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Kohler V, Kohler A, Berglund LL, Hao X, Gersing S, Imhof A, Nyström T, Höög JL, Ott M, Andréasson C, Büttner S. Nuclear Hsp104 safeguards the dormant translation machinery during quiescence. Nat Commun 2024; 15:315. [PMID: 38182580 PMCID: PMC10770042 DOI: 10.1038/s41467-023-44538-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Accepted: 12/15/2023] [Indexed: 01/07/2024] Open
Abstract
The resilience of cellular proteostasis declines with age, which drives protein aggregation and compromises viability. The nucleus has emerged as a key quality control compartment that handles misfolded proteins produced by the cytosolic protein biosynthesis system. Here, we find that age-associated metabolic cues target the yeast protein disaggregase Hsp104 to the nucleus to maintain a functional nuclear proteome during quiescence. The switch to respiratory metabolism and the accompanying decrease in translation rates direct cytosolic Hsp104 to the nucleus to interact with latent translation initiation factor eIF2 and to suppress protein aggregation. Hindering Hsp104 from entering the nucleus in quiescent cells results in delayed re-entry into the cell cycle due to compromised resumption of protein synthesis. In sum, we report that cytosolic-nuclear partitioning of the Hsp104 disaggregase is a critical mechanism to protect the latent protein synthesis machinery during quiescence in yeast, ensuring the rapid restart of translation once nutrients are replenished.
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Affiliation(s)
- Verena Kohler
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 10691, Stockholm, Sweden
- Institute of Molecular Biosciences, University of Graz, 8010, Graz, Austria
- Department of Molecular Biology, Umeå University, 90187, Umeå, Sweden
| | - Andreas Kohler
- Institute of Molecular Biosciences, University of Graz, 8010, Graz, Austria
- Department of Biochemistry and Biophysics, Stockholm University, 10691, Stockholm, Sweden
- Department of Medical Biochemistry and Biophysics, Umeå University, 90187, Umeå, Sweden
| | - Lisa Larsson Berglund
- Department of Chemistry and Molecular Biology, University of Gothenburg, 40530, Gothenburg, Sweden
| | - Xinxin Hao
- Department of Microbiology and Immunology, University of Gothenburg, 40530, Gothenburg, Sweden
| | - Sarah Gersing
- The Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, 1165, Copenhagen, Denmark
| | - Axel Imhof
- Biomedical Center Munich, Faculty of Medicine, Ludwig Maximilian University of Munich, 82152, Planegg-Martinsried, Germany
| | - Thomas Nyström
- Department of Microbiology and Immunology, University of Gothenburg, 40530, Gothenburg, Sweden
| | - Johanna L Höög
- Department of Chemistry and Molecular Biology, University of Gothenburg, 40530, Gothenburg, Sweden
| | - Martin Ott
- Department of Biochemistry and Biophysics, Stockholm University, 10691, Stockholm, Sweden
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, 40530, Gothenburg, Sweden
| | - Claes Andréasson
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 10691, Stockholm, Sweden.
| | - Sabrina Büttner
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 10691, Stockholm, Sweden.
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Kohler V, Arunagiri A, Ventura S, Kroschwald S, Ranganathan S. Editorial: Molecular determinants of protein assemblies in health and disease, Volume II. Front Mol Biosci 2023; 10:1343082. [PMID: 38146534 PMCID: PMC10749430 DOI: 10.3389/fmolb.2023.1343082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Accepted: 11/27/2023] [Indexed: 12/27/2023] Open
Affiliation(s)
- Verena Kohler
- Department of Molecular Biology, Faculty of Medicine, Umeå University, Umeå, Sweden
| | - Anoop Arunagiri
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI, United States
| | - Salvador Ventura
- Departament de Bioquímica i Biologia Molecular, Institut de Biotecnologia i de Biomedicina (IBB), Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Sonja Kroschwald
- Department of Biology, Institute of Biochemistry, Zürich, Switzerland
| | - Srivastav Ranganathan
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, United States
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3
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Keuenhof KS, Kohler V, Broeskamp F, Panagaki D, Speese SD, Büttner S, Höög JL. Nuclear envelope budding and its cellular functions. Nucleus 2023; 14:2178184. [PMID: 36814098 PMCID: PMC9980700 DOI: 10.1080/19491034.2023.2178184] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Accepted: 02/03/2023] [Indexed: 02/24/2023] Open
Abstract
The nuclear pore complex (NPC) has long been assumed to be the sole route across the nuclear envelope, and under normal homeostatic conditions it is indeed the main mechanism of nucleo-cytoplasmic transport. However, it has also been known that e.g. herpesviruses cross the nuclear envelope utilizing a pathway entitled nuclear egress or envelopment/de-envelopment. Despite this, a thread of observations suggests that mechanisms similar to viral egress may be transiently used also in healthy cells. It has since been proposed that mechanisms like nuclear envelope budding (NEB) can facilitate the transport of RNA granules, aggregated proteins, inner nuclear membrane proteins, and mis-assembled NPCs. Herein, we will summarize the known roles of NEB as a physiological and intrinsic cellular feature and highlight the many unanswered questions surrounding these intriguing nuclear events.
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Affiliation(s)
| | - Verena Kohler
- Institute of Molecular Biosciences, University of Graz, Austria
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Sweden
| | - Filomena Broeskamp
- Department for Chemistry and Molecular biology, University of Gothenburg, Sweden
| | - Dimitra Panagaki
- Department for Chemistry and Molecular biology, University of Gothenburg, Sweden
| | - Sean D. Speese
- Knight Cancer Early Detection Advanced Research Center, Oregon Health and Science University, 2720 S Moody Ave, Portland, OR, 97201, USA
| | - Sabrina Büttner
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Sweden
| | - Johanna L. Höög
- Department for Chemistry and Molecular biology, University of Gothenburg, Sweden
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Kohler A, Carlström A, Nolte H, Kohler V, Jung SJ, Sridhara S, Tatsuta T, Berndtsson J, Langer T, Ott M. Early fate decision for mitochondrially encoded proteins by a molecular triage. Mol Cell 2023; 83:3470-3484.e8. [PMID: 37751741 DOI: 10.1016/j.molcel.2023.09.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 07/12/2023] [Accepted: 09/05/2023] [Indexed: 09/28/2023]
Abstract
Folding of newly synthesized proteins poses challenges for a functional proteome. Dedicated protein quality control (PQC) systems either promote the folding of nascent polypeptides at ribosomes or, if this fails, ensure their degradation. Although well studied for cytosolic protein biogenesis, it is not understood how these processes work for mitochondrially encoded proteins, key subunits of the oxidative phosphorylation (OXPHOS) system. Here, we identify dedicated hubs in proximity to mitoribosomal tunnel exits coordinating mitochondrial protein biogenesis and quality control. Conserved prohibitin (PHB)/m-AAA protease supercomplexes and the availability of assembly chaperones determine the fate of newly synthesized proteins by molecular triaging. The localization of these competing activities in the vicinity of the mitoribosomal tunnel exit allows for a prompt decision on whether newly synthesized proteins are fed into OXPHOS assembly or are degraded.
