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Makki A, Kereïche S, Le T, Kučerová J, Rada P, Žárský V, Hrdý I, Tachezy J. A hybrid TIM complex mediates protein import into hydrogenosomes of Trichomonas vaginalis. BMC Biol 2024; 22:130. [PMID: 38825681 PMCID: PMC11145794 DOI: 10.1186/s12915-024-01928-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Accepted: 05/22/2024] [Indexed: 06/04/2024] Open
Abstract
BACKGROUND Hydrogenosomes are a specific type of mitochondria that have adapted for life under anaerobiosis. Limited availability of oxygen has resulted in the loss of the membrane-associated respiratory chain, and consequently in the generation of minimal inner membrane potential (Δψ), and inefficient ATP synthesis via substrate-level phosphorylation. The changes in energy metabolism are directly linked with the organelle biogenesis. In mitochondria, proteins are imported across the outer membrane via the Translocase of the Outer Membrane (TOM complex), while two Translocases of the Inner Membrane, TIM22, and TIM23, facilitate import to the inner membrane and matrix. TIM23-mediated steps are entirely dependent on Δψ and ATP hydrolysis, while TIM22 requires only Δψ. The character of the hydrogenosomal inner membrane translocase and the mechanism of translocation is currently unknown. RESULTS We report unprecedented modification of TIM in hydrogenosomes of the human parasite Trichomonas vaginalis (TvTIM). We show that the import of the presequence-containing protein into the hydrogenosomal matrix is mediated by the hybrid TIM22-TIM23 complex that includes three highly divergent core components, TvTim22, TvTim23, and TvTim17-like proteins. The hybrid character of the TvTIM is underlined by the presence of both TvTim22 and TvTim17/23, association with small Tim chaperones (Tim9-10), which in mitochondria are known to facilitate the transfer of substrates to the TIM22 complex, and the coupling with TIM23-specific ATP-dependent presequence translocase-associated motor (PAM). Interactome reconstruction based on co-immunoprecipitation (coIP) and mass spectrometry revealed that hybrid TvTIM is formed with the compositional variations of paralogs. Single-particle electron microscopy for the 132-kDa purified TvTIM revealed the presence of a single ring of small Tims complex, while mitochondrial TIM22 complex bears twin small Tims hexamer. TvTIM is currently the only TIM visualized outside of Opisthokonta, which raised the question of which form is prevailing across eukaryotes. The tight association of the hybrid TvTIM with ADP/ATP carriers (AAC) suggests that AAC may directly supply ATP for the protein import since ATP synthesis is limited in hydrogenosomes. CONCLUSIONS The hybrid TvTIM in hydrogenosomes represents an original structural solution that evolved for protein import when Δψ is negligible and remarkable example of evolutionary adaptation to an anaerobic lifestyle.
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Affiliation(s)
- Abhijith Makki
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Průmyslová 595, 25250, Vestec, Czech Republic
- Present address: Department of Cellular Biochemistry, University Medical Center Göttingen, D-37073, Göttingen, Germany
| | - Sami Kereïche
- Institute of Biology and Medical Genetics, First Faculty of Medicine, Charles University, Albertov 4, 12800, Prague 2, Czech Republic
| | - Tien Le
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Průmyslová 595, 25250, Vestec, Czech Republic
| | - Jitka Kučerová
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Průmyslová 595, 25250, Vestec, Czech Republic
| | - Petr Rada
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Průmyslová 595, 25250, Vestec, Czech Republic
| | - Vojtěch Žárský
- Department of Biology and Ecology, Faculty of Science, University of Ostrava, Ostrava, Czech Republic
| | - Ivan Hrdý
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Průmyslová 595, 25250, Vestec, Czech Republic
| | - Jan Tachezy
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Průmyslová 595, 25250, Vestec, Czech Republic.
