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Mitochondrial supercomplexes

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https://www.readbyqxmd.com/read/29162722/docosahexaenoic-acid-lowers-cardiac-mitochondrial-enzyme-activity-by-replacing-linoleic-acid-in-the-phospholipidome
#1
E Madison Sullivan, Edward Ross Pennington, Genevieve C Sparagna, Maria J Torres, P Darrell Neufer, Mitchel Harris, James Washington, Ethan J Anderson, Tonya N Zeczycki, David A Brown, Saame Raza Shaikh
Cardiac mitochondrial phospholipid acyl chains regulate respiratory enzymatic activity. In several diseases, the rodent cardiac phospholipidome is extensively rearranged; however, whether specific acyl chains impair respiratory enzyme function is unknown. One unique remodeling event in the myocardium of obese and diabetic rodents is an increase in docosahexaenoic acid (DHA) levels. Here, we first confirmed that cardiac DHA levels are elevated in diabetic humans relative to controls. We then used dietary supplementation of a Western diet with DHA as a tool to promote cardiac acyl chain remodeling and to study its influence on respiratory enzyme function...
November 21, 2017: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/29103101/ischemic-preconditioning-protects-astrocytes-against-oxygen-glucose-deprivation-via-the-nuclear-erythroid-2-related-factor-2-pathway
#2
Srinivasan V Narayanan, Kunjan R Dave, Miguel A Perez-Pinzon
Induction of ischemic preconditioning (IPC) represents a potential therapy against cerebral ischemia by activation of adaptive pathways and modulation of mitochondria to induce ischemic tolerance to various cells and tissues. Mitochondrial dysfunction has been ascribed to contribute to numerous neurodegenerative conditions and cerebral ischemia. Nuclear erythroid 2-related factor 2 (Nrf2) is a transcription factor that has traditionally been involved in upregulating cellular antioxidant systems to combat oxidative stress in the brain; however, the association of Nrf2 with mitochondria in the brain remains unclear...
November 4, 2017: Translational Stroke Research
https://www.readbyqxmd.com/read/29067684/the-role-of-non-bilayer-phospholipids-in-mitochondrial-structure-and-function
#3
REVIEW
Writoban Basu Ball, John K Neff, Vishal M Gohil
Mitochondrial structure and function are influenced by the unique phospholipid composition of its membranes. While mitochondria contain all the major classes of phospholipids, recent studies have highlighted specific roles of the non-bilayer forming phospholipids phosphatidylethanolamine (PE) and cardiolipin (CL) in the assembly and activity of mitochondrial respiratory chain (MRC) complexes. The non-bilayer phospholipids are cone-shaped molecules that introduce curvature stress in the bilayer membrane and have been shown to impact mitochondrial fusion and fission...
October 25, 2017: FEBS Letters
https://www.readbyqxmd.com/read/29066618/epigenetic-modification-of-mir-663-controls-mitochondria-to-nucleus-retrograde-signaling-and-tumor-progression
#4
Trevor Carden, Bhupendra Singh, Ved Mooga, Prachi Bajpai, Keshav K Singh
The normal cellular function requires communication between mitochondria and the nucleus, termed mitochondria-to-nucleus retrograde signaling. Disruption of this mechanism has been implicated in the development of cancers. Many proteins are known modulators of retrograde signaling, but whether microRNAs (miRNAs) are also involved is unknown. We conducted a miRNA microarray analysis using RNA from a parental cell line, a rho0 line lacking mitochondrial DNA (mtDNA) and a rho0 line with restored mtDNA. We found that miR-663 was down-regulated in the mtDNA-depleted rho0 line...
October 24, 2017: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/29018038/increased-localization-of-app-c99-in-mitochondria-associated-er-membranes-causes-mitochondrial-dysfunction-in-alzheimer-disease
#5
Marta Pera, Delfina Larrea, Cristina Guardia-Laguarta, Jorge Montesinos, Kevin R Velasco, Rishi R Agrawal, Yimeng Xu, Robin B Chan, Gilbert Di Paolo, Mark F Mehler, Geoffrey S Perumal, Frank P Macaluso, Zachary Z Freyberg, Rebeca Acin-Perez, Jose Antonio Enriquez, Eric A Schon, Estela Area-Gomez
In the amyloidogenic pathway associated with Alzheimer disease (AD), the amyloid precursor protein (APP) is cleaved by β-secretase to generate a 99-aa C-terminal fragment (C99) that is then cleaved by γ-secretase to generate the β-amyloid (Aβ) found in senile plaques. In previous reports, we and others have shown that γ-secretase activity is enriched in mitochondria-associated endoplasmic reticulum (ER) membranes (MAM) and that ER-mitochondrial connectivity and MAM function are upregulated in AD We now show that C99, in addition to its localization in endosomes, can also be found in MAM, where it is normally processed rapidly by γ-secretase...
