|
1
|
Ren X, Léveillard T. Modulating antioxidant systems as a therapeutic approach to retinal degeneration. Redox Biol 2022; 57:102510. [PMID: 36274523 PMCID: PMC9596747 DOI: 10.1016/j.redox.2022.102510] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 10/11/2022] [Accepted: 10/11/2022] [Indexed: 11/21/2022] Open
Abstract
The human retina is facing a big challenge of reactive oxygen species (ROS) from endogenous and exogenous sources. Excessive ROS can cause damage to DNA, lipids, and proteins, triggering abnormal redox signaling, and ultimately lead to cell death. Thus, oxidative stress has been observed in inherited retinal diseases as a common hallmark. To counteract the detrimental effect of ROS, cells are equipped with various antioxidant defenses. In this review, we will focus on the antioxidant systems in the retina and how they can protect retina from oxidative stress. Both small antioxidants and antioxidant enzymes play a role in ROS removal. Particularly, the thioredoxin and glutaredoxin systems, as the major antioxidant systems in mammalian cells, exert functions in redox signaling regulation via modifying cysteines in proteins. In addition, the thioredoxin-like rod-derived cone viability factor (RdCVFL) and thioredoxin interacting protein (TXNIP) can modulate metabolism in photoreceptors and promote their survival. In conclusion, elevating the antioxidant capacity in retina is a promising therapy to curb the progress of inherited retinal degeneration.
Collapse
Affiliation(s)
- Xiaoyuan Ren
- Department of Genetics, Sorbonne Université, INSERM, CNRS, Institut de la Vision, 17 rue Moreau, F-75012 Paris, France; Division of Biochemistry, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, 17177, Sweden.
| | - Thierry Léveillard
- Department of Genetics, Sorbonne Université, INSERM, CNRS, Institut de la Vision, 17 rue Moreau, F-75012 Paris, France.
| |
Collapse
|
|
2
|
The Function of Selenium in Central Nervous System: Lessons from MsrB1 Knockout Mouse Models. Molecules 2021; 26:molecules26051372. [PMID: 33806413 PMCID: PMC7961861 DOI: 10.3390/molecules26051372] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 02/25/2021] [Accepted: 02/25/2021] [Indexed: 11/17/2022] Open
Abstract
MsrB1 used to be named selenoprotein R, for it was first identified as a selenocysteine containing protein by searching for the selenocysteine insert sequence (SECIS) in the human genome. Later, it was found that MsrB1 is homologous to PilB in Neisseria gonorrhoeae, which is a methionine sulfoxide reductase (Msr), specifically reducing L-methionine sulfoxide (L-Met-O) in proteins. In humans and mice, four members constitute the Msr family, which are MsrA, MsrB1, MsrB2, and MsrB3. MsrA can reduce free or protein-containing L-Met-O (S), whereas MsrBs can only function on the L-Met-O (R) epimer in proteins. Though there are isomerases existent that could transfer L-Met-O (S) to L-Met-O (R) and vice-versa, the loss of Msr individually results in different phenotypes in mice models. These observations indicate that the function of one Msr cannot be totally complemented by another. Among the mammalian Msrs, MsrB1 is the only selenocysteine-containing protein, and we recently found that loss of MsrB1 perturbs the synaptic plasticity in mice, along with the astrogliosis in their brains. In this review, we summarized the effects resulting from Msr deficiency and the bioactivity of selenium in the central nervous system, especially those that we learned from the MsrB1 knockout mouse model. We hope it will be helpful in better understanding how the trace element selenium participates in the reduction of L-Met-O and becomes involved in neurobiology.
Collapse
|
|
3
|
Zhao L. Mitochondrial DNA degradation: A quality control measure for mitochondrial genome maintenance and stress response. Enzymes 2019; 45:311-341. [PMID: 31627882 DOI: 10.1016/bs.enz.2019.08.004] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Mitochondria play a central role in bioenergetics, and fulfill a plethora of functions in cell signaling, programmed cell death, and biosynthesis of key protein cofactors. Mitochondria harbor their own genomic DNA, which encodes protein subunits of the electron transport chain and a full set of transfer and ribosomal RNAs. Mitochondrial DNA (mtDNA) is essential for cellular and organismal functions, and defects in mitochondrial genome maintenance have been implicated in common human diseases and mitochondrial disorders. mtDNA repair and degradation are known pathways to cope with mtDNA damage; however, molecular factors involved in this process have remained unclear. Such knowledge is fundamental to the understanding of mitochondrial genomic maintenance and pathology, because mtDNA degradation may contribute to the etiology of mtDNA depletion syndromes and to the activation of the innate immune response by fragmented mtDNA. This article reviews the current literature regarding the importance of mitochondrial DNA degradation in mtDNA maintenance and stress response, and the recent progress in uncovering molecular factors involved in mtDNA degradation. These factors include key components of the mtDNA replication machinery, such as DNA polymerase γ, helicase Twinkle, and exonuclease MGME1, as well as a major DNA-packaging protein, mitochondrial transcription factor A (TFAM).
Collapse
Affiliation(s)
- Linlin Zhao
- Department of Chemistry, University of California, Riverside, Riverside, CA, United States.
| |
Collapse
|
|
4
|
Achilli C, Ciana A, Minetti G. The discovery of methionine sulfoxide reductase enzymes: An historical account and future perspectives. Biofactors 2015; 41:135-52. [PMID: 25963551 DOI: 10.1002/biof.1214] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Accepted: 04/19/2015] [Indexed: 01/26/2023]
Abstract
L-Methionine (L-Met) is the only sulphur-containing proteinogenic amino acid together with cysteine. Its importance is highlighted by it being the initiator amino acid for protein synthesis in all known living organisms. L-Met, free or inserted into proteins, is sensitive to oxidation of its sulfide moiety, with formation of L-Met sulfoxide. The sulfoxide could not be inserted into proteins, and the oxidation of L-Met in proteins often leads to the loss of biological activity of the affected molecule. Key discoveries revealed the existence, in rats, of a metabolic pathway for the reduction of free L-Met sulfoxide and, later, in Escherichia coli, of the enzymatic reduction of L-Met sulfoxide inserted in proteins. Upon oxidation, the sulphur atom becomes a new stereogenic center, and two stable diastereoisomers of L-Met sulfoxide exist. A fundamental discovery revealed the existence of two unrelated families of enzymes, MsrA and MsrB, whose members display opposite stereospecificity of reduction for the two sulfoxides. The importance of Msrs is additionally emphasized by the discovery that one of the only 25 selenoproteins expressed in humans is a Msr. The milestones on the road that led to the discovery and characterization of this group of antioxidant enzymes are recounted in this review.
