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Chertkova RV, Firsov AM, Brazhe NA, Nikelshparg EI, Bochkova ZV, Bryantseva TV, Semenova MA, Baizhumanov AA, Kotova EA, Kirpichnikov MP, Maksimov GV, Antonenko YN, Dolgikh DA. Multiple Mutations in the Non-Ordered Red Ω-Loop Enhance the Membrane-Permeabilizing and Peroxidase-like Activity of Cytochrome c. Biomolecules 2022; 12:biom12050665. [PMID: 35625593 PMCID: PMC9138828 DOI: 10.3390/biom12050665] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2022] [Revised: 04/27/2022] [Accepted: 04/30/2022] [Indexed: 02/04/2023] Open
Abstract
A key event in the cytochrome c-dependent apoptotic pathway is the permeabilization of the outer mitochondrial membrane, resulting in the release of various apoptogenic factors, including cytochrome c, into the cytosol. It is believed that the permeabilization of the outer mitochondrial membrane can be induced by the peroxidase activity of cytochrome c in a complex with cardiolipin. Using a number of mutant variants of cytochrome c, we showed that both substitutions of Lys residues from the universal binding site for oppositely charged Glu residues and mutations leading to a decrease in the conformational mobility of the red Ω-loop in almost all cases did not affect the ability of cytochrome c to bind to cardiolipin. At the same time, the peroxidase activity of all mutant variants in a complex with cardiolipin was three to five times higher than that of the wild type. A pronounced increase in the ability to permeabilize the lipid membrane in the presence of hydrogen peroxide, as measured by calcein leakage from liposomes, was observed only in the case of four substitutions in the red Ω-loop (M4 mutant). According to resonance and surface-enhanced Raman spectroscopy, the mutations caused significant changes in the heme of oxidized cytochrome c molecules resulting in an increased probability of the plane heme conformation and the enhancement of the rigidity of the protein surrounding the heme. The binding of wild-type and mutant forms of oxidized cytochrome c to cardiolipin-containing liposomes caused the disordering of the acyl lipid chains that was more pronounced for the M4 mutant. Our findings indicate that the Ω-loop is important for the pore formation in cardiolipin-containing membranes.
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Affiliation(s)
- Rita V. Chertkova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia; (Z.V.B.); (T.V.B.); (M.A.S.); (M.P.K.); (D.A.D.)
- Correspondence: (R.V.C.); (N.A.B.)
| | - Alexander M. Firsov
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119991 Moscow, Russia; (A.M.F.); (E.A.K.); (Y.N.A.)
| | - Nadezda A. Brazhe
- Biophysics Department, Biological Faculty, Lomonosov Moscow State University, 119234 Moscow, Russia; (E.I.N.); (A.A.B.); (G.V.M.)
- Correspondence: (R.V.C.); (N.A.B.)
| | - Evelina I. Nikelshparg
- Biophysics Department, Biological Faculty, Lomonosov Moscow State University, 119234 Moscow, Russia; (E.I.N.); (A.A.B.); (G.V.M.)
| | - Zhanna V. Bochkova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia; (Z.V.B.); (T.V.B.); (M.A.S.); (M.P.K.); (D.A.D.)
- Biophysics Department, Biological Faculty, Lomonosov Moscow State University, 119234 Moscow, Russia; (E.I.N.); (A.A.B.); (G.V.M.)
| | - Tatyana V. Bryantseva
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia; (Z.V.B.); (T.V.B.); (M.A.S.); (M.P.K.); (D.A.D.)
- Biology Department, Lomonosov Moscow State University, 119899 Moscow, Russia
| | - Marina A. Semenova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia; (Z.V.B.); (T.V.B.); (M.A.S.); (M.P.K.); (D.A.D.)
| | - Adil A. Baizhumanov
- Biophysics Department, Biological Faculty, Lomonosov Moscow State University, 119234 Moscow, Russia; (E.I.N.); (A.A.B.); (G.V.M.)
| | - Elena A. Kotova
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119991 Moscow, Russia; (A.M.F.); (E.A.K.); (Y.N.A.)
| | - Mikhail P. Kirpichnikov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia; (Z.V.B.); (T.V.B.); (M.A.S.); (M.P.K.); (D.A.D.)
- Biology Department, Lomonosov Moscow State University, 119899 Moscow, Russia
| | - Georgy V. Maksimov
- Biophysics Department, Biological Faculty, Lomonosov Moscow State University, 119234 Moscow, Russia; (E.I.N.); (A.A.B.); (G.V.M.)
