Coi1 is a novel assembly factor of the yeast complex III–complex IV supercomplex

The yeast bc1 complex (complex III) and cytochrome oxidase (complex IV) are mosaics of core subunits encoded by the mitochondrial genome and additional nuclear-encoded proteins imported from the cytosol. Both complexes build various supramolecular assemblies in the mitochondrial inner membrane. The formation of the individual complexes and their supercomplexes depends on the activity of dedicated assembly factors. We identified a so far uncharacterized mitochondrial protein (open reading frame YDR381C-A) as an important assembly factor for complex III, complex IV, and their supercomplexes. Therefore we named this protein Cox interacting (Coi) 1. Deletion of COI1 results in decreased respiratory growth, reduced membrane potential, and hampered respiration, as well as slow fermentative growth at low temperature. In addition, coi1Δ cells harbor reduced steady-state levels of subunits of complexes III and IV and of the assembled complexes and supercomplexes. Interaction of Coi1 with respiratory chain subunits seems transient, as it appears to be a stoichiometric subunit neither of complex III nor of complex IV. Collectively this work identifies a novel protein that plays a role in the assembly of the mitochondrial respiratory chain.

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Inhibition of proteasomal degradation rescues a pathogenic variant of mitochondrial Respiratory chain assembly 1 factor

10.1101/375725 ◽

2018 ◽

Author(s):

Karthik Mohanraj ◽

Michal Wasilewski ◽

Cristiane Benincá ◽

Dominik Cysewski ◽

Jarosław Poznanski ◽

...

Keyword(s):

Respiratory Chain ◽

Mitochondrial Diseases ◽

Proteasome Inhibition ◽

Mitochondrial Respiratory Chain ◽

Intermembrane Space ◽

Respiratory Chain Complexes ◽

Complex Iv ◽

Mutant Proteins ◽

Assembly Factor ◽

Mitochondrial Respiratory

AbstractNuclear and mitochondrial genome mutations lead to various mitochondrial diseases, many of which affect the mitochondrial respiratory chain. The proteome of the intermembrane space (IMS) of mitochondria consists of several important assembly factors that participate in the biogenesis of mitochondrial respiratory chain complexes. The present study comprehensively analyzed a recently identified IMS protein, RESpiratory chain Assembly 1 (RESA1) factor, or cytochrome c oxidase assembly factor 7 (COA7) that is associated with a rare form of mitochondrial leukoencephalopathy and complex IV deficiency. We found that RESA1 requires the mitochondrial IMS import and assembly (MIA) pathway for efficient accumulation in the IMS. We also found that pathogenic mutant versions of RESA1 are imported slower than the wild type protein, and mislocalized mutant proteins are degraded in the cytosol by proteasome machinery. Interestingly, proteasome inhibition rescued both the mitochondrial localization of mutant RESA1 and complex IV activity in patient-derived fibroblasts. We propose that proteasome inhibition is a novel therapeutic approach for a broad range of mitochondrial pathologies that are associated with the excessive degradation of mitochondrial proteins that is caused by genetic mutations or biogenesis defects.

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Mitochondriomics reveals the underlying neuoprotective mechanism of TrkB receptor agonist R13 in the 5×FAD mice

10.1101/2021.02.08.430227 ◽

2021 ◽

Author(s):

Xiao Li ◽

Ting Li ◽

Hao Yu ◽

Shupeng Li ◽

Zaijun Zhang ◽

...

Keyword(s):

Fatty Acid ◽

Mitochondrial Biogenesis ◽

Mitochondrial Protein ◽

Mitochondrial Respiratory Chain ◽

Complex Iii ◽

Mitochondrial Oxidative Phosphorylation ◽

Beta Oxidation ◽

Complex Iv ◽

Trkb Receptor ◽

Fatty Acid Beta Oxidation

AbstractDecreased energy metabolism and mitochondrial biogenesis defects are implicated in the pathogenesis of Alzheimer’s disease (AD). In present study, mitochondriomics analysis revealed significant effects of R13, a prodrug of 7,8-dihydroxyflavone, on mitochondrial protein expression profile, including the proteins related to the biological processes: fatty acid beta-oxidation, fatty acid metabolic process, mitochondrial electron transport, and mitochondrial respiratory chain. Cluster analysis of mitochondriomics demonstrated that R13 promoted mitochondrial oxidative phosphorylation (OXPHOS). The functional analysis showed that R13 increased ATP levels and enhanced OXPHOS including complex I, complex II, complex III and complex IV. R13 treatment increased mitochondrial biogenesis by regulating the levels of p-AMPKα, p-CREB, PGC-1α, NRF1 and TFAM as a consequence of activation of TrkB receptor in the 5×FAD mice. Finally, R13 significantly reduced the levels of tau phosphorylation and Aβ plaque. Our data suggest that R13 may be used for treating AD via enhancing mitochondrial biogenesis and metabolism.