Collapse
Affiliation(s)
- Cesare Achilli
- Laboratories of Biochemistry, Department of Biology and Biotechnology, University of Pavia, Pavia, Italy
| | - Annarita Ciana
- Laboratories of Biochemistry, Department of Biology and Biotechnology, University of Pavia, Pavia, Italy
| | - Giampaolo Minetti
- Laboratories of Biochemistry, Department of Biology and Biotechnology, University of Pavia, Pavia, Italy
| |
Collapse
|
|
5
|
Kim HY. The methionine sulfoxide reduction system: selenium utilization and methionine sulfoxide reductase enzymes and their functions. Antioxid Redox Signal 2013; 19. [PMID: 23198996 PMCID: PMC3763222 DOI: 10.1089/ars.2012.5081] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
SIGNIFICANCE Selenium is utilized in the methionine sulfoxide reduction system that occurs in most organisms. Methionine sulfoxide reductases (Msrs), MsrA and MsrB, are the enzymes responsible for this system. Msrs repair oxidatively damaged proteins, protect against oxidative stress, and regulate protein function, and have also been implicated in the aging process. Selenoprotein forms of Msrs containing selenocysteine (Sec) at the catalytic site are found in bacteria, algae, and animals. RECENT ADVANCES A selenoprotein MsrB1 knockout mouse has been developed. Significant progress in the biochemistry of Msrs has been made, which includes findings of a novel reducing system for Msrs and of an interesting reason for the use of Sec in the Msr system. The effects of mammalian MsrBs, including selenoprotein MsrB1 on fruit fly aging, have been investigated. Furthermore, it is evident that Msrs are involved in methionine metabolism and regulation of the trans-sulfuration pathway. CRITICAL ISSUES This article presents recent progress in the Msr field while focusing on the physiological roles of mammalian Msrs, functions of selenoprotein forms of Msrs, and their biochemistry. FUTURE DIRECTIONS A deeper understanding of the roles of Msrs in redox signaling, the aging process, and metabolism will be achieved. The identity of selenoproteome of Msrs will be sought along with characterization of the identified selenoprotein forms. Exploring new cellular targets and new functions of Msrs is also warranted.
Collapse
Affiliation(s)
- Hwa-Young Kim
- Department of Biochemistry and Molecular Biology, Yeungnam University College of Medicine, Daegu, Republic of Korea.
| |
Collapse
|
|
6
|
Hansel A, Jung S, Hoshi T, Heinemann SH. A second human methionine sulfoxide reductase (hMSRB2) reducing methionine-R-sulfoxide displays a tissue expression pattern distinct from hMSRB1. Redox Rep 2013; 8:384-8. [PMID: 14980072 DOI: 10.1179/135100003225003429] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Peptide methionine sulfoxide reductases are important enzymes in the defense against cellular oxidative stress as they reduce methionine sulfoxide, the product of methionine oxidation by physiologically relevant reactive oxygen species. Two distinct enzyme classes, MSRA and MSRB, have evolved for selectively reducing the two epimers, methionine-S-sulfoxide and methionine-R-sulfoxide. A new human MSR enzyme (hMSRB2) specifically reducing methionine-R-sulfoxide, which showed a conversion rate for peptide-bound methionine-S-sulfoxide similar to hMSRB1, was characterized with respect to its tissue expression. As previously found for hMSRB1, expression of hMSRB2 mRNA was weak in brain, but strong in heart and skeletal muscle. In contrast to hMSRB1, its expression was high in smooth muscle-containing organs (digestive system, bladder), lung and aorta, while hMSRB1 displayed a higher expression than hMSRB2 in liver and kidney.
Collapse
Affiliation(s)
- Alfred Hansel
- Molecular and Cellular Biophysics, Medical Faculty of the Friedrich Schiller University Jena, Jena, Germany
| | | | | | | |
Collapse
|
|
7
|
Lee S, Kim SM, Lee RT. Thioredoxin and thioredoxin target proteins: from molecular mechanisms to functional significance. Antioxid Redox Signal 2013; 18:1165-207. [PMID: 22607099 PMCID: PMC3579385 DOI: 10.1089/ars.2011.4322] [Citation(s) in RCA: 312] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The thioredoxin (Trx) system is one of the central antioxidant systems in mammalian cells, maintaining a reducing environment by catalyzing electron flux from nicotinamide adenine dinucleotide phosphate through Trx reductase to Trx, which reduces its target proteins using highly conserved thiol groups. While the importance of protecting cells from the detrimental effects of reactive oxygen species is clear, decades of research in this field revealed that there is a network of redox-sensitive proteins forming redox-dependent signaling pathways that are crucial for fundamental cellular processes, including metabolism, proliferation, differentiation, migration, and apoptosis. Trx participates in signaling pathways interacting with different proteins to control their dynamic regulation of structure and function. In this review, we focus on Trx target proteins that are involved in redox-dependent signaling pathways. Specifically, Trx-dependent reductive enzymes that participate in classical redox reactions and redox-sensitive signaling molecules are discussed in greater detail. The latter are extensively discussed, as ongoing research unveils more and more details about the complex signaling networks of Trx-sensitive signaling molecules such as apoptosis signal-regulating kinase 1, Trx interacting protein, and phosphatase and tensin homolog, thus highlighting the potential direct and indirect impact of their redox-dependent interaction with Trx. Overall, the findings that are described here illustrate the importance and complexity of Trx-dependent, redox-sensitive signaling in the cell. Our increasing understanding of the components and mechanisms of these signaling pathways could lead to the identification of new potential targets for the treatment of diseases, including cancer and diabetes.
