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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Azevedo RDSD, Falcão KVG, Almeida SMVD, Araújo MC, Silva-Filho RC, Souza Maia MBD, Amaral IPGD, Leite ACR, de Souza Bezerra R. The tissue-specific nature of physiological zebrafish mitochondrial bioenergetics. Mitochondrion 2024; 77:101901. [PMID: 38777222 DOI: 10.1016/j.mito.2024.101901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Revised: 04/27/2024] [Accepted: 05/15/2024] [Indexed: 05/25/2024]
Abstract
Zebrafish are a powerful tool to study a myriad of experimental conditions, including mitochondrial bioenergetics. Considering that mitochondria are different in many aspects depending on the tissue evaluated, in the zebrafish model there is still a lack of this investigation. Especially for juvenile zebrafish. In the present study, we examined whether different tissues from zebrafish juveniles show mitochondrial density- and tissue-specificity comparing brain, liver, heart, and skeletal muscle (SM). The liver and brain complex IV showed the highest O2 consumption of all ETC in all tissues (10x when compared to other respiratory complexes). The liver showed a higher potential for ROS generation. In this way, the brain and liver showed more susceptibility to O2- generation when compared to other tissues. Regarding Ca2+ transport, the brain showed greater capacity for Ca2+ uptake and the liver presented low Ca2+ uptake capacity. The liver and brain were more susceptible to producing NO. The enzymes SOD and Catalase showed high activity in the brain, whereas GPx showed higher activity in the liver and CS in the SM. TEM reveals, as expected, a physiological diverse mitochondrial morphology. The essential differences between zebrafish tissues investigated probably reflect how the mitochondria play a diverse role in systemic homeostasis. This feature may not be limited to normal metabolic functions but also to stress conditions. In summary, mitochondrial bioenergetics in zebrafish juvenile permeabilized tissues showed a tissue-specificity and a useful tool to investigate conditions of redox system imbalance, mainly in the liver and brain.
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Affiliation(s)
- Rafael David Souto de Azevedo
- Laboratório de Biologia Celular e Molecular, Universidade de Pernambuco - UPE, Campus Garanhuns, Garanhuns, PE, Brazil.
| | - Kivia Vanessa Gomes Falcão
- Departamento de Bioquímica, Universidade Federal de Pernambuco, Cidade Universitária, Recife, PE, Brazil
| | | | - Marlyete Chagas Araújo
- Departamento de Bioquímica, Universidade Federal de Pernambuco, Cidade Universitária, Recife, PE, Brazil
| | | | | | | | | | - Ranilson de Souza Bezerra
- Departamento de Bioquímica, Universidade Federal de Pernambuco, Cidade Universitária, Recife, PE, Brazil
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3
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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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4
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Mohaupt P, Roucou X, Delaby C, Vialaret J, Lehmann S, Hirtz C. The alternative proteome in neurobiology. Front Cell Neurosci 2022; 16:1019680. [PMID: 36467612 PMCID: PMC9712206 DOI: 10.3389/fncel.2022.1019680] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Accepted: 11/02/2022] [Indexed: 10/13/2023] Open
Abstract
Translation involves the biosynthesis of a protein sequence following the decoding of the genetic information embedded in a messenger RNA (mRNA). Typically, the eukaryotic mRNA was considered to be inherently monocistronic, but this paradigm is not in agreement with the translational landscape of cells, tissues, and organs. Recent ribosome sequencing (Ribo-seq) and proteomics studies show that, in addition to currently annotated reference proteins (RefProt), other proteins termed alternative proteins (AltProts), and microproteins are encoded in regions of mRNAs thought to be untranslated or in transcripts annotated as non-coding. This experimental evidence expands the repertoire of functional proteins within a cell and potentially provides important information on biological processes. This review explores the hitherto overlooked alternative proteome in neurobiology and considers the role of AltProts in pathological and healthy neuromolecular processes.
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Affiliation(s)
- Pablo Mohaupt
- LBPC-PPC, Université de Montpellier, IRMB CHU de Montpellier, INM INSERM, Montpellier, France
| | - Xavier Roucou
- Department of Biochemistry and Functional Genomics, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Constance Delaby
- LBPC-PPC, Université de Montpellier, IRMB CHU de Montpellier, INM INSERM, Montpellier, France
| | - Jérôme Vialaret
- LBPC-PPC, Université de Montpellier, IRMB CHU de Montpellier, INM INSERM, Montpellier, France
| | - Sylvain Lehmann
- LBPC-PPC, Université de Montpellier, IRMB CHU de Montpellier, INM INSERM, Montpellier, France
| | - Christophe Hirtz
- LBPC-PPC, Université de Montpellier, IRMB CHU de Montpellier, INM INSERM, Montpellier, France
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5
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Altered Metabolic Flexibility in Inherited Metabolic Diseases of Mitochondrial Fatty Acid Metabolism. Int J Mol Sci 2021; 22:ijms22073799. [PMID: 33917608 PMCID: PMC8038842 DOI: 10.3390/ijms22073799] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 04/03/2021] [Accepted: 04/05/2021] [Indexed: 12/14/2022] Open
Abstract
In general, metabolic flexibility refers to an organism's capacity to adapt to metabolic changes due to differing energy demands. The aim of this work is to summarize and discuss recent findings regarding variables that modulate energy regulation in two different pathways of mitochondrial fatty metabolism: β-oxidation and fatty acid biosynthesis. We focus specifically on two diseases: very long-chain acyl-CoA dehydrogenase deficiency (VLCADD) and malonyl-CoA synthetase deficiency (acyl-CoA synthetase family member 3 (ACSF3)) deficiency, which are both characterized by alterations in metabolic flexibility. On the one hand, in a mouse model of VLCAD-deficient (VLCAD-/-) mice, the white skeletal muscle undergoes metabolic and morphologic transdifferentiation towards glycolytic muscle fiber types via the up-regulation of mitochondrial fatty acid biosynthesis (mtFAS). On the other hand, in ACSF3-deficient patients, fibroblasts show impaired mitochondrial respiration, reduced lipoylation, and reduced glycolytic flux, which are compensated for by an increased β-oxidation rate and the use of anaplerotic amino acids to address the energy needs. Here, we discuss a possible co-regulation by mtFAS and β-oxidation in the maintenance of energy homeostasis.
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Zeng M, Xu J, Zhang Z, Zou X, Wang X, Cao K, Lv W, Cui Y, Long J, Feng Z, Liu J. Htd2 deficiency-associated suppression of α-lipoic acid production provokes mitochondrial dysfunction and insulin resistance in adipocytes. Redox Biol 2021; 41:101948. [PMID: 33774475 PMCID: PMC8027779 DOI: 10.1016/j.redox.2021.101948] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Revised: 03/03/2021] [Accepted: 03/15/2021] [Indexed: 12/11/2022] Open
Abstract
Mitochondria harbor a unique fatty acid synthesis pathway (mtFAS) with mysterious functions gaining increasing interest, while its involvement in metabolic regulation is essentially unknown. Here we show that 3-Hydroxyacyl-ACP dehydratase (HTD2), a key enzyme in mtFAS pathway was primarily downregulated in adipocytes of mice under metabolic disorders, accompanied by decreased de novo production of lipoic acid, which is the byproduct of mtFAS pathway. Knockdown of Htd2 in 3T3-L1 preadipocytes or differentiated 3T3-L1 mature adipocytes impaired mitochondrial function via suppression of complex I activity, resulting in enhanced oxidative stress and impaired insulin sensitivity, which were all attenuated by supplement of lipoic acid. Moreover, lipidomic study revealed limited lipid alterations in mtFAS deficient cells which primarily presenting accumulation of triglycerides, attributed to mitochondrial dysfunction. Collectively, the present study highlighted the pivotal role of mtFAS pathway in regulating mitochondrial function and adipocytes insulin sensitivity, demonstrating supportive evidence for lipoic acid being potential effective nutrient for improving insulin resistance and related metabolic disorders. 3-Hydroxyacyl-ACP dehydratase is decreased in adipocytes under diabetic condition. Deficient of 3-Hydroxyacyl-ACP dehydratase (HTD2) triggers mitochondrial dysfunction. Deficient of HTD2 promotes insulin resistance in adipocytes. Supplement of lipoic acid ameliorates deleterious effects of HTD2 deficiency.
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Affiliation(s)
- Mengqi Zeng
- Center for Mitochondrial Biology and Medicine, The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi, 710049, China
| | - Jie Xu
- Center for Mitochondrial Biology and Medicine, The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi, 710049, China
| | - Zhengyi Zhang
- Center for Mitochondrial Biology and Medicine, The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi, 710049, China
| | - Xuan Zou
- National & Local Joint Engineering Research Center of Biodiagnosis and Biotherapy, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shannxi, 710004, China
| | - Xueqiang Wang
- Center for Mitochondrial Biology and Medicine, The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi, 710049, China
| | - Ke Cao
- Center for Mitochondrial Biology and Medicine, The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi, 710049, China
| | - Weiqiang Lv
- Center for Mitochondrial Biology and Medicine, The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi, 710049, China
| | - Yuting Cui
- Center for Mitochondrial Biology and Medicine, The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi, 710049, China
| | - Jiangang Long
- Center for Mitochondrial Biology and Medicine, The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi, 710049, China
| | - Zhihui Feng
- Center for Mitochondrial Biology and Medicine, The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi, 710049, China; Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi, 710049, China.
| | - Jiankang Liu
- Center for Mitochondrial Biology and Medicine, The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi, 710049, China; National & Local Joint Engineering Research Center of Biodiagnosis and Biotherapy, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shannxi, 710004, China; Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi, 710049, China.
