1
|
Pines O, Horwitz M, Herrmann JM. Privileged proteins with a second residence: dual targeting and conditional re-routing of mitochondrial proteins. FEBS J 2024. [PMID: 38857249 DOI: 10.1111/febs.17191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2024] [Revised: 04/15/2024] [Accepted: 05/22/2024] [Indexed: 06/12/2024]
Abstract
Almost all mitochondrial proteins are encoded by nuclear genes and synthesized in the cytosol as precursor proteins. Signals in the amino acid sequence of these precursors ensure their targeting and translocation into mitochondria. However, in many cases, only a certain fraction of a specific protein is transported into mitochondria, while the rest either remains in the cytosol or undergoes reverse translocation to the cytosol, and can populate other cellular compartments. This phenomenon is called dual localization which can be instigated by different mechanisms. These include alternative start or stop codons, differential transcripts, and ambiguous or competing targeting sequences. In many cases, dual localization might serve as an economic strategy to reduce the number of required genes; for example, when the same groups of enzymes are required both in mitochondria and chloroplasts or both in mitochondria and the nucleus/cytoplasm. Such cases frequently employ ambiguous targeting sequences to distribute proteins between both organelles. However, alternative localizations can also be used for signaling, for example when non-imported precursors serve as mitophagy signals or when they represent transcription factors in the nucleus to induce the mitochondrial unfolded stress response. This review provides an overview regarding the mechanisms and the physiological consequences of dual targeting.
Collapse
Affiliation(s)
- Ophry Pines
- Microbiology and Genetics, Faculty of Medicine, Hebrew University of Jerusalem, Israel
| | - Margalit Horwitz
- Microbiology and Genetics, Faculty of Medicine, Hebrew University of Jerusalem, Israel
| | | |
Collapse
|
2
|
Chen S, Collart MA. Membrane-associated mRNAs: A Post-transcriptional Pathway for Fine-turning Gene Expression. J Mol Biol 2024; 436:168579. [PMID: 38648968 DOI: 10.1016/j.jmb.2024.168579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 04/14/2024] [Accepted: 04/16/2024] [Indexed: 04/25/2024]
Abstract
Gene expression is a fundamental and highly regulated process involving a series of tightly coordinated steps, including transcription, post-transcriptional processing, translation, and post-translational modifications. A growing number of studies have revealed an additional layer of complexity in gene expression through the phenomenon of mRNA subcellular localization. mRNAs can be organized into membraneless subcellular structures within both the cytoplasm and the nucleus, but they can also targeted to membranes. In this review, we will summarize in particular our knowledge on localization of mRNAs to organelles, focusing on important regulators and available techniques for studying organellar localization, and significance of this localization in the broader context of gene expression regulation.
Collapse
Affiliation(s)
- Siyu Chen
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Institute of Genetics and Genomics of Geneva, Geneva, Switzerland.
| | - Martine A Collart
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Institute of Genetics and Genomics of Geneva, Geneva, Switzerland.
| |
Collapse
|
3
|
Mark M, Klein O, Zhang Y, Das K, Elbaz A, Hazan RN, Lichtenstein M, Lehming N, Schuldiner M, Pines O. Systematic Approaches to Study Eclipsed Targeting of Proteins Uncover a New Family of Mitochondrial Proteins. Cells 2023; 12:1550. [PMID: 37296670 PMCID: PMC10252432 DOI: 10.3390/cells12111550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Revised: 05/25/2023] [Accepted: 05/31/2023] [Indexed: 06/12/2023] Open
Abstract
Dual localization or dual targeting refers to the phenomenon by which identical, or almost identical, proteins are localized to two (or more) separate compartments of the cell. From previous work in the field, we had estimated that a third of the mitochondrial proteome is dual-targeted to extra-mitochondrial locations and suggested that this abundant dual targeting presents an evolutionary advantage. Here, we set out to study how many additional proteins whose main activity is outside mitochondria are also localized, albeit at low levels, to mitochondria (eclipsed). To do this, we employed two complementary approaches utilizing the α-complementation assay in yeast to uncover the extent of such an eclipsed distribution: one systematic and unbiased and the other based on mitochondrial targeting signal (MTS) predictions. Using these approaches, we suggest 280 new eclipsed distributed protein candidates. Interestingly, these proteins are enriched for distinctive properties compared to their exclusively mitochondrial-targeted counterparts. We focus on one unexpected eclipsed protein family of the Triose-phosphate DeHydrogenases (TDH) and prove that, indeed, their eclipsed distribution in mitochondria is important for mitochondrial activity. Our work provides a paradigm of deliberate eclipsed mitochondrial localization, targeting and function, and should expand our understanding of mitochondrial function in health and disease.
Collapse
Affiliation(s)
- Maayan Mark
- Department of Molecular Genetics and Microbiology, IMRIC, Faculty of Medicine, Hebrew University, Jerusalem 9112102, Israel; (M.M.); (K.D.); (A.E.); (R.N.H.)
| | - Ofir Klein
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel; (O.K.); (M.S.)
| | - Yu Zhang
- CREATE-NUS-HUJ Program and Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 138602, Singapore; (Y.Z.); (N.L.)
| | - Koyeli Das
- Department of Molecular Genetics and Microbiology, IMRIC, Faculty of Medicine, Hebrew University, Jerusalem 9112102, Israel; (M.M.); (K.D.); (A.E.); (R.N.H.)
| | - Adi Elbaz
- Department of Molecular Genetics and Microbiology, IMRIC, Faculty of Medicine, Hebrew University, Jerusalem 9112102, Israel; (M.M.); (K.D.); (A.E.); (R.N.H.)
| | - Reut Noa Hazan
- Department of Molecular Genetics and Microbiology, IMRIC, Faculty of Medicine, Hebrew University, Jerusalem 9112102, Israel; (M.M.); (K.D.); (A.E.); (R.N.H.)
| | - Michal Lichtenstein
- Department of Biochemistry and Molecular Biology, IMRIC, Faculty of Medicine, Hebrew University, Jerusalem 9112102, Israel;
| | - Norbert Lehming
- CREATE-NUS-HUJ Program and Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 138602, Singapore; (Y.Z.); (N.L.)
| | - Maya Schuldiner
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel; (O.K.); (M.S.)
| | - Ophry Pines
- Department of Molecular Genetics and Microbiology, IMRIC, Faculty of Medicine, Hebrew University, Jerusalem 9112102, Israel; (M.M.); (K.D.); (A.E.); (R.N.H.)
- CREATE-NUS-HUJ Program and Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 138602, Singapore; (Y.Z.); (N.L.)
| |
Collapse
|
4
|
Uszczynska-Ratajczak B, Sugunan S, Kwiatkowska M, Migdal M, Carbonell-Sala S, Sokol A, Winata CL, Chacinska A. Profiling subcellular localization of nuclear-encoded mitochondrial gene products in zebrafish. Life Sci Alliance 2022; 6:6/1/e202201514. [PMID: 36283702 PMCID: PMC9595208 DOI: 10.26508/lsa.202201514] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Revised: 09/30/2022] [Accepted: 10/04/2022] [Indexed: 11/08/2022] Open
Abstract
Most mitochondrial proteins are encoded by nuclear genes, synthetized in the cytosol and targeted into the organelle. To characterize the spatial organization of mitochondrial gene products in zebrafish (Danio rerio), we sequenced RNA from different cellular fractions. Our results confirmed the presence of nuclear-encoded mRNAs in the mitochondrial fraction, which in unperturbed conditions, are mainly transcripts encoding large proteins with specific properties, like transmembrane domains. To further explore the principles of mitochondrial protein compartmentalization in zebrafish, we quantified the transcriptomic changes for each subcellular fraction triggered by the chchd4a -/- mutation, causing the disorders in the mitochondrial protein import. Our results indicate that the proteostatic stress further restricts the population of transcripts on the mitochondrial surface, allowing only the largest and the most evolutionary conserved proteins to be synthetized there. We also show that many nuclear-encoded mitochondrial transcripts translated by the cytosolic ribosomes stay resistant to the global translation shutdown. Thus, vertebrates, in contrast to yeast, are not likely to use localized translation to facilitate synthesis of mitochondrial proteins under proteostatic stress conditions.
Collapse
Affiliation(s)
- Barbara Uszczynska-Ratajczak
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Poland .,Centre of New Technologies, University of Warsaw, Warsaw, Poland
| | - Sreedevi Sugunan
- ReMedy International Research Agenda Unit, University of Warsaw, Warsaw, Poland,International Institute of Molecular and Cell Biology, Warsaw, Poland
| | - Monika Kwiatkowska
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Poland,Centre of New Technologies, University of Warsaw, Warsaw, Poland,International Institute of Molecular and Cell Biology, Warsaw, Poland
| | - Maciej Migdal
- International Institute of Molecular and Cell Biology, Warsaw, Poland
| | - Silvia Carbonell-Sala
- Centre for Genomic Regulation, The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Anna Sokol
- Department of Developmental Genetics, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany,Biomolecular Mass Spectrometry, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Cecilia L Winata
- International Institute of Molecular and Cell Biology, Warsaw, Poland
| | - Agnieszka Chacinska
- ReMedy International Research Agenda Unit, IMol Polish Academy of Sciences, Warsaw, Poland
| |
Collapse
|
5
|
Avendaño-Monsalve MC, Mendoza-Martínez AE, Ponce-Rojas JC, Poot-Hernández AC, Rincón-Heredia R, Funes S. Positively charged amino acids at the N terminus of select mitochondrial proteins mediate early recognition by import proteins αβ'-NAC and Sam37. J Biol Chem 2022; 298:101984. [PMID: 35487246 PMCID: PMC9136113 DOI: 10.1016/j.jbc.2022.101984] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2021] [Revised: 04/16/2022] [Accepted: 04/19/2022] [Indexed: 11/04/2022] Open
Abstract
A major challenge in eukaryotic cells is the proper distribution of nuclear-encoded proteins to the correct organelles. For a subset of mitochondrial proteins, a signal sequence at the N terminus (matrix-targeting sequence [MTS]) is recognized by protein complexes to ensure their proper translocation into the organelle. However, the early steps of mitochondrial protein targeting remain undeciphered. The cytosolic chaperone nascent polypeptide–associated complex (NAC), which in yeast is represented as the two different heterodimers αβ-NAC and αβ′-NAC, has been proposed to be involved during the early steps of mitochondrial protein targeting. We have previously described that the mitochondrial outer membrane protein Sam37 interacts with αβ′-NAC and together promote the import of specific mitochondrial precursor proteins. In this work, we aimed to detect the region in the MTS of mitochondrial precursors relevant for their recognition by αβ′-NAC during their sorting to the mitochondria. We used targeting signals of different mitochondrial proteins (αβ′-NAC-dependent Oxa1 and αβ′-NAC-independent Mdm38) and fused them to GFP to study their intracellular localization by biochemical and microscopy methods, and in addition followed their import kinetics in vivo. Our results reveal the presence of a positively charged amino acid cluster in the MTS of select mitochondrial precursors, such as Oxa1 and Fum1, which are crucial for their recognition by αβ′-NAC. Furthermore, we explored the presence of this cluster at the N terminus of the mitochondrial proteome and propose a set of precursors whose proper localization depends on both αβ′-NAC and Sam37.
