scholarly journals Arabidopsis thaliana alternative dehydrogenases: a potential therapy for mitochondrial complex I deficiency? Perspectives and pitfalls

2019 ◽  
Vol 14 (1) ◽  
Author(s):  
Alessia Catania ◽  
Arcangela Iuso ◽  
Juliette Bouchereau ◽  
Laura S. Kremer ◽  
Marina Paviolo ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Complex I ◽  
Mitochondrial Diseases ◽  
Mitochondrial Respiratory Chain ◽  
Nadh:Ubiquinone Oxidoreductase ◽  
Sod Activity ◽  
Respiratory Chain Defect ◽  
Human Control ◽  
Initial Hypothesis ◽  
Therapeutic Tools

Abstract Background Complex I (CI or NADH:ubiquinone oxidoreductase) deficiency is the most frequent cause of mitochondrial respiratory chain defect. Successful attempts to rescue CI function by introducing an exogenous NADH dehydrogenase, such as the NDI1 from Saccharomyces cerevisiae (ScNDI1), have been reported although with drawbacks related to competition with CI. In contrast to ScNDI1, which is permanently active in yeast naturally devoid of CI, plant alternative NADH dehydrogenases (NDH-2) support the oxidation of NADH only when the CI is metabolically inactive and conceivably when the concentration of matrix NADH exceeds a certain threshold. We therefore explored the feasibility of CI rescue by NDH-2 from Arabidopsis thaliana (At) in human CI defective fibroblasts. Results We showed that, other than ScNDI1, two different NDH-2 (AtNDA2 and AtNDB4) targeted to the mitochondria were able to rescue CI deficiency and decrease oxidative stress as indicated by a normalization of SOD activity in human CI-defective fibroblasts. We further demonstrated that when expressed in human control fibroblasts, AtNDA2 shows an affinity for NADH oxidation similar to that of CI, thus competing with CI for the oxidation of NADH as opposed to our initial hypothesis. This competition reduced the amount of ATP produced per oxygen atom reduced to water by half in control cells. Conclusions In conclusion, despite their promising potential to rescue CI defects, due to a possible competition with remaining CI activity, plant NDH-2 should be regarded with caution as potential therapeutic tools for human mitochondrial diseases.

scholarly journals LINC00116 codes for a mitochondrial peptide linking respiration and lipid metabolism

2019 ◽  
Vol 116 (11) ◽  
pp. 4940-4945 ◽  
Author(s):  
Anastasia Chugunova ◽  
Elizaveta Loseva ◽  
Pavel Mazin ◽  
Aleksandra Mitina ◽  
Tsimafei Navalayeu ◽  
...  
Keyword(s):  
Complex I ◽  
Noncoding Rna ◽  
Cytochrome B5 ◽  
Chain Complex ◽  
Mitochondrial Respiratory Chain ◽  
Mouse Cell ◽  
Nadh:Ubiquinone Oxidoreductase ◽  
Small Peptides ◽  
Mitochondrial Respiratory Chain Complex ◽  
Cellular Processes

Genes coding for small peptides have been frequently misannotated as long noncoding RNA (lncRNA) genes. Here we have demonstrated that one such transcript is translated into a 56-amino-acid-long peptide conserved in chordates, corroborating the work published while this manuscript was under review. The Mtln peptide could be detected in mitochondria of mouse cell lines and tissues. In line with its mitochondrial localization, lack of the Mtln decreases the activity of mitochondrial respiratory chain complex I. Unlike the integral components and assembly factors of NADH:ubiquinone oxidoreductase, Mtln does not alter its enzymatic activity directly. Interaction of Mtln with NADH-dependent cytochrome b5 reductase stimulates complex I functioning most likely by providing a favorable lipid composition of the membrane. Study of Mtln illuminates the importance of small peptides, whose genes might frequently be misannotated as lncRNAs, for the control of vitally important cellular processes.

scholarly journals Specific features and assembly of the plant mitochondrial complex I revealed by cryo-EM