Collapse
Affiliation(s)
- Samuel Lee
- The Harvard Stem Cell Institute, Cambridge, MA, USA
| | | | | |
Collapse
|
|
8
|
Structural insights into interaction between mammalian methionine sulfoxide reductase B1 and thioredoxin. J Biomed Biotechnol 2012; 2012:586539. [PMID: 22505815 PMCID: PMC3312296 DOI: 10.1155/2012/586539] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2011] [Revised: 11/19/2011] [Accepted: 11/24/2011] [Indexed: 01/12/2023] Open
Abstract
Maintenance of the cellular redox balance has vital importance for correcting organism functioning. Methionine sulfoxide reductases (Msrs) are among the key members of the cellular antioxidant defence system. To work properly, methionine sulfoxide reductases need to be reduced by their biological partner, thioredoxin (Trx). This process, according to the available kinetic data, represents the slowest step in the Msrs catalytic cycle. In the present paper, we investigated structural aspects of the intermolecular complex formation between mammalian MsrB1 and Trx. NMR spectroscopy and biocomputing were the two mostly used through the research approaches. The formation of NMR detectable MsrB1/Trx complex was monitored and studied in attempt to understand MsrB1 reduction mechanism. Using NMR data, molecular mechanics, protein docking, and molecular dynamics simulations, it was found that intermediate MsrB1/Trx complex is stabilized by interprotein β-layer. The complex formation accompanied by distortion of disulfide bond within MsrB1 facilitates the reduction of oxidized MsrB1 as it is evidenced by the obtained data.
Collapse
|
|
9
|
Sreekumar PG, Hinton DR, Kannan R. Methionine sulfoxide reductase A: Structure, function and role in ocular pathology. World J Biol Chem 2011; 2:184-92. [PMID: 21909460 PMCID: PMC3163237 DOI: 10.4331/wjbc.v2.i8.184] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/17/2011] [Revised: 07/27/2011] [Accepted: 08/03/2011] [Indexed: 02/05/2023] Open
Abstract
Methionine is a highly susceptible amino acid that can be oxidized to S and R diastereomeric forms of methionine sulfoxide by many of the reactive oxygen species generated in biological systems. Methionine sulfoxide reductases (Msrs) are thioredoxin-linked enzymes involved in the enzymatic conversion of methionine sulfoxide to methionine. Although MsrA and MsrB have the same function of methionine reduction, they differ in substrate specificity, active site composition, subcellular localization, and evolution. MsrA has been localized in different ocular regions and is abundantly expressed in the retina and in retinal pigment epithelial (RPE) cells. MsrA protects cells from oxidative stress. Overexpression of MsrA increases resistance to cell death, while silencing or knocking down MsrA decreases cell survival; events that are mediated by mitochondria. MsrA participates in protein-protein interaction with several other cellular proteins. The interaction of MsrA with α-crystallins is of utmost importance given the known functions of the latter in protein folding, neuroprotection, and cell survival. Oxidation of methionine residues in α-crystallins results in loss of chaperone function and possibly its antiapoptotic properties. Recent work from our laboratory has shown that MsrA is co-localized with αA and αB crystallins in the retinal samples of patients with age-related macular degeneration. We have also found that chemically induced hypoxia regulates the expression of MsrA and MsrB2 in human RPE cells. Thus, MsrA is a critical enzyme that participates in cell and tissue protection, and its interaction with other proteins/growth factors may provide a target for therapeutic strategies to prevent degenerative diseases.
Collapse
Affiliation(s)
- Parameswaran G Sreekumar
- Parameswaran G Sreekumar, David R Hinton, Ram Kannan, Arnold and Mabel Beckman Macular Research Center, Doheny Eye Institute, Los Angeles, CA 90033, United States
| | | | | |
Collapse
|
|
10
|
Kaya A, Koc A, Lee BC, Fomenko DE, Rederstorff M, Krol A, Lescure A, Gladyshev VN. Compartmentalization and regulation of mitochondrial function by methionine sulfoxide reductases in yeast. Biochemistry 2010; 49:8618-25. [PMID: 20799725 PMCID: PMC3061818 DOI: 10.1021/bi100908v] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Elevated levels of reactive oxygen species can damage proteins. Sulfur-containing amino acid residues, cysteine and methionine, are particularly susceptible to such damage. Various enzymes evolved to protect proteins or repair oxidized residues, including methionine sulfoxide reductases MsrA and MsrB, which reduce methionine (S)-sulfoxide (Met-SO) and methionine (R)-sulfoxide (Met-RO) residues, respectively, back to methionine. Here, we show that MsrA and MsrB are involved in the regulation of mitochondrial function. Saccharomyces cerevisiae mutant cells lacking MsrA, MsrB, or both proteins had normal levels of mitochondria but lower levels of cytochrome c and fewer respiration-competent mitochondria. The growth of single MsrA or MsrB mutants on respiratory carbon sources was inhibited, and that of the double mutant was severely compromised, indicating impairment of mitochondrial function. Although MsrA and MsrB are thought to have similar roles in oxidative protein repair each targeting a diastereomer of methionine sulfoxide, their deletion resulted in different phenotypes. GFP fusions of MsrA and MsrB showed different localization patterns and primarily localized to cytoplasm and mitochondria, respectively. This finding agreed with compartment-specific enrichment of MsrA and MsrB activities. These results show that oxidative stress contributes to mitochondrial dysfunction through oxidation of methionine residues in proteins located in different cellular compartments.
