1
|
Coates HW, Nguyen TB, Du X, Olzomer EM, Farrell R, Byrne FL, Yang H, Brown AJ. The constitutively active form of a key cholesterol synthesis enzyme is lipid droplet-localized and upregulated in endometrial cancer tissues. J Biol Chem 2024; 300:107232. [PMID: 38537696 PMCID: PMC11061744 DOI: 10.1016/j.jbc.2024.107232] [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: 02/29/2024] [Accepted: 03/18/2024] [Indexed: 04/26/2024] Open
Abstract
Cholesterol is essential for both normal cell viability and cancer cell proliferation. Aberrant activity of squalene monooxygenase (SM, also known as squalene epoxidase), the rate-limiting enzyme of the committed cholesterol synthesis pathway, is accordingly implicated in a growing list of cancers. We previously reported that hypoxia triggers the truncation of SM to a constitutively active form, thus preserving sterol synthesis during oxygen shortfalls. Here, we show SM truncation is upregulated and correlates with the magnitude of hypoxia in endometrial cancer tissues, supporting the in vivo relevance of our earlier work. To further investigate the pathophysiological consequences of SM truncation, we examined its lipid droplet-localized pool using complementary immunofluorescence and cell fractionation approaches and found that it exclusively comprises the truncated enzyme. This partitioning is facilitated by the loss of an endoplasmic reticulum-embedded region at the SM N terminus, whereas the catalytic domain containing membrane-associated C-terminal helices is spared. Moreover, we determined multiple amphipathic helices contribute to the lipid droplet localization of truncated SM. Taken together, our results expand on the striking differences between the two forms of SM and suggest upregulated truncation may contribute to SM-related oncogenesis.
Collapse
Affiliation(s)
- Hudson W Coates
- School of Biotechnology and Biomolecular Sciences, UNSW, Sydney, New South Wales, Australia
| | - Tina B Nguyen
- School of Biotechnology and Biomolecular Sciences, UNSW, Sydney, New South Wales, Australia
| | - Ximing Du
- School of Biotechnology and Biomolecular Sciences, UNSW, Sydney, New South Wales, Australia
| | - Ellen M Olzomer
- School of Biotechnology and Biomolecular Sciences, UNSW, Sydney, New South Wales, Australia
| | - Rhonda Farrell
- Chris O'Brien Lifehouse, Camperdown, New South Wales, Australia; Prince of Wales Private Hospital, Randwick, New South Wales, Australia
| | - Frances L Byrne
- School of Biotechnology and Biomolecular Sciences, UNSW, Sydney, New South Wales, Australia
| | - Hongyuan Yang
- School of Biotechnology and Biomolecular Sciences, UNSW, Sydney, New South Wales, Australia
| | - Andrew J Brown
- School of Biotechnology and Biomolecular Sciences, UNSW, Sydney, New South Wales, Australia.
| |
Collapse
|
2
|
Zou Y, Zhang Y, Li M, Cao K, Song C, Zhang Z, Cai K, Geng D, Chen S, Wu Y, Zhang N, Sun G, Wang J, Zhang Y, Sun Y. Regulation of lipid metabolism by E3 ubiquitin ligases in lipid-associated metabolic diseases. Int J Biol Macromol 2024; 265:130961. [PMID: 38508558 DOI: 10.1016/j.ijbiomac.2024.130961] [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: 07/25/2023] [Revised: 03/10/2024] [Accepted: 03/15/2024] [Indexed: 03/22/2024]
Abstract
Previous studies have progressively elucidated the involvement of E3 ubiquitin (Ub) ligases in regulating lipid metabolism. Ubiquitination, facilitated by E3 Ub ligases, modifies critical enzymes in lipid metabolism, enabling them to respond to specific signals. In this review, we aim to present a comprehensive analysis of the role of E3 Ub ligases in lipid metabolism, which includes lipid synthesis and lipolysis, and their influence on cellular lipid homeostasis through the modulation of lipid uptake and efflux. Furthermore, it explores how the ubiquitination process governs the degradation or activation of pivotal enzymes, thereby regulating lipid metabolism at the transcriptional level. Perturbations in lipid metabolism have been implicated in various diseases, including hepatic lipid metabolism disorders, atherosclerosis, diabetes, and cancer. Therefore, this review focuses on the association between E3 Ub ligases and lipid metabolism in lipid-related diseases, highlighting enzymes critically involved in lipid synthesis and catabolism, transcriptional regulators, lipid uptake translocators, and transporters. Overall, this review aims to identify gaps in current knowledge, highlight areas requiring further research, offer potential targeted therapeutic approaches, and provide a comprehensive outlook on clinical conditions associated with lipid metabolic diseases.
Collapse
Affiliation(s)
- Yuanming Zou
- Department of Cardiology, the First Hospital of China Medical University, 155 Nanjing North Street, Heping District, Shenyang, 110001, Liaoning Province, People's Republic of China
| | - Ying Zhang
- Department of Cardiology, the First Hospital of China Medical University, 155 Nanjing North Street, Heping District, Shenyang, 110001, Liaoning Province, People's Republic of China; Institute of Health Sciences, China Medical University, 77 Puhe Road, Shenbei New District, Shenyang, 110001, Liaoning Province, People's Republic of China.
| | - Mohan Li
- Department of Cardiology, the First Hospital of China Medical University, 155 Nanjing North Street, Heping District, Shenyang, 110001, Liaoning Province, People's Republic of China
| | - Kexin Cao
- Department of Cardiology, the First Hospital of China Medical University, 155 Nanjing North Street, Heping District, Shenyang, 110001, Liaoning Province, People's Republic of China
| | - Chunyu Song
- Department of Cardiology, the First Hospital of China Medical University, 155 Nanjing North Street, Heping District, Shenyang, 110001, Liaoning Province, People's Republic of China
| | - Zhaobo Zhang
- Department of Cardiology, the First Hospital of China Medical University, 155 Nanjing North Street, Heping District, Shenyang, 110001, Liaoning Province, People's Republic of China
| | - Kexin Cai
- Department of Cardiology, the First Hospital of China Medical University, 155 Nanjing North Street, Heping District, Shenyang, 110001, Liaoning Province, People's Republic of China
| | - Danxi Geng
- Department of Cardiology, the First Hospital of China Medical University, 155 Nanjing North Street, Heping District, Shenyang, 110001, Liaoning Province, People's Republic of China
| | - Shuxian Chen
- Department of Cardiology, the First Hospital of China Medical University, 155 Nanjing North Street, Heping District, Shenyang, 110001, Liaoning Province, People's Republic of China
| | - Yanjiao Wu
- Department of Cardiology, the First Hospital of China Medical University, 155 Nanjing North Street, Heping District, Shenyang, 110001, Liaoning Province, People's Republic of China
| | - Naijin Zhang
- Department of Cardiology, the First Hospital of China Medical University, 155 Nanjing North Street, Heping District, Shenyang, 110001, Liaoning Province, People's Republic of China; Institute of Health Sciences, China Medical University, 77 Puhe Road, Shenbei New District, Shenyang, 110001, Liaoning Province, People's Republic of China; Key Laboratory of Reproductive and Genetic Medicine (China Medical University), National Health Commission, 77 Puhe Road, Shenbei New District, Shenyang, 110001, Liaoning Province, People's Republic of China
| | - Guozhe Sun
- Department of Cardiology, the First Hospital of China Medical University, 155 Nanjing North Street, Heping District, Shenyang, 110001, Liaoning Province, People's Republic of China.
| | - Jing Wang
- Department of Hematology, the First Hospital of China Medical University, 155 Nanjing North Street, Heping District, Shenyang, 110001, Liaoning Province, People's Republic of China.
| | - Yixiao Zhang
- Department of Urology Surgery, Shengjing Hospital of China Medical University, 36 Sanhao Street, Heping District, Shenyang, 110004, Liaoning Province, People's Republic of China.
