1
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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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2
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Andreu I, Granero-Moya I, Garcia-Manyes S, Roca-Cusachs P. Understanding the role of mechanics in nucleocytoplasmic transport. APL Bioeng 2022; 6:020901. [PMID: 35783457 PMCID: PMC9246425 DOI: 10.1063/5.0076034] [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: 10/20/2021] [Accepted: 02/03/2022] [Indexed: 01/26/2023] Open
Abstract
Cell nuclei are submitted to mechanical forces, which in turn affect nuclear and cell functions. Recent evidence shows that a crucial mechanically regulated nuclear function is nucleocytoplasmic transport, mediated by nuclear pore complexes (NPCs). Mechanical regulation occurs at two levels: first, by force application to the nucleus, which increases NPC permeability likely through NPC stretch. Second, by the mechanical properties of the transported proteins themselves, as mechanically labile proteins translocate through NPCs faster than mechanically stiff ones. In this perspective, we discuss this evidence and the associated mechanisms by which mechanics can regulate the nucleo-cytoplasmic partitioning of proteins. Finally, we analyze how mechanical regulation of nucleocytoplasmic transport can provide a systematic approach to the study of mechanobiology and open new avenues both in fundamental and applied research.
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Affiliation(s)
- Ion Andreu
- Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Technology (BIST), 08028 Barcelona, Spain
| | | | - Sergi Garcia-Manyes
- Department of Physics, Randall Centre for Cell and Molecular Biophysics, King's College London, WC2R 2LS London, United Kingdom; Single Molecule Mechanobiology Laboratory, The Francis Crick Institute, NW1 1AT London, United Kingdom
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3
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Eckels EC, Chaudhuri D, Chakraborty S, Echelman DJ, Haldar S. DsbA is a redox-switchable mechanical chaperone. Chem Sci 2021; 12:11109-11120. [PMID: 34522308 PMCID: PMC8386657 DOI: 10.1039/d1sc03048e] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2021] [Accepted: 07/17/2021] [Indexed: 12/18/2022] Open
Abstract
DsbA is a ubiquitous bacterial oxidoreductase that associates with substrates during and after translocation, yet its involvement in protein folding and translocation remains an open question. Here we demonstrate a redox-controlled chaperone activity of DsbA, on both cysteine-containing and cysteine-free substrates, using magnetic tweezers-based single molecule force spectroscopy that enables independent measurements of oxidoreductase activity and chaperone behavior. Interestingly we found that this chaperone activity is tuned by the oxidation state of DsbA; oxidized DsbA is a strong promoter of folding, but the effect is weakened by the reduction of the catalytic CXXC motif. We further localize the chaperone binding site of DsbA using a seven-residue peptide which effectively blocks the chaperone activity. We found that the DsbA assisted folding of proteins in the periplasm generates enough mechanical work to decrease the ATP consumption needed for periplasmic translocation by up to 33%.
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Affiliation(s)
- Edward C Eckels
- Department of Biological Sciences, Columbia University New York NY 10027 USA
- Department of Internal Medicine, Columbia University Medical Center New York NY 10032 USA
| | - Deep Chaudhuri
- Department of Biological Sciences, Ashoka University Sonepat Haryana 131029 India
| | - Soham Chakraborty
- Department of Biological Sciences, Ashoka University Sonepat Haryana 131029 India
| | - Daniel J Echelman
- Department of Biological Sciences, Columbia University New York NY 10027 USA
| | - Shubhasis Haldar
- Department of Biological Sciences, Ashoka University Sonepat Haryana 131029 India
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4
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Di Natale C, Natale CF, Florio D, Netti PA, Morelli G, Ventre M, Marasco D. Effects of surface nanopatterning on internalization and amyloid aggregation of the fragment 264-277 of Nucleophosmin 1. Colloids Surf B Biointerfaces 2020; 197:111439. [PMID: 33137636 DOI: 10.1016/j.colsurfb.2020.111439] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 10/06/2020] [Accepted: 10/20/2020] [Indexed: 12/17/2022]
Abstract
The mechanical interpretation of the plethora of factors that governs cellular localization of amyloid aggregates is crucial for planning novel therapeutical interventions in neurodegenerative diseases since these aggregates exert a primary role in the proteostasis machinery. The uptake of Cell Penetrating Peptides (CPPs) conjugated with different amyloid polypeptides occurs via different endocytic processes regulated by cytoskeleton organization and cell morphology. Herein, we deepened the internalization of an amyloid system in cells cultured on nanopatterned surfaces that represent a powerful tool to shape cell and regulate its contractility. We analyzed the behavior of an amyloid model system, employing NPM1264-277 sequence, covalently conjugated to Tat fragment 48-60 as CPP. To investigate its internalization mechanism, we followed the formation of aggregates on two kinds of substrates: a flat and a nanopatterned surface. Herein, investigations during time were carried out by employing both confocal and second harmonic generation (SHG) microscopies. We showed that modifications of cellular environment affect peptide localization, its cytoplasmic translocation and the size of amyloid aggregates.
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Affiliation(s)
- Concetta Di Natale
- Department of Pharmacy, University of Naples "Federico II", Italy; Center for Advanced Biomaterial for Health Care (CABHC), Istituto Italiano di Tecnologia, Naples, Italy; Interdisciplinary Research Centre on Biomaterials (CRIB), University of Naples Federico II, Piazzale Tecchio 80, 80125 Naples, Italy
| | - Carlo F Natale
- Interdisciplinary Research Centre on Biomaterials (CRIB), University of Naples Federico II, Piazzale Tecchio 80, 80125 Naples, Italy
| | - Daniele Florio
- Department of Pharmacy, University of Naples "Federico II", Italy
| | - Paolo Antonio Netti
- Center for Advanced Biomaterial for Health Care (CABHC), Istituto Italiano di Tecnologia, Naples, Italy; Interdisciplinary Research Centre on Biomaterials (CRIB), University of Naples Federico II, Piazzale Tecchio 80, 80125 Naples, Italy; Department of Chemical, Materials and Industrial Production Engineering (DICMAPI), University of Naples Federico II, Piazzale Tecchio 80, 80125 Naples, Italy
| | | | - Maurizio Ventre
- Center for Advanced Biomaterial for Health Care (CABHC), Istituto Italiano di Tecnologia, Naples, Italy; Interdisciplinary Research Centre on Biomaterials (CRIB), University of Naples Federico II, Piazzale Tecchio 80, 80125 Naples, Italy; Department of Chemical, Materials and Industrial Production Engineering (DICMAPI), University of Naples Federico II, Piazzale Tecchio 80, 80125 Naples, Italy
| | - Daniela Marasco
- Department of Pharmacy, University of Naples "Federico II", Italy
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5
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Protein mechanics probed using simple molecular models. Biochim Biophys Acta Gen Subj 2020; 1864:129613. [DOI: 10.1016/j.bbagen.2020.129613] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 03/06/2020] [Accepted: 04/08/2020] [Indexed: 01/14/2023]
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6
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Rosen CB, Bayley H, Rodriguez-Larrea D. Free-energy landscapes of membrane co-translocational protein unfolding. Commun Biol 2020; 3:160. [PMID: 32246057 PMCID: PMC7125183 DOI: 10.1038/s42003-020-0841-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Accepted: 02/20/2020] [Indexed: 11/09/2022] Open
Abstract
Protein post-translational translocation is found at the plasma membrane of prokaryotes and protein import into organellae. Translocon structures are becoming available, however the dynamics of proteins during membrane translocation remain largely obscure. Here we study, at the single-molecule level, the folding landscape of a model protein while forced to translocate a transmembrane pore. We use a DNA tag to drive the protein into the α-hemolysin pore under a quantifiable force produced by an applied electric potential. Using a voltage-quench approach we find that the protein fluctuates between the native state and an intermediate in the translocation process at estimated forces as low as 1.9 pN. The fluctuation kinetics provide the free energy landscape as a function of force. We show that our stable, ≈15 kBT, substrate can be unfolded and translocated with physiological membrane potentials and that selective divalent cation binding may have a profound effect on the translocation kinetics.
