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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.
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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
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2
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Dancis A, Pandey AK, Pain D. Mitochondria function in cytoplasmic FeS protein biogenesis. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2024; 1871:119733. [PMID: 38641180 DOI: 10.1016/j.bbamcr.2024.119733] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Revised: 03/18/2024] [Accepted: 04/12/2024] [Indexed: 04/21/2024]
Abstract
Iron‑sulfur (FeS) clusters are cofactors of numerous proteins involved in essential cellular functions including respiration, protein translation, DNA synthesis and repair, ribosome maturation, anti-viral responses, and isopropylmalate isomerase activity. Novel FeS proteins are still being discovered due to the widespread use of cryogenic electron microscopy (cryo-EM) and elegant genetic screens targeted at protein discovery. A complex sequence of biochemical reactions mediated by a conserved machinery controls biosynthesis of FeS clusters. In eukaryotes, a remarkable epistasis has been observed: the mitochondrial machinery, termed ISC (Iron-Sulfur Cluster), lies upstream of the cytoplasmic machinery, termed CIA (Cytoplasmic Iron‑sulfur protein Assembly). The basis for this arrangement is the production of a hitherto uncharacterized intermediate, termed X-S or (Fe-S)int, produced in mitochondria by the ISC machinery, exported by the mitochondrial ABC transporter Atm1 (ABCB7 in humans), and then utilized by the CIA machinery for the cytoplasmic/nuclear FeS cluster assembly. Genetic and biochemical findings supporting this sequence of events are herein presented. New structural views of the Atm1 transport phases are reviewed. The key compartmental roles of glutathione in cellular FeS cluster biogenesis are highlighted. Finally, data are presented showing that every one of the ten core components of the mitochondrial ISC machinery and Atm1, when mutated or depleted, displays similar phenotypes: mitochondrial and cytoplasmic FeS clusters are both rendered deficient, consistent with the epistasis noted above.
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Affiliation(s)
- Andrew Dancis
- Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School, Rutgers University, Newark, NJ 07103, USA.
| | - Ashutosh K Pandey
- Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School, Rutgers University, Newark, NJ 07103, USA
| | - Debkumar Pain
- Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School, Rutgers University, Newark, NJ 07103, USA
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3
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Yamano K, Kinefuchi H, Kojima W. Mitochondrial quality control via organelle and protein degradation. J Biochem 2024; 175:487-494. [PMID: 38102729 DOI: 10.1093/jb/mvad106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Revised: 11/07/2023] [Accepted: 11/20/2023] [Indexed: 12/17/2023] Open
Abstract
Mitochondria are essential eukaryotic organelles that produce ATP as well as synthesize various macromolecules. They also participate in signalling pathways such as the innate immune response and apoptosis. These diverse functions are performed by >1,000 different mitochondrial proteins. Although mitochondria are continuously exposed to potentially damaging conditions such as reactive oxygen species, proteases/peptidases localized in different mitochondrial subcompartments, termed mitoproteases, maintain mitochondrial quality and integrity. In addition to processing incoming precursors and degrading damaged proteins, mitoproteases also regulate metabolic reactions, mitochondrial protein half-lives and gene transcription. Impaired mitoprotease function is associated with various pathologies. In this review, we highlight recent advances in our understanding of mitochondrial quality control regulated by autophagy, ubiquitin-proteasomes and mitoproteases.
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Affiliation(s)
- Koji Yamano
- Department of Biomolecular Pathogenesis, Medical Research Institute, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8510, Japan
| | - Hiroki Kinefuchi
- Department of Biomolecular Pathogenesis, Medical Research Institute, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8510, Japan
- Department of Biosciences, School of Science, Kitasato University, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa 252-0373, Japan
| | - Waka Kojima
- Department of Biomolecular Pathogenesis, Medical Research Institute, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8510, Japan
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4
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Torres NJ, Rizzo DN, Reinberg MA, Jobson ME, Totzke BC, Jackson JK, Yu W, Shaw LN. The identification of two M20B family peptidases required for full virulence in Staphylococcus aureus. Front Cell Infect Microbiol 2023; 13:1176769. [PMID: 37538308 PMCID: PMC10394242 DOI: 10.3389/fcimb.2023.1176769] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Accepted: 06/13/2023] [Indexed: 08/05/2023] Open
Abstract
We have previously demonstrated that deletion of an intracellular leucine aminopeptidase results in attenuated virulence of S. aureus. Herein we explore the role of 10 other aminopeptidases in S. aureus pathogenesis. Using a human blood survival assay we identified mutations in two enzymes from the M20B family (PepT1 and PepT2) as having markedly decreased survival compared to the parent. We further reveal that pepT1, pepT2 and pepT1/2 mutant strains are impaired in their ability to resist phagocytosis by, and engender survival within, human macrophages. Using a co-infection model of murine sepsis, we demonstrate impairment of dissemination and survival for both single mutants that is even more pronounced in the double mutant. We show that these enzymes are localized to the cytosol and membrane but are not necessary for peptide-based nutrition, a hallmark of cell-associated aminopeptidases. Furthermore, none of the survival defects appear to be the result of altered virulence factor production. An exploration of their regulation reveals that both are controlled by known regulators of the S. aureus virulence process, including Agr, Rot and/or SarA, and that this cascade may be mediated by FarR. Structural modeling of PepT1 reveals it bears all the hallmarks of a tripeptidase, whilst PepT2 differs significantly in its catalytic pocket, suggesting a broader substrate preference. In sum, we have identified two M20B aminopeptidases that are integral to S. aureus pathogenesis. The future identification of protein and/or peptide targets for these proteases will be critical to understanding their important virulence impacting functions.
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Affiliation(s)
| | | | | | | | | | | | | | - Lindsey N. Shaw
- Department of Molecular Biosciences, University of South Florida, Tampa, FL, United States
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5
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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.
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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.)
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Marinaccio J, Micheli E, Udroiu I, Di Nottia M, Carrozzo R, Baranzini N, Grimaldi A, Leone S, Moreno S, Muzzi M, Sgura A. TERT Extra-Telomeric Roles: Antioxidant Activity and Mitochondrial Protection. Int J Mol Sci 2023; 24:ijms24054450. [PMID: 36901881 PMCID: PMC10002448 DOI: 10.3390/ijms24054450] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Revised: 01/18/2023] [Accepted: 02/20/2023] [Indexed: 03/05/2023] Open
Abstract
Telomerase reverse transcriptase (TERT) is the catalytic subunit of telomerase holoenzyme, which adds telomeric DNA repeats on chromosome ends to counteract telomere shortening. In addition, there is evidence of TERT non-canonical functions, among which is an antioxidant role. In order to better investigate this role, we tested the response to X-rays and H2O2 treatment in hTERT-overexpressing human fibroblasts (HF-TERT). We observed in HF-TERT a reduced induction of reactive oxygen species and an increased expression of the proteins involved in the antioxidant defense. Therefore, we also tested a possible role of TERT inside mitochondria. We confirmed TERT mitochondrial localization, which increases after oxidative stress (OS) induced by H2O2 treatment. We next evaluated some mitochondrial markers. The basal mitochondria quantity appeared reduced in HF-TERT compared to normal fibroblasts and an additional reduction was observed after OS; nevertheless, the mitochondrial membrane potential and morphology were better conserved in HF-TERT. Our results suggest a protective function of TERT against OS, also preserving mitochondrial functionality.
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Affiliation(s)
| | - Emanuela Micheli
- Department of Science, University “ROMA TRE”, 00146 Rome, Italy
- Correspondence:
| | - Ion Udroiu
- Department of Science, University “ROMA TRE”, 00146 Rome, Italy
| | - Michela Di Nottia
- Unit of Muscular and Neurodegenerative Disorders, Laboratory of Molecular Medicine, Bambino Gesù Children’s Hospital IRCCS, 00146 Rome, Italy
| | - Rosalba Carrozzo
- Unit of Muscular and Neurodegenerative Disorders, Laboratory of Molecular Medicine, Bambino Gesù Children’s Hospital IRCCS, 00146 Rome, Italy
| | - Nicolò Baranzini
- Department of Biotechnology and Life Sciences, University of Insubria, 21100 Varese, Italy
| | - Annalisa Grimaldi
- Department of Biotechnology and Life Sciences, University of Insubria, 21100 Varese, Italy
| | - Stefano Leone
- Department of Anatomical, Histological, Forensic Medicine and Orthopedics Sciences, Sapienza University of Rome, 00161 Rome, Italy
| | - Sandra Moreno
- Department of Science, University “ROMA TRE”, 00146 Rome, Italy
- IRCCS Santa Lucia Foundation, 00179 Rome, Italy
| | - Maurizio Muzzi
- Department of Science, University “ROMA TRE”, 00146 Rome, Italy
- IRCCS Santa Lucia Foundation, 00179 Rome, Italy
| | - Antonella Sgura
- Department of Science, University “ROMA TRE”, 00146 Rome, Italy
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7
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The Journey of Mitochondrial Protein Import and the Roadmap to Follow. Int J Mol Sci 2023; 24:ijms24032479. [PMID: 36768800 PMCID: PMC9916854 DOI: 10.3390/ijms24032479] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 01/19/2023] [Accepted: 01/25/2023] [Indexed: 01/31/2023] Open
Abstract
Mitochondria are double membrane-bound organelles that play critical functions in cells including metabolism, energy production, regulation of intrinsic apoptosis, and maintenance of calcium homeostasis. Mitochondria are fascinatingly equipped with their own genome and machinery for transcribing and translating 13 essential proteins of the oxidative phosphorylation system (OXPHOS). The rest of the proteins (99%) that function in mitochondria in the various pathways described above are nuclear-transcribed and synthesized as precursors in the cytosol. These proteins are imported into the mitochondria by the unique mitochondrial protein import system that consists of seven machineries. Proper functioning of the mitochondrial protein import system is crucial for optimal mitochondrial deliverables, as well as mitochondrial and cellular homeostasis. Impaired mitochondrial protein import leads to proteotoxic stress in both mitochondria and cytosol, inducing mitochondrial unfolded protein response (UPRmt). Altered UPRmt is associated with the development of various disease conditions including neurodegenerative and cardiovascular diseases, as well as cancer. This review sheds light on the molecular mechanisms underlying the import of nuclear-encoded mitochondrial proteins, the consequences of defective mitochondrial protein import, and the pathological conditions that arise due to altered UPRmt.
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Udroiu I, Marinaccio J, Sgura A. Many Functions of Telomerase Components: Certainties, Doubts, and Inconsistencies. Int J Mol Sci 2022; 23:ijms232315189. [PMID: 36499514 PMCID: PMC9736166 DOI: 10.3390/ijms232315189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 11/23/2022] [Accepted: 11/29/2022] [Indexed: 12/12/2022] Open
Abstract
A growing number of studies have evidenced non-telomeric functions of "telomerase". Almost all of them, however, investigated the non-canonical effects of the catalytic subunit TERT, and not the telomerase ribonucleoprotein holoenzyme. These functions mainly comprise signal transduction, gene regulation and the increase of anti-oxidative systems. Although less studied, TERC (the RNA component of telomerase) has also been shown to be involved in gene regulation, as well as other functions. All this has led to the publication of many reviews on the subject, which, however, are often disseminating personal interpretations of experimental studies of other researchers as original proofs. Indeed, while some functions such as gene regulation seem ascertained, especially because mechanistic findings have been provided, other ones remain dubious and/or are contradicted by other direct or indirect evidence (e.g., telomerase activity at double-strand break site, RNA polymerase activity of TERT, translation of TERC, mitochondrion-processed TERC). In a critical study of the primary evidence so far obtained, we show those functions for which there is consensus, those showing contradictory results and those needing confirmation. The resulting picture, together with some usually neglected aspects, seems to indicate a link between TERT and TERC functions and cellular stemness and gives possible directions for future research.
