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Schempp R, Eilts J, Schöl M, Grijalva Yépez MF, Fekete A, Wigger D, Schumacher F, Kleuser B, van Ham M, Jänsch L, Sauer M, Avota E. The Role of Neutral Sphingomyelinase-2 (NSM2) in the Control of Neutral Lipid Storage in T Cells. Int J Mol Sci 2024; 25:3247. [PMID: 38542220 PMCID: PMC10970209 DOI: 10.3390/ijms25063247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2024] [Revised: 02/25/2024] [Accepted: 03/08/2024] [Indexed: 04/04/2024] Open
Abstract
The accumulation of lipid droplets (LDs) and ceramides (Cer) is linked to non-alcoholic fatty liver disease (NAFLD), regularly co-existing with type 2 diabetes and decreased immune function. Chronic inflammation and increased disease severity in viral infections are the hallmarks of the obesity-related immunopathology. The upregulation of neutral sphingomyelinase-2 (NSM2) has shown to be associated with the pathology of obesity in tissues. Nevertheless, the role of sphingolipids and specifically of NSM2 in the regulation of immune cell response to a fatty acid (FA) rich environment is poorly studied. Here, we identified the presence of the LD marker protein perilipin 3 (PLIN3) in the intracellular nano-environment of NSM2 using the ascorbate peroxidase APEX2-catalyzed proximity-dependent biotin labeling method. In line with this, super-resolution structured illumination microscopy (SIM) shows NSM2 and PLIN3 co-localization in LD organelles in the presence of increased extracellular concentrations of oleic acid (OA). Furthermore, the association of enzymatically active NSM2 with isolated LDs correlates with increased Cer levels in these lipid storage organelles. NSM2 enzymatic activity is not required for NSM2 association with LDs, but negatively affects the LD numbers and cellular accumulation of long-chain unsaturated triacylglycerol (TAG) species. Concurrently, NSM2 expression promotes mitochondrial respiration and fatty acid oxidation (FAO) in response to increased OA levels, thereby shifting cells to a high energetic state. Importantly, endogenous NSM2 activity is crucial for primary human CD4+ T cell survival and proliferation in a FA rich environment. To conclude, our study shows a novel NSM2 intracellular localization to LDs and the role of enzymatically active NSM2 in metabolic response to enhanced FA concentrations in T cells.
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Affiliation(s)
- Rebekka Schempp
- Institute for Virology and Immunobiology, University of Wuerzburg, 97078 Wuerzburg, Germany; (R.S.); (M.S.); (M.F.G.Y.)
| | - Janna Eilts
- Department of Biotechnology and Biophysics, Biocenter, University of Wuerzburg, 97074 Wuerzburg, Germany; (J.E.); (M.S.)
| | - Marie Schöl
- Institute for Virology and Immunobiology, University of Wuerzburg, 97078 Wuerzburg, Germany; (R.S.); (M.S.); (M.F.G.Y.)
| | - Maria Fernanda Grijalva Yépez
- Institute for Virology and Immunobiology, University of Wuerzburg, 97078 Wuerzburg, Germany; (R.S.); (M.S.); (M.F.G.Y.)
| | - Agnes Fekete
- Pharmaceutical Biology, Julius-von-Sachs-Institute, Biocenter, University of Wuerzburg, 97082 Wuerzburg, Germany;
| | - Dominik Wigger
- Department of Pharmacology and Toxicology, Institute of Pharmacy, Freie Universitaet Berlin, 14195 Berlin, Germany; (D.W.); (F.S.); (B.K.)
| | - Fabian Schumacher
- Department of Pharmacology and Toxicology, Institute of Pharmacy, Freie Universitaet Berlin, 14195 Berlin, Germany; (D.W.); (F.S.); (B.K.)
| | - Burkhard Kleuser
- Department of Pharmacology and Toxicology, Institute of Pharmacy, Freie Universitaet Berlin, 14195 Berlin, Germany; (D.W.); (F.S.); (B.K.)
| | - Marco van Ham
- Cellular Proteome Research Group, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany; (M.v.H.); (L.J.)
| | - Lothar Jänsch
- Cellular Proteome Research Group, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany; (M.v.H.); (L.J.)
| | - Markus Sauer
- Department of Biotechnology and Biophysics, Biocenter, University of Wuerzburg, 97074 Wuerzburg, Germany; (J.E.); (M.S.)
| | - Elita Avota
- Institute for Virology and Immunobiology, University of Wuerzburg, 97078 Wuerzburg, Germany; (R.S.); (M.S.); (M.F.G.Y.)
