1
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Zarges C, Riemer J. Oxidative protein folding in the intermembrane space of human mitochondria. FEBS Open Bio 2024; 14:1610-1626. [PMID: 38867508 PMCID: PMC11452306 DOI: 10.1002/2211-5463.13839] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2024] [Revised: 05/03/2024] [Accepted: 05/23/2024] [Indexed: 06/14/2024] Open
Abstract
The mitochondrial intermembrane space hosts a machinery for oxidative protein folding, the mitochondrial disulfide relay. This machinery imports a large number of soluble proteins into the compartment, where they are retained through oxidative folding. Additionally, the disulfide relay enhances the stability of many proteins by forming disulfide bonds. In this review, we describe the mitochondrial disulfide relay in human cells, its components, and their coordinated collaboration in mechanistic detail. We also discuss the human pathologies associated with defects in this machinery and its protein substrates, providing a comprehensive overview of its biological importance and implications for health.
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Affiliation(s)
| | - Jan Riemer
- Institute for BiochemistryUniversity of CologneGermany
- Cologne Excellence Cluster on Cellular Stress Responses in Aging‐Associated Diseases (CECAD)University of CologneGermany
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2
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Protein delivery to living cells by thermal stimulation for biophysical investigation. Sci Rep 2022; 12:17190. [PMID: 36229511 PMCID: PMC9561116 DOI: 10.1038/s41598-022-21103-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 09/22/2022] [Indexed: 01/05/2023] Open
Abstract
Studying biomolecules in their native environment represents the ideal sample condition for structural biology investigations. Here we present a novel protocol which allows to delivery proteins into eukaryotic cells through a mild thermal stimulation. The data presented herein show the efficacy of this approach for delivering proteins in the intracellular environment of mammalian cells reaching a concentration range suitable for successfully applying biophysical methods, such as double electron electron resonance (DEER) measurements for characterising protein conformations.
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3
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Theillet FX, Luchinat E. In-cell NMR: Why and how? PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2022; 132-133:1-112. [PMID: 36496255 DOI: 10.1016/j.pnmrs.2022.04.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 04/19/2022] [Accepted: 04/27/2022] [Indexed: 06/17/2023]
Abstract
NMR spectroscopy has been applied to cells and tissues analysis since its beginnings, as early as 1950. We have attempted to gather here in a didactic fashion the broad diversity of data and ideas that emerged from NMR investigations on living cells. Covering a large proportion of the periodic table, NMR spectroscopy permits scrutiny of a great variety of atomic nuclei in all living organisms non-invasively. It has thus provided quantitative information on cellular atoms and their chemical environment, dynamics, or interactions. We will show that NMR studies have generated valuable knowledge on a vast array of cellular molecules and events, from water, salts, metabolites, cell walls, proteins, nucleic acids, drugs and drug targets, to pH, redox equilibria and chemical reactions. The characterization of such a multitude of objects at the atomic scale has thus shaped our mental representation of cellular life at multiple levels, together with major techniques like mass-spectrometry or microscopies. NMR studies on cells has accompanied the developments of MRI and metabolomics, and various subfields have flourished, coined with appealing names: fluxomics, foodomics, MRI and MRS (i.e. imaging and localized spectroscopy of living tissues, respectively), whole-cell NMR, on-cell ligand-based NMR, systems NMR, cellular structural biology, in-cell NMR… All these have not grown separately, but rather by reinforcing each other like a braided trunk. Hence, we try here to provide an analytical account of a large ensemble of intricately linked approaches, whose integration has been and will be key to their success. We present extensive overviews, firstly on the various types of information provided by NMR in a cellular environment (the "why", oriented towards a broad readership), and secondly on the employed NMR techniques and setups (the "how", where we discuss the past, current and future methods). Each subsection is constructed as a historical anthology, showing how the intrinsic properties of NMR spectroscopy and its developments structured the accessible knowledge on cellular phenomena. Using this systematic approach, we sought i) to make this review accessible to the broadest audience and ii) to highlight some early techniques that may find renewed interest. Finally, we present a brief discussion on what may be potential and desirable developments in the context of integrative studies in biology.
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Affiliation(s)
- Francois-Xavier Theillet
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France.
| | - Enrico Luchinat
- Dipartimento di Scienze e Tecnologie Agro-Alimentari, Alma Mater Studiorum - Università di Bologna, Piazza Goidanich 60, 47521 Cesena, Italy; CERM - Magnetic Resonance Center, and Neurofarba Department, Università degli Studi di Firenze, 50019 Sesto Fiorentino, Italy
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4
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Luchinat E, Cremonini M, Banci L. Radio Signals from Live Cells: The Coming of Age of In-Cell Solution NMR. Chem Rev 2022; 122:9267-9306. [PMID: 35061391 PMCID: PMC9136931 DOI: 10.1021/acs.chemrev.1c00790] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Indexed: 12/12/2022]
Abstract
A detailed knowledge of the complex processes that make cells and organisms alive is fundamental in order to understand diseases and to develop novel drugs and therapeutic treatments. To this aim, biological macromolecules should ideally be characterized at atomic resolution directly within the cellular environment. Among the existing structural techniques, solution NMR stands out as the only one able to investigate at high resolution the structure and dynamic behavior of macromolecules directly in living cells. With the advent of more sensitive NMR hardware and new biotechnological tools, modern in-cell NMR approaches have been established since the early 2000s. At the coming of age of in-cell NMR, we provide a detailed overview of its developments and applications in the 20 years that followed its inception. We review the existing approaches for cell sample preparation and isotopic labeling, the application of in-cell NMR to important biological questions, and the development of NMR bioreactor devices, which greatly increase the lifetime of the cells allowing real-time monitoring of intracellular metabolites and proteins. Finally, we share our thoughts on the future perspectives of the in-cell NMR methodology.
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Affiliation(s)
- Enrico Luchinat
- Dipartimento
di Scienze e Tecnologie Agro-Alimentari, Alma Mater Studiorum−Università di Bologna, Piazza Goidanich 60, 47521 Cesena, Italy
- Magnetic
Resonance Center, Università degli
Studi di Firenze, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Italy
| | - Matteo Cremonini
- Magnetic
Resonance Center, Università degli
Studi di Firenze, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Italy
| | - Lucia Banci
- Magnetic
Resonance Center, Università degli
Studi di Firenze, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Italy
- Consorzio
Interuniversitario Risonanze Magnetiche di Metallo Proteine, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Italy
- Dipartimento
di Chimica, Università degli Studi
di Firenze, Via della
Lastruccia 3, 50019 Sesto Fiorentino, Italy
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5
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Abstract
In-cell structural biology aims at extracting structural information about proteins or nucleic acids in their native, cellular environment. This emerging field holds great promise and is already providing new facts and outlooks of interest at both fundamental and applied levels. NMR spectroscopy has important contributions on this stage: It brings information on a broad variety of nuclei at the atomic scale, which ensures its great versatility and uniqueness. Here, we detail the methods, the fundamental knowledge, and the applications in biomedical engineering related to in-cell structural biology by NMR. We finally propose a brief overview of the main other techniques in the field (EPR, smFRET, cryo-ET, etc.) to draw some advisable developments for in-cell NMR. In the era of large-scale screenings and deep learning, both accurate and qualitative experimental evidence are as essential as ever to understand the interior life of cells. In-cell structural biology by NMR spectroscopy can generate such a knowledge, and it does so at the atomic scale. This review is meant to deliver comprehensive but accessible information, with advanced technical details and reflections on the methods, the nature of the results, and the future of the field.
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Affiliation(s)
- Francois-Xavier Theillet
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
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6
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Ghosh R, Xiao Y, Kragelj J, Frederick KK. In-Cell Sensitivity-Enhanced NMR of Intact Viable Mammalian Cells. J Am Chem Soc 2021; 143:18454-18466. [PMID: 34724614 DOI: 10.1021/jacs.1c06680] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
NMR has the resolution and specificity to determine atomic-level protein structures of isotopically labeled proteins in complex environments, and with the sensitivity gains conferred by dynamic nuclear polarization (DNP), NMR has the sensitivity to detect proteins at their endogenous concentrations. However, DNP sensitivity enhancements are critically dependent on experimental conditions and sample composition. While some of these conditions are theoretically compatible with cellular viability, the effects of others on cellular sample integrity are unknown. Uncertainty about the integrity of cellular samples limits the utility of experimental outputs of in-cell experiments. Using several measures, we establish conditions that support DNP enhancements that can enable detection of micromolar concentrations of proteins in experimentally tractable times that are compatible with cellular viability. Taken together, we establish DNP-assisted MAS NMR as a technique for structural investigations of biomolecules in intact viable cells that can be phenotyped both before and after NMR experiments.