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Heidorn-Czarna M, Maziak A, Janska H. Protein Processing in Plant Mitochondria Compared to Yeast and Mammals. FRONTIERS IN PLANT SCIENCE 2022; 13:824080. [PMID: 35185991 PMCID: PMC8847149 DOI: 10.3389/fpls.2022.824080] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2021] [Accepted: 01/12/2022] [Indexed: 05/02/2023]
Abstract
Limited proteolysis, called protein processing, is an essential post-translational mechanism that controls protein localization, activity, and in consequence, function. This process is prevalent for mitochondrial proteins, mainly synthesized as precursor proteins with N-terminal sequences (presequences) that act as targeting signals and are removed upon import into the organelle. Mitochondria have a distinct and highly conserved proteolytic system that includes proteases with sole function in presequence processing and proteases, which show diverse mitochondrial functions with limited proteolysis as an additional one. In virtually all mitochondria, the primary processing of N-terminal signals is catalyzed by the well-characterized mitochondrial processing peptidase (MPP). Subsequently, a second proteolytic cleavage occurs, leading to more stabilized residues at the newly formed N-terminus. Lately, mitochondrial proteases, intermediate cleavage peptidase 55 (ICP55) and octapeptidyl protease 1 (OCT1), involved in proteolytic cleavage after MPP and their substrates have been described in the plant, yeast, and mammalian mitochondria. Mitochondrial proteins can also be processed by removing a peptide from their N- or C-terminus as a maturation step during insertion into the membrane or as a regulatory mechanism in maintaining their function. This type of limited proteolysis is characteristic for processing proteases, such as IMP and rhomboid proteases, or the general mitochondrial quality control proteases ATP23, m-AAA, i-AAA, and OMA1. Identification of processing protease substrates and defining their consensus cleavage motifs is now possible with the help of large-scale quantitative mass spectrometry-based N-terminomics, such as combined fractional diagonal chromatography (COFRADIC), charge-based fractional diagonal chromatography (ChaFRADIC), or terminal amine isotopic labeling of substrates (TAILS). This review summarizes the current knowledge on the characterization of mitochondrial processing peptidases and selected N-terminomics techniques used to uncover protease substrates in the plant, yeast, and mammalian mitochondria.
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Yip J, Wang S, Tan J, Lim TK, Lin Q, Yu Z, Karmon O, Pines O, Lehming N. Fumarase affects the deoxyribonucleic acid damage response by protecting the mitochondrial desulfurase Nfs1p from modification and inactivation. iScience 2021; 24:103354. [PMID: 34805801 PMCID: PMC8590083 DOI: 10.1016/j.isci.2021.103354] [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: 07/25/2021] [Revised: 09/16/2021] [Accepted: 10/22/2021] [Indexed: 10/31/2022] Open
Abstract
The Krebs cycle enzyme fumarase, which has been identified as a tumor suppressor, is involved in the deoxyribonucleic acid (DNA) damage response (DDR) in human, yeast, and bacterial cells. We have found that the overexpression of the cysteine desulfurase Nfs1p restores DNA repair in fumarase-deficient yeast cells. Nfs1p accumulates inactivating post-translational modifications in yeast cells lacking fumarase under conditions of DNA damage. Our model is that in addition to metabolic signaling of the DDR in the nucleus, fumarase affects the DDR by protecting the desulfurase Nfs1p in mitochondria from modification and inactivation. Fumarase performs this protection by directly binding to Nfs1p in mitochondria and enabling, the maintenance, via metabolism, of a non-oxidizing environment in mitochondria. Nfs1p is required for the formation of Fe-S clusters, which are essential cofactors for DNA repair enzymes. Thus, we propose that the overexpression of Nfs1p overcomes the lack of fumarase by enhancing the activity of DNA repair enzymes.
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Affiliation(s)
- Joyce Yip
- Department of Microbiology and Immunology, Cancer Programme at NUSMED, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Block MD4, Level 5, Singapore 117545, Singapore
| | - Suqing Wang
- Department of Microbiology and Immunology, Cancer Programme at NUSMED, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Block MD4, Level 5, Singapore 117545, Singapore
| | - Jasper Tan
- Department of Microbiology and Immunology, Cancer Programme at NUSMED, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Block MD4, Level 5, Singapore 117545, Singapore
| | - Teck Kwang Lim
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore, Singapore
| | - Qingsong Lin
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore, Singapore
| | - Zhang Yu
- Department of Microbiology and Molecular Genetics, IMRIC, Faculty of Medicine, Hebrew University of Jerusalem, Israel; CREATE-NUS-HUJ Program and Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Ofri Karmon
- Department of Microbiology and Molecular Genetics, IMRIC, Faculty of Medicine, Hebrew University of Jerusalem, Israel; CREATE-NUS-HUJ Program and Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Ophry Pines
- Department of Microbiology and Molecular Genetics, IMRIC, Faculty of Medicine, Hebrew University of Jerusalem, Israel; CREATE-NUS-HUJ Program and Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Norbert Lehming
- Department of Microbiology and Immunology, Cancer Programme at NUSMED, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Block MD4, Level 5, Singapore 117545, Singapore
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Aminopeptidases trim Xaa-Pro proteins, initiating their degradation by the Pro/N-degron pathway. Proc Natl Acad Sci U S A 2021; 118:2115430118. [PMID: 34663735 DOI: 10.1073/pnas.2115430118] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/12/2021] [Indexed: 12/26/2022] Open
Abstract
N-degron pathways are proteolytic systems that recognize proteins bearing N-terminal (Nt) degradation signals (degrons) called N-degrons. Our previous work identified Gid4 as a recognition component (N-recognin) of the Saccharomyces cerevisiae proteolytic system termed the proline (Pro)/N-degron pathway. Gid4 is a subunit of the oligomeric glucose-induced degradation (GID) ubiquitin ligase. Gid4 targets proteins through the binding to their Nt-Pro residue. Gid4 is also required for degradation of Nt-Xaa-Pro (Xaa is any amino acid residue) proteins such as Nt-[Ala-Pro]-Aro10 and Nt-[Ser-Pro]-Pck1, with Pro at position 2. Here, we show that specific aminopeptidases function as components of the Pro/N-degron pathway by removing Nt-Ala or Nt-Ser and yielding Nt-Pro, which can be recognized by Gid4-GID. Nt-Ala is removed by the previously uncharacterized aminopeptidase Fra1. The enzymatic activity of Fra1 is shown to be essential for the GID-dependent degradation of Nt-[Ala-Pro]-Aro10. Fra1 can also trim Nt-[Ala-Pro-Pro-Pro] (stopping immediately before the last Pro) and thereby can target for degradation a protein bearing this Nt sequence. Nt-Ser is removed largely by the mitochondrial/cytosolic/nuclear aminopeptidase Icp55. These advances are relevant to eukaryotes from fungi to animals and plants, as Fra1, Icp55, and the GID ubiquitin ligase are conserved in evolution. In addition to discovering the mechanism of targeting of Xaa-Pro proteins, these insights have also expanded the diversity of substrates of the Pro/N-degron pathway.
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Zhao F, Zou MH. Role of the Mitochondrial Protein Import Machinery and Protein Processing in Heart Disease. Front Cardiovasc Med 2021; 8:749756. [PMID: 34651031 PMCID: PMC8505727 DOI: 10.3389/fcvm.2021.749756] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 08/26/2021] [Indexed: 12/12/2022] Open
Abstract
Mitochondria are essential organelles for cellular energy production, metabolic homeostasis, calcium homeostasis, cell proliferation, and apoptosis. About 99% of mammalian mitochondrial proteins are encoded by the nuclear genome, synthesized as precursors in the cytosol, and imported into mitochondria by mitochondrial protein import machinery. Mitochondrial protein import systems function not only as independent units for protein translocation, but also are deeply integrated into a functional network of mitochondrial bioenergetics, protein quality control, mitochondrial dynamics and morphology, and interaction with other organelles. Mitochondrial protein import deficiency is linked to various diseases, including cardiovascular disease. In this review, we describe an emerging class of protein or genetic variations of components of the mitochondrial import machinery involved in heart disease. The major protein import pathways, including the presequence pathway (TIM23 pathway), the carrier pathway (TIM22 pathway), and the mitochondrial intermembrane space import and assembly machinery, related translocases, proteinases, and chaperones, are discussed here. This review highlights the importance of mitochondrial import machinery in heart disease, which deserves considerable attention, and further studies are urgently needed. Ultimately, this knowledge may be critical for the development of therapeutic strategies in heart disease.
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Affiliation(s)
- Fujie Zhao
- Center for Molecular and Translational Medicine, Georgia State University, Atlanta, GA, United States
| | - Ming-Hui Zou
- Center for Molecular and Translational Medicine, Georgia State University, Atlanta, GA, United States
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13
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A single m 6A modification in U6 snRNA diversifies exon sequence at the 5' splice site. Nat Commun 2021; 12:3244. [PMID: 34050143 PMCID: PMC8163875 DOI: 10.1038/s41467-021-23457-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Accepted: 04/29/2021] [Indexed: 11/09/2022] Open
Abstract
N6-methyladenosine (m6A) is a modification that plays pivotal roles in RNA metabolism and function, although its functions in spliceosomal U6 snRNA remain unknown. To elucidate its role, we conduct a large-scale transcriptome analysis of a Schizosaccharomyces pombe strain lacking this modification and found a global change of pre-mRNA splicing. The most significantly impacted introns are enriched for adenosine at the fourth position pairing the m6A in U6 snRNA, and exon sequences weakly recognized by U5 snRNA. This suggests cooperative recognition of 5' splice site by U6 and U5 snRNPs, and also a role of m6A facilitating efficient recognition of the splice sites weakly interacting with U5 snRNA, indicating that U6 snRNA m6A relaxes the 5' exon constraint and allows protein sequence diversity along with explosively increasing number of introns over the course of eukaryotic evolution.
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14
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Gomez-Fabra Gala M, Vögtle FN. Mitochondrial proteases in human diseases. FEBS Lett 2021; 595:1205-1222. [PMID: 33453058 DOI: 10.1002/1873-3468.14039] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 12/17/2020] [Accepted: 12/18/2020] [Indexed: 12/15/2022]
Abstract
Mitochondria contain more than 1000 different proteins, including several proteolytic enzymes. These mitochondrial proteases form a complex system that performs limited and terminal proteolysis to build the mitochondrial proteome, maintain, and control its functions or degrade mitochondrial proteins and peptides. During protein biogenesis, presequence proteases cleave and degrade mitochondrial targeting signals to obtain mature functional proteins. Processing by proteases also exerts a regulatory role in modulation of mitochondrial functions and quality control enzymes degrade misfolded, aged, or superfluous proteins. Depending on their different functions and substrates, defects in mitochondrial proteases can affect the majority of the mitochondrial proteome or only a single protein. Consequently, mutations in mitochondrial proteases have been linked to several human diseases. This review gives an overview of the components and functions of the mitochondrial proteolytic machinery and highlights the pathological consequences of dysfunctional mitochondrial protein processing and turnover.