October 10, 2017: EMBO Journal
https://www.readbyqxmd.com/read/28988874/regulation-of-mammalian-13-subunit-cytochrome-c-oxidase-and-binding-of-other-proteins-role-of-ndufa4
#6
REVIEW
Bernhard Kadenbach
Cytochrome c oxidase (CcO) is the final oxygen accepting enzyme complex (complex IV) of the mitochondrial respiratory chain. In contrast to the other complexes (I, II, and III), CcO is highly regulated via isoforms for six of its ten nuclear-coded subunits, which are differentially expressed in species, tissues, developmental stages, and cellular oxygen concentrations. Recent publications have claimed that NADH dehydrogenase (ubiquinone) 1 alpha subcomplex 4 (NDUFA4), originally identified as subunit of complex I, represents a 14th subunit of CcO...
November 2017: Trends in Endocrinology and Metabolism: TEM
https://www.readbyqxmd.com/read/28981073/clarifying-the-supercomplex-the-higher-order-organization-of-the-mitochondrial-electron-transport-chain
#7
REVIEW
James A Letts, Leonid A Sazanov
The oxidative phosphorylation electron transport chain (OXPHOS-ETC) of the inner mitochondrial membrane is composed of five large protein complexes, named CI-CV. These complexes convert energy from the food we eat into ATP, a small molecule used to power a multitude of essential reactions throughout the cell. OXPHOS-ETC complexes are organized into supercomplexes (SCs) of defined stoichiometry: CI forms a supercomplex with CIII2 and CIV (SC I+III2+IV, known as the respirasome), as well as with CIII2 alone (SC I+III2)...
October 5, 2017: Nature Structural & Molecular Biology
https://www.readbyqxmd.com/read/28967163/mild-phenotypes-and-proper-supercomplex-assembly-in-human-cells-carrying-the-homoplasmic-m-15557g%C3%A2-%C3%A2-a-mutation-in-cytochrome-b-gene
#8
Luisa Iommarini, Anna Ghelli, Giulia Leone, Concetta Valentina Tropeano, Ivana Kurelac, Laura Benedetta Amato, Giuseppe Gasparre, Anna Maria Porcelli
Respiratory complex III (CIII) is the first enzymatic bottleneck of the mitochondrial respiratory chain both in its native dimeric form and in supercomplexes. The mammalian CIII comprises 11 subunits among which cytochrome b is central in the catalytic core, where oxidation of ubiquinol occurs at the Qo site. The Qo- or PEWY-motif of cytochrome b is the most conserved through species. Importantly, the highly conserved glutamate at position 271 (Glu271) has never been studied in higher eukaryotes so far and its role in the Q-cycle remains debated...
October 1, 2017: Human Mutation
https://www.readbyqxmd.com/read/28936218/atoma1-affects-the-oxphos-system-and-plant-growth-in-contrast-to-other-newly-identified-atp-independent-proteases-in-arabidopsis-mitochondria
#9
Iwona Migdal, Renata Skibior-Blaszczyk, Malgorzata Heidorn-Czarna, Marta Kolodziejczak, Arnold Garbiec, Hanna Janska
Compared with yeast, our knowledge on members of the ATP-independent plant mitochondrial proteolytic machinery is rather poor. In the present study, using confocal microscopy and immunoblotting, we proved that homologs of yeast Oma1, Atp23, Imp1, Imp2, and Oct1 proteases are localized in Arabidopsis mitochondria. We characterized these components of the ATP-independent proteolytic system as well as the earlier identified protease, AtICP55, with an emphasis on their significance in plant growth and functionality in the OXPHOS system...
2017: Frontiers in Plant Science
https://www.readbyqxmd.com/read/28914882/sirt3-sod2-maintains-osteoblast-differentiation-and-bone-formation-by-regulating-mitochondrial-stress
#10
Jing Gao, Zhihui Feng, Xueqiang Wang, Mengqi Zeng, Jing Liu, Shujun Han, Jie Xu, Lei Chen, Ke Cao, Jiangang Long, Zongfang Li, Weili Shen, Jiankang Liu
Recent studies have revealed robust metabolic changes during cell differentiation. Mitochondria, the organelles where many vital metabolic reactions occur, may play an important role. Here, we report the involvement of SIRT3-regulated mitochondrial stress in osteoblast differentiation and bone formation. In both the osteoblast cell line MC3T3-E1 and primary calvarial osteoblasts, robust mitochondrial biogenesis and supercomplex formation were observed during differentiation, accompanied by increased ATP production and decreased mitochondrial stress...
