351
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Burrage LC, Tang S, Wang J, Donti TR, Walkiewicz M, Luchak JM, Chen LC, Schmitt ES, Niu Z, Erana R, Hunter JV, Graham BH, Wong LJ, Scaglia F. Mitochondrial myopathy, lactic acidosis, and sideroblastic anemia (MLASA) plus associated with a novel de novo mutation (m.8969G>A) in the mitochondrial encoded ATP6 gene. Mol Genet Metab 2014; 113:207-12. [PMID: 25037980 PMCID: PMC4253070 DOI: 10.1016/j.ymgme.2014.06.004] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2014] [Revised: 06/24/2014] [Accepted: 06/24/2014] [Indexed: 11/18/2022]
Abstract
Mitochondrial myopathy, lactic acidosis and sideroblastic anemia (MLASA) is a rare mitochondrial disorder that has previously been associated with mutations in PUS1 and YARS2. In the present report, we describe a 6-year old male with an MLASA plus phenotype. This patient had features of MLASA in the setting of developmental delay, sensorineural hearing loss, epilepsy, agenesis of the corpus callosum, failure to thrive, and stroke-like episodes. Sequencing of the mitochondrial genome identified a novel de novo, heteroplasmic mutation in the mitochondrial DNA (mtDNA) encoded ATP6 gene (m.8969G>A, p.S148N). Whole exome sequencing did not identify mutations or variants in PUS1 or YARS2 or any known nuclear genes that could affect mitochondrial function and explain this phenotype. Studies of fibroblasts derived from the patient revealed a decrease in oligomycin-sensitive respiration, a finding which is consistent with a complex V defect. Thus, this mutation in MT-ATP6 may represent the first mtDNA point mutation associated with the MLASA phenotype.
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Affiliation(s)
- Lindsay C Burrage
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA.
| | - Sha Tang
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA.
| | - Jing Wang
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA.
| | - Taraka R Donti
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA.
| | - Magdalena Walkiewicz
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA.
| | - J Michael Luchak
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA.
| | - Li-Chieh Chen
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA.
| | - Eric S Schmitt
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA.
| | - Zhiyv Niu
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA.
| | - Rodrigo Erana
- Department of Pediatrics, Division of Hematology and Oncology, Baylor College of Medicine, Houston, TX, USA.
| | - Jill V Hunter
- Department of Radiology, Baylor College of Medicine, Houston, TX, USA.
| | - Brett H Graham
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA.
| | - Lee-Jun Wong
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA.
| | - Fernando Scaglia
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA.
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352
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Identification of a prognostic signature for old-age mortality by integrating genome-wide transcriptomic data with the conventional predictors: the Vitality 90+ Study. BMC Med Genomics 2014; 7:54. [PMID: 25213707 PMCID: PMC4167306 DOI: 10.1186/1755-8794-7-54] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Accepted: 09/08/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Prediction models for old-age mortality have generally relied upon conventional markers such as plasma-based factors and biophysiological characteristics. However, it is unknown whether the existing markers are able to provide the most relevant information in terms of old-age survival or whether predictions could be improved through the integration of whole-genome expression profiles. METHODS We assessed the predictive abilities of survival models containing only conventional markers, only gene expression data or both types of data together in a Vitality 90+ study cohort consisting of n = 151 nonagenarians. The all-cause death rate was 32.5% (49 of 151 individuals), and the median follow-up time was 2.55 years. RESULTS Three different feature selection models, the penalized Lasso and Ridge regressions and the C-index boosting algorithm, were used to test the genomic data. The Ridge regression model incorporating both the conventional markers and transcripts outperformed the other models. The multivariate Cox regression model was used to adjust for the conventional mortality prediction markers, i.e., the body mass index, frailty index and cell-free DNA level, revealing that 331 transcripts were independently associated with survival. The final mortality-predicting transcriptomic signature derived from the Ridge regression model was mapped to a network that identified nuclear factor kappa beta (NF-κB) as a central node. CONCLUSIONS Together with the loss of physiological reserves, the transcriptomic predictors centered around NF-κB underscored the role of immunoinflammatory signaling, the control of the DNA damage response and cell cycle, and mitochondrial functions as the key determinants of old-age mortality.
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353
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Ribeiro MPC, Santos AE, Custódio JBA. Mitochondria: the gateway for tamoxifen-induced liver injury. Toxicology 2014; 323:10-8. [PMID: 24881593 DOI: 10.1016/j.tox.2014.05.009] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Revised: 05/14/2014] [Accepted: 05/28/2014] [Indexed: 12/13/2022]
Abstract
Tamoxifen (TAM) is routinely used in the treatment of breast carcinoma. TAM-induced liver injury remains a major concern, as TAM causes hepatic steatosis in a significant number of patients, which can progress toward steatohepatitis. Liver toxicity is generally believed to involve mitochondrial dysfunction and TAM exerts multiple deleterious effects on mitochondria, which may account for the hepatotoxicity observed in patients treated with TAM. Endoxifen (EDX), a key active metabolite of TAM that is being investigated as an alternative to TAM in breast cancer therapy, slightly affects mitochondria in comparison with TAM and this demonstration well correlates with the absence of alterations in the clinical parameters of individuals taking EDX. The steady-state plasma concentrations of TAM and its active metabolites EDX and 4-hydroxytamoxifen (OHTAM) in patients taking TAM are highly variable, reflecting genetic variants of CYP2D6 involved in TAM metabolism. Besides de genetic polymorphisms, the intake of drugs that influence the enzymatic activity of CYP2D6 compromises the therapeutic efficiency of TAM. The knowledge of the impact of the variability of TAM metabolism in the breast cancer treatment explains the discrepant outcomes observed in patients taking TAM, as well as the individual variability of idiosyncratic liver injury and other sides effects observed. Therefore, and contrarily to the clinical use of EDX, the need of therapeutic drug monitoring and a regular assessment of liver function biomarkers should be considered in patients under therapies with TAM. In this review we focus on the mitochondrial effects of TAM and its metabolites and on the role played by mitochondria in the initiating events leading to TAM-induced hepatotoxicity, as well as the clinical implications.
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Affiliation(s)
- Mariana P C Ribeiro
- Center for Neuroscience and Cell Biology, University of Coimbra, 3000-354 Coimbra, Portugal; Laboratory of Biochemistry, Faculty of Pharmacy, University of Coimbra, 3000-548 Coimbra, Portugal
| | - Armanda E Santos
- Center for Neuroscience and Cell Biology, University of Coimbra, 3000-354 Coimbra, Portugal; Laboratory of Biochemistry, Faculty of Pharmacy, University of Coimbra, 3000-548 Coimbra, Portugal
| | - José B A Custódio
- Center for Neuroscience and Cell Biology, University of Coimbra, 3000-354 Coimbra, Portugal; Laboratory of Biochemistry, Faculty of Pharmacy, University of Coimbra, 3000-548 Coimbra, Portugal.