Collapse
Affiliation(s)
- Maria Clara Avendaño-Monsalve
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Coyoacán, Cd.Mx., Mexico
| | - Ariann E Mendoza-Martínez
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Coyoacán, Cd.Mx., Mexico
| | - José Carlos Ponce-Rojas
- Department of Molecular, Cellular, and Developmental Biology, University of California at Santa Barbara, Santa Barbara, California, USA
| | - Augusto César Poot-Hernández
- Unidad de Bioinformática y Manejo de la Información, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Coyoacán, Cd.Mx., Mexico
| | - Ruth Rincón-Heredia
- Unidad de Imagenología, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Coyoacán, Cd.Mx., Mexico
| | - Soledad Funes
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Coyoacán, Cd.Mx., Mexico.
| |
Collapse
|
6
|
Bogorodskiy A, Okhrimenko I, Maslov I, Maliar N, Burkatovskii D, von Ameln F, Schulga A, Jakobs P, Altschmied J, Haendeler J, Katranidis A, Sorokin I, Mishin A, Gordeliy V, Büldt G, Voos W, Gensch T, Borshchevskiy V. Accessing Mitochondrial Protein Import in Living Cells by Protein Microinjection. Front Cell Dev Biol 2021; 9:698658. [PMID: 34307376 PMCID: PMC8292824 DOI: 10.3389/fcell.2021.698658] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Accepted: 06/15/2021] [Indexed: 01/06/2023] Open
Abstract
Mitochondrial protein biogenesis relies almost exclusively on the expression of nuclear-encoded polypeptides. The current model postulates that most of these proteins have to be delivered to their final mitochondrial destination after their synthesis in the cytoplasm. However, the knowledge of this process remains limited due to the absence of proper experimental real-time approaches to study mitochondria in their native cellular environment. We developed a gentle microinjection procedure for fluorescent reporter proteins allowing a direct non-invasive study of protein transport in living cells. As a proof of principle, we visualized potential-dependent protein import into mitochondria inside intact cells in real-time. We validated that our approach does not distort mitochondrial morphology and preserves the endogenous expression system as well as mitochondrial protein translocation machinery. We observed that a release of nascent polypeptides chains from actively translating cellular ribosomes by puromycin strongly increased the import rate of the microinjected pre-protein. This suggests that a substantial amount of mitochondrial translocase complexes was involved in co-translational protein import of endogenously expressed pre-proteins. Our protein microinjection method opens new possibilities to study the role of mitochondrial protein import in cell models of various pathological conditions as well as aging processes.
Collapse
Affiliation(s)
- Andrey Bogorodskiy
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny, Russia
| | - Ivan Okhrimenko
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny, Russia
| | - Ivan Maslov
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny, Russia
| | - Nina Maliar
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny, Russia
| | - Dmitrii Burkatovskii
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny, Russia
| | - Florian von Ameln
- Environmentally-Induced Cardiovascular Degeneration, Central Institute of Clinical Chemistry and Laboratory Medicine, Medical Faculty, University Hospital and Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
- IUF–Leibniz Research Institute for Environmental Medicine, Düsseldorf, Germany
| | - Alexey Schulga
- Molecular Immunology Laboratory, Shemyakin & Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - Philipp Jakobs
- Environmentally-Induced Cardiovascular Degeneration, Central Institute of Clinical Chemistry and Laboratory Medicine, Medical Faculty, University Hospital and Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Joachim Altschmied
- Environmentally-Induced Cardiovascular Degeneration, Central Institute of Clinical Chemistry and Laboratory Medicine, Medical Faculty, University Hospital and Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
- IUF–Leibniz Research Institute for Environmental Medicine, Düsseldorf, Germany
| | - Judith Haendeler
- Environmentally-Induced Cardiovascular Degeneration, Central Institute of Clinical Chemistry and Laboratory Medicine, Medical Faculty, University Hospital and Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Alexandros Katranidis
- Institute of Biological Information Processing (IBI-6: Cellular Structural Biology), Forschungszentrum Jülich, Jülich, Germany
| | - Ivan Sorokin
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny, Russia
- Institute of Protein Research, Russian Academy of Sciences, Pushchino, Russia
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia
| | - Alexey Mishin
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny, Russia
| | - Valentin Gordeliy
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny, Russia
- Institute of Biological Information Processing (IBI-7: Structural Biochemistry), Forschungszentrum Jülich, Jülich, Germany
- JuStruct: Jülich Center for Structural Biology, Forschungszentrum Jülich, Jülich, Germany
- Institut de Biologie Structurale (IBS), Université Grenoble Alpes, CEA, CNRS, Grenoble, France
| | - Georg Büldt
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny, Russia
| | - Wolfgang Voos
- Institute of Biochemistry and Molecular Biology (IBMB), Faculty of Medicine, University of Bonn, Bonn, Germany
| | - Thomas Gensch
- Institute of Biological Information Processing (IBI-1: Molecular and Cellular Physiology), Forschungszentrum Jülich, Jülich, Germany
| | - Valentin Borshchevskiy
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny, Russia
- Institute of Biological Information Processing (IBI-7: Structural Biochemistry), Forschungszentrum Jülich, Jülich, Germany
- JuStruct: Jülich Center for Structural Biology, Forschungszentrum Jülich, Jülich, Germany
| |
Collapse
|
7
|
Avendaño-Monsalve MC, Ponce-Rojas JC, Funes S. From cytosol to mitochondria: the beginning of a protein journey. Biol Chem 2020; 401:645-661. [DOI: 10.1515/hsz-2020-0110] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Accepted: 02/24/2020] [Indexed: 01/18/2023]
Abstract
AbstractMitochondrial protein import is one of the key processes during mitochondrial biogenesis that involves a series of events necessary for recognition and delivery of nucleus-encoded/cytosol-synthesized mitochondrial proteins into the organelle. The past research efforts have mainly unraveled how membrane translocases ensure the correct protein sorting within the different mitochondrial subcompartments. However, early steps of recognition and delivery remain relatively uncharacterized. In this review, we discuss our current understanding about the signals on mitochondrial proteins, as well as in the mRNAs encoding them, which with the help of cytosolic chaperones and membrane receptors support protein targeting to the organelle in order to avoid improper localization. In addition, we discuss recent findings that illustrate how mistargeting of mitochondrial proteins triggers stress responses, aiming to restore cellular homeostasis.
Collapse
Affiliation(s)
- Maria Clara Avendaño-Monsalve
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Circuito Exterior s/n Ciudad Universitaria Coyoacán, México, Cd.Mx. 04510, Mexico
| | - José Carlos Ponce-Rojas
- Department of Molecular, Cellular, and Developmental Biology, University of California at Santa Barbara, Santa Barbara, CA 93106-9625, USA
| | - Soledad Funes
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Circuito Exterior s/n Ciudad Universitaria Coyoacán, México, Cd.Mx. 04510, Mexico
| |
Collapse
|
8
|
Saladi S, Boos F, Poglitsch M, Meyer H, Sommer F, Mühlhaus T, Schroda M, Schuldiner M, Madeo F, Herrmann JM. The NADH Dehydrogenase Nde1 Executes Cell Death after Integrating Signals from Metabolism and Proteostasis on the Mitochondrial Surface. Mol Cell 2020; 77:189-202.e6. [DOI: 10.1016/j.molcel.2019.09.027] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2019] [Revised: 08/16/2019] [Accepted: 09/23/2019] [Indexed: 12/22/2022]
|
9
|
De Nijs Y, De Maeseneire SL, Soetaert WK. 5' untranslated regions: the next regulatory sequence in yeast synthetic biology. Biol Rev Camb Philos Soc 2019; 95:517-529. [PMID: 31863552 DOI: 10.1111/brv.12575] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Revised: 11/08/2019] [Accepted: 11/28/2019] [Indexed: 01/10/2023]
Abstract
When developing industrial biotechnology processes, Saccharomyces cerevisiae (baker's yeast or brewer's yeast) is a popular choice as a microbial host. Many tools have been developed in the fields of synthetic biology and metabolic engineering to introduce heterologous pathways and tune their expression in yeast. Such tools mainly focus on controlling transcription, whereas post-transcriptional regulation is often overlooked. Herein we discuss regulatory elements found in the 5' untranslated region (UTR) and their influence on protein synthesis. We provide not only an overall picture, but also a set of design rules on how to engineer a 5' UTR. The reader is also referred to currently available models that allow gene expression to be tuned predictably using different 5' UTRs.
Collapse
Affiliation(s)
- Yatti De Nijs
- Faculty of Bioscience Engineering, Centre for Industrial Biotechnology and Biocatalysis (InBio.be), Department Biotechnology, Ghent University, Coupure Links 653, 9000, Ghent, Belgium
| | - Sofie L De Maeseneire
- Faculty of Bioscience Engineering, Centre for Industrial Biotechnology and Biocatalysis (InBio.be), Department Biotechnology, Ghent University, Coupure Links 653, 9000, Ghent, Belgium
| | - Wim K Soetaert
- Faculty of Bioscience Engineering, Centre for Industrial Biotechnology and Biocatalysis (InBio.be), Department Biotechnology, Ghent University, Coupure Links 653, 9000, Ghent, Belgium
| |
Collapse
|
10
|
Saatchi F, Kirchmaier AL. Tolerance of DNA Replication Stress Is Promoted by Fumarate Through Modulation of Histone Demethylation and Enhancement of Replicative Intermediate Processing in Saccharomyces cerevisiae. Genetics 2019; 212:631-654. [PMID: 31123043 PMCID: PMC6614904 DOI: 10.1534/genetics.119.302238] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2018] [Accepted: 05/07/2019] [Indexed: 12/28/2022] Open
Abstract
Fumarase is a well-characterized TCA cycle enzyme that catalyzes the reversible conversion of fumarate to malate. In mammals, fumarase acts as a tumor suppressor, and loss-of-function mutations in the FH gene in hereditary leiomyomatosis and renal cell cancer result in the accumulation of intracellular fumarate-an inhibitor of α-ketoglutarate-dependent dioxygenases. Fumarase promotes DNA repair by nonhomologous end joining in mammalian cells through interaction with the histone variant H2A.Z, and inhibition of KDM2B, a H3 K36-specific histone demethylase. Here, we report that Saccharomyces cerevisiae fumarase, Fum1p, acts as a response factor during DNA replication stress, and fumarate enhances survival of yeast lacking Htz1p (H2A.Z in mammals). We observed that exposure to DNA replication stress led to upregulation as well as nuclear enrichment of Fum1p, and raising levels of fumarate in cells via deletion of FUM1 or addition of exogenous fumarate suppressed the sensitivity to DNA replication stress of htz1Δ mutants. This suppression was independent of modulating nucleotide pool levels. Rather, our results are consistent with fumarate conferring resistance to DNA replication stress in htz1Δ mutants by inhibiting the H3 K4-specific histone demethylase Jhd2p, and increasing H3 K4 methylation. Although the timing of checkpoint activation and deactivation remained largely unaffected by fumarate, sensors and mediators of the DNA replication checkpoint were required for fumarate-dependent resistance to replication stress in the htz1Δ mutants. Together, our findings imply metabolic enzymes and metabolites aid in processing replicative intermediates by affecting chromatin modification states, thereby promoting genome integrity.
