1
|
Jain N, Gomkale R, Bernhard O, Rehling P, Cruz-Zaragoza LD. A quantitative fluorescence-based approach to study mitochondrial protein import. EMBO Rep 2023; 24:e55760. [PMID: 36938994 PMCID: PMC10157374 DOI: 10.15252/embr.202255760] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2022] [Revised: 01/22/2023] [Accepted: 02/17/2023] [Indexed: 03/21/2023] Open
Abstract
Mitochondria play central roles in cellular energy production and metabolism. Most proteins required to carry out these functions are synthesized in the cytosol and imported into mitochondria. A growing number of metabolic disorders arising from mitochondrial dysfunction can be traced to errors in mitochondrial protein import. The mechanisms underlying the import of precursor proteins are commonly studied using radioactively labeled precursor proteins imported into purified mitochondria. Here, we establish a fluorescence-based import assay to analyze protein import into mitochondria. We show that fluorescently labeled precursors enable import analysis with similar sensitivity to those using radioactive precursors, yet they provide the advantage of quantifying import with picomole resolution. We adapted the import assay to a 96-well plate format allowing for fast analysis in a screening-compatible format. Moreover, we show that fluorescently labeled precursors can be used to monitor the assembly of the F1 F0 ATP synthase in purified mitochondria. Thus, we provide a sensitive fluorescence-based import assay that enables quantitative and fast import analysis.
Collapse
Affiliation(s)
- Naintara Jain
- Department of Cellular Biochemistry, University Medical Center Göttingen, Göttingen, Germany
| | - Ridhima Gomkale
- Department of Cellular Biochemistry, University Medical Center Göttingen, Göttingen, Germany
| | - Olaf Bernhard
- Department of Cellular Biochemistry, University Medical Center Göttingen, Göttingen, Germany
| | - Peter Rehling
- Department of Cellular Biochemistry, University Medical Center Göttingen, Göttingen, Germany.,Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Göttingen, Germany.,Max Planck Institute for Multidisciplinary Science, Göttingen, Germany
| | | |
Collapse
|
2
|
Chowdhury A, Aich A, Jain G, Wozny K, Lüchtenborg C, Hartmann M, Bernhard O, Balleiniger M, Alfar EA, Zieseniss A, Toischer K, Guan K, Rizzoli SO, Brügger B, Fischer A, Katschinski DM, Rehling P, Dudek J. Defective Mitochondrial Cardiolipin Remodeling Dampens HIF-1α Expression in Hypoxia. Cell Rep 2019; 25:561-570.e6. [PMID: 30332638 PMCID: PMC6205837 DOI: 10.1016/j.celrep.2018.09.057] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Revised: 08/20/2018] [Accepted: 09/17/2018] [Indexed: 12/28/2022] Open
Abstract
Mitochondria fulfill vital metabolic functions and act as crucial cellular signaling hubs, integrating their metabolic status into the cellular context. Here, we show that defective cardiolipin remodeling, upon loss of the cardiolipin acyl transferase tafazzin, decreases HIF-1α signaling in hypoxia. Tafazzin deficiency does not affect posttranslational HIF-1α regulation but rather HIF-1α gene expression, a dysfunction recapitulated in iPSC-derived cardiomyocytes from Barth syndrome patients with tafazzin deficiency. RNA-seq analyses confirmed drastically altered signaling in tafazzin mutant cells. In hypoxia, tafazzin-deficient cells display reduced production of reactive oxygen species (ROS) perturbing NF-κB activation and concomitantly HIF-1α gene expression. Tafazzin-deficient mice hearts display reduced HIF-1α levels and undergo maladaptive hypertrophy with heart failure in response to pressure overload challenge. We conclude that defective mitochondrial cardiolipin remodeling dampens HIF-1α signaling due to a lack of NF-κB activation through reduced mitochondrial ROS production, decreasing HIF-1α transcription. Defective remodeling of mitochondrial cardiolipin dampens HIF-1α signaling ROS-mediated NF-κB activation is impaired in cardiolipin-deficient cells Defective NF-κB-mediated HIF-1α gene induction decreases the cellular response to hypoxia Deregulated cardiac response to pressure overload in Barth syndrome mouse
Collapse
Affiliation(s)
- Arpita Chowdhury
- Department of Cellular Biochemistry, University Medical Center Göttingen, GZMB, 37073 Göttingen, Germany
| | - Abhishek Aich
- Department of Cellular Biochemistry, University Medical Center Göttingen, GZMB, 37073 Göttingen, Germany
| | - Gaurav Jain
- Department for Epigenetics and Systems Medicine in Neurodegenerative Diseases, German Center for Neurodegenerative Diseases (DZNE) Göttingen, Göttingen, Germany
| | - Katharina Wozny