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354
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Du Y, Meng Y, Zhu J, Kang L, Jia X, Guo L, Zhang L, Ye M, Hu L, Zhao X, Gu J, Yang B, Zou H. Quantitative proteomic study of myocardial mitochondria in urea transporter B knockout mice. Proteomics 2014; 14:2072-83. [PMID: 25044461 DOI: 10.1002/pmic.201400123] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Revised: 05/26/2014] [Accepted: 07/04/2014] [Indexed: 11/08/2022]
Abstract
In previous research, we showed that 16-week-old urea transporter B (UT-B) null mice have an atrial-ventricular conduction block, and hypothesized myocardial mitochondrial dysfunction. To investigate the mechanism of this block, we examined the proteomic differences in the myocardial mitochondria of UT-B null and wild-type mice with nanoscale LC-MS/MS. Of 26 proteins clearly downregulated in the UT-B null mice, 15 are involved in complexes I, III, IV, and V of the respiratory chain, which would strongly reduce the activity of the electron transport chain. Excess electrons from complexes I and III pass directly to O2 to generate ROS and deplete ROS-scavenging enzymes. Myocardial intracellular ROS were significantly higher in UT-B null mice than in wild-type mice (p < 0.01), constituting an important cause of oxidative stress injury in the myocardia of UT-B null mice. The mitochondrial membrane potential (ΔΨm) was also lower in UT-B null mice than in wild-type mice (p < 0.05), causing oxidative phosphorylation dysfunction of complex V and insufficient ATP in the myocardial cells of UT-B null mice. HADHA (a trifunctional protein) and HSP60 were also downregulated in the UT-B null myocardial mitochondria. These results confirm that mitochondrial dysfunction underlies the pathogenesis of the atrial-ventricular conduction block in UT-B null mice.
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Affiliation(s)
- Yanwei Du
- Key Laboratory of Pathobiology, Department of Pathophysiology, Ministry of Education, College of Basic Medicine, Jilin University, Changchun, P. R. China
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355
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Graf A, Krebs S, Heininen-Brown M, Zakhartchenko V, Blum H, Wolf E. Genome activation in bovine embryos: Review of the literature and new insights from RNA sequencing experiments. Anim Reprod Sci 2014; 149:46-58. [DOI: 10.1016/j.anireprosci.2014.05.016] [Citation(s) in RCA: 94] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2014] [Revised: 05/09/2014] [Accepted: 05/26/2014] [Indexed: 11/30/2022]
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356
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Involvement of ATP synthase β subunit in chikungunya virus entry into insect cells. Arch Virol 2014; 159:3353-64. [PMID: 25168043 DOI: 10.1007/s00705-014-2210-4] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2013] [Accepted: 08/20/2014] [Indexed: 10/24/2022]
Abstract
Chikungunya virus (CHIKV), the virus responsible for the disease chikungunya fever in humans, is transmitted by Aedes mosquitoes. While significant progress has been made in understanding the process by which CHIKV enters into mammalian cells, far less progress has been made in understanding the CHIKV entry process in insect cells. This study sought to identify mosquito-cell-expressed CHIKV-binding proteins through a combination of virus overlay protein binding assays (VOPBA) and mass spectroscopy. A 50-kDa CHIKV-binding protein was identified as the ATP synthase β subunit (ATPSβ). Co-immunoprecipitation studies confirmed the interaction, and colocalization analysis showed cell-surface and intracellular co-localization between CHIKV and ATPSβ. Both antibody inhibition and siRNA-mediated downregulation experiments targeted to ATPSβ showed a significant reduction in viral entry and virus production. These results suggest that ATPSβ is a CHIKV-binding protein capable of mediating the entry of CHIKV into insect cells.
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357
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Lumish HS, Yang Y, Xia F, Wilson A, Chung WK. The Expanding MEGDEL Phenotype: Optic Nerve Atrophy, Microcephaly, and Myoclonic Epilepsy in a Child with SERAC1 Mutations. JIMD Rep 2014; 16:75-9. [PMID: 24997715 PMCID: PMC4221303 DOI: 10.1007/8904_2014_322] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/27/2013] [Revised: 04/03/2014] [Accepted: 05/20/2014] [Indexed: 01/30/2023] Open
Abstract
The inborn errors of metabolism associated with 3-methylglutaconic aciduria are a diverse group of disorders characterized by the excretion of 3-methylglutaconic and 3-methylglutaric acids in the urine. Mutations in several genes have been identified in association with 3-methylglutaconic aciduria. We describe a patient of Saudi Arabian descent with 3-methylglutaconic aciduria, sensorineural hearing loss, encephalopathy, and Leigh-like pattern on MRI (MEGDEL syndrome), as well as developmental delay and developmental regression, bilateral optic nerve atrophy, microcephaly, and myoclonic epilepsy. The patient had an earlier age of onset of optic atrophy than previously described in other MEGDEL syndrome patients. Whole exome sequencing revealed two loss-of-function mutations in SERAC1 in trans: c.438delC (p.T147Rfs*22) and c.442C>T (p.R148X), confirmed by Sanger sequencing. One of these mutations is novel (c.438delC). This case contributes to refining the MEGDEL phenotype.
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Affiliation(s)
- Heidi S. Lumish
- />College of Physicians and Surgeons, Columbia University, New York, NY USA
| | - Yaping Yang
- />Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX USA
| | - Fan Xia
- />Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX USA
| | - Ashley Wilson
- />Division of Clinical Genetics, New York Presbyterian Hospital, New York, NY USA
| | - Wendy K. Chung
- />Department of Pediatrics and Medicine, Columbia University, New York, NY USA
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358
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Jacobsen MW, Pujolar JM, Gilbert MTP, Moreno-Mayar JV, Bernatchez L, Als TD, Lobon-Cervia J, Hansen MM. Speciation and demographic history of Atlantic eels (Anguilla anguilla and A. rostrata) revealed by mitogenome sequencing. Heredity (Edinb) 2014; 113:432-42. [PMID: 24865601 DOI: 10.1038/hdy.2014.44] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2013] [Revised: 03/14/2014] [Accepted: 03/19/2014] [Indexed: 12/30/2022] Open
Abstract
Processes leading to speciation in oceanic environments without obvious physical barriers remain poorly known. European and American eel (Anguilla anguilla and A. rostrata) spawn in partial sympatry in the Sargasso Sea. Larvae are advected by the Gulf Stream and other currents towards the European/North African and North American coasts, respectively. We analyzed 104 mitogenomes from the two species along with mitogenomes of other Anguilla and outgroup species. We estimated divergence time between the two species to identify major events involved in speciation. We also considered two previously stated hypotheses: one where the ancestral species was present in only one continent but was advected across the Atlantic by ocean current changes and another where population declines during Pleistocene glaciations led to increasing vicariance, facilitating speciation. Divergence time was estimated to ∼3.38 Mya, coinciding with the closure of the Panama Gateway that led to reinforcement of the Gulf Stream. This could have advected larvae towards European/North African coasts, in which case American eel would be expected to be the ancestral species. This scenario could, however, not be unequivocally confirmed by analyses of dN/dS, nucleotide diversity and effective population size estimates. Extended bayesian skyline plots showed fluctuations of effective population sizes and declines during glaciations, and thus also lending support to the importance of vicariance during speciation. There was evidence for positive selection at the ATP6 and possibly ND5 genes, indicating a role in speciation. The findings suggest an important role of ocean current changes in speciation of marine organisms.
