1
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Dieckmann CL. A hub for regulation of mitochondrial metabolism: Fatty acid and lipoic acid biosynthesis. IUBMB Life 2024; 76:332-344. [PMID: 38088214 DOI: 10.1002/iub.2802] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Accepted: 11/21/2023] [Indexed: 05/28/2024]
Abstract
Having evolved from a prokaryotic origin, mitochondria retain pathways required for the catabolism of energy-rich molecules and for the biosynthesis of molecules that aid catabolism and/or participate in other cellular processes essential for life of the cell. Reviewed here are details of the mitochondrial fatty acid biosynthetic pathway (FAS II) and its role in building both the octanoic acid precursor for lipoic acid biosynthesis (LAS) and longer-chain fatty acids functioning in chaperoning the assembly of mitochondrial multisubunit complexes. Also covered are the details of mitochondrial lipoic acid biosynthesis, which is distinct from that of prokaryotes, and the attachment of lipoic acid to subunits of pyruvate dehydrogenase, α-ketoglutarate dehydrogenase, and glycine cleavage system complexes. Special emphasis has been placed on presenting what is currently known about the interconnected paths and loops linking the FAS II-LAS pathway and two other mitochondrial realms, the organellar translation machinery and Fe-S cluster biosynthesis and function.
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Affiliation(s)
- Carol L Dieckmann
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, Arizona, USA
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2
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Wedan RJ, Longenecker JZ, Nowinski SM. Mitochondrial fatty acid synthesis is an emergent central regulator of mammalian oxidative metabolism. Cell Metab 2024; 36:36-47. [PMID: 38128528 PMCID: PMC10843818 DOI: 10.1016/j.cmet.2023.11.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Revised: 11/27/2023] [Accepted: 11/30/2023] [Indexed: 12/23/2023]
Abstract
Contrary to their well-known functions in nutrient breakdown, mitochondria are also important biosynthetic hubs and express an evolutionarily conserved mitochondrial fatty acid synthesis (mtFAS) pathway. mtFAS builds lipoic acid and longer saturated fatty acids, but its exact products, their ultimate destination in cells, and the cellular significance of the pathway are all active research questions. Moreover, why mitochondria need mtFAS despite their well-defined ability to import fatty acids is still unclear. The identification of patients with inborn errors of metabolism in mtFAS genes has sparked fresh research interest in the pathway. New mammalian models have provided insights into how mtFAS coordinates many aspects of oxidative mitochondrial metabolism and raise questions about its role in diseases such as obesity, diabetes, and heart failure. In this review, we discuss the products of mtFAS, their function, and the consequences of mtFAS impairment across models and in metabolic disease.
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Affiliation(s)
- Riley J Wedan
- Department of Metabolism and Nutritional Programming, The Van Andel Institute, Grand Rapids, MI 49503, USA; College of Human Medicine, Michigan State University, Grand Rapids, MI 49503, USA
| | - Jacob Z Longenecker
- Department of Metabolism and Nutritional Programming, The Van Andel Institute, Grand Rapids, MI 49503, USA
| | - Sara M Nowinski
- Department of Metabolism and Nutritional Programming, The Van Andel Institute, Grand Rapids, MI 49503, USA.
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3
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Rahman MT, Koski MK, Panecka-Hofman J, Schmitz W, Kastaniotis AJ, Wade RC, Wierenga RK, Hiltunen JK, Autio KJ. An engineered variant of MECR reductase reveals indispensability of long-chain acyl-ACPs for mitochondrial respiration. Nat Commun 2023; 14:619. [PMID: 36739436 PMCID: PMC9899272 DOI: 10.1038/s41467-023-36358-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Accepted: 01/25/2023] [Indexed: 02/06/2023] Open
Abstract
Mitochondrial fatty acid synthesis (mtFAS) is essential for respiratory function. MtFAS generates the octanoic acid precursor for lipoic acid synthesis, but the role of longer fatty acid products has remained unclear. The structurally well-characterized component of mtFAS, human 2E-enoyl-ACP reductase (MECR) rescues respiratory growth and lipoylation defects of a Saccharomyces cerevisiae Δetr1 strain lacking native mtFAS enoyl reductase. To address the role of longer products of mtFAS, we employed in silico molecular simulations to design a MECR variant with a shortened substrate binding cavity. Our in vitro and in vivo analyses indicate that the MECR G165Q variant allows synthesis of octanoyl groups but not long chain fatty acids, confirming the validity of our computational approach to engineer substrate length specificity. Furthermore, our data imply that restoring lipoylation in mtFAS deficient yeast strains is not sufficient to support respiration and that long chain acyl-ACPs generated by mtFAS are required for mitochondrial function.
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Affiliation(s)
- M Tanvir Rahman
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland
| | | | - Joanna Panecka-Hofman
- Faculty of Physics, University of Warsaw, Warsaw, Poland
- Molecular and Cellular Modeling Group, Heidelberg Institute for Theoretical Studies (HITS), Heidelberg, Germany
| | - Werner Schmitz
- Faculty of Biochemistry and Molecular Biology, University of Würzburg, Würzburg, Germany
| | | | - Rebecca C Wade
- Molecular and Cellular Modeling Group, Heidelberg Institute for Theoretical Studies (HITS), Heidelberg, Germany
- Zentrum für Molekulare Biologie (ZMBH), DKFZ-ZMBH Alliance and Interdisciplinary Center for Scientific Computing (IWR), Heidelberg University, Heidelberg, Germany
| | - Rik K Wierenga
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland
| | - J Kalervo Hiltunen
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland
| | - Kaija J Autio
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland.
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4
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Wang K, Li L, Jin J, An Y, Wang Z, Zhou S, Zhang J, Abuduaini B, Cheng C, Li N. Fatty acid synthase (Fasn) inhibits the expression levels of immune response genes via alteration of alternative splicing in islet cells. J Diabetes Complications 2022; 36:108159. [PMID: 35210136 DOI: 10.1016/j.jdiacomp.2022.108159] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/10/2021] [Revised: 12/17/2021] [Accepted: 02/11/2022] [Indexed: 10/19/2022]
Abstract
BACKGROUND Increasing evidence has shown that fatty acid synthase (Fasn) is associated with diabetes mellitus (DM) and insulin resistance, however, it remains unclear how Fasn upregulation leads to dysregulation of energy homeostasis in islet cells. Consequently, uncovering the function of Fasn in islet cells. Consequently, uncovering the function of FASN in islet cells is immensely important for finding a treatment target. AIM In this study, we elucidated the biological function of Fasn on the target genes in a rat insulinoma INS-1 cell line. METHODS We created a Fasn overexpressing rat insulinoma cell line (Fasn-OE), and performed bulk RNA-sequencing (RNA-seq) experiments on Fasn-OE and INS-1 (control) cells. We first identified differentially expressed genes (DEGs) using Bioconductor package edgeR, and then discovered enriched gene ontology terms and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways using the KEGG Orthology Based Annotation System (KOBAS) 2.0 web server. Furthermore, we identified alternative splicing events (ASEs) and regulated alternative splicing events (RASEs) by applying the ABLas pipeline. The reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was used for validation of selected differentially expressed genes (DEGs) and Fasn-regulated alternative splicing genes (RASGs). RESULTS In this study we found that Fasn overexpression led to significant changes of gene expression profiles, including downregulations of mRNA levels of immune related genes, including Bst2, Ddit3, Isg15, Mx2, Oas1a, Oasl, and RT1-S3 in INS-1 cell line. Furthermore, Fasn positively regulated the expression of transcription factors such as Fat1 and Ncl diabetes-related genes. Importantly, Fasn overexpression to result in alternative splicing events including in a metabolism-associated ATP binding protein mRNA Abcc5. In Gene Ontology analysis, the downregulated genes in Fasn-OE cells were mainly enriched in inflammatory response and innate immune response. In Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, the downregulated genes were mainly enriched in TNF signaling pathway and cytokine-mediated signaling pathways. CONCLUSIONS Our findings showed that upregulation of Fasn may play a critical role in islet cell immunmetabolism via modifications of immune/inflammatory related genes on transcription and alternative splicing level, which provide novel insights into characterizing the function of Fasn in islet cell immunity and for the development of chemo/immune therapies.
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Affiliation(s)
- Kunling Wang
- Department of Traditional Chinese Medicine, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, Xinjiang 830054, PR China
| | - Lin Li
- Department of Molecular Biology, Xinjiang Medical University, Urumqi, Xinjiang 830054, PR China
| | - Jing Jin
- Department of Traditional Chinese Medicine, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, Xinjiang 830054, PR China
| | - Yanli An
- Department of Traditional Chinese Medicine, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, Xinjiang 830054, PR China
| | - Zhongjuan Wang
- Department of Traditional Chinese Medicine, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, Xinjiang 830054, PR China
| | - Shiying Zhou
- Department of Traditional Chinese Medicine, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, Xinjiang 830054, PR China
| | - Jiyuan Zhang
- The First Clinical Institute of Xinjiang Medical University
| | - Buzukela Abuduaini
- Department of Intensive Care Unit, The First Affiliated Hospital of Xinjiang Medical University.
| | - Chao Cheng
- ABLife BioBigData Institute, Wuhan, Hubei, 430075, China
| | - Ning Li
- ABLife BioBigData Institute, Wuhan, Hubei, 430075, China
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5
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Serum Metabolomic Analysis of Male Patients with Cannabis or Amphetamine Use Disorder. Metabolites 2022; 12:metabo12020179. [PMID: 35208253 PMCID: PMC8879674 DOI: 10.3390/metabo12020179] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 02/01/2022] [Accepted: 02/08/2022] [Indexed: 02/04/2023] Open
Abstract
Studies have demonstrated that chronic consumption of abused drugs induces alterations in several proteins that regulate metabolism. For instance, methamphetamine exposure reduces glucose levels. Fatty and amino acid levels were altered in groups exposed to abused drugs. Therefore, in our study, we investigated the serum metabolomic profile of patients diagnosed with cannabis and/or amphetamine use disorders. Blood was obtained from subjects (control, amphetamine, and cannabis). Detection of serum metabolites was performed using gas chromatography. The ratio peak areas for metabolites were analyzed across the three groups. Both cannabis and amphetamine groups showed higher d-erythrotetrafuranose, octadecanoic acid, hexadecenoic acid, trans-9-octadecanoic acid, lactic acid and methyl thio hydantoin metabolites compared with the control group. Moreover, cannabis patients were found to possess higher glycine, 9,12 octadecanoic acid malonic acid, phosphoric acid and prostaglandin F1a than controls. Our analysis showed that the identified metabolic profile of cannabis or amphetamine use disorder patients was different than control group. Our data indicated that chronic exposure to cannabis or amphetamine dysregulated metabolites in the serum. Future studies are warranted to explore the effects of these abused drugs on the metabolic proteins.
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6
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Prevalence of elevated serum fatty acid synthase in chronic limb-threatening ischemia. Sci Rep 2021; 11:19272. [PMID: 34588500 PMCID: PMC8481229 DOI: 10.1038/s41598-021-98479-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Accepted: 08/30/2021] [Indexed: 11/10/2022] Open
Abstract
There are currently no serum-based evaluations that can corroborate the severity of peripheral artery disease (PAD). In this cross-sectional study, we assessed the prevalence of elevated serum fatty acid synthase (cFAS) in patients with chronic limb-threatening ischemia (CLTI) and evaluated the accuracy of its use in detecting this condition. Preoperative fasting serum samples from 87 patients undergoing vascular intervention were collected between October 2014 and September 2016. Median age was 62 years, with 56 (64%) men, and 32 (37%) with CLTI. We found that elevated cFAS content (OR 1.17; 95% CI 1.04–1.31), type 2 diabetes (T2D; OR 5.22; 95% CI 1.77–15.4), and smoking (OR 3.53; 95% CI 1.19–10.5) were independently associated with CLTI and could detect the presence of CLTI with 83% accuracy (95% CI 0.74–0.92). Furthermore, serum FAS content was positively correlated with FAS content in femoral artery plaque in patients with severe PAD (\documentclass[12pt]{minimal}
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\begin{document}$${R}^{2}$$\end{document}R2 = 0.22; P = 0.023). Finally, significantly higher co-localization of FAS and ApoB were observed within lower extremity arterial media (P < .001). Our findings indicate that serum FAS content is a marker for disease severity in patients with PAD, independent of concomitant T2D and smoking, and may play a key role in FAS and ApoB peripheral plaque progression.