| | - Yingxian Sun
- Department of Cardiology, the First Hospital of China Medical University, 155 Nanjing North Street, Heping District, Shenyang, 110001, Liaoning Province, People's Republic of China; Institute of Health Sciences, China Medical University, 77 Puhe Road, Shenbei New District, Shenyang, 110001, Liaoning Province, People's Republic of China; Key Laboratory of Environmental Stress and Chronic Disease Control and Prevention, Ministry of Education, China Medical University, 77 Puhe Road, Shenbei New District, Shenyang, 110001, Liaoning Province, People's Republic of China.
| |
Collapse
|
3
|
Zhang L, Cao Z, Hong Y, He H, Chen L, Yu Z, Gao Y. Squalene Epoxidase: Its Regulations and Links with Cancers. Int J Mol Sci 2024; 25:3874. [PMID: 38612682 PMCID: PMC11011400 DOI: 10.3390/ijms25073874] [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: 01/09/2024] [Revised: 03/09/2024] [Accepted: 03/19/2024] [Indexed: 04/14/2024] Open
Abstract
Squalene epoxidase (SQLE) is a key enzyme in the mevalonate-cholesterol pathway that plays a critical role in cellular physiological processes. It converts squalene to 2,3-epoxysqualene and catalyzes the first oxygenation step in the pathway. Recently, intensive efforts have been made to extend the current knowledge of SQLE in cancers through functional and mechanistic studies. However, the underlying mechanisms and the role of SQLE in cancers have not been fully elucidated yet. In this review, we retrospected current knowledge of SQLE as a rate-limiting enzyme in the mevalonate-cholesterol pathway, while shedding light on its potential as a diagnostic and prognostic marker, and revealed its therapeutic values in cancers. We showed that SQLE is regulated at different levels and is involved in the crosstalk with iron-dependent cell death. Particularly, we systemically reviewed the research findings on the role of SQLE in different cancers. Finally, we discussed the therapeutic implications of SQLE inhibitors and summarized their potential clinical values. Overall, this review discussed the multifaceted mechanisms that involve SQLE to present a vivid panorama of SQLE in cancers.
Collapse
Affiliation(s)
- Lin Zhang
- Department of Thoracic Surgery, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital & Shenzhen Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Shenzhen 518116, China
| | - Zheng Cao
- Department of Pathology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100021, China
| | - Yuheng Hong
- Department of Thoracic Surgery, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100021, China
| | - Haihua He
- Department of Thoracic Surgery, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100021, China
- Department of Oncology, Renmin Hospital of Wuhan University, Wuhan 430060, China
| | - Leifeng Chen
- Department of Thoracic Surgery, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100021, China
- Department of Oncology, Renmin Hospital of Wuhan University, Wuhan 430060, China
| | - Zhentao Yu
- Department of Thoracic Surgery, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital & Shenzhen Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Shenzhen 518116, China
| | - Yibo Gao
- Central Laboratory & Shenzhen Key Laboratory of Epigenetics and Precision Medicine for Cancers, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital & Shenzhen Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Shenzhen 518116, China
- State Key Laboratory of Molecular Oncology, National Cancer Center, National Clinical Research Center for Cancer, Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100021, China
- Laboratory of Translational Medicine, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100021, China
| |
Collapse
|
4
|
Sharma N, Koul M, Joshi NC, Dufossé L, Mishra A. Fungal-Bacterial Combinations in Plant Health under Stress: Physiological and Biochemical Characteristics of the Filamentous Fungus Serendipita indica and the Actinobacterium Zhihengliuella sp. ISTPL4 under In Vitro Arsenic Stress. Microorganisms 2024; 12:405. [PMID: 38399809 PMCID: PMC10892705 DOI: 10.3390/microorganisms12020405] [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: 01/12/2024] [Revised: 02/01/2024] [Accepted: 02/06/2024] [Indexed: 02/25/2024] Open
Abstract
Fungal-bacterial combinations have a significant role in increasing and improving plant health under various stress conditions. Metabolites secreted by fungi and bacteria play an important role in this process. Our study emphasizes the significance of secondary metabolites secreted by the fungus Serendipita indica alone and by an actinobacterium Zhihengliuella sp. ISTPL4 under normal growth conditions and arsenic (As) stress condition. Here, we evaluated the arsenic tolerance ability of S. indica alone and in combination with Z. sp. ISTPL4 under in vitro conditions. The growth of S. indica and Z. sp. ISTPL4 was measured in varying concentrations of arsenic and the effect of arsenic on spore size and morphology of S. indica was determined using confocal microscopy and scanning electron microscopy. The metabolomics study indicated that S. indica alone in normal growth conditions and under As stress released pentadecanoic acid, glycerol tricaprylate, L-proline and cyclo(L-prolyl-L-valine). Similarly, d-Ribose, 2-deoxy-bis(thioheptyl)-dithioacetal were secreted by a combination of S. indica and Z. sp. ISTPL4. Confocal studies revealed that spore size of S. indica decreased by 18% at 1.9 mM and by 15% when in combination with Z. sp. ISTPL4 at a 2.4 mM concentration of As. Arsenic above this concentration resulted in spore degeneration and hyphae fragmentation. Scanning electron microscopy (SEM) results indicated an increased spore size of S. indica in the presence of Z. sp. ISTPL4 (18 ± 0.75 µm) compared to S. indica alone (14 ± 0.24 µm) under normal growth conditions. Our study concluded that the suggested combination of microbial consortium can be used to increase sustainable agriculture by combating biotic as well as abiotic stress. This is because the metabolites released by the microbial combination display antifungal and antibacterial properties. The metabolites, besides evading stress, also confer other survival strategies. Therefore, the choice of consortia and combination partners is important and can help in developing strategies for coping with As stress.
Collapse
Affiliation(s)
- Neha Sharma
- Amity Institute of Microbial Technology, Amity University, Noida 201313, India; (N.S.); (N.C.J.)
| | - Monika Koul
- Department of Botany, Hansraj College, University of Delhi, Delhi 110007, India;
| | - Naveen Chandra Joshi
- Amity Institute of Microbial Technology, Amity University, Noida 201313, India; (N.S.); (N.C.J.)
| | - Laurent Dufossé
- Chemistry and Biotechnology of Natural Products, CHEMBIOPRO, Université de La Réunion, ESIROI Agroalimentaire, 15 Avenue René Cassin, CS 92003, CEDEX 9, F-97744 Saint-Denis, France
| | - Arti Mishra
- Department of Botany, Hansraj College, University of Delhi, Delhi 110007, India;
- Umeå Plant Science Center, Department of Plant Physiology, Umeå University, 90187 Umeå, Sweden
| |
Collapse
|
5
|
Liu XH, Pang X, Jin L, Pu DY, Wang ZJ, Zhang YG. Exposure to acute waterborne cadmium caused severe damage on lipid metabolism of freshwater fish, revealed by nuclear lipid droplet deposition in hepatocytes of rare minnow. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2023; 257:106433. [PMID: 36841070 DOI: 10.1016/j.aquatox.2023.106433] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2021] [Revised: 02/02/2023] [Accepted: 02/16/2023] [Indexed: 05/12/2023]
Abstract
Cadmium (Cd) is a widely distributed aquatic toxic heavy metal with the potential to disrupt fish metabolism; however, more research is needed to clarify the underlying mechanisms. In the present study, rare minnows (Gobiocypris rarus) were used to detect the effects of cadmium on freshwater fish lipid metabolism and its underlying mechanism by histopathological observation, measurement of serum and liver biochemical indexes, and analysis of gene expression in terms of lipid oxidation, synthesis and transport. Here, severe damage, such as cytoplasmic lipid droplet (LD) accumulation, ectopic deposition of LDs, and the appearance of nuclear LDs (nLDs), was detected after exposure to 2.0 mg/L or higher concentrations (2.5 and 2.8 mg/L CdCl2) for 96 h. Other damage included abnormal increases in rough endoplasmic reticulum (RER) lamellae in a fingerprint or concentric circle pattern and necrosis of hepatocytes, and which was observed in the livers of fish exposed to 2.0 mg/L CdCl2.. Both hepatic and serum lipids, such as triglycerides and total cholesterol, were significantly increased after exposure to 2.0 mg/L CdCl2, as was serum lipase (LPS). Hepatic lipase and lipoprotein lipase remained unchanged, in accordance with the unchanged hepatic mRNA transcripts of PPARɑ. Furthermore, the mRNA transcripts of both SCD and SQLE were significantly decreased. Moreover, hepatic and serum low-density and high-density lipoprotein cholesterol showed significant changes, which were accompanied by a significant increase and decrease in hepatic APOAI and APOB100 mRNA levels, respectively. All the results indicate the presence of severe damage to hepatic lipid metabolism and that disrupted lipid transport may play a key role in the accumulation of hepatic LDs. In addition, the hepatic nLDs of nonmammalian vertebrates and their location across the nuclear envelope are intriguing, suggesting that large-size nLDs are a common marker for severe liver damage.
