Title: <scp>SIRT</scp> 5 inhibits peroxisomal <scp>ACOX</scp> 1 to prevent oxidative damage and is downregulated in liver cancer
Abstract: Article28 February 2018free access Source DataTransparent process SIRT5 inhibits peroxisomal ACOX1 to prevent oxidative damage and is downregulated in liver cancer Xiu-Fei Chen Molecular and Cell Biology Lab, Institute of Biomedical Sciences, Shanghai Medical College, Shanghai, China Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai, China State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China Search for more papers by this author Meng-Xin Tian orcid.org/0000-0002-5315-1780 Department of Liver Surgery, Liver Cancer Institute, Zhongshan Hospital, Fudan University, Shanghai, China Key Laboratory of Carcinogenesis and Cancer Invasion of Ministry of Education, Shanghai, China Search for more papers by this author Ren-Qiang Sun Molecular and Cell Biology Lab, Institute of Biomedical Sciences, Shanghai Medical College, Shanghai, China Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai, China State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China Search for more papers by this author Meng-Li Zhang Molecular and Cell Biology Lab, Institute of Biomedical Sciences, Shanghai Medical College, Shanghai, China Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai, China State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China Search for more papers by this author Li-Sha Zhou Molecular and Cell Biology Lab, Institute of Biomedical Sciences, Shanghai Medical College, Shanghai, China Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai, China State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China Search for more papers by this author Lei Jin Department of Liver Surgery, Liver Cancer Institute, Zhongshan Hospital, Fudan University, Shanghai, China Key Laboratory of Carcinogenesis and Cancer Invasion of Ministry of Education, Shanghai, China Search for more papers by this author Lei-Lei Chen Molecular and Cell Biology Lab, Institute of Biomedical Sciences, Shanghai Medical College, Shanghai, China Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai, China State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China Search for more papers by this author Wen-Jie Zhou Molecular and Cell Biology Lab, Institute of Biomedical Sciences, Shanghai Medical College, Shanghai, China Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai, China State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China Search for more papers by this author Kun-Long Duan Molecular and Cell Biology Lab, Institute of Biomedical Sciences, Shanghai Medical College, Shanghai, China Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai, China State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China Search for more papers by this author Yu-Jia Chen Molecular and Cell Biology Lab, Institute of Biomedical Sciences, Shanghai Medical College, Shanghai, China Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai, China State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China Search for more papers by this author Chao Gao Molecular and Cell Biology Lab, Institute of Biomedical Sciences, Shanghai Medical College, Shanghai, China Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai, China State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China Search for more papers by this author Zhou-Li Cheng Molecular and Cell Biology Lab, Institute of Biomedical Sciences, Shanghai Medical College, Shanghai, China Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai, China State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China Search for more papers by this author Fang Wang Molecular and Cell Biology Lab, Institute of Biomedical Sciences, Shanghai Medical College, Shanghai, China Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai, China State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China Search for more papers by this author Jin-Ye Zhang Molecular and Cell Biology Lab, Institute of Biomedical Sciences, Shanghai Medical College, Shanghai, China Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai, China State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China Search for more papers by this author Yi-Ping Sun Molecular and Cell Biology Lab, Institute of Biomedical Sciences, Shanghai Medical College, Shanghai, China Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai, China State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China Search for more papers by this author Hong-Xiu Yu Molecular and Cell Biology Lab, Institute of Biomedical Sciences, Shanghai Medical College, Shanghai, China Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai, China State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China Search for more papers by this author Yu-Zheng Zhao School of Pharmacy, East China University of Science and Technology, Shanghai, China Search for more papers by this author Yi Yang School of Pharmacy, East China University of Science and Technology, Shanghai, China Search for more papers by this author Wei-Ren Liu Department of Liver Surgery, Liver Cancer Institute, Zhongshan Hospital, Fudan University, Shanghai, China Key Laboratory of Carcinogenesis and Cancer Invasion of Ministry of Education, Shanghai, China Search for more papers by this author Ying-Hong Shi Department of Liver Surgery, Liver Cancer Institute, Zhongshan Hospital, Fudan