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Affiliation(s)
- Maria Gomez-Fabra Gala
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, Germany.,Faculty of Biology, University of Freiburg, Germany.,Spemann Graduate School of Biology and Medicine, University of Freiburg, Germany
| | - Friederike-Nora Vögtle
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, Germany.,CIBSS-Centre for Integrative Biological Signalling Studies, University of Freiburg, Germany
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15
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Gomez-Casati DF, Busi MV, Barchiesi J, Pagani MA, Marchetti-Acosta NS, Terenzi A. Fe-S Protein Synthesis in Green Algae Mitochondria. PLANTS 2021; 10:plants10020200. [PMID: 33494487 PMCID: PMC7911964 DOI: 10.3390/plants10020200] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 01/13/2021] [Accepted: 01/18/2021] [Indexed: 12/28/2022]
Abstract
Iron and sulfur are two essential elements for all organisms. These elements form the Fe-S clusters that are present as cofactors in numerous proteins and protein complexes related to key processes in cells, such as respiration and photosynthesis, and participate in numerous enzymatic reactions. In photosynthetic organisms, the ISC and SUF Fe-S cluster synthesis pathways are located in organelles, mitochondria, and chloroplasts, respectively. There is also a third biosynthetic machinery in the cytosol (CIA) that is dependent on the mitochondria for its function. The genes and proteins that participate in these assembly pathways have been described mainly in bacteria, yeasts, humans, and recently in higher plants. However, little is known about the proteins that participate in these processes in algae. This review work is mainly focused on releasing the information on the existence of genes and proteins of green algae (chlorophytes) that could participate in the assembly process of Fe-S groups, especially in the mitochondrial ISC and CIA pathways.
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Affiliation(s)
- Diego F. Gomez-Casati
- Correspondence: (D.F.G.-C.); (M.V.B.); Tel.: +54-341-4391955 (ext. 113) (D.F.G.-C. & M.V.B.)
| | - Maria V. Busi
- Correspondence: (D.F.G.-C.); (M.V.B.); Tel.: +54-341-4391955 (ext. 113) (D.F.G.-C. & M.V.B.)
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16
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Friedl J, Knopp MR, Groh C, Paz E, Gould SB, Herrmann JM, Boos F. More than just a ticket canceller: the mitochondrial processing peptidase tailors complex precursor proteins at internal cleavage sites. Mol Biol Cell 2020; 31:2657-2668. [PMID: 32997570 PMCID: PMC8734313 DOI: 10.1091/mbc.e20-08-0524] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 09/21/2020] [Accepted: 09/25/2020] [Indexed: 11/11/2022] Open
Abstract
Most mitochondrial proteins are synthesized as precursors that carry N-terminal presequences. After they are imported into mitochondria, these targeting signals are cleaved off by the mitochondrial processing peptidase (MPP). Using the mitochondrial tandem protein Arg5,6 as a model substrate, we demonstrate that MPP has an additional role in preprotein maturation, beyond the removal of presequences. Arg5,6 is synthesized as a polyprotein precursor that is imported into mitochondria and subsequently separated into two distinct enzymes. This internal processing is performed by MPP, which cleaves the Arg5,6 precursor at its N-terminus and at an internal site. The peculiar organization of Arg5,6 is conserved across fungi and reflects the polycistronic arginine operon in prokaryotes. MPP cleavage sites are also present in other mitochondrial fusion proteins from fungi, plants, and animals. Hence, besides its role as a "ticket canceller" for removal of presequences, MPP exhibits a second conserved activity as an internal processing peptidase for complex mitochondrial precursor proteins.
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Affiliation(s)
- Jana Friedl
- Cell Biology, Technische Universität Kaiserslautern, 67663 Kaiserslautern, Germany
| | - Michael R. Knopp
- Molecular Evolution, Heinrich-Heine-Universität Düsseldorf, 40225 Düsseldorf, Germany
| | - Carina Groh
- Cell Biology, Technische Universität Kaiserslautern, 67663 Kaiserslautern, Germany
| | - Eyal Paz
- Departments of Biochemistry and Molecular Biology, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Sven B. Gould
- Molecular Evolution, Heinrich-Heine-Universität Düsseldorf, 40225 Düsseldorf, Germany
| | - Johannes M. Herrmann
- Cell Biology, Technische Universität Kaiserslautern, 67663 Kaiserslautern, Germany
| | - Felix Boos
- Cell Biology, Technische Universität Kaiserslautern, 67663 Kaiserslautern, Germany
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17
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Using synthetic biology to overcome barriers to stable expression of nitrogenase in eukaryotic organelles. Proc Natl Acad Sci U S A 2020; 117:16537-16545. [PMID: 32601191 PMCID: PMC7368281 DOI: 10.1073/pnas.2002307117] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Stable expression of each component of the nitrogenase system in an active form is a prerequisite for engineering nitrogen fixation in eukaryotic cells. Mitochondria provide an oxygen-depleted environment for the expression of active nitrogenase in plants, but signal peptides are required to target nuclear encoded Nif proteins to this organelle. We demonstrate that one of the structural subunits of nitrogenase, NifD, is itself susceptible to cleavage by mitochondrial processing peptidases from a variety of plant origins, presenting a major challenge to engineering nitrogen fixation in mitochondria. To overcome this issue, we have engineered NifD variants that are resistant to cleavage and retain high levels of nitrogenase activity, thus providing a potential solution for engineering active MoFe protein in plants. Engineering biological nitrogen fixation in eukaryotic cells by direct introduction of nif genes requires elegant synthetic biology approaches to ensure that components required for the biosynthesis of active nitrogenase are stable and expressed in the appropriate stoichiometry. Previously, the NifD subunits of nitrogenase MoFe protein from Azotobacter vinelandii and Klebsiella oxytoca were found to be unstable in yeast and plant mitochondria, respectively, presenting a bottleneck to the assembly of active MoFe protein in eukaryotic cells. In this study, we have delineated the region and subsequently a key residue, NifD-R98, from K. oxytoca that confers susceptibility to protease-mediated degradation in mitochondria. The effect observed is pervasive, as R98 is conserved among all NifD proteins analyzed. NifD proteins from four representative diazotrophs, but not their R98 variants, were observed to be unstable in yeast mitochondria. Furthermore, by reconstituting mitochondrial-processing peptidases (MPPs) from yeast, Oryza sativa, Nicotiana tabacum, and Arabidopsis thaliana in Escherichia coli, we demonstrated that MPPs are responsible for cleavage of NifD. These results indicate a pervasive effect on the stability of NifD proteins in mitochondria resulting from cleavage by MPPs. NifD-R98 variants that retained high levels of nitrogenase activity were obtained, with the potential to stably target active MoFe protein to mitochondria. This reconstitution approach could help preevaluate the stability of Nif proteins for plant expression and paves the way for engineering active nitrogenase in plant organelles.
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18
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Abstract
Synthesis and regulation of lipid levels and identities is critical for a wide variety of cellular functions, including structural and morphological properties of organelles, energy storage, signaling, and stability and function of membrane proteins. Proteolytic cleavage events regulate and/or influence some of these lipid metabolic processes and as a result help modulate their pleiotropic cellular functions. Proteins involved in lipid regulation are proteolytically cleaved for the purpose of their relocalization, processing, turnover, and quality control, among others. The scope of this review includes proteolytic events governing cellular lipid dynamics. After an initial discussion of the classic example of sterol regulatory element-binding proteins, our focus will shift to the mitochondrion, where a range of proteolytic events are critical for normal mitochondrial phospholipid metabolism and enforcing quality control therein. Recently, mitochondrial phospholipid metabolic pathways have been implicated as important for the proliferative capacity of cancers. Thus, the assorted proteases that regulate, monitor, or influence the activity of proteins that are important for phospholipid metabolism represent attractive targets to be manipulated for research purposes and clinical applications.
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Affiliation(s)
- Pingdewinde N. Sam
- Department of Physiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, United States
| | - Erica Avery
- Department of Physiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, United States
| | - Steven M. Claypool
- Department of Physiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, United States
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19
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Singh R, Goyal VD, Kumar A, Sabharwal NS, Makde RD. Crystal structures and biochemical analyses of intermediate cleavage peptidase: role of dynamics in enzymatic function. FEBS Lett 2019; 593:443-454. [PMID: 30582634 DOI: 10.1002/1873-3468.13321] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Revised: 12/19/2018] [Accepted: 12/19/2018] [Indexed: 01/20/2023]
Abstract
Intermediate cleavage peptidase (Icp55) processes a subset of mitochondrial matrix proteins by removing a bulky residue at their N termini, leaving behind smaller N-terminal residues (icp activity). This contributes towards the stability of the mitochondrial proteome. We report crystal structures of yeast Icp55 including one bound to the apstatin inhibitor. Apart from icp activity, the enzyme was found to exhibit Xaa-Pro aminopeptidase activity in vitro. Structural and biochemical data suggest that the enzyme exists in a rapid equilibrium between monomer and dimer. Furthermore, the dimer, and not the monomer, was found to be the active species with loop dynamics at the dimer interface playing an important role in activity. Based on the new evidence, we propose a model for binding and processing of cellular targets by Icp55. DATABASE: The atomic coordinates and structure factors for the structures of Icp55 (code 6A9T, 6A9U, 6A9V) have been deposited in the Protein Data Bank (PDB) (http://www.pdb.org/).
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Affiliation(s)
- Rahul Singh
- High Pressure and Synchrotron Radiation Physics Division, Bhabha Atomic Research Centre, Mumbai, India
| | - Venuka Durani Goyal
- High Pressure and Synchrotron Radiation Physics Division, Bhabha Atomic Research Centre, Mumbai, India
| | - Ashwani Kumar
- High Pressure and Synchrotron Radiation Physics Division, Bhabha Atomic Research Centre, Mumbai, India
| | - Naripjeet Singh Sabharwal
- High Pressure and Synchrotron Radiation Physics Division, Bhabha Atomic Research Centre, Mumbai, India
| | - Ravindra D Makde
- High Pressure and Synchrotron Radiation Physics Division, Bhabha Atomic Research Centre, Mumbai, India
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20
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Pandey A, Pain J, Dziuba N, Pandey AK, Dancis A, Lindahl PA, Pain D. Mitochondria Export Sulfur Species Required for Cytosolic tRNA Thiolation. Cell Chem Biol 2018; 25:738-748.e3. [PMID: 29706592 PMCID: PMC6014917 DOI: 10.1016/j.chembiol.2018.04.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Revised: 03/09/2018] [Accepted: 04/03/2018] [Indexed: 12/15/2022]
Abstract
In eukaryotes, mitochondria have been hypothesized to generate sulfur species required for tRNA thiolation in the cytosol, although no direct evidence thus far exists. Here we have detected these sulfur species, making use of our observation that isolated yeast cytosol alone is unable to thiolate tRNAs but can do so upon addition of mitochondria. Mitochondria were found to utilize the cysteine desulfurase Nfs1 to produce sulfur-containing species with masses ranging from 700 to 1,100 Da. Mitochondria exported these species via the Atm1 transporter in the inner membrane. Once exported to the cytosol, these sulfur species promoted cytosolic tRNA thiolation with no further requirement of mitochondria. Furthermore, we found that the Isu1/2 scaffolds but not the Ssq1 chaperone of the mitochondrial iron-sulfur cluster machinery were required for cytosolic tRNA thiolation, and thus the sulfur utilization pathway bifurcates at the Isu1/2 site for intra-organellar use in mitochondria or export to the cytosol.