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Allosteric Inhibition of Neutral Sphingomyelinase 2 (nSMase2) by DPTIP: From Antiflaviviral Activity to Deciphering Its Binding Site through In Silico Studies and Experimental Validation. Int J Mol Sci 2022; 23:ijms232213935. [PMID: 36430407 PMCID: PMC9697135 DOI: 10.3390/ijms232213935] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Revised: 11/06/2022] [Accepted: 11/08/2022] [Indexed: 11/16/2022] Open
Abstract
Flavivirus comprises globally emerging and re-emerging pathogens such as Zika virus (ZIKV), Dengue virus (DENV), and West Nile virus (WNV), among others. Although some vaccines are available, there is an unmet medical need as no effective antiviral treatment has been approved for flaviviral infections. The development of host-directed antivirals (HDAs) targeting host factors that are essential for viral replication cycle offers the opportunity for the development of broad-spectrum antivirals. In the case of flaviviruses, recent studies have revealed that neutral sphingomyelinase 2, (nSMase2), involved in lipid metabolism, plays a key role in WNV and ZIKV infection. As a proof of concept, we have determined the antiviral activity of the non-competitive nSMase2 inhibitor DPTIP against WNV and ZIKV virus. DPTIP showed potent antiviral activity with EC50 values of 0.26 µM and 1.56 µM for WNV and ZIKV, respectively. In order to unravel the allosteric binding site of DPTIP in nSMase2 and the details of the interaction, computational studies have been carried out. These studies have revealed that DPTIP could block the DK switch in nSMase2. Moreover, the analysis of the residues contributing to the binding identified His463 as a crucial residue. Interestingly, the inhibitory activity of DPTIP on the H463A mutant protein supported our hypothesis. Thus, an allosteric cavity in nSMase2 has been identified that can be exploited for the development of new inhibitors with anti-flaviviral activity.
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Pavlic A, Bahram Sangani N, Kerins J, Nicolaes G, Schurgers L, Reutelingsperger C. Vascular Smooth Muscle Cell Neutral Sphingomyelinase 2 in the Release of Exosomes and Vascular Calcification. Int J Mol Sci 2022; 23:ijms23169178. [PMID: 36012444 PMCID: PMC9409231 DOI: 10.3390/ijms23169178] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 08/09/2022] [Accepted: 08/12/2022] [Indexed: 12/12/2022] Open
Abstract
Vascular calcification (VC) is the pathological precipitation of calcium salts in the walls of blood vessels. It is a risk factor for cardiovascular events and their associated mortality. VC can be observed in a variety of cardiovascular diseases and is most prominent in diseases that are associated with dysregulated mineral homeostasis such as in chronic kidney disease. Local factors and mechanisms underlying VC are still incompletely understood, but it is appreciated that VC is a multifactorial process in which vascular smooth muscle cells (VSMCs) play an important role. VSMCs participate in VC by releasing extracellular vesicles (EVs), the extent, composition, and propensity to calcify of which depend on VSMC phenotype and microenvironment. Currently, no targeted therapy is available to treat VC. In-depth knowledge of molecular players of EV release and the understanding of their mechanisms constitute a vital foundation for the design of pharmacological treatments to combat VC effectively. This review highlights our current knowledge of VSMCs in VC and focuses on the biogenesis of exosomes and the role of the neutral Sphingomyelinase 2 (nSMase2).