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Affiliation(s)
- Andreas Kohler
- Department of Biochemistry and Biophysics, Stockholm University, 106 91 Stockholm, Sweden; Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria
| | - Andreas Carlström
- Department of Biochemistry and Biophysics, Stockholm University, 106 91 Stockholm, Sweden
| | - Hendrik Nolte
- Max Planck Institute for Biology of Ageing, 50931 Cologne, Germany
| | - Verena Kohler
- Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria; Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 106 91 Stockholm, Sweden
| | - Sung-Jun Jung
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, 405 30 Gothenburg, Sweden
| | - Sagar Sridhara
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, 405 30 Gothenburg, Sweden
| | - Takashi Tatsuta
- Max Planck Institute for Biology of Ageing, 50931 Cologne, Germany
| | - Jens Berndtsson
- Department of Biochemistry and Biophysics, Stockholm University, 106 91 Stockholm, Sweden
| | - Thomas Langer
- Max Planck Institute for Biology of Ageing, 50931 Cologne, Germany; Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, 50931 Cologne, Germany.
| | - Martin Ott
- Department of Biochemistry and Biophysics, Stockholm University, 106 91 Stockholm, Sweden; Department of Medical Biochemistry and Cell Biology, University of Gothenburg, 405 30 Gothenburg, Sweden.
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Vazquez‐Calvo C, Kohler V, Höög JL, Büttner S, Ott M. Newly imported proteins in mitochondria are particularly sensitive to aggregation. Acta Physiol (Oxf) 2023; 238:e13985. [PMID: 37171464 PMCID: PMC10909475 DOI: 10.1111/apha.13985] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 04/20/2023] [Accepted: 05/09/2023] [Indexed: 05/13/2023]
Abstract
AIM A functional proteome is essential for life and maintained by protein quality control (PQC) systems in the cytosol and organelles. Protein aggregation is an indicator of a decline of PQC linked to aging and disease. Mitochondrial PQC is critical to maintain mitochondrial function and thus cellular fitness. How mitochondria handle aggregated proteins is not well understood. Here we tested how the metabolic status impacts on formation and clearance of aggregates within yeast mitochondria and assessed which proteins are particularly sensitive to denaturation. METHODS Confocal microscopy, electron microscopy, immunoblotting and genetics were applied to assess mitochondrial aggregate handling in response to heat shock and ethanol using the mitochondrial disaggregase Hsp78 as a marker for protein aggregates. RESULTS We show that aggregates formed upon heat or ethanol stress with different dynamics depending on the metabolic state. While fermenting cells displayed numerous small aggregates that coalesced into one large foci that was resistant to clearance, respiring cells showed less aggregates and cleared these aggregates more efficiently. Acute inhibition of mitochondrial translation had no effect, while preventing protein import into mitochondria by inhibition of cytosolic translation prevented aggregate formation. CONCLUSION Collectively, our data show that the metabolic state of the cells impacts the dynamics of aggregate formation and clearance, and that mainly newly imported and not yet assembled proteins are prone to form aggregates. Because mitochondrial functionality is crucial for cellular metabolism, these results highlight the importance of efficient protein biogenesis to maintain the mitochondrial proteome operational during metabolic adaptations and cellular stress.
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Affiliation(s)
- Carmela Vazquez‐Calvo
- Department of Biochemistry and BiophysicsStockholm UniversityStockholmSweden
- Department of Molecular Biosciences, The Wenner‐Gren InstituteStockholm UniversityStockholmSweden
| | - Verena Kohler
- Department of Molecular Biosciences, The Wenner‐Gren InstituteStockholm UniversityStockholmSweden
- Institute of Molecular BiosciencesUniversity of GrazGrazAustria
| | - Johanna L. Höög
- Department of Chemistry and Molecular BiologyUniversity of GothenburgGothenburgSweden
| | - Sabrina Büttner
- Department of Molecular Biosciences, The Wenner‐Gren InstituteStockholm UniversityStockholmSweden
| | - Martin Ott
- Department of Biochemistry and BiophysicsStockholm UniversityStockholmSweden
- Department of Medical Biochemistry and Cell BiologyUniversity of GothenburgGothenburgSweden
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Kohler V, Andréasson C. Reversible protein assemblies in the proteostasis network in health and disease. Front Mol Biosci 2023; 10:1155521. [PMID: 37021114 PMCID: PMC10067754 DOI: 10.3389/fmolb.2023.1155521] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Accepted: 03/09/2023] [Indexed: 04/07/2023] Open
Abstract
While proteins populating their native conformations constitute the functional entities of cells, protein aggregates are traditionally associated with cellular dysfunction, stress and disease. During recent years, it has become clear that large aggregate-like protein condensates formed via liquid-liquid phase separation age into more solid aggregate-like particles that harbor misfolded proteins and are decorated by protein quality control factors. The constituent proteins of the condensates/aggregates are disentangled by protein disaggregation systems mainly based on Hsp70 and AAA ATPase Hsp100 chaperones prior to their handover to refolding and degradation systems. Here, we discuss the functional roles that condensate formation/aggregation and disaggregation play in protein quality control to maintain proteostasis and why it matters for understanding health and disease.