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7
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Jiang D, Liu C, Chen Y, Xing X, Zheng D, Guo Z, Lin S. Metabolomics Study of Whole-body Vibration on Lipid Metabolism of Skeletal Muscle in Aging Mice. Int J Sports Med 2020; 42:464-477. [PMID: 33124015 DOI: 10.1055/a-1268-8458] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Ageing increases the occurrence and development of many diseases. Exercise is believed to be an effective way to improve ageing and skeletal muscle atrophy. However, many elderly people are unable to engage in active exercise. Whole-body vibration is a passive way of moving that is especially suitable for the elderly and people who find it inconvenient to exercise. Metabolomics is the systematic study of metabolic changes in small molecules. In this study, metabolomics studies were performed to investigate the regulatory effect of whole-body vibration on the skeletal muscles of ageing mice. After 12 weeks, we found that whole-body vibration had the most obvious effect on lipid metabolism pathways (such as linoleic acid, α-linolenic acid metabolism, glycerophospholipid metabolism pathways) in skeletal muscle of ageing mice. Through further research we found that whole-body vibration decreased the levels of triglycerides, total cholesterol, low-density lipoprotein cholesterol and very low-density lipoprotein in blood; decreased the lipid deposition in skeletal muscle; decreased the protein expression of monocyte chemoattractant protein-1 and interleukin-6; improved the protein levels of phosphorylated insulin receptor substrate-1, phosphate phosphoinositide 3-kinase and p-AKT; improved the protein levels of klotho; and decreased the protein expression of p53. These findings reveal that whole-body vibration might postpone senility by attenuating lipid deposition and reducing chronic inflammation and the insulin resistance of skeletal muscle.
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Affiliation(s)
- Dingwen Jiang
- The First Affiliated Hospital of Jinan University, Jinan University, Guangzhou.,Department of Endocrinology, First Affiliated Hospital of Jinzhou Medical University, Jinzhou
| | - Chang Liu
- Department of Endocrinology, First Affiliated Hospital of Jinzhou Medical University, Jinzhou
| | - Ye Chen
- College of Mechanical Engineering and Automation, Liaoning University of Technology, Jinzhou
| | - Xuejiao Xing
- Department of Endocrinology, First Affiliated Hospital of Jinzhou Medical University, Jinzhou
| | - Danmeng Zheng
- Department of Endocrinology, First Affiliated Hospital of Jinzhou Medical University, Jinzhou
| | - Zhanpeng Guo
- Department of Orthopedics, First Affiliated Hospital of Jinzhou Medical University, Jinzhou
| | - Sen Lin
- Department of Orthopedics, First Affiliated Hospital of Jinzhou Medical University, Jinzhou
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8
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Nowinski SM, Solmonson A, Rusin SF, Maschek JA, Bensard CL, Fogarty S, Jeong MY, Lettlova S, Berg JA, Morgan JT, Ouyang Y, Naylor BC, Paulo JA, Funai K, Cox JE, Gygi SP, Winge DR, DeBerardinis RJ, Rutter J. Mitochondrial fatty acid synthesis coordinates oxidative metabolism in mammalian mitochondria. eLife 2020; 9:58041. [PMID: 32804083 PMCID: PMC7470841 DOI: 10.7554/elife.58041] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Accepted: 08/15/2020] [Indexed: 12/13/2022] Open
Abstract
Cells harbor two systems for fatty acid synthesis, one in the cytoplasm (catalyzed by fatty acid synthase, FASN) and one in the mitochondria (mtFAS). In contrast to FASN, mtFAS is poorly characterized, especially in higher eukaryotes, with the major product(s), metabolic roles, and cellular function(s) being essentially unknown. Here we show that hypomorphic mtFAS mutant mouse skeletal myoblast cell lines display a severe loss of electron transport chain (ETC) complexes and exhibit compensatory metabolic activities including reductive carboxylation. This effect on ETC complexes appears to be independent of protein lipoylation, the best characterized function of mtFAS, as mutants lacking lipoylation have an intact ETC. Finally, mtFAS impairment blocks the differentiation of skeletal myoblasts in vitro. Together, these data suggest that ETC activity in mammals is profoundly controlled by mtFAS function, thereby connecting anabolic fatty acid synthesis with the oxidation of carbon fuels.
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Affiliation(s)
| | - Ashley Solmonson
- Children's Medical Center Research Institute, University of Texas Southwestern Medical Center, Dallas, United States
| | - Scott F Rusin
- Department of Cell Biology, Harvard University School of Medicine, Boston, United States
| | - J Alan Maschek
- Diabetes & Metabolism Research Center, Salt Lake City, United States.,Department of Nutrition and Integrative Physiology, Salt Lake City, United States.,Metabolomics, Proteomics and Mass Spectrometry Core Research Facilities University of Utah, Salt Lake City, United States
| | | | - Sarah Fogarty
- Department of Biochemistry, Salt Lake City, United States.,Howard Hughes Medical Institute, Salt Lake City, United States
| | - Mi-Young Jeong
- Department of Biochemistry, Salt Lake City, United States
| | | | - Jordan A Berg
- Department of Biochemistry, Salt Lake City, United States
| | - Jeffrey T Morgan
- Department of Biochemistry, Salt Lake City, United States.,Howard Hughes Medical Institute, Salt Lake City, United States
| | - Yeyun Ouyang
- Department of Biochemistry, Salt Lake City, United States
| | - Bradley C Naylor
- Metabolomics, Proteomics and Mass Spectrometry Core Research Facilities University of Utah, Salt Lake City, United States
| | - Joao A Paulo
- Department of Cell Biology, Harvard University School of Medicine, Boston, United States
| | - Katsuhiko Funai
- Diabetes & Metabolism Research Center, Salt Lake City, United States
| | - James E Cox
- Department of Biochemistry, Salt Lake City, United States.,Diabetes & Metabolism Research Center, Salt Lake City, United States.,Metabolomics, Proteomics and Mass Spectrometry Core Research Facilities University of Utah, Salt Lake City, United States
| | - Steven P Gygi
- Department of Cell Biology, Harvard University School of Medicine, Boston, United States
| | - Dennis R Winge
- Department of Biochemistry, Salt Lake City, United States.,Diabetes & Metabolism Research Center, Salt Lake City, United States.,Department of Internal Medicine, Salt Lake City, United States
| | - Ralph J DeBerardinis
- Children's Medical Center Research Institute, University of Texas Southwestern Medical Center, Dallas, United States.,Howard Hughes Medical Institute, Salt Lake City, United States
| | - Jared Rutter
- Department of Biochemistry, Salt Lake City, United States.,Diabetes & Metabolism Research Center, Salt Lake City, United States.,Howard Hughes Medical Institute, Salt Lake City, United States
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9
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Trefely S, Lovell CD, Snyder NW, Wellen KE. Compartmentalised acyl-CoA metabolism and roles in chromatin regulation. Mol Metab 2020; 38:100941. [PMID: 32199817 PMCID: PMC7300382 DOI: 10.1016/j.molmet.2020.01.005] [Citation(s) in RCA: 140] [Impact Index Per Article: 35.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Revised: 01/03/2020] [Accepted: 01/07/2020] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Many metabolites serve as important signalling molecules to adjust cellular activities and functions based on nutrient availability. Links between acetyl-CoA metabolism, histone lysine acetylation, and gene expression have been documented and studied over the past decade. In recent years, several additional acyl modifications to histone lysine residues have been identified, which depend on acyl-coenzyme A thioesters (acyl-CoAs) as acyl donors. Acyl-CoAs are intermediates of multiple distinct metabolic pathways, and substantial evidence has emerged that histone acylation is metabolically sensitive. Nevertheless, the metabolic sources of acyl-CoAs used for chromatin modification in most cases remain poorly understood. Elucidating how these diverse chemical modifications are coupled to and regulated by cellular metabolism is important in deciphering their functional significance. SCOPE OF REVIEW In this article, we review the metabolic pathways that produce acyl-CoAs, as well as emerging evidence for functional roles of diverse acyl-CoAs in chromatin regulation. Because acetyl-CoA has been extensively reviewed elsewhere, we will focus on four other acyl-CoA metabolites integral to major metabolic pathways that are also known to modify histones: succinyl-CoA, propionyl-CoA, crotonoyl-CoA, and butyryl-CoA. We also briefly mention several other acyl-CoA species, which present opportunities for further research; malonyl-CoA, glutaryl-CoA, 3-hydroxybutyryl-CoA, 2-hydroxyisobutyryl-CoA, and lactyl-CoA. Each acyl-CoA species has distinct roles in metabolism, indicating the potential to report shifts in the metabolic status of the cell. For each metabolite, we consider the metabolic pathways in which it participates and the nutrient sources from which it is derived, the compartmentalisation of its metabolism, and the factors reported to influence its abundance and potential nuclear availability. We also highlight reported biological functions of these metabolically-linked acylation marks. Finally, we aim to illuminate key questions in acyl-CoA metabolism as they relate to the control of chromatin modification. MAJOR CONCLUSIONS A majority of acyl-CoA species are annotated to mitochondrial metabolic processes. Since acyl-CoAs are not known to be directly transported across mitochondrial membranes, they must be synthesized outside of mitochondria and potentially within the nucleus to participate in chromatin regulation. Thus, subcellular metabolic compartmentalisation likely plays a key role in the regulation of histone acylation. Metabolite tracing in combination with targeting of relevant enzymes and transporters will help to map the metabolic pathways that connect acyl-CoA metabolism to chromatin modification. The specific function of each acyl-CoA may be determined in part by biochemical properties that affect its propensity for enzymatic versus non-enzymatic protein modification, as well as the various enzymes that can add, remove and bind each modification. Further, competitive and inhibitory effects of different acyl-CoA species on these enzymes make determining the relative abundance of acyl-CoA species in specific contexts important to understand the regulation of chromatin acylation. An improved and more nuanced understanding of metabolic regulation of chromatin and its roles in physiological and disease-related processes will emerge as these questions are answered.
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Affiliation(s)
- Sophie Trefely
- Department of Cancer Biology, University of Pennsylvania, Philadelphia, PA 19104, USA; Abramson Family Cancer Research Institute, University of Pennsylvania, Philadelphia, PA 19104, USA; Center for Metabolic Disease Research, Department of Microbiology and Immunology, Lewis Katz School of Medicine, Temple University, Philadelphia, PA 19140, USA
| | - Claudia D Lovell
- Department of Cancer Biology, University of Pennsylvania, Philadelphia, PA 19104, USA; Abramson Family Cancer Research Institute, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Nathaniel W Snyder
- Center for Metabolic Disease Research, Department of Microbiology and Immunology, Lewis Katz School of Medicine, Temple University, Philadelphia, PA 19140, USA.
| | - Kathryn E Wellen
- Department of Cancer Biology, University of Pennsylvania, Philadelphia, PA 19104, USA; Abramson Family Cancer Research Institute, University of Pennsylvania, Philadelphia, PA 19104, USA.
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10
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Kastaniotis AJ, Autio KJ, R Nair R. Mitochondrial Fatty Acids and Neurodegenerative Disorders. Neuroscientist 2020; 27:143-158. [PMID: 32644907 DOI: 10.1177/1073858420936162] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Fatty acids in mitochondria, in sensu stricto, arise either as β-oxidation substrates imported via the carnitine shuttle or through de novo synthesis by the mitochondrial fatty acid synthesis (mtFAS) pathway. Defects in mtFAS or processes involved in the generation of the mtFAS product derivative lipoic acid (LA), including iron-sulfur cluster synthesis required for functional LA synthase, have emerged only recently as etiology for neurodegenerative disease. Intriguingly, mtFAS deficiencies very specifically affect CNS function, while LA synthesis and attachment defects have a pleiotropic presentation beyond neurodegeneration. Typical mtFAS defect presentations include optical atrophy, as well as basal ganglia defects associated with dystonia. The phenotype display of patients with mtFAS defects can resemble the presentation of disorders associated with coenzyme A (CoA) synthesis. A recent publication links these processes together based on the requirement of CoA for acyl carrier protein maturation. MtFAS defects, CoA synthesis- as well as Fe-S cluster-deficiencies share lack of LA as a common symptom.