University, Shanghai, China Key Laboratory of Carcinogenesis and Cancer Invasion of Ministry of Education, Shanghai, China Search for more papers by this author Yue Xiong orcid.org/0000-0003-2744-6566 Molecular and Cell Biology Lab, Institute of Biomedical Sciences, Shanghai Medical College, Shanghai, China Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai, China State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China Lineberger Comprehensive Cancer Center, Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA Search for more papers by this author Kun-Liang Guan orcid.org/0000-0003-1892-0174 Molecular and Cell Biology Lab, Institute of Biomedical Sciences, Shanghai Medical College, Shanghai, China Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai, China State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China Department of Pharmacology and Moores Cancer Center, University of California San Diego, La Jolla, CA, USA Search for more papers by this author Dan Ye Corresponding Author [email protected] orcid.org/0000-0003-4848-0501 Molecular and Cell Biology Lab, Institute of Biomedical Sciences, Shanghai Medical College, Shanghai, China Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai, China State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China Department of General Surgery, Huashan Hospital, Fudan University, Shanghai, China Search for more papers by this author Xiu-Fei Chen Molecular and Cell Biology Lab, Institute of Biomedical Sciences, Shanghai Medical College, Shanghai, China Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai, China State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China Search for more papers by this author Meng-Xin Tian orcid.org/0000-0002-5315-1780 Department of Liver Surgery, Liver Cancer Institute, Zhongshan Hospital, Fudan University, Shanghai, China Key Laboratory of Carcinogenesis and Cancer Invasion of Ministry of Education, Shanghai, China Search for more papers by this author Ren-Qiang Sun Molecular and Cell Biology Lab, Institute of Biomedical Sciences, Shanghai Medical College, Shanghai, China Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai, China State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China Search for more papers by this author Meng-Li Zhang Molecular and Cell Biology Lab, Institute of Biomedical Sciences, Shanghai Medical College, Shanghai, China Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai, China State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China Search for more papers by this author Li-Sha Zhou Molecular and Cell Biology Lab, Institute of Biomedical Sciences, Shanghai Medical College, Shanghai, China Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai, China State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China Search for more papers by this author Lei Jin Department of Liver Surgery, Liver Cancer Institute, Zhongshan Hospital, Fudan University, Shanghai, China Key Laboratory of Carcinogenesis and Cancer Invasion of Ministry of Education, Shanghai, China Search for more papers by this author Lei-Lei Chen Molecular and Cell Biology Lab, Institute of Biomedical Sciences, Shanghai Medical College, Shanghai, China Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai, China State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China Search for more papers by this author Wen-Jie Zhou Molecular and Cell Biology Lab, Institute of Biomedical Sciences, Shanghai Medical College, Shanghai, China Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai, China State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China Search for more papers by this author Kun-Long Duan Molecular and Cell Biology Lab, Institute of Biomedical Sciences, Shanghai Medical College, Shanghai, China Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai, China State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China Search for more papers by this author Yu-Jia Chen Molecular and Cell Biology Lab, Institute of Biomedical Sciences, Shanghai Medical College, Shanghai, China Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai, China State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China Search for more papers by this author Chao Gao Molecular and Cell Biology Lab, Institute of Biomedical Sciences, Shanghai Medical College, Shanghai, China Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai, China State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China Search for more papers by this author Zhou-Li Cheng Molecular and Cell Biology Lab, Institute of Biomedical Sciences, Shanghai Medical College, Shanghai, China Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai, China State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China Search for more papers by this author Fang Wang Molecular and Cell Biology Lab, Institute of Biomedical Sciences, Shanghai Medical College, Shanghai, China Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai, China State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China Search for more papers by this author Jin-Ye Zhang Molecular and Cell Biology Lab, Institute of Biomedical Sciences, Shanghai Medical College, Shanghai, China Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai, China State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China Search for more papers by this author Yi-Ping Sun Molecular and Cell Biology Lab, Institute