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7
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Gagnon M, Savard M, Jacques JF, Bkaily G, Geha S, Roucou X, Gobeil F. Potentiation of B2 receptor signaling by AltB2R, a newly identified alternative protein encoded in the human bradykinin B2 receptor gene. J Biol Chem 2021; 296:100329. [PMID: 33497625 PMCID: PMC7949122 DOI: 10.1016/j.jbc.2021.100329] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 01/12/2021] [Accepted: 01/21/2021] [Indexed: 12/27/2022] Open
Abstract
Recent functional and proteomic studies in eukaryotes (www.openprot.org) predict the translation of alternative open reading frames (AltORFs) in mature G-protein-coupled receptor (GPCR) mRNAs, including that of bradykinin B2 receptor (B2R). Our main objective was to determine the implication of a newly discovered AltORF resulting protein, termed AltB2R, in the known signaling properties of B2R using complementary methodological approaches. When ectopically expressed in HeLa cells, AltB2R presented predominant punctate cytoplasmic/perinuclear distribution and apparent cointeraction with B2R at plasma and endosomal/vesicular membranes. The presence of AltB2R increases intracellular [Ca2+] and ERK1/2-MAPK activation (via phosphorylation) following B2R stimulation. Moreover, HEK293A cells expressing mutant B2R lacking concomitant expression of AltB2R displayed significantly decreased maximal responses in agonist-stimulated Gαq-Gαi2/3-protein coupling, IP3 generation, and ERK1/2-MAPK activation as compared with wild-type controls. Conversely, there was no difference in cell-surface density as well as ligand-binding properties of B2R and in efficiencies of cognate agonists at promoting B2R internalization and β-arrestin 2 recruitment. Importantly, both AltB2R and B2R proteins were overexpressed in prostate and breast cancers, compared with their normal counterparts suggesting new associative roles of AltB2R in these diseases. Our study shows that BDKRB2 is a dual-coding gene and identifies AltB2R as a novel positive modulator of some B2R signaling pathways. More broadly, it also supports a new, unexpected alternative proteome for GPCRs, which opens new frontiers in fields of GPCR biology, diseases, and drug discovery.
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Affiliation(s)
- Maxime Gagnon
- Department of Biochemistry, Université de Sherbrooke, Sherbrooke, Québec, Canada; Institute of Pharmacology, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Martin Savard
- Department of Pharmacology & Physiology, Université de Sherbrooke, Sherbrooke, Québec, Canada; Institute of Pharmacology, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Jean-François Jacques
- Department of Pharmacology & Physiology, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Ghassan Bkaily
- Department of Immunology & Cellular Biology, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Sameh Geha
- Department of Pathology, Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, Québec, Canada
| | - Xavier Roucou
- Department of Biochemistry, Université de Sherbrooke, Sherbrooke, Québec, Canada; Institute of Pharmacology, Université de Sherbrooke, Sherbrooke, Québec, Canada.
| | - Fernand Gobeil
- Department of Pharmacology & Physiology, Université de Sherbrooke, Sherbrooke, Québec, Canada; Institute of Pharmacology, Université de Sherbrooke, Sherbrooke, Québec, Canada.
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8
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Alt-RPL36 downregulates the PI3K-AKT-mTOR signaling pathway by interacting with TMEM24. Nat Commun 2021; 12:508. [PMID: 33479206 PMCID: PMC7820019 DOI: 10.1038/s41467-020-20841-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Accepted: 12/21/2020] [Indexed: 12/11/2022] Open
Abstract
Thousands of human small and alternative open reading frames (smORFs and alt-ORFs, respectively) have recently been annotated. Many alt-ORFs are co-encoded with canonical proteins in multicistronic configurations, but few of their functions are known. Here, we report the detection of alt-RPL36, a protein co-encoded with human RPL36. Alt-RPL36 partially localizes to the endoplasmic reticulum, where it interacts with TMEM24, which transports the phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) precursor phosphatidylinositol from the endoplasmic reticulum to the plasma membrane. Knock-out of alt-RPL36 increases plasma membrane PI(4,5)P2 levels, upregulates PI3K-AKT-mTOR signaling, and increases cell size. Alt-RPL36 contains four phosphoserine residues, point mutations of which abolish interaction with TMEM24 and, consequently, alt-RPL36 effects on PI3K signaling and cell size. These results implicate alt-RPL36 as an upstream regulator of PI3K-AKT-mTOR signaling. More broadly, the RPL36 transcript encodes two sequence-independent polypeptides that co-regulate translation via different molecular mechanisms, expanding our knowledge of multicistronic human gene functions. Many alternative ORFs are co-encoded with characterized proteins, but their function is often not understood. Here, the authors discover that ribosomal protein L36 is co-encoded with alternative protein, which they identify as an upstream regulator of PI3K-AKT-mTOR signaling.
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9
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Rath S, Sharma R, Gupta R, Ast T, Chan C, Durham TJ, Goodman RP, Grabarek Z, Haas ME, Hung WHW, Joshi PR, Jourdain AA, Kim SH, Kotrys AV, Lam SS, McCoy JG, Meisel JD, Miranda M, Panda A, Patgiri A, Rogers R, Sadre S, Shah H, Skinner OS, To TL, Walker M, Wang H, Ward PS, Wengrod J, Yuan CC, Calvo SE, Mootha VK. MitoCarta3.0: an updated mitochondrial proteome now with sub-organelle localization and pathway annotations. Nucleic Acids Res 2020; 49:D1541-D1547. [PMID: 33174596 PMCID: PMC7778944 DOI: 10.1093/nar/gkaa1011] [Citation(s) in RCA: 624] [Impact Index Per Article: 156.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 10/12/2020] [Accepted: 10/14/2020] [Indexed: 02/04/2023] Open
Abstract
The mammalian mitochondrial proteome is under dual genomic control, with 99% of proteins encoded by the nuclear genome and 13 originating from the mitochondrial DNA (mtDNA). We previously developed MitoCarta, a catalogue of over 1000 genes encoding the mammalian mitochondrial proteome. This catalogue was compiled using a Bayesian integration of multiple sequence features and experimental datasets, notably protein mass spectrometry of mitochondria isolated from fourteen murine tissues. Here, we introduce MitoCarta3.0. Beginning with the MitoCarta2.0 inventory, we performed manual review to remove 100 genes and introduce 78 additional genes, arriving at an updated inventory of 1136 human genes. We now include manually curated annotations of sub-mitochondrial localization (matrix, inner membrane, intermembrane space, outer membrane) as well as assignment to 149 hierarchical 'MitoPathways' spanning seven broad functional categories relevant to mitochondria. MitoCarta3.0, including sub-mitochondrial localization and MitoPathway annotations, is freely available at http://www.broadinstitute.org/mitocarta and should serve as a continued community resource for mitochondrial biology and medicine.
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Affiliation(s)
| | | | | | - Tslil Ast
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA,Howard Hughes Medical Institute and Departments of Molecular Biology and Medicine, Massachusetts General Hospital, Boston, MA 02114, USA,Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Connie Chan
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA,Howard Hughes Medical Institute and Departments of Molecular Biology and Medicine, Massachusetts General Hospital, Boston, MA 02114, USA,Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Timothy J Durham
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA,Howard Hughes Medical Institute and Departments of Molecular Biology and Medicine, Massachusetts General Hospital, Boston, MA 02114, USA,Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Russell P Goodman
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA,Howard Hughes Medical Institute and Departments of Molecular Biology and Medicine, Massachusetts General Hospital, Boston, MA 02114, USA,Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Zenon Grabarek
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA,Howard Hughes Medical Institute and Departments of Molecular Biology and Medicine, Massachusetts General Hospital, Boston, MA 02114, USA,Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Mary E Haas
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA,Howard Hughes Medical Institute and Departments of Molecular Biology and Medicine, Massachusetts General Hospital, Boston, MA 02114, USA,Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Wendy H W Hung
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA,Howard Hughes Medical Institute and Departments of Molecular Biology and Medicine, Massachusetts General Hospital, Boston, MA 02114, USA,Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Pallavi R Joshi
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA,Howard Hughes Medical Institute and Departments of Molecular Biology and Medicine, Massachusetts General Hospital, Boston, MA 02114, USA,Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Alexis A Jourdain
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA,Howard Hughes Medical Institute and Departments of Molecular Biology and Medicine, Massachusetts General Hospital, Boston, MA 02114, USA,Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Sharon H Kim
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA,Howard Hughes Medical Institute and Departments of Molecular Biology and Medicine, Massachusetts General Hospital, Boston, MA 02114, USA,Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Anna V Kotrys
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA,Howard Hughes Medical Institute and Departments of Molecular Biology and Medicine, Massachusetts General Hospital, Boston, MA 02114, USA,Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Stephanie S Lam
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA,Howard Hughes Medical Institute and Departments of Molecular Biology and Medicine, Massachusetts General Hospital, Boston, MA 02114, USA,Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Jason G McCoy
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA,Howard Hughes Medical Institute and Departments of Molecular Biology and Medicine, Massachusetts General Hospital, Boston, MA 02114, USA,Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Joshua D Meisel
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA,Howard Hughes Medical Institute and Departments of Molecular Biology and Medicine, Massachusetts General Hospital, Boston, MA 02114, USA,Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Maria Miranda
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA,Howard Hughes Medical Institute and Departments of Molecular Biology and Medicine, Massachusetts General Hospital, Boston, MA 02114, USA,Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Apekshya Panda
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA,Howard Hughes Medical Institute and Departments of Molecular Biology and Medicine, Massachusetts General Hospital, Boston, MA 02114, USA,Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Anupam Patgiri
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA,Howard Hughes Medical Institute and Departments of Molecular Biology and Medicine, Massachusetts General Hospital, Boston, MA 02114, USA,Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Robert Rogers
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA,Howard Hughes Medical Institute and Departments of Molecular Biology and Medicine, Massachusetts General Hospital, Boston, MA 02114, USA,Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Shayan Sadre
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA,Howard Hughes Medical Institute and Departments of Molecular Biology and Medicine, Massachusetts General Hospital, Boston, MA 02114, USA,Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Hardik Shah
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA,Howard Hughes Medical Institute and Departments of Molecular Biology and Medicine, Massachusetts General Hospital, Boston, MA 02114, USA,Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Owen S Skinner
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA,Howard Hughes Medical Institute and Departments of Molecular Biology and Medicine, Massachusetts General Hospital, Boston, MA 02114, USA,Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Tsz-Leung To
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA,Howard Hughes Medical Institute and Departments of Molecular Biology and Medicine, Massachusetts General Hospital, Boston, MA 02114, USA,Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Melissa A Walker
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA,Howard Hughes Medical Institute and Departments of Molecular Biology and Medicine, Massachusetts General Hospital, Boston, MA 02114, USA,Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Hong Wang
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA,Howard Hughes Medical Institute and Departments of Molecular Biology and Medicine, Massachusetts General Hospital, Boston, MA 02114, USA,Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Patrick S Ward
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA,Howard Hughes Medical Institute and Departments of Molecular Biology and Medicine, Massachusetts General Hospital, Boston, MA 02114, USA,Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Jordan Wengrod
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA,Howard Hughes Medical Institute and Departments of Molecular Biology and Medicine, Massachusetts General Hospital, Boston, MA 02114, USA,Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Chen-Ching Yuan
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA,Howard Hughes Medical Institute and Departments of Molecular Biology and Medicine, Massachusetts General Hospital, Boston, MA 02114, USA,Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Sarah E Calvo
- Correspondence may also be addressed to Sarah E. Calvo.