Collapse
Affiliation(s)
- Alaattin Kaya
- Department of Biochemistry and Redox Biology Center, University of Nebraska-Lincoln, Lincoln, NE 68588, USA
| | - Ahmet Koc
- Department of Biochemistry and Redox Biology Center, University of Nebraska-Lincoln, Lincoln, NE 68588, USA
- Izmir Institute of Technology, Department of Molecular Biology and Genetics, 35430, Urla, Izmir, Turkey
| | - Byung Cheon Lee
- Department of Biochemistry and Redox Biology Center, University of Nebraska-Lincoln, Lincoln, NE 68588, USA
- Division of Genetics, Brigham and Women’s Hospital and Harvard Medical School, 77 Avenue Louis Pasteur, Boston MA 02115, USA
| | - Dmitri E. Fomenko
- Department of Biochemistry and Redox Biology Center, University of Nebraska-Lincoln, Lincoln, NE 68588, USA
| | - Mathieu Rederstorff
- Institut de Biologie Moléculaire et Cellulaire, UPR ARN du CNRS/Université Louis Pasteur, Strasbourg, France
| | - Alain Krol
- Institut de Biologie Moléculaire et Cellulaire, UPR ARN du CNRS/Université Louis Pasteur, Strasbourg, France
| | - Alain Lescure
- Institut de Biologie Moléculaire et Cellulaire, UPR ARN du CNRS/Université Louis Pasteur, Strasbourg, France
| | - Vadim N. Gladyshev
- Department of Biochemistry and Redox Biology Center, University of Nebraska-Lincoln, Lincoln, NE 68588, USA
- Division of Genetics, Brigham and Women’s Hospital and Harvard Medical School, 77 Avenue Louis Pasteur, Boston MA 02115, USA
| |
Collapse
|
|
11
|
Methionine sulfoxide reductase B2 is highly expressed in the retina and protects retinal pigmented epithelium cells from oxidative damage. Exp Eye Res 2009; 90:420-8. [PMID: 20026324 DOI: 10.1016/j.exer.2009.12.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2009] [Revised: 12/04/2009] [Accepted: 12/08/2009] [Indexed: 12/19/2022]
Abstract
Methionine sulfoxide reductase B2 (MSRB2) is a mitochondrial enzyme that converts methionine sulfoxide (R) enantiomer back to methionine. This enzyme is suspected of functioning to protect mitochondrial proteins from oxidative damage. In this study we report that the retina is one of the human tissues with highest levels of MSRB2 mRNA expression. Other tissues with high expression were heart, kidney and skeletal muscle. Overexpression of an MSRB2-GFP fusion protein increased the MSR enzymatic activity three-fold in stably transfected cultured RPE cells. This overexpression augmented the resistance of these cells to the toxicity induced by 7-ketocholesterol, tert-butyl hydroperoxide and all-trans retinoic acid. By contrast, knockdown of MSRB2 by a miRNA in stably transfected cells did not convey increased sensitivity to the oxidative stress. In the monkey retina MSRB2 localized to the ganglion cell layer (GLC), the outer plexiform layer (OPL) and the retinal pigment epithelium (RPE). MSRB2 expression is most pronounced in the OPL of the macula and foveal regions suggesting an association with the cone synaptic mitochondria. Our data suggests that MSRB2 plays an important function in protecting cones from multiple type of oxidative stress and may be critical in preserving central vision.
Collapse
|
|
12
|
Functions and evolution of selenoprotein methionine sulfoxide reductases. Biochim Biophys Acta Gen Subj 2009; 1790:1471-7. [PMID: 19406207 DOI: 10.1016/j.bbagen.2009.04.014] [Citation(s) in RCA: 132] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2009] [Revised: 04/13/2009] [Accepted: 04/22/2009] [Indexed: 11/21/2022]
Abstract
Methionine sulfoxide reductases (Msrs) are thiol-dependent enzymes which catalyze conversion of methionine sulfoxide to methionine. Three Msr families, MsrA, MsrB, and fRMsr, are known. MsrA and MsrB are responsible for the reduction of methionine-S-sulfoxide and methionine-R-sulfoxide residues in proteins, respectively, whereas fRMsr reduces free methionine-R-sulfoxide. Besides acting on proteins, MsrA can additionally reduce free methionine-S-sulfoxide. Some MsrAs and MsrBs evolved to utilize catalytic selenocysteine. This includes MsrB1, which is a major MsrB in cytosol and nucleus in mammalian cells. Specialized machinery is used for insertion of selenocysteine into MsrB1 and other selenoproteins at in-frame UGA codons. Selenocysteine offers catalytic advantage to the protein repair function of Msrs, but also makes these proteins dependent on the supply of selenium and requires adjustments in their strategies for regeneration of active enzymes. Msrs have roles in protecting cellular proteins from oxidative stress and through this function they may regulate lifespan in several model organisms.
Collapse
|
|
13
|
Haenold R, Wassef R, Hansel A, Heinemann SH, Hoshi T. Identification of a new functional splice variant of the enzyme methionine sulphoxide reductase A (MSRA) expressed in rat vascular smooth muscle cells. Free Radic Res 2008; 41:1233-45. [PMID: 17907003 DOI: 10.1080/10715760701642096] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Reactive oxygen species contribute to ageing of the vascular system and development of cardiovascular disease. Methionine-S-sulphoxide, an oxidized form of methionine, is repaired by the enzyme methionine sulphoxide reductase A (MSRA). The enzyme, targeted to mitochondria or the cytosol by alternative splicing, is vital for oxidative stress resistance. This study was designed to examine the endogenous expression and intracellular localization of MSRA in rat aortic vascular smooth muscle cells (VSMCs). We detected robust MSRA immunoreactivity exclusively in mitochondria. Sequence analysis of msrA transcripts revealed the presence of a novel mitochondrial splice variant, msrA2a, in cultured rat VSMCs as well as in aortic tissue preparations. The enzymatic activity of a recombinant MSRA2a protein was confirmed by the reduction of methionine sulphoxide in a model substrate peptide. We conclude that multiple MSRA variants participate in the repair of oxidized proteins in VSMC mitochondria, but that other protective mechanisms may exist in the cytoplasmic compartment.
Collapse
Affiliation(s)
- Ronny Haenold
- Department of Physiology, Richards D100, 3700 Hamilton Walk, University of Pennsylvania, Philadelphia, PA 19104, USA
| | | | | | | | | |
Collapse
|
|
14
|
Methionine sulfoxide reductases: selenoprotein forms and roles in antioxidant protein repair in mammals. Biochem J 2007; 407:321-9. [PMID: 17922679 DOI: 10.1042/bj20070929] [Citation(s) in RCA: 167] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Msrs (methionine sulfoxide reductases), MsrA and MsrB, are repair enzymes that reduce methionine sulfoxide residues in oxidatively damaged proteins to methionine residues in a stereospecific manner. These enzymes protect cells from oxidative stress and have been implicated in delaying the aging process and progression of neurodegenerative diseases. In recent years, significant efforts have been made to explore the catalytic properties and physiological functions of these enzymes. In the current review, we present recent progress in this area, with the focus on mammalian MsrA and MsrBs including their roles in disease, evolution and function of selenoprotein forms of MsrA and MsrB, and the biochemistry of these enzymes.
