1
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Zheng Y, Chen J, Macwan V, Dixon CL, Li X, Liu S, Yu Y, Xu P, Sun Q, Hu Q, Liu W, Raught B, Fairn GD, Neculai D. S-acylation of ATGL is required for lipid droplet homoeostasis in hepatocytes. Nat Metab 2024:10.1038/s42255-024-01085-w. [PMID: 39143266 DOI: 10.1038/s42255-024-01085-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Accepted: 06/21/2024] [Indexed: 08/16/2024]
Abstract
Lipid droplets (LDs) are organelles specialized in the storage of neutral lipids, cholesterol esters and triglycerides, thereby protecting cells from the toxicity of excess lipids while allowing for the mobilization of lipids in times of nutrient deprivation. Defects in LD function are associated with many diseases. S-acylation mediated by zDHHC acyltransferases modifies thousands of proteins, yet the physiological impact of this post-translational modification on individual proteins is poorly understood. Here, we show that zDHHC11 regulates LD catabolism by modifying adipose triacylglyceride lipase (ATGL), the rate-limiting enzyme of lipolysis, both in hepatocyte cultures and in mice. zDHHC11 S-acylates ATGL at cysteine 15. Preventing the S-acylation of ATGL renders it catalytically inactive despite proper localization. Overexpression of zDHHC11 reduces LD size, whereas its elimination enlarges LDs. Mutating ATGL cysteine 15 phenocopies zDHHC11 loss, causing LD accumulation, defective lipolysis and lipophagy. Our results reveal S-acylation as a mode of regulation of ATGL function and LD homoeostasis. Modulating this pathway may offer therapeutic potential for treating diseases linked to defective lipolysis, such as fatty liver disease.
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Affiliation(s)
- Yuping Zheng
- Center for Metabolism Research, The Fourth Affiliated Hospital of School of Medicine and International School of Medicine, International Institutes of Medicine, Zhejiang University, Yiwu, China
| | - Jishun Chen
- Department of Cell Biology, Zhejiang University School of Medicine, Hangzhou, China
| | - Vinitha Macwan
- Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, Canada
| | - Charneal L Dixon
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital, University Health Network, Toronto, Ontario, Canada
- Department of Pathology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Xinran Li
- ZJU-Hangzhou Global Scientific and Technological Innovation Center, Hangzhou, China
| | - Shengjie Liu
- Westlake AI Therapeutics Lab, Westlake Laboratory of Life Sciences and Biomedicine, School of Life Sciences, Westlake University, Hangzhou, China
| | - Yuyun Yu
- Center for Metabolism Research, The Fourth Affiliated Hospital of School of Medicine and International School of Medicine, International Institutes of Medicine, Zhejiang University, Yiwu, China
| | - Pinglong Xu
- Life Science Institute, Zhejiang University, Hangzhou, China
| | - Qiming Sun
- Center for Metabolism Research, The Fourth Affiliated Hospital of School of Medicine and International School of Medicine, International Institutes of Medicine, Zhejiang University, Yiwu, China
| | - Qi Hu
- Westlake AI Therapeutics Lab, Westlake Laboratory of Life Sciences and Biomedicine, School of Life Sciences, Westlake University, Hangzhou, China
| | - Wei Liu
- Center for Metabolism Research, The Fourth Affiliated Hospital of School of Medicine and International School of Medicine, International Institutes of Medicine, Zhejiang University, Yiwu, China.
| | - Brian Raught
- Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, Canada.
| | - Gregory D Fairn
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital, University Health Network, Toronto, Ontario, Canada.
- Department of Pathology, Dalhousie University, Halifax, Nova Scotia, Canada.
| | - Dante Neculai
- Center for Metabolism Research, The Fourth Affiliated Hospital of School of Medicine and International School of Medicine, International Institutes of Medicine, Zhejiang University, Yiwu, China.
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2
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Dennis KMJH, Heather LC. Post-translational palmitoylation of metabolic proteins. Front Physiol 2023; 14:1122895. [PMID: 36909239 PMCID: PMC9998952 DOI: 10.3389/fphys.2023.1122895] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Accepted: 02/03/2023] [Indexed: 03/14/2023] Open
Abstract
Numerous cellular proteins are post-translationally modified by addition of a lipid group to their structure, which dynamically influences the proteome by increasing hydrophobicity of proteins often impacting protein conformation, localization, stability, and binding affinity. These lipid modifications include myristoylation and palmitoylation. Palmitoylation involves a 16-carbon saturated fatty acyl chain being covalently linked to a cysteine thiol through a thioester bond. Palmitoylation is unique within this group of modifications, as the addition of the palmitoyl group is reversible and enzyme driven, rapidly affecting protein targeting, stability and subcellular trafficking. The palmitoylation reaction is catalyzed by a large family of Asp-His-His-Cys (DHHCs) motif-containing palmitoyl acyltransferases, while the reverse reaction is catalyzed by acyl-protein thioesterases (APTs), that remove the acyl chain. Palmitoyl-CoA serves an important dual purpose as it is not only a key metabolite fueling energy metabolism, but is also a substrate for this PTM. In this review, we discuss protein palmitoylation in regulating substrate metabolism, focusing on membrane transport proteins and kinases that participate in substrate uptake into the cell. We then explore the palmitoylation of mitochondrial proteins and the palmitoylation regulatory enzymes, a less explored field for potential lipid metabolic regulation.
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Affiliation(s)
- Kaitlyn M J H Dennis
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Lisa C Heather
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
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3
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Pei X, Li KY, Shen Y, Li JT, Lei MZ, Fang CY, Lu HJ, Yang HJ, Wen W, Yin M, Qu J, Lei QY. Palmitoylation of MDH2 by ZDHHC18 activates mitochondrial respiration and accelerates ovarian cancer growth. SCIENCE CHINA. LIFE SCIENCES 2022; 65:2017-2030. [PMID: 35366151 DOI: 10.1007/s11427-021-2048-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Accepted: 12/16/2021] [Indexed: 12/22/2022]
Abstract
Epithelial ovarian cancer (EOC) exhibits strong dependency on the tricarboxylic acid (TCA) cycle and oxidative phosphorylation to fuel anabolic process. Here, we show that malate dehydrogenase 2 (MDH2), a key enzyme of the TCA cycle, is palmitoylated at cysteine 138 (C138) residue, resulting in increased activity of MDH2. We next identify that ZDHHC18 acts as a palmitoyltransferase of MDH2. Glutamine deprivation enhances MDH2 palmitoylation by increasing the binding between ZDHHC18 and MDH2. MDH2 silencing represses mitochondrial respiration as well as ovarian cancer cell proliferation both in vitro and in vivo. Intriguingly, re-expression of wild-type MDH2, but not its palmitoylation-deficient C138S mutant, sustains mitochondrial respiration and restores the growth as well as clonogenic capability of ovarian cancer cells. Notably, MDH2 palmitoylation level is elevated in clinical cancer samples from patients with high-grade serous ovarian cancer. These observations suggest that MDH2 palmitoylation catalyzed by ZDHHC18 sustains mitochondrial respiration and promotes the malignancy of ovarian cancer, yielding possibilities of targeting ZDHHC18-mediated MDH2 palmitoylation in the treatment of EOC.
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Affiliation(s)
- Xuan Pei
- Fudan University Shanghai Cancer Center & Institutes of Biomedical Sciences; Cancer Institutes; Key Laboratory of Breast Cancer in Shanghai; Shanghai Key Laboratory of Radiation Oncology; The Shanghai Key Laboratory of Medical Epigenetics, Shanghai Medical College, Fudan University, Shanghai, 200032, China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, 200032, China.,Department of Gynecological Oncology, Fudan University Shanghai Cancer Center, Shanghai, 200032, China
| | - Kai-Yue Li
- Fudan University Shanghai Cancer Center & Institutes of Biomedical Sciences; Cancer Institutes; Key Laboratory of Breast Cancer in Shanghai; Shanghai Key Laboratory of Radiation Oncology; The Shanghai Key Laboratory of Medical Epigenetics, Shanghai Medical College, Fudan University, Shanghai, 200032, China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, 200032, China
| | - Yuan Shen
- Fudan University Shanghai Cancer Center & Institutes of Biomedical Sciences; Cancer Institutes; Key Laboratory of Breast Cancer in Shanghai; Shanghai Key Laboratory of Radiation Oncology; The Shanghai Key Laboratory of Medical Epigenetics, Shanghai Medical College, Fudan University, Shanghai, 200032, China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, 200032, China
| | - Jin-Tao Li
- Fudan University Shanghai Cancer Center & Institutes of Biomedical Sciences; Cancer Institutes; Key Laboratory of Breast Cancer in Shanghai; Shanghai Key Laboratory of Radiation Oncology; The Shanghai Key Laboratory of Medical Epigenetics, Shanghai Medical College, Fudan University, Shanghai, 200032, China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, 200032, China
| | - Ming-Zhu Lei
- Fudan University Shanghai Cancer Center & Institutes of Biomedical Sciences; Cancer Institutes; Key Laboratory of Breast Cancer in Shanghai; Shanghai Key Laboratory of Radiation Oncology; The Shanghai Key Laboratory of Medical Epigenetics, Shanghai Medical College, Fudan University, Shanghai, 200032, China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, 200032, China
| | - Cai-Yun Fang
- Fudan University Shanghai Cancer Center & Institutes of Biomedical Sciences; Cancer Institutes; Key Laboratory of Breast Cancer in Shanghai; Shanghai Key Laboratory of Radiation Oncology; The Shanghai Key Laboratory of Medical Epigenetics, Shanghai Medical College, Fudan University, Shanghai, 200032, China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, 200032, China
| | - Hao-Jie Lu
- Fudan University Shanghai Cancer Center & Institutes of Biomedical Sciences; Cancer Institutes; Key Laboratory of Breast Cancer in Shanghai; Shanghai Key Laboratory of Radiation Oncology; The Shanghai Key Laboratory of Medical Epigenetics, Shanghai Medical College, Fudan University, Shanghai, 200032, China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, 200032, China
| | - Hui-Juan Yang
- Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, 200032, China.,Department of Gynecological Oncology, Fudan University Shanghai Cancer Center, Shanghai, 200032, China
| | - Wenyu Wen
- Fudan University Shanghai Cancer Center & Institutes of Biomedical Sciences; Cancer Institutes; Key Laboratory of Breast Cancer in Shanghai; Shanghai Key Laboratory of Radiation Oncology; The Shanghai Key Laboratory of Medical Epigenetics, Shanghai Medical College, Fudan University, Shanghai, 200032, China.,State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, 200032, China
| | - Miao Yin
- Fudan University Shanghai Cancer Center & Institutes of Biomedical Sciences; Cancer Institutes; Key Laboratory of Breast Cancer in Shanghai; Shanghai Key Laboratory of Radiation Oncology; The Shanghai Key Laboratory of Medical Epigenetics, Shanghai Medical College, Fudan University, Shanghai, 200032, China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, 200032, China
| | - Jia Qu
- Fudan University Shanghai Cancer Center & Institutes of Biomedical Sciences; Cancer Institutes; Key Laboratory of Breast Cancer in Shanghai; Shanghai Key Laboratory of Radiation Oncology; The Shanghai Key Laboratory of Medical Epigenetics, Shanghai Medical College, Fudan University, Shanghai, 200032, China. .,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, 200032, China.
| | - Qun-Ying Lei
- Fudan University Shanghai Cancer Center & Institutes of Biomedical Sciences; Cancer Institutes; Key Laboratory of Breast Cancer in Shanghai; Shanghai Key Laboratory of Radiation Oncology; The Shanghai Key Laboratory of Medical Epigenetics, Shanghai Medical College, Fudan University, Shanghai, 200032, China. .,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, 200032, China. .,State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, 200032, China.
