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Eldeeb MH, Camacho Lopez LJ, Fontanesi F. Mitochondrial respiratory supercomplexes of the yeast Saccharomyces cerevisiae. IUBMB Life 2024. [PMID: 38529880 DOI: 10.1002/iub.2817] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Accepted: 02/28/2024] [Indexed: 03/27/2024]
Abstract
The functional and structural relationship among the individual components of the mitochondrial respiratory chain constitutes a central aspect of our understanding of aerobic catabolism. This interplay has been a subject of intense debate for over 50 years. It is well established that individual respiratory enzymes associate into higher-order structures known as respiratory supercomplexes, which represent the evolutionarily conserved organizing principle of the mitochondrial respiratory chain. In the yeast Saccharomyces cerevisiae, supercomplexes are formed by a complex III homodimer flanked by one or two complex IV monomers, and their high-resolution structures have been recently elucidated. Despite the wealth of structural information, several proposed supercomplex functions remain speculative and our understanding of their physiological relevance is still limited. Recent advances in the field were made possible by the construction of yeast strains where the association of complex III and IV into supercomplexes is impeded, leading to diminished respiratory capacity and compromised cellular competitive fitness. Here, we discuss the experimental evidence and hypotheses relative to the functional roles of yeast respiratory supercomplexes. Moreover, we review the current models of yeast complex III and IV assembly in the context of supercomplex formation and highlight the data scattered throughout the literature suggesting the existence of cross talk between their biogenetic processes.
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Affiliation(s)
- Mazzen H Eldeeb
- Department of Biochemistry and Molecular Biology, University of Miami, Miller School of Medicine, Miami, Florida, USA
| | - Lizeth J Camacho Lopez
- Department of Biochemistry and Molecular Biology, University of Miami, Miller School of Medicine, Miami, Florida, USA
| | - Flavia Fontanesi
- Department of Biochemistry and Molecular Biology, University of Miami, Miller School of Medicine, Miami, Florida, USA
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2
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Horten P, Song K, Garlich J, Hardt R, Colina-Tenorio L, Horvath SE, Schulte U, Fakler B, van der Laan M, Becker T, Stuart RA, Pfanner N, Rampelt H. Identification of MIMAS, a multifunctional mega-assembly integrating metabolic and respiratory biogenesis factors of mitochondria. Cell Rep 2024; 43:113772. [PMID: 38393949 PMCID: PMC11010658 DOI: 10.1016/j.celrep.2024.113772] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Revised: 01/03/2024] [Accepted: 01/24/2024] [Indexed: 02/25/2024] Open
Abstract
The mitochondrial inner membrane plays central roles in bioenergetics and metabolism and contains several established membrane protein complexes. Here, we report the identification of a mega-complex of the inner membrane, termed mitochondrial multifunctional assembly (MIMAS). Its large size of 3 MDa explains why MIMAS has escaped detection in the analysis of mitochondria so far. MIMAS combines proteins of diverse functions from respiratory chain assembly to metabolite transport, dehydrogenases, and lipid biosynthesis but not the large established supercomplexes of the respiratory chain, ATP synthase, or prohibitin scaffold. MIMAS integrity depends on the non-bilayer phospholipid phosphatidylethanolamine, in contrast to respiratory supercomplexes whose stability depends on cardiolipin. Our findings suggest that MIMAS forms a protein-lipid mega-assembly in the mitochondrial inner membrane that integrates respiratory biogenesis and metabolic processes in a multifunctional platform.
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Affiliation(s)
- Patrick Horten
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany; Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany
| | - Kuo Song
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany
| | - Joshua Garlich
- Department of Biological Sciences, Marquette University, Milwaukee, WI 53233, USA
| | - Robert Hardt
- Institute of Biochemistry and Molecular Biology, Faculty of Medicine, University of Bonn, 53115 Bonn, Germany
| | - Lilia Colina-Tenorio
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany
| | - Susanne E Horvath
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany
| | - Uwe Schulte
- Institute of Physiology, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany; CIBSS Centre for Integrative Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany
| | - Bernd Fakler
- Institute of Physiology, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany; CIBSS Centre for Integrative Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany; BIOSS Centre for Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany
| | - Martin van der Laan
- Medical Biochemistry and Molecular Biology, Center for Molecular Signaling, PZMS, Faculty of Medicine, Saarland University, 66421 Homburg, Germany
| | - Thomas Becker
- Institute of Biochemistry and Molecular Biology, Faculty of Medicine, University of Bonn, 53115 Bonn, Germany
| | - Rosemary A Stuart
- Department of Biological Sciences, Marquette University, Milwaukee, WI 53233, USA
| | - Nikolaus Pfanner
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany; CIBSS Centre for Integrative Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany; BIOSS Centre for Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany.
| | - Heike Rampelt
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany; CIBSS Centre for Integrative Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany.
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3
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Veloso Ribeiro Franco L, Barros MH. Biolistic transformation of the yeast Saccharomyces cerevisiae mitochondrial DNA. IUBMB Life 2023; 75:972-982. [PMID: 37470229 DOI: 10.1002/iub.2769] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Accepted: 06/23/2023] [Indexed: 07/21/2023]
Abstract
The insertion of genes into mitochondria by biolistic transformation is currently only possible in the yeast Saccharomyces cerevisiae and the algae Chlamydomonas reinhardtii. The fact that S. cerevisiae mitochondria can exist with partial (ρ- mutants) or complete deletions (ρ0 mutants) of mitochondrial DNA (mtDNA), without requiring a specific origin of replication, enables the propagation of exogenous sequences. Additionally, mtDNA in this organism undergoes efficient homologous recombination, making it well-suited for genetic manipulation. In this review, we present a summarized historical overview of the development of biolistic transformation and discuss iconic applications of the technique. We also provide a detailed example on how to obtain transformants with recombined foreign DNA in their mitochondrial genome.