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Affiliation(s)
- Rupam Ghosh
- Department of Biophysics, UT Southwestern Medical Center, Dallas, Texas 75390-8816, United States
| | - Yiling Xiao
- Department of Biophysics, UT Southwestern Medical Center, Dallas, Texas 75390-8816, United States
| | - Jaka Kragelj
- Department of Biophysics, UT Southwestern Medical Center, Dallas, Texas 75390-8816, United States
| | - Kendra K Frederick
- Department of Biophysics, UT Southwestern Medical Center, Dallas, Texas 75390-8816, United States.,Center for Alzheimer's and Neurodegenerative Disease, UT Southwestern Medical Center, Dallas, Texas 75390, United States
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7
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Murschall LM, Peker E, MacVicar T, Langer T, Riemer J. Protein Import Assay into Mitochondria Isolated from Human Cells. Bio Protoc 2021; 11:e4057. [PMID: 34263000 DOI: 10.21769/bioprotoc.4057] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Revised: 03/29/2021] [Accepted: 04/01/2021] [Indexed: 11/02/2022] Open
Abstract
Mitochondria are essential organelles containing approximately 1,500 proteins. Only approximately 1% of these proteins are synthesized inside mitochondria, whereas the remaining 99% are synthesized as precursors on cytosolic ribosomes and imported into the organelle. Various tools and techniques to analyze the import process have been developed. Among them, in vitro reconstituted import systems are of importance to study these processes in detail. These experiments monitor the import reaction of mitochondrial precursors that were previously radiolabeled in a cell-free environment. However, the methods described have been mostly performed in mitochondria isolated from S. cerevisiae. Here, we describe the adaptation of this powerful assay to import proteins into crude mitochondria isolated from human tissue culture cells. Graphic abstract: Overview of the assay to monitor protein import into mitochondria isolated from human cells.
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Affiliation(s)
- Lena M Murschall
- Institute for Biochemistry, Redox Biochemistry, University of Cologne, Zuelpicher Str. 47a/R. 3.49, 50674 Cologne, Germany
| | - Esra Peker
- Institute for Biochemistry, Redox Biochemistry, University of Cologne, Zuelpicher Str. 47a/R. 3.49, 50674 Cologne, Germany
| | - Thomas MacVicar
- Department of Mitochondrial Proteostasis, Max Planck Institute for Biology of Ageing, 50931 Cologne, Germany
| | - Thomas Langer
- Department of Mitochondrial Proteostasis, Max Planck Institute for Biology of Ageing, 50931 Cologne, Germany.,Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD) and Center for Molecular Medicine (CMMC), University of Cologne, 50931 Cologne, Germany
| | - Jan Riemer
- Institute for Biochemistry, Redox Biochemistry, University of Cologne, Zuelpicher Str. 47a/R. 3.49, 50674 Cologne, Germany.,Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD) and Center for Molecular Medicine (CMMC), University of Cologne, 50931 Cologne, Germany
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8
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Launay H, Shao H, Bornet O, Cantrelle FX, Lebrun R, Receveur-Brechot V, Gontero B. Flexibility of Oxidized and Reduced States of the Chloroplast Regulatory Protein CP12 in Isolation and in Cell Extracts. Biomolecules 2021; 11:biom11050701. [PMID: 34066751 PMCID: PMC8151241 DOI: 10.3390/biom11050701] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 05/03/2021] [Accepted: 05/04/2021] [Indexed: 12/12/2022] Open
Abstract
In the chloroplast, Calvin–Benson–Bassham enzymes are active in the reducing environment created in the light by electrons from the photosystems. In the dark, these enzymes are inhibited, mainly caused by oxidation of key regulatory cysteine residues. CP12 is a small protein that plays a role in this regulation with four cysteine residues that undergo a redox transition. Using amide-proton exchange with solvent, measured by nuclear magnetic resonance (NMR) and mass-spectrometry, we confirmed that reduced CP12 is intrinsically disordered. Using real-time NMR, we showed that the oxidation of the two disulfide bridges is simultaneous. In oxidized CP12, the C23–C31 pair is in a region that undergoes a conformational exchange in the NMR-intermediate timescale. The C66–C75 pair is in the C-terminus that folds into a stable helical turn. We confirmed that these structural states exist in a physiologically relevant environment: a cell extract from Chlamydomonas reinhardtii. Consistent with these structural equilibria, the reduction is slower for the C66–C75 pair than for the C23–C31 pair. The redox mid-potentials for the two cysteine pairs differ and are similar to those found for glyceraldehyde 3-phosphate dehydrogenase and phosphoribulokinase, consistent with the regulatory role of CP12.
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Affiliation(s)
- Helene Launay
- Aix Marseille Univ, CNRS, BIP, UMR7281, F-13402 Marseille, France; (H.S.); (V.R.-B.)
- Correspondence: (H.L.); (B.G.)
| | - Hui Shao
- Aix Marseille Univ, CNRS, BIP, UMR7281, F-13402 Marseille, France; (H.S.); (V.R.-B.)
| | - Olivier Bornet
- NMR Platform, Institut de Microbiologie de la Méditerranée, Aix Marseille Univ, F-13009 Marseille, France;
| | - Francois-Xavier Cantrelle
- CNRS, ERL9002, Integrative Structural Biology, Univ. Lille, F-59658 Lille, France;
- U1167, INSERM, CHU Lille, Institut Pasteur de Lille, F-59019 Lille, France
| | - Regine Lebrun
- Plate-forme Protéomique, Marseille Protéomique (MaP), IMM FR 3479, 31 Chemin Joseph Aiguier, F-13009 Marseille, France;
| | | | - Brigitte Gontero
- Aix Marseille Univ, CNRS, BIP, UMR7281, F-13402 Marseille, France; (H.S.); (V.R.-B.)
- Correspondence: (H.L.); (B.G.)
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9
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CHCHD4 (MIA40) and the mitochondrial disulfide relay system. Biochem Soc Trans 2021; 49:17-27. [PMID: 33599699 PMCID: PMC7925007 DOI: 10.1042/bst20190232] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Revised: 12/19/2020] [Accepted: 01/06/2021] [Indexed: 12/13/2022]
Abstract
Mitochondria are pivotal for normal cellular physiology, as they perform a crucial role in diverse cellular functions and processes, including respiration and the regulation of bioenergetic and biosynthetic pathways, as well as regulating cellular signalling and transcriptional networks. In this way, mitochondria are central to the cell's homeostatic machinery, and as such mitochondrial dysfunction underlies the pathology of a diverse range of diseases including mitochondrial disease and cancer. Mitochondrial import pathways and targeting mechanisms provide the means to transport into mitochondria the hundreds of nuclear-encoded mitochondrial proteins that are critical for the organelle's many functions. One such import pathway is the highly evolutionarily conserved disulfide relay system (DRS) within the mitochondrial intermembrane space (IMS), whereby proteins undergo a form of oxidation-dependent protein import. A central component of the DRS is the oxidoreductase coiled-coil-helix-coiled-coil-helix (CHCH) domain-containing protein 4 (CHCHD4, also known as MIA40), the human homologue of yeast Mia40. Here, we summarise the recent advances made to our understanding of the role of CHCHD4 and the DRS in physiology and disease, with a specific focus on the emerging importance of CHCHD4 in regulating the cellular response to low oxygen (hypoxia) and metabolism in cancer.
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10
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Luchinat E, Barbieri L, Campbell TF, Banci L. Real-Time Quantitative In-Cell NMR: Ligand Binding and Protein Oxidation Monitored in Human Cells Using Multivariate Curve Resolution. Anal Chem 2020; 92:9997-10006. [PMID: 32551584 PMCID: PMC7735651 DOI: 10.1021/acs.analchem.0c01677] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
![]()
In-cell NMR can investigate
protein conformational changes at atomic
resolution, such as those changes induced by drug binding or chemical
modifications, directly in living human cells, and therefore has great
potential in the context of drug development as it can provide an
early assessment of drug potency. NMR bioreactors can greatly improve
the cell sample stability over time and, more importantly, allow for
recording in-cell NMR data in real time to monitor the evolution of
intracellular processes, thus providing unique insights into the kinetics
of drug-target interactions. However, current implementations are
limited by low cell viability at >24 h times, the reduced sensitivity
compared to “static” experiments and the lack of protocols
for automated and quantitative analysis of large amounts of data.
Here, we report an improved bioreactor design which maintains human
cells alive and metabolically active for up to 72 h, and a semiautomated
workflow for quantitative analysis of real-time in-cell NMR data relying
on Multivariate Curve Resolution. We apply this setup to monitor protein–ligand
interactions and protein oxidation in real time. High-quality concentration
profiles can be obtained from noisy 1D and 2D NMR data with high temporal
resolution, allowing further analysis by fitting with kinetic models.
This unique approach can therefore be applied to investigate complex
kinetic behaviors of macromolecules in a cellular setting, and could
be extended in principle to any real-time NMR application in live
cells.
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Affiliation(s)
- Enrico Luchinat
- Magnetic Resonance Center - CERM, University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Florence Italy.,Center for Colloids and Surface Science - CSGI, Via della Lastruccia 3, 50019 Sesto Fiorentino, Florence Italy
| | - Letizia Barbieri
- Magnetic Resonance Center - CERM, University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Florence Italy.,Interuniversity Consortium for Magnetic Resonance of Metalloproteins - CIRMMP, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Florence Italy
| | - Timothy F Campbell
- Magnetic Resonance Center - CERM, University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Florence Italy
| | - Lucia Banci
- Magnetic Resonance Center - CERM, University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Florence Italy.,Department of Chemistry "Ugo Schiff", University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Florence Italy
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11
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In-Cell NMR: Analysis of Protein-Small Molecule Interactions, Metabolic Processes, and Protein Phosphorylation. Int J Mol Sci 2019; 20:ijms20020378. [PMID: 30658393 PMCID: PMC6359726 DOI: 10.3390/ijms20020378] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 01/11/2019] [Accepted: 01/13/2019] [Indexed: 01/31/2023] Open
Abstract
Nuclear magnetic resonance (NMR) spectroscopy enables the non-invasive observation of biochemical processes, in living cells, at comparably high spectral and temporal resolution. Preferably, means of increasing the detection limit of this powerful analytical method need to be applied when observing cellular processes under physiological conditions, due to the low sensitivity inherent to the technique. In this review, a brief introduction to in-cell NMR, protein–small molecule interactions, posttranslational phosphorylation, and hyperpolarization NMR methods, used for the study of metabolites in cellulo, are presented. Recent examples of method development in all three fields are conceptually highlighted, and an outlook into future perspectives of this emerging area of NMR research is given.