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Heddy Soufari ◽  
Camila Parrot ◽  
Lauriane Kuhn ◽  
Florent Waltz ◽  
Yaser Hashem
Keyword(s):  
Carbonic Anhydrase ◽  
Complex I ◽  
Mitochondrial Respiratory Chain ◽  
Nadh:Ubiquinone Oxidoreductase ◽  
Mitochondrial Complex I ◽  
Mitochondrial Complex ◽  
Entry Site ◽  
Lipid Complex ◽  
Maturation Factor ◽  
Specific Complex

Abstract Mitochondria are the powerhouses of eukaryotic cells and the site of essential metabolic reactions. Complex I or NADH:ubiquinone oxidoreductase is the main entry site for electrons into the mitochondrial respiratory chain and constitutes the largest of the respiratory complexes. Its structure and composition vary across eukaryote species. However, high resolution structures are available only for one group of eukaryotes, opisthokonts. In plants, only biochemical studies were carried out, already hinting at the peculiar composition of complex I in the green lineage. Here, we report several cryo-electron microscopy structures of the plant mitochondrial complex I. We describe the structure and composition of the plant respiratory complex I, including the ancestral mitochondrial domain composed of the carbonic anhydrase. We show that the carbonic anhydrase is a heterotrimeric complex with only one conserved active site. This domain is crucial for the overall stability of complex I as well as a peculiar lipid complex composed of cardiolipin and phosphatidylinositols. Moreover, we also describe the structure of one of the plant-specific complex I assembly intermediates, lacking the whole PD module, in presence of the maturation factor GLDH. GLDH prevents the binding of the plant specific P1 protein, responsible for the linkage of the PP to the PD module.

scholarly journals Specific features and assembly of the plant mitochondrial complex I revealed by cryo-EM

2020 ◽  
Author(s):  
Heddy Soufari ◽  
Camila Parrot ◽  
Lauriane Kuhn ◽  
Florent Waltz ◽  
Yaser Hashem
Keyword(s):  
Carbonic Anhydrase ◽  
Complex I ◽  
Mitochondrial Respiratory Chain ◽  
Eukaryotic Cells ◽  
Nadh:Ubiquinone Oxidoreductase ◽  
Mitochondrial Complex I ◽  
Mitochondrial Complex ◽  
Entry Site ◽  
Lipid Complex ◽  
Additional Domain

AbstractMitochondria are the powerhouses of eukaryotic cells and the site of essential metabolic reactions. Their main purpose is to maintain the high ATP/ADP ratio that is required to fuel the countless biochemical reactions taking place in eukaryotic cells1. This high ATP/ADP ratio is maintained through oxidative phosphorylation (OXPHOS). Complex I or NADH:ubiquinone oxidoreductase is the main entry site for electrons into the mitochondrial respiratory chain and constitutes the largest of the respiratory complexes2. Its structure and composition varies across eukaryotes species. However, high resolution structures are available only for one group of eukaryotes, opisthokonts3–6. In plants, only biochemical studies were carried out, already hinting the peculiar composition of complex I in the green lineage. Here, we report several cryo-electron microscopy structures of the plant mitochondrial complex I at near-atomic resolution. We describe the structure and composition of the plant complex I including the plant-specific additional domain composed by carbonic anhydrase proteins. We show that the carbonic anhydrase is an heterotrimeric complex with only one conserved active site. This domain is crucial for the overall stability of complex I as well as a peculiar lipid complex composed cardiolipin and phosphatidylinositols. Moreover we also describe the structure of one of the plant-specific complex I assembly intermediate, lacking the whole PD module, in presence of the maturation factor GLDH. GLDH prevents the binding of the plant specific P1 protein, responsible for the linkage of the PP to the PD module. Finally, as the carbonic anhydrase domain is likely to be associated with complex I from numerous other known eukaryotes, we propose that our structure unveils an ancestral-like organization of mitochondrial complex I.

scholarly journals ND3 and ND4L Subunits of Mitochondrial Complex I, Both Nucleus Encoded in Chlamydomonas reinhardtii, Are Required for Activity and Assembly of the Enzyme

