1
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How an assembly factor enhances covalent FAD attachment to the flavoprotein subunit of complex II. J Biol Chem 2022; 298:102472. [PMID: 36089066 PMCID: PMC9557727 DOI: 10.1016/j.jbc.2022.102472] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Revised: 08/31/2022] [Accepted: 09/02/2022] [Indexed: 01/25/2023] Open
Abstract
The membrane-bound complex II family of proteins is composed of enzymes that catalyze succinate and fumarate interconversion coupled with reduction or oxidation of quinones within the membrane domain. The majority of complex II enzymes are protein heterotetramers with the different subunits harboring a variety of redox centers. These redox centers are used to transfer electrons between the site of succinate-fumarate oxidation/reduction and the membrane domain harboring the quinone. A covalently bound FAD cofactor is present in the flavoprotein subunit, and the covalent flavin linkage is absolutely required to enable the enzyme to oxidize succinate. Assembly of the covalent flavin linkage in eukaryotic cells and many bacteria requires additional protein assembly factors. Here, we provide mechanistic details for how the assembly factors work to enhance covalent flavinylation. Both prokaryotic SdhE and mammalian SDHAF2 enhance FAD binding to their respective apoprotein of complex II. These assembly factors also increase the affinity for dicarboxylates to the apoprotein-noncovalent FAD complex and stabilize the preassembly complex. These findings are corroborated by previous investigations of the roles of SdhE in enhancing covalent flavinylation in both bacterial succinate dehydrogenase and fumarate reductase flavoprotein subunits and of SDHAF2 in performing the same function for the human mitochondrial succinate dehydrogenase flavoprotein. In conclusion, we provide further insight into assembly factor involvement in building complex II flavoprotein subunit active site required for succinate oxidation.
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2
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Maklashina E. Structural Insight into Evolution of the Quinone Binding Site in Complex II. BIOCHEMISTRY. BIOKHIMIIA 2022; 87:752-761. [PMID: 36171656 DOI: 10.1134/s0006297922080077] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Revised: 06/09/2022] [Accepted: 06/10/2022] [Indexed: 06/16/2023]
Abstract
The Complex II family encompasses membrane bound succinate:quinones reductases and quinol:fumarate reductases that catalyze interconversion of succinate and fumarate coupled with reduction and oxidation of quinone. These enzymes are found in all biological genres and share a modular structure where a highly conserved soluble domain is bound to a membrane-spanning domain that is represented by distinct variations. The current classification of the complex II family members is based on the number of subunits and co-factors in the membrane anchor (types A-F). This classification also provides insights into possible evolutionary paths and suggests that some of the complex II enzymes (types A-C) co-evolved as the whole assembly. Origin of complex II types D and F may have arisen from independent events of de novo association of the conserved soluble domain with a new anchor. Here we analyze a recent structure of Mycobacterium smegmatis Sdh2, a complex II enzyme with two transmembrane subunits and two heme b molecules. This analysis supports an earlier hypothesis suggesting that mitochondrial complex II (type C) with a single heme b may have evolved as an assembled unit from an ancestor similar to M. smegmatis Sdh2.
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Affiliation(s)
- Elena Maklashina
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94143, USA.
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3
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The roles of SDHAF2 and dicarboxylate in covalent flavinylation of SDHA, the human complex II flavoprotein. Proc Natl Acad Sci U S A 2020; 117:23548-23556. [PMID: 32887801 DOI: 10.1073/pnas.2007391117] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Mitochondrial complex II, also known as succinate dehydrogenase (SDH), is an integral-membrane heterotetramer (SDHABCD) that links two essential energy-producing processes, the tricarboxylic acid (TCA) cycle and oxidative phosphorylation. A significant amount of information is available on the structure and function of mature complex II from a range of organisms. However, there is a gap in our understanding of how the enzyme assembles into a functional complex, and disease-associated complex II insufficiency may result from incorrect function of the mature enzyme or from assembly defects. Here, we investigate the assembly of human complex II by combining a biochemical reconstructionist approach with structural studies. We report an X-ray structure of human SDHA and its dedicated assembly factor SDHAF2. Importantly, we also identify a small molecule dicarboxylate that acts as an essential cofactor in this process and works in synergy with SDHAF2 to properly orient the flavin and capping domains of SDHA. This reorganizes the active site, which is located at the interface of these domains, and adjusts the pKa of SDHAR451 so that covalent attachment of the flavin adenine dinucleotide (FAD) cofactor is supported. We analyze the impact of disease-associated SDHA mutations on assembly and identify four distinct conformational forms of the complex II flavoprotein that we assign to roles in assembly and catalysis.