Collapse
Affiliation(s)
- Faeze Saatchi
- Department of Biochemistry, Purdue University, West Lafayette, Indiana 47907
- Purdue University Center for Cancer Research, Purdue University, West Lafayette, Indiana 47907
- Bindley Bioscience Center, Purdue University, West Lafayette, Indiana 47907
| | - Ann L Kirchmaier
- Department of Biochemistry, Purdue University, West Lafayette, Indiana 47907
- Purdue University Center for Cancer Research, Purdue University, West Lafayette, Indiana 47907
- Bindley Bioscience Center, Purdue University, West Lafayette, Indiana 47907
| |
Collapse
|
11
|
Jarmolinska AI, Perlinska AP, Runkel R, Trefz B, Ginn HM, Virnau P, Sulkowska JI. Proteins' Knotty Problems. J Mol Biol 2018; 431:244-257. [PMID: 30391297 DOI: 10.1016/j.jmb.2018.10.012] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2018] [Revised: 10/17/2018] [Accepted: 10/17/2018] [Indexed: 12/20/2022]
Abstract
Knots in proteins are increasingly being recognized as an important structural concept, and the folding of these peculiar structures still poses considerable challenges. From a functional point of view, most protein knots discovered so far are either enzymes or DNA-binding proteins. Our comprehensive topological analysis of the Protein Data Bank reveals several novel structures including knotted mitochondrial proteins and the most deeply embedded protein knot discovered so far. For the latter, we propose a novel folding pathway based on the idea that a loose knot forms at a terminus and slides to its native position. For the mitochondrial proteins, we discuss the folding problem from the perspective of transport and suggest that they fold inside the mitochondria. We also discuss the evolutionary origin of a novel class of knotted membrane proteins and argue that a novel knotted DNA-binding protein constitutes a new fold. Finally, we have also discovered a knot in an artificially designed protein structure.
Collapse
Affiliation(s)
- Aleksandra I Jarmolinska
- Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097 Warsaw, Poland; College of Inter-Faculty Individual Studies in Mathematics and Natural Sciences, Banacha 2c, 02-097 Warsaw, Poland
| | - Agata P Perlinska
- Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097 Warsaw, Poland; College of Inter-Faculty Individual Studies in Mathematics and Natural Sciences, Banacha 2c, 02-097 Warsaw, Poland
| | - Robert Runkel
- Department of Physics, Johannes Gutenberg University Mainz, Staudingerweg 7, 55128 Mainz, Germany
| | - Benjamin Trefz
- Department of Physics, Johannes Gutenberg University Mainz, Staudingerweg 7, 55128 Mainz, Germany; Graduate School Material Science in Mainz, Staudinger Weg 9, 55128 Mainz, Germany
| | - Helen M Ginn
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Peter Virnau
- Department of Physics, Johannes Gutenberg University Mainz, Staudingerweg 7, 55128 Mainz, Germany
| | - Joanna I Sulkowska
- Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097 Warsaw, Poland.
| |
Collapse
|
12
|
Weill U, Yofe I, Sass E, Stynen B, Davidi D, Natarajan J, Ben-Menachem R, Avihou Z, Goldman O, Harpaz N, Chuartzman S, Kniazev K, Knoblach B, Laborenz J, Boos F, Kowarzyk J, Ben-Dor S, Zalckvar E, Herrmann JM, Rachubinski RA, Pines O, Rapaport D, Michnick SW, Levy ED, Schuldiner M. Genome-wide SWAp-Tag yeast libraries for proteome exploration. Nat Methods 2018; 15:617-622. [PMID: 29988094 PMCID: PMC6076999 DOI: 10.1038/s41592-018-0044-9] [Citation(s) in RCA: 97] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Accepted: 05/10/2018] [Indexed: 12/31/2022]
Abstract
Yeast libraries revolutionized the systematic study of cell biology. To extensively increase the number of such libraries and the type of information that can be gleaned from them, we previously devised the SWAp-Tag (SWAT) approach that enables rapid, easy and efficient creation of yeast strain collections. Here we present the construction and investigation of a full genome library of ~5500 strains carrying the SWAT NOP1promoter-GFP module at the N terminus of proteins, as well as its use in creating six additional libraries that either restore the native regulation, create an overexpression library with a Cherry tag or enable protein complementation assays from two fragments of an enzyme or fluorophore. We show methods to utilize these SWAT collections to systematically characterize the yeast proteome on multiple levels spanning protein abundance, localization, topology and interactions. Our findings demonstrate how diverse full-genome SWAT libraries facilitate obtaining insights into numerous aspects of the proteome.
Collapse
Affiliation(s)
- Uri Weill
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Ido Yofe
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Ehud Sass
- Department of Structural Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Bram Stynen
- Département de Biochimie, Faculté de Médecine, Université de Montréal, Montreal, QC, Canada
| | - Dan Davidi
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Janani Natarajan
- Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, Germany
| | - Reut Ben-Menachem
- Department of Microbiology and Molecular Genetics, IMRIC, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Zohar Avihou
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Omer Goldman
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Nofar Harpaz
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Silvia Chuartzman
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Kiril Kniazev
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Barbara Knoblach
- Department of Cell Biology, University of Alberta, Edmonton, AB, Canada
| | - Janina Laborenz
- Department of Cell Biology, University of Kaiserslautern, Kaiserslautern, Germany
| | - Felix Boos
- Department of Cell Biology, University of Kaiserslautern, Kaiserslautern, Germany
| | - Jacqueline Kowarzyk
- Département de Biochimie, Faculté de Médecine, Université de Montréal, Montreal, QC, Canada
| | - Shifra Ben-Dor
- Department of Life Sciences Core Facilities, Weizmann Institute of Science, Rehovot, Israel
| | - Einat Zalckvar
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Johannes M Herrmann
- Department of Cell Biology, University of Kaiserslautern, Kaiserslautern, Germany
| | | | - Ophry Pines
- Department of Microbiology and Molecular Genetics, IMRIC, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Doron Rapaport
- Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, Germany
| | - Stephen W Michnick
- Département de Biochimie, Faculté de Médecine, Université de Montréal, Montreal, QC, Canada
| | - Emmanuel D Levy
- Department of Structural Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Maya Schuldiner
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel.
| |
Collapse
|
13
|
Affiliation(s)
- Tobias Jores
- Interfaculty Institute of Biochemistry; University of Tuebingen; Germany
| | - Doron Rapaport
- Interfaculty Institute of Biochemistry; University of Tuebingen; Germany
| |
Collapse
|
14
|
Golani-Armon A, Arava Y. Localization of Nuclear-Encoded mRNAs to Mitochondria Outer Surface. BIOCHEMISTRY (MOSCOW) 2017; 81:1038-1043. [PMID: 27908229 DOI: 10.1134/s0006297916100023] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The diverse functions of mitochondria depend on hundreds of different proteins. The vast majority of these proteins is encoded in the nucleus, translated in the cytosol, and must be imported into the organelle. Import was shown to occur after complete synthesis of the protein, with the assistance of cytosolic chaperones that maintain it in an unfolded state and target it to the mitochondrial translocase of the outer membrane (TOM complex). Recent studies, however, identified many mRNAs encoding mitochondrial proteins near the outer membrane of mitochondria. Translation studies suggest that many of these mRNAs are translated locally, presumably allowing cotranslational import into mitochondria. Herein we review these data and discuss its relevance for local protein synthesis. We also suggest alternative roles for mRNA localization to mitochondria. Finally, we suggest future research directions, including revealing the significance of localization to mitochondria physiology and the molecular players that regulate it.
Collapse
Affiliation(s)
- A Golani-Armon
- Technion - Israel Institute of Technology, Faculty of Biology, Haifa, 32000, Israel.
| | | |
Collapse
|
15
|
Demishtein-Zohary K, Azem A. The TIM23 mitochondrial protein import complex: function and dysfunction. Cell Tissue Res 2016; 367:33-41. [DOI: 10.1007/s00441-016-2486-7] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Accepted: 08/05/2016] [Indexed: 01/16/2023]
|
16
|
Import of a major mitochondrial enzyme depends on synergy between two distinct helices of its presequence. Biochem J 2016; 473:2813-29. [PMID: 27422783 PMCID: PMC5095901 DOI: 10.1042/bcj20160535] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Accepted: 07/15/2016] [Indexed: 12/13/2022]
Abstract
Mammalian glutamate dehydrogenase (GDH), a nuclear-encoded enzyme central to cellular metabolism, is among the most abundant mitochondrial proteins (constituting up to 10% of matrix proteins). To attain such high levels, GDH depends on very efficient mitochondrial targeting that, for human isoenzymes hGDH1 and hGDH2, is mediated by an unusually long cleavable presequence (N53). Here, we studied the mitochondrial transport of these proteins using isolated yeast mitochondria and human cell lines. We found that both hGDHs were very rapidly imported and processed in isolated mitochondria, with their presequences (N53) alone being capable of directing non-mitochondrial proteins into mitochondria. These presequences were predicted to form two α helices (α1: N 1–10; α2: N 16–32) separated by loops. Selective deletion of the α1 helix abolished the mitochondrial import of hGDHs. While the α1 helix alone had a very weak hGDH mitochondrial import capacity, it could direct efficiently non-mitochondrial proteins into mitochondria. In contrast, the α2 helix had no autonomous mitochondrial-targeting capacity. A peptide consisting of α1 and α2 helices without intervening sequences had GDH transport efficiency comparable with that of N53. Mutagenesis of the cleavage site blocked the intra-mitochondrial processing of hGDHs, but did not affect their mitochondrial import. Replacement of all three positively charged N-terminal residues (Arg3, Lys7 and Arg13) by Ala abolished import. We conclude that the synergistic interaction of helices α1 and α2 is crucial for the highly efficient import of hGDHs into mitochondria.
Collapse
|
17
|
Abstract
Local synthesis of proteins near their activity site has been demonstrated in many biological systems, and has diverse contributions to cellular functions. Studies in recent years have revealed that hundreds of mitochondria-destined proteins are synthesized by cytosolic ribosomes near the mitochondrial outer membrane, indicating that localized translation also occurs at this cellular locus. Furthermore, in the last year central factors that are involved in this process were identified in yeast, Drosophila, and human cells. Herein we review the experimental evidence for localized translation on the cytosolic side of the mitochondrial outer membrane; in addition, we describe the factors that are involved in this process and discuss the conservation of this mechanism among various species. We also describe the relationship between localized translation and import into the mitochondria and suggest avenues of study that look beyond cotranslational import. Finally we discuss future challenges in characterizing the mechanisms for localized translation and its physiological significance.