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Ayadi I, Nebli S, Ben Marzoug R, Rebai A. Charge cluster occurrence in land plants' mitochondrial proteomes with functional and structural insights. J Biomol Struct Dyn 2024:1-11. [PMID: 38345014 DOI: 10.1080/07391102.2024.2313154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2023] [Accepted: 01/25/2024] [Indexed: 03/22/2024]
Abstract
The Charge Clusters (CCs) are involved in key functions and are distributed according to the organism, the protein's type, and the charge of amino acids. In the present study, we have explored the occurrence, position, and annotation as a first large-scale study of the CCs in land plants mitochondrial proteomes. A new python script was used for data curation. The Finding Clusters Charge in Protein Sequences Program was performed after adjusting the reading window size. A 44316 protein sequences belonging to 52 species of land plants were analysed. The occurrence of Negative Charge Clusters (NCCs) (1.2%) is two times more frequent than the Positive Charge Clusters (PCCs) (0.64%). Moreover, 39 and 30 NCCs were conserved in 88 and 41 proteins in intra and in inter proteomes respectively, while 14 and 21 PCCs were conserved in 53 and 85 protein sequences in intra and inter proteomes consecutively. Sequences carrying mixed CCs are rare (0.12%). Despite this low abundance, CCs play a crucial role in protein function. The CCs tend to be located mainly in the terminal regions of proteins which guarantees specific protein targeting and import into the mitochondria. In addition, the functional annotation of CCs according to Gene Ontology shows that CCs are involved in binding functions of either proteins or macromolecules which are deployed in different metabolic and cellular processes such as RNA editing and transcription. This study may provide valuable information while considering the CCs in understanding the environmental adaptation of plants.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Imen Ayadi
- Laboratory of Molecular and Cellular Screening Processes, Centre of Biotechnology of Sfax, University of Sfax, Sfax, Tunisia
| | - Syrine Nebli
- Laboratory of Molecular and Cellular Screening Processes, Centre of Biotechnology of Sfax, University of Sfax, Sfax, Tunisia
| | - Riadh Ben Marzoug
- Laboratory of Molecular and Cellular Screening Processes, Centre of Biotechnology of Sfax, University of Sfax, Sfax, Tunisia
| | - Ahmed Rebai
- Laboratory of Molecular and Cellular Screening Processes, Centre of Biotechnology of Sfax, University of Sfax, Sfax, Tunisia
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3
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Sim SI, Chen Y, Lynch DL, Gumbart JC, Park E. Structural basis of mitochondrial protein import by the TIM23 complex. Nature 2023; 621:620-626. [PMID: 37344598 DOI: 10.1038/s41586-023-06239-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2021] [Accepted: 05/19/2023] [Indexed: 06/23/2023]
Abstract
Mitochondria import nearly all of their approximately 1,000-2,000 constituent proteins from the cytosol across their double-membrane envelope1-5. Genetic and biochemical studies have shown that the conserved protein translocase, termed the TIM23 complex, mediates import of presequence-containing proteins (preproteins) into the mitochondrial matrix and inner membrane. Among about ten different subunits of the TIM23 complex, the essential multipass membrane protein Tim23, together with the evolutionarily related protein Tim17, has long been postulated to form a protein-conducting channel6-11. However, the mechanism by which these subunits form a translocation path in the membrane and enable the import process remains unclear due to a lack of structural information. Here we determined the cryo-electron microscopy structure of the core TIM23 complex (heterotrimeric Tim17-Tim23-Tim44) from Saccharomyces cerevisiae. Contrary to the prevailing model, Tim23 and Tim17 themselves do not form a water-filled channel, but instead have separate, lipid-exposed concave cavities that face in opposite directions. Our structural and biochemical analyses show that the cavity of Tim17, but not Tim23, forms the protein translocation path, whereas Tim23 probably has a structural role. The results further suggest that, during translocation of substrate polypeptides, the nonessential subunit Mgr2 seals the lateral opening of the Tim17 cavity to facilitate the translocation process. We propose a new model for the TIM23-mediated protein import and sorting mechanism, a central pathway in mitochondrial biogenesis.
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Affiliation(s)
- Sue Im Sim
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
| | - Yuanyuan Chen
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
- California Institute for Quantitative Biosciences, University of California, Berkeley, CA, USA
| | - Diane L Lynch
- School of Physics, Georgia Institute of Technology, Atlanta, GA, USA
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA, USA
| | - James C Gumbart
- School of Physics, Georgia Institute of Technology, Atlanta, GA, USA
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA, USA
| | - Eunyong Park
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA.
- California Institute for Quantitative Biosciences, University of California, Berkeley, CA, USA.
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4
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Napolitano G, Fasciolo G, Muscari Tomajoli MT, Venditti P. Changes in the Mitochondria in the Aging Process-Can α-Tocopherol Affect Them? Int J Mol Sci 2023; 24:12453. [PMID: 37569829 PMCID: PMC10419829 DOI: 10.3390/ijms241512453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 07/28/2023] [Accepted: 08/03/2023] [Indexed: 08/13/2023] Open
Abstract
Aerobic organisms use molecular oxygen in several reactions, including those in which the oxidation of substrate molecules is coupled to oxygen reduction to produce large amounts of metabolic energy. The utilization of oxygen is associated with the production of ROS, which can damage biological macromolecules but also act as signaling molecules, regulating numerous cellular processes. Mitochondria are the cellular sites where most of the metabolic energy is produced and perform numerous physiological functions by acting as regulatory hubs of cellular metabolism. They retain the remnants of their bacterial ancestors, including an independent genome that encodes part of their protein equipment; they have an accurate quality control system; and control of cellular functions also depends on communication with the nucleus. During aging, mitochondria can undergo dysfunctions, some of which are mediated by ROS. In this review, after a description of how aging affects the mitochondrial quality and quality control system and the involvement of mitochondria in inflammation, we report information on how vitamin E, the main fat-soluble antioxidant, can protect mitochondria from age-related changes. The information in this regard is scarce and limited to some tissues and some aspects of mitochondrial alterations in aging. Improving knowledge of the effects of vitamin E on aging is essential to defining an optimal strategy for healthy aging.