2006 ◽  
Vol 5 (9) ◽  
pp. 1460-1467 ◽  
Author(s):  
Pierre Cardol ◽  
Marie Lapaille ◽  
Pierre Minet ◽  
Fabrice Franck ◽  
René F. Matagne ◽  
...  
Keyword(s):  
Enzyme Activity ◽  
Chlamydomonas Reinhardtii ◽  
Complex I ◽  
Nuclear Genome ◽  
Mitochondrial Respiratory Chain ◽  
Nadh:Ubiquinone Oxidoreductase ◽  
Unicellular Green Alga ◽  
Membrane Bound ◽  
Highly Hydrophobic

ABSTRACT Made of more than 40 subunits, the rotenone-sensitive NADH:ubiquinone oxidoreductase (complex I) is the most intricate membrane-bound enzyme of the mitochondrial respiratory chain. In vascular plants, fungi, and animals, at least seven complex I subunits (ND1, -2, -3, -4, -4L, -5, and -6; ND is NADH dehydrogenase) are coded by mitochondrial genes. The role of these highly hydrophobic subunits in the enzyme activity and assembly is still poorly understood. In the unicellular green alga Chlamydomonas reinhardtii, the ND3 and ND4L subunits are encoded in the nuclear genome, and we show here that the corresponding genes, called NUO3 and NUO11, respectively, display features that facilitate their expression and allow the proper import of the corresponding proteins into mitochondria. In particular, both polypeptides show lower hydrophobicity compared to their mitochondrion-encoded counterparts. The expression of the NUO3 and NUO11 genes has been suppressed by RNA interference. We demonstrate that the absence of ND3 or ND4L polypeptides prevents the assembly of the 950-kDa whole complex I and suppresses the enzyme activity. The putative role of hydrophobic ND subunits is discussed in relation to the structure of the complex I enzyme. A model for the assembly pathway of the Chlamydomonas enzyme is proposed.

Mutation m.3395A > G in MT-ND1 leads to variable pathologic manifestations

2020 ◽  
Vol 29 (6) ◽  
pp. 980-989
Author(s):  
Nicolás Gutiérrez Cortés ◽  
Claire Pertuiset ◽  
Elodie Dumon ◽  
Marine Börlin ◽  
Barbara Da Costa ◽  
...  
Keyword(s):  
Complex I ◽  
Mitochondrial Diseases ◽  
Mitochondrial Respiratory Chain ◽  
Functional Study ◽  
Mtdna Mutation ◽  
Wide Range ◽  
Complex I Assembly ◽  
First Time ◽  
Do So

Abstract A non-synonymous mtDNA mutation, m.3395A > G, which changes tyrosine in position 30 to cysteine in p.MT-ND1, was found in several patients with a wide range of clinical phenotypes such as deafness, diabetes and cerebellar syndrome but no Leber’s hereditary optic neuropathy. Although this mutation has already been described, its pathogenicity has not been demonstrated. Here, it was found isolated for the first time, allowing a study to investigate its pathogenicity. To do so, we constructed cybrid cell lines and carried out a functional study to assess the possible consequences of the mutation on mitochondrial bioenergetics. Results obtained demonstrated that this mutation causes an important dysfunction of the mitochondrial respiratory chain with a decrease in both activity and quantity of complex I due to a diminution of p.MT-ND1 quantity. However, no subcomplexes were found in cybrids carrying the mutation, indicating that the quality of the complex I assembly is not affected. Moreover, based on the crystal structure of p.MT-ND1 and the data found in the literature, we propose a hypothesis for the mechanism of the degradation of p.MT-ND1. Our study provides new insights into the pathophysiology of mitochondrial diseases and in particular of MT-ND1 mutations.

scholarly journals Human Ind1, an Iron-Sulfur Cluster Assembly Factor for Respiratory Complex I