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Affiliation(s)
- Alok Pandey
- Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School, Rutgers University, Newark, NJ 07103, USA
| | - Jayashree Pain
- Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School, Rutgers University, Newark, NJ 07103, USA
| | - Nathaniel Dziuba
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
| | - Ashutosh K Pandey
- Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School, Rutgers University, Newark, NJ 07103, USA
| | - Andrew Dancis
- Department of Medicine, Division of Hematology-Oncology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Paul A Lindahl
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA; Department of Chemistry, Texas A&M University, College Station, TX 77843, USA
| | - Debkumar Pain
- Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School, Rutgers University, Newark, NJ 07103, USA.
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21
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Verechshagina NA, Konstantinov YM, Kamenski PA, Mazunin IO. Import of Proteins and Nucleic Acids into Mitochondria. BIOCHEMISTRY (MOSCOW) 2018; 83:643-661. [DOI: 10.1134/s0006297918060032] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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22
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Yeast aconitase mitochondrial import is modulated by interactions of its C and N terminal domains and Ssa1/2 (Hsp70). Sci Rep 2018; 8:5903. [PMID: 29651044 PMCID: PMC5897410 DOI: 10.1038/s41598-018-24068-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Accepted: 03/27/2018] [Indexed: 11/09/2022] Open
Abstract
Molecules of single proteins, echoforms, can be distributed between two (or more) subcellular locations, a phenomenon which we refer to as dual targeting or dual localization. The yeast aconitase gene ACO1 (778 amino acids), encodes a single translation product that is nonetheless dual localized to the cytosol and mitochondria by a reverse translocation mechanism. The solved crystal structure of aconitase isolated from porcine heart mitochondria shows that it has four domains. The first three tightly associated N-terminal domains are tethered to the larger C-terminal fourth domain (C-terminal amino acids 517–778). We have previously shown that the aconitase C terminal domain constitutes an independent dual targeting signal when fused to mitochondria-targeted passenger-proteins. We show that the aconitase N and C-terminal domains interact and that this interaction is important for efficient aconitase post translational import into mitochondria and for aconitase dual targeting (relative levels of aconitase echoforms). Our results suggest a “chaperone-like function” of the C terminal domain towards the N terminal domains which can be modulated by Ssa1/2 (cytosolic Hsp70).
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23
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Singh R, Jamdar SN, Goyal VD, Kumar A, Ghosh B, Makde RD. Structure of the human aminopeptidase XPNPEP3 and comparison of its in vitro activity with Icp55 orthologs: Insights into diverse cellular processes. J Biol Chem 2017; 292:10035-10047. [PMID: 28476889 DOI: 10.1074/jbc.m117.783357] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2017] [Revised: 05/04/2017] [Indexed: 11/06/2022] Open
Abstract
The human aminopeptidase XPNPEP3 is associated with cystic kidney disease and TNF-TNFR2 cellular signaling. Its yeast and plant homolog Icp55 processes several imported mitochondrial matrix proteins leading to their stabilization. However, the molecular basis for the diverse roles of these enzymes in the cell is unknown. Here, we report the crystal structure of human XPNPEP3 with bound apstatin product at 1.65 Å resolution, and we compare its in vitro substrate specificity with those of fungal Icp55 enzymes. In contrast to the suggestions by earlier in vivo studies of mitochondrial processing, we found that these enzymes are genuine Xaa-Pro aminopeptidases, which hydrolyze peptides with proline at the second position (P1'). The mitochondrial processing activity involving cleavage of peptides lacking P1' proline was also detected in the purified enzymes. A wide proline pocket as well as molecular complementarity and capping at the S1 substrate site of XPNPEP3 provide the necessary structural features for processing the mitochondrial substrates. However, this activity was found to be significantly lower as compared with Xaa-Pro aminopeptidase activity. Because of similar activity profiles of Icp55 and XPNPEP3, we propose that XPNPEP3 plays the same mitochondrial role in humans as Icp55 does in yeast. Both Xaa-Pro aminopeptidase and mitochondrial processing activities of XPNPEP3 have implications toward mitochondrial fitness and cystic kidney disease. Furthermore, the presence of both these activities in Icp55 elucidates the unexplained processing of the mitochondrial cysteine desulfurase Nfs1 in yeast. The enzymatic and structural analyses reported here provide a valuable molecular framework for understanding the diverse cellular roles of XPNPEP3.
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Affiliation(s)
- Rahul Singh
- From the High Pressure and Synchrotron Radiation Physics Division and
| | - Sahayog N Jamdar
- Food Technology Division, Bhabha Atomic Research Centre, 400085 Mumbai, India
| | | | - Ashwani Kumar
- From the High Pressure and Synchrotron Radiation Physics Division and
| | - Biplab Ghosh
- From the High Pressure and Synchrotron Radiation Physics Division and
| | - Ravindra D Makde
- From the High Pressure and Synchrotron Radiation Physics Division and
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24
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Correa AF, Bastos IMD, Neves D, Kipnis A, Junqueira-Kipnis AP, de Santana JM. The Activity of a Hexameric M17 Metallo-Aminopeptidase Is Associated With Survival of Mycobacterium tuberculosis. Front Microbiol 2017; 8:504. [PMID: 28396657 PMCID: PMC5366330 DOI: 10.3389/fmicb.2017.00504] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2016] [Accepted: 03/10/2017] [Indexed: 01/06/2023] Open
Abstract
Mycobacterium tuberculosis is one of the most prevalent human pathogens causing millions of deaths in the last years. Moreover, tuberculosis (TB) treatment has become increasingly challenging owing to the emergence of multidrug resistant M. tuberculosis strains. Thus, there is an immediate need for the development of new anti-TB drugs. Proteases appear to be a promising approach and may lead to shortened and effective treatments for drug-resistant TB. Although the M. tuberculosis genome predicts more than 100 genes encoding proteases, only a few of them have been studied. Aminopeptidases constitute a set of proteases that selectively remove amino acids from the N-terminus of proteins and peptides and may act as virulence factors, essential for survival and maintenance of many microbial pathogens. Here, we characterized a leucine aminopeptidase of M. tuberculosis (MtLAP) as a cytosolic oligomeric metallo-aminopeptidase. Molecular and enzymatic properties lead us to classify MtLAP as a typical member of the peptidase family M17. Furthermore, the aminopeptidase inhibitor bestatin strongly inhibited MtLAP activity, in vitro M. tuberculosis growth and macrophage infection. In murine model of TB, bestatin treatment reduced bacterial burden and lesion in the lungs of infected mice. Thus, our data suggest that MtLAP participates in important metabolic pathways of M. tuberculosis necessary for its survival and virulence and consequently may be a promising target for new anti-TB drugs.
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Affiliation(s)
- Andre F Correa
- Laboratório de Interação Patógeno-Hospedeiro, Instituto de Biologia Universidade de BrasíliaBrasília, Brazil; Instituto de Patologia Tropical e Saúde Pública Universidade Federal de GoiásGoiânia, Brazil
| | - Izabela M D Bastos
- Laboratório de Interação Patógeno-Hospedeiro, Instituto de Biologia Universidade de Brasília Brasília, Brazil
| | - David Neves
- Laboratório de Interação Patógeno-Hospedeiro, Instituto de Biologia Universidade de Brasília Brasília, Brazil
| | - Andre Kipnis
- Instituto de Patologia Tropical e Saúde Pública Universidade Federal de Goiás Goiânia, Brazil
| | - Ana P Junqueira-Kipnis
- Instituto de Patologia Tropical e Saúde Pública Universidade Federal de Goiás Goiânia, Brazil
| | - Jaime M de Santana
- Laboratório de Interação Patógeno-Hospedeiro, Instituto de Biologia Universidade de Brasília Brasília, Brazil
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25
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Sulfur Modifications of the Wobble U 34 in tRNAs and their Intracellular Localization in Eukaryotic Cells. Biomolecules 2017; 7:biom7010017. [PMID: 28218716 PMCID: PMC5372729 DOI: 10.3390/biom7010017] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Revised: 02/08/2017] [Accepted: 02/08/2017] [Indexed: 12/21/2022] Open
Abstract
The wobble uridine (U34) of transfer RNAs (tRNAs) for two-box codon recognition, i.e., tRNALysUUU, tRNAGluUUC, and tRNAGlnUUG, harbor a sulfur- (thio-) and a methyl-derivative structure at the second and fifth positions of U34, respectively. Both modifications are necessary to construct the proper anticodon loop structure and to enable them to exert their functions in translation. Thio-modification of U34 (s2U34) is found in both cytosolic tRNAs (cy-tRNAs) and mitochondrial tRNAs (mt-tRNAs). Although l-cysteine desulfurase is required in both cases, subsequent sulfur transfer pathways to cy-tRNAs and mt-tRNAs are different due to their distinct intracellular locations. The s2U34 formation in cy-tRNAs involves a sulfur delivery system required for the biosynthesis of iron-sulfur (Fe/S) clusters and certain resultant Fe/S proteins. This review addresses presumed sulfur delivery pathways for the s2U34 formation in distinct intracellular locations, especially that for cy-tRNAs in comparison with that for mt-tRNAs.
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26
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Ben-Menachem R, Pines O. Detection of Dual Targeting and Dual Function of Mitochondrial Proteins in Yeast. Methods Mol Biol 2017; 1567:179-195. [PMID: 28276019 DOI: 10.1007/978-1-4939-6824-4_11] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Eukaryotic cells are defined by the existence of subcellular compartments and organelles. The localization of a protein to a specific subcellular compartment is one of the most fundamental processes of a living cell. It is well documented that in eukaryotic cells molecules of a single protein can be located in more than one subcellular compartment, a phenomenon termed dual targeting, bimodal targeting, or dual localization. Recently, growing evidence started to accumulate for abundant dual targeting of mitochondrial proteins, which are localized to a second location in the cell, besides this specific organelle. We have termed these dual localized proteins echoforms or echoproteins (echo in Greek denotes repetition). As the research on dual targeting of proteins is developing and evidence is accumulating for high abundance of the phenomenon, there is a growing need for new methods that would allow the identification of dual localized proteins and analysis of their functions in each subcellular compartment. This is particularly critical for single translation products that are encoded by the same gene and are actually derived from the same protein but nevertheless distribute between different subcellular compartments. The above considerations have led us to develop several approaches for studying dual localized proteins and their dual function. These include an α-complementation-based assay, specific depletion, and selection of the individual echoproteins.
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Affiliation(s)
- Reut Ben-Menachem
- Department of Microbiology and Molecular Genetics, IMRIC, Faculty of Medicine, Hebrew University, Jerusalem, Israel
| | - Ophry Pines
- Department of Microbiology and Molecular Genetics, IMRIC, Faculty of Medicine, Hebrew University, Jerusalem, Israel.