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Specific requirements of nonbilayer phospholipids in mitochondrial respiratory chain function and formation

Molecular Biology of the Cell ◽

10.1091/mbc.e15-12-0865 ◽

2016 ◽

Vol 27 (14) ◽

pp. 2161-2171 ◽

Cited By ~ 31

Author(s):

Charli D. Baker ◽

Writoban Basu Ball ◽

Erin N. Pryce ◽

Vishal M. Gohil

Keyword(s):

Respiratory Chain ◽

Mitochondrial Membrane ◽

Phospholipid Composition ◽

Mitochondrial Respiratory Chain ◽

Complex Iii ◽

Specific Requirement ◽

Transport Pathway ◽

Contact Sites ◽

Yeast Mutants ◽

Mitochondrial Respiratory

Mitochondrial membrane phospholipid composition affects mitochondrial function by influencing the assembly of the mitochondrial respiratory chain (MRC) complexes into supercomplexes. For example, the loss of cardiolipin (CL), a signature non–bilayer-forming phospholipid of mitochondria, results in disruption of MRC supercomplexes. However, the functions of the most abundant mitochondrial phospholipids, bilayer-forming phosphatidylcholine (PC) and non–bilayer-forming phosphatidylethanolamine (PE), are not clearly defined. Using yeast mutants of PE and PC biosynthetic pathways, we show a specific requirement for mitochondrial PE in MRC complex III and IV activities but not for their formation, whereas loss of PC does not affect MRC function or formation. Unlike CL, mitochondrial PE or PC is not required for MRC supercomplex formation, emphasizing the specific requirement of CL in supercomplex assembly. Of interest, PE biosynthesized in the endoplasmic reticulum (ER) can functionally substitute for the lack of mitochondrial PE biosynthesis, suggesting the existence of PE transport pathway from ER to mitochondria. To understand the mechanism of PE transport, we disrupted ER–mitochondrial contact sites formed by the ERMES complex and found that, although not essential for PE transport, ERMES facilitates the efficient rescue of mitochondrial PE deficiency. Our work highlights specific roles of non–bilayer-forming phospholipids in MRC function and formation.

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Defects in mitochondrial protein synthesis and respiratory chain activity segregate with the tRNA(Leu(UUR)) mutation associated with mitochondrial myopathy, encephalopathy, lactic acidosis, and strokelike episodes

Molecular and Cellular Biology ◽

10.1128/mcb.12.2.480-490.1992 ◽

1992 ◽

Vol 12 (2) ◽

pp. 480-490

Author(s):

M P King ◽

Y Koga ◽

M Davidson ◽

E A Schon

Keyword(s):

Steady State ◽

Lactic Acidosis ◽

Respiratory Chain ◽

Mitochondrial Myopathy ◽

Polyacrylamide Gel Electrophoresis ◽

Mitochondrial Protein ◽

Morphological Characteristics ◽

Nucleotide Position ◽

Mitochondrial Translation ◽

Steady State Levels

Cytoplasts from two unrelated patients with MELAS (mitochondrial myopathy, encephalopathy, lactic acidosis, and strokelike episodes) harboring an A----G transition at nucleotide position 3243 in the tRNA(Leu(UUR)) gene of the mitochondrial genome were fused with human cells lacking endogenous mitochondrial DNA (mtDNA) (rho 0 cells). Selected cybrid lines, containing less than 15 or greater than or equal to 95% mutated genomes, were examined for differences in genetic, biochemical, and morphological characteristics. Cybrids containing greater than or equal to 95% mutant mtDNA, but not those containing normal mtDNA, exhibited decreases in the rates of synthesis and in the steady-state levels of the mitochondrial translation products. In addition, NADH dehydrogenase subunit 1 (ND 1) exhibited a slightly altered mobility on polyacrylamide gel electrophoresis. The mutation also correlated with a severe respiratory chain deficiency. A small but consistent increase in the steady-state levels of an RNA transcript corresponding to 16S rRNA + tRNA(Leu(UUR)) + ND 1 genes was detected. However, there was no evidence of major errors in processing of the heavy-strand-encoded transcripts or of altered steady-state levels or ratios of mitochondrial rRNAs or mRNAs. These results provide evidence for a direct relationship between the tRNALeu(UUR) mutation and the pathogenesis of this mitochondrial disease.

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Succinimidyl oleate, established inhibitor of CD36/FAT translocase inhibits complex III of mitochondrial respiratory chain

Biochemical and Biophysical Research Communications ◽

10.1016/j.bbrc.2009.12.050 ◽

2010 ◽

Vol 391 (3) ◽

pp. 1348-1351 ◽

Cited By ~ 6

Author(s):

Zdeněk Drahota ◽

Marek Vrbacký ◽

Hana Nůsková ◽

Ludmila Kazdová ◽

Václav Zídek ◽

...

Keyword(s):

Respiratory Chain ◽

Mitochondrial Respiratory Chain ◽

Complex Iii ◽

Mitochondrial Respiratory

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Mitochondrial Respiratory Chain Protein Co-Regulation in the Human Brain

10.1101/2021.07.19.452923 ◽

2021 ◽

Author(s):

Caroline Trumpff ◽

Edward Owusu-Ansah ◽

Hans-Ulrich Klein ◽

Annie Lee ◽

Vladislav Petyuk ◽

...

