Functional role of mitochondrial respiratory supercomplexes

Genova, Maria Luisa; Lenaz, Giorgio

doi:10.1016/j.bbabio.2013.11.002

Cited by 274 publications

(203 citation statements)

References 176 publications

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“…5, A and B) in line with the plasticity model of the OXPHOS complexes (31). Thus, csBN-MS opens a way to study the stoichiometry of the OXPHOS (super-)complexes in a precise and quantitative manner to challenge the opposing models for structural organization and function of the dynamic entity (31,32). The high resolution of the method is also of interest for resolving sub-complexes and assembly intermediates of the (super-)-complexes.…”

Section: Fig 5 Analysis Of Respiratory Chain Complexes By Csbn-msmentioning

confidence: 93%

Cryo-slicing Blue Native-Mass Spectrometry (csBN-MS), a Novel Technology for High Resolution Complexome Profiling

Müller

Bildl

Haupt

et al. 2016

Molecular & Cellular Proteomics

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Blue native (BN)1 -PAGE and its colorless variant, colorless native PAGE, were originally developed by Schä gger and co-workers as end point separation methods for characterization of solubilized mitochondrial membrane protein (super-)-complexes under close-to-native conditions (1-3). Subsequently, native gel electrophoresis became the method of choice for first dimension separation followed by second dimension SDS-PAGE in two-dimensional gel-based proteomic analyses (2D-BN) of membrane protein complexes. After staining of the gel-separated proteins, protein spots are individually analyzed by different mass spectrometric methods, and the identified proteins were assigned to complexes based on their co-migration pattern (2D-BN-MS (4)). However, these 2D-BN-MS approaches exhibit the following severe shortcomings: (i) they are critically dependent on the staining properties of individual proteins; (ii) the size resolution of protein complexes is low; and (iii) the assignment of identified proteins to spots and complexes may be ambiguous. Therefore, application of 2D-BN-MS has remained largely restricted to the characterization of highly abundant and well defined membrane protein complexes such as complexes I-V of the respiratory chain in mitochondria (5-7), photosynthetic complexes (8 -10), or viruses (11).In a first attempt to overcome these shortcomings of 2D-BN-MS, Wessels et al. (12) coupled BN-PAGE separation more directly to MS analysis by manually cutting the gel lane into 24 slices/sections of about 2 mm width that were separately digested and analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Their study on HEK cell mitochondria identified 59 of the 90 canonical subunits of the oxidative respiratory chain (OXPHOS) complexes I-V. The respective protein abundance profiles (based on standard label-free quantification) showed clustering of their peak maxima into the expected complexes I-V. Since then, this onedimensional BN-MS methodology has been gradually improved with respect to quality of the native gel separation, LC-MS/MS sensitivity, and robustness of the quantitative evaluation. Thus, two recent studies on human mitochondrial preparations (each analyzing two BN separations in 60 and 24 slices, respectively) reported identification and hierarchical profile clustering of 464 (13)

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Section: Fig 5 Analysis Of Respiratory Chain Complexes By Csbn-msmentioning

confidence: 93%

Cryo-slicing Blue Native-Mass Spectrometry (csBN-MS), a Novel Technology for High Resolution Complexome Profiling

Müller

Bildl

Haupt

et al. 2016

Molecular & Cellular Proteomics

View full text Add to dashboard Cite

show abstract

“…It is difficult to envisage mechanistically how supercomplexes could exert primary effects on the formation of reactive oxygen species, and only limited circumstantial evidence has been presented to support this proposal (33). Effects on complex stability and assembly (34) have been proposed but support for the stability hypothesis is based on genetic ablation of "partner" enzymes (35)(36)(37), causing substantial disruption that impedes respiratory-chain turnover.…”

Section: Discussionmentioning

confidence: 99%

Kinetic evidence against partitioning of the ubiquinone pool and the catalytic relevance of respiratory-chain supercomplexes