| | - Vamsi K Mootha
- To whom correspondence should be addressed. Tel: +1 617 643 3059;
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10
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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: 50] [Impact Index Per Article: 12.5] [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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11
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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: 5] [Impact Index Per Article: 1.3] [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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12
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Brunet MA, Brunelle M, Lucier JF, Delcourt V, Levesque M, Grenier F, Samandi S, Leblanc S, Aguilar JD, Dufour P, Jacques JF, Fournier I, Ouangraoua A, Scott MS, Boisvert FM, Roucou X. OpenProt: a more comprehensive guide to explore eukaryotic coding potential and proteomes. Nucleic Acids Res 2020; 47:D403-D410. [PMID: 30299502 PMCID: PMC6323990 DOI: 10.1093/nar/gky936] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Accepted: 10/04/2018] [Indexed: 01/06/2023] Open
Abstract
Advances in proteomics and sequencing have highlighted many non-annotated open reading frames (ORFs) in eukaryotic genomes. Genome annotations, cornerstones of today's research, mostly rely on protein prior knowledge and on ab initio prediction algorithms. Such algorithms notably enforce an arbitrary criterion of one coding sequence (CDS) per transcript, leading to a substantial underestimation of the coding potential of eukaryotes. Here, we present OpenProt, the first database fully endorsing a polycistronic model of eukaryotic genomes to date. OpenProt contains all possible ORFs longer than 30 codons across 10 species, and cumulates supporting evidence such as protein conservation, translation and expression. OpenProt annotates all known proteins (RefProts), novel predicted isoforms (Isoforms) and novel predicted proteins from alternative ORFs (AltProts). It incorporates cutting-edge algorithms to evaluate protein orthology and re-interrogate publicly available ribosome profiling and mass spectrometry datasets, supporting the annotation of thousands of predicted ORFs. The constantly growing database currently cumulates evidence from 87 ribosome profiling and 114 mass spectrometry studies from several species, tissues and cell lines. All data is freely available and downloadable from a web platform (www.openprot.org) supporting a genome browser and advanced queries for each species. Thus, OpenProt enables a more comprehensive landscape of eukaryotic genomes’ coding potential.
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Affiliation(s)
- Marie A Brunet
- Department of Biochemistry, Université de Sherbrooke, Sherbrooke, Québec, Canada.,PROTEO, Quebec Network for Research on Protein Function, Structure, and Engineering, Université de Lille, F-59000 Lille, France
| | - Mylène Brunelle
- Department of Biochemistry, Université de Sherbrooke, Sherbrooke, Québec, Canada.,PROTEO, Quebec Network for Research on Protein Function, Structure, and Engineering, Université de Lille, F-59000 Lille, France
| | - Jean-François Lucier
- Center for Computational Science, Université de Sherbrooke, Sherbrooke, Québec, Canada.,Biology Department, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Vivian Delcourt
- Department of Biochemistry, Université de Sherbrooke, Sherbrooke, Québec, Canada.,PROTEO, Quebec Network for Research on Protein Function, Structure, and Engineering, Université de Lille, F-59000 Lille, France.,INSERM U1192, Laboratoire Protéomique, Réponse Inflammatoire & Spectrométrie de Masse (PRISM), Université de Lille, F-59000 Lille, France
| | - Maxime Levesque
- Center for Computational Science, Université de Sherbrooke, Sherbrooke, Québec, Canada.,Biology Department, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Frédéric Grenier
- Center for Computational Science, Université de Sherbrooke, Sherbrooke, Québec, Canada.,Biology Department, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Sondos Samandi
- Department of Biochemistry, Université de Sherbrooke, Sherbrooke, Québec, Canada.,PROTEO, Quebec Network for Research on Protein Function, Structure, and Engineering, Université de Lille, F-59000 Lille, France
| | - Sébastien Leblanc
- Department of Biochemistry, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Jean-David Aguilar
- Department of Biochemistry, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Pascal Dufour
- Department of Biochemistry, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Jean-Francois Jacques
- Department of Biochemistry, Université de Sherbrooke, Sherbrooke, Québec, Canada.,PROTEO, Quebec Network for Research on Protein Function, Structure, and Engineering, Université de Lille, F-59000 Lille, France
| | - Isabelle Fournier
- INSERM U1192, Laboratoire Protéomique, Réponse Inflammatoire & Spectrométrie de Masse (PRISM), Université de Lille, F-59000 Lille, France
| | - Aida Ouangraoua
- Informatics Department, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Michelle S Scott
- Department of Biochemistry, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | | | - Xavier Roucou
- Department of Biochemistry, Université de Sherbrooke, Sherbrooke, Québec, Canada.,PROTEO, Quebec Network for Research on Protein Function, Structure, and Engineering, Université de Lille, F-59000 Lille, France
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13
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Nartey MN, Peña-Castillo L, LeGrow M, Doré J, Bhattacharya S, Darby-King A, Carew SJ, Yuan Q, Harley CW, McLean JH. Learning-induced mRNA alterations in olfactory bulb mitral cells in neonatal rats. ACTA ACUST UNITED AC 2020; 27:209-221. [PMID: 32295841 PMCID: PMC7164515 DOI: 10.1101/lm.051177.119] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2019] [Accepted: 02/11/2020] [Indexed: 12/20/2022]
Abstract
In the olfactory bulb, a cAMP/PKA/CREB-dependent form of learning occurs in the first week of life that provides a unique mammalian model for defining the epigenetic role of this evolutionarily ancient plasticity cascade. Odor preference learning in the week-old rat pup is rapidly induced by a 10-min pairing of odor and stroking. Memory is demonstrable at 24 h, but not 48 h, posttraining. Using this paradigm, pups that showed peppermint preference 30 min posttraining were sacrificed 20 min later for laser microdissection of odor-encoding mitral cells. Controls were given odor only. Microarray analysis revealed that 13 nonprotein-coding mRNAs linked to mRNA translation and splicing and 11 protein-coding mRNAs linked to transcription differed with odor preference training. MicroRNA23b, a translation inhibitor of multiple plasticity-related mRNAs, was down-regulated. Protein-coding transcription was up-regulated for Sec23b, Clic2, Rpp14, Dcbld1, Magee2, Mstn, Fam229b, RGD1566265, and Mgst2. Gng12 and Srcg1 mRNAs were down-regulated. Increases in Sec23b, Clic2, and Dcbld1 proteins were confirmed in mitral cells in situ at the same time point following training. The protein-coding changes are consistent with extracellular matrix remodeling and ryanodine receptor involvement in odor preference learning. A role for CREB and AP1 as triggers of memory-related mRNA regulation is supported. The small number of gene changes identified in the mitral cell input/output link for 24 h memory will facilitate investigation of the nature, and reversibility, of changes supporting temporally restricted long-term memory.
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Affiliation(s)
- Michaelina N Nartey
- Divison of Biomedical Sciences, Memorial University of Newfoundland, St. John's, Newfoundland A1B3V6, Canada
| | - Lourdes Peña-Castillo
- Department of Computer Science, Memorial University of Newfoundland, St. John's, Newfoundland A1B3X5, Canada
| | - Megan LeGrow
- Divison of Biomedical Sciences, Memorial University of Newfoundland, St. John's, Newfoundland A1B3V6, Canada
| | - Jules Doré
- Divison of Biomedical Sciences, Memorial University of Newfoundland, St. John's, Newfoundland A1B3V6, Canada
| | - Sriya Bhattacharya
- Divison of Biomedical Sciences, Memorial University of Newfoundland, St. John's, Newfoundland A1B3V6, Canada
| | - Andrea Darby-King
- Divison of Biomedical Sciences, Memorial University of Newfoundland, St. John's, Newfoundland A1B3V6, Canada
| | - Samantha J Carew
- Divison of Biomedical Sciences, Memorial University of Newfoundland, St. John's, Newfoundland A1B3V6, Canada
| | - Qi Yuan
- Divison of Biomedical Sciences, Memorial University of Newfoundland, St. John's, Newfoundland A1B3V6, Canada
| | - Carolyn W Harley
- Department of Psychology, Memorial University of Newfoundland, St. John's, Newfoundland A1B3X9, Canada
| | - John H McLean
- Divison of Biomedical Sciences, Memorial University of Newfoundland, St. John's, Newfoundland A1B3V6, Canada
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14
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Abstract
Biology students today are taught that mitochondria are 'the powerhouse of the cell'. This gross over-simplification of their cellular role has arguably led to a paucity of knowledge concerning the many other tasks carried out by this multifunctional organelle. Mitochondrial fatty acid synthesis (mtFAS) is one such under-appreciated pathway that is crucial for mitochondrial function, although even mitochondrial experts are often surprised to learn of its existence. For many years, the only function of mtFAS was thought to be the production of lipoic acid, an important co-factor for several mitochondrial enzymes. However, recent advances have revealed a far wider role for mtFAS in mitochondrial physiology. The discovery of human patients with mutations in mtFAS enzymes has brought renewed interest in understanding the full significance of this novel mode of mitochondrial metabolic regulation. We now appreciate that mtFAS is a nutrient-sensitive pathway that provides an elegant mechanism whereby acetyl-CoA regulates its own consumption via coordination of lipoic acid synthesis and tricarboxylic acid (TCA) cycle activity, iron-sulfur (FeS) cluster biogenesis, assembly of oxidative phosphorylation complexes, and mitochondrial translation. In this minireview, we describe and build upon the important discoveries that led to our current understanding of this elegant mechanism of coordination of nutrient status and metabolism.