of Biomedical Sciences, Shanghai Medical College, Shanghai, China Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai, China State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China Search for more papers by this author Hong-Xiu Yu Molecular and Cell Biology Lab, Institute of Biomedical Sciences, Shanghai Medical College, Shanghai, China Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai, China State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China Search for more papers by this author Yu-Zheng Zhao School of Pharmacy, East China University of Science and Technology, Shanghai, China Search for more papers by this author Yi Yang School of Pharmacy, East China University of Science and Technology, Shanghai, China Search for more papers by this author Wei-Ren Liu Department of Liver Surgery, Liver Cancer Institute, Zhongshan Hospital, Fudan University, Shanghai, China Key Laboratory of Carcinogenesis and Cancer Invasion of Ministry of Education, Shanghai, China Search for more papers by this author Ying-Hong Shi Department of Liver Surgery, Liver Cancer Institute, Zhongshan Hospital, Fudan University, Shanghai, China Key Laboratory of Carcinogenesis and Cancer Invasion of Ministry of Education, Shanghai, China Search for more papers by this author Yue Xiong orcid.org/0000-0003-2744-6566 Molecular and Cell Biology Lab, Institute of Biomedical Sciences, Shanghai Medical College, Shanghai, China Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai, China State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China Lineberger Comprehensive Cancer Center, Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA Search for more papers by this author Kun-Liang Guan orcid.org/0000-0003-1892-0174 Molecular and Cell Biology Lab, Institute of Biomedical Sciences, Shanghai Medical College, Shanghai, China Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai, China State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China Department of Pharmacology and Moores Cancer Center, University of California San Diego, La Jolla, CA, USA Search for more papers by this author Dan Ye Corresponding Author [email protected] orcid.org/0000-0003-4848-0501 Molecular and Cell Biology Lab, Institute of Biomedical Sciences, Shanghai Medical College, Shanghai, China Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai, China State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China Department of General Surgery, Huashan Hospital, Fudan University, Shanghai, China Search for more papers by this author Author Information Xiu-Fei Chen1,2,3, Meng-Xin Tian4,5, Ren-Qiang Sun1,2,3, Meng-Li Zhang1,2,3, Li-Sha Zhou1,2,3, Lei Jin4,5, Lei-Lei Chen1,2,3, Wen-Jie Zhou1,2,3, Kun-Long Duan1,2,3, Yu-Jia Chen1,2,3, Chao Gao1,2,3, Zhou-Li Cheng1,2,3, Fang Wang1,2,3, Jin-Ye Zhang1,2,3, Yi-Ping Sun1,2,3, Hong-Xiu Yu1,2,3, Yu-Zheng Zhao6, Yi Yang6, Wei-Ren Liu4,5, Ying-Hong Shi4,5, Yue Xiong1,2,3,7, Kun-Liang Guan1,2,3,8 and Dan Ye *,1,2,3,9 1Molecular and Cell Biology Lab, Institute of Biomedical Sciences, Shanghai Medical College, Shanghai, China 2Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai, China 3State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China 4Department of Liver Surgery, Liver Cancer Institute, Zhongshan Hospital, Fudan University, Shanghai, China 5Key Laboratory of Carcinogenesis and Cancer Invasion of Ministry of Education, Shanghai, China 6School of Pharmacy, East China University of Science and Technology, Shanghai, China 7Lineberger Comprehensive Cancer Center, Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA 8Department of Pharmacology and Moores Cancer Center, University of California San Diego, La Jolla, CA, USA 9Department of General Surgery, Huashan Hospital, Fudan University, Shanghai, China *Corresponding author. Tel: +86 21 54237834; E-mail: [email protected] EMBO Rep (2018)19:e45124https://doi.org/10.15252/embr.201745124 PDFDownload PDF of article text and main figures. Peer ReviewDownload a summary of the editorial decision process including editorial decision letters, reviewer comments and author responses to feedback. ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareFacebookTwitterLinked InMendeleyWechatReddit Figures & Info Abstract Peroxisomes account for ~35% of total H2O2 generation in mammalian tissues. Peroxisomal ACOX1 (acyl-CoA oxidase 1) is the first and rate-limiting enzyme in fatty acid β-oxidation and a major producer of H2O2. ACOX1 dysfunction is linked to peroxisomal disorders and hepatocarcinogenesis. Here, we show that the deacetylase sirtuin 5 (SIRT5) is present in peroxisomes and that ACOX1 is a physiological substrate of SIRT5. Mechanistically, SIRT5-mediated desuccinylation inhibits ACOX1 activity by suppressing its active dimer formation in both cultured cells and mouse livers. Deletion of SIRT5 increases H2O2 production and oxidative DNA damage, which can be alleviated by ACOX1 knockdown. We show that SIRT5 downregulation is associated with increased succinylation and activity of ACOX1 and oxidative DNA damage response in hepatocellular carcinoma (HCC). Our study reveals a novel role of SIRT5 in inhibiting peroxisome-induced oxidative stress, in liver protection, and in suppressing HCC development. Synopsis This study reveals a role for SIRT5 in regulating peroxisomal H2O2 and ROS homeostasis and indicates its potential function in liver protection