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Affiliation(s)
| | - Mario H Barros
- Department of Microbiology, Institute of Biomedical Sciences, Universidade de Sao Paulo, Sao Paulo, Brazil
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4
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Kohler A, Barrientos A, Fontanesi F, Ott M. The functional significance of mitochondrial respiratory chain supercomplexes. EMBO Rep 2023; 24:e57092. [PMID: 37828827 PMCID: PMC10626428 DOI: 10.15252/embr.202357092] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 07/10/2023] [Accepted: 09/14/2023] [Indexed: 10/14/2023] Open
Abstract
The mitochondrial respiratory chain (MRC) is a key energy transducer in eukaryotic cells. Four respiratory chain complexes cooperate in the transfer of electrons derived from various metabolic pathways to molecular oxygen, thereby establishing an electrochemical gradient over the inner mitochondrial membrane that powers ATP synthesis. This electron transport relies on mobile electron carries that functionally connect the complexes. While the individual complexes can operate independently, they are in situ organized into large assemblies termed respiratory supercomplexes. Recent structural and functional studies have provided some answers to the question of whether the supercomplex organization confers an advantage for cellular energy conversion. However, the jury is still out, regarding the universality of these claims. In this review, we discuss the current knowledge on the functional significance of MRC supercomplexes, highlight experimental limitations, and suggest potential new strategies to overcome these obstacles.
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Affiliation(s)
- Andreas Kohler
- Department of Biochemistry and BiophysicsStockholm UniversityStockholmSweden
- Institute of Molecular BiosciencesUniversity of GrazGrazAustria
| | - Antoni Barrientos
- Department of Neurology, Miller School of MedicineUniversity of MiamiMiamiFLUSA
- Department of Biochemistry and Molecular Biology, Miller School of MedicineUniversity of MiamiMiamiFLUSA
| | - Flavia Fontanesi
- Department of Biochemistry and Molecular Biology, Miller School of MedicineUniversity of MiamiMiamiFLUSA
| | - Martin Ott
- Department of Biochemistry and BiophysicsStockholm UniversityStockholmSweden
- Department of Medical Biochemistry and Cell BiologyUniversity of GothenburgGothenburgSweden
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5
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Franco LVR, Su CH, Simas Teixeira L, Almeida Clarck Chagas J, Barros MH, Tzagoloff A. Allotopic expression of COX6 elucidates Atco-driven co-assembly of cytochrome oxidase and ATP synthase. Life Sci Alliance 2023; 6:e202301965. [PMID: 37604582 PMCID: PMC10442929 DOI: 10.26508/lsa.202301965] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 08/03/2023] [Accepted: 08/07/2023] [Indexed: 08/23/2023] Open
Abstract
The Cox6 subunit of Saccharomyces cerevisiae cytochrome oxidase (COX) and the Atp9 subunit of the ATP synthase are encoded in nuclear and mitochondrial DNA, respectively. The two proteins interact to form Atco complexes that serve as the source of Atp9 for ATP synthase assembly. To determine if Atco is also a precursor of COX, we pulse-labeled Cox6 in isolated mitochondria of a cox6 nuclear mutant with COX6 in mitochondrial DNA. Only a small fraction of the newly translated Cox6 was found to be present in Atco, which can explain the low concentration of COX and poor complementation of the cox6 mutation by the allotopic gene. This and other pieces of evidence presented in this study indicate that Atco is an obligatory source of Cox6 for COX biogenesis. Together with our finding that atp9 mutants fail to assemble COX, we propose a regulatory model in which Atco unidirectionally couples the biogenesis of COX to that of the ATP synthase to maintain a proper ratio of these two complexes of oxidative phosphorylation.
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Affiliation(s)
- Leticia Veloso R Franco
- https://ror.org/00hj8s172 Department of Biological Sciences, Columbia University, New York, NY, USA
- https://ror.org/036rp1748 Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brasil
| | - Chen-Hsien Su
- https://ror.org/00hj8s172 Department of Biological Sciences, Columbia University, New York, NY, USA
| | - Lorisa Simas Teixeira
- https://ror.org/00hj8s172 Department of Biological Sciences, Columbia University, New York, NY, USA
| | | | - Mario Henrique Barros
- https://ror.org/036rp1748 Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brasil
| | - Alexander Tzagoloff
- https://ror.org/00hj8s172 Department of Biological Sciences, Columbia University, New York, NY, USA
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Cryo-EM structure and function of S. pombe complex IV with bound respiratory supercomplex factor. Commun Chem 2023; 6:32. [PMID: 36797353 PMCID: PMC9935853 DOI: 10.1038/s42004-023-00827-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Accepted: 01/31/2023] [Indexed: 02/18/2023] Open
Abstract
Fission yeast Schizosaccharomyces pombe serves as model organism for studying higher eukaryotes. We combined the use of cryo-EM and spectroscopy to investigate the structure and function of affinity purified respiratory complex IV (CIV) from S. pombe. The reaction sequence of the reduced enzyme with O2 proceeds over a time scale of µs-ms, similar to that of the mammalian CIV. The cryo-EM structure of CIV revealed eleven subunits as well as a bound hypoxia-induced gene 1 (Hig1) domain of respiratory supercomplex factor 2 (Rcf2). These results suggest that binding of Rcf2 does not require the presence of a CIII-CIV supercomplex, i.e. Rcf2 is a component of CIV. An AlphaFold-Multimer model suggests that the Hig1 domains of both Rcf1 and Rcf2 bind at the same site of CIV suggesting that their binding is mutually exclusive. Furthermore, the differential functional effect of Rcf1 or Rcf2 is presumably caused by interactions of CIV with their different non-Hig1 domain parts.
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7
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Yang G, Zhao T, Lu S, Weng J, Zeng X. T1121G Point Mutation in the Mitochondrial Gene COX1 Suppresses a Null Mutation in ATP23 Required for the Assembly of Yeast Mitochondrial ATP Synthase. Int J Mol Sci 2022; 23:ijms23042327. [PMID: 35216443 PMCID: PMC8877559 DOI: 10.3390/ijms23042327] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 02/10/2022] [Accepted: 02/16/2022] [Indexed: 02/04/2023] Open
Abstract
Nuclear-encoded Atp23 was previously shown to have dual functions, including processing the yeast Atp6 precursor and assisting the assembly of yeast mitochondrial ATP synthase. However, it remains unknown whether there are genes functionally complementary to ATP23 to rescue atp23 null mutant. In the present paper, we screen and characterize three revertants of atp23 null mutant and reveal a T1121G point mutation in the mitochondrial gene COX1 coding sequence, which leads to Val374Gly mutation in Cox1, the suppressor in the revertants. This was verified further by the partial restoration of mitochondrial ATP synthase assembly in atp23 null mutant transformed with exogenous hybrid COX1 T1121G mutant plasmid. The predicted tertiary structure of the Cox1 p.Val374Gly mutation showed no obvious difference from wild-type Cox1. By further chase labeling with isotope [35S]-methionine, we found that the stability of Atp6 of ATP synthase increased in the revertants compared with the atp23 null mutant. Taking all the data together, we revealed that the T1121G point mutation of mitochondrial gene COX1 could partially restore the unassembly of mitochondrial ATP synthase in atp23 null mutant by increasing the stability of Atp6. Therefore, this study uncovers a gene that is partially functionally complementary to ATP23 to rescue ATP23 deficiency, broadening our understanding of the relationship between yeast the cytochrome c oxidase complex and mitochondrial ATP synthase complex.
