of Groningen, Groningen, the Netherlands
| | - Erik van der Giessen
- Zernike Institute for Advanced Materials, University of Groningen, Groningen, the Netherlands
| | - Patrick R Onck
- Zernike Institute for Advanced Materials, University of Groningen, Groningen, the Netherlands.
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20
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Hayama R, Sorci M, Keating IV JJ, Hecht LM, Plawsky JL, Belfort G, Chait BT, Rout MP. Interactions of nuclear transport factors and surface-conjugated FG nucleoporins: Insights and limitations. PLoS One 2019; 14:e0217897. [PMID: 31170242 PMCID: PMC6553764 DOI: 10.1371/journal.pone.0217897] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Accepted: 05/21/2019] [Indexed: 11/18/2022] Open
Abstract
Protein-protein interactions are central to biological processes. In vitro methods to examine protein-protein interactions are generally categorized into two classes: in-solution and surface-based methods. Here, using the multivalent interactions between nucleocytoplasmic transport factors and intrinsically disordered FG repeat containing nuclear pore complex proteins as a model system, we examined the utility of three surface-based methods: atomic force microscopy, quartz crystal microbalance with dissipation, and surface plasmon resonance. Although results were comparable to those of previous reports, the apparent effect of mass transport limitations was demonstrated. Additional experiments with a loss-of-interaction FG repeat mutant variant demonstrated that the binding events that take place on surfaces can be unexpectedly complex, suggesting particular care must be exercised in interpretation of such data.
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Affiliation(s)
- Ryo Hayama
- Laboratory of Cellular and Structural Biology, the Rockefeller University, New York, NY, United States of America
| | - Mirco Sorci
- Department of Chemical and Biological Engineering and Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY, United States of America
| | - John J. Keating IV
- Department of Chemical and Biological Engineering and Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY, United States of America
| | - Lee M. Hecht
- Laboratory of Cellular and Structural Biology, the Rockefeller University, New York, NY, United States of America
| | - Joel L. Plawsky
- Department of Chemical and Biological Engineering and Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY, United States of America
| | - Georges Belfort
- Department of Chemical and Biological Engineering and Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY, United States of America
- * E-mail: (GB); (BTC); (MPR)
| | - Brian T. Chait
- Laboratory of Mass Spectrometry and Gaseous Chemistry, the Rockefeller University, New York, NY, United States of America
- * E-mail: (GB); (BTC); (MPR)
| | - Michael P. Rout
- Laboratory of Cellular and Structural Biology, the Rockefeller University, New York, NY, United States of America
- * E-mail: (GB); (BTC); (MPR)
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21
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Pathirathna P, Balla RJ, Jantz DT, Kurapati N, Gramm ER, Leonard KC, Amemiya S. Probing High Permeability of Nuclear Pore Complexes by Scanning Electrochemical Microscopy: Ca 2+ Effects on Transport Barriers. Anal Chem 2019; 91:5446-5454. [PMID: 30907572 PMCID: PMC6535230 DOI: 10.1021/acs.analchem.9b00796] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The nuclear pore complex (NPC) solely mediates molecular transport between the nucleus and cytoplasm of a eukaryotic cell to play important biological and biomedical roles. However, it is not well-understood chemically how this biological nanopore selectively and efficiently transports various substances, including small molecules, proteins, and RNAs by using transport barriers that are rich in highly disordered repeats of hydrophobic phenylalanine and glycine intermingled with charged amino acids. Herein, we employ scanning electrochemical microscopy to image and measure the high permeability of NPCs to small redox molecules. The effective medium theory demonstrates that the measured permeability is controlled by diffusional translocation of probe molecules through water-filled nanopores without steric or electrostatic hindrance from hydrophobic or charged regions of transport barriers, respectively. However, the permeability of NPCs is reduced by a low millimolar concentration of Ca2+, which can interact with anionic regions of transport barriers to alter their spatial distributions within the nanopore. We employ atomic force microscopy to confirm that transport barriers of NPCs are dominantly recessed (∼80%) or entangled (∼20%) at the high Ca2+ level in contrast to authentic populations of entangled (∼50%), recessed (∼25%), and "plugged" (∼25%) conformations at a physiological Ca2+ level of submicromolar. We propose a model for synchronized Ca2+ effects on the conformation and permeability of NPCs, where transport barriers are viscosified to lower permeability. Significantly, this result supports a hypothesis that the functional structure of transport barriers is maintained not only by their hydrophobic regions, but also by charged regions.
