251
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Shikha S, Huot JL, Schneider A, Niemann M. tRNA import across the mitochondrial inner membrane in T. brucei requires TIM subunits but is independent of protein import. Nucleic Acids Res 2020; 48:12269-12281. [PMID: 33231678 PMCID: PMC7708065 DOI: 10.1093/nar/gkaa1098] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 10/20/2020] [Accepted: 11/03/2020] [Indexed: 01/27/2023] Open
Abstract
Mitochondrial tRNA import is widespread, but mechanistic insights of how tRNAs are translocated across mitochondrial membranes remain scarce. The parasitic protozoan T. brucei lacks mitochondrial tRNA genes. Consequently, it imports all organellar tRNAs from the cytosol. Here we investigated the connection between tRNA and protein translocation across the mitochondrial inner membrane. Trypanosomes have a single inner membrane protein translocase that consists of three heterooligomeric submodules, which all are required for import of matrix proteins. In vivo depletion of individual submodules shows that surprisingly only the integral membrane core module, including the protein import pore, but not the presequence-associated import motor are required for mitochondrial tRNA import. Thus we could uncouple import of matrix proteins from import of tRNAs even though both substrates are imported into the same mitochondrial subcompartment. This is reminiscent to the outer membrane where the main protein translocase but not on-going protein translocation is required for tRNA import. We also show that import of tRNAs across the outer and inner membranes are coupled to each other. Taken together, these data support the 'alternate import model', which states that tRNA and protein import while mechanistically independent use the same translocation pores but not at the same time.
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Affiliation(s)
- Shikha Shikha
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, 3012 Bern, Switzerland
| | - Jonathan L Huot
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, 3012 Bern, Switzerland
| | - André Schneider
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, 3012 Bern, Switzerland
| | - Moritz Niemann
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, 3012 Bern, Switzerland
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252
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Lesmana R, Felia Yusuf I, Goenawan H, Achadiyani A, Khairani AF, Nur Fatimah S, Supratman U. Low Dose of β-Carotene Regulates Inflammation, Reduces Caspase Signaling, and Correlates with Autophagy Activation in Cardiomyoblast Cell Lines. Med Sci Monit Basic Res 2020; 26:e928648. [PMID: 33361744 PMCID: PMC7780889 DOI: 10.12659/msmbr.928648] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Background Excessive reactive oxygen species (ROS) stimulate mitochondrial damage that causes degenerative diseases such as cardiovascular disease (CVD). β-carotene (BC), a natural antioxidant able to counteract free radicals, acts as a cytoprotective agent. However, knowledge of the role of BC on cardiomyoblasts is limited. In this study, we explored its role on COX4, Tom20, Nfr1, Nrf2, Nf-κB, LC3, p62, caspase 3, and caspase 9 and its association with cardiomyoblast viability and survival. Material/Methods H9C2 cell lines were seeded, cultivated until 90% to 100% confluency, and treated with various doses of BC: 10 μM, 1 μM, 0.1 μM, and 0.01 μM. After 24 h, the cells were harvested, lyzed, and tested for specific related protein expressions from each dose. Results Low-dose BC induced autophagy most effectively at 1 μM, 0.1 μM, and 0.01 μM, as indicated by a decrease of LC3II and p62 levels. We observed that Nf-κB protein levels were suppressed; Nrf2 was stimulated, but Nrf1 was not altered significantly. Further, low-dose BC might stimulate cell viability by reducing apoptotic signals of caspase 3 and 9. Notably, low-dose BC also showed potential to increase Tom20 protein levels. Conclusions Low-dose BC supplementation shows beneficial effects, especially at 0.01 μM, by reducing inflammation through the suppression of Nf-κB and increase of Nrf2 level. Autophagy as a cellular maintenance mechanism was also stimulated, and the amount of the mitochondria marker Tom20 increased. Taken together, results showed that specific low-dose BC is effective and might improve cell viability by stimulating autophagy, inhibiting proinflammatory factors, and suppressing apoptosis.
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Affiliation(s)
- Ronny Lesmana
- Physiology Division, Department of Biomedical Science, Faculty of Medicine, University Padjadjaran, Jatinangor, Indonesia.,Division of Biological Activity, Central Laboratory, University Padjadjaran, Bandung, Indonesia.,Center of Excellence in Higher Education for Pharmaceutical Care Innovation, University Padjadjaran, Bandung, Indonesia
| | - Inez Felia Yusuf
- Postgraduate Program of Anti-Aging and Aesthetics Medicine, Faculty of Medicine, University Padjadjaran, Bandung, Indonesia
| | - Hanna Goenawan
- Physiology Division, Department of Biomedical Science, Faculty of Medicine, University Padjadjaran, Bandung, Indonesia.,Division of Biological Activity, Central Laboratory, University Padjadjaran, Bandung, Indonesia
| | - Achadiyani Achadiyani
- Cell Biology Division, Department of Biomedical Science, Faculty of Medicine, University Padjadjaran, Jatinangor, Indonesia
| | - Astrid Feinisa Khairani
- Postgraduate Program of Anti-Aging and Aesthetics Medicine, Faculty of Medicine, University Padjadjaran, Bandung, Indonesia.,Cell Biology Division, Department of Biomedical Science, Faculty of Medicine, University Padjadjaran, Jatinangor, Indonesia
| | - Siti Nur Fatimah
- Department of Medical Nutrition, Faculty of Medicine, University Padjadjaran, Bandung, Indonesia
| | - Unang Supratman
- Department of Chemistry, Faculty of Mathematics and Natural Sciences, University Padjadjaran, Bandung, Indonesia
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253
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Corum DG, Jenkins DP, Heslop JA, Tallent LM, Beeson GC, Barth JL, Schnellmann RG, Muise-Helmericks RC. PDE5 inhibition rescues mitochondrial dysfunction and angiogenic responses induced by Akt3 inhibition by promotion of PRC expression. J Biol Chem 2020; 295:18091-18104. [PMID: 33087445 PMCID: PMC7939459 DOI: 10.1074/jbc.ra120.013716] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2020] [Revised: 10/15/2020] [Indexed: 12/01/2022] Open
Abstract
Akt3 regulates mitochondrial content in endothelial cells through the inhibition of PGC-1α nuclear localization and is also required for angiogenesis. However, whether there is a direct link between mitochondrial function and angiogenesis is unknown. Here we show that Akt3 depletion in primary endothelial cells results in decreased uncoupled oxygen consumption, increased fission, decreased membrane potential, and increased expression of the mitochondria-specific protein chaperones, HSP60 and HSP10, suggesting that Akt3 is required for mitochondrial homeostasis. Direct inhibition of mitochondrial homeostasis by the model oxidant paraquat results in decreased angiogenesis, showing a direct link between angiogenesis and mitochondrial function. Next, in exploring functional links to PGC-1α, the master regulator of mitochondrial biogenesis, we searched for compounds that induce this process. We found that, sildenafil, a phosphodiesterase 5 inhibitor, induced mitochondrial biogenesis as measured by increased uncoupled oxygen consumption, mitochondrial DNA content, and voltage-dependent anion channel protein expression. Sildenafil rescued the effects on mitochondria by Akt3 depletion or pharmacological inhibition and promoted angiogenesis, further supporting that mitochondrial homeostasis is required for angiogenesis. Sildenafil also induces the expression of PGC-1 family member PRC and can compensate for PGC-1α activity during mitochondrial stress by an Akt3-independent mechanism. The induction of PRC by sildenafil depends upon cAMP and the transcription factor CREB. Thus, PRC can functionally substitute during Akt3 depletion for absent PGC-1α activity to restore mitochondrial homeostasis and promote angiogenesis. These findings show that mitochondrial homeostasis as controlled by the PGC family of transcriptional activators is required for angiogenic responses.
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Affiliation(s)
- Daniel G Corum
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, South Carolina
| | - Dorea P Jenkins
- Department of Pathology, Medical University of South Carolina, Charleston, South Carolina
| | - James A Heslop
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, South Carolina
| | - Lacey M Tallent
- Department of Bioengineering, Duke University, Durham, North Carolina
| | - Gyda C Beeson
- Department of Drug Discovery, Medical University of South Carolina, Charleston, South Carolina
| | - Jeremy L Barth
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, South Carolina
| | | | - Robin C Muise-Helmericks
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, South Carolina.
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254
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Moro L. The Mitochondrial Proteome of Tumor Cells: A SnapShot on Methodological Approaches and New Biomarkers. BIOLOGY 2020; 9:biology9120479. [PMID: 33353059 PMCID: PMC7766083 DOI: 10.3390/biology9120479] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 12/12/2020] [Accepted: 12/16/2020] [Indexed: 12/12/2022]
Abstract
Simple Summary Mitochondria are central hubs of cellular signaling, energy metabolism, and redox balance. The plasticity of these cellular organelles is an essential requisite for the cells to cope with different stimuli and stress conditions. Cancer cells are characterized by changes in energy metabolism, mitochondrial signaling, and dynamics. These changes are driven by alterations in the mitochondrial proteome. For this reason, in the last years a focus of basic and cancer research has been the implementation and optimization of technologies to investigate changes in the mitochondrial proteome during cancer initiation and progression. This review presents an overview of the most used technologies to investigate the mitochondrial proteome and recent evidence on changes in the expression levels and delocalization of certain proteins in and out the mitochondria for shaping the functional properties of tumor cells. Abstract Mitochondria are highly dynamic and regulated organelles implicated in a variety of important functions in the cell, including energy production, fatty acid metabolism, iron homeostasis, programmed cell death, and cell signaling. Changes in mitochondrial metabolism, signaling and dynamics are hallmarks of cancer. Understanding whether these modifications are associated with alterations of the mitochondrial proteome is particularly relevant from a translational point of view because it may contribute to better understanding the molecular bases of cancer development and progression and may provide new potential prognostic and diagnostic biomarkers as well as novel molecular targets for anti-cancer treatment. Making an inventory of the mitochondrial proteins has been particularly challenging given that there is no unique consensus targeting sequence that directs protein import into mitochondria, some proteins are present at very low levels, while other proteins are expressed only in some cell types, in a particular developmental stage or under specific stress conditions. This review aims at providing the state-of-the-art on methodologies used to characterize the mitochondrial proteome in tumors and highlighting the biological relevance of changes in expression and delocalization of proteins in and out the mitochondria in cancer biology.
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Affiliation(s)
- Loredana Moro
- Institute of Biomembranes, Bioenergetic and Molecular Biotechnologies, National Research Council, Via Amendola 122/O, 70125 Bari, Italy
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255
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Fernandez-Vizarra E, Zeviani M. Mitochondrial disorders of the OXPHOS system. FEBS Lett 2020; 595:1062-1106. [PMID: 33159691 DOI: 10.1002/1873-3468.13995] [Citation(s) in RCA: 109] [Impact Index Per Article: 27.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2020] [Revised: 10/21/2020] [Accepted: 11/01/2020] [Indexed: 12/13/2022]
Abstract
Mitochondrial disorders are among the most frequent inborn errors of metabolism, their primary cause being the dysfunction of the oxidative phosphorylation system (OXPHOS). OXPHOS is composed of the electron transport chain (ETC), formed by four multimeric enzymes and two mobile electron carriers, plus an ATP synthase [also called complex V (cV)]. The ETC performs the redox reactions involved in cellular respiration while generating the proton motive force used by cV to synthesize ATP. OXPHOS biogenesis involves multiple steps, starting from the expression of genes encoded in physically separated genomes, namely the mitochondrial and nuclear DNA, to the coordinated assembly of components and cofactors building each individual complex and eventually the supercomplexes. The genetic cause underlying around half of the diagnosed mitochondrial disease cases is currently known. Many of these cases result from pathogenic variants in genes encoding structural subunits or additional factors directly involved in the assembly of the ETC complexes. Here, we review the historical and most recent findings concerning the clinical phenotypes and the molecular pathological mechanisms underlying this particular group of disorders.
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Affiliation(s)
- Erika Fernandez-Vizarra
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, UK
| | - Massimo Zeviani
- Venetian Institute of Molecular Medicine, Padova, Italy.,Department of Neurosciences, University of Padova, Italy
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256
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Urushima Y, Haraguchi M, Yano M. Depletion of TMEM65 leads to oxidative stress, apoptosis, induction of mitochondrial unfolded protein response, and upregulation of mitochondrial protein import receptor TOMM22. Biochem Biophys Rep 2020; 24:100870. [PMID: 33319071 PMCID: PMC7725676 DOI: 10.1016/j.bbrep.2020.100870] [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: 07/20/2020] [Revised: 11/12/2020] [Accepted: 11/27/2020] [Indexed: 10/24/2022] Open
Abstract
Mutation in the transmembrane protein 65 gene (TMEM65) results in mitochondrial dysfunction and a severe mitochondrial encephalomyopathy phenotype. However, neither the function of TMEM65 nor the cellular responses to its depletion have been fully elucidated. Hence, we knocked down TMEM65 in human cultured cells and analyzed the resulting cellular responses. Depletion of TMEM65 led to a mild increase in ROS generation and upregulation of the mRNA levels of oxidative stress suppressors, such as NFE2L2 and SESN3, indicating that TMEM65 knockdown induced an oxidative stress response. A mild induction of apoptosis was also observed upon depletion of TMEM65. Depletion of TMEM65 upregulated protein levels of the mitochondrial chaperone HSPD1 and mitochondrial protease LONP1, indicating that mitochondrial unfolded protein response (UPRmt) was induced in response to TMEM65 depletion. Additionally, we found that the mitochondrial protein import receptor TOMM22 and HSPA9 (mitochondrial Hsp70), were also upregulated in TMEM65-depleted cells. Notably, the depletion of TMEM65 did not lead to upregulation of TOMM22 in an ATF5-dependent manner, although upregulation of LONP1 reportedly occurs in an ATF5-dependent manner. Taken together, our findings suggest that depletion of TMEM65 causes mild oxidative stress and apoptosis, induces UPRmt, and upregulates protein expression of mitochondrial protein import receptor TOMM22 in an ATF5-independent manner.