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Affiliation(s)
- Verena Kohler
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Claes Andréasson
- Department of Molecular Biosciences, Stockholm University, Stockholm, Sweden
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Kohler V, Braun RJ, Aufschnaiter A. Editorial: Mitochondria as a hub for neurodegenerative disorders. Front Mol Neurosci 2023; 16:1147468. [PMID: 36814968 PMCID: PMC9939891 DOI: 10.3389/fnmol.2023.1147468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Accepted: 01/23/2023] [Indexed: 02/08/2023] Open
Affiliation(s)
- Verena Kohler
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Ralf J. Braun
- Research Division for Neurodegenerative Diseases, Center for Biosciences, Department of Medicine, Faculty of Medicine and Dentistry, Danube Private University, Krems an der Donau, Austria
| | - Andreas Aufschnaiter
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
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Kroschwald S, Arunagiri A, Ventura S, Ranganathan S, Kohler V. Editorial: Molecular determinants of protein assemblies in health and disease. Front Mol Biosci 2022; 9:1107686. [PMID: 36589240 PMCID: PMC9795166 DOI: 10.3389/fmolb.2022.1107686] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Accepted: 12/05/2022] [Indexed: 12/15/2022] Open
Affiliation(s)
- Sonja Kroschwald
- Institut für Biochemie, ETH Zurich, Zurich, Switzerland,*Correspondence: Sonja Kroschwald, ; Anoop Arunagiri, ; Salvador Ventura, ; Srivastav Ranganathan, ; Verena Kohler,
| | - Anoop Arunagiri
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI, United States,*Correspondence: Sonja Kroschwald, ; Anoop Arunagiri, ; Salvador Ventura, ; Srivastav Ranganathan, ; Verena Kohler,
| | - Salvador Ventura
- Institut de Biotecnologia i Biomedicina and Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, Bellaterra, Barcelona, Spain,*Correspondence: Sonja Kroschwald, ; Anoop Arunagiri, ; Salvador Ventura, ; Srivastav Ranganathan, ; Verena Kohler,
| | - Srivastav Ranganathan
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, United States,*Correspondence: Sonja Kroschwald, ; Anoop Arunagiri, ; Salvador Ventura, ; Srivastav Ranganathan, ; Verena Kohler,
| | - Verena Kohler
- Institute of Molecular Biosciences, University of Graz, Graz, Styria, Austria,*Correspondence: Sonja Kroschwald, ; Anoop Arunagiri, ; Salvador Ventura, ; Srivastav Ranganathan, ; Verena Kohler,
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Peselj C, Ebrahimi M, Broeskamp F, Prokisch S, Habernig L, Alvarez-Guerra I, Kohler V, Vögtle FN, Büttner S. Sterol Metabolism Differentially Contributes to Maintenance and Exit of Quiescence. Front Cell Dev Biol 2022; 10:788472. [PMID: 35237594 PMCID: PMC8882848 DOI: 10.3389/fcell.2022.788472] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2021] [Accepted: 01/20/2022] [Indexed: 01/01/2023] Open
Abstract
Nutrient starvation initiates cell cycle exit and entry into quiescence, a reversible, non-proliferative state characterized by stress tolerance, longevity and large-scale remodeling of subcellular structures. Depending on the nature of the depleted nutrient, yeast cells are assumed to enter heterogeneous quiescent states with unique but mostly unexplored characteristics. Here, we show that storage and consumption of neutral lipids in lipid droplets (LDs) differentially impacts the regulation of quiescence driven by glucose or phosphate starvation. Upon prolonged glucose exhaustion, LDs were degraded in the vacuole via Atg1-dependent lipophagy. In contrast, yeast cells entering quiescence due to phosphate exhaustion massively over-accumulated LDs that clustered at the vacuolar surface but were not engulfed via lipophagy. Excessive LD biogenesis required contact formation between the endoplasmic reticulum and the vacuole at nucleus-vacuole junctions and was accompanied by a shift of the cellular lipid profile from membrane towards storage lipids, driven by a transcriptional upregulation of enzymes generating neutral lipids, in particular sterol esters. Importantly, sterol ester biogenesis was critical for long-term survival of phosphate-exhausted cells and supported rapid quiescence exit upon nutrient replenishment, but was dispensable for survival and regrowth of glucose-exhausted cells. Instead, these cells relied on de novo synthesis of sterols and fatty acids for quiescence exit and regrowth. Phosphate-exhausted cells efficiently mobilized storage lipids to support several rounds of cell division even in presence of inhibitors of fatty acid and sterol biosynthesis. In sum, our results show that neutral lipid biosynthesis and mobilization to support quiescence maintenance and exit is tailored to the respective nutrient scarcity.
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Affiliation(s)
- Carlotta Peselj
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Mahsa Ebrahimi
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Filomena Broeskamp
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Simon Prokisch
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Lukas Habernig
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Irene Alvarez-Guerra
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Verena Kohler
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - F.-Nora Vögtle
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Heidelberg University, Heidelberg, Germany
- Network Aging Research, Heidelberg University, Heidelberg, Germany
- CIBSS - Centre for Integrative Biological Signalling Studies, University of Freiburg, Freiburg, Germany
| | - Sabrina Büttner
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
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Berger TMI, Kohler V, Reisenbichler A, Gubensäk N, Keller W. Structural and functional characterization of a DNA binding protein of pIP501 – a broad host-range plasmid. Acta Crystallogr A Found Adv 2021. [DOI: 10.1107/s0108767321085834] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Panagaki D, Croft JT, Keuenhof K, Larsson Berglund L, Andersson S, Kohler V, Büttner S, Tamás MJ, Nyström T, Neutze R, Höög JL. Nuclear envelope budding is a response to cellular stress. Proc Natl Acad Sci U S A 2021; 118:e2020997118. [PMID: 34290138 PMCID: PMC8325156 DOI: 10.1073/pnas.2020997118] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Nuclear envelope budding (NEB) is a recently discovered alternative pathway for nucleocytoplasmic communication distinct from the movement of material through the nuclear pore complex. Through quantitative electron microscopy and tomography, we demonstrate how NEB is evolutionarily conserved from early protists to human cells. In the yeast Saccharomyces cerevisiae, NEB events occur with higher frequency during heat shock, upon exposure to arsenite or hydrogen peroxide, and when the proteasome is inhibited. Yeast cells treated with azetidine-2-carboxylic acid, a proline analog that induces protein misfolding, display the most dramatic increase in NEB, suggesting a causal link to protein quality control. This link was further supported by both localization of ubiquitin and Hsp104 to protein aggregates and NEB events, and the evolution of these structures during heat shock. We hypothesize that NEB is part of normal cellular physiology in a vast range of species and that in S. cerevisiae NEB comprises a stress response aiding the transport of protein aggregates across the nuclear envelope.
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Affiliation(s)
- Dimitra Panagaki
- Department of Chemistry and Molecular Biology, University of Gothenburg, 405 30 Gothenburg, Sweden
| | - Jacob T Croft
- Department of Chemistry and Molecular Biology, University of Gothenburg, 405 30 Gothenburg, Sweden
| | - Katharina Keuenhof
- Department of Chemistry and Molecular Biology, University of Gothenburg, 405 30 Gothenburg, Sweden
| | - Lisa Larsson Berglund
- Department of Chemistry and Molecular Biology, University of Gothenburg, 405 30 Gothenburg, Sweden
| | - Stefanie Andersson
- Department of Chemistry and Molecular Biology, University of Gothenburg, 405 30 Gothenburg, Sweden
| | - Verena Kohler
- Department of Molecular Bioscienses, The Wenner-Gren Institute, Stockholm University, 106 91 Stockholm, Sweden
| | - Sabrina Büttner
- Department of Molecular Bioscienses, The Wenner-Gren Institute, Stockholm University, 106 91 Stockholm, Sweden
| | - Markus J Tamás
- Department of Chemistry and Molecular Biology, University of Gothenburg, 405 30 Gothenburg, Sweden
| | - Thomas Nyström
- Department of Microbiology and Immunology, University of Gothenburg, 405 30 Gothenburg, Sweden
| | - Richard Neutze
- Department of Chemistry and Molecular Biology, University of Gothenburg, 405 30 Gothenburg, Sweden
| | - Johanna L Höög
- Department of Chemistry and Molecular Biology, University of Gothenburg, 405 30 Gothenburg, Sweden;
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Abstract
Chaperones of the 70 kDa heat shock protein (Hsp70) superfamily are key components of the cellular proteostasis system. Together with its co-chaperones, Hsp70 forms proteostasis subsystems that antagonize protein damage during physiological and stress conditions. This function stems from highly regulated binding and release cycles of protein substrates, which results in a flow of unfolded, partially folded and misfolded species through the Hsp70 subsystem. Specific factors control how Hsp70 makes decisions regarding folding and degradation fates of the substrate proteins. In this review, we summarize how the flow of Hsp70 substrates is controlled in the cell with special emphasis on recent advances regarding substrate release mechanisms.