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4
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Gong P, Lei P, Wang S, Zeng A, Lou H. Post-Translational Modifications Aid Archaeal Survival. Biomolecules 2020; 10:biom10040584. [PMID: 32290118 PMCID: PMC7226565 DOI: 10.3390/biom10040584] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 04/03/2020] [Accepted: 04/04/2020] [Indexed: 12/22/2022] Open
Abstract
Since the pioneering work of Carl Woese, Archaea have fascinated biologists of almost all areas given their unique evolutionary status, wide distribution, high diversity, and ability to grow in special environments. Archaea often thrive in extreme conditions such as high temperature, high/low pH, high salinity, and anoxic ecosystems. All of these are threats to the stability and proper functioning of biological molecules, especially proteins and nucleic acids. Post-translational modifications (PTMs), such as phosphorylation, methylation, acetylation, and glycosylation, are reportedly widespread in Archaea and represent a critical adaptive mechanism to extreme habitats. Here, we summarize our current understanding of the contributions of PTMs to aid in extremophile survival, with a particular focus on the maintenance of genome stability.
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Affiliation(s)
- Ping Gong
- Hunan Institute of Microbiology, Changsha 410009, China; (P.L.); (S.W.); (A.Z.)
- Correspondence: (P.G.); (H.L.)
| | - Ping Lei
- Hunan Institute of Microbiology, Changsha 410009, China; (P.L.); (S.W.); (A.Z.)
| | - Shengping Wang
- Hunan Institute of Microbiology, Changsha 410009, China; (P.L.); (S.W.); (A.Z.)
| | - Ao Zeng
- Hunan Institute of Microbiology, Changsha 410009, China; (P.L.); (S.W.); (A.Z.)
| | - Huiqiang Lou
- State Key Laboratory of Agro-Biotechnology and Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Biological Sciences, China Agricultural University, No.2 Yuan-Ming-Yuan West Road, Beijing 100193, China
- Correspondence: (P.G.); (H.L.)
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5
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Moosavi B, Berry EA, Zhu XL, Yang WC, Yang GF. The assembly of succinate dehydrogenase: a key enzyme in bioenergetics. Cell Mol Life Sci 2019; 76:4023-4042. [PMID: 31236625 PMCID: PMC11105593 DOI: 10.1007/s00018-019-03200-7] [Citation(s) in RCA: 65] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2019] [Revised: 05/30/2019] [Accepted: 06/17/2019] [Indexed: 12/12/2022]
Abstract
Succinate dehydrogenase (SDH) also known as complex II or succinate:quinone oxidoreductase is an enzyme involved in both oxidative phosphorylation and tricarboxylic acid cycle; the processes that generate energy. SDH is a multi-subunit enzyme which requires a series of proteins for its proper assembly at several steps. This enzyme has medical significance as there is a broad range of human diseases from cancers to neurodegeneration related to SDH malfunction. Some of these disorders have recently been linked to defective assembly factors, reinvigorating further research in this area. Apart from that this enzyme has agricultural importance as many fungicides have been/will be designed targeting specifically this enzyme in plant fungal pathogens. In addition, we speculate it might be possible to design novel fungicides specifically targeting fungal assembly factors. Considering the medical and agricultural implications of SDH, the aim of this review is an overview of the SDH assembly factors and critical analysis of controversial issues around them.
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Affiliation(s)
- Behrooz Moosavi
- Key Laboratory of Pesticide and Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, Wuhan, 430079, People's Republic of China
| | - Edward A Berry
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, 13210, USA
| | - Xiao-Lei Zhu
- Key Laboratory of Pesticide and Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, Wuhan, 430079, People's Republic of China
| | - Wen-Chao Yang
- Key Laboratory of Pesticide and Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, Wuhan, 430079, People's Republic of China
| | - Guang-Fu Yang
- Key Laboratory of Pesticide and Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, Wuhan, 430079, People's Republic of China.