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Affiliation(s)
- Yuto Urushima
- Department of Medical Technology, Faculty of Health Sciences, Kumamoto Health Science University, Kumamoto, 861-5598, Japan
| | - Misa Haraguchi
- Department of Medical Technology, Faculty of Health Sciences, Kumamoto Health Science University, Kumamoto, 861-5598, Japan
| | - Masato Yano
- Department of Medical Technology, Faculty of Health Sciences, Kumamoto Health Science University, Kumamoto, 861-5598, Japan
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257
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Krämer L, Groh C, Herrmann JM. The proteasome: friend and foe of mitochondrial biogenesis. FEBS Lett 2020; 595:1223-1238. [PMID: 33249599 DOI: 10.1002/1873-3468.14010] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 10/26/2020] [Accepted: 11/01/2020] [Indexed: 01/06/2023]
Abstract
Most mitochondrial proteins are synthesized in the cytosol and subsequently translocated as unfolded polypeptides into mitochondria. Cytosolic chaperones maintain precursor proteins in an import-competent state. This post-translational import reaction is under surveillance of the cytosolic ubiquitin-proteasome system, which carries out several distinguishable activities. On the one hand, the proteasome degrades nonproductive protein precursors from the cytosol and nucleus, import intermediates that are stuck in mitochondrial translocases, and misfolded or damaged proteins from the outer membrane and the intermembrane space. These surveillance activities of the proteasome are essential for mitochondrial functionality, as well as cellular fitness and survival. On the other hand, the proteasome competes with mitochondria for nonimported cytosolic precursor proteins, which can compromise mitochondrial biogenesis. In order to balance the positive and negative effects of the cytosolic protein quality control system on mitochondria, mitochondrial import efficiency directly regulates the capacity of the proteasome via transcription factor Rpn4 in yeast and nuclear respiratory factor (Nrf) 1 and 2 in animal cells. In this review, we provide a thorough overview of how the proteasome regulates mitochondrial biogenesis.
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Affiliation(s)
- Lena Krämer
- Cell Biology, University of Kaiserslautern, Germany
| | - Carina Groh
- Cell Biology, University of Kaiserslautern, Germany
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258
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Kang J, Zhou H, Sun F, Chen Y, Zhao J, Yang WJ, Xu S, Chen C. Caenorhabditis elegans homologue of Fam210 is required for oogenesis and reproduction. J Genet Genomics 2020; 47:694-704. [PMID: 33547005 DOI: 10.1016/j.jgg.2020.10.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 09/11/2020] [Accepted: 10/16/2020] [Indexed: 11/30/2022]
Abstract
Mitochondria are the central hub for many metabolic processes, including the citric acid cycle, oxidative phosphorylation, and fatty acid oxidation. Recent studies have identified a new mitochondrial protein family, Fam210, that regulates bone metabolism and red cell development in vertebrates. The model organism Caenorhabditis elegans has a Fam210 gene, y56a3a.22, but it lacks both bones and red blood cells. In this study, we report that Y56A3A.22 plays a crucial role in regulating mitochondrial protein homeostasis and reproduction. The nematode y56a3a.22 is expressed in various tissues, including the intestine, muscle, hypodermis, and germline, and its encoded protein is predominantly localized in mitochondria. y56a3a.22 deletion mutants are sterile owing to impaired oogenesis. Loss of Y56A3A.22 induced mitochondrial unfolded protein response (UPRmt), which is mediated through the ATFS-1-dependent pathway, in tissues such as the intestine, germline, hypodermis, and vulval muscle. We further show that infertility and UPRmt induces by Y56A3A.22 deficiency are not attributed to systemic iron deficiency. Together, our study reveals an important role of Y56A3A.22 in regulating mitochondrial protein homeostasis and oogenesis and provides a new genetic tool for exploring the mechanisms regulating mitochondrial metabolism and reproduction as well as the fundamental role of the Fam210 family.
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Affiliation(s)
- Jing Kang
- MOE Key Laboratory of Biosystems Homeostasis and Protection, College of Life Sciences, Zhejiang University, Hangzhou 310058, China
| | - Hengda Zhou
- Center for Stem Cell and Regenerative Medicine and Department of Cardiology of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Fengxiu Sun
- MOE Key Laboratory of Biosystems Homeostasis and Protection, College of Life Sciences, Zhejiang University, Hangzhou 310058, China
| | - Yongtian Chen
- MOE Key Laboratory of Biosystems Homeostasis and Protection, College of Life Sciences, Zhejiang University, Hangzhou 310058, China
| | - Jianzhi Zhao
- Center for Stem Cell and Regenerative Medicine and Department of Cardiology of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Wei-Jun Yang
- MOE Key Laboratory of Biosystems Homeostasis and Protection, College of Life Sciences, Zhejiang University, Hangzhou 310058, China
| | - Suhong Xu
- Center for Stem Cell and Regenerative Medicine and Department of Cardiology of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Caiyong Chen
- MOE Key Laboratory of Biosystems Homeostasis and Protection, College of Life Sciences, Zhejiang University, Hangzhou 310058, China.
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259
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Shao F, Lyu X, Miao K, Xie L, Wang H, Xiao H, Li J, Chen Q, Ding R, Chen P, Xing F, Zhang X, Luo G, Zhu W, Cheng G, Lon NW, Martin SE, Wang G, Chen G, Dai Y, Deng C. Enhanced Protein Damage Clearance Induces Broad Drug Resistance in Multitype of Cancers Revealed by an Evolution Drug-Resistant Model and Genome-Wide siRNA Screening. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2020; 7:2001914. [PMID: 33304752 PMCID: PMC7709997 DOI: 10.1002/advs.202001914] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 08/09/2020] [Indexed: 05/08/2023]
Abstract
Resistance to therapeutic drugs occurs in virtually all types of cancers, and the tolerance to one drug frequently becomes broad therapy resistance; however, the underlying mechanism remains elusive. Combining a whole whole-genome-wide RNA interference screening and an evolutionary drug pressure model with MDA-MB-231 cells, it is found that enhanced protein damage clearance and reduced mitochondrial respiratory activity are responsible for cisplatin resistance. Screening drug-resistant cancer cells and human patient-derived organoids for breast and colon cancers with many anticancer drugs indicates that activation of mitochondrion protein import surveillance system enhances proteasome activity and minimizes caspase activation, leading to broad drug resistance that can be overcome by co-treatment with a proteasome inhibitor, bortezomib. It is further demonstrated that cisplatin and bortezomib encapsulated into nanoparticle further enhance their therapeutic efficacy and alleviate side effects induced by drug combination treatment. These data demonstrate a feasibility for eliminating broad drug resistance by targeting its common mechanism to achieve effective therapy for multiple cancers.
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Affiliation(s)
- Fangyuan Shao
- Cancer CenterFaculty of Health SciencesUniversity of MacauMacau999078China
- Center for Precision Medicine Research and TrainingFaculty of Health SciencesUniversity of MacauMacau999078China
| | - Xueying Lyu
- Cancer CenterFaculty of Health SciencesUniversity of MacauMacau999078China
- Center for Precision Medicine Research and TrainingFaculty of Health SciencesUniversity of MacauMacau999078China
| | - Kai Miao
- Cancer CenterFaculty of Health SciencesUniversity of MacauMacau999078China
- Center for Precision Medicine Research and TrainingFaculty of Health SciencesUniversity of MacauMacau999078China
| | - Lisi Xie
- Cancer CenterFaculty of Health SciencesUniversity of MacauMacau999078China
| | - Haitao Wang
- Cancer CenterFaculty of Health SciencesUniversity of MacauMacau999078China
| | - Hao Xiao
- Guangdong Key Laboratory of Animal Breeding and NutritionInstitute of Animal ScienceGuangdong Academy of Agricultural SciencesGuangzhou510640China
| | - Jie Li
- Cancer CenterFaculty of Health SciencesUniversity of MacauMacau999078China
- Center for Precision Medicine Research and TrainingFaculty of Health SciencesUniversity of MacauMacau999078China
| | - Qiang Chen
- Cancer CenterFaculty of Health SciencesUniversity of MacauMacau999078China
- Center for Precision Medicine Research and TrainingFaculty of Health SciencesUniversity of MacauMacau999078China
| | - Renbo Ding
- Cancer CenterFaculty of Health SciencesUniversity of MacauMacau999078China
- Center for Precision Medicine Research and TrainingFaculty of Health SciencesUniversity of MacauMacau999078China
| | - Ping Chen
- Cancer CenterFaculty of Health SciencesUniversity of MacauMacau999078China
- Center for Precision Medicine Research and TrainingFaculty of Health SciencesUniversity of MacauMacau999078China
| | - Fuqiang Xing
- Cancer CenterFaculty of Health SciencesUniversity of MacauMacau999078China
- Department of BiologySouthern University of Science and TechnologyShenzhen518055China
| | - Xu Zhang
- Cancer CenterFaculty of Health SciencesUniversity of MacauMacau999078China
- Center for Precision Medicine Research and TrainingFaculty of Health SciencesUniversity of MacauMacau999078China
| | | | | | - Gregory Cheng
- Cancer CenterFaculty of Health SciencesUniversity of MacauMacau999078China
| | - Ng Wai Lon
- Centro Hospitalar Conde de S. JanuárioMacau820004China
| | - Scott E. Martin
- Division of Pre‐Clinical InnovationNational Center for Advancing Translational Sciences (NCATS)National Institutes of HealthBethesdaMD20892USA
| | - Guanyu Wang
- Department of BiologySouthern University of Science and TechnologyShenzhen518055China
| | - Guokai Chen
- Cancer CenterFaculty of Health SciencesUniversity of MacauMacau999078China
- Center for Precision Medicine Research and TrainingFaculty of Health SciencesUniversity of MacauMacau999078China
| | - Yunlu Dai
- Cancer CenterFaculty of Health SciencesUniversity of MacauMacau999078China
- Center for Precision Medicine Research and TrainingFaculty of Health SciencesUniversity of MacauMacau999078China
| | - Chu‐Xia Deng
- Cancer CenterFaculty of Health SciencesUniversity of MacauMacau999078China
- Center for Precision Medicine Research and TrainingFaculty of Health SciencesUniversity of MacauMacau999078China
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260
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Imai K, Nakai K. Tools for the Recognition of Sorting Signals and the Prediction of Subcellular Localization of Proteins From Their Amino Acid Sequences. Front Genet 2020; 11:607812. [PMID: 33324450 PMCID: PMC7723863 DOI: 10.3389/fgene.2020.607812] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Accepted: 11/03/2020] [Indexed: 12/13/2022] Open
Abstract
At the time of translation, nascent proteins are thought to be sorted into their final subcellular localization sites, based on the part of their amino acid sequences (i.e., sorting or targeting signals). Thus, it is interesting to computationally recognize these signals from the amino acid sequences of any given proteins and to predict their final subcellular localization with such information, supplemented with additional information (e.g., k-mer frequency). This field has a long history and many prediction tools have been released. Even in this era of proteomic atlas at the single-cell level, researchers continue to develop new algorithms, aiming at accessing the impact of disease-causing mutations/cell type-specific alternative splicing, for example. In this article, we overview the entire field and discuss its future direction.
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Affiliation(s)
- Kenichiro Imai
- Cellular and Molecular Biotechnology Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tokyo, Japan
| | - Kenta Nakai
- The Institute of Medical Science, The University of Tokyo, Tokyo, Japan
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261
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Saragovi A, Abramovich I, Omar I, Arbib E, Toker O, Gottlieb E, Berger M. Systemic hypoxia inhibits T cell response by limiting mitobiogenesis via matrix substrate-level phosphorylation arrest. eLife 2020; 9:56612. [PMID: 33226340 PMCID: PMC7728436 DOI: 10.7554/elife.56612] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Accepted: 11/21/2020] [Indexed: 11/30/2022] Open
Abstract
Systemic oxygen restriction (SOR) is prevalent in numerous clinical conditions, including chronic obstructive pulmonary disease (COPD), and is associated with increased susceptibility to viral infections. However, the influence of SOR on T cell immunity remains uncharacterized. Here we show the detrimental effect of hypoxia on mitochondrial-biogenesis in activated mouse CD8+ T cells. We find that low oxygen level diminishes CD8+ T cell anti-viral response in vivo. We reveal that respiratory restriction inhibits ATP-dependent matrix processes that are critical for mitochondrial-biogenesis. This respiratory restriction-mediated effect could be rescued by TCA cycle re-stimulation, which yielded increased mitochondrial matrix-localized ATP via substrate-level phosphorylation. Finally, we demonstrate that the hypoxia-arrested CD8+ T cell anti-viral response could be rescued in vivo through brief exposure to atmospheric oxygen pressure. Overall, these findings elucidate the detrimental effect of hypoxia on mitochondrial-biogenesis in activated CD8+ T cells, and suggest a new approach for reducing viral infections in COPD.