- Federal State Autonomous Educational Institution of Higher Education “National Research Technological University “MISiS””, 119049 Moscow, Russia
| | - Yuriy N. Antonenko
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119991 Moscow, Russia; (A.M.F.); (E.A.K.); (Y.N.A.)
| | - Dmitry A. Dolgikh
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia; (Z.V.B.); (T.V.B.); (M.A.S.); (M.P.K.); (D.A.D.)
- Biology Department, Lomonosov Moscow State University, 119899 Moscow, Russia
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Khoroshyy P, Tenger K, Chertkova RV, Bocharova OV, Kirpichnikov MP, Borovok N, Groma GI, Dolgikh DA, Kotlyar AB, Zimányi L. Kinetics and Energetics of Intramolecular Electron Transfer in Single-Point Labeled TUPS-Cytochrome c Derivatives. Molecules 2021; 26:molecules26226976. [PMID: 34834068 PMCID: PMC8621336 DOI: 10.3390/molecules26226976] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 11/13/2021] [Accepted: 11/16/2021] [Indexed: 11/16/2022] Open
Abstract
Electron transfer within and between proteins is a fundamental biological phenomenon, in which efficiency depends on several physical parameters. We have engineered a number of horse heart cytochrome c single-point mutants with cysteine substitutions at various positions of the protein surface. To these cysteines, as well as to several native lysine side chains, the photoinduced redox label 8-thiouredopyrene-1,3,6-trisulfonate (TUPS) was covalently attached. The long-lived, low potential triplet excited state of TUPS, generated with high quantum efficiency, serves as an electron donor to the oxidized heme c. The rates of the forward (from the label to the heme) and the reverse (from the reduced heme back to the oxidized label) electron transfer reactions were obtained from multichannel and single wavelength flash photolysis absorption kinetic experiments. The electronic coupling term and the reorganization energy for electron transfer in this system were estimated from temperature-dependent experiments and compared with calculated parameters using the crystal and the solution NMR structure of the protein. These results together with the observation of multiexponential kinetics strongly support earlier conclusions that the flexible arm connecting TUPS to the protein allows several shortcut routes for the electron involving through space jumps between the label and the protein surface.
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Affiliation(s)
- Petro Khoroshyy
- Institute of Biophysics, Biological Research Centre, Temesvári Körút 62, H-6726 Szeged, Hungary; (P.K.); (K.T.); (G.I.G.)
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Science, Flemingovo Náměstí 542/2, 16000 Prague, Czech Republic
| | - Katalin Tenger
- Institute of Biophysics, Biological Research Centre, Temesvári Körút 62, H-6726 Szeged, Hungary; (P.K.); (K.T.); (G.I.G.)
| | - Rita V. Chertkova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, 117997 Moscow, Russia; (R.V.C.); (O.V.B.); (M.P.K.); (D.A.D.)
| | - Olga V. Bocharova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, 117997 Moscow, Russia; (R.V.C.); (O.V.B.); (M.P.K.); (D.A.D.)
| | - Mikhail P. Kirpichnikov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, 117997 Moscow, Russia; (R.V.C.); (O.V.B.); (M.P.K.); (D.A.D.)
- Biology Department, Lomonosov Moscow State University, Leninskie Gory 1/12, 119899 Moscow, Russia
| | - Natalia Borovok
- Department of Biochemistry and Molecular Biology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Ramat Aviv, Tel Aviv 69978, Israel; (N.B.); (A.B.K.)
| | - Géza I. Groma
- Institute of Biophysics, Biological Research Centre, Temesvári Körút 62, H-6726 Szeged, Hungary; (P.K.); (K.T.); (G.I.G.)
| | - Dmitry A. Dolgikh
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, 117997 Moscow, Russia; (R.V.C.); (O.V.B.); (M.P.K.); (D.A.D.)
- Biology Department, Lomonosov Moscow State University, Leninskie Gory 1/12, 119899 Moscow, Russia
| | - Alexander B. Kotlyar
- Department of Biochemistry and Molecular Biology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Ramat Aviv, Tel Aviv 69978, Israel; (N.B.); (A.B.K.)
| | - László Zimányi
- Institute of Biophysics, Biological Research Centre, Temesvári Körút 62, H-6726 Szeged, Hungary; (P.K.); (K.T.); (G.I.G.)
