51
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Ueda E, Tamura Y, Sakaue H, Kawano S, Kakuta C, Matsumoto S, Endo T. Myristoyl group-aided protein import into the mitochondrial intermembrane space. Sci Rep 2019; 9:1185. [PMID: 30718713 PMCID: PMC6362269 DOI: 10.1038/s41598-018-38016-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Accepted: 12/12/2018] [Indexed: 12/20/2022] Open
Abstract
The MICOS complex mediates formation of the crista junctions in mitochondria. Here we analyzed the mitochondrial import pathways for the six yeast MICOS subunits as a step toward understanding of the assembly mechanisms of the MICOS complex. Mic10, Mic12, Mic26, Mic27, and Mic60 used the presequence pathway to reach the intermembrane space (IMS). In contrast, Mic19 took the TIM40/MIA pathway, through its CHCH domain, to reach the IMS. Unlike canonical TIM40/MIA substrates, presence of the N-terminal unfolded DUF domain impaired the import efficiency of Mic19, yet N-terminal myristoylation of Mic19 circumvented this effect. The myristoyl group of Mic19 binds to Tom20 of the TOM complex as well as the outer membrane, which may lead to "entropy pushing" of the DUF domain followed by the CHCH domain of Mic19 into the import channel, thereby achieving efficient import.
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Affiliation(s)
- Eri Ueda
- Department of Chemistry, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya, 464-8602, Japan
- Department of Biological Science, Graduate School of Science, Osaka University, 1-1 machikaneyama-cho, Toyonaka, 560-0043, Osaka, Japan
| | - Yasushi Tamura
- Department of Material and Biological Chemistry, Faculty of Science, Yamagata University, 1-4-12 Kojirakawa-machi, Yamagata, 990-8560, Japan
| | - Haruka Sakaue
- Faculty of Life Sciences, Kyoto Sangyo University, Kamigamo-motoyama, Kita-ku, Kyoto, 603-8555, Japan
- Research Center for Protein Dynamics, Kyoto Sangyo University, Kamigamo-motoyama, Kita-ku, Kyoto, 603-8555, Japan
| | - Shin Kawano
- Faculty of Life Sciences, Kyoto Sangyo University, Kamigamo-motoyama, Kita-ku, Kyoto, 603-8555, Japan
- Research Center for Protein Dynamics, Kyoto Sangyo University, Kamigamo-motoyama, Kita-ku, Kyoto, 603-8555, Japan
| | - Chika Kakuta
- Faculty of Life Sciences, Kyoto Sangyo University, Kamigamo-motoyama, Kita-ku, Kyoto, 603-8555, Japan
| | - Shunsuke Matsumoto
- Faculty of Life Sciences, Kyoto Sangyo University, Kamigamo-motoyama, Kita-ku, Kyoto, 603-8555, Japan
- Research Center for Protein Dynamics, Kyoto Sangyo University, Kamigamo-motoyama, Kita-ku, Kyoto, 603-8555, Japan
| | - Toshiya Endo
- Faculty of Life Sciences, Kyoto Sangyo University, Kamigamo-motoyama, Kita-ku, Kyoto, 603-8555, Japan.
- Research Center for Protein Dynamics, Kyoto Sangyo University, Kamigamo-motoyama, Kita-ku, Kyoto, 603-8555, Japan.