2009 ◽  
Vol 29 (22) ◽  
pp. 6059-6073 ◽  
Author(s):  
Alex D. Sheftel ◽  
Oliver Stehling ◽  
Antonio J. Pierik ◽  
Daili J. A. Netz ◽  
Stefan Kerscher ◽  
...  
Keyword(s):  
Complex I ◽  
Mitochondrial Diseases ◽  
Mitochondrial Morphology ◽  
Nadh:Ubiquinone Oxidoreductase ◽  
Activity Levels ◽  
Cluster Assembly ◽  
Respiratory Complex ◽  
Iron Sulfur ◽  
Assembly Factor ◽  
Respiratory Complex I

ABSTRACT Respiratory complex I (NADH:ubiquinone oxidoreductase) is a large mitochondrial inner membrane enzyme consisting of 45 subunits and 8 iron-sulfur (Fe/S) clusters. While complex I dysfunction is the most common reason for mitochondrial diseases, the assembly of complex I and its Fe/S cofactors remains elusive. Here, we identify the human mitochondrial P-loop NTPase, designated huInd1, that is critically required for the assembly of complex I. huInd1 can bind an Fe/S cluster via a conserved CXXC motif in a labile fashion. Knockdown of huInd1 in HeLa cells by RNA interference technology led to strong decreases in complex I protein and activity levels, remodeling of respiratory supercomplexes, and alteration of mitochondrial morphology. In addition, huInd1 depletion resulted in massive decreases in several subunits (NDUFS1, NDUFV1, NDUFS3, and NDUFA13) of the peripheral arm of complex I, with the concomitant appearance of a 450-kDa subcomplex representing part of the membrane arm. By a novel radiolabeling technique, the amount of iron associated with complex I was also shown to reflect the dependence of this enzyme on huInd1 for assembly. Together, these data identify huInd1 as a new assembly factor for human respiratory complex I with a possible role in the delivery of one or more Fe/S clusters to complex I subunits.

Antiulcer and Antioxidant Activity of a Lectin from Mucuna pruriens Seeds on Ethanol- induced Gastropathy: Involvement of Alpha-2 Adrenoceptors and Prostaglandins

2019 ◽  
Vol 25 (12) ◽  
pp. 1430-1439 ◽  
Author(s):  
Isabela Ribeiro Pinto ◽  
Hellíada V. Chaves ◽  
Auriana S. Vasconcelos ◽  
Francisca Clea F de Sousa ◽  
Tatiane Santi-Gadelha ◽  
...  
Keyword(s):  
Lipid Peroxidation ◽  
Acute Toxicity ◽  
Antioxidant Activities ◽  
Mucuna Pruriens ◽  
Toxicity Tests ◽  
Sod Activity ◽  
Tropical Regions ◽  
Mediated Effects ◽  
Menstruation Disorders ◽  
Therapeutic Tools

Ethnopharmacological Relevance:Mucuna pruriens (Mp) belongs to Leguminosae family, it is native of tropical regions and used to treat several maladies such as urinary, neurological, and menstruation disorders, constipation, edema, fever, tuberculosis, ulcers, diabetes, arthritis, dysentery, and cardiovascular diseases. Mp seeds are rich in bioactive compounds, for instance, lectins, a heterogeneous group of proteins and glycoproteins with a potential role as therapeutic tools for several conditions, including gastric disorders. This study investigated the acute toxicity, gastroprotective, and antioxidant activities of a lectin from Mucuna pruriens seeds (MpLec) on ethanol-induced gastropathy model in mice.Materials & Methods:Mice received MpLec (5 or 10 mg/kg; i.v.) and were observed for acute toxicity signs; in another experimental series, mice were pre-treated with MpLec (0.001; 0.01 or 0.1 mg/kg, i.v.), ranitidine (80 mg/kg, p.o.), or saline (0.3 mL/30g, i.v.) before ethanol 99.9% (0.2 mL/animal, p.o.), and euthanized 30 min after ethanol challenge. Macroscopic and microscopic gastric aspects, biochemical parameters (tissue hemoglobin levels, iron-induced lipid peroxidation, GSH content, SOD activity, and gastric mucosal PGE2) were measured. Additionally, pharmacological tools (yohimbine, indomethacin, naloxone, L-NAME) were opportunely used to clarify MpLec gastroprotective mechanisms of action.Results:No toxicity signs nor death were observed at acute toxicity tests. MpLec reduced ethanol-induced gastric damage, edema, and hemorrhagic patches formation, as well as decreased lipid peroxidation, SOD activity, and increased GSH content. Yohimbine and indomethacin prevented MpLec effects, suggesting the involvement of alpha-2 adrenoceptors and prostaglandins in the MpLec-mediated effects.Conclusion:MpLec does not present toxicity signs and shows gastroprotective and antioxidant activities via alpha-2 adrenoceptors and prostaglandins in the ethanol-induced gastropathy model.