- Correspondence:
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Amino Acid Substitutions in the Non-Ordered Ω-Loop 70–85 Affect Electron Transfer Function and Secondary Structure of Mitochondrial Cytochrome c. CRYSTALS 2021. [DOI: 10.3390/cryst11080973] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The secondary structure of horse cytochrome c with mutations in the P76GTKMIFA83 site of the Ω-loop, exhibiting reduced efficiency of electron transfer, were studied. CD spectroscopy studies showed that the ordering of mutant structure increases by 3–6% compared to that of the WT molecules due to the higher content of β-structural elements. The IR spectroscopy data are consistent with the CD results and demonstrate that some α-helical elements change into β-structures, and the amount of the non-structured elements is decreased. The analysis of the 1H-NMR spectra demonstrated that cytochrome c mutants have a well-determined secondary structure with some specific features related to changes in the heme microenvironment. The observed changes in the structure of cytochrome c mutants are likely to be responsible for the decrease in the conformational mobility of the P76GTKMIFA83 sequence carrying mutations and for the decline in succinate:cytochrome c-reductase and cytochrome c-oxidase activities in the mitoplast system in the presence of these cytochromes c. We suggest that the decreased efficiency of the electron transfer of the studied cytochromes c may arise due to: (1) the change in the protein conformation in sites responsible for the interaction of cytochrome c with complexes III and IV and (2) the change in the heme conformation that deteriorates its optimal orientation towards donor and acceptor in complexes III and IV therefore slows down electron transfer. The results obtained are consistent with the previously proposed model of mitochondrial cytochrome c functioning associated with the deterministic mobility of protein globule parts.
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Lysine 72 substitutions differently affect lipid membrane permeabilizing and proapoptotic activities of horse heart cytochrome c. Biochem Biophys Res Commun 2021; 548:74-77. [PMID: 33631678 DOI: 10.1016/j.bbrc.2021.02.023] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Accepted: 02/05/2021] [Indexed: 12/25/2022]
Abstract
Peroxidase activity of cytochrome c (cyt c)/cardiolipin (CL) complex is supposed to be involved in the initiation of apoptosis via peroxidative induction of mitochondrial membrane permeabilization. As cyt c binding to CL-containing membranes is at least partially associated with electrostatic protein/lipid interaction, we screened single-point mutants of horse heart cyt c with various substitutions of lysine at position 72, considered to play a significant role in both the binding and peroxidase activity of the protein. Contrary to expectations, K72A, K72R and K72L substitutions exerted slight effects on both the cyt c binding to CL-containing liposomal membranes and the cyt c/H2O2-induced calcein leakage from liposomes, used here as a membrane permeabilization assay. Both the binding and permeabilization were decreased to various extents, but not significantly, in the case of K72E and K72N mutants. A drastic difference was found between the sequence of the permeabilizing activities of the cyt c variants and the previously described order of their proapoptotic activities (Chertkova et al., 2008).
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Chertkova RV, Brazhe NA, Bryantseva TV, Nekrasov AN, Dolgikh DA, Yusipovich AI, Sosnovtseva O, Maksimov GV, Rubin AB, Kirpichnikov MP. New insight into the mechanism of mitochondrial cytochrome c function. PLoS One 2017; 12:e0178280. [PMID: 28562658 PMCID: PMC5451065 DOI: 10.1371/journal.pone.0178280] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Accepted: 05/10/2017] [Indexed: 11/22/2022] Open
Abstract
We investigate functional role of the P76GTKMIFA83 fragment of the primary structure of cytochrome c. Based on the data obtained by the analysis of informational structure (ANIS), we propose a model of functioning of cytochrome c. According to this model, conformational rearrangements of the P76GTKMIFA83 loop fragment have a significant effect on conformational mobility of the heme. It is suggested that the conformational mobility of cytochrome c heme is responsible for its optimal orientation with respect to electron donor and acceptor within ubiquinol–cytochrome c oxidoreductase (complex III) and cytochrome c oxidase (complex IV), respectively, thus, ensuring electron transfer from complex III to complex IV. To validate the model, we design several mutant variants of horse cytochrome c with multiple substitutions of amino acid residues in the P76GTKMIFA83 sequence that reduce its ability to undergo conformational rearrangements. With this, we study the succinate–cytochrome c reductase and cytochrome c oxidase activities of rat liver mitoplasts in the presence of mutant variants of cytochrome c. The electron transport activity of the mutant variants decreases to different extent. Resonance Raman spectroscopy (RRS) and surface-enhanced Raman spectroscopy (SERS) data demonstrate, that all mutant cytochromes possess heme with the higher degree of ruffling deformation, than that of the wild-type (WT) cytochrome c. The increase in the ruffled deformation of the heme of oxidized cytochromes correlated with the decrease in the electron transport rate of ubiquinol–cytochrome c reductase (complex III). Besides, all mutant cytochromes have lower mobility of the pyrrol rings and methine bridges, than WT cytochrome c. We show that a decrease in electron transport activity in the mutant variants correlates with conformational changes and reduced mobility of heme porphyrin. This points to a significant role of the P76GTKMIFA83 fragment in the electron transport function of cytochrome c.