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Affiliation(s)
- Christian Bech Rosen
- Department of Chemistry, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK.,Novozymes A/S, Biologiens Vej 2, 2800, Kgs. Lyngby, Denmark
| | - Hagan Bayley
- Department of Chemistry, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK
| | - David Rodriguez-Larrea
- Biofisika Institute (CSIC, UPV/EHU) and Department of Biochemistry and Molecular Biology (UPV/EHU) Barrio Sarriena s/n, Leioa, 48940, Spain.
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7
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Sato TK, Kawano S, Endo T. Role of the membrane potential in mitochondrial protein unfolding and import. Sci Rep 2019; 9:7637. [PMID: 31114030 PMCID: PMC6529458 DOI: 10.1038/s41598-019-44152-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Accepted: 05/10/2019] [Indexed: 12/02/2022] Open
Abstract
Newly synthesized mitochondrial precursor proteins have to become unfolded to cross the mitochondrial membranes. This unfolding is achieved primarily by mitochondrial Hsp70 (mtHsp70) for presequence-containing precursor proteins. However, the membrane potential across the inner membrane (ΔΨ) could also contribute to unfolding of short-presequence containing mitochondrial precursor proteins. Here we investigated the role of ΔΨ in mitochondrial protein unfolding and import. We found that the effects of mutations in the presequence on import rates are correlated well with the hydrophobicity or ability to interact with import motor components including mtHsp70, but not with ΔΨ (negative inside). A spontaneously unfolded precursor protein with a short presequence is therefore trapped by motor components including mtHsp70, but not ΔΨ, which could cause global unfolding of the precursor protein. Instead, ΔΨ may contribute the precursor unfolding by holding the presequence at the inner membrane for trapping of the unfolded species by the import motor system.
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Affiliation(s)
- Takehiro K Sato
- Department of Chemistry, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya, 464-8602, Japan.,Spiber Inc. 234-1 Mizukami, Kakuganji, Tsuruoka, Yamagata, 997-0052, Japan
| | - Shin Kawano
- Department of Chemistry, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya, 464-8602, Japan.,Faculty of Life Sciences, Kyoto Sangyo University, Kamigamo-motoyama, Kita-ku, Kyoto, 603-8555, Japan.,Institute for Protein Dynamics, Kyoto Sangyo University, Kamigamo-motoyama, Kita-ku, Kyoto, 603-8555, Japan
| | - Toshiya Endo
- Department of Chemistry, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya, 464-8602, Japan. .,Faculty of Life Sciences, Kyoto Sangyo University, Kamigamo-motoyama, Kita-ku, Kyoto, 603-8555, Japan. .,Institute for Protein Dynamics, Kyoto Sangyo University, Kamigamo-motoyama, Kita-ku, Kyoto, 603-8555, Japan.
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8
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Ganesan I, Shi LX, Labs M, Theg SM. Evaluating the Functional Pore Size of Chloroplast TOC and TIC Protein Translocons: Import of Folded Proteins. THE PLANT CELL 2018; 30:2161-2173. [PMID: 30104404 PMCID: PMC6181021 DOI: 10.1105/tpc.18.00427] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Revised: 07/10/2018] [Accepted: 08/10/2018] [Indexed: 05/20/2023]
Abstract
The degree of residual structure retained by proteins while passing through biological membranes is a fundamental mechanistic question of protein translocation. Proteins are generally thought to be unfolded while transported through canonical proteinaceous translocons, including the translocons of the outer and inner chloroplast envelope membranes (TOC and TIC). Here, we readdressed the issue and found that the TOC/TIC translocons accommodated the tightly folded dihydrofolate reductase (DHFR) protein in complex with its stabilizing ligand, methotrexate (MTX). We employed a fluorescein-conjugated methotrexate (FMTX), which has slow membrane transport rates relative to unconjugated MTX, to show that the rate of ligand accumulation inside chloroplasts is faster when bound to DHFR that is actively being imported. Stromal accumulation of FMTX is ATP dependent when DHFR is actively being imported but is otherwise ATP independent, again indicating DHFR/FMTX complex import. Furthermore, the TOC/TIC pore size was probed with fixed-diameter particles and found to be greater than 25.6 Å, large enough to support folded DHFR import and also larger than mitochondrial and bacterial protein translocons that have a requirement for protein unfolding. This unique pore size and the ability to import folded proteins have critical implications regarding the structure and mechanism of the TOC/TIC translocons.
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Affiliation(s)
- Iniyan Ganesan
- Department of Plant Biology, University of California, Davis, California 95616
| | - Lan-Xin Shi
- Department of Plant Biology, University of California, Davis, California 95616
| | - Mathias Labs
- Department of Plant Biology, University of California, Davis, California 95616
| | - Steven M Theg
- Department of Plant Biology, University of California, Davis, California 95616
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9
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Cotranslocational processing of the protein substrate calmodulin by an AAA+ unfoldase occurs via unfolding and refolding intermediates. Proc Natl Acad Sci U S A 2018; 115:E4786-E4795. [PMID: 29735657 DOI: 10.1073/pnas.1721811115] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Protein remodeling by AAA+ enzymes is central for maintaining proteostasis in a living cell. However, a detailed structural description of how this is accomplished at the level of the substrate molecules that are acted upon is lacking. Here, we combine chemical cross-linking and methyl transverse relaxation-optimized NMR spectroscopy to study, at atomic resolution, the stepwise unfolding and subsequent refolding of the two-domain substrate calmodulin by the VAT AAA+ unfoldase from Thermoplasma acidophilum By engineering intermolecular disulphide bridges between the substrate and VAT we trap the substrate at different stages of translocation, allowing structural studies throughout the translocation process. Our results show that VAT initiates substrate translocation by pulling on intrinsically unstructured N or C termini of substrate molecules without showing specificity for a particular amino acid sequence. Although the B1 domain of protein G is shown to unfold cooperatively, translocation of calmodulin leads to the formation of intermediates, and these differ on an individual domain level in a manner that depends on whether pulling is from the N or C terminus. The approach presented generates an atomic resolution picture of substrate unfolding and subsequent refolding by unfoldases that can be quite different from results obtained via in vitro denaturation experiments.
