1
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Özdemir M, Dennerlein S. The TOM complex from an evolutionary perspective and the functions of TOMM70. Biol Chem 2024; 0:hsz-2024-0043. [PMID: 39092472 DOI: 10.1515/hsz-2024-0043] [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: 03/15/2024] [Accepted: 07/17/2024] [Indexed: 08/04/2024]
Abstract
In humans, up to 1,500 mitochondrial precursor proteins are synthesized at cytosolic ribosomes and must be imported into the organelle. This is not only essential for mitochondrial but also for many cytosolic functions. The majority of mitochondrial precursor proteins are imported over the translocase of the outer membrane (TOM). In recent years, high-resolution structure analyses from different organisms shed light on the composition and arrangement of the TOM complex. Although significant similarities have been found, differences were also observed, which have been favored during evolution and could reflect the manifold functions of TOM with cellular signaling and its response to altered metabolic situations. A key component within these regulatory mechanisms is TOMM70, which is involved in protein import, forms contacts to the ER and the nucleus, but is also involved in cellular defense mechanisms during infections.
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Affiliation(s)
- Metin Özdemir
- Institute for Cellular Biochemistry, University Medical Center Göttingen, Humboldtallee 23, D-37073 Göttingen, Germany
| | - Sven Dennerlein
- Institute for Cellular Biochemistry, University Medical Center Göttingen, Humboldtallee 23, D-37073 Göttingen, Germany
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2
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Raimi OG, Ojha H, Ehses K, Dederer V, Lange SM, Rivera CP, Deegan TD, Chen Y, Wightman M, Toth R, Labib KPM, Mathea S, Ranson N, Fernández-Busnadiego R, Muqit MMK. Mechanism of human PINK1 activation at the TOM complex in a reconstituted system. SCIENCE ADVANCES 2024; 10:eadn7191. [PMID: 38848361 PMCID: PMC11160474 DOI: 10.1126/sciadv.adn7191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/01/2024] [Accepted: 05/02/2024] [Indexed: 06/09/2024]
Abstract
Loss-of-function mutations in PTEN-induced kinase 1 (PINK1) are a frequent cause of early-onset Parkinson's disease (PD). Stabilization of PINK1 at the translocase of outer membrane (TOM) complex of damaged mitochondria is critical for its activation. The mechanism of how PINK1 is activated in the TOM complex is unclear. Here, we report that co-expression of human PINK1 and all seven TOM subunits in Saccharomyces cerevisiae is sufficient for PINK1 activation. We use this reconstitution system to systematically assess the role of each TOM subunit toward PINK1 activation. We unambiguously demonstrate that the TOM20 and TOM70 receptor subunits are required for optimal PINK1 activation and map their sites of interaction with PINK1 using AlphaFold structural modeling and mutagenesis. We also demonstrate an essential role of the pore-containing subunit TOM40 and its structurally associated subunits TOM7 and TOM22 for PINK1 activation. These findings will aid in the development of small-molecule activators of PINK1 as a therapeutic strategy for PD.
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Affiliation(s)
- Olawale G. Raimi
- MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Hina Ojha
- MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Kenneth Ehses
- Institute of Neuropathology, University Medical Center Göttingen, 37099 Göttingen, Germany
- Cluster of Excellence “Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells” (MBExC), University of Göttingen, Göttingen, Germany
| | - Verena Dederer
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA
- Institute of Pharmaceutical Chemistry, Goethe-Universität, 60438 Frankfurt, Germany
- Structural Genomics Consortium (SGC), Buchmann Institute for Life Sciences, Goethe-Universität, 60438 Frankfurt, Germany
| | - Sven M. Lange
- MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Cristian Polo Rivera
- MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Tom D. Deegan
- MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, Western General Hospital, Edinburgh EH4 2XU, UK
| | - Yinchen Chen
- MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Melanie Wightman
- MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Rachel Toth
- MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Karim P. M. Labib
- MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Sebastian Mathea
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA
- Institute of Pharmaceutical Chemistry, Goethe-Universität, 60438 Frankfurt, Germany
- Structural Genomics Consortium (SGC), Buchmann Institute for Life Sciences, Goethe-Universität, 60438 Frankfurt, Germany
| | - Neil Ranson
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Rubén Fernández-Busnadiego
- Institute of Neuropathology, University Medical Center Göttingen, 37099 Göttingen, Germany
- Cluster of Excellence “Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells” (MBExC), University of Göttingen, Göttingen, Germany
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA
- Faculty of Physics, University of Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
| | - Miratul M. K. Muqit
- MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA
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3
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Nussberger S, Ghosh R, Wang S. New insights into the structure and dynamics of the TOM complex in mitochondria. Biochem Soc Trans 2024; 52:911-922. [PMID: 38629718 PMCID: PMC11088910 DOI: 10.1042/bst20231236] [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: 02/13/2024] [Revised: 03/21/2024] [Accepted: 04/03/2024] [Indexed: 04/25/2024]
Abstract
To date, there is no general physical model of the mechanism by which unfolded polypeptide chains with different properties are imported into the mitochondria. At the molecular level, it is still unclear how transit polypeptides approach, are captured by the protein translocation machinery in the outer mitochondrial membrane, and how they subsequently cross the entropic barrier of a protein translocation pore to enter the intermembrane space. This deficiency has been due to the lack of detailed structural and dynamic information about the membrane pores. In this review, we focus on the recently determined sub-nanometer cryo-EM structures and our current knowledge of the dynamics of the mitochondrial two-pore outer membrane protein translocation machinery (TOM core complex), which provide a starting point for addressing the above questions. Of particular interest are recent discoveries showing that the TOM core complex can act as a mechanosensor, where the pores close as a result of interaction with membrane-proximal structures. We highlight unusual and new correlations between the structural elements of the TOM complexes and their dynamic behavior in the membrane environment.
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Affiliation(s)
- Stephan Nussberger
- Department of Biophysics, Institute of Biomaterials and Biomolecular Systems, University of Stuttgart, Stuttgart, Germany
| | - Robin Ghosh
- Department of Bioenergetics, Institute of Biomaterials and Biomolecular Systems, University of Stuttgart, Stuttgart, Germany
| | - Shuo Wang
- Department of Biophysics, Institute of Biomaterials and Biomolecular Systems, University of Stuttgart, Stuttgart, Germany
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4
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Ornelas P, Bausewein T, Martin J, Morgner N, Nussberger S, Kühlbrandt W. Two conformations of the Tom20 preprotein receptor in the TOM holo complex. Proc Natl Acad Sci U S A 2023; 120:e2301447120. [PMID: 37579144 PMCID: PMC10450662 DOI: 10.1073/pnas.2301447120] [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: 01/30/2023] [Accepted: 07/17/2023] [Indexed: 08/16/2023] Open
Abstract
The TOM complex is the main entry point for precursor proteins (preproteins) into mitochondria. Preproteins containing targeting sequences are recognized by the TOM complex and imported into mitochondria. We have determined the structure of the TOM core complex from Neurospora crassa by single-particle electron cryomicroscopy at 3.3 Å resolution, showing its interaction with a bound preprotein at 4 Å resolution, and of the TOM holo complex including the Tom20 receptor at 6 to 7 Å resolution. TOM is a transmembrane complex consisting of two β-barrels, three receptor subunits, and three short transmembrane subunits. Tom20 has a transmembrane helix and a receptor domain on the cytoplasmic side. We propose that Tom20 acts as a dynamic gatekeeper, guiding preproteins into the pores of the TOM complex. We analyze the interactions of Tom20 with other TOM subunits, present insights into the structure of the TOM holo complex, and suggest a translocation mechanism.
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Affiliation(s)
- Pamela Ornelas
- Department of Structural Biology, Max-Planck-Institute of Biophysics, Frankfurt60438, Germany
| | - Thomas Bausewein
- Department of Structural Biology, Max-Planck-Institute of Biophysics, Frankfurt60438, Germany
| | - Janosch Martin
- Department of Structural Biology, Institute of Physical and Theoretical Chemistry, Goethe University of Frankfurt, Frankfurt60439, Germany
| | - Nina Morgner
- Department of Structural Biology, Institute of Physical and Theoretical Chemistry, Goethe University of Frankfurt, Frankfurt60439, Germany
| | - Stephan Nussberger
- Department of Biophysics, Institute of Biomaterials and Biomolecular Systems, University of Stuttgart, Stuttgart70569, Germany
| | - Werner Kühlbrandt
- Department of Structural Biology, Max-Planck-Institute of Biophysics, Frankfurt60438, Germany
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5
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Deragon MA, McCaig WD, Truong PV, Metz KR, Carron KA, Hughes KJ, Knapp AR, Dougherty MJ, LaRocca TJ. Mitochondrial Trafficking of MLKL, Bak/Bax, and Drp1 Is Mediated by RIP1 and ROS which Leads to Decreased Mitochondrial Membrane Integrity during the Hyperglycemic Shift to Necroptosis. Int J Mol Sci 2023; 24:ijms24108609. [PMID: 37239951 DOI: 10.3390/ijms24108609] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Revised: 05/04/2023] [Accepted: 05/08/2023] [Indexed: 05/28/2023] Open
Abstract
Apoptosis and necroptosis overlap in their initial signaling but diverge to produce non-inflammatory and pro-inflammatory outcomes, respectively. High glucose pushes signaling in favor of necroptosis producing a hyperglycemic shift from apoptosis to necroptosis. This shift depends on receptor-interacting protein 1 (RIP1) and mitochondrial reactive oxygen species (ROS). Here, we show that RIP1, mixed lineage kinase domain-like (MLKL) protein, Bcl-2 agonist/killer (Bak), Bcl-2 associated x (Bax) protein, and dynamin-related protein 1 (Drp1) traffic to the mitochondria in high glucose. RIP1 and MLKL appear in the mitochondria in their activated, phosphorylated states while Drp1 appears in its activated, dephosphorylated state in high glucose. Mitochondrial trafficking is prevented in rip1 KO cells and upon treatment with N-acetylcysteine. Induction of ROS replicated the mitochondrial trafficking seen in high glucose. MLKL forms high MW oligomers in the outer and inner mitochondrial membranes while Bak and Bax form high MW oligomers in the outer mitochondrial membrane in high glucose, suggesting pore formation. MLKL, Bax, and Drp1 promoted cytochrome c release from the mitochondria as well as a decrease in mitochondrial membrane potential in high glucose. These results indicate that mitochondrial trafficking of RIP1, MLKL, Bak, Bax, and Drp1 are key events in the hyperglycemic shift from apoptosis to necroptosis. This is also the first report to show oligomerization of MLKL in the inner and outer mitochondrial membranes and dependence of mitochondrial permeability on MLKL.