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15
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Jeong SY, Hogarth P, Placzek A, Gregory AM, Fox R, Zhen D, Hamada J, van der Zwaag M, Lambrechts R, Jin H, Nilsen A, Cobb J, Pham T, Gray N, Ralle M, Duffy M, Schwanemann L, Rai P, Freed A, Wakeman K, Woltjer RL, Sibon OCM, Hayflick SJ. 4'-Phosphopantetheine corrects CoA, iron, and dopamine metabolic defects in mammalian models of PKAN. EMBO Mol Med 2019; 11:e10489. [PMID: 31660701 PMCID: PMC6895607 DOI: 10.15252/emmm.201910489] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Revised: 08/07/2019] [Accepted: 08/14/2019] [Indexed: 11/19/2022] Open
Abstract
Pantothenate kinase-associated neurodegeneration (PKAN) is an inborn error of CoA metabolism causing dystonia, parkinsonism, and brain iron accumulation. Lack of a good mammalian model has impeded studies of pathogenesis and development of rational therapeutics. We took a new approach to investigating an existing mouse mutant of Pank2 and found that isolating the disease-vulnerable brain revealed regional perturbations in CoA metabolism, iron homeostasis, and dopamine metabolism and functional defects in complex I and pyruvate dehydrogenase. Feeding mice a CoA pathway intermediate, 4'-phosphopantetheine, normalized levels of the CoA-, iron-, and dopamine-related biomarkers as well as activities of mitochondrial enzymes. Human cell changes also were recovered by 4'-phosphopantetheine. We can mechanistically link a defect in CoA metabolism to these secondary effects via the activation of mitochondrial acyl carrier protein, which is essential to oxidative phosphorylation, iron-sulfur cluster biogenesis, and mitochondrial fatty acid synthesis. We demonstrate the fidelity of our model in recapitulating features of the human disease. Moreover, we identify pharmacodynamic biomarkers, provide insights into disease pathogenesis, and offer evidence for 4'-phosphopantetheine as a candidate therapeutic for PKAN.
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Affiliation(s)
- Suh Young Jeong
- Department of Molecular & Medical GeneticsOregon Health & Science UniversityPortlandORUSA
| | - Penelope Hogarth
- Department of Molecular & Medical GeneticsOregon Health & Science UniversityPortlandORUSA
- Department of NeurologyOregon Health & Science UniversityPortlandORUSA
| | - Andrew Placzek
- Medicinal Chemistry CoreOregon Health & Science UniversityPortlandORUSA
| | - Allison M Gregory
- Department of Molecular & Medical GeneticsOregon Health & Science UniversityPortlandORUSA
| | - Rachel Fox
- Department of Molecular & Medical GeneticsOregon Health & Science UniversityPortlandORUSA
| | - Dolly Zhen
- Department of Molecular & Medical GeneticsOregon Health & Science UniversityPortlandORUSA
| | - Jeffrey Hamada
- Department of Molecular & Medical GeneticsOregon Health & Science UniversityPortlandORUSA
| | | | - Roald Lambrechts
- Department of Cell BiologyUniversity Medical Center GroningenGroningenthe Netherlands
| | - Haihong Jin
- Medicinal Chemistry CoreOregon Health & Science UniversityPortlandORUSA
| | - Aaron Nilsen
- Medicinal Chemistry CoreOregon Health & Science UniversityPortlandORUSA
| | - Jared Cobb
- Department of PathologyOregon Health & Science UniversityPortlandORUSA
| | - Thao Pham
- Department of PathologyOregon Health & Science UniversityPortlandORUSA
| | - Nora Gray
- Department of NeurologyOregon Health & Science UniversityPortlandORUSA
| | - Martina Ralle
- Department of Molecular & Medical GeneticsOregon Health & Science UniversityPortlandORUSA
| | - Megan Duffy
- Department of Molecular & Medical GeneticsOregon Health & Science UniversityPortlandORUSA
| | - Leila Schwanemann
- Department of Molecular & Medical GeneticsOregon Health & Science UniversityPortlandORUSA
| | - Puneet Rai
- Department of Molecular & Medical GeneticsOregon Health & Science UniversityPortlandORUSA
| | - Alison Freed
- Department of Molecular & Medical GeneticsOregon Health & Science UniversityPortlandORUSA
| | - Katrina Wakeman
- Department of Molecular & Medical GeneticsOregon Health & Science UniversityPortlandORUSA
| | - Randall L Woltjer
- Department of PathologyOregon Health & Science UniversityPortlandORUSA
| | - Ody CM Sibon
- Department of Cell BiologyUniversity Medical Center GroningenGroningenthe Netherlands
| | - Susan J Hayflick
- Department of Molecular & Medical GeneticsOregon Health & Science UniversityPortlandORUSA
- Department of NeurologyOregon Health & Science UniversityPortlandORUSA
- Department of PediatricsOregon Health & Science UniversityPortlandORUSA
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16
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Masud AJ, Kastaniotis AJ, Rahman MT, Autio KJ, Hiltunen JK. Mitochondrial acyl carrier protein (ACP) at the interface of metabolic state sensing and mitochondrial function. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2019; 1866:118540. [PMID: 31473256 DOI: 10.1016/j.bbamcr.2019.118540] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 08/23/2019] [Accepted: 08/27/2019] [Indexed: 12/20/2022]
Abstract
Acyl carrier protein (ACP) is a principal partner in the cytosolic and mitochondrial fatty acid synthesis (FAS) pathways. The active form holo-ACP serves as FAS platform, using its 4'-phosphopantetheine group to present covalently attached FAS intermediates to the enzymes responsible for the acyl chain elongation process. Mitochondrial unacylated holo-ACP is a component of mammalian mitoribosomes, and acylated ACP species participate as interaction partners in several ACP-LYRM (leucine-tyrosine-arginine motif)-protein heterodimers that act either as assembly factors or subunits of the electron transport chain and Fe-S cluster assembly complexes. Moreover, octanoyl-ACP provides the C8 backbone for endogenous lipoic acid synthesis. Accumulating evidence suggests that mtFAS-generated acyl-ACPs act as signaling molecules in an intramitochondrial metabolic state sensing circuit, coordinating mitochondrial acetyl-CoA levels with mitochondrial respiration, Fe-S cluster biogenesis and protein lipoylation.
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Affiliation(s)
- Ali J Masud
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland
| | | | - M Tanvir Rahman
- 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
| | - J Kalervo Hiltunen
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland.
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17
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Heil CS, Wehrheim SS, Paithankar KS, Grininger M. Fatty Acid Biosynthesis: Chain‐Length Regulation and Control. Chembiochem 2019; 20:2298-2321. [DOI: 10.1002/cbic.201800809] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 03/20/2019] [Indexed: 12/18/2022]
Affiliation(s)
- Christina S. Heil
- Institute of Organic Chemistry and Chemical BiologyBuchmann Institute for Molecular Life ScienceGoethe University Frankfurt Max-von-Laue-Strasse 15 60438 Frankfurt am Main Germany
| | - S. Sophia Wehrheim
- Institute of Organic Chemistry and Chemical BiologyBuchmann Institute for Molecular Life ScienceGoethe University Frankfurt Max-von-Laue-Strasse 15 60438 Frankfurt am Main Germany
| | - Karthik S. Paithankar
- Institute of Organic Chemistry and Chemical BiologyBuchmann Institute for Molecular Life ScienceGoethe University Frankfurt Max-von-Laue-Strasse 15 60438 Frankfurt am Main Germany
| | - Martin Grininger
- Institute of Organic Chemistry and Chemical BiologyBuchmann Institute for Molecular Life ScienceGoethe University Frankfurt Max-von-Laue-Strasse 15 60438 Frankfurt am Main Germany
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18
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Lorenzo-Orts L, Witthoeft J, Deforges J, Martinez J, Loubéry S, Placzek A, Poirier Y, Hothorn LA, Jaillais Y, Hothorn M. Concerted expression of a cell cycle regulator and a metabolic enzyme from a bicistronic transcript in plants. NATURE PLANTS 2019; 5:184-193. [PMID: 30737513 DOI: 10.1038/s41477-019-0358-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Accepted: 01/04/2019] [Indexed: 05/15/2023]
Abstract
Eukaryotic mRNAs frequently contain upstream open reading frames (uORFs), encoding small peptides that may control translation of the main ORF (mORF). Here, we report the characterization of a distinct bicistronic transcript in Arabidopsis. We analysed loss-of-function phenotypes of the inorganic polyphosphatase TRIPHOSPHATE TUNNEL METALLOENZYME 3 (AtTTM3), and found that catalytically inactive versions of the enzyme could fully complement embryo and growth-related phenotypes. We could rationalize these puzzling findings by characterizing a uORF in the AtTTM3 locus encoding CELL DIVISION CYCLE PROTEIN 26 (CDC26), an orthologue of the cell cycle regulator. We demonstrate that AtCDC26 is part of the plant anaphase promoting complex/cyclosome (APC/C), regulates accumulation of APC/C target proteins and controls cell division, growth and embryo development. AtCDC26 and AtTTM3 are translated from a single transcript conserved across the plant lineage. While there is no apparent biochemical connection between the two gene products, AtTTM3 coordinates AtCDC26 translation by recruiting the transcript into polysomes. Our work highlights that uORFs may encode functional proteins in plant genomes.