Collapse
Affiliation(s)
- Chen Lesnik
- a Department of Biology ; Technion - Israel Institute of Technology ; Haifa , Israel
| | | | | |
Collapse
|
18
|
Dik E, Naamati A, Asraf H, Lehming N, Pines O. Human Fumarate Hydratase Is Dual Localized by an Alternative Transcription Initiation Mechanism. Traffic 2016; 17:720-32. [DOI: 10.1111/tra.12397] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Revised: 03/29/2016] [Accepted: 03/29/2016] [Indexed: 12/11/2022]
Affiliation(s)
- Ekaterina Dik
- Department of Microbiology Molecular Genetics, IMRIC, Faculty of Medicine; Hebrew University of Jerusalem; Jerusalem Israel
| | - Adi Naamati
- Department of Microbiology Molecular Genetics, IMRIC, Faculty of Medicine; Hebrew University of Jerusalem; Jerusalem Israel
| | - Hadar Asraf
- Department of Microbiology Molecular Genetics, IMRIC, Faculty of Medicine; Hebrew University of Jerusalem; Jerusalem Israel
| | - Norbert Lehming
- CREATE-NUS-HUJ Program and the Department of Microbiology, Yong Loo Lin School of Medicine; National University of Singapore; Singapore Singapore
| | - Ophry Pines
- Department of Microbiology Molecular Genetics, IMRIC, Faculty of Medicine; Hebrew University of Jerusalem; Jerusalem Israel
- CREATE-NUS-HUJ Program and the Department of Microbiology, Yong Loo Lin School of Medicine; National University of Singapore; Singapore Singapore
| |
Collapse
|
19
|
Zabezhinsky D, Slobodin B, Rapaport D, Gerst JE. An Essential Role for COPI in mRNA Localization to Mitochondria and Mitochondrial Function. Cell Rep 2016; 15:540-549. [PMID: 27068463 DOI: 10.1016/j.celrep.2016.03.053] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Revised: 09/20/2015] [Accepted: 03/14/2016] [Indexed: 10/22/2022] Open
Abstract
Nuclear-encoded mRNAs encoding mitochondrial proteins (mMPs) can localize directly to the mitochondrial surface, yet how mMPs target mitochondria and whether RNA targeting contributes to protein import into mitochondria and cellular metabolism are unknown. Here, we show that the COPI vesicle coat complex is necessary for mMP localization to mitochondria and mitochondrial function. COPI inactivation leads to reduced mMP binding to COPI itself, resulting in the dissociation of mMPs from mitochondria, a reduction in mitochondrial membrane potential, a decrease in protein import in vivo and in vitro, and severe deficiencies in mitochondrial respiration. Using a model mMP (OXA1), we observed that COPI inactivation (or mutation of the potential COPI-interaction site) led to altered mRNA localization and impaired cellular respiration. Overall, COPI-mediated mMP targeting is critical for mitochondrial protein import and function, and transcript delivery to the mitochondria or endoplasmic reticulum is regulated by cis-acting RNA sequences and trans-acting proteins.
Collapse
Affiliation(s)
- Dmitry Zabezhinsky
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Boris Slobodin
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Doron Rapaport
- Interfaculty Institute of Biochemistry, University of Tuebingen, Hoppe-Seyler-Strasse 4, 72076 Tuebingen, Germany
| | - Jeffrey E Gerst
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel.
| |
Collapse
|
20
|
The Design and Structure of Outer Membrane Receptors from Peroxisomes, Mitochondria, and Chloroplasts. Structure 2015; 23:1783-1800. [DOI: 10.1016/j.str.2015.08.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Revised: 07/20/2015] [Accepted: 08/10/2015] [Indexed: 01/03/2023]
|
21
|
Polledo JM, Cervini G, Romaniuk MA, Cassola A. Interactions between RNA-binding proteins and P32 homologues in trypanosomes and human cells. Curr Genet 2015; 62:203-12. [PMID: 26385742 DOI: 10.1007/s00294-015-0519-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Revised: 09/09/2015] [Accepted: 09/10/2015] [Indexed: 12/25/2022]
Abstract
RNA-binding proteins (RBPs) are involved in many aspects of mRNA metabolism such as splicing, nuclear export, translation, silencing, and decay. To cope with these tasks, these proteins use specialized domains such as the RNA recognition motif (RRM), the most abundant and widely spread RNA-binding domain. Although this domain was first described as a dedicated RNA-binding moiety, current evidence indicates these motifs can also engage in direct protein-protein interactions. Here, we discuss recent evidence describing the interaction between the RRM of the trypanosomatid RBP UBP1 and P22, the homolog of the human multifunctional protein P32/C1QBP. Human P32 was also identified while performing a similar interaction screening using both RRMs of TDP-43, an RBP involved in splicing regulation and Amyotrophic Lateral Sclerosis. Furthermore, we show that this interaction is mediated by RRM1. The relevance of this interaction is discussed in the context of recent TDP-43 interactomic approaches that identified P32, and the numerous evidences supporting interactions between P32 and RBPs. Finally, we discuss the vast universe of interactions involving P32, supporting its role as a molecular chaperone regulating the function of its ligands.
Collapse
Affiliation(s)
- Juan Manuel Polledo
- Instituto de Investigaciones Biotecnológicas-Instituto Tecnológico de Chascomús, UNSAM-CONICET, Buenos Aires, Argentina
| | - Gabriela Cervini
- Instituto de Investigaciones Biotecnológicas-Instituto Tecnológico de Chascomús, UNSAM-CONICET, Buenos Aires, Argentina
| | - María Albertina Romaniuk
- Instituto de Investigaciones Biotecnológicas-Instituto Tecnológico de Chascomús, UNSAM-CONICET, Buenos Aires, Argentina
| | - Alejandro Cassola
- Instituto de Investigaciones Biotecnológicas-Instituto Tecnológico de Chascomús, UNSAM-CONICET, Buenos Aires, Argentina.
| |
Collapse
|
22
|
Bankapalli K, Saladi S, Awadia SS, Goswami AV, Samaddar M, D'Silva P. Robust glyoxalase activity of Hsp31, a ThiJ/DJ-1/PfpI family member protein, is critical for oxidative stress resistance in Saccharomyces cerevisiae. J Biol Chem 2015; 290:26491-507. [PMID: 26370081 DOI: 10.1074/jbc.m115.673624] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Indexed: 11/06/2022] Open
Abstract
Methylglyoxal (MG) is a reactive metabolic intermediate generated during various cellular biochemical reactions, including glycolysis. The accumulation of MG indiscriminately modifies proteins, including important cellular antioxidant machinery, leading to severe oxidative stress, which is implicated in multiple neurodegenerative disorders, aging, and cardiac disorders. Although cells possess efficient glyoxalase systems for detoxification, their functions are largely dependent on the glutathione cofactor, the availability of which is self-limiting under oxidative stress. Thus, higher organisms require alternate modes of reducing the MG-mediated toxicity and maintaining redox balance. In this report, we demonstrate that Hsp31 protein, a member of the ThiJ/DJ-1/PfpI family in Saccharomyces cerevisiae, plays an indispensable role in regulating redox homeostasis. Our results show that Hsp31 possesses robust glutathione-independent methylglyoxalase activity and suppresses MG-mediated toxicity and ROS levels as compared with another paralog, Hsp34. On the other hand, glyoxalase-defective mutants of Hsp31 were found highly compromised in regulating the ROS levels. Additionally, Hsp31 maintains cellular glutathione and NADPH levels, thus conferring protection against oxidative stress, and Hsp31 relocalizes to mitochondria to provide cytoprotection to the organelle under oxidative stress conditions. Importantly, human DJ-1, which is implicated in the familial form of Parkinson disease, complements the function of Hsp31 by suppressing methylglyoxal and oxidative stress, thus signifying the importance of these proteins in the maintenance of ROS homeostasis across phylogeny.
Collapse
Affiliation(s)
- Kondalarao Bankapalli
- From the Department of Biochemistry, Indian Institute of Science, Bangalore, Karnataka 560012, India
| | - SreeDivya Saladi
- From the Department of Biochemistry, Indian Institute of Science, Bangalore, Karnataka 560012, India
| | - Sahezeel S Awadia
- From the Department of Biochemistry, Indian Institute of Science, Bangalore, Karnataka 560012, India
| | - Arvind Vittal Goswami
- From the Department of Biochemistry, Indian Institute of Science, Bangalore, Karnataka 560012, India
| | - Madhuja Samaddar
- From the Department of Biochemistry, Indian Institute of Science, Bangalore, Karnataka 560012, India
| | - Patrick D'Silva
- From the Department of Biochemistry, Indian Institute of Science, Bangalore, Karnataka 560012, India
| |
Collapse
|
23
|
Kalderon B, Kogan G, Bubis E, Pines O. Cytosolic Hsp60 can modulate proteasome activity in yeast. J Biol Chem 2014; 290:3542-51. [PMID: 25525272 DOI: 10.1074/jbc.m114.626622] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Hsp60, an essential oligomeric molecular mitochondrial chaperone, has been subject to rigorous basic and clinical research. With yeast as a model system, we provide evidence for the ability of cytosolic yHsp60 to inhibit the yeast proteasome. (i) Following biological turnover of murine Bax (a proteasome substrate), we show that co-expression of cytosolic yHsp60 stabilizes Bax, enhances its association with mitochondria, and enhances its killing capacity. (ii) Expression of yHsp60 in the yeast cytosol (yHsp60c) inhibits degradation of a cytosolic protein ΔMTS-Aco1 tagged with the degron SL17 (a ubiquitin-proteasome substrate). (iii) Conditions under which Hsp60 accumulates in the cytosol (elevated Hsp60c or growth at 37 °C) correlate with reduced 20 S peptidase activity in proteasomes purified from cell extracts. (iv) Elevated yHsp60 in the cytosol correlate with accumulation of polyubiquitinated proteins. (v) According to 20 S proteasome pulldown experiments, Hsp60 is physically associated with proteasomes in extracts of cells expressing Hsp60c or grown at 37 °C. Even mutant Hsp60 proteins, lacking chaperone activity, were still capable of proteasome inhibition. The results support the hypothesis that localization of Hsp60 to the cytosol may modulate proteasome activity according to cell need.
Collapse
Affiliation(s)
- Bella Kalderon
- From the Department of Microbiology Molecular Genetics, IMRIC, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 91120, Israel and
| | - Gleb Kogan
- From the Department of Microbiology Molecular Genetics, IMRIC, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 91120, Israel and
| | - Ettel Bubis
- From the Department of Microbiology Molecular Genetics, IMRIC, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 91120, Israel and
| | - Ophry Pines
- From the Department of Microbiology Molecular Genetics, IMRIC, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 91120, Israel and the CREATE-NUS-HUJ Program, National University of Singapore, 138602 Singapore
| |
Collapse
|
24
|
Kisslov I, Naamati A, Shakarchy N, Pines O. Dual-targeted proteins tend to be more evolutionarily conserved. Mol Biol Evol 2014; 31:2770-9. [PMID: 25063438 DOI: 10.1093/molbev/msu221] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
In eukaryotic cells, identical proteins can be located in more than a single subcellular compartment, a phenomenon termed dual targeting. We hypothesized that dual-targeted proteins should be more evolutionary conserved than exclusive mitochondrial proteins, due to separate selective pressures administered by the different compartments to maintain the functions associated with the protein sequences. We employed codon usage bias, propensity for gene loss, phylogenetic relationships, conservation analysis at the DNA level, and gene expression, to test our hypothesis. Our findings indicate that, indeed, dual-targeted proteins are significantly more conserved than their exclusively targeted counterparts. We then used this trait of gene conservation, together with previously identified traits of dual-targeted proteins (such as protein net charge and mitochondrial targeting sequence strength) to 1) create, for the first time (due to addition of conservation parameters), a tool for the prediction of dual-targeted mitochondrial proteins based on protein and mRNA sequences, and 2) show that molecular mechanisms involving one versus two translation products are not correlated with specific dual-targeting parameters. Finally, we discuss what evolutionary pressure maintains protein dual targeting in eukaryotes and deduce, as we initially hypothesized, that it is the discrete functions of these proteins in the different subcellular compartments, regardless of their dual-targeting mechanism.