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Affiliation(s)
- Matthew A Deragon
- Department of Basic and Clinical Sciences, Albany College of Pharmacy and Health Sciences, Albany, NY 12208, USA
| | - William D McCaig
- Department of Basic and Clinical Sciences, Albany College of Pharmacy and Health Sciences, Albany, NY 12208, USA
| | - Phillip V Truong
- Department of Basic and Clinical Sciences, Albany College of Pharmacy and Health Sciences, Albany, NY 12208, USA
| | - Kevin R Metz
- Department of Basic and Clinical Sciences, Albany College of Pharmacy and Health Sciences, Albany, NY 12208, USA
| | - Katherine A Carron
- Department of Basic and Clinical Sciences, Albany College of Pharmacy and Health Sciences, Albany, NY 12208, USA
| | - Keven J Hughes
- Department of Basic and Clinical Sciences, Albany College of Pharmacy and Health Sciences, Albany, NY 12208, USA
| | - Angeleigh R Knapp
- Department of Basic and Clinical Sciences, Albany College of Pharmacy and Health Sciences, Albany, NY 12208, USA
| | - Molly J Dougherty
- Department of Basic and Clinical Sciences, Albany College of Pharmacy and Health Sciences, Albany, NY 12208, USA
| | - Timothy J LaRocca
- Department of Basic and Clinical Sciences, Albany College of Pharmacy and Health Sciences, Albany, NY 12208, USA
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6
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Li Z, Zhang Y, Tian F, Wang Z, Song H, Chen H, Wu B. Omentin-1 promotes mitochondrial biogenesis via PGC1α-AMPK pathway in chondrocytes. Arch Physiol Biochem 2023; 129:291-297. [PMID: 32930026 DOI: 10.1080/13813455.2020.1819337] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
OBJECTIVE Omentin-1 is a newly discovered metabolic regulatory adipokine. Studies have shown that omentin-1 possesses pleiotropic effects in different types of cells. This study aims to investigate the regulation by omentin-1 on mitochondrial biogenesis in chondrocytes. METHODOLOGY C-28/I2 chondrocytes were treated with omentin-1 (150 and 300 ng/ml) for 24 h. The expression of mitochondrial regulators, markers and the DNA copy was assessed. The mitochondrial morphology was observed by electron microscopy. The mitochondrial respiratory rate and ATP production in chondrocytes were measured by cell lysates. RESULTS Omentin-1 treatment up-regulated PGC-1α, NRF-1 and mitochondrial transcription factor A (TFAM) in cultured chondrocytes, indicating that omentin-1 could be involved in the regulation of mitochondrial function. Omentin-1 promoted mtDNA/nDNA and four mitochondrial genes (Tomm20, Tomm40, Timm9 and Atp5c1), mRNA transcripts as well as two mitochondrial protein expressions (SDHB and MTCO1). At a cellular level, omentin-1 enhanced the mitochondrial respiratory rate and ATP production. Mechanistically, we proved that omentin-1 increased AMPKα activation, and the blockage of AMPKα by its inhibitor compound C abolished the inductive effect of omentin-1 on PGC1α expression and mtDNA/nDNA ratio, indicating that the effect of omentin-1 is dependent on AMPKα activation. CONCLUSION Omentin-1 is a positive regulator of mitochondrial biogenesis in chondrocytes, and its action is dependent on the AMPK-PGC1α pathway. This study, therefore, implies that omentin-1 has the potential to remedy chondrocyte damage in the prevention and treatment of osteoarthritis.
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Affiliation(s)
- Zhigang Li
- Department of Orthopaedics, Affiliated Zhongshan Hospital of Dalian University, Dalian, Liaoning, China
| | - Yao Zhang
- Department of Orthopaedics, Affiliated Zhongshan Hospital of Dalian University, Dalian, Liaoning, China
| | - Fengde Tian
- Department of Orthopaedics, Affiliated Zhongshan Hospital of Dalian University, Dalian, Liaoning, China
| | - Zihua Wang
- Department of Orthopaedics, Affiliated Zhongshan Hospital of Dalian University, Dalian, Liaoning, China
| | - Haiyang Song
- Department of Orthopaedics, Affiliated Zhongshan Hospital of Dalian University, Dalian, Liaoning, China
| | - Haojie Chen
- Department of Orthopaedics, Affiliated Zhongshan Hospital of Dalian University, Dalian, Liaoning, China
| | - Baolin Wu
- Department of Orthopaedics, Affiliated Zhongshan Hospital of Dalian University, Dalian, Liaoning, China
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7
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Spatiotemporal stop-and-go dynamics of the mitochondrial TOM core complex correlates with channel activity. Commun Biol 2022; 5:471. [PMID: 35581327 PMCID: PMC9114391 DOI: 10.1038/s42003-022-03419-4] [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] [Received: 12/02/2021] [Accepted: 04/26/2022] [Indexed: 11/08/2022] Open
Abstract
Single-molecule studies can reveal phenomena that remain hidden in ensemble measurements. Here we show the correlation between lateral protein diffusion and channel activity of the general protein import pore of mitochondria (TOM-CC) in membranes resting on ultrathin hydrogel films. Using electrode-free optical recordings of ion flux, we find that TOM-CC switches reversibly between three states of ion permeability associated with protein diffusion. While freely diffusing TOM-CC molecules are predominantly in a high permeability state, non-mobile molecules are mostly in an intermediate or low permeability state. We explain this behavior by the mechanical binding of the two protruding Tom22 subunits to the hydrogel and a concomitant combinatorial opening and closing of the two β-barrel pores of TOM-CC. TOM-CC could thus represent a β-barrel membrane protein complex to exhibit membrane state-dependent mechanosensitive properties, mediated by its two Tom22 subunits.
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8
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Sayyed UMH, Mahalakshmi R. Mitochondrial protein translocation machinery: From TOM structural biogenesis to functional regulation. J Biol Chem 2022; 298:101870. [PMID: 35346689 PMCID: PMC9052162 DOI: 10.1016/j.jbc.2022.101870] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2021] [Revised: 03/13/2022] [Accepted: 03/14/2022] [Indexed: 01/15/2023] Open
Abstract
The human mitochondrial outer membrane is biophysically unique as it is the only membrane possessing transmembrane β-barrel proteins (mitochondrial outer membrane proteins, mOMPs) in the cell. The most vital of the three mOMPs is the core protein of the translocase of the outer mitochondrial membrane (TOM) complex. Identified first as MOM38 in Neurospora in 1990, the structure of Tom40, the core 19-stranded β-barrel translocation channel, was solved in 2017, after nearly three decades. Remarkably, the past four years have witnessed an exponential increase in structural and functional studies of yeast and human TOM complexes. In addition to being conserved across all eukaryotes, the TOM complex is the sole ATP-independent import machinery for nearly all of the ∼1000 to 1500 known mitochondrial proteins. Recent cryo-EM structures have provided detailed insight into both possible assembly mechanisms of the TOM core complex and organizational dynamics of the import machinery and now reveal novel regulatory interplay with other mOMPs. Functional characterization of the TOM complex using biochemical and structural approaches has also revealed mechanisms for substrate recognition and at least five defined import pathways for precursor proteins. In this review, we discuss the discovery, recently solved structures, molecular function, and regulation of the TOM complex and its constituents, along with the implications these advances have for alleviating human diseases.
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Affiliation(s)
- Ulfat Mohd Hanif Sayyed
- Molecular Biophysics Laboratory, Indian Institute of Science Education and Research, Bhopal, India
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9
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Araiso Y, Imai K, Endo T. Role of the TOM Complex in Protein Import into Mitochondria: Structural Views. Annu Rev Biochem 2022; 91:679-703. [PMID: 35287471 DOI: 10.1146/annurev-biochem-032620-104527] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Mitochondria are central to energy production, metabolism and signaling, and apoptosis. To make new mitochondria from preexisting mitochondria, the cell needs to import mitochondrial proteins from the cytosol into the mitochondria with the aid of translocators in the mitochondrial membranes. The translocase of the outer membrane (TOM) complex, an outer membrane translocator, functions as an entry gate for most mitochondrial proteins. Although high-resolution structures of the receptor subunits of the TOM complex were deposited in the early 2000s, those of entire TOM complexes became available only in 2019. The structural details of these TOM complexes, consisting of the dimer of the β-barrel import channel Tom40 and four α-helical membrane proteins, revealed the presence of several distinct paths and exits for the translocation of over 1,000 different mitochondrial precursor proteins. High-resolution structures of TOM complexes now open up a new era of studies on the structures, functions, and dynamics of the mitochondrial import system. Expected final online publication date for the Annual Review of Biochemistry, Volume 91 is June 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Yuhei Araiso
- Department of Clinical Laboratory Science, Division of Health Sciences, Graduate School of Medical Science, Kanazawa University, Kanazawa, Ishikawa, Japan
| | - Kenichiro Imai
- Cellular and Molecular Biotechnology Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tokyo, Japan
| | - Toshiya Endo
- Faculty of Life Sciences, Kyoto Sangyo University, Kyoto, Japan; .,Institute for Protein Dynamics, Kyoto Sangyo University, Kyoto, Japan
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10
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Bhagawati M, Arroum T, Webeling N, Montoro AG, Mootz HD, Busch KB. The receptor subunit Tom20 is dynamically associated with the TOM complex in mitochondria of human cells. Mol Biol Cell 2021; 32:br1. [PMID: 34347503 PMCID: PMC8684756 DOI: 10.1091/mbc.e21-01-0042] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022] Open
Abstract
The outer membrane translocase (TOM) is the import channel for nuclear-encoded mitochondrial proteins. The general import pore contains Tom40, Tom22, Tom5, Tom6, and Tom7. Precursor proteins are bound by the (peripheral) receptor proteins Tom20, Tom22, and Tom70 before being imported by the TOM complex. Here we investigated the association of the receptor Tom20 with the TOM complex. Tom20 was found in the TOM complex, but not in a smaller subcomplex. In addition, a subcomplex was found without Tom40 and Tom7 but with Tom20. Using single particle tracking of labeled Tom20 in overexpressing human cells, we show that Tom20 has, on average, higher lateral mobility in the membrane than Tom7/TOM. After ligation of Tom20 with the TOM complex by post-tranlational protein trans-splicing using the traceless, ultrafast cleaved Gp41-1 integrin system, a significant decrease in the mean diffusion coefficient of Tom20 was observed in the resulting Tom20–Tom7 fusion protein. Exposure of Tom20 to high substrate loading also resulted in reduced mobility. Taken together, our data show that the receptor subunit Tom20 interacts dynamically with the TOM core complex. We suggest that the TOM complex containing Tom20 is the active import pore and that Tom20 is associated when substrate is available.