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12
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Breindel L, Burz DS, Shekhtman A. Interaction proteomics by using in-cell NMR spectroscopy. J Proteomics 2019; 191:202-211. [PMID: 29427760 PMCID: PMC6082733 DOI: 10.1016/j.jprot.2018.02.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Revised: 01/31/2018] [Accepted: 02/04/2018] [Indexed: 12/17/2022]
Abstract
A synopsis of in-cell NMR spectroscopic approaches to study interaction proteomics in prokaryotic and eukaryotic cells is presented. We describe the use of in-cell NMR spectroscopy to resolve high resolution protein structures, discuss methodologies for determining and analyzing high and low affinity protein-target structural interactions, including intrinsically disordered proteins, and detail important functional interactions that result from these interactions. SIGNIFICANCE: The ultimate goal of structural and biochemical research is to understand how macromolecular interactions give rise to and regulate biological activity in living cells. The challenge is formidable due to the complexity that arises not only from the number of proteins (genes) expressed by the organism, but also from the combinatorial interactions between them. Despite ongoing efforts to decipher the complex nature of protein interactions, new methods for structurally characterizing protein complexes are needed to fully understand molecular networks. With the onset of in-cell NMR spectroscopy, molecular structures and interactions can be studied under physiological conditions shedding light on the structural underpinning of biological activity.
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Affiliation(s)
- Leonard Breindel
- Department of Chemistry, University at Albany, State University of New York, Albany, NY 12222, USA
| | - David S Burz
- Department of Chemistry, University at Albany, State University of New York, Albany, NY 12222, USA
| | - Alexander Shekhtman
- Department of Chemistry, University at Albany, State University of New York, Albany, NY 12222, USA.
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13
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Applications of In-Cell NMR in Structural Biology and Drug Discovery. Int J Mol Sci 2019; 20:ijms20010139. [PMID: 30609728 PMCID: PMC6337603 DOI: 10.3390/ijms20010139] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Revised: 12/24/2018] [Accepted: 12/29/2018] [Indexed: 01/23/2023] Open
Abstract
In-cell nuclear magnetic resonance (NMR) is a method to provide the structural information of a target at an atomic level under physiological conditions and a full view of the conformational changes of a protein caused by ligand binding, post-translational modifications or protein⁻protein interactions in living cells. Previous in-cell NMR studies have focused on proteins that were overexpressed in bacterial cells and isotopically labeled proteins injected into oocytes of Xenopus laevis or delivered into human cells. Applications of in-cell NMR in probing protein modifications, conformational changes and ligand bindings have been carried out in mammalian cells by monitoring isotopically labeled proteins overexpressed in living cells. The available protocols and successful examples encourage wide applications of this technique in different fields such as drug discovery. Despite the challenges in this method, progress has been made in recent years. In this review, applications of in-cell NMR are summarized. The successful applications of this method in mammalian and bacterial cells make it feasible to play important roles in drug discovery, especially in the step of target engagement.
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14
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Costello WN, Xiao Y, Frederick KK. DNP-Assisted NMR Investigation of Proteins at Endogenous Levels in Cellular Milieu. Methods Enzymol 2018; 615:373-406. [PMID: 30638534 DOI: 10.1016/bs.mie.2018.08.023] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Structural investigations of biomolecules are typically confined to in vitro systems under extremely limited conditions. These investigations yield invaluable insights, but such experiments cannot capture important structural features imposed by cellular environments. Structural studies of proteins in their native contexts are not only possible using state-of-the-art sensitivity-enhanced (dynamic nuclear polarization, DNP) solid-state nuclear magnetic resonance (NMR) techniques, but these studies also demonstrate that the cellular context can and does have a dramatic influence on protein structure. In this chapter, we describe methods to prepare samples of isotopically labeled proteins at endogenous levels in cellular contexts alongside quality control methods to ensure that such samples accurately model important features of the cellular environment.
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Affiliation(s)
| | - Yiling Xiao
- UT Southwestern Medical Center, Dallas, TX, United States
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15
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Luchinat E, Banci L. In-Cell NMR in Human Cells: Direct Protein Expression Allows Structural Studies of Protein Folding and Maturation. Acc Chem Res 2018; 51:1550-1557. [PMID: 29869502 DOI: 10.1021/acs.accounts.8b00147] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Cellular structural biology methods are needed to characterize biological processes at atomic resolution in the physiological environment of the cell. Toward this goal, solution in-cell NMR is a powerful approach because it provides structural and dynamic data on macromolecules inside living cells. Several approaches have been developed for in-cell NMR in cultured human cells, which are needed to study processes related to human diseases that rely on the delivery of exogenous macromolecules to the cells. Such strategies, however, may not be applicable to proteins that are sensitive to the external environment or prone to aggregate and can introduce artifacts during protein purification or delivery. As a complementary approach, direct protein expression for in-cell NMR in human cells was developed. This strategy is especially useful when studying processes like protein folding, maturation, and post-translational modification, starting right after protein synthesis. Compared with the protein expression techniques in mammalian cells commonly used in cellular biology, the low sensitivity of NMR requires higher protein levels. Among the cell lines used for high-yield protein expression, the HEK293T cell line was chosen, as it can be efficiently transfected with a cost-effective reagent. A vector originally designed for secreted proteins allows high-level cytosolic protein expression. For isotopic labeling, commercially available or homemade labeled media are employed. Uniform or amino acid type-selective labeling strategies are possible. Protein expression can be targeted to specific organelles (e.g., mitochondria), allowing for in organello NMR applications. A variant of the approach was developed that allows the sequential expression of two or more proteins, with only one selectively labeled. Protein expression in HEK293T cells was applied to recapitulate the maturation steps of intracellular superoxide dismutase 1 (SOD1) and to study the effect of mutations linked to familial amyotrophic lateral sclerosis (fALS) by in-cell NMR. Intracellular wild-type SOD1 spontaneously binds zinc, while it needs the copper chaperone for superoxide dismutase (CCS) for copper delivery and disulfide bond formation. Some fALS-linked mutations impair zinc binding and cause SOD1 to irreversibly unfold, likely forming the precursor of cytotoxic aggregates. The SOD-like domain of CCS acts as a molecular chaperone toward mutant SOD1, stabilizing its folding and allowing zinc binding and correct maturation. Changes in protein redox state distributions can also be investigated by in-cell NMR. Mitochondrial proteins require the redox-regulating partners glutaredoxin 1 (Grx1) and thioredoxin (Trx) to remain in the reduced, import-competent state in the cytosol, whereas SOD1 requires CCS for disulfide bond formation. In both cases, the proteins do not equilibrate with the cytosolic redox pool. Cysteine oxidation in response to oxidative stress can also be monitored. In the near future, in-cell NMR in human cells will likely benefit from technological advancements in NMR hardware, the development of bioreactor systems for increased sample lifetime, the application of paramagnetic NMR to obtain structural restraints, and advanced tools for genome engineering and should be increasingly integrated with advanced cellular imaging techniques.
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Affiliation(s)
- Enrico Luchinat
- Magnetic Resonance Center - CERM, University of Florence, 50019 Sesto Fiorentino, Italy
- Department of Experimental and Clinical Biomedical Sciences “Mario Serio”, University of Florence, 50134 Florence, Italy
| | - Lucia Banci
- Magnetic Resonance Center - CERM, University of Florence, 50019 Sesto Fiorentino, Italy
- Department of Chemistry, University of Florence, 50019 Sesto Fiorentino, Italy
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16
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New structural and functional insights from in-cell NMR. Emerg Top Life Sci 2018; 2:29-38. [PMID: 33525780 DOI: 10.1042/etls20170136] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Revised: 12/13/2017] [Accepted: 12/18/2017] [Indexed: 11/17/2022]
Abstract
In recent years, it has become evident that structural characterization would gain significantly in terms of biological relevance if framed within a cellular context, while still maintaining the atomic resolution. Therefore, major efforts have been devoted to developing Cellular Structural Biology approaches. In this respect, in-cell NMR can provide and has provided relevant contributions to the field, not only to investigate the structural and dynamical properties of macromolecules in solution but, even more relevant, to understand functional processes directly in living cells and the factors that modulate them, such as exogenous molecules, partner proteins, and oxidative stress. In this commentary, we review and discuss some of the main contributions to the understanding of protein structural and functional properties achieved by in-cell NMR.
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17
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Mochizuki A, Saso A, Zhao Q, Kubo S, Nishida N, Shimada I. Balanced Regulation of Redox Status of Intracellular Thioredoxin Revealed by in-Cell NMR. J Am Chem Soc 2018; 140:3784-3790. [PMID: 29509009 DOI: 10.1021/jacs.8b00426] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
To understand how intracellular proteins respond to oxidative stresses, the redox status of the target protein, as well as the intracellular redox potential ( EGSH), which is defined by the concentrations of reduced and oxidized glutathione, should be observed simultaneously within living cells. In this study, we developed a method that can monitor the redox status of thioredoxin (Trx) and EGSH by direct NMR observation of Trx and glutathione within living cells. Unlike the midpoint potential of Trx measured in vitro (∼ -300 mV), the intracellular Trx exhibited the redox transition at EGSH between -250 and -200 mV, the range known to trigger the oxidative stress-mediated signalings. Furthermore, we quantified the contribution of Trx reductase to the redox status of Trx, demonstrating that the redox profile of Trx is determined by the interplay between the elevation of EGSH and the reduction by Trx reductase and other endogenous molecules.
