Respiratory chain protein analysis and gene expression profiles of fibroblast cell lines from 9 patients with SURF1 gene mutations
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE26322 | GEO | 2011/06/01
SECONDARY ACCESSION(S): PRJNA136773
REPOSITORIES: GEO
Similar Datasets
Project description:Upregulation of CI, CIII and CV at a protein but not mRNA level in LSCOX cell with COX deficiency due to SURF1 mutations compared to control – evidence for posttranscriptional compensatory mechanism. Two-condition experiment, patients vs. controls cells. Biological replicates: 3 controls and 9 patients, independently grown and harvested.
2011-06-01 | E-GEOD-26322 | biostudies-arrayexpress
Project description:The oxidative phosphorylation (OXPHOS) system localized in the inner mitochondrial membrane secures production of the majority of ATP in mammalian organisms. Individual OXPHOS complexes form supramolecular assemblies termed supercomplexes. The complexes are linked not only by their function but also by interdependence of individual complex biogenesis or maintenance. For instance, cytochrome c oxidase (cIV, COX) or cytochrome bc1 complex (cIII) deficiencies affect the level of fully assembled NADH dehydrogenase (cI) in monomeric as well as supercomplex forms. It was hypothesized that cI is affected at the level of enzyme assembly as well as at the level of cI stability and maintenance. However, the true nature of interdependency between cI and cIV is not fully understood yet. We used a HEK293 cellular model where the COX4 subunit was completely knocked out, serving as an ideal system to study interdependency of cI and cIV, as early phases of cIV assembly process are disrupted. Total absence of cIV was accompanied by profound deficiency of cI, documented by decrease in the levels of cI subunits and significantly reduced amount of assembled cI. Supercomplexes assembled from cI, cIII and cIV were missing in COX4 KO due to loss of cIV and decrease in cI amount. Pulse-chase metabolic labelling of mtDNA-encoded proteins uncovered a decrease in the translation of cIV and cI subunits. Moreover, partial impairment of mitochondrial protein synthesis correlated with decreased content of mitochondrial ribosomal proteins. In addition, complexome profiling revealed accumulation of cI assembly intermediates indicating that cI biogenesis, rather than stability, was the affected process. We propose, that impairment of mitochondrial protein synthesis caused by cIV deficiency represents one of the mechanisms which may couple biogenesis of cI and cIV.
2021-02-18 | PXD023367 | Pride
Project description:Loss of SURF1, a Complex IV assembly protein, was reported to increase lifespan in mice despite dramatically lower cytochrome oxidase (COX) activity. Consistent with this, our previous studies found advantageous changes in metabolism (reduced adiposity, increased insulin sensitivity and mitochon-drial biogenesis) in Surf1-/- mice. The lack of deleterious phenotypes in Surf1-/- mice is contrary to the hypothesis that mitochondrial dysfunction contributes to aging. We found only a modest (non-significant) extension of lifespan (7% median, 16% maximum) and no change in healthspan indices in Surf1-/- vs Surf1+/+ mice despite substantial decreases in COX activity (22-87% across tissues). Dietary restriction (DR) increased median lifespan in both Surf1+/+ and Surf1-/- mice (36 and 19%, respectively). We measured gene expression, metabolites and targeted expression of key metabolic proteins in adi-pose tissue, liver and brain in Surf1+/+ and Surf1-/- mice. Gene expression was differentially regulated in a tissue specific pattern. We found that many proteins and metabolites are downregulated in Surf1-/- adipose tissue and reversed by DR, while in brain most metabolites that changed were elevated in Surf1-/- mice. Finally, mitochondrial unfolded protein response (UPRmt)-associated proteins were not uniformly altered by age or genotype, suggesting the UPRmt is not a key player in aging or the response to reduced COX activity. While the changes in gene expression and metabolism may represent com-pensatory responses to mitochondrial stress, the important outcome of this study is that lifespan and healthspan are not compromised in Surf1-/- mice, suggesting that mitochondrial deficiencies may not be a critical determinant of lifespan.
2020-11-20 | GSE107191 | GEO
Project description:Leigh Syndrome (LS) is the most common early-onset, progressive mitochondrial encephalopathy usually leading to early death. The single most prevalent cause of LS is occurrence of mutations in the hSurf1 gene. LSSurf1 patients show a marked and specific decrease in the activity of mitochondrial respiratory chain complex IV (cytochrome c oxidase, COX). hSurf1 encodes an inner membrane mitochondrial protein involved in COX assembly. We established a D. melanogaster model of LS based on the post-transcriptional silencing of CG9943, the Drosophila homolog of hSurf1. Knock down of Surf1 was induced (i) ubiquitously, which led to larval lethality; (ii) in the mesodermal derivatives, which led to pupal lethality; (iii) in the central nervous system, which allowed survival; and (iv) at specific developmental stages. A biochemical characterization was carried out in knock down individuals, which unexpectedly revealed defects in all complexes of the mitochondrial respiratory chain (MRC) included the F-ATP synthase (complex V) in larvae, and a COX-specific impairment in adults. Silencing of Surf1 expression in Drosophila S2R+ cells led to loss of COX activity associated with decreased oxygen consumption. We conclude that Surf1 is essential for COX activity and mitochondrial function in D. melanogaster, and provide a new tool to clarify the pathogenic mechanisms of LS.