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6
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Huang S, Braun HP, Gawryluk RMR, Millar AH. Mitochondrial complex II of plants: subunit composition, assembly, and function in respiration and signaling. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2019; 98:405-417. [PMID: 30604579 DOI: 10.1111/tpj.14227] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Revised: 12/20/2018] [Accepted: 12/21/2018] [Indexed: 05/20/2023]
Abstract
Complex II [succinate dehydrogenase (succinate-ubiquinone oxidoreductase); EC 1.3.5.1; SDH] is the only enzyme shared by both the electron transport chain and the tricarboxylic acid (TCA) cycle in mitochondria. Complex II in plants is considered unusual because of its accessory subunits (SDH5-SDH8), in addition to the catalytic subunits of SDH found in all eukaryotes (SDH1-SDH4). Here, we review compositional and phylogenetic analysis and biochemical dissection studies to both clarify the presence and propose a role for these subunits. We also consider the wider functional and phylogenetic evidence for SDH assembly factors and the reports from plants on the control of SDH1 flavination and SDH1-SDH2 interaction. Plant complex II has been shown to influence stomatal opening, the plant defense response and reactive oxygen species-dependent stress responses. Signaling molecules such as salicyclic acid (SA) and nitric oxide (NO) are also reported to interact with the ubiquinone (UQ) binding site of SDH, influencing signaling transduction in plants. Future directions for SDH research in plants and the specific roles of its different subunits and assembly factors are suggested, including the potential for reverse electron transport to explain the succinate-dependent production of reactive oxygen species in plants and new avenues to explore the evolution of plant mitochondrial complex II and its utility.
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Affiliation(s)
- Shaobai Huang
- School of Molecular Sciences & ARC Centre of Excellence in Plant Energy Biology, The University of Western Australia, 6009, Crawley, WA, Australia
| | - Hans-Peter Braun
- Institute of Plant Genetics, Leibniz Universität Hannover, 30419, Hannover, Germany
| | | | - A Harvey Millar
- School of Molecular Sciences & ARC Centre of Excellence in Plant Energy Biology, The University of Western Australia, 6009, Crawley, WA, Australia
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7
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Wong HS, Benoit B, Brand MD. Mitochondrial and cytosolic sources of hydrogen peroxide in resting C2C12 myoblasts. Free Radic Biol Med 2019; 130:140-150. [PMID: 30389498 DOI: 10.1016/j.freeradbiomed.2018.10.448] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Revised: 10/27/2018] [Accepted: 10/29/2018] [Indexed: 10/28/2022]
Abstract
The relative contributions of different mitochondrial and cytosolic sources of superoxide and hydrogen peroxide in cells are not well established because of a lack of suitable quantitative assays. To address this problem using resting C2C12 myoblasts we measured the effects of specific inhibitors that do not affect other pathways on the rate of appearance of hydrogen peroxide in the extracellular medium. We used inhibitors of NADPH oxidases (NOXs), suppressors of site IQ electron leak (S1QELs) at mitochondrial Complex I, and suppressors of site IIIQo electron leak (S3QELs) at mitochondrial Complex III. Around 40% of net cellular hydrogen peroxide release was from NOXs and approximately 45% was from the two mitochondrial sites; 30% from site IIIQo and 15% from site IQ. As expected, decreasing cytosolic antioxidant capacity by lowering glutathione levels increased the absolute rates from all sites without changing their proportions, whereas decreasing antioxidant defenses in the mitochondrial matrix increased only the absolute and relative contributions of the two mitochondrial sites. These results show directly that mitochondria are a major contributor to cytosolic hydrogen peroxide in resting C2C12 myoblasts, and provide the first direct evidence of superoxide/hydrogen peroxide production from site IQ in unstressed cells.
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Affiliation(s)
- Hoi-Shan Wong
- Buck Institute for Research on Aging, 8001 Redwood Blvd, Novato, CA 94945, USA.
| | - Bérengère Benoit
- Buck Institute for Research on Aging, 8001 Redwood Blvd, Novato, CA 94945, USA.
| | - Martin D Brand
- Buck Institute for Research on Aging, 8001 Redwood Blvd, Novato, CA 94945, USA.
