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Zhang M, Cai F, Guo J, Liu S, Ma G, Cai M, Zhang R, Deng J. ACAT2 suppresses the ubiquitination of YAP1 to enhance the proliferation and metastasis ability of gastric cancer via the upregulation of SETD7. Cell Death Dis 2024; 15:297. [PMID: 38670954 PMCID: PMC11053133 DOI: 10.1038/s41419-024-06666-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Revised: 04/06/2024] [Accepted: 04/10/2024] [Indexed: 04/28/2024]
Abstract
The contributions of aberrantly expressed metabolic enzymes to gastric cancer (GC) initiation and progression have been widely appreciated in recent years. Acetyl-CoA acetyltransferase 2 (ACAT2) is one member of the acetyl- CoA thiolase family. Previous studies demonstrated that ACAT2 either promotes or suppresses tumor progression in different conditions. However, the function and mechanisms of ACAT2 in GC remain unknown. We found that the expression of this enzyme was significantly increased in GC tissues compared with normal counterparts, which prompted us to further investigate the roles of this protein in GC biology. In vitro functional studies showed that ACAT2 knockdown markedly halted the proliferation and the motility of GC cells; these functions favoring malignant phenotypes of GC cells were further validated in animal experiments. Mechanistically, ACAT2 depletion significantly reduced the transcription of SETD7, which is a histone methyltransferase and plays critical roles in GC cells. We found that the pro-tumoral functions of ACAT2 were largely dependent on SETD7. Moreover, SETD7 decreased the ubiquitination level of Yes-associated protein 1 (YAP1), thereby protecting YAP1 from proteasome degradation. Increased YAP1 protein expression remarkably activated the YAP1/TAZ-TEAD1 signaling pathway, which further boosted the malignant phenotypes in GC cells. In conclusion, these findings highlight the pro-tumoral functions and molecular underpinnings of ACAT2 in GC cells, and suggest that ACAT2 could be a promising target in GC treatment.
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Affiliation(s)
- Mengmeng Zhang
- Department of Gastric Surgery, Tianjin Medical University Cancer Institute & Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin, Tianjin Key Laboratory of Digestive Cancer, Tianjin's Clinical Research Center for Cancer, Tianjin, 300060, PR China
| | - Fenglin Cai
- Department of Biochemistry and Molecular Biology, The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, 300060, PR China
| | - Jiamei Guo
- Department of Gastric Surgery, Tianjin Medical University Cancer Institute & Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin, Tianjin Key Laboratory of Digestive Cancer, Tianjin's Clinical Research Center for Cancer, Tianjin, 300060, PR China
| | - Siya Liu
- Department of Gastric Surgery, Tianjin Medical University Cancer Institute & Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin, Tianjin Key Laboratory of Digestive Cancer, Tianjin's Clinical Research Center for Cancer, Tianjin, 300060, PR China
| | - Gang Ma
- Department of Gastric Surgery, Tianjin Medical University Cancer Institute & Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin, Tianjin Key Laboratory of Digestive Cancer, Tianjin's Clinical Research Center for Cancer, Tianjin, 300060, PR China
| | - Mingzhi Cai
- Department of Gastric Surgery, Tianjin Medical University Cancer Institute & Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin, Tianjin Key Laboratory of Digestive Cancer, Tianjin's Clinical Research Center for Cancer, Tianjin, 300060, PR China
| | - Rupeng Zhang
- Department of Gastric Surgery, Tianjin Medical University Cancer Institute & Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin, Tianjin Key Laboratory of Digestive Cancer, Tianjin's Clinical Research Center for Cancer, Tianjin, 300060, PR China
| | - Jingyu Deng
- Department of Gastric Surgery, Tianjin Medical University Cancer Institute & Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin, Tianjin Key Laboratory of Digestive Cancer, Tianjin's Clinical Research Center for Cancer, Tianjin, 300060, PR China.
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2
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Cholico GN, Orlowska K, Fling RR, Sink WJ, Zacharewski NA, Fader KA, Nault R, Zacharewski T. Consequences of reprogramming acetyl-CoA metabolism by 2,3,7,8-tetrachlorodibenzo-p-dioxin in the mouse liver. Sci Rep 2023; 13:4138. [PMID: 36914879 PMCID: PMC10011583 DOI: 10.1038/s41598-023-31087-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 03/06/2023] [Indexed: 03/14/2023] Open
Abstract
2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a persistent environmental contaminant that induces the progression of steatosis to steatohepatitis with fibrosis in mice. Furthermore, TCDD reprograms hepatic metabolism by redirecting glycolytic intermediates while inhibiting lipid metabolism. Here, we examined the effect of TCDD on hepatic acetyl-coenzyme A (acetyl-CoA) and β-hydroxybutyrate levels as well as protein acetylation and β-hydroxybutyrylation. Acetyl-CoA is not only a central metabolite in multiple anabolic and catabolic pathways, but also a substrate used for posttranslational modification of proteins and a surrogate indicator of cellular energy status. Targeted metabolomic analysis revealed a dose-dependent decrease in hepatic acetyl-CoA levels coincident with the phosphorylation of pyruvate dehydrogenase (E1), and the induction of pyruvate dehydrogenase kinase 4 and pyruvate dehydrogenase phosphatase, while repressing ATP citrate lyase and short-chain acyl-CoA synthetase gene expression. In addition, TCDD dose-dependently reduced the levels of hepatic β-hydroxybutyrate and repressed ketone body biosynthesis gene expression. Moreover, levels of total hepatic protein acetylation and β-hydroxybutyrylation were reduced. AMPK phosphorylation was induced consistent with acetyl-CoA serving as a cellular energy status surrogate, yet subsequent targets associated with re-establishing energy homeostasis were not activated. Collectively, TCDD reduced hepatic acetyl-CoA and β-hydroxybutyrate levels eliciting starvation-like conditions despite normal levels of food intake.