- Heidelberg University Biochemistry Center (BZH), University of Heidelberg, Heidelberg 69120, Germany
| | - Christian Lüchtenborg
- Heidelberg University Biochemistry Center (BZH), University of Heidelberg, Heidelberg 69120, Germany
| | - Magnus Hartmann
- Department of Cellular Biochemistry, University Medical Center Göttingen, GZMB, 37073 Göttingen, Germany
| | - Olaf Bernhard
- Department of Cellular Biochemistry, University Medical Center Göttingen, GZMB, 37073 Göttingen, Germany
| | - Martina Balleiniger
- Department of Cellular Biochemistry, University Medical Center Göttingen, GZMB, 37073 Göttingen, Germany
| | - Ezzaldin Ahmed Alfar
- Institute of Pharmacology and Toxicology, Technische Universität Dresden, Dresden, Germany
| | - Anke Zieseniss
- Institute of Cardiovascular Physiology, University Medical Center Göttingen, Göttingen, Germany
| | - Karl Toischer
- Department of Cardiology and Pneumology, University Medical Center Göttingen, Göttingen, Germany; German Center for Cardiovascular Research (DZHK), Göttingen, Germany
| | - Kaomei Guan
- Institute of Pharmacology and Toxicology, Technische Universität Dresden, Dresden, Germany
| | - Silvio O Rizzoli
- Department of Neuro- and Sensory Physiology, University Medical Center Göttingen, Göttingen, Germany
| | - Britta Brügger
- Heidelberg University Biochemistry Center (BZH), University of Heidelberg, Heidelberg 69120, Germany
| | - Andrè Fischer
- Department for Epigenetics and Systems Medicine in Neurodegenerative Diseases, German Center for Neurodegenerative Diseases (DZNE) Göttingen, Göttingen, Germany; Department of Psychiatry and Psychotherapy, University Medical Center Göttingen, Göttingen, Germany
| | - Dörthe M Katschinski
- Institute of Cardiovascular Physiology, University Medical Center Göttingen, Göttingen, Germany
| | - Peter Rehling
- Department of Cellular Biochemistry, University Medical Center Göttingen, GZMB, 37073 Göttingen, Germany; Max Planck Institute for Biophysical Chemistry, 37073, Göttingen, Germany.
| | - Jan Dudek
- Department of Cellular Biochemistry, University Medical Center Göttingen, GZMB, 37073 Göttingen, Germany
| |
Collapse
|
3
|
Schlotawa L, Wachs M, Bernhard O, Mayer FJ, Dierks T, Schmidt B, Radhakrishnan K. Recognition and ER Quality Control of Misfolded Formylglycine-Generating Enzyme by Protein Disulfide Isomerase. Cell Rep 2019; 24:27-37.e4. [PMID: 29972788 DOI: 10.1016/j.celrep.2018.06.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [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: 07/31/2017] [Revised: 04/12/2018] [Accepted: 06/01/2018] [Indexed: 11/19/2022] Open
Abstract
Multiple sulfatase deficiency (MSD) is a fatal, inherited lysosomal storage disorder characterized by reduced activities of all sulfatases in patients. Sulfatases require a unique post-translational modification of an active-site cysteine to formylglycine that is catalyzed by the formylglycine-generating enzyme (FGE). FGE mutations that affect intracellular protein stability determine residual enzyme activity and disease severity in MSD patients. Here, we show that protein disulfide isomerase (PDI) plays a pivotal role in the recognition and quality control of MSD-causing FGE variants. Overexpression of PDI reduces the residual activity of unstable FGE variants, whereas inhibition of PDI function rescues the residual activity of sulfatases in MSD fibroblasts. Mass spectrometric analysis of a PDI+FGE variant covalent complex allowed determination of the molecular signature for FGE recognition by PDI. Our findings highlight the role of PDI as a disease modifier in MSD, which may also be relevant for other ER-associated protein folding pathologies.
Collapse
Affiliation(s)
- Lars Schlotawa
- Department of Medical Genetics, University of Cambridge, Cambridge Institute for Medical Research, Cambridge CB2 0XY, UK
| | - Michaela Wachs
- Department of Chemistry, Biochemistry I, Bielefeld University, Universitätsstraße 25, 33615 Bielefeld, Germany
| | - Olaf Bernhard
- Department of Cellular Biochemistry, University of Göttingen, Humboldtallee 23, 37073 Göttingen, Germany
| | - Franz J Mayer
- Bruker Daltonik GmbH, Fahrenheitstraße 4, 28359 Bremen, Germany
| | - Thomas Dierks
- Department of Chemistry, Biochemistry I, Bielefeld University, Universitätsstraße 25, 33615 Bielefeld, Germany.
| | - Bernhard Schmidt
- Department of Cellular Biochemistry, University of Göttingen, Humboldtallee 23, 37073 Göttingen, Germany.
| | - Karthikeyan Radhakrishnan
- Department of Chemistry, Biochemistry I, Bielefeld University, Universitätsstraße 25, 33615 Bielefeld, Germany; Department of Cellular Biochemistry, University of Göttingen, Humboldtallee 23, 37073 Göttingen, Germany.