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Affiliation(s)
- Pavithra Pathirathna
- Department of Chemistry, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, Pennsylvania, 15260, United States
| | - Ryan J. Balla
- Department of Chemistry, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, Pennsylvania, 15260, United States
| | - Dylan T. Jantz
- Center for Environmentally Beneficial Catalysis, Department of Chemical and Petroleum Engineering, University of Kansas, 1501 Wakarusa Drive, Lawrence, Kansas 66047, United States
| | - Niraja Kurapati
- Department of Chemistry, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, Pennsylvania, 15260, United States
| | - Erin R. Gramm
- Department of Chemistry, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, Pennsylvania, 15260, United States
| | - Kevin C. Leonard
- Center for Environmentally Beneficial Catalysis, Department of Chemical and Petroleum Engineering, University of Kansas, 1501 Wakarusa Drive, Lawrence, Kansas 66047, United States
| | - Shigeru Amemiya
- Department of Chemistry, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, Pennsylvania, 15260, United States
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22
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Gu C, Vovk A, Zheng T, Coalson RD, Zilman A. The Role of Cohesiveness in the Permeability of the Spatial Assemblies of FG Nucleoporins. Biophys J 2019; 116:1204-1215. [PMID: 30902367 DOI: 10.1016/j.bpj.2019.02.028] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Revised: 11/02/2018] [Accepted: 02/26/2019] [Indexed: 12/31/2022] Open
Abstract
Nuclear pore complexes (NPCs) conduct selective, bidirectional transport across the nuclear envelope. The NPC passageway is lined by intrinsically disordered proteins that contain hydrophobic phenylalanine-glycine (FG) motifs, known as FG nucleoporins (FG nups), that play the key role in the NPC transport mechanism. Cohesive interactions among the FG nups, which arise from the combination of hydrophobic, electrostatic, and other forces, have been hypothesized to control the morphology of the assemblies of FG nups in the NPC, as well as their permeability with respect to the transport proteins. However, the role of FG nup cohesiveness is still vigorously debated. Using coarse-grained polymer theory and numerical simulations, we study the effects of cohesiveness on the selective permeability of in vitro FG nup assemblies in different geometries that have served as proxies for the morphological and transport properties of the NPC. We show that in high-density FG nup assemblies, increase in cohesiveness leads to the decrease in their permeability, in accordance with the accepted view. On the other hand, the permeability of low-density assemblies is a nonmonotonic function of the cohesiveness, and a moderate increase in cohesiveness can enhance permeability. The density- and cohesiveness-dependent effects on permeability are explained by considering the free-energy cost associated with penetrating the FG nup assemblies. We discuss the implications of these findings for the organization and function of the NPC.
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Affiliation(s)
- Chad Gu
- Department of Physics, University of Toronto, Toronto, Ontario, Canada
| | - Andrei Vovk
- Department of Physics, University of Toronto, Toronto, Ontario, Canada
| | - Tiantian Zheng
- Department of Physics, University of Toronto, Toronto, Ontario, Canada
| | - Rob D Coalson
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Anton Zilman
- Department of Physics, University of Toronto, Toronto, Ontario, Canada; Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada.