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Affiliation(s)
- M W Jacobsen
- Department of Bioscience, Aarhus University, Aarhus C, Denmark
| | - J M Pujolar
- Department of Bioscience, Aarhus University, Aarhus C, Denmark
| | - M T P Gilbert
- Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, Copenhagen, Denmark
| | - J V Moreno-Mayar
- Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, Copenhagen, Denmark
| | - L Bernatchez
- Département de Biologie, Institut de Biologie Intégrative et des Systèmes (IBIS), Pavillon Charles-Eugène-Marchand, Québec, Québec Canada
| | - T D Als
- 1] Department of Biomedicine-Human Genetics, Aarhus University, Aarhus C, Denmark [2] National Institute of Aquatic Resources, Section for Marine Living Resources, Technical University of Denmark, Silkeborg, Denmark
| | - J Lobon-Cervia
- Javier Lobon-Cervia, National Museum of Natural Sciences (CSIC), C/ José Gutierrez Abascal, Madrid, Spain
| | - M M Hansen
- Department of Bioscience, Aarhus University, Aarhus C, Denmark
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359
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Busija DW, Katakam PV. Mitochondrial mechanisms in cerebral vascular control: shared signaling pathways with preconditioning. J Vasc Res 2014; 51:175-89. [PMID: 24862206 PMCID: PMC4149841 DOI: 10.1159/000360765] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2013] [Accepted: 02/19/2014] [Indexed: 12/14/2022] Open
Abstract
Mitochondrial-initiated events protect the neurovascular unit against lethal stress via a process called preconditioning, which independently promotes changes in cerebrovascular tone through shared signaling pathways. Activation of adenosine triphosphate (ATP)-dependent potassium channels on the inner mitochondrial membrane (mitoKATP channels) is a specific and dependable way to induce protection of neurons, astroglia, and cerebral vascular endothelium. Through the opening of mitoKATP channels, mitochondrial depolarization leads to activation of protein kinases and transient increases in cytosolic calcium (Ca(2+)) levels that activate terminal mechanisms that protect the neurovascular unit against lethal stress. The release of reactive oxygen species from mitochondria has similar protective effects. Signaling elements of the preconditioning pathways also are involved in the regulation of vascular tone. Activation of mitoKATP channels in cerebral arteries causes vasodilation, with cell-specific contributions from the endothelium, vascular smooth muscles, and nerves. Preexisting chronic conditions, such as insulin resistance and/or diabetes, prevent preconditioning and impair relaxation to mitochondrial-centered responses in cerebral arteries. Surprisingly, mitochondrial activation after anoxic or ischemic stress appears to protect cerebral vascular endothelium and promotes the restoration of blood flow; therefore, mitochondria may represent an important, but underutilized target in attenuating vascular dysfunction and brain injury in stroke patients.
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Affiliation(s)
- David W Busija
- Department of Pharmacology, Tulane University School of Medicine, New Orleans, La., USA
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360
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Zhao J, Yang D, Zhao Y, Yang XJ, Wang YY, Wu B. Anion-Coordination-Induced Turn-On Fluorescence of an Oligourea-Functionalized Tetraphenylethene in a Wide Concentration Range. Angew Chem Int Ed Engl 2014; 53:6632-6. [DOI: 10.1002/anie.201402169] [Citation(s) in RCA: 140] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2014] [Indexed: 11/07/2022]
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361
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Zhao J, Yang D, Zhao Y, Yang XJ, Wang YY, Wu B. Anion-Coordination-Induced Turn-On Fluorescence of an Oligourea-Functionalized Tetraphenylethene in a Wide Concentration Range. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201402169] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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362
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The molecular mechanism for effects of TiN coating on NiTi alloy on endothelial cell function. Biomaterials 2014; 35:6195-205. [PMID: 24818882 DOI: 10.1016/j.biomaterials.2014.04.069] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Accepted: 04/17/2014] [Indexed: 12/17/2022]
Abstract
The aim of this study is to systematically investigate the molecular mechanism of different effects of nickel titanium (NiTi) alloy surface and titanium nitride (TiN) coating on endothelial cell function. Release of nickel (Ni) ion from bare and TiN-coated NiTi alloys and proliferation of endothelial cells on the two materials were evaluated, and then influence of the two materials on cellular protein expression profiles was investigated by proteomic technology. Subsequently, proteomic data were analyzed with bioinformatics analyses and further validated using a series of biological experiments. Results showed that although the two materials did not affect cell proliferation, the Ni ions released from bare NiTi alloy generated inhibition on pathways associated with actin cytoskeleton, focal adhesion, energy metabolism, inflammation, and amino acid metabolism. In comparison, TiN coating not only effectively prevented release of Ni ions from NiTi alloy, but also promoted actin cytoskeleton and focal adhesion formation, increased energy metabolism, enhanced regulation of inflammation, and promoted amino acid metabolism. Furthermore, the two processes, "the initial mediation of adsorbed serum protein layer to endothelial cell adhesion and growth on the two materials" from our previous study, and "the following action of the two materials on cellular protein expression profile", were linked up and comprehensively analyzed. It was found that in stage of cell adhesion (within 4 h), release of Ni ions from bare NiTi alloy was very low, and the activation of adsorbed proteins to cell adhesion and growth related biological pathways (such as regulation of actin cytoskeleton, and focal adhesion pathways) was almost as same as TiN-coated NiTi alloy. This indicated that the released Ni ions did not affect the mediation of adsorbed proteins to endothelial cell adhesion. However, in stage of cell growth and proliferation, the release of Ni ions from bare NiTi alloy increased with time and reached a higher level, which inhibited endothelial cell function at molecular level, whereas TiN coating improved endothelial cell function.