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10
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Sriramoju MK, Chen Y, Lee YTC, Hsu STD. Topologically knotted deubiquitinases exhibit unprecedented mechanostability to withstand the proteolysis by an AAA+ protease. Sci Rep 2018; 8:7076. [PMID: 29728659 PMCID: PMC5935755 DOI: 10.1038/s41598-018-25470-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Accepted: 04/23/2018] [Indexed: 01/03/2023] Open
Abstract
More than one thousand knotted protein structures have been identified so far, but the functional roles of these knots remain elusive. It has been postulated that backbone entanglement may provide additional mechanostability. Here, we employed a bacterial proteasome, ClpXP, to mechanically unfold 52-knotted human ubiquitin C-terminal hydrolase (UCH) paralogs from their C-termini, followed by processive translocation into the proteolytic chamber for degradation. Our results revealed unprecedentedly slow kinetics of ClpXP-mediated proteolysis for the proteasome-associated UCHL5: ten thousand times slower than that of a green fluorescence protein (GFP), which has a comparable size to the UCH domain but much higher chemical and thermal stabilities. The ClpXP-dependent mechanostability positively correlates with the intrinsic unfolding rates of the substrates, spanning over several orders of magnitude for the UCHs. The broad range of mechanostability within the same protein family may be associated with the functional requirements for their differential malleabilities.
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Affiliation(s)
| | - Yen Chen
- Institute of Biological Chemistry, Academia Sinica, Taipei, 11529, Taiwan
| | - Yun-Tzai Cloud Lee
- Institute of Biological Chemistry, Academia Sinica, Taipei, 11529, Taiwan.,Institute of Biochemical Sciences, National Taiwan University, Taipei, 106, Taiwan
| | - Shang-Te Danny Hsu
- Institute of Biological Chemistry, Academia Sinica, Taipei, 11529, Taiwan. .,Institute of Biochemical Sciences, National Taiwan University, Taipei, 106, Taiwan.
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11
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Baker CA, Schudel B, Chaudhari MI, Wu K, Dunford D, Singh AK, Rempe SB, Hatch AV. Nanoporous Hydrogels for the Observation of Anthrax Exotoxin Translocation Dynamics. ACS APPLIED MATERIALS & INTERFACES 2018; 10:13342-13349. [PMID: 29595948 DOI: 10.1021/acsami.8b01871] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The ability to observe lethal anthrax exotoxins translocating through size-constricting nanopores in vitro, combined with detailed sequence and structural data, has aided in elucidated mechanisms of exotoxin cell entry and toxicity. However, due to limited observations of anthrax exotoxins translocating through protective antigen nanopores in vitro and the instability of protective antigen-functionalized suspended lipid bilayers, questions remain regarding the native mechanisms of cell entry. Nanoporous hydrogel membranes offer a robust tool for studying protein translocation with ensemble measurements that complement conventional single-molecule translocation measurements. Here, we utilize nanoporous hydrogel membranes to assess the translocation of full-length anthrax lethal and edema factors through nanopores similar in diameter to protective antigen translocons. We find that, relative to globular serum and other proteins that do not translocate natively through nanopores, anthrax exotoxins demonstrate significantly reduced barriers to pore entry. Computed free-energy barriers to the unfolding of proteins and the dissociation of macromolecular complexes are generally found to coincide with translocation. Finally, a nanopore-blocking strategy is developed that utilizes nonspecific synthetic peptide constructs and effectively prevents LF translocation within the nanoporous hydrogel.
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Affiliation(s)
- Christopher A Baker
- Department of Chemistry , University of Tennessee , Knoxville , Tennessee 37996 , United States
| | - Ben Schudel
- Natera , San Carlos , California 94070 , United States
| | - Mangesh I Chaudhari
- Center for Biological and Engineering Sciences , Sandia National Laboratories , Albuquerque , New Mexico 87185 , United States
| | - Kerrie Wu
- Massachusetts Institute of Technology , Cambridge , Massachusetts 02129 , United States
| | - Derek Dunford
- University of Utah , Salt Lake City , Utah 84112 , United States
| | - Anup K Singh
- Center for Biological and Engineering Sciences , Sandia National Laboratories , Albuquerque , New Mexico 87185 , United States
| | - Susan B Rempe
- Center for Biological and Engineering Sciences , Sandia National Laboratories , Albuquerque , New Mexico 87185 , United States
| | - Anson V Hatch
- Center for Biological and Engineering Sciences , Sandia National Laboratories , Albuquerque , New Mexico 87185 , United States
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12
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Backes S, Hess S, Boos F, Woellhaf MW, Gödel S, Jung M, Mühlhaus T, Herrmann JM. Tom70 enhances mitochondrial preprotein import efficiency by binding to internal targeting sequences. J Cell Biol 2018; 217:1369-1382. [PMID: 29382700 PMCID: PMC5881500 DOI: 10.1083/jcb.201708044] [Citation(s) in RCA: 97] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Revised: 12/12/2017] [Accepted: 01/17/2018] [Indexed: 11/22/2022] Open
Abstract
N-terminal matrix-targeting signals (MTSs) are critical for mitochondrial protein import. Backes et al. identified additional internal MTS-like sequences scattered along the sequences of mitochondrial proteins. By binding to Tom70 on the mitochondrial surface, these sequences support the import process. The biogenesis of mitochondria depends on the import of hundreds of preproteins. N-terminal matrix-targeting signals (MTSs) direct preproteins to the surface receptors Tom20, Tom22, and Tom70. In this study, we show that many preproteins contain additional internal MTS-like signals (iMTS-Ls) in their mature region that share the characteristic properties of presequences. These features allow the in silico prediction of iMTS-Ls. Using Atp1 as model substrate, we show that iMTS-Ls mediate the binding to Tom70 and have the potential to target the protein to mitochondria if they are presented at its N terminus. The import of preproteins with high iMTS-L content is significantly impaired in the absence of Tom70, whereas preproteins with low iMTS-L scores are less dependent on Tom70. We propose a stepping stone model according to which the Tom70-mediated interaction with internal binding sites improves the import competence of preproteins and increases the efficiency of their translocation into the mitochondrial matrix.