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4
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Soria LR, Makris G, D'Alessio AM, De Angelis A, Boffa I, Pravata VM, Rüfenacht V, Attanasio S, Nusco E, Arena P, Ferenbach AT, Paris D, Cuomo P, Motta A, Nitzahn M, Lipshutz GS, Martínez-Pizarro A, Richard E, Desviat LR, Häberle J, van Aalten DMF, Brunetti-Pierri N. O-GlcNAcylation enhances CPS1 catalytic efficiency for ammonia and promotes ureagenesis. Nat Commun 2022; 13:5212. [PMID: 36064721 PMCID: PMC9445089 DOI: 10.1038/s41467-022-32904-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Accepted: 08/24/2022] [Indexed: 11/09/2022] Open
Abstract
Life-threatening hyperammonemia occurs in both inherited and acquired liver diseases affecting ureagenesis, the main pathway for detoxification of neurotoxic ammonia in mammals. Protein O-GlcNAcylation is a reversible and nutrient-sensitive post-translational modification using as substrate UDP-GlcNAc, the end-product of hexosamine biosynthesis pathway. Here we show that increased liver UDP-GlcNAc during hyperammonemia increases protein O-GlcNAcylation and enhances ureagenesis. Mechanistically, O-GlcNAcylation on specific threonine residues increased the catalytic efficiency for ammonia of carbamoyl phosphate synthetase 1 (CPS1), the rate-limiting enzyme in ureagenesis. Pharmacological inhibition of O-GlcNAcase, the enzyme removing O-GlcNAc from proteins, resulted in clinically relevant reductions of systemic ammonia in both genetic (hypomorphic mouse model of propionic acidemia) and acquired (thioacetamide-induced acute liver failure) mouse models of liver diseases. In conclusion, by fine-tuned control of ammonia entry into ureagenesis, hepatic O-GlcNAcylation of CPS1 increases ammonia detoxification and is a novel target for therapy of hyperammonemia in both genetic and acquired diseases.
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Affiliation(s)
- Leandro R Soria
- Telethon Institute of Genetics and Medicine, Pozzuoli, Italy.
| | - Georgios Makris
- Division of Metabolism and Children's Research Center, University Children's Hospital, Zurich, Switzerland
| | | | | | - Iolanda Boffa
- Telethon Institute of Genetics and Medicine, Pozzuoli, Italy
| | | | - Véronique Rüfenacht
- Division of Metabolism and Children's Research Center, University Children's Hospital, Zurich, Switzerland
| | | | - Edoardo Nusco
- Telethon Institute of Genetics and Medicine, Pozzuoli, Italy
| | - Paola Arena
- Telethon Institute of Genetics and Medicine, Pozzuoli, Italy
| | | | - Debora Paris
- Institute of Biomolecular Chemistry, National Research Council, Pozzuoli, Italy
| | - Paola Cuomo
- Institute of Biomolecular Chemistry, National Research Council, Pozzuoli, Italy
| | - Andrea Motta
- Institute of Biomolecular Chemistry, National Research Council, Pozzuoli, Italy
| | - Matthew Nitzahn
- Molecular Biology Institute, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Gerald S Lipshutz
- Molecular Biology Institute, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
- Surgery, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Ainhoa Martínez-Pizarro
- Centro de Biología Molecular Severo Ochoa UAM-CSIC, CIBERER, IdiPaz, Universidad Autónoma, Madrid, Spain
| | - Eva Richard
- Centro de Biología Molecular Severo Ochoa UAM-CSIC, CIBERER, IdiPaz, Universidad Autónoma, Madrid, Spain
| | - Lourdes R Desviat
- Centro de Biología Molecular Severo Ochoa UAM-CSIC, CIBERER, IdiPaz, Universidad Autónoma, Madrid, Spain
| | - Johannes Häberle
- Division of Metabolism and Children's Research Center, University Children's Hospital, Zurich, Switzerland
| | | | - Nicola Brunetti-Pierri
- Telethon Institute of Genetics and Medicine, Pozzuoli, Italy.
- Department of Translational Medicine, Federico II University, Naples, Italy.
- Scuola Superiore Meridionale (SSM, School of Advanced Studies), Genomics and Experimental Medicine Program, University of Naples Federico II, Naples, Italy.
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5
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Yang Z, Stemmer PM, Petriello MC. Proteomics-Based Identification of Interaction Partners of the Xenobiotic Detoxification Enzyme FMO3 Reveals Involvement in Urea Cycle. TOXICS 2022; 10:60. [PMID: 35202247 PMCID: PMC8877285 DOI: 10.3390/toxics10020060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 01/18/2022] [Accepted: 01/25/2022] [Indexed: 02/06/2023]
Abstract
The hepatic xenobiotic metabolizing enzyme flavin-containing monooxygenase 3 (FMO3) has been implicated in the development of cardiometabolic disease primarily due to its enzymatic product trimethylamine-N oxide (TMAO), which has recently been shown to be associated with multiple chronic diseases, including kidney and coronary artery diseases. Although TMAO may have causative roles as a pro-inflammatory mediator, the possibility for roles in metabolic disease for FMO3, irrespective of TMAO formation, does exist. We hypothesized that FMO3 may interact with other proteins known to be involved in cardiometabolic diseases and that modulating the expression of FMO3 may impact on these interaction partners. Here, we combine a co-immunoprecipitation strategy coupled to unbiased proteomic workflow to report a novel protein:protein interaction network for FMO3. We identified 51 FMO3 protein interaction partners, and through gene ontology analysis, have identified urea cycle as an enriched pathway. Using mice deficient in FMO3 on two separate backgrounds, we validated and further investigated expressional and functional associations between FMO3 and the identified urea cycle genes. FMO3-deficient mice showed hepatic overexpression of carbamoylphosphate synthetase (CPS1), the rate-limiting gene of urea cycle, and increased hepatic urea levels, especially in mice of FVB (Friend leukemia virus B strain) background. Finally, overexpression of FMO3 in murine AML12 hepatocytes led to downregulation of CPS1. Although there is past literature linking TMAO to urea cycle, this is the first published work showing that FMO3 and CPS1 may directly interact, implicating a role for FMO3 in chronic kidney disease irrespective of TMAO formation.
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Affiliation(s)
- Zhao Yang
- Institute of Environmental Health Sciences, Wayne State University, Detroit, MI 48202, USA; (Z.Y.); (P.M.S.)
| | - Paul M. Stemmer
- Institute of Environmental Health Sciences, Wayne State University, Detroit, MI 48202, USA; (Z.Y.); (P.M.S.)
- Department of Pharmaceutical Sciences, College of Pharmacy, Wayne State University, Detroit, MI 48202, USA
| | - Michael C. Petriello
- Institute of Environmental Health Sciences, Wayne State University, Detroit, MI 48202, USA; (Z.Y.); (P.M.S.)
- Department of Pharmacology, School of Medicine, Wayne State University, Detroit, MI 48202, USA
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6
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Rosier K, McDevitt MT, Smet J, Floyd BJ, Verschoore M, Marcaida MJ, Bingman CA, Lemmens I, Dal Peraro M, Tavernier J, Cravatt BF, Gounko NV, Vints K, Monnens Y, Bhalla K, Aerts L, Rashan EH, Vanlander AV, Van Coster R, Régal L, Pagliarini DJ, Creemers JW. Prolyl endopeptidase-like is a (thio)esterase involved in mitochondrial respiratory chain function. iScience 2021; 24:103460. [PMID: 34888501 PMCID: PMC8634043 DOI: 10.1016/j.isci.2021.103460] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 10/27/2021] [Accepted: 11/11/2021] [Indexed: 11/25/2022] Open
Abstract
Deficiency of the serine hydrolase prolyl endopeptidase-like (PREPL) causes a recessive metabolic disorder characterized by neonatal hypotonia, feeding difficulties, and growth hormone deficiency. The pathophysiology of PREPL deficiency and the physiological substrates of PREPL remain largely unknown. In this study, we connect PREPL with mitochondrial gene expression and oxidative phosphorylation by analyzing its protein interactors. We demonstrate that the long PREPLL isoform localizes to mitochondria, whereas PREPLS remains cytosolic. Prepl KO mice showed reduced mitochondrial complex activities and disrupted mitochondrial gene expression. Furthermore, mitochondrial ultrastructure was abnormal in a PREPL-deficient patient and Prepl KO mice. In addition, we reveal that PREPL has (thio)esterase activity and inhibition of PREPL by Palmostatin M suggests a depalmitoylating function. We subsequently determined the crystal structure of PREPL, thereby providing insight into the mechanism of action. Taken together, PREPL is a (thio)esterase rather than a peptidase and PREPLL is involved in mitochondrial homeostasis.