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363
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Antoniel M, Giorgio V, Fogolari F, Glick GD, Bernardi P, Lippe G. The oligomycin-sensitivity conferring protein of mitochondrial ATP synthase: emerging new roles in mitochondrial pathophysiology. Int J Mol Sci 2014; 15:7513-36. [PMID: 24786291 PMCID: PMC4057687 DOI: 10.3390/ijms15057513] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2014] [Revised: 04/18/2014] [Accepted: 04/21/2014] [Indexed: 01/08/2023] Open
Abstract
The oligomycin-sensitivity conferring protein (OSCP) of the mitochondrial F(O)F1 ATP synthase has long been recognized to be essential for the coupling of proton transport to ATP synthesis. Located on top of the catalytic F1 sector, it makes stable contacts with both F1 and the peripheral stalk, ensuring the structural and functional coupling between F(O) and F1, which is disrupted by the antibiotic, oligomycin. Recent data have established that OSCP is the binding target of cyclophilin (CyP) D, a well-characterized inducer of the mitochondrial permeability transition pore (PTP), whose opening can precipitate cell death. CyPD binding affects ATP synthase activity, and most importantly, it decreases the threshold matrix Ca²⁺ required for PTP opening, in striking analogy with benzodiazepine 423, an apoptosis-inducing agent that also binds OSCP. These findings are consistent with the demonstration that dimers of ATP synthase generate Ca²⁺-dependent currents with features indistinguishable from those of the PTP and suggest that ATP synthase is directly involved in PTP formation, although the underlying mechanism remains to be established. In this scenario, OSCP appears to play a fundamental role, sensing the signal(s) that switches the enzyme of life in a channel able to precipitate cell death.
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Affiliation(s)
- Manuela Antoniel
- Department of Biomedical Sciences, University of Padova, via Ugo Bassi 58/B, 35121 Padua, Italy.
| | - Valentina Giorgio
- Department of Biomedical Sciences, University of Padova, via Ugo Bassi 58/B, 35121 Padua, Italy.
| | - Federico Fogolari
- Department of Biomedical Sciences, University of Udine, p.le Kolbe, 33100 Udine, Italy.
| | - Gary D Glick
- Department of Chemistry, Graduate Program in Immunology, University of Michigan, Ann Arbor, MI 48109, USA.
| | - Paolo Bernardi
- Department of Biomedical Sciences, University of Padova, via Ugo Bassi 58/B, 35121 Padua, Italy.
| | - Giovanna Lippe
- Department of Food Science, University of Udine, via Sondrio 2/A, 33100 Udine, Italy.
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364
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Diodato D, Invernizzi F, Lamantea E, Fagiolari G, Parini R, Menni F, Parenti G, Bollani L, Pasquini E, Donati MA, Cassandrini D, Santorelli FM, Haack TB, Prokisch H, Ghezzi D, Lamperti C, Zeviani M. Common and Novel TMEM70 Mutations in a Cohort of Italian Patients with Mitochondrial Encephalocardiomyopathy. JIMD Rep 2014; 15:71-8. [PMID: 24740313 PMCID: PMC4270871 DOI: 10.1007/8904_2014_300] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Revised: 01/31/2014] [Accepted: 02/07/2014] [Indexed: 12/21/2022] Open
Abstract
ATP synthase or complex V (cV) of the oxidative phosphorylation system is responsible for the production of ATP, dissipating the electrochemical gradient generated by the mitochondrial respiratory chain. In addition to maternally transmitted cV dysfunction caused by mutations in mtDNA genes (MT-ATP6 or MT-ATP8), encoding cV subunits, recessive mutations in the nuclear TMEM70 are the most frequent cause of ATP synthase deficiency.We report on a cohort of ten Italian patients presenting with neonatal lactic acidosis, respiratory distress, hypotonia, cardiomyopathy and psychomotor delay and harbouring mutations in TMEM70, including the common splice mutation and four novel variants. TMEM70 protein was virtually absent in all tested TMEM70 patients' specimens.The exact function of TMEM70 is not known, but it is considered to impact on cV assembly since TMEM70 mutations have been associated with isolated cV activity reduction. We detected a clear cV biochemical defect in TMEM70 patients' fibroblasts, whereas the assay was not reliable in frozen muscle. Nevertheless, the evaluation of the amount of holocomplexes in patients with TMEM70 mutations showed a nearly absent cV in muscles and a strong decrease of cV with accumulation of sub-assembly species in fibroblasts. In our cohort we found not only cV deficiencies but also impairment of other OXPHOS complexes. By ultrastructural analysis of muscle tissue from one patient with isolated cV deficiency, we found a severely impaired mitochondrial morphology with loss of the cristae. These findings indicate that cV impairment could indirectly alter other respiratory chain complex activities by disrupting the mitochondrial cristae structure.