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Affiliation(s)
- Sandra Backes
- Cell Biology, University of Kaiserslautern, Kaiserslautern, Germany
| | - Steffen Hess
- Cell Biology, University of Kaiserslautern, Kaiserslautern, Germany
| | - Felix Boos
- Cell Biology, University of Kaiserslautern, Kaiserslautern, Germany
| | | | - Sabrina Gödel
- Computational Systems Biology, University of Kaiserslautern, Kaiserslautern, Germany
| | - Martin Jung
- Medical Biochemistry, Saarland University, Homburg, Germany
| | - Timo Mühlhaus
- Computational Systems Biology, University of Kaiserslautern, Kaiserslautern, Germany
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13
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Elosegui-Artola A, Andreu I, Beedle AE, Lezamiz A, Uroz M, Kosmalska AJ, Oria R, Kechagia JZ, Rico-Lastres P, Le Roux AL, Shanahan CM, Trepat X, Navajas D, Garcia-Manyes S, Roca-Cusachs P. Force Triggers YAP Nuclear Entry by Regulating Transport across Nuclear Pores. Cell 2017; 171:1397-1410.e14. [DOI: 10.1016/j.cell.2017.10.008] [Citation(s) in RCA: 519] [Impact Index Per Article: 74.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Revised: 08/14/2017] [Accepted: 10/04/2017] [Indexed: 12/28/2022]
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14
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Towards the development of an enzyme replacement therapy for the metabolic disorder propionic acidemia. Mol Genet Metab Rep 2016; 8:51-60. [PMID: 27504265 PMCID: PMC4968140 DOI: 10.1016/j.ymgmr.2016.06.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Revised: 06/30/2016] [Accepted: 06/30/2016] [Indexed: 12/11/2022] Open
Abstract
Propionic acidemia (PA) is a life-threatening disease caused by the deficiency of a mitochondrial biotin-dependent enzyme known as propionyl coenzyme-A carboxylase (PCC). This enzyme is responsible for degrading the metabolic intermediate, propionyl coenzyme-A (PP-CoA), derived from multiple metabolic pathways. Currently, except for drastic surgical and dietary intervention that can only provide partial symptomatic relief, no other form of therapeutic option is available for this genetic disorder. Here, we examine a novel approach in protein delivery by specifically targeting and localizing our protein candidate of interest into the mitochondrial matrix of the cells. In order to test this concept of delivery, we have utilized cell penetrating peptides (CPPs) and mitochondria targeting sequences (MTS) to form specific fusion PCC protein, capable of translocating and localizing across cell membranes. In vitro delivery of our candidate fusion proteins, evaluated by confocal images and enzymatic activity assay, indicated effectiveness of this strategy. Therefore, it holds immense potential in creating a new paradigm in site-specific protein delivery and enzyme replacement therapeutic for PA.
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Key Words
- CPPs, cell penetrating peptides
- CoA, coenzyme-A
- ERT, enzyme replacement therapy
- Enzyme replacement therapy
- His-tag, six histidines tag
- LAD, lipoamine dehydrogenase
- MPP, mitochondrial processing peptidase
- MTS, mitochondria targeting sequences
- Mitochondrial targeting sequences
- PA, propionic acidemia
- PCC, propionyl coenzyme-A carboxylase
- PCCA, PCCα subunit
- PCCB, PCCβ subunit
- PP-CoA, propionyl coenzyme-A
- Propionic acidemia
- Propionyl coenzyme-A carboxylase
- Protein transduction domains
- UPLC-MS/MS, ultra performance liquid chromatography tandem mass spectrometry
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15
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Oroz J, Bruix M, Laurents D, Galera-Prat A, Schönfelder J, Cañada F, Carrión-Vázquez M. The Y9P Variant of the Titin I27 Module: Structural Determinants of Its Revisited Nanomechanics. Structure 2016; 24:606-616. [DOI: 10.1016/j.str.2016.02.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Revised: 11/30/2015] [Accepted: 02/22/2016] [Indexed: 11/28/2022]
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16
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Szymczak P. Periodic forces trigger knot untying during translocation of knotted proteins. Sci Rep 2016; 6:21702. [PMID: 26996878 PMCID: PMC4800218 DOI: 10.1038/srep21702] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Accepted: 01/29/2016] [Indexed: 11/19/2022] Open
Abstract
Proteins need to be unfolded when translocated through the pores in mitochondrial and other cellular membranes. Knotted proteins, however, might get stuck during this process, jamming the pore, since the diameter of the pore is smaller than the size of maximally tightened knot. The jamming probability dramatically increases as the magnitude of the driving force exceeds a critical value, Fc. In this numerical study, we show that for deep knots Fc lies below the force range over which molecular import motors operate, which suggest that in these cases the knots will tighten and block the pores. Next, we show how such topological traps might be prevented by using a pulling protocol of a repetitive, on-off character. Such a repetitive pulling is biologically relevant, since the mitochondrial import motor, like other molecular motors transforms chemical energy into directed motions via nucleotide-hydrolysis-mediated conformational changes, which are cyclic in character.
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Affiliation(s)
- Piotr Szymczak
- Institute of Theoretical Physics, Faculty of Physics, University of Warsaw, Warsaw, Poland
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17
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Wojciechowski M, Szymczak P, Carrión-Vázquez M, Cieplak M. Protein unfolding by biological unfoldases: insights from modeling. Biophys J 2015; 107:1661-8. [PMID: 25296319 DOI: 10.1016/j.bpj.2014.07.035] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Revised: 06/09/2014] [Accepted: 07/15/2014] [Indexed: 10/24/2022] Open
Abstract
The molecular determinants of the high efficiency of biological machines like unfoldases (e.g., the proteasome) are not well understood. We propose a model to study protein translocation into the chamber of biological unfoldases represented as a funnel. It is argued that translocation is a much faster way of unfolding a protein than end-to-end stretching, especially in a low-force regime, because it allows for a conformational freedom while concentrating local tension on consecutive regions of a protein chain and preventing refolding. This results in a serial unfolding of the protein structures dominated by unzipping. Thus, pulling against the unfoldase pore is an efficient catalyst of the unfolding reaction. We also show that the presence of the funnel makes the tension along the backbone of the substrate protein nonuniform even when the protein gets unfolded. Hence, the stalling force measured by single-molecule force spectroscopy techniques may be smaller than the traction force of the unfoldase motor.
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Affiliation(s)
| | - Piotr Szymczak
- Institute of Theoretical Physics, Faculty of Physics, University of Warsaw, Warsaw, Poland
| | - Mariano Carrión-Vázquez
- Instituto Cajal, Consejo Superior de Investigaciones Cientificas and Instituto Madrileño de Estudios Avanzados en Nanociencia, Madrid, Spain
| | - Marek Cieplak
- Institute of Physics, Polish Academy of Sciences, Warsaw, Poland.
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18
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Rodriguez-Larrea D, Bayley H. Protein co-translocational unfolding depends on the direction of pulling. Nat Commun 2014; 5:4841. [PMID: 25197784 PMCID: PMC4164780 DOI: 10.1038/ncomms5841] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Accepted: 07/29/2014] [Indexed: 11/21/2022] Open
Abstract
Protein unfolding and translocation through pores occurs during trafficking between organelles, protein degradation and bacterial toxin delivery. In vivo, co-translocational unfolding can be affected by the end of the polypeptide that is threaded into the pore first. Recently, we have shown that co-translocational unfolding can be followed in a model system at the single-molecule level, thereby unravelling molecular steps and their kinetics. Here, we show that the unfolding kinetics of the model substrate thioredoxin, when pulled through an α-haemolysin pore, differ markedly depending on whether the process is initiated from the C terminus or the N terminus. Further, when thioredoxin is pulled from the N terminus, the unfolding pathway bifurcates: some molecules finish unfolding quickly, while others finish ~100 times slower. Our findings have important implications for the understanding of biological unfolding mechanisms and in the application of nanopore technology for the detection of proteins and their modifications. Protein unfolding and translocation through membrane pores occurs in several biological processes and has implications in nanopore technologies. Here, the authors show that the kinetics of unfolding differ depending on which end of the chain enters the pore first.