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Affiliation(s)
- Karen Rosier
- Laboratory for Biochemical Neuroendocrinology, Department of Human Genetics, KU Leuven, Leuven, Belgium
| | - Molly T. McDevitt
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Joél Smet
- Department of Internal Medicine and Pediatrics, Division of Pediatric Neurology and Metabolism, Ghent University Hospital, Ghent, Belgium
| | - Brendan J. Floyd
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Maxime Verschoore
- Department of Internal Medicine and Pediatrics, Division of Pediatric Neurology and Metabolism, Ghent University Hospital, Ghent, Belgium
| | - Maria J. Marcaida
- Institute of Bioengineering, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Craig A. Bingman
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Irma Lemmens
- Center for Medical Biotechnology, VIB, Department of Biomolecular Medicine, Ghent University, Ghent, Belgium
| | - Matteo Dal Peraro
- Institute of Bioengineering, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Jan Tavernier
- Center for Medical Biotechnology, VIB, Department of Biomolecular Medicine, Ghent University, Ghent, Belgium
| | - Benjamin F. Cravatt
- The Department of Chemistry and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Natalia V. Gounko
- VIB-KU Leuven Center for Brain & Disease Research, Electron Microscopy Platform & VIB-Bioimaging Core, Leuven, Belgium
- Department of Neurosciences, Leuven Brain Institute, KU Leuven, Leuven, Belgium
| | - Katlijn Vints
- VIB-KU Leuven Center for Brain & Disease Research, Electron Microscopy Platform & VIB-Bioimaging Core, Leuven, Belgium
- Department of Neurosciences, Leuven Brain Institute, KU Leuven, Leuven, Belgium
| | - Yenthe Monnens
- Laboratory for Biochemical Neuroendocrinology, Department of Human Genetics, KU Leuven, Leuven, Belgium
| | - Kritika Bhalla
- Laboratory for Biochemical Neuroendocrinology, Department of Human Genetics, KU Leuven, Leuven, Belgium
| | - Laetitia Aerts
- Laboratory for Biochemical Neuroendocrinology, Department of Human Genetics, KU Leuven, Leuven, Belgium
| | - Edrees H. Rashan
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Arnaud V. Vanlander
- Department of Internal Medicine and Pediatrics, Division of Pediatric Neurology and Metabolism, Ghent University Hospital, Ghent, Belgium
| | - Rudy Van Coster
- Department of Internal Medicine and Pediatrics, Division of Pediatric Neurology and Metabolism, Ghent University Hospital, Ghent, Belgium
| | - Luc Régal
- Laboratory for Biochemical Neuroendocrinology, Department of Human Genetics, KU Leuven, Leuven, Belgium
- Department of Pediatrics, Pediatric Neurology and Metabolism, UZ Brussel, Brussels, Belgium
| | - David J. Pagliarini
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
- Morgridge Institute for Research, Madison, WI 53715, USA
- Departments of Cell Biology and Physiology, Biochemistry and Molecular Biophysics, and Genetics, Washington University School of Medicine, St Louis, MO 63110, USA
| | - John W.M. Creemers
- Laboratory for Biochemical Neuroendocrinology, Department of Human Genetics, KU Leuven, Leuven, Belgium
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7
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Ribas GS, Lopes FF, Deon M, Vargas CR. Hyperammonemia in Inherited Metabolic Diseases. Cell Mol Neurobiol 2021; 42:2593-2610. [PMID: 34665389 DOI: 10.1007/s10571-021-01156-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Accepted: 10/10/2021] [Indexed: 12/13/2022]
Abstract
Ammonia is a neurotoxic compound which is detoxified through liver enzymes from urea cycle. Several inherited or acquired conditions can elevate ammonia concentrations in blood, causing severe damage to the central nervous system due to the toxic effects exerted by ammonia on the astrocytes. Therefore, hyperammonemic patients present potentially life-threatening neuropsychiatric symptoms, whose severity is related with the hyperammonemia magnitude and duration, as well as the brain maturation stage. Inherited metabolic diseases caused by enzymatic defects that compromise directly or indirectly the urea cycle activity are the main cause of hyperammonemia in the neonatal period. These diseases are mainly represented by the congenital defects of urea cycle, classical organic acidurias, and the defects of mitochondrial fatty acids oxidation, with hyperammonemia being more severe and frequent in the first two groups mentioned. An effective and rapid treatment of hyperammonemia is crucial to prevent irreversible neurological damage and it depends on the understanding of the pathophysiology of the diseases, as well as of the available therapeutic approaches. In this review, the mechanisms underlying the hyperammonemia and neurological dysfunction in urea cycle disorders, organic acidurias, and fatty acids oxidation defects, as well as the therapeutic strategies for the ammonia control will be discussed.
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Affiliation(s)
- Graziela Schmitt Ribas
- Departamento de Análises Clínicas, Faculdade de Farmácia, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil. .,Serviço de Genética Médica, Hospital de Clíınicas de Porto Alegre, Ramiro Barcelos, 2350, Porto Alegre, RS, CEP 90035-003, Brazil.
| | - Franciele Fátima Lopes
- Serviço de Genética Médica, Hospital de Clíınicas de Porto Alegre, Ramiro Barcelos, 2350, Porto Alegre, RS, CEP 90035-003, Brazil
| | - Marion Deon
- Serviço de Genética Médica, Hospital de Clíınicas de Porto Alegre, Ramiro Barcelos, 2350, Porto Alegre, RS, CEP 90035-003, Brazil
| | - Carmen Regla Vargas
- Departamento de Análises Clínicas, Faculdade de Farmácia, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil. .,Serviço de Genética Médica, Hospital de Clíınicas de Porto Alegre, Ramiro Barcelos, 2350, Porto Alegre, RS, CEP 90035-003, Brazil.
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8
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Cao Y, Qiu T, Kathayat RS, Azizi SA, Thorne AK, Ahn D, Fukata Y, Fukata M, Rice PA, Dickinson BC. ABHD10 is an S-depalmitoylase affecting redox homeostasis through peroxiredoxin-5. Nat Chem Biol 2019; 15:1232-1240. [PMID: 31740833 PMCID: PMC6871660 DOI: 10.1038/s41589-019-0399-y] [Citation(s) in RCA: 70] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2019] [Accepted: 09/30/2019] [Indexed: 12/12/2022]
Abstract
S-palmitoylation is a reversible lipid post-translational modification that has been observed on mitochondrial proteins, but both the regulation and functional consequences of mitochondrial S-palmitoylation are poorly understood. Here, we show that perturbing the “erasers” of S-palmitoylation, acyl protein thioesterases (APTs), with either pan-active inhibitors or a new mitochondrial-targeted APT inhibitor, diminishes the antioxidant buffering capacity of mitochondria. Surprisingly, this effect was not mediated by the only known mitochondrial APT, but rather by a resident mitochondrial protein with no known endogenous function, ABHD10. We show that ABHD10 is a new member of the APT family of regulatory proteins and identify peroxiredoxin 5 (PRDX5), a key antioxidant protein, as the first target of ABHD10 S-depalmitoylase activity. We then discover that ABHD10 regulates the S-palmitoylation status of the nucleophilic active site residue of PRDX5, providing a direct mechanistic connection between ABHD10-mediated S-depalmitoylation of PRDX5 and its antioxidant capacity.
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Affiliation(s)
- Yang Cao
- Department of Chemistry, The University of Chicago, Chicago, IL, USA
| | - Tian Qiu
- Department of Chemistry, The University of Chicago, Chicago, IL, USA
| | - Rahul S Kathayat
- Department of Chemistry, The University of Chicago, Chicago, IL, USA
| | - Saara-Anne Azizi
- Department of Chemistry, The University of Chicago, Chicago, IL, USA.,Medical Scientist Training Program, Pritzker School of Medicine, The University of Chicago, Chicago, IL, USA
| | - Anneke K Thorne
- Department of Chemistry, The University of Chicago, Chicago, IL, USA
| | - Daniel Ahn
- Department of Chemistry, The University of Chicago, Chicago, IL, USA
| | - Yuko Fukata
- Division of Membrane Physiology, Department of Molecular and Cellular Physiology, National Institute for Physiological Sciences, National Institutes of Natural Sciences, Okazaki, Japan
| | - Masaki Fukata
- Division of Membrane Physiology, Department of Molecular and Cellular Physiology, National Institute for Physiological Sciences, National Institutes of Natural Sciences, Okazaki, Japan
| | - Phoebe A Rice
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, USA
| | - Bryan C Dickinson
- Department of Chemistry, The University of Chicago, Chicago, IL, USA.
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9
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Palmitoylation in apicomplexan parasites: from established regulatory roles to putative new functions. Mol Biochem Parasitol 2019; 230:16-23. [PMID: 30978365 DOI: 10.1016/j.molbiopara.2019.04.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Revised: 03/17/2019] [Accepted: 04/07/2019] [Indexed: 01/28/2023]
Abstract
This minireview aims to provide a comprehensive synthesis on protein palmitoylation in apicomplexan parasites and higher eukaryotes where most of the data is available. Apicomplexan parasites encompass numerous obligate intracellular parasites with significant health risk to animals and humans. Protein palmitoylation is a widespread post-translational modification that plays important regulatory roles in several physiological and pathological states. Functional studies demonstrate that many processes important for parasites are regulated by protein palmitoylation. Structural analyses suggest that enzymes responsible for the palmitoylation process have a conserved architecture in eukaryotes although there are particular differences which could be related to their substrate specificities. Interestingly, with the publication of T. gondii and P. falciparum palmitoylomes new possible regulatory functions are unveiled. Here we focus our discussion on data from both palmitoylomes that suggest that palmitoylation of nuclear proteins regulate different chromatin-related processes such as nucleosome assembly and stability, transcription, translation and DNA repair.
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10
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Tang M, Lu L, Huang Z, Chen L. Palmitoylation signaling: a novel mechanism of mitochondria dynamics and diverse pathologies. Acta Biochim Biophys Sin (Shanghai) 2018; 50:831-833. [PMID: 29924300 DOI: 10.1093/abbs/gmy065] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Indexed: 02/01/2023] Open
Affiliation(s)
- Mingzhu Tang
- Institute of Pharmacy and Pharmacology, Learning Key Laboratory for Pharmacoproteomics, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang, China
| | - Liqun Lu
- Institute of Pharmacy and Pharmacology, Learning Key Laboratory for Pharmacoproteomics, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang, China
| | - Zhen Huang
- Institute of Pharmacy and Pharmacology, Learning Key Laboratory for Pharmacoproteomics, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang, China
| | - Linxi Chen
- Institute of Pharmacy and Pharmacology, Learning Key Laboratory for Pharmacoproteomics, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang, China
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11
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Zaballa ME, van der Goot FG. The molecular era of protein S-acylation: spotlight on structure, mechanisms, and dynamics. Crit Rev Biochem Mol Biol 2018; 53:420-451. [DOI: 10.1080/10409238.2018.1488804] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- María-Eugenia Zaballa
- Global Health Institute, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - F. Gisou van der Goot
- Global Health Institute, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
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12
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Nievas YR, Vashisht AA, Corvi MM, Metz S, Johnson PJ, Wohlschlegel JA, de Miguel N. Protein Palmitoylation Plays an Important Role in Trichomonas vaginalis Adherence. Mol Cell Proteomics 2018; 17:2229-2241. [PMID: 29444981 DOI: 10.1074/mcp.ra117.000018] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 01/03/2018] [Indexed: 01/16/2023] Open
Abstract
The flagellated protozoan parasite Trichomonas vaginalis is the etiologic agent of trichomoniasis, the most common non-viral sexually transmitted infection worldwide. As an obligate extracellular pathogen, adherence to epithelial cells is critical for parasite survival within the human host and a better understanding of this process is a prerequisite for the development of therapies to combat infection. In this sense, recent work has shown S-acylation as a key modification that regulates pathogenesis in different protozoan parasites. However, there are no reports indicating whether this post-translational modification is a mechanism operating in T. vaginalis In order to study the extent and function of S-acylation in T. vaginalis biology, we undertook a proteomic study to profile the full scope of S-acylated proteins in this parasite and reported the identification of 363 proteins involved in a variety of biological processes such as protein transport, pathogenesis related and signaling, among others. Importantly, treatment of parasites with the palmitoylation inhibitor 2-bromopalmitate causes a significant decrease in parasite: parasite aggregation as well as adherence to host cells suggesting that palmitoylation could be modifying proteins that are key regulators of Trichomonas vaginalis pathogenesis.
