1
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Lebeda D, Fierenz A, Werfel L, Rosin-Arbesfeld R, Hofhuis J, Thoms S. Systematic and quantitative analysis of stop codon readthrough in Rett syndrome nonsense mutations. J Mol Med (Berl) 2024; 102:641-653. [PMID: 38430393 PMCID: PMC11055764 DOI: 10.1007/s00109-024-02436-6] [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: 10/13/2023] [Revised: 01/16/2024] [Accepted: 02/20/2024] [Indexed: 03/03/2024]
Abstract
Rett syndrome (RTT) is a neurodevelopmental disorder resulting from genetic mutations in the methyl CpG binding protein 2 (MeCP2) gene. Specifically, around 35% of RTT patients harbor premature termination codons (PTCs) within the MeCP2 gene due to nonsense mutations. A promising therapeutic avenue for these individuals involves the use of aminoglycosides, which stimulate translational readthrough (TR) by causing stop codons to be interpreted as sense codons. However, the effectiveness of this treatment depends on several factors, including the type of stop codon and the surrounding nucleotides, collectively referred to as the stop codon context (SCC). Here, we develop a high-content reporter system to precisely measure TR efficiency at different SCCs, assess the recovery of the full-length MeCP2 protein, and evaluate its subcellular localization. We have conducted a comprehensive investigation into the intricate relationship between SCC characteristics and TR induction, examining a total of 14 pathogenic MeCP2 nonsense mutations with the aim to advance the prospects of personalized therapy for individuals with RTT. Our results demonstrate that TR induction can successfully restore full-length MeCP2 protein, albeit to varying degrees, contingent upon the SCC and the specific position of the PTC within the MeCP2 mRNA. TR induction can lead to the re-establishment of nuclear localization of MeCP2, indicating the potential restoration of protein functionality. In summary, our findings underscore the significance of SCC-specific approaches in the development of tailored therapies for RTT. By unraveling the relationship between SCC and TR therapy, we pave the way for personalized, individualized treatment strategies that hold promise for improving the lives of individuals affected by this debilitating neurodevelopmental disorder. KEY MESSAGES: The efficiency of readthrough induction at MeCP2 premature termination codons strongly depends on the stop codon context. The position of the premature termination codon on the transcript influences the readthrough inducibility. A new high-content dual reporter assay facilitates the measurement and prediction of readthrough efficiency of specific nucleotide stop contexts. Readthrough induction results in the recovery of full-length MeCP2 and its re-localization to the nucleus. MeCP2 requires only one of its annotated nuclear localization signals.
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Affiliation(s)
- Dennis Lebeda
- Department for Biochemistry and Molecular Medicine, Medical School EWL, Bielefeld University, Bielefeld, Germany
| | - Adrian Fierenz
- Department of Child and Adolescent Health, University Medical Center Göttingen, Göttingen, Germany
| | - Lina Werfel
- Department of Child and Adolescent Health, University Medical Center Göttingen, Göttingen, Germany
- Present Address: Department of Pediatric Kidney, Liver and Metabolic Diseases, Hannover Medical School, Hannover, Germany
| | - Rina Rosin-Arbesfeld
- Department of Clinical Microbiology and Immunology, Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Julia Hofhuis
- Department for Biochemistry and Molecular Medicine, Medical School EWL, Bielefeld University, Bielefeld, Germany
| | - Sven Thoms
- Department for Biochemistry and Molecular Medicine, Medical School EWL, Bielefeld University, Bielefeld, Germany.
- Department of Child and Adolescent Health, University Medical Center Göttingen, Göttingen, Germany.
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2
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Plessner M, Thiele L, Hofhuis J, Thoms S. Tissue-specific roles of peroxisomes revealed by expression meta-analysis. Biol Direct 2024; 19:14. [PMID: 38365851 PMCID: PMC10873952 DOI: 10.1186/s13062-024-00458-1] [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: 09/14/2023] [Accepted: 01/30/2024] [Indexed: 02/18/2024] Open
Abstract
Peroxisomes are primarily studied in the brain, kidney, and liver due to the conspicuous tissue-specific pathology of peroxisomal biogenesis disorders. In contrast, little is known about the role of peroxisomes in other tissues such as the heart. In this meta-analysis, we explore mitochondrial and peroxisomal gene expression on RNA and protein levels in the brain, heart, kidney, and liver, focusing on lipid metabolism. Further, we evaluate a potential developmental and heart region-dependent specificity of our gene set. We find marginal expression of the enzymes for peroxisomal fatty acid oxidation in cardiac tissue in comparison to the liver or cardiac mitochondrial β-oxidation. However, the expression of peroxisome biogenesis proteins in the heart is similar to other tissues despite low levels of peroxisomal fatty acid oxidation. Strikingly, peroxisomal targeting signal type 2-containing factors and plasmalogen biosynthesis appear to play a fundamental role in explaining the essential protective and supporting functions of cardiac peroxisomes.
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Affiliation(s)
- Matthias Plessner
- Department of Biochemistry and Molecular Medicine, Medical School OWL, Bielefeld University, Bielefeld, Germany
| | - Leonie Thiele
- Department of Biochemistry and Molecular Medicine, Medical School OWL, Bielefeld University, Bielefeld, Germany
| | - Julia Hofhuis
- Department of Biochemistry and Molecular Medicine, Medical School OWL, Bielefeld University, Bielefeld, Germany
| | - Sven Thoms
- Department of Biochemistry and Molecular Medicine, Medical School OWL, Bielefeld University, Bielefeld, Germany.
- Department of Child and Adolescent Health, University Medical Center, Göttingen, Germany.
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3
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Wittenstein A, Caspi M, Rippin I, Elroy-Stein O, Eldar-Finkelman H, Thoms S, Rosin-Arbesfeld R. Correction: Nonsense mutation suppression is enhanced by targeting different stages of the protein synthesis process. PLoS Biol 2024; 22:e3002524. [PMID: 38354369 PMCID: PMC10866621 DOI: 10.1371/journal.pbio.3002524] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2024] Open
Abstract
[This corrects the article DOI: 10.1371/journal.pbio.3002355.].
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4
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Wittenstein A, Caspi M, Rippin I, Elroy-Stein O, Eldar-Finkelman H, Thoms S, Rosin-Arbesfeld R. Nonsense mutation suppression is enhanced by targeting different stages of the protein synthesis process. PLoS Biol 2023; 21:e3002355. [PMID: 37943958 PMCID: PMC10684085 DOI: 10.1371/journal.pbio.3002355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 11/28/2023] [Accepted: 09/29/2023] [Indexed: 11/12/2023] Open
Abstract
The introduction of premature termination codons (PTCs), as a result of splicing defects, insertions, deletions, or point mutations (also termed nonsense mutations), lead to numerous genetic diseases, ranging from rare neuro-metabolic disorders to relatively common inheritable cancer syndromes and muscular dystrophies. Over the years, a large number of studies have demonstrated that certain antibiotics and other synthetic molecules can act as PTC suppressors by inducing readthrough of nonsense mutations, thereby restoring the expression of full-length proteins. Unfortunately, most PTC readthrough-inducing agents are toxic, have limited effects, and cannot be used for therapeutic purposes. Thus, further efforts are required to improve the clinical outcome of nonsense mutation suppressors. Here, by focusing on enhancing readthrough of pathogenic nonsense mutations in the adenomatous polyposis coli (APC) tumor suppressor gene, we show that disturbing the protein translation initiation complex, as well as targeting other stages of the protein translation machinery, enhances both antibiotic and non-antibiotic-mediated readthrough of nonsense mutations. These findings strongly increase our understanding of the mechanisms involved in nonsense mutation readthrough and facilitate the development of novel therapeutic targets for nonsense suppression to restore protein expression from a large variety of disease-causing mutated transcripts.
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Affiliation(s)
- Amnon Wittenstein
- Department of Clinical Microbiology and Immunology, Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Michal Caspi
- Department of Clinical Microbiology and Immunology, Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Ido Rippin
- The Department of Human Molecular Genetics & Biochemistry School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Orna Elroy-Stein
- Shmunis School of Biomedicine and Cancer Research, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Hagit Eldar-Finkelman
- The Department of Human Molecular Genetics & Biochemistry School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Sven Thoms
- Biochemistry and Molecular Medicine, Medical School EWL, Bielefeld University, Bielefeld, Germany
| | - Rina Rosin-Arbesfeld
- Department of Clinical Microbiology and Immunology, Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
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5
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Sargsyan Y, Thoms S. Live-Cell Imaging of Peroxisomal Calcium Levels and Dynamics. Methods Mol Biol 2023; 2643:199-206. [PMID: 36952187 DOI: 10.1007/978-1-0716-3048-8_14] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/24/2023]
Abstract
Calcium (Ca2+) is an intracellular messenger that plays an essential role in a variety of cellular processes ranging from early embryonic events to muscle contraction and neuron excitability. Measurement of cytosolic, endoplasmic reticulum (ER), and mitochondrial Ca2+ has contributed immensely to our understanding of cellular physiology. Here we describe the measurement of peroxisomal Ca2+ using ratiometric Ca2+ sensors, enabling measurement of absolute Ca2+ concentration and its dynamics in living cells.
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Affiliation(s)
- Yelena Sargsyan
- Department of Child and Adolescent Health, University Medical Center, Göttingen, Germany
| | - Sven Thoms
- Department of Child and Adolescent Health, University Medical Center, Göttingen, Germany.
- Department for Biochemistry and Molecular Medicine, Medical School EWL, Bielefeld University, Bielefeld, Germany.
- German Center of Cardiovascular Research (DZHK), Partner site Göttingen, Göttingen, Germany.
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6
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Sargsyan Y, Kalinowski J, Thoms S. Calcium in peroxisomes: An essential messenger in an essential cell organelle. Front Cell Dev Biol 2022; 10:992235. [PMID: 36111338 PMCID: PMC9468670 DOI: 10.3389/fcell.2022.992235] [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] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Accepted: 08/10/2022] [Indexed: 11/17/2022] Open
Abstract
Calcium is a central signal transduction element in biology. Peroxisomes are essential cellular organelles, yet calcium handling in peroxisomes has been contentious. Recent advances show that peroxisomes are part of calcium homeostasis in cardiac myocytes and therefore may contribute to or even shape their calcium-dependent functionality. However, the mechanisms of calcium movement between peroxisomes and other cellular sites and their mediators remain elusive. Here, we review calcium handling in peroxisomes in concert with other organelles and summarize the most recent knowledge on peroxisomal involvement in calcium dynamics with a focus on mammalian cells.
