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Munakata R, Yazaki K. How did plants evolve the prenylation of specialized phenolic metabolites by means of UbiA prenyltransferases? CURRENT OPINION IN PLANT BIOLOGY 2024; 81:102601. [PMID: 38991464 DOI: 10.1016/j.pbi.2024.102601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2024] [Revised: 06/13/2024] [Accepted: 06/21/2024] [Indexed: 07/13/2024]
Abstract
Prenylated phenolics occur in over 4000 species in the plant kingdom, most of which are known as specialized metabolites with high chemical diversity. Many of them have been identified as pharmacologically active compounds from various medicinal plants, in which prenyl residues play a key role in these activities. Prenyltransferases (PTs) responsible for their biosynthesis have been intensively studied in the last two decades. These enzymes are membrane-bound proteins belonging to the UbiA superfamily that occurs from bacteria to humans, and in particular those involved in plant specialized metabolism show strict specificities for both substrates and products. This article reviews the enzymatic features of plant UbiA PTs, including C- and O-prenylation, molecular evolution, and application of UbiA PTs in synthetic biology.
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Affiliation(s)
- Ryosuke Munakata
- Laboratory of Plant Gene Expression, Research Institute for Sustainable Humanosphere, Kyoto University, Uji 611-0011, Japan
| | - Kazufumi Yazaki
- Laboratory of Plant Gene Expression, Research Institute for Sustainable Humanosphere, Kyoto University, Uji 611-0011, Japan.
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2
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Chang Z, Liu B, He H, Li X, Shi H. High expression of RUNX1 in colorectal cancer subtype accelerates malignancy by inhibiting HMGCR. Pharmacol Res 2024; 206:107293. [PMID: 38971271 DOI: 10.1016/j.phrs.2024.107293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2024] [Revised: 06/09/2024] [Accepted: 07/03/2024] [Indexed: 07/08/2024]
Abstract
Colorectal cancer (CRC) presents a complex landscape, characterized by both inter-tumor and intra-tumor heterogeneity. RUNX1, a gene implicated in modulating tumor cell growth, survival, and differentiation, remains incompletely understood regarding its impact on CRC prognosis. In our investigation, we discerned a positive correlation between elevated RUNX1 expression and aggressive phenotypes across various CRC subtypes. Notably, knockdown of RUNX1 demonstrated efficacy in restraining CRC proliferation both in vitro and in vivo, primarily through inducing apoptosis and impeding cell proliferation. Mechanistically, we unveiled a direct regulatory link between RUNX1 and cholesterol synthesis, mediated by its control over HMGCR expression. Knockdown of RUNX1 in CRC cells triggered HMGCR transcriptional activation, culminating in elevated cholesterol levels that subsequently hindered cancer progression. Clinically, heightened RUNX1 expression emerged as a prognostic marker for adverse outcomes in CRC patients. Our findings underscore the pivotal involvement of RUNX1 in CRC advancement and its potential as a therapeutic target. The unique influence of RUNX1 on cholesterol synthesis and HMGCR transcriptional regulation uncovers a novel pathway contributing to CRC progression.
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Affiliation(s)
- Zhilin Chang
- Beijing Tiantan Hospital, Capital Medical University, Beijing, China.
| | - Bing Liu
- Laboratory of Experimental Hematology, Fifth Medical Center of Chinese PLA General Hospital, Beijing, China; State Key Laboratory of Proteomics, Academy of Military Medical Sciences, Academy of Military Sciences, Beijing, China
| | - Han He
- Key Laboratory for Regenerative Medicine of Ministry of Education, Institute of Hematology, School of Medicine, Jinan University, Guangzhou, China.
| | - Xiaoyan Li
- Beijing Tiantan Hospital, Capital Medical University, Beijing, China.
| | - Hui Shi
- Beijing Tiantan Hospital, Capital Medical University, Beijing, China.
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3
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Stuart D, Zakhrabekova S, Jørgensen ME, Dockter C, Hansson M. A pipeline for identification of causal mutations in barley identifies Xantha-j as the chlorophyll synthase gene. PLANT PHYSIOLOGY 2024; 195:2877-2890. [PMID: 38630859 PMCID: PMC11288739 DOI: 10.1093/plphys/kiae218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Revised: 03/14/2024] [Accepted: 03/21/2024] [Indexed: 04/19/2024]
Abstract
Thousands of barley (Hordeum vulgare L.) mutants have been isolated over the last century, and many are stored in gene banks across various countries. In the present work, we developed a pipeline to efficiently identify causal mutations in barley. The pipeline is also efficient for mutations located in centromeric regions. Through bulked segregant analyses using whole genome sequencing of pooled F2 seedlings, we mapped 2 mutations and identified a limited number of candidate genes. We applied the pipeline on F2 mapping populations made from xan-j.59 (unknown mutation) and xan-l.82 (previously known). The Xantha-j (xan-j) gene was identified as encoding chlorophyll synthase, which catalyzes the last step in the chlorophyll biosynthetic pathway: the addition of a phytol moiety to the propionate side chain of chlorophyllide. Key amino acid residues in the active site, including the binding sites of the isoprenoid and chlorophyllide substrates, were analyzed in an AlphaFold2-generated structural model of the barley chlorophyll synthase. Three allelic mutants, xan-j.19, xan-j.59, and xan-j.64, were characterized. While xan-j.19 is a 1 base pair deletion and xan-j.59 is a nonsense mutation, xan-j.64 causes an S212F substitution in chlorophyll synthase. Our analyses of xan-j.64 and treatment of growing barley with clomazone, an inhibitor of chloroplastic isoprenoid biosynthesis, suggest that binding of the isoprenoid substrate is a prerequisite for the stable maintenance of chlorophyll synthase in the plastid. We further suggest that chlorophyll synthase is a sensor for coordinating chlorophyll and isoprenoid biosynthesis.