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52
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Klinger A, Gosch V, Bodensohn U, Ladig R, Schleiff E. The signal distinguishing between targeting of outer membrane β-barrel protein to plastids and mitochondria in plants. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2019; 1866:663-672. [PMID: 30633951 DOI: 10.1016/j.bbamcr.2019.01.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Revised: 12/03/2018] [Accepted: 01/07/2019] [Indexed: 12/15/2022]
Abstract
The proteome of the outer membrane of mitochondria and chloroplasts consists of membrane proteins anchored by α-helical or β-sheet elements. While proteins with α-helical transmembrane domains are present in all cellular membranes, proteins with β-barrel structure are specific for these two membranes. The organellar β-barrel proteins are encoded in the nuclear genome and thus, have to be targeted to the outer organellar membrane where they are recognized by surface exposed translocation complexes. In the last years, the signals that ensure proper targeting of these proteins have been investigated as essential base for an understanding of the regulation of cellular protein distribution. However, the organellar β-barrel proteins are unique as most of them do not contain a typical targeting information in form of an N-terminal cleavable targeting signal. Recently, it was discovered that targeting and surface recognition of mitochondrial β-barrel proteins in yeast, humans and plants depends on the hydrophobicity of the last β-hairpin of the β-barrel. However, we demonstrate that the hydrophobicity is not sufficient for the discrimination of targeting to chloroplasts or mitochondria. By domain swapping between mitochondrial and chloroplast targeted β-barrel proteins atVDAC1 and psOEP24 we demonstrate that the presence of a hydrophilic amino acid at the C-terminus of the penultimate β-strand is required for mitochondrial targeting. A mutation of the chloroplast β-barrel protein psOEP24 which mimics such profile is efficiently targeted to mitochondria. Thus, we present the properties of the signal for mitochondrial targeting of β-barrel proteins in plants.
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Affiliation(s)
- Anna Klinger
- Institute for Molecular Biosciences, Goethe University Frankfurt am Main, Max-von-Laue Str. 9, D-60438 Frankfurt, Germany
| | - Victoria Gosch
- Institute for Molecular Biosciences, Goethe University Frankfurt am Main, Max-von-Laue Str. 9, D-60438 Frankfurt, Germany
| | - Uwe Bodensohn
- Institute for Molecular Biosciences, Goethe University Frankfurt am Main, Max-von-Laue Str. 9, D-60438 Frankfurt, Germany
| | - Roman Ladig
- Institute for Molecular Biosciences, Goethe University Frankfurt am Main, Max-von-Laue Str. 9, D-60438 Frankfurt, Germany
| | - Enrico Schleiff
- Institute for Molecular Biosciences, Goethe University Frankfurt am Main, Max-von-Laue Str. 9, D-60438 Frankfurt, Germany; Buchman Institute for Molecular Life Sciences, Goethe University Frankfurt am Main, Max-von-Laue Str. 15, D-60438 Frankfurt, Germany; Frankfurt Institute of Advanced Studies, Ruth-Moufang-Straße 1, D-60438 Frankfurt, Germany.
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53
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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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54
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Weinhäupl K, Lindau C, Hessel A, Wang Y, Schütze C, Jores T, Melchionda L, Schönfisch B, Kalbacher H, Bersch B, Rapaport D, Brennich M, Lindorff-Larsen K, Wiedemann N, Schanda P. Structural Basis of Membrane Protein Chaperoning through the Mitochondrial Intermembrane Space. Cell 2018; 175:1365-1379.e25. [PMID: 30445040 PMCID: PMC6242696 DOI: 10.1016/j.cell.2018.10.039] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Revised: 08/16/2018] [Accepted: 10/15/2018] [Indexed: 12/04/2022]
Abstract
The exchange of metabolites between the mitochondrial matrix and the cytosol depends on β-barrel channels in the outer membrane and α-helical carrier proteins in the inner membrane. The essential translocase of the inner membrane (TIM) chaperones escort these proteins through the intermembrane space, but the structural and mechanistic details remain elusive. We have used an integrated structural biology approach to reveal the functional principle of TIM chaperones. Multiple clamp-like binding sites hold the mitochondrial membrane proteins in a translocation-competent elongated form, thus mimicking characteristics of co-translational membrane insertion. The bound preprotein undergoes conformational dynamics within the chaperone binding clefts, pointing to a multitude of dynamic local binding events. Mutations in these binding sites cause cell death or growth defects associated with impairment of carrier and β-barrel protein biogenesis. Our work reveals how a single mitochondrial "transfer-chaperone" system is able to guide α-helical and β-barrel membrane proteins in a "nascent chain-like" conformation through a ribosome-free compartment.