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Affiliation(s)
- Giovan N Cholico
- Biochemistry and Molecular Biology, Michigan State University, Biochemistry Building, 603 Wilson Road, East Lansing, MI, 48824, USA
- Institute for Integrative Toxicology, Michigan State University, East Lansing, MI, 48824, USA
| | - Karina Orlowska
- Biochemistry and Molecular Biology, Michigan State University, Biochemistry Building, 603 Wilson Road, East Lansing, MI, 48824, USA
- Institute for Integrative Toxicology, Michigan State University, East Lansing, MI, 48824, USA
| | - Russell R Fling
- Institute for Integrative Toxicology, Michigan State University, East Lansing, MI, 48824, USA
- Microbiology & Molecular Genetics, Michigan State University, East Lansing, MI, 48824, USA
| | - Warren J Sink
- Biochemistry and Molecular Biology, Michigan State University, Biochemistry Building, 603 Wilson Road, East Lansing, MI, 48824, USA
- Institute for Integrative Toxicology, Michigan State University, East Lansing, MI, 48824, USA
| | - Nicholas A Zacharewski
- Biochemistry and Molecular Biology, Michigan State University, Biochemistry Building, 603 Wilson Road, East Lansing, MI, 48824, USA
| | - Kelly A Fader
- Biochemistry and Molecular Biology, Michigan State University, Biochemistry Building, 603 Wilson Road, East Lansing, MI, 48824, USA
- Institute for Integrative Toxicology, Michigan State University, East Lansing, MI, 48824, USA
| | - Rance Nault
- Biochemistry and Molecular Biology, Michigan State University, Biochemistry Building, 603 Wilson Road, East Lansing, MI, 48824, USA
- Institute for Integrative Toxicology, Michigan State University, East Lansing, MI, 48824, USA
| | - Tim Zacharewski
- Biochemistry and Molecular Biology, Michigan State University, Biochemistry Building, 603 Wilson Road, East Lansing, MI, 48824, USA.
- Institute for Integrative Toxicology, Michigan State University, East Lansing, MI, 48824, USA.
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3
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Vrzoňová R, Tóth R, Siváková B, Moťovská A, Gaplovská-Kyselá K, Baráth P, Tomáška Ľ, Gácser A, Gabaldón T, Nosek J, Neboháčová M. OCT1 - a yeast mitochondrial thiolase involved in the 3-oxoadipate pathway. FEMS Yeast Res 2021; 21:6293844. [PMID: 34089318 DOI: 10.1093/femsyr/foab034] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Accepted: 06/03/2021] [Indexed: 11/13/2022] Open
Abstract
The 3-oxoacyl-CoA thiolases catalyze the last step of the fatty acid β-oxidation pathway. In yeasts and plants, this pathway takes place exclusively in peroxisomes, whereas in animals it occurs in both peroxisomes and mitochondria. In contrast to baker's yeast Saccharomyces cerevisiae, yeast species from the Debaryomycetaceae family also encode a thiolase with predicted mitochondrial localization. These yeasts are able to utilize a range of hydroxyaromatic compounds via the 3-oxoadipate pathway the last step of which is catalyzed by 3-oxoadipyl-CoA thiolase and presumably occurs in mitochondria. In this work, we studied Oct1p, an ortholog of this enzyme from Candida parapsilosis. We found that the cells grown on a 3-oxoadipate pathway substrate exhibit increased levels of the OCT1 mRNA. Deletion of both OCT1 alleles impairs the growth of C. parapsilosis cells on 3-oxoadipate pathway substrates and this defect can be rescued by expression of the OCT1 gene from a plasmid vector. Subcellular localization experiments and LC-MS/MS analysis of enriched organellar fraction-proteins confirmed the presence of Oct1p in mitochondria. Phylogenetic profiling of Oct1p revealed an intricate evolutionary pattern indicating multiple horizontal gene transfers among different fungal groups.
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Affiliation(s)
- Romana Vrzoňová
- Faculty of Natural Sciences, Department of Biochemistry, Comenius University in Bratislava, Ilkovičova 6, 84215 Bratislava, Slovakia
| | - Renáta Tóth
- Department of Microbiology, University of Szeged, Közép fasor 52, H-6726 Szeged, Hungary.,MTA-SZTE Lendület Mycobiome Research Group, University of Szeged, Szeged, Hungary
| | - Barbara Siváková
- Institute of Chemistry, Slovak Academy of Sciences, Dúbravská cesta 9, 84538 Bratislava, Slovakia
| | - Anna Moťovská
- Faculty of Natural Sciences, Department of Biochemistry, Comenius University in Bratislava, Ilkovičova 6, 84215 Bratislava, Slovakia
| | - Katarína Gaplovská-Kyselá
- Faculty of Natural Sciences, Department of Genetics, Comenius University in Bratislava, Ilkovičova 6, 84215 Bratislava, Slovakia
| | - Peter Baráth
- Institute of Chemistry, Slovak Academy of Sciences, Dúbravská cesta 9, 84538 Bratislava, Slovakia
| | - Ľubomír Tomáška
- Faculty of Natural Sciences, Department of Genetics, Comenius University in Bratislava, Ilkovičova 6, 84215 Bratislava, Slovakia
| | - Attila Gácser
- Department of Microbiology, University of Szeged, Közép fasor 52, H-6726 Szeged, Hungary.,MTA-SZTE Lendület Mycobiome Research Group, University of Szeged, Szeged, Hungary
| | - Toni Gabaldón
- Institute for Research in Biomedicine (IRB), Jordi Girona 29, 08034 Barcelona, Spain.,Barcelona Supercomputing Centre (BSC-CNS), Jordi Girona 29, 08034 Barcelona, Spain.,Catalan Institution for Research and Advanced Studies (ICREA), Barcelona, Spain
| | - Jozef Nosek
- Faculty of Natural Sciences, Department of Biochemistry, Comenius University in Bratislava, Ilkovičova 6, 84215 Bratislava, Slovakia
| | - Martina Neboháčová
- Faculty of Natural Sciences, Department of Biochemistry, Comenius University in Bratislava, Ilkovičova 6, 84215 Bratislava, Slovakia
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4
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Ago Y, Otsuka H, Sasai H, Abdelkreem E, Nakama M, Aoyama Y, Matsumoto H, Fujiki R, Ohara O, Akiyama K, Fukui K, Watanabe Y, Nakajima Y, Ohnishi H, Ito T, Fukao T. Japanese patients with mitochondrial 3-hydroxy-3-methylglutaryl-CoA synthase deficiency: In vitro functional analysis of five novel HMGCS2 mutations. Exp Ther Med 2020; 20:39. [PMID: 32952630 PMCID: PMC7480138 DOI: 10.3892/etm.2020.9166] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Accepted: 06/17/2020] [Indexed: 02/05/2023] Open
Abstract
Mitochondrial 3-hydroxy-3-methylglutaryl-CoA synthase (HMGCS2) deficiency is a metabolic disorder caused by mutations in the HMGCS2 gene. The present study describes the identification of four cases of HMGCS2 deficiency in Japan. Hepatomegaly and severe metabolic acidosis were observed in all cases. Fatty liver was identified in three cases, which suggested the unavailability of fatty acids. All patients presented with a high C2/C0 ratio, suggesting that the fatty acid oxidation pathway was normal during metabolic crisis. Genetic analyses revealed five rare, novel variants (p.G219E, p.M235T, p.V253A, p.S392L and p.R500C) in HMGCS2. To confirm their pathogenicity, a eukaryotic expression system and a bacterial expression system was adopted that was successfully used to obtain affinity-purified HMGCS2 protein with measurable activity. Purified M235T, S392L and R500C proteins did not retain any residual activity, whilst the V253A variant showed some residual enzymatic activity. Judging from the transient expression experiment in 293T cells, the G219E variant appeared to be unstable. In conclusion, the present study identified five novel variants of HMGCS2 that were indicated to be pathogenic in four patients affected by HMGCS2 deficiency.