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Affiliation(s)
- David Stuart
- Department of Biology, Lund University, Sölvegatan 35B, 22362 Lund, Sweden
| | | | | | - Christoph Dockter
- Carlsberg Research Laboratory, J. C. Jacobsens Gade 4, 1799 Copenhagen V, Denmark
| | - Mats Hansson
- Department of Biology, Lund University, Sölvegatan 35B, 22362 Lund, Sweden
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4
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Ozkan-Nikitaras T, Grzesik DJ, Romano LEL, Chapple JP, King PJ, Shoulders CC. N-SREBP2 Provides a Mechanism for Dynamic Control of Cellular Cholesterol Homeostasis. Cells 2024; 13:1255. [PMID: 39120286 PMCID: PMC11311687 DOI: 10.3390/cells13151255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2024] [Revised: 07/05/2024] [Accepted: 07/22/2024] [Indexed: 08/10/2024] Open
Abstract
Cholesterol is required to maintain the functional integrity of cellular membrane systems and signalling pathways, but its supply must be closely and dynamically regulated because excess cholesterol is toxic. Sterol regulatory element-binding protein 2 (SREBP2) and the ER-resident protein HMG-CoA reductase (HMGCR) are key regulators of cholesterol biosynthesis. Here, we assessed the mechanistic aspects of their regulation in hepatic cells. Unexpectedly, we found that the transcriptionally active fragment of SREBP2 (N-SREBP2) was produced constitutively. Moreover, in the absence of an exogenous cholesterol supply, nuclear N-SREBP2 became resistant to proteasome-mediated degradation. This resistance was paired with increased occupancy at the HMGCR promoter and HMGCR expression. Inhibiting nuclear N-SREBP2 degradation did not increase HMGCR RNA levels; this increase required cholesterol depletion. Our findings, combined with previous physiological and biophysical investigations, suggest a new model of SREBP2-mediated regulation of cholesterol biosynthesis in the organ that handles large and rapid fluctuations in the dietary supply of this key lipid. Specifically, in the nucleus, cholesterol and the ubiquitin-proteasome system provide a short-loop system that modulates the rate of cholesterol biosynthesis via regulation of nuclear N-SREBP2 turnover and HMGCR expression. Our findings have important implications for maintaining cellular cholesterol homeostasis and lowering blood cholesterol via the SREBP2-HMGCR axis.
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Affiliation(s)
- Tozen Ozkan-Nikitaras
- Centre for Endocrinology, William Harvey Research Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London EC1M 6BQ, UK; (T.O.-N.); (D.J.G.); (L.E.L.R.); (J.P.C.); (P.J.K.)
| | - Dominika J. Grzesik
- Centre for Endocrinology, William Harvey Research Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London EC1M 6BQ, UK; (T.O.-N.); (D.J.G.); (L.E.L.R.); (J.P.C.); (P.J.K.)
- Department of Chemistry and Molecular Biology, University of Gothenburg, 405 30 Göteborg, Sweden
- Wallenberg Centre for Molecular and Translational Medicine, University of Gothenburg, 405 30 Göteborg, Sweden
| | - Lisa E. L. Romano
- Centre for Endocrinology, William Harvey Research Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London EC1M 6BQ, UK; (T.O.-N.); (D.J.G.); (L.E.L.R.); (J.P.C.); (P.J.K.)
| | - J. P. Chapple
- Centre for Endocrinology, William Harvey Research Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London EC1M 6BQ, UK; (T.O.-N.); (D.J.G.); (L.E.L.R.); (J.P.C.); (P.J.K.)
| | - Peter J. King
- Centre for Endocrinology, William Harvey Research Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London EC1M 6BQ, UK; (T.O.-N.); (D.J.G.); (L.E.L.R.); (J.P.C.); (P.J.K.)
| | - Carol C. Shoulders
- Centre for Endocrinology, William Harvey Research Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London EC1M 6BQ, UK; (T.O.-N.); (D.J.G.); (L.E.L.R.); (J.P.C.); (P.J.K.)
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5
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Vargas-Pérez MDLÁ, Devos DP, López-Lluch G. An AlphaFold Structure Analysis of COQ2 as Key a Component of the Coenzyme Q Synthesis Complex. Antioxidants (Basel) 2024; 13:496. [PMID: 38671943 PMCID: PMC11047366 DOI: 10.3390/antiox13040496] [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: 03/12/2024] [Revised: 04/16/2024] [Accepted: 04/19/2024] [Indexed: 04/28/2024] Open
Abstract
Coenzyme Q (CoQ) is a lipidic compound that is widely distributed in nature, with crucial functions in metabolism, protection against oxidative damage and ferroptosis and other processes. CoQ biosynthesis is a conserved and complex pathway involving several proteins. COQ2 is a member of the UbiA family of transmembrane prenyltransferases that catalyzes the condensation of the head and tail precursors of CoQ, which is a key step in the process, because its product is the first intermediate that will be modified in the head by the next components of the synthesis process. Mutations in this protein have been linked to primary CoQ deficiency in humans, a rare disease predominantly affecting organs with a high energy demand. The reaction catalyzed by COQ2 and its mechanism are still unknown. Here, we aimed at clarifying the COQ2 reaction by exploring possible substrate binding sites using a strategy based on homology, comprising the identification of available ligand-bound homologs with solved structures in the Protein Data Bank (PDB) and their subsequent structural superposition in the AlphaFold predicted model for COQ2. The results highlight some residues located on the central cavity or the matrix loops that may be involved in substrate interaction, some of which are mutated in primary CoQ deficiency patients. Furthermore, we analyze the structural modifications introduced by the pathogenic mutations found in humans. These findings shed new light on the understanding of COQ2's function and, thus, CoQ's biosynthesis and the pathogenicity of primary CoQ deficiency.