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Affiliation(s)
| | - Hagan Bayley
- Department of Chemistry, University of Oxford, Oxford OX1 3TA, UK
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19
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Taniguchi Y, Kobayashi A, Kawakami M. Mechanical unfolding studies of protein molecules. Biophysics (Nagoya-shi) 2012; 8:51-58. [PMID: 27857607 PMCID: PMC5070453 DOI: 10.2142/biophysics.8.51] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2011] [Accepted: 12/30/2011] [Indexed: 12/31/2022] Open
Abstract
Atomic force microscopy (AFM) enables the pick up of a single protein molecule to apply a mechanical force. This technique, called "force spectroscopy," provides unique information about the intermediates and free energy landscape of the mechanical unfolding of proteins. In this review, we introduce the AFM-based single molecule force spectroscopy of proteins and describe recent studies that answer some fundamental questions such as "is the mechanical resistance of proteins isotropic?", "what is the structure of the transition state in mechanical unfolding?", and "is mechanical unfolding related to biological functions?"
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Affiliation(s)
- Yukinori Taniguchi
- School of Materials Science, Japan Advanced Institute of Science and Technology (JAIST), 1-1 Asahidai, Nomi, Ishikawa Prefecture 923-1292, Japan
| | - Akiko Kobayashi
- School of Materials Science, Japan Advanced Institute of Science and Technology (JAIST), 1-1 Asahidai, Nomi, Ishikawa Prefecture 923-1292, Japan
| | - Masaru Kawakami
- School of Materials Science, Japan Advanced Institute of Science and Technology (JAIST), 1-1 Asahidai, Nomi, Ishikawa Prefecture 923-1292, Japan
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20
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Schleiff E, Becker T. Common ground for protein translocation: access control for mitochondria and chloroplasts. Nat Rev Mol Cell Biol 2010; 12:48-59. [DOI: 10.1038/nrm3027] [Citation(s) in RCA: 200] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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21
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Yagawa K, Yamano K, Oguro T, Maeda M, Sato T, Momose T, Kawano S, Endo T. Structural basis for unfolding pathway-dependent stability of proteins: vectorial unfolding versus global unfolding. Protein Sci 2010; 19:693-702. [PMID: 20095049 DOI: 10.1002/pro.346] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Point mutations in proteins can have different effects on protein stability depending on the mechanism of unfolding. In the most interesting case of I27, the Ig-like module of the muscle protein titin, one point mutation (Y9P) yields opposite effects on protein stability during denaturant-induced "global unfolding" versus "vectorial unfolding" by mechanical pulling force or cellular unfolding systems. Here, we assessed the reason for the different effects of the Y9P mutation of I27 on the overall molecular stability and N-terminal unraveling by NMR. We found that the Y9P mutation causes a conformational change that is transmitted through beta-sheet structures to reach the central hydrophobic core in the interior and alters its accessibility to bulk solvent, which leads to destabilization of the hydrophobic core. On the other hand, the Y9P mutation causes a bend in the backbone structure, which leads to the formation of a more stable N-terminal structure probably through enhanced hydrophobic interactions.
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Affiliation(s)
- Keisuke Yagawa
- Department of Chemistry, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya 464-8602, Japan
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22
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Chloroplast Import Signals: The Length Requirement for Translocation In Vitro and In Vivo. J Mol Biol 2010; 402:510-23. [DOI: 10.1016/j.jmb.2010.07.052] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2010] [Revised: 07/16/2010] [Accepted: 07/26/2010] [Indexed: 11/24/2022]
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23
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Shokolenko IN, Alexeyev MF, LeDoux SP, Wilson GL. The approaches for manipulating mitochondrial proteome. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2010; 51:451-461. [PMID: 20544885 PMCID: PMC3249350 DOI: 10.1002/em.20570] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Over the past decade a large volume of research data has accumulated which has established a fundamental role for mitochondria in normal cellular functioning, as well as in various pathologies. Mitochondria play a pivotal role in metabolism and energy production, and are one of the key players involved in programmed cell death. On the other hand, mitochondrial dysfunction is implicated, directly or indirectly in numerous pathological conditions including inherited mitochondrial disorders, diabetes, cardiovascular and neurodegenerative diseases, and a variety of malignancies. The ability to modulate mitochondrial function by altering the diverse protein component of this organelle may be of great value for developing future therapeutic interventions. This review will discuss approaches used to introduce proteins into mitochondria. One group of methods utilizes strategies aimed at expressing proteins from genes in the nucleus. These include overexpression of nuclear-encoded mitochondrial proteins, allotopic expression, which is the re-coding and relocation of mitochondrial genes to the nucleus for expression and subsequent delivery of their gene products to mitochondria, and xenotopic expression, which is the nuclear expression of genes coding electron transport chain components from distant species, for delivery of their products to mammalian mitochondria. Additionally, antigenomic and progenomic strategies which focus on expression of mitochondrially targeted nuclear proteins involved in the maintenance of mtDNA will be discussed. The second group of methods considered will focus on attempts to use purified proteins for mitochondrial delivery. Special consideration has been given to the complexities involved in targeting exogenous proteins to mitochondria.
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24
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Ruprecht M, Bionda T, Sato T, Sommer MS, Endo T, Schleiff E. On the impact of precursor unfolding during protein import into chloroplasts. MOLECULAR PLANT 2010; 3:499-508. [PMID: 20118182 DOI: 10.1093/mp/ssp116] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Protein translocation across membranes is a fundamental cellular process. The majority of the proteins of organelles such as mitochondria and chloroplasts is synthesized in the cytosol and subsequently imported in a post-translational manner. The precursor proteins have to be unfolded at least for translocation, but it has also been assumed that they are unfolded during transport to the organelle in the cytosol. Unfolding is governed by chaperones and the translocon itself. At the same time, chaperones provide the energy for the import process. The energetic properties of the chloroplast translocon were studied by import of the Ig-like module of the muscle protein titin fused to the transit peptide of the chloroplast targeted oxygen evolving complex subunit of 33 kDa (OE33). Our results suggest that p(OE33)titin is folded prior to import and that translocation is initiated by unfolding after having bound to the translocon at the chloroplast surface. Using a set of stabilizing and destabilizing mutants of titin previously analyzed by atomic force microscopy and as passenger for mitochondrial translocation, we studied the unfolding force provided by the chloroplast translocon. Based on these results, a model for translocation is discussed.
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Affiliation(s)
- Maike Ruprecht
- Goethe University, Cluster of Excellence Macromolecular Complexes, Centre of Membrane Proteomics, Department of Biosciences, Molecular Cell Biology of Plants, Max-von-Laue Str. 9, D-60438 Frankfurt, Germany
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25
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Artyukhov VG, Kovaleva TA, Kholyavka MG, Bityutskaya LA, Grechkina MV, Obraztsova TB. Study of the oligomeric structure and some physicochemical properties of inulinase from Kluyveromyces marxianus Y-303. Biophysics (Nagoya-shi) 2010. [DOI: 10.1134/s0006350909060025] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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26
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Chng CP, Kitao A. Mechanical unfolding of bacterial flagellar filament protein by molecular dynamics simulation. J Mol Graph Model 2009; 28:548-54. [PMID: 20044289 DOI: 10.1016/j.jmgm.2009.11.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2009] [Accepted: 11/30/2009] [Indexed: 01/03/2023]
Abstract
Bacterial flagellum is a nano-scale motility device constructed by self-assembly. During construction of the cell-exterior filament (the 'propeller'), subunit proteins (called flagellin) are thought to be exported through the hollow flagellum to the growing filament tip in an unfolded state. To gain insight into the unfolded state preceding any force-spectroscopy experiments on flagellin, we employed force-probe molecular dynamics simulations. Two schemes to attain an unfolded state suitable for efficient transport were examined: (i) stretching flagellin along its length; (ii) unzipping flagellin from its adjacently placed termini. Atomic-level unfolding pathways and the mechanical efforts involved under each scheme were obtained for the four-domain flagellin from S. typhimurium. Flagellin appeared stiffer and required larger unfolding forces when stretched as the relative sliding of beta-strands require the breaking of multiple hydrogen bonds at once. In contrast, unzipping requires lower unfolding forces as it mainly involves unraveling beta-sheets by breaking hydrogen bonds one by one.