and hepatocellular carcinoma suppression. SIRT5 is localized in peroxisomes where it controls H2O2 metabolism. SIRT5-mediated desuccinylation inhibits ACOX1 activity by suppressing its active dimer formation. SIRT5 downregulation increases ACOX1 activity and oxidative DNA damage response in HCC. Introduction Peroxisomes are ubiquitous and highly dynamic organelles, which are involved in the catabolism of very-long-chain fatty acids (VLCFAs), branched-chain fatty acids, D-amino acids, polyamines, and the biosynthesis of ether lipids and bile acids 1, 2. Dysfunctions in peroxisomal metabolism are linked to inherited peroxisomal disorders, age-related diseases, and human cancers 3, 4. Clinically, peroxisomal disorders refer to either peroxisome biogenesis disorders or single peroxisomal enzyme deficiencies 5. The former group is mainly associated with mutations in the genes encoding for peroxisomal biogenesis factors (also known as peroxins or PEX), which are involved in the import of peroxisomal proteins from the cytoplasm 6. The latter group is caused by defects in peroxisomal matrix enzymes or membrane proteins which can affect specific peroxisome-dependent metabolic pathways 7, 8. In peroxisomes, ACOX1 (acyl-CoA oxidase 1, EC 1.3.3.6) is the first and a rate-limiting enzyme which catalyzes the desaturation of very-long-chain acyl-CoAs to 2-trans-enoyl-CoAs, and transfers electrons in the form of H− from their prosthetic group FADH2 to molecular oxygen to generate hydrogen peroxide (H2O2) 9. This step is distinguished from the desaturation of long-, middle- and short-chain acyl-CoAs to trans 2,3-dehydroacyl-CoA catalyzed by acyl-CoA dehydrogenases (ACADs) in mitochondria, which transfers electrons to flavin adenine dinucleotide (FAD) and generates FADH2 used for ATP production in the respiratory chain 10. H2O2 is relatively stable and less reactive as compared to other reactive oxygen species (ROS), such as superoxide anion (), hydroxyl radicals (OH·), and peroxyradicals (ROO·). Lack of electric charge enables H2O2 to cross membranes. Several previous studies have reported that H2O2 generated by peroxisomes can rapidly (within seconds) diffuse across lipid bilayer membranes and enter into nuclei 11-13. H2O2 is known to be implicated in redox regulation of multiple signal transduction pathways when produced at low levels 14-16. Once entering into nuclei, H2O2 can induce stalled replication forks and DNA double-strand breaks and cause oxidative DNA damage, and is thus involved in the processes of mutagenesis, aging, and carcinogenesis 17-20. Previous studies have shown that the ACOX1 gene is under the control of peroxisome proliferator-activated receptor alpha (PPARα) 21. Abnormal upregulation of ACOX1 by PPAR activation was reported to stimulate hepatic fatty acid oxidation, accompanied by H2O2 accumulation, resulting in excess energy burning in the liver and contributing to the development of liver cancer in rodents 22, 23. Acox1-null mice exhibit growth retardation, infertility, excess VLCFAs in the blood, and develop progressive liver diseases with increased intrahepatic H2O2 levels derived from mitochondrial and microsomal fatty acid oxidation and other sources 22, 24-26. Together, these findings suggest that peroxisomal ACOX1 is crucial for fatty acid oxidation and H2O2 homeostasis in liver tissue and that ACOX1 dysfunction contributes to the development of chronic liver disease and hepatocarcinogenesis. Thus far, how ACOX1 is regulated to meet the need for VLCFA catabolism and to control cellular H2O2 levels and redox homeostasis is poorly understood. Much of efforts on understanding the regulation of ACOX1 have been focused at its transcriptional control, while the post-translational modifications of ACOX1 are greatly unknown. Large-scale proteomic studies of cellular proteins have revealed that acetylation, succinylation, malonylation, and glutarylation can regulate multiple metabolic processes 27. Among these acylations, lysine succinylation, malonylation, and glutarylation are commonly regulated by the deacylase sirtuin 5 (SIRT5) 28-30. All these post-translational modifications occur on the ε group of a Lys residue, suggesting the possibility that different modification may compete or block each other, allowing signals from different physiological conditions or pathways to be integrated on or sensed by a common protein. Notably, multiple succinylation sites in ACOX1 have been identified in SIRT5 knockout (KO) versus wild-type HeLa cells and mouse livers 30, 31, implying that ACOX1 may be a potential substrate of SIRT5. In this study, we discover that ACOX1 is a physiological substrate of SIRT5 as SIRT5-dependent desuccinylation inhibits ACOX1 activity by suppressing its active dimer formation. We show that SIRT5 loss is associated with increased succinylation and activity of ACOX1 in cultured cells, mouse liver tissues, and human HCC cancer samples. Results SIRT5 can localize in peroxisomes where it regulates H2O2 metabolism and cellular redox status As mentioned above, significant amount of H2O2 is produced during the ACOX1-catalyzed reaction, raising the question how cells balance the need for VLCFA catabolism and control of cellular H2O2 levels and redox homeostasis. Several recent proteomic studies in mouse liver and skeletal muscle have identified a large number of succinylated proteins as potential substrates