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Affiliation(s)
- María de los Ángeles Vargas-Pérez
- Departamento de Fisiología, Anatomía y Biología Celular, Centro Andaluz de Biología del Desarrollo (CABD), CSIC-UPO-JA, Universidad Pablo de Olavide, Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, Carretera de Utrera km1, 41013 Seville, Spain;
| | - Damien Paul Devos
- Centro Andaluz de Biología del Desarrollo (CABD), CSIC-UPO-JA, Universidad Pablo de Olavide, Carretera de Utrera km1, 41013 Seville, Spain;
| | - Guillermo López-Lluch
- Departamento de Fisiología, Anatomía y Biología Celular, Centro Andaluz de Biología del Desarrollo (CABD), CSIC-UPO-JA, Universidad Pablo de Olavide, Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, Carretera de Utrera km1, 41013 Seville, Spain;
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6
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Hirashima S, Kiyooka Y, Kaetsu S, Nakagawa K. Vitamin K converting enzyme UBIAD1 plays an important role in osteogenesis and chondrogenesis in mice. Biochem Biophys Res Commun 2024; 702:149635. [PMID: 38335702 DOI: 10.1016/j.bbrc.2024.149635] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Revised: 01/10/2024] [Accepted: 02/05/2024] [Indexed: 02/12/2024]
Abstract
Dietary vitamin K1 (phylloquinone: PK) and menaquinone (MK-n) are converted to menadione (MD) in the small intestine and then translocated to various tissues where they are converted to vitamin K2 (menaquinone-4: MK-4) by UbiA prenyltransferase domain containing protein 1 (UBIAD1). MK-4 is effective in bone formation and is used to treat osteoporosis in Japan. UBIAD1 is expressed in bone and osteoblasts and shows conversion to MK-4, but the role of UBIAD1 in osteogenesis is unknown. In this study, we investigated the function of UBIAD1 in osteogenesis using a tamoxifen-dependent UBIAD1-deficient mouse model. When UBIAD1 deficiency was induced from the first week of life, the femur was significantly shortened, and bone mineral density (BMD) was reduced. In addition, the expression of bone and chondrocyte matrix proteins and chondrocyte differentiation factors was significantly decreased. In primary cultured chondrocytes, chondrocyte differentiation was significantly reduced by UBIAD1 deficiency. These results suggest that UBIAD1 is an important factor for the regulation of chondrocyte proliferation and differentiation during osteogenesis.
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Affiliation(s)
- Shunsuke Hirashima
- Laboratory of Hygienic Sciences, Faculty of Pharmaceutical Sciences, Kobe Gakuin University, 1-1-3, Minatojima, Chuo-ku, Kobe Hyogo, 650-8586, Japan
| | - Yukino Kiyooka
- Laboratory of Hygienic Sciences, Faculty of Pharmaceutical Sciences, Kobe Gakuin University, 1-1-3, Minatojima, Chuo-ku, Kobe Hyogo, 650-8586, Japan
| | - Shinichiro Kaetsu
- Laboratory of Hygienic Sciences, Faculty of Pharmaceutical Sciences, Kobe Gakuin University, 1-1-3, Minatojima, Chuo-ku, Kobe Hyogo, 650-8586, Japan
| | - Kimie Nakagawa
- Laboratory of Hygienic Sciences, Faculty of Pharmaceutical Sciences, Kobe Gakuin University, 1-1-3, Minatojima, Chuo-ku, Kobe Hyogo, 650-8586, Japan.
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7
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Gao S, Wu F, Gurcha SS, Batt SM, Besra GS, Rao Z, Zhang L. Structural analysis of phosphoribosyltransferase-mediated cell wall precursor synthesis in Mycobacterium tuberculosis. Nat Microbiol 2024; 9:976-987. [PMID: 38491273 PMCID: PMC10994848 DOI: 10.1038/s41564-024-01643-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Accepted: 02/07/2024] [Indexed: 03/18/2024]
Abstract
In Mycobacterium tuberculosis, Rv3806c is a membrane-bound phosphoribosyltransferase (PRTase) involved in cell wall precursor production. It catalyses pentosyl phosphate transfer from phosphoribosyl pyrophosphate to decaprenyl phosphate, to generate 5-phospho-β-ribosyl-1-phosphoryldecaprenol. Despite Rv3806c being an attractive drug target, structural and molecular mechanistic insight into this PRTase is lacking. Here we report cryogenic electron microscopy structures for Rv3806c in the donor- and acceptor-bound states. In a lipidic environment, Rv3806c is trimeric, creating a UbiA-like fold. Each protomer forms two helical bundles, which, alongside the bound lipids, are required for PRTase activity in vitro. Mutational and functional analyses reveal that decaprenyl phosphate and phosphoribosyl pyrophosphate bind the intramembrane and extramembrane cavities of Rv3806c, respectively, in a distinct manner to that of UbiA superfamily enzymes. Our data suggest a model for Rv3806c-catalysed phosphoribose transfer through an inverting mechanism. These findings provide a structural basis for cell wall precursor biosynthesis that could have potential for anti-tuberculosis drug development.
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Affiliation(s)
- Shan Gao
- State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, College of Pharmacy, Nankai University, Tianjin, China
- Shanghai Institute for Advanced Immunochemical Studies, School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Fangyu Wu
- State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, College of Pharmacy, Nankai University, Tianjin, China
- Shanghai Institute for Advanced Immunochemical Studies, School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Sudagar S Gurcha
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham, UK
| | - Sarah M Batt
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham, UK
| | - Gurdyal S Besra
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham, UK.
| | - Zihe Rao
- State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, College of Pharmacy, Nankai University, Tianjin, China.