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Affiliation(s)
- Maniraj Bhagawati
- Department of Biology, Institute of Molecular Cell Biology, University of Münster, Schloßplatz 5, 48149 Münster (Germany).,Department of Chemistry and Pharmacy, Institute of Biochemistry, University of Münster, Corrensstraße 36, 48149 Münster (Germany).,Center of Cellular Nanoanalytics Osnabrück, 49076 Osnabrück (Germany)
| | - Tasnim Arroum
- Department of Biology, Institute of Molecular Cell Biology, University of Münster, Schloßplatz 5, 48149 Münster (Germany)
| | - Niklas Webeling
- Department of Biology, Institute of Molecular Cell Biology, University of Münster, Schloßplatz 5, 48149 Münster (Germany)
| | - Ayelén González Montoro
- Center of Cellular Nanoanalytics Osnabrück, 49076 Osnabrück (Germany).,Cellular communication laboratoraty, Department of Biology and Chemistry, University of Osnabrueck, Barbarastraße 13, 49076 Osnabrueck (Germany)
| | - Henning D Mootz
- Department of Chemistry and Pharmacy, Institute of Biochemistry, University of Münster, Corrensstraße 36, 48149 Münster (Germany)
| | - Karin B Busch
- Department of Biology, Institute of Molecular Cell Biology, University of Münster, Schloßplatz 5, 48149 Münster (Germany)
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11
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The Diversity of the Mitochondrial Outer Membrane Protein Import Channels: Emerging Targets for Modulation. Molecules 2021; 26:molecules26134087. [PMID: 34279427 PMCID: PMC8272145 DOI: 10.3390/molecules26134087] [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: 06/04/2021] [Revised: 06/30/2021] [Accepted: 07/01/2021] [Indexed: 12/21/2022] Open
Abstract
The functioning of mitochondria and their biogenesis are largely based on the proper function of the mitochondrial outer membrane channels, which selectively recognise and import proteins but also transport a wide range of other molecules, including metabolites, inorganic ions and nucleic acids. To date, nine channels have been identified in the mitochondrial outer membrane of which at least half represent the mitochondrial protein import apparatus. When compared to the mitochondrial inner membrane, the presented channels are mostly constitutively open and consequently may participate in transport of different molecules and contribute to relevant changes in the outer membrane permeability based on the channel conductance. In this review, we focus on the channel structure, properties and transported molecules as well as aspects important to their modulation. This information could be used for future studies of the cellular processes mediated by these channels, mitochondrial functioning and therapies for mitochondria-linked diseases.
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12
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Grevel A, Becker T. Porins as helpers in mitochondrial protein translocation. Biol Chem 2021; 401:699-708. [PMID: 31967957 DOI: 10.1515/hsz-2019-0438] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Accepted: 01/15/2020] [Indexed: 12/22/2022]
Abstract
Mitochondria import the vast majority of their proteins via dedicated protein machineries. The translocase of the outer membrane (TOM complex) forms the main entry site for precursor proteins that are produced on cytosolic ribosomes. Subsequently, different protein sorting machineries transfer the incoming preproteins to the mitochondrial outer and inner membranes, the intermembrane space, and the matrix. In this review, we highlight the recently discovered role of porin, also termed voltage-dependent anion channel (VDAC), in mitochondrial protein biogenesis. Porin forms the major channel for metabolites and ions in the outer membrane of mitochondria. Two different functions of porin in protein translocation have been reported. First, it controls the formation of the TOM complex by modulating the integration of the central receptor Tom22 into the mature translocase. Second, porin promotes the transport of carrier proteins toward the carrier translocase (TIM22 complex), which inserts these preproteins into the inner membrane. Therefore, porin acts as a coupling factor to spatially coordinate outer and inner membrane transport steps. Thus, porin links metabolite transport to protein import, which are both essential for mitochondrial function and biogenesis.
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Affiliation(s)
- Alexander Grevel
- Institute of Biochemistry und Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany.,Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany
| | - Thomas Becker
- Institute of Biochemistry und Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany.,CIBSS Centre for Integrative Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany
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13
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Bausewein T, Naveed H, Liang J, Nussberger S. The structure of the TOM core complex in the mitochondrial outer membrane. Biol Chem 2021; 401:687-697. [PMID: 32142473 DOI: 10.1515/hsz-2020-0104] [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: 01/05/2020] [Accepted: 03/03/2020] [Indexed: 02/05/2023]
Abstract
In the past three decades, significant advances have been made in providing the biochemical background of TOM (translocase of the outer mitochondrial membrane)-mediated protein translocation into mitochondria. In the light of recent cryoelectron microscopy-derived structures of TOM isolated from Neurospora crassa and Saccharomyces cerevisiae, the interpretation of biochemical and biophysical studies of TOM-mediated protein transport into mitochondria now rests on a solid basis. In this review, we compare the subnanometer structure of N. crassa TOM core complex with that of yeast. Both structures reveal remarkably well-conserved symmetrical dimers of 10 membrane protein subunits. The structural data also validate predictions of weakly stable regions in the transmembrane β-barrel domains of the protein-conducting subunit Tom40, which signal the existence of β-strands located in interfaces of protein-protein interactions.
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Affiliation(s)
- Thomas Bausewein
- Max-Planck-Institute of Biophysics, Department of Structural Biology, Max-von-Laue-Str. 3, D-60438Frankfurt am Main, Germany
| | - Hammad Naveed
- National University of Computer and Emerging Sciences, Department of Computer Science, A. K. Brohi Road H-11/4, Islamabad 44000, Pakistan
| | - Jie Liang
- Richard and Loan Hill Department of Bioengineering, MC-063, University of Illinois, Chicago, IL 60607-7052, USA
| | - Stephan Nussberger
- University of Stuttgart, Institute of Biomaterials and Biomolecular Systems, Department of Biophysics, Pfaffenwaldring 57, D-70569Stuttgart, Germany
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14
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Guan Z, Yan L, Wang Q, Qi L, Hong S, Gong Z, Yan C, Yin P. Structural insights into assembly of human mitochondrial translocase TOM complex. Cell Discov 2021; 7:22. [PMID: 33846286 PMCID: PMC8041818 DOI: 10.1038/s41421-021-00252-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 02/16/2021] [Indexed: 11/10/2022] Open
Affiliation(s)
- Zeyuan Guan
- National Key Laboratory of Crop Genetic Improvement and National Centre of Plant Gene Research, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Ling Yan
- National Key Laboratory of Crop Genetic Improvement and National Centre of Plant Gene Research, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Qiang Wang
- National Key Laboratory of Crop Genetic Improvement and National Centre of Plant Gene Research, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Liangbo Qi
- National Key Laboratory of Crop Genetic Improvement and National Centre of Plant Gene Research, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Sixing Hong
- National Key Laboratory of Crop Genetic Improvement and National Centre of Plant Gene Research, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Zhou Gong
- Laboratory of Magnetic Resonance and Atomic Molecular Physics, Wuhan Institute of Physics and Mathematics of the Chinese Academy of Sciences, Wuhan, Hubei, 430071, China
| | - Chuangye Yan
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, 100084, China.
| | - Ping Yin
- National Key Laboratory of Crop Genetic Improvement and National Centre of Plant Gene Research, Huazhong Agricultural University, Wuhan, Hubei, 430070, China.
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15
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Grevel A, Pfanner N, Becker T. Coupling of import and assembly pathways in mitochondrial protein biogenesis. Biol Chem 2020; 401:117-129. [PMID: 31513529 DOI: 10.1515/hsz-2019-0310] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2019] [Accepted: 08/13/2019] [Indexed: 12/14/2022]
Abstract
Biogenesis and function of mitochondria depend on the import of about 1000 precursor proteins that are produced on cytosolic ribosomes. The translocase of the outer membrane (TOM) forms the entry gate for most proteins. After passage through the TOM channel, dedicated preprotein translocases sort the precursor proteins into the mitochondrial subcompartments. Many proteins have to be assembled into oligomeric membrane-integrated complexes in order to perform their functions. In this review, we discuss a dual role of mitochondrial preprotein translocases in protein translocation and oligomeric assembly, focusing on the biogenesis of the TOM complex and the respiratory chain. The sorting and assembly machinery (SAM) of the outer mitochondrial membrane forms a dynamic platform for coupling transport and assembly of TOM subunits. The biogenesis of the cytochrome c oxidase of the inner membrane involves a molecular circuit to adjust translation of mitochondrial-encoded core subunits to the availability of nuclear-encoded partner proteins. Thus, mitochondrial protein translocases not only import precursor proteins but can also support their assembly into functional complexes.
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Affiliation(s)
- Alexander Grevel
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, D-79104 Freiburg, Germany.,Faculty of Biology, University of Freiburg, D-79104 Freiburg, Germany
| | - Nikolaus Pfanner
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, D-79104 Freiburg, Germany.,CIBSS Centre for Integrative Biological Signalling Studies, University of Freiburg, D-79104 Freiburg, Germany
| | - Thomas Becker
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, D-79104 Freiburg, Germany.,CIBSS Centre for Integrative Biological Signalling Studies, University of Freiburg, D-79104 Freiburg, Germany
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16
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He H, Guo J, Lin X, Xu B. Enzyme-Instructed Assemblies Enable Mitochondria Localization of Histone H2B in Cancer Cells. Angew Chem Int Ed Engl 2020; 59:9330-9334. [PMID: 32119754 PMCID: PMC7269854 DOI: 10.1002/anie.202000983] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2020] [Indexed: 01/11/2023]
Abstract
Presently, little is known of how the inter-organelle crosstalk impacts cancer cells owing to the lack of approaches that can manipulate inter-organelle communication in cancer cells. We found that a negatively charged, enzyme cleavable peptide (MitoFlag) enables the trafficking of histone protein H2B, a nuclear protein, to the mitochondria in cancer cells. MitoFlag interacts with the nuclear location sequence of H2B to block it from entering the nucleus. A protease on the mitochondria cleaves the Flag from the MitoFlag/H2B complex to form assemblies that retain H2B on the mitochondria and facilitate H2B entering the mitochondria. Adding NLS, replacing aspartic acid by glutamic acid residues, or changing the l- to d-aspartic acid residue on MitoFlag abolishes the trafficking of H2B into mitochondria of HeLa cells. As the first example of the enzyme-instructed self-assembly of a synthetic peptide for trafficking endogenous proteins, this work provides insights for understanding and manipulating inter-organelle communication in cells.