| |
Collapse
|
4
|
Abstract
The reconstruction of functionally appropriate contacts between antagonistic teeth substantially determines the quality of prosthetic-restorative work. In a population-based sample comprising 2597 subjects, static occlusal contacts were registered and analysed using the GEDAS (Greifswald Digital Analyzing System), which digitally represents the contact point situation by means of silicone bite impressions. The number of contacting teeth is approximately equal on the Left- and right-hand side amounting to 8.3 on the left and 8.4 on the right. Furthermore, it was shown that 39% of the maxillary bridge pontics and 33% of the mandibular bridge units are not in contact. Antagonistic contacts are missing in 41% of the maxillary and 39% of the mandibular removable denture teeth. These results show that the fabrication of fixed dentures, particularly in bridge pontics, and the inspection of removable dentures needs to be done with more care to this detail.
Collapse
Affiliation(s)
- Daniel Hützen
- Poliklinik für zahnärztliche Prothetik, Alterszahnheilkunde und medizinische Werkstoffkunde, Zentrum für Zahn-, Mund- und Kieferheilkunde, Ernst-Moritz-Arndt Universität Greifswald, Rotgerberstrasse 8, D-17475 Greifswald, Germany.
| | | | | | | | | | | | | |
Collapse
|
5
|
Mack F, Mundt T, Ellis J, Schwahn C, Bernhard O, Proff P, Gedrange T, Kocher T, Biffar R. Partial- or full-mouth examination assessing the dental and prosthetic status among elderly individuals. Eur J Prosthodont Restor Dent 2006; 14:158-62. [PMID: 17205950] [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] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
The aim of this study was to determine whether half-mouth examinations accurately reflect the dental and prosthetic status of the entire mouth. Samples of 1,830 adults aged 55- 79 years were examined. The rate of agreement between half- and full-mouth examinations was estimated using weighted and unweighted Kappa values comparing findings of each tooth bilaterally. A power analysis was performed to estimate the number of subjects representing complete dental recordings within a certain power. Subjects showed unweighted Kappa values from 0.34-0.96. Weighted Kappa values ranged from 0. 74-0.99. A power analysis for unweighted Kappa scores computed that.findings from 122-335 individuals were necessary to equal the results obtained using complete dental recordings.
Collapse
Affiliation(s)
- Florian Mack
- School of Dentistry and Oral Health, Griffith University, Queensland, Australia.
| | | | | | | | | | | | | | | | | |
Collapse
|
6
|
Abstract
Heterotetrameric adaptor-protein complexes AP-1A and AP-3A mediate protein sorting in post-Golgi vesicular transport. AP-1A and AP-3A have been localized to the trans-Golgi network, indicating a function in protein sorting at this compartment. AP-3A appears to mediate trans-Golgi network-to-lysosome and also endosome-to-lysosome protein sorting. AP-1A is thought to be required for both trans-Golgi network-to-endosome transport and endosome-to-trans-Golgi network transport. However, the recent discovery of a role for monomeric GGA (Golgi localized gamma-ear containing, ARF binding protein) adaptor proteins in trans-Golgi network to endosome protein transport has brought into question the long-discussed trans-Golgi network-to-endosome sorting function of AP-1A. Murine cytomegalovirus gp48 contains an unusual di-leucine-based lysosome sorting signal motif and mediates lysosomal sorting of gp48/major histocompatibility complex class I receptor complexes, preventing exposure of major histocompatibility complex class I at the plasma membrane. We analyzed lysosomal sorting of gp48/major histocompatibility complex class I receptor complexes in cell lines deficient for AP-1A, AP-3A and both, to determine their sorting functions. We find that AP1-A and AP3-A mediate distinct and sequential steps in the lysosomal sorting. Both sorting functions are required to prevent MHC class I exposure at the plasma membrane at steady-state.
Collapse
Affiliation(s)
- Uwe Reusch
- Zentrum für Biochemie and Molekulare Zellbiologie, Department of Biochemie II, Universität Göttingen, Heinrich-Düker-Weg 12, D-37073 Göttingen, Germany
| | | | | | | |
Collapse
|
7
|
Reuter T, Herterich S, Bernhard O, Hoehn H, Gross HJ. Strong FANCA/FANCG but weak FANCA/FANCC interaction in the yeast 2-hybrid system. Blood 2000; 95:719-20. [PMID: 10627486] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023] Open
Abstract
Three of at least 8 Fanconi anemia (FA) genes have been cloned (FANCA, FANCC, FANCG), but their functions remain unknown. Using the yeast 2-hybrid system and full-length cDNA, the authors found a strong interaction between FANCA and FANCG proteins. They also obtained evidence for a weak interaction between FANCA and FANCC. Neither FANCA nor FANCC was found to interact with itself. These results support the notion of a functional association between the FA gene products. (Blood. 2000;95:719-720)
Collapse
Affiliation(s)
- T Reuter
- Departments of Biochemistry and Human Genetics, University of Würzburg, Würzburg, Germany.
| | | | | | | | | |
Collapse
|