2014-11-04 | GSE58301 | GEO
Project description:Combining mass spectrometry based chemical cross-linking and complexome profiling, we analyzed the interactome of heart mitochondria. We focused on complexes of oxidative phosphorylation and found that dimeric apoptosis inducing factor 1 (AIFM1) forms a defined complex with ~10% of monomeric cytochrome c oxidase (COX), but hardly interacts with respiratory chain supercomplexes. Multiple AIFM1 inter-crosslinks engaging six different COX subunits provided structural restraints to build a detailed atomic model of the COX-AIFM12 complex. Application of two complementary proteomic approaches thus provided unexpected insight into the macromolecular organization of the mitochondrial complexome. Our structural model excludes direct electron transfer between AIFM1 and COX. Notably however, the binding site of cytochrome c remains accessible allowing formation of a ternary complex. The discovery of the previously overlooked COX-AIFM12 complex and clues provided by the structural model hint at a role of AIFM1 in OXPHOS biogenesis and in programmed cell death.
2021-09-09 | PXD025102 | Pride
Project description:ra16-03_rotenone - rotenone - How does inhibition of CI enhance organogenesis? - NA
2019-01-01 | GSE107673 | GEO
Project description:ra16-03_rotenone - rotenone_complex i mutants - How does inhibition of CI enhance organogenesis
2019-01-01 | GSE117269 | GEO
Project description:The mammalian oxidative phosphorylation (OXPHOS) system in the inner mitochondrial membrane comprises respiratory chain complexes I-IV (CI-CIV) and ATP synthase. Together, these protein complexes harvest metabolic energy to generate ATP, the cellular energy currency. The inner mitochondrial membrane is abundant in OXPHOS complexes and CI, CIII and CIV exhibit specific protein-protein interactions to form stable supercomplex assemblies, exemplified by the respirasome (CI-CIII2-CIV). Respirasomes are conserved in evolution, and as well documented by biochemical and structural methods. However, their physiological roles are much debated, despite a substantial literature suggesting their importance in facilitating catalysis and regulating turnover in response to metabolic demand. To investigate the in vivo role of respirasomes, we deleted a short conserved, charged loop in the UQCRC1 subunit of CIII that contacts CI. The resulting homozygous knock-in mice show profoundly decreased levels of respirasomes on blue native polyacrylamide gel electrophoresis (BN-PAGE) and complexome profiling proteomics analyses of different tissues, although the individual complexes appear unaffected. In vivo The spatial organization of respirasomes in vivo was altered in knock-in mice as shown by cross-linking experiments on intact mitochondria. Surprisingly, the mutant mice are healthy, with normal respiratory chain capacity and normal exercise tolerance. Therefore, respirasomes are dispensable for OXPHOS function in vivo.
2023-03-11 | PXD031345 | Pride
Project description:The mammalian respiratory chain complexes I, III2 and IV (CI, CIII2 and CIV) are critical for cellular bioenergetics and form a stable assembly, the respirasome (CI-CIII2-CIV), that is biochemically and structurally well documented. The role of the respirasome in bioenergetics and regulation of metabolism is subject to intense debate and is difficult to study because the individual respiratory chain complexes coexist together with high levels of respirasomes. To critically investigate the in vivo role of the respirasome, we generated homozygous knock-in mice that have normal levels of respiratory chain complexes but profoundly decreased levels of respirasomes. Surprisingly, the mutant mice are healthy, with preserved respiratory chain capacity and normal exercise performance. Our findings show that high levels of respirasomes are dispensable for maintaining bioenergetics and physiology in the mouse, but raises questions about their alternate functions, such as relating to regulation of protein stability and prevention of age-associated protein aggregation.
2024-03-19 | PXD023846 | Pride
Project description:Regulation of the turnover of complex I (CI), the largest mitochondrial respiratory chain complex remains enigmatic, despite huge advancement in understanding its structure and the assembly steps in recent years. Although some studies indicated that CI might be remodelled in response to various stimuli, the mechanism mediating these putative changes is unknown. Here, we report that the NADH-oxidising N-module which sits on the tip of the CI peripheral arm is turned over at a higher rate and largely independently of the rest of the complex. The N-module turnover is mediated by mitochondrial matrix protease ClpXP, which selectively removes and degrades damaged core subunits. The observed mechanism seems to be a safeguard against accumulation of dysfunctional CI arising from inactivation of the N-module subunits due to attrition caused by extensive redox activity. This CI salvage pathway maintains highly functional CI and healthy mitochondria through an energetically favourable mechanism that demands much lower energetic cost than de novo synthesis and reassembly of the entire CI.
2020-03-05 | PXD014897 | Pride