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Affiliation(s)
- Hongjian He
- Department of Chemistry, Brandeis University, 415 South Street, Waltham, MA 02453, USA
| | - Jiaqi Guo
- Department of Chemistry, Brandeis University, 415 South Street, Waltham, MA 02453, USA
| | - Xingyi Lin
- Department of Chemistry, Brandeis University, 415 South Street, Waltham, MA 02453, USA
| | - Bing Xu
- Department of Chemistry, Brandeis University, 415 South Street, Waltham, MA 02453, USA
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He H, Guo J, Lin X, Xu B. Enzyme‐Instructed Assemblies Enable Mitochondria Localization of Histone H2B in Cancer Cells. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202000983] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Hongjian He
- Department of Chemistry Brandeis University 415 South Street Waltham MA 02453 USA
| | - Jiaqi Guo
- Department of Chemistry Brandeis University 415 South Street Waltham MA 02453 USA
| | - Xinyi Lin
- Department of Chemistry Brandeis University 415 South Street Waltham MA 02453 USA
| | - Bing Xu
- Department of Chemistry Brandeis University 415 South Street Waltham MA 02453 USA
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18
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Multifaceted roles of porin in mitochondrial protein and lipid transport. Biochem Soc Trans 2020; 47:1269-1277. [PMID: 31670371 DOI: 10.1042/bst20190153] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Revised: 10/03/2019] [Accepted: 10/04/2019] [Indexed: 11/17/2022]
Abstract
Mitochondria are essential eukaryotic organelles responsible for primary cellular energy production. Biogenesis, maintenance, and functions of mitochondria require correct assembly of resident proteins and lipids, which require their transport into and within mitochondria. Mitochondrial normal functions also require an exchange of small metabolites between the cytosol and mitochondria, which is primarily mediated by a metabolite channel of the outer membrane (OM) called porin or voltage-dependent anion channel. Here, we describe recently revealed novel roles of porin in the mitochondrial protein and lipid transport. First, porin regulates the formation of the mitochondrial protein import gate in the OM, the translocase of the outer membrane (TOM) complex, and its dynamic exchange between the major form of a trimer and the minor form of a dimer. The TOM complex dimer lacks a core subunit Tom22 and mediates the import of a subset of mitochondrial proteins while the TOM complex trimer facilitates the import of most other mitochondrial proteins. Second, porin interacts with both a translocating inner membrane (IM) protein like a carrier protein accumulated at the small TIM chaperones in the intermembrane space and the TIM22 complex, a downstream translocator in the IM for the carrier protein import. Porin thereby facilitates the efficient transfer of carrier proteins to the IM during their import. Third, porin facilitates the transfer of lipids between the OM and IM and promotes a back-up pathway for the cardiolipin synthesis in mitochondria. Thus, porin has roles more than the metabolite transport in the protein and lipid transport into and within mitochondria, which is likely conserved from yeast to human.
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Tucker K, Park E. Cryo-EM structure of the mitochondrial protein-import channel TOM complex at near-atomic resolution. Nat Struct Mol Biol 2019; 26:1158-1166. [PMID: 31740857 DOI: 10.1038/s41594-019-0339-2] [Citation(s) in RCA: 111] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Accepted: 10/23/2019] [Indexed: 11/09/2022]
Abstract
Nearly all mitochondrial proteins are encoded by the nuclear genome and imported into mitochondria after synthesis on cytosolic ribosomes. These precursor proteins are translocated into mitochondria by the TOM complex, a protein-conducting channel in the mitochondrial outer membrane. We have determined high-resolution cryo-EM structures of the core TOM complex from Saccharomyces cerevisiae in dimeric and tetrameric forms. Dimeric TOM consists of two copies each of five proteins arranged in two-fold symmetry: pore-forming β-barrel protein Tom40 and four auxiliary α-helical transmembrane proteins. The pore of each Tom40 has an overall negatively charged inner surface attributed to multiple functionally important acidic patches. The tetrameric complex is essentially a dimer of dimeric TOM, which may be capable of forming higher-order oligomers. Our study reveals the detailed molecular organization of the TOM complex and provides new insights about the mechanism of protein translocation into mitochondria.
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Affiliation(s)
- Kyle Tucker
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
| | - Eunyong Park
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA. .,California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, CA, USA.
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20
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Structure of the mitochondrial import gate reveals distinct preprotein paths. Nature 2019; 575:395-401. [PMID: 31600774 DOI: 10.1038/s41586-019-1680-7] [Citation(s) in RCA: 135] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2019] [Accepted: 09/30/2019] [Indexed: 11/08/2022]
Abstract
The translocase of the outer mitochondrial membrane (TOM) is the main entry gate for proteins1-4. Here we use cryo-electron microscopy to report the structure of the yeast TOM core complex5-9 at 3.8-Å resolution. The structure reveals the high-resolution architecture of the translocator consisting of two Tom40 β-barrel channels and α-helical transmembrane subunits, providing insight into critical features that are conserved in all eukaryotes1-3. Each Tom40 β-barrel is surrounded by small TOM subunits, and tethered by two Tom22 subunits and one phospholipid. The N-terminal extension of Tom40 forms a helix inside the channel; mutational analysis reveals its dual role in early and late steps in the biogenesis of intermembrane-space proteins in cooperation with Tom5. Each Tom40 channel possesses two precursor exit sites. Tom22, Tom40 and Tom7 guide presequence-containing preproteins to the exit in the middle of the dimer, whereas Tom5 and the Tom40 N extension guide preproteins lacking a presequence to the exit at the periphery of the dimer.
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21
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Bausewein T, Nussberger S, Kühlbrandt W. Cryo-EM structure of Neurospora crassa respiratory complex IV. IUCRJ 2019; 6:773-780. [PMID: 31316820 PMCID: PMC6608615 DOI: 10.1107/s2052252519007486] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Accepted: 05/23/2019] [Indexed: 05/13/2023]
Abstract
In fungi, the mitochondrial respiratory chain complexes (complexes I-IV) are responsible for oxidative phosphorylation, as in higher eukaryotes. Cryo-EM was used to identify a 200 kDa membrane protein from Neurospora crassa in lipid nanodiscs as cytochrome c oxidase (complex IV) and its structure was determined at 5.5 Å resolution. The map closely resembles the cryo-EM structure of complex IV from Saccharomyces cerevisiae. Its ten subunits are conserved in S. cerevisiae and Bos taurus, but other transmembrane subunits are missing. The different structure of the Cox5a subunit is typical for fungal complex IV and may affect the interaction with complex III in a respiratory supercomplex. Additional density was found between the matrix domains of the Cox4 and Cox5a subunits that appears to be specific to N. crassa.
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Affiliation(s)
- Thomas Bausewein
- Department of Structural Biology, Max-Planck-Institute of Biophysics, Max-von-Laue-Strasse 3, 60438 Frankfurt am Main, Germany
| | - Stephan Nussberger
- Abteilung Biophysik, Institut für Biomaterialien und biomolekulare Systeme, Universität Stuttgart, Pfaffenwaldring 57, 70550 Stuttgart, Germany
| | - Werner Kühlbrandt
- Department of Structural Biology, Max-Planck-Institute of Biophysics, Max-von-Laue-Strasse 3, 60438 Frankfurt am Main, Germany
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22
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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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23
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Makki A, Rada P, Žárský V, Kereïche S, Kováčik L, Novotný M, Jores T, Rapaport D, Tachezy J. Triplet-pore structure of a highly divergent TOM complex of hydrogenosomes in Trichomonas vaginalis. PLoS Biol 2019; 17:e3000098. [PMID: 30608924 PMCID: PMC6334971 DOI: 10.1371/journal.pbio.3000098] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Revised: 01/16/2019] [Accepted: 12/11/2018] [Indexed: 11/30/2022] Open
Abstract
Mitochondria originated from proteobacterial endosymbionts, and their transition to organelles was tightly linked to establishment of the protein import pathways. The initial import of most proteins is mediated by the translocase of the outer membrane (TOM). Although TOM is common to all forms of mitochondria, an unexpected diversity of subunits between eukaryotic lineages has been predicted. However, experimental knowledge is limited to a few organisms, and so far, it remains unsettled whether the triplet-pore or the twin-pore structure is the generic form of TOM complex. Here, we analysed the TOM complex in hydrogenosomes, a metabolically specialised anaerobic form of mitochondria found in the excavate Trichomonas vaginalis. We demonstrate that the highly divergent β-barrel T. vaginalis TOM (TvTom)40-2 forms a translocation channel to conduct hydrogenosomal protein import. TvTom40-2 is present in high molecular weight complexes, and their analysis revealed the presence of four tail-anchored (TA) proteins. Two of them, Tom36 and Tom46, with heat shock protein (Hsp)20 and tetratricopeptide repeat (TPR) domains, can bind hydrogenosomal preproteins and most likely function as receptors. A third subunit, Tom22-like protein, has a short cis domain and a conserved Tom22 transmembrane segment but lacks a trans domain. The fourth protein, hydrogenosomal outer membrane protein 19 (Homp19) has no known homology. Furthermore, our data indicate that TvTOM is associated with sorting and assembly machinery (Sam)50 that is involved in β-barrel assembly. Visualisation of TvTOM by electron microscopy revealed that it forms three pores and has an unconventional skull-like shape. Although TvTOM seems to lack Tom7, our phylogenetic profiling predicted Tom7 in free-living excavates. Collectively, our results suggest that the triplet-pore TOM complex, composed of three conserved subunits, was present in the last common eukaryotic ancestor (LECA), while receptors responsible for substrate binding evolved independently in different eukaryotic lineages. The highly divergent outer membrane translocase (TOM) from the Trichomonas hydrogenosome (an organelle related to mitochondria) is composed of conserved core and lineage-specific subunits, and has an unconventional skull-like triplet-pore structure. Mitochondria carry out many vital functions in the eukaryotic cells, from energy metabolism to programmed cell death. These organelles descended from bacterial endosymbionts, and during their evolution, the cell established a mechanism to transport nuclear-encoded proteins into mitochondria. Embedded in the mitochondrial outer membrane is a molecular machine, known as the translocase of the outer membrane (TOM) complex, that plays a key role in protein import and biogenesis of the organelle. Here, we provide evidence that the TOM complex of hydrogenosomes, a metabolically specialised anaerobic form of mitochondria in Trichomonas vaginalis, is composed of highly divergent core subunits and lineage-specific peripheral subunits. Despite the evolutionary distance, the T. vaginalis TOM (TvTOM) complex has a conserved triplet-pore structure but with a unique skull-like shape suggesting that the TOM in the early mitochondrion could have formed three pores. Our results contribute to a better understanding of the evolution and adaptation of protein import machinery in anaerobic forms of mitochondria.