September 15, 2017: Cell Death and Differentiation
https://www.readbyqxmd.com/read/28888990/chemicals-or-mutations-that-target-mitochondrial-translation-can-rescue-the-respiratory-deficiency-of-yeast-bcs1-mutants
#11
C Panozzo, A Laleve, D Tribouillard-Tanvier, J Ostojić, C H Sellem, G Friocourt, A Bourand-Plantefol, A Burg, A Delahodde, M Blondel, G Dujardin
Bcs1p is a chaperone that is required for the incorporation of the Rieske subunit within complex III of the mitochondrial respiratory chain. Mutations in the human gene BCS1L (BCS1-like) are the most frequent nuclear mutations resulting in complex III-related pathologies. In yeast, the mimicking of some pathogenic mutations causes a respiratory deficiency. We have screened chemical libraries and found that two antibiotics, pentamidine and clarithromycin, can compensate two bcs1 point mutations in yeast, one of which is the equivalent of a mutation found in a human patient...
December 2017: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/28870773/mitochondrial-cytochrome-c-oxidase-biogenesis-recent-developments
#12
REVIEW
Alba Timón-Gómez, Eva Nývltová, Luciano A Abriata, Alejandro J Vila, Jonathan Hosler, Antoni Barrientos
Mitochondrial cytochrome c oxidase (COX) is the primary site of cellular oxygen consumption and is essential for aerobic energy generation in the form of ATP. Human COX is a copper-heme A hetero-multimeric complex formed by 3 catalytic core subunits encoded in the mitochondrial DNA and 11 subunits encoded in the nuclear genome. Investigations over the last 50 years have progressively shed light into the sophistication surrounding COX biogenesis and the regulation of this process, disclosing multiple assembly factors, several redox-regulated processes leading to metal co-factor insertion, regulatory mechanisms to couple synthesis of COX subunits to COX assembly, and the incorporation of COX into respiratory supercomplexes...
September 7, 2017: Seminars in Cell & Developmental Biology
https://www.readbyqxmd.com/read/28853723/ndufaf4-variants-are-associated-with-leigh-syndrome-and-cause-a-specific-mitochondrial-complex-i-assembly-defect
#13
Fabian Baertling, Laura Sánchez-Caballero, Mariël A M van den Brand, Liesbeth T Wintjes, Maaike Brink, Frans A van den Brandt, Callum Wilson, Richard J T Rodenburg, Leo G J Nijtmans
Mitochondrial respiratory chain complex I consists of 44 different subunits and can be subgrouped into three functional modules: the Q-, the P- and the N-module. NDUFAF4 (C6ORF66) is an assembly factor of complex I that associates with assembly intermediates of the Q-module. Via exome sequencing, we identified a homozygous missense variant in a complex I-deficient patient with Leigh syndrome. Supercomplex analysis in patient fibroblasts revealed specifically altered stoichiometry. Detailed assembly analysis of complex I, indicative of all of its assembly routes, showed an accumulation of parts of the P- and the N-module but not the Q-module...
November 2017: European Journal of Human Genetics: EJHG
https://www.readbyqxmd.com/read/28844695/architecture-of-human-mitochondrial-respiratory-megacomplex-i2iii2iv2
#14
Runyu Guo, Shuai Zong, Meng Wu, Jinke Gu, Maojun Yang
The respiratory megacomplex represents the highest-order assembly of respiratory chain complexes, and it allows mitochondria to respond to energy-requiring conditions. To understand its architecture, we examined the human respiratory chain megacomplex-I2III2IV2 (MCI2III2IV2) with 140 subunits and a subset of associated cofactors using cryo-electron microscopy. The MCI2III2IV2 forms a circular structure with the dimeric CIII located in the center, where it is surrounded by two copies each of CI and CIV. Two cytochrome c (Cyt...
September 7, 2017: Cell
https://www.readbyqxmd.com/read/28821616/cox16-protein-is-physically-associated-with-cox1p-assembly-intermediates-and-with-cytochrome-oxidase
#15
Chen-Hsien Su, Alexander Tzagoloff
Mitochondrial cytochrome oxidase (COX) catalyzes the last step in the respiratory pathway. In the yeast Saccharomyces cerevisiae, this inner membrane complex is composed of 11 protein subunits. Expression of COX is assisted by some two dozen ancillary proteins that intercede at different stages of the assembly pathway. One such protein, Cox16p, encoded by COX16, was shown to be essential for the activity and assembly of COX. The function of Cox16p, however, has not been determined. We present evidence that Cox16p is present in Cox1p assembly intermediates and in COX...