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27
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Lionaki E, Gkikas I, Tavernarakis N. Differential Protein Distribution between the Nucleus and Mitochondria: Implications in Aging. Front Genet 2016; 7:162. [PMID: 27695477 PMCID: PMC5025450 DOI: 10.3389/fgene.2016.00162] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Accepted: 09/01/2016] [Indexed: 01/05/2023] Open
Abstract
The coordination of nuclear and mitochondrial genomes plays a pivotal role in maintenance of mitochondrial biogenesis and functionality during stress and aging. Environmental and cellular inputs signal to nucleus and/or mitochondria to trigger interorganellar compensatory responses. Loss of this tightly orchestrated coordination results in loss of cellular homeostasis and underlies various pathologies and age-related diseases. Several signaling cascades that govern interorganellar communication have been revealed up to now, and have been classified as part of the anterograde (nucleus to mitochondria) or retrograde (mitochondrial to nucleus) response. Many of these molecular pathways rely on the dual distribution of nuclear or mitochondrial components under basal or stress conditions. These dually localized components usually engage in specific tasks in their primary organelle of function, whilst upon cellular stimuli, they appear in the other organelle where they engage in the same or a different task, triggering a compensatory stress response. In this review, we focus on protein factors distributed between the nucleus and mitochondria and activated to exert their functions upon basal or stress conditions. We further discuss implications of bi-organellar targeting in the context of aging.
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Affiliation(s)
- Eirini Lionaki
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas Heraklion, Greece
| | - Ilias Gkikas
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas Heraklion, Greece
| | - Nektarios Tavernarakis
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-HellasHeraklion, Greece; Department of Basic Sciences, Faculty of Medicine, University of CreteHeraklion, Greece
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28
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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.
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Eisenberg-Bord M, Schuldiner M. Ground control to major TOM: mitochondria-nucleus communication. FEBS J 2016; 284:196-210. [PMID: 27283924 DOI: 10.1111/febs.13778] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2016] [Revised: 05/23/2016] [Accepted: 06/08/2016] [Indexed: 01/13/2023]
Abstract
Mitochondria have crucial functions in the cell, including ATP generation, iron-sulfur cluster biogenesis, nucleotide biosynthesis, and amino acid metabolism. All of these functions require tight regulation on mitochondrial activity and homeostasis. As mitochondria biogenesis is controlled by the nucleus and almost all mitochondrial proteins are encoded by nuclear genes, a tight communication network between mitochondria and the nucleus has evolved, which includes signaling cascades, proteins which are dual-localized to the two compartments, and sensing of mitochondrial products by nuclear proteins. All of these enable a crosstalk between mitochondria and the nucleus that allows the 'ground control' to get information on mitochondria's status. Such information facilitates the creation of a cellular balance of mitochondrial status with energetic needs. This communication also allows a transcriptional response in case mitochondrial function is impaired aimed to restore mitochondrial homeostasis. As mitochondrial dysfunction is related to a growing number of genetic diseases as well as neurodegenerative conditions and aging, elucidating the mechanisms governing the mitochondrial/nuclear communication should progress a better understanding of mitochondrial dysfunctions.
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Affiliation(s)
| | - Maya Schuldiner
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
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Carrie C, Venne AS, Zahedi RP, Soll J. Identification of cleavage sites and substrate proteins for two mitochondrial intermediate peptidases in Arabidopsis thaliana. JOURNAL OF EXPERIMENTAL BOTANY 2015; 66:2691-708. [PMID: 25732537 PMCID: PMC4986872 DOI: 10.1093/jxb/erv064] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Most mitochondrial proteins contain an N-terminal targeting signal that is removed by specific proteases following import. In plant mitochondria, only mitochondrial processing peptidase (MPP) has been characterized to date. Therefore, we sought to determine the substrates and cleavage sites of the Arabidopsis thaliana homologues to the yeast Icp55 and Oct1 proteins, using the newly developed ChaFRADIC method for N-terminal protein sequencing. We identified 88 and seven putative substrates for Arabidopsis ICP55 and OCT1, respectively. It was determined that the Arabidopsis ICP55 contains an almost identical cleavage site to that of Icp55 from yeast. However, it can also remove a far greater range of amino acids. The OCT1 substrates from Arabidopsis displayed no consensus cleavage motif, and do not contain the classical -10R motif identified in other eukaryotes. Arabidopsis OCT1 can also cleave presequences independently, without the prior cleavage of MPP. It was concluded that while both OCT1 and ICP55 were probably acquired early on in the evolution of mitochondria, their substrate profiles and cleavage sites have either remained very similar or diverged completely.
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Affiliation(s)
- Chris Carrie
- Department of Biology I, Botany, Ludwig-Maximilians Universität München, Großhaderner Strasse 2-4, D-82152 Planegg-Martinsried, Germany
| | - A Saskia Venne
- Leibniz-Institut für Analytische Wissenschaften - ISAS - e.V., Otto-Hahn-Str. 11, D-44139 Dortmund, Germany
| | - René P Zahedi
- Leibniz-Institut für Analytische Wissenschaften - ISAS - e.V., Otto-Hahn-Str. 11, D-44139 Dortmund, Germany
| | - Jürgen Soll
- Department of Biology I, Botany, Ludwig-Maximilians Universität München, Großhaderner Strasse 2-4, D-82152 Planegg-Martinsried, Germany Munich Centre for Integrated Protein Science, CiPSM, Ludwig-Maximilians Universität München, Feodor-Lynen-Strasse 25, D-81377 Munich, Germany
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Bohovych I, Chan SS, Khalimonchuk O. Mitochondrial protein quality control: the mechanisms guarding mitochondrial health. Antioxid Redox Signal 2015; 22:977-94. [PMID: 25546710 PMCID: PMC4390190 DOI: 10.1089/ars.2014.6199] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Accepted: 12/20/2014] [Indexed: 12/20/2022]
Abstract
SIGNIFICANCE Mitochondria are complex dynamic organelles pivotal for cellular physiology and human health. Failure to maintain mitochondrial health leads to numerous maladies that include late-onset neurodegenerative diseases and cardiovascular disorders. Furthermore, a decline in mitochondrial health is prevalent with aging. A set of evolutionary conserved mechanisms known as mitochondrial quality control (MQC) is involved in recognition and correction of the mitochondrial proteome. RECENT ADVANCES Here, we review current knowledge and latest developments in MQC. We particularly focus on the proteolytic aspect of MQC and its impact on health and aging. CRITICAL ISSUES While our knowledge about MQC is steadily growing, critical gaps remain in the mechanistic understanding of how MQC modules sense damage and preserve mitochondrial welfare, particularly in higher organisms. FUTURE DIRECTIONS Delineating how coordinated action of the MQC modules orchestrates physiological responses on both organellar and cellular levels will further elucidate the current picture of MQC's role and function in health, cellular stress, and degenerative diseases.
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Affiliation(s)
- Iryna Bohovych
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, Nebraska
- Nebraska Redox Biology Center, University of Nebraska-Lincoln, Lincoln, Nebraska
| | - Sherine S.L. Chan
- Department of Drug Discovery and Biomedical Sciences, Medical University of South Carolina, Charleston, South Carolina
| | - Oleh Khalimonchuk
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, Nebraska
- Nebraska Redox Biology Center, University of Nebraska-Lincoln, Lincoln, Nebraska
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Köhler D, Montandon C, Hause G, Majovsky P, Kessler F, Baginsky S, Agne B. Characterization of chloroplast protein import without Tic56, a component of the 1-megadalton translocon at the inner envelope membrane of chloroplasts. PLANT PHYSIOLOGY 2015; 167:972-90. [PMID: 25588737 PMCID: PMC4348784 DOI: 10.1104/pp.114.255562] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2014] [Accepted: 01/14/2015] [Indexed: 05/17/2023]
Abstract
We report on the characterization of Tic56, a unique component of the recently identified 1-MD translocon at the inner envelope membrane of chloroplasts (TIC) in Arabidopsis (Arabidopsis thaliana) comprising Tic20, Tic100, and Tic214. We isolated Tic56 by copurification with Tandem Affinity Purification-tagged Toc159 in the absence of precursor protein, indicating spontaneous and translocation-independent formation of the translocon at the outer envelope membrane of chloroplasts (TOC) and TIC supercomplexes. Tic56 mutant plants have an albino phenotype and are unable to grow without an external carbon source. Using specific enrichment of protein amino termini, we analyzed the tic56-1 and plastid protein import2 (toc159) mutants to assess the in vivo import capacity of plastids in mutants of an outer and inner envelope component of the anticipated TOC-TIC supercomplex. Inboth mutants, we observed processing of several import substrates belonging to various pathways. Our results suggest that despite the severe developmental defects, protein import into Tic56-deficient plastids is functional to a considerable degree, indicating the existence of alternative translocases at the inner envelope membrane.
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Verner Z, Basu S, Benz C, Dixit S, Dobáková E, Faktorová D, Hashimi H, Horáková E, Huang Z, Paris Z, Peña-Diaz P, Ridlon L, Týč J, Wildridge D, Zíková A, Lukeš J. Malleable mitochondrion of Trypanosoma brucei. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2015; 315:73-151. [PMID: 25708462 DOI: 10.1016/bs.ircmb.2014.11.001] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The importance of mitochondria for a typical aerobic eukaryotic cell is undeniable, as the list of necessary mitochondrial processes is steadily growing. Here, we summarize the current knowledge of mitochondrial biology of an early-branching parasitic protist, Trypanosoma brucei, a causative agent of serious human and cattle diseases. We present a comprehensive survey of its mitochondrial pathways including kinetoplast DNA replication and maintenance, gene expression, protein and metabolite import, major metabolic pathways, Fe-S cluster synthesis, ion homeostasis, organellar dynamics, and other processes. As we describe in this chapter, the single mitochondrion of T. brucei is everything but simple and as such rivals mitochondria of multicellular organisms.