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Affiliation(s)
- Amijai Saragovi
- The Lautenberg center for Immunology and Cancer Research, The Institute for Medical Research Israel-Canada, The Hebrew University Medical School, Jerusalem, Israel
| | - Ifat Abramovich
- The Ruth and Bruce Rappaport, Faculty of Medicine, Technion - Israel Institute of Technology, Jerusalem, Israel
| | - Ibrahim Omar
- The Lautenberg center for Immunology and Cancer Research, The Institute for Medical Research Israel-Canada, The Hebrew University Medical School, Jerusalem, Israel
| | - Eliran Arbib
- The Lautenberg center for Immunology and Cancer Research, The Institute for Medical Research Israel-Canada, The Hebrew University Medical School, Jerusalem, Israel
| | - Ori Toker
- Faculty of Medicine, Hebrew University of Jerusalem; The Allergy and Immunology Unit, Shaare Zedek Medical Center, Jerusalem, Israel
| | - Eyal Gottlieb
- The Ruth and Bruce Rappaport, Faculty of Medicine, Technion - Israel Institute of Technology, Jerusalem, Israel
| | - Michael Berger
- The Lautenberg center for Immunology and Cancer Research, The Institute for Medical Research Israel-Canada, The Hebrew University Medical School, Jerusalem, Israel
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262
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Foret MK, Lincoln R, Do Carmo S, Cuello AC, Cosa G. Connecting the "Dots": From Free Radical Lipid Autoxidation to Cell Pathology and Disease. Chem Rev 2020; 120:12757-12787. [PMID: 33211489 DOI: 10.1021/acs.chemrev.0c00761] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Our understanding of lipid peroxidation in biology and medicine is rapidly evolving, as it is increasingly implicated in various diseases but also recognized as a key part of normal cell function, signaling, and death (ferroptosis). Not surprisingly, the root and consequences of lipid peroxidation have garnered increasing attention from multiple disciplines in recent years. Here we "connect the dots" between the fundamental chemistry underpinning the cascade reactions of lipid peroxidation (enzymatic or free radical), the reactive nature of the products formed (lipid-derived electrophiles), and the biological targets and mechanisms associated with these products that culminate in cellular responses. We additionally bring light to the use of highly sensitive, fluorescence-based methodologies. Stemming from the foundational concepts in chemistry and biology, these methodologies enable visualizing and quantifying each reaction in the cascade in a cellular and ultimately tissue context, toward deciphering the connections between the chemistry and physiology of lipid peroxidation. The review offers a platform in which the chemistry and biomedical research communities can access a comprehensive summary of fundamental concepts regarding lipid peroxidation, experimental tools for the study of such processes, as well as the recent discoveries by leading investigators with an emphasis on significant open questions.
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Affiliation(s)
- Morgan K Foret
- Department of Pharmacology and Therapeutics, McGill University, 3655 Promenade Sir William Osler, Montreal, Quebec, Canada H3G 1Y6
| | - Richard Lincoln
- Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, Quebec, Canada H3A 0B8
| | - Sonia Do Carmo
- Department of Pharmacology and Therapeutics, McGill University, 3655 Promenade Sir William Osler, Montreal, Quebec, Canada H3G 1Y6
| | - A Claudio Cuello
- Department of Pharmacology and Therapeutics, McGill University, 3655 Promenade Sir William Osler, Montreal, Quebec, Canada H3G 1Y6.,Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec, Canada H3A 0C7.,Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec, Canada H3A 2B4
| | - Gonzalo Cosa
- Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, Quebec, Canada H3A 0B8
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263
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Sulkshane P, Ram J, Glickman MH. Ubiquitination of Intramitochondrial Proteins: Implications for Metabolic Adaptability. Biomolecules 2020; 10:biom10111559. [PMID: 33207558 PMCID: PMC7697252 DOI: 10.3390/biom10111559] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2020] [Revised: 11/11/2020] [Accepted: 11/12/2020] [Indexed: 02/07/2023] Open
Abstract
Mitochondria are constantly subjected to stressful conditions due to their unique physiology and organization. The resulting damage leads to mitochondrial dysfunction, which underlies many pathophysiological conditions. Hence, constant surveillance is required to closely monitor mitochondrial health for sound maintenance of cellular metabolism and thus, for viability. In addition to internal mitochondrial chaperones and proteases, mitochondrial health is also governed by host cell protein quality control systems. The ubiquitin-proteasome system (UPS) and autophagy constitute the main pathways for removal of damaged or superfluous proteins in the cytosol, nucleus, and from certain organelles such as the Endoplasmic Reticulum (ER) and mitochondria. Although stress-induced ubiquitin-dependent degradation of mitochondrial outer membrane proteins has been widely studied, mechanisms of intramitochondrial protein ubiquitination has remained largely elusive due to the predominantly cytosolic nature of UPS components, separated from internal mitochondrial proteins by a double membrane. However, recent research has illuminated examples of intramitochondrial protein ubiquitination pathways and highlighted their importance under basal and stressful conditions. Owing to the dependence of mitochondria on the error-prone process of protein import from the cytosol, it is imperative that the cell eliminate any accumulated proteins in the event of mitochondrial protein import deficiency. Apparently, a significant portion of this activity involves ubiquitination in one way or another. In the present review article, following a brief introduction to mitochondrial protein quality control mechanisms, we discuss our recent understanding of intramitochondrial protein ubiquitination, its importance for basal function of mitochondria, metabolic implications, and possible therapeutic applications.
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Affiliation(s)
- Prasad Sulkshane
- Correspondence: (P.S.); (M.H.G.); Tel.: +972-58779-2319 (P.S.); +972-4-829-4552 (M.H.G.)
| | | | - Michael H Glickman
- Correspondence: (P.S.); (M.H.G.); Tel.: +972-58779-2319 (P.S.); +972-4-829-4552 (M.H.G.)
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264
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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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265
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Mitochondrial Carriers Regulating Insulin Secretion Profiled in Human Islets upon Metabolic Stress. Biomolecules 2020; 10:biom10111543. [PMID: 33198243 PMCID: PMC7697104 DOI: 10.3390/biom10111543] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 10/28/2020] [Accepted: 11/10/2020] [Indexed: 12/27/2022] Open
Abstract
Chronic exposure of β-cells to nutrient-rich metabolic stress impairs mitochondrial metabolism and its coupling to insulin secretion. We exposed isolated human islets to different metabolic stresses for 3 days: 0.4 mM oleate or 0.4 mM palmitate at physiological 5.5 mM glucose (lipotoxicity), high 25 mM glucose (glucotoxicity), and high 25 mM glucose combined with 0.4 mM oleate and/or palmitate (glucolipotoxicity). Then, we profiled the mitochondrial carriers and associated genes with RNA-Seq. Diabetogenic conditions, and in particular glucotoxicity, increased expression of several mitochondrial solute carriers in human islets, such as the malate carrier DIC, the α-ketoglutarate-malate exchanger OGC, and the glutamate carrier GC1. Glucotoxicity also induced a general upregulation of the electron transport chain machinery, while palmitate largely counteracted this effect. Expression of different components of the TOM/TIM mitochondrial protein import system was increased by glucotoxicity, whereas glucolipotoxicity strongly upregulated its receptor subunit TOM70. Expression of the mitochondrial calcium uniporter MCU was essentially preserved by metabolic stresses. However, glucotoxicity altered expression of regulatory elements of calcium influx as well as the Na+/Ca2+ exchanger NCLX, which mediates calcium efflux. Overall, the expression profile of mitochondrial carriers and associated genes was modified by the different metabolic stresses exhibiting nutrient-specific signatures.
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266
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The Origin of Mitochondria and their Role in the Evolution of Life and Human Health. ACTA BIOMEDICA SCIENTIFICA 2020. [DOI: 10.29413/abs.2020-5.5.2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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267
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Qin Q, Zhao T, Zou W, Shen K, Wang X. An Endoplasmic Reticulum ATPase Safeguards Endoplasmic Reticulum Identity by Removing Ectopically Localized Mitochondrial Proteins. Cell Rep 2020; 33:108363. [DOI: 10.1016/j.celrep.2020.108363] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 08/05/2020] [Accepted: 10/19/2020] [Indexed: 11/29/2022] Open
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268
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Kreimendahl S, Schwichtenberg J, Günnewig K, Brandherm L, Rassow J. The selectivity filter of the mitochondrial protein import machinery. BMC Biol 2020; 18:156. [PMID: 33121519 PMCID: PMC7596997 DOI: 10.1186/s12915-020-00888-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2020] [Accepted: 10/02/2020] [Indexed: 12/22/2022] Open
Abstract
Background The uptake of newly synthesized nuclear-encoded mitochondrial proteins from the cytosol is mediated by a complex of mitochondrial outer membrane proteins comprising a central pore-forming component and associated receptor proteins. Distinct fractions of proteins initially bind to the receptor proteins and are subsequently transferred to the pore-forming component for import. The aim of this study was the identification of the decisive elements of this machinery that determine the specific selection of the proteins that should be imported. Results We identified the essential internal targeting signal of the members of the mitochondrial metabolite carrier proteins, the largest protein family of the mitochondria, and we investigated the specific recognition of this signal by the protein import machinery at the mitochondrial outer surface. We found that the outer membrane import receptors facilitated the uptake of these proteins, and we identified the corresponding binding site, marked by cysteine C141 in the receptor protein Tom70. However, in tests both in vivo and in vitro, the import receptors were neither necessary nor sufficient for specific recognition of the targeting signals. Although these signals are unrelated to the amino-terminal presequences that mediate the targeting of other mitochondrial preproteins, they were found to resemble presequences in their strict dependence on a content of positively charged residues as a prerequisite of interactions with the import pore. Conclusions The general import pore of the mitochondrial outer membrane appears to represent not only the central channel of protein translocation but also to form the decisive general selectivity filter in the uptake of the newly synthesized mitochondrial proteins.
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Affiliation(s)
- Sebastian Kreimendahl
- Institute for Biochemistry and Pathobiochemistry, Ruhr-University Bochum, 44780, Bochum, Germany
| | - Jan Schwichtenberg
- Institute for Biochemistry and Pathobiochemistry, Ruhr-University Bochum, 44780, Bochum, Germany
| | - Kathrin Günnewig
- Institute for Biochemistry and Pathobiochemistry, Ruhr-University Bochum, 44780, Bochum, Germany
| | - Lukas Brandherm
- Institute for Biochemistry and Pathobiochemistry, Ruhr-University Bochum, 44780, Bochum, Germany
| | - Joachim Rassow
- Institute for Biochemistry and Pathobiochemistry, Ruhr-University Bochum, 44780, Bochum, Germany.
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269
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Dorji J, Vander Jagt CJ, Garner JB, Marett LC, Mason BA, Reich CM, Xiang R, Clark EL, Cocks BG, Chamberlain AJ, MacLeod IM, Daetwyler HD. Expression of mitochondrial protein genes encoded by nuclear and mitochondrial genomes correlate with energy metabolism in dairy cattle. BMC Genomics 2020; 21:720. [PMID: 33076826 PMCID: PMC7574280 DOI: 10.1186/s12864-020-07018-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 08/20/2020] [Indexed: 12/21/2022] Open
Abstract
Background Mutations in the mitochondrial genome have been implicated in mitochondrial disease, often characterized by impaired cellular energy metabolism. Cellular energy metabolism in mitochondria involves mitochondrial proteins (MP) from both the nuclear (NuMP) and mitochondrial (MtMP) genomes. The expression of MP genes in tissues may be tissue specific to meet varying specific energy demands across the tissues. Currently, the characteristics of MP gene expression in tissues of dairy cattle are not well understood. In this study, we profile the expression of MP genes in 29 adult and six foetal tissues in dairy cattle using RNA sequencing and gene expression analyses: particularly differential gene expression and co-expression network analyses. Results MP genes were differentially expressed (DE; over-expressed or under-expressed) across tissues in cattle. All 29 tissues showed DE NuMP genes in varying proportions of over-expression and under-expression. On the other hand, DE of MtMP genes was observed in < 50% of tissues and notably MtMP genes within a tissue was either all over-expressed or all under-expressed. A high proportion of NuMP (up to 60%) and MtMP (up to 100%) genes were over-expressed in tissues with expected high metabolic demand; heart, skeletal muscles and tongue, and under-expressed (up to 45% of NuMP, 77% of MtMP genes) in tissues with expected low metabolic rates; leukocytes, thymus, and lymph nodes. These tissues also invariably had the expression of all MtMP genes in the direction of dominant NuMP genes expression. The NuMP and MtMP genes were highly co-expressed across tissues and co-expression of genes in a cluster were non-random and functionally enriched for energy generation pathway. The differential gene expression and co-expression patterns were validated in independent cow and sheep datasets. Conclusions The results of this study support the concept that there are biological interaction of MP genes from the mitochondrial and nuclear genomes given their over-expression in tissues with high energy demand and co-expression in tissues. This highlights the importance of considering MP genes from both genomes in future studies related to mitochondrial functions and traits related to energy metabolism.