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Affiliation(s)
| | - Kaija J Autio
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland
| | - Remya R Nair
- Mammalian Genetics Unit, MRC Harwell Institute, Oxfordshire, UK
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11
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Mitochondrial OXPHOS Biogenesis: Co-Regulation of Protein Synthesis, Import, and Assembly Pathways. Int J Mol Sci 2020; 21:ijms21113820. [PMID: 32481479 PMCID: PMC7312649 DOI: 10.3390/ijms21113820] [Citation(s) in RCA: 69] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 05/21/2020] [Accepted: 05/25/2020] [Indexed: 02/07/2023] Open
Abstract
The assembly of mitochondrial oxidative phosphorylation (OXPHOS) complexes is an intricate process, which—given their dual-genetic control—requires tight co-regulation of two evolutionarily distinct gene expression machineries. Moreover, fine-tuning protein synthesis to the nascent assembly of OXPHOS complexes requires regulatory mechanisms such as translational plasticity and translational activators that can coordinate mitochondrial translation with the import of nuclear-encoded mitochondrial proteins. The intricacy of OXPHOS complex biogenesis is further evidenced by the requirement of many tightly orchestrated steps and ancillary factors. Early-stage ancillary chaperones have essential roles in coordinating OXPHOS assembly, whilst late-stage assembly factors—also known as the LYRM (leucine–tyrosine–arginine motif) proteins—together with the mitochondrial acyl carrier protein (ACP)—regulate the incorporation and activation of late-incorporating OXPHOS subunits and/or co-factors. In this review, we describe recent discoveries providing insights into the mechanisms required for optimal OXPHOS biogenesis, including the coordination of mitochondrial gene expression with the availability of nuclear-encoded factors entering via mitochondrial protein import systems.
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12
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Cronan JE. Progress in the Enzymology of the Mitochondrial Diseases of Lipoic Acid Requiring Enzymes. Front Genet 2020; 11:510. [PMID: 32508887 PMCID: PMC7253636 DOI: 10.3389/fgene.2020.00510] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Accepted: 04/27/2020] [Indexed: 12/12/2022] Open
Abstract
Three human mitochondrial diseases that directly affect lipoic acid metabolism result from heterozygous missense and nonsense mutations in the LIAS, LIPT1, and LIPT2 genes. However, the functions of the proteins encoded by these genes in lipoic acid metabolism remained uncertain due to a lack of biochemical analysis at the enzyme level. An exception was the LIPT1 protein for which a perplexing property had been reported, a ligase lacking the ability to activate its substrate. This led to several models, some contradictory, to accommodate the role of LIPT1 protein activity in explaining the phenotypes of the afflicted neonatal patients. Recent evidence indicates that this LIPT1 protein activity is a misleading evolutionary artifact and that the physiological role of LIPT1 is in transfer of lipoic acid moieties from one protein to another. This and other new biochemical data now define a straightforward pathway that fully explains each of the human disorders specific to the assembly of lipoic acid on its cognate enzyme proteins.
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Affiliation(s)
- John E Cronan
- B103 Chemical and Life Sciences Laboratory, Departments of Microbiology and Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL, United States
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13
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Bunik VI. Redox-Driven Signaling: 2-Oxo Acid Dehydrogenase Complexes as Sensors and Transmitters of Metabolic Imbalance. Antioxid Redox Signal 2019; 30:1911-1947. [PMID: 30187773 DOI: 10.1089/ars.2017.7311] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
SIGNIFICANCE This article develops a holistic view on production of reactive oxygen species (ROS) by 2-oxo acid dehydrogenase complexes. Recent Advances: Catalytic and structural properties of the complexes and their components evolved to minimize damaging effects of side reactions, including ROS generation, simultaneously exploiting the reactions for homeostatic signaling. CRITICAL ISSUES Side reactions of the complexes, characterized in vitro, are analyzed in view of protein interactions and conditions in vivo. Quantitative data support prevalence of the forward 2-oxo acid oxidation over the backward NADH oxidation in feeding physiologically significant ROS production by the complexes. Special focus on interactions between the active sites within 2-oxo acid dehydrogenase complexes highlights the central relevance of the complex-bound thiyl radicals in regulation of and signaling by complex-generated ROS. The thiyl radicals arise when dihydrolipoyl residues of the complexes regenerate FADH2 from the flavin semiquinone coproduced with superoxide anion radical in 1e- oxidation of FADH2 by molecular oxygen. FUTURE DIRECTIONS Interaction of 2-oxo acid dehydrogenase complexes with thioredoxins (TRXs), peroxiredoxins, and glutaredoxins mediates scavenging of the thiyl radicals and ROS generated by the complexes, underlying signaling of disproportional availability of 2-oxo acids, CoA, and NAD+ in key metabolic branch points through thiol/disulfide exchange and medically important hypoxia-inducible factor, mammalian target of rapamycin (mTOR), poly (ADP-ribose) polymerase, and sirtuins. High reactivity of the coproduced ROS and thiyl radicals to iron/sulfur clusters and nitric oxide, peroxynitrite reductase activity of peroxiredoxins and transnitrosylating function of thioredoxin, implicate the side reactions of 2-oxo acid dehydrogenase complexes in nitric oxide-dependent signaling and damage.
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Affiliation(s)
- Victoria I Bunik
- 1 Belozersky Institute of Physicochemical Biology, Lomonosov Moscow State University, Moscow, Russian Federation.,2 Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, Russian Federation
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Zhu Y, Zhou P, Zhang L, Li J, Gao F, Zhou G. Effects of dietary crude protein levels and cysteamine supplementation on meat quality and related indices of finishing pigs. CANADIAN JOURNAL OF ANIMAL SCIENCE 2019. [DOI: 10.1139/cjas-2016-0095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The aim of this study was to investigate the effects of dietary crude protein levels and cysteamine (CS) supplementation on meat quality and related indices in longissimus dorsi muscle of finishing pigs. One hundred and twenty barrows were randomly allocated to a 2 × 2 factorial arrangement with five replicates of six pigs each. The primary variations were crude protein levels (14% or 10%) and CS supplemental levels (0 or 140 mg kg−1). After 41 d, 10 pigs per treatment were slaughtered. The results showed that low-protein level diets (LPDs) decreased Warner–Bratzler shear force (P < 0.01) and increased the content of intramuscular fat (P < 0.01). The mRNA expressions of lipogenic genes were up-regulated (P < 0.01), and the mRNA expressions of lipolytic genes were down-regulated (P < 0.01) in pigs fed LPD. LPDs increased the mRNA expressions of μ-calpain, and decreased the mRNA expression of calpastatin (P < 0.01). In addition, CS supplementation increased the mRNA expression of μ-calpain (P < 0.01). In conclusion, LPD improved the meat quality probably through regulating the lipogenesis, lipolysis, and the proteolysis process in muscle. The CS supplementation did not affect the meat quality of finishing pigs. Moreover, no significant interaction between dietary protein levels and CS supplementation for the meat quality of finishing pigs was observed.
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Affiliation(s)
- Y.P. Zhu
- College of Animal Science and Technology, Key Laboratory of Animal Origin Food Production and Safety Guarantee of Jiangsu Province, Jiangsu Collaborative Innovation Center of Meat Production and Processing, Quality and Safety Control, Nanjing Agricultural University, Nanjing 210095, People’s Republic of China
- College of Animal Science and Technology, Key Laboratory of Animal Origin Food Production and Safety Guarantee of Jiangsu Province, Jiangsu Collaborative Innovation Center of Meat Production and Processing, Quality and Safety Control, Nanjing Agricultural University, Nanjing 210095, People’s Republic of China
| | - P. Zhou
- College of Animal Science and Technology, Key Laboratory of Animal Origin Food Production and Safety Guarantee of Jiangsu Province, Jiangsu Collaborative Innovation Center of Meat Production and Processing, Quality and Safety Control, Nanjing Agricultural University, Nanjing 210095, People’s Republic of China
- College of Animal Science and Technology, Key Laboratory of Animal Origin Food Production and Safety Guarantee of Jiangsu Province, Jiangsu Collaborative Innovation Center of Meat Production and Processing, Quality and Safety Control, Nanjing Agricultural University, Nanjing 210095, People’s Republic of China
| | - L. Zhang
- College of Animal Science and Technology, Key Laboratory of Animal Origin Food Production and Safety Guarantee of Jiangsu Province, Jiangsu Collaborative Innovation Center of Meat Production and Processing, Quality and Safety Control, Nanjing Agricultural University, Nanjing 210095, People’s Republic of China
- College of Animal Science and Technology, Key Laboratory of Animal Origin Food Production and Safety Guarantee of Jiangsu Province, Jiangsu Collaborative Innovation Center of Meat Production and Processing, Quality and Safety Control, Nanjing Agricultural University, Nanjing 210095, People’s Republic of China
| | - J.L. Li
- College of Animal Science and Technology, Key Laboratory of Animal Origin Food Production and Safety Guarantee of Jiangsu Province, Jiangsu Collaborative Innovation Center of Meat Production and Processing, Quality and Safety Control, Nanjing Agricultural University, Nanjing 210095, People’s Republic of China
- College of Animal Science and Technology, Key Laboratory of Animal Origin Food Production and Safety Guarantee of Jiangsu Province, Jiangsu Collaborative Innovation Center of Meat Production and Processing, Quality and Safety Control, Nanjing Agricultural University, Nanjing 210095, People’s Republic of China
| | - F. Gao
- College of Animal Science and Technology, Key Laboratory of Animal Origin Food Production and Safety Guarantee of Jiangsu Province, Jiangsu Collaborative Innovation Center of Meat Production and Processing, Quality and Safety Control, Nanjing Agricultural University, Nanjing 210095, People’s Republic of China
- College of Animal Science and Technology, Key Laboratory of Animal Origin Food Production and Safety Guarantee of Jiangsu Province, Jiangsu Collaborative Innovation Center of Meat Production and Processing, Quality and Safety Control, Nanjing Agricultural University, Nanjing 210095, People’s Republic of China
| | - G.H. Zhou
- College of Animal Science and Technology, Key Laboratory of Animal Origin Food Production and Safety Guarantee of Jiangsu Province, Jiangsu Collaborative Innovation Center of Meat Production and Processing, Quality and Safety Control, Nanjing Agricultural University, Nanjing 210095, People’s Republic of China
- College of Animal Science and Technology, Key Laboratory of Animal Origin Food Production and Safety Guarantee of Jiangsu Province, Jiangsu Collaborative Innovation Center of Meat Production and Processing, Quality and Safety Control, Nanjing Agricultural University, Nanjing 210095, People’s Republic of China
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15
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Protein moonlighting elucidates the essential human pathway catalyzing lipoic acid assembly on its cognate enzymes. Proc Natl Acad Sci U S A 2018; 115:E7063-E7072. [PMID: 29987032 DOI: 10.1073/pnas.1805862115] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The lack of attachment of lipoic acid to its cognate enzyme proteins results in devastating human metabolic disorders. These mitochondrial disorders are evident soon after birth and generally result in early death. The mutations causing specific defects in lipoyl assembly map in three genes, LIAS, LIPT1, and LIPT2 Although physiological roles have been proposed for the encoded proteins, only the LIPT1 protein had been studied at the enzyme level. LIPT1 was reported to catalyze only the second partial reaction of the classical lipoate ligase mechanism. We report that the physiologically relevant LIPT1 enzyme activity is transfer of lipoyl moieties from the H protein of the glycine cleavage system to the E2 subunits of the 2-oxoacid dehydrogenases required for respiration (e.g., pyruvate dehydrogenase) and amino acid degradation. We also report that LIPT2 encodes an octanoyl transferase that initiates lipoyl group assembly. The human pathway is now biochemically defined.
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16
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Crooks DR, Maio N, Lane AN, Jarnik M, Higashi RM, Haller RG, Yang Y, Fan TWM, Linehan WM, Rouault TA. Acute loss of iron-sulfur clusters results in metabolic reprogramming and generation of lipid droplets in mammalian cells. J Biol Chem 2018. [PMID: 29523684 DOI: 10.1074/jbc.ra118.001885] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Iron-sulfur (Fe-S) clusters are ancient cofactors in cells and participate in diverse biochemical functions, including electron transfer and enzymatic catalysis. Although cell lines derived from individuals carrying mutations in the Fe-S cluster biogenesis pathway or siRNA-mediated knockdown of the Fe-S assembly components provide excellent models for investigating Fe-S cluster formation in mammalian cells, these experimental strategies focus on the consequences of prolonged impairment of Fe-S assembly. Here, we constructed and expressed dominant-negative variants of the primary Fe-S biogenesis scaffold protein iron-sulfur cluster assembly enzyme 2 (ISCU2) in human HEK293 cells. This approach enabled us to study the early metabolic reprogramming associated with loss of Fe-S-containing proteins in several major cellular compartments. Using multiple metabolomics platforms, we observed a ∼12-fold increase in intracellular citrate content in Fe-S-deficient cells, a surge that was due to loss of aconitase activity. The excess citrate was generated from glucose-derived acetyl-CoA, and global analysis of cellular lipids revealed that fatty acid biosynthesis increased markedly relative to cellular proliferation rates in Fe-S-deficient cells. We also observed intracellular lipid droplet accumulation in both acutely Fe-S-deficient cells and iron-starved cells. We conclude that deficient Fe-S biogenesis and acute iron deficiency rapidly increase cellular citrate concentrations, leading to fatty acid synthesis and cytosolic lipid droplet formation. Our findings uncover a potential cause of cellular steatosis in nonadipose tissues.