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Affiliation(s)
- Yasuhiko Ago
- Department of Pediatrics, Graduate School of Medicine, Gifu University Hospital, Gifu, Gifu 501-1194, Japan
| | - Hiroki Otsuka
- Department of Pediatrics, Graduate School of Medicine, Gifu University Hospital, Gifu, Gifu 501-1194, Japan
| | - Hideo Sasai
- Department of Pediatrics, Graduate School of Medicine, Gifu University Hospital, Gifu, Gifu 501-1194, Japan.,Clinical Genetics Center, Gifu University Hospital, Gifu, Gifu 501-1194, Japan
| | - Elsayed Abdelkreem
- Department of Pediatrics, Faculty of Medicine, Sohag University, Sohag 82524, Egypt
| | - Mina Nakama
- Department of Pediatrics, Graduate School of Medicine, Gifu University Hospital, Gifu, Gifu 501-1194, Japan.,Clinical Genetics Center, Gifu University Hospital, Gifu, Gifu 501-1194, Japan
| | - Yuka Aoyama
- Department of Biomedical Sciences, College of Life and Health Sciences, Education and Training Center of Medical Technology, Chubu University, Kasugai, Aichi 487-8501, Japan
| | - Hideki Matsumoto
- Department of Pediatrics, Graduate School of Medicine, Gifu University Hospital, Gifu, Gifu 501-1194, Japan
| | - Ryoji Fujiki
- Department of Applied Genomics, Kazusa DNA Research Institute, Kisarazu, Chiba 292-0818, Japan
| | - Osamu Ohara
- Department of Applied Genomics, Kazusa DNA Research Institute, Kisarazu, Chiba 292-0818, Japan
| | | | - Kaori Fukui
- Department of Pediatrics and Child Health, Kurume University School of Medicine, Kurume, Fukuoka 830-0011, Japan
| | - Yoriko Watanabe
- Department of Pediatrics and Child Health, Kurume University School of Medicine, Kurume, Fukuoka 830-0011, Japan.,Research Institute of Medical Mass Spectrometry, Kurume University School of Medicine, Kurume, Fukuoka 830-0011, Japan
| | - Yoko Nakajima
- Department of Pediatrics, Fujita Health University School of Medicine, Toyoake, Aichi 470-1192, Japan
| | - Hidenori Ohnishi
- Department of Pediatrics, Graduate School of Medicine, Gifu University Hospital, Gifu, Gifu 501-1194, Japan
| | - Tetsuya Ito
- Department of Pediatrics, Fujita Health University School of Medicine, Toyoake, Aichi 470-1192, Japan
| | - Toshiyuki Fukao
- Department of Pediatrics, Graduate School of Medicine, Gifu University Hospital, Gifu, Gifu 501-1194, Japan.,Clinical Genetics Center, Gifu University Hospital, Gifu, Gifu 501-1194, Japan
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5
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Abdelkreem E, Harijan RK, Yamaguchi S, Wierenga RK, Fukao T. Mutation update on ACAT1 variants associated with mitochondrial acetoacetyl-CoA thiolase (T2) deficiency. Hum Mutat 2019; 40:1641-1663. [PMID: 31268215 PMCID: PMC6790690 DOI: 10.1002/humu.23831] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2019] [Revised: 05/27/2019] [Accepted: 05/31/2019] [Indexed: 02/05/2023]
Abstract
Mitochondrial acetoacetyl‐CoA thiolase (T2, encoded by the ACAT1 gene) deficiency is an inherited disorder of ketone body and isoleucine metabolism. It typically manifests with episodic ketoacidosis. The presence of isoleucine‐derived metabolites is the key marker for biochemical diagnosis. To date, 105 ACAT1 variants have been reported in 149 T2‐deficient patients. The 56 disease‐associated missense ACAT1 variants have been mapped onto the crystal structure of T2. Almost all these missense variants concern residues that are completely or partially buried in the T2 structure. Such variants are expected to cause T2 deficiency by having lower in vivo T2 activity because of lower folding efficiency and/or stability. Expression and activity data of 30 disease‐associated missense ACAT1 variants have been measured by expressing them in human SV40‐transformed fibroblasts. Only two variants (p.Cys126Ser and p.Tyr219His) appear to have equal stability as wild‐type. For these variants, which are inactive, the side chains point into the active site. In patients with T2 deficiency, the genotype does not correlate with the clinical phenotype but exerts a considerable effect on the biochemical phenotype. This could be related to variable remaining residual T2 activity in vivo and has important clinical implications concerning disease management and newborn screening.