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Affiliation(s)
- Ayano Mochizuki
- Graduate School of Pharmaceutical Sciences , The University of Tokyo , 7-3-1 Hongo , Bunkyo-ku, Tokyo 113-0033 , Japan
| | - Arata Saso
- Graduate School of Pharmaceutical Sciences , The University of Tokyo , 7-3-1 Hongo , Bunkyo-ku, Tokyo 113-0033 , Japan
| | - Qingci Zhao
- Graduate School of Pharmaceutical Sciences , The University of Tokyo , 7-3-1 Hongo , Bunkyo-ku, Tokyo 113-0033 , Japan
| | - Satoshi Kubo
- Graduate School of Pharmaceutical Sciences , The University of Tokyo , 7-3-1 Hongo , Bunkyo-ku, Tokyo 113-0033 , Japan
| | - Noritaka Nishida
- Graduate School of Pharmaceutical Sciences , The University of Tokyo , 7-3-1 Hongo , Bunkyo-ku, Tokyo 113-0033 , Japan
| | - Ichio Shimada
- Graduate School of Pharmaceutical Sciences , The University of Tokyo , 7-3-1 Hongo , Bunkyo-ku, Tokyo 113-0033 , Japan
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18
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Mitri E, Barbieri L, Vaccari L, Luchinat E. 15N isotopic labelling for in-cell protein studies by NMR spectroscopy and single-cell IR synchrotron radiation FTIR microscopy: a correlative study. Analyst 2018; 143:1171-1181. [DOI: 10.1039/c7an01464c] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The effect of 15N-enrichment on human cells analyzed by correlative in-cell NMR and single-cell SR-FTIR experiments.
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Affiliation(s)
- E. Mitri
- Elettra – Sincrotrone Trieste S.C.p.A
- SISSI Beamline – Chemical and Life Sciences Branch
- 34149, Basovizza
- Italy
| | - L. Barbieri
- Magnetic Resonance Centre (CERM)
- University of Florence
- 50019 Sesto Fiorentino
- Italy
- Interuniversity Consortium for Magnetic Resonance of Metallo Proteins (CIRMMP)
| | - L. Vaccari
- Elettra – Sincrotrone Trieste S.C.p.A
- SISSI Beamline – Chemical and Life Sciences Branch
- 34149, Basovizza
- Italy
| | - E. Luchinat
- Department of Experimental and Clinical Biomedical Sciences “Mario Serio”
- University of Florence
- 50134 Florence
- Italy
- Magnetic Resonance Centre (CERM)
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19
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Barbieri L, Luchinat E, Banci L. Intracellular metal binding and redox behavior of human DJ-1. J Biol Inorg Chem 2017; 23:61-69. [DOI: 10.1007/s00775-017-1509-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Accepted: 10/18/2017] [Indexed: 12/21/2022]
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20
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Abstract
Conditionally disordered proteins are either ordered or disordered depending on the environmental context. The substrates of the mitochondrial intermembrane space (IMS) oxidoreductase Mia40 are synthesized on cytosolic ribosomes and diffuse as intrinsically disordered proteins to the IMS, where they fold into their functional conformations; behaving thus as conditionally disordered proteins. It is not clear how the sequences of these polypeptides encode at the same time for their ability to adopt a folded structure and to remain unfolded. Here we characterize the disorder-to-order transition of a Mia40 substrate, the human small copper chaperone Cox17. Using an integrated real-time approach, including chromatography, fluorescence, CD, FTIR, SAXS, NMR, and MS analysis, we demonstrate that in this mitochondrial protein, the conformational switch between disordered and folded states is controlled by the formation of a single disulfide bond, both in the presence and in the absence of Mia40. We provide molecular details on how the folding of a conditionally disordered protein is tightly regulated in time and space, in such a way that the same sequence is competent for protein translocation and activity.
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21
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Fraga H, Pujols J, Gil-Garcia M, Roque A, Bernardo-Seisdedos G, Santambrogio C, Bech-Serra JJ, Canals F, Bernadó P, Grandori R, Millet O, Ventura S. Disulfide driven folding for a conditionally disordered protein. Sci Rep 2017; 7:16994. [PMID: 29208936 PMCID: PMC5717278 DOI: 10.1038/s41598-017-17259-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Accepted: 11/23/2017] [Indexed: 11/09/2022] Open
Abstract
Conditionally disordered proteins are either ordered or disordered depending on the environmental context. The substrates of the mitochondrial intermembrane space (IMS) oxidoreductase Mia40 are synthesized on cytosolic ribosomes and diffuse as intrinsically disordered proteins to the IMS, where they fold into their functional conformations; behaving thus as conditionally disordered proteins. It is not clear how the sequences of these polypeptides encode at the same time for their ability to adopt a folded structure and to remain unfolded. Here we characterize the disorder-to-order transition of a Mia40 substrate, the human small copper chaperone Cox17. Using an integrated real-time approach, including chromatography, fluorescence, CD, FTIR, SAXS, NMR, and MS analysis, we demonstrate that in this mitochondrial protein, the conformational switch between disordered and folded states is controlled by the formation of a single disulfide bond, both in the presence and in the absence of Mia40. We provide molecular details on how the folding of a conditionally disordered protein is tightly regulated in time and space, in such a way that the same sequence is competent for protein translocation and activity.
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Affiliation(s)
- Hugo Fraga
- Institut de Biotecnologia i Biomedicina. Universitat Autònoma de Barcelona, 08193, Bellaterra, Spain.,Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, 08193, Bellaterra, Spain.,Departamento de Bioquimica, Faculdade de Medicina da Universidade do Porto, Porto, Portugal
| | - Jordi Pujols
- Institut de Biotecnologia i Biomedicina. Universitat Autònoma de Barcelona, 08193, Bellaterra, Spain.,Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, 08193, Bellaterra, Spain
| | - Marcos Gil-Garcia
- Institut de Biotecnologia i Biomedicina. Universitat Autònoma de Barcelona, 08193, Bellaterra, Spain.,Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, 08193, Bellaterra, Spain
| | - Alicia Roque
- Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, 08193, Bellaterra, Spain
| | | | - Carlo Santambrogio
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Milano, Italy
| | | | - Francesc Canals
- Vall d'Hebron Institute of Oncology (VHIO), Barcelona, Spain
| | - Pau Bernadó
- Centre de Biochimie Structurale, INSERM-U1054, CNRS UMR-5048, Université de Montpellier, 29, rue de Navacelles, 34090, Montpellier, France
| | - Rita Grandori
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Milano, Italy
| | - Oscar Millet
- Protein Stability and Inherited Diseases Laboratory, CIC bioGUNE, 48160, Derio, Spain
| | - Salvador Ventura
- Institut de Biotecnologia i Biomedicina. Universitat Autònoma de Barcelona, 08193, Bellaterra, Spain. .,Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, 08193, Bellaterra, Spain.
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22
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Kyne C, Crowley PB. Short Arginine Motifs Drive Protein Stickiness in the Escherichia coli Cytoplasm. Biochemistry 2017; 56:5026-5032. [DOI: 10.1021/acs.biochem.7b00731] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Ciara Kyne
- School of Chemistry, National University of Ireland Galway, University Road, Galway, H91 TK33, Ireland
| | - Peter B. Crowley
- School of Chemistry, National University of Ireland Galway, University Road, Galway, H91 TK33, Ireland
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23
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The Role of Metal Binding in the Amyotrophic Lateral Sclerosis-Related Aggregation of Copper-Zinc Superoxide Dismutase. Molecules 2017; 22:molecules22091429. [PMID: 28850080 PMCID: PMC6151412 DOI: 10.3390/molecules22091429] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Revised: 08/22/2017] [Accepted: 08/27/2017] [Indexed: 12/13/2022] Open
Abstract
Protein misfolding and conformational changes are common hallmarks in many neurodegenerative diseases involving formation and deposition of toxic protein aggregates. Although many players are involved in the in vivo protein aggregation, physiological factors such as labile metal ions within the cellular environment are likely to play a key role. In this review, we elucidate the role of metal binding in the aggregation process of copper-zinc superoxide dismutase (SOD1) associated to amyotrophic lateral sclerosis (ALS). SOD1 is an extremely stable Cu-Zn metalloprotein in which metal binding is crucial for folding, enzymatic activity and maintenance of the native conformation. Indeed, demetalation in SOD1 is known to induce misfolding and aggregation in physiological conditions in vitro suggesting that metal binding could play a key role in the pathological aggregation of SOD1. In addition, this study includes recent advances on the role of aberrant metal coordination in promoting SOD1 aggregation, highlighting the influence of metal ion homeostasis in pathologic aggregation processes.
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24
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Sun J, Wei X, Lu Y, Cui M, Li F, Lu J, Liu Y, Zhang X. Glutaredoxin 1 (GRX1) inhibits oxidative stress and apoptosis of chondrocytes by regulating CREB/HO-1 in osteoarthritis. Mol Immunol 2017; 90:211-218. [PMID: 28843170 DOI: 10.1016/j.molimm.2017.08.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2017] [Revised: 07/31/2017] [Accepted: 08/14/2017] [Indexed: 01/11/2023]
Abstract
GRX1 (glutaredoxin1), a sulfhydryl disulfide oxidoreductase, is involved in many cellular processes, including anti-oxidation, anti-apoptosis, and regulation of cell differentiation. However, the role of GRX1 in the oxidative stress and apoptosis of osteoarthritis chondrocytes remains unclear, prompting the current study. Protein and mRNA expressions were measured by Western blot and RT-qPCR. Oxidative stress was detected by the measurement of MDA and SOD contents. Cells apoptosis were detected by Annexin V-FITC/PI and caspase-3 activity assays. We found that the mRNA and protein expressions of GRX1 were significantly down-regulated in osteoarthritis tissues and cells. GRX1 overexpression increased the mRNA and protein expression of CREB and HO-1. Meanwhile, GRX1 overexpression inhibited oxidative stress and apoptosis in osteoarthritis chondrocytes. Furthermore, we found that GRX1 overexpression regulated HO-1 by increasing CREB, and that HO-1 regulated oxidative stress and apoptosis in osteoarthritis chondrocytes. Thus, GRX1 overexpression constrains oxidative stress and apoptosis in osteoarthritis chondrocytes by regulating CREB/HO-1, providing a novel insight into the molecular mechanism and potential treatment of osteoarthritis.
