1
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Hubble KA, Henry MF. DPC29 promotes post-initiation mitochondrial translation in Saccharomyces cerevisiae. Nucleic Acids Res 2023; 51:1260-1276. [PMID: 36620885 PMCID: PMC9943650 DOI: 10.1093/nar/gkac1229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Revised: 12/07/2022] [Accepted: 12/09/2022] [Indexed: 01/10/2023] Open
Abstract
Mitochondrial ribosomes synthesize essential components of the oxidative phosphorylation (OXPHOS) system in a tightly regulated process. In the yeast Saccharomyces cerevisiae, mitochondrial mRNAs require specific translational activators, which orchestrate protein synthesis by recognition of their target gene's 5'-untranslated region (UTR). Most of these yeast genes lack orthologues in mammals, and only one such gene-specific translational activator has been proposed in humans-TACO1. The mechanism by which TACO1 acts is unclear because mammalian mitochondrial mRNAs do not have significant 5'-UTRs, and therefore must promote translation by alternative mechanisms. In this study, we examined the role of the TACO1 orthologue in yeast. We found this 29 kDa protein to be a general mitochondrial translation factor, Dpc29, rather than a COX1-specific translational activator. Its activity was necessary for the optimal expression of OXPHOS mtDNA reporters, and mutations within the mitoribosomal large subunit protein gene MRP7 produced a global reduction of mitochondrial translation in dpc29Δ cells, indicative of a general mitochondrial translation factor. Northern-based mitoribosome profiling of dpc29Δ cells showed higher footprint frequencies at the 3' ends of mRNAs, suggesting a role in translation post-initiation. Additionally, human TACO1 expressed at native levels rescued defects in dpc29Δ yeast strains, suggesting that the two proteins perform highly conserved functions.
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Affiliation(s)
- Kyle A Hubble
- Department of Molecular Biology, Rowan University School of Osteopathic Medicine, Stratford, NJ 08084, USA,Graduate School of Biomedical Sciences, Rowan University, Stratford, NJ 08084, USA
| | - Michael F Henry
- To whom correspondence should be addressed. Tel: +1 856 566 6970; Fax: +1 856 566 6291; E-mail:
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2
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Overexpression of MRX9 impairs processing of RNAs encoding mitochondrial oxidative phosphorylation factors COB and COX1 in yeast. J Biol Chem 2022; 298:102214. [PMID: 35779633 PMCID: PMC9307953 DOI: 10.1016/j.jbc.2022.102214] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 06/20/2022] [Accepted: 06/21/2022] [Indexed: 11/24/2022] Open
Abstract
Mitochondrial translation is a highly regulated process, and newly synthesized mitochondrial products must first associate with several nuclear-encoded auxiliary factors to form oxidative phosphorylation complexes. The output of mitochondrial products should therefore be in stoichiometric equilibrium with the nuclear-encoded products to prevent unnecessary energy expense or the accumulation of pro-oxidant assembly modules. In the mitochondrial DNA of Saccharomyces cerevisiae, COX1 encodes subunit 1 of the cytochrome c oxidase and COB the central core of the cytochrome bc1 electron transfer complex; however, factors regulating the expression of these mitochondrial products are not completely described. Here, we identified Mrx9p as a new factor that controls COX1 and COB expression. We isolated MRX9 in a screen for mitochondrial factors that cause poor accumulation of newly synthesized Cox1p and compromised transition to the respiratory metabolism. Northern analyses indicated lower levels of COX1 and COB mature mRNAs accompanied by an accumulation of unprocessed transcripts in the presence of excess Mrx9p. In a strain devoid of mitochondrial introns, MRX9 overexpression did not affect COX1 and COB translation or respiratory adaptation, implying Mrx9p regulates processing of COX1 and COB RNAs. In addition, we found Mrx9p was localized in the mitochondrial inner membrane, facing the matrix, as a portion of it cosedimented with mitoribosome subunits and its removal or overexpression altered Mss51p sedimentation. Finally, we showed accumulation of newly synthesized Cox1p in the absence of Mrx9p was diminished in cox14 null mutants. Taken together, these data indicate a regulatory role of Mrx9p in COX1 RNA processing.