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Affiliation(s)
- Daniel R Crooks
- Urologic Oncology Branch, Center for Cancer Research, NCI, National Institutes of Health, Bethesda, Maryland 20892
| | - Nunziata Maio
- Section on Human Iron Metabolism, National Institutes of Health, Bethesda, Maryland 20892
| | - Andrew N Lane
- Center for Environmental and Systems Biochemistry, Department of Toxicology and Cancer Biology, and Markey Cancer Center, University of Kentucky, Lexington, Kentucky 40536
| | - Michal Jarnik
- Section on Cell Biology and Metabolism, Eunice Kennedy Shriver NICHD, National Institutes of Health, Bethesda, Maryland 20892
| | - Richard M Higashi
- Center for Environmental and Systems Biochemistry, Department of Toxicology and Cancer Biology, and Markey Cancer Center, University of Kentucky, Lexington, Kentucky 40536
| | - Ronald G Haller
- Department of Neurology, University of Texas Southwestern Medical Center, Dallas, Texas 75390; Veterans Affairs North Texas Medical Center, Dallas, Texas 75216; Neuromuscular Center, Institute for Exercise and Environmental Medicine, Dallas, Texas 75231
| | - Ye Yang
- Urologic Oncology Branch, Center for Cancer Research, NCI, National Institutes of Health, Bethesda, Maryland 20892
| | - Teresa W-M Fan
- Center for Environmental and Systems Biochemistry, Department of Toxicology and Cancer Biology, and Markey Cancer Center, University of Kentucky, Lexington, Kentucky 40536
| | - W Marston Linehan
- Urologic Oncology Branch, Center for Cancer Research, NCI, National Institutes of Health, Bethesda, Maryland 20892
| | - Tracey A Rouault
- Section on Human Iron Metabolism, National Institutes of Health, Bethesda, Maryland 20892.
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17
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Viegas MF, Neves RPP, Ramos MJ, Fernandes PA. Modeling of Human Fatty Acid Synthase and in Silico Docking of Acyl Carrier Protein Domain and Its Partner Catalytic Domains. J Phys Chem B 2018; 122:77-85. [DOI: 10.1021/acs.jpcb.7b09645] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Matilde F. Viegas
- REQUIMTE,
Departamento de Química
e Bioquímica, Faculdade de Ciências, Universidade do Porto, s/n, Rua do Campo
Alegre, 4169-007 Porto, Portugal
| | - Rui P. P. Neves
- REQUIMTE,
Departamento de Química
e Bioquímica, Faculdade de Ciências, Universidade do Porto, s/n, Rua do Campo
Alegre, 4169-007 Porto, Portugal
| | - Maria J. Ramos
- REQUIMTE,
Departamento de Química
e Bioquímica, Faculdade de Ciências, Universidade do Porto, s/n, Rua do Campo
Alegre, 4169-007 Porto, Portugal
| | - Pedro A. Fernandes
- REQUIMTE,
Departamento de Química
e Bioquímica, Faculdade de Ciências, Universidade do Porto, s/n, Rua do Campo
Alegre, 4169-007 Porto, Portugal
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18
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A conserved mammalian mitochondrial isoform of acetyl-CoA carboxylase ACC1 provides the malonyl-CoA essential for mitochondrial biogenesis in tandem with ACSF3. Biochem J 2017; 474:3783-3797. [PMID: 28986507 DOI: 10.1042/bcj20170416] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Revised: 09/29/2017] [Accepted: 10/03/2017] [Indexed: 01/06/2023]
Abstract
Mitochondrial fatty acid synthesis (mtFAS) is a highly conserved pathway essential for mitochondrial biogenesis. The mtFAS process is required for mitochondrial respiratory chain assembly and function, synthesis of the lipoic acid cofactor indispensable for the function of several mitochondrial enzyme complexes and essential for embryonic development in mice. Mutations in human mtFAS have been reported to lead to neurodegenerative disease. The source of malonyl-CoA for mtFAS in mammals has remained unclear. We report the identification of a conserved vertebrate mitochondrial isoform of ACC1 expressed from an ACACA transcript splicing variant. A specific knockdown (KD) of the corresponding transcript in mouse cells, or CRISPR/Cas9-mediated inactivation of the putative mitochondrial targeting sequence in human cells, leads to decreased lipoylation and mitochondrial fragmentation. Simultaneous KD of ACSF3, encoding a mitochondrial malonyl-CoA synthetase previously implicated in the mtFAS process, resulted in almost complete ablation of protein lipoylation, indicating that these enzymes have a redundant function in mtFAS. The discovery of a mitochondrial isoform of ACC1 required for lipoic acid synthesis has intriguing consequences for our understanding of mitochondrial disorders, metabolic regulation of mitochondrial biogenesis and cancer.
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19
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Angerer H, Schönborn S, Gorka J, Bahr U, Karas M, Wittig I, Heidler J, Hoffmann J, Morgner N, Zickermann V. Acyl modification and binding of mitochondrial ACP to multiprotein complexes. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2017; 1864:1913-1920. [PMID: 28802701 DOI: 10.1016/j.bbamcr.2017.08.006] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Revised: 08/03/2017] [Accepted: 08/08/2017] [Indexed: 01/06/2023]
Abstract
The mitochondrial acyl carrier protein (ACPM/NDUFAB1) is a central element of the mitochondrial fatty acid synthesis type II machinery. Originally ACPM was detected as a subunit of respiratory complex I but the reason for the association with the large enzyme complex remained elusive. Complex I from the aerobic yeast Yarrowia lipolytica comprises two different ACPMs, ACPM1 and ACPM2. They are anchored to the protein complex by LYR (leucine-tyrosine-arginine) motif containing protein (LYRM) subunits LYRM3 (NDUFB9) and LYRM6 (NDUFA6). The ACPM1-LYRM6 and ACPM2-LYRM3 modules are essential for complex I activity and assembly/stability, respectively. We show that in addition to the complex I bound fraction, ACPM1 is present as a free matrix protein and in complex with the soluble LYRM4(ISD11)/NFS1 complex implicated in Fe-S cluster biogenesis. We show that the presence of a long acyl chain bound to the phosphopantetheine cofactor is important for docking ACPMs to protein complexes and we propose that association of ACPMs and LYRMs is universally based on a new protein-protein interaction motif.
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Affiliation(s)
- Heike Angerer
- Goethe University Frankfurt, Medical School, Institute of Biochemistry II, Structural Bioenergetics Group, Max-von-Laue Str. 9, 60438 Frankfurt, Germany.
| | - Stefan Schönborn
- Goethe University Frankfurt, Institute of Pharmaceutical Chemistry, Max-von-Laue Str. 9, 60438 Frankfurt, Germany
| | - Jan Gorka
- Goethe University Frankfurt, Institute of Pharmaceutical Chemistry, Max-von-Laue Str. 9, 60438 Frankfurt, Germany
| | - Ute Bahr
- Goethe University Frankfurt, Institute of Pharmaceutical Chemistry, Max-von-Laue Str. 9, 60438 Frankfurt, Germany
| | - Michael Karas
- Goethe University Frankfurt, Institute of Pharmaceutical Chemistry, Max-von-Laue Str. 9, 60438 Frankfurt, Germany
| | - Ilka Wittig
- Functional Proteomics, SFB 815 core unit, Goethe-University Frankfurt, Medical School, Theodor-Stern-Kai 7, 60590 Frankfurt, Germany
| | - Juliana Heidler
- Functional Proteomics, SFB 815 core unit, Goethe-University Frankfurt, Medical School, Theodor-Stern-Kai 7, 60590 Frankfurt, Germany
| | - Jan Hoffmann
- Goethe University Frankfurt, Institute of Physical and Theoretical Chemistry, Max-von-Laue Str. 9, 60438 Frankfurt, Germany
| | - Nina Morgner
- Goethe University Frankfurt, Institute of Physical and Theoretical Chemistry, Max-von-Laue Str. 9, 60438 Frankfurt, Germany
| | - Volker Zickermann
- Goethe University Frankfurt, Medical School, Institute of Biochemistry II, Structural Bioenergetics Group, Max-von-Laue Str. 9, 60438 Frankfurt, Germany; Cluster of Excellence Macromolecular Complexes, Goethe University Frankfurt, Germany.
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20
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Garner WH, Garner MH. Protein Disulfide Levels and Lens Elasticity Modulation: Applications for Presbyopia. Invest Ophthalmol Vis Sci 2017; 57:2851-63. [PMID: 27233034 PMCID: PMC5995025 DOI: 10.1167/iovs.15-18413] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
PURPOSE The purpose of the experiments described here was to determine the effects of lipoic acid (LA)-dependent disulfide reduction on mouse lens elasticity, to synthesize the choline ester of LA (LACE), and to characterize the effects of topical ocular doses of LACE on mouse lens elasticity. METHODS Eight-month-old mouse lenses (C57BL/6J) were incubated for 12 hours in medium supplemented with selected levels (0-500 μM) of LA. Lens elasticity was measured using the coverslip method. After the elasticity measurements, P-SH and PSSP levels were determined in homogenates by differential alkylation before and after alkylation. Choline ester of LA was synthesized and characterized by mass spectrometry and HPLC. Eight-month-old C57BL/6J mice were treated with 2.5 μL of a formulation of 5% LACE three times per day at 8-hour intervals in the right eye (OD) for 5 weeks. After the final treatment, lenses were removed and placed in a cuvette containing buffer. Elasticity was determined with a computer-controlled instrument that provided Z-stage upward movements in 1-μm increments with concomitant force measurements with a Harvard Apparatus F10 isometric force transducer. The elasticity of lenses from 8-week-old C57BL/6J mice was determined for comparison. RESULTS Lipoic acid treatment led to a concentration-dependent decrease in lens protein disulfides concurrent with an increase in lens elasticity. The structure and purity of newly synthesized LACE was confirmed. Aqueous humor concentrations of LA were higher in eyes of mice following topical ocular treatment with LACE than in mice following topical ocular treatment with LA. The lenses of the treated eyes of the old mice were more elastic than the lenses of untreated eyes (i.e., the relative force required for similar Z displacements was higher in the lenses of untreated eyes). In most instances, the lenses of the treated eyes were even more elastic than the lenses of the 8-week-old mice. CONCLUSIONS As the elasticity of the human lens decreases with age, humans lose the ability to accommodate. The results, briefly described in this abstract, suggest a topical ocular treatment to increase lens elasticity through reduction of disulfides to restore accommodative amplitude.
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Affiliation(s)
- William H Garner
- Encore Vision, Fort Worth, Texas, United States 2Bioptics Research Partnership Consulting, Eastport, Maine, United States
| | - Margaret H Garner
- Encore Vision, Fort Worth, Texas, United States 2Bioptics Research Partnership Consulting, Eastport, Maine, United States
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Tort F, Ferrer-Cortes X, Ribes A. Differential diagnosis of lipoic acid synthesis defects. J Inherit Metab Dis 2016; 39:781-793. [PMID: 27586888 DOI: 10.1007/s10545-016-9975-4] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Revised: 08/02/2016] [Accepted: 08/04/2016] [Indexed: 01/16/2023]
Abstract
Lipoic acid (LA) is an essential cofactor required for the activity of five multienzymatic complexes that play a central role in the mitochondrial energy metabolism: four 2-oxoacid dehydrogenase complexes [pyruvate dehydrogenase (PDH), branched-chain ketoacid dehydrogenase (BCKDH), 2-ketoglutarate dehydrogenase (2-KGDH), and 2-oxoadipate dehydrogenase (2-OADH)] and the glycine cleavage system (GCS). LA is synthesized in a complex multistep process that requires appropriate function of the mitochondrial fatty acid synthesis (mtFASII) and the biogenesis of iron-sulphur (Fe-S) clusters. Defects in the biosynthesis of LA have been reported to be associated with multiple and severe defects of the mitochondrial energy metabolism. In recent years, disease-causing mutations in genes encoding for proteins involved in LA metabolism have been reported: NFU1, BOLA3, IBA57, LIAS, GLRX5, LIPT1, ISCA2, and LIPT2. These studies represented important progress in understanding the pathophysiology and molecular bases underlying these disorders. Here we review current knowledge regarding involvement of LA synthesis defects in human diseases with special emphasis on the diagnostic strategies for these disorders. The clinical and biochemical characteristics of patients with LA synthesis defects are discussed and a workup for the differential diagnosis proposed.