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Affiliation(s)
- Verena Kohler
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, S-106 91 Stockholm, Sweden
| | - Claes Andréasson
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, S-106 91 Stockholm, Sweden
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13
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Tosal-Castano S, Peselj C, Kohler V, Habernig L, Berglund LL, Ebrahimi M, Vögtle FN, Höög J, Andréasson C, Büttner S. Snd3 controls nucleus-vacuole junctions in response to glucose signaling. Cell Rep 2021; 34:108637. [PMID: 33472077 DOI: 10.1016/j.celrep.2020.108637] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 12/08/2020] [Accepted: 12/21/2020] [Indexed: 12/29/2022] Open
Abstract
Membrane contact sites facilitate the exchange of metabolites between organelles to support interorganellar communication. The nucleus-vacuole junctions (NVJs) establish physical contact between the perinuclear endoplasmic reticulum (ER) and the vacuole. Although the NVJ tethers are known, how NVJ abundance and composition are controlled in response to metabolic cues remains elusive. Here, we identify the ER protein Snd3 as central factor for NVJ formation. Snd3 interacts with NVJ tethers, supports their targeting to the contacts, and is essential for NVJ formation. Upon glucose exhaustion, Snd3 relocalizes from the ER to NVJs and promotes contact expansion regulated by central glucose signaling pathways. Glucose replenishment induces the rapid dissociation of Snd3 from the NVJs, preceding the slow disassembly of the junctions. In sum, this study identifies a key factor required for formation and regulation of NVJs and provides a paradigm for metabolic control of membrane contact sites.
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Affiliation(s)
- Sergi Tosal-Castano
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Svante Arrhenius väg 20C, 10691 Stockholm, Sweden
| | - Carlotta Peselj
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Svante Arrhenius väg 20C, 10691 Stockholm, Sweden
| | - Verena Kohler
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Svante Arrhenius väg 20C, 10691 Stockholm, Sweden
| | - Lukas Habernig
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Svante Arrhenius väg 20C, 10691 Stockholm, Sweden
| | - Lisa Larsson Berglund
- Department of Chemistry and Molecular Biology, University of Gothenburg, Medicinaregatan 9C, 41390 Gothenburg, Sweden
| | - Mahsa Ebrahimi
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Svante Arrhenius väg 20C, 10691 Stockholm, Sweden
| | - F-Nora Vögtle
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, Stefan-Meier-Straße 17, 79104 Freiburg, Germany; Centre for Integrative Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany
| | - Johanna Höög
- Department of Chemistry and Molecular Biology, University of Gothenburg, Medicinaregatan 9C, 41390 Gothenburg, Sweden
| | - Claes Andréasson
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Svante Arrhenius väg 20C, 10691 Stockholm, Sweden
| | - Sabrina Büttner
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Svante Arrhenius väg 20C, 10691 Stockholm, Sweden; Institute of Molecular Biosciences, University of Graz, Humboldtstraße 50, 8010 Graz, Austria.
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14
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Kohler V, Büttner S. Remodelling of Nucleus-Vacuole Junctions During Metabolic and Proteostatic Stress. Contact (Thousand Oaks) 2021; 4:25152564211016608. [PMID: 34124572 PMCID: PMC7610967 DOI: 10.1177/25152564211016608] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 04/21/2021] [Accepted: 04/21/2021] [Indexed: 12/18/2022]
Abstract
Cellular adaptation to stress and metabolic cues requires a coordinated response of different intracellular compartments, separated by semipermeable membranes. One way to facilitate interorganellar communication is via membrane contact sites, physical bridges between opposing organellar membranes formed by an array of tethering machineries. These contact sites are highly dynamic and establish an interconnected organellar network able to quickly respond to external and internal stress by changing size, abundance and molecular architecture. Here, we discuss recent work on nucleus-vacuole junctions, connecting yeast vacuoles with the nucleus. Appearing as small, single foci in mitotic cells, these contacts expand into one enlarged patch upon nutrient exhaustion and entry into quiescence or can be shaped into multiple large foci essential to sustain viability upon proteostatic stress at the nuclear envelope. We highlight the remarkable plasticity and rapid remodelling of these contact sites upon metabolic or proteostatic stress and their emerging importance for cellular fitness.
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Affiliation(s)
- Verena Kohler
- Department of Molecular Biosciences, The Wenner‐Gren Institute, Stockholm University, Stockholm, Sweden
| | - Sabrina Büttner
- Department of Molecular Biosciences, The Wenner‐Gren Institute, Stockholm University, Stockholm, Sweden
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
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15
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Berndtsson J, Kohler A, Rathore S, Marin‐Buera L, Dawitz H, Diessl J, Kohler V, Barrientos A, Büttner S, Fontanesi F, Ott M. Respiratory supercomplexes enhance electron transport by decreasing cytochrome c diffusion distance. EMBO Rep 2020; 21:e51015. [PMID: 33016568 PMCID: PMC7726804 DOI: 10.15252/embr.202051015] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Revised: 09/02/2020] [Accepted: 09/10/2020] [Indexed: 01/03/2023] Open
Abstract
Respiratory chains are crucial for cellular energy conversion and consist of multi-subunit complexes that can assemble into supercomplexes. These structures have been intensively characterized in various organisms, but their physiological roles remain unclear. Here, we elucidate their function by leveraging a high-resolution structural model of yeast respiratory supercomplexes that allowed us to inhibit supercomplex formation by mutation of key residues in the interaction interface. Analyses of a mutant defective in supercomplex formation, which still contains fully functional individual complexes, show that the lack of supercomplex assembly delays the diffusion of cytochrome c between the separated complexes, thus reducing electron transfer efficiency. Consequently, competitive cellular fitness is severely reduced in the absence of supercomplex formation and can be restored by overexpression of cytochrome c. In sum, our results establish how respiratory supercomplexes increase the efficiency of cellular energy conversion, thereby providing an evolutionary advantage for aerobic organisms.