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Affiliation(s)
- Laura Lorenzo-Orts
- Structural Plant Biology Laboratory, Department of Botany and Plant Biology, University of Geneva, Geneva, Switzerland.
| | - Janika Witthoeft
- Friedrich Miescher Laboratory of the Max Planck Society, Tübingen, Germany
| | - Jules Deforges
- Department of Plant Molecular Biology, University of Lausanne, Lausanne, Switzerland
| | - Jacobo Martinez
- Structural Plant Biology Laboratory, Department of Botany and Plant Biology, University of Geneva, Geneva, Switzerland
- Friedrich Miescher Laboratory of the Max Planck Society, Tübingen, Germany
| | - Sylvain Loubéry
- Department of Botany and Plant Biology, University of Geneva, Geneva, Switzerland
| | - Aleksandra Placzek
- Friedrich Miescher Laboratory of the Max Planck Society, Tübingen, Germany
- Max Planck Institute for Biology of Ageing, Cologne, Germany
| | - Yves Poirier
- Department of Plant Molecular Biology, University of Lausanne, Lausanne, Switzerland
| | - Ludwig A Hothorn
- Institute of Biostatistics, Leibniz University, Hannover, Germany
| | - Yvon Jaillais
- Laboratoire Reproduction et Développement des Plantes, Université de Lyon, ENS de Lyon, UCB Lyon 1, CNRS, INRA, Lyon, France
| | - Michael Hothorn
- Structural Plant Biology Laboratory, Department of Botany and Plant Biology, University of Geneva, Geneva, Switzerland.
- Friedrich Miescher Laboratory of the Max Planck Society, Tübingen, Germany.
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19
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Brunet MA, Levesque SA, Hunting DJ, Cohen AA, Roucou X. Recognition of the polycistronic nature of human genes is critical to understanding the genotype-phenotype relationship. Genome Res 2018; 28:609-624. [PMID: 29626081 PMCID: PMC5932603 DOI: 10.1101/gr.230938.117] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Accepted: 03/27/2018] [Indexed: 12/12/2022]
Abstract
Technological advances promise unprecedented opportunities for whole exome sequencing and proteomic analyses of populations. Currently, data from genome and exome sequencing or proteomic studies are searched against reference genome annotations. This provides the foundation for research and clinical screening for genetic causes of pathologies. However, current genome annotations substantially underestimate the proteomic information encoded within a gene. Numerous studies have now demonstrated the expression and function of alternative (mainly small, sometimes overlapping) ORFs within mature gene transcripts. This has important consequences for the correlation of phenotypes and genotypes. Most alternative ORFs are not yet annotated because of a lack of evidence, and this absence from databases precludes their detection by standard proteomic methods, such as mass spectrometry. Here, we demonstrate how current approaches tend to overlook alternative ORFs, hindering the discovery of new genetic drivers and fundamental research. We discuss available tools and techniques to improve identification of proteins from alternative ORFs and finally suggest a novel annotation system to permit a more complete representation of the transcriptomic and proteomic information contained within a gene. Given the crucial challenge of distinguishing functional ORFs from random ones, the suggested pipeline emphasizes both experimental data and conservation signatures. The addition of alternative ORFs in databases will render identification less serendipitous and advance the pace of research and genomic knowledge. This review highlights the urgent medical and research need to incorporate alternative ORFs in current genome annotations and thus permit their inclusion in hypotheses and models, which relate phenotypes and genotypes.
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Affiliation(s)
- Marie A Brunet
- Biochemistry Department, Université de Sherbrooke, Quebec J1E 4K8, Canada.,Groupe de recherche PRIMUS, Department of Family and Emergency Medicine, Quebec J1H 5N4, Canada.,PROTEO, Quebec Network for Research on Protein Function, Structure, and Engineering, Université Laval, Quebec G1V 0A6, Canada
| | - Sébastien A Levesque
- Pediatric Department, Centre Hospitalier de l'Université de Sherbrooke, Quebec J1H 5N4, Canada
| | - Darel J Hunting
- Department of Nuclear Medicine & Radiobiology, Université de Sherbrooke, Quebec J1H 5N4, Canada
| | - Alan A Cohen
- Groupe de recherche PRIMUS, Department of Family and Emergency Medicine, Quebec J1H 5N4, Canada
| | - Xavier Roucou
- Biochemistry Department, Université de Sherbrooke, Quebec J1E 4K8, Canada.,PROTEO, Quebec Network for Research on Protein Function, Structure, and Engineering, Université Laval, Quebec G1V 0A6, Canada
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20
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Kastaniotis AJ, Autio KJ, Kerätär JM, Monteuuis G, Mäkelä AM, Nair RR, Pietikäinen LP, Shvetsova A, Chen Z, Hiltunen JK. Mitochondrial fatty acid synthesis, fatty acids and mitochondrial physiology. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1862:39-48. [PMID: 27553474 DOI: 10.1016/j.bbalip.2016.08.011] [Citation(s) in RCA: 89] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2016] [Revised: 07/20/2016] [Accepted: 08/17/2016] [Indexed: 02/07/2023]
Abstract
Mitochondria and fatty acids are tightly connected to a multiplicity of cellular processes that go far beyond mitochondrial fatty acid metabolism. In line with this view, there is hardly any common metabolic disorder that is not associated with disturbed mitochondrial lipid handling. Among other aspects of mitochondrial lipid metabolism, apparently all eukaryotes are capable of carrying out de novo fatty acid synthesis (FAS) in this cellular compartment in an acyl carrier protein (ACP)-dependent manner. The dual localization of FAS in eukaryotic cells raises the questions why eukaryotes have maintained the FAS in mitochondria in addition to the "classic" cytoplasmic FAS and what the products are that cannot be substituted by delivery of fatty acids of extramitochondrial origin. The current evidence indicates that mitochondrial FAS is essential for cellular respiration and mitochondrial biogenesis. Although both β-oxidation and FAS utilize thioester chemistry, CoA acts as acyl-group carrier in the breakdown pathway whereas ACP assumes this role in the synthetic direction. This arrangement metabolically separates these two pathways running towards opposite directions and prevents futile cycling. A role of this pathway in mitochondrial metabolic sensing has recently been proposed. This article is part of a Special Issue entitled: Lipids of Mitochondria edited by Guenther Daum.
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Affiliation(s)
- Alexander J Kastaniotis
- Faculty of Biochemistry and Molecular Medicine, Biocenter Oulu, University of Oulu, Oulu, Finland.
| | - Kaija J Autio
- Faculty of Biochemistry and Molecular Medicine, Biocenter Oulu, University of Oulu, Oulu, Finland
| | - Juha M Kerätär
- Faculty of Biochemistry and Molecular Medicine, Biocenter Oulu, University of Oulu, Oulu, Finland
| | - Geoffray Monteuuis
- Faculty of Biochemistry and Molecular Medicine, Biocenter Oulu, University of Oulu, Oulu, Finland
| | - Anne M Mäkelä
- Faculty of Biochemistry and Molecular Medicine, Biocenter Oulu, University of Oulu, Oulu, Finland
| | - Remya R Nair
- Faculty of Biochemistry and Molecular Medicine, Biocenter Oulu, University of Oulu, Oulu, Finland
| | - Laura P Pietikäinen
- Faculty of Biochemistry and Molecular Medicine, Biocenter Oulu, University of Oulu, Oulu, Finland
| | - Antonina Shvetsova
- Faculty of Biochemistry and Molecular Medicine, Biocenter Oulu, University of Oulu, Oulu, Finland
| | - Zhijun Chen
- State Key Laboratory of Supramolecular Structure and Materials and Institute of Theoretical Chemistry, Jilin University, 2699 Qianjin Street, Changchun 130012, PR China
| | - J Kalervo Hiltunen
- Faculty of Biochemistry and Molecular Medicine, Biocenter Oulu, University of Oulu, Oulu, Finland; State Key Laboratory of Supramolecular Structure and Materials and Institute of Theoretical Chemistry, Jilin University, 2699 Qianjin Street, Changchun 130012, PR China.
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21
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Mouilleron H, Delcourt V, Roucou X. Death of a dogma: eukaryotic mRNAs can code for more than one protein. Nucleic Acids Res 2016; 44:14-23. [PMID: 26578573 PMCID: PMC4705651 DOI: 10.1093/nar/gkv1218] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Revised: 10/26/2015] [Accepted: 10/28/2015] [Indexed: 12/13/2022] Open
Abstract
mRNAs carry the genetic information that is translated by ribosomes. The traditional view of a mature eukaryotic mRNA is a molecule with three main regions, the 5' UTR, the protein coding open reading frame (ORF) or coding sequence (CDS), and the 3' UTR. This concept assumes that ribosomes translate one ORF only, generally the longest one, and produce one protein. As a result, in the early days of genomics and bioinformatics, one CDS was associated with each protein-coding gene. This fundamental concept of a single CDS is being challenged by increasing experimental evidence indicating that annotated proteins are not the only proteins translated from mRNAs. In particular, mass spectrometry (MS)-based proteomics and ribosome profiling have detected productive translation of alternative open reading frames. In several cases, the alternative and annotated proteins interact. Thus, the expression of two or more proteins translated from the same mRNA may offer a mechanism to ensure the co-expression of proteins which have functional interactions. Translational mechanisms already described in eukaryotic cells indicate that the cellular machinery is able to translate different CDSs from a single viral or cellular mRNA. In addition to summarizing data showing that the protein coding potential of eukaryotic mRNAs has been underestimated, this review aims to challenge the single translated CDS dogma.