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Affiliation(s)
- Jie Sun
- Department of Orthopaedic Trauma, Tianjin Hospital, Tianjin, 300211, China
| | - Xuelei Wei
- Department of Orthopaedic Trauma, Tianjin Hospital, Tianjin, 300211, China.
| | - Yandong Lu
- Department of Orthopaedic Trauma, Tianjin Hospital, Tianjin, 300211, China
| | - Meng Cui
- Department of Orthopaedic Trauma, Tianjin Hospital, Tianjin, 300211, China
| | - Fangguo Li
- Department of Orthopaedic Trauma, Tianjin Hospital, Tianjin, 300211, China
| | - Jie Lu
- Department of Orthopaedic Trauma, Tianjin Hospital, Tianjin, 300211, China
| | - Yunjiao Liu
- Department of Orthopaedic Trauma, Tianjin Hospital, Tianjin, 300211, China
| | - Xi Zhang
- Department of Orthopaedic Trauma, Tianjin Hospital, Tianjin, 300211, China
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25
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Luchinat E, Banci L. In-cell NMR: a topical review. IUCRJ 2017; 4:108-118. [PMID: 28250949 PMCID: PMC5330521 DOI: 10.1107/s2052252516020625] [Citation(s) in RCA: 89] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Accepted: 12/29/2016] [Indexed: 05/18/2023]
Abstract
Classical structural biology approaches allow structural characterization of biological macromolecules in vitro, far from their physiological context. Nowadays, thanks to the wealth of structural data available and to technological and methodological advances, the interest of the research community is gradually shifting from pure structural determination towards the study of functional aspects of biomolecules. Therefore, a cellular structural approach is ideally needed to characterize biological molecules, such as proteins, in their native cellular environment and the functional processes that they are involved in. In-cell NMR is a new application of high-resolution nuclear magnetic resonance spectroscopy that allows structural and dynamical features of proteins and other macromolecules to be analyzed directly in living cells. Owing to its challenging nature, this methodology has shown slow, but steady, development over the past 15 years. To date, several in-cell NMR approaches have been successfully applied to both bacterial and eukaryotic cells, including several human cell lines, and important structural and functional aspects have been elucidated. In this topical review, the major advances of in-cell NMR are summarized, with a special focus on recent developments in eukaryotic and mammalian cells.
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Affiliation(s)
- Enrico Luchinat
- Magnetic Resonance Center – CERM, University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Florence, Italy
- Department of Biomedical, Clinical and Experimental Sciences, University of Florence, Viale Morgagni 50, 50134 Florence, Italy
| | - Lucia Banci
- Magnetic Resonance Center – CERM, University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Florence, Italy
- Department of Chemistry, University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino, Florence, Italy
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26
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Towards understanding cellular structure biology: In-cell NMR. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2017; 1865:547-557. [PMID: 28257994 DOI: 10.1016/j.bbapap.2017.02.018] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Revised: 02/22/2017] [Accepted: 02/27/2017] [Indexed: 12/20/2022]
Abstract
To watch biological macromolecules perform their functions inside the living cells is the dream of any biologists. In-cell nuclear magnetic resonance is a branch of biomolecular NMR spectroscopy that can be used to observe the structures, interactions and dynamics of these molecules in the living cells at atomic level. In principle, in-cell NMR can be applied to different cellular systems to achieve biologically relevant structural and functional information. In this review, we summarize the existing approaches in this field and discuss its applications in protein interactions, folding, stability and post-translational modifications. We hope this review will emphasize the effectiveness of in-cell NMR for studies of intricate biological processes and for structural analysis in cellular environments.
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27
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Pastore A, Temussi PA. The Emperor's new clothes: Myths and truths of in-cell NMR. Arch Biochem Biophys 2017; 628:114-122. [PMID: 28259514 DOI: 10.1016/j.abb.2017.02.008] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2017] [Revised: 02/24/2017] [Accepted: 02/27/2017] [Indexed: 11/25/2022]
Abstract
In-cell NMR is a technique developed to study the structure and dynamical behavior of biological macromolecules in their natural environment, circumventing all isolation and purification steps. In principle, the potentialities of the technique are enormous, not only for the possibility of bypassing all purification steps but, even more importantly, for the wealth of information that can be gained from directly monitoring interactions among biological macromolecules in a natural cell. Here, we review critically the promises, successes and limits of this technique as it stands now. Interestingly, many of the problems of NMR in bacterial cells stem from the artificially high concentration of the protein under study whose overexpression is anyway necessary to select it from the background. This has, as a consequence, that when overexpressed, most globular proteins, do not show an NMR spectrum, limiting the applicability of the technique to intrinsically unfolded or specifically behaving proteins. The outlook for in-cell NMR of eukaryotic cells is more promising and is possibly the most attracting aspect for the future.
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Affiliation(s)
- Annalisa Pastore
- The Wohl Institute, King's College London, 5 Cutcombe Rd, London SE5 9RT, UK; University of Pavia, Department of Molecular Medicine, Pavia, Italy.
| | - Piero Andrea Temussi
- The Wohl Institute, King's College London, 5 Cutcombe Rd, London SE5 9RT, UK; University of Naples "Federico II", Department of Chemical Sciences, Naples, Italy
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28
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Mitochondrial disulfide relay and its substrates: mechanisms in health and disease. Cell Tissue Res 2016; 367:59-72. [DOI: 10.1007/s00441-016-2481-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 07/18/2016] [Indexed: 01/06/2023]
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29
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Abstract
In-cell NMR spectroscopy is a unique tool for characterizing biological macromolecules in their physiological environment at atomic resolution. Recent progress in NMR instruments and sample preparation methods allows functional processes, such as metal uptake, disulfide-bond formation and protein folding, to be analyzed by NMR in living, cultured human cells. This protocol describes the necessary steps to overexpress one or more proteins of interest inside human embryonic kidney 293T (HEK293T) cells, and it explains how to set up in-cell NMR experiments. The cDNA is transiently transfected as a complex with a cationic polymer (DNA:PEI (polyethylenimine)), and protein expression is carried on for 2-3 d, after which the NMR sample is prepared. (1)H and (1)H-(15)N correlation NMR experiments (for example, using band-selective optimized flip-angle short-transient heteronuclear multiple quantum coherence (SOFAST-HMQC)) can be carried out in <2 h, ensuring cell viability. Uniform (15)N labeling and amino-acid-specific (e.g., cysteine, methionine) labeling schemes are possible. The entire procedure takes 4 d from cell culture seeding to NMR data collection.
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30
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Fuccio C, Luchinat E, Barbieri L, Neri S, Fragai M. Algal autolysate medium to label proteins for NMR in mammalian cells. JOURNAL OF BIOMOLECULAR NMR 2016; 64:275-280. [PMID: 27106902 DOI: 10.1007/s10858-016-0026-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Accepted: 02/22/2016] [Indexed: 06/05/2023]
Abstract
In-cell NMR provides structural and functional information on proteins directly inside living cells. At present, the high costs of the labeled media for mammalian cells represent a limiting factor for the development of this methodology. Here we report a protocol to prepare a homemade growth medium from Spirulina platensis autolysate, suitable to express uniformly labeled proteins inside mammalian cells at a reduced cost-per-sample. The human proteins SOD1 and Mia40 were overexpressed in human cells grown in (15)N-enriched S. platensis algal-derived medium, and high quality in-cell NMR spectra were obtained.
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Affiliation(s)
- Carmelo Fuccio
- Magnetic Resonance Center (CERM), University of Florence, Via L. Sacconi 6, 50019, Sesto Fiorentino, Florence, Italy
| | - Enrico Luchinat
- Magnetic Resonance Center (CERM), University of Florence, Via L. Sacconi 6, 50019, Sesto Fiorentino, Florence, Italy
- Department of Biomedical, Clinical and Experimental Sciences, University of Florence, Viale Morgagni 50, 50134, Florence, Italy
| | - Letizia Barbieri
- Magnetic Resonance Center (CERM), University of Florence, Via L. Sacconi 6, 50019, Sesto Fiorentino, Florence, Italy
- Giotto Biotech S.R.L., Via Madonna del Piano 6, 50019, Sesto Fiorentino, Florence, Italy
| | - Sara Neri
- Giotto Biotech S.R.L., Via Madonna del Piano 6, 50019, Sesto Fiorentino, Florence, Italy
| | - Marco Fragai
- Magnetic Resonance Center (CERM), University of Florence, Via L. Sacconi 6, 50019, Sesto Fiorentino, Florence, Italy.
- Department of Chemistry "Ugo Schiff", University of Florence, Via della Lastruccia 3, 50019, Sesto Fiorentino, Florence, Italy.