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Affiliation(s)
- Angelina Pavlic
- Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, 6229 ER Maastricht, The Netherlands
| | - Nasim Bahram Sangani
- Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, 6229 ER Maastricht, The Netherlands
| | - Johanna Kerins
- University College Maastricht, Maastricht University, 6229 ER Maastricht, The Netherlands
| | - Gerry Nicolaes
- Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, 6229 ER Maastricht, The Netherlands
| | - Leon Schurgers
- Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, 6229 ER Maastricht, The Netherlands
| | - Chris Reutelingsperger
- Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, 6229 ER Maastricht, The Netherlands
- Correspondence: ; Tel.: +31-43-388-1533
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Yu H, Feng J, Zhong F, Wu Y. Chemical Modification for the "off-/on" Regulation of Enzyme Activity. Macromol Rapid Commun 2022; 43:e2200195. [PMID: 35482602 DOI: 10.1002/marc.202200195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 04/14/2022] [Indexed: 11/07/2022]
Abstract
Enzymes with excellent catalytic performance play important roles in living organisms. Advances in strategies for enzyme chemical modification have enabled powerful strategies for exploring and manipulating enzyme functions and activities. Based on the development of chemical enzyme modifications, incorporating external stimuli-responsive features-for example, responsivity to light, voltage, magnetic force, pH, temperature, redox activity, and small molecules-into a target enzyme to turn "on" and "off" its activity has attracted much attention. The ability to precisely control enzyme activity using different approaches would greatly expand the chemical biology toolbox for clarification and detection of signal transduction and in vivo enzyme function and significantly promote enzyme-based disease therapy. This review summarizes the methods available for chemical enzyme modification mainly for the off-/on control of enzyme activity and particularly highlights the recent progress regarding the applications of this strategy. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Huaibin Yu
- Hubei Engineering Research Center for Biomaterials and Medical Protective Materials, Ministry of Education Key Laboratory of Material Chemistry for Energy Conversion and Storage, Hubei Key Laboratory of Bioinorganic Chemistry & Materia Medica, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology (HUST), 1037 Luoyu Road, Wuhan, 430074, China
| | - Jiayi Feng
- Hubei Engineering Research Center for Biomaterials and Medical Protective Materials, Ministry of Education Key Laboratory of Material Chemistry for Energy Conversion and Storage, Hubei Key Laboratory of Bioinorganic Chemistry & Materia Medica, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology (HUST), 1037 Luoyu Road, Wuhan, 430074, China
| | - Fangrui Zhong
- Hubei Engineering Research Center for Biomaterials and Medical Protective Materials, Ministry of Education Key Laboratory of Material Chemistry for Energy Conversion and Storage, Hubei Key Laboratory of Bioinorganic Chemistry & Materia Medica, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology (HUST), 1037 Luoyu Road, Wuhan, 430074, China
| | - Yuzhou Wu
- Hubei Engineering Research Center for Biomaterials and Medical Protective Materials, Ministry of Education Key Laboratory of Material Chemistry for Energy Conversion and Storage, Hubei Key Laboratory of Bioinorganic Chemistry & Materia Medica, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology (HUST), 1037 Luoyu Road, Wuhan, 430074, China
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Sindhu S, Leung YH, Arefanian H, Madiraju SRM, Al‐Mulla F, Ahmad R, Prentki M. Neutral sphingomyelinase-2 and cardiometabolic diseases. Obes Rev 2021; 22:e13248. [PMID: 33738905 PMCID: PMC8365731 DOI: 10.1111/obr.13248] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 02/18/2021] [Accepted: 02/26/2021] [Indexed: 12/13/2022]
Abstract
Sphingolipids, in particular ceramides, play vital role in pathophysiological processes linked to metabolic syndrome, with implications in the development of insulin resistance, pancreatic ß-cell dysfunction, type 2 diabetes, atherosclerosis, inflammation, nonalcoholic steatohepatitis, and cancer. Ceramides are produced by the hydrolysis of sphingomyelin, catalyzed by different sphingomyelinases, including neutral sphingomyelinase 2 (nSMase2), whose dysregulation appears to underlie many of the inflammation-related pathologies. In this review, we discuss the current knowledge on the biochemistry of nSMase2 and ceramide production and its regulation by inflammatory cytokines, with particular reference to cardiometabolic diseases. nSMase2 contribution to pathogenic processes appears to involve cyclical feed-forward interaction with proinflammatory cytokines, such as TNF-α and IL-1ß, which activate nSMase2 and the production of ceramides, that in turn triggers the synthesis and release of inflammatory cytokines. We elaborate these pathogenic interactions at the molecular level and discuss the potential therapeutic benefits of inhibiting nSMase2 against inflammation-driven cardiometabolic diseases.