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Affiliation(s)
- Hélène Mouilleron
- Department of biochemistry, Université de Sherbrooke, Sherbrooke, Quebec J1E 4K8, Canada PROTEO, Quebec Network for Research on Protein Function, Structure, and Engineering, Quebec, Canada
| | - Vivian Delcourt
- Department of biochemistry, Université de Sherbrooke, Sherbrooke, Quebec J1E 4K8, Canada PROTEO, Quebec Network for Research on Protein Function, Structure, and Engineering, Quebec, Canada Inserm U-1192, Laboratoire de Protéomique, Réponse Inflammatoire, Spectrométrie de Masse (PRISM), Université de Lille 1, Cité Scientifique, 59655 Villeneuve D'Ascq, France
| | - Xavier Roucou
- Department of biochemistry, Université de Sherbrooke, Sherbrooke, Quebec J1E 4K8, Canada PROTEO, Quebec Network for Research on Protein Function, Structure, and Engineering, Quebec, Canada
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22
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Andreev DE, O'Connor PBF, Zhdanov AV, Dmitriev RI, Shatsky IN, Papkovsky DB, Baranov PV. Oxygen and glucose deprivation induces widespread alterations in mRNA translation within 20 minutes. Genome Biol 2015; 16:90. [PMID: 25943107 PMCID: PMC4419486 DOI: 10.1186/s13059-015-0651-z] [Citation(s) in RCA: 94] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2015] [Accepted: 04/13/2015] [Indexed: 01/10/2023] Open
Abstract
Background Oxygen and glucose metabolism play pivotal roles in many (patho)physiological conditions. In particular, oxygen and glucose deprivation (OGD) during ischemia and stroke results in extensive tissue injury and cell death. Results Using time-resolved ribosome profiling, we assess gene expression levels in a neural cell line, PC12, during the first hour of OGD. The most substantial alterations are seen to occur within the first 20 minutes of OGD. While transcription of only 100 genes is significantly altered during one hour of OGD, the translation response affects approximately 3,000 genes. This response involves reprogramming of initiation and elongation rates, as well as the stringency of start codon recognition. Genes involved in oxidative phosphorylation are most affected. Detailed analysis of ribosome profiles reveals salient alterations of ribosome densities on individual mRNAs. The mRNA-specific alterations include increased translation of upstream open reading frames, site-specific ribosome pauses, and production of alternative protein isoforms with amino-terminal extensions. Detailed analysis of ribosomal profiles also reveals six mRNAs with translated ORFs occurring downstream of annotated coding regions and two examples of dual coding mRNAs, where two protein products are translated from the same long segment of mRNA, but in two different frames. Conclusions These findings uncover novel regulatory mechanisms of translational response to OGD in mammalian cells that are different from the classical pathways such as hypoxia inducible factor (HIF) signaling, while also revealing sophisticated organization of protein coding information in certain genes. Electronic supplementary material The online version of this article (doi:10.1186/s13059-015-0651-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Dmitry E Andreev
- School of Biochemistry and Cell Biology, Western Gateway Building, University College Cork, Cork, Ireland. .,Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119992, Russia.
| | - Patrick B F O'Connor
- School of Biochemistry and Cell Biology, Western Gateway Building, University College Cork, Cork, Ireland.
| | - Alexander V Zhdanov
- School of Biochemistry and Cell Biology, Western Gateway Building, University College Cork, Cork, Ireland.
| | - Ruslan I Dmitriev
- School of Biochemistry and Cell Biology, Western Gateway Building, University College Cork, Cork, Ireland.
| | - Ivan N Shatsky
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119992, Russia.
| | - Dmitri B Papkovsky
- School of Biochemistry and Cell Biology, Western Gateway Building, University College Cork, Cork, Ireland. .,Institute of Biomedical Chemistry, Pogodinskaya street, Moscow, 119121, Russia.
| | - Pavel V Baranov
- School of Biochemistry and Cell Biology, Western Gateway Building, University College Cork, Cork, Ireland.
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Suomi F, Menger KE, Monteuuis G, Naumann U, Kursu VAS, Shvetsova A, Kastaniotis AJ. Expression and evolution of the non-canonically translated yeast mitochondrial acetyl-CoA carboxylase Hfa1p. PLoS One 2014; 9:e114738. [PMID: 25503745 PMCID: PMC4263661 DOI: 10.1371/journal.pone.0114738] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Accepted: 11/13/2014] [Indexed: 12/16/2022] Open
Abstract
The Saccharomyces cerevisiae genome encodes two sequence related acetyl-CoA carboxylases, the cytosolic Acc1p and the mitochondrial Hfa1p, required for respiratory function. Several aspects of expression of the HFA1 gene and its evolutionary origin have remained unclear. Here, we determined the HFA1 transcription initiation sites by 5' RACE analysis. Using a novel "Stop codon scanning" approach, we mapped the location of the HFA1 translation initiation site to an upstream AUU codon at position -372 relative to the annotated start codon. This upstream initiation leads to production of a mitochondrial targeting sequence preceding the ACC domains of the protein. In silico analyses of fungal ACC genes revealed conserved "cryptic" upstream mitochondrial targeting sequences in yeast species that have not undergone a whole genome duplication. Our Δhfa1 baker's yeast mutant phenotype rescue studies using the protoploid Kluyveromyces lactis ACC confirmed functionality of the cryptic upstream mitochondrial targeting signal. These results lend strong experimental support to the hypothesis that the mitochondrial and cytosolic acetyl-CoA carboxylases in S. cerevisiae have evolved from a single gene encoding both the mitochondrial and cytosolic isoforms. Leaning on a cursory survey of a group of genes of our interest, we propose that cryptic 5' upstream mitochondrial targeting sequences may be more abundant in eukaryotes than anticipated thus far.
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Affiliation(s)
- Fumi Suomi
- Faculty of Biochemistry and Molecular Medicine and Biocenter Oulu, University of Oulu, Oulu, Finland
| | - Katja E Menger
- Faculty of Biochemistry and Molecular Medicine and Biocenter Oulu, University of Oulu, Oulu, Finland
| | - Geoffray Monteuuis
- Faculty of Biochemistry and Molecular Medicine and Biocenter Oulu, University of Oulu, Oulu, Finland
| | - Uta Naumann
- Faculty of Biochemistry and Molecular Medicine and Biocenter Oulu, University of Oulu, Oulu, Finland
| | - V A Samuli Kursu
- Faculty of Biochemistry and Molecular Medicine and Biocenter Oulu, University of Oulu, Oulu, Finland
| | - Antonina Shvetsova
- Faculty of Biochemistry and Molecular Medicine and Biocenter Oulu, University of Oulu, Oulu, Finland
| | - Alexander J Kastaniotis
- Faculty of Biochemistry and Molecular Medicine and Biocenter Oulu, University of Oulu, Oulu, Finland
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Mayr JA, Feichtinger RG, Tort F, Ribes A, Sperl W. Lipoic acid biosynthesis defects. J Inherit Metab Dis 2014; 37:553-63. [PMID: 24777537 DOI: 10.1007/s10545-014-9705-8] [Citation(s) in RCA: 146] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Revised: 03/11/2014] [Accepted: 03/12/2014] [Indexed: 01/10/2023]
Abstract
Lipoate is a covalently bound cofactor essential for five redox reactions in humans: in four 2-oxoacid dehydrogenases and the glycine cleavage system (GCS). Two enzymes are from the energy metabolism, α-ketoglutarate dehydrogenase and pyruvate dehydrogenase; and three are from the amino acid metabolism, branched-chain ketoacid dehydrogenase, 2-oxoadipate dehydrogenase, and the GCS. All these enzymes consist of multiple subunits and share a similar architecture. Lipoate synthesis in mitochondria involves mitochondrial fatty acid synthesis up to octanoyl-acyl-carrier protein; and three lipoate-specific steps, including octanoic acid transfer to glycine cleavage H protein by lipoyl(octanoyl) transferase 2 (putative) (LIPT2), lipoate synthesis by lipoic acid synthetase (LIAS), and lipoate transfer by lipoyltransferase 1 (LIPT1), which is necessary to lipoylate the E2 subunits of the 2-oxoacid dehydrogenases. The reduced form dihydrolipoate is reactivated by dihydrolipoyl dehydrogenase (DLD). Mutations in LIAS have been identified that result in a variant form of nonketotic hyperglycinemia with early-onset convulsions combined with a defect in mitochondrial energy metabolism with encephalopathy and cardiomyopathy. LIPT1 deficiency spares the GCS, and resulted in a combined 2-oxoacid dehydrogenase deficiency and early death in one patient and in a less severely affected individual with a Leigh-like phenotype. As LIAS is an iron-sulphur-cluster-dependent enzyme, a number of recently identified defects in mitochondrial iron-sulphur cluster synthesis, including NFU1, BOLA3, IBA57, GLRX5 presented with deficiency of LIAS and a LIAS-like phenotype. As in DLD deficiency, a broader clinical spectrum can be anticipated for lipoate synthesis defects depending on which of the affected enzymes is most rate limiting.
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Affiliation(s)
- Johannes A Mayr
- Department of Paediatrics, Paracelsus Medical University Salzburg, Salzburg, 5020, Austria,
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25
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Zhang Y, Ning F, Li X, Teng M. Structural insights into cofactor recognition of yeast mitochondria 3-oxoacyl-ACP reductase OAR1. IUBMB Life 2013; 65:154-62. [PMID: 23300157 DOI: 10.1002/iub.1125] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Accepted: 12/04/2012] [Indexed: 11/09/2022]
Abstract
3-Oxoacyl-(acyl-carrier-protein) reductase (OAR1 or FabG, EC.1.1.1.100) is responsible for the first reductive step in fatty acid biosynthesis using Nicotinamide Adenine Dinucleotide Phosphate (NADPH) as a cofactor. Recent studies suggest there is a fatty acid synthetase II pathway that consists of a series of separate enzymes in yeast mitochondrion. Here, we present the crystal structure of the yeast mitochondria OAR1 (ymtOAR1) alone in apo-form at 2.60 Å and complexed with NADPH at 2.10 Å resolution. Unlike the reported tetrameric OARs, ymtOAR1 forms a homodimer due to the different fold. The enzyme generates conformational changes upon NADPH binding to the active site. Moreover, two different cofactor-binding patterns are observed from two forms of complex crystals, and structural analysis implies the adenine end of cofactor may recognize enzyme prior to nicotinaminde end. Additionally, biochemical studies suggest Arg14 is important for cofactor recognition of ymtOAR1.