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8
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Rcf proteins and their differential specificity for respiratory chain complexes: A unique role for Rcf2 on oxygen sensitive supercomplexes? BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2021; 1868:119133. [PMID: 34450214 DOI: 10.1016/j.bbamcr.2021.119133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 08/18/2021] [Accepted: 08/21/2021] [Indexed: 11/22/2022]
Abstract
The respiratory chain, embedded in the inner mitochondrial membrane, is organized as a network of individual complexes, as well as large supercomplex structures. In the yeast S. cerevisiae, these supercomplexes consist of a dimeric cytochrome bc1-complex adjoined by one or two copies of cytochrome c oxidase. The formation of these complexes is a dynamic process and is regulated by various factors in order to adapt to environmental and metabolic changes. These adaptions occur at the level of enzyme regulation, complex assembly, as well as altered nuclear and mitochondrial transcription and translation. Members of the Rcf protein family (Rcf1, Rcf2 and Rcf3) are required for respiratory complex biogenesis and act mainly by regulating the assembly and enzyme activity of complex IV within supercomplexes. Rcf1 functions in the assembly process via the COX3 module, whereas Rcf2 and Rcf3 are responsible for enzymatic regulation. In this study, we have extended this knowledge to show that Rcf2 and Rcf3 can also associate with newly synthesized mitochondrial encoded proteins, such as Cox3, and therefore contribute to complex IV assembly. Since the Rcf proteins have overlapping regions of sequence similarities, we engineered novel fusion proteins of Rcf1 and Rcf3, with parts of Rcf2, to probe which of the Rcf protein domains can be attributed to their functions. The fusion proteins could compensate for the individual phenotypes of the complexIV assembly defect and the lack of complex IV regulation. Finally, the role of Rcf proteins for defined species of respiratory chain complexes in a hypoxic model was investigated, uncovering a unique association of Rcf2 with the hypoxic III2IV supercomplex. We therefore suggest an involvement of Rcf2 for adaption of the respiratory chain to altering oxygen levels.
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9
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Brzezinski P, Moe A, Ädelroth P. Structure and Mechanism of Respiratory III-IV Supercomplexes in Bioenergetic Membranes. Chem Rev 2021; 121:9644-9673. [PMID: 34184881 PMCID: PMC8361435 DOI: 10.1021/acs.chemrev.1c00140] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Indexed: 12/12/2022]
Abstract
In the final steps of energy conservation in aerobic organisms, free energy from electron transfer through the respiratory chain is transduced into a proton electrochemical gradient across a membrane. In mitochondria and many bacteria, reduction of the dioxygen electron acceptor is catalyzed by cytochrome c oxidase (complex IV), which receives electrons from cytochrome bc1 (complex III), via membrane-bound or water-soluble cytochrome c. These complexes function independently, but in many organisms they associate to form supercomplexes. Here, we review the structural features and the functional significance of the nonobligate III2IV1/2 Saccharomyces cerevisiae mitochondrial supercomplex as well as the obligate III2IV2 supercomplex from actinobacteria. The analysis is centered around the Q-cycle of complex III, proton uptake by CytcO, as well as mechanistic and structural solutions to the electronic link between complexes III and IV.
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Affiliation(s)
- Peter Brzezinski
- Department of Biochemistry and Biophysics,
The Arrhenius Laboratories for Natural Sciences, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Agnes Moe
- Department of Biochemistry and Biophysics,
The Arrhenius Laboratories for Natural Sciences, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Pia Ädelroth
- Department of Biochemistry and Biophysics,
The Arrhenius Laboratories for Natural Sciences, Stockholm University, SE-106 91 Stockholm, Sweden
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10
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Franco LVR, Su CH, Tzagoloff A. Modular assembly of yeast mitochondrial ATP synthase and cytochrome oxidase. Biol Chem 2021; 401:835-853. [PMID: 32142477 DOI: 10.1515/hsz-2020-0112] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Accepted: 02/24/2020] [Indexed: 12/27/2022]
Abstract
The respiratory pathway of mitochondria is composed of four electron transfer complexes and the ATP synthase. In this article, we review evidence from studies of Saccharomyces cerevisiae that both ATP synthase and cytochrome oxidase (COX) are assembled from independent modules that correspond to structurally and functionally identifiable components of each complex. Biogenesis of the respiratory chain requires a coordinate and balanced expression of gene products that become partner subunits of the same complex, but are encoded in the two physically separated genomes. Current evidence indicates that synthesis of two key mitochondrial encoded subunits of ATP synthase is regulated by the F1 module. Expression of COX1 that codes for a subunit of the COX catalytic core is also regulated by a mechanism that restricts synthesis of this subunit to the availability of a nuclear-encoded translational activator. The respiratory chain must maintain a fixed stoichiometry of the component enzyme complexes during cell growth. We propose that high-molecular-weight complexes composed of Cox6, a subunit of COX, and of the Atp9 subunit of ATP synthase play a key role in establishing the ratio of the two complexes during their assembly.
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Affiliation(s)
- Leticia Veloso Ribeiro Franco
- Department of Biological Sciences, Columbia University, New York City, NY 10027, USA.,Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, 05508-000, Brasil
| | - Chen Hsien Su
- Department of Biological Sciences, Columbia University, New York City, NY 10027, USA
| | - Alexander Tzagoloff
- Department of Biological Sciences, Columbia University, New York City, NY 10027, USA
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11
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Distinct Roles of Mitochondrial HIGD1A and HIGD2A in Respiratory Complex and Supercomplex Biogenesis. Cell Rep 2021; 31:107607. [PMID: 32375044 DOI: 10.1016/j.celrep.2020.107607] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 03/06/2020] [Accepted: 04/10/2020] [Indexed: 01/08/2023] Open
Abstract
The mitochondrial respiratory chain enzymes are organized as individual complexes and supercomplexes, whose biogenesis remains to be fully understood. To disclose the role of the human Hypoxia Inducible Gene Domain family proteins HIGD1A and HIGD2A in these processes, we generate and characterize HIGD-knockout (KO) cell lines. We show that HIGD2A controls and coordinates the modular assembly of isolated and supercomplexed complex IV (CIV) by acting on the COX3 assembly module. In contrast, HIGD1A regulates CIII and CIII-containing supercomplex biogenesis by supporting the incorporation of UQCRFS1. HIGD1A also clusters with COX4-1 and COX5A CIV subunits and, when overexpressed, suppresses the CIV biogenesis defect of HIGD2A-KO cells. We conclude that HIGD1A and HIGD2A have both independent and overlapping functions in the biogenesis of respiratory complexes and supercomplexes. Our data illuminate the existence of multiple pathways to assemble these structures by dynamic HIGD-mediated CIV biogenesis, potentially to adapt to changing environmental and nutritional conditions.