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Affiliation(s)
- Sardar Sindhu
- Animal and Imaging core facilityDasman Diabetes InstituteDasmanKuwait
| | - Yat Hei Leung
- Departments of Nutrition, Biochemistry and Molecular MedicineUniversity of MontrealMontréalQuebecCanada
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM)Montreal Diabetes Research CenterMontréalQuebecCanada
| | - Hossein Arefanian
- Immunology and Microbiology DepartmentDasman Diabetes InstituteDasmanKuwait
| | - S. R. Murthy Madiraju
- Departments of Nutrition, Biochemistry and Molecular MedicineUniversity of MontrealMontréalQuebecCanada
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM)Montreal Diabetes Research CenterMontréalQuebecCanada
| | - Fahd Al‐Mulla
- Department of Genetics and BioinformaticsDasman Diabetes InstituteDasmanKuwait
| | - Rasheed Ahmad
- Immunology and Microbiology DepartmentDasman Diabetes InstituteDasmanKuwait
| | - Marc Prentki
- Departments of Nutrition, Biochemistry and Molecular MedicineUniversity of MontrealMontréalQuebecCanada
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM)Montreal Diabetes Research CenterMontréalQuebecCanada
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Silvera S, Wilkinson JA, LeBlanc PJ. Characterization of neutral sphingomyelinase activity and isoform expression in rodent skeletal muscle mitochondria. Mitochondrion 2021; 59:184-189. [PMID: 34089907 DOI: 10.1016/j.mito.2021.06.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 05/04/2021] [Accepted: 06/01/2021] [Indexed: 12/01/2022]
Abstract
Skeletal muscle is composed of fiber types that differ in mitochondrial content, antioxidant capacity, and susceptibility to apoptosis. Ceramides have been linked to oxidative stress-mediated apoptotic intracellular signalling and the enzyme neutral sphingomyelinase (nSMase) is, in part, responsible for generating these ceramides through the hydrolysis of sphingomyelin. Despite the role of ceramides in mediating apoptosis, there is a gap in the literature regarding nSMase in skeletal muscle mitochondria. This study aimed to characterize total nSMase activity and individual isoform expression in isolated subsarcolemmal (SS) mitochondria from soleus, diaphragm, plantaris, and extensor digitorum longus (EDL). Total nSMase activity did not differ between muscle types. nSMase2 content was detectable in all muscles and higher in EDL, soleus, and plantaris compared to diaphragm whereas nSMase3 was undetectable in all muscles. Finally, total nSMase activity positively correlated to nSMase2 protein content in soleus but not the other muscles. These findings suggest that nSMase associated with SS mitochondria may play a role in intracellular signalling processes involving ceramides in skeletal muscle and nSMase2 may be the key isoform, specifically in slow twitch muscle like soleus. Further studies are needed to fully elucidate the specific contribution of nSMase, along with the role of the various isoforms and mitochondrial subpopulation in generating mitochondrial ceramides in skeletal muscle, and its potential effects on mediating apoptosis.
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Affiliation(s)
- Sebastian Silvera
- Center for Bone and Muscle Health, Faculty of Applied Health Science, Brock University, Canada
| | - Jennifer A Wilkinson
- Center for Bone and Muscle Health, Faculty of Applied Health Science, Brock University, Canada
| | - Paul J LeBlanc
- Center for Bone and Muscle Health, Faculty of Applied Health Science, Brock University, Canada.
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Skácel J, Slusher BS, Tsukamoto T. Small Molecule Inhibitors Targeting Biosynthesis of Ceramide, the Central Hub of the Sphingolipid Network. J Med Chem 2021; 64:279-297. [PMID: 33395289 PMCID: PMC8023021 DOI: 10.1021/acs.jmedchem.0c01664] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Ceramides are composed of a sphingosine and a single fatty acid connected by an amide linkage. As one of the major classes of biologically active lipids, ceramides and their upstream and downstream metabolites have been implicated in several pathological conditions including cancer, neurodegeneration, diabetes, microbial pathogenesis, obesity, and inflammation. Consequently, tremendous efforts have been devoted to deciphering the dynamics of metabolic pathways involved in ceramide biosynthesis. Given that several distinct enzymes can produce ceramide, different enzyme targets have been pursued depending on the underlying disease mechanism. The main objective of this review is to provide a comprehensive overview of small molecule inhibitors reported to date for each of these ceramide-producing enzymes from a medicinal chemistry perspective.