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Affiliation(s)
- Daria Diodato
- />Unit of Molecular Neurogenetics, Fondazione Istituto Neurologico “Carlo Besta”, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), via Temolo 4, 20126 Milan, Italy
| | - Federica Invernizzi
- />Unit of Molecular Neurogenetics, Fondazione Istituto Neurologico “Carlo Besta”, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), via Temolo 4, 20126 Milan, Italy
| | - Eleonora Lamantea
- />Unit of Molecular Neurogenetics, Fondazione Istituto Neurologico “Carlo Besta”, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), via Temolo 4, 20126 Milan, Italy
| | - Gigliola Fagiolari
- />Neuromuscular Unit, Department of Neurology, Centro Dino Ferrari, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, University of Milan, 20122 Milan, Italy
| | - Rossella Parini
- />Unit of Metabolic Disorders, Department of Pediatrics, Foundation MBBM/San Gerardo University Hospital, 20900 Monza, Italy
| | - Francesca Menni
- />Pediatric Clinic, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, University of Milan, 20122 Milan, Italy
| | - Giancarlo Parenti
- />Department of Metabolic Diseases, University of Naples “Federico II”, 80138 Naples, Italy
| | - Lina Bollani
- />Neonatal Intensive Care Unit, Fondazione IRCCS Policlinico San Matteo, 27100 Pavia, Italy
| | - Elisabetta Pasquini
- />Unit of Metabolic and Muscular Diseases, Meyer Children Hospital, 50132 Florence, Italy
| | - Maria A. Donati
- />Unit of Metabolic and Muscular Diseases, Meyer Children Hospital, 50132 Florence, Italy
| | | | | | - Tobias B. Haack
- />Institute of Human Genetics, Technical University, 81675 Munich, Germany
- />Helmholtz Zentrum München, 81675 Munich, Germany
| | - Holger Prokisch
- />Institute of Human Genetics, Technical University, 81675 Munich, Germany
- />Helmholtz Zentrum München, 81675 Munich, Germany
| | - Daniele Ghezzi
- />Unit of Molecular Neurogenetics, Fondazione Istituto Neurologico “Carlo Besta”, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), via Temolo 4, 20126 Milan, Italy
| | - Costanza Lamperti
- />Unit of Molecular Neurogenetics, Fondazione Istituto Neurologico “Carlo Besta”, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), via Temolo 4, 20126 Milan, Italy
| | - Massimo Zeviani
- />Unit of Molecular Neurogenetics, Fondazione Istituto Neurologico “Carlo Besta”, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), via Temolo 4, 20126 Milan, Italy
- />Mitochondrial Biology Unit, MRC, Wellcome Trust/MRC Building, Hills Road, CB2 0XY Cambridge, UK
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365
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Ghaffarpour M, Mahdian R, Fereidooni F, Kamalidehghan B, Moazami N, Houshmand M. The mitochondrial ATPase6 gene is more susceptible to mutation than the ATPase8 gene in breast cancer patients. Cancer Cell Int 2014; 14:21. [PMID: 24588805 PMCID: PMC3942513 DOI: 10.1186/1475-2867-14-21] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2013] [Accepted: 02/20/2014] [Indexed: 12/15/2022] Open
Abstract
Background Breast cancer is the most common malignancy in women throughout the world. Mitochondria play important roles in cellular energy production, free radical generation and apoptosis. Identification of mitochondrial DNA mutations and/or polymorphisms as cancer biomarkers is rapidly developing in molecular oncology research. Methods In this study, the DNA alterations of the mitochondrial ATPase 6 and 8 genes were investigated in 49 breast cancer patients using PCR amplification and direct DNA sequencing on mtDNA. A possible association between these variants and tumorigenesis was assessed. Furthermore, the impact of non-synonymous substitutions on the amino acid sequence was evaluated using the PolyPhen-2 software. Results Twenty eight distinct somatic mitochondrial DNA variants were detected in tumor tissues but not in the corresponding adjacent non-tumor tissues. Among these variants, 9 were observed for the first time in breast cancer patients. The mtDNA variants of A8384 (T7A), T8567C (I14T), G8572A (G16S), A9041G (H172R) and G9055A (A177T) showed the most significant effects probably due to damaging changes to the resulting protein. Furthermore, non-synonymous amino acid changing variants were more frequent in the ATPase6 gene compared to the ATPase8 gene. Conclusion Our results showed that the ATPase6 gene is more susceptible to variations in breast cancer and may play an important role in tumorigenesis by changing the energy metabolism level in cancer cells.
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Affiliation(s)
| | | | | | | | | | - Massoud Houshmand
- Medical Genetics Department, National Institute for Genetic Engineering & Biotechnology, Tehran, Iran.
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366
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Magdeldin S, Yamamoto K, Yoshida Y, Xu B, Zhang Y, Fujinaka H, Yaoita E, Yates JR, Yamamoto T. Deep proteome mapping of mouse kidney based on OFFGel prefractionation reveals remarkable protein post- translational modifications. J Proteome Res 2014; 13:1636-46. [PMID: 24495006 PMCID: PMC3993965 DOI: 10.1021/pr401122m] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
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Performing a comprehensive
nonbiased proteome analysis is an extraordinary
challenge due to sample complexity and wide dynamic range, especially
in eukaryotic tissues. Thus, prefractionation steps conducted prior
to mass spectrometric analysis are critically important to reduce
complex biological matrices and allow in-depth analysis. Here we demonstrated
the use of OFFGel prefractionation to identify more low abundant and
hydrophobic proteins than in a nonfractionated sample. Moreover, OFFGel
prefractionation of a kidney protein sample was able to unveil protein
functional relevance by detecting PTMs, especially when prefractionation
was augmented with a targeted enrichment strategy such as TiO2 phospho-enrichment. The OFFGel-TiO2 combination
used in this study was comparable to other global phosphoproteomics
approaches (SCX-TiO2, ERLIC-TiO2, or HILIC-TiO2). The detailed mouse kidney proteome with the phosphopeptide
enrichment presented here serves as a useful platform for a better
understanding of how the renal protein modification machinery works
and, ultimately, will contribute to our understanding of pathological
processes as well as normal physiological renal functions.
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Affiliation(s)
- Sameh Magdeldin
- Department of Structural Pathology, Institute of Nephrology, Graduate School of Medical and Dental Sciences, Niigata University , Niigata, Japan
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367
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HEJZLAROVÁ K, MRÁČEK T, VRBACKÝ M, KAPLANOVÁ V, KARBANOVÁ V, NŮSKOVÁ H, PECINA P, HOUŠTĚK J. Nuclear Genetic Defects of Mitochondrial ATP Synthase. Physiol Res 2014; 63:S57-71. [DOI: 10.33549/physiolres.932643] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Disorders of ATP synthase, the key enzyme of mitochondrial energy provision belong to the most severe metabolic diseases presenting as early-onset mitochondrial encephalo-cardiomyopathies. Up to now, mutations in four nuclear genes were associated with isolated deficiency of ATP synthase. Two of them, ATP5A1 and ATP5E encode enzyme’s structural subunits α and ε, respectively, while the other two ATPAF2 and TMEM70 encode specific ancillary factors that facilitate the biogenesis of ATP synthase. All these defects share a similar biochemical phenotype with pronounced decrease in the content of fully assembled and functional ATP synthase complex. However, substantial differences can be found in their frequency, molecular mechanism of pathogenesis, clinical manifestation as well as the course of the disease progression. While for TMEM70 the number of reported patients as well as spectrum of the mutations is steadily increasing, mutations in ATP5A1, ATP5E and ATPAF2 genes are very rare. Apparently, TMEM70 gene is highly prone to mutagenesis and this type of a rare mitochondrial disease has a rather frequent incidence. Here we present overview of individual reported cases of nuclear mutations in ATP synthase and discuss, how their analysis can improve our understanding of the enzyme biogenesis.