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12
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Erdogan B, Bearce EA, Lowery LA. Live Imaging of Cytoskeletal Dynamics in Embryonic Xenopus laevis Growth Cones and Neural Crest Cells. Cold Spring Harb Protoc 2021; 2021:pdb.prot104463. [PMID: 33272974 DOI: 10.1101/pdb.prot104463] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The cytoskeleton is a dynamic, fundamental network that not only provides mechanical strength to maintain a cell's shape but also controls critical events like cell division, polarity, and movement. Thus, how the cytoskeleton is organized and dynamically regulated is critical to our understanding of countless processes. Live imaging of fluorophore-tagged cytoskeletal proteins allows us to monitor the dynamic nature of cytoskeleton components in embryonic cells. Here, we describe a protocol to monitor and analyze cytoskeletal dynamics in primary embryonic neuronal growth cones and neural crest cells obtained from Xenopus laevis embryos.
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Affiliation(s)
- Burcu Erdogan
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Elizabeth A Bearce
- Institute of Molecular Biology, Department of Biology, University of Oregon, Eugene, Oregon 97403, USA
| | - Laura Anne Lowery
- Boston University School of Medicine, Boston Medical Center, Boston, Massachusetts 02118, USA
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13
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Timón-Gómez A, Bartley-Dier EL, Fontanesi F, Barrientos A. HIGD-Driven Regulation of Cytochrome c Oxidase Biogenesis and Function. Cells 2020; 9:cells9122620. [PMID: 33291261 PMCID: PMC7762129 DOI: 10.3390/cells9122620] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 12/02/2020] [Accepted: 12/04/2020] [Indexed: 12/24/2022] Open
Abstract
The biogenesis and function of eukaryotic cytochrome c oxidase or mitochondrial respiratory chain complex IV (CIV) undergo several levels of regulation to adapt to changing environmental conditions. Adaptation to hypoxia and oxidative stress involves CIV subunit isoform switch, changes in phosphorylation status, and modulation of CIV assembly and enzymatic activity by interacting factors. The latter include the Hypoxia Inducible Gene Domain (HIGD) family yeast respiratory supercomplex factors 1 and 2 (Rcf1 and Rcf2) and two mammalian homologs of Rcf1, the proteins HIGD1A and HIGD2A. Whereas Rcf1 and Rcf2 are expressed constitutively, expression of HIGD1A and HIGD2A is induced under stress conditions, such as hypoxia and/or low glucose levels. In both systems, the HIGD proteins localize in the mitochondrial inner membrane and play a role in the biogenesis of CIV as a free unit or as part as respiratory supercomplexes. Notably, they remain bound to assembled CIV and, by modulating its activity, regulate cellular respiration. Here, we will describe the current knowledge regarding the specific and overlapping roles of the several HIGD proteins in physiological and stress conditions.
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Affiliation(s)
- Alba Timón-Gómez
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL 33136, USA;
| | - Emma L. Bartley-Dier
- Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, Miami, FL 33136, USA; (E.L.B.-D.); (F.F.)
| | - Flavia Fontanesi
- Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, Miami, FL 33136, USA; (E.L.B.-D.); (F.F.)
| | - Antoni Barrientos
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL 33136, USA;
- Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, Miami, FL 33136, USA; (E.L.B.-D.); (F.F.)
- Correspondence:
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14
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Functions of Cytochrome c oxidase Assembly Factors. Int J Mol Sci 2020; 21:ijms21197254. [PMID: 33008142 PMCID: PMC7582755 DOI: 10.3390/ijms21197254] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Accepted: 09/23/2020] [Indexed: 12/22/2022] Open
Abstract
Cytochrome c oxidase is the terminal complex of eukaryotic oxidative phosphorylation in mitochondria. This process couples the reduction of electron carriers during metabolism to the reduction of molecular oxygen to water and translocation of protons from the internal mitochondrial matrix to the inter-membrane space. The electrochemical gradient formed is used to generate chemical energy in the form of adenosine triphosphate to power vital cellular processes. Cytochrome c oxidase and most oxidative phosphorylation complexes are the product of the nuclear and mitochondrial genomes. This poses a series of topological and temporal steps that must be completed to ensure efficient assembly of the functional enzyme. Many assembly factors have evolved to perform these steps for insertion of protein into the inner mitochondrial membrane, maturation of the polypeptide, incorporation of co-factors and prosthetic groups and to regulate this process. Much of the information about each of these assembly factors has been gleaned from use of the single cell eukaryote Saccharomyces cerevisiae and also mutations responsible for human disease. This review will focus on the assembly factors of cytochrome c oxidase to highlight some of the outstanding questions in the assembly of this vital enzyme complex.
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15
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Dawitz H, Schäfer J, Schaart JM, Magits W, Brzezinski P, Ott M. Rcf1 Modulates Cytochrome c Oxidase Activity Especially Under Energy-Demanding Conditions. Front Physiol 2020; 10:1555. [PMID: 32009973 PMCID: PMC6971206 DOI: 10.3389/fphys.2019.01555] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Accepted: 12/10/2019] [Indexed: 12/17/2022] Open
Abstract
The mitochondrial respiratory chain is assembled into supercomplexes. Previously, two respiratory supercomplex-associated proteins, Rcf1 and Rcf2, were identified in Saccharomyces cerevisiae, which were initially suggested to mediate supercomplex formation. Recent evidence suggests that these factors instead are involved in cytochrome c oxidase biogenesis. We demonstrate here that Rcf1 mediates proper function of cytochrome c oxidase, while binding of Rcf2 results in a decrease of cytochrome c oxidase activity. Chemical crosslink experiments demonstrate that the conserved Hig-domain as well as the fungi specific C-terminus of Rcf1 are involved in molecular interactions with the cytochrome c oxidase subunit Cox3. We propose that Rcf1 modulates cytochrome c oxidase activity by direct binding to the oxidase to trigger changes in subunit Cox1, which harbors the catalytic site. Additionally, Rcf1 interaction with cytochrome c oxidase in the supercomplexes increases under respiratory conditions. These observations indicate that Rcf1 could enable the tuning of the respiratory chain depending on metabolic needs or repair damages at the catalytic site.