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Affiliation(s)
- Jan Skácel
- Johns Hopkins Drug Discovery and Department of Neurology, Johns Hopkins University, Baltimore, Maryland 21205, United States
| | - Barbara S. Slusher
- Johns Hopkins Drug Discovery and Department of Neurology, Johns Hopkins University, Baltimore, Maryland 21205, United States
| | - Takashi Tsukamoto
- Johns Hopkins Drug Discovery and Department of Neurology, Johns Hopkins University, Baltimore, Maryland 21205, United States
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The nSMase2/Smpd3 gene modulates the severity of muscular dystrophy and the emotional stress response in mdx mice. BMC Med 2020; 18:343. [PMID: 33208172 PMCID: PMC7677854 DOI: 10.1186/s12916-020-01805-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 10/01/2020] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND Duchenne muscular dystrophy (DMD) is a progressive, degenerative muscular disorder and cognitive dysfunction caused by mutations in the dystrophin gene. It is characterized by excess inflammatory responses in the muscle and repeated degeneration and regeneration cycles. Neutral sphingomyelinase 2/sphingomyelin phosphodiesterase 3 (nSMase2/Smpd3) hydrolyzes sphingomyelin in lipid rafts. This protein thus modulates inflammatory responses, cell survival or apoptosis pathways, and the secretion of extracellular vesicles in a Ca2+-dependent manner. However, its roles in dystrophic pathology have not yet been clarified. METHODS To investigate the effects of the loss of nSMase2/Smpd3 on dystrophic muscles and its role in the abnormal behavior observed in DMD patients, we generated mdx mice lacking the nSMase2/Smpd3 gene (mdx:Smpd3 double knockout [DKO] mice). RESULTS Young mdx:Smpd3 DKO mice exhibited reduced muscular degeneration and decreased inflammation responses, but later on they showed exacerbated muscular necrosis. In addition, the abnormal stress response displayed by mdx mice was improved in the mdx:Smpd3 DKO mice, with the recovery of brain-derived neurotrophic factor (Bdnf) expression in the hippocampus. CONCLUSIONS nSMase2/Smpd3-modulated lipid raft integrity is a potential therapeutic target for DMD.
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Cornell RB. Membrane Lipids Assist Catalysis by CTP: Phosphocholine Cytidylyltransferase. J Mol Biol 2020; 432:5023-5042. [PMID: 32234309 DOI: 10.1016/j.jmb.2020.03.024] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 03/22/2020] [Accepted: 03/25/2020] [Indexed: 02/06/2023]
Abstract
While most of the articles in this issue review the workings of integral membrane enzymes, in this review, we describe the catalytic mechanism of an enzyme that contains a soluble catalytic domain but appears to catalyze its reaction on the membrane surface, anchored and assisted by a separate regulatory amphipathic helical domain and inter-domain linker. Membrane partitioning of CTP: phosphocholine cytidylyltransferase (CCT), a key regulatory enzyme of phosphatidylcholine metabolism, is regulated chiefly by changes in membrane phospholipid composition, and boosts the enzyme's catalytic efficiency >200-fold. Catalytic enhancement by membrane binding involves the displacement of an auto-inhibitory helix from the active site entrance-way and promotion of a new conformational ensemble for the inter-domain, allosteric linker that has an active role in the catalytic cycle. We describe the evidence for close contact between membrane lipid, a compact allosteric linker, and the CCT active site, and discuss potential ways that this interaction enhances catalysis.
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Affiliation(s)
- Rosemary B Cornell
- Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, BC, Canada V5A-1S6.
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Huang Q, Li M, Lai L, Liu Z. Allostery of multidomain proteins with disordered linkers. Curr Opin Struct Biol 2020; 62:175-182. [PMID: 32151887 DOI: 10.1016/j.sbi.2020.01.017] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Revised: 01/18/2020] [Accepted: 01/31/2020] [Indexed: 02/07/2023]
Abstract
Intrinsically disordered regions are often involved in allosteric regulation of multidomain proteins. They can act as disordered linkers to connect and interact with domains, resulting in rather complex allosteric mechanism and novel protein behavior. Therefore, it is necessary to analyze the diverse functions of disordered linkers in order to better understand allostery and relevant regulation process. Here we summarize recent advances in understanding the function of linkers and the advantages of adopting mutlidomain architecture with disorder linkers. It was shown that linkers between domains enhance the local domain concentration and make the allosteric regulation of weakly interacting partners possible, while linkers with only one tethered end cause an entropy effect to reduce binding affinity and prevent aggregation.
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Affiliation(s)
- Qiaojing Huang
- BNLMS, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Maodong Li
- School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen 518055, China; Institute of Systems Biology, Shenzhen Bay Laboratory, Shenzhen 518055, China
| | - Luhua Lai
- BNLMS, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China; Center for Quantitative Biology, Peking University, Beijing 100871, China; Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China.
| | - Zhirong Liu
- BNLMS, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China.