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Affiliation(s)
- YuJie Zhang
- Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, China
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26
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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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27
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Lu Y, Zhang Y, Hang X, Qu W, Lubec G, Chen C, Zhang C. Genome-wide computational identification of bicistronic mRNA in humans. Amino Acids 2012; 44:597-606. [PMID: 22945903 DOI: 10.1007/s00726-012-1380-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2012] [Accepted: 07/26/2012] [Indexed: 11/30/2022]
Abstract
Mammalian bicistronic mRNA is a recently discovered mammalian gene structure. Several reported cases of mammalian bicistronic mRNA indicated that genes of this structure play roles in some important biological processes. However, a genome-wide computational identification of bicistronic mRNA in mammalian genome, such as human genome, is still lacking. Here we used a comparative genomics approach to identify the frequency of human bicistronic mRNA. We then validated the result by using a new support vector machine (SVM) model. We identified 43 human bicistronic mRNAs in 30 distinct genes. Our literature analysis shows that our method recovered 100 % (6/6) of the previously known bicistronic mRNAs which had been experimentally confirmed by other groups. Our graph theory-based analysis and GO analysis indicated that human bicistronic mRNAs are prone to produce different yet closely functionally related proteins. In addition, we also described and analyzed three different mechanisms of ORF fusion. Our method of identifying bicistronic mRNAs in human genome provides a model for the computational identification of characteristic gene structures in mammalian genomes. We anticipate that our data will facilitate further molecular characterization and functional study of human bicistronic mRNA.
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Affiliation(s)
- Yiming Lu
- Beijing Institute of Radiation Medicine, State Key Laboratory of Proteomics, Cognitive and Mental Health Research Center, Beijing 100850, China
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28
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Cantu DC, Dai T, Beversdorf ZS, Reilly PJ. Structural classification and properties of ketoacyl reductases, hydroxyacyl dehydratases and enoyl reductases. Protein Eng Des Sel 2012; 25:803-11. [DOI: 10.1093/protein/gzs050] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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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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30
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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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Abstract
FA (fatty acid) synthesis represents a central, conserved process by which acyl chains are produced for utilization in a number of end-products such as biological membranes. Central to FA synthesis, the ACP (acyl carrier protein) represents the cofactor protein that covalently binds all fatty acyl intermediates via a phosphopantetheine linker during the synthesis process. FASs (FA synthases) can be divided into two classes, type I and II, which are primarily present in eukaryotes and bacteria/plants respectively. They are characterized by being composed of either large multifunctional polypeptides in the case of type I or consisting of discretely expressed mono-functional proteins in the type II system. Owing to this difference in architecture, the FAS system has been thought to be a good target for the discovery of novel antibacterial agents, as exemplified by the antituberculosis drug isoniazid. There have been considerable advances in this field in recent years, including the first high-resolution structural insights into the type I mega-synthases and their dynamic behaviour. Furthermore, the structural and dynamic properties of an increasing number of acyl-ACPs have been described, leading to an improved comprehension of this central carrier protein. In the present review we discuss the state of the understanding of FA synthesis with a focus on ACP. In particular, developments made over the past few years are highlighted.
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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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Identification of the Leishmania major proteins LmjF07.0430, LmjF07.0440, and LmjF27.2440 as components of fatty acid synthase II. J Biomed Biotechnol 2010; 2009:950864. [PMID: 20145708 PMCID: PMC2817374 DOI: 10.1155/2009/950864] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2009] [Accepted: 10/23/2009] [Indexed: 11/18/2022] Open
Abstract
Leishmania major causes leishmaniasis and is grouped within the Trypanosomatidae family, which also includes the etiologic agent for African sleeping sickness, Trypanosoma brucei. Previous studies on T. brucei showed that acyl carrier protein (ACP) of mitochondrial fatty acid synthase type 2 (FASII) plays a crucial role in parasite survival. Additionally, 3-oxoacyl-ACP synthase TbKASIII as well as TbHTD2 representing 3-hydroxyacyl-ACP dehydratase were also identified; however, 3-oxoacyl-ACP reductase TbKAR1 has hitherto evaded positive identification. Here, potential Leishmania FASII components LmjF07.0440 and LmjF07.0430 were revealed as 3-hydroxyacyl-ACP dehydratases LmHTD2-1 and LmHTD2-2, respectively, whereas LmjF27.2440 was identified as LmKAR1. These Leishmania proteins were ectopically expressed in Saccharomyces cerevisiae htd2Delta or oar1Delta respiratory deficient cells lacking the corresponding mitochondrial FASII enzymes Htd2p and Oar1p. Yeast mutants producing mitochondrially targeted versions of the parasite proteins resembled the self-complemented cells for respiratory growth. This is the first identification of a FASII-like 3-oxoacyl-ACP reductase from a kinetoplastid parasite.
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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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Gurvitz A. A C. elegans model for mitochondrial fatty acid synthase II: the longevity-associated gene W09H1.5/mecr-1 encodes a 2-trans-enoyl-thioester reductase. PLoS One 2009; 4:e7791. [PMID: 19924289 PMCID: PMC2774161 DOI: 10.1371/journal.pone.0007791] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2009] [Accepted: 10/19/2009] [Indexed: 11/19/2022] Open
Abstract
Our recognition of the mitochondria as being important sites of fatty acid biosynthesis is continuously unfolding, especially in light of new data becoming available on compromised fatty acid synthase type 2 (FASII) in mammals. For example, perturbed regulation of murine 17β-HSD8 encoding a component of the mitochondrial FASII enzyme 3-oxoacyl-thioester reductase is implicated in polycystic kidney disease. In addition, over-expression in mice of the Mecr gene coding for 2-trans-enoyl-thioester reductase, also of mitochondrial FASII, leads to impaired heart function. However, mouse knockouts for mitochondrial FASII have hitherto not been reported and, hence, there is a need to develop alternate metazoan models such as nematodes or fruit flies. Here, the identification of Caenorhabditis elegans W09H1.5/MECR-1 as a 2-trans-enoyl-thioester reductase of mitochondrial FASII is reported. To identify MECR-1, Saccharomyces cerevisiae etr1Δ mutant cells were employed that are devoid of mitochondrial 2-trans-enoyl-thioester reductase Etr1p. These yeast mutants fail to synthesize sufficient levels of lipoic acid or form cytochrome complexes, and cannot respire or grow on non-fermentable carbon sources. A mutant yeast strain ectopically expressing nematode mecr-1 was shown to contain reductase activity and resemble the self-complemented mutant strain for these phenotype characteristics. Since MECR-1 was not intentionally targeted for compartmentalization using a yeast mitochondrial leader sequence, this inferred that the protein represented a physiologically functional mitochondrial 2-trans-enoyl-thioester reductase. In accordance with published findings, RNAi-mediated knockdown of mecr-1 in C. elegans resulted in life span extension, presumably due to mitochondrial dysfunction. Moreover, old mecr-1(RNAi) worms had better internal organ appearance and were more mobile than control worms, indicating a reduced physiological age. This is the first report on RNAi work dedicated specifically to curtailing mitochondrial FASII in metazoans. The availability of affected survivors will help to position C. elegans as an excellent model for future pursuits in the emerging field of mitochondrial FASII research.
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Affiliation(s)
- Aner Gurvitz
- Section of Physiology of Lipid Metabolism, Institute of Physiology, Center for Physiology, Pathophysiology and Immunology, Medical University of Vienna, Vienna, Austria.
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Schonauer MS, Kastaniotis AJ, Kursu VAS, Hiltunen JK, Dieckmann CL. Lipoic acid synthesis and attachment in yeast mitochondria. J Biol Chem 2009; 284:23234-42. [PMID: 19570983 DOI: 10.1074/jbc.m109.015594] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Lipoic acid is a sulfur-containing cofactor required for the function of several multienzyme complexes involved in the oxidative decarboxylation of alpha-keto acids and glycine. Mechanistic details of lipoic acid metabolism are unclear in eukaryotes, despite two well defined pathways for synthesis and covalent attachment of lipoic acid in prokaryotes. We report here the involvement of four genes in the synthesis and attachment of lipoic acid in Saccharomyces cerevisiae. LIP2 and LIP5 are required for lipoylation of all three mitochondrial target proteins: Lat1 and Kgd2, the respective E2 subunits of pyruvate dehydrogenase and alpha-ketoglutarate dehydrogenase, and Gcv3, the H protein of the glycine cleavage enzyme. LIP3, which encodes a lipoate-protein ligase homolog, is necessary for lipoylation of Lat1 and Kgd2, and the enzymatic activity of Lip3 is essential for this function. Finally, GCV3, encoding the H protein target of lipoylation, is itself absolutely required for lipoylation of Lat1 and Kgd2. We show that lipoylated Gcv3, and not glycine cleavage activity per se, is responsible for this function. Demonstration that a target of lipoylation is required for lipoylation is a novel result. Through analysis of the role of these genes in protein lipoylation, we conclude that only one pathway for de novo synthesis and attachment of lipoic acid exists in yeast. We propose a model for protein lipoylation in which Lip2, Lip3, Lip5, and Gcv3 function in a complex, which may be regulated by the availability of acetyl-CoA, and which in turn may regulate mitochondrial gene expression.