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8
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Crystal structure of bacterial succinate:quinone oxidoreductase flavoprotein SdhA in complex with its assembly factor SdhE. Proc Natl Acad Sci U S A 2018. [PMID: 29514959 DOI: 10.1073/pnas.1800195115] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Succinate:quinone oxidoreductase (SQR) functions in energy metabolism, coupling the tricarboxylic acid cycle and electron transport chain in bacteria and mitochondria. The biogenesis of flavinylated SdhA, the catalytic subunit of SQR, is assisted by a highly conserved assembly factor termed SdhE in bacteria via an unknown mechanism. By using X-ray crystallography, we have solved the structure of Escherichia coli SdhE in complex with SdhA to 2.15-Å resolution. Our structure shows that SdhE makes a direct interaction with the flavin adenine dinucleotide-linked residue His45 in SdhA and maintains the capping domain of SdhA in an "open" conformation. This displaces the catalytic residues of the succinate dehydrogenase active site by as much as 9.0 Å compared with SdhA in the assembled SQR complex. These data suggest that bacterial SdhE proteins, and their mitochondrial homologs, are assembly chaperones that constrain the conformation of SdhA to facilitate efficient flavinylation while regulating succinate dehydrogenase activity for productive biogenesis of SQR.
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9
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Sharma P, Maklashina E, Cecchini G, Iverson TM. Crystal structure of an assembly intermediate of respiratory Complex II. Nat Commun 2018; 9:274. [PMID: 29348404 PMCID: PMC5773532 DOI: 10.1038/s41467-017-02713-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Accepted: 12/20/2017] [Indexed: 02/06/2023] Open
Abstract
Flavin is covalently attached to the protein scaffold in ~10% of flavoenzymes. However, the mechanism of covalent modification is unclear, due in part to challenges in stabilizing assembly intermediates. Here, we capture the structure of an assembly intermediate of the Escherichiacoli Complex II (quinol:fumarate reductase (FrdABCD)). The structure contains the E. coli FrdA subunit bound to covalent FAD and crosslinked with its assembly factor, SdhE. The structure contains two global conformational changes as compared to prior structures of the mature protein: the rotation of a domain within the FrdA subunit, and the destabilization of two large loops of the FrdA subunit, which may create a tunnel to the active site. We infer a mechanism for covalent flavinylation. As supported by spectroscopic and kinetic analyses, we suggest that SdhE shifts the conformational equilibrium of the FrdA active site to disfavor succinate/fumarate interconversion and enhance covalent flavinylation. The mechanism for covalent flavinylation of flavoenzymes is still unclear. Here, the authors propose a mechanism based on the crystal structure of a flavinylation assembly intermediate of the E. coli respiratory Complex II comprising the E. coli FrdA subunit bound to covalent FAD and crosslinked with its assembly factor SdhE.
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Affiliation(s)
- Pankaj Sharma
- Department of Pharmacology, Vanderbilt University, Nashville, TN, 37232, USA
| | - Elena Maklashina
- Molecular Biology Division, San Francisco VA Health Care System, San Francisco, CA, 94121, USA.,Department of Biochemistry & Biophysics, University of California, San Francisco, CA, 94158, USA
| | - Gary Cecchini
- Molecular Biology Division, San Francisco VA Health Care System, San Francisco, CA, 94121, USA. .,Department of Biochemistry & Biophysics, University of California, San Francisco, CA, 94158, USA.
| | - T M Iverson
- Department of Pharmacology, Vanderbilt University, Nashville, TN, 37232, USA. .,Department of Biochemistry, Vanderbilt University, Nashville, TN, 37232, USA. .,Center for Structural Biology, Vanderbilt University, Nashville, TN, 37232, USA. .,Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN, 37232, USA.
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10
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Starbird CA, Maklashina E, Sharma P, Qualls-Histed S, Cecchini G, Iverson TM. Structural and biochemical analyses reveal insights into covalent flavinylation of the Escherichia coli Complex II homolog quinol:fumarate reductase. J Biol Chem 2017; 292:12921-12933. [PMID: 28615448 DOI: 10.1074/jbc.m117.795120] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Revised: 06/07/2017] [Indexed: 11/06/2022] Open
Abstract
The Escherichia coli Complex II homolog quinol:fumarate reductase (QFR, FrdABCD) catalyzes the interconversion of fumarate and succinate at a covalently attached FAD within the FrdA subunit. The SdhE assembly factor enhances covalent flavinylation of Complex II homologs, but the mechanisms underlying the covalent attachment of FAD remain to be fully elucidated. Here, we explored the mechanisms of covalent flavinylation of the E. coli QFR FrdA subunit. Using a ΔsdhE E. coli strain, we show that the requirement for the assembly factor depends on the cellular redox environment. We next identified residues important for the covalent attachment and selected the FrdAE245 residue, which contributes to proton shuttling during fumarate reduction, for detailed biophysical and structural characterization. We found that QFR complexes containing FrdAE245Q have a structure similar to that of the WT flavoprotein, but lack detectable substrate binding and turnover. In the context of the isolated FrdA subunit, the anticipated assembly intermediate during covalent flavinylation, FrdAE245 variants had stability similar to that of WT FrdA, contained noncovalent FAD, and displayed a reduced capacity to interact with SdhE. However, small-angle X-ray scattering (SAXS) analysis of WT FrdA cross-linked to SdhE suggested that the FrdAE245 residue is unlikely to contribute directly to the FrdA-SdhE protein-protein interface. We also found that no auxiliary factor is absolutely required for flavinylation, indicating that the covalent flavinylation is autocatalytic. We propose that multiple factors, including the SdhE assembly factor and bound dicarboxylates, stimulate covalent flavinylation by preorganizing the active site to stabilize the quinone-methide intermediate.