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Affiliation(s)
- Yelena Sargsyan
- Department for Biochemistry and Molecular Medicine, Medical School EWL, Bielefeld University, Bielefeld, Germany
- Department of Child and Adolescent Health, University Medical Center, Göttingen, Germany
| | - Julia Kalinowski
- Department for Biochemistry and Molecular Medicine, Medical School EWL, Bielefeld University, Bielefeld, Germany
| | - Sven Thoms
- Department for Biochemistry and Molecular Medicine, Medical School EWL, Bielefeld University, Bielefeld, Germany
- Department of Child and Adolescent Health, University Medical Center, Göttingen, Germany
- German Center for Cardiovascular Research (DZHK), Partner Site Göttingen, Göttingen, Germany
- *Correspondence: Sven Thoms,
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7
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Nava E, Hartmann B, Boxheimer L, Capone Mori A, Nuoffer JM, Sargsyan Y, Thoms S, Rosewich H, Boltshauser E. How to Detect Isolated PEX10-Related Cerebellar Ataxia? Neuropediatrics 2022; 53:159-166. [PMID: 35038753 DOI: 10.1055/s-0041-1741383] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
A 4-year-old boy presented with subacute onset of cerebellar ataxia. Neuroimaging revealed cerebellar atrophy. Metabolic screening tests aiming to detect potentially treatable ataxias showed an increased value (fourfold upper limit of normal) for phytanic acid and elevated very-long-chain fatty acid (VLCFA) ratios (C24:0/C22:0 and C26:0/C22:0), while absolute concentrations of VLCFA were normal. Genetic analysis identified biallelic variants in PEX10. Immunohistochemistry confirmed pathogenicity in the patients' cultured fibroblasts demonstrating peroxisomal mosaicism with a general catalase import deficiency as well as conspicuous peroxisome morphology as an expression of impaired peroxisomal function. We describe for the first time an elongated peroxisome morphology in a patient with PEX10-related cerebellar ataxia.A literature search yielded 14 similar patients from nine families with PEX10-related cerebellar ataxia, most of them presenting their first symptoms between 3 and 8 years of age. In 11/14 patients, the first and main symptom was cerebellar ataxia; in three patients, it was sensorineural hearing impairment. Finally, all 14 patients developed ataxia. Polyneuropathy (9/14) and cognitive impairment (9/14) were common associated findings. In 12/13 patients brain MRI showed cerebellar atrophy. Phytanic acid was elevated in 8/12 patients, while absolute concentrations of VLCFA levels were in normal limits in several patients. VLCFA ratios (C24:0/C22:0 and/or C26:0/C22:0), though, were elevated in 11/11 cases. We suggest including measurement of phytanic acid and VLCFA ratios in metabolic screening tests in unexplained autosomal recessive ataxias with cerebellar atrophy, especially when there is an early onset and symptoms are mild.
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Affiliation(s)
- Esmeralda Nava
- Department of Pediatric Neurology, Cantonal Hospital Aarau, Aarau, Switzerland
| | - Britta Hartmann
- Department of Medical Genetics, Cantonal Hospital Aarau, Institute of Laboratory Medicine, Aarau, Switzerland
| | - Larissa Boxheimer
- Department of Neuroradiology, Cantonal Hospital Aarau, Aarau, Switzerland
| | - Andrea Capone Mori
- Department of Pediatric Neurology, Cantonal Hospital Aarau, Aarau, Switzerland
| | - Jean-Marc Nuoffer
- University Institute of Clinical Chemistry, Bern University Hospital, Bern, Switzerland.,University Children's Hospital Pediatric Endocrinology, Diabetology and Metabolism, Bern, Switzerland
| | - Yelena Sargsyan
- Department of Pediatrics and Adolescent Medicine, University Medical Center Göttingen, Göttingen, Germany
| | - Sven Thoms
- Department of Pediatrics and Adolescent Medicine, University Medical Center Göttingen, Göttingen, Germany.,Department of Biochemistry and Molecular Medicine, Medical School, Bielefeld University, Bielefeld, Germany
| | - Hendrik Rosewich
- Department of Pediatrics and Adolescent Medicine, University Medical Center Göttingen, Göttingen, Germany
| | - Eugen Boltshauser
- Department of Pediatric Neurology (emeritus), University Children's Hospital Zürich, Zürich, Switzerland
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8
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Oleksiievets N, Sargsyan Y, Thiele JC, Mougios N, Sograte-Idrissi S, Nevskyi O, Gregor I, Opazo F, Thoms S, Enderlein J, Tsukanov R. Fluorescence lifetime DNA-PAINT for multiplexed super-resolution imaging of cells. Commun Biol 2022; 5:38. [PMID: 35017652 PMCID: PMC8752799 DOI: 10.1038/s42003-021-02976-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [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: 05/25/2021] [Accepted: 12/08/2021] [Indexed: 11/08/2022] Open
Abstract
DNA point accumulation for imaging in nanoscale topography (DNA-PAINT) is a powerful super-resolution technique highly suitable for multi-target (multiplexing) bio-imaging. However, multiplexed imaging of cells is still challenging due to the dense and sticky environment inside a cell. Here, we combine fluorescence lifetime imaging microscopy (FLIM) with DNA-PAINT and use the lifetime information as a multiplexing parameter for targets identification. In contrast to Exchange-PAINT, fluorescence lifetime PAINT (FL-PAINT) can image multiple targets simultaneously and does not require any fluid exchange, thus leaving the sample undisturbed and making the use of flow chambers/microfluidic systems unnecessary. We demonstrate the potential of FL-PAINT by simultaneous imaging of up to three targets in a cell using both wide-field FLIM and 3D time-resolved confocal laser scanning microscopy (CLSM). FL-PAINT can be readily combined with other existing techniques of multiplexed imaging and is therefore a perfect candidate for high-throughput multi-target bio-imaging.
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Affiliation(s)
- Nazar Oleksiievets
- III. Institute of Physics - Biophysics, Georg August University, 37077, Göttingen, Germany
| | - Yelena Sargsyan
- Department of Child and Adolescent Health, University Medical Center Göttingen, 37073, Göttingen, Germany
| | - Jan Christoph Thiele
- III. Institute of Physics - Biophysics, Georg August University, 37077, Göttingen, Germany
| | - Nikolaos Mougios
- Institute of Neuro- and Sensory Physiology, University Medical Center Göttingen, 37073, Göttingen, Germany
- Center for Biostructural Imaging of Neurodegeneration (BIN), University Medical Center Göttingen, 37075, Göttingen, Germany
| | - Shama Sograte-Idrissi
- Institute of Neuro- and Sensory Physiology, University Medical Center Göttingen, 37073, Göttingen, Germany
- Center for Biostructural Imaging of Neurodegeneration (BIN), University Medical Center Göttingen, 37075, Göttingen, Germany
| | - Oleksii Nevskyi
- III. Institute of Physics - Biophysics, Georg August University, 37077, Göttingen, Germany
| | - Ingo Gregor
- III. Institute of Physics - Biophysics, Georg August University, 37077, Göttingen, Germany
| | - Felipe Opazo
- Institute of Neuro- and Sensory Physiology, University Medical Center Göttingen, 37073, Göttingen, Germany
- Center for Biostructural Imaging of Neurodegeneration (BIN), University Medical Center Göttingen, 37075, Göttingen, Germany
- NanoTag Biotechnologies GmbH, 37079, Göttingen, Germany
| | - Sven Thoms
- Department of Child and Adolescent Health, University Medical Center Göttingen, 37073, Göttingen, Germany
- Biochemistry and Molecular Medicine, Medical School, Bielefeld University, 33615, Bielefeld, Germany
| | - Jörg Enderlein
- III. Institute of Physics - Biophysics, Georg August University, 37077, Göttingen, Germany.
- Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), Georg August University, Göttingen, Germany.
| | - Roman Tsukanov
- III. Institute of Physics - Biophysics, Georg August University, 37077, Göttingen, Germany.
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9
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Sargsyan Y, Bickmeyer U, Gibhardt CS, Streckfuss-Bömeke K, Bogeski I, Thoms S. Peroxisomes contribute to intracellular calcium dynamics in cardiomyocytes and non-excitable cells. Life Sci Alliance 2021; 4:4/9/e202000987. [PMID: 34330788 PMCID: PMC8326789 DOI: 10.26508/lsa.202000987] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [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: 12/11/2020] [Revised: 07/09/2021] [Accepted: 07/12/2021] [Indexed: 11/24/2022] Open
Abstract
Peroxisomes communicate with other cellular compartments by transfer of various metabolites. However, whether peroxisomes are sites for calcium handling and exchange has remained contentious. Here we generated sensors for assessment of peroxisomal calcium and applied them for single cell-based calcium imaging in HeLa cells and cardiomyocytes. We found that peroxisomes in HeLa cells take up calcium upon depletion of intracellular calcium stores and upon calcium influx across the plasma membrane. Furthermore, we show that peroxisomes of neonatal rat cardiomyocytes and human induced pluripotent stem cell-derived cardiomyocytes can take up calcium. Our results indicate that peroxisomal and cytosolic calcium signals are tightly interconnected both in HeLa cells and in cardiomyocytes. Cardiac peroxisomes take up calcium on beat-to-beat basis. Hence, peroxisomes may play an important role in shaping cellular calcium dynamics of cardiomyocytes.
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Affiliation(s)
- Yelena Sargsyan
- Department of Child and Adolescent Health, University Medical Center, Göttingen, Germany
| | - Uta Bickmeyer
- Department of Child and Adolescent Health, University Medical Center, Göttingen, Germany
| | - Christine S Gibhardt
- Molecular Physiology, Institute of Cardiovascular Physiology, University Medical Center, Göttingen, Germany
| | - Katrin Streckfuss-Bömeke
- Clinic for Cardiology and Pneumology, University Medical Center, Göttingen, Germany.,Institute of Pharmacology and Toxicology, Würzburg University, Würzburg, Germany.,German Center of Cardiovascular Research (DZHK), Partner Site Göttingen, Germany
| | - Ivan Bogeski
- Molecular Physiology, Institute of Cardiovascular Physiology, University Medical Center, Göttingen, Germany
| | - Sven Thoms
- Department of Child and Adolescent Health, University Medical Center, Göttingen, Germany .,Department of Biochemistry and Molecular Medicine, Medical School, Bielefeld University, Bielefeld, Germany.,German Center of Cardiovascular Research (DZHK), Partner Site Göttingen, Germany
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10
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Schilff M, Sargsyan Y, Hofhuis J, Thoms S. Stop Codon Context-Specific Induction of Translational Readthrough. Biomolecules 2021; 11:biom11071006. [PMID: 34356630 PMCID: PMC8301745 DOI: 10.3390/biom11071006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 06/28/2021] [Accepted: 07/01/2021] [Indexed: 12/11/2022] Open
Abstract
Premature termination codon (PTC) mutations account for approximately 10% of pathogenic variants in monogenic diseases. Stimulation of translational readthrough, also known as stop codon suppression, using translational readthrough-inducing drugs (TRIDs) may serve as a possible therapeutic strategy for the treatment of genetic PTC diseases. One important parameter governing readthrough is the stop codon context (SCC)-the stop codon itself and the nucleotides in the vicinity of the stop codon on the mRNA. However, the quantitative influence of the SCC on treatment outcome and on appropriate drug concentrations are largely unknown. Here, we analyze the readthrough-stimulatory effect of various readthrough-inducing drugs on the SCCs of five common premature termination codon mutations of PEX5 in a sensitive dual reporter system. Mutations in PEX5, encoding the peroxisomal targeting signal 1 receptor, can cause peroxisomal biogenesis disorders of the Zellweger spectrum. We show that the stop context has a strong influence on the levels of readthrough stimulation and impacts the choice of the most effective drug and its concentration. These results highlight potential advantages and the personalized medicine nature of an SCC-based strategy in the therapy of rare diseases.