Collapse
Affiliation(s)
- Irit Kisslov
- Department of Microbiology Molecular Genetics, IMRIC, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Adi Naamati
- Department of Microbiology Molecular Genetics, IMRIC, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel Department of Microbiology Molecular Genetics, IMRIC, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Nitzan Shakarchy
- Department of Microbiology Molecular Genetics, IMRIC, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Ophry Pines
- Department of Microbiology Molecular Genetics, IMRIC, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel CREATE-NUS-HUJ Cellular & Molecular Mechanisms of Inflammation Program, National University of Singapore, Singapore
| |
Collapse
|
25
|
Xu G, Chen X, Liu L, Jiang L. Fumaric acid production in Saccharomyces cerevisiae by simultaneous use of oxidative and reductive routes. BIORESOURCE TECHNOLOGY 2013; 148:91-96. [PMID: 24045196 DOI: 10.1016/j.biortech.2013.08.115] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2013] [Revised: 08/16/2013] [Accepted: 08/19/2013] [Indexed: 05/28/2023]
Abstract
In this study, the simultaneous use of reductive and oxidative routes to produce fumaric acid was explored. The strain FMME003 (Saccharomyces cerevisiae CEN.PK2-1CΔTHI2) exhibited capability to accumulate pyruvate and was used for fumaric acid production. The fum1 mutant FMME004 could produce fumaric acid via oxidative route, but the introduction of reductive route derived from Rhizopus oryzae NRRL 1526 led to lower fumaric acid production. Analysis of the key factors associated with fumaric acid production revealed that pyruvate carboxylase had a low degree of control over the carbon flow to malic acid. The fumaric acid titer was improved dramatically when the heterologous gene RoPYC was overexpressed and 32 μg/L of biotin was added. Furthermore, under the optimal carbon/nitrogen ratio, the engineered strain FMME004-6 could produce up to 5.64 ± 0.16 g/L of fumaric acid. These results demonstrated that the proposed fermentative method is efficient for fumaric acid production.
Collapse
Affiliation(s)
- Guoqiang Xu
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China; National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, Wuxi 214122, China; The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | | | | | | |
Collapse
|
26
|
Gispert S, Parganlija D, Klinkenberg M, Dröse S, Wittig I, Mittelbronn M, Grzmil P, Koob S, Hamann A, Walter M, Büchel F, Adler T, Hrabé de Angelis M, Busch DH, Zell A, Reichert AS, Brandt U, Osiewacz HD, Jendrach M, Auburger G. Loss of mitochondrial peptidase Clpp leads to infertility, hearing loss plus growth retardation via accumulation of CLPX, mtDNA and inflammatory factors. Hum Mol Genet 2013; 22:4871-87. [PMID: 23851121 PMCID: PMC7108587 DOI: 10.1093/hmg/ddt338] [Citation(s) in RCA: 143] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The caseinolytic peptidase P (CLPP) is conserved from bacteria to humans. In the mitochondrial matrix, it multimerizes and forms a macromolecular proteasome-like cylinder together with the chaperone CLPX. In spite of a known relevance for the mitochondrial unfolded protein response, its substrates and tissue-specific roles are unclear in mammals. Recessive CLPP mutations were recently observed in the human Perrault variant of ovarian failure and sensorineural hearing loss. Here, a first characterization of CLPP null mice demonstrated complete female and male infertility and auditory deficits. Disrupted spermatogenesis already at the spermatid stage and ovarian follicular differentiation failure were evident. Reduced pre-/post-natal survival and marked ubiquitous growth retardation contrasted with only light impairment of movement and respiratory activities. Interestingly, the mice showed resistance to ulcerative dermatitis. Systematic expression studies detected up-regulation of other mitochondrial chaperones, accumulation of CLPX and mtDNA as well as inflammatory factors throughout tissues. T-lymphocytes in the spleen were activated. Thus, murine Clpp deletion represents a faithful Perrault model. The disease mechanism probably involves deficient clearance of mitochondrial components and inflammatory tissue destruction.
Collapse
|
27
|
Weis BL, Schleiff E, Zerges W. Protein targeting to subcellular organelles via MRNA localization. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1833:260-73. [PMID: 23457718 DOI: 10.1016/j.bbamcr.2012.04.004] [Citation(s) in RCA: 90] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Cells have complex membranous organelles for the compartmentalization and the regulation of most intracellular processes. Organelle biogenesis and maintenance requires newly synthesized proteins, each of which needs to go from the ribosome translating its mRNA to the correct membrane for insertion or transclocation to an a organellar subcompartment. Decades of research have revealed how proteins are targeted to the correct organelle and translocated across one or more organelle membranes ro the compartment where they function. The paradigm examples involve interactions between a peptide sequence in the protein, localization factors, and various membrane embedded translocation machineries. Membrane translocation is either cotranslational or posttranslational depending on the protein and target organelle. Meanwhile research in embryos, neurons and yeast revealed an alternative targeting mechanism in which the mRNA is localized and only then translated to synthesize the protein in the correct location. In these cases, the targeting information is coded by the cis-acting sequences in the mRNA ("Zipcodes") that interact with localization factors and, in many cases, are transported by the molecular motors on the cytoskeletal filaments. Recently, evidence has been found for this "mRNA based" mechanism in organelle protein targeting to endoplasmic reticulum, mitochondria, and the photosynthetic membranes within chloroplasts. Here we review known and potential roles of mRNA localization in protein targeting to and within organelles. This article is part of a Special Issue entitled: Protein Import and Quality Control in Mitochondria and Plastids.
Collapse
Affiliation(s)
- Benjamin L Weis
- Goether University, Cluster of Excellence Macromolecular Complexes, Institute for Molecular Biosciences, Max-von-Laue Str. 9, D-60438 Frankfort, Germany
| | | | | |
Collapse
|
28
|
Burak E, Yogev O, Sheffer S, Schueler-Furman O, Pines O. Evolving dual targeting of a prokaryotic protein in yeast. Mol Biol Evol 2013; 30:1563-73. [PMID: 23462316 DOI: 10.1093/molbev/mst039] [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] [Indexed: 11/14/2022] Open
Abstract
Dual targeting is an important and abundant phenomenon. Indeed, we estimate that more than a third of the yeast mitochondrial proteome is dual localized. The enzyme fumarase is a highly conserved protein in all organisms with respect to its sequence, structure, and enzymatic activity. In eukaryotes, it is dual localized to the cytosol and mitochondria. In Saccharomyces cerevisiae, the dual localization of fumarase is achieved by the reverse translocation mechanism; all fumarase molecules harbor a mitochondrial targeting sequence (MTS), are targeted to mitochondria, begin their translocation, and are processed by mitochondrial processing peptidase in the matrix. A subset of these processed fumarase molecules in transit is then fully imported into the matrix, whereas the majority moves back into the cytosol by reverse translocation. The proposed driving force for fumarase distribution is protein folding during import. Here, we asked how reverse translocation could have evolved on a prokaryotic protein that had already acquired expression from the nuclear genome and a targeting sequence. To address this question, we used, as a model, the Escherichia coli FumC Class II fumarase, which is homologous to eukaryotic fumarases (∼58% identity and ∼74% similarity to the yeast Fum1). Starting with an exclusively mitochondrial targeted FumC (attached to a strong MTS), we show that two randomly acquired mutations within the prokaryotic FumC sequence are sufficient to cause substantial dual targeting by reverse translocation. In fact, the unmutated MTS-FumC also has some ability to be dual targeted but only at low temperatures. Our results suggest that in this case, evolution of dual targeting by reverse translocation is based on naturally occurring and fortuitously conserved features of fumarase folding.
Collapse
Affiliation(s)
- Efrat Burak
- Department of Microbiology Molecular Genetics, IMRIC, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
| | | | | | | | | |
Collapse
|
29
|
Ishii H, Kunihiro S, Tanaka M, Hatano K, Nishikata T. Cytosolic subunits of ATP synthase are localized to the cortical endoplasmic reticulum-rich domain of the ascidian egg myoplasm. Dev Growth Differ 2013; 54:753-66. [PMID: 23067137 DOI: 10.1111/dgd.12003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Previously, we revealed that p58, one of the ascidian maternal factors, is identical to the alpha-subunit of F1-ATP synthase (ATPα), a protein complex of the inner mitochondrial membrane. In the current study, we used immunological probes for ascidian mitochondria components to show that the ascidian ATPα is ectopically localized to the cytosol. Virtually all mitochondrial components were localized to the mitochondria-rich myoplasm. However, in detail, ATP synthase subunits and the matrix proteins showed different localization patterns. At least at the crescent stage, transmission electron microscopy (TEM) distinguished the mitochondria-less, endoplasmic reticulum (ER)-rich cortical region and the mitochondria-rich internal region. ATPα was enriched in the cortical region and MnSOD was limited to the internal region. Using subcellular fractionation, although all of the mitochondria components were highly enriched in the mitochondria-enriched fraction, a considerable amount of ATPα and F1-ATP synthase beta-subunit (ATPβ) were recovered in the insoluble cytoplasmic fraction. Even under these conditions, F1-ATP synthase gamma-subunit (ATPγ) and F0-ATP synthase subunit b (ATPb) were not recovered in the insoluble cytoplasmic fraction. This result strongly supports the exomitochondrial localization of both ATPα and ATPβ. In addition, the detergent extraction of eggs supports the idea that these cytosolic ATP synthase subunits are associated with the egg cytoskeleton. These results suggest that the subunits of ATP synthase might play dual roles at different subcellular compartments during early development.