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Affiliation(s)
- C A Starbird
- Graduate Program in Chemical and Physical Biology, Vanderbilt University, Nashville, Tennessee 37232
| | - Elena Maklashina
- Molecular Biology Division, Veterans Affairs Medical Center, San Francisco, California 94121; Department of Biochemistry and Biophysics, University of California, San Francisco, California 94158
| | - Pankaj Sharma
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee 37232
| | - Susan Qualls-Histed
- Departments of Cell and Developmental Biology, Vanderbilt University, Nashville, Tennessee 37232
| | - Gary Cecchini
- Molecular Biology Division, Veterans Affairs Medical Center, San Francisco, California 94121; Department of Biochemistry and Biophysics, University of California, San Francisco, California 94158.
| | - T M Iverson
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee 37232; Department of Biochemistry, Vanderbilt University, Nashville, Tennessee 37232; Center for Structural Biology, Vanderbilt University, Nashville, Tennessee 37232; Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37232.
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11
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Bezawork-Geleta A, Rohlena J, Dong L, Pacak K, Neuzil J. Mitochondrial Complex II: At the Crossroads. Trends Biochem Sci 2017; 42:312-325. [PMID: 28185716 DOI: 10.1016/j.tibs.2017.01.003] [Citation(s) in RCA: 172] [Impact Index Per Article: 24.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2016] [Revised: 01/06/2017] [Accepted: 01/10/2017] [Indexed: 02/06/2023]
Abstract
Mitochondrial complex II (CII), also called succinate dehydrogenase (SDH), is a central purveyor of the reprogramming of metabolic and respiratory adaptation in response to various intrinsic and extrinsic stimuli and abnormalities. In this review we discuss recent findings regarding SDH biogenesis, which requires four known assembly factors, and modulation of its enzymatic activity by acetylation, succinylation, phosphorylation, and proteolysis. We further focus on the emerging role of both genetic and epigenetic aberrations leading to SDH dysfunction associated with various clinical manifestations. This review also covers the recent discovery of the role of SDH in inflammation-linked pathologies. Conceivably, SDH is a potential target for several hard-to-treat conditions, including cancer, that remains to be fully exploited.
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Affiliation(s)
| | - Jakub Rohlena
- Institute of Biotechnology, Czech Academy of Sciences, Prague, Czechia
| | - Lanfeng Dong
- School of Medical Science, Griffith University, Southport, Australia
| | - Karel Pacak
- Section on Medical Neuroendocrinology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Jiri Neuzil
- School of Medical Science, Griffith University, Southport, Australia; Institute of Biotechnology, Czech Academy of Sciences, Prague, Czechia.
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12
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Bezawork-Geleta A, Dong L, Rohlena J, Neuzil J. The Assembly Factor SDHAF2 Is Dispensable for Flavination of the Catalytic Subunit of Mitochondrial Complex II in Breast Cancer Cells. J Biol Chem 2016; 291:21414-21420. [PMID: 27587393 DOI: 10.1074/jbc.c116.755017] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Revised: 08/27/2016] [Indexed: 12/19/2022] Open
Abstract
Mitochondrial complex II or succinate dehydrogenase (SDH) is at the crossroads of oxidative phosphorylation and the tricarboxylic acid cycle. It has been shown that Sdh5 (SDHAF2/SDH5 in mammals) is required for flavination of the subunit Sdh1 (SDHA in human cells) in yeast. Here we demonstrate that in human breast cancer cells, SDHAF2/SDH5 is dispensable for SDHA flavination. In contrast to yeast, CRISPR-Cas9 nickase-mediated SDHAF2 KO breast cancer cells feature flavinated SDHA and retain fully assembled and functional complex II, as well as normal mitochondrial respiration. Our data show that SDHA flavination is independent of SDHAF2 in breast cancer cells, employing an alternative mechanism.