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Affiliation(s)
- Mirco Schilff
- Department of Child and Adolescent Health, University Medical Center, 37075 Göttingen, Germany; (M.S.); (Y.S.); (J.H.)
| | - Yelena Sargsyan
- Department of Child and Adolescent Health, University Medical Center, 37075 Göttingen, Germany; (M.S.); (Y.S.); (J.H.)
| | - Julia Hofhuis
- Department of Child and Adolescent Health, University Medical Center, 37075 Göttingen, Germany; (M.S.); (Y.S.); (J.H.)
- Department of Biochemistry and Molecular Medicine, Medical School, Bielefeld University, 33615 Bielefeld, Germany
| | - Sven Thoms
- Department of Child and Adolescent Health, University Medical Center, 37075 Göttingen, Germany; (M.S.); (Y.S.); (J.H.)
- Department of Biochemistry and Molecular Medicine, Medical School, Bielefeld University, 33615 Bielefeld, Germany
- Correspondence: ; Tel.: +49-521-106-86502
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11
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Hofhuis J, Bersch K, Wagner S, Molina C, Fakuade FE, Iyer LM, Streckfuss-Bömeke K, Toischer K, Zelarayán LC, Voigt N, Nikolaev VO, Maier LS, Klinge L, Thoms S. Dysferlin links excitation-contraction coupling to structure and maintenance of the cardiac transverse-axial tubule system. Europace 2021; 22:1119-1131. [PMID: 32572487 DOI: 10.1093/europace/euaa093] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Revised: 01/27/2020] [Accepted: 04/03/2020] [Indexed: 12/24/2022] Open
Abstract
AIMS The multi-C2 domain protein dysferlin localizes to the T-Tubule system of skeletal and heart muscles. In skeletal muscle, dysferlin is known to play a role in membrane repair and in T-tubule biogenesis and maintenance. Dysferlin deficiency manifests as muscular dystrophy of proximal and distal muscles. Cardiomyopathies have been also reported, and some dysferlinopathy mouse models develop cardiac dysfunction under stress. Generally, the role and functional relevance of dysferlin in the heart is not clear. The aim of this study was to analyse the effect of dysferlin deficiency on the transverse-axial tubule system (TATS) structure and on Ca2+ homeostasis in the heart. METHODS AND RESULTS We studied dysferlin localization in rat and mouse cardiomyocytes by immunofluorescence microscopy. In dysferlin-deficient ventricular mouse cardiomyocytes, we analysed the TATS by live staining and assessed Ca2+ handling by patch-clamp experiments and measurement of Ca2+ transients and Ca2+ sparks. We found increasing co-localization of dysferlin with the L-type Ca2+-channel during TATS development and show that dysferlin deficiency leads to pathological loss of transversal and increase in longitudinal elements (axialization). We detected reduced L-type Ca2+-current (ICa,L) in cardiomyocytes from dysferlin-deficient mice and increased frequency of spontaneous sarcoplasmic reticulum Ca2+ release events resulting in pro-arrhythmic contractions. Moreover, cardiomyocytes from dysferlin-deficient mice showed an impaired response to β-adrenergic receptor stimulation. CONCLUSIONS Dysferlin is required for TATS biogenesis and maintenance in the heart by controlling the ratio of transversal and axial membrane elements. Absence of dysferlin leads to defects in Ca2+ homeostasis which may contribute to contractile heart dysfunction in dysferlinopathy patients.
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Affiliation(s)
- Julia Hofhuis
- Department of Child and Adolescent Health, University Medical Center Göttingen, Robert-Koch-Straße 40, 37075 Göttingen, Germany.,DZHK (German Center for Cardiovascular Research), Partner Sites Göttingen and Hamburg, Germany
| | - Kristina Bersch
- Department of Child and Adolescent Health, University Medical Center Göttingen, Robert-Koch-Straße 40, 37075 Göttingen, Germany
| | - Stefan Wagner
- Department of Cardiology, University Hospital Regensburg, Regensburg, Germany
| | - Cristina Molina
- DZHK (German Center for Cardiovascular Research), Partner Sites Göttingen and Hamburg, Germany.,Institute of Pharmacology and Toxicology, University Medical Center Göttingen, Göttingen, Germany.,Institute for Experimental Cardiology, University Medical Center Hamburg, Hamburg, Germany
| | - Funsho E Fakuade
- Institute of Pharmacology and Toxicology, University Medical Center Göttingen, Göttingen, Germany
| | - Lavanya M Iyer
- DZHK (German Center for Cardiovascular Research), Partner Sites Göttingen and Hamburg, Germany.,Institute of Pharmacology and Toxicology, University Medical Center Göttingen, Göttingen, Germany.,Computational and Systems Biology, Genome Institute of Singapore, Singapore, Singapore
| | - Katrin Streckfuss-Bömeke
- DZHK (German Center for Cardiovascular Research), Partner Sites Göttingen and Hamburg, Germany.,Department of Cardiology and Pneumonology, University Medical Center Göttingen, Göttingen, Germany
| | - Karl Toischer
- DZHK (German Center for Cardiovascular Research), Partner Sites Göttingen and Hamburg, Germany.,Department of Cardiology and Pneumonology, University Medical Center Göttingen, Göttingen, Germany
| | - Laura C Zelarayán
- DZHK (German Center for Cardiovascular Research), Partner Sites Göttingen and Hamburg, Germany.,Institute of Pharmacology and Toxicology, University Medical Center Göttingen, Göttingen, Germany
| | - Niels Voigt
- DZHK (German Center for Cardiovascular Research), Partner Sites Göttingen and Hamburg, Germany.,Institute of Pharmacology and Toxicology, University Medical Center Göttingen, Göttingen, Germany
| | - Viacheslav O Nikolaev
- DZHK (German Center for Cardiovascular Research), Partner Sites Göttingen and Hamburg, Germany.,Institute of Pharmacology and Toxicology, University Medical Center Göttingen, Göttingen, Germany.,Institute for Experimental Cardiology, University Medical Center Hamburg, Hamburg, Germany
| | - Lars S Maier
- Department of Cardiology, University Hospital Regensburg, Regensburg, Germany
| | - Lars Klinge
- Department of Child and Adolescent Health, University Medical Center Göttingen, Robert-Koch-Straße 40, 37075 Göttingen, Germany.,Kinderarztpraxis Göttingen, Göttingen, Germany
| | - Sven Thoms
- Department of Child and Adolescent Health, University Medical Center Göttingen, Robert-Koch-Straße 40, 37075 Göttingen, Germany.,DZHK (German Center for Cardiovascular Research), Partner Sites Göttingen and Hamburg, Germany
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12
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Soliman K, Göttfert F, Rosewich H, Thoms S, Gärtner J. Super-resolution imaging reveals the sub-diffraction phenotype of Zellweger Syndrome ghosts and wild-type peroxisomes. Sci Rep 2018; 8:7809. [PMID: 29773809 PMCID: PMC5958128 DOI: 10.1038/s41598-018-24119-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Accepted: 03/22/2018] [Indexed: 11/12/2022] Open
Abstract
Peroxisomes are ubiquitous cell organelles involved in many metabolic and signaling functions. Their assembly requires peroxins, encoded by PEX genes. Mutations in PEX genes are the cause of Zellweger Syndrome spectrum (ZSS), a heterogeneous group of peroxisomal biogenesis disorders (PBD). The size and morphological features of peroxisomes are below the diffraction limit of light, which makes them attractive for super-resolution imaging. We applied Stimulated Emission Depletion (STED) microscopy to study the morphology of human peroxisomes and peroxisomal protein localization in human controls and ZSS patients. We defined the peroxisome morphology in healthy skin fibroblasts and the sub-diffraction phenotype of residual peroxisomal structures (‘ghosts’) in ZSS patients that revealed a relation between mutation severity and clinical phenotype. Further, we investigated the 70 kDa peroxisomal membrane protein (PMP70) abundance in relationship to the ZSS sub-diffraction phenotype. This work improves the morphological definition of peroxisomes. It expands current knowledge about peroxisome biogenesis and ZSS pathoethiology to the sub-diffraction phenotype including key peroxins and the characteristics of ghost peroxisomes.
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Affiliation(s)
- Kareem Soliman
- Department of Pediatrics and Adolescent Medicine, University Medical Center Göttingen, Georg August University Göttingen, Robert-Koch-Strasse 40, 37075, Göttingen, Germany.,Optical Nanoscopy, Laser-Laboratorium Göttingen e.V., 37077, Göttingen, Germany
| | - Fabian Göttfert
- Department of NanoBiophotonics, Max Planck Institute for Biophysical Chemistry, Am Faßberg 11, 37077, Göttingen, Germany
| | - Hendrik Rosewich
- Department of Pediatrics and Adolescent Medicine, University Medical Center Göttingen, Georg August University Göttingen, Robert-Koch-Strasse 40, 37075, Göttingen, Germany
| | - Sven Thoms
- Department of Pediatrics and Adolescent Medicine, University Medical Center Göttingen, Georg August University Göttingen, Robert-Koch-Strasse 40, 37075, Göttingen, Germany.
| | - Jutta Gärtner
- Department of Pediatrics and Adolescent Medicine, University Medical Center Göttingen, Georg August University Göttingen, Robert-Koch-Strasse 40, 37075, Göttingen, Germany
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13
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Abstract
In a compartmentalized cell, correct protein localization is crucial for function of virtually all cellular processes. From the cytoplasm as a starting point, proteins are imported into organelles by specific targeting signals. Many proteins, however, act in more than one cellular compartment. In this chapter, we discuss mechanisms by which proteins can be targeted to multiple organelles with a focus on a novel gene regulatory mechanism, functional translational readthrough, that permits multiple targeting of proteins to the peroxisome and other organelles. In mammals, lactate and malate dehydrogenase are the best-characterized enzymes whose targeting is controlled by functional translational readthrough.
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Affiliation(s)
- Kristina Bersch
- Department of Child and Adolescent Health, University Medical Center Göttingen, University of Göttingen, Robert-Koch-Str. 40, 37075, Göttingen, Germany
| | - Ignacio Lobos Matthei
- Department of Child and Adolescent Health, University Medical Center Göttingen, University of Göttingen, Robert-Koch-Str. 40, 37075, Göttingen, Germany
| | - Sven Thoms
- Department of Child and Adolescent Health, University Medical Center Göttingen, University of Göttingen, Robert-Koch-Str. 40, 37075, Göttingen, Germany.