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31
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Sequential protein expression and selective labeling for in-cell NMR in human cells. Biochim Biophys Acta Gen Subj 2016; 1860:527-33. [DOI: 10.1016/j.bbagen.2015.12.023] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Revised: 12/17/2015] [Accepted: 12/22/2015] [Indexed: 11/23/2022]
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Abstract
Conventional structural and chemical biology approaches are applied to macromolecules extrapolated from their native context. When this is done, important structural and functional features of macromolecules, which depend on their native network of interactions within the cell, may be lost. In-cell nuclear magnetic resonance is a branch of biomolecular NMR spectroscopy that allows macromolecules to be analyzed in living cells, at the atomic level. In-cell NMR can be applied to several cellular systems to obtain biologically relevant structural and functional information. Here we summarize the existing approaches and focus on the applications to protein folding, interactions, and post-translational modifications.
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Affiliation(s)
- Enrico Luchinat
- From the Magnetic Resonance Center (CERM), the Department of Biomedical, Clinical and Experimental Sciences, and
| | - Lucia Banci
- From the Magnetic Resonance Center (CERM), the Department of Chemistry, University of Florence, Florence 50121, Italy
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33
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Direct structural evidence of protein redox regulation obtained by in-cell NMR. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1863:198-204. [PMID: 26589182 DOI: 10.1016/j.bbamcr.2015.11.009] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Revised: 11/04/2015] [Accepted: 11/07/2015] [Indexed: 12/30/2022]
Abstract
The redox properties of cellular environments are critical to many functional processes, and are strictly controlled in all living organisms. The glutathione-glutathione disulfide (GSH-GSSG) couple is the most abundant intracellular redox couple. A GSH redox potential can be calculated for each cellular compartment, which reflects the redox properties of that environment. This redox potential is often used to predict the redox state of a disulfide-containing protein, based on thermodynamic considerations. However, thiol-disulfide exchange reactions are often catalyzed by specific partners, and the distribution of the redox states of a protein may not correspond to the thermodynamic equilibrium with the GSH pool. Ideally, the protein redox state should be measured directly, bypassing the need to extrapolate from the GSH. Here, by in-cell NMR, we directly observe the redox state of three human proteins, Cox17, Mia40 and SOD1, in the cytoplasm of human and bacterial cells. We compare the observed distributions of redox states with those predicted by the GSH redox potential, and our results partially agree with the predictions. Discrepancies likely arise from the fact that the redox state of SOD1 is controlled by a specific partner, its copper chaperone (CCS), in a pathway which is not linked to the GSH redox potential. In principle, in-cell NMR allows determining whether redox proteins are at the equilibrium with GSH, or they are kinetically regulated. Such approach does not need assumptions on the redox potential of the environment, and provides a way to characterize each redox-regulating pathway separately.
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Leal SS, Cristóvão JS, Biesemeier A, Cardoso I, Gomes CM. Aberrant zinc binding to immature conformers of metal-free copper-zinc superoxide dismutase triggers amorphous aggregation. Metallomics 2015; 7:333-46. [PMID: 25554447 DOI: 10.1039/c4mt00278d] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Superoxide dismutase 1 (SOD1) is a Cu/Zn metalloenzyme that aggregates in amyotrophic lateral sclerosis (ALS), a fatal neurodegenerative disorder. Correct metal insertion during SOD1 biosynthesis is critical to prevent misfolding; however Zn(2+) can bind to the copper-site leading to an aberrantly metallated protein. These effects of Zn(2+) misligation on SOD1 aggregation remain to be explored, even though Zn(2+) levels are upregulated in ALS motor neurons. Here we use complementary biophysical methods to investigate Zn(2+) binding and its effects on the aggregation of three immature metal-free SOD1 conformers that represent biogenesis intermediates: dimeric, monomeric and reduced monomeric SOD1. Using isothermal titration calorimetry we determined that Zn(2+) binds to all conformers both at the zinc- as well as to the copper-site; however Zn(2+) binding mechanisms to the zinc-site have distinct characteristics across immature conformers. We show that this 'zinc overload' of immature SOD1 promotes intermolecular interactions, as evidenced by dynamic light scattering and ThT fluorescence kinetic studies. Analysis of aged zinc-induced aggregates by energy-dispersive X-ray and electron energy-loss spectroscopy shows that aggregates integrate some Zn(2+). In addition, electron diffraction analysis identifies nano-scaled crystalline materials and amyloid fibril-like reflections. Transmission electron microscopy reveals that Zn(2+) diverts the SOD1 aggregation pathway from fibrils to amorphous aggregate, and electrophoretic analysis evidences an increase in insoluble materials. Overall, we provide evidence that aberrant zinc coordination to immature conformers broadens the population of SOD1 misfolded species at early aggregation stages and provide evidence for a high structural polymorphism and heterogeneity of SOD1 aggregates.
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Affiliation(s)
- Sónia S Leal
- Instituto Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal.
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35
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Barbieri L, Luchinat E, Banci L. Protein interaction patterns in different cellular environments are revealed by in-cell NMR. Sci Rep 2015; 5:14456. [PMID: 26399546 PMCID: PMC4585868 DOI: 10.1038/srep14456] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Accepted: 08/20/2015] [Indexed: 12/27/2022] Open
Abstract
In-cell NMR allows obtaining atomic-level information on biological macromolecules in their physiological environment. Soluble proteins may interact with the cellular environment in different ways: either specifically, with their functional partners, or non-specifically, with other cellular components. Such behaviour often causes the disappearance of the NMR signals. Here we show that by introducing mutations on the human protein profilin 1, used here as a test case, the in-cell NMR signals can be recovered. In human cells both specific and non-specific interactions are present, while in bacterial cells only the effect of non-specific interactions is observed. By comparing the NMR signal recovery pattern in human and bacterial cells, the relative contribution of each type of interaction can be assessed. This strategy allows detecting solution in-cell NMR spectra of soluble proteins without altering their fold, thus extending the applicability of in-cell NMR to a wider range of proteins.
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Affiliation(s)
- Letizia Barbieri
- Magnetic Resonance Center - CERM, University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Florence, Italy.,Giotto Biotech S.r.l., Via Madonna del Piano 6, 50019 Sesto Fiorentino, Florence, Italy
| | - Enrico Luchinat
- Magnetic Resonance Center - CERM, University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Florence, Italy.,Department of Biomedical, Clinical and Experimental Sciences, University of Florence, Viale Morgagni 50, 50134 Florence, Italy
| | - Lucia Banci
- Magnetic Resonance Center - CERM, University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Florence, Italy.,Department of Chemistry, University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino, Florence, Italy
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36
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Abstract
The content of mitochondrial proteome is maintained through two highly dynamic processes, the influx of newly synthesized proteins from the cytosol and the protein degradation. Mitochondrial proteins are targeted to the intermembrane space by the mitochondrial intermembrane space assembly pathway that couples their import and oxidative folding. The folding trap was proposed to be a driving mechanism for the mitochondrial accumulation of these proteins. Whether the reverse movement of unfolded proteins to the cytosol occurs across the intact outer membrane is unknown. We found that reduced, conformationally destabilized proteins are released from mitochondria in a size-limited manner. We identified the general import pore protein Tom40 as an escape gate. We propose that the mitochondrial proteome is not only regulated by the import and degradation of proteins but also by their retro-translocation to the external cytosolic location. Thus, protein release is a mechanism that contributes to the mitochondrial proteome surveillance.
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37
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Kaplan M, Cukkemane A, van Zundert GCP, Narasimhan S, Daniëls M, Mance D, Waksman G, Bonvin AMJJ, Fronzes R, Folkers GE, Baldus M. Probing a cell-embedded megadalton protein complex by DNP-supported solid-state NMR. Nat Methods 2015; 12:649-52. [PMID: 25984698 DOI: 10.1038/nmeth.3406] [Citation(s) in RCA: 112] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2014] [Accepted: 03/25/2015] [Indexed: 12/24/2022]
Abstract
Studying biomolecules at atomic resolution in their native environment is the ultimate aim of structural biology. We investigated the bacterial type IV secretion system core complex (T4SScc) by cellular dynamic nuclear polarization-based solid-state nuclear magnetic resonance spectroscopy to validate a structural model previously generated by combining in vitro and in silico data. Our results indicate that T4SScc is well folded in the cellular setting, revealing protein regions that had been elusive when studied in vitro.
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Affiliation(s)
- Mohammed Kaplan
- NMR Spectroscopy, Utrecht University, Utrecht, the Netherlands
| | | | | | | | - Mark Daniëls
- NMR Spectroscopy, Utrecht University, Utrecht, the Netherlands
| | - Deni Mance
- NMR Spectroscopy, Utrecht University, Utrecht, the Netherlands
| | - Gabriel Waksman
- Institute of Structural and Molecular Biology, University College London and Birkbeck, London, UK
| | | | - Rémi Fronzes
- Groupe à 5 ans, Biologie structurale de la secretion bacterienne, Unité mixte de recherche Centre National de la Recherche Scientifique-Institut Pasteur 3528, Institut Pasteur, Paris, France
| | - Gert E Folkers
- NMR Spectroscopy, Utrecht University, Utrecht, the Netherlands
| | - Marc Baldus
- NMR Spectroscopy, Utrecht University, Utrecht, the Netherlands
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38
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Tochio H, Murayama S, Inomata K, Morimoto D, Ohno A, Shirakawa M. [Non-invasive analysis of proteins in living cells using NMR spectroscopy]. YAKUGAKU ZASSHI 2015; 135:391-8. [PMID: 25759048 DOI: 10.1248/yakushi.14-00240-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
NMR spectroscopy enables structural analyses of proteins and has been widely used in the structural biology field in recent decades. NMR spectroscopy can be applied to proteins inside living cells, allowing characterization of their structures and dynamics in intracellular environments. The simplest "in-cell NMR" approach employs bacterial cells; in this approach, live Escherichia coli cells overexpressing a specific protein are subjected to NMR. The cells are grown in an NMR active isotope-enriched medium to ensure that the overexpressed proteins are labeled with the stable isotopes. Thus the obtained NMR spectra, which are derived from labeled proteins, contain atomic-level information about the structure and dynamics of the proteins. Recent progress enables us to work with higher eukaryotic cells such as HeLa and HEK293 cells, for which a number of techniques have been developed to achieve isotope labeling of the specific target protein. In this review, we describe successful use of electroporation for in-cell NMR. In addition, (19)F-NMR to characterize protein-ligand interactions in cells is presented. Because (19)F nuclei rarely exist in natural cells, when (19)F-labeled proteins are delivered into cells and (19)F-NMR signals are observed, one can safely ascertain that these signals originate from the delivered proteins and not other molecules.