- Shanghai Institute for Advanced Immunochemical Studies, School of Life Science and Technology, ShanghaiTech University, Shanghai, China.
- Laboratory of Structural Biology, Tsinghua University, Beijing, China.
| | - Lu Zhang
- Shanghai Institute for Advanced Immunochemical Studies, School of Life Science and Technology, ShanghaiTech University, Shanghai, China.
- Shanghai Clinical Research and Trial Center, Shanghai, China.
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8
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Hou C, Huang M, Wang P, Zhang Q, Wang G, Gao S. Chronic exposure to 3,6-dichlorocarbazole exacerbates non-alcoholic fatty liver disease in zebrafish by disrupting lipid metabolism and inducing special lipid biomarker accumulation. CHEMOSPHERE 2024; 352:141442. [PMID: 38346516 DOI: 10.1016/j.chemosphere.2024.141442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Revised: 02/07/2024] [Accepted: 02/09/2024] [Indexed: 02/19/2024]
Abstract
Most previous studies have focused primarily on the adverse effects of environmental chemicals on organisms of good healthy. Although global prevalence of non-alcoholic fatty liver disease (NAFLD) has reached approximately 25%, the impact of environmentally persistent organic chemicals on organisms with NAFLD is substantially unknown. Polyhalogenated carbazoles (PHCZs) as emerging contaminants have been frequently detected in the environment and organisms. In this study, we investigated the impact of the most frequently detected PHCZs, 3,6-dichlorocarbazole (36-CCZ), on zebrafish with high-fat diet (HFD)-induced NAFLD. After 4 weeks exposure to environmentally relevant concentrations of 36-CCZ (0.16-0.45 μg/L), the accumulation of lipid in zebrafish liver dramatically increased, and the transcription of genes involved in lipid synthesis, transport and oxidation was significantly upregulated, demonstrating that 36-CCZ had exacerbated the NAFLD in zebrafish. Lipidomic analysis indicated that 36-CCZ had significantly affected liver lipid metabolic pathways, mainly including glycerolipids and glycerophospholipids. Additionally, fifteen lipids were identified as potential lipid biomarkers for 36-CCZ exacerbation of NAFLD, including diacylglycerols (DGs), triglycerides (TGs), phosphatidylcholines (PCs), phosphatidylethanolamines (PEs), phosphatidic acid (PA), and phosphatidylinositol (PI). These findings demonstrate that long-term exposure to 36-CCZ can promote the progression of NAFLD, which will contribute to raising awareness of the health risks of PHCZs.
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Affiliation(s)
- Cunchuang Hou
- School of Environmental Ecology and Biological Engineering, Key Laboratory for Green Chemical Process of Ministry of Education, Wuhan Institute of Technology, Wuhan, 430205, China
| | - Mengyao Huang
- School of Environmental Ecology and Biological Engineering, Key Laboratory for Green Chemical Process of Ministry of Education, Wuhan Institute of Technology, Wuhan, 430205, China
| | - Pingping Wang
- Department of Human Microbiome & Implantology & Orthodontics, School and Hospital of Stomatology, Cheeloo College of Medicine, Shandong University & Shandong Key Laboratory of Oral Tissue Regeneration & Shandong Engineering Laboratory for Dental Materials and Oral Tissue Regeneration, Jinan, 250012, China
| | - Qiaoyun Zhang
- School of Environmental Ecology and Biological Engineering, Key Laboratory for Green Chemical Process of Ministry of Education, Wuhan Institute of Technology, Wuhan, 430205, China
| | - Guowei Wang
- School of Environmental Ecology and Biological Engineering, Key Laboratory for Green Chemical Process of Ministry of Education, Wuhan Institute of Technology, Wuhan, 430205, China.
| | - Shixiang Gao
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210093, China
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9
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Faulkner RA, Yang Y, Tsien J, Qin T, DeBose-Boyd RA. Direct binding to sterols accelerates endoplasmic reticulum-associated degradation of HMG CoA reductase. Proc Natl Acad Sci U S A 2024; 121:e2318822121. [PMID: 38319967 PMCID: PMC10873557 DOI: 10.1073/pnas.2318822121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Accepted: 01/09/2024] [Indexed: 02/08/2024] Open
Abstract
The maintenance of cholesterol homeostasis is crucial for normal function at both the cellular and organismal levels. Two integral membrane proteins, 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGCR) and Scap, are key targets of a complex feedback regulatory system that operates to ensure cholesterol homeostasis. HMGCR catalyzes the rate-limiting step in the transformation of the 2-carbon precursor acetate to 27-carbon cholesterol. Scap mediates proteolytic activation of sterol regulatory element-binding protein-2 (SREBP-2), a membrane-bound transcription factor that controls expression of genes involved in the synthesis and uptake of cholesterol. Sterol accumulation triggers binding of HMGCR to endoplasmic reticulum (ER)-localized Insig proteins, leading to the enzyme's ubiquitination and proteasome-mediated ER-associated degradation (ERAD). Sterols also induce binding of Insigs to Scap, which leads to sequestration of Scap and its bound SREBP-2 in the ER, thereby preventing proteolytic activation of SREBP-2 in the Golgi. The oxygenated cholesterol derivative 25-hydroxycholesterol (25HC) and the methylated cholesterol synthesis intermediate 24,25-dihydrolanosterol (DHL) differentially modulate HMGCR and Scap. While both sterols promote binding of HMGCR to Insigs for ubiquitination and subsequent ERAD, only 25HC inhibits the Scap-mediated proteolytic activation of SREBP-2. We showed previously that 1,1-bisphosphonate esters mimic DHL, accelerating ERAD of HMGCR while sparing SREBP-2 activation. Building on these results, our current studies reveal specific, Insig-independent photoaffinity labeling of HMGCR by photoactivatable derivatives of the 1,1-bisphosphonate ester SRP-3042 and 25HC. These findings disclose a direct sterol binding mechanism as the trigger that initiates the HMGCR ERAD pathway, providing valuable insights into the intricate mechanisms that govern cholesterol homeostasis.