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3
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Anderson JM, Box JM, Stuart RA. The mitospecific domain of Mrp7 (bL27) supports mitochondrial translation during fermentation and is required for effective adaptation to respiration. Mol Biol Cell 2021; 33:ar7. [PMID: 34731012 PMCID: PMC8886811 DOI: 10.1091/mbc.e21-07-0370] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
We demonstrate here that mitoribosomal protein synthesis, responsible for the synthesis of oxidative phosphorylation (OXPHOS) subunits encoded by mitochondrial genome, occurs at high levels during glycolysis fermentation and in a manner uncoupled from OXPHOS complex assembly regulation. Furthermore, we provide evidence that the mitospecific domain of Mrp7 (bL27), a mitoribosomal component, is required to maintain mitochondrial protein synthesis during fermentation, but is not required under respiration growth conditions. Maintaining mitotranslation under high glucose fermentation conditions also involves Mam33 (p32/gC1qR homolog), a binding partner of Mrp7's mitospecific domain, and together they confer a competitive advantage for a cell's ability to adapt to respiration-based metabolism when glucose becomes limiting. Furthermore, our findings support that the mitoribosome, and specifically the central protuberance (CP) region, may be differentially regulated and/or assembled, under the different metabolic conditions of fermentation and respiration. Based on our findings, we propose the purpose of mitotranslation is not limited to the assembly of OXPHOS complexes, but also plays a role in mitochondrial signaling critical for switching cellular metabolism from a glycolysis- to a respiratory-based state.
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Affiliation(s)
| | - Jodie M Box
- Dept. of Biological Sciences, Marquette University, Milwaukee, WI, USA
| | - Rosemary A Stuart
- Dept. of Biological Sciences, Marquette University, Milwaukee, WI, USA
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4
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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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5
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Mays JN, Camacho-Villasana Y, Garcia-Villegas R, Perez-Martinez X, Barrientos A, Fontanesi F. The mitoribosome-specific protein mS38 is preferentially required for synthesis of cytochrome c oxidase subunits. Nucleic Acids Res 2019; 47:5746-5760. [PMID: 30968120 PMCID: PMC6582356 DOI: 10.1093/nar/gkz266] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Revised: 03/26/2019] [Accepted: 04/02/2019] [Indexed: 12/20/2022] Open
Abstract
Message-specific translational regulation mechanisms shape the biogenesis of multimeric oxidative phosphorylation (OXPHOS) enzyme in mitochondria from the yeast Saccharomyces cerevisiae. These mechanisms, driven mainly by the action of mRNA-specific translational activators, help to coordinate synthesis of OXPHOS catalytic subunits by the mitoribosomes with both the import of their nucleus-encoded partners and their assembly to form the holocomplexes. However, little is known regarding the role that the mitoribosome itself may play in mRNA-specific translational regulation. Here, we show that the mitoribosome small subunit protein Cox24/mS38, known to be necessary for mitoribosome-specific intersubunit bridge formation and 15S rRNA H44 stabilization, is required for efficient mitoribogenesis. Consequently, mS38 is necessary to sustain the overall mitochondrial protein synthesis rate, despite an adaptive ∼2-fold increase in mitoribosome abundance in mS38-deleted cells. Additionally, the absence of mS38 preferentially disturbs translation initiation of COX1, COX2, and COX3 mRNAs, without affecting the levels of mRNA-specific translational activators. We propose that mS38 confers the mitochondrial ribosome an intrinsic capacity of translational regulation, probably acquired during evolution from bacterial ribosomes to facilitate the translation of mitochondrial mRNAs, which lack typical anti-Shine-Dalgarno sequences.
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Affiliation(s)
- Jeffri-Noelle Mays
- Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Yolanda Camacho-Villasana
- Departamento de Genetica Molecular, Instituto de Fisiologiía Celular, Universidad Nacional Autonoma de Mexico, Mexico City 04510, Mexico
| | - Rodolfo Garcia-Villegas
- Departamento de Genetica Molecular, Instituto de Fisiologiía Celular, Universidad Nacional Autonoma de Mexico, Mexico City 04510, Mexico
| | - Xochitl Perez-Martinez
- Departamento de Genetica Molecular, Instituto de Fisiologiía Celular, Universidad Nacional Autonoma de Mexico, Mexico City 04510, Mexico
| | - Antoni Barrientos
- Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, Miami, FL 33136, USA.,Department of Neurology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Flavia Fontanesi
- Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
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6
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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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7
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Mitochondrial respirasome works as a single unit and the cross-talk between complexes I, III 2 and IV stimulates NADH dehydrogenase activity. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2019; 1860:618-627. [PMID: 31251900 DOI: 10.1016/j.bbabio.2019.06.017] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Revised: 06/20/2019] [Accepted: 06/22/2019] [Indexed: 11/20/2022]
Abstract
Ustilago maydis is an aerobic basidiomycete that depends on oxidative phosphorylation for its ATP supply, pointing to the mitochondrion as a key player in its energy metabolism. Mitochondrial respiratory complexes I, III2, and IV occur in supramolecular structures named respirasome. In this work, we characterized the subunit composition and the kinetics of NADH:Q oxidoreductase activity of the digitonine-solubilized respirasome (1600 kDa) and the free-complex I (990 kDa). In the presence of 2,6-dimethoxy-1,4-benzoquinone (DBQ) and cytochrome c, both the respirasome NADH:O2 and the NADH:DBQ oxidoreductase activities were inhibited by rotenone, antimycin A or cyanide. A value of 2.4 for the NADH oxidized/oxygen reduced ratio was determined for the respirasome activity, while ROS production was less than 0.001% of the oxygen consumption rate. Analysis of the NADH:DBQ oxidoreductase activity showed that respirasome was 3-times more active and showed higher affinity than free-complex I. The results suggest that the contacts between complexes I, III2 and IV in the respirasome increase the catalytic efficiency of complex I and regulate its activity to prevent ROS production.