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Affiliation(s)
- Hannah Dawitz
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Jacob Schäfer
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Judith M Schaart
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Wout Magits
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Peter Brzezinski
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Martin Ott
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
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16
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Barros MH, McStay GP. Modular biogenesis of mitochondrial respiratory complexes. Mitochondrion 2019; 50:94-114. [PMID: 31669617 DOI: 10.1016/j.mito.2019.10.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 09/04/2019] [Accepted: 10/10/2019] [Indexed: 11/29/2022]
Abstract
Mitochondrial function relies on the activity of oxidative phosphorylation to synthesise ATP and generate an electrochemical gradient across the inner mitochondrial membrane. These coupled processes are mediated by five multi-subunit complexes that reside in this inner membrane. These complexes are the product of both nuclear and mitochondrial gene products. Defects in the function or assembly of these complexes can lead to mitochondrial diseases due to deficits in energy production and mitochondrial functions. Appropriate biogenesis and function are mediated by a complex number of assembly factors that promote maturation of specific complex subunits to form the active oxidative phosphorylation complex. The understanding of the biogenesis of each complex has been informed by studies in both simple eukaryotes such as Saccharomyces cerevisiae and human patients with mitochondrial diseases. These studies reveal each complex assembles through a pathway using specific subunits and assembly factors to form kinetically distinct but related assembly modules. The current understanding of these complexes has embraced the revolutions in genomics and proteomics to further our knowledge on the impact of mitochondrial biology in genetics, medicine, and evolution.
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Affiliation(s)
- Mario H Barros
- Departamento de Microbiologia - Instituto de Ciências Biomédicas, Universidade de São Paulo, Brazil.
| | - Gavin P McStay
- Department of Biological Sciences, Staffordshire University, Stoke-on-Trent, United Kingdom.
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17
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Chicherin IV, Zinina VV, Levitskiy SA, Serebryakova MV, Kamenski PA. Aim23p Interacts with the Yeast Mitochondrial Ribosomal Small Subunit. BIOCHEMISTRY (MOSCOW) 2019; 84:40-46. [DOI: 10.1134/s000629791901005x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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18
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Strogolova V, Hoang NH, Hosler J, Stuart RA. The yeast mitochondrial proteins Rcf1 and Rcf2 support the enzymology of the cytochrome c oxidase complex and generation of the proton motive force. J Biol Chem 2019; 294:4867-4877. [PMID: 30683696 DOI: 10.1074/jbc.ra118.006888] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Revised: 01/22/2019] [Indexed: 11/06/2022] Open
Abstract
The yeast mitochondrial proteins Rcf1 and Rcf2 are associated with a subpopulation of the cytochrome bc 1-cytochrome c oxidase supercomplex and have been proposed to play a role in the assembly and/or modulation of the activity of the cytochrome c oxidase (complex IV, CIV). Yeast mutants deficient in either Rcf1 or Rcf2 proteins can use aerobic respiration-based metabolism for growth, but the absence of both proteins results in a strong growth defect. In this study, using assorted biochemical and biophysical analyses of Rcf1/Rcf2 single and double null-mutant yeast cells and mitochondria, we further explored how Rcf1 and Rcf2 support aerobic respiration and growth. We show that the absence of Rcf1 physically reduces the levels of CIV and diminishes the ability of the CIV that is present to maintain a normal mitochondrial proton motive force (PMF). Although the absence of Rcf2 did not noticeably affect the physical content of CIV, the PMF generated by CIV was also lower than normal. Our results indicate that the detrimental effects of the absence of Rcf1 and Rcf2 proteins on the CIV complex are distinct in terms of CIV assembly/accumulation and additive in terms of the ability of CIV to generate PMF. Thus, the combined absence of Rcf1 and Rcf2 alters both CIV physiology and assembly. We conclude that the slow aerobic growth of the Rcf1/Rcf2 double null mutant results from diminished generation of mitochondrial PMF by CIV and limits the level of CIV activity required for maintenance of the PMF and growth under aerobic conditions.
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Affiliation(s)
- Vera Strogolova
- From the Department of Biological Sciences, Marquette University, Milwaukee, Wisconsin 53233 and
| | - Ngoc H Hoang
- the Department of Cell and Molecular Biology, University of Mississippi Medical Center, Jackson, Mississippi 39216
| | - Jonathan Hosler
- the Department of Cell and Molecular Biology, University of Mississippi Medical Center, Jackson, Mississippi 39216
| | - Rosemary A Stuart
- From the Department of Biological Sciences, Marquette University, Milwaukee, Wisconsin 53233 and
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19
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Ogunbona OB, Baile MG, Claypool SM. Cardiomyopathy-associated mutation in the ADP/ATP carrier reveals translation-dependent regulation of cytochrome c oxidase activity. Mol Biol Cell 2018; 29:1449-1464. [PMID: 29688796 PMCID: PMC6014099 DOI: 10.1091/mbc.e17-12-0700] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Revised: 03/16/2018] [Accepted: 04/18/2018] [Indexed: 01/07/2023] Open
Abstract
How the absence of the major mitochondrial ADP/ATP carrier in yeast, Aac2p, results in a specific defect in cytochrome c oxidase (COX; complex IV) activity is a long-standing mystery. Aac2p physically associates with respiratory supercomplexes, which include complex IV, raising the possibility that its activity is dependent on its association with Aac2p. Here, we have leveraged a transport-dead pathogenic AAC2 point mutant to determine the basis for the reduced COX activity in the absence of Aac2p. The steady-state levels of complex IV subunits encoded by the mitochondrial genome are significantly reduced in the absence of Aac2p function, whether its association with respiratory supercomplexes is preserved or not. This diminution in COX amounts is not caused by a reduction in the mitochondrial genome copy number or the steady-state level of its transcripts, and does not reflect a defect in complex IV assembly. Instead, the absence of Aac2p activity, genetically or pharmacologically, results in an aberrant pattern of mitochondrial translation. Interestingly, compared with the complete absence of Aac2p, the complex IV-related defects are greater in mitochondria expressing the transport-inactive Aac2p mutant. Our results highlight a critical role for Aac2p transport in mitochondrial translation whose disturbance uniquely impacts cytochrome c oxidase.