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Affiliation(s)
- Yesica R Nievas
- From the ‡Laboratorio de Parásitos Anaerobios, Instituto de Investigaciones Biotecnológicas-Instituto Tecnológico Chascomús (IIB-INTECH), CONICET-UNSAM, Chascomús B7130IWA, Argentina
| | - Ajay A Vashisht
- §Department of Biological Chemistry, University of California, Los Angeles, California, 90095-1489
| | - Maria M Corvi
- ¶Laboratorio de Bioquímica de Parásitos, Instituto de Investigaciones Biotecnológicas-Instituto Tecnológico Chascomús (IIB-INTECH), CONICET-UNSAM, Chascomús B7130IWA, Argentina
| | - Sebastian Metz
- From the ‡Laboratorio de Parásitos Anaerobios, Instituto de Investigaciones Biotecnológicas-Instituto Tecnológico Chascomús (IIB-INTECH), CONICET-UNSAM, Chascomús B7130IWA, Argentina
| | - Patricia J Johnson
- ‖Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, California, 90095-1489
| | - James A Wohlschlegel
- §Department of Biological Chemistry, University of California, Los Angeles, California, 90095-1489
| | - Natalia de Miguel
- From the ‡Laboratorio de Parásitos Anaerobios, Instituto de Investigaciones Biotecnológicas-Instituto Tecnológico Chascomús (IIB-INTECH), CONICET-UNSAM, Chascomús B7130IWA, Argentina;
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13
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Active and dynamic mitochondrial S-depalmitoylation revealed by targeted fluorescent probes. Nat Commun 2018; 9:334. [PMID: 29362370 PMCID: PMC5780395 DOI: 10.1038/s41467-017-02655-1] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Accepted: 12/18/2017] [Indexed: 01/25/2023] Open
Abstract
The reversible modification of cysteine residues by thioester formation with palmitate (S-palmitoylation) is an abundant lipid post-translational modification (PTM) in mammalian systems. S-palmitoylation has been observed on mitochondrial proteins, providing an intriguing potential connection between metabolic lipids and mitochondrial regulation. However, it is unknown whether and/or how mitochondrial S-palmitoylation is regulated. Here we report the development of mitoDPPs, targeted fluorescent probes that measure the activity levels of “erasers” of S-palmitoylation, acyl-protein thioesterases (APTs), within mitochondria of live cells. Using mitoDPPs, we discover active S-depalmitoylation in mitochondria, in part mediated by APT1, an S-depalmitoylase previously thought to reside in the cytosol and on the Golgi apparatus. We also find that perturbation of long-chain acyl-CoA cytoplasm and mitochondrial regulatory proteins, respectively, results in selective responses from cytosolic and mitochondrial S-depalmitoylases. Altogether, this work reveals that mitochondrial S-palmitoylation is actively regulated by “eraser” enzymes that respond to alterations in mitochondrial lipid homeostasis. S-palmitoylation regulation has been studied mostly in the cytosol and its role in mitochondria is unclear. Here the authors develop fluorescent mitochondria-targeted probes and find that depalmitoylation occurs in mitochondria and it’s influenced by alterations in mitochondrial lipid homeostasis.
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14
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Brain and the Liver: Cerebral Edema, Hepatic Encephalopathy and Beyond. HEPATIC CRITICAL CARE 2018. [PMCID: PMC7122599 DOI: 10.1007/978-3-319-66432-3_8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Occurrence of brain dysfunction is common in both chronic liver disease as well as acute liver failure. While brain dysfunction most commonly manifests as hepatic encephalopathy is chronic liver disease; devastating complications of cerebral edema and brain herniation syndromes may occur with acute liver failure. Ammonia seems to play a central role in the pathogenesis of brain dysfunction in both chronic liver disease and acute liver failure. In this chapter we outline the pathophysiology and clinical management of brain dysfunction in the critically ill patients with liver disease.
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Shen LF, Chen YJ, Liu KM, Haddad ANS, Song IW, Roan HY, Chen LY, Yen JJY, Chen YJ, Wu JY, Chen YT. Role of S-Palmitoylation by ZDHHC13 in Mitochondrial function and Metabolism in Liver. Sci Rep 2017; 7:2182. [PMID: 28526873 PMCID: PMC5438363 DOI: 10.1038/s41598-017-02159-4] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Accepted: 04/12/2017] [Indexed: 11/17/2022] Open
Abstract
Palmitoyltransferase (PAT) catalyses protein S-palmitoylation which adds 16-carbon palmitate to specific cysteines and contributes to various biological functions. We previously reported that in mice, deficiency of Zdhhc13, a member of the PAT family, causes severe phenotypes including amyloidosis, alopecia, and osteoporosis. Here, we show that Zdhhc13 deficiency results in abnormal liver function, lipid abnormalities, and hypermetabolism. To elucidate the molecular mechanisms underlying these disease phenotypes, we applied a site-specific quantitative approach integrating an alkylating resin-assisted capture and mass spectrometry-based label-free strategy for studying the liver S-palmitoylome. We identified 2,190 S-palmitoylated peptides corresponding to 883 S-palmitoylated proteins. After normalization using the membrane proteome with TMT10-plex labelling, 400 (31%) of S-palmitoylation sites on 254 proteins were down-regulated in Zdhhc13-deficient mice, representing potential ZDHHC13 substrates. Among these, lipid metabolism and mitochondrial dysfunction proteins were overrepresented. MCAT and CTNND1 were confirmed to be specific ZDHHC13 substrates. Furthermore, we found impaired mitochondrial function in hepatocytes of Zdhhc13-deficient mice and Zdhhc13-knockdown Hep1–6 cells. These results indicate that ZDHHC13 is an important regulator of mitochondrial activity. Collectively, our study allows for a systematic view of S-palmitoylation for identification of ZDHHC13 substrates and demonstrates the role of ZDHHC13 in mitochondrial function and metabolism in liver.
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Affiliation(s)
- Li-Fen Shen
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Yi-Ju Chen
- Institute of Chemistry, Academia Sinica, Taipei, Taiwan
| | - Kai-Ming Liu
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Amir N Saleem Haddad
- Department of Biology, University of Toronto Mississauga, Mississauga, Ontario, Canada
| | - I-Wen Song
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Hsiao-Yuh Roan
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Li-Ying Chen
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Jeffrey J Y Yen
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Yu-Ju Chen
- Institute of Chemistry, Academia Sinica, Taipei, Taiwan
| | - Jer-Yuarn Wu
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Yuan-Tsong Chen
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan. .,Department of Pediatrics, Duke University Medical Center, Durham, North Carolina, United States of America.
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16
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Identification of new palmitoylated proteins in Toxoplasma gondii. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2016; 1864:400-8. [PMID: 26825284 DOI: 10.1016/j.bbapap.2016.01.010] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Revised: 12/15/2015] [Accepted: 01/04/2016] [Indexed: 01/23/2023]
Abstract
Protein palmitoylation has been shown to be an important post-translational modification in eukaryotic cells. This modification alters the localization and/or the function of the targeted protein. In recent years, protein palmitoylation has risen in importance in apicomplexan parasites as well. In Toxoplasma gondii, some proteins have been reported to be modified by palmitate. With the development of new techniques that allow the isolation of palmitoylated proteins, this significant post-translational modification has begun to be studied in more detail in T. gondii. Here we describe the palmitoylome of the tachyzoite stage of T. gondii using a combination of the acyl-biotin exchange chemistry method and mass spectrometry analysis. We identified 401 proteins found in multiple cellular compartments, with a wide range of functions that vary from metabolic processes, gliding and host-cell invasion to even regulation of transcription and translation. Besides, we found that more rhoptry proteins than the ones already described for Toxoplasma are palmitoylated, suggesting an important role for this modification in the invasion mechanism of the host-cell. This study documents that protein palmitoylation is a common modification in T. gondii that could have an impact on different cellular processes.
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Segal-Salto M, Sapir T, Reiner O. Reversible Cysteine Acylation Regulates the Activity of Human Palmitoyl-Protein Thioesterase 1 (PPT1). PLoS One 2016; 11:e0146466. [PMID: 26731412 PMCID: PMC4701722 DOI: 10.1371/journal.pone.0146466] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Accepted: 12/17/2015] [Indexed: 01/24/2023] Open
Abstract
Mutations in the depalmitoylating enzyme gene, PPT1, cause the infantile form of Neuronal Ceroid Lipofuscinosis (NCL), an early onset neurodegenerative disease. During recent years there have been different therapeutic attempts including enzyme replacement. Here we show that PPT1 is palmitoylated in vivo and is a substrate for two palmitoylating enzymes, DHHC3 and DHHC7. The palmitoylated protein is detected in both cell lysates and medium. The presence of PPT1 with palmitoylated signal peptide in the cell medium suggests that a subset of the protein is secreted by a nonconventional mechanism. Using a mutant form of PPT1, C6S, which was not palmitoylated, we further demonstrate that palmitoylation does not affect intracellular localization but rather that the unpalmitoylated form enhanced the depalmitoylation activity of the protein. The calculated Vmax of the enzyme was significantly affected by the palmitoylation, suggesting that the addition of a palmitate group is reminiscent of adding a noncompetitive inhibitor. Thus, we reveal the existence of a positive feedback loop, where palmitoylation of PPT1 results in decreased activity and subsequent elevation in the amount of palmitoylated proteins. This positive feedback loop is likely to initiate a vicious cycle, which will enhance disease progression. The understanding of this process may facilitate enzyme replacement strategies.
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Affiliation(s)
- Michal Segal-Salto
- The Department of Molecular Genetics, Weizmann Institute of Science, 76100 Rehovot, Israel
| | - Tamar Sapir
- The Department of Molecular Genetics, Weizmann Institute of Science, 76100 Rehovot, Israel
| | - Orly Reiner
- The Department of Molecular Genetics, Weizmann Institute of Science, 76100 Rehovot, Israel
- * E-mail:
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18
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Nohara K, Shin Y, Park N, Jeong K, He B, Koike N, Yoo SH, Chen Z. Ammonia-lowering activities and carbamoyl phosphate synthetase 1 (Cps1) induction mechanism of a natural flavonoid. Nutr Metab (Lond) 2015; 12:23. [PMID: 26075008 PMCID: PMC4465466 DOI: 10.1186/s12986-015-0020-7] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Accepted: 06/04/2015] [Indexed: 12/30/2022] Open
Abstract
OBJECTIVE Ammonia detoxification is essential for physiological well-being, and the urea cycle in liver plays a predominant role in ammonia disposal. Nobiletin (NOB), a natural dietary flavonoid, is known to exhibit various physiological efficacies. In the current study, we investigated a potential role of NOB in ammonia control and the underlying cellular mechanism. MATERIALS/METHODS C57BL/6 mice were fed with regular chow (RC), high-fat (HFD) or high-protein diet (HPD) and treated with either vehicle or NOB. Serum and/or urine levels of ammonia and urea were measured. Liver expression of genes encoding urea cycle enzymes and C/EBP transcription factors was determined over the circadian cycle. Luciferase reporter assays were carried out to investigate function of CCAAT consensus elements on the carbamoyl phosphate synthetase (Cps1) gene promoter. A circadian clock-deficient mouse mutant, Clock (Δ19/Δ19) , was utilized to examine a requisite role of the circadian clock in mediating NOB induction of Cps1. RESULTS NOB was able to lower serum ammonia levels in mice fed with RC, HFD or HPD. Compared with RC, HFD repressed the mRNA and protein expression of Cps1, encoding the rate-limiting enzyme of the urea cycle. Interestingly, NOB rescued CPS1 protein levels under the HFD condition via induction of the transcription factors C/EBPα and C/EBPβ. Expression of other urea cycle genes was also decreased by HFD relative to RC and again restored by NOB to varying degrees, which, in conjunction with Cps1 promoter reporter analysis, suggested a C/EBP-dependent mechanism for the co-induction of urea cycle genes by NOB. In comparison, HPD markedly increased CPS1 levels relative to RC, yet NOB did not further enrich CPS1 to a significant extent. Using the circadian mouse mutant Clock (Δ19/Δ19) , we also showed that a functional circadian clock, known to modulate C/EBP and CPS1 expression, was required for NOB induction of CPS1 under the HFD condition. CONCLUSION NOB, a dietary flavonoid, exhibits a broad activity in ammonia control across varying diets, and regulates urea cycle function via C/EBP-and clock-dependent regulatory mechanisms.