Collapse
|
|
15
|
Moskovitz J. Prolonged selenium-deficient diet in MsrA knockout mice causes enhanced oxidative modification to proteins and affects the levels of antioxidant enzymes in a tissue-specific manner. Free Radic Res 2007; 41:162-71. [PMID: 17364942 DOI: 10.1080/10715760600978823] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The methionine sulfoxide reductase (Msr) system (comprised of MsrA and MsrB) is responsible for reducing methionine sulfoxide (MetO) to methionine. One major form of MsrB is a selenoprotein. Following prolonged selenium deficient diet (SD), through F2 generation, the MsrA -/- mice exhibited higher protein-MetO and carbonyl levels relative to their wild-type (WT) control in most organs. More specifically, the SD diet caused alteration in the expression and/or activities of certain antioxidants as follows: lowering the specific activity of MsrB in the MsrA -/- cerebellum in comparison to WT mice; lowering the activities of glutathione peroxidase (Gpx) and thioredoxin reductase (Trr) especially in brains of MsrA -/- mice; elevation of the cellular levels of selenoprotein P (SelP) in most tissues of the MsrA -/- relative to WT. Unexpectedly, the expression and activity of glucose-6-phosphate dehydrogenase (G6PD) were mainly elevated in lungs and hearts of MsrA -/- mice. Moreover, the body weight of the MsrA -/- mice lagged behind the WT mice body weight up to 120 days of the SD diet. In summary, it is suggested that the lack of the MsrA gene in conjunction with prolonged SD diet causes decreased antioxidant capability and enhanced protein oxidation.
Collapse
Affiliation(s)
- J Moskovitz
- Department of Pharmacology and Toxicology, Pharmacy School, University of Kansas, Lawrence, KS 66045, USA.
| |
Collapse
|
|
16
|
Sagher D, Brunell D, Hejtmancik JF, Kantorow M, Brot N, Weissbach H. Thionein can serve as a reducing agent for the methionine sulfoxide reductases. Proc Natl Acad Sci U S A 2006; 103:8656-61. [PMID: 16735467 PMCID: PMC1592241 DOI: 10.1073/pnas.0602826103] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
It has been generally accepted, primarily from studies on methionine sulfoxide reductase (Msr) A, that the biological reducing agent for the members of the Msr family is reduced thioredoxin (Trx), although high levels of DTT can be used as the reductant in vitro. Preliminary experiments using both human recombinant MsrB2 (hMsrB2) and MsrB3 (hMsrB3) showed that although DTT can function in vitro as the reducing agent, Trx works very poorly, prompting a more careful comparison of the ability of DTT and Trx to function as reducing agents with the various members of the Msr family. Escherichia coli MsrA and MsrB and bovine MsrA efficiently use either Trx or DTT as reducing agents. In contrast, hMsrB2 and hMsrB3 show <10% of the activity with Trx as compared with DTT, raising the possibility that, in animal cells, Trx may not be the direct hydrogen donor or that there may be a Trx-independent reducing system required for MsrB2 and MsrB3 activity. A heat-stable protein has been detected in bovine liver that, in the presence of EDTA, can support the Msr reaction in the absence of either Trx or DTT. This protein has been identified as a zinc-containing metallothionein (Zn-MT). The results indicate that thionein (T), which is formed when the zinc is removed from Zn-MT, can function as a reducing system for the Msr proteins because of its high content of cysteine residues and that Trx can reduce oxidized T.
Collapse
Affiliation(s)
- Daphna Sagher
- *Center for Molecular Biology and Biotechnology, Florida Atlantic University, Boca Raton, FL 33431
| | - David Brunell
- *Center for Molecular Biology and Biotechnology, Florida Atlantic University, Boca Raton, FL 33431
| | - J. Fielding Hejtmancik
- Ophthalmic Genetic and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, MD 20892; and
| | - Marc Kantorow
- *Center for Molecular Biology and Biotechnology, Florida Atlantic University, Boca Raton, FL 33431
| | - Nathan Brot
- Department of Microbiology and Immunology, Hospital for Special Surgery, Cornell University Medical Center, New York, NY 10021
| | - Herbert Weissbach
- *Center for Molecular Biology and Biotechnology, Florida Atlantic University, Boca Raton, FL 33431
| |
Collapse
|
|
17
|
Kim HY, Gladyshev VN. Different catalytic mechanisms in mammalian selenocysteine- and cysteine-containing methionine-R-sulfoxide reductases. PLoS Biol 2005; 3:e375. [PMID: 16262444 PMCID: PMC1278935 DOI: 10.1371/journal.pbio.0030375] [Citation(s) in RCA: 130] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2005] [Accepted: 09/06/2005] [Indexed: 12/04/2022] Open
Abstract
Selenocysteine (Sec) is found in active sites of several oxidoreductases in which this residue is essential for catalytic activity. However, many selenoproteins have fully functional orthologs, wherein cysteine (Cys) occupies the position of Sec. The reason why some enzymes evolve into selenoproteins if the Cys versions may be sufficient is not understood. Among three mammalian methionine-R-sulfoxide reductases (MsrBs), MsrB1 is a Sec-containing protein, whereas MsrB2 and MsrB3 contain Cys in the active site, making these enzymes an excellent system for addressing the question of why Sec is used in biological systems. In this study, we found that residues, which are uniquely conserved in Cys-containing MsrBs and which are critical for enzyme activity in MsrB2 and MsrB3, were not required for MsrB1, but increased the activity of its Cys mutant. Conversely, selenoprotein MsrB1 had a unique resolving Cys reversibly engaged in the selenenylsulfide bond. However, this Cys was not necessary for activities of either MsrB2, MsrB3, or the Cys mutant of MsrB1. We prepared Sec-containing forms of MsrB2 and MsrB3 and found that they were more than 100-fold more active than the natural Cys forms. However, these selenoproteins could not be reduced by the physiological electron donor, thioredoxin. Yet, insertion of the resolving Cys, which was conserved in MsrB1, into the selenoprotein form of MsrB3 restored the thioredoxin-dependent activity of this enzyme. These data revealed differences in catalytic mechanisms between selenoprotein MsrB1 and non-selenoproteins MsrB2 and MsrB3, and identified catalytic advantages and disadvantages of Sec- and Cys-containing proteins. The data also suggested that Sec- and Cys-containing oxidoreductases require distinct sets of active-site features that maximize their catalytic efficiencies and provide strategies for protein design with improved catalytic properties. Altering cysteine-containing residues in a family of oxidoreductases reveals the role of selenocysteine in influencing the catalytic mechanism.