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14
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Hofhuis J, Schueren F, Nötzel C, Lingner T, Gärtner J, Jahn O, Thoms S. The functional readthrough extension of malate dehydrogenase reveals a modification of the genetic code. Open Biol 2017; 6:rsob.160246. [PMID: 27881739 PMCID: PMC5133446 DOI: 10.1098/rsob.160246] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Accepted: 10/21/2016] [Indexed: 01/19/2023] Open
Abstract
Translational readthrough gives rise to C-terminally extended proteins, thereby providing the cell with new protein isoforms. These may have different properties from the parental proteins if the extensions contain functional domains. While for most genes amino acid incorporation at the stop codon is far lower than 0.1%, about 4% of malate dehydrogenase (MDH1) is physiologically extended by translational readthrough and the actual ratio of MDH1x (extended protein) to ‘normal' MDH1 is dependent on the cell type. In human cells, arginine and tryptophan are co-encoded by the MDH1x UGA stop codon. Readthrough is controlled by the 7-nucleotide high-readthrough stop codon context without contribution of the subsequent 50 nucleotides encoding the extension. All vertebrate MDH1x is directed to peroxisomes via a hidden peroxisomal targeting signal (PTS) in the readthrough extension, which is more highly conserved than the extension of lactate dehydrogenase B. The hidden PTS of non-mammalian MDH1x evolved to be more efficient than the PTS of mammalian MDH1x. These results provide insight into the genetic and functional co-evolution of these dually localized dehydrogenases.
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Affiliation(s)
- Julia Hofhuis
- Department of Pediatrics and Adolescent Medicine, University Medical Center Göttingen, University of Göttingen, 37075 Göttingen, Germany
| | - Fabian Schueren
- Department of Pediatrics and Adolescent Medicine, University Medical Center Göttingen, University of Göttingen, 37075 Göttingen, Germany
| | - Christopher Nötzel
- Department of Pediatrics and Adolescent Medicine, University Medical Center Göttingen, University of Göttingen, 37075 Göttingen, Germany
| | - Thomas Lingner
- Microarray and Deep Sequencing Core Facility, University Medical Center Göttingen, University of Göttingen, 37077 Göttingen, Germany
| | - Jutta Gärtner
- Department of Pediatrics and Adolescent Medicine, University Medical Center Göttingen, University of Göttingen, 37075 Göttingen, Germany
| | - Olaf Jahn
- Proteomics Group, Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany
| | - Sven Thoms
- Department of Pediatrics and Adolescent Medicine, University Medical Center Göttingen, University of Göttingen, 37075 Göttingen, Germany
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15
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Lipstein N, Verhoeven-Duif NM, Michelassi FE, Calloway N, van Hasselt PM, Pienkowska K, van Haaften G, van Haelst MM, van Empelen R, Cuppen I, van Teeseling HC, Evelein AMV, Vorstman JA, Thoms S, Jahn O, Duran KJ, Monroe GR, Ryan TA, Taschenberger H, Dittman JS, Rhee JS, Visser G, Jans JJ, Brose N. Synaptic UNC13A protein variant causes increased neurotransmission and dyskinetic movement disorder. J Clin Invest 2017; 127:1005-1018. [PMID: 28192369 DOI: 10.1172/jci90259] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Accepted: 12/15/2016] [Indexed: 12/13/2022] Open
Abstract
Munc13 proteins are essential regulators of neurotransmitter release at nerve cell synapses. They mediate the priming step that renders synaptic vesicles fusion-competent, and their genetic elimination causes a complete block of synaptic transmission. Here we have described a patient displaying a disorder characterized by a dyskinetic movement disorder, developmental delay, and autism. Using whole-exome sequencing, we have shown that this condition is associated with a rare, de novo Pro814Leu variant in the major human Munc13 paralog UNC13A (also known as Munc13-1). Electrophysiological studies in murine neuronal cultures and functional analyses in Caenorhabditis elegans revealed that the UNC13A variant causes a distinct dominant gain of function that is characterized by increased fusion propensity of synaptic vesicles, which leads to increased initial synaptic vesicle release probability and abnormal short-term synaptic plasticity. Our study underscores the critical importance of fine-tuned presynaptic control in normal brain function. Further, it adds the neuronal Munc13 proteins and the synaptic vesicle priming process that they control to the known etiological mechanisms of psychiatric and neurological synaptopathies.
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16
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Hofhuis J, Bersch K, Büssenschütt R, Drzymalski M, Liebetanz D, Nikolaev VO, Wagner S, Maier LS, Gärtner J, Klinge L, Thoms S. Dysferlin mediates membrane tubulation and links T-tubule biogenesis to muscular dystrophy. J Cell Sci 2017; 130:841-852. [PMID: 28104817 DOI: 10.1242/jcs.198861] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Accepted: 12/28/2016] [Indexed: 12/30/2022] Open
Abstract
The multi-C2 domain protein dysferlin localizes to the plasma membrane and the T-tubule system in skeletal muscle; however, its physiological mode of action is unknown. Mutations in the DYSF gene lead to autosomal recessive limb-girdle muscular dystrophy type 2B and Miyoshi myopathy. Here, we show that dysferlin has membrane tubulating capacity and that it shapes the T-tubule system. Dysferlin tubulates liposomes, generates a T-tubule-like membrane system in non-muscle cells, and links the recruitment of phosphatidylinositol 4,5-bisphosphate to the biogenesis of the T-tubule system. Pathogenic mutant forms interfere with all of these functions, indicating that muscular wasting and dystrophy are caused by the dysferlin mutants' inability to form a functional T-tubule membrane system.
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Affiliation(s)
- Julia Hofhuis
- Department of Child and Adolescent Health, University Medical Centre Göttingen, Göttingen 37075, Germany
| | - Kristina Bersch
- Department of Child and Adolescent Health, University Medical Centre Göttingen, Göttingen 37075, Germany
| | - Ronja Büssenschütt
- Department of Child and Adolescent Health, University Medical Centre Göttingen, Göttingen 37075, Germany
| | - Marzena Drzymalski
- Department of Child and Adolescent Health, University Medical Centre Göttingen, Göttingen 37075, Germany
| | - David Liebetanz
- Department of Clinical Neurophysiology, University Medical Centre Göttingen, Göttingen 37075, Germany
| | - Viacheslav O Nikolaev
- Department of Cardiology and Pneumology, Heart Research Centre Göttingen, Göttingen 37075, Germany
| | - Stefan Wagner
- Department of Internal Medicine II, University Medical Centre Regensburg, Regensburg 93042, Germany
| | - Lars S Maier
- Department of Internal Medicine II, University Medical Centre Regensburg, Regensburg 93042, Germany
| | - Jutta Gärtner
- Department of Child and Adolescent Health, University Medical Centre Göttingen, Göttingen 37075, Germany
| | - Lars Klinge
- Department of Child and Adolescent Health, University Medical Centre Göttingen, Göttingen 37075, Germany
| | - Sven Thoms
- Department of Child and Adolescent Health, University Medical Centre Göttingen, Göttingen 37075, Germany
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17
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Yofe I, Soliman K, Chuartzman SG, Morgan B, Weill U, Yifrach E, Dick TP, Cooper SJ, Ejsing CS, Schuldiner M, Zalckvar E, Thoms S. Pex35 is a regulator of peroxisome abundance. J Cell Sci 2017; 130:791-804. [PMID: 28049721 DOI: 10.1242/jcs.187914] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Accepted: 11/24/2016] [Indexed: 12/12/2022] Open
Abstract
Peroxisomes are cellular organelles with vital functions in lipid, amino acid and redox metabolism. The cellular formation and dynamics of peroxisomes are governed by PEX genes; however, the regulation of peroxisome abundance is still poorly understood. Here, we use a high-content microscopy screen in Saccharomyces cerevisiae to identify new regulators of peroxisome size and abundance. Our screen led to the identification of a previously uncharacterized gene, which we term PEX35, which affects peroxisome abundance. PEX35 encodes a peroxisomal membrane protein, a remote homolog to several curvature-generating human proteins. We systematically characterized the genetic and physical interactome as well as the metabolome of mutants in PEX35, and we found that Pex35 functionally interacts with the vesicle-budding-inducer Arf1. Our results highlight the functional interaction between peroxisomes and the secretory pathway.
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Affiliation(s)
- Ido Yofe
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Kareem Soliman
- Department of Child and Adolescent Health, University Medical Center, Göttingen 37075, Germany
| | - Silvia G Chuartzman
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Bruce Morgan
- Department of Cellular Biochemistry, University of Kaiserslautern, Kaiserslautern 67653, Germany.,Division of Redox Regulation, ZMBH-DKFZ Alliance, German Cancer Research Center (DKFZ), Heidelberg 69121, Germany
| | - Uri Weill
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Eden Yifrach
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Tobias P Dick
- Division of Redox Regulation, ZMBH-DKFZ Alliance, German Cancer Research Center (DKFZ), Heidelberg 69121, Germany
| | - Sara J Cooper
- HudsonAlpha Institute for Biotechnology, Huntsville, AL 35806, USA
| | - Christer S Ejsing
- Department of Biochemistry and Molecular Biology, VILLUM Center for Bioanalytical Sciences, University of Southern Denmark, Odense 5230, Denmark
| | - Maya Schuldiner
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Einat Zalckvar
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Sven Thoms
- Department of Child and Adolescent Health, University Medical Center, Göttingen 37075, Germany
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18
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Buentzel J, Thoms S. The Use of Glycosylation Tags as Reporters for Protein Entry into the Endoplasmic Reticulum in Yeast and Mammalian Cells. Methods Mol Biol 2017; 1595:221-232. [PMID: 28409466 DOI: 10.1007/978-1-4939-6937-1_21] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
N-glycosylation is a process occurring in the Endoplasmic Reticulum (ER) in nearly every organism. Proteins containing a glycosylation site are quickly glycosylated by oligosaccharyltransferases once the glycosylation site is exposed to the ER lumen. The oligosaccharide tree is then modified and proteins are targeted to specific organelles or subcompartments. For a long time peroxisomal membrane proteins (PMP) were thought to be targeted directly to the peroxisome. However, in the course of recent years, several PMPs were found to be targeted via the ER. Glycosylation increases the molecular weight of a protein, which is easily detected by Western blotting. Glycosylation tags like the opsin tag are therefore useful tools in the study of ER entry of peroxisomal proteins.
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Affiliation(s)
- Judith Buentzel
- Department of Pediatrics and Adolescent Health, University Medical Center, University of Goettingen, Robert-Koch-Str. 40, 37075, Goettingen, Germany
| | - Sven Thoms
- Department of Pediatrics and Adolescent Health, University Medical Center, University of Goettingen, Robert-Koch-Str. 40, 37075, Goettingen, Germany.
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19
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Abstract
Translational readthrough, the decoding of stop codons as sense codons, leads to C-terminal extension of proteins which may lead to the formation of protein isoforms with distinct properties from the original protein. Two proteins have recently been identified that are targeted to the peroxisome via hidden peroxisomal targeting signals in their readthrough extensions. This noninduced basal translational readthrough can be distinguished from pharmacological induction of readthrough by aminoglycosides or other small molecules, which can be used for the treatment of diseases caused by premature stop (termination) codons (PTCs). Readthrough of both, natural stop codons and PTCs, can be quantified in cell culture using reporter systems. In the present article, we describe two dual reporter systems, based on combined fluorescence/luminescence measurement and flow cytometric fluorescence measurement, respectively. Further, we provide a protocol for a fast and efficient cloning procedure of reporter constructs. The dual reporter systems described here help to analyze the peroxisome-specific isoforms of readthrough enzymes as well as potential readthrough therapeutics.