September 29, 2017: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/28804536/combined-respiratory-chain-deficiency-and-uqcc2-mutations-in-neonatal-encephalomyopathy-defective-supercomplex-assembly-in-complex-iii-deficiencies
#16
René G Feichtinger, Michaela Brunner-Krainz, Bader Alhaddad, Saskia B Wortmann, Reka Kovacs-Nagy, Tatjana Stojakovic, Wolfgang Erwa, Bernhard Resch, Werner Windischhofer, Sarah Verheyen, Sabine Uhrig, Christian Windpassinger, Felix Locker, Christine Makowski, Tim M Strom, Thomas Meitinger, Holger Prokisch, Wolfgang Sperl, Tobias B Haack, Johannes A Mayr
Vertebrate respiratory chain complex III consists of eleven subunits. Mutations in five subunits either mitochondrial (MT-CYB) or nuclear (CYC1, UQCRC2, UQCRB, and UQCRQ) encoded have been reported. Defects in five further factors for assembly (TTC19, UQCC2, and UQCC3) or iron-sulphur cluster loading (BCS1L and LYRM7) cause complex III deficiency. Here, we report a second patient with UQCC2 deficiency. This girl was born prematurely; pregnancy was complicated by intrauterine growth retardation and oligohydramnios...
2017: Oxidative Medicine and Cellular Longevity
https://www.readbyqxmd.com/read/28794267/coi1-is-a-novel-assembly-factor-of-the-yeast-complex-iii-complex-iv-supercomplex
#17
Ravi K Singhal, Christine Kruse, Juliana Heidler, Valentina Strecker, Klaus Zwicker, Lea Düsterwald, Benedikt Westermann, Johannes M Herrmann, Ilka Wittig, Doron Rapaport
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 in the mitochondrial inner membrane various supramolecular assemblies. 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...
August 9, 2017: Molecular Biology of the Cell
https://www.readbyqxmd.com/read/28790391/deficiency-of-cox7rp-a-mitochondrial-supercomplex-assembly-promoting-factor-lowers-blood-glucose-level-in-mice
#18
Sachiko Shiba, Kazuhiro Ikeda, Kuniko Horie-Inoue, Akitoshi Nakayama, Tomoaki Tanaka, Satoshi Inoue
Mitochondria are essential organelles to efficiently produce ATP by ATP-synthase, which uses a proton-gradient generated by respiratory chain complexes. We previously demonstrated that COX7RP/COX7A2L/SCAF1 is a key molecule that promotes respiratory supercomplex assembly and regulates energy generation. The contribution of COX7RP to metabolic homeostasis, however, remains to be clarified. In the present study, we showed a metabolic phenotype of Cox7rp knockout (Cox7rpKO) mice, which exhibit lower blood glucose levels after insulin or pyruvate injection...
August 8, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28781720/mitochondrial-respiration-in-human-colorectal-and-breast-cancer-clinical-material-is-regulated-differently
#19
Andre Koit, Igor Shevchuk, Lyudmila Ounpuu, Aleksandr Klepinin, Vladimir Chekulayev, Natalja Timohhina, Kersti Tepp, Marju Puurand, Laura Truu, Karoliina Heck, Vahur Valvere, Rita Guzun, Tuuli Kaambre
We conducted quantitative cellular respiration analysis on samples taken from human breast cancer (HBC) and human colorectal cancer (HCC) patients. Respiratory capacity is not lost as a result of tumor formation and even though, functionally, complex I in HCC was found to be suppressed, it was not evident on the protein level. Additionally, metabolic control analysis was used to quantify the role of components of mitochondrial interactosome. The main rate-controlling steps in HBC are complex IV and adenine nucleotide transporter, but in HCC, complexes I and III...
2017: Oxidative Medicine and Cellular Longevity
https://www.readbyqxmd.com/read/28774815/antioxidant-defense-in-quiescent-cells-determines-selectivity-of-electron-transport-chain-inhibition-induced-cell-death
#20
Jan Blecha, Silvia Magalhaes Novais, Katerina Rohlenova, Eliska Novotna, Sandra Lettlova, Sabine Schmitt, Hans Zischka, Jiri Neuzil, Jakub Rohlena
Mitochondrial electron transport chain (ETC) targeting shows a great promise in cancer therapy. It is particularly effective in tumors with high ETC activity where ETC-derived reactive oxygen species (ROS) are efficiently induced. Why modern ETC-targeted compounds are tolerated on the organismal level remains unclear. As most somatic cells are in non-proliferative state, the features associated with the ETC in quiescence could account for some of the specificity observed. Here we report that quiescent cells, despite increased utilization of the ETC and enhanced supercomplex assembly, are less susceptible to cell death induced by ETC disruption when glucose is not limiting...
July 31, 2017: Free Radical Biology & Medicine
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