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Affiliation(s)
- Katharina Weinhäupl
- Institut de Biologie Structurale (IBS), Univ. Grenoble Alpes, CEA, CNRS, 71 Avenue des Martyrs, 38000 Grenoble, France
| | - Caroline Lindau
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany; Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany
| | - Audrey Hessel
- Institut de Biologie Structurale (IBS), Univ. Grenoble Alpes, CEA, CNRS, 71 Avenue des Martyrs, 38000 Grenoble, France
| | - Yong Wang
- Structural Biology and NMR Laboratory, the Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Conny Schütze
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany
| | - Tobias Jores
- Interfaculty Institute of Biochemistry, University of Tübingen, 72076 Tübingen, Germany
| | - Laura Melchionda
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany
| | - Birgit Schönfisch
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany
| | - Hubert Kalbacher
- Interfaculty Institute of Biochemistry, University of Tübingen, 72076 Tübingen, Germany
| | - Beate Bersch
- Institut de Biologie Structurale (IBS), Univ. Grenoble Alpes, CEA, CNRS, 71 Avenue des Martyrs, 38000 Grenoble, France
| | - Doron Rapaport
- Interfaculty Institute of Biochemistry, University of Tübingen, 72076 Tübingen, Germany
| | - Martha Brennich
- European Molecular Biology Laboratory, 38042 Grenoble, France
| | - Kresten Lindorff-Larsen
- Structural Biology and NMR Laboratory, the Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Nils Wiedemann
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany; BIOSS Centre for Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany.
| | - Paul Schanda
- Institut de Biologie Structurale (IBS), Univ. Grenoble Alpes, CEA, CNRS, 71 Avenue des Martyrs, 38000 Grenoble, France.
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55
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Puiggalí-Jou A, Pawlowski J, del Valle LJ, Michaux C, Perpète EA, Sek S, Alemán C. Properties of Omp2a-Based Supported Lipid Bilayers: Comparison with Polymeric Bioinspired Membranes. ACS OMEGA 2018; 3:9003-9019. [PMID: 31459033 PMCID: PMC6645002 DOI: 10.1021/acsomega.8b00913] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2018] [Accepted: 07/19/2018] [Indexed: 05/31/2023]
Abstract
Omp2a β-barrel outer membrane protein has been reconstituted into supported lipid bilayers (SLBs) to compare the nanomechanical properties (elastic modulus, adhesion forces, and deformation) and functionality of the resulting bioinspired system with those of Omp2a-based polymeric nanomembranes (NMs). Protein reconstitution into lipid bilayers has been performed using different strategies, the most successful one consisting of a detergent-mediated process into preformed liposomes. The elastic modulus obtained for the lipid bilayer and Omp2a are ∼19 and 10.5 ± 1.7 MPa, respectively. Accordingly, the protein is softer than the lipid bilayer, whereas the latter exhibits less mechanical strength than polymeric NMs. Besides, the function of Omp2a in the SLB is similar to that observed for Omp2a-based polymeric NMs. Results open the door to hybrid bioinspired substrates based on the integration of Omp2a-proteoliposomes and nanoperforated polymeric freestanding NMs.
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Affiliation(s)
- Anna Puiggalí-Jou
- Departament
d’Enginyeria Química, EEBE, Universitat Politècnica de Catalunya, C/Eduard Maristany, 10-14, Ed. I2, 08019 Barcelona, Spain
- Barcelona
Research Center for Multiscale Science and Engineering, Universitat Politècnica de Catalunya, C/Eduard Maristany, 10-14, Ed. C, 08019 Barcelona, Spain
| | - Jan Pawlowski
- Biological
and Chemical Research Centre, Faculty of Chemistry, University of Warsaw, Zwirki i Wigury 101, 02-089 Warsaw, Poland
| | - Luis J. del Valle
- Departament