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Affiliation(s)
- Rebecca A. Faulkner
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX75390-9046
| | - Yangyan Yang
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX75390-9046
| | - Jet Tsien
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX75390-9046
| | - Tian Qin
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX75390-9046
| | - Russell A. DeBose-Boyd
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX75390-9046
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10
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Botsch JJ, Junker R, Sorgenfrei M, Ogger PP, Stier L, von Gronau S, Murray PJ, Seeger MA, Schulman BA, Bräuning B. Doa10/MARCH6 architecture interconnects E3 ligase activity with lipid-binding transmembrane channel to regulate SQLE. Nat Commun 2024; 15:410. [PMID: 38195637 PMCID: PMC10776854 DOI: 10.1038/s41467-023-44670-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Accepted: 12/19/2023] [Indexed: 01/11/2024] Open
Abstract
Transmembrane E3 ligases play crucial roles in homeostasis. Much protein and organelle quality control, and metabolic regulation, are determined by ER-resident MARCH6 E3 ligases, including Doa10 in yeast. Here, we present Doa10/MARCH6 structural analysis by cryo-EM and AlphaFold predictions, and a structure-based mutagenesis campaign. The majority of Doa10/MARCH6 adopts a unique circular structure within the membrane. This channel is established by a lipid-binding scaffold, and gated by a flexible helical bundle. The ubiquitylation active site is positioned over the channel by connections between the cytosolic E3 ligase RING domain and the membrane-spanning scaffold and gate. Here, by assaying 95 MARCH6 variants for effects on stability of the well-characterized substrate SQLE, which regulates cholesterol levels, we reveal crucial roles of the gated channel and RING domain consistent with AlphaFold-models of substrate-engaged and ubiquitylation complexes. SQLE degradation further depends on connections between the channel and RING domain, and lipid binding sites, revealing how interconnected Doa10/MARCH6 elements could orchestrate metabolic signals, substrate binding, and E3 ligase activity.
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Affiliation(s)
- J Josephine Botsch
- Department of Molecular Machines and Signaling, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152, Martinsried, Germany
- Technical University of Munich, School of Natural Sciences, Munich, Germany
| | - Roswitha Junker
- Department of Molecular Machines and Signaling, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152, Martinsried, Germany
| | - Michèle Sorgenfrei
- Institute of Medical Microbiology, University of Zurich, Gloriastrasse 28/30, 8006, Zurich, Switzerland
| | - Patricia P Ogger
- Research Group of Immunoregulation, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152, Martinsried, Germany
| | - Luca Stier
- Department of Molecular Machines and Signaling, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152, Martinsried, Germany
- Technical University of Munich, School of Natural Sciences, Munich, Germany
| | - Susanne von Gronau
- Department of Molecular Machines and Signaling, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152, Martinsried, Germany
| | - Peter J Murray
- Research Group of Immunoregulation, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152, Martinsried, Germany
| | - Markus A Seeger
- Institute of Medical Microbiology, University of Zurich, Gloriastrasse 28/30, 8006, Zurich, Switzerland
| | - Brenda A Schulman
- Department of Molecular Machines and Signaling, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152, Martinsried, Germany.
| | - Bastian Bräuning
- Department of Molecular Machines and Signaling, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152, Martinsried, Germany.
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11
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Zhu Q, Li G, Ma L, Chen B, Zhang D, Gao J, Deng S, Chen Y. Virgin Camellia Seed Oil Improves Glycolipid Metabolism in the Kidney of High Fat-Fed Rats through AMPK-SREBP Pathway. Nutrients 2023; 15:4888. [PMID: 38068746 PMCID: PMC10708295 DOI: 10.3390/nu15234888] [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: 10/04/2023] [Revised: 11/17/2023] [Accepted: 11/21/2023] [Indexed: 12/18/2023] Open
Abstract
Camellia seed oil (CO) is used as edible oil in southern China because of its excellent fatty acid composition and abundant bioactive compounds. Chronic kidney disease (CKD) is one of the most common chronic degenerative diseases in China, and active compounds in vegetable oil, like virgin olive oil, have been demonstrated to be efficacious in the management of CKD. In this study, virgin CO was refined using a standard process. The refining had minimal impact on the fatty acid composition, but significantly reduced the presence of bioactive compounds like polyphenols in CO. Sprague-Dawley (SD) rats fed with high fat diet (Group G) were treated with either virgin (Group Z) or refined CO (Group R). The oral administration of CO alleviated lipid accumulation and decreased body and kidney weight gain. Furthermore, treatment with virgin CO increased the renal ATP content. The renal expression levels of AMPK and key enzymes involved in fatty acid oxidation (CPT-1 and ACOX1) and glycolysis (HK, PFK, PK and GAPDH) were up-regulated in Group Z, thereby enhancing the ATP production. Virgin CO treatment downregulated the expression level of SREBP2 and its downstream target genes, such as ACC, FAS, and HMGCR, which reduced lipid synthesis. These findings indicate that virgin CO improves glycolipid metabolism and restores energy homeostasis in the kidneys of rats fed with a high-fat diet by modulating the AMPK-SREBP-signaling pathway, suggesting the potential of active compounds in virgin CO for managing the renal failure associated with glycolipid dysmetabolism.
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Affiliation(s)
- Qinhe Zhu
- National Engineering Research Center of Oiltea Camellia, State Key Laboratory of Utilization of Woody Oil Resource, Hunan Academy of Forestry, Shao Shan South Road, No. 658, Changsha 410004, China; (Q.Z.); (G.L.); (L.M.); (D.Z.)