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Affiliation(s)
- Hidehito Tochio
- Department of Molecular Engineering, Graduate School of Engineering, Kyoto University
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39
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Nakao LS, Everley RA, Marino SM, Lo SM, de Souza LE, Gygi SP, Gladyshev VN. Mechanism-based proteomic screening identifies targets of thioredoxin-like proteins. J Biol Chem 2015; 290:5685-95. [PMID: 25561728 DOI: 10.1074/jbc.m114.597245] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Thioredoxin (Trx)-fold proteins are protagonists of numerous cellular pathways that are subject to thiol-based redox control. The best characterized regulator of thiols in proteins is Trx1 itself, which together with thioredoxin reductase 1 (TR1) and peroxiredoxins (Prxs) comprises a key redox regulatory system in mammalian cells. However, there are numerous other Trx-like proteins, whose functions and redox interactors are unknown. It is also unclear if the principles of Trx1-based redox control apply to these proteins. Here, we employed a proteomic strategy to four Trx-like proteins containing CXXC motifs, namely Trx1, Rdx12, Trx-like protein 1 (Txnl1) and nucleoredoxin 1 (Nrx1), whose cellular targets were trapped in vivo using mutant Trx-like proteins, under conditions of low endogenous expression of these proteins. Prxs were detected as key redox targets of Trx1, but this approach also supported the detection of TR1, which is the Trx1 reductant, as well as mitochondrial intermembrane proteins AIF and Mia40. In addition, glutathione peroxidase 4 was found to be a Rdx12 redox target. In contrast, no redox targets of Txnl1 and Nrx1 could be detected, suggesting that their CXXC motifs do not engage in mixed disulfides with cellular proteins. For some Trx-like proteins, the method allowed distinguishing redox and non-redox interactions. Parallel, comparative analyses of multiple thiol oxidoreductases revealed differences in the functions of their CXXC motifs, providing important insights into thiol-based redox control of cellular processes.
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Affiliation(s)
- Lia S Nakao
- From the Division of Genetics, Department of Medicine, Brigham & Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115, the Universidade Federal do Paraná, Departamento de Patologia Básica, 81531-980, Curitiba, PR, Brazil, and
| | - Robert A Everley
- the Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115
| | - Stefano M Marino
- From the Division of Genetics, Department of Medicine, Brigham & Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115
| | - Sze M Lo
- the Universidade Federal do Paraná, Departamento de Patologia Básica, 81531-980, Curitiba, PR, Brazil, and
| | - Luiz E de Souza
- the Universidade Federal do Paraná, Departamento de Patologia Básica, 81531-980, Curitiba, PR, Brazil, and
| | - Steven P Gygi
- the Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115
| | - Vadim N Gladyshev
- From the Division of Genetics, Department of Medicine, Brigham & Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115,
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40
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Luchinat E, Gianoncelli A, Mello T, Galli A, Banci L. Combining in-cell NMR and X-ray fluorescence microscopy to reveal the intracellular maturation states of human superoxide dismutase 1. Chem Commun (Camb) 2015; 51:584-7. [DOI: 10.1039/c4cc08129c] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Combined in-cell NMR spectroscopy, X-ray fluorescence and optical fluorescence microscopies allow describing the intracellular maturation states of human SOD1.
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Affiliation(s)
- E. Luchinat
- Magnetic Resonance Center - CERM
- University of Florence
- Sesto Fiorentino
- Italy
- Department of Biomedical
| | - A. Gianoncelli
- Elettra-Sincrotrone Trieste
- Area Science Park
- Basovizza
- Italy
| | - T. Mello
- Department of Biomedical
- Clinical and Experimental Sciences
- University of Florence
- Florence
- Italy
| | - A. Galli
- Department of Biomedical
- Clinical and Experimental Sciences
- University of Florence
- Florence
- Italy
| | - L. Banci
- Magnetic Resonance Center - CERM
- University of Florence
- Sesto Fiorentino
- Italy
- Department of Chemistry
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41
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Smith AE, Zhang Z, Pielak GJ, Li C. NMR studies of protein folding and binding in cells and cell-like environments. Curr Opin Struct Biol 2014; 30:7-16. [PMID: 25479354 DOI: 10.1016/j.sbi.2014.10.004] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2014] [Revised: 10/20/2014] [Accepted: 10/24/2014] [Indexed: 11/18/2022]
Abstract
Proteins function in cells where the concentration of macromolecules can exceed 300g/L. The ways in which this crowded environment affects the physical properties of proteins remain poorly understood. We summarize recent NMR-based studies of protein folding and binding conducted in cells and in vitro under crowded conditions. Many of the observations can be understood in terms of interactions between proteins and the rest of the intracellular environment (i.e. quinary interactions). Nevertheless, NMR studies of folding and binding in cells and cell-like environments remain in their infancy. The frontier involves investigations of larger proteins and further efforts in higher eukaryotic cells.
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Affiliation(s)
- Austin E Smith
- Department of Chemistry, University of North Carolina-Chapel Hill, Chapel Hill, NC 27599-3290, USA
| | - Zeting Zhang
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, PR China
| | - Gary J Pielak
- Department of Chemistry, University of North Carolina-Chapel Hill, Chapel Hill, NC 27599-3290, USA; Department of Biochemistry and Biophysics, University of North Carolina-Chapel Hill, Chapel Hill, NC 27599-3290, USA.
| | - Conggang Li
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, PR China.
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42
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In-cell NMR reveals potential precursor of toxic species from SOD1 fALS mutants. Nat Commun 2014; 5:5502. [PMID: 25429517 DOI: 10.1038/ncomms6502] [Citation(s) in RCA: 90] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Accepted: 10/07/2014] [Indexed: 12/20/2022] Open
Abstract
Mutations in the superoxide dismutase 1 (SOD1) gene are related to familial cases of amyotrophic lateral sclerosis (fALS). Here we exploit in-cell NMR to characterize the protein folding and maturation of a series of fALS-linked SOD1 mutants in human cells and to obtain insight into their behaviour in the cellular context, at the molecular level. The effect of various mutations on SOD1 maturation are investigated by changing the availability of metal ions in the cells, and by coexpressing the copper chaperone for SOD1, hCCS. We observe for most of the mutants the occurrence of an unstructured SOD1 species, unable to bind zinc. This species may be a common precursor of potentially toxic oligomeric species, that are associated with fALS. Coexpression of hCCS in the presence of copper restores the correct maturation of the SOD1 mutants and prevents the formation of the unstructured species, confirming that hCCS also acts as a molecular chaperone.
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43
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Kojer K, Peleh V, Calabrese G, Herrmann JM, Riemer J. Kinetic control by limiting glutaredoxin amounts enables thiol oxidation in the reducing mitochondrial intermembrane space. Mol Biol Cell 2014; 26:195-204. [PMID: 25392302 PMCID: PMC4294668 DOI: 10.1091/mbc.e14-10-1422] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Proteins of the mitochondrial intermembrane space are oxidatively folded by the incorporation of structural disulfide bonds. Efficient protein oxidation in this highly reducing compartment is possible only because glutaredoxins, which could translate the glutathione redox potential into that of protein thiols, are present at limiting levels. The mitochondrial intermembrane space (IMS) harbors an oxidizing machinery that drives import and folding of small cysteine-containing proteins without targeting signals. The main component of this pathway is the oxidoreductase Mia40, which introduces disulfides into its substrates. We recently showed that the IMS glutathione pool is maintained as reducing as that of the cytosol. It thus remained unclear how equilibration of protein disulfides with the IMS glutathione pool is prevented in order to allow oxidation-driven protein import. Here we demonstrate the presence of glutaredoxins in the IMS and show that limiting amounts of these glutaredoxins provide a kinetic barrier to prevent the thermodynamically feasible reduction of Mia40 substrates by the IMS glutathione pool. Moreover, they allow Mia40 to exist in a predominantly oxidized state. Consequently, overexpression of glutaredoxin 2 in the IMS results in a more reduced Mia40 redox state and a delay in oxidative folding and mitochondrial import of different Mia40 substrates. Our findings thus indicate that carefully balanced glutaredoxin amounts in the IMS ensure efficient oxidative folding in the reducing environment of this compartment.