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Affiliation(s)
- Jigme Dorji
- School of Applied Systems Biology, La Trobe University, Bundoora, VIC, 3083, Australia. .,Agriculture Victoria, AgriBio, Centre for AgriBioscience, Bundoora, VIC, 3083, Australia.
| | - Christy J Vander Jagt
- Agriculture Victoria, AgriBio, Centre for AgriBioscience, Bundoora, VIC, 3083, Australia
| | - Josie B Garner
- Agriculture Victoria, Ellinbank Dairy Centre, Ellinbank, VIC, 3822, Australia
| | - Leah C Marett
- Agriculture Victoria, Ellinbank Dairy Centre, Ellinbank, VIC, 3822, Australia
| | - Brett A Mason
- Agriculture Victoria, AgriBio, Centre for AgriBioscience, Bundoora, VIC, 3083, Australia
| | - Coralie M Reich
- Agriculture Victoria, AgriBio, Centre for AgriBioscience, Bundoora, VIC, 3083, Australia
| | - Ruidong Xiang
- Agriculture Victoria, AgriBio, Centre for AgriBioscience, Bundoora, VIC, 3083, Australia.,Faculty of Veterinary & Agricultural Science, University of Melbourne, Parkville, VIC, 3052, Australia
| | - Emily L Clark
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, Scotland, UK
| | - Benjamin G Cocks
- School of Applied Systems Biology, La Trobe University, Bundoora, VIC, 3083, Australia.,Agriculture Victoria, AgriBio, Centre for AgriBioscience, Bundoora, VIC, 3083, Australia
| | - Amanda J Chamberlain
- Agriculture Victoria, AgriBio, Centre for AgriBioscience, Bundoora, VIC, 3083, Australia
| | - Iona M MacLeod
- Agriculture Victoria, AgriBio, Centre for AgriBioscience, Bundoora, VIC, 3083, Australia
| | - Hans D Daetwyler
- School of Applied Systems Biology, La Trobe University, Bundoora, VIC, 3083, Australia.,Agriculture Victoria, AgriBio, Centre for AgriBioscience, Bundoora, VIC, 3083, Australia
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270
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The ubiquitin-proteasome system and its crosstalk with mitochondria as therapeutic targets in medicine. Pharmacol Res 2020; 163:105248. [PMID: 33065283 DOI: 10.1016/j.phrs.2020.105248] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 10/06/2020] [Accepted: 10/07/2020] [Indexed: 12/12/2022]
Abstract
The ubiquitin-proteasome system constitutes a major pathway for protein degradation in the cell. Therefore the crosstalk of this pathway with mitochondria is a major topic with direct relevance to many mitochondrial diseases. Proteasome dysfunction triggers not only protein toxicity, but also mitochondrial dysfunction. The involvement of proteasomes in the regulation of protein transport into mitochondria contributes to an increase in mitochondrial function defects. On the other hand, mitochondrial impairment stimulates reactive oxygen species production, which increases protein damage, and protein misfolding and aggregation leading to proteasome overload. Concurrently, mitochondrial dysfunction compromises cellular ATP production leading to reduced protein ubiquitination and proteasome activity. In this review we discuss the complex relationship and interdependence of the ubiquitin-proteasome system and mitochondria. Furthermore, we describe pharmacological inhibition of proteasome activity as a novel strategy to treat a group of mitochondrial diseases.
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271
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Xia D. Structural snapshots of the cellular folded protein translocation machinery Bcs1. FEBS J 2020; 288:2870-2883. [PMID: 32979284 PMCID: PMC7994207 DOI: 10.1111/febs.15576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 09/05/2020] [Accepted: 09/22/2020] [Indexed: 11/29/2022]
Abstract
Proteins destined to various intra‐ and extra‐cellular locations must traverse membranes most frequently in an unfolded form. When the proteins being translocated need to remain in a folded state, specialized cellular transport machinery is used. One such machine is the membrane‐bound AAA protein Bcs1 (Bcs1), which assists the iron‐sulfur protein, an essential subunit of the respiratory Complex III, across the mitochondrial inner membrane. Recent structure determinations of mouse and yeast Bcs1 in three different nucleotide states reveal its homo‐heptameric association and at least two dramatically different conformations. The apo and ADP‐bound structures are similar, both containing a large substrate‐binding cavity accessible to the mitochondrial matrix space, which contracts by concerted motion of the ATPase domains upon ATP binding, suggesting that bound substrate could then be pushed across the membrane. ATP hydrolysis drives substrate release and resets Bcs1 conformation back to the apo/ADP form. These structures shed new light on the mechanism of folded protein translocation across a membrane, provide better understanding on the assembly process of the respiratory Complex III, and correlate clinical presentations of disease‐associated mutations with their locations in the 3D structure.
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Affiliation(s)
- Di Xia
- Laboratory of Cell Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
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272
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Mitochondrial biogenesis in organismal senescence and neurodegeneration. Mech Ageing Dev 2020; 191:111345. [DOI: 10.1016/j.mad.2020.111345] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 08/17/2020] [Accepted: 08/27/2020] [Indexed: 12/19/2022]
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273
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Wang W, Chen X, Zhang L, Yi J, Ma Q, Yin J, Zhuo W, Gu J, Yang M. Atomic structure of human TOM core complex. Cell Discov 2020; 6:67. [PMID: 33083003 PMCID: PMC7522991 DOI: 10.1038/s41421-020-00198-2] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Accepted: 07/20/2020] [Indexed: 12/22/2022] Open
Abstract
The translocase of the outer mitochondrial membrane (TOM) complex is the main entry gate for mitochondrial precursor proteins synthesized on cytosolic ribosomes. Here we report the single-particle cryo-electron microscopy (cryo-EM) structure of the dimeric human TOM core complex (TOM-CC). Two Tom40 β-barrel proteins, connected by two Tom22 receptor subunits and one phospholipid, form the protein-conducting channels. The small Tom proteins Tom5, Tom6, and Tom7 surround the channel and have notable configurations. The distinct electrostatic features of the complex, including the pronounced negative interior and the positive regions at the periphery and center of the dimer on the intermembrane space (IMS) side, provide insight into the preprotein translocation mechanism. Further, two dimeric TOM complexes may associate to form tetramer in the shape of a parallelogram, offering a potential explanation into the unusual structural features of Tom subunits and a new perspective of viewing the import of mitochondrial proteins.
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Affiliation(s)
- Wenhe Wang
- Ministry of Education Key Laboratory of Protein Science, Beijing Advanced Innovation Center for Structural Biology & Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, 100084 Beijing, China
| | - Xudong Chen
- Ministry of Education Key Laboratory of Protein Science, Beijing Advanced Innovation Center for Structural Biology & Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, 100084 Beijing, China
| | - Laixing Zhang
- Ministry of Education Key Laboratory of Protein Science, Beijing Advanced Innovation Center for Structural Biology & Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, 100084 Beijing, China
| | - Jingbo Yi
- Ministry of Education Key Laboratory of Protein Science, Beijing Advanced Innovation Center for Structural Biology & Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, 100084 Beijing, China
| | - Qingxi Ma
- Ministry of Education Key Laboratory of Protein Science, Beijing Advanced Innovation Center for Structural Biology & Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, 100084 Beijing, China
| | - Jian Yin
- Ministry of Education Key Laboratory of Protein Science, Beijing Advanced Innovation Center for Structural Biology & Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, 100084 Beijing, China
| | - Wei Zhuo
- Ministry of Education Key Laboratory of Protein Science, Beijing Advanced Innovation Center for Structural Biology & Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, 100084 Beijing, China
| | - Jinke Gu
- Ministry of Education Key Laboratory of Protein Science, Beijing Advanced Innovation Center for Structural Biology & Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, 100084 Beijing, China
| | - Maojun Yang
- Ministry of Education Key Laboratory of Protein Science, Beijing Advanced Innovation Center for Structural Biology & Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, 100084 Beijing, China
- School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030 Hubei China
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274
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Hara Y, Yanatori I, Tanaka A, Kishi F, Lemasters JJ, Nishina S, Sasaki K, Hino K. Iron loss triggers mitophagy through induction of mitochondrial ferritin. EMBO Rep 2020; 21:e50202. [PMID: 32975364 DOI: 10.15252/embr.202050202] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 07/30/2020] [Accepted: 08/12/2020] [Indexed: 12/19/2022] Open
Abstract
Mitochondrial quality is controlled by the selective removal of damaged mitochondria through mitophagy. Mitophagy impairment is associated with aging and many pathological conditions. An iron loss induced by iron chelator triggers mitophagy by a yet unknown mechanism. This type of mitophagy may have therapeutic potential, since iron chelators are clinically used. Here, we aimed to clarify the mechanisms by which iron loss induces mitophagy. Deferiprone, an iron chelator, treatment resulted in the increased expression of mitochondrial ferritin (FTMT) and the localization of FTMT precursor on the mitochondrial outer membrane. Specific protein 1 and its regulator hypoxia-inducible factor 1α were necessary for deferiprone-induced increase in FTMT. FTMT specifically interacted with nuclear receptor coactivator 4, an autophagic cargo receptor. Deferiprone-induced mitophagy occurred selectively for depolarized mitochondria. Additionally, deferiprone suppressed the development of hepatocellular carcinoma (HCC) in mice by inducing mitophagy. Silencing FTMT abrogated deferiprone-induced mitophagy and suppression of HCC. These results demonstrate the mechanisms by which iron loss induces mitophagy and provide a rationale for targeting mitophagic activation as a therapeutic strategy.
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Affiliation(s)
- Yuichi Hara
- Department of Hepatology and Pancreatology, Kawasaki Medical School, Kurashiki, Japan
| | - Izumi Yanatori
- Department of Molecular Genetics, Kawasaki Medical School, Kurashiki, Japan.,Department of Pathology and Biological Responses, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Atsushi Tanaka
- Research Institute of Medical Sciences, Yamagata University School of Medicine, Yamagata, Japan
| | - Fumio Kishi
- Department of Molecular Genetics, Kawasaki Medical School, Kurashiki, Japan
| | - John J Lemasters
- Department of Drug Discovery & Biomedical Sciences, Medical University of South Carolina, Charleston, SC, USA.,Department of Biochemistry & Molecular Biology, Medical University of South Carolina, Charleston, SC, USA
| | - Sohji Nishina
- Department of Hepatology and Pancreatology, Kawasaki Medical School, Kurashiki, Japan
| | - Kyo Sasaki
- Department of Hepatology and Pancreatology, Kawasaki Medical School, Kurashiki, Japan
| | - Keisuke Hino
- Department of Hepatology and Pancreatology, Kawasaki Medical School, Kurashiki, Japan
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275
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What Role Does COA6 Play in Cytochrome C Oxidase Biogenesis: A Metallochaperone or Thiol Oxidoreductase, or Both? Int J Mol Sci 2020; 21:ijms21196983. [PMID: 32977416 PMCID: PMC7582641 DOI: 10.3390/ijms21196983] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 09/21/2020] [Accepted: 09/21/2020] [Indexed: 12/27/2022] Open
Abstract
Complex IV (cytochrome c oxidase; COX) is the terminal complex of the mitochondrial electron transport chain. Copper is essential for COX assembly, activity, and stability, and is incorporated into the dinuclear CuA and mononuclear CuB sites. Multiple assembly factors play roles in the biogenesis of these sites within COX and the failure of this intricate process, such as through mutations to these factors, disrupts COX assembly and activity. Various studies over the last ten years have revealed that the assembly factor COA6, a small intermembrane space-located protein with a twin CX9C motif, plays a role in the biogenesis of the CuA site. However, how COA6 and its copper binding properties contribute to the assembly of this site has been a controversial area of research. In this review, we summarize our current understanding of the molecular mechanisms by which COA6 participates in COX biogenesis.
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276
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Hu Y, Zhao K, Qu Y, Song X, Zhao J, Qin Y. Penicillium oxalicum S-adenosylmethionine synthetase is essential for the viability of fungal cells and the expression of genes encoding cellulolytic enzymes. Fungal Biol 2020; 125:1-11. [PMID: 33317771 DOI: 10.1016/j.funbio.2020.09.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 09/03/2020] [Accepted: 09/15/2020] [Indexed: 01/20/2023]
Abstract
As the universal methyl donor for methylation reactions, S-adenosylmethionine (AdoMet) plays an indispensable role in most cellular metabolic processes. AdoMet is synthesized by AdoMet synthetase. We identified the only one AdoMet synthetase (PoSasA) in filamentous fungus Penicillium oxalicum. PoSasA was widely distributed in mycelium at different growth stages. The absence of PoSasA was lethal for P. oxalicum. The misregulation of the PoSasA encoding gene affected the synthesis of extracellular cellulolytic enzymes. The expression levels of cellobiohydrolase encoding gene cbh1/cel7A, β-1-4 endoglucanase eg1/cel7B, and xylanase encoding gene xyn10A were remarkably downregulated as a result of decreased PosasA gene expression. The production of extracellular cellulases and hemicellulases was also reduced. By contrast, the overexpression of PosasA improved the production of extracellular cellulases and hemicellulases. A total of 133 putative interacting proteins with PoSasA were identified using tandem affinity purification and mass spectrometry. The results of functional enrichment on these proteins showed that they were mainly related to ATP binding, magnesium ion binding, and ATP synthetase activity. Several methyltransferases were also observed among these proteins. These results were consistent with the intrinsic feature of AdoMet synthetase. This work reveals the indispensable role of PoSasA in various biological processes.