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Affiliation(s)
- Choon-Peng Chng
- Department of Computational Biology, Graduate School of Frontier Sciences, University of Tokyo, Japan
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27
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Yamamoto H, Fukui K, Takahashi H, Kitamura S, Shiota T, Terao K, Uchida M, Esaki M, Nishikawa SI, Yoshihisa T, Yamano K, Endo T. Roles of Tom70 in import of presequence-containing mitochondrial proteins. J Biol Chem 2009; 284:31635-46. [PMID: 19767391 DOI: 10.1074/jbc.m109.041756] [Citation(s) in RCA: 84] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Mitochondrial protein traffic requires precise recognition of the mitochondrial targeting signals by the import receptors on the mitochondrial surface including a general import receptor Tom20 and a receptor for presequence-less proteins, Tom70. Here we took a proteome-wide approach of mitochondrial protein import in vitro to find a set of presequence-containing precursor proteins for recognition by Tom70. The presequences of the Tom70-dependent precursor proteins were recognized by Tom20, whereas their mature parts exhibited Tom70-dependent import when attached to the presequence of Tom70-independent precursor proteins. The mature parts of the Tom70-dependent precursor proteins have the propensity to aggregate, and the presence of the receptor domain of Tom70 prevents their aggregate formation. Therefore Tom70 plays the role of a docking site for not only cytosolic chaperones but also aggregate-prone substrates to maintain their solubility for efficient transfer to downstream components of the mitochondrial import machineries.
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Affiliation(s)
- Hayashi Yamamoto
- Department of Chemistry, Graduate School of Science, Japan Science and Technology Agency, Research Centre for Material Science, Nagoya University, Chikusa-ku, Nagoya 464-8602, Japan
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28
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Tamura Y, Endo T, Iijima M, Sesaki H. Ups1p and Ups2p antagonistically regulate cardiolipin metabolism in mitochondria. ACTA ACUST UNITED AC 2009; 185:1029-45. [PMID: 19506038 PMCID: PMC2711612 DOI: 10.1083/jcb.200812018] [Citation(s) in RCA: 131] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Cardiolipin, a unique phospholipid composed of four fatty acid chains, is located mainly in the mitochondrial inner membrane (IM). Cardiolipin is required for the integrity of several protein complexes in the IM, including the TIM23 translocase, a dynamic complex which mediates protein import into the mitochondria through interactions with the import motor presequence translocase–associated motor (PAM). In this study, we report that two homologous intermembrane space proteins, Ups1p and Ups2p, control cardiolipin metabolism and affect the assembly state of TIM23 and its association with PAM in an opposing manner. In ups1Δ mitochondria, cardiolipin levels were decreased, and the TIM23 translocase showed altered conformation and decreased association with PAM, leading to defects in mitochondrial protein import. Strikingly, loss of Ups2p restored normal cardiolipin levels and rescued TIM23 defects in ups1Δ mitochondria. Furthermore, we observed synthetic growth defects in ups mutants in combination with loss of Pam17p, which controls the integrity of PAM. Our findings provide a novel molecular mechanism for the regulation of cardiolipin metabolism.
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Affiliation(s)
- Yasushi Tamura
- Department of Cell Biology, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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29
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Koodathingal P, Jaffe NE, Kraut DA, Prakash S, Fishbain S, Herman C, Matouschek A. ATP-dependent proteases differ substantially in their ability to unfold globular proteins. J Biol Chem 2009; 284:18674-84. [PMID: 19383601 DOI: 10.1074/jbc.m900783200] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
ATP-dependent proteases control the concentrations of hundreds of regulatory proteins and remove damaged or misfolded proteins from cells. They select their substrates primarily by recognizing sequence motifs or covalent modifications. Once a substrate is bound to the protease, it has to be unfolded and translocated into the proteolytic chamber to be degraded. Some proteases appear to be promiscuous, degrading substrates with poorly defined targeting signals, which suggests that selectivity may be controlled at additional levels. Here we compare the abilities of representatives from all classes of ATP-dependent proteases to unfold a model substrate protein and find that the unfolding abilities range over more than 2 orders of magnitude. We propose that these differences in unfolding abilities contribute to the fates of substrate proteins and may act as a further layer of selectivity during protein destruction.
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Affiliation(s)
- Prakash Koodathingal
- Department of Biochemistry, Molecular Biology and Cell Biology, Northwestern University, Evanston, Illinois 60208, USA
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30
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Abstract
The translocation of proteins through pores is central to many biological phenomena, such as mitochondrial protein import, protein degradation, and delivery of protein toxins to their cytosolic targets. Because proteins typically have to pass through constrictions that are too narrow to accommodate folded structures, translocation must be coupled to protein unfolding. The simplest model that accounts for such co-translocational unfolding assumes that both translocation and unfolding are accomplished by pulling on the end of the polypeptide chain mechanically. In this Account, we describe theoretical studies and computer simulations of this model and discuss how the time scales of translocation depend on the pulling force and on the protein structure. Computationally, this is a difficult problem because biologically or experimentally relevant time scales of translocation are typically orders of magnitude slower than those accessible by fully atomistic simulations. For this reason, we explore one-dimensional free energy landscapes along suitably defined translocation coordinates and discuss various approaches to their computation. We argue that the free energy landscape of translocation is often bumpy because confinement partitions the protein's configuration space into distinct basins of attraction separated by large entropic barriers. Favorable protein-pore interactions and nonnative interactions within the protein further contribute to the complexity. Computer simulations and simple scaling estimates show that forces of just 2-6 pN are often sufficient to ensure transport of unstructured polypeptides, whereas much higher forces are typically needed to translocate folded protein domains. The unfolding mechanisms found from simulations of translocation are different from those observed in the much better understood case of atomic force microscopy (AFM) pulling studies, in which proteins are unraveled by stretching them between their N- and C-termini. In contrast to AFM experiments, single-molecule experimental studies of protein translocation have just started to emerge. We describe one example of a collaborative study, in which dwell times of beta-hairpin-forming peptides inside the alpha-hemolysin pore were both measured experimentally and estimated using computer simulations. Analysis of the simulated trajectories has explained the experimental finding that more stable hairpins take, on the average, longer to traverse the pore. Despite the insight we have gained, the general relationship between the structure of proteins and their resistance to mechanically driven co-translocational unfolding remains poorly understood. Future theoretical progress likely will be made in conjunction with single-molecule experiments and will require realistic models to account for specific protein-pore interactions and for solvent effects.