d’Enginyeria Química, EEBE, Universitat Politècnica de Catalunya, C/Eduard Maristany, 10-14, Ed. I2, 08019 Barcelona, Spain
- Barcelona
Research Center for Multiscale Science and Engineering, Universitat Politècnica de Catalunya, C/Eduard Maristany, 10-14, Ed. C, 08019 Barcelona, Spain
| | - Catherine Michaux
- Laboratoire
de Chimie Physique des Biomolécules, University of Namur, Rue de Bruxelles, 61, 5000 Namur, Belgium
| | - Eric A. Perpète
- Laboratoire
de Chimie Physique des Biomolécules, University of Namur, Rue de Bruxelles, 61, 5000 Namur, Belgium
| | - Slawomir Sek
- Biological
and Chemical Research Centre, Faculty of Chemistry, University of Warsaw, Zwirki i Wigury 101, 02-089 Warsaw, Poland
| | - Carlos Alemán
- Departament
d’Enginyeria Química, EEBE, Universitat Politècnica de Catalunya, C/Eduard Maristany, 10-14, Ed. I2, 08019 Barcelona, Spain
- Barcelona
Research Center for Multiscale Science and Engineering, Universitat Politècnica de Catalunya, C/Eduard Maristany, 10-14, Ed. C, 08019 Barcelona, Spain
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56
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Pohjoismäki JLO, Forslund JME, Goffart S, Torregrosa-Muñumer R, Wanrooij S. Known Unknowns of Mammalian Mitochondrial DNA Maintenance. Bioessays 2018; 40:e1800102. [DOI: 10.1002/bies.201800102] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 06/18/2018] [Indexed: 11/06/2022]
Affiliation(s)
- Jaakko L. O. Pohjoismäki
- Department of Environmental and Biological Sciences, University of Eastern Finland; 80101 Joensuu Finland
| | | | - Steffi Goffart
- Department of Environmental and Biological Sciences, University of Eastern Finland; 80101 Joensuu Finland
| | - Rubén Torregrosa-Muñumer
- Department of Environmental and Biological Sciences, University of Eastern Finland; 80101 Joensuu Finland
| | - Sjoerd Wanrooij
- Department of Medical Biochemistry and Biophysics, Umeå University; 90187 Umeå Sweden
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57
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Jores T, Lawatscheck J, Beke V, Franz-Wachtel M, Yunoki K, Fitzgerald JC, Macek B, Endo T, Kalbacher H, Buchner J, Rapaport D. Cytosolic Hsp70 and Hsp40 chaperones enable the biogenesis of mitochondrial β-barrel proteins. J Cell Biol 2018; 217:3091-3108. [PMID: 29930205 PMCID: PMC6122992 DOI: 10.1083/jcb.201712029] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Revised: 05/04/2018] [Accepted: 05/31/2018] [Indexed: 11/22/2022] Open
Abstract
Mitochondrial β-barrel proteins are imported from the cytosol into the organelle. Jores et al. provide new insights into the early events of this process by describing an array of cytosolic chaperones and cochaperones that associate with newly synthesized β-barrel proteins and assure their optimal biogenesis. Mitochondrial β-barrel proteins are encoded in the nucleus, translated by cytosolic ribosomes, and then imported into the organelle. Recently, a detailed understanding of the intramitochondrial import pathway of β-barrel proteins was obtained. In contrast, it is still completely unclear how newly synthesized β-barrel proteins reach the mitochondrial surface in an import-competent conformation. In this study, we show that cytosolic Hsp70 chaperones and their Hsp40 cochaperones Ydj1 and Sis1 interact with newly synthesized β-barrel proteins. These interactions are highly relevant for proper biogenesis, as inhibiting the activity of the cytosolic Hsp70, preventing its docking to the mitochondrial receptor Tom70, or depleting both Ydj1 and Sis1 resulted in a significant reduction in the import of such substrates into mitochondria. Further experiments demonstrate that the interactions between β-barrel proteins and Hsp70 chaperones and their importance are conserved also in mammalian cells. Collectively, this study outlines a novel mechanism in the early events of the biogenesis of mitochondrial outer membrane β-barrel proteins.