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Affiliation(s)
- Yueyan Hu
- National Glycoengineering Research Center, Shandong University, No. 72 Binhai Road, Qingdao, 266237, China; State Key Lab of Microbial Technology, Shandong University, No. 72 Binhai Road, Qingdao, 266237, China.
| | - Kaili Zhao
- National Glycoengineering Research Center, Shandong University, No. 72 Binhai Road, Qingdao, 266237, China; State Key Lab of Microbial Technology, Shandong University, No. 72 Binhai Road, Qingdao, 266237, China.
| | - Yinbo Qu
- National Glycoengineering Research Center, Shandong University, No. 72 Binhai Road, Qingdao, 266237, China; State Key Lab of Microbial Technology, Shandong University, No. 72 Binhai Road, Qingdao, 266237, China.
| | - Xin Song
- National Glycoengineering Research Center, Shandong University, No. 72 Binhai Road, Qingdao, 266237, China; State Key Lab of Microbial Technology, Shandong University, No. 72 Binhai Road, Qingdao, 266237, China.
| | - Jian Zhao
- National Glycoengineering Research Center, Shandong University, No. 72 Binhai Road, Qingdao, 266237, China.
| | - Yuqi Qin
- National Glycoengineering Research Center, Shandong University, No. 72 Binhai Road, Qingdao, 266237, China; State Key Lab of Microbial Technology, Shandong University, No. 72 Binhai Road, Qingdao, 266237, China.
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277
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Antón Z, Mullally G, Ford HC, van der Kamp MW, Szczelkun MD, Lane JD. Mitochondrial import, health and mtDNA copy number variability seen when using type II and type V CRISPR effectors. J Cell Sci 2020; 133:jcs.248468. [PMID: 32843580 DOI: 10.1242/jcs.248468] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 08/10/2020] [Indexed: 12/18/2022] Open
Abstract
Current methodologies for targeting the mitochondrial genome for research and/or therapy development in mitochondrial diseases are restricted by practical limitations and technical inflexibility. A molecular toolbox for CRISPR-mediated mitochondrial genome editing is desirable, as this could enable targeting of mtDNA haplotypes using the precision and tuneability of CRISPR enzymes. Such 'MitoCRISPR' systems described to date lack reproducibility and independent corroboration. We have explored the requirements for MitoCRISPR in human cells by CRISPR nuclease engineering, including the use of alternative mitochondrial protein targeting sequences and smaller paralogues, and the application of guide (g)RNA modifications for mitochondrial import. We demonstrate varied mitochondrial targeting efficiencies and effects on mitochondrial dynamics/function of different CRISPR nucleases, with Lachnospiraceae bacterium ND2006 (Lb) Cas12a being better targeted and tolerated than Cas9 variants. We also provide evidence of Cas9 gRNA association with mitochondria in HeLa cells and isolated yeast mitochondria, even in the absence of a targeting RNA aptamer. Our data link mitochondrial-targeted LbCas12a/crRNA with increased mtDNA copy number dependent upon DNA binding and cleavage activity. We discuss reproducibility issues and the future steps necessary for MitoCRISPR.
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Affiliation(s)
- Zuriñe Antón
- Cell Biology Laboratories, School of Biochemistry, Faculty of Life Sciences, University of Bristol, Bristol BS8 1TD, UK
| | - Grace Mullally
- DNA-Protein Interactions Unit, School of Biochemistry, Faculty of Life Sciences, University of Bristol, Bristol BS8 1TD, UK
| | - Holly C Ford
- DNA-Protein Interactions Unit, School of Biochemistry, Faculty of Life Sciences, University of Bristol, Bristol BS8 1TD, UK
| | - Marc W van der Kamp
- School of Biochemistry, Faculty of Life Sciences, University of Bristol, Bristol BS8 1TD, UK.,Centre for Computational Chemistry, School of Chemistry, Faculty of Science, University of Bristol, Bristol BS8 1TD, UK.,BrisSynBio, Life Sciences Building, Tyndall Avenue, University of Bristol, Bristol BS8 1TQ, UK
| | - Mark D Szczelkun
- DNA-Protein Interactions Unit, School of Biochemistry, Faculty of Life Sciences, University of Bristol, Bristol BS8 1TD, UK .,BrisSynBio, Life Sciences Building, Tyndall Avenue, University of Bristol, Bristol BS8 1TQ, UK
| | - Jon D Lane
- Cell Biology Laboratories, School of Biochemistry, Faculty of Life Sciences, University of Bristol, Bristol BS8 1TD, UK .,BrisSynBio, Life Sciences Building, Tyndall Avenue, University of Bristol, Bristol BS8 1TQ, UK
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278
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Thiriveedi VR, Mattam U, Pattabhi P, Bisoyi V, Talari NK, Krishnamoorthy T, Sepuri NBV. Glutathionylated and Fe-S cluster containing hMIA40 (CHCHD4) regulates ROS and mitochondrial complex III and IV activities of the electron transport chain. Redox Biol 2020; 37:101725. [PMID: 32971361 PMCID: PMC7511737 DOI: 10.1016/j.redox.2020.101725] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 09/02/2020] [Accepted: 09/11/2020] [Indexed: 12/14/2022] Open
Abstract
Human MIA40, an intermembrane space (IMS) import receptor of mitochondria harbors twin CX9C motifs for stability while its CPC motif is known to facilitate the import of IMS bound proteins. Site-directed mutagenesis complemented by MALDI on in vivo hMIA40 protein shows that a portion of MIA40 undergoes reversible S-glutathionylation at three cysteines in the twin CX9C motifs and the lone cysteine 4 residue. We find that HEK293T cells expressing hMIA40 mutant defective for glutathionylation are compromised in the activities of complexes III and IV of the Electron Transport Chain (ETC) and enhance Reactive Oxygen Species (ROS) levels. Immunocapture studies show MIA40 interacting with complex III. Interestingly, glutathionylated MIA40 can transfer electrons to cytochrome C directly. However, Fe–S clusters associated with the CPC motif are essential to facilitate the two-electron to one-electron transfer for reducing cytochrome C. These results suggest that hMIA40 undergoes glutathionylation to maintain ROS levels and for optimum function of complexes III and IV of ETC. Our studies shed light on a novel post-translational modification of hMIA40 and its ability to act as a redox switch to regulate the ETC and cellular redox homeostasis.
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Affiliation(s)
| | - Ushodaya Mattam
- Department of Biochemistry, University of Hyderabad, Gachibowli, Hyderabad, TS, 500046, India
| | - Prasad Pattabhi
- Department of Biochemistry, University of Hyderabad, Gachibowli, Hyderabad, TS, 500046, India
| | - Vandana Bisoyi
- Department of Biochemistry, University of Hyderabad, Gachibowli, Hyderabad, TS, 500046, India
| | - Noble Kumar Talari
- Department of Biochemistry, University of Hyderabad, Gachibowli, Hyderabad, TS, 500046, India
| | - Thanuja Krishnamoorthy
- Vectrogen Biologicals Pvt.Ltd., BioNEST, School of Life Sciences, University of Hyderabad, Gachibowli, Hyderabad, TS, 500046, India
| | - Naresh Babu V Sepuri
- Department of Biochemistry, University of Hyderabad, Gachibowli, Hyderabad, TS, 500046, India.
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279
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SAM50, a side door to the mitochondria: The case of cytotoxic proteases. Pharmacol Res 2020; 160:105196. [PMID: 32919042 DOI: 10.1016/j.phrs.2020.105196] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Revised: 08/26/2020] [Accepted: 09/03/2020] [Indexed: 12/21/2022]
Abstract
SAM50, a 7-8 nm diameter β-barrel channel of the mitochondrial outer membrane, is the central channel of the sorting and assembly machinery (SAM) complex involved in the biogenesis of β-barrel proteins. Interestingly, SAM50 is not known to have channel translocase activity; however, we have recently found that this channel is necessary and sufficient for mitochondrial entry of cytotoxic proteases. Cytotoxic lymphocytes eliminate cells that pose potential hazards, such as virus- and bacteria-infected cells as well as cancer cells. They induce cell death following the delivery of granzyme cytotoxic proteases into the cytosol of the target cell. Although granzyme A and granzyme B (GA and GB), the best characterized of the five human granzymes, trigger very distinct apoptotic cascades, they share the ability to directly target the mitochondria. GA and GB do not have a mitochondrial targeting signal, yet they enter the target cell mitochondria to disrupt respiratory chain complex I and induce mitochondrial reactive oxygen species (ROS)-dependent cell death. We found that granzyme mitochondrial entry requires SAM50 and the translocase of the inner membrane 22 (TIM22). Preventing granzymes' mitochondrial entry compromises their cytotoxicity, indicating that this event is unexpectedly an important step for cell death. Although mitochondria are best known for their roles in cell metabolism and energy conversion, these double-membrane organelles are also involved in Ca2+ homeostasis, metabolite transport, cell cycle regulation, cell signaling, differentiation, stress response, redox homeostasis, aging, and cell death. This multiplicity of functions is matched with the complexity and plasticity of the mitochondrial proteome as well as the organelle's morphological and structural versatility. Indeed, mitochondria are extremely dynamic and undergo fusion and fission events in response to diverse cellular cues. In humans, there are 1500 different mitochondrial proteins, the vast majority of which are encoded in the nuclear genome and translated by cytosolic ribosomes, after which they must be imported and properly addressed to the right mitochondrial compartment. To this end, mitochondria are equipped with a very sophisticated and highly specific protein import machinery. The latter is centered on translocase complexes embedded in the outer and inner mitochondrial membranes working along five different import pathways. We will briefly describe these import pathways to put into perspective our finding regarding the ability of granzymes to enter the mitochondria.
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280
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Gao F, Zhang Y, Hou X, Tao Z, Ren H, Wang G. Dependence of PINK1 accumulation on mitochondrial redox system. Aging Cell 2020; 19:e13211. [PMID: 32779864 PMCID: PMC7511888 DOI: 10.1111/acel.13211] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2020] [Revised: 07/10/2020] [Accepted: 07/13/2020] [Indexed: 11/28/2022] Open
Abstract
Accumulation of PINK1 on the outer mitochondrial membrane (OMM) is necessary for PINK-mediated mitophagy. The proton ionophores, like carbonyl cyanide m-chlorophenylhydrazone (CCCP) and carbonyl cyanide-4-(trifluoromethoxy)phenylhydrazone (FCCP), inhibit PINK1 import into mitochondrial matrix and induce PINK1 OMM accumulation. Here, we show that the CHCHD4/GFER disulfide relay system in the mitochondrial intermembrane space (IMS) is required for PINK1 stabilization when mitochondrial membrane potential is lost. Activation of CHCHD4/GFER system by mitochondrial oxidative stress or inhibition of CHCHD4/GFER system with antioxidants can promote or suppress PINK1 accumulation, respectively. Thus data suggest a pivotal role of CHCHD4/GFER system in PINK1 accumulation. The amyotrophic lateral sclerosis-related superoxide dismutase 1 mutants dysregulated redox state and CHCHD4/GFER system in the IMS, leading to inhibitions of PINK1 accumulation and mitophagy. Thus, the redox system in the IMS is involved in PINK1 accumulation and damaged mitochondrial clearance, which may play roles in mitochondrial dysfunction-related neurodegenerative diseases.
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Affiliation(s)
- Feng Gao
- Laboratory of Molecular Neuropathology Jiangsu Key laboratory of Neuropsychiatric Disorders & Department of Pharmacology College of Pharmaceutical Sciences Soochow University Suzhou Jiangsu China
- Neurodegenerative Disorder Research Center, Division of Life Sciences and Medicine University of Science and Technology of China Hefei Anhui China
| | - Yan Zhang
- Laboratory of Molecular Neuropathology Jiangsu Key laboratory of Neuropsychiatric Disorders & Department of Pharmacology College of Pharmaceutical Sciences Soochow University Suzhou Jiangsu China
| | - Xiaoou Hou
- Laboratory of Molecular Neuropathology Jiangsu Key laboratory of Neuropsychiatric Disorders & Department of Pharmacology College of Pharmaceutical Sciences Soochow University Suzhou Jiangsu China
| | - Zhouteng Tao
- Laboratory of Molecular Neuropathology Jiangsu Key laboratory of Neuropsychiatric Disorders & Department of Pharmacology College of Pharmaceutical Sciences Soochow University Suzhou Jiangsu China
- Center for Drug Safety Evaluation and Research State Key Laboratory of New Drug Research Shanghai Institute of Materia MedicaChinese Academy of Sciences Shanghai China
| | - Haigang Ren
- Laboratory of Molecular Neuropathology Jiangsu Key laboratory of Neuropsychiatric Disorders & Department of Pharmacology College of Pharmaceutical Sciences Soochow University Suzhou Jiangsu China
| | - Guanghui Wang
- Laboratory of Molecular Neuropathology Jiangsu Key laboratory of Neuropsychiatric Disorders & Department of Pharmacology College of Pharmaceutical Sciences Soochow University Suzhou Jiangsu China
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281
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Karakaidos P, Rampias T. Mitonuclear Interactions in the Maintenance of Mitochondrial Integrity. Life (Basel) 2020; 10:life10090173. [PMID: 32878185 PMCID: PMC7555762 DOI: 10.3390/life10090173] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 08/28/2020] [Indexed: 12/27/2022] Open
Abstract
In eukaryotic cells, mitochondria originated in an α-proteobacterial endosymbiont. Although these organelles harbor their own genome, the large majority of genes, originally encoded in the endosymbiont, were either lost or transferred to the nucleus. As a consequence, mitochondria have become semi-autonomous and most of their processes require the import of nuclear-encoded components to be functional. Therefore, the mitochondrial-specific translation has evolved to be coordinated by mitonuclear interactions to respond to the energetic demands of the cell, acquiring unique and mosaic features. However, mitochondrial-DNA-encoded genes are essential for the assembly of the respiratory chain complexes. Impaired mitochondrial function due to oxidative damage and mutations has been associated with numerous human pathologies, the aging process, and cancer. In this review, we highlight the unique features of mitochondrial protein synthesis and provide a comprehensive insight into the mitonuclear crosstalk and its co-evolution, as well as the vulnerabilities of the animal mitochondrial genome.