- Hunan Key Laboratory of Economic Crops Genetic Improvement and Integrated Utilization, School of Life and Health Sciences, Hunan University of Science and Technology, Xiangtan 411201, China
| | - Guihui Li
- National Engineering Research Center of Oiltea Camellia, State Key Laboratory of Utilization of Woody Oil Resource, Hunan Academy of Forestry, Shao Shan South Road, No. 658, Changsha 410004, China; (Q.Z.); (G.L.); (L.M.); (D.Z.)
- Hunan Key Laboratory of Economic Crops Genetic Improvement and Integrated Utilization, School of Life and Health Sciences, Hunan University of Science and Technology, Xiangtan 411201, China
| | - Li Ma
- National Engineering Research Center of Oiltea Camellia, State Key Laboratory of Utilization of Woody Oil Resource, Hunan Academy of Forestry, Shao Shan South Road, No. 658, Changsha 410004, China; (Q.Z.); (G.L.); (L.M.); (D.Z.)
| | - Bolin Chen
- Co-Innovation Center for the Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing 210037, China
| | - Dawei Zhang
- National Engineering Research Center of Oiltea Camellia, State Key Laboratory of Utilization of Woody Oil Resource, Hunan Academy of Forestry, Shao Shan South Road, No. 658, Changsha 410004, China; (Q.Z.); (G.L.); (L.M.); (D.Z.)
- Hunan Key Laboratory of Economic Crops Genetic Improvement and Integrated Utilization, School of Life and Health Sciences, Hunan University of Science and Technology, Xiangtan 411201, China
| | - Jing Gao
- National Engineering Research Center of Oiltea Camellia, State Key Laboratory of Utilization of Woody Oil Resource, Hunan Academy of Forestry, Shao Shan South Road, No. 658, Changsha 410004, China; (Q.Z.); (G.L.); (L.M.); (D.Z.)
| | - Senwen Deng
- National Engineering Research Center of Oiltea Camellia, State Key Laboratory of Utilization of Woody Oil Resource, Hunan Academy of Forestry, Shao Shan South Road, No. 658, Changsha 410004, China; (Q.Z.); (G.L.); (L.M.); (D.Z.)
- Hunan Key Laboratory of Economic Crops Genetic Improvement and Integrated Utilization, School of Life and Health Sciences, Hunan University of Science and Technology, Xiangtan 411201, China
| | - Yongzhong Chen
- National Engineering Research Center of Oiltea Camellia, State Key Laboratory of Utilization of Woody Oil Resource, Hunan Academy of Forestry, Shao Shan South Road, No. 658, Changsha 410004, China; (Q.Z.); (G.L.); (L.M.); (D.Z.)
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12
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Li W, Pang Y, Jin K, Wang Y, Wu Y, Luo J, Xu W, Zhang X, Xu R, Wang T, Jiao L. Membrane contact sites orchestrate cholesterol homeostasis that is central to vascular aging. WIREs Mech Dis 2023; 15:e1612. [PMID: 37156598 DOI: 10.1002/wsbm.1612] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2022] [Revised: 02/12/2023] [Accepted: 04/19/2023] [Indexed: 05/10/2023]
Abstract
Chronological age causes structural and functional vascular deterioration and is a well-established risk factor for the development of cardiovascular diseases, leading to more than 40% of all deaths in the elderly. The etiology of vascular aging is complex; a significant impact arises from impaired cholesterol homeostasis. Cholesterol level is balanced through synthesis, uptake, transport, and esterification, the processes executed by multiple organelles. Moreover, organelles responsible for cholesterol homeostasis are spatially and functionally coordinated instead of isolated by forming the membrane contact sites. Membrane contact, mediated by specific protein-protein interaction, pulls opposing organelles together and creates the hybrid place for cholesterol transfer and further signaling. The membrane contact-dependent cholesterol transfer, together with the vesicular transport, maintains cholesterol homeostasis and has intimate implications in a growing list of diseases, including vascular aging-related diseases. Here, we summarized the latest advances regarding cholesterol homeostasis by highlighting the membrane contact-based regulatory mechanism. We also describe the downstream signaling under cholesterol homeostasis perturbations, prominently in cholesterol-rich conditions, stimulating age-dependent organelle dysfunction and vascular aging. Finally, we discuss potential cholesterol-targeting strategies for therapists regarding vascular aging-related diseases. This article is categorized under: Cardiovascular Diseases > Molecular and Cellular Physiology.
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Affiliation(s)
- Wenjing Li
- Laboratory of Computational Biology and Machine Intelligence, National Laboratory of Pattern Recognition, Institute of Automation, Chinese Academy of Sciences, Beijing, China
- School of Artificial Intelligence, University of Chinese Academy of Sciences, Beijing, China
| | - Yiyun Pang
- Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
| | - Kehan Jin
- Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
| | - Yuru Wang
- Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
| | - Yujie Wu
- Laboratory of Computational Biology and Machine Intelligence, National Laboratory of Pattern Recognition, Institute of Automation, Chinese Academy of Sciences, Beijing, China
| | - Jichang Luo
- Department of Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China
- China International Neuroscience Institute (China-INI), Beijing, China
| | - Wenlong Xu
- Department of Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China
- China International Neuroscience Institute (China-INI), Beijing, China
| | - Xiao Zhang
- Department of Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China
- China International Neuroscience Institute (China-INI), Beijing, China
| | - Ran Xu
- Department of Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China
- China International Neuroscience Institute (China-INI), Beijing, China
| | - Tao Wang
- Department of Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China
- China International Neuroscience Institute (China-INI), Beijing, China
| | - Liqun Jiao
- Department of Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China
- China International Neuroscience Institute (China-INI), Beijing, China
- Department of Interventional Radiology, Xuanwu Hospital, Capital Medical University, Beijing, China
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Peng XR, Unsicker SB, Gershenzon J, Qiu MH. Structural diversity, hypothetical biosynthesis, chemical synthesis, and biological activity of Ganoderma meroterpenoids. Nat Prod Rep 2023; 40:1354-1392. [PMID: 37051770 DOI: 10.1039/d3np00006k] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/14/2023]
Abstract
Covering: 2018 to 2022Meroterpenoids found in fungal species of the genus Ganoderma and known as Ganoderma meroterpenoids (GMs) are substances composed of a 1,2,4-trisubstituted benzene and a polyunsaturated side chain. These substances have attracted the attention of chemists and pharmacologists due to their diverse structures and significant bioactivity. In this review, we present the structures and possible biosynthesis of representative GMs newly found from 2018 to 2022, as well as chemical synthesis and biological activity of some interesting GMs. We propose for the first time a plausible biosynthetic pathway for GMs, which will certainly motivate further research on the biosynthetic pathway in Ganoderma species, as well as on chemical synthesis of GMs as important bioactive compounds for the purpose of drug development.