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Affiliation(s)
- Gaetana Napolitano
- Department of Science and Technology, University of Naples Parthenope, Via Acton n. 38, I-80133 Naples, Italy; (G.N.); (M.T.M.T.)
| | - Gianluca Fasciolo
- Department of Biology, University of Naples ‘Napoli Federico II’, Complesso Universitario di Monte Sant’Angelo, Via Cinthia, I-80126 Naples, Italy;
| | - Maria Teresa Muscari Tomajoli
- Department of Science and Technology, University of Naples Parthenope, Via Acton n. 38, I-80133 Naples, Italy; (G.N.); (M.T.M.T.)
| | - Paola Venditti
- Department of Biology, University of Naples ‘Napoli Federico II’, Complesso Universitario di Monte Sant’Angelo, Via Cinthia, I-80126 Naples, Italy;
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5
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Chojnacka KJ, Elancheliyan P, Mussulini BHM, Mohanraj K, Callegari S, Gosk A, Banach T, Góral T, Szczepanowska K, Rehling P, Serwa RA, Chacińska A. Ovarian carcinoma immunoreactive antigen-like protein 2 (OCIAD2) is a novel complex III specific assembly factor in mitochondria. Mol Biol Cell 2022; 33:ar29. [PMID: 35080992 PMCID: PMC9250361 DOI: 10.1091/mbc.e21-03-0143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Assembly of the dimeric complex III (CIII2) in the mitochondrial inner membrane is an intricate process in which several accessory proteins are involved as assembly factors. Despite numerous studies, this process has yet to be fully understood. Here we report the identification of human OCIAD2 (ovarian carcinoma immunoreactive antigen–like protein 2) as an assembly factor for CIII2. OCIAD2 was found to be deregulated in several carcinomas and also in some neurogenerative disorders; however, its nonpathological role had not been elucidated. We have shown that OCIAD2 localizes to mitochondria and interacts with electron transport chain (ETC) proteins. Complete loss of OCIAD2 using gene editing in HEK293 cells resulted in abnormal mitochondrial morphology, a substantial decrease of both CIII2 and supercomplex III2+IV, and a reduction in CIII enzymatic activity. Identification of OCIAD2 as a protein required for assembly of functional CIII2 provides a new insight into the biogenesis and architecture of the ETC. Elucidating the mechanism of OCIAD2 action is important both for the understanding of cellular metabolism and for an understanding of its role in malignant transformation.
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Affiliation(s)
| | | | | | - Karthik Mohanraj
- ReMedy International Research Agenda Unit, IMol Polish Academy of Sciences, Warsaw, Poland
| | - Sylvie Callegari
- Ubiquitin Signalling Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia.,Department of Cellular Biochemistry, University Medical Center Göttingen, 37073, Göttingen, Germany
| | - Aleksandra Gosk
- Centre of New Technologies, University of Warsaw, 02-097 Warsaw, Poland
| | - Tomasz Banach
- ReMedy International Research Agenda Unit, IMol Polish Academy of Sciences, Warsaw, Poland
| | - Tomasz Góral
- Centre of New Technologies, University of Warsaw, 02-097 Warsaw, Poland
| | - Karolina Szczepanowska
- ReMedy International Research Agenda Unit, IMol Polish Academy of Sciences, Warsaw, Poland
| | - Peter Rehling
- Department of Cellular Biochemistry, University Medical Center Göttingen, 37073, Göttingen, Germany.,Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Goettingen, Germany.,Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Remigiusz Adam Serwa
- ReMedy International Research Agenda Unit, IMol Polish Academy of Sciences, Warsaw, Poland
| | - Agnieszka Chacińska
- ReMedy International Research Agenda Unit, IMol Polish Academy of Sciences, Warsaw, Poland
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6
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Zhao F, Zou MH. Role of the Mitochondrial Protein Import Machinery and Protein Processing in Heart Disease. Front Cardiovasc Med 2021; 8:749756. [PMID: 34651031 PMCID: PMC8505727 DOI: 10.3389/fcvm.2021.749756] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 08/26/2021] [Indexed: 12/12/2022] Open
Abstract
Mitochondria are essential organelles for cellular energy production, metabolic homeostasis, calcium homeostasis, cell proliferation, and apoptosis. About 99% of mammalian mitochondrial proteins are encoded by the nuclear genome, synthesized as precursors in the cytosol, and imported into mitochondria by mitochondrial protein import machinery. Mitochondrial protein import systems function not only as independent units for protein translocation, but also are deeply integrated into a functional network of mitochondrial bioenergetics, protein quality control, mitochondrial dynamics and morphology, and interaction with other organelles. Mitochondrial protein import deficiency is linked to various diseases, including cardiovascular disease. In this review, we describe an emerging class of protein or genetic variations of components of the mitochondrial import machinery involved in heart disease. The major protein import pathways, including the presequence pathway (TIM23 pathway), the carrier pathway (TIM22 pathway), and the mitochondrial intermembrane space import and assembly machinery, related translocases, proteinases, and chaperones, are discussed here. This review highlights the importance of mitochondrial import machinery in heart disease, which deserves considerable attention, and further studies are urgently needed. Ultimately, this knowledge may be critical for the development of therapeutic strategies in heart disease.