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Affiliation(s)
- Abhijith Makki
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Prague, Czech Republic
| | - Petr Rada
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Prague, Czech Republic
| | - Vojtěch Žárský
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Prague, Czech Republic
| | - Sami Kereïche
- Institute of Biology and Medical Genetics, First Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Lubomír Kováčik
- Institute of Biology and Medical Genetics, First Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Marian Novotný
- Department of Cell Biology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Tobias Jores
- Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, Germany
| | - Doron Rapaport
- Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, Germany
| | - Jan Tachezy
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Prague, Czech Republic
- * E-mail:
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Hu Y, Zou W, Wang Z, Zhang Y, Hu Y, Qian J, Wu X, Ren Y, Zhao J. Translocase of the Outer Mitochondrial Membrane 40 Is Required for Mitochondrial Biogenesis and Embryo Development in Arabidopsis. FRONTIERS IN PLANT SCIENCE 2019; 10:389. [PMID: 31001303 PMCID: PMC6455079 DOI: 10.3389/fpls.2019.00389] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Accepted: 03/13/2019] [Indexed: 05/08/2023]
Abstract
In eukaryotes, mitochondrion is an essential organelle which is surrounded by a double membrane system, including the outer membrane, intermembrane space and the inner membrane. The translocase of the outer mitochondrial membrane (TOM) complex has attracted enormous interest for its role in importing the preprotein from the cytoplasm into the mitochondrion. However, little is understood about the potential biological function of the TOM complex in Arabidopsis. The aim of the present study was to investigate how AtTOM40, a gene encoding the core subunit of the TOM complex, works in Arabidopsis. As a result, we found that lack of AtTOM40 disturbed embryo development and its pattern formation after the globular embryo stage, and finally caused albino ovules and seed abortion at the ratio of a quarter in the homozygous tom40 plants. Further investigation demonstrated that AtTOM40 is wildly expressed in different tissues, especially in cotyledons primordium during Arabidopsis embryogenesis. Moreover, we confirmed that the encoded protein AtTOM40 is localized in mitochondrion, and the observation of the ultrastructure revealed that mitochondrion biogenesis was impaired in tom40-1 embryo cells. Quantitative real-time PCR was utilized to determine the expression of genes encoding outer mitochondrial membrane proteins in the homozygous tom40-1 mutant embryos, including the genes known to be involved in import, assembly and transport of mitochondrial proteins, and the results demonstrated that most of the gene expressions were abnormal. Similarly, the expression of genes relevant to embryo development and pattern formation, such as SAM (shoot apical meristem), cotyledon, vascular primordium and hypophysis, was also affected in homozygous tom40-1 mutant embryos. Taken together, we draw the conclusion that the AtTOM40 gene is essential for the normal structure of the mitochondrion, and participates in early embryo development and pattern formation through maintaining the biogenesis of mitochondria. The findings of this study may provide new insight into the biological function of the TOM40 subunit in higher plants.
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Efflux pump-mediated resistance to antifungal compounds can be prevented by conjugation with triphenylphosphonium cation. Nat Commun 2018; 9:5102. [PMID: 30504815 PMCID: PMC6269435 DOI: 10.1038/s41467-018-07633-9] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Accepted: 11/13/2018] [Indexed: 11/21/2022] Open
Abstract
Antifungal resistance due to upregulation of efflux pumps is prevalent in clinical Candida isolates. Potential efflux pump substrates (PEPSs), which are active against strains deficient in efflux pumps but inactive against wild-type strains, are usually missed in routine antifungal screening. Here we present a method for identification of PEPSs, and show that conjugation with mitochondria-targeting triphenylphosphonium cation (TPP+) can enhance or restore the compounds’ antifungal activity. The screening method involves co-culturing a wild-type C. albicans strain and a Cdr efflux pump-deficient strain, labelled with different fluorescent proteins. We identify several PEPSs from a library of natural terpenes, and restore their antifungal activity against wild-type and azole-resistant C. albicans by conjugation with TPP+. The most active conjugate (IS-2-Pi-TPP) kills C. albicans cells, prevents biofilm formation and eliminates preformed biofilms, without inducing significant resistance. The antifungal activity is accompanied by mitochondrial dysfunction and increased levels of intracellular reactive oxygen species. In addition, IS-2-Pi-TPP is effective against C. albicans in a mouse model of skin infection. Antifungal resistance due to upregulation of efflux pumps is common in Candida albicans. Here, the authors show that conjugation with mitochondria-targeting triphenylphosphonium cation can enhance or restore the antifungal activity of potential efflux pump substrates.
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26
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Structural characterisation of a full-length mitochondrial outer membrane TOM40 preprotein translocase: implications for its interaction with presequence peptides. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2018; 48:35-43. [PMID: 30121780 DOI: 10.1007/s00249-018-1329-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2017] [Accepted: 08/12/2018] [Indexed: 10/28/2022]
Abstract
Tom40, the central component of the preprotein translocase of the mitochondrial outer membrane (TOM complex), forms the import pore that facilitates the translocation of preproteins across the outer membrane. Though the function of Tom40 has been intensively studied, the details of the interactions between presequence peptides and Tom40 remain unclear. In this study, we expressed rat Tom40 in Escherichia coli and purified it from inclusion bodies before investigating the refolded protein by fluorescence spectroscopy and circular dichroism (CD) spectroscopy. The far-UV CD spectra of the refolded Tom40 in various concentrations of urea revealed that the refolded protein has a well-defined structure consisting mainly of β-sheet. Moreover, the specific binding of presequence peptides to Tom40, which was demonstrated by fluorescence quenching, showed that the refolded purified protein is functional and that the interaction between Tom40 and presequence peptides is mainly electrostatic in nature.
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27
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Becker T, Wagner R. Mitochondrial Outer Membrane Channels: Emerging Diversity in Transport Processes. Bioessays 2018; 40:e1800013. [DOI: 10.1002/bies.201800013] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Revised: 03/29/2018] [Indexed: 01/06/2023]
Affiliation(s)
- Thomas Becker
- Faculty of MedicineInstitute of Biochemistry and Molecular Biology, ZBMZUniversity of FreiburgFreiburgD‐79104Germany
- BIOSS Centre for Biological Signalling StudiesUniversity of FreiburgFreiburgD‐79104Germany
| | - Richard Wagner
- Biophysics, Life Sciences & ChemistryJacobs University BremenBremenD‐28759Germany
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28
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TOM70 Sustains Cell Bioenergetics by Promoting IP3R3-Mediated ER to Mitochondria Ca 2+ Transfer. Curr Biol 2018; 28:369-382.e6. [PMID: 29395920 DOI: 10.1016/j.cub.2017.12.047] [Citation(s) in RCA: 102] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2017] [Revised: 11/22/2017] [Accepted: 12/20/2017] [Indexed: 01/09/2023]
Abstract
The mitochondrial translocase of the outer membrane (TOM) is a protein complex that is essential for the post-translational import of nuclear-encoded mitochondrial proteins. Among its subunits, TOM70 and TOM20 are only transiently associated with the core complex, suggesting their possible additional roles within the outer mitochondrial membrane (OMM). Here, by using different mammalian cell lines, we demonstrate that TOM70, but not TOM20, clusters in distinct OMM foci, frequently overlapping with sites in which the endoplasmic reticulum (ER) contacts mitochondria. Functionally, TOM70 depletion specifically impairs inositol trisphosphates (IP3)-linked ER to mitochondria Ca2+ transfer. This phenomenon is dependent on the capacity of TOM70 to interact with IP3-receptors and favor their functional recruitment close to mitochondria. Importantly, the reduced constitutive Ca2+ transfer to mitochondria, observed in TOM70-depleted cells, dampens mitochondrial respiration, affects cell bioenergetics, induces autophagy, and inhibits proliferation. Our data reveal a hitherto unexpected role for TOM70 in pro-survival ER-mitochondria communication, reinforcing the view that the ER-mitochondria signaling platform is a key regulator of cell fate.
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29
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Zheng S, Chang W, Zhang M, Shi H, Lou H. Chiloscyphenol A derived from Chinese liverworts exerts fungicidal action by eliciting both mitochondrial dysfunction and plasma membrane destruction. Sci Rep 2018; 8:326. [PMID: 29321629 PMCID: PMC5762906 DOI: 10.1038/s41598-017-18717-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Accepted: 12/14/2017] [Indexed: 12/13/2022] Open
Abstract
This study aimed to characterize the antifungal effects of chiloscyphenol A (CA), a natural small molecule isolated from Chinese liverworts, and investigate its mode of action. CA was effective against five tested Candida species with a minimal inhibitory concentration (MIC) of 8-32 μg/ml and exhibited fungicidal activity against Candida albicans in both the planktonic state and mature biofilms. The in vivo study using Caenorhabditis elegans showed that CA prolonged the survival of C. albicans infected worms. Further investigations revealed that CA resulted in mitochondrial dysfunction as indicated by mtΔψ hyperpolarization, increased ATP production and intracellular ROS accumulation, and aggregated distribution of Tom70. In addition, CA caused perturbation of the cell membrane and increased membrane permeability, as demonstrated by specific staining and confocal microscopic and transmission electron microscopy (TEM) observations and by calcein-leakage measurements. This conclusion was further confirmed by the decreased cell size of CA-treated cells via three-dimensional contour-plot analysis using flow cytometry. Taken together, these results suggest that CA exerts fungicidal activity by eliciting both mitochondrial dysfunction and plasma membrane destruction in C. albicans. The elucidated mechanism supports the potential application of CA against clinical fungal infections.
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Affiliation(s)
- Sha Zheng
- Department of Natural Product Chemistry, Key Lab of Chemical Biology of Ministry of Education, Shandong University, No. 44 West Wenhua Road, Jinan City, Shandong Province, China
| | - Wenqiang Chang
- Department of Natural Product Chemistry, Key Lab of Chemical Biology of Ministry of Education, Shandong University, No. 44 West Wenhua Road, Jinan City, Shandong Province, China
| | - Ming Zhang
- Department of Natural Product Chemistry, Key Lab of Chemical Biology of Ministry of Education, Shandong University, No. 44 West Wenhua Road, Jinan City, Shandong Province, China
| | - Hongzhuo Shi
- Department of Natural Product Chemistry, Key Lab of Chemical Biology of Ministry of Education, Shandong University, No. 44 West Wenhua Road, Jinan City, Shandong Province, China
| | - Hongxiang Lou
- Department of Natural Product Chemistry, Key Lab of Chemical Biology of Ministry of Education, Shandong University, No. 44 West Wenhua Road, Jinan City, Shandong Province, China.