Collapse
Affiliation(s)
- Xiao-Hong Liu
- Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Key Laboratory of Aquatic Science of Chongqing, Southwest University School of Life Sciences, Chongqing 400715, China
| | - Xu Pang
- College of Fisheries, Institute of Three Gorges Ecological Fisheries of Chongqing, Southwest University, Chongqing 400715, China
| | - Li Jin
- Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Key Laboratory of Aquatic Science of Chongqing, Southwest University School of Life Sciences, Chongqing 400715, China
| | - De-Yong Pu
- Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Key Laboratory of Aquatic Science of Chongqing, Southwest University School of Life Sciences, Chongqing 400715, China
| | - Zhi-Jian Wang
- Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Key Laboratory of Aquatic Science of Chongqing, Southwest University School of Life Sciences, Chongqing 400715, China.
| | - Yao-Guang Zhang
- Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Key Laboratory of Aquatic Science of Chongqing, Southwest University School of Life Sciences, Chongqing 400715, China.
| |
Collapse
|
6
|
Huang LJ, Chen RH. Lipid saturation induces degradation of squalene epoxidase for sterol homeostasis and cell survival. Life Sci Alliance 2022; 6:6/1/e202201612. [PMID: 36368908 PMCID: PMC9652772 DOI: 10.26508/lsa.202201612] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 10/24/2022] [Accepted: 10/25/2022] [Indexed: 11/13/2022] Open
Abstract
A fluid membrane containing a mix of unsaturated and saturated lipids is essential for life. However, it is unclear how lipid saturation might affect lipid homeostasis, membrane-associated proteins, and membrane organelles. Here, we generate temperature-sensitive mutants of the sole fatty acid desaturase gene OLE1 in the budding yeast Saccharomyces cerevisiae Using these mutants, we show that lipid saturation triggers the endoplasmic reticulum-associated degradation (ERAD) of squalene epoxidase Erg1, a rate-limiting enzyme in sterol biosynthesis, via the E3 ligase Doa10-Ubc7 complex. We identify the P469L mutation that abolishes the lipid saturation-induced ERAD of Erg1. Overexpressed WT or stable Erg1 mutants all mislocalize into foci in the ole1 mutant, whereas the stable Erg1 causes aberrant ER and severely compromises the growth of ole1, which are recapitulated by doa10 deletion. The toxicity of the stable Erg1 and doa10 deletion is due to the accumulation of lanosterol and misfolded proteins in ole1 Our study identifies Erg1 as a novel lipid saturation-regulated ERAD target, manifesting a close link between lipid homeostasis and proteostasis that maintains sterol homeostasis under the lipid saturation condition for cell survival.
Collapse
Affiliation(s)
| | - Rey-Huei Chen
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
| |
Collapse
|
7
|
Volkmar N, Gawden‐Bone CM, Williamson JC, Nixon‐Abell J, West JA, St George‐Hyslop PH, Kaser A, Lehner PJ. Regulation of membrane fluidity by RNF145-triggered degradation of the lipid hydrolase ADIPOR2. EMBO J 2022; 41:e110777. [PMID: 35993436 PMCID: PMC9531299 DOI: 10.15252/embj.2022110777] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 07/18/2022] [Accepted: 07/20/2022] [Indexed: 12/19/2022] Open
Abstract
The regulation of membrane lipid composition is critical for cellular homeostasis. Cells are particularly sensitive to phospholipid saturation, with increased saturation causing membrane rigidification and lipotoxicity. How mammalian cells sense membrane lipid composition and reverse fatty acid (FA)-induced membrane rigidification is poorly understood. Here we systematically identify proteins that differ between mammalian cells fed saturated versus unsaturated FAs. The most differentially expressed proteins were two ER-resident polytopic membrane proteins: the E3 ubiquitin ligase RNF145 and the lipid hydrolase ADIPOR2. In unsaturated lipid membranes, RNF145 is stable, promoting its lipid-sensitive interaction, ubiquitination and degradation of ADIPOR2. When membranes become enriched in saturated FAs, RNF145 is rapidly auto-ubiquitinated and degraded, stabilising ADIPOR2, whose hydrolase activity restores lipid homeostasis and prevents lipotoxicity. We therefore identify RNF145 as a FA-responsive ubiquitin ligase which, together with ADIPOR2, defines an autoregulatory pathway that controls cellular membrane lipid homeostasis and prevents acute lipotoxic stress.
Collapse
Affiliation(s)
- Norbert Volkmar
- Cambridge Institute of Therapeutic Immunology & Infectious Disease (CITIID), Jeffrey Cheah Biomedical CentreUniversity of CambridgeCambridgeUK
- Present address:
Institute for Molecular Systems Biology (IMSB)ETH ZürichZürichSwitzerland
| | - Christian M Gawden‐Bone
- Cambridge Institute of Therapeutic Immunology & Infectious Disease (CITIID), Jeffrey Cheah Biomedical CentreUniversity of CambridgeCambridgeUK
| | - James C Williamson
- Cambridge Institute of Therapeutic Immunology & Infectious Disease (CITIID), Jeffrey Cheah Biomedical CentreUniversity of CambridgeCambridgeUK
| | | | - James A West
- Cambridge Institute of Therapeutic Immunology & Infectious Disease (CITIID), Jeffrey Cheah Biomedical CentreUniversity of CambridgeCambridgeUK
| | | | - Arthur Kaser
- Cambridge Institute of Therapeutic Immunology & Infectious Disease (CITIID), Jeffrey Cheah Biomedical CentreUniversity of CambridgeCambridgeUK
| | - Paul J Lehner
- Cambridge Institute of Therapeutic Immunology & Infectious Disease (CITIID), Jeffrey Cheah Biomedical CentreUniversity of CambridgeCambridgeUK
| |
Collapse
|
8
|
Zhu Y, Lin X, Zhou X, Prochownik EV, Wang F, Li Y. Posttranslational control of lipogenesis in the tumor microenvironment. J Hematol Oncol 2022; 15:120. [PMID: 36038892 PMCID: PMC9422141 DOI: 10.1186/s13045-022-01340-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Accepted: 08/11/2022] [Indexed: 11/30/2022] Open
Abstract
Metabolic reprogramming of cancer cells within the tumor microenvironment typically occurs in response to increased nutritional, translation and proliferative demands. Altered lipid metabolism is a marker of tumor progression that is frequently observed in aggressive tumors with poor prognosis. Underlying these abnormal metabolic behaviors are posttranslational modifications (PTMs) of lipid metabolism-related enzymes and other factors that can impact their activity and/or subcellular localization. This review focuses on the roles of these PTMs and specifically on how they permit the re-wiring of cancer lipid metabolism, particularly within the context of the tumor microenvironment.