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Affiliation(s)
- Kazunari Nohara
- Department of Biochemistry and Molecular Biology, The University of Texas Health Science Center at Houston, 6431 Fannin Street, MSB 6.200, Houston, TX 77030 USA
| | - Youngmin Shin
- Department of Biochemistry and Molecular Biology, The University of Texas Health Science Center at Houston, 6431 Fannin Street, MSB 6.200, Houston, TX 77030 USA
| | - Noheon Park
- Department of Neuroscience, The University of Texas Southwestern Medical Center, Dallas, TX 75390 USA
| | - Kwon Jeong
- Department of Biochemistry and Molecular Biology, The University of Texas Health Science Center at Houston, 6431 Fannin Street, MSB 6.200, Houston, TX 77030 USA
| | - Baokun He
- Department of Biochemistry and Molecular Biology, The University of Texas Health Science Center at Houston, 6431 Fannin Street, MSB 6.200, Houston, TX 77030 USA
| | - Nobuya Koike
- Department of Physiology and Systems Bioscience, Kyoto Prefectural University of Medicine, Kyoto, 602-8566 Japan
| | - Seung-Hee Yoo
- Department of Biochemistry and Molecular Biology, The University of Texas Health Science Center at Houston, 6431 Fannin Street, MSB 6.200, Houston, TX 77030 USA
| | - Zheng Chen
- Department of Biochemistry and Molecular Biology, The University of Texas Health Science Center at Houston, 6431 Fannin Street, MSB 6.200, Houston, TX 77030 USA
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Laemmle A, Hahn D, Hu L, Rüfenacht V, Gautschi M, Leibundgut K, Nuoffer JM, Häberle J. Fatal hyperammonemia and carbamoyl phosphate synthetase 1 (CPS1) deficiency following high-dose chemotherapy and autologous hematopoietic stem cell transplantation. Mol Genet Metab 2015; 114:438-44. [PMID: 25639153 DOI: 10.1016/j.ymgme.2015.01.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Revised: 01/19/2015] [Accepted: 01/19/2015] [Indexed: 11/16/2022]
Abstract
Fatal hyperammonemia secondary to chemotherapy for hematological malignancies or following bone marrow transplantation has been described in few patients so far. In these, the pathogenesis of hyperammonemia remained unclear and was suggested to be multifactorial. We observed severe hyperammonemia (maximum 475 μmol/L) in a 2-year-old male patient, who underwent high-dose chemotherapy with carboplatin, etoposide and melphalan, and autologous hematopoietic stem cell transplantation for a neuroblastoma stage IV. Despite intensive care treatment, hyperammonemia persisted and the patient died due to cerebral edema. The biochemical profile with elevations of ammonia and glutamine (maximum 1757 μmol/L) suggested urea cycle dysfunction. In liver homogenates, enzymatic activity and protein expression of the urea cycle enzyme carbamoyl phosphate synthetase 1 (CPS1) were virtually absent. However, no mutation was found in CPS1 cDNA from liver and CPS1 mRNA expression was only slightly decreased. We therefore hypothesized that the acute onset of hyperammonemia was due to an acquired, chemotherapy-induced (posttranscriptional) CPS1 deficiency. This was further supported by in vitro experiments in HepG2 cells treated with carboplatin and etoposide showing a dose-dependent decrease in CPS1 protein expression. Due to severe hyperlactatemia, we analysed oxidative phosphorylation complexes in liver tissue and found reduced activities of complexes I and V, which suggested a more general mitochondrial dysfunction. This study adds to the understanding of chemotherapy-induced hyperammonemia as drug-induced CPS1 deficiency is suggested. Moreover, we highlight the need for urgent diagnostic and therapeutic strategies addressing a possible secondary urea cycle failure in future patients with hyperammonemia during chemotherapy and stem cell transplantation.
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Affiliation(s)
- Alexander Laemmle
- Division of Metabolism and Children's Research Center (CRC), University Children's Hospital, Zurich, Switzerland; Department of Pediatrics, University Children's Hospital, Bern, Switzerland.
| | - Dagmar Hahn
- University Institute of Clinical Chemistry, University of Bern, Switzerland.
| | - Liyan Hu
- Division of Metabolism and Children's Research Center (CRC), University Children's Hospital, Zurich, Switzerland.
| | - Véronique Rüfenacht
- Division of Metabolism and Children's Research Center (CRC), University Children's Hospital, Zurich, Switzerland.
| | - Matthias Gautschi
- Department of Pediatrics, University Children's Hospital, Bern, Switzerland; University Institute of Clinical Chemistry, University of Bern, Switzerland.
| | - Kurt Leibundgut
- Department of Pediatrics, University Children's Hospital, Bern, Switzerland.
| | - Jean-Marc Nuoffer
- Department of Pediatrics, University Children's Hospital, Bern, Switzerland; University Institute of Clinical Chemistry, University of Bern, Switzerland.
| | - Johannes Häberle
- Division of Metabolism and Children's Research Center (CRC), University Children's Hospital, Zurich, Switzerland.
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Merino MC, Zamponi N, Vranych CV, Touz MC, Rópolo AS. Identification of Giardia lamblia DHHC proteins and the role of protein S-palmitoylation in the encystation process. PLoS Negl Trop Dis 2014; 8:e2997. [PMID: 25058047 PMCID: PMC4109852 DOI: 10.1371/journal.pntd.0002997] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2013] [Accepted: 05/23/2014] [Indexed: 12/17/2022] Open
Abstract
Protein S-palmitoylation, a hydrophobic post-translational modification, is performed by protein acyltransferases that have a common DHHC Cys-rich domain (DHHC proteins), and provides a regulatory switch for protein membrane association. In this work, we analyzed the presence of DHHC proteins in the protozoa parasite Giardia lamblia and the function of the reversible S-palmitoylation of proteins during parasite differentiation into cyst. Two specific events were observed: encysting cells displayed a larger amount of palmitoylated proteins, and parasites treated with palmitoylation inhibitors produced a reduced number of mature cysts. With bioinformatics tools, we found nine DHHC proteins, potential protein acyltransferases, in the Giardia proteome. These proteins displayed a conserved structure when compared to different organisms and are distributed in different monophyletic clades. Although all Giardia DHHC proteins were found to be present in trophozoites and encysting cells, these proteins showed a different intracellular localization in trophozoites and seemed to be differently involved in the encystation process when they were overexpressed. dhhc transgenic parasites showed a different pattern of cyst wall protein expression and yielded different amounts of mature cysts when they were induced to encyst. Our findings disclosed some important issues regarding the role of DHHC proteins and palmitoylation during Giardia encystation. Giardiasis is a major cause of non-viral/non-bacterial diarrheal disease worldwide and has been included within the WHO Neglected Disease Initiative since 2004. Infection begins with the ingestion of Giardia lamblia in cyst form, which, after exposure to gastric acid in the host stomach and proteases in the duodenum, gives rise to trophozoites. The inverse process is called encystation and begins when the trophozoites migrate to the lower part of the small intestine where they receive signals that trigger synthesis of the components of the cyst wall. The cyst form enables the parasite to survive in the environment, infect a new host and evade the immune response. In this work, we explored the role of protein S-palmitoylation, a unique reversible post-translational modification, during Giardia encystation, because de novo generation of endomembrane compartments, protein sorting and vesicle fusion occur in this process. Our findings may contribute to the design of therapeutic agents against this important human pathogen.
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Affiliation(s)
- María C. Merino
- Instituto de Investigación Médica Mercedes y Martín Ferreyra, INIMEC – Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional de Córdoba, Córdoba, Argentina
- * E-mail:
| | - Nahuel Zamponi
- Instituto de Investigación Médica Mercedes y Martín Ferreyra, INIMEC – Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Cecilia V. Vranych
- Instituto de Investigación Médica Mercedes y Martín Ferreyra, INIMEC – Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional de Córdoba, Córdoba, Argentina
| | - María C. Touz
- Instituto de Investigación Médica Mercedes y Martín Ferreyra, INIMEC – Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Andrea S. Rópolo
- Instituto de Investigación Médica Mercedes y Martín Ferreyra, INIMEC – Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional de Córdoba, Córdoba, Argentina
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21
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Abstract
The covalent attachment of palmitate to proteins can alter protein-lipid and protein-protein interactions thereby influencing protein function. Palmitoylation is a reversible post-translational modification. Thus, like protein phosphorylation, protein palmitoylation can function in activation-dependent signaling pathways. This review will provide an overview of the mechanisms and regulation of protein palmitoylation and focus on the role of palmitoylation in signal transduction pathways of lymphocytes and platelets.
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Affiliation(s)
- Robert Flaumenhaft
- Beth Israel Deaconess Medical Center, Harvard Medical School, Division of Hemostasis and Thrombosis, Department of Medicine, Boston, MA, 02215, USA.
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Li F, Xu W, Zhao S. Regulatory Roles of Metabolites in Cell Signaling Networks. J Genet Genomics 2013; 40:367-74. [DOI: 10.1016/j.jgg.2013.05.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Revised: 05/21/2013] [Accepted: 05/21/2013] [Indexed: 10/26/2022]
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Son HJ, Ha SC, Hwang EY, Kim EA, Ahn JY, Choi SY, Cho SW. Roles of cysteine residues in the inhibition of human glutamate dehydrogenase by palmitoyl-CoA. BMB Rep 2013; 45:707-12. [PMID: 23261056 PMCID: PMC4133811 DOI: 10.5483/bmbrep.2012.45.12.156] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Human glutamate dehydrogenase isozymes (hGDH1 and hGDH2) have been known to be inhibited by palmitoyl-CoA with a high affinity. In this study, we have performed the cassette mutagenesis at six different Cys residues (Cys59, Cys93, Cys119, Cys201, Cys274, and Cys323) to identify palmitoyl-CoA binding sites within hGDH2. Four cysteine residues at positions of C59, C93, C201, or C274 may be involved, at least in part, in the inhibition of hGDH2 by palmitoyl-CoA. There was a biphasic relationship, depending on the levels of palmitoyl-CoA, between the binding of palmitoyl-CoA and the loss of enzyme activity during the inactivation process. The inhibition of hGDH2 by palmitoyl-CoA was not affected by the allosteric inhibitor GTP. Multiple mutagenesis studies on the hGDH2 are in progress to identify the amino acid residues fully responsible for the inhibition by palmitoyl-CoA. [BMB Reports 2012; 45(12): 707-712]
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Affiliation(s)
- Hyo Jeong Son
- Department of Biochemistry and Molecular Biology, University of Ulsan College of Medicine, Seoul 138-736, Korea
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24
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Häberle J. Clinical and biochemical aspects of primary and secondary hyperammonemic disorders. Arch Biochem Biophys 2013; 536:101-8. [PMID: 23628343 DOI: 10.1016/j.abb.2013.04.009] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2013] [Revised: 04/16/2013] [Accepted: 04/17/2013] [Indexed: 02/08/2023]
Abstract
An increased concentration of ammonia is a non-specific laboratory sign indicating the presence of potentially toxic free ammonia that is not normally removed. This does occur in many different conditions for which hyperammonemia is a surrogate marker. Hyperammonemia can occur due to increased production or impaired detoxification of ammonia and should, if associated with clinical symptoms, be regarded as an emergency. The conditions can be classified into primary or secondary hyperammonemias depending on the underlying pathophysiology. If the urea cycle is directly affected by a defect of any of the involved enzymes or transporters, this results in primary hyperammonemia. If however the function of the urea cycle is inhibited by toxic metabolites or by substrate deficiencies, the situation is described as secondary hyperammonemia. For removal of ammonia, mammals require the action of glutamine synthetase in addition to the urea cycle, in order to ensure lowering of plasma ammonia concentrations to the normal range. Independent of its etiology, hyperammonemia may result in irreversible brain damage if not treated early and thoroughly. Thus, early recognition of a hyperammonemic state and immediate initiation of the specific management are of utmost importance. The main prognostic factors are, irrespective of the underlying cause, the duration of the hyperammonemic coma and the extent of ammonia accumulation. This paper will discuss the biochemical background of primary and secondary hyperammonemia and will give an overview of the various underlying conditions including a brief clinical outline and information on the genetic backgrounds.