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Affiliation(s)
- Frederic Tort
- Secció d'Errors Congènits del Metabolisme -IBC, Servei de Bioquímica i Genètica Molecular, Hospital Clínic, IDIBAPS, CIBERER, Edifici Helios III, planta baixa, C/Mejía Lequerica s/n, 08028, Barcelona, Spain.
| | - Xènia Ferrer-Cortes
- Secció d'Errors Congènits del Metabolisme -IBC, Servei de Bioquímica i Genètica Molecular, Hospital Clínic, IDIBAPS, CIBERER, Edifici Helios III, planta baixa, C/Mejía Lequerica s/n, 08028, Barcelona, Spain
| | - Antonia Ribes
- Secció d'Errors Congènits del Metabolisme -IBC, Servei de Bioquímica i Genètica Molecular, Hospital Clínic, IDIBAPS, CIBERER, Edifici Helios III, planta baixa, C/Mejía Lequerica s/n, 08028, Barcelona, Spain
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Assembly of Lipoic Acid on Its Cognate Enzymes: an Extraordinary and Essential Biosynthetic Pathway. Microbiol Mol Biol Rev 2016; 80:429-50. [PMID: 27074917 DOI: 10.1128/mmbr.00073-15] [Citation(s) in RCA: 100] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Although the structure of lipoic acid and its role in bacterial metabolism were clear over 50 years ago, it is only in the past decade that the pathways of biosynthesis of this universally conserved cofactor have become understood. Unlike most cofactors, lipoic acid must be covalently bound to its cognate enzyme proteins (the 2-oxoacid dehydrogenases and the glycine cleavage system) in order to function in central metabolism. Indeed, the cofactor is assembled on its cognate proteins rather than being assembled and subsequently attached as in the typical pathway, like that of biotin attachment. The first lipoate biosynthetic pathway determined was that of Escherichia coli, which utilizes two enzymes to form the active lipoylated protein from a fatty acid biosynthetic intermediate. Recently, a more complex pathway requiring four proteins was discovered in Bacillus subtilis, which is probably an evolutionary relic. This pathway requires the H protein of the glycine cleavage system of single-carbon metabolism to form active (lipoyl) 2-oxoacid dehydrogenases. The bacterial pathways inform the lipoate pathways of eukaryotic organisms. Plants use the E. coli pathway, whereas mammals and fungi probably use the B. subtilis pathway. The lipoate metabolism enzymes (except those of sulfur insertion) are members of PFAM family PF03099 (the cofactor transferase family). Although these enzymes share some sequence similarity, they catalyze three markedly distinct enzyme reactions, making the usual assignment of function based on alignments prone to frequent mistaken annotations. This state of affairs has possibly clouded the interpretation of one of the disorders of human lipoate metabolism.
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Clay HB, Parl AK, Mitchell SL, Singh L, Bell LN, Murdock DG. Altering the Mitochondrial Fatty Acid Synthesis (mtFASII) Pathway Modulates Cellular Metabolic States and Bioactive Lipid Profiles as Revealed by Metabolomic Profiling. PLoS One 2016; 11:e0151171. [PMID: 26963735 PMCID: PMC4786287 DOI: 10.1371/journal.pone.0151171] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Accepted: 02/24/2016] [Indexed: 01/10/2023] Open
Abstract
Despite the presence of a cytosolic fatty acid synthesis pathway, mitochondria have retained their own means of creating fatty acids via the mitochondrial fatty acid synthesis (mtFASII) pathway. The reason for its conservation has not yet been elucidated. Therefore, to better understand the role of mtFASII in the cell, we used thin layer chromatography to characterize the contribution of the mtFASII pathway to the fatty acid composition of selected mitochondrial lipids. Next, we performed metabolomic analysis on HeLa cells in which the mtFASII pathway was either hypofunctional (through knockdown of mitochondrial acyl carrier protein, ACP) or hyperfunctional (through overexpression of mitochondrial enoyl-CoA reductase, MECR). Our results indicate that the mtFASII pathway contributes little to the fatty acid composition of mitochondrial lipid species examined. Additionally, loss of mtFASII function results in changes in biochemical pathways suggesting alterations in glucose utilization and redox state. Interestingly, levels of bioactive lipids, including lysophospholipids and sphingolipids, directly correlate with mtFASII function, indicating that mtFASII may be involved in the regulation of bioactive lipid levels. Regulation of bioactive lipid levels by mtFASII implicates the pathway as a mediator of intracellular signaling.
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Affiliation(s)
- Hayley B. Clay
- Center for Human Genetics Research, Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee, United States of America
- Neuroscience Graduate Program, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Angelika K. Parl
- Center for Human Genetics Research, Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Sabrina L. Mitchell
- Center for Human Genetics Research, Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Larry Singh
- Center for Mitochondrial and Epigenomic Medicine, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, United States of America
| | - Lauren N. Bell
- Metabolon, Incorporated, Durham, North Carolina, United States of America
| | - Deborah G. Murdock
- Center for Human Genetics Research, Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee, United States of America
- * E-mail:
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Discovery of bacterial fatty acid synthase type II inhibitors using a novel cellular bioluminescent reporter assay. Antimicrob Agents Chemother 2015; 59:5775-87. [PMID: 26169404 DOI: 10.1128/aac.00686-15] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Accepted: 07/06/2015] [Indexed: 12/11/2022] Open
Abstract
Novel, cellular, gain-of-signal, bioluminescent reporter assays for fatty acid synthesis type II (FASII) inhibitors were constructed in an efflux-deficient strain of Pseudomonas aeruginosa and based on the discovery that FASII genes in P. aeruginosa are coordinately upregulated in response to pathway disruption. A screen of 115,000 compounds identified a series of sulfonamidobenzamide (SABA) analogs, which generated strong luminescent signals in two FASII reporter strains but not in four control reporter strains designed to respond to inhibitors of pathways other than FASII. The SABA analogs selectively inhibited lipid biosynthesis in P. aeruginosa and exhibited minimal cytotoxicity to mammalian cells (50% cytotoxic concentration [CC50] ≥ 80 μM). The most potent SABA analogs had MICs of 0.5 to 7.0 μM (0.2 to 3.0 μg/ml) against an efflux-deficient Escherichia coli (ΔtolC) strain but had no detectable MIC against efflux-proficient E. coli or against P. aeruginosa (efflux deficient or proficient). Genetic, molecular genetic, and biochemical studies revealed that SABA analogs target the enzyme (AccC) catalyzing the biotin carboxylase half-reaction of the acetyl coenzyme A (acetyl-CoA) carboxylase step in the initiation phase of FASII in E. coli and P. aeruginosa. These results validate the capability and the sensitivity of this novel bioluminescent reporter screen to identify inhibitors of E. coli and P. aeruginosa FASII.
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Weber S, Salabei JK, Möller G, Kremmer E, Bhatnagar A, Adamski J, Barski OA. Aldo-keto Reductase 1B15 (AKR1B15): a mitochondrial human aldo-keto reductase with activity toward steroids and 3-keto-acyl-CoA conjugates. J Biol Chem 2015; 290:6531-45. [PMID: 25577493 DOI: 10.1074/jbc.m114.610121] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Aldo-keto reductases (AKRs) comprise a superfamily of proteins involved in the reduction and oxidation of biogenic and xenobiotic carbonyls. In humans, at least 15 AKR superfamily members have been identified so far. One of these is a newly identified gene locus, AKR1B15, which clusters on chromosome 7 with the other human AKR1B subfamily members (i.e. AKR1B1 and AKR1B10). We show that alternative splicing of the AKR1B15 gene transcript gives rise to two protein isoforms with different N termini: AKR1B15.1 is a 316-amino acid protein with 91% amino acid identity to AKR1B10; AKR1B15.2 has a prolonged N terminus and consists of 344 amino acid residues. The two gene products differ in their expression level, subcellular localization, and activity. In contrast with other AKR enzymes, which are mostly cytosolic, AKR1B15.1 co-localizes with the mitochondria. Kinetic studies show that AKR1B15.1 is predominantly a reductive enzyme that catalyzes the reduction of androgens and estrogens with high positional selectivity (17β-hydroxysteroid dehydrogenase activity) as well as 3-keto-acyl-CoA conjugates and exhibits strong cofactor selectivity toward NADP(H). In accordance with its substrate spectrum, the enzyme is expressed at the highest levels in steroid-sensitive tissues, namely placenta, testis, and adipose tissue. Placental and adipose expression could be reproduced in the BeWo and SGBS cell lines, respectively. In contrast, AKR1B15.2 localizes to the cytosol and displays no enzymatic activity with the substrates tested. Collectively, these results demonstrate the existence of a novel catalytically active AKR, which is associated with mitochondria and expressed mainly in steroid-sensitive tissues.
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Affiliation(s)
- Susanne Weber
- From the Helmholtz Zentrum Muenchen, German Research Center for Environmental Health, Institute of Experimental Genetics, Genome Analysis Center, 85764 Neuherberg, Germany
| | - Joshua K Salabei
- the Diabetes and Obesity Center, School of Medicine, University of Louisville, Louisville, Kentucky 40202
| | - Gabriele Möller
- From the Helmholtz Zentrum Muenchen, German Research Center for Environmental Health, Institute of Experimental Genetics, Genome Analysis Center, 85764 Neuherberg, Germany
| | - Elisabeth Kremmer
- the Institute of Molecular Immunology, German Research Center for Environmental Health, Helmholtz Zentrum Muenchen, 81377 Muenchen, Germany
| | - Aruni Bhatnagar
- the Diabetes and Obesity Center, School of Medicine, University of Louisville, Louisville, Kentucky 40202
| | - Jerzy Adamski
- From the Helmholtz Zentrum Muenchen, German Research Center for Environmental Health, Institute of Experimental Genetics, Genome Analysis Center, 85764 Neuherberg, Germany, the Lehrstuhl für Experimentelle Genetik, Technische Universitaet Muenchen, 85356 Freising-Weihenstephan, Germany, and the German Center for Diabetes Research, 85764 Neuherberg, Germany
| | - Oleg A Barski
- the Diabetes and Obesity Center, School of Medicine, University of Louisville, Louisville, Kentucky 40202,
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Ewald R, Hoffmann C, Florian A, Neuhaus E, Fernie AR, Bauwe H. Lipoate-Protein Ligase and Octanoyltransferase Are Essential for Protein Lipoylation in Mitochondria of Arabidopsis. PLANT PHYSIOLOGY 2014; 165:978-990. [PMID: 24872381 PMCID: PMC4081350 DOI: 10.1104/pp.114.238311] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2014] [Accepted: 05/28/2014] [Indexed: 05/18/2023]
Abstract
Prosthetic lipoyl groups are required for the function of several essential multienzyme complexes, such as pyruvate dehydrogenase (PDH), α-ketoglutarate dehydrogenase (KGDH), and the glycine cleavage system (glycine decarboxylase [GDC]). How these proteins are lipoylated has been extensively studied in prokaryotes and yeast (Saccharomyces cerevisiae), but little is known for plants. We earlier reported that mitochondrial fatty acid synthesis by ketoacyl-acyl carrier protein synthase is not vital for protein lipoylation in Arabidopsis (Arabidopsis thaliana) and does not play a significant role in roots. Here, we identify Arabidopsis lipoate-protein ligase (AtLPLA) as an essential mitochondrial enzyme that uses octanoyl-nucleoside monophosphate and possibly other donor substrates for the octanoylation of mitochondrial PDH-E2 and GDC H-protein; it shows no reactivity with bacterial and possibly plant KGDH-E2. The octanoate-activating enzyme is unknown, but we assume that it uses octanoyl moieties provided by mitochondrial β-oxidation. AtLPLA is essential for the octanoylation of PDH-E2, whereas GDC H-protein can optionally also be octanoylated by octanoyltransferase (LIP2) using octanoyl chains provided by mitochondrial ketoacyl-acyl carrier protein synthase to meet the high lipoate requirement of leaf mesophyll mitochondria. Similar to protein lipoylation in yeast, LIP2 likely also transfers octanoyl groups attached to the H-protein to KGDH-E2 but not to PDH-E2, which is exclusively octanoylated by LPLA. We suggest that LPLA and LIP2 together provide a basal protein lipoylation network to plants that is similar to that in other eukaryotes.