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Affiliation(s)
| | | | | | | | | | | | | | - J. HOUŠTĚK
- Department of Bioenergetics, Institute of Physiology Academy of Sciences of the Czech Republic, Prague, Czech Republic
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368
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Nesci S, Ventrella V, Trombetti F, Pirini M, Pagliarani A. The mitochondrial F1FO-ATPase desensitization to oligomycin by tributyltin is due to thiol oxidation. Biochimie 2014; 97:128-37. [DOI: 10.1016/j.biochi.2013.10.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2013] [Accepted: 10/03/2013] [Indexed: 11/15/2022]
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369
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Blanco-Grau A, Bonaventura-Ibars I, Coll-Cantí J, Melià MJ, Martinez R, Martínez-Gallo M, Andreu AL, Pinós T, García-Arumí E. Identification and biochemical characterization of the novel mutation m.8839G>C in the mitochondrial ATP6 gene associated with NARP syndrome. GENES BRAIN AND BEHAVIOR 2013; 12:812-20. [PMID: 24118886 DOI: 10.1111/gbb.12089] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Revised: 09/25/2013] [Accepted: 09/30/2013] [Indexed: 12/21/2022]
Abstract
Mutations in the ATP6 gene are reported to be associated with Leber hereditary optic neuropathy, bilateral striatal necrosis, coronary atherosclerosis risk and neuropathy, ataxia and retinitis pigmentosa (NARP)/maternally inherited Leigh syndromes. Here, we present a patient with NARP syndrome, in whom a previously undescribed mutation was detected in the ATP6 gene: m.8839G>C. Several observations support the concept that m.8839G>C is pathogenically involved in the clinical phenotype of this patient: (1) the mutation was heteroplasmic in muscle; (2) mutation load was higher in the symptomatic patient than in the asymptomatic carriers; (3) cybrids carrying this mutation presented lower cell proliferation, increased mitochondrial DNA (mtDNA) copy number, increased steady-state OxPhos protein levels and decreased mitochondrial membrane potential with respect to isogenic wild-type cybrids; (4) this change was not observed in 2959 human mtDNAs from different mitochondrial haplogroups; (5) the affected amino acid was conserved in all the ATP6 sequences analyzed; and (6) using in silico prediction, the mutation was classified as 'probably damaging'. However, measurement of ATP synthesis showed no differences between wild-type and mutated cybrids. Thus, we suggest that m.8839G>C may lower the efficiency between proton translocation within F0 and F1 rotation, required for ATP synthesis. Further experiments are needed to fully characterize the molecular mechanisms involved in m.8839G>C pathogenicity.
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Affiliation(s)
- A Blanco-Grau
- Departament de Patología Mitocondrial i Neuromuscular, Universitari Vall d'Hebron Institut de Recerca (VHIR), Universitat Autònoma de Barcelona, Barcelona
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370
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Habersetzer J, Larrieu I, Priault M, Salin B, Rossignol R, Brèthes D, Paumard P. Human F1F0 ATP synthase, mitochondrial ultrastructure and OXPHOS impairment: a (super-)complex matter? PLoS One 2013; 8:e75429. [PMID: 24098383 PMCID: PMC3788808 DOI: 10.1371/journal.pone.0075429] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2013] [Accepted: 08/14/2013] [Indexed: 01/18/2023] Open
Abstract
Mitochondrial morphogenesis is a key process of cell physiology. It is essential for the proper function of this double membrane-delimited organelle, as it ensures the packing of the inner membrane in a very ordered pattern called cristae. In yeast, the mitochondrial ATP synthase is able to form dimers that can assemble into oligomers. Two subunits (e and g) are involved in this supramolecular organization. Deletion of the genes encoding these subunits has no effect on the ATP synthase monomer assembly or activity and only affects its dimerization and oligomerization. Concomitantly, the absence of subunits e and g and thus, of ATP synthase supercomplexes, promotes the modification of mitochondrial ultrastructure suggesting that ATP synthase oligomerization is involved in cristae morphogenesis. We report here that in mammalian cells in culture, the shRNA-mediated down-regulation of subunits e and g affects the stability of ATP synthase and results in a 50% decrease of the available functional enzyme. Comparable to what was shown in yeast, when subunits e and g expression are repressed, ATP synthase dimers and oligomers are less abundant when assayed by native electrophoresis. Unexpectedly, mammalian ATP synthase dimerization/oligomerization impairment has functional consequences on the respiratory chain leading to a decrease in OXPHOS activity. Finally these structural and functional alterations of the ATP synthase have a strong impact on the organelle itself leading to the fission of the mitochondrial network and the disorganization of mitochondrial ultrastructure. Unlike what was shown in yeast, the impairment of the ATP synthase oligomerization process drastically affects mitochondrial ATP production. Thus we propose that mutations or deletions of genes encoding subunits e and g may have physiopathological implications.
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Affiliation(s)
- Johann Habersetzer
- Laboratoire des Systèmes Transducteurs d'Energie et Morphologie Mitochondriale, Université Bordeaux Segalen, IBGC, UMR 5095, Bordeaux, France ; CNRS, IBGC, UMR 5095, Bordeaux, France
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371
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Koeda S, Umezaki K, Sumino A, Noji T, Ikeda A, Yamamoto Y, Dewa T, Taga K, Nango M, Tanaka T, Mizuno T. Creation of cross-linked bilayer membranes that can incorporate membrane proteins from oligo-Asp-based peptide gemini surfactants. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:11695-11704. [PMID: 23944736 DOI: 10.1021/la401566h] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
We designed novel bilayer-forming amphiphiles based on the cyclic oligo-Asp-based peptide gemini (PG) surfactants cr-D2C12 and cr-D3C12, which consist of -Cys(Asp)nCys- (n = 2 or 3) as a core peptide and two Cys residues containing a dodecylamidomethyl group. Dynamic light scattering and transmission electron microscopy measurements revealed the formation of spherical bilayer membranes that could incorporate the light-harvesting antenna complex 2 (LH2) from Rhodopseudomonas acidophila . Furthermore, this proteoliposome-like conjugate could be assembled onto cationized glass and mica to form planar bilayer membranes incorporating LH2. Using atomic force microscopy, we observed LH2 protruding (ca. 1.2-1.5 nm) from flat terraces of the planar bilayer membranes formed from cr-D2C12 or cr-D3C12. Thus, our designed PG surfactants are a new class of bilayer-forming amphiphiles that may be applied to the study of various membrane proteins.