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Affiliation(s)
- Johannes Häberle
- Division of Metabolism, University Children's Hospital Zurich, Steinwiesstr. 75, 8032 Zurich, Switzerland.
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25
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De Napoli MG, de Miguel N, Lebrun M, Moreno SNJ, Angel SO, Corvi MM. N-terminal palmitoylation is required for Toxoplasma gondii HSP20 inner membrane complex localization. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1833:1329-37. [PMID: 23485398 DOI: 10.1016/j.bbamcr.2013.02.022] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2012] [Revised: 02/14/2013] [Accepted: 02/19/2013] [Indexed: 12/11/2022]
Abstract
Toxoplasma gondii is an obligate intracellular parasite and the causative agent of toxoplasmosis. Protein palmitoylation is known to play roles in signal transduction and in enhancing the hydrophobicity of proteins thus contributing to their membrane association. Global inhibition of protein palmitoylation has been shown to affect T. gondii physiology and invasion of the host cell. However, the proteins affected by this modification have been understudied. This paper shows that the small heat shock protein 20 from T. gondii (TgHSP20) is synthesized as a mature protein in the cytosol and is palmitoylated in three cysteine residues. However, its localization at the inner membrane complex (IMC) is dependent only on N-terminal palmitoylation. Absence or incomplete N-terminal palmitoylation causes TgHSP20 to partially accumulate in a membranous structure. Interestingly, TgHSP20 palmitoylation is not responsible for its interaction with the daughter cells IMCs. Together, our data describe the importance of palmitoylation in protein targeting to the IMC in T. gondii.
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Affiliation(s)
- M G De Napoli
- Universidad Nacional de San Martín, Consejo Nacional de Investigaciones Científicas y Técnicas, Provincia de Buenos Aires, Argentina
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Protein palmitoylation and pathogenesis in apicomplexan parasites. J Biomed Biotechnol 2012; 2012:483969. [PMID: 23093847 PMCID: PMC3470895 DOI: 10.1155/2012/483969] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2012] [Revised: 07/18/2012] [Accepted: 07/24/2012] [Indexed: 01/02/2023] Open
Abstract
Apicomplexan parasites comprise a broad variety of protozoan parasites, including Toxoplasma gondii, Plasmodium, Eimeria, and Cryptosporidium species. Being intracellular parasites, the success in establishing pathogenesis relies in their ability to infect a host-cell and replicate within it. Protein palmitoylation is known to affect many aspects of cell biology. Furthermore, palmitoylation has recently been shown to affect important processes in T. gondii such as replication, invasion, and gliding. Thus, this paper focuses on the importance of protein palmitoylation in the pathogenesis of apicomplexan parasites.
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Alonso AM, Coceres VM, De Napoli MG, Nieto Guil AF, Angel SO, Corvi MM. Protein palmitoylation inhibition by 2-bromopalmitate alters gliding, host cell invasion and parasite morphology in Toxoplasma gondii. Mol Biochem Parasitol 2012; 184:39-43. [PMID: 22484029 DOI: 10.1016/j.molbiopara.2012.03.006] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2011] [Revised: 03/20/2012] [Accepted: 03/22/2012] [Indexed: 01/07/2023]
Abstract
Protein palmitoylation is the reversible covalent attachment of palmitic acid onto proteins. This post-translational modification has been shown to play a part in diverse processes such as signal transduction, cellular localization and regulation of protein activity. Although many aspects of protein palmitoylation have been identified in mammalian and yeast cells, little is known of this modification in Toxoplasma gondii. In order to determine the functional role of protein palmitoylation in T. gondii, tachyzoites were treated with the palmitoylation inhibitor 2-bromopalmitate (2-BP). Parasites treated with 2-BP displayed a significant increase in non-circular trails which were longer than those trails left by non-treated parasites. Furthermore, 2-BP treatment reduced the invasion process to the host cells. Long-term treatment of intracellular tachyzoites resulted in major changes in parasite morphology and shape in a dose-dependent manner. These results suggest that palmitoylation could be modifying proteins that are key players in gliding, invasion and cytoskeletal proteins in T. gondii.
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Affiliation(s)
- A M Alonso
- Laboratorio de Parasitología Molecular, Instituto de Investigaciones Biotecnológicas-Instituto Tecnológico de Chascomús (IIB-INTECH), UNSAM/CONICET, Chascomus, Argentina
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Wu H, Ge J, Yang PY, Wang J, Uttamchandani M, Yao SQ. A peptide aldehyde microarray for high-throughput profiling of cellular events. J Am Chem Soc 2011; 133:1946-54. [PMID: 21247160 DOI: 10.1021/ja109597v] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Microarrays provide exciting opportunities in the field of large-scale proteomics. With the aim to elucidate enzymatic activity and profiles within native biological samples, we developed a microarray comprising a focused positional-scanning library of enzyme inhibitors. The library was diversified across P(1)-P(4) positions, creating 270 different inhibitor sublibraries which were immobilized onto avidin slides. The peptide aldehyde-based small-molecule microarray (SMM) specifically targeted cysteine proteases, thereby enabling large-scale functional assessment of this subgroup of proteases, within fluorescently labeled samples, including pure proteins, cellular lysates, and infected samples. The arrays were shown to elicit binding fingerprints consistent with those of model proteins, specifically caspases and purified cysteine proteases from parasites (rhodesein and cruzain). When tested against lysates from apoptotic Hela and red blood cells infected with Plasmodium falciparum, clear signatures were obtained that were readily attributable to the activity of constituent proteases within these samples. Characteristic binding profiles were further able to distinguish various stages of the parasite infection in erythrocyte lysates. By converting one of our brightest microarray hits into a probe, putative protein markers were identified and pulled down from within apoptotic Hela lysates, demonstrating the potential of target validation and discovery. Taken together, these results demonstrate the utility of targeted SMMs in dissecting cellular biology in complex proteomic samples.
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Affiliation(s)
- Hao Wu
- Department of Chemistry, 3 Science Drive 3, National University of Singapore, Singapore 117543
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Martin DDO, Beauchamp E, Berthiaume LG. Post-translational myristoylation: Fat matters in cellular life and death. Biochimie 2011; 93:18-31. [PMID: 21056615 DOI: 10.1016/j.biochi.2010.10.018] [Citation(s) in RCA: 152] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2010] [Accepted: 10/23/2010] [Indexed: 01/15/2023]
Abstract
Myristoylation corresponds to the irreversible covalent linkage of the 14-carbon saturated fatty acid, myristic acid, to the N-terminal glycine of many eukaryotic and viral proteins. It is catalyzed by N-myristoyltransferase. Typically, the myristate moiety participates in protein subcellular localization by facilitating protein-membrane interactions as well as protein-protein interactions. Myristoylated proteins are crucial components of a wide variety of functions, which include many signalling pathways, oncogenesis or viral replication. Initially, myristoylation was described as a co-translational reaction that occurs after the removal of the initiator methionine residue. However, it is now well established that myristoylation can also occur post-translationally in apoptotic cells. Indeed, during apoptosis hundreds of proteins are cleaved by caspases and in many cases this cleavage exposes an N-terminal glycine within a cryptic myristoylation consensus sequence, which can be myristoylated. The principal objective of this review is to provide an overview on the implication of myristoylation in health and disease with a special emphasis on post-translational myristoylation. In addition, new advancements in the detection and identification of myristoylated proteins are also briefly reviewed.
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Affiliation(s)
- Dale D O Martin
- Department of Cell Biology, School of Molecular and Systems Medicine, MSB-5-55, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada
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Rawat A, Nagaraj R. Determinants of membrane association in the SH4 domain of Fyn: Roles of N-terminus myristoylation and side-chain thioacylation. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2010; 1798:1854-63. [DOI: 10.1016/j.bbamem.2010.06.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2009] [Revised: 05/13/2010] [Accepted: 06/10/2010] [Indexed: 10/19/2022]
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Kostiuk MA, Keller BO, Berthiaume LG. Palmitoylation of ketogenic enzyme HMGCS2 enhances its interaction with PPARalpha and transcription at the Hmgcs2 PPRE. FASEB J 2010; 24:1914-24. [PMID: 20124434 DOI: 10.1096/fj.09-149765] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Excessive liver production of ketone bodies is one of many metabolic complications that can arise from diabetes, and in severe untreated cases, it can result in ketoacidosis, coma, and death. Mitochondrial HMG-CoA synthase (HMGCS2), the rate-limiting enzyme in ketogenesis, has been shown to interact with PPARalpha and act as a coactivator to up-regulate transcription from the PPRE of its own gene. Although protein palmitoylation is typically a cytosolic process that promotes membrane association, we recently identified 21 palmitoylated proteins in rat liver mitochondria, including HMGCS2. Herein, our data support a mechanism whereby palmitate is first added onto HMGCS2 active site Cys166 and then transacylated to Cys305. Palmitoylation promotes the HMGCS2/PPARalpha interaction, resulting in transcriptional activation from the Hmgcs2 PPRE. These results, together with the fact that 8 of the 21 palmitoylated mitochondrial proteins that we previously identified have nuclear receptor interacting motifs, demonstrate a novel--and perhaps ubiquitous--role for palmitoylation as a modulator of transcription.
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Affiliation(s)
- Morris A Kostiuk
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
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Yap MC, Kostiuk MA, Martin DDO, Perinpanayagam MA, Hak PG, Siddam A, Majjigapu JR, Rajaiah G, Keller BO, Prescher JA, Wu P, Bertozzi CR, Falck JR, Berthiaume LG. Rapid and selective detection of fatty acylated proteins using omega-alkynyl-fatty acids and click chemistry. J Lipid Res 2009; 51:1566-80. [PMID: 20028662 DOI: 10.1194/jlr.d002790] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Progress in understanding the biology of protein fatty acylation has been impeded by the lack of rapid direct detection and identification methods. We first report that a synthetic omega-alkynyl-palmitate analog can be readily and specifically incorporated into GAPDH or mitochondrial 3-hydroxyl-3-methylglutaryl-CoA synthase in vitro and reacted with an azido-biotin probe or the fluorogenic probe 3-azido-7-hydroxycoumarin using click chemistry for rapid detection by Western blotting or flat bed fluorescence scanning. The acylated cysteine residues were confirmed by MS. Second, omega-alkynyl-palmitate is preferentially incorporated into transiently expressed H- or N-Ras proteins (but not nonpalmitoylated K-Ras), compared with omega-alkynyl-myristate or omega-alkynyl-stearate, via an alkali sensitive thioester bond. Third, omega-alkynyl-myristate is specifically incorporated into endogenous co- and posttranslationally myristoylated proteins. The competitive inhibitors 2-bromopalmitate and 2-hydroxymyristate prevented incorporation of omega-alkynyl-palmitate and omega-alkynyl-myristate into palmitoylated and myristoylated proteins, respectively. Labeling cells with omega-alkynyl-palmitate does not affect membrane association of N-Ras. Furthermore, the palmitoylation of endogenous proteins including H- and N-Ras could be easily detected using omega-alkynyl-palmitate as label in cultured HeLa, Jurkat, and COS-7 cells, and, promisingly, in mice. The omega-alkynyl-myristate and -palmitate analogs used with click chemistry and azido-probes will be invaluable to study protein acylation in vitro, in cells, and in vivo.