Collapse
Affiliation(s)
- Yahui Zhu
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, TaiKang Center for Life and Medical Sciences, Wuhan University, Wuhan, 430072, China.,Frontier Science Center for Immunology and Metabolism, Medical Research Institute, Wuhan University, Wuhan, 430071, China.,School of Medicine, Chongqing University, Chongqing, 400030, China
| | - Xingrong Lin
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, TaiKang Center for Life and Medical Sciences, Wuhan University, Wuhan, 430072, China.,Frontier Science Center for Immunology and Metabolism, Medical Research Institute, Wuhan University, Wuhan, 430071, China
| | - Xiaojun Zhou
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, TaiKang Center for Life and Medical Sciences, Wuhan University, Wuhan, 430072, China.,Frontier Science Center for Immunology and Metabolism, Medical Research Institute, Wuhan University, Wuhan, 430071, China
| | - Edward V Prochownik
- Division of Hematology/Oncology, Children's Hospital of Pittsburgh of UPMC, The Department of Microbiology and Molecular Genetics, The Pittsburgh Liver Research Center and The Hillman Cancer Center of UPMC, The University of Pittsburgh Medical Center, Pittsburgh, PA, 15224, USA
| | - Fubing Wang
- Department of Laboratory Medicine, Zhongnan Hospital of Wuhan University, Wuhan, 430072, China.
| | - Youjun Li
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, TaiKang Center for Life and Medical Sciences, Wuhan University, Wuhan, 430072, China. .,Frontier Science Center for Immunology and Metabolism, Medical Research Institute, Wuhan University, Wuhan, 430071, China.
| |
Collapse
|
9
|
Zou Y, Zhang H, Bi F, Tang Q, Xu H. Targeting the key cholesterol biosynthesis enzyme squalene monooxygenasefor cancer therapy. Front Oncol 2022; 12:938502. [PMID: 36091156 PMCID: PMC9449579 DOI: 10.3389/fonc.2022.938502] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Accepted: 07/26/2022] [Indexed: 11/22/2022] Open
Abstract
Cholesterol metabolism is often dysregulated in cancer. Squalene monooxygenase (SQLE) is the second rate-limiting enzyme involved in cholesterol synthesis. Since the discovery of SQLE dysregulation in cancer, compelling evidence has indicated that SQLE plays a vital role in cancer initiation and progression and is a promising therapeutic target for cancer treatment. In this review, we provide an overview of the role and regulation of SQLE in cancer and summarize the updates of antitumor therapy targeting SQLE.
Collapse
Affiliation(s)
- Yuheng Zou
- Department of Medical Oncology, Cancer Center and Laboratory of Molecular Targeted Therapy in Oncology, West China Hospital, Sichuan University, Chengdu, China
| | - Hongying Zhang
- Laboratory of Oncogene, West China Hospital, Sichuan University, Chengdu, China
| | - Feng Bi
- Department of Medical Oncology, Cancer Center and Laboratory of Molecular Targeted Therapy in Oncology, West China Hospital, Sichuan University, Chengdu, China
| | - Qiulin Tang
- Department of Medical Oncology, Cancer Center and Laboratory of Molecular Targeted Therapy in Oncology, West China Hospital, Sichuan University, Chengdu, China
- *Correspondence: Qiulin Tang, ; Huanji Xu,
| | - Huanji Xu
- Department of Medical Oncology, Cancer Center and Laboratory of Molecular Targeted Therapy in Oncology, West China Hospital, Sichuan University, Chengdu, China
- *Correspondence: Qiulin Tang, ; Huanji Xu,
| |
Collapse
|
10
|
Cao H, Xi S, He W, Ma X, Liu L, Xu J, Zhang K, Li Y, Jin L. The effects of Gentiana dahurica Fisch on alcoholic liver disease revealed by RNA sequencing. JOURNAL OF ETHNOPHARMACOLOGY 2021; 279:113422. [PMID: 33007391 DOI: 10.1016/j.jep.2020.113422] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2020] [Revised: 08/22/2020] [Accepted: 09/25/2020] [Indexed: 05/26/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE The root of Gentiana dahurica Fisch (called Qin-Jiao in China), a traditional Chinese medicine, is used in China to treat alcoholic liver disease (ALD), but there has been no scientific report on the treatment of ALD. AIM OF THE STUDY To investigate the therapeutic effects of Gentiana dahurica Fisch ethanol extract (GDEE) on ALD and to reveal its possible mechanism of action using RNA sequencing. MATERIALS AND METHODS The model of ALD was established by continuous gavage with alcohol in mice, and GDEE was used to treat ALD. Pathological observation (HE staining, oil red O staining) and biochemical indicators were performed to evaluate liver tissue lesions and efficacy of GDEE. RNA sequencing analysis of liver tissues was carried out to elucidate the pathogenesis of ALD and the mechanism of hepatoprotective effect by GDEE. The RNA sequencing results were verified by detecting mRNA and protein expressions of acetyl coenzyme A carboxylase α (Acacα), fatty acid synthase (Fasn) and carnitine palmitoyltransferase 1A (Cpt1a) by quantitative real-time polymerase chain reaction (PCR) and Western blot. RESULTS Measurements of biochemical parameters showed that GDEE could inhibit the increased transaminase activities in the serum and lipid levels in the liver caused by alcohol. It was observed that GDEE could alleviate fatty degeneration, edema and cell necrosis caused by alcohol in the liver tissue. RNA sequencing analysis of liver tissues found that 719 genes and 1137 genes were significantly changed by alcohol and GDEE, respectively. GDEE reversed most of the changes in triglycerides synthesis-related genes up-regulated by alcohol. GDEE up-regulated most of the genes involved in the fatty acid degradation in ALD mice, while alcohol had little effect on them. In addition, GDEE suppressed most of the genes involved in cholesterol synthesis that were up-regulated by alcohol. GDEE up-regulated genes related to bile acid synthesis in ALD mice, and down-regulated genes related to bile acid reabsorption, while alcohol had no significant effect on genes related to bile acid metabolism. In the validation experiments, the Acacα, Fasn and Cpt1a expressions quantified by real-time PCR and Western blot were consistent with the RNA sequencing results. CONCLUSIONS GDEE can alleviate liver damage and steatosis in ALD mice, and its mechanism of action may be related to the process of regulating triglycerides and cholesterol.
Collapse
Affiliation(s)
- Houkang Cao
- College of Pharmacy, Gansu University of Chinese Medicine, Lanzhou, Gansu, 730000, PR China.
| | - Shaoyang Xi
- College of Pharmacy, Gansu University of Chinese Medicine, Lanzhou, Gansu, 730000, PR China.
| | - Weiwei He
- College of Pharmacy, Gansu University of Chinese Medicine, Lanzhou, Gansu, 730000, PR China.
| | - Xiaohui Ma
- College of Pharmacy, Gansu University of Chinese Medicine, Lanzhou, Gansu, 730000, PR China.
| | - Li Liu
- College of Pharmacy, Gansu University of Chinese Medicine, Lanzhou, Gansu, 730000, PR China.
| | - Jie Xu
- College of Pharmacy, Guilin Medical University, Guilin, Guangxi, 541004, PR China.
| | - Kefeng Zhang
- College of Pharmacy, Guilin Medical University, Guilin, Guangxi, 541004, PR China.
| | - Yingdong Li
- College of Integration of Chinese and Western Medicine, Gansu University of Chinese Medicine, Lanzhou, Gansu, 730000, PR China.
| | - Ling Jin
- College of Pharmacy, Gansu University of Chinese Medicine, Lanzhou, Gansu, 730000, PR China.
| |
Collapse
|
11
|
Bian X, Liu R, Meng Y, Xing D, Xu D, Lu Z. Lipid metabolism and cancer. J Exp Med 2021; 218:211616. [PMID: 33601415 PMCID: PMC7754673 DOI: 10.1084/jem.20201606] [Citation(s) in RCA: 349] [Impact Index Per Article: 116.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 10/15/2020] [Accepted: 10/26/2020] [Indexed: 02/05/2023] Open
Abstract
Dysregulation in lipid metabolism is among the most prominent metabolic alterations in cancer. Cancer cells harness lipid metabolism to obtain energy, components for biological membranes, and signaling molecules needed for proliferation, survival, invasion, metastasis, and response to the tumor microenvironment impact and cancer therapy. Here, we summarize and discuss current knowledge about the advances made in understanding the regulation of lipid metabolism in cancer cells and introduce different approaches that have been clinically used to disrupt lipid metabolism in cancer therapy.