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Affiliation(s)
- Tobias Jores
- Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, Germany
| | - Jannis Lawatscheck
- Center for Integrated Protein Science, Department Chemie, Technische Universität München, Garching, Germany
| | - Viktor Beke
- Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, Germany
| | - Mirita Franz-Wachtel
- Proteome Center Tübingen, Interfaculty Institute for Cell Biology, University of Tübingen, Tübingen, Germany
| | - Kaori Yunoki
- Faculty of Life Sciences, Kyoto Sangyo University, Kyoto, Japan
| | - Julia C Fitzgerald
- Department of Neurodegenerative Diseases and Hertie-Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany.,German Center for Neurodegenerative Diseases (DZNE), Tübingen, Germany
| | - Boris Macek
- Proteome Center Tübingen, Interfaculty Institute for Cell Biology, University of Tübingen, Tübingen, Germany
| | - Toshiya Endo
- Faculty of Life Sciences, Kyoto Sangyo University, Kyoto, Japan
| | - Hubert Kalbacher
- Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, Germany
| | - Johannes Buchner
- Center for Integrated Protein Science, Department Chemie, Technische Universität München, Garching, Germany
| | - Doron Rapaport
- Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, Germany
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58
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Höhr AIC, Lindau C, Wirth C, Qiu J, Stroud DA, Kutik S, Guiard B, Hunte C, Becker T, Pfanner N, Wiedemann N. Membrane protein insertion through a mitochondrial β-barrel gate. Science 2018; 359:359/6373/eaah6834. [PMID: 29348211 DOI: 10.1126/science.aah6834] [Citation(s) in RCA: 96] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2016] [Revised: 10/12/2017] [Accepted: 12/14/2017] [Indexed: 11/02/2022]
Abstract
The biogenesis of mitochondria, chloroplasts, and Gram-negative bacteria requires the insertion of β-barrel proteins into the outer membranes. Homologous Omp85 proteins are essential for membrane insertion of β-barrel precursors. It is unknown if precursors are threaded through the Omp85-channel interior and exit laterally or if they are translocated into the membrane at the Omp85-lipid interface. We have mapped the interaction of a precursor in transit with the mitochondrial Omp85-channel Sam50 in the native membrane environment. The precursor is translocated into the channel interior, interacts with an internal loop, and inserts into the lateral gate by β-signal exchange. Transport through the Omp85-channel interior followed by release through the lateral gate into the lipid phase may represent a basic mechanism for membrane insertion of β-barrel proteins.
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Affiliation(s)
- Alexandra I C Höhr
- Institute of Biochemistry and Molecular Biology, Centre for Biochemistry and Molecular Cell Research (ZBMZ), Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany.,Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany
| | - Caroline Lindau
- Institute of Biochemistry and Molecular Biology, Centre for Biochemistry and Molecular Cell Research (ZBMZ), Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany.,Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany
| | - Christophe Wirth
- Institute of Biochemistry and Molecular Biology, Centre for Biochemistry and Molecular Cell Research (ZBMZ), Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany
| | - Jian Qiu
- Institute of Biochemistry and Molecular Biology, Centre for Biochemistry and Molecular Cell Research (ZBMZ), Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany
| | - David A Stroud
- Institute of Biochemistry and Molecular Biology, Centre for Biochemistry and Molecular Cell Research (ZBMZ), Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany
| | - Stephan Kutik
- Institute of Biochemistry and Molecular Biology, Centre for Biochemistry and Molecular Cell Research (ZBMZ), Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany
| | - Bernard Guiard
- Centre de Génétique Moléculaire, CNRS, 91190 Gif-sur-Yvette, France
| | - Carola Hunte
- Institute of Biochemistry and Molecular Biology, Centre for Biochemistry and Molecular Cell Research (ZBMZ), Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany.,BIOSS Centre for Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany
| | - Thomas Becker
- Institute of Biochemistry and Molecular Biology, Centre for Biochemistry and Molecular Cell Research (ZBMZ), Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany.,BIOSS Centre for Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany
| | - Nikolaus Pfanner
- Institute of Biochemistry and Molecular Biology, Centre for Biochemistry and Molecular Cell Research (ZBMZ), Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany.,BIOSS Centre for Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany
| | - Nils Wiedemann
- Institute of Biochemistry and Molecular Biology, Centre for Biochemistry and Molecular Cell Research (ZBMZ), Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany.,BIOSS Centre for Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany
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59
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Chaturvedi D, Mahalakshmi R. Transmembrane β-barrels: Evolution, folding and energetics. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1859:2467-2482. [PMID: 28943271 DOI: 10.1016/j.bbamem.2017.09.020] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Revised: 09/16/2017] [Accepted: 09/19/2017] [Indexed: 12/23/2022]
Abstract
The biogenesis of transmembrane β-barrels (outer membrane proteins, or OMPs) is an elaborate multistep orchestration of the nascent polypeptide with translocases, barrel assembly machinery, and helper chaperone proteins. Several theories exist that describe the mechanism of chaperone-assisted OMP assembly in vivo and unassisted (spontaneous) folding in vitro. Structurally, OMPs of bacterial origin possess even-numbered strands, while mitochondrial β-barrels are even- and odd-stranded. Several underlying similarities between prokaryotic and eukaryotic β-barrels and their folding machinery are known; yet, the link in their evolutionary origin is unclear. While OMPs exhibit diversity in sequence and function, they share similar biophysical attributes and structure. Similarly, it is important to understand the intricate OMP assembly mechanism, particularly in eukaryotic β-barrels that have evolved to perform more complex functions. Here, we deliberate known facets of β-barrel evolution, folding, and stability, and attempt to highlight outstanding questions in β-barrel biogenesis and proteostasis.