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Börtlein C, Schumacher F, Kleuser B, Dölken L, Avota E. Role of Neutral Sphingomyelinase-2 (NSM 2) in the Control of T Cell Plasma Membrane Lipid Composition and Cholesterol Homeostasis. Front Cell Dev Biol 2019; 7:226. [PMID: 31681760 PMCID: PMC6803391 DOI: 10.3389/fcell.2019.00226] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Accepted: 09/24/2019] [Indexed: 12/12/2022] Open
Abstract
The activity of neutral sphingomyelinase-2 (NSM2) to catalyze the conversion of sphingomyelin (SM) to ceramide and phosphocholine at the cytosolic leaflet of plasma membrane (PM) is important in T cell receptor (TCR) signaling. We recently identified PKCζ as a major NSM2 downstream effector which regulates microtubular polarization. It remained, however, unclear to what extent NSM2 activity affected overall composition of PM lipids and downstream effector lipids in antigen stimulated T cells. Here, we provide a detailed lipidomics analyses on PM fractions isolated from TCR stimulated wild type and NSM2 deficient (ΔNSM) Jurkat T cells. This revealed that in addition to that of sphingolipids, NSM2 depletion also affected concentrations of many other lipids. In particular, NSM2 ablation resulted in increase of lyso-phosphatidylcholine (LPC) and lyso-phosphatidylethanolamine (LPE) which both govern PM biophysical properties. Crucially, TCR dependent upregulation of the important T cell signaling lipid diacylglycerol (DAG), which is fundamental for activation of conventional and novel PKCs, was abolished in ΔNSM cells. Moreover, NSM2 activity was found to play an important role in PM cholesterol transport to the endoplasmic reticulum (ER) and production of cholesteryl esters (CE) there. Most importantly, CE accumulation was essential to sustain human T cell proliferation. Accordingly, inhibition of CE generating enzymes, the cholesterol acetyltransferases ACAT1/SOAT1 and ACAT2/SOAT2, impaired TCR driven expansion of both CD4+ and CD8+ T cells. In summary, our study reveals an important role of NSM2 in regulating T cell functions by its multiple effects on PM lipids and cholesterol homeostasis.
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Affiliation(s)
- Charlene Börtlein
- Institute for Virology and Immunobiology, University of Würzburg, Würzburg, Germany
| | - Fabian Schumacher
- Department of Toxicology, Institute of Nutritional Science, Faculty of Mathematics and Natural Science, University of Potsdam, Nuthetal, Germany.,Department of Molecular Biology, University of Duisburg-Essen, Essen, Germany
| | - Burkhard Kleuser
- Department of Toxicology, Institute of Nutritional Science, Faculty of Mathematics and Natural Science, University of Potsdam, Nuthetal, Germany
| | - Lars Dölken
- Institute for Virology and Immunobiology, University of Würzburg, Würzburg, Germany
| | - Elita Avota
- Institute for Virology and Immunobiology, University of Würzburg, Würzburg, Germany
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Knowles DG, Lee J, Taneva SG, Cornell RB. Remodeling of the interdomain allosteric linker upon membrane binding of CCTα pulls its active site close to the membrane surface. J Biol Chem 2019; 294:15531-15543. [PMID: 31488548 DOI: 10.1074/jbc.ra119.009850] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 08/18/2019] [Indexed: 01/10/2023] Open
Abstract
The rate-limiting step in the biosynthesis of the major membrane phospholipid, phosphatidylcholine, is catalyzed by CTP:phosphocholine cytidylyltransferase (CCT), which is regulated by reversible membrane binding of a long amphipathic helix (domain M). The M domain communicates with the catalytic domain via a conserved ∼20-residue linker, essential for lipid activation of CCT. Previous analysis of this region (denoted as the αEC/J) using MD simulations, cross-linking, mutagenesis, and solvent accessibility suggested that membrane binding of domain M promotes remodeling of the αEC/J into a more compact structure that is required for enzyme activation. Here, using tryptophan fluorescence quenching, we show that the allosteric linker lies superficially on the membrane surface. Analyses with truncated CCTs show that the αEC/J can interact with lipids independently of the M domain. We observed strong FRET between engineered tryptophans in the αEC/J and vesicles containing dansyl-phosphatidylethanolamine that depended on the native J sequence. These data are incompatible with the extended conformation of the αE helix observed in the previously determined crystal structure of inactive CCT but support a bent αE helix conformation stabilized by J segment interactions. Our results suggest that the membrane-adsorbed, folded allosteric linker may partially cover the active site cleft and pull it close to the membrane surface, where cytidyl transfer can occur efficiently in a relatively anhydrous environment.
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Affiliation(s)
- Daniel G Knowles
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Jaeyong Lee
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Svetla G Taneva
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Rosemary B Cornell
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada .,Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
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