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30
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Krüger V, Becker T, Becker L, Montilla-Martinez M, Ellenrieder L, Vögtle FN, Meyer HE, Ryan MT, Wiedemann N, Warscheid B, Pfanner N, Wagner R, Meisinger C. Identification of new channels by systematic analysis of the mitochondrial outer membrane. J Cell Biol 2017; 216:3485-3495. [PMID: 28916712 PMCID: PMC5674900 DOI: 10.1083/jcb.201706043] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Revised: 08/03/2017] [Accepted: 08/22/2017] [Indexed: 02/08/2023] Open
Abstract
Channels in the mitochondrial outer membrane exchange metabolites, ions, and proteins with the rest of the cell. Kruger et al. identify several new types of channel and suggest that the outer mitochondrial membrane is a more selective molecular sieve with a greater variety of channel-forming proteins than previously appreciated. The mitochondrial outer membrane is essential for communication between mitochondria and the rest of the cell and facilitates the transport of metabolites, ions, and proteins. All mitochondrial outer membrane channels known to date are β-barrel membrane proteins, including the abundant voltage-dependent anion channel and the cation-preferring protein-conducting channels Tom40, Sam50, and Mdm10. We analyzed outer membrane fractions of yeast mitochondria and identified four new channel activities: two anion-preferring channels and two cation-preferring channels. We characterized the cation-preferring channels at the molecular level. The mitochondrial import component Mim1 forms a channel that is predicted to have an α-helical structure for protein import. The short-chain dehydrogenase-related protein Ayr1 forms an NADPH-regulated channel. We conclude that the mitochondrial outer membrane contains a considerably larger variety of channel-forming proteins than assumed thus far. These findings challenge the traditional view of the outer membrane as an unspecific molecular sieve and indicate a higher degree of selectivity and regulation of metabolite fluxes at the mitochondrial boundary.
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Affiliation(s)
- Vivien Krüger
- Division of Biophysics, School of Biology/Chemistry, University of Osnabrück, Osnabrück, Germany.,Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Thomas Becker
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, Freiburg, Germany.,BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany
| | - Lars Becker
- Division of Biophysics, School of Biology/Chemistry, University of Osnabrück, Osnabrück, Germany
| | | | - Lars Ellenrieder
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - F-Nora Vögtle
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Helmut E Meyer
- Leibniz-Institut für Analytische Wissenschaften-ISAS-e.V., Dortmund, Germany
| | - Michael T Ryan
- Department of Biochemistry and Molecular Biology, Monash Biomedicine Discovery Institute, Monash University, Melbourne, Australia
| | - Nils Wiedemann
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, Freiburg, Germany.,BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany
| | - Bettina Warscheid
- BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany.,Institute of Biology II, Biochemistry - Functional Proteomics, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Nikolaus Pfanner
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, Freiburg, Germany .,BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany
| | - Richard Wagner
- Division of Biophysics, School of Biology/Chemistry, University of Osnabrück, Osnabrück, Germany .,Biophysics, Life Sciences and Chemistry, Jacobs University Bremen, Bremen, Germany
| | - Chris Meisinger
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, Freiburg, Germany.,BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany
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31
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Way L, Faktor J, Dvorakova P, Nicholson J, Vojtesek B, Graham D, Ball KL, Hupp T. Rearrangement of mitochondrial pyruvate dehydrogenase subunit dihydrolipoamide dehydrogenase protein-protein interactions by the MDM2 ligand nutlin-3. Proteomics 2017; 16:2327-44. [PMID: 27273042 PMCID: PMC5026170 DOI: 10.1002/pmic.201500501] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2015] [Revised: 04/27/2016] [Accepted: 06/03/2016] [Indexed: 12/22/2022]
Abstract
Drugs targeting MDM2's hydrophobic pocket activate p53. However, these agents act allosterically and have agonist effects on MDM2's protein interaction landscape. Dominant p53‐independent MDM2‐drug responsive‐binding proteins have not been stratified. We used as a variable the differential expression of MDM2 protein as a function of cell density to identify Nutlin‐3 responsive MDM2‐binding proteins that are perturbed independent of cell density using SWATH‐MS. Dihydrolipoamide dehydrogenase, the E3 subunit of the mitochondrial pyruvate dehydrogenase complex, was one of two Nutlin‐3 perturbed proteins identified fours hour posttreatment at two cell densities. Immunoblotting confirmed that dihydrolipoamide dehydrogenase was induced by Nutlin‐3. Depletion of MDM2 using siRNA also elevated dihydrolipoamide dehydrogenase in Nutlin‐3 treated cells. Mitotracker confirmed that Nutlin‐3 inhibits mitochondrial activity. Enrichment of mitochondria using TOM22+ immunobeads and TMT labeling defined key changes in the mitochondrial proteome after Nutlin‐3 treatment. Proximity ligation identified rearrangements of cellular protein–protein complexes in situ. In response to Nutlin‐3, a reduction of dihydrolipoamide dehydrogenase/dihydrolipoamide acetyltransferase protein complexes highlighted a disruption of the pyruvate dehydrogenase complex. This coincides with an increase in MDM2/dihydrolipoamide dehydrogenase complexes in the nucleus that was further enhanced by the nuclear export inhibitor Leptomycin B. The data suggest one therapeutic impact of MDM2 drugs might be on the early perturbation of specific protein–protein interactions within the mitochondria. This methodology forms a blueprint for biomarker discovery that can identify rearrangements of MDM2 protein–protein complexes in drug‐treated cells.
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Affiliation(s)
- Luke Way
- Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, Scotland, UK
| | - Jakub Faktor
- Regional Centre for Applied Molecular Oncology, Masaryk Memorial Cancer Institute, Brno, Czech Republic
| | - Petra Dvorakova
- Regional Centre for Applied Molecular Oncology, Masaryk Memorial Cancer Institute, Brno, Czech Republic
| | - Judith Nicholson
- CRUK & MRC Oxford Institute for Radiation Oncology, University of Oxford, Oxford, UK
| | - Borek Vojtesek
- Regional Centre for Applied Molecular Oncology, Masaryk Memorial Cancer Institute, Brno, Czech Republic
| | - Duncan Graham
- Centre for Molecular Nanometrology, WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde, Glasgow, UK
| | - Kathryn L Ball
- Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, Scotland, UK.,Regional Centre for Applied Molecular Oncology, Masaryk Memorial Cancer Institute, Brno, Czech Republic
| | - Ted Hupp
- Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, Scotland, UK. .,Regional Centre for Applied Molecular Oncology, Masaryk Memorial Cancer Institute, Brno, Czech Republic.
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32
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Bausewein T, Mills DJ, Langer JD, Nitschke B, Nussberger S, Kühlbrandt W. Cryo-EM Structure of the TOM Core Complex from Neurospora crassa. Cell 2017; 170:693-700.e7. [DOI: 10.1016/j.cell.2017.07.012] [Citation(s) in RCA: 92] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Revised: 06/22/2017] [Accepted: 07/11/2017] [Indexed: 01/21/2023]
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33
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Protein trafficking in the mitochondrial intermembrane space: mechanisms and links to human disease. Biochem J 2017; 474:2533-2545. [PMID: 28701417 PMCID: PMC5509380 DOI: 10.1042/bcj20160627] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Revised: 05/03/2017] [Accepted: 05/09/2017] [Indexed: 01/20/2023]
Abstract
Mitochondria fulfill a diverse range of functions in cells including oxygen metabolism, homeostasis of inorganic ions and execution of apoptosis. Biogenesis of mitochondria relies on protein import pathways that are ensured by dedicated multiprotein translocase complexes localized in all sub-compartments of these organelles. The key components and pathways involved in protein targeting and assembly have been characterized in great detail over the last three decades. This includes the oxidative folding machinery in the intermembrane space, which contributes to the redox-dependent control of proteostasis. Here, we focus on several components of this system and discuss recent evidence suggesting links to human proteopathy.
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34
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Ellenrieder L, Rampelt H, Becker T. Connection of Protein Transport and Organelle Contact Sites in Mitochondria. J Mol Biol 2017; 429:2148-2160. [DOI: 10.1016/j.jmb.2017.05.023] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Revised: 05/19/2017] [Accepted: 05/23/2017] [Indexed: 12/31/2022]
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35
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van Dooren GG, Yeoh LM, Striepen B, McFadden GI. The Import of Proteins into the Mitochondrion of Toxoplasma gondii. J Biol Chem 2016; 291:19335-50. [PMID: 27458014 DOI: 10.1074/jbc.m116.725069] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Indexed: 11/06/2022] Open
Abstract
Outside of well characterized model eukaryotes, relatively little is known about the translocons that transport proteins across the two membranes that surround the mitochondrion. Apicomplexans are a phylum of intracellular parasites that cause major diseases in humans and animals and are evolutionarily distant from model eukaryotes such as yeast. Apicomplexans harbor a mitochondrion that is essential for parasite survival and is a validated drug target. Here, we demonstrate that the apicomplexan Toxoplasma gondii harbors homologues of proteins from all the major mitochondrial protein translocons present in yeast, suggesting these arose early in eukaryotic evolution. We demonstrate that a T. gondii homologue of Tom22 (TgTom22), a central component of the translocon of the outer mitochondrial membrane (TOM) complex, is essential for parasite survival, mitochondrial protein import, and assembly of the TOM complex. We also identify and characterize a T. gondii homologue of Tom7 (TgTom7) that is important for parasite survival and mitochondrial protein import. Contrary to the role of Tom7 in yeast, TgTom7 is important for TOM complex stability, suggesting the role of this protein has diverged during eukaryotic evolution. Together, our study identifies conserved and modified features of mitochondrial protein import in apicomplexan parasites.
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Affiliation(s)
- Giel G van Dooren
- From the Research School of Biology, Australian National University, Canberra, Australian Capital Territory 2601, Australia,
| | - Lee M Yeoh
- the School of BioSciences, University of Melbourne, Parkville, Victoria 3010, Australia, and
| | - Boris Striepen
- the Department of Cellular Biology and Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia 30602
| | - Geoffrey I McFadden
- the School of BioSciences, University of Melbourne, Parkville, Victoria 3010, Australia, and
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36
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Revisiting trends on mitochondrial mega-channels for the import of proteins and nucleic acids. J Bioenerg Biomembr 2016; 49:75-99. [DOI: 10.1007/s10863-016-9662-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Accepted: 04/25/2016] [Indexed: 12/14/2022]
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37
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Shiota T, Imai K, Qiu J, Hewitt VL, Tan K, Shen HH, Sakiyama N, Fukasawa Y, Hayat S, Kamiya M, Elofsson A, Tomii K, Horton P, Wiedemann N, Pfanner N, Lithgow T, Endo T. Molecular architecture of the active mitochondrial protein gate. Science 2015; 349:1544-8. [DOI: 10.1126/science.aac6428] [Citation(s) in RCA: 144] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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38
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Kuszak AJ, Jacobs D, Gurnev PA, Shiota T, Louis JM, Lithgow T, Bezrukov SM, Rostovtseva TK, Buchanan SK. Evidence of Distinct Channel Conformations and Substrate Binding Affinities for the Mitochondrial Outer Membrane Protein Translocase Pore Tom40. J Biol Chem 2015; 290:26204-17. [PMID: 26336107 DOI: 10.1074/jbc.m115.642173] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Indexed: 12/14/2022] Open
Abstract
Nearly all mitochondrial proteins are coded by the nuclear genome and must be transported into mitochondria by the translocase of the outer membrane complex. Tom40 is the central subunit of the translocase complex and forms a pore in the mitochondrial outer membrane. To date, the mechanism it utilizes for protein transport remains unclear. Tom40 is predicted to comprise a membrane-spanning β-barrel domain with conserved α-helical domains at both the N and C termini. To investigate Tom40 function, including the role of the N- and C-terminal domains, recombinant forms of the Tom40 protein from the yeast Candida glabrata, and truncated constructs lacking the N- and/or C-terminal domains, were functionally characterized in planar lipid membranes. Our results demonstrate that each of these Tom40 constructs exhibits at least four distinct conductive levels and that full-length and truncated Tom40 constructs specifically interact with a presequence peptide in a concentration- and voltage-dependent manner. Therefore, neither the first 51 amino acids of the N terminus nor the last 13 amino acids of the C terminus are required for Tom40 channel formation or for the interaction with a presequence peptide. Unexpectedly, substrate binding affinity was dependent upon the Tom40 state corresponding to a particular conductive level. A model where two Tom40 pores act in concert as a dimeric protein complex best accounts for the observed biochemical and electrophysiological data. These results provide the first evidence for structurally distinct Tom40 conformations playing a role in substrate recognition and therefore in transport function.