Collapse
Affiliation(s)
- Xueli Bian
- Cancer Institute of The Affiliated Hospital of Qingdao University and Qingdao Cancer Institute, Qingdao, China
| | - Rui Liu
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Chinese Academy of Medical Sciences Research Unit of Oral Carcinogenesis and Management, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Ying Meng
- Zhejiang Provincial Key Laboratory of Pancreatic Disease, The First Affiliated Hospital, and Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, China
| | - Dongming Xing
- Cancer Institute of The Affiliated Hospital of Qingdao University and Qingdao Cancer Institute, Qingdao, China.,School of Life Sciences, Tsinghua University, Beijing, China
| | - Daqian Xu
- Zhejiang Provincial Key Laboratory of Pancreatic Disease, The First Affiliated Hospital, and Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, China
| | - Zhimin Lu
- Zhejiang Provincial Key Laboratory of Pancreatic Disease, The First Affiliated Hospital, and Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, China.,Zhejiang University Cancer Center, Hangzhou, China
| |
Collapse
|
12
|
Madan B, Virshup DM, Nes WD, Leaver DJ. Unearthing the Janus-face cholesterogenesis pathways in cancer. Biochem Pharmacol 2021; 196:114611. [PMID: 34010597 DOI: 10.1016/j.bcp.2021.114611] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 05/12/2021] [Accepted: 05/13/2021] [Indexed: 12/23/2022]
Abstract
Cholesterol biosynthesis, primarily associated with eukaryotes, occurs as an essential component of human metabolism with biosynthetic deregulation a factor in cancer viability. The segment that partitions between squalene and the C27-end cholesterol yields the main cholesterogenesis branch subdivided into the Bloch and Kandutsch-Russell pathways. Their importance in cell viability, in normal growth and development originates primarily from the amphipathic property and shape of the cholesterol molecule which makes it suitable as a membrane insert. Cholesterol can also convert to variant oxygenated product metabolites of distinct function producing a complex interplay between cholesterol synthesis and overall steroidogenesis. In this review, we disassociate the two sides of cholesterogenesisis affecting the type and amounts of systemic sterols-one which is beneficial to human welfare while the other dysfunctional leading to misery and disease that could result in premature death. Our focus here is first to examine the cholesterol biosynthetic genes, enzymes, and order of biosynthetic intermediates in human cholesterogenesis pathways, then compare the effect of proximal and distal inhibitors of cholesterol biosynthesis against normal and cancer cell growth and metabolism. Collectively, the inhibitor studies of druggable enzymes and specific biosynthetic steps, suggest a potential role of disrupted cholesterol biosynthesis, in coordination with imported cholesterol, as a factor in cancer development and as discussed some of these inhibitors have chemotherapeutic implications.
Collapse
Affiliation(s)
- Babita Madan
- Program in Cancer and Stem Cell Biology, Duke-NUS Medical School, Singapore, Singapore
| | - David M Virshup
- Program in Cancer and Stem Cell Biology, Duke-NUS Medical School, Singapore, Singapore; Department of Pediatrics, Duke University, Durham, NC, USA
| | - W David Nes
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX, USA.
| | - David J Leaver
- Department of Biology, Geology, and Physical Sciences, Sul Ross State University, Alpine, TX, USA.
| |
Collapse
|
13
|
Coates HW, Capell-Hattam IM, Brown AJ. The mammalian cholesterol synthesis enzyme squalene monooxygenase is proteasomally truncated to a constitutively active form. J Biol Chem 2021; 296:100731. [PMID: 33933449 PMCID: PMC8166775 DOI: 10.1016/j.jbc.2021.100731] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 04/24/2021] [Accepted: 04/28/2021] [Indexed: 02/06/2023] Open
Abstract
Squalene monooxygenase (SM, also known as squalene epoxidase) is a rate-limiting enzyme of cholesterol synthesis that converts squalene to monooxidosqualene and is oncogenic in numerous cancer types. SM is subject to feedback regulation via cholesterol-induced proteasomal degradation, which depends on its lipid-sensing N-terminal regulatory domain. We previously identified an endogenous truncated form of SM with a similar abundance to full-length SM, but whether this truncated form is functional or subject to the same regulatory mechanisms as full-length SM is not known. Here, we show that truncated SM differs from full-length SM in two major ways: it is cholesterol resistant and adopts a peripheral rather than integral association with the endoplasmic reticulum membrane. However, truncated SM retains full SM activity and is therefore constitutively active. Truncation of SM occurs during its endoplasmic reticulum–associated degradation and requires the proteasome, which partially degrades the SM N-terminus and disrupts cholesterol-sensing elements within the regulatory domain. Furthermore, truncation relies on a ubiquitin signal that is distinct from that required for cholesterol-induced degradation. Using mutagenesis, we demonstrate that partial proteasomal degradation of SM depends on both an intrinsically disordered region near the truncation site and the stability of the adjacent catalytic domain, which escapes degradation. These findings uncover an additional layer of complexity in the post-translational regulation of cholesterol synthesis and establish SM as the first eukaryotic enzyme found to undergo proteasomal truncation.
Collapse
Affiliation(s)
- Hudson W Coates
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Sydney, NSW, Australia
| | | | - Andrew J Brown
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Sydney, NSW, Australia.
| |
Collapse
|
14
|
Weighted gene co-expression network analysis to identify key modules and hub genes related to hyperlipidaemia. Nutr Metab (Lond) 2021; 18:24. [PMID: 33663541 PMCID: PMC7934476 DOI: 10.1186/s12986-021-00555-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Accepted: 02/24/2021] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND The purpose of this study was to explore the potential molecular targets of hyperlipidaemia and the related molecular mechanisms. METHODS The microarray dataset of GSE66676 obtained from patients with hyperlipidaemia was downloaded. Weighted gene co-expression network (WGCNA) analysis was used to analyse the gene expression profile, and the royal blue module was considered to have the highest correlation. Gene Ontology (GO) functional and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were implemented for the identification of genes in the royal blue module using the Database for Annotation, Visualization and Integrated Discovery (DAVID) online tool (version 6.8; http://david.abcc.ncifcrf.gov ). A protein-protein interaction (PPI) network was established by using the online STRING tool. Then, several hub genes were identified by the MCODE and cytoHubba plug-ins in Cytoscape software. RESULTS The significant module (royal blue) identified was associated with TC, TG and non-HDL-C. GO and KEGG enrichment analyses revealed that the genes in the royal blue module were associated with carbon metabolism, steroid biosynthesis, fatty acid metabolism and biosynthesis pathways of unsaturated fatty acids. SQLE (degree = 17) was revealed as a key molecule associated with hypercholesterolaemia (HCH), and SCD was revealed as a key molecule associated with hypertriglyceridaemia (HTG). RT-qPCR analysis also confirmed the above results based on our HCH/HTG samples. CONCLUSIONS SQLE and SCD are related to hyperlipidaemia, and SQLE/SCD may be new targets for cholesterol-lowering or triglyceride-lowering therapy, respectively.
Collapse
|
15
|
The Degron Architecture of Squalene Monooxygenase and How Specific Lipids Calibrate Levels of This Key Cholesterol Synthesis Enzyme. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021. [PMID: 32979157 DOI: 10.1007/5584_2020_583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register]
Abstract
Cholesterol synthesis is a fundamental process that contributes to cellular cholesterol homeostasis. Cells execute transcriptional and post-translational mechanisms to control the abundance of enzymes of the cholesterol synthesis pathway, consequently affecting cholesterol production. One such highly tuned enzyme is squalene monooxygenase (SM), which catalyzes a rate-limiting step in the pathway. A well-characterized mechanism is the cholesterol-mediated degradation of SM. Notably, lipids (cholesterol, plasmalogens, squalene, and unsaturated fatty acids) can act as cellular signals that either promote or reduce SM degradation. The N-terminal region of SM consists of the shortest known cholesterol-responsive degron, characterized by atypical membrane anchoring structures, namely a re-entrant loop and an amphipathic helix. SM also undergoes non-canonical ubiquitination on serine, a relatively uncommon attachment site for ubiquitination. The structure of the catalytic domain of SM has been solved, providing insights into the catalytic mechanisms and modes of inhibition by well-known SM inhibitors, some of which have been effective in lowering cholesterol levels in animal models. Certain human cancers have been linked to dysregulation of SM levels and activity, further emphasizing the relevance of SM in health and disease.