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8
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Cogliati S, Lorenzi I, Rigoni G, Caicci F, Soriano ME. Regulation of Mitochondrial Electron Transport Chain Assembly. J Mol Biol 2018; 430:4849-4873. [DOI: 10.1016/j.jmb.2018.09.016] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Revised: 09/20/2018] [Accepted: 09/25/2018] [Indexed: 12/26/2022]
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9
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Abstract
Mitochondria contain their own genome that encodes for a small number of proteins, while the vast majority of mitochondrial proteins is produced on cytosolic ribosomes. The formation of respiratory chain complexes depends on the coordinated biogenesis of mitochondrially encoded and nuclear-encoded subunits. In this review, we describe pathways that adjust mitochondrial protein synthesis and import of nuclear-encoded subunits to the assembly of respiratory chain complexes. Furthermore, we outline how defects in protein import into mitochondria affect nuclear gene expression to maintain protein homeostasis under physiological and stress conditions.
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Affiliation(s)
- Chantal Priesnitz
- Institute of Biochemistry and Molecular Biology, Center for Biochemistry and Molecular Cell Research (ZBMZ), Faculty of Medicine, University of Freiburg, D-79104 Freiburg, Germany
- Faculty of Biology, University of Freiburg, D-79104 Freiburg, Germany
| | - Thomas Becker
- Institute of Biochemistry and Molecular Biology, Center for Biochemistry and Molecular Cell Research (ZBMZ), Faculty of Medicine, University of Freiburg, D-79104 Freiburg, Germany
- BIOSS Centre for Biological Signaling Studies, University of Freiburg, D-79104 Freiburg, Germany
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10
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Franco LVR, Su CH, McStay GP, Yu GJ, Tzagoloff A. Cox2p of yeast cytochrome oxidase assembles as a stand-alone subunit with the Cox1p and Cox3p modules. J Biol Chem 2018; 293:16899-16911. [PMID: 30224355 DOI: 10.1074/jbc.ra118.004138] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Revised: 09/11/2018] [Indexed: 11/06/2022] Open
Abstract
Cytochrome oxidase (COX) is a hetero-oligomeric complex of the mitochondrial inner membrane that reduces molecular oxygen to water, a reaction coupled to proton transfer from the mitochondrial matrix to the intermembrane space. In the yeast Saccharomyces cerevisiae, COX is composed of 11-13 different polypeptide subunits. Here, using pulse labeling of mitochondrial gene products in isolated yeast mitochondria, combined with purification of tagged COX subunits and ancillary factors, we studied the Cox2p assembly intermediates. Analysis of radiolabeled Cox2p obtained in pulldown assays by native gel electrophoresis revealed the existence of several assembly intermediates, the largest of which had an estimated mass of 450-550 kDa. None of the other known subunits of COX were present in these Cox2p intermediates. This was also true for the several ancillary factors having still undefined functions in COX assembly. In agreement with earlier evidence, Cox18p and Cox20p, previously shown to be involved in processing and in membrane insertion of the Cox2p precursor, were found to be associated with the two largest Cox2p intermediates. A small fraction of the Cox2p module contained Sco1p and Coa6p, which have been implicated in metalation of the binuclear copper site on this subunit. Our results indicate that following its insertion into the mitochondrial inner membrane, Cox2p assembles as a stand-alone protein with the compositionally more complex Cox1p and Cox3p modules.