Collapse
Affiliation(s)
- Hwa-Young Kim
- 1Department of Biochemistry, University of Nebraska, Lincoln, Nebraska, United States of America
| | - Vadim N Gladyshev
- 1Department of Biochemistry, University of Nebraska, Lincoln, Nebraska, United States of America
| |
Collapse
|
|
18
|
Marchetti MA, Pizarro GO, Sagher D, DeAmicis C, Brot N, Hejtmancik JF, Weissbach H, Kantorow M. Methionine sulfoxide reductases B1, B2, and B3 are present in the human lens and confer oxidative stress resistance to lens cells. Invest Ophthalmol Vis Sci 2005; 46:2107-12. [PMID: 15914630 PMCID: PMC1351357 DOI: 10.1167/iovs.05-0018] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
PURPOSE Methionine-sulfoxide reductases are unique, in that their ability to repair oxidized proteins and MsrA, which reduces S-methionine sulfoxide, can protect lens cells against oxidative stress damage. To date, the roles of MsrB1, -B2 and -B3 which reduce R-methionine sulfoxide have not been established for any mammalian system. The present study was undertaken to identify those MsrBs expressed by the lens and to evaluate the enzyme activities, expression patterns, and abilities of the identified genes to defend lens cells against oxidative stress damage. METHODS Enzyme activities were determined with bovine lens extracts. The identities and spatial expression patterns of MsrB1, -B2, and -B3 transcripts were examined by RT-PCR in human lens and 21 other tissues. Oxidative stress resistance was measured using short interfering (si)RNA-mediated gene-silencing in conjunction with exposure to tert-butyl hydroperoxide (tBHP) and MTS viability measurements in SRA04/01 human lens epithelial cells. RESULTS Forty percent of the Msr enzyme activity present in the lens was MsrB, whereas the remaining enzyme activity was MsrA. MsrB1 (selenoprotein R, localized in the cytosol and nucleus), MsrB2 (CBS-1, localized in the mitochondria), and MsrB3 (localized in the endoplasmic reticulum and mitochondria) were all expressed by the lens. These genes exhibit asymmetric expression patterns between different human tissues and different lens sublocations, including lens fibers. All three genes are required for lens cell viability, and their silencing in lens cells results in increased oxidative-stress-induced cell death. CONCLUSIONS The present data suggest important roles for both MsrA and -Bs in lens cell viability and oxidative stress protection. The differential tissue distribution and lens expression patterns of these genes, coupled with increased oxidative-stress-induced cell death on their deletion provides evidence that they are important for lens cell function, resistance to oxidative stress, and, potentially, cataractogenesis.
Collapse
Affiliation(s)
| | | | - Daphna Sagher
- Center of Molecular Biology and Biotechnology, Florida Atlantic University, Boca Raton, Florida; the
| | | | - Nathan Brot
- Department of Microbiology and Immunology, Hospital for Special Surgery, Weill Medical College of Cornell University, New York, New York; and the
| | - J. Fielding Hejtmancik
- Ophthalmic Genetic and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland
| | - Herbert Weissbach
- Center of Molecular Biology and Biotechnology, Florida Atlantic University, Boca Raton, Florida; the
| | | |
Collapse
|
|
19
|
Hansel A, Heinemann SH, Hoshi T. Heterogeneity and function of mammalian MSRs: enzymes for repair, protection and regulation. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2005; 1703:239-47. [PMID: 15680232 DOI: 10.1016/j.bbapap.2004.09.010] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2004] [Revised: 09/10/2004] [Accepted: 09/13/2004] [Indexed: 01/15/2023]
Abstract
Methionine sulfoxide, the physiologically relevant oxidation product of methionine, is enzymatically reduced by peptide methionine sulfoxide reductases (MSRs). Two distinct classes of these enzymes, MSRA and MSRB, which selectively reduce the two methionine sulfoxide epimers, methionine-S-sulfoxide and methionine-R-sulfoxide, respectively, are found in virtually all organisms. Mammals typically possess only one gene encoding MSRA, but at least three genes encoding MSRBs. These MSRs show distinct tissue- and subcellular expression patterns and may play specific functional roles. Susceptibility of some ion channels to reversible methionine oxidation suggests that MSRs have a regulatory role in cellular excitability. Some--if not all--MSRs protect cells and organisms against a variety of oxidative stress episodes, including those by hypoxia and reperfusion, and play a modulatory role in lifespan determination. More MSR-dependent physiological phenomena await to be discovered.
Collapse
Affiliation(s)
- Alfred Hansel
- Molecular and Cellular Biophysics, Medical Faculty of the Friedrich Schiller University Jena, Drackendorfer Strasse 1, D-07747 Jena, Germany
| | | | | |
Collapse
|
|
20
|
Weissbach H, Resnick L, Brot N. Methionine sulfoxide reductases: history and cellular role in protecting against oxidative damage. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2004; 1703:203-12. [PMID: 15680228 DOI: 10.1016/j.bbapap.2004.10.004] [Citation(s) in RCA: 220] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2004] [Revised: 10/07/2004] [Accepted: 10/11/2004] [Indexed: 12/31/2022]
Abstract
An enzyme that can reduce methionine sulfoxide in proteins was first discovered in Escherichia coli about 25 years ago. It is now apparent that there is a family of enzymes, referred to as methionine sulfoxide reductases (Msr), and in recent years there has been considerable interest in one of the members of the Msr family, MsrA. This enzyme has been shown to protect cells against oxidative damage, which suggests a possible role in a large number of age-related diseases. This review summarizes the history of the discovery of MsrA, properties of the enzyme and its role in protecting cells against oxidative damage. Other members of the Msr family that differ in substrate specificity and localization are described as well as a possible role for the Msr system in drug metabolism. The concept that the Msr system can be used to develop novel drugs that could be catalytic anti-oxidants is discussed.