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282
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Skuratovskaia D, Komar A, Vulf M, Litvinova L. Mitochondrial destiny in type 2 diabetes: the effects of oxidative stress on the dynamics and biogenesis of mitochondria. PeerJ 2020; 8:e9741. [PMID: 32904391 PMCID: PMC7453922 DOI: 10.7717/peerj.9741] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Accepted: 07/26/2020] [Indexed: 12/28/2022] Open
Abstract
Background One reason for the development of insulin resistance is the chronic inflammation in obesity. Materials & Methods Scientific articles in the field of knowledge on the involvement of mitochondria and mitochondrial DNA (mtDNA) in obesity and type 2 diabetes were analyzed. Results Oxidative stress developed during obesity contributes to the formation of peroxynitrite, which causes cytochrome C-related damage in the mitochondrial electron transfer chain and increases the production of reactive oxygen species (ROS), which is associated with the development of type 2 diabetes. Oxidative stress contributes to the nuclease activity of the mitochondrial matrix, which leads to the accumulation of cleaved fragments and an increase in heteroplasmy. Mitochondrial dysfunction and mtDNA variations during insulin resistance may be connected with a change in ATP levels, generation of ROS, mitochondrial division/fusion and mitophagy. This review discusses the main role of mitochondria in the development of insulin resistance, which leads to pathological processes in insulin-dependent tissues, and considers potential therapeutic directions based on the modulation of mitochondrial biogenesis. In this regard, the development of drugs aimed at the regulation of these processes is gaining attention. Conclusion Changes in the mtDNA copy number can help to protect mitochondria from severe damage during conditions of increased oxidative stress. Mitochondrial proteome studies are conducted to search for potential therapeutic targets. The use of mitochondrial peptides encoded by mtDNA also represents a promising new approach to therapy.
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Affiliation(s)
| | - Alexandra Komar
- Immanuel Kant Baltic Federal University, Kaliningrad, Russian Federation
| | - Maria Vulf
- Immanuel Kant Baltic Federal University, Kaliningrad, Russian Federation
| | - Larisa Litvinova
- Immanuel Kant Baltic Federal University, Kaliningrad, Russian Federation
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283
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Sharanek A, Burban A, Laaper M, Heckel E, Joyal JS, Soleimani VD, Jahani-Asl A. OSMR controls glioma stem cell respiration and confers resistance of glioblastoma to ionizing radiation. Nat Commun 2020; 11:4116. [PMID: 32807793 PMCID: PMC7431428 DOI: 10.1038/s41467-020-17885-z] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Accepted: 07/22/2020] [Indexed: 12/13/2022] Open
Abstract
Glioblastoma contains a rare population of self-renewing brain tumor stem cells (BTSCs) which are endowed with properties to proliferate, spur the growth of new tumors, and at the same time, evade ionizing radiation (IR) and chemotherapy. However, the drivers of BTSC resistance to therapy remain unknown. The cytokine receptor for oncostatin M (OSMR) regulates BTSC proliferation and glioblastoma tumorigenesis. Here, we report our discovery of a mitochondrial OSMR that confers resistance to IR via regulation of oxidative phosphorylation, independent of its role in cell proliferation. Mechanistically, OSMR is targeted to the mitochondrial matrix via the presequence translocase-associated motor complex components, mtHSP70 and TIM44. OSMR interacts with NADH ubiquinone oxidoreductase 1/2 (NDUFS1/2) of complex I and promotes mitochondrial respiration. Deletion of OSMR impairs spare respiratory capacity, increases reactive oxygen species, and sensitizes BTSCs to IR-induced cell death. Importantly, suppression of OSMR improves glioblastoma response to IR and prolongs lifespan. The suppression of the receptor for oncostatin M (OSMR) can prevent glioblastoma cell growth. Here, the authors demonstrate a role for OSMR in modulating glioma stem cell respiration and its impact on resistance to ionizing radiation.
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Affiliation(s)
- Ahmad Sharanek
- Lady Davis Institute for Medical Research, Jewish General Hospital, 3755 Chemin de la Côte-Sainte-Catherine, Montréal, QC, H3T 1E2, Canada
| | - Audrey Burban
- Lady Davis Institute for Medical Research, Jewish General Hospital, 3755 Chemin de la Côte-Sainte-Catherine, Montréal, QC, H3T 1E2, Canada
| | - Matthew Laaper
- Lady Davis Institute for Medical Research, Jewish General Hospital, 3755 Chemin de la Côte-Sainte-Catherine, Montréal, QC, H3T 1E2, Canada.,Integrated program in Neuroscience, Montreal Neurological Institute, 3801 University Street, Montréal, QC, H3A 2B4, Canada
| | - Emilie Heckel
- Departments of Pediatrics, Pharmacology and Ophthalmology, Université de Montréal, CHU Sainte-Justine, Montréal, QC, H3T 1C5, Canada.,Department of Pharmacology and Therapeutics, McGill University, Montréal, QC, H3G 1Y6, Canada
| | - Jean-Sebastien Joyal
- Departments of Pediatrics, Pharmacology and Ophthalmology, Université de Montréal, CHU Sainte-Justine, Montréal, QC, H3T 1C5, Canada.,Department of Pharmacology and Therapeutics, McGill University, Montréal, QC, H3G 1Y6, Canada
| | - Vahab D Soleimani
- Lady Davis Institute for Medical Research, Jewish General Hospital, 3755 Chemin de la Côte-Sainte-Catherine, Montréal, QC, H3T 1E2, Canada.,Department of Human Genetics, McGill University, 3640 Rue University, Montréal, QC, H3A OC7, Canada
| | - Arezu Jahani-Asl
- Lady Davis Institute for Medical Research, Jewish General Hospital, 3755 Chemin de la Côte-Sainte-Catherine, Montréal, QC, H3T 1E2, Canada. .,Integrated program in Neuroscience, Montreal Neurological Institute, 3801 University Street, Montréal, QC, H3A 2B4, Canada. .,Gerald Bronfman Department of Oncology and Division of Experimental Medicine, McGill University, 5100 Maisonneuve Blvd West, Suite 720, H4A3T2, Montréal, QC, Canada.
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284
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Import of Entamoeba histolytica Mitosomal ATP Sulfurylase Relies on Internal Targeting Sequences. Microorganisms 2020; 8:microorganisms8081229. [PMID: 32806678 PMCID: PMC7465240 DOI: 10.3390/microorganisms8081229] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 08/11/2020] [Accepted: 08/11/2020] [Indexed: 11/17/2022] Open
Abstract
Mitochondrial matrix proteins synthesized in the cytosol often contain amino (N)-terminal targeting sequences (NTSs), or alternately internal targeting sequences (ITSs), which enable them to be properly translocated to the organelle. Such sequences are also required for proteins targeted to mitochondrion-related organelles (MROs) that are present in a few species of anaerobic eukaryotes. Similar to other MROs, the mitosomes of the human intestinal parasite Entamoeba histolytica are highly degenerate, because a majority of the components involved in various processes occurring in the canonical mitochondria are either missing or modified. As of yet, sulfate activation continues to be the only identified role of the relic mitochondria of Entamoeba. Mitosomes influence the parasitic nature of E. histolytica, as the downstream cytosolic products of sulfate activation have been reported to be essential in proliferation and encystation. Here, we investigated the position of the targeting sequence of one of the mitosomal matrix enzymes involved in the sulfate activation pathway, ATP sulfurylase (AS). We confirmed by immunofluorescence assay and subcellular fractionation that hemagluttinin (HA)-tagged EhAS was targeted to mitosomes. However, its ortholog in the δ-proteobacterium Desulfovibrio vulgaris, expressed as DvAS-HA in amoebic trophozoites, indicated cytosolic localization, suggesting a lack of recognizable mitosome targeting sequence in this protein. By expressing chimeric proteins containing swapped sequences between EhAS and DvAS in amoebic cells, we identified the ITSs responsible for mitosome targeting of EhAS. This observation is similar to other parasitic protozoans that harbor MROs, suggesting a convergent feature among various MROs in favoring ITS for the recognition and translocation of targeted proteins.
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285
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Cytosolic Events in the Biogenesis of Mitochondrial Proteins. Trends Biochem Sci 2020; 45:650-667. [DOI: 10.1016/j.tibs.2020.04.001] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2020] [Revised: 03/18/2020] [Accepted: 04/02/2020] [Indexed: 01/08/2023]
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286
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Bader G, Enkler L, Araiso Y, Hemmerle M, Binko K, Baranowska E, De Craene JO, Ruer-Laventie J, Pieters J, Tribouillard-Tanvier D, Senger B, di Rago JP, Friant S, Kucharczyk R, Becker HD. Assigning mitochondrial localization of dual localized proteins using a yeast Bi-Genomic Mitochondrial-Split-GFP. eLife 2020; 9:56649. [PMID: 32657755 PMCID: PMC7358010 DOI: 10.7554/elife.56649] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Accepted: 06/11/2020] [Indexed: 12/31/2022] Open
Abstract
A single nuclear gene can be translated into a dual localized protein that distributes between the cytosol and mitochondria. Accumulating evidences show that mitoproteomes contain lots of these dual localized proteins termed echoforms. Unraveling the existence of mitochondrial echoforms using current GFP (Green Fluorescent Protein) fusion microscopy approaches is extremely difficult because the GFP signal of the cytosolic echoform will almost inevitably mask that of the mitochondrial echoform. We therefore engineered a yeast strain expressing a new type of Split-GFP that we termed Bi-Genomic Mitochondrial-Split-GFP (BiG Mito-Split-GFP). Because one moiety of the GFP is translated from the mitochondrial machinery while the other is fused to the nuclear-encoded protein of interest translated in the cytosol, the self-reassembly of this Bi-Genomic-encoded Split-GFP is confined to mitochondria. We could authenticate the mitochondrial importability of any protein or echoform from yeast, but also from other organisms such as the human Argonaute 2 mitochondrial echoform.
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Affiliation(s)
- Gaétan Bader
- Université de Strasbourg, CNRS UMR7156, Génétique Moléculaire, Génomique, Microbiologie, Strasbourg, France
| | - Ludovic Enkler
- Université de Strasbourg, CNRS UMR7156, Génétique Moléculaire, Génomique, Microbiologie, Strasbourg, France
| | - Yuhei Araiso
- Université de Strasbourg, CNRS UMR7156, Génétique Moléculaire, Génomique, Microbiologie, Strasbourg, France
| | - Marine Hemmerle
- Université de Strasbourg, CNRS UMR7156, Génétique Moléculaire, Génomique, Microbiologie, Strasbourg, France
| | - Krystyna Binko
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Emilia Baranowska
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Johan-Owen De Craene
- Université de Strasbourg, CNRS UMR7156, Génétique Moléculaire, Génomique, Microbiologie, Strasbourg, France
| | | | - Jean Pieters
- Biozentrum, University of Basel, Basel, Switzerland
| | | | - Bruno Senger
- Université de Strasbourg, CNRS UMR7156, Génétique Moléculaire, Génomique, Microbiologie, Strasbourg, France
| | - Jean-Paul di Rago
- Institut de Biochimie et Génétique Cellulaires, CNRS UMR5095, Université de Bordeaux, Bordeaux, France
| | - Sylvie Friant
- Université de Strasbourg, CNRS UMR7156, Génétique Moléculaire, Génomique, Microbiologie, Strasbourg, France
| | - Roza Kucharczyk
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Hubert Dominique Becker
- Université de Strasbourg, CNRS UMR7156, Génétique Moléculaire, Génomique, Microbiologie, Strasbourg, France
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287
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Dutta D, Briere LC, Kanca O, Marcogliese PC, Walker MA, High FA, Vanderver A, Krier J, Carmichael N, Callahan C, Taft RJ, Simons C, Helman G, Network UD, Wangler MF, Yamamoto S, Sweetser DA, Bellen HJ. De novo mutations in TOMM70, a receptor of the mitochondrial import translocase, cause neurological impairment. Hum Mol Genet 2020; 29:1568-1579. [PMID: 32356556 PMCID: PMC7268787 DOI: 10.1093/hmg/ddaa081] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 04/02/2020] [Accepted: 04/24/2020] [Indexed: 12/20/2022] Open
Abstract
The translocase of outer mitochondrial membrane (TOMM) complex is the entry gate for virtually all mitochondrial proteins and is essential to build the mitochondrial proteome. TOMM70 is a receptor that assists mainly in mitochondrial protein import. Here, we report two individuals with de novo variants in the C-terminal region of TOMM70. While both individuals exhibited shared symptoms including hypotonia, hyper-reflexia, ataxia, dystonia and significant white matter abnormalities, there were differences between the two individuals, most prominently the age of symptom onset. Both individuals were undiagnosed despite extensive genetics workups. Individual 1 was found to have a p.Thr607Ile variant while Individual 2 was found to have a p.Ile554Phe variant in TOMM70. To functionally assess both TOMM70 variants, we replaced the Drosophila Tom70 coding region with a Kozak-mini-GAL4 transgene using CRISPR-Cas9. Homozygous mutant animals die as pupae, but lethality is rescued by the mini-GAL4-driven expression of human UAS-TOMM70 cDNA. Both modeled variants lead to significantly less rescue indicating that they are loss-of-function alleles. Similarly, RNAi-mediated knockdown of Tom70 in the developing eye causes roughening and synaptic transmission defect, common findings in neurodegenerative and mitochondrial disorders. These phenotypes were rescued by the reference, but not the variants, of TOMM70. Altogether, our data indicate that de novo loss-of-function variants in TOMM70 result in variable white matter disease and neurological phenotypes in affected individuals.