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Affiliation(s)
- Julia Hofhuis
- Department of Pediatrics and Adolescent Health, University Medical Center G&ttingen, University of G&ttingen, Robert-Koch-Strasse 40, D-37075, G&ttingen, Germany
| | - Severin Dieterle
- Department of Pediatrics and Adolescent Health, University Medical Center G&ttingen, University of G&ttingen, Robert-Koch-Strasse 40, D-37075, G&ttingen, Germany
| | - Rosemol George
- Department of Pediatrics and Adolescent Health, University Medical Center G&ttingen, University of G&ttingen, Robert-Koch-Strasse 40, D-37075, G&ttingen, Germany
| | - Fabian Schueren
- Department of Pediatrics and Adolescent Health, University Medical Center G&ttingen, University of G&ttingen, Robert-Koch-Strasse 40, D-37075, G&ttingen, Germany
| | - Sven Thoms
- Department of Pediatrics and Adolescent Health, University Medical Center G&ttingen, University of G&ttingen, Robert-Koch-Strasse 40, D-37075, G&ttingen, Germany. &ttingen.de
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20
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Nötzel C, Lingner T, Klingenberg H, Thoms S. Identification of New Fungal Peroxisomal Matrix Proteins and Revision of the PTS1 Consensus. Traffic 2016; 17:1110-24. [PMID: 27392156 DOI: 10.1111/tra.12426] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Revised: 07/05/2016] [Accepted: 07/05/2016] [Indexed: 12/20/2022]
Abstract
The peroxisomal targeting signal type 1 (PTS1) is a seemingly simple peptide sequence at the C-terminal end of most peroxisomal matrix proteins. PTS1 can be described as a tripeptide with the consensus motif [S/A/C] [K/R/H] L. However, this description is neither necessary nor sufficient. It does not cover all cases of PTS1 proteins, and some proteins in accordance with this consensus do not target to the peroxisome. In order to find new PTS proteins in yeast and to arrive at a more complete description of the PTS1 consensus motif, we developed a machine learning approach that involves orthologue expansion of the set of known peroxisomal proteins. We performed a genome-wide in silico screen, characterised several PTS1-containing peptides and identified two new peroxisomal matrix proteins, which we named Pxp1 (Yel020c) and Pxp2 (Yjr111c). Based on these in silico and in vivo analyses, we revised the yeast PTS1 consensus which now includes all known PTS1 proteins.
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Affiliation(s)
- Christopher Nötzel
- Department of Child and Adolescent Health, University Medical Center, University of Göttingen, Göttingen, Germany.,Current address: Program in Biochemistry and Structural Biology, Cell and Developmental Biology, and Molecular Biology, Weill Cornell Graduate School of Medical Sciences, New York, NY, USA
| | - Thomas Lingner
- Department of Bioinformatics, Institute for Microbiology and Genetics, University of Göttingen, Göttingen, Germany.,Current address: Microarray and Deep Sequencing Core Facility, University Medical Center, University of Göttingen, Göttingen, Germany
| | - Heiner Klingenberg
- Department of Bioinformatics, Institute for Microbiology and Genetics, University of Göttingen, Göttingen, Germany
| | - Sven Thoms
- Department of Child and Adolescent Health, University Medical Center, University of Göttingen, Göttingen, Germany.
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21
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Abstract
Peroxisomes are capable of importing folded and oligomeric proteins. However, it is a matter of dispute whether oligomer import by peroxisomes is the exception or the rule. Here, I argue for a clear distinction between homo-oligomeric proteins that are essentially peroxisomal, and dually localized hetero-oligomers that access the peroxisome by piggyback import, localizing there in limited number, whereas the majority remain in the cytosol. Homo-oligomeric proteins comprise the majority of all peroxisomal matrix proteins. There is evidence that binding by Pex5 in the cytosol can regulate their oligomerization state before import. The hetero-oligomer group is made up of superoxide dismutase and lactate dehydrogenase. These proteins have evolved mechanisms that render import inefficient and retain the majority of proteins in the cytosol.
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Affiliation(s)
- Sven Thoms
- Department of Child and Adolescent Medicine, University Medical Center, University of Göttingen, Robert-Koch-Str. 40, 37075 Göttingen, Germany
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22
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Abstract
Translational readthrough (TR) has come into renewed focus because systems biology approaches have identified the first human genes undergoing functional translational readthrough (FTR). FTR creates functional extensions to proteins by continuing translation of the mRNA downstream of the stop codon. Here we review recent developments in TR research with a focus on the identification of FTR in humans and the systems biology methods that have spurred these discoveries.
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Affiliation(s)
- Fabian Schueren
- University Medical Center, Department of Child and Adolescent Health, University of Göttingen, Göttingen, Germany
| | - Sven Thoms
- University Medical Center, Department of Child and Adolescent Health, University of Göttingen, Göttingen, Germany
- * E-mail:
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23
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Taylor RJE, Childs DTD, Ivanov P, Stevens BJ, Babazadeh N, Crombie AJ, Ternent G, Thoms S, Zhou H, Hogg RA. Electronic control of coherence in a two-dimensional array of photonic crystal surface emitting lasers. Sci Rep 2015; 5:13203. [PMID: 26289621 PMCID: PMC4542471 DOI: 10.1038/srep13203] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [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: 04/07/2015] [Accepted: 07/14/2015] [Indexed: 11/15/2022] Open
Abstract
We demonstrate a semiconductor PCSEL array that uniquely combines an in-plane waveguide structure with nano-scale patterned PCSEL elements. This novel geometry allows two-dimensional electronically controllable coherent coupling of remote vertically emitting lasers. Mutual coherence of the PCSEL elements is verified through the demonstration of a two-dimensional Young’s Slits experiment. In addition to allowing the all-electronic control of the interference pattern, this type of device offers new routes to power and brightness scaling in semiconductor lasers, and opportunities for all-electronic beam steering.
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Affiliation(s)
- R J E Taylor
- Department of Electronic &Electrical Engineering, Centre for Nanoscience &Technology, North Campus, The University of Sheffield, Broad Lane, Sheffield, S3 7HQ, United Kingdom
| | - D T D Childs
- Department of Electronic &Electrical Engineering, Centre for Nanoscience &Technology, North Campus, The University of Sheffield, Broad Lane, Sheffield, S3 7HQ, United Kingdom
| | - P Ivanov
- Department of Electronic &Electrical Engineering, Centre for Nanoscience &Technology, North Campus, The University of Sheffield, Broad Lane, Sheffield, S3 7HQ, United Kingdom
| | - B J Stevens
- Department of Electronic &Electrical Engineering, Centre for Nanoscience &Technology, North Campus, The University of Sheffield, Broad Lane, Sheffield, S3 7HQ, United Kingdom
| | - N Babazadeh
- Department of Electronic &Electrical Engineering, Centre for Nanoscience &Technology, North Campus, The University of Sheffield, Broad Lane, Sheffield, S3 7HQ, United Kingdom
| | - A J Crombie
- Department of Electronic &Electrical Engineering, Centre for Nanoscience &Technology, North Campus, The University of Sheffield, Broad Lane, Sheffield, S3 7HQ, United Kingdom
| | - G Ternent
- James Watt Nanofabrication Centre, James Watt Building, University of Glasgow, University Avenue, Glasgow G12 8QQ
| | - S Thoms
- James Watt Nanofabrication Centre, James Watt Building, University of Glasgow, University Avenue, Glasgow G12 8QQ
| | - H Zhou
- James Watt Nanofabrication Centre, James Watt Building, University of Glasgow, University Avenue, Glasgow G12 8QQ
| | - R A Hogg
- Department of Electronic &Electrical Engineering, Centre for Nanoscience &Technology, North Campus, The University of Sheffield, Broad Lane, Sheffield, S3 7HQ, United Kingdom
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24
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Haas C, Zschüntzsch J, Thoms S, Schmidt J. Endoplasmic reticulum stress induced by inflammation in skeletal muscle cells is associated with protein accumulation and reduced by methylene blue: Implications for inclusion body myositis. J Neuroimmunol 2014. [DOI: 10.1016/j.jneuroim.2014.08.161] [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: 11/25/2022]
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25
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Hofhuis J, Thoms S, Klinge L. G.P.285. Neuromuscul Disord 2014. [DOI: 10.1016/j.nmd.2014.06.361] [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: 11/27/2022]
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26
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Schueren F, Lingner T, George R, Hofhuis J, Dickel C, Gärtner J, Thoms S. Peroxisomal lactate dehydrogenase is generated by translational readthrough in mammals. eLife 2014; 3:e03640. [PMID: 25247702 PMCID: PMC4359377 DOI: 10.7554/elife.03640] [Citation(s) in RCA: 127] [Impact Index Per Article: 12.7] [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: 06/09/2014] [Accepted: 09/22/2014] [Indexed: 01/24/2023] Open
Abstract
Translational readthrough gives rise to low abundance proteins with C-terminal extensions beyond the stop codon. To identify functional translational readthrough, we estimated the readthrough propensity (RTP) of all stop codon contexts of the human genome by a new regression model in silico, identified a nucleotide consensus motif for high RTP by using this model, and analyzed all readthrough extensions in silico with a new predictor for peroxisomal targeting signal type 1 (PTS1). Lactate dehydrogenase B (LDHB) showed the highest combined RTP and PTS1 probability. Experimentally we show that at least 1.6% of the total cellular LDHB is targeted to the peroxisome by a conserved hidden PTS1. The readthrough-extended lactate dehydrogenase subunit LDHBx can also co-import LDHA, the other LDH subunit, into peroxisomes. Peroxisomal LDH is conserved in mammals and likely contributes to redox equivalent regeneration in peroxisomes. DOI:http://dx.doi.org/10.7554/eLife.03640.001 Amino acids are the building blocks of proteins, and the order of the amino acids in a protein is determined by the order in which ‘codons’ appear in a messenger RNA molecule. Most codons represent a specific amino acid, but there are also three stop codons that are used to mark the end of a protein. When the cellular machinery that ‘translates’ the messenger RNA molecule into a protein encounters a stop codon, it stops and releases the completed protein. Sometimes, however, the stop codon is not interpreted as a stop signal, and the translation of the messenger RNA molecule continues until another stop codon is encountered. This process is known as readthrough. Some organisms, in particular viruses and fungi, use readthrough to produce a wider range of proteins than their genomes would otherwise allow. While readthrough also occurs in higher organisms such as mammals, it is not known if the resulting proteins perform extra functions that the original protein does not perform. A number of factors affect whether readthrough occurs when an mRNA template is being translated. For example, each of the three stop codons has a different likelihood of having its stop signal misinterpreted, and the mRNA sequence that surrounds the stop codon can also affect the likelihood of readthrough. Schueren et al. have developed a computational model that estimates how common this form of translational readthrough is in the human genome. The model was based on the identity of the stop codons themselves and the surrounding mRNA sequence. This model was then combined with another model that identifies proteins that are targeted to a structure inside a cell called the peroxisome, which is where a number of essential energy-releasing reactions take place. The combined model enabled Schueren et al. to identify proteins that both perform functions in the peroxisome and are likely to be formed by readthrough. The combined model suggested a protein that is a part of lactate dehydrogenase: an enzyme that speeds up chemical reactions that are important for the cell to produce energy. Low levels of lactate dehydrogenase had previously been found in the peroxisome, despite it apparently lacking a specific sequence of amino acids that proteins need to have to enter the peroxisome. However, Schueren et al. confirmed experimentally that readthrough does occur for the lactate dehydrogenase component identified by the model, revealing that it contains a ‘hidden’ peroxisome-targeting region. Furthermore, when more translational readthrough occurred, more lactate dehydrogenase was found in the peroxisomes. This unusual way that lactate dehydrogenase enters the peroxisome is an example of how the cell optimizes the used of the genetic information encoded in the genome and in messenger RNA. Translational readthrough always ensures that a certain proportion of lactate dehydrogenase will be brought to the peroxisome. The computational model developed here will be a valuable tool to identify other such proteins produced from genomes, including the human genome and those of other species. DOI:http://dx.doi.org/10.7554/eLife.03640.002
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Affiliation(s)
- Fabian Schueren
- Department of Pediatrics and Adolescent Medicine, University Medical Center, Georg-August-University Göttingen, Göttingen, Germany
| | - Thomas Lingner
- Department of Bioinformatics, Institute for Microbiology and Genetics, Georg-August-University Göttingen, Göttingen, Germany
| | - Rosemol George
- Department of Pediatrics and Adolescent Medicine, University Medical Center, Georg-August-University Göttingen, Göttingen, Germany
| | - Julia Hofhuis
- Department of Pediatrics and Adolescent Medicine, University Medical Center, Georg-August-University Göttingen, Göttingen, Germany
| | - Corinna Dickel
- Department of Pediatrics and Adolescent Medicine, University Medical Center, Georg-August-University Göttingen, Göttingen, Germany
| | - Jutta Gärtner
- Department of Pediatrics and Adolescent Medicine, University Medical Center, Georg-August-University Göttingen, Göttingen, Germany
| | - Sven Thoms
- Department of Pediatrics and Adolescent Medicine, University Medical Center, Georg-August-University Göttingen, Göttingen, Germany
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Kutschan B, Morawetz K, Thoms S. Dynamical mechanism of antifreeze proteins to prevent ice growth. Phys Rev E Stat Nonlin Soft Matter Phys 2014; 90:022711. [PMID: 25215762 DOI: 10.1103/physreve.90.022711] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Indexed: 06/03/2023]
Abstract
The fascinating ability of algae, insects, and fishes to survive at temperatures below normal freezing is realized by antifreeze proteins (AFPs). These are surface-active molecules and interact with the diffusive water-ice interface thus preventing complete solidification. We propose a dynamical mechanism on how these proteins inhibit the freezing of water. We apply a Ginzburg-Landau-type approach to describe the phase separation in the two-component system (ice, AFP). The free-energy density involves two fields: one for the ice phase with a low AFP concentration and one for liquid water with a high AFP concentration. The time evolution of the ice reveals microstructures resulting from phase separation in the presence of AFPs. We observed a faster clustering of pre-ice structure connected to a locking of grain size by the action of AFP, which is an essentially dynamical process. The adsorption of additional water molecules is inhibited and the further growth of ice grains stopped. The interfacial energy between ice and water is lowered allowing the AFPs to form smaller critical ice nuclei. Similar to a hysteresis in magnetic materials we observe a thermodynamic hysteresis leading to a nonlinear density dependence of the freezing point depression in agreement with the experiments.