Mutants of Chlamydomonas reinhardtii Deficient in Mitochondrial Complex I: Characterization of Two Mutations Affecting the nd1 Coding Sequence

Genetics ◽  
2001 ◽  
Vol 158 (3) ◽  
pp. 1051-1060
Author(s):  
Claire Remacle ◽  
Denis Baurain ◽  
Pierre Cardol ◽  
René F Matagne
Keyword(s):  
Mitochondrial Genome ◽  
Chlamydomonas Reinhardtii ◽  
Complex I ◽  
Slow Growth ◽  
Nadh:Ubiquinone Oxidoreductase ◽  
Sequencing Analysis ◽  
Mitochondrial Complex ◽  
Genetical Analysis ◽  
Complex I Activity

Abstract The mitochondrial rotenone-sensitive NADH:ubiquinone oxidoreductase (complex I) comprises more than 30 subunits, the majority of which are encoded by the nucleus. In Chlamydomonas reinhardtii, only five components of complex I are coded for by mitochondrial genes. Three mutants deprived of complex I activity and displaying slow growth in the dark were isolated after mutagenic treatment with acriflavine. A genetical analysis demonstrated that two mutations (dum20 and dum25) affect the mitochondrial genome whereas the third mutation (dn26) is of nuclear origin. Recombinational analyses showed that dum20 and dum25 are closely linked on the genetic map of the mitochondrial genome and could affect the nd1 gene. A sequencing analysis confirmed this conclusion: dum20 is a deletion of one T at codon 243 of nd1; dum25 corresponds to a 6-bp deletion that eliminates two amino acids located in a very conserved hydrophilic segment of the protein.

scholarly journals Paracoccus denitrificans: a genetically tractable model system for studying respiratory complex I

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Owen D. Jarman ◽  
Olivier Biner ◽  
John J. Wright ◽  
Judy Hirst
Keyword(s):  
Complex I ◽  
Paracoccus Denitrificans ◽  
Model System ◽  
Proton Pumping ◽  
Model Systems ◽  
Metabolic Enzyme ◽  
Nadh:Ubiquinone Oxidoreductase ◽  
Mitochondrial Complex I ◽  
Mitochondrial Complex ◽  
Inner Mitochondrial Membrane

AbstractMitochondrial complex I (NADH:ubiquinone oxidoreductase) is a crucial metabolic enzyme that couples the free energy released from NADH oxidation and ubiquinone reduction to the translocation of four protons across the inner mitochondrial membrane, creating the proton motive force for ATP synthesis. The mechanism by which the energy is captured, and the mechanism and pathways of proton pumping, remain elusive despite recent advances in structural knowledge. Progress has been limited by a lack of model systems able to combine functional and structural analyses with targeted mutagenic interrogation throughout the entire complex. Here, we develop and present the α-proteobacterium Paracoccus denitrificans as a suitable bacterial model system for mitochondrial complex I. First, we develop a robust purification protocol to isolate highly active complex I by introducing a His6-tag on the Nqo5 subunit. Then, we optimize the reconstitution of the enzyme into liposomes, demonstrating its proton pumping activity. Finally, we develop a strain of P. denitrificans that is amenable to complex I mutagenesis and create a catalytically inactive variant of the enzyme. Our model provides new opportunities to disentangle the mechanism of complex I by combining mutagenesis in every subunit with established interrogative biophysical measurements on both the soluble and membrane bound enzymes.

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