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Affiliation(s)
- Xing-Rong Peng
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Science, Kunming 650201, China.
- Kunming College of Life Science, University of Chinese Academy of Sciences, Kunming 650204, China
| | - Sybille B Unsicker
- Max Planck Institute for Chemical Ecology, Department of Biochemistry, Hans-Knöll Str. 8, 07745 Jena, Germany
| | - Jonathan Gershenzon
- Max Planck Institute for Chemical Ecology, Department of Biochemistry, Hans-Knöll Str. 8, 07745 Jena, Germany
| | - Ming-Hua Qiu
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Science, Kunming 650201, China.
- Kunming College of Life Science, University of Chinese Academy of Sciences, Kunming 650204, China
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14
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Dominicis A, Del Giovane A, Torreggiani M, Recchia AD, Ciccarone F, Ciriolo MR, Ragnini-Wilson A. N-Acetylaspartate Drives Oligodendroglial Differentiation via Histone Deacetylase Activation. Cells 2023; 12:1861. [PMID: 37508525 PMCID: PMC10378218 DOI: 10.3390/cells12141861] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Revised: 07/09/2023] [Accepted: 07/12/2023] [Indexed: 07/30/2023] Open
Abstract
An unmet clinical goal in demyelinating pathologies is to restore the myelin sheath prior to neural degeneration. N-acetylaspartate (NAA) is an acetylated derivative form of aspartate, abundant in the healthy brain but severely reduced during traumatic brain injury and in patients with neurodegenerative pathologies. How extracellular NAA variations impact the remyelination process and, thereby, the ability of oligodendrocytes to remyelinate axons remains unexplored. Here, we evaluated the remyelination properties of the oligodendroglial (OL) mouse cell line Oli-neuM under different concentrations of NAA using a combination of biochemical, qPCR, immunofluorescence assays, and in vitro engagement tests, at NAA doses compatible with those observed in healthy brains and during brain injury. We observed that oligodendroglia cells respond to decreasing levels of NAA by stimulating differentiation and promoting gene expression of myelin proteins in a temporally regulated manner. Low doses of NAA potently stimulate Oli-neuM to engage with synthetic axons. Furthermore, we show a concentration-dependent expression of specific histone deacetylases essential for MBP gene expression under NAA or Clobetasol treatment. These data are consistent with the idea that oligodendrocytes respond to lowering the NAA concentration by activating the remyelination process via deacetylase activation.
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Affiliation(s)
| | - Alice Del Giovane
- Department of Biology, University of Rome Tor Vergata, 00133 Rome, Italy
| | - Matteo Torreggiani
- Department of Biology, University of Rome Tor Vergata, 00133 Rome, Italy
| | | | - Fabio Ciccarone
- Department of Biology, University of Rome Tor Vergata, 00133 Rome, Italy
- IRCCS San Raffaele, 00166 Rome, Italy
| | - Maria Rosa Ciriolo
- Department of Biology, University of Rome Tor Vergata, 00133 Rome, Italy
- IRCCS San Raffaele, 00166 Rome, Italy
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15
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Zheng YK, Zhou ZS, Wang GZ, Tu JY, Cheng HB, Ma SZ, Ke C, Wang Y, Jian QP, Shu YH, Wu XW. MiR-122-5p regulates the mevalonate pathway by targeting p53 in non-small cell lung cancer. Cell Death Dis 2023; 14:234. [PMID: 37005437 PMCID: PMC10067850 DOI: 10.1038/s41419-023-05761-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2022] [Revised: 03/02/2023] [Accepted: 03/21/2023] [Indexed: 04/04/2023]
Abstract
The 5-year survival rate of non-small cell lung cancer (NSCLC) patients is very low. MicroRNAs (miRNAs) are involved in the occurrence of NSCLC. miR-122-5p interacts with wild-type p53 (wtp53), and wtp53 affects tumor growth by inhibiting the mevalonate (MVA) pathway. Therefore, this study aimed to evaluate the role of these factors in NSCLC. The role of miR-122-5p and p53 was established in samples from NSCLC patients, and human NSCLC cells A549 using the miR-122-5p inhibitor, miR-122-5p mimic, and si-p53. Our results showed that inhibiting miR-122-5p expression led to the activation of p53. This inhibited the progression of the MVA pathway in the NSCLC cells A549, hindered cell proliferation and migration, and promoted apoptosis. miR-122-5p was negatively correlated with p53 expression in p53 wild-type NSCLC patients. The expression of key genes in the MVA pathway in tumors of p53 wild-type NSCLC patients was not always higher than the corresponding normal tissues. The malignancy of NSCLC was positively correlated with the high expression of the key genes in the MVA pathway. Therefore, miR-122-5p regulated NSCLC by targeting p53, providing potential molecular targets for developing targeted drugs.