Collapse
Affiliation(s)
- Herbert Weissbach
- Center for Molecular Biology and Biotechnology, Florida Atlantic University, 777 Glades Road, Boca Raton, FL 33431, USA.
| | | | | |
Collapse
|
|
21
|
Etienne F, Resnick L, Sagher D, Brot N, Weissbach H. Reduction of Sulindac to its active metabolite, sulindac sulfide: assay and role of the methionine sulfoxide reductase system. Biochem Biophys Res Commun 2004; 312:1005-10. [PMID: 14651971 DOI: 10.1016/j.bbrc.2003.10.203] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Sulindac is a known anti-inflammatory drug that functions by inhibition of cyclooxygenases 1 and 2 (COX). There has been recent interest in Sulindac and other non-steroidal anti-inflammatory drugs (NSAID) because of their anti-tumor activity against colorectal cancer. Studies with sulindac have indicated that it may also function as an anti-tumor agent by stimulating apoptosis. Sulindac is a pro-drug, containing a methyl sulfoxide group, that must be reduced to sulindac sulfide to be active as a COX inhibitor. In the present studies we have developed a simple assay to measure sulindac reduction and tested sulindac as a substrate for 6 known members of the methionine sulfoxide reductase (Msr) family that have been identified in Escherichia coli. Only MsrA and a membrane associated Msr can reduce sulindac to the active sulfide. The reduction of sulindac also has been demonstrated in extracts of calf liver, kidney, and brain. Sulindac reductase activity is also present in mitochondria and microsomes.
Collapse
Affiliation(s)
- Frantzy Etienne
- Center for Molecular Biology and Biotechnology, Florida Atlantic University, Boca Raton, FL, USA
| | | | | | | | | |
Collapse
|
|
22
|
Kim HY, Gladyshev VN. Methionine sulfoxide reduction in mammals: characterization of methionine-R-sulfoxide reductases. Mol Biol Cell 2003; 15:1055-64. [PMID: 14699060 PMCID: PMC363075 DOI: 10.1091/mbc.e03-08-0629] [Citation(s) in RCA: 235] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Methionine residues in proteins are susceptible to oxidation by reactive oxygen species, but can be repaired via reduction of the resulting methionine sulfoxides by methionine-S-sulfoxide reductase (MsrA) and methionine-R-sulfoxide reductase (MsrB). However, the identity of all methionine sulfoxide reductases involved, their cellular locations and relative contributions to the overall pathway are poorly understood. Here, we describe a methionine-R-sulfoxide reduction system in mammals, in which two MsrB homologues were previously described. We found that human and mouse genomes possess three MsrB genes and characterized their protein products, designated MsrB1, MsrB2, and MsrB3. MsrB1 (Selenoprotein R) was present in the cytosol and nucleus and exhibited the highest methionine-R-sulfoxide reductase activity because of the presence of selenocysteine (Sec) in its active site. Other mammalian MsrBs contained cysteine in place of Sec and were less catalytically efficient. MsrB2 (CBS-1) resided in mitochondria. It had high affinity for methionine-R-sulfoxide, but was inhibited by higher concentrations of the substrate. The human MsrB3 gene gave rise to two protein forms, MsrB3A and MsrB3B. These were generated by alternative splicing that introduced contrasting N-terminal and C-terminal signals, such that MsrB3A was targeted to the endoplasmic reticulum and MsrB3B to mitochondria. We found that only mitochondrial forms of mammalian MsrBs (MsrB2 and MsrB3B) could compensate for MsrA and MsrB deficiency in yeast. All mammalian MsrBs belonged to a group of zinc-containing proteins. The multiplicity of MsrBs contrasted with the presence of a single mammalian MsrA gene as well as with the occurrence of single MsrA and MsrB genes in yeast, fruit flies, and nematodes. The data suggested that different cellular compartments in mammals maintain a system for repair of oxidized methionine residues and that this function is tuned in enzyme- and stereo-specific manner.
Collapse
Affiliation(s)
- Hwa-Young Kim
- Department of Biochemistry, University of Nebraska, Lincoln, Nebraska 68588, USA
| | | |
Collapse
|
|
23
|
Spector D, Etienne F, Brot N, Weissbach H. New membrane-associated and soluble peptide methionine sulfoxide reductases in Escherichia coli. Biochem Biophys Res Commun 2003; 302:284-9. [PMID: 12604343 DOI: 10.1016/s0006-291x(03)00163-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
It is known that reactive oxygen species can oxidize methionine residues in proteins in a non-stereospecific manner, and cells have mechanisms to reverse this damage. MsrA and MsrB are members of the methionine sulfoxide family of enzymes that specifically reduce the S and R forms, respectively, of methionine sulfoxide in proteins. However, in Escherichia coli the level of MsrB activity is very low which suggested that there may be other enzymes capable of reducing the R epimer of methionine sulfoxide in proteins. Employing a msrA/B double mutant, a new peptide methionine sulfoxide reductase activity has been found associated with membrane vesicles from E. coli. Both the R and S forms of N-acetylmethionine sulfoxide, D-ala-met(o)-enkephalin and methionine sulfoxide, are reduced by this membrane associated activity. The reaction requires NADPH and may explain, in part, how the R form of methionine sulfoxide in proteins is reduced in E. coli. In addition, a new soluble Msr activity was also detected in the soluble extracts of the double mutant that specifically reduces the S epimer of met(o) in proteins.
Collapse
Affiliation(s)
- Daniel Spector
- Center for Molecular Biology and Biotechnology, Florida Atlantic University, Boca Raton, FL 33431, USA
| | | | | | | |
Collapse
|
|
24
|
Etienne F, Spector D, Brot N, Weissbach H. A methionine sulfoxide reductase in Escherichia coli that reduces the R enantiomer of methionine sulfoxide. Biochem Biophys Res Commun 2003; 300:378-82. [PMID: 12504094 DOI: 10.1016/s0006-291x(02)02870-x] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
It is known that Escherichia coli methionine mutants can grow on both enantiomers of methionine sulfoxide (met(o)), i.e., met-R-(o) or met-S-(o), indicating the presence of enzymes in E. coli that can reduce each of these enantiomers to methionine (met). Previous studies have identified two members of the methionine sulfoxide reductase (Msr) family of enzymes, MsrA and fSMsr, that could reduce free met-S-(o), but the reduction of free met-R-(o) to met has not been elucidated. One possible candidate is MsrB which is known to reduce met-R-(o) in proteins to met. However, free met-R-(o) is a very poor substrate for MsrB and the level of MsrB activity in E. coli extracts is very low. A new member of the Msr family (fRMsr) has been identified in E. coli extracts that reduces free met-R-(o) to met. Partial purification of FRMsr has been obtained using extracts from an MsrA/MsrB double mutant of E. coli.