Collapse
Affiliation(s)
- Hirokazu Ishii
- Frontiers of Innovative Research in Science and Technology (FIRST), Konan University, Kobe, Hyogo, 650-0047, Japan.
| | | | | | | | | |
Collapse
|
30
|
Mah W, Deme JC, Watkins D, Fung S, Janer A, Shoubridge EA, Rosenblatt DS, Coulton JW. Subcellular location of MMACHC and MMADHC, two human proteins central to intracellular vitamin B(12) metabolism. Mol Genet Metab 2013; 108:112-8. [PMID: 23270877 DOI: 10.1016/j.ymgme.2012.11.284] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2012] [Revised: 11/29/2012] [Accepted: 11/29/2012] [Indexed: 11/22/2022]
Abstract
MMACHC and MMADHC are the genes responsible for cblC and cblD defects of vitamin B(12) metabolism, respectively. Patients with cblC and cblD defects present with various combinations of methylmalonic aciduria (MMA) and homocystinuria (HC). Those with cblC mutations have both MMA and HC whereas cblD patients can present with one of three distinct biochemical phenotypes: isolated MMA, isolated HC, or combined MMA and HC. Based on the subcellular localization of these enzymatic pathways it is thought that MMACHC functions in the cytoplasm while MMADHC functions downstream of MMACHC in both the cytoplasm and the mitochondrion. In this study we determined the subcellular location of MMACHC and MMADHC by immunofluorescence and subcellular fractionation. We show that MMACHC is cytoplasmic while MMADHC is both mitochondrial and cytoplasmic, consistent with the proposal that MMADHC acts as a branch point for vitamin B(12) delivery to the cytoplasm and mitochondria. The factors that determine the distribution of MMADHC between the cytoplasm and mitochondria remain unknown. Functional complementation experiments showed that retroviral expression of the GFP tagged constructs rescued all biochemical defects in cblC and cblD fibroblasts except propionate incorporation in cblD-MMA cells, suggesting that the endogenous mutant protein interferes with the function of the transduced wild type construct.
Collapse
Affiliation(s)
- Wayne Mah
- Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada
| | | | | | | | | | | | | | | |
Collapse
|
31
|
Fargue S, Lewin J, Rumsby G, Danpure CJ. Four of the most common mutations in primary hyperoxaluria type 1 unmask the cryptic mitochondrial targeting sequence of alanine:glyoxylate aminotransferase encoded by the polymorphic minor allele. J Biol Chem 2012; 288:2475-84. [PMID: 23229545 DOI: 10.1074/jbc.m112.432617] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The gene encoding the liver-specific peroxisomal enzyme alanine:glyoxylate aminotransferase (AGT, EC. 2.6.1.44) exists as two common polymorphic variants termed the "major" and "minor" alleles. The P11L amino acid replacement encoded by the minor allele creates a hidden N-terminal mitochondrial targeting sequence, the unmasking of which occurs in the hereditary calcium oxalate kidney stone disease primary hyperoxaluria type 1 (PH1). This unmasking is due to the additional presence of a common disease-specific G170R mutation, which is encoded by about one third of PH1 alleles. The P11L and G170R replacements interact synergistically to reroute AGT to the mitochondria where it cannot fulfill its metabolic role (i.e. glyoxylate detoxification) effectively. In the present study, we have reinvestigated the consequences of the interaction between P11L and G170R in stably transformed CHO cells and have studied for the first time whether a similar synergism exists between P11L and three other mutations that segregate with the minor allele (i.e. I244T, F152I, and G41R). Our investigations show that the latter three mutants are all able to unmask the cryptic P11L-generated mitochondrial targeting sequence and, as a result, all are mistargeted to the mitochondria. However, whereas the G170R, I244T, and F152I mutants are able to form dimers and are catalytically active, the G41R mutant aggregates and is inactive. These studies open up the possibility that all PH1 mutations, which segregate with the minor allele, might also lead to the peroxisome-to-mitochondrion mistargeting of AGT, a suggestion that has important implications for the development of treatment strategies for PH1.
Collapse
Affiliation(s)
- Sonia Fargue
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, United Kingdom
| | | | | | | |
Collapse
|
32
|
Becker D, Richter J, Tocilescu MA, Przedborski S, Voos W. Pink1 kinase and its membrane potential (Deltaψ)-dependent cleavage product both localize to outer mitochondrial membrane by unique targeting mode. J Biol Chem 2012; 287:22969-87. [PMID: 22547060 DOI: 10.1074/jbc.m112.365700] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The Parkinson disease-associated kinase Pink1 is targeted to mitochondria where it is thought to regulate mitochondrial quality control by promoting the selective autophagic removal of dysfunctional mitochondria. Nevertheless, the targeting mode of Pink1 and its submitochondrial localization are still not conclusively resolved. The aim of this study was to dissect the mitochondrial import pathway of Pink1 by use of a highly sensitive in vitro assay. Mutational analysis of the Pink1 sequence revealed that its N terminus acts as a genuine matrix localization sequence that mediates the initial membrane potential (Δψ)-dependent targeting of the Pink1 precursor to the inner mitochondrial membrane, but it is dispensable for Pink1 import or processing. A hydrophobic segment downstream of the signal sequence impeded complete translocation of Pink1 across the mitochondrial inner membrane. Additionally, the C-terminal end of the protein promoted the retention of Pink1 at the outer membrane. Thus, multiple targeting signals featured by the Pink1 sequence result in the final localization of both the full-length protein and its major Δψ-dependent cleavage product to the cytosolic face of the outer mitochondrial membrane. Full-length Pink1 and deletion constructs resembling the natural Pink1 processing product were found to assemble into membrane potential-sensitive high molecular weight protein complexes at the mitochondrial surface and displayed similar cytoprotective effects when expressed in vivo, indicating that both species are functionally relevant.
Collapse
Affiliation(s)
- Dorothea Becker
- Institut für Biochemie und Molekularbiologie (IBMB), Universität Bonn, Nussallee 11, 53115 Bonn, Germany
| | | | | | | | | |
Collapse
|
33
|
Papa S, Martino PL, Capitanio G, Gaballo A, De Rasmo D, Signorile A, Petruzzella V. The oxidative phosphorylation system in mammalian mitochondria. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 942:3-37. [PMID: 22399416 DOI: 10.1007/978-94-007-2869-1_1] [Citation(s) in RCA: 169] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The chapter provides a review of the state of art of the oxidative phosphorylation system in mammalian mitochondria. The sections of the paper deal with: (i) the respiratory chain as a whole: redox centers of the chain and protonic coupling in oxidative phosphorylation (ii) atomic structure and functional mechanism of protonmotive complexes I, III, IV and V of the oxidative phosphorylation system (iii) biogenesis of oxidative phosphorylation complexes: mitochondrial import of nuclear encoded subunits, assembly of oxidative phosphorylation complexes, transcriptional factors controlling biogenesis of the complexes. This advanced knowledge of the structure, functional mechanism and biogenesis of the oxidative phosphorylation system provides a background to understand the pathological impact of genetic and acquired dysfunctions of mitochondrial oxidative phosphorylation.
Collapse
Affiliation(s)
- Sergio Papa
- Department of Basic Medical Sciences, University of Bari, Bari, Italy.
| | | | | | | | | | | | | |
Collapse
|
34
|
Klein JM, Schwarz G. Cofactor-dependent maturation of mammalian sulfite oxidase links two mitochondrial import pathways. J Cell Sci 2012; 125:4876-85. [DOI: 10.1242/jcs.110114] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Sulfite oxidase (SO) catalyzes the metabolic detoxification of sulfite to sulfate within the intermembrane space of mitochondria. The enzyme follows a complex maturation pathway, including mitochondrial transport and processing, integration of two prosthetic groups, the molybdenum-cofactor (Moco) and heme, as well as homodimerization. Here, we have identified the sequential and cofactor-dependent maturation steps of SO. The N-terminal bipartite targeting signal of SO was required but not sufficient for mitochondrial localization. In absence of Moco, most of SO, although processed by the inner membrane peptidase of mitochondria, was found in the cytosol. Moco binding was required to induce mitochondrial trapping and retention, thus ensuring unidirectional translocation of SO. In absence of the N-terminal targeting sequence, SO assembled in the cytosol, suggesting an important function for the leader sequence in preventing premature cofactor binding. In vivo, heme binding and dimerization were prohibited in absence of Moco and only occurred after Moco integration. In conclusion, the identified molecular hierarchy of SO maturation represents a novel link between the canonical presequence pathway and folding-trap mechanisms of mitochondrial import.
Collapse
|
35
|
Abstract
The enzyme fumarase is a conserved protein in all organisms with regard to its sequence, structure and function. This enzyme participates in the tricarboxylic acid cycle in mitochondria which is essential for cellular respiration in eukaryotes. However, a common theme conserved from yeast to humans is the existence of a cytosolic form of fumarase; hence this protein is dual localized. We have coined identical (or nearly identical) proteins situated in different subcellular locations 'echoforms' or 'echoproteins'. Fumarase was the first example of a dual localized protein whose mechanism of distribution was found to be based on a single translation product. Consequently, fumarase has become a paradigm for three unique eukaryotic cellular phenomena related to protein dual localization: (a) distribution between mitochondria and the cytoplasm involves reverse translocation; (b) targeting to mitochondria involves translation coupled import; and (c) there are two echoforms possessing distinct functions in the respective subcellular compartments. Here we describe and discuss these fumarase related phenomena and in addition point out approaches for studying dual function of distributed proteins, in particular compartment-specific depletion. In the case of fumarase, the cytoplasmic function was only recently discovered; the enzyme was found to participate in the cellular response to DNA double strand breaks. Strikingly, upon DNA damage the protein is transported from the cytosol to the nucleus, where by virtue of its enzymatic activity it participates in the DNA damage response.
Collapse
Affiliation(s)
- Ohad Yogev
- Department of Microbiology and Molecular Genetics, IMRIC, Faculty of Medicine, Hebrew University, Jerusalem, Israel
| | | | | |
Collapse
|
36
|
Zhdanov AV, Favre C, O'Flaherty L, Adam J, O'Connor R, Pollard PJ, Papkovsky DB. Comparative bioenergetic assessment of transformed cells using a cell energy budget platform. Integr Biol (Camb) 2011; 3:1135-42. [PMID: 22005712 DOI: 10.1039/c1ib00050k] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The aberrant expression and functional activity of proteins involved in ATP production pathways may cause a crisis in energy generation for cells and compromise their survival under stressful conditions such as excitation, starvation, pharmacological treatment or disease states. Under resting conditions such defects are often compensated for, and therefore masked by, alternative pathways which have significant spare capacity. Here we present a multiplexed 'cell energy budget' platform which facilitates metabolic assessment and cross-comparison of different cells and the identification of genes directly or indirectly involved in ATP production. Long-decay emitting O(2) and pH sensitive probes and time-resolved fluorometry are used to measure changes in cellular O(2) consumption, glycolytic and total extracellular acidification (ECA), along with the measurement of total ATP and protein content in multiple samples. To assess the extent of spare capacity in the main energy pathways, the cells are also analysed following double-treatment with carbonyl cyanide p-(trifluoromethoxy)phenylhydrazone and oligomycin. The four-parametric platform operating in a high throughput format has been validated with two panels of transformed cells: mouse embryonic fibroblasts (MEFs) lacking the Krebs cycle enzyme fumarate hydratase (Fh1) and HeLa cells with reduced expression of pyrimidine nucleotide carrier 1. In both cases, a marked reduction in both respiration and spare respiratory capacity was observed, accompanied by a compensatory activation of glycolysis and consequent maintenance of total ATP levels. At the same time, in Fh1-deficient MEFs the contribution of non-glycolytic pathways to the ECA did not change.