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Affiliation(s)
- Debdeep Dutta
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, TX 77030, USA
| | - Lauren C Briere
- Division of Medical Genetics and Metabolism, Department of Pediatrics, Massachusetts General Hospital for Children, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Oguz Kanca
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, TX 77030, USA
| | - Paul C Marcogliese
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, TX 77030, USA
| | - Melissa A Walker
- Department of Neurology, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Frances A High
- Division of Medical Genetics and Metabolism, Department of Pediatrics, Massachusetts General Hospital for Children, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Adeline Vanderver
- Division of Neurology, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Joel Krier
- Brigham Genomic Medicine, Brigham and Women’s Hospital, Boston, MA 02115, USA
| | - Nikkola Carmichael
- Brigham Genomic Medicine, Brigham and Women’s Hospital, Boston, MA 02115, USA
| | - Christine Callahan
- Department of Medicine, Brigham and Women’s Hospital, Boston, MA 02115, USA
| | | | - Cas Simons
- Murdoch Children's Research Institute, The Royal Children’s Hospital, Parkville, Victoria 3052, Australia
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Guy Helman
- Murdoch Children's Research Institute, The Royal Children’s Hospital, Parkville, Victoria 3052, Australia
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia
| | | | - Michael F Wangler
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, TX 77030, USA
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Shinya Yamamoto
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, TX 77030, USA
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
| | - David A Sweetser
- Division of Medical Genetics and Metabolism, Department of Pediatrics, Massachusetts General Hospital for Children, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Hugo J Bellen
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, TX 77030, USA
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
- Howard Hughes Medical Institute, Baylor College of Medicine, Houston, TX 77030, USA
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288
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Sultana S, Stewart J, van der Spoel AC. Truncated mutants of beta-glucosidase 2 (GBA2) are localized in the mitochondrial matrix and cause mitochondrial fragmentation. PLoS One 2020; 15:e0233856. [PMID: 32492073 PMCID: PMC7269613 DOI: 10.1371/journal.pone.0233856] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Accepted: 05/13/2020] [Indexed: 12/22/2022] Open
Abstract
The enzyme β-glucosidase 2 (GBA2) is clinically relevant because it is targeted by the drug miglustat (Zavesca®) and because it is involved in inherited diseases. Mutations in the GBA2 gene are associated with two neurological diseases on the ataxia-spasticity spectrum, hereditary spastic paraplegia 46 (SPG46) and Marinesco-Sjögren-like syndrome (MSS). To establish how GBA2 mutations give rise to neurological pathology, we have begun to investigate mutant forms of GBA2 encoded by disease-associated GBA2 alleles. Previously, we found that five GBA2 missense mutants and five C-terminally truncated mutants lacked enzyme activity. Here we have examined the cellular locations of wild-type (WT) and mutant forms of GBA2 by confocal and electron microscopy, using transfected cells. Similar to GBA2-WT, the D594H and M510Vfs*17 GBA2 mutants were located at the plasma membrane, whereas the C-terminally truncated mutants terminating after amino acids 233 and 339 (GBA2-233 and -339) were present in the mitochondrial matrix, induced mitochondrial fragmentation and loss of mitochondrial transmembrane potential. Deletional mutagenesis indicated that residues 161–200 are critical for the mitochondrial fragmentation of GBA2-233 and -339. Considering that the mitochondrial fragmentation induced by GBA2-233 and -339 is consistently accompanied by their localization to the mitochondrial matrix, our deletional analysis raises the possibility that that GBA2 residues 161–200 harbor an internal targeting sequence for transport to the mitochondrial matrix. Altogether, our work provides new insights into the behaviour of GBA2-WT and disease-associated forms of GBA2.
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Affiliation(s)
- Saki Sultana
- The Atlantic Research Centre, Department of Biochemistry & Molecular Biology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Jacklyn Stewart
- Biomedical Sciences Program, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Aarnoud C. van der Spoel
- The Atlantic Research Centre, Department of Biochemistry & Molecular Biology, Dalhousie University, Halifax, Nova Scotia, Canada
- The Atlantic Research Centre, Department of Pediatrics, Dalhousie University, Halifax, Nova Scotia, Canada
- * E-mail:
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289
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Tran HC, Van Aken O. Mitochondrial unfolded protein-related responses across kingdoms: similar problems, different regulators. Mitochondrion 2020; 53:166-177. [PMID: 32502630 DOI: 10.1016/j.mito.2020.05.009] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 05/19/2020] [Accepted: 05/22/2020] [Indexed: 02/06/2023]
Abstract
Mitochondria are key components of eukaryotic cells, so their proper functioning is monitored via different mitochondrial signalling responses. One of these mitochondria-to-nuclear 'retrograde' responses to maintain mitochondrial homeostasis is the mitochondrial unfolded protein response (UPRmt), which can be activated by a variety of defects including blocking mitochondrial translation, respiration, protein import or transmembrane potential. Although UPRmt was first reported in cultured mammalian cells, this signalling pathway has also been extensively studied in the nematode Caenorhabditis elegans. In yeast, there are no published studies focusing on UPRmt in a strict sense, but other unfolded protein responses (UPR) that appear related to UPRmt have been described, such as the UPR activated by protein mistargeting (UPRam) and mitochondrial compromised protein import response (mitoCPR). In plants, very little is known about UPRmt and only recently some of the regulators have been identified. In this paper, we summarise and compare the current knowledge of the UPRmt and related responses across eukaryotic kingdoms: animals, fungi and plants. Our comparison suggests that each kingdom has evolved its own specific set of regulators, however, the functional categories represented among UPRmt-related target genes appear to be largely overlapping. This indicates that the strategies for preserving proper mitochondrial functions are partially conserved, targeting mitochondrial chaperones, proteases, import components, dynamics and stress response, but likely also non-mitochondrial functions including growth regulators/hormone balance and amino acid metabolism. We also identify homologs of known UPRmt regulators and responsive genes across kingdoms, which may be interesting targets for future research.
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290
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Stephan K, Ott M. Timing of dimerization of the bc complex during mitochondrial respiratory chain assembly. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2020; 1861:148177. [DOI: 10.1016/j.bbabio.2020.148177] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 02/21/2020] [Accepted: 02/27/2020] [Indexed: 11/28/2022]
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291
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Avendaño-Monsalve MC, Ponce-Rojas JC, Funes S. From cytosol to mitochondria: the beginning of a protein journey. Biol Chem 2020; 401:645-661. [DOI: 10.1515/hsz-2020-0110] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Accepted: 02/24/2020] [Indexed: 01/18/2023]
Abstract
AbstractMitochondrial protein import is one of the key processes during mitochondrial biogenesis that involves a series of events necessary for recognition and delivery of nucleus-encoded/cytosol-synthesized mitochondrial proteins into the organelle. The past research efforts have mainly unraveled how membrane translocases ensure the correct protein sorting within the different mitochondrial subcompartments. However, early steps of recognition and delivery remain relatively uncharacterized. In this review, we discuss our current understanding about the signals on mitochondrial proteins, as well as in the mRNAs encoding them, which with the help of cytosolic chaperones and membrane receptors support protein targeting to the organelle in order to avoid improper localization. In addition, we discuss recent findings that illustrate how mistargeting of mitochondrial proteins triggers stress responses, aiming to restore cellular homeostasis.
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Affiliation(s)
- Maria Clara Avendaño-Monsalve
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Circuito Exterior s/n Ciudad Universitaria Coyoacán, México, Cd.Mx. 04510, Mexico
| | - José Carlos Ponce-Rojas
- Department of Molecular, Cellular, and Developmental Biology, University of California at Santa Barbara, Santa Barbara, CA 93106-9625, USA
| | - Soledad Funes
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Circuito Exterior s/n Ciudad Universitaria Coyoacán, México, Cd.Mx. 04510, Mexico
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292
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Yang W, Shin HY, Cho H, Chung JY, Lee EJ, Kim JH, Kang ES. TOM40 Inhibits Ovarian Cancer Cell Growth by Modulating Mitochondrial Function Including Intracellular ATP and ROS Levels. Cancers (Basel) 2020; 12:cancers12051329. [PMID: 32456076 PMCID: PMC7281007 DOI: 10.3390/cancers12051329] [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] [Received: 04/09/2020] [Revised: 05/12/2020] [Accepted: 05/19/2020] [Indexed: 12/17/2022] Open
Abstract
TOM40 is a channel-forming subunit of translocase, which is essential for the movement of proteins into the mitochondria. We found that TOM40 was highly expressed in epithelial ovarian cancer (EOC) cells at both the transcriptional and translational levels; its expression increased significantly during the transformation from normal ovarian epithelial cells to EOC (p < 0.001), and TOM40 expression negatively correlated with disease-free survival (Hazard ratio = 1.79, 95% Confidence inerval 1.16–2.78, p = 0.009). TOM40 knockdown decreased proliferation in several EOC cell lines and reduced tumor burden in an in vivo xenograft mouse model. TOM40 expression positively correlated with intracellular adenosine triphosphate (ATP) levels. The low ATP and high reactive oxygen species (ROS) levels increased the activity of AMP-activated protein kinase (AMPK) in TOM40 knockdown EOC cells. However, AMPK activity did not correlate with declined cell growth in TOM40 knockdown EOC cells. We found that metformin, first-line therapy for type 2 diabetes, effectively inhibited the growth of EOC cell lines in an AMPK-independent manner by inhibiting mitochondria complex I. In conclusion, TOM40 positively correlated with mitochondrial activities, and its association enhances the proliferation of ovarian cancer. Also, metformin is an effective therapeutic option in TOM40 overexpressed ovarian cancer than normal ovarian epithelium.
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Affiliation(s)
- Wookyeom Yang
- Department of Obstetrics and Gynecology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul 06273, Korea; (W.Y.); (H.-Y.S.); (H.C.); (E.-j.L.)
| | - Ha-Yeon Shin
- Department of Obstetrics and Gynecology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul 06273, Korea; (W.Y.); (H.-Y.S.); (H.C.); (E.-j.L.)
| | - Hanbyoul Cho
- Department of Obstetrics and Gynecology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul 06273, Korea; (W.Y.); (H.-Y.S.); (H.C.); (E.-j.L.)
| | - Joon-Yong Chung
- Laboratory of Pathology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA;
| | - Eun-ju Lee
- Department of Obstetrics and Gynecology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul 06273, Korea; (W.Y.); (H.-Y.S.); (H.C.); (E.-j.L.)
| | - Jae-Hoon Kim
- Department of Obstetrics and Gynecology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul 06273, Korea; (W.Y.); (H.-Y.S.); (H.C.); (E.-j.L.)
- Correspondence: (J.-H.K.); (E.-S.K.); Tel.:+82-2-2019-3430 (J.-H.K.); +82-2-3410-2703 (E.-S.K.); Fax: +82-2-3462-8209 (J.-H.K.); +82-2-3410-2719 (E.-S.K.)
| | - Eun-Suk Kang
- Department of Laboratory Medicine and Genetics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 06351, Korea
- Correspondence: (J.-H.K.); (E.-S.K.); Tel.:+82-2-2019-3430 (J.-H.K.); +82-2-3410-2703 (E.-S.K.); Fax: +82-2-3462-8209 (J.-H.K.); +82-2-3410-2719 (E.-S.K.)