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Affiliation(s)
| | - Lanfeng Dong
- From the School of Medical Science, Griffith University, Southport, 4222 Queensland, Australia and
| | - Jakub Rohlena
- the Institute of Biotechnology, Czech Academy of Sciences, 252 50 Prague-West, Czech Republic
| | - Jiri Neuzil
- From the School of Medical Science, Griffith University, Southport, 4222 Queensland, Australia and .,the Institute of Biotechnology, Czech Academy of Sciences, 252 50 Prague-West, Czech Republic
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13
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Maklashina E, Rajagukguk S, Starbird CA, McDonald WH, Koganitsky A, Eisenbach M, Iverson TM, Cecchini G. Binding of the Covalent Flavin Assembly Factor to the Flavoprotein Subunit of Complex II. J Biol Chem 2015; 291:2904-16. [PMID: 26644464 DOI: 10.1074/jbc.m115.690396] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2015] [Indexed: 01/23/2023] Open
Abstract
Escherichia coli harbors two highly conserved homologs of the essential mitochondrial respiratory complex II (succinate:ubiquinone oxidoreductase). Aerobically the bacterium synthesizes succinate:quinone reductase as part of its respiratory chain, whereas under microaerophilic conditions, the quinol:fumarate reductase can be utilized. All complex II enzymes harbor a covalently bound FAD co-factor that is essential for their ability to oxidize succinate. In eukaryotes and many bacteria, assembly of the covalent flavin linkage is facilitated by a small protein assembly factor, termed SdhE in E. coli. How SdhE assists with formation of the covalent flavin bond and how it binds the flavoprotein subunit of complex II remain unknown. Using photo-cross-linking, we report the interaction site between the flavoprotein of complex II and the SdhE assembly factor. These data indicate that SdhE binds to the flavoprotein between two independently folded domains and that this binding mode likely influences the interdomain orientation. In so doing, SdhE likely orients amino acid residues near the dicarboxylate and FAD binding site, which facilitates formation of the covalent flavin linkage. These studies identify how the conserved SdhE assembly factor and its homologs participate in complex II maturation.
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Affiliation(s)
- Elena Maklashina
- From the Molecular Biology Division, Veterans Affairs Medical Center, San Francisco, California 94121, the Department of Biochemistry & Biophysics, University of California, San Francisco, California 94158
| | - Sany Rajagukguk
- From the Molecular Biology Division, Veterans Affairs Medical Center, San Francisco, California 94121
| | | | - W Hayes McDonald
- the Department of Biochemistry and Mass Spectrometry Research Center
| | - Anna Koganitsky
- the Department of Biological Chemistry, Weizmann Institute of Science, 76100 Rehovot, Israel
| | - Michael Eisenbach
- the Department of Biological Chemistry, Weizmann Institute of Science, 76100 Rehovot, Israel
| | - Tina M Iverson
- the Department of Biochemistry and Mass Spectrometry Research Center, the Department of Pharmacology, the Center for Structural Biology, and the Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37232, and
| | - Gary Cecchini
- From the Molecular Biology Division, Veterans Affairs Medical Center, San Francisco, California 94121, the Department of Biochemistry & Biophysics, University of California, San Francisco, California 94158,
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14
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Van Vranken JG, Na U, Winge DR, Rutter J. Protein-mediated assembly of succinate dehydrogenase and its cofactors. Crit Rev Biochem Mol Biol 2014; 50:168-80. [PMID: 25488574 DOI: 10.3109/10409238.2014.990556] [Citation(s) in RCA: 75] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Succinate dehydrogenase (or complex II; SDH) is a heterotetrameric protein complex that links the tribarboxylic acid cycle with the electron transport chain. SDH is composed of four nuclear-encoded subunits that must translocate independently to the mitochondria and assemble into a mature protein complex embedded in the inner mitochondrial membrane. Recently, it has become clear that failure to assemble functional SDH complexes can result in cancer and neurodegenerative syndromes. The effort to thoroughly elucidate the SDH assembly pathway has resulted in the discovery of four subunit-specific assembly factors that aid in the maturation of individual subunits and support the assembly of the intact complex. This review will focus on these assembly factors and assess the contribution of each factor to the assembly of SDH. Finally, we propose a model of the SDH assembly pathway that incorporates all extant data.
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