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Affiliation(s)
- Oluwaseun B. Ogunbona
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD 21205-2185
| | | | - Steven M. Claypool
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD 21205-2185
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20
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García-Guerrero AE, Camacho-Villasana Y, Zamudio-Ochoa A, Winge DR, Pérez-Martínez X. Cbp3 and Cbp6 are dispensable for synthesis regulation of cytochrome b in yeast mitochondria. J Biol Chem 2018; 293:5585-5599. [PMID: 29475949 DOI: 10.1074/jbc.ra117.000547] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Revised: 02/08/2018] [Indexed: 11/06/2022] Open
Abstract
Cytochrome b (Cytb) is the only mitochondrial encoded subunit from the bc1 complex. Cbp3 and Cbp6 are chaperones necessary for translation of the COB mRNA and Cytb hemylation. Here we demonstrate that their role in translation is dispensable in some laboratory strains, whereas their role in Cytb hemylation seems to be universally conserved. BY4742 yeast requires Cbp3 and Cbp6 for efficient COB mRNA translation, whereas the D273-10b strain synthesizes Cytb at wildtype levels in the absence of Cbp3 and Cbp6. Steady-state levels of Cytb are close to wildtype in mutant D273-10b cells, and Cytb forms non-functional, supercomplex-like species with cytochrome c oxidase, in which at least core 1, cytochrome c1, and Rieske iron-sulfur subunits are present. We demonstrated that Cbp3 interacts with the mitochondrial ribosome and with the COB mRNA in both BY4742 and D273-10b strains. The polymorphism(s) causing the differential function of Cbp3, Cbp6, and the assembly feedback regulation of Cytb synthesis is of nuclear origin rather than mitochondrial, and Smt1, a COB mRNA-binding protein, does not seem to be involved in the observed differential phenotype. Our results indicate that the essential role of Cbp3 and Cbp6 is to assist Cytb hemylation and demonstrate that in the absence of heme b, Cytb can form non-functional supercomplexes with cytochrome c oxidase. Our observations support that an additional protein or proteins are involved in Cytb synthesis in some yeast strains.
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Affiliation(s)
- Aldo E García-Guerrero
- From the Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Circuito Exterior s/n Ciudad Universitaria, Coyoacán, 04510 Mexico City, Mexico and
| | - Yolanda Camacho-Villasana
- From the Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Circuito Exterior s/n Ciudad Universitaria, Coyoacán, 04510 Mexico City, Mexico and
| | - Angélica Zamudio-Ochoa
- From the Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Circuito Exterior s/n Ciudad Universitaria, Coyoacán, 04510 Mexico City, Mexico and
| | - Dennis R Winge
- the Department of Medicine and Biochemistry, University of Utah Health Sciences Center, Salt Lake, Utah 84132
| | - Xochitl Pérez-Martínez
- From the Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Circuito Exterior s/n Ciudad Universitaria, Coyoacán, 04510 Mexico City, Mexico and
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21
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Jett KA, Leary SC. Building the Cu A site of cytochrome c oxidase: A complicated, redox-dependent process driven by a surprisingly large complement of accessory proteins. J Biol Chem 2017; 293:4644-4652. [PMID: 28972150 DOI: 10.1074/jbc.r117.816132] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cytochrome c oxidase (COX) was initially purified more than 70 years ago. A tremendous amount of insight into its structure and function has since been gleaned from biochemical, biophysical, genetic, and molecular studies. As a result, we now appreciate that COX relies on its redox-active metal centers (heme a and a3, CuA and CuB) to reduce oxygen and pump protons in a reaction essential for most eukaryotic life. Questions persist, however, about how individual structural subunits are assembled into a functional holoenzyme. Here, we focus on what is known and what remains to be learned about the accessory proteins that facilitate CuA site maturation.
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Affiliation(s)
- Kimberly A Jett
- Department of Biochemistry, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5, Canada
| | - Scot C Leary
- Department of Biochemistry, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5, Canada.
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22
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García-Villegas R, Camacho-Villasana Y, Shingú-Vázquez MÁ, Cabrera-Orefice A, Uribe-Carvajal S, Fox TD, Pérez-Martínez X. The Cox1 C-terminal domain is a central regulator of cytochrome c oxidase biogenesis in yeast mitochondria. J Biol Chem 2017; 292:10912-10925. [PMID: 28490636 DOI: 10.1074/jbc.m116.773077] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Revised: 05/09/2017] [Indexed: 12/21/2022] Open
Abstract
Cytochrome c oxidase (CcO) is the last electron acceptor in the respiratory chain. The CcO core is formed by mitochondrial DNA-encoded Cox1, Cox2, and Cox3 subunits. Cox1 synthesis is highly regulated; for example, if CcO assembly is blocked, Cox1 synthesis decreases. Mss51 activates translation of COX1 mRNA and interacts with Cox1 protein in high-molecular-weight complexes (COA complexes) to form the Cox1 intermediary assembly module. Thus, Mss51 coordinates both Cox1 synthesis and assembly. We previously reported that the last 15 residues of the Cox1 C terminus regulate Cox1 synthesis by modulating an interaction of Mss51 with Cox14, another component of the COA complexes. Here, using site-directed mutagenesis of the mitochondrial COX1 gene from Saccharomyces cerevisiae, we demonstrate that mutations P521A/P522A and V524E disrupt the regulatory role of the Cox1 C terminus. These mutations, as well as C terminus deletion (Cox1ΔC15), reduced binding of Mss51 and Cox14 to COA complexes. Mss51 was enriched in a translationally active form that maintains full Cox1 synthesis even if CcO assembly is blocked in these mutants. Moreover, Cox1ΔC15, but not Cox1-P521A/P522A and Cox1-V524E, promoted formation of aberrant supercomplexes in CcO assembly mutants lacking Cox2 or Cox4 subunits. The aberrant supercomplex formation depended on the presence of cytochrome b and Cox3, supporting the idea that supercomplex assembly factors associate with Cox3 and demonstrating that supercomplexes can be formed even if CcO is inactive and not fully assembled. Our results indicate that the Cox1 C-terminal end is a key regulator of CcO biogenesis and that it is important for supercomplex formation/stability.