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Affiliation(s)
- Elsayed Abdelkreem
- Department of Pediatrics, Graduate School of Medicine, Gifu University, Gifu, Japan.,Department of Pediatrics, Faculty of Medicine, Sohag University, Sohag, Egypt
| | - Rajesh K Harijan
- Department of Biochemistry, Albert Einstein College of Medicine, New York, New York
| | - Seiji Yamaguchi
- Department of Pediatrics, Shimane University School of Medicine, Izumo, Japan
| | | | - Toshiyuki Fukao
- Department of Pediatrics, Graduate School of Medicine, Gifu University, Gifu, Japan
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6
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Sasai H, Aoyama Y, Otsuka H, Abdelkreem E, Naiki Y, Kubota M, Sekine Y, Itoh M, Nakama M, Ohnishi H, Fujiki R, Ohara O, Fukao T. Heterozygous carriers of succinyl-CoA:3-oxoacid CoA transferase deficiency can develop severe ketoacidosis. J Inherit Metab Dis 2017; 40:845-852. [PMID: 28695376 DOI: 10.1007/s10545-017-0065-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Revised: 06/07/2017] [Accepted: 06/08/2017] [Indexed: 02/05/2023]
Abstract
Succinyl-CoA:3-oxoacid CoA transferase (SCOT, gene symbol OXCT1) deficiency is an autosomal recessive disorder in ketone body utilization that results in severe recurrent ketoacidotic episodes in infancy, including neonatal periods. More than 30 patients with this disorder have been reported and to our knowledge, their heterozygous parents and siblings have had no apparent ketoacidotic episodes. Over 5 years (2008-2012), we investigated several patients that presented with severe ketoacidosis and identified a heterozygous OXCT1 mutation in four of these cases (Case1 p.R281C, Case2 p.T435N, Case3 p.W213*, Case4 c.493delG). To confirm their heterozygous state, we performed a multiplex ligation-dependent probe amplification analysis on the OXCT1 gene which excluded the presence of large deletions or insertions in another allele. A sequencing analysis of subcloned full-length SCOT cDNA showed that wild-type cDNA clones were present at reasonable rates to mutant cDNA clones. Over the following 2 years (2013-2014), we analyzed OXCT1 mutations in six more patients presenting with severe ketoacidosis (blood pH ≦7.25 and total ketone body ≧10 mmol/L) with non-specific urinary organic acid profiles. Of these, a heterozygous OXCT1 mutation was found in two cases (Case5 p.G391D, Case6 p.R281C). Moreover, transient expression analysis revealed R281C and T435N mutants to be temperature-sensitive. This characteristic may be important because most patients developed ketoacidosis during infections. Our data indicate that heterozygous carriers of OXCT1 mutations can develop severe ketoacidotic episodes in conjunction with ketogenic stresses.
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Affiliation(s)
- Hideo Sasai
- Department of Pediatrics, Graduate School of Medicine, Gifu University, 1-1 Yanagido, Gifu City, Gifu, 501-1194, Japan
| | - Yuka Aoyama
- Department of Pediatrics, Graduate School of Medicine, Gifu University, 1-1 Yanagido, Gifu City, Gifu, 501-1194, Japan
- Department of Biomedical Sciences, College of Life and Health Sciences, Chubu University, Kasugai, Japan
| | - Hiroki Otsuka
- Department of Pediatrics, Graduate School of Medicine, Gifu University, 1-1 Yanagido, Gifu City, Gifu, 501-1194, Japan
| | - Elsayed Abdelkreem
- Department of Pediatrics, Graduate School of Medicine, Gifu University, 1-1 Yanagido, Gifu City, Gifu, 501-1194, Japan
- Department of Pediatrics, Faculty of Medicine, Sohag University, Sohag, Egypt
| | - Yasuhiro Naiki
- Division of Endocrinology and Metabolism, National Center for Child Health and Development, Tokyo, Japan
| | - Mitsuru Kubota
- Department of General Pediatrics and Interdisciplinary Medicine, National Center for Child Health and Development, Tokyo, Japan
| | - Yuji Sekine
- Department of General Pediatrics, Shizuoka Children's Hospital, Shizuoka, Japan
| | - Masatsune Itoh
- Department of Pediatrics, Kanazawa Medical University, Kanazawa, Japan
| | - Mina Nakama
- Division of Clinical Genetics, Gifu University Hospital, Gifu, Japan
| | - Hidenori Ohnishi
- Department of Pediatrics, Graduate School of Medicine, Gifu University, 1-1 Yanagido, Gifu City, Gifu, 501-1194, Japan
| | - Ryoji Fujiki
- Department of Technology Development, Kazusa DNA Research Institute, Kisarazu, Japan
| | - Osamu Ohara
- Department of Technology Development, Kazusa DNA Research Institute, Kisarazu, Japan
| | - Toshiyuki Fukao
- Department of Pediatrics, Graduate School of Medicine, Gifu University, 1-1 Yanagido, Gifu City, Gifu, 501-1194, Japan.
- Division of Clinical Genetics, Gifu University Hospital, Gifu, Japan.
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7
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Nakao N, Kaneda H, Tsushima N, Tanaka M. Characterization of primary structure and post-hatching increase in chicken cytosolic acetoacetyl-coA thiolase in the liver. Poult Sci 2016; 95:1406-10. [PMID: 26944984 DOI: 10.3382/ps/pew045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2015] [Accepted: 12/03/2015] [Indexed: 11/20/2022] Open
Abstract
Acetoacetyl-CoA thiolase (EC 2.3.1.9) catalyzes the cleavage of acetoacetyl-CoA into acetyl-CoA and its reverse reaction, the synthesis of acetoacetyl-CoA. Cytosolic acetoacetyl-CoA thiolase ( CT: ) is a key enzyme in the initial step of the cholesterol synthesis pathway. In the present study, we characterized the amino acid sequence of chicken CT and the tissue distribution of its mRNA and protein, together with their developmental changes in the liver. The amino acid sequence encoded by the nucleotide sequence of chicken CT cDNA showed a higher overall identity with those of human (74.3%) and rat (74.6%) CTs. Amino acid residues known to participate in enzymatic activity in human CT are conserved in chicken CT. Real-time PCR analysis revealed the expression of CT mRNA in the liver, kidney, adrenal gland, jejunum and ovary of adult hens, with higher levels in the liver, kidney, adrenal gland and ovary. Western blot analysis detected an immunoreactive protein of 41 kDa from cytoplasmic fraction but not particulate fractions of adult chicken liver. The immunoreactive protein was detected in all the tissues. The mRNA levels in the liver rapidly increased after hatching, with a maximum on d 5 post-hatching, after which they gradually decreased to adult levels. A similar change was observed in the protein levels. The increase in transcription and protein synthesis of CT suggests that the synthetic pathway of cholesterol from acetyl-CoA produced by CT replaces the hydrolysis of accumulated cholesteryl ester in the liver, in response to a change in the nutrient source from the lipid-rich yolk to a lower-lipid diet during the early post-hatching period.