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Affiliation(s)
- Kerstin Kojer
- Cellular Biochemistry, University of Kaiserslautern, 67663 Kaiserslautern, Germany
| | - Valentina Peleh
- Cell Biology, University of Kaiserslautern, 67663 Kaiserslautern, Germany
| | - Gaetano Calabrese
- Cellular Biochemistry, University of Kaiserslautern, 67663 Kaiserslautern, Germany
| | | | - Jan Riemer
- Cellular Biochemistry, University of Kaiserslautern, 67663 Kaiserslautern, Germany
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44
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Barbieri L, Luchinat E, Banci L. Structural insights of proteins in sub-cellular compartments: In-mitochondria NMR. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2014; 1843:2492-6. [DOI: 10.1016/j.bbamcr.2014.06.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Revised: 06/12/2014] [Accepted: 06/16/2014] [Indexed: 10/25/2022]
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45
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Abstract
Ever since scientists realized that cells are the basic building blocks of all life, they have been developing tools to look inside them to reveal the architectures and mechanisms that define their biological functions. Whereas "looking into cells" is typically said in reference to optical microscopy, high-resolution in-cell and on-cell nuclear magnetic resonance (NMR) spectroscopy is a powerful method that offers exciting new possibilities for structural and functional studies in and on live cells. In contrast to conventional imaging techniques, in- and on-cell NMR methods do not provide spatial information on cellular biomolecules. Instead, they enable atomic-resolution insights into the native cell states of proteins, nucleic acids, glycans, and lipids. Here we review recent advances and developments in both fields and discuss emerging concepts that have been delineated with these methods.
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Affiliation(s)
- Darón I Freedberg
- Laboratory of Bacterial Polysaccharides, Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Rockville, Maryland 20852-1448;
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46
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Felli IC, Gonnelli L, Pierattelli R. In-cell ¹³C NMR spectroscopy for the study of intrinsically disordered proteins. Nat Protoc 2014; 9:2005-16. [PMID: 25079425 DOI: 10.1038/nprot.2014.124] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
A large number of proteins carry out their function in highly flexible and disordered states, lacking a well-defined 3D structure. These proteins, referred to as intrinsically disordered proteins (IDPs), are now in the spotlight of modern structural biology. Nuclear magnetic resonance (NMR) spectroscopy represents a unique tool for accessing atomic resolution information on IDPs in complex environments as whole cells, provided that the methods are optimized to their peculiar properties and to the characteristics of in-cell experiments. We describe procedures for the preparation of in-cell NMR samples, as well as for the setup of NMR experiments and their application to in-cell studies, using human α-synuclein overexpressed in Escherichia coli as an example. The expressed protein is labeled with (13)C and (15)N stable isotopes to enable the direct recording of (13)C-detected NMR experiments optimized for the properties of IDPs. The entire procedure covers 24 h, including cell transformation, cell growth overnight, setup of the spectrometer and NMR experiment recording.
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Affiliation(s)
- Isabella C Felli
- Magnetic Resonance Center (CERM), Department of Chemistry 'Ugo Schiff', University of Florence, Sesto Fiorentino, Italy
| | - Leonardo Gonnelli
- Magnetic Resonance Center (CERM), Department of Chemistry 'Ugo Schiff', University of Florence, Sesto Fiorentino, Italy
| | - Roberta Pierattelli
- Magnetic Resonance Center (CERM), Department of Chemistry 'Ugo Schiff', University of Florence, Sesto Fiorentino, Italy
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47
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Theillet FX, Binolfi A, Frembgen-Kesner T, Hingorani K, Sarkar M, Kyne C, Li C, Crowley PB, Gierasch L, Pielak GJ, Elcock AH, Gershenson A, Selenko P. Physicochemical properties of cells and their effects on intrinsically disordered proteins (IDPs). Chem Rev 2014; 114:6661-714. [PMID: 24901537 PMCID: PMC4095937 DOI: 10.1021/cr400695p] [Citation(s) in RCA: 338] [Impact Index Per Article: 33.8] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Indexed: 02/07/2023]
Affiliation(s)
- Francois-Xavier Theillet
- Department
of NMR-supported Structural Biology, In-cell NMR Laboratory, Leibniz Institute of Molecular Pharmacology (FMP Berlin), Robert-Roessle Strasse 10, 13125 Berlin, Germany
| | - Andres Binolfi
- Department
of NMR-supported Structural Biology, In-cell NMR Laboratory, Leibniz Institute of Molecular Pharmacology (FMP Berlin), Robert-Roessle Strasse 10, 13125 Berlin, Germany
| | - Tamara Frembgen-Kesner
- Department
of Biochemistry, University of Iowa, Bowen Science Building, 51 Newton
Road, Iowa City, Iowa 52242, United States
| | - Karan Hingorani
- Departments
of Biochemistry & Molecular Biology and Chemistry, Program in
Molecular & Cellular Biology, University
of Massachusetts, Amherst, 240 Thatcher Way, Amherst, Massachusetts 01003, United States
| | - Mohona Sarkar
- Department
of Chemistry, Department of Biochemistry and Biophysics and Lineberger
Comprehensive Cancer Center, University
of North Carolina, Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
| | - Ciara Kyne
- School
of Chemistry, National University of Ireland,
Galway, University Road, Galway, Ireland
| | - Conggang Li
- Key Laboratory
of Magnetic Resonance in Biological Systems, State Key Laboratory
of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Center
for Magnetic Resonance, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, 430071, P.R. China
| | - Peter B. Crowley
- School
of Chemistry, National University of Ireland,
Galway, University Road, Galway, Ireland
| | - Lila Gierasch
- Departments
of Biochemistry & Molecular Biology and Chemistry, Program in
Molecular & Cellular Biology, University
of Massachusetts, Amherst, 240 Thatcher Way, Amherst, Massachusetts 01003, United States
| | - Gary J. Pielak
- Department
of Chemistry, Department of Biochemistry and Biophysics and Lineberger
Comprehensive Cancer Center, University
of North Carolina, Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
| | - Adrian H. Elcock
- Department
of Biochemistry, University of Iowa, Bowen Science Building, 51 Newton
Road, Iowa City, Iowa 52242, United States
| | - Anne Gershenson
- Departments
of Biochemistry & Molecular Biology and Chemistry, Program in
Molecular & Cellular Biology, University
of Massachusetts, Amherst, 240 Thatcher Way, Amherst, Massachusetts 01003, United States
| | - Philipp Selenko
- Department
of NMR-supported Structural Biology, In-cell NMR Laboratory, Leibniz Institute of Molecular Pharmacology (FMP Berlin), Robert-Roessle Strasse 10, 13125 Berlin, Germany
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48
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The mitochondrial disulfide relay system: roles in oxidative protein folding and beyond. Int J Cell Biol 2013; 2013:742923. [PMID: 24348563 PMCID: PMC3848088 DOI: 10.1155/2013/742923] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Accepted: 10/01/2013] [Indexed: 12/31/2022] Open
Abstract
Disulfide bond formation drives protein import of most proteins of the mitochondrial intermembrane space (IMS). The main components of this disulfide relay machinery are the oxidoreductase Mia40 and the sulfhydryl oxidase Erv1/ALR. Their precise functions have been elucidated in molecular detail for the yeast and human enzymes in vitro and in intact cells. However, we still lack knowledge on how Mia40 and Erv1/ALR impact cellular and organism physiology and whether they have functions beyond their role in disulfide bond formation. Here we summarize the principles of oxidation-dependent protein import mediated by the mitochondrial disulfide relay. We proceed by discussing recently described functions of Mia40 in the hypoxia response and of ALR in influencing mitochondrial morphology and its importance for tissue development and embryogenesis. We also include a discussion of the still mysterious function of Erv1/ALR in liver regeneration.
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49
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Affiliation(s)
- Anne Gershenson
- Department of Biochemistry and Molecular Biology, University of Massachusetts, Life Sciences Laboratory 240 Thatcher Way Amherst, MA 01003, USA.
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50
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Hewitt VL, Gabriel K, Traven A. The ins and outs of the intermembrane space: diverse mechanisms and evolutionary rewiring of mitochondrial protein import routes. Biochim Biophys Acta Gen Subj 2013; 1840:1246-53. [PMID: 23994494 DOI: 10.1016/j.bbagen.2013.08.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2013] [Revised: 08/09/2013] [Accepted: 08/20/2013] [Indexed: 11/24/2022]
Abstract
BACKGROUND Mitochondrial biogenesis is an essential process in all eukaryotes. Import of proteins from the cytosol into mitochondria is a key step in organelle biogenesis. Recent evidence suggests that a given mitochondrial protein does not take the same import route in all organisms, suggesting that pathways of mitochondrial protein import can be rewired through evolution. Examples of this process so far involve proteins destined to the mitochondrial intermembrane space (IMS). SCOPE OF REVIEW Here we review the components, substrates and energy sources of the known mechanisms of protein import into the IMS. We discuss evolutionary rewiring of the IMS import routes, focusing on the example of the lactate utilisation enzyme cytochrome b2 (Cyb2) in the model yeast Saccharomyces cerevisiae and the human fungal pathogen Candida albicans. MAJOR CONCLUSIONS There are multiple import pathways used for protein entry into the IMS and they form a network capable of importing a diverse range of substrates. These pathways have been rewired, possibly in response to environmental pressures, such as those found in the niches in the human body inhabited by C. albicans. GENERAL SIGNIFICANCE We propose that evolutionary rewiring of mitochondrial import pathways can adjust the metabolic fitness of a given species to their environmental niche. This article is part of a Special Issue entitled Frontiers of Mitochondrial.
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Affiliation(s)
- Victoria L Hewitt
- Department of Biochemistry and Molecular Biology, Building 77, Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne 3800, Australia.
| | - Kipros Gabriel
- Department of Biochemistry and Molecular Biology, Building 77, Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne 3800, Australia.
| | - Ana Traven
- Department of Biochemistry and Molecular Biology, Building 77, Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne 3800, Australia.
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