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Affiliation(s)
- Dmitrii E. Makarov
- Department of Chemistry and Biochemistry and Institute for Theoretical Chemistry, the University of Texas at Austin, Austin, Texas, 78712
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31
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Mills M, Andricioaei I. An experimentally guided umbrella sampling protocol for biomolecules. J Chem Phys 2009; 129:114101. [PMID: 19044944 DOI: 10.1063/1.2976440] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We present a simple method for utilizing experimental data to improve the efficiency of numerical calculations of free energy profiles from molecular dynamics simulations. The method involves umbrella sampling simulations with restraining potentials based on a known approximate estimate of the free energy profile derived solely from experimental data. The use of the experimental data results in optimal restraining potentials, guides the simulation along relevant pathways, and decreases overall computational time. In demonstration of the method, two systems are showcased. First, guided, unguided (regular) umbrella sampling simulations and exhaustive sampling simulations are compared to each other in the calculation of the free energy profile for the distance between the ends of a pentapeptide. The guided simulation use restraints based on a simulated "experimental" potential of mean force of the end-to-end distance that would be measured by fluorescence resonance energy transfer (obtained from exhaustive sampling). Statistical analysis shows a dramatic improvement in efficiency for a 5 window guided umbrella sampling over 5 and 17 window unguided umbrella sampling simulations. Moreover, the form of the potential of mean force for the guided simulations evolves, as one approaches convergence, along the same milestones as the extensive simulations, but exponentially faster. Second, the method is further validated by replicating the forced unfolding pathway of the titin I27 domain using guiding umbrella sampling potentials determined from actual single molecule pulling data. Comparison with unguided umbrella sampling reveals that the use of guided sampling encourages unfolding simulations to converge faster to a forced unfolding pathway that agrees with previous results and produces a more accurate potential of mean force.
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Affiliation(s)
- Maria Mills
- Department of Chemistry, University of California, Irvine, California 92697, USA
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32
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Structural Stabilities of Different Regions of the Titin I27 Domain Contribute Differently to Unfolding upon Mitochondrial Protein Import. J Mol Biol 2009; 385:811-9. [DOI: 10.1016/j.jmb.2008.10.076] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2008] [Revised: 10/21/2008] [Accepted: 10/28/2008] [Indexed: 11/19/2022]
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33
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Yamano K, Kuroyanagi-Hasegawa M, Esaki M, Yokota M, Endo T. Step-size analyses of the mitochondrial Hsp70 import motor reveal the Brownian ratchet in operation. J Biol Chem 2008; 283:27325-32. [PMID: 18678864 DOI: 10.1074/jbc.m805249200] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Newly synthesized mitochondrial precursor proteins have to become unfolded by the mitochondrial Hsp70 (mtHsp70) import motor to cross the mitochondrial membranes. To assess the mechanism of unfolding of precursor proteins by mtHsp70, we designed a system to measure step sizes of the mtHsp70 import motor, which are distances at which the motor system moves along polypeptide chains during a single turnover of ATP. We made a series of fusion proteins consisting of a mitochondrial presequence containing the first mtHsp70 binding site, a spacer sequence containing an Hsp70 avoidance segment followed by the second mtHsp70 binding site, and different folded mature domains. Analyses of the dependence of the import rates of those fusion proteins on the lengths of Hsp70 avoidance segments allowed us to estimate the step sizes, which differ for different mature domains and different lengths of the spacers. These results suggest that the mtHsp70 import motor functions at least as a molecular Brownian ratchet to unfold mitochondrial precursor proteins.
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Affiliation(s)
- Koji Yamano
- Department of Chemistry, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya 464-8602, Japan
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34
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Pastukh V, Shokolenko IN, Wilson GL, Alexeyev MF. Mutations in the passenger polypeptide can affect its partitioning between mitochondria and cytoplasm: mutations can impair the mitochondrial import of DsRed. Mol Biol Rep 2008; 35:215-23. [PMID: 17385058 PMCID: PMC10388708 DOI: 10.1007/s11033-007-9073-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2006] [Accepted: 02/26/2007] [Indexed: 11/29/2022]
Abstract
In this study, we report that the partitioning between mitochondria and cytoplasm of two variants, mCherry and DsRed Express (DRE), of the red fluorescent protein, DsRed, fused to one of the six matrix targeting sequences (MTSs) can be affected by both MTS and amino acid substitutions in DsRed. Of the six MTSs tested, MTSs from superoxide dismutase and DNA polymerase gamma failed to direct mCherry, but not DRE to mitochondria. By evaluating a series of chimeras between mCherry and DRE fused to the MTS of superoxide dismutase, we attribute the differences in the mitochondrial partitioning to differences in the primary amino acid sequence of the passenger polypeptide. The impairment of mitochondrial partitioning closely parallels the number of mCherry-specific mutations, and is not specific to mutations located in any particular region of the polypeptide. These observations suggest that both MTS and the passenger polypeptide affect the efficiency of mitochondrial import and provide a rationale for the observed diversity in the primary amino acid sequences of natural MTSs.
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Affiliation(s)
- Viktoriya Pastukh
- Department of Cell Biology and Neuroscience, University of South Alabama, 307 University Blvd., MSB1201, Mobile, AL 36688, USA
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35
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Diaz F, Moraes CT. Mitochondrial biogenesis and turnover. Cell Calcium 2008; 44:24-35. [PMID: 18395251 DOI: 10.1016/j.ceca.2007.12.004] [Citation(s) in RCA: 101] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2007] [Revised: 12/10/2007] [Accepted: 12/12/2007] [Indexed: 11/17/2022]
Abstract
Mitochondrial biogenesis is a complex process involving the coordinated expression of mitochondrial and nuclear genes, the import of the products of the latter into the organelle and turnover. The mechanisms associated with these events have been intensively studied in the last 20 years and our understanding of their details is much improved. Mitochondrial biogenesis requires the participation of calcium signaling that activates a series of calcium-dependent protein kinases that in turn activate transcription factors and coactivators such as PGC-1alpha that regulates the expression of genes coding for mitochondrial components. In addition, mitochondrial biogenesis involves the balance of mitochondrial fission-fusion. Mitochondrial malfunction or defects in any of the many pathways involved in mitochondrial biogenesis can lead to degenerative diseases and possibly play an important part in aging.
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Affiliation(s)
- Francisca Diaz
- Department of Neurology, University of Miami, Miller School of Medicine, 1095 NW 14th Terrace, Miami, FL 33136, USA.
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36
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Bolender N, Sickmann A, Wagner R, Meisinger C, Pfanner N. Multiple pathways for sorting mitochondrial precursor proteins. EMBO Rep 2008; 9:42-9. [PMID: 18174896 DOI: 10.1038/sj.embor.7401126] [Citation(s) in RCA: 241] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2007] [Accepted: 10/18/2007] [Indexed: 11/09/2022] Open
Abstract
Mitochondria import hundreds of different precursor proteins from the cytosol. More than 50% of mitochondrial proteins do not use the classical import pathway that is guided by amino-terminal presequences, but instead contain different types of internal targeting signals. Recent studies have revealed an unexpected complexity of the mitochondrial protein import machinery and have led to the discovery of new transport pathways. Here, we review the versatility of mitochondrial protein import and its connection to mitochondrial morphology, redox regulation and energetics.