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Affiliation(s)
- Fujie Zhao
- Center for Molecular and Translational Medicine, Georgia State University, Atlanta, GA, United States
| | - Ming-Hui Zou
- Center for Molecular and Translational Medicine, Georgia State University, Atlanta, GA, United States
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7
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Singh T, Jiao Y, Ferrando LM, Yablonska S, Li F, Horoszko EC, Lacomis D, Friedlander RM, Carlisle DL. Neuronal mitochondrial dysfunction in sporadic amyotrophic lateral sclerosis is developmentally regulated. Sci Rep 2021; 11:18916. [PMID: 34556702 PMCID: PMC8460779 DOI: 10.1038/s41598-021-97928-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Accepted: 09/01/2021] [Indexed: 02/08/2023] Open
Abstract
Amyotrophic lateral sclerosis is an adult-onset neurodegenerative disorder characterized by loss of motor neurons. Mitochondria are essential for neuronal survival but the developmental timing and mechanistic importance of mitochondrial dysfunction in sporadic ALS (sALS) neurons is not fully understood. We used human induced pluripotent stem cells and generated a developmental timeline by differentiating sALS iPSCs to neural progenitors and to motor neurons and comparing mitochondrial parameters with familial ALS (fALS) and control cells at each developmental stage. We report that sALS and fALS motor neurons have elevated reactive oxygen species levels, depolarized mitochondria, impaired oxidative phosphorylation, ATP loss and defective mitochondrial protein import compared with control motor neurons. This phenotype develops with differentiation into motor neurons, the affected cell type in ALS, and does not occur in the parental undifferentiated sALS cells or sALS neural progenitors. Our work demonstrates a developmentally regulated unifying mitochondrial phenotype between patient derived sALS and fALS motor neurons. The occurrence of a unifying mitochondrial phenotype suggests that mitochondrial etiology known to SOD1-fALS may applicable to sALS. Furthermore, our findings suggest that disease-modifying treatments focused on rescue of mitochondrial function may benefit both sALS and fALS patients.
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Affiliation(s)
- Tanisha Singh
- grid.21925.3d0000 0004 1936 9000Neuroapoptosis Laboratory, Department of Neurological Surgery, University of Pittsburgh, B400 Presbyterian Hospital, 200 Lothrop Street, Pittsburgh, PA 15213 USA
| | - Yuanyuan Jiao
- grid.21925.3d0000 0004 1936 9000Neuroapoptosis Laboratory, Department of Neurological Surgery, University of Pittsburgh, B400 Presbyterian Hospital, 200 Lothrop Street, Pittsburgh, PA 15213 USA
| | - Lisa M. Ferrando
- grid.21925.3d0000 0004 1936 9000Neuroapoptosis Laboratory, Department of Neurological Surgery, University of Pittsburgh, B400 Presbyterian Hospital, 200 Lothrop Street, Pittsburgh, PA 15213 USA
| | - Svitlana Yablonska
- grid.21925.3d0000 0004 1936 9000Neuroapoptosis Laboratory, Department of Neurological Surgery, University of Pittsburgh, B400 Presbyterian Hospital, 200 Lothrop Street, Pittsburgh, PA 15213 USA
| | - Fang Li
- grid.21925.3d0000 0004 1936 9000Neuroapoptosis Laboratory, Department of Neurological Surgery, University of Pittsburgh, B400 Presbyterian Hospital, 200 Lothrop Street, Pittsburgh, PA 15213 USA
| | - Emily C. Horoszko
- grid.21925.3d0000 0004 1936 9000Neuroapoptosis Laboratory, Department of Neurological Surgery, University of Pittsburgh, B400 Presbyterian Hospital, 200 Lothrop Street, Pittsburgh, PA 15213 USA
| | - David Lacomis
- grid.21925.3d0000 0004 1936 9000Departments of Neurology and Pathology, University of Pittsburgh, Pittsburgh, PA 15213 USA
| | - Robert M. Friedlander
- grid.21925.3d0000 0004 1936 9000Neuroapoptosis Laboratory, Department of Neurological Surgery, University of Pittsburgh, B400 Presbyterian Hospital, 200 Lothrop Street, Pittsburgh, PA 15213 USA
| | - Diane L. Carlisle
- grid.21925.3d0000 0004 1936 9000Neuroapoptosis Laboratory, Department of Neurological Surgery, University of Pittsburgh, B400 Presbyterian Hospital, 200 Lothrop Street, Pittsburgh, PA 15213 USA
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8
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TAT-Conjugated NDUFS8 Can Be Transduced into Mitochondria in a Membrane-Potential-Independent Manner and Rescue Complex I Deficiency. Int J Mol Sci 2021; 22:ijms22126524. [PMID: 34204592 PMCID: PMC8234171 DOI: 10.3390/ijms22126524] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 06/12/2021] [Accepted: 06/15/2021] [Indexed: 12/21/2022] Open
Abstract