Collapse
Affiliation(s)
- A V Zhdanov
- Biochemistry Department, University College Cork, Cavanagh Pharmacy Building, College Road, Cork, Ireland
| | | | | | | | | | | | | |
Collapse
|
37
|
Rettig J, Wang Y, Schneider A, Ochsenreiter T. Dual targeting of isoleucyl-tRNA synthetase in Trypanosoma brucei is mediated through alternative trans-splicing. Nucleic Acids Res 2011; 40:1299-306. [PMID: 21976735 PMCID: PMC3273800 DOI: 10.1093/nar/gkr794] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Aminoacyl-tRNA synthetases catalyze the aminoacylation of tRNAs with their cognate amino acids. They are an essential part of each translation system and in eukaryotes are therefore found in both the cytosol and mitochondria. Thus, eukaryotes either have two distinct genes encoding the cytosolic and mitochondrial isoforms of each of these enzymes or a single gene encoding dually localized products. Trypanosomes require trans-splicing of a cap containing leader sequence onto the 5′-untranslated region of every mRNA. Recently we speculated that alternative trans-splicing could lead to the expression of proteins having amino-termini of different lengths that derive from the same gene. We now demonstrate that alternative trans-splicing, creating a long and a short spliced variant, is the mechanism for dual localization of trypanosomal isoleucyl-tRNA synthetase (IleRS). The protein product of the longer spliced variant possesses an amino-terminal presequence and is found exclusively in mitochondria. In contrast, the shorter spliced variant is translated to a cytosol-specific isoform lacking the presequence. Furthermore, we show that RNA stability is one mechanism determining the differential abundance of the two spliced isoforms.
Collapse
Affiliation(s)
- Jochen Rettig
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, 3012 Bern, Switzerland
| | | | | | | |
Collapse
|
38
|
Ben-Menachem R, Regev-Rudzki N, Pines O. The aconitase C-terminal domain is an independent dual targeting element. J Mol Biol 2011; 409:113-23. [PMID: 21440554 DOI: 10.1016/j.jmb.2011.03.045] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2011] [Revised: 03/17/2011] [Accepted: 03/20/2011] [Indexed: 11/26/2022]
Abstract
The tricarboxylic acid cycle enzyme aconitase in yeast is a single translation product, which is dual targeted and distributed between the mitochondria and the cytosol by a unique mechanism involving reverse translocation. There is limited understanding regarding the precise mechanism of reverse translocation across the mitochondrial membranes. Here, we examined the contribution of the mature part of aconitase to its dual targeting. We created a set of aconitase mutants harboring two kinds of alterations: (1) point mutations or very small deletions in conserved sites and (2) systematic large deletions. These mutants were screened for their localization by a α-complementation assay, which revealed that the aconitase fourth domain that is at the C-terminus (amino acids 517-778) is required for aconitase distribution. Moreover, fusion of this C-terminal domain to mitochondria-targeted passenger proteins such as dihydrofolate reductase and orotidine-5'-phosphate decarboxylase, conferred dual localization on them. These results indicate that the aconitase C-terminal domain is both necessary and sufficient for dual targeting, thereby functioning as an "independent signal". In addition, the same C-terminal domain was shown to be necessary for aconitase efficient posttranslational import into mitochondria.
Collapse
Affiliation(s)
- Reut Ben-Menachem
- Department of Microbiology and Molecular Genetics, Institute of Medical Research Israel-Canada, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 91120, Israel
| | | | | |
Collapse
|
39
|
Ding Y, Li S, Dou C, Yu Y, Huang H. Production of Fumaric Acid by Rhizopus oryzae: Role of Carbon–Nitrogen Ratio. Appl Biochem Biotechnol 2011; 164:1461-7. [DOI: 10.1007/s12010-011-9226-y] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2010] [Accepted: 03/01/2011] [Indexed: 10/18/2022]
|
40
|
Kim G, Cole NB, Lim JC, Zhao H, Levine RL. Dual sites of protein initiation control the localization and myristoylation of methionine sulfoxide reductase A. J Biol Chem 2010; 285:18085-94. [PMID: 20368336 PMCID: PMC2878569 DOI: 10.1074/jbc.m110.119701] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Methionine sulfoxide reductase A is an essential enzyme in the antioxidant system, which scavenges reactive oxygen species through cyclic oxidation and reduction of methionine and methionine sulfoxide. In mammals, one gene encodes two forms of the reductase, one targeted to the cytosol and the other to mitochondria. The cytosolic form displays faster mobility than the mitochondrial form, suggesting a lower molecular weight for the former. The apparent size difference and targeting to two cellular compartments had been proposed to result from differential splicing of mRNA. We now show that differential targeting is effected by use of two initiation sites, one of which includes a mitochondrial targeting sequence, whereas the other does not. We also demonstrate that the mass of the cytosolic form is not less than that of the mitochondrial form; the faster mobility of cytosolic form is due to its myristoylation. Lipidation of methionine sulfoxide reductase A occurs in the mouse, in transfected tissue culture cells, and even in a cell-free protein synthesis system. The physiologic role of myristoylation of MsrA remains to be elucidated.
Collapse
Affiliation(s)
- Geumsoo Kim
- Laboratory of Biochemistry, NHLBI, National Institutes of Health, Bethesda, Maryland 20892, USA
| | | | | | | | | |
Collapse
|
41
|
Endo T, Yamano K. Transport of proteins across or into the mitochondrial outer membrane. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2010; 1803:706-14. [DOI: 10.1016/j.bbamcr.2009.11.007] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2009] [Revised: 11/11/2009] [Accepted: 11/17/2009] [Indexed: 11/30/2022]
|
42
|
Mitochondrial translation and beyond: processes implicated in combined oxidative phosphorylation deficiencies. J Biomed Biotechnol 2010; 2010:737385. [PMID: 20396601 PMCID: PMC2854570 DOI: 10.1155/2010/737385] [Citation(s) in RCA: 142] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2009] [Accepted: 01/29/2010] [Indexed: 12/22/2022] Open
Abstract
Mitochondrial disorders are a heterogeneous group of often multisystemic and early fatal diseases, which are amongst the most common inherited human diseases. These disorders are caused by defects in the oxidative phosphorylation (OXPHOS) system, which comprises five multisubunit enzyme complexes encoded by both the nuclear and the mitochondrial genomes. Due to the multitude of proteins and intricacy of the processes required for a properly functioning OXPHOS system, identifying the genetic defect that underlies an OXPHOS deficiency is not an easy task, especially in the case of combined OXPHOS defects. In the present communication we give an extensive overview of the proteins and processes (in)directly involved in mitochondrial translation and the biogenesis of the OXPHOS system and their roles in combined OXPHOS deficiencies. This knowledge is important for further research into the genetic causes, with the ultimate goal to effectively prevent and cure these complex and often devastating disorders.
Collapse
|
43
|
Yogev O, Yogev O, Singer E, Shaulian E, Goldberg M, Fox TD, Pines O. Fumarase: a mitochondrial metabolic enzyme and a cytosolic/nuclear component of the DNA damage response. PLoS Biol 2010; 8:e1000328. [PMID: 20231875 PMCID: PMC2834712 DOI: 10.1371/journal.pbio.1000328] [Citation(s) in RCA: 163] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2009] [Accepted: 02/03/2010] [Indexed: 02/07/2023] Open
Abstract
Upon DNA damage, a cytosolic form of the mitochondrial enzyme fumarase moves into the nucleus where, by virtue of its enzymatic activity, it participates in the cell's response to DNA damage. This potentially explains its known role as a tumor suppressor. In eukaryotes, fumarase (FH in human) is a well-known tricarboxylic-acid-cycle enzyme in the mitochondrial matrix. However, conserved from yeast to humans is a cytosolic isoenzyme of fumarase whose function in this compartment remains obscure. A few years ago, FH was surprisingly shown to underlie a tumor susceptibility syndrome, Hereditary Leiomyomatosis and Renal Cell Cancer (HLRCC). A biallelic inactivation of FH has been detected in almost all HLRCC tumors, and therefore FH was suggested to function as a tumor suppressor. Recently it was suggested that FH inhibition leads to elevated intracellular fumarate, which in turn acts as a competitive inhibitor of HPH (HIF prolyl hydroxylase), thereby causing stabilization of HIF (Hypoxia-inducible factor) by preventing proteasomal degradation. The transcription factor HIF increases the expression of angiogenesis regulated genes, such as VEGF, which can lead to high microvessel density and tumorigenesis. Yet this mechanism does not fully explain the large cytosolic population of fumarase molecules. We constructed a yeast strain in which fumarase is localized exclusively to mitochondria. This led to the discovery that the yeast cytosolic fumarase plays a key role in the protection of cells from DNA damage, particularly from DNA double-strand breaks. We show that the cytosolic fumarase is a member of the DNA damage response that is recruited from the cytosol to the nucleus upon DNA damage induction. This function of fumarase depends on its enzymatic activity, and its absence in cells can be complemented by high concentrations of fumaric acid. Our findings suggest that fumarase and fumaric acid are critical elements of the DNA damage response, which underlies the tumor suppressor role of fumarase in human cells and which is most probably HIF independent. This study shows an exciting crosstalk between primary metabolism and the DNA damage response, thereby providing a scenario for metabolic control of tumor propagation. Fumarate hydratase (FH; also known as fumarase) is an enzyme found in both the cytoplasm and mitochondria of all eukaryotes. In mitochondria, FH is involved in generating energy for the cell through a metabolic pathway called the Krebs cycle. Its role in the cytoplasm, however, is unclear. FH can function as a tumor suppressor: its absence is linked to the formation of human kidney tumors in a syndrome termed HLRCC. We show here that the cytoplasmic version of FH has an unexpected role in repairing DNA double-strand breaks in the nucleus. This role involves the movement of FH from the cytoplasm into the nucleus and depends on its enzymatic activity. Strikingly, when FH is absent from cells, its function in DNA repair can be substituted by high concentrations of one of the enzyme's products, fumaric acid. Our findings imply that FH deficiency leads to cancer because there is not enough fumaric acid in the nucleus to stimulate repair of DNA double-strand breaks; the persistence of these breaks is believed to provoke cancer. The study thus makes a surprising connection between primary metabolism and the cell's response to DNA damage.