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293
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O'Malley J, Kumar R, Inigo J, Yadava N, Chandra D. Mitochondrial Stress Response and Cancer. Trends Cancer 2020; 6:688-701. [PMID: 32451306 DOI: 10.1016/j.trecan.2020.04.009] [Citation(s) in RCA: 75] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 04/16/2020] [Accepted: 04/22/2020] [Indexed: 12/20/2022]
Abstract
Cancer cells survive and adapt to many types of stress including hypoxia, nutrient deprivation, metabolic, and oxidative stress. These stresses are sensed by diverse cellular signaling processes, leading to either degradation of mitochondria or alleviation of mitochondrial stress. This review discusses signaling during sensing and mitigation of stress involving mitochondrial communication with the endoplasmic reticulum, and how retrograde signaling upregulates the mitochondrial stress response to maintain mitochondrial integrity. The importance of the mitochondrial unfolded protein response, an emerging pathway that alleviates cellular stress, will be elaborated with respect to cancer. Detailed understanding of cellular pathways will establish mitochondrial stress response as a key mechanism for cancer cell survival leading to cancer progression and resistance, and provide a potential therapeutic target in cancer.
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Affiliation(s)
- Jordan O'Malley
- Department of Pharmacology and Therapeutics, Roswell Park Comprehensive Cancer Center, Buffalo, NY, USA
| | - Rahul Kumar
- Department of Pharmacology and Therapeutics, Roswell Park Comprehensive Cancer Center, Buffalo, NY, USA
| | - Joseph Inigo
- Department of Pharmacology and Therapeutics, Roswell Park Comprehensive Cancer Center, Buffalo, NY, USA
| | - Nagendra Yadava
- Department of Anesthesiology and Center for Shock, Trauma, and Anesthesiology Research, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Dhyan Chandra
- Department of Pharmacology and Therapeutics, Roswell Park Comprehensive Cancer Center, Buffalo, NY, USA.
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294
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Piantadosi CA. Mitochondrial DNA, oxidants, and innate immunity. Free Radic Biol Med 2020; 152:455-461. [PMID: 31958498 DOI: 10.1016/j.freeradbiomed.2020.01.013] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Revised: 01/09/2020] [Accepted: 01/13/2020] [Indexed: 12/14/2022]
Abstract
Mitochondrial oxidant damage, including damage to mitochondrial DNA (mtDNA) is a feature of both severe microbial infections and inflammation arising from sterile (non-infectious) sources such as tissue trauma. Damaged mitochondria release intact or oxidized fragments of mtDNA into the cytoplasm, which represent oxidant injury, and the fragments promote a spontaneous innate immune response, exemplifying a modern frontier of immunological research. MtDNA and mitochondrial-derived oxidants are central factors in activating at least three innate immune pathways involving the TLR9 (Toll-like receptor 9), the NLRP3 (NACHT, LRR and PYD domains-containing protein-3) inflammasome, and the cGAS (cyclic AMP-GMP synthase) pathway. The events that allow mtDNA to escape from damaged mitochondria and from damaged cells are incompletely known, but the presence of cytoplasmic mtDNA and cell-free mtDNA as immune regulators are important for understanding the cell's capacity for protecting mitochondrial quality control (MQC) and cell viability during inflammatory states.
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295
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Jadiya P, Tomar D. Mitochondrial Protein Quality Control Mechanisms. Genes (Basel) 2020; 11:genes11050563. [PMID: 32443488 PMCID: PMC7290828 DOI: 10.3390/genes11050563] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 05/14/2020] [Accepted: 05/15/2020] [Indexed: 02/08/2023] Open
Abstract
Mitochondria serve as a hub for many cellular processes, including bioenergetics, metabolism, cellular signaling, redox balance, calcium homeostasis, and cell death. The mitochondrial proteome includes over a thousand proteins, encoded by both the mitochondrial and nuclear genomes. The majority (~99%) of proteins are nuclear encoded that are synthesized in the cytosol and subsequently imported into the mitochondria. Within the mitochondria, polypeptides fold and assemble into their native functional form. Mitochondria health and integrity depend on correct protein import, folding, and regulated turnover termed as mitochondrial protein quality control (MPQC). Failure to maintain these processes can cause mitochondrial dysfunction that leads to various pathophysiological outcomes and the commencement of diseases. Here, we summarize the current knowledge about the role of different MPQC regulatory systems such as mitochondrial chaperones, proteases, the ubiquitin-proteasome system, mitochondrial unfolded protein response, mitophagy, and mitochondria-derived vesicles in the maintenance of mitochondrial proteome and health. The proper understanding of mitochondrial protein quality control mechanisms will provide relevant insights to treat multiple human diseases.
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Affiliation(s)
- Pooja Jadiya
- Correspondence: (P.J.); (D.T.); Tel.: +1-215-707-9144 (D.T.)
| | - Dhanendra Tomar
- Correspondence: (P.J.); (D.T.); Tel.: +1-215-707-9144 (D.T.)
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296
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Molenaars M, Daniels EG, Meurs A, Janssens GE, Houtkooper RH. Mitochondrial cross-compartmental signalling to maintain proteostasis and longevity. Philos Trans R Soc Lond B Biol Sci 2020; 375:20190414. [PMID: 32362258 DOI: 10.1098/rstb.2019.0414] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Lifespan in eukaryotic species can be prolonged by shifting from cellular states favouring growth to those favouring maintenance and stress resistance. For instance, perturbations in mitochondrial oxidative phosphorylation (OXPHOS) can shift cells into this latter state and extend lifespan. Because mitochondria rely on proteins synthesized from nuclear as well as mitochondrial DNA, they need to constantly send and receive messages from other compartments of the cell in order to function properly and maintain homeostasis, and lifespan extension is often dependent on this cross-compartmental signalling. Here, we describe the mechanisms of bi-directional mitochondrial cross-compartmental signalling resulting in proteostasis and longevity. These proteostasis mechanisms are highly context-dependent, governed by the origin and extent of stress. Furthermore, we discuss the translatability of these mechanisms and explore therapeutic developments, such as the antibiotic studies targeting mitochondria or mitochondria-derived peptides as therapies for age-related diseases such as neurodegeneration and cancer. This article is part of the theme issue 'Retrograde signalling from endosymbiotic organelles'.
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Affiliation(s)
- Marte Molenaars
- Laboratory Genetic Metabolic Diseases, Amsterdam UMC, University of Amsterdam, Amsterdam Gastroenterology and Metabolism, Amsterdam Cardiovascular Sciences, Amsterdam, The Netherlands
| | - Eileen G Daniels
- Laboratory Genetic Metabolic Diseases, Amsterdam UMC, University of Amsterdam, Amsterdam Gastroenterology and Metabolism, Amsterdam Cardiovascular Sciences, Amsterdam, The Netherlands
| | - Amber Meurs
- Laboratory Genetic Metabolic Diseases, Amsterdam UMC, University of Amsterdam, Amsterdam Gastroenterology and Metabolism, Amsterdam Cardiovascular Sciences, Amsterdam, The Netherlands
| | - Georges E Janssens
- Laboratory Genetic Metabolic Diseases, Amsterdam UMC, University of Amsterdam, Amsterdam Gastroenterology and Metabolism, Amsterdam Cardiovascular Sciences, Amsterdam, The Netherlands
| | - Riekelt H Houtkooper
- Laboratory Genetic Metabolic Diseases, Amsterdam UMC, University of Amsterdam, Amsterdam Gastroenterology and Metabolism, Amsterdam Cardiovascular Sciences, Amsterdam, The Netherlands
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297
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Pfannschmidt T, Terry MJ, Van Aken O, Quiros PM. Retrograde signals from endosymbiotic organelles: a common control principle in eukaryotic cells. Philos Trans R Soc Lond B Biol Sci 2020; 375:20190396. [PMID: 32362267 DOI: 10.1098/rstb.2019.0396] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Endosymbiotic organelles of eukaryotic cells, the plastids, including chloroplasts and mitochondria, are highly integrated into cellular signalling networks. In both heterotrophic and autotrophic organisms, plastids and/or mitochondria require extensive organelle-to-nucleus communication in order to establish a coordinated expression of their own genomes with the nuclear genome, which encodes the majority of the components of these organelles. This goal is achieved by the use of a variety of signals that inform the cell nucleus about the number and developmental status of the organelles and their reaction to changing external environments. Such signals have been identified in both photosynthetic and non-photosynthetic eukaryotes (known as retrograde signalling and retrograde response, respectively) and, therefore, appear to be universal mechanisms acting in eukaryotes of all kingdoms. In particular, chloroplasts and mitochondria both harbour crucial redox reactions that are the basis of eukaryotic life and are, therefore, especially susceptible to stress from the environment, which they signal to the rest of the cell. These signals are crucial for cell survival, lifespan and environmental adjustment, and regulate quality control and targeted degradation of dysfunctional organelles, metabolic adjustments, and developmental signalling, as well as induction of apoptosis. The functional similarities between retrograde signalling pathways in autotrophic and non-autotrophic organisms are striking, suggesting the existence of common principles in signalling mechanisms or similarities in their evolution. Here, we provide a survey for the newcomers to this field of research and discuss the importance of retrograde signalling in the context of eukaryotic evolution. Furthermore, we discuss commonalities and differences in retrograde signalling mechanisms and propose retrograde signalling as a general signalling mechanism in eukaryotic cells that will be also of interest for the specialist. This article is part of the theme issue 'Retrograde signalling from endosymbiotic organelles'.
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Affiliation(s)
- Thomas Pfannschmidt
- Institute of Botany, Plant Physiology, Leibniz University Hannover, Herrenhäuser Straße 2, 30419 Hannover, Germany
| | - Matthew J Terry
- School of Biological Sciences, University of Southampton, Southampton SO17 1BJ, UK
| | - Olivier Van Aken
- Department of Biology, Lund University, Sölvegatan 35, 223 62 Lund, Sweden
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298
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Causes and consequences of mitochondrial proteome size variation in animals. Mitochondrion 2020; 52:100-107. [DOI: 10.1016/j.mito.2020.02.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 12/23/2019] [Accepted: 02/13/2020] [Indexed: 12/25/2022]
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299
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Bertero E, Kutschka I, Maack C, Dudek J. Cardiolipin remodeling in Barth syndrome and other hereditary cardiomyopathies. Biochim Biophys Acta Mol Basis Dis 2020; 1866:165803. [PMID: 32348916 DOI: 10.1016/j.bbadis.2020.165803] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 12/19/2019] [Accepted: 04/13/2020] [Indexed: 12/18/2022]
Abstract
Mitochondria play a prominent role in cardiac energy metabolism, and their function is critically dependent on the integrity of mitochondrial membranes. Disorders characterized by mitochondrial dysfunction are commonly associated with cardiac disease. The mitochondrial phospholipid cardiolipin directly interacts with a number of essential protein complexes in the mitochondrial membranes including the respiratory chain, mitochondrial metabolite carriers, and proteins critical for mitochondrial morphology. Barth syndrome is an X-linked disorder caused by an inherited defect in the biogenesis of the mitochondrial phospholipid cardiolipin. How cardiolipin deficiency impacts on mitochondrial function and how mitochondrial dysfunction causes cardiomyopathy has been intensively studied in cellular and animal models of Barth syndrome. These findings may also have implications for the molecular mechanisms underlying other inherited disorders associated with defects in cardiolipin, such as Sengers syndrome and dilated cardiomyopathy with ataxia (DCMA).
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Affiliation(s)
- Edoardo Bertero
- Comprehensive Heart Failure Center (CHFC), University Clinic Würzburg, 97078 Würzburg, Germany
| | - Ilona Kutschka
- Comprehensive Heart Failure Center (CHFC), University Clinic Würzburg, 97078 Würzburg, Germany
| | - Christoph Maack
- Comprehensive Heart Failure Center (CHFC), University Clinic Würzburg, 97078 Würzburg, Germany
| | - Jan Dudek
- Comprehensive Heart Failure Center (CHFC), University Clinic Würzburg, 97078 Würzburg, Germany.
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300
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Ravanelli S, den Brave F, Hoppe T. Mitochondrial Quality Control Governed by Ubiquitin. Front Cell Dev Biol 2020; 8:270. [PMID: 32391359 PMCID: PMC7193050 DOI: 10.3389/fcell.2020.00270] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Accepted: 03/30/2020] [Indexed: 12/15/2022] Open
Abstract
Mitochondria are essential organelles important for energy production, proliferation, and cell death. Biogenesis, homeostasis, and degradation of this organelle are tightly controlled to match cellular needs and counteract chronic stress conditions. Despite providing their own DNA, the vast majority of mitochondrial proteins are encoded in the nucleus, synthesized by cytosolic ribosomes, and subsequently imported into different mitochondrial compartments. The integrity of the mitochondrial proteome is permanently challenged by defects in folding, transport, and turnover of mitochondrial proteins. Therefore, damaged proteins are constantly sequestered from the outer mitochondrial membrane and targeted for proteasomal degradation in the cytosol via mitochondrial-associated degradation (MAD). Recent studies identified specialized quality control mechanisms important to decrease mislocalized proteins, which affect the mitochondrial import machinery. Interestingly, central factors of these ubiquitin-dependent pathways are shared with the ER-associated degradation (ERAD) machinery, indicating close collaboration between both tubular organelles. Here, we summarize recently described cellular stress response mechanisms, which are triggered by defects in mitochondrial protein import and quality control. Moreover, we discuss how ubiquitin-dependent degradation is integrated with cytosolic stress responses, particularly focused on the crosstalk between MAD and ERAD.
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Affiliation(s)
- Sonia Ravanelli
- Institute for Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, University of Cologne, Cologne, Germany
| | - Fabian den Brave
- Department of Molecular Cell Biology, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Thorsten Hoppe
- Institute for Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, University of Cologne, Cologne, Germany.,Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
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