Collapse
|
16
|
Sagatova AA. Strategies to Better Target Fungal Squalene Monooxygenase. J Fungi (Basel) 2021; 7:49. [PMID: 33450973 PMCID: PMC7828399 DOI: 10.3390/jof7010049] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2020] [Revised: 01/04/2021] [Accepted: 01/05/2021] [Indexed: 01/21/2023] Open
Abstract
Fungal pathogens present a challenge in medicine and agriculture. They also harm ecosystems and threaten biodiversity. The allylamine class of antimycotics targets the enzyme squalene monooxygenase. This enzyme occupies a key position in the sterol biosynthesis pathway in eukaryotes, catalyzing the rate-limiting reaction by introducing an oxygen atom to the squalene substrate converting it to 2,3-oxidosqualene. Currently, terbinafine-the most widely used allylamine-is mostly used for treating superficial fungal infections. The ability to better target this enzyme will have significant implications for human health in the treatment of fungal infections. The human orthologue can also be targeted for cholesterol-lowering therapeutics and in cancer therapies. This review will focus on the structural basis for improving the current therapeutics for fungal squalene monooxygenase.
Collapse
Affiliation(s)
- Alia A Sagatova
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| |
Collapse
|
17
|
Wangeline MA, Hampton RY. An autonomous, but INSIG-modulated, role for the sterol sensing domain in mallostery-regulated ERAD of yeast HMG-CoA reductase. J Biol Chem 2020; 296:100063. [PMID: 33184059 PMCID: PMC7948459 DOI: 10.1074/jbc.ra120.015910] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 11/01/2020] [Accepted: 11/12/2020] [Indexed: 01/23/2023] Open
Abstract
HMG-CoA reductase (HMGR) undergoes feedback-regulated degradation as part of sterol pathway control. Degradation of the yeast HMGR isozyme Hmg2 is controlled by the sterol pathway intermediate GGPP, which causes misfolding of Hmg2, leading to degradation by the HRD pathway; we call this process mallostery. We evaluated the role of the Hmg2 sterol sensing domain (SSD) in mallostery, as well as the involvement of the highly conserved INSIG proteins. We show that the Hmg2 SSD is critical for regulated degradation of Hmg2 and required for mallosteric misfolding of GGPP as studied by in vitro limited proteolysis. The Hmg2 SSD functions independently of conserved yeast INSIG proteins, but its function was modulated by INSIG, thus imposing a second layer of control on Hmg2 regulation. Mutant analyses indicated that SSD-mediated mallostery occurred prior to and independent of HRD-dependent ubiquitination. GGPP-dependent misfolding was still extant but occurred at a much slower rate in the absence of a functional SSD, indicating that the SSD facilitates a physiologically useful rate of GGPP response and implying that the SSD is not a binding site for GGPP. Nonfunctional SSD mutants allowed us to test the importance of Hmg2 quaternary structure in mallostery: a nonresponsive Hmg2 SSD mutant strongly suppressed regulation of a coexpressed, normal Hmg2. Finally, we have found that GGPP-regulated misfolding occurred in detergent-solubilized Hmg2, a feature that will allow next-level analysis of the mechanism of this novel tactic of ligand-regulated misfolding.
Collapse
Affiliation(s)
- Margaret A Wangeline
- Division of Biological Sciences, the Section of Cell and Developmental Biology, UCSD, La Jolla, California, USA
| | - Randolph Y Hampton
- Division of Biological Sciences, the Section of Cell and Developmental Biology, UCSD, La Jolla, California, USA.
| |
Collapse
|
18
|
Li S, Lin G, Fang W, Gao D, Huang J, Xie J, Lu J. Identification and Comparison of microRNAs in the Gonad of the Yellowfin Seabream ( Acanthopagrus Latus). Int J Mol Sci 2020; 21:E5690. [PMID: 32784462 PMCID: PMC7461063 DOI: 10.3390/ijms21165690] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 08/04/2020] [Accepted: 08/05/2020] [Indexed: 12/14/2022] Open
Abstract
Yellowfin seabream (Acanthopagrus latus) is a commercially important fish in Asian coastal waters. Although natural sex reversal has been described in yellowfin seabream, the mechanisms underlying sexual differentiation and gonadal development in this species remain unclear. MicroRNAs (miRNAs) have been shown to play crucial roles in gametogenesis and gonadal development. Here, two libraries of small RNAs, constructed from the testes and ovaries of yellowfin seabream, were sequenced. Across both gonads, we identified 324 conserved miRNAs and 92 novel miRNAs: 67 ovary-biased miRNAs, including the miR-200 families, the miR-29 families, miR-21, and miR-725; and 88 testis-biased miRNAs, including the let-7 families, the miR-10 families, miR-7, miR-9, and miR-202-3p. GO (Gene Ontology) annotations and KEGG (Kyoto Encyclopedia of Genes and Genomes) enrichment analyses of putative target genes indicated that many target genes were significantly enriched in the steroid biosynthesis pathway and in the reproductive process. Our integrated miRNA-mRNA analysis demonstrated a putative negatively correlated expression pattern in yellowfin seabream gonads. This study profiled the expression patterns of sex-biased miRNAs in yellowfin seabream gonads, and provided important molecular resources that will help to clarify the miRNA-mediated post-transcriptional regulation of sexual differentiation and gonadal development in this species.
Collapse
Affiliation(s)
- Shizhu Li
- School of Marine Sciences, Sun Yat-sen University, Zhuhai 519082, China; (S.L.); (G.L.); (W.F.); (D.G.); (J.H.); (J.X.)
| | - Genmei Lin
- School of Marine Sciences, Sun Yat-sen University, Zhuhai 519082, China; (S.L.); (G.L.); (W.F.); (D.G.); (J.H.); (J.X.)
| | - Wenyu Fang
- School of Marine Sciences, Sun Yat-sen University, Zhuhai 519082, China; (S.L.); (G.L.); (W.F.); (D.G.); (J.H.); (J.X.)
| | - Dong Gao
- School of Marine Sciences, Sun Yat-sen University, Zhuhai 519082, China; (S.L.); (G.L.); (W.F.); (D.G.); (J.H.); (J.X.)
| | - Jing Huang
- School of Marine Sciences, Sun Yat-sen University, Zhuhai 519082, China; (S.L.); (G.L.); (W.F.); (D.G.); (J.H.); (J.X.)
| | - Jingui Xie
- School of Marine Sciences, Sun Yat-sen University, Zhuhai 519082, China; (S.L.); (G.L.); (W.F.); (D.G.); (J.H.); (J.X.)
| | - Jianguo Lu
- School of Marine Sciences, Sun Yat-sen University, Zhuhai 519082, China; (S.L.); (G.L.); (W.F.); (D.G.); (J.H.); (J.X.)
- Southern Marine Sciences and Engineering Guangdong Laboratory, Zhuhai 519082, China
| |
Collapse
|
19
|
Chua NK, Coates HW, Brown AJ. Squalene monooxygenase: a journey to the heart of cholesterol synthesis. Prog Lipid Res 2020; 79:101033. [DOI: 10.1016/j.plipres.2020.101033] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 04/21/2020] [Accepted: 04/24/2020] [Indexed: 02/07/2023]
|
20
|
The cholesterol synthesis enzyme lanosterol 14α-demethylase is post-translationally regulated by the E3 ubiquitin ligase MARCH6. Biochem J 2020; 477:541-555. [PMID: 31904814 PMCID: PMC6993871 DOI: 10.1042/bcj20190647] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Revised: 12/22/2019] [Accepted: 01/02/2020] [Indexed: 01/07/2023]
Abstract
Cholesterol synthesis is a tightly controlled pathway, with over 20 enzymes involved. Each of these enzymes can be distinctly regulated, helping to fine-tune the production of cholesterol and its functional intermediates. Several enzymes are degraded in response to increased sterol levels, whilst others remain stable. We hypothesised that an enzyme at a key branch point in the pathway, lanosterol 14α-demethylase (LDM) may be post-translationally regulated. Here, we show that the preceding enzyme, lanosterol synthase is stable, whilst LDM is rapidly degraded. Surprisingly, this degradation is not triggered by sterols. However, the E3 ubiquitin ligase membrane-associated ring-CH-type finger 6 (MARCH6), known to control earlier rate-limiting steps in cholesterol synthesis, also control levels of LDM and the terminal cholesterol synthesis enzyme, 24-dehydrocholesterol reductase. Our work highlights MARCH6 as the first example of an E3 ubiquitin ligase that targets multiple steps in a biochemical pathway and indicates new facets in the control of cholesterol synthesis.