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Affiliation(s)
- Deepti Chaturvedi
- Molecular Biophysics Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal 462066, India.
| | - Radhakrishnan Mahalakshmi
- Molecular Biophysics Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal 462066, India.
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60
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Hsueh YC, Ehmann C, Flinner N, Ladig R, Schleiff E. The plastid outer membrane localized LPTD1 is important for glycerolipid remodelling under phosphate starvation. PLANT, CELL & ENVIRONMENT 2017; 40:1643-1657. [PMID: 28433003 DOI: 10.1111/pce.12973] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Revised: 04/10/2017] [Accepted: 04/10/2017] [Indexed: 06/07/2023]
Abstract
Glycerolipid synthesis in plants is coordinated between plastids and the endoplasmic reticulum (ER). A central step within the glycerolipid synthesis is the transport of phosphatidic acid from ER to chloroplasts. The chloroplast outer envelope protein TGD4 belongs to the LptD family conserved in bacteria and plants and selectively binds and may transport phosphatidic acid. We describe a second LptD-family protein in A. thaliana (atLPTD1; At2g44640) characterized by a barrel domain with an amino-acid signature typical for cyanobacterial LptDs. It forms a cation selective channel in vitro with a diameter of about 9 Å. atLPTD1 levels are induced under phosphate starvation. Plants expressing an RNAi construct against atLPTD1 show a growth phenotype under normal conditions. Expressing the RNAi against atLPTD1 in the tgd4-1 background renders the plants more sensitive to light stress or phosphate limitation than the individual mutants. Moreover, lipid analysis revealed that digalactosyldiacylglycerol and sulfoquinovosyldiacylglycerol levels remain constant in the RNAi mutants under phosphate starvation, while these two lipids are enhanced in wild-type. Based on our results, we propose a function of atLPTD1 in the transport of lipids from ER to chloroplast under phosphate starvation, which is combinatory with the function of TGD4.
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Affiliation(s)
- Yi-Ching Hsueh
- Department of Biosciences, Molecular Cell Biology of Plants, Goethe University, Max von Laue Str. 9, 60438, Frankfurt am Main, Germany
- Department of Physics, Syracuse University, 201 Physics Bldg., Syracuse, New York, NY, 13244-1130, USA
| | - Christian Ehmann
- Department of Biosciences, Molecular Cell Biology of Plants, Goethe University, Max von Laue Str. 9, 60438, Frankfurt am Main, Germany
| | - Nadine Flinner
- Department of Biosciences, Molecular Cell Biology of Plants, Goethe University, Max von Laue Str. 9, 60438, Frankfurt am Main, Germany
- Frankfurt Institute for Advanced Studies (FIAS), Ruth-Moufang-Straße 1, 60438, Frankfurt am Main, Germany
| | - Roman Ladig
- Department of Biosciences, Molecular Cell Biology of Plants, Goethe University, Max von Laue Str. 9, 60438, Frankfurt am Main, Germany
| | - Enrico Schleiff
- Department of Biosciences, Molecular Cell Biology of Plants, Goethe University, Max von Laue Str. 9, 60438, Frankfurt am Main, Germany
- Cluster of Excellence Frankfurt, Goethe University, Max von Laue Str. 9, 60438, Frankfurt am Main, Germany
- Buchman Institute of Molecular Life Sciences, Goethe University, Max von Laue Str. 15, 60438, Frankfurt am Main, Germany
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61
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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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62
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Affiliation(s)
- Tobias Jores
- Interfaculty Institute of Biochemistry; University of Tuebingen; Germany
| | - Doron Rapaport
- Interfaculty Institute of Biochemistry; University of Tuebingen; Germany
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63
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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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Abstract
Mitochondria are essential organelles with numerous functions in cellular metabolism and homeostasis. Most of the >1,000 different mitochondrial proteins are synthesized as precursors in the cytosol and are imported into mitochondria by five transport pathways. The protein import machineries of the mitochondrial membranes and aqueous compartments reveal a remarkable variability of mechanisms for protein recognition, translocation, and sorting. The protein translocases do not operate as separate entities but are connected to each other and to machineries with functions in energetics, membrane organization, and quality control. Here, we discuss the versatility and dynamic organization of the mitochondrial protein import machineries. Elucidating the molecular mechanisms of mitochondrial protein translocation is crucial for understanding the integration of protein translocases into a large network that controls organelle biogenesis, function, and dynamics.