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Affiliation(s)
- Shuhei Koeda
- Graduate School of Engineering, Nagoya Institute of Technology , Gokiso-cho, Showa-ku, Nagoya, Aichi 466-8555, Japan
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372
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Tort F, García-Silva MT, Ferrer-Cortès X, Navarro-Sastre A, Garcia-Villoria J, Coll MJ, Vidal E, Jiménez-Almazán J, Dopazo J, Briones P, Elpeleg O, Ribes A. Exome sequencing identifies a new mutation in SERAC1 in a patient with 3-methylglutaconic aciduria. Mol Genet Metab 2013; 110:73-7. [PMID: 23707711 DOI: 10.1016/j.ymgme.2013.04.021] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2013] [Accepted: 04/29/2013] [Indexed: 12/11/2022]
Abstract
3-Methylglutaconic aciduria (3-MGA-uria) is a heterogeneous group of syndromes characterized by an increased excretion of 3-methylglutaconic and 3-methylglutaric acids. Five types of 3-MGA-uria (I to V) with different clinical presentations have been described. Causative mutations in TAZ, OPA3, DNAJC19, ATP12, ATP5E, and TMEM70 have been identified. After excluding the known genetic causes of 3-MGA-uria we used exome sequencing to investigate a patient with Leigh syndrome and 3-MGA-uria. We identified a homozygous variant in SERAC1 (c.202C>T; p.Arg68*), that generates a premature stop codon at position 68 of SERAC1 protein. Western blot analysis in patient's fibroblasts showed a complete absence of SERAC1 that was consistent with the prediction of a truncated protein and supports the pathogenic role of the mutation. During the course of this project a parallel study identified mutations in SERAC1 as the genetic cause of the disease in 15 patients with MEGDEL syndrome, which was compatible with the clinical and biochemical phenotypes of the patient described here. In addition, our patient developed microcephaly and optic atrophy, two features not previously reported in MEGDEL syndrome. We highlight the usefulness of exome sequencing to reveal the genetic bases of human rare diseases even if only one affected individual is available.
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Affiliation(s)
- Frederic Tort
- Secció d'Errors Congènits del Metabolisme, Servei de Bioquímica i Genètica Molecular, Hospital Clinic, IDIBAPS, 08028, Barcelona, Spain
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373
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Modifiers of the oligomycin sensitivity of the mitochondrial F1F0-ATPase. Mitochondrion 2013; 13:312-9. [DOI: 10.1016/j.mito.2013.04.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Revised: 04/08/2013] [Accepted: 04/09/2013] [Indexed: 02/02/2023]
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374
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Alterations in c-Myc phenotypes resulting from dynamin-related protein 1 (Drp1)-mediated mitochondrial fission. Cell Death Dis 2013; 4:e670. [PMID: 23764851 PMCID: PMC3702284 DOI: 10.1038/cddis.2013.201] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The c-Myc (Myc) oncoprotein regulates numerous phenotypes pertaining to cell mass, survival and metabolism. Glycolysis, oxidative phosphorylation (OXPHOS) and mitochondrial biogenesis are positively controlled by Myc, with myc−/− rat fibroblasts displaying atrophic mitochondria, structural and functional defects in electron transport chain (ETC) components, compromised OXPHOS and ATP depletion. However, while Myc influences mitochondrial structure and function, it is not clear to what extent the reverse is true. To test this, we induced a state of mitochondrial hyper-fission in rat fibroblasts by de-regulating Drp1, a dynamin-like GTPase that participates in the terminal fission process. The mitochondria from these cells showed reduced mass and interconnectivity, a paucity of cristae, a marked reduction in OXPHOS and structural and functional defects in ETC Complexes I and V. High rates of abortive mitochondrial fusion were observed, likely reflecting ongoing, but ultimately futile, attempts to normalize mitochondrial mass. Cellular consequences included reduction of cell volume, ATP depletion and activation of AMP-dependent protein kinase. In response to Myc deregulation, apoptosis was significantly impaired both in the absence and presence of serum, although this could be reversed by increasing ATP levels by pharmacologic means. The current work demonstrates that enforced mitochondrial fission closely recapitulates a state of Myc deficiency and that mitochondrial integrity and function can affect Myc-regulated cellular behaviors. The low intracellular ATP levels that are frequently seen in some tumors as a result of inadequate vascular perfusion could favor tumor survival by countering the pro-apoptotic tendencies of Myc overexpression.
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375
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Liu ZH, Yu LP, Xu T, Zhang XW, Yuan YQ, Xiao YB, Li J, Hao YC, Zhao YP, Wang XF. Abnormal lipid metabolism down-regulates adenosine triphosphate synthase β-subunit protein expression in corpus cavernosum smooth musclein vitroandin vivo. Andrologia 2013; 46:487-94. [PMID: 23635034 DOI: 10.1111/and.12105] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/07/2013] [Indexed: 12/01/2022] Open
Affiliation(s)
- Z-H Liu
- Department of Urology, Peking University People's Hospital, Beijing, China
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376
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Bisetto E, Comelli M, Salzano AM, Picotti P, Scaloni A, Lippe G, Mavelli I. Proteomic analysis of F1F0-ATP synthase super-assembly in mitochondria of cardiomyoblasts undergoing differentiation to the cardiac lineage. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2013; 1827:807-16. [PMID: 23587863 DOI: 10.1016/j.bbabio.2013.04.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2013] [Revised: 03/28/2013] [Accepted: 04/05/2013] [Indexed: 02/06/2023]
Abstract
Mitochondria are essential organelles with multiple functions, especially in energy metabolism. An increasing number of data highlighted their role for cellular differentiation processes. We investigated differences in ATP synthase supra-molecular organization occurring in H9c2 cardiomyoblasts in the course of cardiac-like differentiation, along with ATP synthase biogenesis and maturation of mitochondrial cristae morphology. Using BN-PAGE analysis combined with one-step mild detergent extraction from mitochondria, a significant increase in dimer/monomer ratio was observed, indicating a distinct rise in the stability of the enzyme super-assembly. Remarkably, sub-stoichiometric mean values for ATP synthase subunit e were determined in both parental and cardiac-like H9c2 by an MS-based quantitative proteomics approach. This indicates a similar high proportion of complex molecules lacking subunit e in both cell types, and suggests a minor contribution of this component in the observed changes. 2D BN-PAGE/immunoblotting analysis and MS/MS analysis on single BN-PAGE band showed that the amount of inhibitor protein IF1 bound within the ATP synthase complexes increased in cardiac-like H9c2 and appeared greater in the dimer. In concomitance, a consistent improvement of enzyme activity, measured as both ATP synthesis and ATP hydrolysis rate, was observed, despite the increase of bound IF1 evocative of a greater inhibitory effect on the enzyme ATPase activity. The results suggest i) a role for IF1 in promoting dimer stabilization and super-assembly in H9c2 with physiological IF1 expression levels, likely unveiled by the fact that the contacts through accessory subunit e appear to be partially destabilized, ii) a link between dimer stabilization and enzyme activation.