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23
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The Effect of FG-Nup Phosphorylation on NPC Selectivity: A One-Bead-Per-Amino-Acid Molecular Dynamics Study. Int J Mol Sci 2019; 20:ijms20030596. [PMID: 30704069 PMCID: PMC6387328 DOI: 10.3390/ijms20030596] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Revised: 01/21/2019] [Accepted: 01/23/2019] [Indexed: 01/16/2023] Open
Abstract
Nuclear pore complexes (NPCs) are large protein complexes embedded in the nuclear envelope separating the cytoplasm from the nucleoplasm in eukaryotic cells. They function as selective gates for the transport of molecules in and out of the nucleus. The inner wall of the NPC is coated with intrinsically disordered proteins rich in phenylalanine-glycine repeats (FG-repeats), which are responsible for the intriguing selectivity of NPCs. The phosphorylation state of the FG-Nups is controlled by kinases and phosphatases. In the current study, we extended our one-bead-per-amino-acid (1BPA) model for intrinsically disordered proteins to account for phosphorylation. With this, we performed molecular dynamics simulations to probe the effect of phosphorylation on the Stokes radius of isolated FG-Nups, and on the structure and transport properties of the NPC. Our results indicate that phosphorylation causes a reduced attraction between the residues, leading to an extension of the FG-Nups and the formation of a significantly less dense FG-network inside the NPC. Furthermore, our simulations show that upon phosphorylation, the transport rate of inert molecules increases, while that of nuclear transport receptors decreases, which can be rationalized in terms of modified hydrophobic, electrostatic, and steric interactions. Altogether, our models provide a molecular framework to explain how extensive phosphorylation of FG-Nups decreases the selectivity of the NPC.
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24
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Ketterer P, Ananth AN, Laman Trip DS, Mishra A, Bertosin E, Ganji M, van der Torre J, Onck P, Dietz H, Dekker C. DNA origami scaffold for studying intrinsically disordered proteins of the nuclear pore complex. Nat Commun 2018; 9:902. [PMID: 29500415 PMCID: PMC5834454 DOI: 10.1038/s41467-018-03313-w] [Citation(s) in RCA: 83] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Accepted: 02/02/2018] [Indexed: 11/09/2022] Open
Abstract
The nuclear pore complex (NPC) is the gatekeeper for nuclear transport in eukaryotic cells. A key component of the NPC is the central shaft lined with intrinsically disordered proteins (IDPs) known as FG-Nups, which control the selective molecular traffic. Here, we present an approach to realize artificial NPC mimics that allows controlling the type and copy number of FG-Nups. We constructed 34 nm-wide 3D DNA origami rings and attached different numbers of NSP1, a model yeast FG-Nup, or NSP1-S, a hydrophilic mutant. Using (cryo) electron microscopy, we find that NSP1 forms denser cohesive networks inside the ring compared to NSP1-S. Consistent with this, the measured ionic conductance is lower for NSP1 than for NSP1-S. Molecular dynamics simulations reveal spatially varying protein densities and conductances in good agreement with the experiments. Our technique provides an experimental platform for deciphering the collective behavior of IDPs with full control of their type and position.
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Affiliation(s)
- Philip Ketterer
- Physik Department and Institute for Advanced Study, Technische Universität München, Am Coulombwall 4a, Garching bei München, D-85748, Germany
| | - Adithya N Ananth
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Van der Maasweg 9, 2629 HZ, Delft, The Netherlands
| | - Diederik S Laman Trip
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Van der Maasweg 9, 2629 HZ, Delft, The Netherlands
| | - Ankur Mishra
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747AG, Groningen, The Netherlands
| | - Eva Bertosin
- Physik Department and Institute for Advanced Study, Technische Universität München, Am Coulombwall 4a, Garching bei München, D-85748, Germany
| | - Mahipal Ganji
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Van der Maasweg 9, 2629 HZ, Delft, The Netherlands
| | - Jaco van der Torre
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Van der Maasweg 9, 2629 HZ, Delft, The Netherlands
| | - Patrick Onck
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747AG, Groningen, The Netherlands
| | - Hendrik Dietz
- Physik Department and Institute for Advanced Study, Technische Universität München, Am Coulombwall 4a, Garching bei München, D-85748, Germany.
| | - Cees Dekker
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Van der Maasweg 9, 2629 HZ, Delft, The Netherlands.
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