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Affiliation(s)
- Nils Wiedemann
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, and BIOSS Centre for Biological Signaling Studies, University of Freiburg, 79104 Freiburg, Germany; ,
| | - Nikolaus Pfanner
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, and BIOSS Centre for Biological Signaling Studies, University of Freiburg, 79104 Freiburg, Germany; ,
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65
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Bruggisser J, Käser S, Mani J, Schneider A. Biogenesis of a Mitochondrial Outer Membrane Protein in Trypanosoma brucei: TARGETING SIGNAL AND DEPENDENCE ON A UNIQUE BIOGENESIS FACTOR. J Biol Chem 2017; 292:3400-3410. [PMID: 28100781 DOI: 10.1074/jbc.m116.755983] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Revised: 01/16/2017] [Indexed: 11/06/2022] Open
Abstract
The mitochondrial outer membrane (OM) contains single and multiple membrane-spanning proteins that need to contain signals that ensure correct targeting and insertion into the OM. The biogenesis of such proteins has so far essentially only been studied in yeast and related organisms. Here we show that POMP10, an OM protein of the early diverging protozoan Trypanosoma brucei, is signal-anchored. Transgenic cells expressing variants of POMP10 fused to GFP demonstrate that the N-terminal membrane-spanning domain flanked by a few positively charged or neutral residues is both necessary and sufficient for mitochondrial targeting. Carbonate extraction experiments indicate that although the presence of neutral instead of positively charged residues did not interfere with POMP10 localization, it weakened its interaction with the OM. Expression of GFP-tagged POMP10 in inducible RNAi cell lines shows that its mitochondrial localization depends on pATOM36 but does not require Sam50 or ATOM40, the trypanosomal analogue of the Tom40 import pore. pATOM36 is a kinetoplastid-specific OM protein that has previously been implicated in the assembly of OM proteins and in mitochondrial DNA inheritance. In summary, our results show that although the features of the targeting signal in signal-anchored proteins are widely conserved, the protein machinery that mediates their biogenesis is not.
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Affiliation(s)
- Julia Bruggisser
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, CH-3012 Bern, Switzerland
| | - Sandro Käser
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, CH-3012 Bern, Switzerland
| | - Jan Mani
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, CH-3012 Bern, Switzerland
| | - André Schneider
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, CH-3012 Bern, Switzerland.
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Tribensky A, Graf AW, Diehl M, Fleck W, Przyborski JM. Trafficking of PfExp1 to the parasitophorous vacuolar membrane of Plasmodium falciparum is independent of protein folding and the PTEX translocon. Cell Microbiol 2017; 19. [PMID: 27892646 DOI: 10.1111/cmi.12710] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Revised: 10/19/2016] [Accepted: 11/24/2016] [Indexed: 12/13/2022]
Abstract
Having entered the mature human erythrocyte, the malaria parasite survives and propagates within a parasitophorous vacuole, a membrane-bound compartment separating the parasite from the host cell cytosol. The bounding membrane of this vacuole, referred to as the parasitophorous vacuolar membrane (PVM), contains parasite-encoded proteins, but how these membrane proteins are trafficked to the PVM remains unknown. Here, we have studied the trafficking of PfExp1 to the PVM. We find that trafficking of PfExp1 to the PVM is independent of the folding state of the protein and also continues unabated upon inactivation of the PVM translocon Plasmodium Translocon of Exported proteins (PTEX). Our data strongly suggest that the trafficking of membrane proteins to the PVM occurs by as yet unknown mechanism, potentially unique to Plasmodium.