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Affiliation(s)
- Elena Bisetto
- Department of Medical and Biological Sciences, University of Udine, Udine, Italy
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377
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Kohzuma K, Dal Bosco C, Meurer J, Kramer DM. Light- and metabolism-related regulation of the chloroplast ATP synthase has distinct mechanisms and functions. J Biol Chem 2013; 288:13156-63. [PMID: 23486473 DOI: 10.1074/jbc.m113.453225] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The chloroplast CF0-CF1-ATP synthase (ATP synthase) is activated in the light and inactivated in the dark by thioredoxin-mediated redox modulation of a disulfide bridge on its γ subunit. The activity of the ATP synthase is also fine-tuned during steady-state photosynthesis in response to metabolic changes, e.g. altering CO2 levels to adjust the thylakoid proton gradient and thus the regulation of light harvesting and electron transfer. The mechanism of this fine-tuning is unknown. We test here the possibility that it also involves redox modulation. We found that modifying the Arabidopsis thaliana γ subunit by mutating three highly conserved acidic amino acids, D211V, E212L, and E226L, resulted in a mutant, termed mothra, in which ATP synthase which lacked light-dark regulation had relatively small effects on maximal activity in vivo. In situ equilibrium redox titrations and thiol redox-sensitive labeling studies showed that the γ subunit disulfide/sulfhydryl couple in the modified ATP synthase has a more reducing redox potential and thus remains predominantly oxidized under physiological conditions, implying that the highly conserved acidic residues in the γ subunit influence thiol redox potential. In contrast to its altered light-dark regulation, mothra retained wild-type fine-tuning of ATP synthase activity in response to changes in ambient CO2 concentrations, indicating that the light-dark- and metabolic-related regulation occur through different mechanisms, possibly via small molecule allosteric effectors or covalent modification.
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Affiliation(s)
- Kaori Kohzuma
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
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378
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Regulation of mitochondrial FoF1ATPase activity by Sirt3-catalyzed deacetylation and its deficiency in human cells harboring 4977bp deletion of mitochondrial DNA. Biochim Biophys Acta Mol Basis Dis 2013; 1832:216-27. [DOI: 10.1016/j.bbadis.2012.10.002] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2012] [Revised: 09/22/2012] [Accepted: 10/01/2012] [Indexed: 11/22/2022]
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379
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Kim H, Ha T. Single-molecule nanometry for biological physics. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2013; 76:016601. [PMID: 23249673 PMCID: PMC3549428 DOI: 10.1088/0034-4885/76/1/016601] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Precision measurement is a hallmark of physics but the small length scale (∼nanometer) of elementary biological components and thermal fluctuations surrounding them challenge our ability to visualize their action. Here, we highlight the recent developments in single-molecule nanometry where the position of a single fluorescent molecule can be determined with nanometer precision, reaching the limit imposed by the shot noise, and the relative motion between two molecules can be determined with ∼0.3 nm precision at ∼1 ms time resolution, as well as how these new tools are providing fundamental insights into how motor proteins move on cellular highways. We will also discuss how interactions between three and four fluorescent molecules can be used to measure three and six coordinates, respectively, allowing us to correlate the movements of multiple components. Finally, we will discuss recent progress in combining angstrom-precision optical tweezers with single-molecule fluorescent detection, opening new windows for multi-dimensional single-molecule nanometry for biological physics.
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Affiliation(s)
- Hajin Kim
- Howard Hughes Medical Institute, Urbana, IL 61801, USA
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380
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Abstract
Mitochondrial oxidative phosphorylation (OXPHOS) sustains organelle function and plays a central role in cellular energy metabolism. The OXPHOS system consists of 5 multisubunit complexes (CI-CV) that are built up of 92 different structural proteins encoded by the nuclear (nDNA) and mitochondrial DNA (mtDNA). Biogenesis of a functional OXPHOS system further requires the assistance of nDNA-encoded OXPHOS assembly factors, of which 35 are currently identified. In humans, mutations in both structural and assembly genes and in genes involved in mtDNA maintenance, replication, transcription, and translation induce 'primary' OXPHOS disorders that are associated with neurodegenerative diseases including Leigh syndrome (LS), which is probably the most classical OXPHOS disease during early childhood. Here, we present the current insights regarding function, biogenesis, regulation, and supramolecular architecture of the OXPHOS system, as well as its genetic origin. Next, we provide an inventory of OXPHOS structural and assembly genes which, when mutated, induce human neurodegenerative disorders. Finally, we discuss the consequences of mutations in OXPHOS structural and assembly genes at the single cell level and how this information has advanced our understanding of the role of OXPHOS dysfunction in neurodegeneration.
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381
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Torraco A, Verrigni D, Rizza T, Meschini MC, Vazquez-Memije ME, Martinelli D, Bianchi M, Piemonte F, Dionisi-Vici C, Santorelli FM, Bertini E, Carrozzo R. TMEM70: a mutational hot spot in nuclear ATP synthase deficiency with a pivotal role in complex V biogenesis. Neurogenetics 2012; 13:375-86. [DOI: 10.1007/s10048-012-0343-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Accepted: 09/03/2012] [Indexed: 02/01/2023]
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382
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Spinazzi M, Casarin A, Pertegato V, Salviati L, Angelini C. Assessment of mitochondrial respiratory chain enzymatic activities on tissues and cultured cells. Nat Protoc 2012; 7:1235-46. [PMID: 22653162 DOI: 10.1038/nprot.2012.058] [Citation(s) in RCA: 673] [Impact Index Per Article: 56.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The assessment of mitochondrial respiratory chain (RC) enzymatic activities is essential for investigating mitochondrial function in several situations, including mitochondrial disorders, diabetes, cancer, aging and neurodegeneration, as well as for many toxicological assays. Muscle is the most commonly analyzed tissue because of its high metabolic rates and accessibility, although other tissues and cultured cell lines can be used. We describe a step-by-step protocol for a simple and reliable assessment of the RC enzymatic function (complexes I-IV) for minute quantities of muscle, cultured cells and isolated mitochondria from a variety of species and tissues, by using a single-wavelength spectrophotometer. An efficient tissue disruption and the choice for each assay of specific buffers, substrates, adjuvants and detergents in a narrow concentration range allow maximal sensitivity, specificity and linearity of the kinetics. This protocol can be completed in 3 h.
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Affiliation(s)
- Marco Spinazzi
- Neuromuscular Laboratory, Department of Neurosciences, University of Padova, Padova, Italy.
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383
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Spinazzi M, Casarin A, Pertegato V, Salviati L, Angelini C. Assessment of mitochondrial respiratory chain enzymatic activities on tissues and cultured cells. Nat Protoc 2012. [DOI: 10.1038/nprot.2012.058 nprot] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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