Collapse
Affiliation(s)
- Ohad Yogev
- Department of Microbiology and Molecular Genetics, IMRIC, Faculty of Medicine, Hebrew University, Jerusalem, Israel
| | - Orli Yogev
- Department of Biochemistry and Molecular Biology, IMRIC, Faculty of Medicine, Hebrew University, Jerusalem, Israel
| | - Esti Singer
- Department of Microbiology and Molecular Genetics, IMRIC, Faculty of Medicine, Hebrew University, Jerusalem, Israel
| | - Eitan Shaulian
- Department of Biochemistry and Molecular Biology, IMRIC, Faculty of Medicine, Hebrew University, Jerusalem, Israel
| | - Michal Goldberg
- Department of Genetics, The Institute of Life Sciences, The Hebrew University, Jerusalem, Israel
| | - Thomas D. Fox
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York, United States of America
| | - Ophry Pines
- Department of Microbiology and Molecular Genetics, IMRIC, Faculty of Medicine, Hebrew University, Jerusalem, Israel
- * E-mail:
| |
Collapse
|
44
|
Matthews GD, Gur N, Koopman WJH, Pines O, Vardimon L. Weak mitochondrial targeting sequence determines tissue-specific subcellular localization of glutamine synthetase in liver and brain cells. J Cell Sci 2010; 123:351-9. [PMID: 20053634 DOI: 10.1242/jcs.060749] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Evolution of the uricotelic system for ammonia detoxification required a mechanism for tissue-specific subcellular localization of glutamine synthetase (GS). In uricotelic vertebrates, GS is mitochondrial in liver cells and cytoplasmic in brain. Because these species contain a single copy of the GS gene, it is not clear how tissue-specific subcellular localization is achieved. Here we show that in chicken, which utilizes the uricotelic system, the GS transcripts of liver and brain cells are identical and, consistently, there is no difference in the amino acid sequence of the protein. The N-terminus of GS, which constitutes a 'weak' mitochondrial targeting signal (MTS), is sufficient to direct a chimeric protein to the mitochondria in hepatocytes and to the cytoplasm in astrocytes. Considering that a weak MTS is dependent on a highly negative mitochondrial membrane potential (DeltaPsi) for import, we examined the magnitude of DeltaPsi in hepatocytes and astrocytes. Our results unexpectedly revealed that DeltaPsi in hepatocytes is considerably more negative than that of astrocytes and that converting the targeting signal into 'strong' MTS abolished the capability to confer tissue-specific subcellular localization. We suggest that evolutional selection of weak MTS provided a tool for differential targeting of an identical protein by taking advantage of tissue-specific differences in DeltaPsi.
Collapse
Affiliation(s)
- Gideon D Matthews
- Department of Biochemistry, George S. Wise Faculty of Life Sciences, Tel Aviv University, 69978 Tel Aviv, Israel
| | | | | | | | | |
Collapse
|
45
|
Outer mitochondrial membrane localization of apoptosis-inducing factor: mechanistic implications for release. ASN Neuro 2009; 1:AN20090046. [PMID: 19863494 PMCID: PMC2784601 DOI: 10.1042/an20090046] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Poly(ADP-ribose) polymerase-1-dependent cell death (known as parthanatos) plays a pivotal role in many clinically important events including ischaemia/reperfusion injury and glutamate excitotoxicity. A recent study by us has shown that uncleaved AIF (apoptosis-inducing factor), but not calpain-hydrolysed truncated-AIF, was rapidly released from the mitochondria during parthanatos, implicating a second pool of AIF that might be present in brain mitochondria contributing to the rapid release. In the present study, a novel AIF pool is revealed in brain mitochondria by multiple biochemical analyses. Approx. 30% of AIF loosely associates with the outer mitochondrial membrane on the cytosolic side, in addition to its main localization in the mitochondrial intermembrane space attached to the inner membrane. Immunogold electron microscopic analysis of mouse brain further supports AIF association with the outer, as well as the inner, mitochondrial membrane in vivo. In line with these observations, approx. 20% of uncleaved AIF rapidly translocates to the nucleus and functionally causes neuronal death upon NMDA (N-methyl-d-aspartate) treatment. In the present study we show for the first time a second pool of AIF in brain mitochondria and demonstrate that this pool does not require cleavage and that it contributes to the rapid release of AIF. Moreover, these results suggest that this outer mitochondrial pool of AIF is sufficient to cause cell death during parthanatos. Interfering with the release of this outer mitochondrial pool of AIF during cell injury paradigms that use parthanatos hold particular promise for novel therapies to treat neurological disorders.
Collapse
|
46
|
Naamati A, Regev-Rudzki N, Galperin S, Lill R, Pines O. Dual targeting of Nfs1 and discovery of its novel processing enzyme, Icp55. J Biol Chem 2009; 284:30200-8. [PMID: 19720832 DOI: 10.1074/jbc.m109.034694] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In eukaryotes, each subcellular compartment harbors a specific group of proteins that must accomplish specific tasks. Nfs1 is a highly conserved mitochondrial cysteine desulfurase that participates in iron-sulfur cluster assembly as a sulfur donor. Previous genetic studies, in Saccharomyces cerevisiae, have suggested that this protein distributes between the mitochondria and the nucleus with biochemically undetectable amounts in the nucleus (termed "eclipsed distribution"). Here, we provide direct evidence for Nfs1 nuclear localization (in addition to mitochondria) using both alpha-complementation and subcellular fractionation. We also demonstrate that mitochondrial and nuclear Nfs1 are derived from a single translation product. Our data suggest that the Nfs1 distribution mechanism involves at least partial entry of the Nfs1 precursor into mitochondria, and then retrieval of a minor subpopulation (probably by reverse translocation) into the cytosol and then the nucleus. To further elucidate the mechanism of Nfs1 distribution we determined the N-terminal mitochondrial sequence of Nfs1 by Edman degradation. This led to the discovery of a novel mitochondrial processing enzyme, Icp55. This enzyme removes three amino acids from the N terminus of Nfs1 after cleavage by mitochondrial processing peptidase. Intriguingly, Icp55 protease (like its substrate Nfs1) appears to be dual distributed between the nucleus and mitochondria.
Collapse
Affiliation(s)
- Adi Naamati
- Department of Microbiology and Molecular Genetics, IMRIC, Faculty of Medicine, Hebrew University, Jerusalem 91120, Israel
| | | | | | | | | |
Collapse
|
47
|
Frechin M, Senger B, Brayé M, Kern D, Martin RP, Becker HD. Yeast mitochondrial Gln-tRNA(Gln) is generated by a GatFAB-mediated transamidation pathway involving Arc1p-controlled subcellular sorting of cytosolic GluRS. Genes Dev 2009; 23:1119-30. [PMID: 19417106 DOI: 10.1101/gad.518109] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
It is impossible to predict which pathway, direct glutaminylation of tRNA(Gln) or tRNA-dependent transamidation of glutamyl-tRNA(Gln), generates mitochondrial glutaminyl-tRNA(Gln) for protein synthesis in a given species. The report that yeast mitochondria import both cytosolic glutaminyl-tRNA synthetase and tRNA(Gln) has challenged the widespread use of the transamidation pathway in organelles. Here we demonstrate that yeast mitochondrial glutaminyl-tRNA(Gln) is in fact generated by a transamidation pathway involving a novel type of trimeric tRNA-dependent amidotransferase (AdT). More surprising is the fact that cytosolic glutamyl-tRNA synthetase ((c)ERS) is imported into mitochondria, where it constitutes the mitochondrial nondiscriminating ERS that generates the mitochondrial mischarged glutamyl-tRNA(Gln) substrate for the AdT. We show that dual localization of (c)ERS is controlled by binding to Arc1p, a tRNA nuclear export cofactor that behaves as a cytosolic anchoring platform for (c)ERS. Expression of Arc1p is down-regulated when yeast cells are switched from fermentation to respiratory metabolism, thus allowing increased import of (c)ERS to satisfy a higher demand of mitochondrial glutaminyl-tRNA(Gln) for mitochondrial protein synthesis. This novel strategy that enables a single protein to be localized in both the cytosol and mitochondria provides a new paradigm for regulation of the dynamic subcellular distribution of proteins between membrane-separated compartments.
Collapse
Affiliation(s)
- Mathieu Frechin
- UPR 9002, Architecture et Réactivité de l'ARN, Université de Strasbourg, CNRS, Institut de Biologie Moléculaire et Cellulaire, Strasbourg, France
| | | | | | | | | | | |
Collapse
|
48
|
Anandatheerthavarada HK, Sepuri NBV, Avadhani NG. Mitochondrial targeting of cytochrome P450 proteins containing NH2-terminal chimeric signals involves an unusual TOM20/TOM22 bypass mechanism. J Biol Chem 2009; 284:17352-17363. [PMID: 19401463 DOI: 10.1074/jbc.m109.007492] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Previously we showed that xenobiotic inducible cytochrome P450 (CYP) proteins are bimodally targeted to the endoplasmic reticulum and mitochondria. In this study, we investigated the mechanism of delivery of chimeric signal containing CYP proteins to the peripheral and channel-forming mitochondrial outer membrane translocases (TOMs). CYP+33/1A1 and CYP2B1 did not require peripheral TOM70, TOM20, or TOM22 for translocation through the channel-forming TOM40 protein. In contrast, CYP+5/1A1 and CYP2E1 were able to bypass TOM20 and TOM22 but required TOM70. CYP27, which contains a canonical cleavable mitochondrial signal, required all of the peripheral TOMs for its mitochondrial translocation. We investigated the underlying mechanisms of bypass of peripheral TOMs by CYPs with chimeric signals. The results suggested that interaction of CYPs with Hsp70, a cytosolic chaperone involved in the mitochondrial import, alone was sufficient for the recognition of chimeric signals by peripheral TOMs. However, sequential interaction of chimeric signal containing CYPs with Hsp70 and Hsp90 resulted in the bypass of peripheral TOMs, whereas CYP27A1 interacted only with Hsp70 and was not able to bypass peripheral TOMs. Our results also show that delivery of a chimeric signal containing client protein by Hsp90 required the cytosol-exposed NH(2)-terminal 143 amino acids of TOM40. TOM40 devoid of this domain was unable to import CYP proteins. These results suggest that compared with the unimodal mitochondrial targeting signals, the chimeric mitochondrial targeting signals are highly evolved and dynamic in nature.
Collapse
Affiliation(s)
- Hindupur K Anandatheerthavarada
- From the Department of Animal Biology and the Mari Lowe Center for Comparative Oncology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Naresh Babu V Sepuri
- From the Department of Animal Biology and the Mari Lowe Center for Comparative Oncology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Narayan G Avadhani
- From the Department of Animal Biology and the Mari Lowe Center for Comparative Oncology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104.
| |
Collapse
|
49
|
Regev-Rudzki N, Battat E, Goldberg I, Pines O. Dual localization of fumarase is dependent on the integrity of the glyoxylate shunt. Mol Microbiol 2009; 72:297-306. [DOI: 10.1111/j.1365-2958.2009.06659.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
50
|
Ahmed AU, Fisher PR. Import of nuclear-encoded mitochondrial proteins: a cotranslational perspective. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2009; 273:49-68. [PMID: 19215902 DOI: 10.1016/s1937-6448(08)01802-9] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
A growing amount of evidence suggests that the cytosolic translation of nuclear-encoded mitochondrial proteins and their subsequent import into mitochondria are tightly coupled in a process termed cotranslational import. In addition to the original posttranslational view of mitochondrial protein import, early literature also provides both in vitro and in vivo experimental evidence supporting the simultaneous existence of a cotranslational protein-import mechanism in mitochondria. Recent investigations have started to reveal the cotranslational import mechanism which is initiated by transporting either a translation complex or a translationally competent mRNA encoding a mitochondrial protein to the mitochondrial surface. The intracellular localization of mRNA to the mitochondrial surface has emerged as the latest addition to our understanding of mitochondrial biogenesis. It is mediated by targeting elements within the mRNA molecule in association with potential mRNA-binding proteins.
Collapse
Affiliation(s)
- Afsar U Ahmed
- Department of Microbiology, La Trobe University, Victoria, Australia
| | | |
Collapse
|