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Affiliation(s)
- Ralph Ewald
- Department of Plant Physiology, University of Rostock, D-18059 Rostock, Germany (R.E., H.B.);Department of Plant Physiology, University of Kaiserslautern, D-67663 Kaiserslautern, Germany (C.H., E.N.); andMax-Planck-Institut für Molekulare Pflanzenphysiologie, 14476 Potsdam-Golm, Germany (A.F., A.R.F.)
| | - Christiane Hoffmann
- Department of Plant Physiology, University of Rostock, D-18059 Rostock, Germany (R.E., H.B.);Department of Plant Physiology, University of Kaiserslautern, D-67663 Kaiserslautern, Germany (C.H., E.N.); andMax-Planck-Institut für Molekulare Pflanzenphysiologie, 14476 Potsdam-Golm, Germany (A.F., A.R.F.)
| | - Alexandra Florian
- Department of Plant Physiology, University of Rostock, D-18059 Rostock, Germany (R.E., H.B.);Department of Plant Physiology, University of Kaiserslautern, D-67663 Kaiserslautern, Germany (C.H., E.N.); andMax-Planck-Institut für Molekulare Pflanzenphysiologie, 14476 Potsdam-Golm, Germany (A.F., A.R.F.)
| | - Ekkehard Neuhaus
- Department of Plant Physiology, University of Rostock, D-18059 Rostock, Germany (R.E., H.B.);Department of Plant Physiology, University of Kaiserslautern, D-67663 Kaiserslautern, Germany (C.H., E.N.); andMax-Planck-Institut für Molekulare Pflanzenphysiologie, 14476 Potsdam-Golm, Germany (A.F., A.R.F.)
| | - Alisdair R Fernie
- Department of Plant Physiology, University of Rostock, D-18059 Rostock, Germany (R.E., H.B.);Department of Plant Physiology, University of Kaiserslautern, D-67663 Kaiserslautern, Germany (C.H., E.N.); andMax-Planck-Institut für Molekulare Pflanzenphysiologie, 14476 Potsdam-Golm, Germany (A.F., A.R.F.)
| | - Hermann Bauwe
- Department of Plant Physiology, University of Rostock, D-18059 Rostock, Germany (R.E., H.B.);Department of Plant Physiology, University of Kaiserslautern, D-67663 Kaiserslautern, Germany (C.H., E.N.); andMax-Planck-Institut für Molekulare Pflanzenphysiologie, 14476 Potsdam-Golm, Germany (A.F., A.R.F.)
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Feizi A, Bordel S. Metabolic and protein interaction sub-networks controlling the proliferation rate of cancer cells and their impact on patient survival. Sci Rep 2013; 3:3041. [PMID: 24154670 PMCID: PMC3807112 DOI: 10.1038/srep03041] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2013] [Accepted: 10/09/2013] [Indexed: 11/21/2022] Open
Abstract
Cancer cells can have a broad scope of proliferation rates. Here we aim to identify the molecular mechanisms that allow some cancer cell lines to grow up to 4 times faster than other cell lines. The correlation of gene expression profiles with the growth rate in 60 different cell lines has been analyzed using several genome-scale biological networks and new algorithms. New possible regulatory feedback loops have been suggested and the known roles of several cell cycle related transcription factors have been confirmed. Over 100 growth-correlated metabolic sub-networks have been identified, suggesting a key role of simultaneous lipid synthesis and degradation in the energy supply of the cancer cells growth. Many metabolic sub-networks involved in cell line proliferation appeared also to correlate negatively with the survival expectancy of colon cancer patients.
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Affiliation(s)
- Amir Feizi
- Department of Chemical and Biological Engineering, Kemivägen 10, Chalmers University of Technology, SE412 96 Gothenburg, Sweden
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The mitochondrial fatty acid synthesis (mtFASII) pathway is capable of mediating nuclear-mitochondrial cross talk through the PPAR system of transcriptional activation. Biochem Biophys Res Commun 2013; 441:418-24. [PMID: 24161390 DOI: 10.1016/j.bbrc.2013.10.072] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2013] [Accepted: 10/15/2013] [Indexed: 11/20/2022]
Abstract
Mammalian cells contain two fatty acid synthesis pathways, the cytosolic FASI pathway, and the mitochondrial FASII pathway. The selection behind the conservation of the mitochondrial pathway is not completely understood, given the presence of the cytosolic FAS pathway. In this study, we show through heterologous gene reporter systems and PCR-based arrays that overexpression of MECR, the last step in the mtFASII pathway, causes modulation of gene expression through the PPAR pathway. Electromobility shift assays (EMSAs) demonstrate that overexpression of MECR causes increased binding of PPARs to DNA, while cell fractionation and imaging studies show that MECR remains localized to the mitochondria. Interestingly, knock down of the mtFASII pathway lessens the effect of MECR on this transcriptional modulation. Our data are most consistent with MECR-mediated transcriptional activation through products of the mtFASII pathway, although we cannot rule out MECR acting as a coactivator. Further investigation into the physiological relevance of this communication will be necessary to better understand some of the phenotypic consequences of deficits in this pathway observed in animal models and human disease.
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Smith S, Witkowski A, Moghul A, Yoshinaga Y, Nefedov M, de Jong P, Feng D, Fong L, Tu Y, Hu Y, Young SG, Pham T, Cheung C, Katzman SM, Brand MD, Quinlan CL, Fens M, Kuypers F, Misquitta S, Griffey SM, Tran S, Gharib A, Knudsen J, Hannibal-Bach HK, Wang G, Larkin S, Thweatt J, Pasta S. Compromised mitochondrial fatty acid synthesis in transgenic mice results in defective protein lipoylation and energy disequilibrium. PLoS One 2012; 7:e47196. [PMID: 23077570 PMCID: PMC3471957 DOI: 10.1371/journal.pone.0047196] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2012] [Accepted: 09/10/2012] [Indexed: 12/19/2022] Open
Abstract
A mouse model with compromised mitochondrial fatty acid synthesis has been engineered in order to assess the role of this pathway in mitochondrial function and overall health. Reduction in the expression of mitochondrial malonyl CoA-acyl carrier protein transacylase, a key enzyme in the pathway encoded by the nuclear Mcat gene, was achieved to varying extents in all examined tissues employing tamoxifen-inducible Cre-lox technology. Although affected mice consumed more food than control animals, they failed to gain weight, were less physically active, suffered from loss of white adipose tissue, reduced muscle strength, kyphosis, alopecia, hypothermia and shortened lifespan. The Mcat-deficient phenotype is attributed primarily to reduced synthesis, in several tissues, of the octanoyl precursors required for the posttranslational lipoylation of pyruvate and α-ketoglutarate dehydrogenase complexes, resulting in diminished capacity of the citric acid cycle and disruption of energy metabolism. The presence of an alternative lipoylation pathway that utilizes exogenous free lipoate appears restricted to liver and alone is insufficient for preservation of normal energy metabolism. Thus, de novo synthesis of precursors for the protein lipoylation pathway plays a vital role in maintenance of mitochondrial function and overall vigor.
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Affiliation(s)
- Stuart Smith
- Children's Hospital Oakland Research Institute, Oakland, California, USA.
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30
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Inhibitors of fatty acid synthesis in prokaryotes and eukaryotes as anti-infective, anticancer and anti-obesity drugs. Future Med Chem 2012; 4:1113-51. [PMID: 22709254 DOI: 10.4155/fmc.12.62] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
There is a large range of diseases, such diabetes and cancer, which are connected to abnormal fatty acid metabolism in human cells. Therefore, inhibitors of human fatty acid synthase have great potential to manage or treat these diseases. In prokaryotes, fatty acid synthesis is important for signaling, as well as providing starting materials for the synthesis of phospholipids, which are required for the formation of the cell membrane. Recently, there has been renewed interest in the development of new molecules that target bacterial fatty acid synthases for the treatment of bacterial diseases. In this review, we look at the differences and similarities between fatty acid synthesis in humans and bacteria and highlight various small molecules that have been shown to inhibit either the mammalian or bacterial fatty acid synthase or both.
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31
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Huang HQ, Tang J, Zhou ST, Yi T, Peng HL, Shen GB, Xie N, Huang K, Yang T, Wu JH, Huang CH, Wei YQ, Zhao X. Orlistat, a novel potent antitumor agent for ovarian cancer: proteomic analysis of ovarian cancer cells treated with Orlistat. Int J Oncol 2012; 41:523-32. [PMID: 22581080 DOI: 10.3892/ijo.2012.1465] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2012] [Accepted: 03/19/2012] [Indexed: 11/06/2022] Open
Abstract
Orlistat is an orally administered anti-obesity drug that has shown significant antitumor activity in a variety of tumor cells. To identify the proteins involved in its antitumor activity, we employed a proteomic approach to reveal protein expression changes in the human ovarian cancer cell line SKOV3, following Orlistat treatment. Protein expression profiles were analyzed by 2-dimensional polyacrylamide gel electrophoresis (2-DE) and protein identification was performed on a MALDI-Q-TOF MS/MS instrument. More than 110 differentially expressed proteins were visualized by 2-DE and Coomassie brilliant blue staining. Furthermore, 71 proteins differentially expressed proteins were positively identified via mass spectrometry (MS)/MS analysis. In particular, PKM1/2, a key enzyme involved in tumorigenesis, was found to be significantly downregulated in SKOV3 cells following treatment with Orlistat. Moreover, PKM1/2 was proved to be downregulated in SKOV3 cells by western blot analysis after treatment with Orlistat. Taken together, using proteomic tools, we identified several differentially expressed proteins that underwent Orlistat-induced apoptosis, particularly PKM2. These changes confirmed our hypothesis that Orlistat is a potential inhibitor of ovarian cancer and can be used as a novel adjuvant antitumor agent.
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Affiliation(s)
- Hui-Qiong Huang
- Department of Gynecology and Obstetrics, Sichuan University, Chengdu, Sichuan, People's Republic of China
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32
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Abstract
The short-chain dehydrogenases/reductases (SDRs) represent a large superfamily of enzymes, most of which are NAD(H)-dependent or NADP(H)-dependent oxidoreductases. They display a wide substrate spectrum, including steroids, alcohols, sugars, aromatic compounds, and xenobiotics. On the basis of characteristic sequence motifs, the SDRs are subdivided into two main (classical and extended) and three smaller (divergent, intermediate, and complex) families. Despite low residue identities in pairwise comparisons, the three-dimensional structure among the SDRs is conserved and shows a typical Rossmann fold. Here, we used a bioinformatics approach to determine whether and which SDRs are present in cyanobacteria, microorganisms that played an important role in our ecosystem as the first oxygen producers. Cyanobacterial SDRs could indeed be identified, and were clustered according to the SDR classification system. Furthermore, because of the early availability of its genome sequence and the easy application of transformation methods, Synechocystis sp. PCC 6803, one of the most important cyanobacterial strains, was chosen as the model organism for this phylum. Synechocystis sp. SDRs were further analysed with bioinformatics tools, such as hidden Markov models (HMMs). It became evident that several cyanobacterial SDRs show remarkable sequence identities with SDRs in other organisms. These so-called 'homologous' proteins exist in plants, model organisms such as Drosophila melanogaster and Caenorhabditis elegans, and even in humans. As sequence identities of up to 60% were found between Synechocystis and humans, it was concluded that SDRs seemed to have been well conserved during evolution, even after dramatic terrestrial changes such as the conversion of the early reducing atmosphere to an oxidizing one by cyanobacteria.
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Affiliation(s)
- Anneke Kramm
- University Medical School Schleswig-Holstein Campus Kiel, Institute of Toxicology and Pharmacology for Natural Scientists, Schleswig-Holstein, Germany
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33
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Jensen-Urstad APL, Semenkovich CF. Fatty acid synthase and liver triglyceride metabolism: housekeeper or messenger? Biochim Biophys Acta Mol Cell Biol Lipids 2011; 1821:747-53. [PMID: 22009142 DOI: 10.1016/j.bbalip.2011.09.017] [Citation(s) in RCA: 243] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2011] [Revised: 09/26/2011] [Accepted: 09/27/2011] [Indexed: 01/14/2023]
Abstract
Fatty acid synthase (FAS) catalyzes the de novo synthesis of fatty acids. In the liver, FAS has long been categorized as a housekeeping protein, producing fat for storage of energy when nutrients are present in excess. Most previous studies of FAS regulation have focused on the control of gene expression. However, recent findings suggest that hepatic FAS may also be involved in signaling processes that include activation of peroxisome proliferator-activated receptor α (PPARα). Moreover, reports of rapid alterations in FAS activity as well as findings of post-translational modifications of the FAS protein support the notion that dynamic events in addition to transcription impact FAS regulation. These results indicate that FAS enzyme activity can impact liver physiology through signaling as well as energy storage and that its regulation may be complex. This article is part of a Special Issue entitled Triglyceride Metabolism and Disease.