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Affiliation(s)
- N Nakao
- Laboratory of Animal Physiology, Department of Animal Science, Faculty of Applied Life Science, Nippon Veterinary and Life Science University, 1-7-1 Kyonancho, Musashino, Tokyo, 180-8602, Japan
| | - H Kaneda
- Laboratory of Animal Physiology, Department of Animal Science, Faculty of Applied Life Science, Nippon Veterinary and Life Science University, 1-7-1 Kyonancho, Musashino, Tokyo, 180-8602, Japan
| | - N Tsushima
- Laboratory of Animal Physiology, Department of Animal Science, Faculty of Applied Life Science, Nippon Veterinary and Life Science University, 1-7-1 Kyonancho, Musashino, Tokyo, 180-8602, Japan
| | - M Tanaka
- Laboratory of Animal Physiology, Department of Animal Science, Faculty of Applied Life Science, Nippon Veterinary and Life Science University, 1-7-1 Kyonancho, Musashino, Tokyo, 180-8602, Japan
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8
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Fukao T, Sass JO, Kursula P, Thimm E, Wendel U, Ficicioglu C, Monastiri K, Guffon N, Barić I, Zabot MT, Kondo N. Clinical and molecular characterization of five patients with succinyl-CoA:3-ketoacid CoA transferase (SCOT) deficiency. Biochim Biophys Acta Mol Basis Dis 2011; 1812:619-24. [PMID: 21296660 DOI: 10.1016/j.bbadis.2011.01.015] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2010] [Revised: 01/26/2011] [Accepted: 01/28/2011] [Indexed: 11/21/2022]
Abstract
Succinyl-CoA:3-ketoacid CoA transferase (SCOT) deficiency is an inborn error of ketone body metabolism and causes episodic ketoacidosis. We report clinical and molecular analyses of 5 patients with SCOT deficiency. Patients GS07, GS13, and GS14 are homozygotes of S405P, L327P, and R468C, respectively. GS17 and GS18 are compound heterozygotes for S226N and A215V, and V404F and E273X, respectively. These mutations have not been reported previously. Missense mutations were further characterized by transient expression analysis of mutant cDNAs. Among 6 missense mutations, mutants L327P, R468C, and A215V retained some residual activities and their mutant proteins were detected in immunoblot analysis following expression at 37°C. They were more stable at 30°C than 37°C, indicating their temperature sensitive character. The R468C mutant is a distinct temperature sensitive mutant which retained 12% and 51% of wild-type residual activities at 37 and 30°C, respectively. The S226N mutant protein was detected but retained no residual activity. Effects of missense mutations were predicted from the tertiary structure of the SCOT molecule. Main effects of these mutations were destabilization of SCOT molecules, and some of them also affected catalytic activity. Among 5 patients, GS07 and GS18 had null mutations in both alleles and the other three patients retained some residual SCOT activities. All 5 developed a first severe ketoacidotic crisis with blood gas pH <7.1, and experienced multiple ketoacidotic decompensations (two of them had seven such episodes). In general, the outcome was good even following multiple ketoacidotic events. Permanent ketosis or ketonuria is considered a pathognomonic feature of SCOT deficiency. However, this condition depends not only on residual activity but also on environmental factors.
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Fukao T, Ishii T, Amano N, Kursula P, Takayanagi M, Murase K, Sakaguchi N, Kondo N, Hasegawa T. A neonatal-onset succinyl-CoA:3-ketoacid CoA transferase (SCOT)-deficient patient with T435N and c.658-666dupAACGTGATT p.N220_I222dup mutations in the OXCT1 gene. J Inherit Metab Dis 2010; 33 Suppl 3:S307-13. [PMID: 20652411 DOI: 10.1007/s10545-010-9168-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2010] [Revised: 06/30/2010] [Accepted: 07/02/2010] [Indexed: 12/12/2022]
Abstract
Succinyl-CoA:3-ketoacid CoA transferase (SCOT) deficiency causes episodic ketoacidotic crises and no apparent symptoms between them. Here, we report a Japanese case of neonatal-onset SCOT deficiency. The male patient presented a severe ketoacidotic crisis, with blood pH of 7.072 and bicarbonate of 5.8 mmol/L at the age of 2 days and was successfully treated with intravenous infusion of glucose and sodium bicarbonate. He was diagnosed as SCOT deficient by enzymatic assay and mutation analysis. At the age of 7 months, he developed a second ketoacidotic crisis, with blood pH of 7.059, bicarbonate of 5.4 mmol/L, and total ketone bodies of 29.1 mmol/L. He experienced two milder ketoacidotic crises at the ages of 1 year and 7 months and 3 years and 7 months. His urinary ketone bodies usually range from negative to 1+ but sometimes show 3+ (ketostix) without any symptoms. Hence, this patient does not show permanent ketonuria, which is characteristic of typical SCOT-deficient patients. He is a compound heterozygote of c.1304C > A (T435N) and c.658-666dupAACGTGATT p.N220_I222dup. mutations in the OXCT1 gene. The T435N mutation was previously reported as one which retained significant residual activity. The latter novel mutation was revealed to retain no residual activity by transient expression analysis. Both T435N and N220_I222 lie close to the SCOT dimerization interface and are not directly connected to the active site in the tertiary structure of a human SCOT dimer. In transient expression analysis, no apparent interallelic complementation or dominant negative effects were observed. Significant residual activity from the T435N mutant allele may prevent the patient from developing permanent ketonuria.
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Affiliation(s)
- Toshiyuki Fukao
- Department of Pediatrics, Graduate School of Medicine, Gifu University, 1-1 Yanagido, Gifu, Gifu 501-1194, Japan.
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Marcus C, Alkén J, Eriksson J, Blom L, Gustafsson J. Insufficient ketone body use is the cause of ketotic hypoglycemia in one of a pair of homozygotic twins. J Clin Endocrinol Metab 2007; 92:4080-4. [PMID: 17684053 DOI: 10.1210/jc.2007-0661] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT Childhood ketotic hypoglycemia (KH) is a disease characterized by fasting hypoglycemia and increased levels of ketone bodies. The cause is unknown. OBJECTIVE The objective of the study was to study a pair of homozygotic twin boys, one of whom had severe KH from the age of 14 months, whereas the other boy was apparently healthy. DESIGN AND RESULTS At the age of 6 yr, the boys were thoroughly investigated. During a 24-h fasting tolerance test, the twin with KH showed hypoglycemia (blood glucose 2.0 mmol/liter) after 18 h. Three h before the occurrence of hypoglycemia, he had had 10 times higher beta-hydroxybutyrate levels than his brother, who showed no signs of hypoglycemia. Their glucose production rates were normal and similar (23.3 and 21.7 micromol/kg body weight per minute in the healthy and KH twin, respectively) as well as their lipolysis rates (5.8 and 6.8 micromol/kg body weight per minute, respectively). During repeated 60-min infusions of beta-hydroxybutyrate, the plasma level of beta-hydroxybutyrate increased 5-10 times more in the twin with KH (mean 1.1 mmol/liter in the healthy and 10.8 mmol/liter in the KH twin), indicating a disturbed clearance or metabolism of beta-hydroxybutyrate. No mutations were found in genes involved in ketone body metabolism or transport. CONCLUSION In the affected boy, KH seems to be the result of a reduced capacity to use ketone bodies, leading to increased peripheral metabolism of glucose that cannot be met by hepatic glucose production. Because the boys are homozygotic twins and only one of them is affected, the ketotic hypoglycemia is most likely caused by an altered imprinting of gene(s) involved in regulating metabolic pathways.