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Affiliation(s)
- Megan C Yap
- Department of Cell Biology, Faculty of MedicineDentistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada
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Kostiuk MA, Keller BO, Berthiaume LG. Non-radioactive detection of palmitoylated mitochondrial proteins using an azido-palmitate analogue. Methods Enzymol 2009; 457:149-65. [PMID: 19426867 DOI: 10.1016/s0076-6879(09)05009-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
While palmitoylation is typically thought of as a cytosolic process resulting in membrane attachment of the palmitoylated proteins, numerous mitochondrial proteins have been shown to be palmitoylated following in vitro labeling of mitochondria with radioactive or bioorthogonal analogues of fatty acids. The fatty acylation of two liver mitochondrial enzymes, methylmalonyl semialdehyde dehydrogenase and carbamoyl phosphate synthetase 1, has been studied in great detail. In both cases palmitoylation of an active site cysteine residue occurred spontaneously and resulted in inhibition of enzymatic activity, thus, suggesting that palmitoylation may be a direct means to regulate the activity of metabolic enzymes within the mitochondria. The progress of investigators working on protein fatty acylation has long been impeded by the long exposure time required to detect the incorporation of [(3)H]-fatty acids into protein by fluorography (often 1-3 months or more). Significant reduction in exposure times has been achieved by the use of [(125)I]-iodofatty acids but these analogues are also hazardous and not commercially available. Herein, we describe a sensitive chemical labeling method for the detection of palmitoylated mitochondrial proteins. The method uses azido-fatty acid analogues that can be attached to proteins and reacted with tagged phosphines via a modified Staudinger ligation. Recently, we used this labeling method, combined with mass spectrometry analysis of the labeled proteins, to identify 21 palmitoylated proteins from rat liver mitochondria.
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Affiliation(s)
- Morris A Kostiuk
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
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Abstract
Many proteins are S-acylated, affecting their localization and function. Dynamic S-acylation in response to various stimuli has been seen for several proteins in vivo. The regulation of S-acylation is beginning to be elucidated. Proteins can autoacylate or be S-acylated by protein acyl transferases (PATs). Deacylation, on the other hand, is an enzymatic process catalyzed by protein thioesterases (APT1 and PPT1) but only APT1 appears to be involved in the regulation of the reversible S-acylation of cytoplasmic proteins seen in vivo. PPT1, on the other hand, is involved in the lysosomal degradation of S-acylated proteins and PPT1 deficiency causes the disease infant neuronal ceroid lipofuscinosis.
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Affiliation(s)
- Ruth Zeidman
- Molecular Medicine, National Heart & Lung Institute, Sir Alexander Fleming Building, Imperial College London, London, UK
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Hart EJ, Powers-Lee SG. Role of Cys-1327 and Cys-1337 in redox sensitivity and allosteric monitoring in human carbamoyl phosphate synthetase. J Biol Chem 2008; 284:5977-85. [PMID: 19106093 DOI: 10.1074/jbc.m808702200] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Human carbamoyl phosphate synthetase (hCPS) has evolved critical features that allow it to remove excess and potentially neurotoxic ammonia via the urea cycle, including use of only free ammonia as a nitrogen donor, a K(m) for ammonia 100-fold lower than for CPSs that also use glutamine as a nitrogen donor, and required allosteric activation by N-acetylglutamate (AGA), a sensor of excess amino acids. The recent availability of a Schizosaccharomyces pombe expression system for hCPS allowed us to utilize protein engineering approaches to elucidate the distinctive hCPS properties. Although the site of AGA interaction is not defined, it is known that the binding of AGA to CPS leads to a conformational change in which a pair of cysteine side chains become proximate and can then be selectively induced to undergo disulfide bonding. We analyzed the response of hCPS cysteine mutants to thiol-specific reagents and identified Cys-1327 and Cys-1337 as the AGA-responsive proximate cysteines. Possibly two of the features unique to urea-specific CPSs, relative to other CPSs (the conserved Cys-1327/Cys-1337 pair and the occurrence at very high concentrations in the liver mitochondrial matrix) co-evolved to provide buffering against reactive oxygen species. Reciprocal mutation analysis of Escherichia coli CPS (eCPS), creating P909C and G919C and establishing the ability of these engineered cysteine residues to share a disulfide bond, indicated an eCPS conformational change at least partly similar to the hCPS conformational change induced by AGA. These findings strongly suggested an alternative eCPS conformation relative to the single crystal conformation thus far identified.
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Affiliation(s)
- Emily J Hart
- Department of Biology, Northeastern University, Boston, Massachusetts 02115, USA
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Schiller TM, Costanzo JP, Lee RE. Urea production capacity in the wood frog (Rana sylvatica) varies with season and experimentally induced hyperuremia. ACTA ACUST UNITED AC 2008; 309:484-93. [DOI: 10.1002/jez.479] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Hyperammonemic encephalopathy caused by carnitine deficiency. J Gen Intern Med 2008; 23:210-3. [PMID: 18080167 PMCID: PMC2359173 DOI: 10.1007/s11606-007-0473-0] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2007] [Revised: 10/18/2007] [Accepted: 11/20/2007] [Indexed: 10/22/2022]
Abstract
Carnitine is an essential co-factor in fatty acid metabolism. Carnitine deficiency can impair fatty acid oxidation, rarely leading to hyperammonemia and encephalopathy. We present the case of a 35-year-old woman who developed acute mental status changes, asterixis, and diffuse muscle weakness. Her ammonia level was elevated at 276 microg/dL. Traditional ammonia-reducing therapies were initiated, but proved ineffective. Pharmacologic, microbial, and autoimmune causes for the hyperammonemia were excluded. The patient was severely malnourished and her carnitine level was found to be extremely low. After carnitine supplementation, ammonia levels normalized and the patient's mental status returned to baseline. In the setting of refractory hyperammonemia, this case illustrates how careful investigation may reveal a treatable condition.
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Kostiuk MA, Corvi MM, Keller BO, Plummer G, Prescher JA, Hangauer MJ, Bertozzi CR, Rajaiah G, Falck JR, Berthiaume LG. Identification of palmitoylated mitochondrial proteins using a bio-orthogonal azido-palmitate analogue. FASEB J 2007; 22:721-32. [PMID: 17971398 PMCID: PMC2860959 DOI: 10.1096/fj.07-9199com] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Increased levels of circulating saturated free fatty acids, such as palmitate, have been implicated in the etiology of type II diabetes and cancer. In addition to being a constituent of glycerolipids and a source of energy, palmitate also covalently attaches to numerous cellular proteins via a process named palmitoylation. Recognized for its roles in membrane tethering, cellular signaling, and protein trafficking, palmitoylation is also emerging as a potential regulator of metabolism. Indeed, we showed previously that the acylation of two mitochondrial proteins at their active site cysteine residues result in their inhibition. Herein, we sought to identify other palmitoylated proteins in mitochondria using a nonradioactive bio-orthogonal azido-palmitate analog that can be selectively derivatized with various tagged triarylphosphines. Our results show that, like palmitate, incorporation of azido-palmitate occurred on mitochondrial proteins via thioester bonds at sites that could be competed out by palmitoyl-CoA. Using this method, we identified 21 putative palmitoylated proteins in the rat liver mitochondrial matrix, a compartment not recognized for its content in palmitoylated proteins, and confirmed the palmitoylation of newly identified mitochondrial 3-hydroxy-3-methylglutaryl-CoA synthase. We postulate that covalent modification and perhaps inhibition of various mitochondrial enzymes by palmitoyl-CoA could lead to the metabolic impairments found in obesity-related diseases.
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Affiliation(s)
- Morris A Kostiuk
- Department of Cell Biology, University of Alberta, Faculty of Medicine and Dentistry, Edmonton, Alberta, T6G 2H7, Canada
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Abstract
Proteins are covalently modified with a variety of lipids, including fatty acids, isoprenoids, and cholesterol. Lipid modifications play important roles in the localization and function of proteins. The focus of this review is S-palmitoylation, the reversible addition of palmitate and other long-chain fatty acids to proteins at cysteine residues in a variety of sequence contexts. The functional consequences of palmitoylation are diverse. Palmitoylation facilitates the association of proteins with membranes, mediates protein trafficking, and more recently has been appreciated as a regulator of protein stability. Members of a family of integral membrane proteins that harbor a DHHC cysteine-rich domain mediate most cellular palmitoylation events. Here we focus on DHHC proteins that modify Ras proteins in yeast and mammalian cells.
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Affiliation(s)
- Marissa J Nadolski
- Department of Cell Biology and Physiology, Washington University School of Medicine, St Louis, MO, USA
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40
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Abstract
Palmitate modifies both peripheral and integral membrane proteins and its addition can be permanent or transient, which makes it unique among the lipid modifications of proteins. The presence of palmitate on a protein affects how the protein interacts with lipids and proteins in a membrane compartment, and the reversibility of palmitoylation allows different modes of trafficking between membrane compartments. Here, we review recent studies that have provided insights into the mechanisms that mediate the functional consequences of this versatile modification.
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Affiliation(s)
- Maurine E Linder
- Department of Cell Biology and Physiology, Washington University School of Medicine, Box 8228, 660 South Euclid Avenue, St. Louis, Missouri 63110, USA.
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Tucker DE, Stewart A, Nallan L, Bendale P, Ghomashchi F, Gelb MH, Leslie CC. Group IVC cytosolic phospholipase A2gamma is farnesylated and palmitoylated in mammalian cells. J Lipid Res 2005; 46:2122-33. [PMID: 16061942 PMCID: PMC2405939 DOI: 10.1194/jlr.m500230-jlr200] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cytosolic phospholipase A(2)gamma (cPLA(2)gamma) is a member of the group IV family of intracellular phospholipase A(2) enzymes, but unlike the well-studied cPLA(2)alpha, it is constitutively bound to membrane and is calcium independent. cPLA(2)gamma contains a C-terminal CaaX sequence and is radiolabeled by mevalonic acid when expressed in cPLA(2)alpha-deficient immortalized lung fibroblasts (IMLF(-/-)). The radiolabel associated with cPLA(2)gamma was identified as the farnesyl group. The protein farnesyltransferase inhibitor BMS-214662 prevented the incorporation of [(3)H]mevalonic acid into cPLA(2)gamma and partially suppressed serum-stimulated arachidonic acid release from IMLF(-/-) and undifferentiated human skeletal muscle (SkMc) cells overexpressing cPLA(2)gamma, but not from cells overexpressing cPLA(2)alpha. However, BMS-214662 did not alter the amount of cPLA(2)gamma associated with membrane. These results were consistent in COS cells expressing the C538S cPLA(2)gamma prenylation mutant. cPLA(2)gamma also contains a classic myristoylation site and several potential palmitoylation sites and was found to be acylated with oleic and palmitic acids but not myristoylated. Immunofluorescence microscopy revealed that cPLA(2)gamma is associated with mitochondria in IMLF(-/-), SkMc cells, and COS cells.