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Affiliation(s)
- Rodolfo García-Villegas
- From the Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, 04510, Mexico
| | - Yolanda Camacho-Villasana
- From the Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, 04510, Mexico
| | - Miguel Ángel Shingú-Vázquez
- the Australian Research Council Centre of Excellence for Advanced Molecular Imaging, Monash University, Clayton, Victoria 3800, Australia
| | - Alfredo Cabrera-Orefice
- the Radboud Center for Mitochondrial Medicine, Radboud University Medical Center, 6500 HB Nijmegen, The Netherlands, and
| | - Salvador Uribe-Carvajal
- From the Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, 04510, Mexico
| | - Thomas D Fox
- the Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14853
| | - Xochitl Pérez-Martínez
- From the Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, 04510, Mexico,
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23
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MR-1S Interacts with PET100 and PET117 in Module-Based Assembly of Human Cytochrome c Oxidase. Cell Rep 2017; 18:1727-1738. [DOI: 10.1016/j.celrep.2017.01.044] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Revised: 12/06/2016] [Accepted: 01/19/2017] [Indexed: 01/04/2023] Open
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24
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Dela Cruz R, Jeong MY, Winge DR. Cox1 mutation abrogates need for Cox23 in cytochrome c oxidase biogenesis. MICROBIAL CELL 2016; 3:275-284. [PMID: 28357365 PMCID: PMC5354592 DOI: 10.15698/mic2016.07.511] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Cox23 is a known conserved assembly factor for cytochrome c
oxidase, although its role in cytochrome c oxidase (CcO)
biogenesis remains unresolved. To gain additional insights into its role, we
isolated spontaneous suppressors of the respiratory growth defect in
cox23∆ yeast cells. We recovered independent colonies that
propagated on glycerol/lactate medium for cox23∆ cells at 37°C.
We mapped these mutations to the mitochondrial genome and specifically to
COX1 yielding an I101F substitution. The
I101F Cox1 allele is a gain-of-function mutation enabling yeast
to respire in the absence of Cox23. CcO subunit steady-state levels were
restored with the I101F Cox1 suppressor mutation and oxygen
consumption and CcO activity were likewise restored. Cells harboring the
mitochondrial genome encoding I101F Cox1 were used to delete genes
for other CcO assembly factors to test the specificity of the Cox1 mutation as a
suppressor of cox23∆ cells. The Cox1 mutant allele fails to
support respiratory growth in yeast lacking Cox17, Cox19, Coa1, Coa2, Cox14 or
Shy1, demonstrating its specific suppressor activity for cox23∆
cells.
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Affiliation(s)
- Richard Dela Cruz
- University of Utah Health Sciences Center, Departments of Medicine and Biochemistry, Salt Lake City, Utah 84132, USA. ; Present address: Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA
| | - Mi-Young Jeong
- University of Utah Health Sciences Center, Departments of Medicine and Biochemistry, Salt Lake City, Utah 84132, USA
| | - Dennis R Winge
- University of Utah Health Sciences Center, Departments of Medicine and Biochemistry, Salt Lake City, Utah 84132, USA
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25
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Mayorga JP, Camacho-Villasana Y, Shingú-Vázquez M, García-Villegas R, Zamudio-Ochoa A, García-Guerrero AE, Hernández G, Pérez-Martínez X. A Novel Function of Pet54 in Regulation of Cox1 Synthesis in Saccharomyces cerevisiae Mitochondria. J Biol Chem 2016; 291:9343-55. [PMID: 26929411 DOI: 10.1074/jbc.m116.721985] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Indexed: 12/21/2022] Open
Abstract
Cytochrome c oxidase assembly requires the synthesis of the mitochondria-encoded core subunits, Cox1, Cox2, and Cox3. In yeast, Pet54 protein is required to activate translation of the COX3 mRNA and to process the aI5β intron on the COX1 transcript. Here we report a third, novel function of Pet54 on Cox1 synthesis. We observed that Pet54 is necessary to achieve an efficient Cox1 synthesis. Translation of the COX1 mRNA is coupled to the assembly of cytochrome c oxidase by a mechanism that involves Mss51. This protein activates translation of the COX1 mRNA by acting on the COX1 5'-UTR, and, in addition, it interacts with the newly synthesized Cox1 protein in high molecular weight complexes that include the factors Coa3 and Cox14. Deletion of Pet54 decreased Cox1 synthesis, and, in contrast to what is commonly observed for other assembly mutants, double deletion of cox14 or coa3 did not recover Cox1 synthesis. Our results show that Pet54 is a positive regulator of Cox1 synthesis that renders Mss51 competent as a translational activator of the COX1 mRNA and that this role is independent of the assembly feedback regulatory loop of Cox1 synthesis. Pet54 may play a role in Mss51 hemylation/conformational change necessary for translational activity. Moreover, Pet54 physically interacts with the COX1 mRNA, and this binding was independent of the presence of Mss51.
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Affiliation(s)
- Juan Pablo Mayorga
- From the Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City 04510, Mexico
| | - Yolanda Camacho-Villasana
- From the Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City 04510, Mexico
| | - Miguel Shingú-Vázquez
- the Department of Biochemistry and Molecular Biology, School of Biomedical Sciences Monash University, Clayton, Victoria 3800, Australia, and
| | - Rodolfo García-Villegas
- From the Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City 04510, Mexico
| | - Angélica Zamudio-Ochoa
- From the Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City 04510, Mexico
| | - Aldo E García-Guerrero
- From the Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City 04510, Mexico
| | - Greco Hernández
- the Division of Basic Research, National Institute of Cancer (INCan), Mexico City 14080, Mexico
| | - Xochitl Pérez-Martínez
- From the Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City 04510, Mexico,
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26
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Ghosh A, Pratt AT, Soma S, Theriault SG, Griffin AT, Trivedi PP, Gohil VM. Mitochondrial disease genes COA6, COX6B and SCO2 have overlapping roles in COX2 biogenesis. Hum Mol Genet 2015; 25:660-71. [PMID: 26669719 DOI: 10.1093/hmg/ddv503] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Accepted: 12/07/2015] [Indexed: 01/19/2023] Open
Abstract
Biogenesis of cytochrome c oxidase (CcO), the terminal enzyme of the mitochondrial respiratory chain, is a complex process facilitated by several assembly factors. Pathogenic mutations were recently reported in one such assembly factor, COA6, and our previous work linked Coa6 function to mitochondrial copper metabolism and expression of Cox2, a copper-containing subunit of CcO. However, the precise role of Coa6 in Cox2 biogenesis remained unknown. Here we show that yeast Coa6 is an orthologue of human COA6, and like Cox2, is regulated by copper availability, further implicating it in copper delivery to Cox2. In order to place Coa6 in the Cox2 copper delivery pathway, we performed a comprehensive genetic epistasis analysis in the yeast Saccharomyces cerevisiae and found that simultaneous deletion of Coa6 and Sco2, a mitochondrial copper metallochaperone, or Coa6 and Cox12/COX6B, a structural subunit of CcO, completely abrogates Cox2 biogenesis. Unlike Coa6 deficient cells, copper supplementation fails to rescue Cox2 levels of these double mutants. Overexpression of Cox12 or Sco proteins partially rescues the coa6Δ phenotype, suggesting their overlapping but non-redundant roles in copper delivery to Cox2. These genetic data are strongly corroborated by biochemical studies demonstrating physical interactions between Coa6, Cox2, Cox12 and Sco proteins. Furthermore, we show that patient mutations in Coa6 disrupt Coa6-Cox2 interaction, providing the biochemical basis for disease pathogenesis. Taken together, these results place COA6 in the copper delivery pathway to CcO and, surprisingly, link it to a previously unidentified function of CcO subunit Cox12 in Cox2 biogenesis.