NADH dehydrogenase (ubiquinone) Fe-S protein 8 (NDUFS8) is a nuclear-encoded core subunit of human mitochondrial complex I. Defects in NDUFS8 are associated with Leigh syndrome and encephalomyopathy. Cell-penetrating peptide derived from the HIV-1 transactivator of transcription protein (TAT) has been successfully applied as a carrier to bring fusion proteins into cells without compromising the biological function of the cargoes. In this study, we developed a TAT-mediated protein transduction system to rescue complex I deficiency caused by NDUFS8 defects. Two fusion proteins (TAT-NDUFS8 and NDUFS8-TAT) were exogenously expressed and purified from Escherichia coli for transduction of human cells. In addition, similar constructs were generated and used in transfection studies for comparison. The results showed that both exogenous TAT-NDUFS8 and NDUFS8-TAT were delivered into mitochondria and correctly processed. Interestingly, the mitochondrial import of TAT-containing NDUFS8 was independent of mitochondrial membrane potential. Treatment with TAT-NDUFS8 not only significantly improved the assembly of complex I in an NDUFS8-deficient cell line, but also partially rescued complex I functions both in the in-gel activity assay and the oxygen consumption assay. Our current findings suggest the considerable potential of applying the TAT-mediated protein transduction system for treatment of complex I deficiency.
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Transmembrane Coordination of Preprotein Recognition and Motor Coupling by the Mitochondrial Presequence Receptor Tim50. Cell Rep 2021; 30:3092-3104.e4. [PMID: 32130909 DOI: 10.1016/j.celrep.2020.02.031] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2019] [Revised: 12/13/2019] [Accepted: 02/07/2020] [Indexed: 01/05/2023] Open
Abstract
Mitochondrial preproteins contain amino-terminal presequences directing them to the presequence translocase of the mitochondrial inner membrane (TIM23 complex). Depending on additional downstream import signals, TIM23 either inserts preproteins into the inner membrane or translocates them into the matrix. Matrix import requires the coupling of the presequence translocase-associated motor (PAM) to TIM23. The molecular mechanisms coordinating preprotein recognition by TIM23 in the intermembrane space (IMS) with PAM activation in the matrix are unknown. Here we show that subsequent to presequence recognition in the IMS, the Tim50 matrix domain facilitates the recruitment of the coupling factor Pam17. Next, the IMS domain of Tim50 promotes PAM recruitment to TIM23. Finally, the Tim50 transmembrane segment stimulates the matrix-directed import-driving force exerted by PAM. We propose that recognition of preprotein segments in the IMS and transfer of signal information across the inner membrane by Tim50 determine import motor activation.
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10
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Abstract
Significance: In addition to their classical role in cellular ATP production, mitochondria are of key relevance in various (patho)physiological mechanisms including second messenger signaling, neuro-transduction, immune responses and death induction. Recent Advances: Within cells, mitochondria are motile and display temporal changes in internal and external structure ("mitochondrial dynamics"). During the last decade, substantial empirical and in silico evidence was presented demonstrating that mitochondrial dynamics impacts on mitochondrial function and vice versa. Critical Issues: However, a comprehensive and quantitative understanding of the bidirectional links between mitochondrial external shape, internal structure and function ("morphofunction") is still lacking. The latter particularly hampers our understanding of the functional properties and behavior of individual mitochondrial within single living cells. Future Directions: In this review we discuss the concept of mitochondrial morphofunction in mammalian cells, primarily using experimental evidence obtained within the last decade. The topic is introduced by briefly presenting the central role of mitochondria in cell physiology and the importance of the mitochondrial electron transport chain (ETC) therein. Next, we summarize in detail how mitochondrial (ultra)structure is controlled and discuss empirical evidence regarding the equivalence of mitochondrial (ultra)structure and function. Finally, we provide a brief summary of how mitochondrial morphofunction can be quantified at the level of single cells and mitochondria, how mitochondrial ultrastructure/volume impacts on mitochondrial bioreactions and intramitochondrial protein diffusion, and how mitochondrial morphofunction can be targeted by small molecules.