Collapse
Affiliation(s)
- Frantzy Etienne
- Center for Molecular Biology and Biotechnology, Florida Atlantic University, 777 Glades Road, Boca Raton, FL 33431, USA
| | | | | | | |
Collapse
|
|
25
|
Bar-Noy S, Moskovitz J. Mouse methionine sulfoxide reductase B: effect of selenocysteine incorporation on its activity and expression of the seleno-containing enzyme in bacterial and mammalian cells. Biochem Biophys Res Commun 2002; 297:956-61. [PMID: 12359247 DOI: 10.1016/s0006-291x(02)02314-8] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The mammalian methionine sulfoxide reductase B (MsrB) has been found to be a selenoprotein which can reduce R form of both free and protein-incorporated methionine sulfoxide to methionine. Together with MsrA, which reduces specifically the S form of methionine sulfoxide, the living cell can repair methionine-damaged proteins and salvage free methionine under oxidative stress conditions. Here, we report about the pivotal role of the selenocysteine residue in the protein putative active site by site-directed mutagenesis directed to the selenocysteine codon. Using the Escherichia coli SECIS (selenocysteine insertion sequence) element, needed for the recognition of the UGA codon as a selenocysteine codon in E. coli, we expressed the seleno-MsrB as a recombinant selenoprotein in E. coli. The recombinant seleno-MsrB has been shown to be much more active than the cysteine mutant, whereas the mutations to alanine and serine rendered the protein inactive. Although the yields of expression of the full-length N-terminus and C-terminus His-tagged seleno-MsrB were only 3% (of the total MsrB expressed), the C-terminus His-tagged protein enabled us to get a pure preparation of the seleno-MsrB. Using both recombinant selenoproteins, the N-terminus His-tagged and the C-terminus His-tagged proteins, we were able to determine the specific activities of the recombinant seleno-MsrB, which were found to be much higher than the cysteine mutant homologue. This finding confirmed our suggestion that the selenocysteine is essential for maintaining high reducing activity of MsrB. In addition, using radioactive selenium we were able to determine the in vivo presence of MsrB as a selenoprotein in mammalian cell cultures.
Collapse
Affiliation(s)
- Shoshana Bar-Noy
- Laboratory of Biochemistry, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | | |
Collapse
|
|
26
|
Jung S, Hansel A, Kasperczyk H, Hoshi T, Heinemann SH. Activity, tissue distribution and site-directed mutagenesis of a human peptide methionine sulfoxide reductase of type B: hCBS1. FEBS Lett 2002; 527:91-4. [PMID: 12220640 DOI: 10.1016/s0014-5793(02)03171-x] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Human CBS1 is a methionine sulfoxide reductase of type B (MSRB) as it specifically reduced Met-R-SO in peptides with dithiothreitol or the thioredoxin system as reductants. Mutation C169S in the active site completely abolished enzymatic activity, while mutation W110A only reduced activity and C105S had no effect. Like human MSRA, hCBS1 showed in vivo reducing activity coexpressed with the Drosophila ShC/B potassium channel in oocytes, by accelerating the overall inactivation time course. hCBS1-encoding mRNA is most abundant in muscle tissues, especially in the heart and thereby shows an expression pattern different to the human MSRA.
Collapse
Affiliation(s)
- Stephan Jung
- Molecular and Cellular Biophysics, Medical Faculty of the Friedrich Schiller University Jena, Drackendorfer St. 1, D-07747, Jena, Germany
| | | | | | | | | |
Collapse
|
|
27
|
Hansel A, Kuschel L, Hehl S, Lemke C, Agricola HJ, Hoshi T, Heinemann SH. Mitochondrial targeting of the human peptide methionine sulfoxide reductase (MSRA), an enzyme involved in the repair of oxidized proteins. FASEB J 2002; 16:911-3. [PMID: 12039877 DOI: 10.1096/fj.01-0737fje] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Peptide methionine sulfoxide reductase (MSRA) catalyzes the reduction of methionine sulfoxide to methionine. This widely expressed enzyme constitutes an important repair mechanism for oxidatively damaged proteins, which accumulate during the manifestation of certain degenerative diseases and aging processes. In addition, it is discussed to be involved in regulatory processes. Here we address the question of how the enzyme's diverse functions are reflected in its subcellular localization. Using fusions of the human version of MSRA with the enhanced green fluorescence protein expressed in various mammalian cell lines, we show a distinct localization at mitochondria. The N-terminal 23 amino acid residues contain the signal for this mitochondrial targeting. Activity tests showed that they are not required for enzyme function. Mitochondrial localization of native MSRA in mouse and rat liver slices was verified with an MSRA-specific antibody by using immunohistochemical methods. The protein was located in the mitochondrial matrix, as demonstrated by using pre-embedding immunostaining and electron microscopy. Mitochondria are the major source of reactive oxygen species (ROS). Therefore, MSRA has to be considered an important means for the general reduction of ROS release from mitochondria.
Collapse
Affiliation(s)
- Alfred Hansel
- Molecular and Cellular Biophysics, Medical Faculty of the Friedrich Schiller University Jena, D-07747 Jena, Germany
| | | | | | | | | | | | | |
Collapse
|
|
28
|
Weissbach H, Etienne F, Hoshi T, Heinemann SH, Lowther WT, Matthews B, St John G, Nathan C, Brot N. Peptide methionine sulfoxide reductase: structure, mechanism of action, and biological function. Arch Biochem Biophys 2002; 397:172-8. [PMID: 11795868 DOI: 10.1006/abbi.2001.2664] [Citation(s) in RCA: 250] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Reactive oxygen and nitrogen intermediates can cause damage to many cellular components and have been implicated in a number of diseases. Cells have developed a variety of mechanisms to destroy these reactive molecules or repair the damage once it occurs. In proteins one of the amino acids most easily oxidized is methionine, which is converted to methionine sulfoxide. An enzyme, peptide methionine sulfoxide reductase (MsrA), catalyzes the reduction of methionine sulfoxide in proteins back to methionine. There is growing evidence that MsrA plays an important role in protecting cells against oxidative damage. This paper reviews the biochemical properties and biological role of MsrA.
Collapse
Affiliation(s)
- Herbert Weissbach
- Center for Molecular Biology and Biotechnology, Florida Atlantic University, Boca Raton, Florida 33431, USA.
| | | | | | | | | | | | | | | | | |
Collapse
|