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Affiliation(s)
- B Kutschan
- Münster University of Applied Science, Stegerwaldstrasse 39, 48565 Steinfurt, Germany
| | - K Morawetz
- Münster University of Applied Science, Stegerwaldstrasse 39, 48565 Steinfurt, Germany and International Institute of Physics (IIP), Federal University of Rio Grande do Norte, Av. Odilon Gomes de Lima 1722, 59078-400 Natal, Brazil and Max-Planck-Institute for the Physics of Complex Systems, 01187 Dresden, Germany
| | - S Thoms
- Alfred Wegener Institut, Am Handelshafen 12, D-27570 Bremerhaven, Germany
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Cohen Y, Klug YA, Dimitrov L, Erez Z, Chuartzman SG, Elinger D, Yofe I, Soliman K, Gärtner J, Thoms S, Schekman R, Elbaz-Alon Y, Zalckvar E, Schuldiner M. Peroxisomes are juxtaposed to strategic sites on mitochondria. Mol Biosyst 2014; 10:1742-8. [PMID: 24722918 DOI: 10.1039/c4mb00001c] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Peroxisomes are ubiquitous and dynamic organelles that house many important pathways of cellular metabolism. In recent years it has been demonstrated that mitochondria are tightly connected with peroxisomes and are defective in several peroxisomal diseases. Indeed, these two organelles share metabolic routes as well as resident proteins and, at least in mammals, are connected via a vesicular transport pathway. However the exact extent of cross-talk between peroxisomes and mitochondria remains unclear. Here we used a combination of high throughput genetic manipulations of yeast libraries alongside high content screens to systematically unravel proteins that affect the transport of peroxisomal proteins and peroxisome biogenesis. Follow up work on the effector proteins that were identified revealed that peroxisomes are not randomly distributed in cells but are rather localized to specific mitochondrial subdomains such as mitochondria-ER junctions and sites of acetyl-CoA synthesis. Our approach highlights the intricate geography of the cell and suggests an additional layer of organization as a possible way to enable efficient metabolism. Our findings pave the way for further studying the machinery aligning mitochondria and peroxisomes, the role of the juxtaposition, as well as its regulation during various metabolic conditions. More broadly, the approaches used here can be easily applied to study any organelle of choice, facilitating the discovery of new aspects in cell biology.
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Affiliation(s)
- Yifat Cohen
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel.
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Abstract
Among the human PEX genes associated with peroxisome biogenesis disorders, only the PEX11 family genes had not previously been associated with human disease. A new study identifies the first patient with a mutation in PEX11β. The patient presents with symptoms atypical for peroxisome biogenesis disorders. Peroxisomes in cells derived from this patient appear enlarged and undivided, complying with the role of PEX11 proteins in peroxisome proliferation and division. These new findings widen the spectrum of clinical and cellular phenotypes of diseases associated with defective peroxisome formation.
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Affiliation(s)
- S Thoms
- Department of Pediatrics and Pediatric Neurology, University Medical Center Göttingen, Georg August University Göttingen, Göttingen, Germany.
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Otzen M, Rucktäschel R, Thoms S, Emmrich K, Krikken AM, Erdmann R, van der Klei IJ. Pex19p contributes to peroxisome inheritance in the association of peroxisomes to Myo2p. Traffic 2012; 13:947-59. [PMID: 22486971 DOI: 10.1111/j.1600-0854.2012.01364.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2012] [Revised: 04/04/2012] [Accepted: 04/09/2012] [Indexed: 11/29/2022]
Abstract
During budding of yeast cells peroxisomes are distributed over mother cell and bud, a process that involves the myosin motor protein Myo2p and the peroxisomal membrane protein Inp2p. Here, we show that Pex19p, a peroxin implicated in targeting and complex formation of peroxisomal membrane proteins, also plays a role in peroxisome partitioning. Binding studies revealed that Pex19p interacts with the cargo-binding domain of Myo2p. We identified mutations in Myo2p that specifically reduced binding to Pex19p, but not to Inp2p. The interaction between Myo2p and Pex19p was also reduced by a mutation that blocked Pex19p farnesylation. Microscopy revealed that the Pex19p-Myo2p interaction is important for peroxisome inheritance, because mutations that affect this interaction hamper peroxisome inheritance in vivo. Together these data suggest that both Inp2p and Pex19p are required for proper association of peroxisomes to Myo2p.
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Affiliation(s)
- Marleen Otzen
- Molecular Cell Biology, Groningen Biomolecular Sciences and Biotechnology Institute-GBB, Kluyver Centre for Genomics of Industrial Fermentation, University of Groningen, Groningen, the Netherlands
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Quentin T, Steinmetz M, Poppe A, Thoms S. Metformin differentially activates ER stress signaling pathways without inducing apoptosis. J Cell Sci 2012. [DOI: 10.1242/jcs.108654] [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: 11/20/2022] Open
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Thoms S, Harms I, Kalies KU, Gärtner J. Peroxisome formation requires the endoplasmic reticulum channel protein Sec61. Traffic 2012; 13:599-609. [PMID: 22212716 DOI: 10.1111/j.1600-0854.2011.01324.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2011] [Revised: 12/21/2011] [Accepted: 12/23/2011] [Indexed: 12/21/2022]
Abstract
In peroxisome formation, models of near-autonomous peroxisome biogenesis with membrane protein integration directly from the cytosol into the peroxisomal membrane are in direct conflict with models whereby peroxisomes bud from the endoplasmic reticulum and receive their membrane proteins through a branch of the secretory pathway. We therefore reinvestigated the role of the Sec61 complex, the protein-conducting channel of the endoplasmic reticulum (ER) in peroxisome formation. We found that depletion or partial inactivation of Sec61 in yeast disables peroxisome formation. The ER entry of the early peroxisomal membrane protein Pex3 engineered with a glycosylation tag is reduced in sec61 mutant cells. Moreover, we were able to reconstitute Pex3 import into ER membranes in vitro, and we identified a variant of a signal anchor sequence for ER translocation at the Pex3 N-terminus. Our findings are consistent with a Sec61 requirement for peroxisome formation and a fundamental role of the ER in peroxisome biogenesis.
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Affiliation(s)
- Sven Thoms
- Department of Pediatrics and Pediatric Neurology, University Medical Center, Georg August University of Göttingen, 37075, Göttingen, Germany.
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Swayne TC, Zhou C, Boldogh IR, Charalel JK, McFaline-Figueroa JR, Thoms S, Yang C, Leung G, McInnes J, Erdmann R, Pon LA. Role for cER and Mmr1p in anchorage of mitochondria at sites of polarized surface growth in budding yeast. Curr Biol 2011; 21:1994-9. [PMID: 22119524 DOI: 10.1016/j.cub.2011.10.019] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2010] [Revised: 09/16/2011] [Accepted: 10/11/2011] [Indexed: 12/21/2022]
Abstract
Mitochondria accumulate at neuronal and immunological synapses and yeast bud tips and associate with the ER during phospholipid biosynthesis, calcium homeostasis, and mitochondrial fission. Here we show that mitochondria are associated with cortical ER (cER) sheets underlying the plasma membrane in the bud tip and confirm that a deletion in YPT11, which inhibits cER accumulation in the bud tip, also inhibits bud tip anchorage of mitochondria. Time-lapse imaging reveals that mitochondria are anchored at specific sites in the bud tip. Mmr1p, a member of the DSL1 family of tethering proteins, localizes to punctate structures on opposing surfaces of mitochondria and cER sheets underlying the bud tip and is recovered with isolated mitochondria and ER. Deletion of MMR1 impairs bud tip anchorage of mitochondria without affecting mitochondrial velocity or cER distribution. Deletion of the phosphatase PTC1 results in increased Mmr1p phosphorylation, mislocalization of Mmr1p, defects in association of Mmr1p with mitochondria and ER, and defects in bud tip anchorage of mitochondria. These findings indicate that Mmr1p contributes to mitochondrial inheritance as a mediator of anchorage of mitochondria to cER sheets in the yeast bud tip and that Ptc1p regulates Mmr1p phosphorylation, localization, and function.