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Affiliation(s)
- Rita V. Chertkova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, The Russian Academy of Sciences, Moscow, Russia
- * E-mail: (RVC); (NAB)
| | - Nadezda A. Brazhe
- Biophysics Department, Biological faculty, M.V. Lomonosov Moscow State University, Moscow, Russia
- * E-mail: (RVC); (NAB)
| | - Tatiana V. Bryantseva
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, The Russian Academy of Sciences, Moscow, Russia
- Biophysics Department, Biological faculty, M.V. Lomonosov Moscow State University, Moscow, Russia
| | - Alexey N. Nekrasov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, The Russian Academy of Sciences, Moscow, Russia
| | - Dmitry A. Dolgikh
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, The Russian Academy of Sciences, Moscow, Russia
- Biophysics Department, Biological faculty, M.V. Lomonosov Moscow State University, Moscow, Russia
| | - Alexander I. Yusipovich
- Biophysics Department, Biological faculty, M.V. Lomonosov Moscow State University, Moscow, Russia
| | - Olga Sosnovtseva
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, Copenhagen University, Copenhagen, Denmark
| | - Georgy V. Maksimov
- Biophysics Department, Biological faculty, M.V. Lomonosov Moscow State University, Moscow, Russia
| | - Andrei B. Rubin
- Biophysics Department, Biological faculty, M.V. Lomonosov Moscow State University, Moscow, Russia
| | - Mikhail P. Kirpichnikov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, The Russian Academy of Sciences, Moscow, Russia
- Biophysics Department, Biological faculty, M.V. Lomonosov Moscow State University, Moscow, Russia
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Vinogradov AD, Grivennikova VG. Oxidation of NADH and ROS production by respiratory complex I. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2015; 1857:863-71. [PMID: 26571336 DOI: 10.1016/j.bbabio.2015.11.004] [Citation(s) in RCA: 96] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Revised: 11/02/2015] [Accepted: 11/07/2015] [Indexed: 12/14/2022]
Abstract
Kinetic characteristics of the proton-pumping NADH:quinone reductases (respiratory complexes I) are reviewed. Unsolved problems of the redox-linked proton translocation activities are outlined. The parameters of complex I-mediated superoxide/hydrogen peroxide generation are summarized, and the physiological significance of mitochondrial ROS production is discussed. This article is part of a Special Issue entitled Respiratory complex I, edited by Volker Zickermann and Ulrich Brandt.
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Affiliation(s)
- Andrei D Vinogradov
- Department of Biochemistry, School of Biology, Moscow State University, Moscow 119991.
| | - Vera G Grivennikova
- Department of Biochemistry, School of Biology, Moscow State University, Moscow 119991
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Abstract
SIGNIFICANCE The molecular mechanism of aging is still vigorously debated, although a general consensus exists that mitochondria are significantly involved in this process. However, the previously postulated role of mitochondrial-derived reactive oxygen species (ROS) as the damaging agents inducing functional loss in aging has fallen out of favor in the recent past. In this review, we critically examine the role of ROS in aging in the light of recent advances on the relationship between mitochondrial structure and function. RECENT ADVANCES The functional mitochondrial respiratory chain is now recognized as a reflection of the dynamic association of respiratory complexes in the form of supercomplexes (SCs). Besides providing kinetic advantage (channeling), SCs control ROS generation by the respiratory chain, thus providing a means to regulate ROS levels in the cell. Depending on their concentration, these ROS are either physiological signals essential for the life of the cell or toxic species that damage cell structure and functions. CRITICAL ISSUES We propose that under physiological conditions the dynamic nature of SCs reversibly controls the generation of ROS as signals involved in mitochondrial-nuclear communication. During aging, there is a progressive loss of control of ROS generation so that their production is irreversibly enhanced, inducing a vicious circle in which signaling is altered and structural damage takes place. FUTURE DIRECTIONS A better understanding on the forces affecting SC association would allow the manipulation of ROS generation, directing these species to their physiological signaling role.