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Affiliation(s)
- Melissa S Schonauer
- Department of Biochemistry, University of Arizona, Tucson, Arizona 85721, USA
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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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38
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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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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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40
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Heterologous expression of mycobacterial proteins in Saccharomyces cerevisiae reveals two physiologically functional 3-hydroxyacyl-thioester dehydratases, HtdX and HtdY, in addition to HadABC and HtdZ. J Bacteriol 2009; 191:2683-90. [PMID: 19136596 DOI: 10.1128/jb.01046-08] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
We report on Mycobacterium tuberculosis Rv0241c and Rv3389c, representing two physiologically functional 3-hydroxyacyl-thioester dehydratases (Htd). These enzymes are potentially entrained in type 2 fatty acid synthase (FASII). Mycobacterial FASII is involved in the synthesis of mycolic acids, which are the major constituents of the protective layer around the pathogen, shielding it from noxious chemicals and the host's immune system. Mycolic acids are additionally associated with the virulence and resilience of M. tuberculosis. Here, Rv0241c and Rv3389c, which are distinct from the previously identified heterodimers Rv0635-Rv0636 (HadAB) and Rv0636-Rv0637 (HadBC) but also the homodimer Rv0130 (HtdZ), were identified by expressing the corresponding candidate open reading frames in Saccharomyces cerevisiae htd2Delta cells lacking mitochondrial 3-hydroxyacyl-acyl carrier protein dehydratase activity, followed by scoring for phenotype rescue. The htd2Delta mutant fails to produce sufficient levels of lipoic acid and does not respire or grow on nonfermentable carbon sources. Soluble protein extracts made from mutant htd2Delta cells expressing mitochondrially targeted Rv0241c or Rv3389c contained 3-hydroxyacyl-thioester hydratase activity. Moreover, mutant yeast cells expressing Rv0241c or Rv3389c were able to recover their respiratory growth on glycerol medium and efficiently reduce 2,3,5-triphenyltetrazolium chloride. Additionally, expression of mitochondrial Rv0241c or Rv3389c in htd2Delta cells also restored de novo lipoic acid synthesis to 92 and 40% of the level in the wild-type strain, respectively. We propose naming Rv0241c and Rv3389c as HtdX and HtdY, respectively, and discuss the implications of our finding with reference to Rv0098, a candidate mycobacterial FabZ homologue with intrinsic thioesterase and hydratase activities that lacks the eukaryotic-like hydratase-2 motif.
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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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42
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Intersection of RNA processing and the type II fatty acid synthesis pathway in yeast mitochondria. Mol Cell Biol 2008; 28:6646-57. [PMID: 18779316 DOI: 10.1128/mcb.01162-08] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Distinct metabolic pathways can intersect in ways that allow hierarchical or reciprocal regulation. In a screen of respiration-deficient Saccharomyces cerevisiae gene deletion strains for defects in mitochondrial RNA processing, we found that lack of any enzyme in the mitochondrial fatty acid type II biosynthetic pathway (FAS II) led to inefficient 5' processing of mitochondrial precursor tRNAs by RNase P. In particular, the precursor containing both RNase P RNA (RPM1) and tRNA(Pro) accumulated dramatically. Subsequent Pet127-driven 5' processing of RPM1 was blocked. The FAS II pathway defects resulted in the loss of lipoic acid attachment to subunits of three key mitochondrial enzymes, which suggests that the octanoic acid produced by the pathway is the sole precursor for lipoic acid synthesis and attachment. The protein component of yeast mitochondrial RNase P, Rpm2, is not modified by lipoic acid in the wild-type strain, and it is imported in FAS II mutant strains. Thus, a product of the FAS II pathway is required for RNase P RNA maturation, which positively affects RNase P activity. In addition, a product is required for lipoic acid production, which is needed for the activity of pyruvate dehydrogenase, which feeds acetyl-coenzyme A into the FAS II pathway. These two positive feedback cycles may provide switch-like control of mitochondrial gene expression in response to the metabolic state of the cell.
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Function of heterologous Mycobacterium tuberculosis InhA, a type 2 fatty acid synthase enzyme involved in extending C20 fatty acids to C60-to-C90 mycolic acids, during de novo lipoic acid synthesis in Saccharomyces cerevisiae. Appl Environ Microbiol 2008; 74:5078-85. [PMID: 18552191 DOI: 10.1128/aem.00655-08] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We describe the physiological function of heterologously expressed Mycobacterium tuberculosis InhA during de novo lipoic acid synthesis in yeast (Saccharomyces cerevisiae) mitochondria. InhA, representing 2-trans-enoyl-acyl carrier protein reductase and the target for the front-line antituberculous drug isoniazid, is involved in the activity of dissociative type 2 fatty acid synthase (FASII) that extends associative type 1 fatty acid synthase (FASI)-derived C(20) fatty acids to form C(60)-to-C(90) mycolic acids. Mycolic acids are major constituents of the protective layer around the pathogen that contribute to virulence and resistance to certain antimicrobials. Unlike FASI, FASII is thought to be incapable of de novo biosynthesis of fatty acids. Here, the genes for InhA (Rv1484) and four similar proteins (Rv0927c, Rv3485c, Rv3530c, and Rv3559c) were expressed in S. cerevisiae etr1Delta cells lacking mitochondrial 2-trans-enoyl-thioester reductase activity. The phenotype of the yeast mutants includes the inability to produce sufficient levels of lipoic acid, form mitochondrial cytochromes, respire, or grow on nonfermentable carbon sources. Yeast etr1Delta cells expressing mitochondrial InhA were able to respire, grow on glycerol, and produce lipoic acid. Commensurate with a role in mitochondrial de novo fatty acid biosynthesis, InhA could accept in vivo much shorter acyl-thioesters (C(4) to C(8)) than was previously thought (>C(12)). Moreover, InhA functioned in the absence of AcpM or protein-protein interactions with its native FASII partners KasA, KasB, FabD, and FabH. None of the four proteins similar to InhA complemented the yeast mutant phenotype. We discuss the implications of our findings with reference to lipoic acid synthesis in M. tuberculosis and the potential use of yeast FASII mutants for investigating the physiological function of drug-targeted pathogen enzymes involved in fatty acid biosynthesis.
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Chen ZJ, Pudas R, Sharma S, Smart OS, Juffer AH, Hiltunen JK, Wierenga RK, Haapalainen AM. Structural enzymological studies of 2-enoyl thioester reductase of the human mitochondrial FAS II pathway: new insights into its substrate recognition properties. J Mol Biol 2008; 379:830-44. [PMID: 18479707 DOI: 10.1016/j.jmb.2008.04.041] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2008] [Revised: 04/15/2008] [Accepted: 04/16/2008] [Indexed: 11/19/2022]
Abstract
Structural and kinetic properties of the human 2-enoyl thioester reductase [mitochondrial enoyl-coenzyme A reductase (MECR)/ETR1] of the mitochondrial fatty acid synthesis (FAS) II pathway have been determined. The crystal structure of this dimeric enzyme (at 2.4 A resolution) suggests that the binding site for the recognition helix of the acyl carrier protein is in a groove between the two adjacent monomers. This groove is connected via the pantetheine binding cleft to the active site. The modeled mode of NADPH binding, using molecular dynamics calculations, suggests that Tyr94 and Trp311 are critical for catalysis, which is supported by enzyme kinetic data. A deep, water-filled pocket, shaped by hydrophobic and polar residues and extending away from the catalytic site, was recognized. This pocket can accommodate a fatty acyl tail of up to 16 carbons. Mutagenesis of the residues near the end of this pocket confirms the importance of this region for the binding of substrate molecules with long fatty acyl tails. Furthermore, the kinetic analysis of the wild-type MECR/ETR1 shows a bimodal distribution of catalytic efficiencies, in agreement with the notion that two major products are generated by the mitochondrial FAS II pathway.
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MESH Headings
- Acyl Carrier Protein/metabolism
- Amino Acid Sequence
- Binding Sites
- Catalytic Domain
- Crystallography, X-Ray
- Dimerization
- Fatty Acid Synthase, Type I/chemistry
- Fatty Acid Synthase, Type I/genetics
- Fatty Acid Synthase, Type I/metabolism
- Humans
- Kinetics
- Mitochondria/enzymology
- Models, Molecular
- Molecular Sequence Data
- Mutagenesis, Site-Directed
- NADH, NADPH Oxidoreductases/chemistry
- NADH, NADPH Oxidoreductases/genetics
- NADH, NADPH Oxidoreductases/metabolism
- NADP/metabolism
- Oxidoreductases Acting on CH-CH Group Donors
- Protein Conformation
- Protein Structure, Quaternary
- Recombinant Proteins/chemistry
- Recombinant Proteins/genetics
- Recombinant Proteins/metabolism
- Sequence Homology, Amino Acid
- Substrate Specificity
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Affiliation(s)
- Zhi-Jun Chen
- Biocenter Oulu and Department of Biochemistry, University of Oulu, P.O. Box 3000, FI-90014, Oulu, Finland
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Identification of a novel mycobacterial 3-hydroxyacyl-thioester dehydratase, HtdZ (Rv0130), by functional complementation in yeast. J Bacteriol 2008; 190:4088-90. [PMID: 18375556 DOI: 10.1128/jb.00016-08] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We report on the identification of Mycobacterium tuberculosis HtdZ (Rv0130), representing a novel 3-hydroxyacyl-thioester dehydratase. HtdZ was picked up by the functional complementation of Saccharomyces cerevisiae htd2Delta cells lacking the dehydratase of mitochondrial type II fatty acid synthase. Mutant cells expressing HtdZ contained dehydratase activity, recovered their respiratory ability, and partially restored de novo lipoic acid synthesis.
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46
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The 3-hydroxyacyl-ACP dehydratase of mitochondrial fatty acid synthesis inTrypanosoma brucei. FEBS Lett 2008; 582:729-33. [DOI: 10.1016/j.febslet.2008.01.051] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2008] [Accepted: 01/28/2008] [Indexed: 11/22/2022]
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