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Affiliation(s)
- Natalia Bolender
- Institut für Biochemie und Molekularbiologie, Zentrum für Biochemie und Molekulare Zellforschung, Universität Freiburg, Germany
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Oberhauser AF, Carrión-Vázquez M. Mechanical biochemistry of proteins one molecule at a time. J Biol Chem 2008; 283:6617-21. [PMID: 18195002 DOI: 10.1074/jbc.r700050200] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The activity of proteins and their complexes often involves the conversion of chemical energy (stored or supplied) into mechanical work through conformational changes. Mechanical forces are also crucial for the regulation of the structure and function of cells and tissues. Thus, the shape of eukaryotic cells (and by extension, that of the multicellular organisms they form) is the result of cycles of mechanosensing, mechanotransduction, and mechanoresponse. Recently developed single-molecule atomic force microscopy techniques can be used to manipulate single molecules, both in real time and under physiological conditions, and are ideally suited to directly quantify the forces involved in both intra- and intermolecular protein interactions. In combination with molecular biology and computer simulations, these techniques have been applied to characterize the unfolding and refolding reactions in a variety of proteins. Single-molecule mechanical techniques are providing fundamental information on the structure and function of proteins and are becoming an indispensable tool to understand how these molecules fold and work.
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Affiliation(s)
- Andres F Oberhauser
- Department of Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, Texas 77555, USA.
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38
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Abstract
About 10% to 15% of the nuclear genes of eukaryotic organisms encode mitochondrial proteins. These proteins are synthesized in the cytosol and recognized by receptors on the surface of mitochondria. Translocases in the outer and inner membrane of mitochondria mediate the import and intramitochondrial sorting of these proteins; ATP and the membrane potential are used as energy sources. Chaperones and auxiliary factors assist in the folding and assembly of mitochondrial proteins into their native, three-dimensional structures. This review summarizes the present knowledge on the import and sorting of mitochondrial precursor proteins, with a special emphasis on unresolved questions and topics of current research.
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Affiliation(s)
- Walter Neupert
- Institut für Physiologische Chemie, Universität München, 81377 München, Germany.
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Valle F, Sandal M, Samorì B. The interplay between chemistry and mechanics in the transduction of a mechanical signal into a biochemical function. Phys Life Rev 2007. [DOI: 10.1016/j.plrev.2007.06.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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40
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Nouwen N, Berrelkamp G, Driessen AJM. Bacterial sec-translocase unfolds and translocates a class of folded protein domains. J Mol Biol 2007; 372:422-33. [PMID: 17669421 DOI: 10.1016/j.jmb.2007.07.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2007] [Revised: 06/03/2007] [Accepted: 07/03/2007] [Indexed: 10/23/2022]
Abstract
It is generally assumed that preprotein substrates must be presented in an unfolded state to the bacterial Sec-translocase in order to be translocated. Here, we have examined the ability of the Sec-translocase to translocate folded preproteins. Tightly folded human cardiac Ig-like domain I27 fused to the C terminus of proOmpA is translocated efficiently by the Sec-translocase and the translocation kinetics are determined by the extent of folding of the titin I27 domain. Accumulation of specific translocation intermediates around the fusion point that undergo translocation progress upon ATP binding suggests that the motor protein SecA plays an important and decisive role in promoting unfolding of the titin I27 domain. It is concluded that the bacterial Sec-translocase is capable of actively unfolding preproteins.
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Affiliation(s)
- Nico Nouwen
- Department of Molecular Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute and the Materials Science Center Plus, University of Groningen, 9751 NN, Haren, The Netherlands
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41
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Tomkiewicz D, Nouwen N, Driessen AJM. Pushing, pulling and trapping--modes of motor protein supported protein translocation. FEBS Lett 2007; 581:2820-8. [PMID: 17466297 DOI: 10.1016/j.febslet.2007.04.015] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2007] [Revised: 04/01/2007] [Accepted: 04/11/2007] [Indexed: 11/19/2022]
Abstract
Protein translocation across the cellular membranes is an ubiquitous and crucial activity of cells. This process is mediated by translocases that consist of a protein conducting channel and an associated motor protein. Motor proteins interact with protein substrates and utilize the free energy of ATP binding and hydrolysis for protein unfolding, translocation and unbinding. Since motor proteins are found either at the cis- or trans-side of the membrane, different mechanisms for translocation have been proposed. In the Power stroke model, cis-acting motors are thought to push, while trans-motors pull on the substrate protein during translocation. In the Brownian ratchet model, translocation occurs by diffusion of the unfolded polypeptide through the translocation pore while directionality is achieved by trapping and refolding. Recent insights in the structure and function of the molecular motors suggest that different mechanisms can be employed simultaneously.
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Affiliation(s)
- Danuta Tomkiewicz
- Department of Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Kerklaan 30, 9751 NN Haren, The Netherlands
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42
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Forman JR, Clarke J. Mechanical unfolding of proteins: insights into biology, structure and folding. Curr Opin Struct Biol 2007; 17:58-66. [PMID: 17251000 DOI: 10.1016/j.sbi.2007.01.006] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2006] [Revised: 12/13/2006] [Accepted: 01/12/2007] [Indexed: 10/23/2022]
Abstract
Since user-friendly atomic force microscopes came onto the market a few years ago, scientists have explored the response of many proteins to applied force. This field has now matured beyond the phenomenological with exciting recent developments, particularly with regards to research into biological questions. For example, detailed mechanistic studies have suggested how mechanically active proteins perform their functions. Also, in vitro forced unfolding has been compared with in vivo protein import and degradation. Additionally, investigations have been carried out that probe the relationship between protein structure and response to applied force, an area that has benefited significantly from synergy between experiments and simulations. Finally, recent technological developments offer exciting new avenues for experimental studies.
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Affiliation(s)
- Julia R Forman
- Cambridge University Department of Chemistry, MRC Centre for Protein Engineering, Lensfield Road, Cambridge CB2 1EW, UK
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West DK, Brockwell DJ, Paci E. Prediction of the translocation kinetics of a protein from its mechanical properties. Biophys J 2006; 91:L51-3. [PMID: 16815903 PMCID: PMC1544310 DOI: 10.1529/biophysj.106.089490] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Proteins are actively unfolded to pass through narrow channels in macromolecular complexes that catalyze protein translocation and degradation. Catalyzed unfolding shares many features that characterize the mechanical unfolding of proteins using the atomic force microscope (AFM). However, simulations of unfolding induced by the AFM and when a protein is translocated through a pore suggest that each process occurs by distinct pathways. The link, if any, between each type of unfolding, therefore, is not known. We show that the mechanical unfolding energy landscape of a protein, obtained using an atomistic molecular model, can be used to predict both the relative mechanical strength of proteins when unfolded using the AFM and when unfolded by translocation into a pore. We thus link the two processes and show that the import rate through a pore not only depends on the location of the initiation tag but also on the mechanical properties of the protein when averaged over all the possible geometries that are relevant for a given translocation initiation site.
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Affiliation(s)
- Daniel K West
- School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, United Kingdom
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