Blaza

Serreli

Jones

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

163

126

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In mitochondria, four respiratory-chain complexes drive oxidative phosphorylation by sustaining a proton-motive force across the inner membrane that is used to synthesize ATP. The question of how the densely packed proteins of the inner membrane are organized to optimize structure and function has returned to prominence with the characterization of respiratory-chain supercomplexes. Supercomplexes are increasingly accepted structural entities, but their functional and catalytic advantages are disputed. Notably, substrate "channeling" between the enzymes in supercomplexes has been proposed to confer a kinetic advantage, relative to the rate provided by a freely accessible, common substrate pool. Here, we focus on the mitochondrial ubiquinone/ubiquinol pool. We formulate and test three conceptually simple predictions of the behavior of the mammalian respiratory chain that depend on whether channeling in supercomplexes is kinetically important, and on whether the ubiquinone pool is partitioned between pathways. Our spectroscopic and kinetic experiments demonstrate how the metabolic pathways for NADH and succinate oxidation communicate and catalyze via a single, universally accessible ubiquinone/ubiquinol pool that is not partitioned or channeled. We reevaluate the major piece of contrary evidence from flux control analysis and find that the conclusion of substrate channeling arises from the particular behavior of a single inhibitor; we explain why different inhibitors behave differently and show that a robust flux control analysis provides no evidence for channeling. Finally, we discuss how the formation of respiratory-chain supercomplexes may confer alternative advantages on energy-converting membranes.supercomplex | respirasome | mitochondria | respiratory chain | ubiquinone C ontemporary models for the organization of respiratorychain complexes in energy-transducing membranes range from the fluid model to the respirasome model. In the fluid model each complex is a free and independent entity, and substrates exchange freely between enzymes through common ubiquinone/ubiquinol (Q) and cytochrome c ox /c red (cyt c) pools (1-3). In the respirasome model the complexes are assembled into units that contain everything required for catalysis; substrates are channeled between enzymes within the respirasome, not exchanged with external pools (4, 5). Intermediate models, in which some enzymes are free and some assembled into multienzyme supercomplexes, or in which supercomplexes are assembled and disassembled in response to changing conditions, are increasingly considered a realistic combination of these two extremes (6).Structural evidence for respiratory-chain supercomplexes, initiated by observations by blue native PAGE analyses of mammalian mitochondria (4, 7), has culminated in electron microscopy data that revealed the arrangement of complexes I, III, and IV in a particular class of isolated supercomplex assembly (8, 9); respiratory-chain supercomplexes have also been observed (at lower resolution) in the membrane (10...

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“…6 Also, CoQ levels in brain are remarkably stable in mammals and are independent from environment. 7 This is the base of understanding that a defective biosynthesis of CoQ 10 by mutations in any COQ genes, and secondary deficiencies by defects of respiratory chain complexes functions such as mtDNA depletions 14 or proteins involved in mitochondrial homeostasis cause mitochondrial diseases mainly with neuromuscular phenotype.…”

Section: Discussionmentioning

confidence: 99%

“…5 In mammals, CoQ levels are tissue specific and its concentration in mitochondria is very much balanced with electron chain complexes, contributing to prevent endogenous oxidative stress. 6 Among tissues, CoQ content in brain is very stable and highly independent of environment. 7 Furthermore, mutations of genes that are not part of respiratory chain also cause mitochondrial dysfunctions and may induce an adaptive decrease of CoQ 10 , named secondary deficiency, although the mechanisms are totally unknown.…”

Section: Introductionmentioning

confidence: 99%

Severe encephalopathy associated to pyruvate dehydrogenase mutations and unbalanced coenzyme Q10 content

et al. 2015

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Coenzyme Q 10 (CoQ 10 ) deficiency is associated to a variety of clinical phenotypes including neuromuscular and nephrotic disorders. We report two unrelated boys presenting encephalopathy, ataxia, and lactic acidosis, who died with necrotic lesions in different areas of brain. Levels of CoQ 10 and complex II+III activity were increased in both skeletal muscle and fibroblasts, but it was a consequence of higher mitochondria mass measured as citrate synthase. In fibroblasts, oxygen consumption was also increased, whereas steady state ATP levels were decreased. Antioxidant enzymes such as NQO1 and MnSOD and mitochondrial marker VDAC were overexpressed. Mitochondria recycling markers Fis1 and mitofusin, and mtDNA regulatory Tfam were reduced. Exome sequencing showed mutations in PDHA1 in the first patient and in PDHB in the second. These genes encode subunits of pyruvate dehydrogenase complex (PDH) that could explain the compensatory increase of CoQ 10 and a defect of mitochondrial homeostasis. These two cases describe, for the first time, a mitochondrial disease caused by PDH defects associated with unbalanced of both CoQ 10 content and mitochondria homeostasis, which severely affects the brain. Both CoQ 10 and mitochondria homeostasis appears as new markers for PDH associated mitochondrial disorders.

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Functional role of mitochondrial respiratory supercomplexes

Cited by 274 publications

References 176 publications

Cryo-slicing Blue Native-Mass Spectrometry (csBN-MS), a Novel Technology for High Resolution Complexome Profiling

Cryo-slicing Blue Native-Mass Spectrometry (csBN-MS), a Novel Technology for High Resolution Complexome Profiling

Kinetic evidence against partitioning of the ubiquinone pool and the catalytic relevance of respiratory-chain supercomplexes

Severe encephalopathy associated to pyruvate dehydrogenase mutations and unbalanced coenzyme Q10 content

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