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Affiliation(s)
- Dawn E. Tucker
- Program in Cell Biology, Department of Pediatrics, National Jewish Medical and Research Center, Denver, CO 80206
| | - Allison Stewart
- Program in Cell Biology, Department of Pediatrics, National Jewish Medical and Research Center, Denver, CO 80206
| | - Laxman Nallan
- Departments of Chemistry and Biochemistry, University of Washington, Seattle, WA 98195
| | - Pravine Bendale
- Departments of Chemistry and Biochemistry, University of Washington, Seattle, WA 98195
| | - Farideh Ghomashchi
- Departments of Chemistry and Biochemistry, University of Washington, Seattle, WA 98195
| | - Michael H. Gelb
- Departments of Chemistry and Biochemistry, University of Washington, Seattle, WA 98195
- To whom correspondence should be addressed. e-mail: (M.H.G.); (C.C.L.)
| | - Christina C. Leslie
- Program in Cell Biology, Department of Pediatrics, National Jewish Medical and Research Center, Denver, CO 80206
- Departments of Pathology and Pharmacology, University of Colorado School of Medicine, Denver, CO 80206
- To whom correspondence should be addressed. e-mail: (M.H.G.); (C.C.L.)
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Roussel D, Dumas JF, Simard G, MALTHIèRY Y, Ritz P. Kinetics and control of oxidative phosphorylation in rat liver mitochondria after dexamethasone treatment. Biochem J 2005; 382:491-9. [PMID: 15175015 PMCID: PMC1133805 DOI: 10.1042/bj20040696] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2004] [Revised: 05/25/2004] [Accepted: 06/03/2004] [Indexed: 01/07/2023]
Abstract
The present investigation was undertaken in order to evaluate the contributions of ATP synthesis and proton leak reactions to the rate of active respiration of liver mitochondria, which is altered following dexamethasone treatment (1.5 mg/kg per day for 5 days). We applied top-down metabolic control analysis and its extension, elasticity analysis, to gain insight into the mechanisms of glucocorticoid regulation of mitochondrial bioenergetics. Liver mitochondria were isolated from dexamethasone-treated, pair-fed and control rats when in a fed or overnight fasted state. Injection of dexamethasone for 5 days resulted in an increase in the fraction of the proton cycle of phosphorylating liver mitochondria, which was associated with a decrease in the efficiency of the mitochondrial oxidative phosphorylation process in liver. This increase in proton leak activity occurred with little change in the mitochondrial membrane potential, despite a significant decrease in the rate of oxidative phosphorylation. Regulation analysis indicates that mitochondrial membrane potential homoeostasis is achieved by equal inhibition of the mitochondrial substrate oxidation and phosphorylation reactions in rats given dexamethasone. Our results also suggest that active liver mitochondria from dexamethasone-treated rats are capable of maintaining phosphorylation flux for cellular purposes, despite an increase in the energetic cost of mitochondrial ATP production due to increased basal proton permeability of the inner membrane. They also provide a complete description of the effects of dexamethasone treatment on liver mitochondrial bioenergetics.
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Affiliation(s)
- Damien Roussel
- Laboratoire de Biochimie et Biologie Moléculaire, INSERM EMI-U 00.18, 4 rue Larrey, F-49033 Angers cedex, France
- To whom correspondence should be addressed (email )
| | - Jean-François Dumas
- Laboratoire de Biochimie et Biologie Moléculaire, INSERM EMI-U 00.18, 4 rue Larrey, F-49033 Angers cedex, France
| | - Gilles Simard
- Laboratoire de Biochimie et Biologie Moléculaire, INSERM EMI-U 00.18, 4 rue Larrey, F-49033 Angers cedex, France
| | - Yves MALTHIèRY
- Laboratoire de Biochimie et Biologie Moléculaire, INSERM EMI-U 00.18, 4 rue Larrey, F-49033 Angers cedex, France
| | - Patrick Ritz
- Laboratoire de Biochimie et Biologie Moléculaire, INSERM EMI-U 00.18, 4 rue Larrey, F-49033 Angers cedex, France
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Abstract
Secreted signaling proteins function in a diverse array of essential patterning events during metazoan development, ranging from embryonic segmentation in insects to neural tube differentiation in vertebrates. These proteins generally are expressed in a localized manner, and they may elicit distinct concentration-dependent responses in the cells of surrounding tissues and structures, thus functioning as morphogens that specify the pattern of cellular responses by their tissue distribution. Given the importance of signal distribution, it is notable that the Hedgehog (Hh) and Wnt proteins, two of the most important families of such signals, are known to be covalently modified by lipid moieties, the membrane-anchoring properties of which are not consistent with passive models of protein mobilization within tissues. This review focuses on the mechanisms underlying biogenesis of the mature Hh proteins, which are dually modified by cholesteryl and palmitoyl adducts, as well as on the relationship between Hh proteins and the self-splicing proteins (i.e., proteins containing inteins) and the Hh-like proteins of nematodes. We further discuss the cellular mechanisms that have evolved to handle lipidated Hh proteins in the spatial deployment of the signal in developing tissues and the more recent findings that implicate palmitate modification as an important feature of Wnt signaling proteins.
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Affiliation(s)
- Randall K Mann
- Department of Molecular Biology and Genetics and Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA.
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Smotrys JE, Linder ME. Palmitoylation of intracellular signaling proteins: regulation and function. Annu Rev Biochem 2004; 73:559-87. [PMID: 15189153 DOI: 10.1146/annurev.biochem.73.011303.073954] [Citation(s) in RCA: 452] [Impact Index Per Article: 22.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Protein S-palmitoylation is the thioester linkage of long-chain fatty acids to cysteine residues in proteins. Addition of palmitate to proteins facilitates their membrane interactions and trafficking, and it modulates protein-protein interactions and enzyme activity. The reversibility of palmitoylation makes it an attractive mechanism for regulating protein activity, and this feature has generated intensive investigation of this modification. The regulation of palmitoylation occurs through the actions of protein acyltransferases and protein acylthioesterases. Identification of the protein acyltransferases Erf2/Erf4 and Akr1 in yeast has provided new insight into the palmitoylation reaction. These molecules work in concert with thioesterases, such as acyl-protein thioesterase 1, to regulate the palmitoylation status of numerous signaling molecules, ultimately influencing their function. This review discusses the function and regulation of protein palmitoylation, focusing on intracellular proteins that participate in cell signaling or protein trafficking.
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Affiliation(s)
- Jessica E Smotrys
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
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Lucero HA, Robbins PW. Lipid rafts-protein association and the regulation of protein activity. Arch Biochem Biophys 2004; 426:208-24. [PMID: 15158671 DOI: 10.1016/j.abb.2004.03.020] [Citation(s) in RCA: 143] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2004] [Revised: 03/22/2004] [Indexed: 11/18/2022]
Abstract
Lipid rafts are membrane microdomains enriched in saturated phospholipids, sphingolipids, and cholesterol. They have a varied but distinct protein composition and have been implicated in diverse cellular processes including polarized traffic, signal transduction, endo- and exo-cytoses, entrance of obligate intracellular pathogens, and generation of pathological forms of proteins associated with Alzheimer's and prion diseases. Raft proteins can be permanently or temporarily associated to lipid rafts. Here, we review recent advances on the biochemical and cell biological characterization of rafts, and on the emerging concept of the temporary residency of proteins in rafts as a regulatory mechanism of their biological activity.
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Affiliation(s)
- Héctor A Lucero
- Department of Molecular and Cell Biology, Goldman School of Dental Medicine, Boston University Medical Center, Boston, MA 02118, USA.
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Stöckli J, Rohrer J. The palmitoyltransferase of the cation-dependent mannose 6-phosphate receptor cycles between the plasma membrane and endosomes. Mol Biol Cell 2004; 15:2617-26. [PMID: 15034140 PMCID: PMC420087 DOI: 10.1091/mbc.e03-11-0808] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
The cation-dependent mannose 6-phosphate receptor (CD-MPR) mediates the transport of lysosomal enzymes from the trans-Golgi network to endosomes. Evasion of lysosomal degradation of the CD-MPR requires reversible palmitoylation of a cysteine residue in its cytoplasmic tail. Because palmitoylation is reversible and essential for correct trafficking, it presents a potential regulatory mechanism for the sorting signals within the cytoplasmic domain of the CD-MPR. Characterization of the palmitoylation performing an in vitro palmitoylation assay by using purified full-length CD-MPR revealed that palmitoylation of the CD-MPR occurs enzymatically by a membrane-bound palmitoyltransferase. In addition, analysis of the localization revealed that the palmitoyltransferase cycles between endosomes and the plasma membrane. This was identified by testing fractions from HeLa cell homogenate separated on a density gradient in the in vitro palmitoylation assay and further confirmed by in vivo labeling experiments by using different treatments to block specific protein trafficking steps within the cell. We identified a novel palmitoyltransferase activity in the endocytic pathway responsible for palmitoylation of the CD-MPR. The localization of the palmitoyltransferase not only fulfills the requirement of our hypothesis to be a regulator of the intracellular trafficking of the CD-MPR but also may affect the sorting/activity of other receptors cycling through endosomes.
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47
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Abstract
Since its discovery more than 30 years ago, protein palmitoylation has been shown to have a role in protein-membrane interactions, protein trafficking, and enzyme activity. Until recently, however, the molecular machinery that carries out reversible palmitoylation of proteins has been elusive. In fact, both enzymatic and nonenzymatic S-acylation reaction mechanisms have been proposed. Recent reports of protein palmitoyltransferases in Saccharomyces cerevisiae and Drosophila provide the first glimpse of enzymes that carry out protein palmitoylation. Equally important is the mechanism of depalmitoylation. Two major classes of protein palmitoylthioesterases have been described. One family is lysosomal and is involved in protein degradation. The second is cytosolic and removes palmitoyl moieties preferentially from proteins associated with membranes. This review discusses recent advances in the understanding of mechanisms of addition of palmitate to proteins and removal of palmitate from proteins.
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Affiliation(s)
- Maurine E Linder
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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48
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Abstract
The urea cycle is comprised of five enzymes but also requires other enzymes and mitochondrial amino acid transporters to function fully. The complete urea cycle is expressed in liver and to a small degree also in enterocytes. However, highly regulated expression of several enzymes present in the urea cycle occurs also in many other tissues, where these enzymes are involved in synthesis of nitric oxide, polyamines, proline and glutamate. Glucagon, insulin, and glucocorticoids are major regulators of the expression of urea cycle enzymes in liver. In contrast, the "urea cycle" enzymes in nonhepatic cells are regulated by a wide range of pro- and antiinflammatory cytokines and other agents. Regulation of these enzymes is largely transcriptional in virtually all cell types. This review emphasizes recent information regarding roles and regulation of urea cycle and arginine metabolic enzymes in liver and other cell types.
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Affiliation(s)
- Sidney M Morris
- Department of Molecular Genetics and Biochemistry, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261, USA.
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