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Affiliation(s)
- Zdeněk Verner
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Czech Republic; Present address: Faculty of Natural Sciences, Comenius University, Bratislava, Slovakia; Present address: Faculty of Sciences, Charles University, Prague, Czech Republic
| | - Somsuvro Basu
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Czech Republic; Faculty of Sciences, University of South Bohemia, České Budějovice (Budweis), Czech Republic; Present address: Institut für Zytobiologie und Zytopathologie, Philipps-Universität Marburg, Germany
| | - Corinna Benz
- Faculty of Sciences, University of South Bohemia, České Budějovice (Budweis), Czech Republic
| | - Sameer Dixit
- Faculty of Sciences, University of South Bohemia, České Budějovice (Budweis), Czech Republic
| | - Eva Dobáková
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Czech Republic; Present address: Faculty of Natural Sciences, Comenius University, Bratislava, Slovakia
| | - Drahomíra Faktorová
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Czech Republic; Faculty of Sciences, University of South Bohemia, České Budějovice (Budweis), Czech Republic
| | - Hassan Hashimi
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Czech Republic; Faculty of Sciences, University of South Bohemia, České Budějovice (Budweis), Czech Republic
| | - Eva Horáková
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Czech Republic
| | - Zhenqiu Huang
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Czech Republic; Faculty of Sciences, University of South Bohemia, České Budějovice (Budweis), Czech Republic
| | - Zdeněk Paris
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Czech Republic
| | - Priscila Peña-Diaz
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Czech Republic
| | - Lucie Ridlon
- Faculty of Sciences, University of South Bohemia, České Budějovice (Budweis), Czech Republic; Present address: Salk Institute, La Jolla, San Diego, USA
| | - Jiří Týč
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Czech Republic; Faculty of Sciences, University of South Bohemia, České Budějovice (Budweis), Czech Republic
| | - David Wildridge
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Czech Republic
| | - Alena Zíková
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Czech Republic; Faculty of Sciences, University of South Bohemia, České Budějovice (Budweis), Czech Republic
| | - Julius Lukeš
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Czech Republic; Faculty of Sciences, University of South Bohemia, České Budějovice (Budweis), Czech Republic
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Kalderon B, Pines O. Protein folding as a driving force for dual protein targeting in eukaryotes. Front Mol Biosci 2014; 1:23. [PMID: 25988164 PMCID: PMC4428415 DOI: 10.3389/fmolb.2014.00023] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Accepted: 10/28/2014] [Indexed: 01/19/2023] Open
Abstract
It is well documented that in eukaryotic cells molecules of one protein can be located in several subcellular locations, a phenomenon termed dual targeting, dual localization, or dual distribution. The differently localized identical or nearly identical proteins are termed “echoforms.” Our conventional definition of dual targeted proteins refers to situations in which one of the echoforms is translocated through/into a membrane. Thus, dual targeted proteins are recognized by at least one organelle's receptors and translocation machineries within the lipid bilayer. In this review we attempt to evaluate mechanisms and situations in which protein folding is the major determinant of dual targeting and of the relative distribution levels of echoforms in the subcellular compartments of the eukaryotic cell. We show that the decisive folding step can occur prior, during or after translocation through the bilayer of a biological membrane. This phenomenon involves folding catalysts in the cell such as chaperones, proteases and modification enzymes, and targeting processes such as signal recognition, translocation through membranes, trapping, retrotranslocation and reverse translocation.
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Affiliation(s)
- Bella Kalderon
- Department of Microbiology and Molecular Genetics, Faculty of Medicine, Institute for Medical Research Israel-Canada, Hebrew University of Jerusalem Jerusalem, Israel
| | - Ophry Pines
- Department of Microbiology and Molecular Genetics, Faculty of Medicine, Institute for Medical Research Israel-Canada, Hebrew University of Jerusalem Jerusalem, Israel ; CREATE-NUS-HUJ Cellular and Molecular Mechanisms of Inflammation Program, National University of Singapore Singapore, Singapore
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36
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Manicki M, Majewska J, Ciesielski S, Schilke B, Blenska A, Kominek J, Marszalek J, Craig EA, Dutkiewicz R. Overlapping binding sites of the frataxin homologue assembly factor and the heat shock protein 70 transfer factor on the Isu iron-sulfur cluster scaffold protein. J Biol Chem 2014; 289:30268-30278. [PMID: 25228696 PMCID: PMC4215211 DOI: 10.1074/jbc.m114.596726] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Revised: 09/12/2014] [Indexed: 11/06/2022] Open
Abstract
In mitochondria FeS clusters, prosthetic groups critical for the activity of many proteins, are first assembled on Isu, a 14-kDa scaffold protein, and then transferred to recipient apoproteins. The assembly process involves interaction of Isu with both Nfs1, the cysteine desulfurase serving as a sulfur donor, and the yeast frataxin homolog (Yfh1) serving as a regulator of desulfurase activity and/or iron donor. Here, based on the results of biochemical experiments with purified wild-type and variant proteins, we report that interaction of Yfh1 with both Nfs1 and Isu are required for formation of a stable tripartite assembly complex. Disruption of either Yfh1-Isu or Nfs1-Isu interactions destabilizes the complex. Cluster transfer to recipient apoprotein is known to require the interaction of Isu with the J-protein/Hsp70 molecular chaperone pair, Jac1 and Ssq1. Here we show that the Yfh1 interaction with Isu involves the PVK sequence motif, which is also the site key for the interaction of Isu with Hsp70 Ssq1. Coupled with our previous observation that Nfs1 and Jac1 binding to Isu is mutually exclusive due to partially overlapping binding sites, we propose that such mutual exclusivity of cluster assembly factor (Nfs1/Yfh1) and cluster transfer factor (Jac1/Ssq1) binding to Isu has functional consequences for the transition from the assembly process to the transfer process, and thus regulation of the biogenesis of FeS cluster proteins.
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Affiliation(s)
- Mateusz Manicki
- Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Gdansk 80822, Poland and
| | - Julia Majewska
- Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Gdansk 80822, Poland and; Department of Biochemistry, University of Wisconsin, Madison, Wisconsin 53706
| | - Szymon Ciesielski
- Department of Biochemistry, University of Wisconsin, Madison, Wisconsin 53706
| | - Brenda Schilke
- Department of Biochemistry, University of Wisconsin, Madison, Wisconsin 53706
| | - Anna Blenska
- Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Gdansk 80822, Poland and
| | - Jacek Kominek
- Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Gdansk 80822, Poland and
| | - Jaroslaw Marszalek
- Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Gdansk 80822, Poland and; Department of Biochemistry, University of Wisconsin, Madison, Wisconsin 53706.
| | - Elizabeth A Craig
- Department of Biochemistry, University of Wisconsin, Madison, Wisconsin 53706.
| | - Rafal Dutkiewicz
- Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Gdansk 80822, Poland and
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Pratap Singh K, Zaidi A, Anwar S, Bimal S, Das P, Ali V. Reactive oxygen species regulates expression of iron-sulfur cluster assembly protein IscS of Leishmania donovani. Free Radic Biol Med 2014; 75:195-209. [PMID: 25062827 DOI: 10.1016/j.freeradbiomed.2014.07.017] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Revised: 07/10/2014] [Accepted: 07/14/2014] [Indexed: 01/18/2023]
Abstract
The cysteine desulfurase, IscS, is a highly conserved and essential component of the mitochondrial iron-sulfur cluster (ISC) system that serves as a sulfur donor for Fe-S clusters biogenesis. Fe-S clusters are versatile and labile cofactors of proteins that orchestrate a wide array of essential metabolic processes, such as energy generation and ribosome biogenesis. However, no information regarding the role of IscS or its regulation is available in Leishmania, an evolving pathogen model with rapidly developing drug resistance. In this study, we characterized LdIscS to investigate the ISC system in AmpB-sensitive vs resistant isolates of L. donovani and to understand its regulation. We observed an upregulated Fe-S protein activity in AmpB-resistant isolates but, in contrast to our expectations, LdIscS expression was upregulated in the sensitive strain. However, further investigations showed that LdIscS expression is positively correlated with ROS level and negatively correlated with Fe-S protein activity, independent of strain sensitivity. Thus, our results suggested that LdIscS expression is regulated by ROS level with Fe-S clusters/proteins acting as ROS sensors. Moreover, the direct evidence of a mechanism, in support of our results, is provided by dose-dependent induction of LdIscS-GFP as well as endogenous LdIscS in L. donovani promastigotes by three different ROS inducers: H2O2, menadione, and Amphotericin B. We postulate that LdIscS is upregulated for de novo synthesis or repair of ROS damaged Fe-S clusters. Our results reveal a novel mechanism for regulation of IscS expression that may help parasite survival under oxidative stress conditions encountered during infection of macrophages and suggest a cross talk between two seemingly unrelated metabolic pathways, the ISC system and redox metabolism in L. donovani.
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Affiliation(s)
- Krishn Pratap Singh
- Laboratory of Molecular Biochemistry and Cell Biology, Department of Biochemistry, Rajendra Memorial Research Institute of Medical Sciences, Agamkuan, Patna, India 800007
| | - Amir Zaidi
- Laboratory of Molecular Biochemistry and Cell Biology, Department of Biochemistry, Rajendra Memorial Research Institute of Medical Sciences, Agamkuan, Patna, India 800007
| | - Shadab Anwar
- Laboratory of Molecular Biochemistry and Cell Biology, Department of Biochemistry, Rajendra Memorial Research Institute of Medical Sciences, Agamkuan, Patna, India 800007
| | - Sanjeev Bimal
- Department of Immunology, Rajendra Memorial Research Institute of Medical Sciences, Agamkuan, Patna, India 800007
| | - Pradeep Das
- Department of Molecular Biology, Rajendra Memorial Research Institute of Medical Sciences, Agamkuan, Patna, India 800007
| | - Vahab Ali
- Laboratory of Molecular Biochemistry and Cell Biology, Department of Biochemistry, Rajendra Memorial Research Institute of Medical Sciences, Agamkuan, Patna, India 800007.
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38
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Lukeš J, Basu S. Fe/S protein biogenesis in trypanosomes - A review. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2014; 1853:1481-92. [PMID: 25196712 DOI: 10.1016/j.bbamcr.2014.08.015] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2014] [Revised: 08/25/2014] [Accepted: 08/29/2014] [Indexed: 12/15/2022]
Abstract
Trypanosoma brucei, the causative agent of the African sleeping sickness of humans, and other kinetoplastid flagellates belong to the eukarytotic supergroup Excavata. This early-branching model protist is known for a broad range of unique features. As it is amenable to most techniques of forward and reverse genetics, T. brucei was subject to several studies of its iron-sulfur (Fe/S) protein biogenesis and thus represents the best studied excavate eukaryote. Here we review what is known about the Fe/S protein biogenesis of T. brucei, and focus especially on the comparative and evolutionary interesting aspects. We also explore the connections between the well-known and quite conserved ISC and CIA machineries and the tRNA thiolation pathway. Moreover, the Fe/S cluster protein biogenesis is dissected in the procyclic stage of T. brucei which has an active mitochondrion, as well as in its pathogenic bloodstream stage with a metabolically repressed organelle. This article is part of a Special Issue entitled: Fe/S proteins: Analysis, structure, function, biogenesis and diseases.
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Affiliation(s)
- Julius Lukeš
- Biology Centre, Institute of Parasitology, Czech Academy of Sciences and Faculty of Science, University of South Bohemia, 37005 České Budějovice (Budweis), Czech Republic.
| | - Somsuvro Basu
- Biology Centre, Institute of Parasitology, Czech Academy of Sciences and Faculty of Science, University of South Bohemia, 37005 České Budějovice (Budweis), Czech Republic
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39
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Woellhaf MW, Hansen KG, Garth C, Herrmann JM. Import of ribosomal proteins into yeast mitochondria. Biochem Cell Biol 2014; 92:489-98. [PMID: 24943357 DOI: 10.1139/bcb-2014-0029] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Mitochondrial ribosomes of baker's yeast contain at least 78 protein subunits. All but one of these proteins are nuclear-encoded, synthesized on cytosolic ribosomes, and imported into the matrix for biogenesis. The import of matrix proteins typically relies on N-terminal mitochondrial targeting sequences that form positively charged amphipathic helices. Interestingly, the N-terminal regions of many ribosomal proteins do not closely match the characteristics of matrix targeting sequences, suggesting that the import processes of these proteins might deviate to some extent from the general import route. So far, the biogenesis of only two ribosomal proteins, Mrpl32 and Mrp10, was studied experimentally and indeed showed surprising differences to the import of other preproteins. In this review article we summarize the current knowledge on the transport of proteins into the mitochondrial matrix, and thereby specifically focus on proteins of the mitochondrial ribosome.