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Affiliation(s)
- Elianne P. Bulthuis
- Department of Biochemistry (286), Radboud Institute for Molecular Life Sciences, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Merel J.W. Adjobo-Hermans
- Department of Biochemistry (286), Radboud Institute for Molecular Life Sciences, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Peter H.G.M. Willems
- Department of Biochemistry (286), Radboud Institute for Molecular Life Sciences, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Werner J.H. Koopman
- Department of Biochemistry (286), Radboud Institute for Molecular Life Sciences, Radboud University Medical Centre, Nijmegen, The Netherlands
- Address correspondence to: Dr. Werner J.H. Koopman, Department of Biochemistry (286), Radboud Institute for Molecular Life Sciences, Radboud University Medical Centre, P.O. Box 9101, Nijmegen NL-6500 HB, The Netherlands
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11
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Mitochondrial presequence import: Multiple regulatory knobs fine-tune mitochondrial biogenesis and homeostasis. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2019; 1866:930-944. [PMID: 30802482 DOI: 10.1016/j.bbamcr.2019.02.012] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2019] [Revised: 02/14/2019] [Accepted: 02/19/2019] [Indexed: 12/22/2022]
Abstract
Mitochondria are pivotal organelles for cellular signaling and metabolism, and their dysfunction leads to severe cellular stress. About 60-70% of the mitochondrial proteome consists of preproteins synthesized in the cytosol with an amino-terminal cleavable presequence targeting signal. The TIM23 complex transports presequence signals towards the mitochondrial matrix. Ultimately, the mature protein segments are either transported into the matrix or sorted to the inner membrane. To ensure accurate preprotein import into distinct mitochondrial sub-compartments, the TIM23 machinery adopts specific functional conformations and interacts with different partner complexes. Regulatory subunits modulate the translocase dynamics, tailoring the import reaction to the incoming preprotein. The mitochondrial membrane potential and the ATP generated via oxidative phosphorylation are key energy sources in driving the presequence import pathway. Thus, mitochondrial dysfunctions have rapid repercussions on biogenesis. Cellular mechanisms exploit the presequence import pathway to monitor mitochondrial dysfunctions and mount transcriptional and proteostatic responses to restore functionality.
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12
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Myristoyl group-aided protein import into the mitochondrial intermembrane space. Sci Rep 2019; 9:1185. [PMID: 30718713 PMCID: PMC6362269 DOI: 10.1038/s41598-018-38016-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Accepted: 12/12/2018] [Indexed: 12/20/2022] Open
Abstract
The MICOS complex mediates formation of the crista junctions in mitochondria. Here we analyzed the mitochondrial import pathways for the six yeast MICOS subunits as a step toward understanding of the assembly mechanisms of the MICOS complex. Mic10, Mic12, Mic26, Mic27, and Mic60 used the presequence pathway to reach the intermembrane space (IMS). In contrast, Mic19 took the TIM40/MIA pathway, through its CHCH domain, to reach the IMS. Unlike canonical TIM40/MIA substrates, presence of the N-terminal unfolded DUF domain impaired the import efficiency of Mic19, yet N-terminal myristoylation of Mic19 circumvented this effect. The myristoyl group of Mic19 binds to Tom20 of the TOM complex as well as the outer membrane, which may lead to “entropy pushing” of the DUF domain followed by the CHCH domain of Mic19 into the import channel, thereby achieving efficient import.
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Reyes A, Melchionda L, Burlina A, Robinson AJ, Ghezzi D, Zeviani M. Mutations in TIMM50 compromise cell survival in OxPhos-dependent metabolic conditions. EMBO Mol Med 2018; 10:emmm.201708698. [PMID: 30190335 PMCID: PMC6180300 DOI: 10.15252/emmm.201708698] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
TIMM50 is an essential component of the TIM23 complex, the mitochondrial inner membrane machinery that imports cytosolic proteins containing a mitochondrial targeting presequence into the mitochondrial inner compartment. Whole exome sequencing (WES) identified compound heterozygous pathogenic mutations in TIMM50 in an infant patient with rapidly progressive, severe encephalopathy. Patient fibroblasts presented low levels of TIMM50 and other components of the TIM23 complex, lower mitochondrial membrane potential, and impaired TIM23-dependent protein import. As a consequence, steady-state levels of several components of mitochondrial respiratory chain were decreased, resulting in decreased respiration and increased ROS production. Growth of patient fibroblasts in galactose shifted energy production metabolism toward oxidative phosphorylation (OxPhos), producing an apparent improvement in most of the above features but also increased apoptosis. Complementation of patient fibroblasts with TIMM50 improved or restored these features to control levels. Moreover, RNASEH1 and ISCU mutant fibroblasts only shared a few of these features with TIMM50 mutant fibroblasts. Our results indicate that mutations in TIMM50 cause multiple mitochondrial bioenergetic dysfunction and that functional TIMM50 is essential for cell survival in OxPhos-dependent conditions.