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Affiliation(s)
| | - Daniel Jacobs
- From the Laboratories of Molecular Biology and Program in Physical Biology, NICHD, National Institutes of Health, Bethesda, Maryland 20892
| | - Philip A Gurnev
- Program in Physical Biology, NICHD, National Institutes of Health, Bethesda, Maryland 20892, the Physics Department, University of Massachusetts, Amherst, Massachusetts 01003, and
| | - Takuya Shiota
- the Department of Microbiology, Monash University, Melbourne 3800, Victoria, Australia
| | | | - Trevor Lithgow
- the Department of Microbiology, Monash University, Melbourne 3800, Victoria, Australia
| | - Sergey M Bezrukov
- Program in Physical Biology, NICHD, National Institutes of Health, Bethesda, Maryland 20892
| | - Tatiana K Rostovtseva
- Program in Physical Biology, NICHD, National Institutes of Health, Bethesda, Maryland 20892,
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39
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Li Y, Chang W, Zhang M, Li X, Jiao Y, Lou H. Diorcinol D Exerts Fungicidal Action against Candida albicans through Cytoplasm Membrane Destruction and ROS Accumulation. PLoS One 2015; 10:e0128693. [PMID: 26047493 PMCID: PMC4457822 DOI: 10.1371/journal.pone.0128693] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Accepted: 04/29/2015] [Indexed: 02/01/2023] Open
Abstract
Candida albicans, which is the most common human fungal pathogen, causes high mortality among immunocompromised patients. Antifungal drug resistance becomes a major challenge for the management of Candida infection. Diorcinol D (DD), a diphenyl ether derivative isolated from an endolichenic fungus, exerted fungicidal action against Candida species. In this study, we investigated the possible mechanism of its antifungal activity. The change of membrane dynamics and permeability suggested that the cell membrane was disrupted by the treatment of DD. This was further supported by the evidences of intracellular glycerol accumulation, alteration of cell ultrastructure, and down-regulation of genes involved in cell membrane synthesis. In addition, the treatment of C. albicans with DD resulted in the elevation of reactive oxygen species (ROS), which caused the dysfunction of mitochondria. These altogether suggested that DD exerted its antifungal activity through cytoplasmic membrane destruction and ROS accumulation. This finding is helpful to uncover the underlying mechanisms for the diphenyl ether derivatives and provides a potential application in fighting clinical fungal infections.
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Affiliation(s)
- Ying Li
- Department of Natural Product Chemistry, Key Lab of Chemical Biology of Ministry of Education, Shandong University, No. 44 West Wenhua Road, Jinan City, Shandong Province, China
| | - Wenqiang Chang
- Department of Natural Product Chemistry, Key Lab of Chemical Biology of Ministry of Education, Shandong University, No. 44 West Wenhua Road, Jinan City, Shandong Province, China
| | - Ming Zhang
- Department of Natural Product Chemistry, Key Lab of Chemical Biology of Ministry of Education, Shandong University, No. 44 West Wenhua Road, Jinan City, Shandong Province, China
| | - Xiaobin Li
- Department of Natural Product Chemistry, Key Lab of Chemical Biology of Ministry of Education, Shandong University, No. 44 West Wenhua Road, Jinan City, Shandong Province, China
| | - Yang Jiao
- Department of Natural Product Chemistry, Key Lab of Chemical Biology of Ministry of Education, Shandong University, No. 44 West Wenhua Road, Jinan City, Shandong Province, China
| | - Hongxiang Lou
- Department of Natural Product Chemistry, Key Lab of Chemical Biology of Ministry of Education, Shandong University, No. 44 West Wenhua Road, Jinan City, Shandong Province, China
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40
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Wojtkowska M, Buczek D, Stobienia O, Karachitos A, Antoniewicz M, Slocinska M, Makałowski W, Kmita H. The TOM Complex of Amoebozoans: the Cases of the Amoeba Acanthamoeba castellanii and the Slime Mold Dictyostelium discoideum. Protist 2015; 166:349-62. [PMID: 26074248 DOI: 10.1016/j.protis.2015.05.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2014] [Revised: 05/10/2015] [Accepted: 05/14/2015] [Indexed: 11/29/2022]
Abstract
Protein import into mitochondria requires a wide variety of proteins, forming complexes in both mitochondrial membranes. The TOM complex (translocase of the outer membrane) is responsible for decoding of targeting signals, translocation of imported proteins across or into the outer membrane, and their subsequent sorting. Thus the TOM complex is regarded as the main gate into mitochondria for imported proteins. Available data indicate that mitochondria of representative organisms from across the major phylogenetic lineages of eukaryotes differ in subunit organization of the TOM complex. The subunit organization of the TOM complex in the Amoebozoa is still elusive, so we decided to investigate its organization in the soil amoeba Acanthamoeba castellanii and the slime mold Dictyostelium discoideum. They represent two major subclades of the Amoebozoa: the Lobosa and Conosa, respectively. Our results confirm the presence of Tom70, Tom40 and Tom7 in the A. castellanii and D. discoideum TOM complex, while the presence of Tom22 and Tom20 is less supported. Interestingly, the Tom proteins display the highest similarity to Opisthokonta cognate proteins, with the exception of Tom40. Thus representatives of two major subclades of the Amoebozoa appear to be similar in organization of the TOM complex, despite differences in their lifestyle.
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Affiliation(s)
- Małgorzata Wojtkowska
- Adam Mickiewicz University, Faculty of Biology, Institute of Molecular Biology and Biotechnology, Department of Bioenergetics, Poznań, Poland.
| | - Dorota Buczek
- Adam Mickiewicz University, Faculty of Biology, Institute of Molecular Biology and Biotechnology, Department of Bioenergetics, Poznań, Poland; University of Muenster, Faculty of Medicine Institute of Bioinformatics, Muenster, Germany
| | - Olgierd Stobienia
- Adam Mickiewicz University, Faculty of Biology, Institute of Molecular Biology and Biotechnology, Department of Bioenergetics, Poznań, Poland
| | - Andonis Karachitos
- Adam Mickiewicz University, Faculty of Biology, Institute of Molecular Biology and Biotechnology, Department of Bioenergetics, Poznań, Poland
| | - Monika Antoniewicz
- Adam Mickiewicz University, Faculty of Biology, Institute of Molecular Biology and Biotechnology, Department of Bioenergetics, Poznań, Poland
| | - Małgorzata Slocinska
- Adam Mickiewicz University, Faculty of Biology, Institute of Experimental Biology, Department of Animal Physiology and Development, Poznań, Poland
| | - Wojciech Makałowski
- University of Muenster, Faculty of Medicine Institute of Bioinformatics, Muenster, Germany
| | - Hanna Kmita
- Adam Mickiewicz University, Faculty of Biology, Institute of Molecular Biology and Biotechnology, Department of Bioenergetics, Poznań, Poland
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41
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Cooperation of protein machineries in mitochondrial protein sorting. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1853:1119-29. [DOI: 10.1016/j.bbamcr.2015.01.012] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Revised: 01/16/2015] [Accepted: 01/20/2015] [Indexed: 02/07/2023]
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42
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A Perspective on Transport of Proteins into Mitochondria: A Myriad of Open Questions. J Mol Biol 2015; 427:1135-58. [DOI: 10.1016/j.jmb.2015.02.001] [Citation(s) in RCA: 91] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Revised: 01/30/2015] [Accepted: 02/02/2015] [Indexed: 11/22/2022]
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43
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Sun L, Hartson SD, Matts RL. Identification of proteins associated with Aha1 in HeLa cells by quantitative proteomics. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2015; 1854:365-80. [PMID: 25614414 DOI: 10.1016/j.bbapap.2015.01.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Revised: 12/20/2014] [Accepted: 01/09/2015] [Indexed: 01/17/2023]
Abstract
The identification of the activator of heat shock protein 90 (Hsp90) ATPase's (Aha1) protein-protein interaction (PPI) network will provide critical insights into the relationship of Aha1 with multi-molecular complexes and shed light onto Aha1's interconnections with Hsp90-regulated biological functions. Flag-tagged Aha1 was over-expressed in HeLa cells and isolated by anti-Flag affinity pull downs, followed by trypsin digestion and identification co-adsorbing proteins by liquid chromatography-tandem mass spectroscopy (LC-MS/MS). A probability-based identification of Aha1 PPIs was generated from the LC-MS/MS analysis by using a relative quantification strategy, spectral counting (SC). By comparing the SC-based protein levels between Aha1 pull-down samples and negative controls, 164 Aha1-interacting proteins were identified that were quantitatively enriched in the pull-down samples over the controls. The identified Aha1-interacting proteins are involved in a wide number of intracellular bioprocesses, including DNA maintenance, chromatin structure, RNA processing, translation, nucleocytoplasmic and vesicle transport, among others. The interactions of 33 of the identified proteins with Aha1 were further confirmed by Western blotting, demonstrating the reliability of our affinity-purification-coupled quantitative SC-MS strategy. Our proteomic data suggests that Aha1 may participate in diverse biological pathways to facilitate Hsp90 chaperone functions in response to stress.
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Affiliation(s)
- Liang Sun
- Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, OK 74078, USA
| | - Steven D Hartson
- Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, OK 74078, USA
| | - Robert L Matts
- Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, OK 74078, USA.