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Affiliation(s)
- Michael W Woellhaf
- a Cell Biology, University of Kaiserslautern, Erwin-Schrödinger-Strasse 13, 67663 Kaiserslautern, Germany
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40
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Harbauer AB, Zahedi RP, Sickmann A, Pfanner N, Meisinger C. The protein import machinery of mitochondria-a regulatory hub in metabolism, stress, and disease. Cell Metab 2014; 19:357-72. [PMID: 24561263 DOI: 10.1016/j.cmet.2014.01.010] [Citation(s) in RCA: 282] [Impact Index Per Article: 28.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Mitochondria fulfill central functions in bioenergetics, metabolism, and apoptosis. They import more than 1,000 different proteins from the cytosol. It had been assumed that the protein import machinery is constitutively active and not subject to detailed regulation. However, recent studies indicate that mitochondrial protein import is regulated at multiple levels connected to cellular metabolism, signaling, stress, and pathogenesis of diseases. Here, we discuss the molecular mechanisms of import regulation and their implications for mitochondrial homeostasis. The protein import activity can function as a sensor of mitochondrial fitness and provides a direct means of regulating biogenesis, composition, and turnover of the organelle.
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Affiliation(s)
- Angelika B Harbauer
- Institut für Biochemie und Molekularbiologie, ZBMZ, Universität Freiburg, 79104 Freiburg, Germany; Trinationales Graduiertenkolleg 1478, Universität Freiburg, 79104 Freiburg, Germany; Faculty of Biology, Universität Freiburg, 79104 Freiburg, Germany; BIOSS Centre for Biological Signalling Studies, Universität Freiburg, 79104 Freiburg, Germany
| | - René P Zahedi
- Leibniz-Institute for Analytical Sciences-ISAS-e.V., 44139 Dortmund, Germany
| | - Albert Sickmann
- Leibniz-Institute for Analytical Sciences-ISAS-e.V., 44139 Dortmund, Germany; Medizinisches Proteom-Center, Ruhr-Universität Bochum, 44801 Bochum, Germany
| | - Nikolaus Pfanner
- Institut für Biochemie und Molekularbiologie, ZBMZ, Universität Freiburg, 79104 Freiburg, Germany; BIOSS Centre for Biological Signalling Studies, Universität Freiburg, 79104 Freiburg, Germany.
| | - Chris Meisinger
- Institut für Biochemie und Molekularbiologie, ZBMZ, Universität Freiburg, 79104 Freiburg, Germany; BIOSS Centre for Biological Signalling Studies, Universität Freiburg, 79104 Freiburg, Germany.
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41
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Kovárová J, Horáková E, Changmai P, Vancová M, Lukeš J. Mitochondrial and nucleolar localization of cysteine desulfurase Nfs and the scaffold protein Isu in Trypanosoma brucei. EUKARYOTIC CELL 2014; 13:353-62. [PMID: 24243795 PMCID: PMC3957590 DOI: 10.1128/ec.00235-13] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2013] [Accepted: 11/12/2013] [Indexed: 01/09/2023]
Abstract
Trypanosoma brucei has a complex life cycle during which its single mitochondrion is subjected to major metabolic and morphological changes. While the procyclic stage (PS) of the insect vector contains a large and reticulated mitochondrion, its counterpart in the bloodstream stage (BS) parasitizing mammals is highly reduced and seems to be devoid of most functions. We show here that key Fe-S cluster assembly proteins are still present and active in this organelle and that produced clusters are incorporated into overexpressed enzymes. Importantly, the cysteine desulfurase Nfs, equipped with the nuclear localization signal, was detected in the nucleolus of both T. brucei life stages. The scaffold protein Isu, an interacting partner of Nfs, was also found to have a dual localization in the mitochondrion and the nucleolus, while frataxin and both ferredoxins are confined to the mitochondrion. Moreover, upon depletion of Isu, cytosolic tRNA thiolation dropped in the PS but not BS parasites.
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Affiliation(s)
- Julie Kovárová
- Biology Center, Institute of Parasitology, Czech Academy of Sciences and Faculty of Sciences, University of South Bohemia, České Budějovice (Budweis), Czech Republic
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42
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Pandey A, Gordon DM, Pain J, Stemmler TL, Dancis A, Pain D. Frataxin directly stimulates mitochondrial cysteine desulfurase by exposing substrate-binding sites, and a mutant Fe-S cluster scaffold protein with frataxin-bypassing ability acts similarly. J Biol Chem 2013; 288:36773-86. [PMID: 24217246 PMCID: PMC3873537 DOI: 10.1074/jbc.m113.525857] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2013] [Revised: 11/09/2013] [Indexed: 01/17/2023] Open
Abstract
For iron-sulfur (Fe-S) cluster synthesis in mitochondria, the sulfur is derived from the amino acid cysteine by the cysteine desulfurase activity of Nfs1. The enzyme binds the substrate cysteine in the pyridoxal phosphate-containing site, and a persulfide is formed on the active site cysteine in a manner depending on the accessory protein Isd11. The persulfide is then transferred to the scaffold Isu, where it combines with iron to form the Fe-S cluster intermediate. Frataxin is implicated in the process, although it is unclear where and how, and deficiency causes Friedreich ataxia. Using purified proteins and isolated mitochondria, we show here that the yeast frataxin homolog (Yfh1) directly and specifically stimulates cysteine binding to Nfs1 by exposing substrate-binding sites. This novel function of frataxin does not require iron, Isu1, or Isd11. Once bound to Nfs1, the substrate cysteine is the source of the Nfs1 persulfide, but this step is independent of frataxin and strictly dependent on Isd11. Recently, a point mutation in Isu1 was found to bypass many frataxin functions. The data presented here show that the Isu1 suppressor mimics the frataxin effects on Nfs1, explaining the bypassing activity. We propose a regulatory mechanism for the Nfs1 persulfide-forming activity. Specifically, at least two separate conformational changes must occur in the enzyme for optimum activity as follows: one is mediated by frataxin interaction that exposes the "buried" substrate-binding sites, and the other is mediated by Isd11 interaction that brings the bound substrate cysteine and the active site cysteine in proximity for persulfide formation.
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Affiliation(s)
- Alok Pandey
- From the Department of Pharmacology and Physiology, New Jersey Medical School, Rutgers University, Newark, New Jersey 07101
| | - Donna M. Gordon
- From the Department of Pharmacology and Physiology, New Jersey Medical School, Rutgers University, Newark, New Jersey 07101
| | - Jayashree Pain
- From the Department of Pharmacology and Physiology, New Jersey Medical School, Rutgers University, Newark, New Jersey 07101
| | - Timothy L. Stemmler
- the Department of Pharmaceutical Sciences, Wayne State University, Detroit, Michigan 48201, and
| | - Andrew Dancis
- the Department of Medicine, Division of Hematology-Oncology, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Debkumar Pain
- From the Department of Pharmacology and Physiology, New Jersey Medical School, Rutgers University, Newark, New Jersey 07101
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43
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Ieva R, Heißwolf AK, Gebert M, Vögtle FN, Wollweber F, Mehnert CS, Oeljeklaus S, Warscheid B, Meisinger C, van der Laan M, Pfanner N. Mitochondrial inner membrane protease promotes assembly of presequence translocase by removing a carboxy-terminal targeting sequence. Nat Commun 2013; 4:2853. [DOI: 10.1038/ncomms3853] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2013] [Accepted: 11/01/2013] [Indexed: 01/04/2023] Open
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44
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Farhan SMK, Wang J, Robinson JF, Lahiry P, Siu VM, Prasad C, Kronick JB, Ramsay DA, Rupar CA, Hegele RA. Exome sequencing identifies NFS1 deficiency in a novel Fe-S cluster disease, infantile mitochondrial complex II/III deficiency. Mol Genet Genomic Med 2013; 2:73-80. [PMID: 24498631 PMCID: PMC3907916 DOI: 10.1002/mgg3.46] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Accepted: 10/09/2013] [Indexed: 11/17/2022] Open
Abstract
Iron-sulfur (Fe-S) clusters are a class of highly conserved and ubiquitous prosthetic groups with unique chemical properties that allow the proteins that contain them, Fe-S proteins, to assist in various key biochemical pathways. Mutations in Fe-S proteins often disrupt Fe-S cluster assembly leading to a spectrum of severe disorders such as Friedreich's ataxia or iron-sulfur cluster assembly enzyme (ISCU) myopathy. Herein, we describe infantile mitochondrial complex II/III deficiency, a novel autosomal recessive mitochondrial disease characterized by lactic acidemia, hypotonia, respiratory chain complex II and III deficiency, multisystem organ failure and abnormal mitochondria. Through autozygosity mapping, exome sequencing, in silico analyses, population studies and functional tests, we identified c.215G>A, p.Arg72Gln in NFS1 as the likely causative mutation. We describe the first disease in man likely caused by deficiency in NFS1, a cysteine desulfurase that is implicated in respiratory chain function and iron maintenance by initiating Fe-S cluster biosynthesis. Our results further demonstrate the importance of sufficient NFS1 expression in human physiology.