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Affiliation(s)
- Anne P L Jensen-Urstad
- Division of Endocrinology, Metabolism & Lipid Research, Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
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Witkowski A, Thweatt J, Smith S. Mammalian ACSF3 protein is a malonyl-CoA synthetase that supplies the chain extender units for mitochondrial fatty acid synthesis. J Biol Chem 2011; 286:33729-36. [PMID: 21846720 PMCID: PMC3190830 DOI: 10.1074/jbc.m111.291591] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2011] [Indexed: 11/06/2022] Open
Abstract
The objective of this study was to identify a source of intramitochondrial malonyl-CoA that could be used for de novo fatty acid synthesis in mammalian mitochondria. Because mammalian mitochondria lack an acetyl-CoA carboxylase capable of generating malonyl-CoA inside mitochondria, the possibility that malonate could act as a precursor was investigated. Although malonyl-CoA synthetases have not been identified previously in animals, interrogation of animal protein sequence databases identified candidates that exhibited sequence similarity to known prokaryotic forms. The human candidate protein ACSF3, which has a predicted N-terminal mitochondrial targeting sequence, was cloned, expressed, and characterized as a 65-kDa acyl-CoA synthetase with extremely high specificity for malonate and methylmalonate. An arginine residue implicated in malonate binding by prokaryotic malonyl-CoA synthetases was found to be positionally conserved in animal ACSF3 enzymes and essential for activity. Subcellular fractionation experiments with HEK293T cells confirmed that human ACSF3 is located exclusively in mitochondria, and RNA interference experiments verified that this enzyme is responsible for most, if not all, of the malonyl-CoA synthetase activity in the mitochondria of these cells. In conclusion, unlike fungi, which have an intramitochondrial acetyl-CoA carboxylase, animals require an alternative source of mitochondrial malonyl-CoA; the mitochondrial ACSF3 enzyme is capable of filling this role by utilizing free malonic acid as substrate.
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Affiliation(s)
- Andrzej Witkowski
- From the Children's Hospital Oakland Research Institute, Oakland, California 94609
| | - Jennifer Thweatt
- From the Children's Hospital Oakland Research Institute, Oakland, California 94609
| | - Stuart Smith
- From the Children's Hospital Oakland Research Institute, Oakland, California 94609
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35
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Lodhi IJ, Wei X, Semenkovich CF. Lipoexpediency: de novo lipogenesis as a metabolic signal transmitter. Trends Endocrinol Metab 2011; 22:1-8. [PMID: 20889351 PMCID: PMC3011046 DOI: 10.1016/j.tem.2010.09.002] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2010] [Revised: 09/03/2010] [Accepted: 09/07/2010] [Indexed: 02/06/2023]
Abstract
De novo lipogenesis, the production of fats from simple precursors, is often dismissed as irrelevant to the pathobiology of obesity caused by positive energy balance due to typical high fat diets. However, emerging data implicate de novo lipogenesis in the generation of metabolic signals that alter disease risk. Exploiting this signaling pathway represents lipoexpediency. Lipoexpediency is the concept of directing fats toward benefit even in the setting of lipid overload, and represents a strategy to complement efforts aimed at improving energy balance. Optimizing lipid signals initiated by key lipogenic enzymes such as fatty acid synthase might limit morbidity in people who are unlikely to abandon the lifestyle of the sedentary gourmand.
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Affiliation(s)
- Irfan J Lodhi
- Department of Medicine, Washington University School of Medicine, Campus Box 8127, 660 South Euclid Avenue, St. Louis, MO 63110, USA
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36
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Senning EN, Marcus AH. Subcellular dynamics and protein conformation fluctuations measured by Fourier imaging correlation spectroscopy. Annu Rev Phys Chem 2010; 61:111-28. [PMID: 20055672 DOI: 10.1146/annurev.physchem.012809.103500] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Novel high signal-to-noise spectroscopic experiments that probe the dynamics of microscopic objects have the potential to reveal complex intracellular biochemical mechanisms, or the slow relaxations of soft matter systems. This article reviews the implementation of Fourier imaging correlation spectroscopy (FICS), a phase-selective approach to fluorescence fluctuation spectroscopy that employs a unique route to elevate signal levels while acquiring detailed information about molecular coordinate trajectories. The review demonstrates the broad applicability of FICS by discussing two recent studies. The dynamics of Saccharomyces cerevisiae yeast mitochondria are characterized with FICS and provide detailed information about the influence of specific cytoskeletal elements on the movement of this organelle. In another set of experiments, polarization-modulated FICS captures conformational dynamics and molecular translational dynamics of the fluorescent protein DsRed, and analyses by four-point correlation and joint distribution functions of the corresponding data reveal statistically meaningful pathways of DsRed switching between different optical conformations.
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Affiliation(s)
- Eric N Senning
- Department of Chemistry, Oregon Center for Optics, Institute of Molecular Biology, University of Oregon, Eugene, Oregon 97403, USA
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37
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Huang HJ, Chen CY, Chen HY, Tsai FJ, Chen CYC. Computational screening and QSAR analysis for design of AMP-activated protein kinase agonist. J Taiwan Inst Chem Eng 2010. [DOI: 10.1016/j.jtice.2009.09.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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38
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Hiltunen JK, Autio KJ, Schonauer MS, Kursu VAS, Dieckmann CL, Kastaniotis AJ. Mitochondrial fatty acid synthesis and respiration. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2010; 1797:1195-202. [PMID: 20226757 DOI: 10.1016/j.bbabio.2010.03.006] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2009] [Revised: 02/24/2010] [Accepted: 03/03/2010] [Indexed: 10/19/2022]
Abstract
Recent studies have revealed that mitochondria are able to synthesize fatty acids in a malonyl-CoA/acyl carrier protein (ACP)-dependent manner. This pathway resembles bacterial fatty acid synthesis (FAS) type II, which uses discrete, nuclearly encoded proteins. Experimental evidence, obtained mainly through using yeast as a model system, indicates that this pathway is essential for mitochondrial respiratory function. Curiously, the deficiency in mitochondrial FAS cannot be complemented by inclusion of fatty acids in the culture medium or by products of the cytosolic FAS complex. Defects in mitochondrial FAS in yeast result in the inability to grow on nonfermentable carbon sources, the loss of mitochondrial cytochromes a/a3 and b, mitochondrial RNA processing defects, and loss of cellular lipoic acid. Eukaryotic FAS II generates octanoyl-ACP, a substrate for mitochondrial lipoic acid synthase. Endogenous lipoic acid synthesis challenges the hypothesis that lipoic acid can be provided as an exogenously supplied vitamin. Purified eukaryotic FAS II enzymes are catalytically active in vitro using substrates with an acyl chain length of up to 16 carbon atoms. However, with the exception of 3-hydroxymyristoyl-ACP, a component of respiratory complex I in higher eukaryotes, the fate of long-chain fatty acids synthesized by the mitochondrial FAS pathway remains an enigma. The linkage of FAS II genes to published animal models for human disease supports the hypothesis that mitochondrial FAS dysfunction leads to the development of disorders in mammals.
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Affiliation(s)
- J Kalervo Hiltunen
- Department of Biochemistry and Biocenter Oulu, University of Oulu, PO Box 3000, FI-90014 Oulu, Finland.
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Bioenergetic pathways in tumor mitochondria as targets for cancer therapy and the importance of the ROS-induced apoptotic trigger. Mol Aspects Med 2010; 31:29-59. [DOI: 10.1016/j.mam.2009.12.006] [Citation(s) in RCA: 125] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2009] [Accepted: 12/11/2009] [Indexed: 12/22/2022]
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40
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Hiltunen JK, Chen Z, Haapalainen AM, Wierenga RK, Kastaniotis AJ. Mitochondrial fatty acid synthesis – An adopted set of enzymes making a pathway of major importance for the cellular metabolism. Prog Lipid Res 2010; 49:27-45. [DOI: 10.1016/j.plipres.2009.08.001] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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41
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Rosca MG, Lemieux H, Hoppel CL. Mitochondria in the elderly: Is acetylcarnitine a rejuvenator? Adv Drug Deliv Rev 2009; 61:1332-1342. [PMID: 19720100 DOI: 10.1016/j.addr.2009.06.009] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2009] [Accepted: 06/01/2009] [Indexed: 12/21/2022]
Abstract
Endogenous acetylcarnitine is an indicator of acetyl-CoA synthesized by multiple metabolic pathways involving carbohydrates, amino acids, fatty acids, sterols, and ketone bodies, and utilized mainly by the tricarboxylic acid cycle. Acetylcarnitine supplementation has beneficial effects in elderly animals and humans, including restoration of mitochondrial content and function. These effects appear to be dose-dependent and occur even after short-term therapy. In order to set the stage for understanding the mechanism of action of acetylcarnitine, we review the metabolism and role of this compound. We suggest that acetylation of mitochondrial proteins leads to a specific increase in mitochondrial gene expression and mitochondrial protein synthesis. In the aged rat heart, this effect is translated to increased cytochrome b content, restoration of complex III activity, and oxidative phosphorylation, resulting in amelioration of the age-related mitochondrial defect.
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Affiliation(s)
- Mariana G Rosca
- Center for Mitochondrial Diseases and Departments of Medicine and Pharmacology, Case Western Reserve University, Cleveland, Ohio
| | - Hélène Lemieux
- Center for Mitochondrial Diseases and Departments of Medicine and Pharmacology, Case Western Reserve University, Cleveland, Ohio
| | - Charles L Hoppel
- Center for Mitochondrial Diseases and Departments of Medicine and Pharmacology, Case Western Reserve University, Cleveland, Ohio
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Bunkoczi G, Misquitta S, Wu X, Lee WH, Rojkova A, Kochan G, Kavanagh KL, Oppermann U, Smith S. Structural basis for different specificities of acyltransferases associated with the human cytosolic and mitochondrial fatty acid synthases. ACTA ACUST UNITED AC 2009; 16:667-75. [PMID: 19549604 DOI: 10.1016/j.chembiol.2009.04.011] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2008] [Revised: 03/26/2009] [Accepted: 04/14/2009] [Indexed: 12/28/2022]
Abstract
Animals employ two systems for the de novo biosynthesis of fatty acids: a megasynthase complex in the cytosol (type I) that produces mainly palmitate, and an ensemble of freestanding enzymes in the mitochondria (type II) that produces mainly octanoyl moieties. The acyltransferases responsible for initiation of fatty acid biosynthesis in the two compartments are distinguished by their different substrate specificities: the type I enzyme transfers both the acetyl primer and the malonyl chain extender, whereas the type II enzyme is responsible for translocation of only the malonyl substrate. Crystal structures for the type I and II enzymes, supported by in silico substrate docking studies and mutagenesis experiments that alter their respective specificities, reveal that, although the two enzymes adopt a similar overall fold, subtle differences at their catalytic centers account for their different specificities.
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Affiliation(s)
- Gabor Bunkoczi
- Structural Genomics Consortium, University of Oxford, Oxford OX3 7LD, UK
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43
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Chen Z, Kastaniotis AJ, Miinalainen IJ, Rajaram V, Wierenga RK, Hiltunen JK. 17beta-hydroxysteroid dehydrogenase type 8 and carbonyl reductase type 4 assemble as a ketoacyl reductase of human mitochondrial FAS. FASEB J 2009; 23:3682-91. [PMID: 19571038 DOI: 10.1096/fj.09-133587] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Mitochondrial fatty acid synthesis (FAS) generates the octanoyl-group that is required for the synthesis of lipoic acid and is linked to mitochondrial RNA metabolism. All of the human enzymes involved in mitochondrial FAS have been characterized except for beta-ketoacyl thioester reductase (HsKAR), which catalyzes the second step in the pathway. We report here the unexpected finding that a heterotetramer composed of human 17beta-hydroxysteroid dehydrogenase type 8 (Hs17beta-HSD8) and human carbonyl reductase type 4 (HsCBR4) forms the long-sought HsKAR. Both proteins share sequence similarities to the yeast 3-oxoacyl-(acyl carrier protein) reductase (Oar1p) and the bacterial FabG, although HsKAR is NADH dependent, whereas FabG and Oar1p are NADPH dependent. Hs17beta-HSD8 and HsCBR4 show a strong genetic interaction in vivo in yeast, where, only if they are expressed together, they rescue the respiratory deficiency and restore the lipoic acid content of oar1Delta cells. Moreover, these two proteins display a stable physical interaction and form an active heterotetramer. Both Hs17beta-HSD8 and HsCBR4 are targeted to mitochondria in vivo in cultured HeLa cells. Notably, 17beta-HSD8 was previously classified as a steroid-metabolizing enzyme, but our data suggest that 17beta-HSD8 is primarily involved in mitochondrial FAS.