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44
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Presequence recognition by the tom40 channel contributes to precursor translocation into the mitochondrial matrix. Mol Cell Biol 2014; 34:3473-85. [PMID: 25002531 DOI: 10.1128/mcb.00433-14] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
More than 70% of mitochondrial proteins utilize N-terminal presequences as targeting signals. Presequence interactions with redundant cytosolic receptor domains of the translocase of the outer mitochondrial membrane (TOM) are well established. However, after the presequence enters the protein-conducting Tom40 channel, the recognition events that occur at the trans side leading up to the engagement of the presequence with inner membrane-bound receptors are less well defined. Using a photoaffinity-labeling approach with modified presequence peptides, we identified Tom40 as a presequence interactor of the TOM complex. Utilizing mass spectrometry, we mapped Tom40's presequence-interacting regions to both sides of the β-barrel. Analysis of a phosphorylation site within one of the presequence-interacting regions revealed altered translocation kinetics along the presequence pathway. Our analyses assess the relation between the identified presequence-binding region of Tom40 and the intermembrane space domain of Tom22. The identified presequence-interacting region of Tom40 is capable of functioning independently of the established trans-acting TOM presequence-binding domain during matrix import.
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45
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Lackey SWK, Taylor RD, Go NE, Wong A, Sherman EL, Nargang FE. Evidence supporting the 19 β-strand model for Tom40 from cysteine scanning and protease site accessibility studies. J Biol Chem 2014; 289:21640-50. [PMID: 24947507 DOI: 10.1074/jbc.m114.578765] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Most proteins found in mitochondria are translated in the cytosol and enter the organelle via the TOM complex (translocase of the outer mitochondrial membrane). Tom40 is the pore forming component of the complex. Although the three-dimensional structure of Tom40 has not been determined, the structure of porin, a related protein, has been shown to be a β-barrel containing 19 membrane spanning β-strands and an N-terminal α-helical region. The evolutionary relationship between the two proteins has allowed modeling of Tom40 into a similar structure by several laboratories. However, it has been suggested that the 19-strand porin structure does not represent the native form of the protein. If true, modeling of Tom40 based on the porin structure would also be invalid. We have used substituted cysteine accessibility mapping to identify several potential β-strands in the Tom40 protein in isolated mitochondria. These data, together with protease accessibility studies, support the 19 β-strand model for Tom40 with the C-terminal end of the protein localized to the intermembrane space.
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Affiliation(s)
- Sebastian W K Lackey
- From the Department of Biological Sciences, University of Alberta, Edmonton, Alberta T6G 2E9, Canada
| | - Rebecca D Taylor
- From the Department of Biological Sciences, University of Alberta, Edmonton, Alberta T6G 2E9, Canada
| | - Nancy E Go
- From the Department of Biological Sciences, University of Alberta, Edmonton, Alberta T6G 2E9, Canada
| | - Annie Wong
- From the Department of Biological Sciences, University of Alberta, Edmonton, Alberta T6G 2E9, Canada
| | - E Laura Sherman
- From the Department of Biological Sciences, University of Alberta, Edmonton, Alberta T6G 2E9, Canada
| | - Frank E Nargang
- From the Department of Biological Sciences, University of Alberta, Edmonton, Alberta T6G 2E9, Canada
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46
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Abstract
The field of mitochondrial ion channels has recently seen substantial progress, including the molecular identification of some of the channels. An integrative approach using genetics, electrophysiology, pharmacology, and cell biology to clarify the roles of these channels has thus become possible. It is by now clear that many of these channels are important for energy supply by the mitochondria and have a major impact on the fate of the entire cell as well. The purpose of this review is to provide an up-to-date overview of the electrophysiological properties, molecular identity, and pathophysiological functions of the mitochondrial ion channels studied so far and to highlight possible therapeutic perspectives based on current information.
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47
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Idiosyncrasies in decoding mitochondrial genomes. Biochimie 2014; 100:95-106. [PMID: 24440477 DOI: 10.1016/j.biochi.2014.01.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2013] [Accepted: 01/06/2014] [Indexed: 11/24/2022]
Abstract
Mitochondria originate from the α-proteobacterial domain of life. Since this unique event occurred, mitochondrial genomes of protozoans, fungi, plants and metazoans have highly derived and diverged away from the common ancestral DNA. These resulting genomes highly differ from one another, but all present-day mitochondrial DNAs have a very reduced coding capacity. Strikingly however, ATP production coupled to electron transport and translation of mitochondrial proteins are the two common functions retained in all mitochondrial DNAs. Paradoxically, most components essential for these two functions are now expressed from nuclear genes. Understanding how mitochondrial translation evolved in various eukaryotic models is essential to acquire new knowledge of mitochondrial genome expression. In this review, we provide a thorough analysis of the idiosyncrasies of mitochondrial translation as they occur between organisms. We address this by looking at mitochondrial codon usage and tRNA content. Then, we look at the aminoacyl-tRNA-forming enzymes in terms of peculiarities, dual origin, and alternate function(s). Finally we give examples of the atypical structural properties of mitochondrial tRNAs found in some organisms and the resulting adaptive tRNA-protein partnership.
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48
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Kučera T, Otyepka M, Matušková A, Samad A, Kutejová E, Janata J. A computational study of the glycine-rich loop of mitochondrial processing peptidase. PLoS One 2013; 8:e74518. [PMID: 24058582 PMCID: PMC3772902 DOI: 10.1371/journal.pone.0074518] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2013] [Accepted: 08/02/2013] [Indexed: 11/21/2022] Open
Abstract
An all atomic, non-restrained molecular dynamics (MD) simulation in explicit water was used to study in detail the structural features of the highly conserved glycine-rich loop (GRL) of the α-subunit of the yeast mitochondrial processing peptidase (MPP) and its importance for the tertiary and quaternary conformation of MPP. Wild-type and GRL-deleted MPP structures were studied using non-restrained MD simulations, both in the presence and the absence of a substrate in the peptidase active site. Targeted MD simulations were employed to study the mechanism of substrate translocation from the GRL to the active site. We demonstrate that the natural conformational flexibility of the GRL is crucial for the substrate translocation process from outside the enzyme towards the MPP active site. We show that the α-helical conformation of the substrate is important not only during its initial interaction with MPP (i.e. substrate recognition), but also later, at least during the first third of the substrate translocation trajectory. Further, we show that the substrate remains in contact with the GRL during the whole first half of the translocation trajectory and that hydrophobic interactions play a major role. Finally, we conclude that the GRL acts as a precisely balanced structural element, holding the MPP subunits in a partially closed conformation regardless the presence or absence of a substrate in the active site.
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Affiliation(s)
- Tomáš Kučera
- Institute of Microbiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic
- Department of Biochemistry, Faculty of Science, Charles University, Prague, Czech Republic
| | - Michal Otyepka
- Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science, Palacký University, Olomouc, Czech Republic
| | - Anna Matušková
- Institute of Microbiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Abdul Samad
- Institute of Microbiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Eva Kutejová
- Institute of Microbiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic
- Institute of Molecular Biology, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Jiří Janata
- Institute of Microbiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic
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49
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Bertolin G, Ferrando-Miguel R, Jacoupy M, Traver S, Grenier K, Greene AW, Dauphin A, Waharte F, Bayot A, Salamero J, Lombès A, Bulteau AL, Fon EA, Brice A, Corti O. The TOMM machinery is a molecular switch in PINK1 and PARK2/PARKIN-dependent mitochondrial clearance. Autophagy 2013; 9:1801-17. [PMID: 24149440 DOI: 10.4161/auto.25884] [Citation(s) in RCA: 100] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Loss-of-function mutations in PARK2/PARKIN and PINK1 cause early-onset autosomal recessive Parkinson disease (PD). The cytosolic E3 ubiquitin-protein ligase PARK2 cooperates with the mitochondrial kinase PINK1 to maintain mitochondrial quality. A loss of mitochondrial transmembrane potential (ΔΨ) leads to the PINK1-dependent recruitment of PARK2 to the outer mitochondrial membrane (OMM), followed by the ubiquitination and proteasome-dependent degradation of OMM proteins, and by the autophagy-dependent clearance of mitochondrial remnants. We showed here that blockade of mitochondrial protein import triggers the recruitment of PARK2, by PINK1, to the TOMM machinery. PD-causing PARK2 mutations weakened or disrupted the molecular interaction between PARK2 and specific TOMM subunits: the surface receptor, TOMM70A, and the channel protein, TOMM40. The downregulation of TOMM40 or its associated core subunit, TOMM22, was sufficient to trigger OMM protein clearance in the absence of PINK1 or PARK2. However, PARK2 was required to promote the degradation of whole organelles by autophagy. Furthermore, the overproduction of TOMM22 or TOMM40 reversed mitochondrial clearance promoted by PINK1 and PARK2 after ΔΨ loss. These results indicated that the TOMM machinery is a key molecular switch in the mitochondrial clearance program controlled by the PINK1-PARK2 pathway. Loss of functional coupling between mitochondrial protein import and the neuroprotective degradation of dysfunctional mitochondria may therefore be a primary pathogenic mechanism in autosomal recessive PD.
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Affiliation(s)
- Giulia Bertolin
- Inserm; U 975; CRICM; Hôpital de la Pitié-Salpêtrière; Paris, France; UPMC; Université Paris 06; UMR_S975; Paris, France; CNRS; UMR 7225; Paris, France
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50
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Mahendran KR, Lamichhane U, Romero-Ruiz M, Nussberger S, Winterhalter M. Polypeptide Translocation Through the Mitochondrial TOM Channel: Temperature-Dependent Rates at the Single-Molecule Level. J Phys Chem Lett 2013; 4:78-82. [PMID: 26291215 DOI: 10.1021/jz301790h] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The TOM protein complex facilitates the transfer of nearly all mitochondrial preproteins across outer mitochondrial membranes. Here we characterized the effect of temperature on facilitated translocation of a mitochondrial presequence peptide pF1β. Ion current fluctuations analysis through single TOM channels revealed thermodynamic and kinetic parameters of substrate binding and allowed determining the energy profile of peptide translocation. The activation energy for the on-rate and off-rate of the presequence peptide into the TOM complex was symmetric with respect to the electric field and estimated to be about 15 and 22 kT per peptide. These values are above that expected for free diffusion of ions in water (6 kT) and reflect the stronger interaction in the channel. Both values are in the range for typical enzyme kinetics and suggest one process without involving large conformational changes within the channel protein.
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Affiliation(s)
- Kozhinjampara R Mahendran
- †School of Engineering and Science, Jacobs University Bremen, Campus Ring 1, D-28759 Bremen, Germany
| | - Usha Lamichhane
- †School of Engineering and Science, Jacobs University Bremen, Campus Ring 1, D-28759 Bremen, Germany
| | - Mercedes Romero-Ruiz
- ‡Biophysics Department, Institute of Biology, University of Stuttgart, D-70550 Stuttgart, Germany
| | - Stephan Nussberger
- ‡Biophysics Department, Institute of Biology, University of Stuttgart, D-70550 Stuttgart, Germany
| | - Mathias Winterhalter
- †School of Engineering and Science, Jacobs University Bremen, Campus Ring 1, D-28759 Bremen, Germany
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