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Affiliation(s)
- Claude Marcus
- Department for Clinical Science, Intervention and Technology (Clintec), Division of Pediatrics, Karolinska University Hospital, Huddinge, SE-141 86 Stockholm, Sweden.
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11
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Kursula P, Sikkilä H, Fukao T, Kondo N, Wierenga RK. High resolution crystal structures of human cytosolic thiolase (CT): a comparison of the active sites of human CT, bacterial thiolase, and bacterial KAS I. J Mol Biol 2005; 347:189-201. [PMID: 15733928 DOI: 10.1016/j.jmb.2005.01.018] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2004] [Revised: 01/05/2005] [Accepted: 01/06/2005] [Indexed: 10/25/2022]
Abstract
Thiolases belong to a superfamily of condensing enzymes that includes also beta-ketoacyl acyl carrier protein synthases (KAS enzymes), involved in fatty acid synthesis. Here, we describe the high resolution structure of human cytosolic acetoacetyl-CoA thiolase (CT), both unliganded (at 2.3 angstroms resolution) and in complex with CoA (at 1.6 angstroms resolution). CT catalyses the condensation of two molecules of acetyl-CoA to acetoacetyl-CoA, which is the first reaction of the metabolic pathway leading to the synthesis of cholesterol. CT is a homotetramer of exact 222 symmetry. There is an excess of positively charged residues at the interdimer surface leading towards the CoA-binding pocket, possibly important for the efficient capture of substrates. The geometry of the catalytic site, including the three catalytic residues Cys92, His 353, Cys383, and the two oxyanion holes, is highly conserved between the human and bacterial Zoogloea ramigera thiolase. In human CT, the first oxyanion hole is formed by Wat38 (stabilised by Asn321) and NE2(His353), and the second by N(Cys92) and N(Gly385). The active site of this superfamily is constructed on top of four active site loops, near Cys92, Asn321, His353, and Cys383, respectively. These loops were used for the superpositioning of CT on the bacterial thiolase and on the Escherichia coli KAS I. This comparison indicates that the two thiolase oxyanion holes also exist in KAS I at topologically equivalent positions. Interestingly, the hydrogen bonding interactions at the first oxyanion hole are different in thiolase and KAS I. In KAS I, the hydrogen bonding partners are two histidine NE2 atoms, instead of a water and a NE2 side-chain atom in thiolase. The second oxyanion hole is in both structures shaped by corresponding main chain peptide NH-groups. The possible importance of bound water molecules at the catalytic site of thiolase for the reaction mechanism is discussed.
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Affiliation(s)
- Petri Kursula
- Department of Biochemistry and Biocenter Oulu, P.O. Box 3000, FIN-90014 University of Oulu, Oulu, Finland
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12
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Fukao T, Shintaku H, Kusubae R, Zhang GX, Nakamura K, Kondo M, Kondo N. Patients homozygous for the T435N mutation of succinyl-CoA:3-ketoacid CoA Transferase (SCOT) do not show permanent ketosis. Pediatr Res 2004; 56:858-63. [PMID: 15496607 DOI: 10.1203/01.pdr.0000145297.90577.67] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Succinyl-CoA:3-ketoacid CoA transferase (SCOT; locus symbol OXCT; E.C. 2.8.3.5) is the main determinant of the ketolytic capacity of tissues. Hereditary SCOT deficiency causes episodic ketoacidosis. Permanent ketosis has been regarded as a pathognomonic feature of SCOT deficiency. There are three SCOT-deficient patients from a small region in Japan and they have not manifested permanent ketosis, even though their ketoacidotic crises were as severe as those of other SCOT-deficient patients. All three were homozygous for the T435N mutation. Transient expression analysis of wild-type and mutant cDNA showed that the T435N mutant retained significant residual SCOT activities (20% for that of the wild-type at 39.5 degrees C, 25% at 37 degrees C, and 50% at 30 degrees C). The difference of residual SCOT activities at these temperatures in expression analyses was due to differences in the level of the mutant protein. SCOT activity of the T435N protein was more vulnerable than the wild-type to heat treatment at 42 degrees C and 55 degrees C. These temperature-sensitive characteristics of the mutant protein may explain, in part, why the patients developed ketoacidotic crises during febrile illness. In SCOT-deficient patients retaining some residual activity, permanent ketosis may be absent.
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Affiliation(s)
- Toshiyuki Fukao
- Department of Pediatrics, Graduate School of Medicine, Gifu University, 1-1 Yanagido, Gifu 501-1194, Japan.
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13
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Abstract
The metalloendopeptidase nardilysin contains a putative N-terminal nuclear localization signal. The functionality of this sequence was tested with nardilysin-GFP fusion constructs. Expression in NIH3T3 cells showed approximately 90-95% of nardilysin-GFP as cytoplasmic. However, 3-6% of transfected cells showed both cytosolic and nuclear staining, while 2-4% showed predominantly nuclear staining. A nuclear localization signal mutant and an N-terminally truncated nardilysin-GFP with the nuclear localization signal deleted were completely cytoplasmic. Although endogenous nardilysin was barely detectable in the nucleus, after treatment with leptomycin B, nuclear nardilysin rose to approximately 15% and to over 25% after addition of spermine. The ability of a methionine 49 to act as the sole initiator methionine, as previously proposed, was tested by inserting a c-myc epitope between leucine28 and glycine29. Expression in HEK293 cells showed the presence of the c-myc tag, demonstrating that the enzyme can be translated from the first methionine and contains the nuclear localization signal.
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Affiliation(s)
- Zhangliang Ma
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY 40536, USA
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Hiol A, Caron JM, Smith CD, Jones TLZ. Characterization and partial purification of protein fatty acyltransferase activity from rat liver. Biochim Biophys Acta Mol Cell Biol Lipids 2004; 1635:10-9. [PMID: 14642772 DOI: 10.1016/j.bbalip.2003.10.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The acylation of proteins through the addition of palmitate to cysteine residues is a common posttranslational modification for a variety of proteins, but the enzymology of this reversible modification has resisted elucidation. We developed a strategy to purify protein fatty acyltransferase (PAT) activity from rat livers that took advantage of recent knowledge on the cellular location and inhibition of PAT activity. We determined that three different thiolases have PAT activity in the presence of imidazole and therefore started the purification with a plasma membrane fraction to minimize the contamination with these enzymes. After detergent extraction of the plasma membrane fraction, the PAT activity was enriched about 90-fold by sequential chromatography including affinity chromatography to a cerulenin-based inhibitor of palmitoylation. The partially purified PAT activity (1) was lost with treatments to degrade or denature proteins, (2) could acylate tubulin, Galpha(i) and RGS16 and (3) showed a preference for palmitate and to a lesser degree other long-chain fatty acids. This purification procedure is a significant advance over previous efforts at PAT purification and a starting point for a proteomic approach for identification of mammalian PAT.