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Affiliation(s)
- Jens Berndtsson
- Department of Biochemistry and BiophysicsStockholm UniversityStockholmSweden
| | - Andreas Kohler
- Department of Biochemistry and BiophysicsStockholm UniversityStockholmSweden
| | - Sorbhi Rathore
- Department of Biochemistry and BiophysicsStockholm UniversityStockholmSweden
| | - Lorena Marin‐Buera
- Department of Biochemistry and BiophysicsStockholm UniversityStockholmSweden
| | - Hannah Dawitz
- Department of Biochemistry and BiophysicsStockholm UniversityStockholmSweden
| | - Jutta Diessl
- Department of Molecular BiosciencesThe Wenner‐Gren InstituteStockholm UniversityStockholmSweden
| | - Verena Kohler
- Department of Molecular BiosciencesThe Wenner‐Gren InstituteStockholm UniversityStockholmSweden
| | - Antoni Barrientos
- Department of NeurologyMiller School of MedicineUniversity of MiamiMiamiFLUSA
- Department of Biochemistry and Molecular BiologyMiller School of MedicineUniversity of MiamiMiamiFLUSA
| | - Sabrina Büttner
- Department of Molecular BiosciencesThe Wenner‐Gren InstituteStockholm UniversityStockholmSweden
- Institute of Molecular BiosciencesUniversity of GrazGrazAustria
| | - Flavia Fontanesi
- Department of Biochemistry and Molecular BiologyMiller School of MedicineUniversity of MiamiMiamiFLUSA
| | - Martin Ott
- Department of Biochemistry and BiophysicsStockholm UniversityStockholmSweden
- Department of Medical Biochemistry and Cell BiologyUniversity of GothenburgGothenburgSweden
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16
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Kohler V, Aufschnaiter A, Büttner S. Closing the Gap: Membrane Contact Sites in the Regulation of Autophagy. Cells 2020; 9:E1184. [PMID: 32397538 PMCID: PMC7290522 DOI: 10.3390/cells9051184] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 04/29/2020] [Accepted: 05/07/2020] [Indexed: 12/14/2022] Open
Abstract
In all eukaryotic cells, intracellular organization and spatial separation of incompatible biochemical processes is established by individual cellular subcompartments in form of membrane-bound organelles. Virtually all of these organelles are physically connected via membrane contact sites (MCS), allowing interorganellar communication and a functional integration of cellular processes. These MCS coordinate the exchange of diverse metabolites and serve as hubs for lipid synthesis and trafficking. While this of course indirectly impacts on a plethora of biological functions, including autophagy, accumulating evidence shows that MCS can also directly regulate autophagic processes. Here, we focus on the nexus between interorganellar contacts and autophagy in yeast and mammalian cells, highlighting similarities and differences. We discuss MCS connecting the ER to mitochondria or the plasma membrane, crucial for early steps of both selective and non-selective autophagy, the yeast-specific nuclear-vacuolar tethering system and its role in microautophagy, the emerging function of distinct autophagy-related proteins in organellar tethering as well as novel MCS transiently emanating from the growing phagophore and mature autophagosome.
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Affiliation(s)
- Verena Kohler
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 106 91 Stockholm, Sweden;
| | - Andreas Aufschnaiter
- Department of Biochemistry and Biophysics, Stockholm University, 106 91 Stockholm, Sweden;
| | - Sabrina Büttner
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 106 91 Stockholm, Sweden;
- Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria
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17
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Aufschnaiter A, Kohler V, Khalifa S, Abd El-Wahed A, Du M, El-Seedi H, Büttner S. Apitoxin and Its Components against Cancer, Neurodegeneration and Rheumatoid Arthritis: Limitations and Possibilities. Toxins (Basel) 2020; 12:toxins12020066. [PMID: 31973181 PMCID: PMC7076873 DOI: 10.3390/toxins12020066] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2019] [Revised: 01/18/2020] [Accepted: 01/19/2020] [Indexed: 02/03/2023] Open
Abstract
Natural products represent important sources for the discovery and design of novel drugs. Bee venom and its isolated components have been intensively studied with respect to their potential to counteract or ameliorate diverse human diseases. Despite extensive research and significant advances in recent years, multifactorial diseases such as cancer, rheumatoid arthritis and neurodegenerative diseases remain major healthcare issues at present. Although pure bee venom, apitoxin, is mostly described to mediate anti-inflammatory, anti-arthritic and neuroprotective effects, its primary component melittin may represent an anticancer therapeutic. In this review, we approach the possibilities and limitations of apitoxin and its components in the treatment of these multifactorial diseases. We further discuss the observed unspecific cytotoxicity of melittin that strongly restricts its therapeutic use and review interesting possibilities of a beneficial use by selectively targeting melittin to cancer cells.
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Affiliation(s)
- Andreas Aufschnaiter
- Department of Biochemistry and Biophysics, Stockholm University, Svante Arrheniusväg 16, 106 91 Stockholm, Sweden;
| | - Verena Kohler
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Svante Arrheniusväg 20C, 106 91 Stockholm, Sweden; (V.K.); (S.K.)
| | - Shaden Khalifa
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Svante Arrheniusväg 20C, 106 91 Stockholm, Sweden; (V.K.); (S.K.)
| | - Aida Abd El-Wahed
- Department of Bee Research, Plant Protection Research Institute, Agricultural Research Centre, 12627 Giza, Egypt;
- Pharmacognosy Group, Department of Medicinal Chemistry, Uppsala University, Biomedical Centre, Box 574, 751 23 Uppsala, Sweden
- Department of Chemistry, Faculty of Science, Menoufia University, 32512 Shebin El-Kom, Egypt
| | - Ming Du
- School of Food Science and Technology, National Engineering Research Center of Seafood, Dalian Polytechnic University, Dalian 116024, China;
| | - Hesham El-Seedi
- Pharmacognosy Group, Department of Medicinal Chemistry, Uppsala University, Biomedical Centre, Box 574, 751 23 Uppsala, Sweden
- Department of Chemistry, Faculty of Science, Menoufia University, 32512 Shebin El-Kom, Egypt
- International Research Center for Food nutrition and safety, Jiangsu University, Zhenjiang 212013, China
- Correspondence: (H.E.-S.); (S.B.)
| | - Sabrina Büttner
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Svante Arrheniusväg 20C, 106 91 Stockholm, Sweden; (V.K.); (S.K.)
- Institute of Molecular Biosciences, University of Graz, Humboldtstraße 50, 8010 Graz, Austria
- Correspondence: (H.E.-S.); (S.B.)