Collapse
|
21
|
van den Boomen DJH, Volkmar N, Lehner PJ. Ubiquitin-mediated regulation of sterol homeostasis. Curr Opin Cell Biol 2020; 65:103-111. [PMID: 32580085 DOI: 10.1016/j.ceb.2020.04.010] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2020] [Revised: 04/03/2020] [Accepted: 04/26/2020] [Indexed: 11/19/2022]
Abstract
Cholesterol is an essential component of mammalian membranes, and its homeostasis is strictly regulated, with imbalances causing atherosclerosis, Niemann Pick disease, and familial hypercholesterolemia. Cellular cholesterol supply is mediated by LDL-cholesterol import and de novo cholesterol biosynthesis, and both pathways are adjusted to cellular demand by the cholesterol-sensitive SREBP2 transcription factor. Cholesterol homeostasis is modulated by a wide variety of metabolic pathways and the ubiquitination machinery, in particular E3 ubiquitin ligases. In this article, we review recent progress in understanding the role of E3 ubiquitin ligases in the metabolic control of cellular sterol homeostasis.
Collapse
Affiliation(s)
- Dick J H van den Boomen
- Cambridge Institute of Therapeutic Immunology & Infectious Disease, University of Cambridge, Cambridge, United Kingdom
| | - Norbert Volkmar
- Cambridge Institute of Therapeutic Immunology & Infectious Disease, University of Cambridge, Cambridge, United Kingdom
| | - Paul J Lehner
- Cambridge Institute of Therapeutic Immunology & Infectious Disease, University of Cambridge, Cambridge, United Kingdom.
| |
Collapse
|
22
|
A key mammalian cholesterol synthesis enzyme, squalene monooxygenase, is allosterically stabilized by its substrate. Proc Natl Acad Sci U S A 2020; 117:7150-7158. [PMID: 32170014 PMCID: PMC7132291 DOI: 10.1073/pnas.1915923117] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Cholesterol biosynthesis is a high-cost process and, therefore, tightly regulated by both transcriptional and posttranslational negative feedback mechanisms in response to the level of cellular cholesterol. Squalene monooxygenase (SM, also known as squalene epoxidase or SQLE) is a rate-limiting enzyme in the cholesterol biosynthetic pathway and catalyzes epoxidation of squalene. The stability of SM is negatively regulated by cholesterol via its N-terminal regulatory domain (SM-N100). In this study, using a SM-luciferase fusion reporter cell line, we performed a chemical genetics screen that identified inhibitors of SM itself as up-regulators of SM. This effect was mediated through the SM-N100 region, competed with cholesterol-accelerated degradation, and required the E3 ubiquitin ligase MARCH6. However, up-regulation was not observed with statins, well-established cholesterol biosynthesis inhibitors, and this pointed to the presence of another mechanism other than reduced cholesterol synthesis. Further analyses revealed that squalene accumulation upon treatment with the SM inhibitor was responsible for the up-regulatory effect. Using photoaffinity labeling, we demonstrated that squalene directly bound to the N100 region, thereby reducing interaction with and ubiquitination by MARCH6. Our findings suggest that SM senses squalene via its N100 domain to increase its metabolic capacity, highlighting squalene as a feedforward factor for the cholesterol biosynthetic pathway.
Collapse
|
23
|
Valosin-containing protein mediates the ERAD of squalene monooxygenase and its cholesterol-responsive degron. Biochem J 2019; 476:2545-2560. [DOI: 10.1042/bcj20190418] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Revised: 08/27/2019] [Accepted: 08/29/2019] [Indexed: 12/17/2022]
Abstract
AbstractSqualene monooxygenase (SM) is an essential rate-limiting enzyme in cholesterol synthesis. SM degradation is accelerated by excess cholesterol, and this requires the first 100 amino acids of SM (SM N100). This process is part of a protein quality control pathway called endoplasmic reticulum-associated degradation (ERAD). In ERAD, SM is ubiquitinated by MARCH6, an E3 ubiquitin ligase located in the endoplasmic reticulum (ER). However, several details of the ERAD process for SM remain elusive, such as the extraction mechanism from the ER membrane. Here, we used SM N100 fused to GFP (SM N100-GFP) as a model degron to investigate the extraction process of SM in ERAD. We showed that valosin-containing protein (VCP) is important for the cholesterol-accelerated degradation of SM N100-GFP and SM. In addition, we revealed that VCP acts following ubiquitination of SM N100-GFP by MARCH6. We demonstrated that the amphipathic helix (Gln62–Leu73) of SM N100-GFP is critical for regulation by VCP and MARCH6. Replacing this amphipathic helix with hydrophobic re-entrant loops promoted degradation in a VCP-dependent manner. Finally, we showed that inhibiting VCP increases cellular squalene and cholesterol levels, indicating a functional consequence for VCP in regulating the cholesterol synthesis pathway. Collectively, we established VCP plays a key role in ERAD that contributes to the cholesterol-mediated regulation of SM.
Collapse
|
24
|
Volkmar N, Thezenas ML, Louie SM, Juszkiewicz S, Nomura DK, Hegde RS, Kessler BM, Christianson JC. The ER membrane protein complex promotes biogenesis of sterol-related enzymes maintaining cholesterol homeostasis. J Cell Sci 2019; 132:jcs.223453. [PMID: 30578317 PMCID: PMC6362398 DOI: 10.1242/jcs.223453] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Accepted: 12/03/2018] [Indexed: 12/24/2022] Open
Abstract
The eukaryotic endoplasmic reticulum (ER) membrane contains essential complexes that oversee protein biogenesis and lipid metabolism, impacting nearly all aspects of cell physiology. The ER membrane protein complex (EMC) is a newly described transmembrane domain (TMD) insertase linked with various phenotypes, but whose clients and cellular responsibilities remain incompletely understood. We report that EMC deficiency limits the cellular boundaries defining cholesterol tolerance, reflected by diminished viability with limiting or excessive extracellular cholesterol. Lipidomic and proteomic analyses revealed defective biogenesis and concomitant loss of the TMD-containing ER-resident enzymes sterol-O-acyltransferase 1 (SOAT1) and squalene synthase (SQS, also known as FDFT1), which serve strategic roles in the adaptation of cells to changes in cholesterol availability. Insertion of the weakly hydrophobic tail-anchor (TA) of SQS into the ER membrane by the EMC ensures sufficient flux through the sterol biosynthetic pathway while biogenesis of polytopic SOAT1 promoted by the EMC provides cells with the ability to store free cholesterol as inert cholesteryl esters. By facilitating insertion of TMDs that permit essential mammalian sterol-regulating enzymes to mature accurately, the EMC is an important biogenic determinant of cellular robustness to fluctuations in cholesterol availability. This article has an associated First Person interview with the first author of the paper. Highlighted Article: The ER membrane protein complex promotes biogenesis of key membrane-bound enzymes responsible for regulation of cholesterol biosynthesis and storage, an important determinant of mammalian cell viability.