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Affiliation(s)
- Abel Hiol
- Metabolic Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
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15
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Affiliation(s)
- Werner J Kovacs
- Department of Biology, San Diego State University, San Diego, California 92182, USA
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16
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Abstract
Peroxisomes contain enzymes catalyzing a number of indispensable metabolic functions mainly related to lipid metabolism. The importance of peroxisomes in man is stressed by the existence of genetic disorders in which the biogenesis of the organelle is defective, leading to complex developmental and metabolic phenotypes. The purpose of this review is to emphasize some of the recent findings related to the localization of cholesterol biosynthetic enzymes in peroxisomes and to discuss the impairment of cholesterol biosynthesis in peroxisomal deficiency diseases.
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Affiliation(s)
- Werner J Kovacs
- Department of Biology, San Diego State University, San Diego, CA 92182, USA
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17
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Takusa Y, Fukao T, Kimura M, Uchiyama A, Abo W, Tsuboi Y, Hirose S, Fujioka H, Kondo N, Yamaguchi S. Identification and characterization of temperature-sensitive mild mutations in three Japanese patients with nonsevere forms of very-long-chain acyl-CoA dehydrogenase deficiency. Mol Genet Metab 2002; 75:227-34. [PMID: 11914034 DOI: 10.1006/mgme.2002.3297] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Very-long-chain acyl-CoA dehydrogenase (VLCAD) deficiency is clinically classified into severe, intermediate, and myopathic forms. We identified mutations in three unrelated Japanese patients with VLCAD deficiency: two with the myopathic form and one with the intermediate form, all compound heterozygotes of K264E/M437V, A416T/1798delA, and P89S/IVS16-3delAA, respectively. We characterized four missense mutations, K264E, M437V, A416T, and P89S, by transisent expression analysis, using SV40-transformed fibroblasts derived from a VLCAD-null patient, as recipient cells. In transient expression of the wild-type VLCAD cDNA, VLCAD activity at 30 degrees C was higher than at 37 degrees C. Moreover, this temperature-sensitive character is more evident in all the mutant proteins tested than in wild type. Based on characterization of the five missense mutations identified in four Japanese patients, including data on one patient with the myopathic form previously reported, patients with the nonsevere forms (intermediate or myopathic forms) have missense mutations with residual activities in at least one allele. Expression analysis at 30 degrees C may be more useful for evaluating these missense mutations, compared with that at 37 degrees C.
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Affiliation(s)
- Yuichi Takusa
- Department of Pediatrics, Shimane Medical University, Izumo, Shimane 693-8501, Japan.
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18
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Abstract
The role of alpha/beta-SNAP (Soluble NSF Attachment Protein) in vesicular trafficking is well established; however, the function of the ubiquitously expressed gamma-SNAP remains unclear. To further characterize the cellular role of this enigmatic protein, a two-hybrid screen was used to identify new, gamma-SNAP-binding proteins and to uncover potentially novel functions for gamma-SNAP. One such SNAP-binding protein, termed Gaf-1 (gamma-SNAP associate factor-1) specifically binds gamma- but not alpha-SNAP. The full-length Gaf-1 (75 kDa) is ubiquitously expressed and is found stoichiometrically associated with gamma-SNAP in cellular extracts. This binding is distinct from other SNAP interactions since no alpha-SNAP or NSF coprecipitated with Gaf-1. Subcellular fractionation and immunofluorescence analysis show that Gaf-1 is peripherally associated with the outer mitochondrial membrane. Only a fraction of gamma-SNAP was mitochondrial with the balance being either cytosolic or associated with other membrane fractions. GFP-gamma-SNAP and the C-terminal domain of Gaf-1 both show a reticular distribution in HEK-293 cells. This reticular structure colocalizes with Gaf-1 and mitochondria as well as with microtubules but not with other cytoskeletal elements. These data identify a class of gamma-SNAP interactions that is distinct from other members of the SNAP family and point to a potential role for gamma-SNAP in mitochondrial dynamics.
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Affiliation(s)
- D Chen
- Department of Biochemistry, University of Kentucky College of Medicine, Lexington, Kentucky 40536, USA
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19
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Olivier LM, Kovacs W, Masuda K, Keller G, Krisans SK. Identification of peroxisomal targeting signals in cholesterol biosynthetic enzymes: AA-CoA thiolase, HMG-CoA synthase, MPPD, and FPP synthase. J Lipid Res 2000; 41:1921-35. [DOI: 10.1016/s0022-2275(20)32353-1] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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20
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Watanabe H, Orii KE, Fukao T, Song XQ, Aoyama T, IJlst L, Ruiter J, Wanders RJ, Kondo N. Molecular basis of very long chain acyl-CoA dehydrogenase deficiency in three Israeli patients: identification of a complex mutant allele with P65L and K247Q mutations, the former being an exonic mutation causing exon 3 skipping. Hum Mutat 2000; 15:430-8. [PMID: 10790204 DOI: 10.1002/(sici)1098-1004(200005)15:5<430::aid-humu4>3.0.co;2-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Very long chain acyl-CoA dehydrogenase (VLCAD) deficiency is a life-threatening disorder of mitochondrial fatty acid beta-oxidation. We identified four novel mutations in three unrelated patients. All patients had the severe childhood form of VLCAD deficiency with early onset and high mortality. Immunoblot analysis revealed that VLCAD protein was undetectable in patients 2 and 3, whereas normal-size VLCAD protein and an aberrant form of VLCAD (4kDa smaller) were detected in patient 1. As expected, null mutations were found in patients 2 and 3: patient 2 is homozygous for a frameshift mutation, del 4 bp at 798-801, and patient 3 is homozygous for a nonsense mutation 65C>A(S22X). Patient 1 was homozygous for a complex mutant allele containing two alterations, including a 194C>T transition (P65L) and 739A>C transversion (K247Q); in the case of P65L, the amino acid change does not reduce enzyme activity. However, the nucleotide change resulted in exon 3 skipping, whereas the latter K247Q mutation had a drastic effect on enzyme activity. We verified these events by in vivo splicing experiments and transient expression analysis of mutant cDNAs. The P65L mutation locates 11 bases upstream of a splice donor site of intron 3. This is an example of an exonic mutation which affects exon-splicing.