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18
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Stallinger A, Kohler V, Lammer A, Berger T, Probst I, Grohmann E, Keller W. TraF is an essential factor of the pIP501 type IV secretion system (T4SS) and exhibits structural homology with the T7SS protein EssB of Staphylococcus aureus. Acta Crystallogr A Found Adv 2019. [DOI: 10.1107/s2053273319094105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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19
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Kohler V, Goessweiner-Mohr N, Aufschnaiter A, Fercher C, Probst I, Pavkov-Keller T, Hunger K, Wolinski H, Büttner S, Grohmann E, Keller W. TraN: A novel repressor of an Enterococcus conjugative type IV secretion system. Nucleic Acids Res 2019; 46:9201-9219. [PMID: 30060171 PMCID: PMC6158623 DOI: 10.1093/nar/gky671] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Accepted: 07/18/2018] [Indexed: 11/19/2022] Open
Abstract
The dissemination of multi-resistant bacteria represents an enormous burden on modern healthcare. Plasmid-borne conjugative transfer is the most prevalent mechanism, requiring a type IV secretion system that enables bacteria to spread beneficial traits, such as resistance to last-line antibiotics, among different genera. Inc18 plasmids, like the Gram-positive broad host-range plasmid pIP501, are substantially involved in propagation of vancomycin resistance from Enterococci to methicillin-resistant strains of Staphylococcus aureus. Here, we identified the small cytosolic protein TraN as a repressor of the pIP501-encoded conjugative transfer system, since deletion of traN resulted in upregulation of transfer factors, leading to highly enhanced conjugative transfer. Furthermore, we report the complex structure of TraN with DNA and define the exact sequence of its binding motif. Targeting this protein–DNA interaction might represent a novel therapeutic approach against the spreading of antibiotic resistances.
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Affiliation(s)
- Verena Kohler
- Institute of Molecular Biosciences, University of Graz, Graz 8010, Austria
| | - Nikolaus Goessweiner-Mohr
- Institute of Molecular Biosciences, University of Graz, Graz 8010, Austria.,Institute of Biophysics, Johannes Kepler University, Linz 4020, Austria
| | | | - Christian Fercher
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, Qld 4072, Australia
| | - Ines Probst
- Division of Infectious Diseases, University Medical Center Freiburg, Freiburg 79106, Germany
| | - Tea Pavkov-Keller
- Institute of Molecular Biosciences, University of Graz, Graz 8010, Austria
| | - Kristin Hunger
- Institute of Molecular Biosciences, University of Graz, Graz 8010, Austria
| | - Heimo Wolinski
- Institute of Molecular Biosciences, University of Graz, Graz 8010, Austria
| | - Sabrina Büttner
- Institute of Molecular Biosciences, University of Graz, Graz 8010, Austria.,Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm 10691, Sweden
| | - Elisabeth Grohmann
- Division of Infectious Diseases, University Medical Center Freiburg, Freiburg 79106, Germany.,Life Sciences and Technology, Beuth University of Applied Sciences, Berlin 13353, Germany
| | - Walter Keller
- Institute of Molecular Biosciences, University of Graz, Graz 8010, Austria.,BioTechMed-Graz, Austria
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20
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Abstract
Type IV Secretion Systems (T4SSs) are membrane-spanning multiprotein complexes dedicated to protein secretion or conjugative DNA transport (conjugation systems) in bacteria. The prototype and best-characterized T4SS is that of the Gram-negative soil bacterium Agrobacterium tumefaciens. For Gram-positive bacteria, only conjugative T4SSs have been characterized in some biochemical, structural, and mechanistic details. These conjugation systems are predominantly encoded by self-transmissible plasmids but are also increasingly detected on integrative and conjugative elements (ICEs) and transposons. Here, we report regulatory details of conjugation systems from Enterococcus model plasmids pIP501 and pCF10, Bacillus plasmid pLS1, Clostridium plasmid pCW3, and staphylococcal plasmid pSK41. In addition, regulation of conjugative processes of ICEs (ICEBs1, ICESt1, ICESt3) by master regulators belonging to diverse repressor families will be discussed. A special focus of this review lies on the comparison of regulatory mechanisms executed by proteins belonging to the RRNPP family. These regulators share a common fold and govern several essential bacterial processes, including conjugative transfer.
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Affiliation(s)
- Verena Kohler
- Institute of Molecular Biosciences, BioTechMed Graz, University of Graz, Graz, Austria
| | - Walter Keller
- Institute of Molecular Biosciences, BioTechMed Graz, University of Graz, Graz, Austria
| | - Elisabeth Grohmann
- Life Sciences and Technology, Beuth University of Applied Sciences Berlin, Berlin, Germany
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21
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Keller W, Kohler V, Goessweiner-Mohr N, Aufschnaiter A, Fercher C, Probst I, Pavkov-Keller T, Hunger K, Wolinskiv H. Crystal structure of TraN, a regulator of conjugative DNA transfer, in complex with its cognate DNA binding site. Acta Crystallogr A Found Adv 2018. [DOI: 10.1107/s2053273318094755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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22
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Kohler V, Keller W, Grohmann E. Enterococcus adhesin PrgB facilitates type IV secretion by condensation of extracellular DNA. Mol Microbiol 2018; 109:263-267. [PMID: 29873122 DOI: 10.1111/mmi.13994] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/24/2018] [Indexed: 12/15/2022]
Abstract
Conjugative type IV secretion systems (T4SSs) are multi-protein complexes in Gram-negative and Gram-positive (G+) bacteria, responsible for spreading antibiotic resistances and virulence factors among different species. Compared to Gram-negative bacteria, which establish close contacts for conjugative transfer via sex pili, G+ T4SSs are suggested to employ surface adhesins instead. One example is pCF10, an enterococcal conjugative sex-pheromone responsive plasmid with a narrow host range, thus disseminating genetic information only among closely related species. This MicroCommentary is dedicated to the crystal structure of the pCF10-encoded adhesion domain of PrgB presented by Schmitt et al. The authors show in their work that this adhesion domain is responsible for biofilm formation, tight binding and condensation of extracellular DNA (eDNA) and conjugative transfer of pCF10. A sophisticated two-step mechanism for highly efficient conjugative transfer is postulated, including the formation of PrgB-mediated long-range intercellular contacts by binding and establishment of shorter-range contacts via condensation of eDNA. PrgB binding to lipoteichoic acid on the recipient cell surface stabilizes junctions between the mating partners. The major findings by Schmitt et al. will be brought into a broader context and potential medical applications targeting eDNA as essential component in biofilm formation and conjugation will be discussed.
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Affiliation(s)
- Verena Kohler
- Institute of Molecular Biosciences, BioTechMed, University of Graz, Graz, Austria
| | - Walter Keller
- Institute of Molecular Biosciences, BioTechMed, University of Graz, Graz, Austria
| | - Elisabeth Grohmann
- Life Sciences and Technology, Beuth University of Applied Sciences, Berlin, Germany
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23
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Aufschnaiter A, Kohler V, Walter C, Tosal-Castano S, Habernig L, Wolinski H, Keller W, Vögtle FN, Büttner S. The Enzymatic Core of the Parkinson's Disease-Associated Protein LRRK2 Impairs Mitochondrial Biogenesis in Aging Yeast. Front Mol Neurosci 2018; 11:205. [PMID: 29977190 PMCID: PMC6021522 DOI: 10.3389/fnmol.2018.00205] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Accepted: 05/22/2018] [Indexed: 02/01/2023] Open
Abstract
Mitochondrial dysfunction is a prominent trait of cellular decline during aging and intimately linked to neuronal degeneration during Parkinson's disease (PD). Various proteins associated with PD have been shown to differentially impact mitochondrial dynamics, quality control and function, including the leucine-rich repeat kinase 2 (LRRK2). Here, we demonstrate that high levels of the enzymatic core of human LRRK2, harboring GTPase as well as kinase activity, decreases mitochondrial mass via an impairment of mitochondrial biogenesis in aging yeast. We link mitochondrial depletion to a global downregulation of mitochondria-related gene transcripts and show that this catalytic core of LRRK2 localizes to mitochondria and selectively compromises respiratory chain complex IV formation. With progressing cellular age, this culminates in dissipation of mitochondrial transmembrane potential, decreased respiratory capacity, ATP depletion and generation of reactive oxygen species. Ultimately, the collapse of the mitochondrial network results in cell death. A point mutation in LRRK2 that increases the intrinsic GTPase activity diminishes mitochondrial impairment and consequently provides cytoprotection. In sum, we report that a downregulation of mitochondrial biogenesis rather than excessive degradation of mitochondria underlies the reduction of mitochondrial abundance induced by the enzymatic core of LRRK2 in aging yeast cells. Thus, our data provide a novel perspective for deciphering the causative mechanisms of LRRK2-associated PD pathology.