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Affiliation(s)
- Anke Tribensky
- Department of Parasitology, University of Marburg, Marburg, Germany
| | - Andreas W Graf
- Department of Parasitology, University of Marburg, Marburg, Germany
| | - Mathias Diehl
- Department of Parasitology, University of Marburg, Marburg, Germany
| | - Wiebke Fleck
- Department of Parasitology, University of Marburg, Marburg, Germany
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Pfitzner AK, Steblau N, Ulrich T, Oberhettinger P, Autenrieth IB, Schütz M, Rapaport D. Mitochondrial-bacterial hybrids of BamA/Tob55 suggest variable requirements for the membrane integration of β-barrel proteins. Sci Rep 2016; 6:39053. [PMID: 27982054 PMCID: PMC5159795 DOI: 10.1038/srep39053] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Accepted: 11/16/2016] [Indexed: 11/10/2022] Open
Abstract
β-Barrel proteins are found in the outer membrane (OM) of Gram-negative bacteria, chloroplasts and mitochondria. The assembly of these proteins into the corresponding OM is facilitated by a dedicated protein complex that contains a central conserved β-barrel protein termed BamA in bacteria and Tob55/Sam50 in mitochondria. BamA and Tob55 consist of a membrane-integral C-terminal domain that forms a β-barrel pore and a soluble N-terminal portion comprised of one (in Tob55) or five (in BamA) polypeptide transport-associated (POTRA) domains. Currently the functional significance of this difference and whether the homology between BamA and Tob55 can allow them to replace each other are unclear. To address these issues we constructed hybrid Tob55/BamA proteins with differently configured N-terminal POTRA domains. We observed that constructs harboring a heterologous C-terminal domain could not functionally replace the bacterial BamA or the mitochondrial Tob55 demonstrating species-specific requirements. Interestingly, the various hybrid proteins in combination with the bacterial chaperones Skp or SurA supported to a variable extent the assembly of bacterial β-barrel proteins into the mitochondrial OM. Collectively, our findings suggest that the membrane assembly of various β-barrel proteins depends to a different extent on POTRA domains and periplasmic chaperones.
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Affiliation(s)
| | - Nadja Steblau
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, 72076 Tübingen, Germany
| | - Thomas Ulrich
- Interfaculty Institute of Biochemistry, University of Tübingen, 72076 Tübingen, Germany
| | - Philipp Oberhettinger
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, 72076 Tübingen, Germany
| | - Ingo B Autenrieth
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, 72076 Tübingen, Germany
| | - Monika Schütz
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, 72076 Tübingen, Germany
| | - Doron Rapaport
- Interfaculty Institute of Biochemistry, University of Tübingen, 72076 Tübingen, Germany
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Wasilewski M, Chojnacka K, Chacinska A. Protein trafficking at the crossroads to mitochondria. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2016; 1864:125-137. [PMID: 27810356 DOI: 10.1016/j.bbamcr.2016.10.019] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Revised: 10/25/2016] [Accepted: 10/27/2016] [Indexed: 12/14/2022]
Abstract
Mitochondria are central power stations in the cell, which additionally serve as metabolic hubs for a plethora of anabolic and catabolic processes. The sustained function of mitochondria requires the precisely controlled biogenesis and expression coordination of proteins that originate from the nuclear and mitochondrial genomes. Accuracy of targeting, transport and assembly of mitochondrial proteins is also needed to avoid deleterious effects on protein homeostasis in the cell. Checkpoints of mitochondrial protein transport can serve as signals that provide information about the functional status of the organelles. In this review, we summarize recent advances in our understanding of mitochondrial protein transport and discuss examples that involve communication with the nucleus and cytosol.
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Affiliation(s)
- Michal Wasilewski
- International Institute of Molecular and Cell Biology in Warsaw, Poland.
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