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Affiliation(s)
- Yu-Kun Zheng
- Department of Thoracic Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
- College of Pharmacy, Hubei University of Chinese Medicine, Wuhan, 430065, China
| | - Zhong-Shi Zhou
- College of Pharmacy, Hubei University of Chinese Medicine, Wuhan, 430065, China
- Hubei Engineering Technology Research Center of Chinese Material Medical Processing Technology, Wuhan, 430065, China
| | - Guang-Zhong Wang
- College of Pharmacy, Hubei University of Chinese Medicine, Wuhan, 430065, China
- Hubei Engineering Technology Research Center of Chinese Material Medical Processing Technology, Wuhan, 430065, China
| | - Ji-Yuan Tu
- College of Pharmacy, Hubei University of Chinese Medicine, Wuhan, 430065, China
- Hubei Engineering Technology Research Center of Chinese Material Medical Processing Technology, Wuhan, 430065, China
| | - Huan-Bo Cheng
- College of Pharmacy, Hubei University of Chinese Medicine, Wuhan, 430065, China
| | - Shang-Zhi Ma
- College of Pharmacy, Hubei University of Chinese Medicine, Wuhan, 430065, China
| | - Chang Ke
- College of Pharmacy, Hubei University of Chinese Medicine, Wuhan, 430065, China
| | - Yan Wang
- College of Pharmacy, Hubei University of Chinese Medicine, Wuhan, 430065, China
| | - Qi-Pan Jian
- College of Pharmacy, Hubei University of Chinese Medicine, Wuhan, 430065, China
| | - Yu-Hang Shu
- College of Pharmacy, Hubei University of Chinese Medicine, Wuhan, 430065, China
| | - Xiao-Wei Wu
- Department of Thoracic Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China.
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16
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The Nox2-ROS-Nlrp3 Inflammasome Signaling Stimulates in the Hematopoietic Stem/Progenitor Cells Lipogenesis to Facilitate Membrane Lipid Raft Formation. Stem Cell Rev Rep 2023; 19:92-103. [PMID: 36441489 PMCID: PMC9823029 DOI: 10.1007/s12015-022-10481-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/10/2022] [Indexed: 11/29/2022]
Abstract
Proliferation, metabolism, and migration of hematopoietic stem/progenitor cells (HSPCs) are coordinated by receptors expressed on outer cell membranes that are integrated into microdomains, known as membrane lipid rafts (MLRs). These structures float freely in the cell membrane bilayer and are enriched in cholesterol and sphingolipids for their functional integrity. Receptors, if expressed in MLRs, have prolonged occupancy on the cell surface and enhanced signaling power. Based on this, we have become interested in the regulation of synthesis of MLRs components in HSPCs. To address this, we tested the effect of selected factors that promote proliferation or migration and their potential involvement in the synthesis of MLRs components in HSPCs. Based on our previous research showing that HSPCs from Nox2-KO and Nlrp3-KO mice display a profound defect in MLRs formation, we focused on the role of Nox2-ROS-Nlrp3 inflammasome in regulating lipogenesis in HSPCs. We found that while at steady state conditions, Nox2-derived ROS is required for a proper expression of enzymes regulating lipogenesis, during inflammation, this effect is augmented by Nlrp3 inflammasome. Thus, our data sheds new light on the regulation of lipogenesis in HSPCs and the involvement of the Nox2-ROS-Nlrp3 inflammasome axis that differently regulates lipogenesis at steady state conditions and in response to inflammation, modulating MLRs-mediated responsiveness of these cells to external stimuli.
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17
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Faulkner R, Jo Y. Synthesis, function, and regulation of sterol and nonsterol isoprenoids. Front Mol Biosci 2022; 9:1006822. [PMID: 36275615 PMCID: PMC9579336 DOI: 10.3389/fmolb.2022.1006822] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Accepted: 09/06/2022] [Indexed: 11/30/2022] Open
Abstract
Cholesterol, the bulk end-product of the mevalonate pathway, is a key component of cellular membranes and lipoproteins that transport lipids throughout the body. It is also a precursor of steroid hormones, vitamin D, and bile acids. In addition to cholesterol, the mevalonate pathway yields a variety of nonsterol isoprenoids that are essential to cell survival. Flux through the mevalonate pathway is tightly controlled to ensure cells continuously synthesize nonsterol isoprenoids but avoid overproducing cholesterol and other sterols. Endoplasmic reticulum (ER)-localized 3-hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase (HMGCR), the rate limiting enzyme in the mevalonate pathway, is the focus of a complex feedback regulatory system governed by sterol and nonsterol isoprenoids. This review highlights transcriptional and post-translational regulation of HMGCR. Transcriptional regulation of HMGCR is mediated by the Scap-SREBP pathway. Post-translational control is initiated by the intracellular accumulation of sterols, which causes HMGCR to become ubiquitinated and subjected to proteasome-mediated ER-associated degradation (ERAD). Sterols also cause a subfraction of HMGCR molecules to bind the vitamin K2 synthetic enzyme, UbiA prenyltransferase domain-containing protein-1 (UBIAD1). This binding inhibits ERAD of HMGCR, which allows cells to continuously synthesize nonsterol isoprenoids such as geranylgeranyl pyrophosphate (GGPP), even when sterols are abundant. Recent studies reveal that UBIAD1 is a GGPP sensor, dissociating from HMGCR when GGPP thresholds are met to allow maximal ERAD. Animal studies using genetically manipulated mice disclose the physiological significance of the HMGCR regulatory system and we describe how dysregulation of these pathways contributes to disease.
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