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Affiliation(s)
- Theresa C Swayne
- Department of Pathology and Cell Biology, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA
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Quentin T, Steinmetz M, Poppe A, Thoms S. Metformin differentially activates ER stress signaling pathways without inducing apoptosis. Dis Model Mech 2011; 5:259-69. [PMID: 22107872 PMCID: PMC3291647 DOI: 10.1242/dmm.008110] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Endoplasmic reticulum stress signaling (ERSS) plays an important role in the pathogenesis of diabetes and heart disease. The latter is a common comorbidity of diabetes and worsens patient outcome. Results from clinical studies suggest beneficial effects of metformin – a widely used oral drug for the treatment of type 2 diabetes – on the heart of diabetic patients with heart failure. We therefore analyzed the effect of metformin on ERSS in primary rat cardiomyocytes. We found that metformin activates the PERK-ATF4 but not the ATF6 or IRE1-XBP1 branch in ERSS and leads to a strong upregulation of CHOP mRNA and protein. Surprisingly, long-term induction of CHOP by metformin is not accompanied by apoptosis even though CHOP is regarded to be a mediator of ER-stress-induced apoptosis. In conclusion, metformin induces distinct ER stress pathways in cardiomyocytes and our results indicate that CHOP is not necessarily a mediator of apoptosis. Metformin might exert its cardioprotective effect through selective activation of ERSS pathways in the cardiomyocyte.
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Affiliation(s)
- Thomas Quentin
- Department of Pediatric Cardiology and Pediatric Intensive Care Medicine, University of Göttingen, Göttingen, Germany.
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Thoms S, Grønborg S, Rabenau J, Ohlenbusch A, Rosewich H, Gärtner J. Characterization of two common 5' polymorphisms in PEX1 and correlation to survival in PEX1 peroxisome biogenesis disorder patients. BMC Med Genet 2011; 12:109. [PMID: 21846392 PMCID: PMC3167756 DOI: 10.1186/1471-2350-12-109] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/02/2011] [Accepted: 08/16/2011] [Indexed: 11/10/2022]
Abstract
Background Mutations in PEX1 are the most common primary cause of Zellweger syndrome. In addition to exonic mutations, deletions and splice site mutations two 5' polymorphisms at c.-137 and c.-53 with a potential influence on PEX1 protein levels have been described in the 5' untranslated region (UTR) of the PEX1 gene. Methods We used RACE and in silico promoter prediction analysis to study the 5' UTR of PEX1. We determined the distribution of PEX1 5' polymorphisms in a cohort of 30 Zellweger syndrome patients by standard DNA sequencing. 5' polymorphisms were analysed in relation to the two most common mutations in PEX1 and were incorporated into a novel genotype-phenotype analysis by correlation of three classes of PEX1 mutations with patient survival. Results We provide evidence that the polymorphism 137 bp upstream of the ATG codon is not part of the UTR, rendering it a promoter polymorphism. We show that the first, but not the second most common PEX1 mutation arose independently of a specific upstream polymorphic constellation. By genotype-phenotype analysis we identified patients with identical exonic mutation and identical 5' polymorphisms, but strongly differing survival. Conclusions Our study suggests that two different types of PEX1 5' polymorphisms have to be distinguished: a 5' UTR polymorphism at position c.-53 and a promoter polymorphism 137 bp upstream of the PEX1 start codon. Our results indicate that the exonic PEX1 mutation correlates with patient survival, but the two 5' polymorphisms analysed in this study do not have to be considered for diagnostic and/or prognostic purposes.
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Affiliation(s)
- Sven Thoms
- Department of Pediatrics and Pediatric Neurology, University Medical Center, University of Göttingen, Robert Koch Str, 40, 37099 Göttingen, Germany.
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Debelyy MO, Platta HW, Saffian D, Hensel A, Thoms S, Meyer HE, Warscheid B, Girzalsky W, Erdmann R. Ubp15p, a ubiquitin hydrolase associated with the peroxisomal export machinery. J Biol Chem 2011; 286:28223-34. [PMID: 21665945 DOI: 10.1074/jbc.m111.238600] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Peroxisomal matrix protein import is facilitated by cycling receptors shuttling between the cytosol and the peroxisomal membrane. One crucial step in this cycle is the ATP-dependent release of the receptors from the peroxisomal membrane. This step is facilitated by the peroxisomal AAA (ATPases associated with various cellular activities) proteins Pex1p and Pex6p with ubiquitination of the receptor being the main signal for its export. Here we report that the AAA complex contains dislocase as well as deubiquitinating activity. Ubp15p, a ubiquitin hydrolase, was identified as a novel constituent of the complex. Ubp15p partially localizes to peroxisomes and is capable of cleaving off ubiquitin moieties from the type I peroxisomal targeting sequence (PTS1) receptor Pex5p. Furthermore, Ubp15p-deficient cells are characterized by a stress-related PTS1 import defect. The results merge into a picture in which removal of ubiquitin from the PTS1 receptor Pex5p is a specific event and might represent a vital step in receptor recycling.
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Affiliation(s)
- Mykhaylo O Debelyy
- Abteilung für Systembiochemie, Medizinische Fakultät der Ruhr-Universität Bochum, Bochum, Germany
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Kaczmarek K, Studencka M, Meinhardt A, Wieczerzak K, Thoms S, Engel W, Grzmil P. Overexpression of peroxisomal testis-specific 1 protein induces germ cell apoptosis and leads to infertility in male mice. Mol Biol Cell 2011; 22:1766-79. [PMID: 21460186 PMCID: PMC3093327 DOI: 10.1091/mbc.e09-12-0993] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Peroxisomal testis-specific 1 gene (Pxt1) is the only male germ cell-specific gene that encodes a peroxisomal protein known to date. To elucidate the role of Pxt1 in spermatogenesis, we generated transgenic mice expressing a c-MYC-PXT1 fusion protein under the control of the PGK2 promoter. Overexpression of Pxt1 resulted in induction of male germ cells' apoptosis mainly in primary spermatocytes, finally leading to male infertility. This prompted us to analyze the proapoptotic character of mouse PXT1, which harbors a BH3-like domain in the N-terminal part. In different cell lines, the overexpression of PXT1 also resulted in a dramatic increase of apoptosis, whereas the deletion of the BH3-like domain significantly reduced cell death events, thereby confirming that the domain is functional and essential for the proapoptotic activity of PXT1. Moreover, we demonstrated that PXT1 interacts with apoptosis regulator BAT3, which, if overexpressed, can protect cells from the PXT1-induced apoptosis. The PXT1-BAT3 association leads to PXT1 relocation from the cytoplasm to the nucleus. In summary, we demonstrated that PXT1 induces apoptosis via the BH3-like domain and that this process is inhibited by BAT3.
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Affiliation(s)
- Karina Kaczmarek
- Institute of Human Genetics, Georg-August-University of Göttingen, 37073 Göttingen, Germany
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Thoms S, Grønborg S, Gärtner J. Organelle interplay in peroxisomal disorders. Trends Mol Med 2009; 15:293-302. [DOI: 10.1016/j.molmed.2009.05.002] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2009] [Revised: 05/07/2009] [Accepted: 05/07/2009] [Indexed: 11/17/2022]
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Henneke M, Diekmann S, Ohlenbusch A, Kaiser J, Engelbrecht V, Kohlschütter A, Krätzner R, Madruga-Garrido M, Mayer M, Opitz L, Rodriguez D, Rüschendorf F, Schumacher J, Thiele H, Thoms S, Steinfeld R, Nürnberg P, Gärtner J. RNASET2-deficient cystic leukoencephalopathy resembles congenital cytomegalovirus brain infection. Nat Genet 2009; 41:773-5. [DOI: 10.1038/ng.398] [Citation(s) in RCA: 111] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2009] [Accepted: 05/12/2009] [Indexed: 12/22/2022]
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Rucktäschel R, Thoms S, Sidorovitch V, Halbach A, Pechlivanis M, Volkmer R, Alexandrov K, Kuhlmann J, Rottensteiner H, Erdmann R. Farnesylation of pex19p is required for its structural integrity and function in peroxisome biogenesis. J Biol Chem 2009; 284:20885-96. [PMID: 19451657 DOI: 10.1074/jbc.m109.016584] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The conserved CaaX box peroxin Pex19p is known to be modified by farnesylation. The possible involvement of this lipid modification in peroxisome biogenesis, the degree to which Pex19p is farnesylated, and its molecular function are unknown or controversial. We resolve these issues by first showing that the complete pool of Pex19p is processed by farnesyltransferase in vivo and that this modification is independent of peroxisome induction or the Pex19p membrane anchor Pex3p. Furthermore, genomic mutations of PEX19 prove that farnesylation is essential for proper matrix protein import into peroxisomes, which is supposed to be caused indirectly by a defect in peroxisomal membrane protein (PMP) targeting or stability. This assumption is corroborated by the observation that mutants defective in Pex19p farnesylation are characterized by a significantly reduced steady-state concentration of prominent PMPs (Pex11p, Ant1p) but also of essential components of the peroxisomal import machinery, especially the RING peroxins, which were almost depleted from the importomer. In vivo and in vitro, PMP recognition is only efficient when Pex19p is farnesylated with affinities differing by a factor of 10 between the non-modified and wild-type forms of Pex19p. Farnesylation is likely to induce a conformational change in Pex19p. Thus, isoprenylation of Pex19p contributes to substrate membrane protein recognition for the topogenesis of PMPs, and our results highlight the importance of lipid modifications in protein-protein interactions.
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Affiliation(s)
- Robert Rucktäschel
- Department for Systems Biochemistry, Institute for Physiological Chemistry, University of Bochum, Universitätsstrasse 150, 44780 Bochum
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Stachon A, Aweimer A, Stachon T, Tannapfel A, Thoms S, Ubrig B, Köller M, Krieg M, Truss MC. Secretion of soluble VEGF receptor 2 by microvascular endothelial cells derived by human benign prostatic hyperplasia. Growth Factors 2009; 27:71-8. [PMID: 19199116 DOI: 10.1080/08977190802709619] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Vascular endothelial growth factor (VEGF) is one of the most potent mitogenic factors stimulating both prostate endothelial and prostate epithelial cells. Recently, some studies reported on the endothelial secretion of a soluble VEGF receptor 2 (sVEGFR-2) that modifies the free VEGF concentration by binding VEGF. For the first time in this study, we report on the secretion and the regulation of the secretion of sVEGFR-2 by microvascular endothelial cells derived from the tissue of human benign prostatic hyperplasia (HPEC). HPEC were isolated and cultured from fresh prostate tissue. The prostate epithelial cell line BPH-1 was cultured with the supernatant of the HPEC cell culture (fractioned by fast protein liquid chromatography) and the VEGF concentration was subsequently measured. HPEC were incubated with VEGF or tumor necrosis factor alpha (TNF-alpha). Afterwards, the concentration of sVEGFR-2 in the supernatant of unstimulated and stimulated HPEC was measured by ELISA. HPEC showed a typical endothelial morphology. Under cell culture conditions sVEGFR-2 binds VEGF: The measured VEGF concentration in the supernatant of BPH-1 cells was reduced when the fractions of HPEC conditioned medium with the highest sVEGFR-2 concentration were incubated with the BPH-1 cells. The sVEGFR-2 secretion of HPEC was stimulated by VEGF and TNF-alpha. For the first time we report on the secretion of sVEGFR-2 by microvascular endothelial cells of prostate origin. The secretion of sVEGFR-2 by HPEC was stimulated by VEGF and TNF-alpha. Our data suggest that sVEGFR-2 secreted by prostate endothelial cells could modify the effect of VEGF on prostate endothelial and prostate epithelial cells.