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Affiliation(s)
| | - Verena Kohler
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Corvin Walter
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Sergi Tosal-Castano
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Lukas Habernig
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Heimo Wolinski
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Walter Keller
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - F.-Nora Vögtle
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Sabrina Büttner
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
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24
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Kohler V, Vaishampayan A, Grohmann E. Broad-host-range Inc18 plasmids: Occurrence, spread and transfer mechanisms. Plasmid 2018; 99:11-21. [PMID: 29932966 DOI: 10.1016/j.plasmid.2018.06.001] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 06/17/2018] [Accepted: 06/18/2018] [Indexed: 11/18/2022]
Abstract
Conjugative plasmid transfer is one of the major mechanisms responsible for the spread of antibiotic resistance and virulence genes. The incompatibility (Inc) 18 group of plasmids is a family of plasmids replicating by the theta-mechanism, whose members have been detected frequently in enterococci and streptococci. Inc18 plasmids encode a variety of antibiotic resistances, including resistance to vancomycin, chloramphenicol and the macrolide-lincosamide-streptogramine (MLS) group of antibiotics. These plasmids comprising insertions of Tn1546 were demonstrated to be responsible for the transfer of vancomycin resistance encoded by the vanA gene from vancomycin resistant enterococci (VRE) to methicillin resistant Staphylococcus aureus (MRSA). Thereby vancomycin resistant S. aureus (VRSA) were generated, which are serious multi-resistant pathogens challenging the health care system. Inc18 plasmids are widespread in the clinic and frequently have been detected in the environment, especially in domestic animals and wastewater. pIP501 is one of the best-characterized conjugative Inc18 plasmids. It was originally isolated from a clinical Streptococcus agalactiae strain and is, due to its small size and simplicity, a model to study conjugative plasmid transfer in Gram-positive bacteria. Here, we report on the occurrence and spread of Inc18-type plasmids in the clinic and in different environments as well as on the exchange of the plasmids among them. In addition, we discuss molecular details on the transfer mechanism of Inc18 plasmids and its regulation, as exemplified by the model plasmid pIP501. We finish with an outlook on promising approaches on how to reduce the emerging spread of antibiotic resistances.
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Affiliation(s)
- Verena Kohler
- Institute of Molecular Biosciences, University of Graz, A-8010 Graz, Austria
| | - Ankita Vaishampayan
- Life Sciences and Technology, Beuth University of Applied Sciences Berlin, D-13347 Berlin, Germany
| | - Elisabeth Grohmann
- Life Sciences and Technology, Beuth University of Applied Sciences Berlin, D-13347 Berlin, Germany.
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25
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Aufschnaiter A, Habernig L, Kohler V, Diessl J, Carmona-Gutierrez D, Eisenberg T, Keller W, Büttner S. The Coordinated Action of Calcineurin and Cathepsin D Protects Against α-Synuclein Toxicity. Front Mol Neurosci 2017; 10:207. [PMID: 28713240 PMCID: PMC5491553 DOI: 10.3389/fnmol.2017.00207] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Accepted: 06/12/2017] [Indexed: 11/24/2022] Open
Abstract
The degeneration of dopaminergic neurons during Parkinson’s disease (PD) is intimately linked to malfunction of α-synuclein (αSyn), the main component of the proteinaceous intracellular inclusions characteristic for this pathology. The cytotoxicity of αSyn has been attributed to disturbances in several biological processes conserved from yeast to humans, including Ca2+ homeostasis, general lysosomal function and autophagy. However, the precise sequence of events that eventually results in cell death remains unclear. Here, we establish a connection between the major lysosomal protease cathepsin D (CatD) and the Ca2+/calmodulin-dependent phosphatase calcineurin. In a yeast model for PD, high levels of human αSyn triggered cytosolic acidification and reduced vacuolar hydrolytic capacity, finally leading to cell death. This could be counteracted by overexpression of yeast CatD (Pep4), which re-installed pH homeostasis and vacuolar proteolytic function, decreased αSyn oligomers and aggregates, and provided cytoprotection. Interestingly, these beneficial effects of Pep4 were independent of autophagy. Instead, they required functional calcineurin signaling, since deletion of calcineurin strongly reduced both the proteolytic activity of endogenous Pep4 and the cytoprotective capacity of overexpressed Pep4. Calcineurin contributed to proper endosomal targeting of Pep4 to the vacuole and the recycling of the Pep4 sorting receptor Pep1 from prevacuolar compartments back to the trans-Golgi network. Altogether, we demonstrate that stimulation of this novel calcineurin-Pep4 axis reduces αSyn cytotoxicity.
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Affiliation(s)
| | - Lukas Habernig
- Institute of Molecular Biosciences, University of GrazGraz, Austria.,Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm UniversityStockholm, Sweden
| | - Verena Kohler
- Institute of Molecular Biosciences, University of GrazGraz, Austria
| | - Jutta Diessl
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm UniversityStockholm, Sweden
| | | | - Tobias Eisenberg
- Institute of Molecular Biosciences, University of GrazGraz, Austria
| | - Walter Keller
- Institute of Molecular Biosciences, University of GrazGraz, Austria
| | - Sabrina Büttner
- Institute of Molecular Biosciences, University of GrazGraz, Austria.,Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm UniversityStockholm, Sweden
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26
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Aufschnaiter A, Kohler V, Diessl J, Peselj C, Carmona-Gutierrez D, Keller W, Büttner S. Mitochondrial lipids in neurodegeneration. Cell Tissue Res 2017; 367:125-140. [PMID: 27449929 PMCID: PMC5203858 DOI: 10.1007/s00441-016-2463-1] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2016] [Accepted: 06/24/2016] [Indexed: 01/10/2023]
Abstract
Mitochondrial dysfunction is a common feature of many neurodegenerative diseases, including proteinopathies such as Alzheimer's or Parkinson's disease, which are characterized by the deposition of aggregated proteins in the form of insoluble fibrils or plaques. The distinct molecular processes that eventually result in mitochondrial dysfunction during neurodegeneration are well studied but still not fully understood. However, defects in mitochondrial fission and fusion, mitophagy, oxidative phosphorylation and mitochondrial bioenergetics have been linked to cellular demise. These processes are influenced by the lipid environment within mitochondrial membranes as, besides membrane structure and curvature, recruitment and activity of different proteins also largely depend on the respective lipid composition. Hence, the interaction of neurotoxic proteins with certain lipids and the modification of lipid composition in different cell compartments, in particular mitochondria, decisively impact cell death associated with neurodegeneration. Here, we discuss the relevance of mitochondrial lipids in the pathological alterations that result in neuronal demise, focussing on proteinopathies.