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Affiliation(s)
- Zhijun Chen
- Biocenter Oulu, and Department of Biochemistry, P. O. Box 3000, FI-90014 University of Oulu, Finland
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Chen Z, Leskinen H, Liimatta E, Sormunen RT, Miinalainen IJ, Hassinen IE, Hiltunen JK. Myocardial overexpression of Mecr, a gene of mitochondrial FAS II leads to cardiac dysfunction in mouse. PLoS One 2009; 4:e5589. [PMID: 19440339 PMCID: PMC2680037 DOI: 10.1371/journal.pone.0005589] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2008] [Accepted: 04/22/2009] [Indexed: 11/18/2022] Open
Abstract
It has been recently recognized that mammalian mitochondria contain most, if not all, of the components of fatty acid synthesis type II (FAS II). Among the components identified is 2-enoyl thioester reductase/mitochondrial enoyl-CoA reductase (Etr1/Mecr), which catalyzes the NADPH-dependent reduction of trans-2-enoyl thioesters, generating saturated acyl-groups. Although the FAS type II pathway is highly conserved, its physiological role in fatty acid synthesis, which apparently occurs simultaneously with breakdown of fatty acids in the same subcellular compartment in mammals, has remained an enigma. To study the in vivo function of the mitochondrial FAS in mammals, with special reference to Mecr, we generated mice overexpressing Mecr under control of the mouse metallothionein-1 promoter. These Mecr transgenic mice developed cardiac abnormalities as demonstrated by echocardiography in vivo, heart perfusion ex vivo, and electron microscopy in situ. Moreover, the Mecr transgenic mice showed decreased performance in endurance exercise testing. Our results showed a ventricular dilatation behind impaired heart function upon Mecr overexpression, concurrent with appearance of dysmorphic mitochondria. Furthermore, the data suggested that inappropriate expression of genes of FAS II can result in the development of hereditary cardiomyopathy.
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Affiliation(s)
- Zhijun Chen
- Biocenter Oulu and Department of Biochemistry, University of Oulu, Oulu, Finland
| | - Hanna Leskinen
- Biocenter Oulu and Department of Pharmacology and Toxicology, University of Oulu, Oulu, Finland
| | - Erkki Liimatta
- Department of Medical Biochemistry and Molecular Biology, University of Oulu, Oulu, Finland
| | - Raija T. Sormunen
- Biocenter Oulu and Department of Pathology, University of Oulu, Oulu, Finland
| | - Ilkka J. Miinalainen
- Biocenter Oulu and Department of Biochemistry, University of Oulu, Oulu, Finland
| | - Ilmo E. Hassinen
- Department of Medical Biochemistry and Molecular Biology, University of Oulu, Oulu, Finland
| | - J. Kalervo Hiltunen
- Biocenter Oulu and Department of Biochemistry, University of Oulu, Oulu, Finland
- * E-mail:
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Günther S, Matuschewski K, Müller S. Knockout studies reveal an important role of Plasmodium lipoic acid protein ligase A1 for asexual blood stage parasite survival. PLoS One 2009; 4:e5510. [PMID: 19434237 PMCID: PMC2677453 DOI: 10.1371/journal.pone.0005510] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2008] [Accepted: 04/08/2009] [Indexed: 01/12/2023] Open
Abstract
Lipoic acid (LA) is a dithiol-containing cofactor that is essential for the function of α-keto acid dehydrogenase complexes. LA acts as a reversible acyl group acceptor and ‘swinging arm’ during acyl-coenzyme A formation. The cofactor is post-translationally attached to the acyl-transferase subunits of the multienzyme complexes through the action of octanoyl (lipoyl): N-octanoyl (lipoyl) transferase (LipB) or lipoic acid protein ligases (LplA). Remarkably, apicomplexan parasites possess LA biosynthesis as well as scavenging pathways and the two pathways are distributed between mitochondrion and a vestigial organelle, the apicoplast. The apicoplast-specific LipB is dispensable for parasite growth due to functional redundancy of the parasite's lipoic acid/octanoic acid ligases/transferases. In this study, we show that LplA1 plays a pivotal role during the development of the erythrocytic stages of the malaria parasite. Gene disruptions in the human malaria parasite P. falciparum consistently were unsuccessful while in the rodent malaria model parasite P. berghei the LplA1 gene locus was targeted by knock-in and knockout constructs. However, the LplA1(−) mutant could not be cloned suggesting a critical role of LplA1 for asexual parasite growth in vitro and in vivo. These experimental genetics data suggest that lipoylation during expansion in red blood cells largely occurs through salvage from the host erythrocytes and subsequent ligation of LA to the target proteins of the malaria parasite.
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Affiliation(s)
- Svenja Günther
- Division of Infection & Immunity and Wellcome Centre for Parasitology, Faculty of Biomedical and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Kai Matuschewski
- Department of Parasitology, Heidelberg University, School of Medicine, Im Neuenheimer Feld, Heidelberg, Germany
| | - Sylke Müller
- Division of Infection & Immunity and Wellcome Centre for Parasitology, Faculty of Biomedical and Life Sciences, University of Glasgow, Glasgow, United Kingdom
- * E-mail:
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Feng D, Witkowski A, Smith S. Down-regulation of mitochondrial acyl carrier protein in mammalian cells compromises protein lipoylation and respiratory complex I and results in cell death. J Biol Chem 2009; 284:11436-45. [PMID: 19221180 DOI: 10.1074/jbc.m806991200] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The objective of this study was to evaluate the physiological importance of the mitochondrial fatty acid synthesis pathway in mammalian cells using the RNA interference strategy. Transfection of HEK293T cells with small interfering RNAs targeting the acyl carrier protein (ACP) component reduced ACP mRNA and protein levels by >85% within 24 h. The earliest phenotypic changes observed were a marked decrease in the proportion of post-translationally lipoylated mitochondrial proteins recognized by anti-lipoate antibodies and a reduction in their catalytic activity, and a slowing of the cell growth rate. Later effects observed included a reduction in the specific activity of respiratory complex I, lowered mitochondrial membrane potential, the development of cytoplasmic membrane blebs containing high levels of reactive oxygen species and ultimately, cell death. Supplementation of the culture medium with lipoic acid offered some protection against oxidative damage but did not reverse the protein lipoylation defect. These observations are consistent with a dual role for ACP in mammalian mitochondrial function. First, as a key component of the mitochondrial fatty acid biosynthetic pathway, ACP plays an essential role in providing the octanoyl-ACP precursor required for the protein lipoylation pathway. Second, as one of the subunits of complex I, ACP is required for the efficient functioning of the electron transport chain and maintenance of normal mitochondrial membrane potential.
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Affiliation(s)
- Dejiang Feng
- Children's Hospital Oakland Research Institute, Oakland, California 94609, USA
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Menendez JA, Vazquez-Martin A, Ortega FJ, Fernandez-Real JM. Fatty acid synthase: association with insulin resistance, type 2 diabetes, and cancer. Clin Chem 2009; 55:425-38. [PMID: 19181734 DOI: 10.1373/clinchem.2008.115352] [Citation(s) in RCA: 137] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
BACKGROUND An emerging paradigm supports the notion that deregulation of fatty acid synthase (FASN)-catalyzed de novo FA biogenesis could play a central role in the pathogenesis of metabolic diseases sharing the hallmark of insulin-resistance. CONTENT We reviewed pharmacological and genetic alterations of FASN activity that have been shown to significantly influence energy expenditure rates, fat mass, insulin sensitivity, and cancer risk. This new paradigm proposes that insulin-resistant conditions such as obesity, type 2 diabetes, and cancer arise from a common FASN-driven "lipogenic state". An important question then is whether the development or the progression of insulin-related metabolic disorders can be prevented or reversed by the modulation of FASN status. If we accept the paradigm of FASN dysfunction as a previously unrecognized link between insulin resistance, type 2 diabetes, and cancer, the use of insulin sensitizers in parallel with forthcoming FASN inhibitors should be a valuable therapeutic approach that, in association with lifestyle interventions, would concurrently improve energy-flux status, ameliorate insulin sensitivity, and alleviate the risk of lipogenic carcinomas. CONCLUSIONS Although the picture is currently incomplete and researchers in the field have plenty of work ahead, the latest clinical and experimental evidence that we discuss illuminates a functional and drug-modifiable link that connects FASN-driven endogenous FA biosynthesis, insulin action, and glucose homeostasis in the natural history of insulin-resistant pathologies.
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Affiliation(s)
- Javier A Menendez
- Catalan Institute of Oncology, Girona Biomedical Research Institute, Hospital Universitari de Girona Josep Trueta, Girona, Catalonia, Spain.
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Oliveras-Ferraros C, Vazquez-Martin A, Fernández-Real JM, Menendez JA. AMPK-sensed cellular energy state regulates the release of extracellular Fatty Acid Synthase. Biochem Biophys Res Commun 2008; 378:488-93. [PMID: 19032940 DOI: 10.1016/j.bbrc.2008.11.067] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2008] [Accepted: 11/14/2008] [Indexed: 10/21/2022]
Abstract
Fatty Acid Synthase (FASN), a 250-kDa cytosolic multi-enzyme catalyzing eukaryotic de novo FA biogenesis, unexpectedly localizes in cancer cell culture supernatants and in the blood of cancer patients. High levels of "extracellular FASN" have recently been found in supernatants from Hepatitis C Virus-infected liver cells. The ultimate mechanism regulating FASN release, however, remained completely undefined. When the AMPK-activating drug AICAR was used to simulate an elevated AMP/ATP ratio in breast cancer cells, ELISA-based analyses revealed that extracellular FASN dramatically augmented in a dose- and time-dependent manner. Immunoblotting procedures using a battery of anti-FASN antibodies further confirmed that, in response to AMPK activation, FASN protein is depleted from the cytosol to accumulate as different FASN isoforms in the extracellular milieu. siRNA-induced blockade of AMPK expression largely attenuated AICAR-promoted FASN release. FASN release might represent a previously unrecognized mechanism through which AMPK monitor and restores cellular energy state in response to increasing AMP/ATP ratios.
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Affiliation(s)
- Cristina Oliveras-Ferraros
- Catalan Institute of Oncology, Girona (ICO-Girona), Hospital de Girona "Dr. Josep Trueta", Ctra. França s/n, E-17007 Girona, Catalonia, Spain
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Hiltunen JK, Schonauer MS, Autio KJ, Mittelmeier TM, Kastaniotis AJ, Dieckmann CL. Mitochondrial fatty acid synthesis type II: more than just fatty acids. J Biol Chem 2008; 284:9011-5. [PMID: 19028688 DOI: 10.1074/jbc.r800068200] [Citation(s) in RCA: 127] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Eukaryotes harbor a highly conserved mitochondrial pathway for fatty acid synthesis (FAS), which is completely independent of the eukaryotic cytosolic FAS apparatus. The activities of the mitochondrial FAS system are catalyzed by soluble enzymes, and the pathway thus resembles its prokaryotic counterparts. Except for octanoic acid, which is the direct precursor for lipoic acid synthesis, other end products and functions of the mitochondrial FAS pathway are still largely enigmatic. In addition to low cellular levels of lipoic acid, disruption of genes encoding mitochondrial FAS enzymes in yeast results in a respiratory-deficient phenotype and small rudimentary mitochondria. Recently, two distinct links between mitochondrial FAS and RNA processing have been discovered in vertebrates and yeast, respectively. In vertebrates, the mitochondrial 3-hydroxyacyl-acyl carrier protein dehydratase and the RPP14 subunit of RNase P are encoded by the same bicistronic transcript in an evolutionarily conserved arrangement that is unusual for eukaryotes. In yeast, defects in mitochondrial FAS result in inefficient RNase P cleavage in the organelle. The intersection of mitochondrial FAS and RNA metabolism in both systems provides a novel mechanism for the coordination of intermediary metabolism in eukaryotic cells.
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Affiliation(s)
- J Kalervo Hiltunen
- Department of Biochemistry and Biocenter Oulu, University of Oulu, FI-90014 Oulu, Finland.
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