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Affiliation(s)
- Axel Stachon
- Institute of Clinical Chemistry, Transfusion, and Laboratory Medicine, BG-University Hospital Bergmannsheil, Ruhr-University of Bochum, Bochum, Germany.
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Thoms S, Erdmann R. Peroxisomal matrix protein receptor ubiquitination and recycling. Biochimica et Biophysica Acta (BBA) - Molecular Cell Research 2006; 1763:1620-8. [PMID: 17028012 DOI: 10.1016/j.bbamcr.2006.08.046] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2006] [Revised: 08/15/2006] [Accepted: 08/23/2006] [Indexed: 11/22/2022]
Abstract
The peroxisomal targeting signal type1 (PTS1) receptor Pex5 is required for the peroxisomal targeting of most matrix proteins. Pex5 recognises target proteins in the cytosol and directs them to the peroxisomal membrane where cargo is released into the matrix, and the receptor shuttles back to the cytosol. Recently, it has become evident that the membrane-bound Pex5 can be modified by mono- and polyubiquitination. This review summarises recent results on Pex5 ubiquitination and on the role of the AAA peroxins Pex1 and Pex6 as dislocases required for the release of Pex5 from the membrane to the cytosol where the receptor is either degraded by proteasomes or made available for another round of protein import into peroxisomes.
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Affiliation(s)
- Sven Thoms
- Abteilung für Systembiochemie, Medizinische Fakultät der Ruhr-Universität Bochum, D-44780 Bochum, Germany
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Abstract
The abundance and size of cellular organelles vary depending on the cell type and metabolic needs. Peroxisomes constitute a class of cellular organelles renowned for their ability to adapt to cellular and environmental conditions. Together with transcriptional regulators, two groups of peroxisomal proteins have a pronounced influence on peroxisome size and abundance. Pex11-type peroxisome proliferators are involved in the proliferation of peroxisomes, defined here as an increase in size and/or number of peroxisomes. Dynamin-related proteins have recently been suggested to be required for the scission of peroxisomal membranes. This review surveys the function of Pex11-type peroxisome proliferators and dynamin-related proteins in peroxisomal proliferation and division.
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Affiliation(s)
- Sven Thoms
- Ruhr-University-Bochum, Medical Faculty, Institute of Physiological Chemistry, Bochum, Germany
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Abstract
The ATPase Cdc48 is required for membrane fusion and protein degradation. Recently it has been suggested that Cdc48 in a complex with Ufd1 and Npl4 acts as an ubiquitin-dependent chaperone. Here it is shown that recombinant Cdc48 alone can distinguish between the native and the non-native conformation of model substrates. First, Cdc48 prevents luciferase from aggregating following a heat shock. Second, it inhibits the aggregation of rhodanese upon dilution. Third, Cdc48 binds specifically to heat-denatured luciferase. These chaperone-like functions seem to be independent of ATPase activity. Furthermore, Cdc48 can act as a co-chaperone in the Hsc70-Hsp40 chaperone system. These results show that Cdc48 possesses chaperone-like activities and can functionally interact with Hsc70. Cdc48's ability to recognise denatured proteins can also be a source of unspecific binding in biochemical interaction experiments.
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Affiliation(s)
- Sven Thoms
- ZMBH, Center for Molecular Biology, Heidelberg University, Im Neuenheimer Feld 282, 69120 Heidelberg, Germany.
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Braun S, Matuschewski K, Rape M, Thoms S, Jentsch S. Role of the ubiquitin-selective CDC48(UFD1/NPL4 )chaperone (segregase) in ERAD of OLE1 and other substrates. EMBO J 2002; 21:615-21. [PMID: 11847109 PMCID: PMC125867 DOI: 10.1093/emboj/21.4.615] [Citation(s) in RCA: 280] [Impact Index Per Article: 12.7] [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: 11/15/2001] [Revised: 12/18/2001] [Accepted: 12/28/2001] [Indexed: 01/19/2023] Open
Abstract
The OLE pathway of yeast regulates the abundance of the ER-bound enzyme Delta-9 fatty acid desaturase OLE1, thereby controlling unsaturated fatty acid pools and membrane fluidity. Previously, we showed that this pathway is exquisitely regulated by the ubiquitin/proteasome system. Activation of the pathway involves proteasomal processing of a membrane-bound transcription factor and the subsequent mobilization of the cleaved, ubiquitylated transcription factor from its partner molecule by CDC48(UFD1/NPL4), a ubiquitin-selective chaperone-like enzyme. Here we report that the OLE1 protein itself is naturally short-lived and is degraded by ubiquitin/proteasome-dependent ER-associated degradation (ERAD). We found that CDC48(UFD1/NPL4) plays a second role in the OLE pathway by mediating ERAD of OLE1. Intriguingly, other ERAD substrates also require CDC48(UFD1/NPL4) for degradation, indicating that this enzyme is a novel, constitutive component of the ERAD machinery. We propose that CDC48(UFD1/NPL4) functions as a segregase that liberates ubiquitylated proteins from non-modified partners.
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Affiliation(s)
- Sigurd Braun
- Department of Molecular Cell Biology, Max Planck Institute of Biochemistry, Am Klopferspitz 18a, D-82152 Martinsried and ZMBH, Center for Molecular Biology, Heidelberg University, Im Neuenheimer Feld 282, D-69120 Heidelberg, Germany Present address: Department of Parasitology, Heidelberg University School of Medicine, Im Neuenheimer Feld 324, D-69120 Heidelberg, Germany Present address: Friedrich Miescher Laboratory of the Max Planck Society, Spemannstrasse 39, D-72076 Tübingen, Germany Corresponding author e-mail:
| | - Kai Matuschewski
- Department of Molecular Cell Biology, Max Planck Institute of Biochemistry, Am Klopferspitz 18a, D-82152 Martinsried and ZMBH, Center for Molecular Biology, Heidelberg University, Im Neuenheimer Feld 282, D-69120 Heidelberg, Germany Present address: Department of Parasitology, Heidelberg University School of Medicine, Im Neuenheimer Feld 324, D-69120 Heidelberg, Germany Present address: Friedrich Miescher Laboratory of the Max Planck Society, Spemannstrasse 39, D-72076 Tübingen, Germany Corresponding author e-mail:
| | - Michael Rape
- Department of Molecular Cell Biology, Max Planck Institute of Biochemistry, Am Klopferspitz 18a, D-82152 Martinsried and ZMBH, Center for Molecular Biology, Heidelberg University, Im Neuenheimer Feld 282, D-69120 Heidelberg, Germany Present address: Department of Parasitology, Heidelberg University School of Medicine, Im Neuenheimer Feld 324, D-69120 Heidelberg, Germany Present address: Friedrich Miescher Laboratory of the Max Planck Society, Spemannstrasse 39, D-72076 Tübingen, Germany Corresponding author e-mail:
| | - Sven Thoms
- Department of Molecular Cell Biology, Max Planck Institute of Biochemistry, Am Klopferspitz 18a, D-82152 Martinsried and ZMBH, Center for Molecular Biology, Heidelberg University, Im Neuenheimer Feld 282, D-69120 Heidelberg, Germany Present address: Department of Parasitology, Heidelberg University School of Medicine, Im Neuenheimer Feld 324, D-69120 Heidelberg, Germany Present address: Friedrich Miescher Laboratory of the Max Planck Society, Spemannstrasse 39, D-72076 Tübingen, Germany Corresponding author e-mail:
| | - Stefan Jentsch
- Department of Molecular Cell Biology, Max Planck Institute of Biochemistry, Am Klopferspitz 18a, D-82152 Martinsried and ZMBH, Center for Molecular Biology, Heidelberg University, Im Neuenheimer Feld 282, D-69120 Heidelberg, Germany Present address: Department of Parasitology, Heidelberg University School of Medicine, Im Neuenheimer Feld 324, D-69120 Heidelberg, Germany Present address: Friedrich Miescher Laboratory of the Max Planck Society, Spemannstrasse 39, D-72076 Tübingen, Germany Corresponding author e-mail:
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Abstract
A generic chloroplast-based model for the carbon concentrating mechanism (CCM) in eukaryotic algae is presented. The fine structure of chloroplasts is represented by separate compartments: marginal and bulk stroma, pyrenoid, girdle lamella, bulk thylakoids, and central lamella traversing the pyrenoid. The roles of the individual structural elements of the chloroplast with respect to the CCM and the effect of carbonic anhydrase activity in various compartments are analysed. Hypothetical HCO(-)(3)transport into the acidic thylakoid lumen is adjusted by imposing an optimization principle: a given [CO(2)] at the site of RuBisCO is achieved with minimum energy costs for the CCM. Our model is highly efficient in terms of saturation of RuBisCO carboxylase activity and the affinity of the chloroplast for CO(2), if either a girdle lamella or a pyrenoid is present. The highest efficiency is achieved with a pyrenoid. A eukaryotic CCM is not necessarily associated with accumulation of dissolved inorganic carbon (DIC) as in cyanobacteria. Chloroplasts are categorized into four types corresponding to morphological characteristics of all major algal classes with regard to the presence of pyrenoids, girdle lamellae, and the distribution of CA activity.
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Affiliation(s)
- S Thoms
- Alfred-Wegener-Institute for Polar and Marine Research, P.O. Box 1201 61, D-27515 Bremerhaven, Germany
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Everall LA, Sugden K, Williams JA, Bennion I, Liu X, Aitchison JS, Thoms S, De La Rue RM. Fabrication of multipassband moiré resonators in fibers by the dual-phase-mask exposure method. Opt Lett 1997; 22:1473-1475. [PMID: 18188272 DOI: 10.1364/ol.22.001473] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
We report on the fabrication of in-fiber moiré filters by dual exposure of a nondedicated chirped phase mask. This simple technique produces broadband filters whose structure depends only on an intermediate stretch between two identical UV exposures. We demonstrate moiré filters with as many as four narrow passbands within a 2-nm stopband.
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Kleinert H, Thoms S. Large-order behavior of a two-coupling-constant phi4 theory with cubic anisotropy. Phys Rev D Part Fields 1995; 52:5926-5943. [PMID: 10019125 DOI: 10.1103/physrevd.52.5926] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Gallagher BL, Galloway T, Beton P, Oxley JP, Beaumont SP, Thoms S, Wilkinson CD. Observation of universal thermopower fluctuations. Phys Rev Lett 1990; 64:2058-2061. [PMID: 10041566 DOI: 10.1103/physrevlett.64.2058] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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