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Affiliation(s)
- Aurelio Reyes
- MRC Mitochondrial Biology UnitUniversity of CambridgeCambridgeUK
| | - Laura Melchionda
- Unit of Molecular NeurogeneticsFoundation Carlo Besta Neurological Institute‐IRCCSMilanItaly
| | - Alberto Burlina
- Division of Inherited Metabolic DiseasesDepartment of PediatricsUniversity Hospital PadovaPadovaItaly
| | - Alan J Robinson
- MRC Mitochondrial Biology UnitUniversity of CambridgeCambridgeUK
| | - Daniele Ghezzi
- Unit of Molecular NeurogeneticsFoundation Carlo Besta Neurological Institute‐IRCCSMilanItaly
| | - Massimo Zeviani
- MRC Mitochondrial Biology UnitUniversity of CambridgeCambridgeUK
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14
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Fukasawa Y, Oda T, Tomii K, Imai K. Origin and Evolutionary Alteration of the Mitochondrial Import System in Eukaryotic Lineages. Mol Biol Evol 2017; 34:1574-1586. [PMID: 28369657 PMCID: PMC5455965 DOI: 10.1093/molbev/msx096] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Protein transport systems are fundamentally important for maintaining mitochondrial function. Nevertheless, mitochondrial protein translocases such as the kinetoplastid ATOM complex have recently been shown to vary in eukaryotic lineages. Various evolutionary hypotheses have been formulated to explain this diversity. To resolve any contradiction, estimating the primitive state and clarifying changes from that state are necessary. Here, we present more likely primitive models of mitochondrial translocases, specifically the translocase of the outer membrane (TOM) and translocase of the inner membrane (TIM) complexes, using scrutinized phylogenetic profiles. We then analyzed the translocases’ evolution in eukaryotic lineages. Based on those results, we propose a novel evolutionary scenario for diversification of the mitochondrial transport system. Our results indicate that presequence transport machinery was mostly established in the last eukaryotic common ancestor, and that primitive translocases already had a pathway for transporting presequence-containing proteins. Moreover, secondary changes including convergent and migrational gains of a presequence receptor in TOM and TIM complexes, respectively, likely resulted from constrained evolution. The nature of a targeting signal can constrain alteration to the protein transport complex.
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Affiliation(s)
- Yoshinori Fukasawa
- Artificial Intelligence Research Center, National Institute of Advanced Science and Technology (AIST), Tokyo, Japan
| | - Toshiyuki Oda
- Artificial Intelligence Research Center, National Institute of Advanced Science and Technology (AIST), Tokyo, Japan
| | - Kentaro Tomii
- Artificial Intelligence Research Center, National Institute of Advanced Science and Technology (AIST), Tokyo, Japan.,Biotechnology Research Institute for Drug Discovery, National Institute of Advanced Science and Technology (AIST), Tokyo, Japan
| | - Kenichiro Imai
- Artificial Intelligence Research Center, National Institute of Advanced Science and Technology (AIST), Tokyo, Japan.,Biotechnology Research Institute for Drug Discovery, National Institute of Advanced Science and Technology (AIST), Tokyo, Japan
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15
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Abstract
Mitochondria are essential organelles with numerous functions in cellular metabolism and homeostasis. Most of the >1,000 different mitochondrial proteins are synthesized as precursors in the cytosol and are imported into mitochondria by five transport pathways. The protein import machineries of the mitochondrial membranes and aqueous compartments reveal a remarkable variability of mechanisms for protein recognition, translocation, and sorting. The protein translocases do not operate as separate entities but are connected to each other and to machineries with functions in energetics, membrane organization, and quality control. Here, we discuss the versatility and dynamic organization of the mitochondrial protein import machineries. Elucidating the molecular mechanisms of mitochondrial protein translocation is crucial for understanding the integration of protein translocases into a large network that controls organelle biogenesis, function, and dynamics.