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Affiliation(s)
- Leticia Veloso R Franco
- From the Department of Biological Sciences, Columbia University, New York, New York 10027 and
| | - Chen-Hsien Su
- From the Department of Biological Sciences, Columbia University, New York, New York 10027 and
| | - Gavin P McStay
- Department of Biological Sciences, Staffordshire University, Stoke-on-Trent, ST4 2DF, United Kingdom
| | - George J Yu
- From the Department of Biological Sciences, Columbia University, New York, New York 10027 and
| | - Alexander Tzagoloff
- From the Department of Biological Sciences, Columbia University, New York, New York 10027 and
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11
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Mansilla N, Racca S, Gras DE, Gonzalez DH, Welchen E. The Complexity of Mitochondrial Complex IV: An Update of Cytochrome c Oxidase Biogenesis in Plants. Int J Mol Sci 2018; 19:ijms19030662. [PMID: 29495437 PMCID: PMC5877523 DOI: 10.3390/ijms19030662] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Revised: 01/26/2018] [Accepted: 01/29/2018] [Indexed: 12/20/2022] Open
Abstract
Mitochondrial respiration is an energy producing process that involves the coordinated action of several protein complexes embedded in the inner membrane to finally produce ATP. Complex IV or Cytochrome c Oxidase (COX) is the last electron acceptor of the respiratory chain, involved in the reduction of O2 to H2O. COX is a multimeric complex formed by multiple structural subunits encoded in two different genomes, prosthetic groups (heme a and heme a3), and metallic centers (CuA and CuB). Tens of accessory proteins are required for mitochondrial RNA processing, synthesis and delivery of prosthetic groups and metallic centers, and for the final assembly of subunits to build a functional complex. In this review, we perform a comparative analysis of COX composition and biogenesis factors in yeast, mammals and plants. We also describe possible external and internal factors controlling the expression of structural proteins and assembly factors at the transcriptional and post-translational levels, and the effect of deficiencies in different steps of COX biogenesis to infer the role of COX in different aspects of plant development. We conclude that COX assembly in plants has conserved and specific features, probably due to the incorporation of a different set of subunits during evolution.
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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, 3000 Santa Fe, Argentina.
| | - Sofia Racca
- Instituto de Agrobiotecnología del Litoral (CONICET-UNL), Cátedra de Biología Celular y Molecular, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, 3000 Santa Fe, Argentina.
| | - Diana E Gras
- Instituto de Agrobiotecnología del Litoral (CONICET-UNL), Cátedra de Biología Celular y Molecular, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, 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, 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, 3000 Santa Fe, Argentina.
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12
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Derbikova KS, Levitsky SA, Chicherin IV, Vinogradova EN, Kamenski PA. Activation of Yeast Mitochondrial Translation: Who Is in Charge? BIOCHEMISTRY (MOSCOW) 2018; 83:87-97. [DOI: 10.1134/s0006297918020013] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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13
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Plasticity of Mitochondrial Translation. Trends Cell Biol 2017; 27:712-721. [DOI: 10.1016/j.tcb.2017.05.004] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Revised: 05/15/2017] [Accepted: 05/16/2017] [Indexed: 11/21/2022]
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14
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Box JM, Kaur J, Stuart RA. MrpL35, a mitospecific component of mitoribosomes, plays a key role in cytochrome c oxidase assembly. Mol Biol Cell 2017; 28:3489-3499. [PMID: 28931599 PMCID: PMC5683760 DOI: 10.1091/mbc.e17-04-0239] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2017] [Revised: 08/28/2017] [Accepted: 09/11/2017] [Indexed: 01/03/2023] Open
Abstract
Mitoribosomes perform the synthesis of the core components of the oxidative phosphorylation (OXPHOS) system encoded by the mitochondrial genome. We provide evidence that MrpL35 (mL38), a mitospecific component of the yeast mitoribosomal central protuberance, assembles into a subcomplex with MrpL7 (uL5), Mrp7 (bL27), and MrpL36 (bL31) and mitospecific proteins MrpL17 (mL46) and MrpL28 (mL40). We isolated respiratory defective mrpL35 mutant yeast strains, which do not display an overall inhibition in mitochondrial protein synthesis but rather have a problem in cytochrome c oxidase complex (COX) assembly. Our findings indicate that MrpL35, with its partner Mrp7, play a key role in coordinating the synthesis of the Cox1 subunit with its assembly into the COX enzyme and in a manner that involves the Cox14 and Coa3 proteins. We propose that MrpL35 and Mrp7 are regulatory subunits of the mitoribosome acting to coordinate protein synthesis and OXPHOS assembly events and thus the bioenergetic capacity of the mitochondria.
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Affiliation(s)
- Jodie M Box
- Department of Biological Sciences, Marquette University, Milwaukee, WI 53233
| | - Jasvinder Kaur
- Department of Biological Sciences, Marquette University, Milwaukee, WI 53233
| | - Rosemary A Stuart
- Department of Biological Sciences, Marquette University, Milwaukee, WI 53233
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15
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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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