Keyword(s):

Human Brain ◽

Respiratory Chain ◽

Complex I ◽

Molecular Mechanisms ◽

Nuclear Dna ◽

Mitochondrial Protein ◽

Mitochondrial Respiratory Chain ◽

Mtdna Copy Number ◽

Mt Dna ◽

Mitochondrial Respiratory

Mitochondrial respiratory chain (RC) function requires the stochiometric interaction among dozens of proteins but their co-regulation has not been defined in the human brain. Here, using quantitative proteomics across three independent cohorts we systematically characterized the co-regulation patterns of mitochondrial RC proteins in the human dorsolateral prefrontal cortex (DLPFC). Whereas the abundance of RC protein subunits that physically assemble into stable complexes were correlated, indicating their co-regulation, RC assembly factors exhibited modest co-regulation. Within complex I, nuclear DNA-encoded subunits exhibited >2.5-times higher co-regulation than mitochondrial (mt)DNA-encoded subunits. Moreover, mtDNA copy number was unrelated to mtDNA-encoded subunits abundance, suggesting that mtDNA content is not limiting. Alzheimer disease (AD) brains exhibited reduced abundance of complex I RC subunits, an effect largely driven by a 2-4% overall lower mitochondrial protein content. These findings provide foundational knowledge to identify molecular mechanisms contributing to age- and disease-related erosion of mitochondrial function in the human brain.

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Novel Role of ATPase Subunit C Targeting Peptides Beyond Mitochondrial Protein Import

Molecular Biology of the Cell ◽

10.1091/mbc.e09-06-0483 ◽

2010 ◽

Vol 21 (1) ◽

pp. 131-139 ◽

Cited By ~ 19

Author(s):

Cristofol Vives-Bauza ◽

Jordi Magrané ◽

Antoni L. Andreu ◽

Giovanni Manfredi

Keyword(s):

Respiratory Chain ◽

Protein Import ◽

Mitochondrial Protein ◽

Atp Synthesis ◽

Mitochondrial Respiratory Chain ◽

Genetic Redundancy ◽

Mitochondrial Protein Import ◽

Atpase Subunit ◽

Subunit C ◽

And Function

In mammals, subunit c of the F1F0-ATP synthase has three isoforms (P1, P2, and P3). These isoforms differ by their cleavable mitochondrial targeting peptides, whereas the mature peptides are identical. To investigate this apparent genetic redundancy, we knocked down each of the three subunit c isoform by RNA interference in HeLa cells. Silencing any of the subunit c isoforms individually resulted in an ATP synthesis defect, indicating that these isoforms are not functionally redundant. We found that subunit c knockdown impaired the structure and function of the mitochondrial respiratory chain. In particular, P2 silencing caused defective cytochrome oxidase assembly and function. Because the expression of exogenous P1 or P2 was able to rescue the respective silencing phenotypes, but the two isoforms were unable to cross-complement, we hypothesized that their functional specificity resided in their targeting peptides. In fact, the expression of P1 and P2 targeting peptides fused to GFP variants rescued the ATP synthesis and respiratory chain defects in the silenced cells. Our results demonstrate that the subunit c isoforms are nonredundant, because they differ functionally by their targeting peptides, which, in addition to mediating mitochondrial protein import, play a yet undiscovered role in respiratory chain maintenance.

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Respiratory chain supercomplexes associate with the cysteine desulfurase complex of the iron–sulfur cluster assembly machinery

Molecular Biology of the Cell ◽

10.1091/mbc.e17-09-0555 ◽

2018 ◽

Vol 29 (7) ◽

pp. 776-785 ◽

Cited By ~ 5

Author(s):

Lena Böttinger ◽

Christoph U. Mårtensson ◽

Jiyao Song ◽

Nicole Zufall ◽

Nils Wiedemann ◽

...

Keyword(s):

Respiratory Chain ◽

Complex Iii ◽

Bc1 Complex ◽

Cytochrome Bc1 Complex ◽

Respiratory Chain Complexes ◽

Cysteine Desulfurase ◽

Complex Iv ◽

Iron Sulfur Cluster ◽

Iron Sulfur ◽

Chain Complexes

Mitochondria are the powerhouses of eukaryotic cells. The activity of the respiratory chain complexes generates a proton gradient across the inner membrane, which is used by the F1FO-ATP synthase to produce ATP for cellular metabolism. In baker’s yeast, Saccharomyces cerevisiae, the cytochrome bc1 complex (complex III) and cytochrome c oxidase (complex IV) associate in respiratory chain supercomplexes. Iron–sulfur clusters (ISC) form reactive centers of respiratory chain complexes. The assembly of ISC occurs in the mitochondrial matrix and is essential for cell viability. The cysteine desulfurase Nfs1 provides sulfur for ISC assembly and forms with partner proteins the ISC-biogenesis desulfurase complex (ISD complex). Here, we report an unexpected interaction of the active ISD complex with the cytochrome bc1 complex and cytochrome c oxidase. The individual deletion of complex III or complex IV blocks the association of the ISD complex with respiratory chain components. We conclude that the ISD complex binds selectively to respiratory chain supercomplexes. We propose that this molecular link contributes to coordination of iron–sulfur cluster formation with respiratory activity.

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