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Affiliation(s)
- Maria Luisa Genova
- Dipartimento di Scienze Biomediche e Neuromotorie, Alma Mater Studiorum-Università di Bologna , Bologna, Italy
| | - Giorgio Lenaz
- Dipartimento di Scienze Biomediche e Neuromotorie, Alma Mater Studiorum-Università di Bologna , Bologna, Italy
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Grivennikova VG, Vinogradov AD. Mitochondrial production of reactive oxygen species. BIOCHEMISTRY (MOSCOW) 2014; 78:1490-511. [PMID: 24490736 DOI: 10.1134/s0006297913130087] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Numerous biochemical studies are aimed at elucidating the sources and mechanisms of formation of reactive oxygen species (ROS) because they are involved in cellular, organ-, and tissue-specific physiology. Mitochondria along with other cellular organelles of eukaryotes contribute significantly to ROS formation and utilization. This review is a critical account of the mitochondrial ROS production and methods for their registration. The physiological and pathophysiological significance of the mitochondrially produced ROS are discussed.
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Affiliation(s)
- V G Grivennikova
- Department of Biochemistry, Biological Faculty, Lomonosov Moscow State University, Moscow, 119991, Russia.
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Abstract
FUS1/TUSC2 is a mitochondrial tumor suppressor with activity to regulate cellular oxidative stress by maintaining balanced ROS production and mitochondrial homeostasis. Fus1 expression is inhibited by ROS, suggesting that individuals with a high level of ROS may have lower Fus1 in normal tissues and, thus, may be more prone to oxidative stress-induced side effects of cancer treatment, including radiotherapy. As the role of Fus1 in the modulation of cellular radiosensitivity is unknown, we set out to determine molecular mechanisms of Fus1 involvement in the IR response in normal tissues. Mouse whole-body irradiation methodology was employed to determine the role for Fus1 in the radiation response and explore underlying molecular mechanisms. Fus1(-/-) mice were more susceptible to radiation compared with Fus1(+/+) mice, exhibiting increased mortality and accelerated apoptosis of the GI crypt epithelial cells. Following untimely reentrance into the cell cycle, the Fus1(-/-) GI crypt cells died at accelerated rate via mitotic catastrophe that resulted in diminished and/or delayed crypt regeneration after irradiation. At the molecular level, dysregulated dynamics of activation of main IR response proteins (p53, NFκB, and GSK-3β), as well as key signaling pathways involved in oxidative stress response (SOD2, PRDX1, and cytochrome c), apoptosis (BAX and PARP1), cell cycle (Cyclins B1 and D1), and DNA repair (γH2AX) were found in Fus1(-/-) cells after irradiation. Increased radiosensitivity of other tissues, such as immune cells and hair follicles was also detected in Fus1(-/-) mice. Our findings demonstrate a previously unknown radioprotective function of the mitochondrial tumor suppressor Fus1 in normal tissues and suggest new individualized therapeutic approaches based on Fus1 expression.
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Mitochondrial hydrogen peroxide production as determined by the pyridine nucleotide pool and its redox state. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2012; 1817:1879-85. [PMID: 22503830 DOI: 10.1016/j.bbabio.2012.03.033] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2012] [Revised: 03/27/2012] [Accepted: 03/29/2012] [Indexed: 11/21/2022]
Abstract
The rates of NADH-supported superoxide/hydrogen peroxide production by membrane-bound bovine heart respiratory complex I, soluble pig heart dihydrolipoamide dehydrogenase (DLDH), and by accompanying operation of these enzymes in rat heart mitochondrial matrix were measured as a function of the pool of pyridine nucleotides and its redox state. Each of the activities showed nontrivial dependence on nucleotide pool concentration. The NAD(+)/NADH ratios required for their half maximal capacities were determined. About half of the total NADH-supported H(2)O(2) production by permeabilized mitochondria in the absence of stimulating ammonium could be accounted for by DLDH activity. The significance of the mitochondrial NADH-dependent hydrogen peroxide production under physiologically relevant conditions is discussed. This article is part of a Special Issue entitled: 17th European Bioenergetics Conference (EBEC 2012).
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The mitochondrial cytochrome c
N-terminal region is critical for maturation by holocytochrome c
synthase. FEBS Lett 2011; 585:1891-6. [DOI: 10.1016/j.febslet.2011.04.058] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2011] [Revised: 04/18/2011] [Accepted: 04/20/2011] [Indexed: 11/19/2022]
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