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Affiliation(s)
- Sali M K Farhan
- Robarts Research Institute, Schulich School of Medicine and Dentistry, Western University London, Ontario, N6A 5K8, Canada ; Department of Biochemistry Schulich School of Medicine and Dentistry, Western University London, Ontario, N6A 5C1, Canada
| | - Jian Wang
- Robarts Research Institute, Schulich School of Medicine and Dentistry, Western University London, Ontario, N6A 5K8, Canada
| | - John F Robinson
- Robarts Research Institute, Schulich School of Medicine and Dentistry, Western University London, Ontario, N6A 5K8, Canada
| | - Piya Lahiry
- Robarts Research Institute, Schulich School of Medicine and Dentistry, Western University London, Ontario, N6A 5K8, Canada
| | - Victoria M Siu
- Department of Biochemistry Schulich School of Medicine and Dentistry, Western University London, Ontario, N6A 5C1, Canada ; Medical Genetics Program Department of Pediatrics, London Health Sciences Centre London, Ontario, N6C 2V5, Canada ; Children's Health Research Institute, London Health Sciences Centre London, Ontario, N6C 2V5, Canada
| | - Chitra Prasad
- Department of Biochemistry Schulich School of Medicine and Dentistry, Western University London, Ontario, N6A 5C1, Canada ; Medical Genetics Program Department of Pediatrics, London Health Sciences Centre London, Ontario, N6C 2V5, Canada ; Children's Health Research Institute, London Health Sciences Centre London, Ontario, N6C 2V5, Canada
| | - Jonathan B Kronick
- Division of Clinical and Metabolic Genetics The Hospital for Sick Children Department of Pediatrics, University of Toronto Toronto, Ontario, M5G 1X8, Canada
| | - David A Ramsay
- Department of Pathology, London Health Sciences Centre London, Ontario, N6A 5A5, Canada
| | - C Anthony Rupar
- Department of Biochemistry Schulich School of Medicine and Dentistry, Western University London, Ontario, N6A 5C1, Canada ; Medical Genetics Program Department of Pediatrics, London Health Sciences Centre London, Ontario, N6C 2V5, Canada ; Children's Health Research Institute, London Health Sciences Centre London, Ontario, N6C 2V5, Canada
| | - Robert A Hegele
- Robarts Research Institute, Schulich School of Medicine and Dentistry, Western University London, Ontario, N6A 5K8, Canada ; Department of Biochemistry Schulich School of Medicine and Dentistry, Western University London, Ontario, N6A 5C1, Canada
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45
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Stames EM, O'Toole JF. Mitochondrial aminopeptidase deletion increases chronological lifespan and oxidative stress resistance while decreasing respiratory metabolism in S. cerevisiae. PLoS One 2013; 8:e77234. [PMID: 24116217 PMCID: PMC3792884 DOI: 10.1371/journal.pone.0077234] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2012] [Accepted: 09/05/2013] [Indexed: 12/15/2022] Open
Abstract
Recessive mutations in XPNPEP3, encoding a mitochondrial x-prolyl aminopeptidase, have been identified in families with a rare hereditary tubulointerstitial kidney disease. The yeast ortholog of XPNPEP3, Icp55p, participates in the proteolytic processing and stabilization of mitochondrial proteins and its deletion accelerates the degradation of its protein targets. We used icp55 deletion strains of S. cerevisiae to model loss of XPNPEP3 enzymatic function and study its phenotypic consequences on mitochondrial function. We found that Icp55p is not required for respiratory competence; however, compared to controls deletion strains had reduced mitochondrial oxygen consumption when grown in glucose containing media. The reduced mitochondrial respiration of icp55 deletion strains in glucose media requires the mitochondrial peptide transporter, Mdl1p, and was corrected by Tor1p inhibition with rapamycin. Under similar growth conditions the abundance of the mitochondrial ATP synthase complex was decreased in the icp55 deletion strain and was corrected by concurrent deletion of tor1. The icp55 deletion strain demonstrated an increased chronological lifespan and decreased reactive oxygen species. These changes were additive to similar changes known to occur in tor1 deletion strains suggesting independent mechanisms. Together, these results demonstrate that loss of Icp55p function reduces mitochondrial oxygen consumption and ATP synthase complex assembly in glucose media, while also promoting stress resistance, decreasing reactive oxygen species and increasing chronological lifespan through mechanisms that are distinct from decreased Tor1p activity.
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Affiliation(s)
- Erine M. Stames
- Department of Medicine, Division of Nephrology MetroHealth Medical System and Case Western Reserve University School of Medicine, Cleveland, Ohio, United States of America
| | - John F. O'Toole
- Department of Medicine, Division of Nephrology MetroHealth Medical System and Case Western Reserve University School of Medicine, Cleveland, Ohio, United States of America
- * E-mail:
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46
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Marelja Z, Mullick Chowdhury M, Dosche C, Hille C, Baumann O, Löhmannsröben HG, Leimkühler S. The L-cysteine desulfurase NFS1 is localized in the cytosol where it provides the sulfur for molybdenum cofactor biosynthesis in humans. PLoS One 2013; 8:e60869. [PMID: 23593335 PMCID: PMC3625234 DOI: 10.1371/journal.pone.0060869] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2013] [Accepted: 03/04/2013] [Indexed: 11/18/2022] Open
Abstract
In humans, the L-cysteine desulfurase NFS1 plays a crucial role in the mitochondrial iron-sulfur cluster biosynthesis and in the thiomodification of mitochondrial and cytosolic tRNAs. We have previously demonstrated that purified NFS1 is able to transfer sulfur to the C-terminal domain of MOCS3, a cytosolic protein involved in molybdenum cofactor biosynthesis and tRNA thiolation. However, no direct evidence existed so far for the interaction of NFS1 and MOCS3 in the cytosol of human cells. Here, we present direct data to show the interaction of NFS1 and MOCS3 in the cytosol of human cells using Förster resonance energy transfer and a split-EGFP system. The colocalization of NFS1 and MOCS3 in the cytosol was confirmed by immunodetection of fractionated cells and localization studies using confocal fluorescence microscopy. Purified NFS1 was used to reconstitute the lacking molybdoenzyme activity of the Neurospora crassa nit-1 mutant, giving additional evidence that NFS1 is the sulfur donor for Moco biosynthesis in eukaryotes in general.
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Affiliation(s)
- Zvonimir Marelja
- Department of Molecular Enzymology, Institute of Biochemistry, University of Potsdam, Potsdam, Germany
| | - Mita Mullick Chowdhury
- Department of Molecular Enzymology, Institute of Biochemistry, University of Potsdam, Potsdam, Germany
| | - Carsten Dosche
- Department of Physical Chemistry, Institute of Chemistry, University of Potsdam, Potsdam, Germany
| | - Carsten Hille
- Department of Physical Chemistry, Institute of Chemistry, University of Potsdam, Potsdam, Germany
| | - Otto Baumann
- Department of Animal Physiology, Institute of Biochemistry, University of Potsdam, Potsdam, Germany
| | - Hans-Gerd Löhmannsröben
- Department of Physical Chemistry, Institute of Chemistry, University of Potsdam, Potsdam, Germany
| | - Silke Leimkühler
- Department of Molecular Enzymology, Institute of Biochemistry, University of Potsdam, Potsdam, Germany
- * E-mail:
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47
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Lionaki E, Tavernarakis N. Oxidative stress and mitochondrial protein quality control in aging. J Proteomics 2013; 92:181-94. [PMID: 23563202 DOI: 10.1016/j.jprot.2013.03.022] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2013] [Revised: 02/22/2013] [Accepted: 03/25/2013] [Indexed: 12/17/2022]
Abstract
Mitochondrial protein quality control incorporates an elaborate network of chaperones and proteases that survey the organelle for misfolded or unfolded proteins and toxic aggregates. Repair of misfolded or aggregated protein and proteolytic removal of irreversibly damaged proteins are carried out by the mitochondrial protein quality control system. Initial maturation and folding of the nuclear or mitochondrial-encoded mitochondrial proteins are mediated by processing peptidases and chaperones that interact with the protein translocation machinery. Mitochondrial proteins are subjected to cumulative oxidative damage. Thus, impairment of quality control processes may cause mitochondrial dysfunction. Aging has been associated with a marked decline in the effectiveness of mitochondrial protein quality control. Here, we present an overview of the chaperones and proteases involved in the initial folding and maturation of new, incoming precursor molecules, and the subsequent repair and removal of oxidized aggregated proteins. In addition, we highlight the link between mitochondrial protein quality control mechanisms and the aging process. This article is part of a Special Issue entitled: Posttranslational Protein modifications in biology and Medicine.
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Affiliation(s)
- Eirini Lionaki
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion 71110, Crete, Greece
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48
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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.
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Affiliation(s)
- Efrat Burak
- Department of Microbiology Molecular Genetics, IMRIC, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
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49
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Voos W, Ward LA, Truscott KN. The role of AAA+ proteases in mitochondrial protein biogenesis, homeostasis and activity control. Subcell Biochem 2013; 66:223-263. [PMID: 23479443 DOI: 10.1007/978-94-007-5940-4_9] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Mitochondria are specialised organelles that are structurally and functionally integrated into cells in the vast majority of eukaryotes. They are the site of numerous enzymatic reactions, some of which are essential for life. The double lipid membrane of the mitochondrion, that spatially defines the organelle and is necessary for some functions, also creates a physical but semi-permeable barrier to the rest of the cell. Thus to ensure the biogenesis, regulation and maintenance of a functional population of proteins, an autonomous protein handling network within mitochondria is required. This includes resident mitochondrial protein translocation machinery, processing peptidases, molecular chaperones and proteases. This review highlights the contribution of proteases of the AAA+ superfamily to protein quality and activity control within the mitochondrion. Here they are responsible for the degradation of unfolded, unassembled and oxidatively damaged proteins as well as the activity control of some enzymes. Since most knowledge about these proteases has been gained from studies in the eukaryotic microorganism Saccharomyces cerevisiae, much of the discussion here centres on their role in this organism. However, reference is made to mitochondrial AAA+ proteases in other organisms, particularly in cases where they play a unique role such as the mitochondrial unfolded protein response. As these proteases influence mitochondrial function in both health and disease in humans, an understanding of their regulation and diverse activities is necessary.
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Affiliation(s)
- Wolfgang Voos
- Institut für Biochemie und Molekularbiologie (IBMB), Universität Bonn, Nussallee 11, 53115, Bonn, Germany,
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50
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Mach J, Poliak P, Matušková A, Žárský V, Janata J, Lukeš J, Tachezy J. An Advanced System of the Mitochondrial Processing Peptidase and Core Protein Family in Trypanosoma brucei and Multiple Origins of the Core I Subunit in Eukaryotes. Genome Biol Evol 2013; 5:860-75. [PMID: 23563972 PMCID: PMC3673636 DOI: 10.1093/gbe/evt056] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/02/2013] [Indexed: 01/20/2023] Open
Abstract
Mitochondrial processing peptidase (MPP) consists of α and β subunits that catalyze the cleavage of N-terminal mitochondrial-targeting sequences (N-MTSs) and deliver preproteins to the mitochondria. In plants, both MPP subunits are associated with the respiratory complex bc1, which has been proposed to represent an ancestral form. Subsequent duplication of MPP subunits resulted in separate sets of genes encoding soluble MPP in the matrix and core proteins (cp1 and cp2) of the membrane-embedded bc1 complex. As only α-MPP was duplicated in Neurospora, its single β-MPP functions in both MPP and bc1 complexes. Herein, we investigated the MPP/core protein family and N-MTSs in the kinetoplastid Trypanosoma brucei, which is often considered one of the most ancient eukaryotes. Analysis of N-MTSs predicted in 336 mitochondrial proteins showed that trypanosomal N-MTSs were comparable with N-MTSs from other organisms. N-MTS cleavage is mediated by a standard heterodimeric MPP, which is present in the matrix of procyclic and bloodstream trypanosomes, and its expression is essential for the parasite. Distinct Genes encode cp1 and cp2, and in the bloodstream forms the expression of cp1 is downregulated along with the bc1 complex. Phylogenetic analysis revealed that all eukaryotic lineages include members with a Neurospora-type MPP/core protein family, whereas cp1 evolved independently in metazoans, some fungi and kinetoplastids. Evolution of cp1 allowed the independent regulation of respiration and protein import, which is essential for the procyclic and bloodstream forms of T. brucei. These results indicate that T. brucei possesses a highly derived MPP/core protein family that likely evolved in response to its complex life cycle and does not appear to have an ancient character proposed earlier for this eukaryote.
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Affiliation(s)
- Jan Mach
- Department of Parasitology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Pavel Poliak
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Prague, Czech Republic
- Faculty of Science, University of South Bohemia, České Budějovice, Budweis, Czech Republic
| | - Anna Matušková
- Institute of Microbiology, Czech Academy of Sciences, Prague, Czech Republic
| | - Vojtěch Žárský
- Department of Parasitology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Jiří Janata
- Institute of Microbiology, Czech Academy of Sciences, Prague, Czech Republic
| | - Julius Lukeš
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Prague, Czech Republic
- Faculty of Science, University of South Bohemia, České Budějovice, Budweis, Czech Republic
| | - Jan Tachezy
- Department of Parasitology, Faculty of Science, Charles University, Prague, Czech Republic
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