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Affiliation(s)
- Alok Ghosh
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
| | - Anthony T Pratt
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
| | - Shivatheja Soma
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
| | - Sarah G Theriault
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
| | - Aaron T Griffin
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
| | - Prachi P Trivedi
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
| | - Vishal M Gohil
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
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27
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Mansilla N, Garcia L, Gonzalez DH, Welchen E. AtCOX10, a protein involved in haem o synthesis during cytochrome c oxidase biogenesis, is essential for plant embryogenesis and modulates the progression of senescence. JOURNAL OF EXPERIMENTAL BOTANY 2015; 66:6761-75. [PMID: 26246612 DOI: 10.1093/jxb/erv381] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Cytochrome c oxidase (CcO) biogenesis requires several accessory proteins implicated, among other processes, in copper and haem a insertion. In yeast, the farnesyltransferase Cox10p that catalyses the conversion of haem b to haem o is the limiting factor in haem a biosynthesis and is essential for haem a insertion in CcO. In this work, we characterized AtCOX10, a putative Cox10p homologue from Arabidopsis thaliana. AtCOX10 was localized in mitochondria and was able to restore growth of a yeast Δcox10 null mutant on non-fermentable carbon sources, suggesting that it also participates in haem o synthesis. Plants with T-DNA insertions in the coding region of both copies of AtCOX10 could not be recovered, and heterozygous mutant plants showed seeds with embryos arrested at early developmental stages that lacked CcO activity. Heterozygous mutant plants exhibited lower levels of CcO activity and cyanide-sensitive respiration but normal levels of total respiration at the expense of an increase in alternative respiration. AtCOX10 seems to be implicated in the onset and progression of senescence, since heterozygous mutant plants showed a faster decrease in chlorophyll content and photosynthetic performance than wild-type plants after natural and dark-induced senescence. Furthermore, complementation of mutants by expressing AtCOX10 under its own promoter allowed us to obtain plants with T-DNA insertions in both AtCOX10 copies, which showed phenotypic characteristics comparable to those of wild type. Our results highlight the relevance of haem o synthesis in plants and suggest that this process is a limiting factor that influences CcO activity levels, mitochondrial respiration, and plant senescence.
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Affiliation(s)
- Natanael Mansilla
- Instituto de Agrobiotecnología del Litoral (CONICET-UNL), Cátedra de Biología Celular y Molecular, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, Centro Científico Tecnológico Santa Fe - Colectora Ruta Nacional Nº 168 Km 0, Paraje El Pozo, 3000 Santa Fe, Argentina
| | - Lucila Garcia
- Instituto de Agrobiotecnología del Litoral (CONICET-UNL), Cátedra de Biología Celular y Molecular, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, Centro Científico Tecnológico Santa Fe - Colectora Ruta Nacional Nº 168 Km 0, Paraje El Pozo, 3000 Santa Fe, Argentina
| | - Daniel H Gonzalez
- Instituto de Agrobiotecnología del Litoral (CONICET-UNL), Cátedra de Biología Celular y Molecular, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, Centro Científico Tecnológico Santa Fe - Colectora Ruta Nacional Nº 168 Km 0, Paraje El Pozo, 3000 Santa Fe, Argentina
| | - Elina Welchen
- Instituto de Agrobiotecnología del Litoral (CONICET-UNL), Cátedra de Biología Celular y Molecular, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, Centro Científico Tecnológico Santa Fe - Colectora Ruta Nacional Nº 168 Km 0, Paraje El Pozo, 3000 Santa Fe, Argentina
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28
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Su CH, McStay GP, Tzagoloff A. Assembly of the rotor component of yeast mitochondrial ATP synthase is enhanced when Atp9p is supplied by Atp9p-Cox6p complexes. J Biol Chem 2014; 289:31605-16. [PMID: 25253699 DOI: 10.1074/jbc.m114.602706] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Atp9p ring is one of several assembly modules of yeast mitochondrial ATP synthase. The ring, composed of 10 copies of Atp9p, is part of the rotor that couples proton translocation to synthesis or hydrolysis of ATP. We present evidence that before its assembly with other ATP synthase modules, most of Atp9p is present in at least three complexes with masses of 200-400 kDa that co-immunopurify with Cox6p. Pulse-labeling analysis disclosed a time-dependent reduction of radiolabeled Atp9p in the complexes and an increase of Atp9p in the ring form of wild type yeast and of mss51, pet111, and pet494 mutants lacking Cox1p, Cox2p, and Cox3p, respectively. Ring formation was not significantly different from wild type in an mss51 or atp10 mutant. The atp10 mutation blocks the interaction of the Atp9p ring with other modules of the ATP synthase. In contrast, ring formation was reduced in a cox6 mutant, consistent with a role of Cox6p in oligomerization of Atp9p. Cox6p involvement in ATP synthase assembly is also supported by studies showing that ring formation in cells adapting from fermentative to aerobic growth was less efficient in mitochondria of the cox6 mutant than the parental respiratory-competent strain or a cox4 mutant. We speculate that the constitutive and Cox6p-independent rate of Atp9p oligomerization may be sufficient to produce the level of ATP synthase needed for maintaining a membrane potential but limiting for optimal oxidative phosphorylation.
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Affiliation(s)
- Chen-Hsien Su
- From the Department of Biological Sciences, Columbia University, New York, New York 10128 and
| | - Gavin P McStay
- Department of Life Sciences, New York Institute of Technology, Old Westbury, New York 11568
| | - Alexander Tzagoloff
- From the Department of Biological Sciences, Columbia University, New York, New York 10128 and
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