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Affiliation(s)
- Nils Wiedemann
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, and BIOSS Centre for Biological Signaling Studies, University of Freiburg, 79104 Freiburg, Germany; ,
| | - Nikolaus Pfanner
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, and BIOSS Centre for Biological Signaling Studies, University of Freiburg, 79104 Freiburg, Germany; ,
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16
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Schendzielorz AB, Schulz C, Lytovchenko O, Clancy A, Guiard B, Ieva R, van der Laan M, Rehling P. Two distinct membrane potential-dependent steps drive mitochondrial matrix protein translocation. J Cell Biol 2016; 216:83-92. [PMID: 28011846 PMCID: PMC5223606 DOI: 10.1083/jcb.201607066] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Revised: 09/30/2016] [Accepted: 11/28/2016] [Indexed: 12/03/2022] Open
Abstract
Schendzielorz et al. report that mitochondrial precursors display different dependencies on the membrane potential (Δψ) for translocation. Two distinct Δψ-dependent steps promote precursor translocation, the first driving presequence translocation and the second acting on the mature portion of the polypeptide chain. Two driving forces energize precursor translocation across the inner mitochondrial membrane. Although the membrane potential (Δψ) is considered to drive translocation of positively charged presequences through the TIM23 complex (presequence translocase), the activity of the Hsp70-powered import motor is crucial for the translocation of the mature protein portion into the matrix. In this study, we show that mitochondrial matrix proteins display surprisingly different dependencies on the Δψ. However, a precursor’s hypersensitivity to a reduction of the Δψ is not linked to the respective presequence, but rather to the mature portion of the polypeptide chain. The presequence translocase constituent Pam17 is specifically recruited by the receptor Tim50 to promote the transport of hypersensitive precursors into the matrix. Our analyses show that two distinct Δψ-driven translocation steps energize precursor passage across the inner mitochondrial membrane. The Δψ- and Pam17-dependent import step identified in this study is positioned between the two known energy-dependent steps: Δψ-driven presequence translocation and adenosine triphosphate–driven import motor activity.
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Affiliation(s)
- Alexander Benjamin Schendzielorz
- Department of Cellular Biochemistry, University Medical Center Göttingen, Georg-August-Universität Göttingen, 37073 Göttingen, Germany
| | - Christian Schulz
- Department of Cellular Biochemistry, University Medical Center Göttingen, Georg-August-Universität Göttingen, 37073 Göttingen, Germany
| | - Oleksandr Lytovchenko
- Department of Cellular Biochemistry, University Medical Center Göttingen, Georg-August-Universität Göttingen, 37073 Göttingen, Germany
| | - Anne Clancy
- Department of Molecular Biology, University Medical Center Göttingen, Georg-August-Universität Göttingen, 37073 Göttingen, Germany
| | - Bernard Guiard
- Centre de Génétique Moléculaire, Centre National de la Recherche Scientifique, 91190 Gif-sur-Yvette, France
| | - Raffaele Ieva
- Laboratoire de Microbiologie et Génétique Moléculaire, Centre de Biologie Intégrative, Université de Toulouse, Centre National de la Recherche Scientifique, Unité Propre de Service, 31062 Toulouse, France.,Institute of Biochemistry and Molecular Biology, Center for Biochemistry and Molecular Cell Research, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany
| | - Martin van der Laan
- Institute of Biochemistry and Molecular Biology, Center for Biochemistry and Molecular Cell Research, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany.,Medical Biochemistry and Molecular Biology, Saarland University, 66421 Homburg, Germany
| | - Peter Rehling
- Department of Cellular Biochemistry, University Medical Center Göttingen, Georg-August-Universität Göttingen, 37073 Göttingen, Germany .,Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
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17
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Garg SG, Gould SB. The Role of Charge in Protein Targeting Evolution. Trends Cell Biol 2016; 26:894-905. [PMID: 27524662 DOI: 10.1016/j.tcb.2016.07.001] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Revised: 06/28/2016] [Accepted: 07/11/2016] [Indexed: 12/31/2022]
Abstract
Two eukaryotic compartments are of endosymbiotic origin, the mitochondrion and plastid. These organelles need to import hundreds of proteins from the cytosol. The import machineries of both are of independent origin, but function in a similar fashion and recognize N-terminal targeting sequences that also share similarities. Targeting, however, is generally specific, even though plastid targeting evolved in the presence of established mitochondrial targeting. Here we review current advances on protein import into mitochondria and plastids from diverse eukaryotic lineages and highlight the impact of charged amino acids in targeting. Their presence or absence alone can determine localization, and comparisons across diverse eukaryotes, and their different types of mitochondria and plastids, uncover unexplored avenues of protein import research.
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Affiliation(s)
- Sriram G Garg
- Institute for Molecular Evolution, University of Düsseldorf, 40225 Düsseldorf, Germany
| | - Sven B Gould
- Institute for Molecular Evolution, University of Düsseldorf, 40225 Düsseldorf, Germany.
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