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Affiliation(s)
- Andreas Aufschnaiter
- Institute of Molecular Biosciences, University of Graz, Humboldtstraße 50, 8010, Graz, Austria
| | - Verena Kohler
- Institute of Molecular Biosciences, University of Graz, Humboldtstraße 50, 8010, Graz, Austria
| | - Jutta Diessl
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Svante Arrheniusväg 20C, 106 91, Stockholm, Sweden
| | - Carlotta Peselj
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Svante Arrheniusväg 20C, 106 91, Stockholm, Sweden
| | - Didac Carmona-Gutierrez
- Institute of Molecular Biosciences, University of Graz, Humboldtstraße 50, 8010, Graz, Austria
| | - Walter Keller
- Institute of Molecular Biosciences, University of Graz, Humboldtstraße 50, 8010, Graz, Austria
| | - Sabrina Büttner
- Institute of Molecular Biosciences, University of Graz, Humboldtstraße 50, 8010, Graz, Austria.
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Svante Arrheniusväg 20C, 106 91, Stockholm, Sweden.
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27
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Abstract
Cellular homeostasis requires a tightly controlled balance between protein synthesis, folding and degradation. Especially long-lived, post-mitotic cells such as neurons depend on an efficient proteostasis system to maintain cellular health over decades. Thus, a functional decline of processes contributing to protein degradation such as autophagy and general lysosomal proteolytic capacity is connected to several age-associated neurodegenerative disorders, including Parkinson's, Alzheimer's and Huntington's diseases. These so called proteinopathies are characterized by the accumulation and misfolding of distinct proteins, subsequently driving cellular demise. We recently linked efficient lysosomal protein breakdown via the protease cathepsin D to the Ca2+/calmodulin-dependent phosphatase calcineurin. In a yeast model for Parkinson's disease, functional calcineurin was required for proper trafficking of cathepsin D to the lysosome and for recycling of its endosomal sorting receptor to allow further rounds of shuttling. Here, we discuss these findings in relation to present knowledge about the involvement of cathepsin D in proteinopathies in general and a possible connection between this protease, calcineurin signalling and endosomal sorting in particular. As dysregulation of Ca2+ homeostasis as well as lysosomal impairment is connected to a plethora of neurodegenerative disorders, this novel interplay might very well impact pathologies beyond Parkinson's disease.
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Affiliation(s)
- Andreas Aufschnaiter
- Institute of Molecular Biosciences, University of Graz, Humboldtstraße 50, 8010 Graz, Austria
| | - Verena Kohler
- Institute of Molecular Biosciences, University of Graz, Humboldtstraße 50, 8010 Graz, Austria
| | - Sabrina Büttner
- Institute of Molecular Biosciences, University of Graz, Humboldtstraße 50, 8010 Graz, Austria; Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Svante Arrheniusväg 20C, 106 91 Stockholm, Sweden
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Fercher C, Probst I, Kohler V, Goessweiner-Mohr N, Arends K, Grohmann E, Zangger K, Meyer NH, Keller W. VirB8-like protein TraH is crucial for DNA transfer in Enterococcus faecalis. Sci Rep 2016; 6:24643. [PMID: 27103580 PMCID: PMC4840375 DOI: 10.1038/srep24643] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2015] [Accepted: 04/04/2016] [Indexed: 12/02/2022] Open
Abstract
Untreatable bacterial infections caused by a perpetual increase of antibiotic resistant strains represent a serious threat to human healthcare in the 21(st) century. Conjugative DNA transfer is the most important mechanism for antibiotic resistance and virulence gene dissemination among bacteria and is mediated by a protein complex, known as type IV secretion system (T4SS). The core of the T4SS is a multiprotein complex that spans the bacterial envelope as a channel for macromolecular secretion. We report the NMR structure and functional characterization of the transfer protein TraH encoded by the conjugative Gram-positive broad-host range plasmid pIP501. The structure exhibits a striking similarity to VirB8 proteins of Gram-negative secretion systems where they play an essential role in the scaffold of the secretion machinery. Considering TraM as the first VirB8-like protein discovered in pIP501, TraH represents the second protein affiliated with this family in the respective transfer operon. A markerless traH deletion in pIP501 resulted in a total loss of transfer in Enterococcus faecalis as compared with the pIP501 wild type (wt) plasmid, demonstrating that TraH is essential for pIP501 mediated conjugation. Moreover, oligomerization state and topology of TraH in the native membrane were determined providing insights in molecular organization of a Gram-positive T4SS.
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Affiliation(s)
- Christian Fercher
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, Austria
| | - Ines Probst
- Division of Infectious Diseases, University Medical Center Freiburg, Germany
- Faculty of Biology, Microbiology, Albert-Ludwigs-University Freiburg, Germany
| | - Verena Kohler
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, Austria
| | - Nikolaus Goessweiner-Mohr
- Center for Structural System Biology (CSSB), University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany
- Deutsches Elektronen-Synchrotron (DESY), Hamburg, Germany
- Institute of Molecular Biotechnology (IMBA), Austrian Academy of Sciences, Vienna, Austria
- Research Institute of Molecular Pathology (IMP), Vienna, Austria
| | | | - Elisabeth Grohmann
- Division of Infectious Diseases, University Medical Center Freiburg, Germany
- Beuth University of Applied Sciences, Berlin, Germany
| | - Klaus Zangger
- Institute of Chemistry, University of Graz, Graz, Austria
| | - N. Helge Meyer
- Department of General and Visceral Surgery, University of Oldenburg, Germany
| | - Walter Keller
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, Austria
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29
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Abstract
A case of the adamantinom of the fibula has been reported. The tumor was resected six years ago. The yearly follow-up showed no sign of a relapse or metastases.
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Affiliation(s)
- H J Patzak
- Unfallchirurgische Klinik, Zentrums für Chirurgie, Justus-Liebig-Universität Giessen
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Southon MJ, Harris A, Kohler V, Mullock SJ, Wallach ER. Laser probe microanalysis: performance assessment and applications. SURF INTERFACE ANAL 1986. [DOI: 10.1002/sia.740090113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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