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Affiliation(s)
- H Watanabe
- Department of Pediatrics, Gifu University School of Medicine, Gifu, Japan
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21
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Antonenkov VD, Croes K, Waelkens E, Van Veldhoven PP, Mannaerts GP. Identification, purification and characterization of an acetoacetyl-CoA thiolase from rat liver peroxisomes. Eur J Biochem 2000; 267:2981-90. [PMID: 10806397 DOI: 10.1046/j.1432-1033.2000.01314.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Acetoacetyl-CoA specific thiolases catalyse the cleavage of acetoacetyl-CoA into two molecules of acetyl-CoA and the synthesis (reverse reaction) of acetoacetyl-CoA. The formation of acetoacetyl-CoA is the first step in cholesterol and ketone body synthesis. In this report we describe the identification of a novel acetoacetyl-CoA thiolase and its purification from isolated rat liver peroxisomes by column chromatography. The enzyme, which is a homotetramer with a subunit molecular mass of 42 kDa, could be distinguished from the cytosolic and mitochondrial acetoacetyl-CoA thiolases by its chromatographic behaviour, kinetic characteristics and partial internal amino-acid sequences. The enzyme did not catalyse the cleavage of medium or long chain 3-oxoacyl-CoAs. The enzyme cross-reacted with polyclonal antibodies raised against cytosolic acetoacetyl-CoA thiolase. The latter property was exploited to confirm the peroxisomal localization of the novel thiolase in subcellular fractionation experiments. The peroxisomal acetoacetyl-CoA thiolase most probably catalyses the first reaction in peroxisomal cholesterol and dolichol synthesis. In addition, its presence in peroxisomes along with the other enzymes of the ketogenic pathway indicates that the ketogenic potential of peroxisomes needs to be re-evaluated.
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Affiliation(s)
- V D Antonenkov
- Departement Moleculaire Celbiologie Afdeling Farmacologie en Biochemie, Katholieke Universiteit Leuven, Campus Gasthuisberg, Belgium
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Abstract
The human acetyl-CoA acetyltransferase 2 gene, ACAT2, codes for a thiolase, an enzyme involved in lipid metabolism. The human T-complex protein 1 gene, TCP1, encodes a molecular chaperone of the chaperonin family. The two genes overlap by their 3'-untranslated regions, their coding sequences being located on opposite DNA strands in a tail-to-tail orientation. To find out how the overlap might have arisen in evolution, the homologous genes of the zebrafish, the African toad, caiman, platypus, opossum, and wallaby were identified. In each species, standard or long polymerase chain reactions were used to determine whether the ACAT2 and TCP1 homologs are closely linked and, if so, whether they overlap. The results reveal that the overlap apparently arose during the transition from therapsid reptiles to mammals and has been retained for >200 million years. Part of the overlapping untranslated region shows remarkable sequence conservation. The overlap presumably arose during the chromosomal rearrangement that brought the two unrelated and previously separated genes together. One or both of the transposed genes found by chance signals that are necessary for the processing of their transcripts to be present on the noncoding strand of the partner gene.
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Affiliation(s)
- S Shintani
- Max-Planck-Institut für Biologie, D-72076 Tübingen, Germany
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Abstract
The enzymes involved in beta-oxidation spiral are schematically classified into two groups. The first group consists of palmitoyl-CoA oxidase, the L-bifunctional protein, which has been called as the bifunctional protein, and 3-ketoacyl-CoA thiolase. The second group consists of the newly confirmed enzymes, branched chain oxidase, the D-bifunctional protein, and sterol carrier protein x. The enzymes of the first group are inducible and act on the straight chain acyl-CoA substrates. But the enzymes of the second group are non-inducible and act on branched chain acyl-CoAs. Accordingly, bile acid formation and oxidation of pristanic acid derived from phytol are catalyzed by the enzymes of the second group but not by those of the first group. The functions of the peroxisomal system and methods of analysis of the enzymes are briefly summarized.
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Affiliation(s)
- T Hashimoto
- Department of Biochemistry, Shinshu University School of Medicine, Matsumoto, Nagano, Japan
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Watanabe H, Yamaguchi S, Kimura M, Wakazono A, Song XQ, Fukao T, Orii T, Hashimoto T. Practical assay method of cytosolic acetoacetyl-CoA thiolase by rapid release of cytosolic enzymes from cultured lymphocytes using digitonin. TOHOKU J EXP MED 1998; 184:29-38. [PMID: 9607396 DOI: 10.1620/tjem.184.29] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
We designed a simple approach to determine cytosolic acetoacetyl-CoA thiolase (CT) activity for differential diagnosis of ketone body catabolic defects, using rapid cell-subfractionation of cultured lymphocytes with digitonin. Efficiency of cell subfractionation was determined by measurement of lactate dehydrogenase and citrate synthetase as marker enzymes for cytosol and organelle fractions, respectively, and confirmed by immunotitration and immunoblotting using antibodies against cytosolic and mitochondrial thiolases, respectively. In the condition of best separation taken in the presence of 1 mg/ml digitonin, acetoacetyl-CoA thiolase activities in the presence of K+ ion in the cytosol and organelle fractions were 138.3+/-39.2 and 84.0+/-16.2 nmol/min/ml, respectively. The thiolase activity in the organelle fraction was doubled by the presence of K+ ion, whereas that in the cytosol fraction was not affected. The thiolase activity in the organelle fraction was reduced by the treatment of anti-mitochondrial acetoacetyl-CoA thiolase (T2) antibody but not by anti-CT antibody. On the other hand, that in the cytosol fraction was significantly decreased by anti-CT antibody but not by anti-T2 antibody. These data suggested that T2 was collected in the organelle fraction, and that CT activity could be assessed by measurement of the thiolase activity in the cytosolic fraction. Succinyl-CoA: 3-ketoacid CoA transferase (SCOT), whose defect is the third inherited disorder of ketone body catabolism, was collected in the organelle fraction. Hence, this method will prove to be useful for accurate assessment of defects of CT as well as T2 or SCOT, all involved in ketone body catabolism.
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Affiliation(s)
- H Watanabe
- Department of Pediatrics, Shimane Medical University, Izumo, Japan
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25
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Affiliation(s)
- T Hashimoto
- Department of Biochemistry, Shinshu University School of Medicine, Nagano, Japan
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