Collapse
Affiliation(s)
- Norbert Volkmar
- Ludwig Institute for Cancer Research, University of Oxford, ORCRB, Headington, Oxford, OX3 7DQ, UK
| | - Maria-Laetitia Thezenas
- Target Discovery Institute (TDI) Mass Spectrometry Laboratory, Nuffield Department of Medicine, University of Oxford, Headington, Oxford, OX3 7DQ, UK
| | - Sharon M Louie
- Dept. of Chemistry, Molecular and Cell Biology, and Nutritional Sciences and Toxicology, University of California-Berkeley, Berkeley, CA, 94720, USA
| | - Szymon Juszkiewicz
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Daniel K Nomura
- Dept. of Chemistry, Molecular and Cell Biology, and Nutritional Sciences and Toxicology, University of California-Berkeley, Berkeley, CA, 94720, USA
| | - Ramanujan S Hegde
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Benedikt M Kessler
- Target Discovery Institute (TDI) Mass Spectrometry Laboratory, Nuffield Department of Medicine, University of Oxford, Headington, Oxford, OX3 7DQ, UK
| | - John C Christianson
- Ludwig Institute for Cancer Research, University of Oxford, ORCRB, Headington, Oxford, OX3 7DQ, UK .,Oxford Centre for Translational Myeloma Research, NDORMS, University of Oxford, Botnar Research Centre, Headington, Oxford, OX3 7LD, UK
| |
Collapse
|
25
|
Padyana AK, Gross S, Jin L, Cianchetta G, Narayanaswamy R, Wang F, Wang R, Fang C, Lv X, Biller SA, Dang L, Mahoney CE, Nagaraja N, Pirman D, Sui Z, Popovici-Muller J, Smolen GA. Structure and inhibition mechanism of the catalytic domain of human squalene epoxidase. Nat Commun 2019; 10:97. [PMID: 30626872 PMCID: PMC6327030 DOI: 10.1038/s41467-018-07928-x] [Citation(s) in RCA: 73] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Accepted: 12/04/2018] [Indexed: 12/22/2022] Open
Abstract
Squalene epoxidase (SQLE), also known as squalene monooxygenase, catalyzes the stereospecific conversion of squalene to 2,3(S)-oxidosqualene, a key step in cholesterol biosynthesis. SQLE inhibition is targeted for the treatment of hypercholesteremia, cancer, and fungal infections. However, lack of structure-function understanding has hindered further progression of its inhibitors. We have determined the first three-dimensional high-resolution crystal structures of human SQLE catalytic domain with small molecule inhibitors (2.3 Å and 2.5 Å). Comparison with its unliganded state (3.0 Å) reveals conformational rearrangements upon inhibitor binding, thus allowing deeper interpretation of known structure-activity relationships. We use the human SQLE structure to further understand the specificity of terbinafine, an approved agent targeting fungal SQLE, and to provide the structural insights into terbinafine-resistant mutants encountered in the clinic. Collectively, these findings elucidate the structural basis for the specificity of the epoxidation reaction catalyzed by SQLE and enable further rational development of next-generation inhibitors.
Collapse
Affiliation(s)
- Anil K Padyana
- Agios Pharmaceuticals, 88 Sidney Street, Cambridge, MA, 02139, USA.
| | - Stefan Gross
- Agios Pharmaceuticals, 88 Sidney Street, Cambridge, MA, 02139, USA
| | - Lei Jin
- Agile Biostructure Solutions Consulting, LLC, 8 Harris Ave, Wellesley, MA, 02481, USA
| | - Giovanni Cianchetta
- Agios Pharmaceuticals, 88 Sidney Street, Cambridge, MA, 02139, USA
- KSQ Therapeutics, 610 Main St, Cambridge, MA, 02139, USA
| | | | - Feng Wang
- Wuxi Biortus Biosciences Co. Ltd., 6 Dongsheng West Road, Jiangyin, 214437, China
| | - Rui Wang
- Wuxi Biortus Biosciences Co. Ltd., 6 Dongsheng West Road, Jiangyin, 214437, China
- Department of Stomatology, Xiamen University, 361102, Xiamen, China
| | - Cheng Fang
- Shanghai ChemPartner Co. Ltd., 998 Halei Road, 201203, Shanghai, China
| | - Xiaobing Lv
- Shanghai ChemPartner Co. Ltd., 998 Halei Road, 201203, Shanghai, China
- Sundia MediTech Company, Ltd., 917 Halei Road, 201203, Shanghai, China
| | - Scott A Biller
- Agios Pharmaceuticals, 88 Sidney Street, Cambridge, MA, 02139, USA
| | - Lenny Dang
- Agios Pharmaceuticals, 88 Sidney Street, Cambridge, MA, 02139, USA
| | | | | | - David Pirman
- Agios Pharmaceuticals, 88 Sidney Street, Cambridge, MA, 02139, USA
| | - Zhihua Sui
- Agios Pharmaceuticals, 88 Sidney Street, Cambridge, MA, 02139, USA
| | - Janeta Popovici-Muller
- Agios Pharmaceuticals, 88 Sidney Street, Cambridge, MA, 02139, USA
- Decibel Therapeutics, 1325 Boylston St Suite 500, Boston, MA, 02215, USA
| | - Gromoslaw A Smolen
- Agios Pharmaceuticals, 88 Sidney Street, Cambridge, MA, 02139, USA
- Celsius Therapeutics, 215 First Street, Cambridge, MA, 02142, USA
| |
Collapse
|
26
|
Tan JME, Cook ECL, van den Berg M, Scheij S, Zelcer N, Loregger A. Differential use of E2 ubiquitin conjugating enzymes for regulated degradation of the rate-limiting enzymes HMGCR and SQLE in cholesterol biosynthesis. Atherosclerosis 2018; 281:137-142. [PMID: 30658189 DOI: 10.1016/j.atherosclerosis.2018.12.008] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Revised: 12/03/2018] [Accepted: 12/13/2018] [Indexed: 11/16/2022]
Abstract
BACKGROUND AND AIMS Cholesterol is an essential lipid for cellular function and membrane integrity, and hence its cellular levels and distribution must be tightly regulated. Biosynthesis of cholesterol is ramped when its cellular levels are low. Herein, the ER-resident and rate-limiting enzymes 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGCR) and squalene monooxygenase (SQLE) play a prominent role. We have recently reported that MARCH6, an E3 ubiquitin ligase, specifically promotes cholesterol-stimulated ubiquitylation and subsequent proteasomal degradation of SQLE, but not of HMGCR. To further delineate how post-translational regulation of SQLE and HMGCR is differentially achieved, we hypothesized that their sterol-dependent degradation machinery makes use of distinct E2 ubiquitin conjugating enzymes. METHODS To study this possibility, we therefore used a CRISPR/Cas9-based approach to screen for ER-associated degradation (ERAD)-associated E2 enzymes that are essential for MARCH6-dependent degradation of SQLE. RESULTS We report here the identification of UBE2J2 as the primary E2 ubiquitin conjugating enzyme essential for this process in mammalian cells, in contrast to UBE2G2, which is essential for sterol-stimulated degradation of HMGCR. We demonstrate that ablating UBE2J2 disturbs cholesterol-accelerated SQLE degradation in multiple human cell types, including cells of hepatic origin, and that the ability of UBE2J2 to support SQLE degradation critically depends on its enzymatic activity. CONCLUSIONS Our findings establish UBE2J2 as an important partner of MARCH6 in cholesterol-stimulated degradation of SQLE, thereby contributing to the complex regulation of cellular cholesterol homeostasis.
Collapse
Affiliation(s)
- Josephine M E Tan
- Department of Medical Biochemistry, Academic Medical Center, University of Amsterdam, Meibergdreef 15, 1105 AZ, Amsterdam, the Netherlands
| | - Emma C L Cook
- Department of Medical Biochemistry, Academic Medical Center, University of Amsterdam, Meibergdreef 15, 1105 AZ, Amsterdam, the Netherlands
| | - Marlene van den Berg
- Department of Medical Biochemistry, Academic Medical Center, University of Amsterdam, Meibergdreef 15, 1105 AZ, Amsterdam, the Netherlands
| | - Saskia Scheij
- Department of Medical Biochemistry, Academic Medical Center, University of Amsterdam, Meibergdreef 15, 1105 AZ, Amsterdam, the Netherlands
| | - Noam Zelcer
- Department of Medical Biochemistry, Academic Medical Center, University of Amsterdam, Meibergdreef 15, 1105 AZ, Amsterdam, the Netherlands.
| | - Anke Loregger
- Department of Medical Biochemistry, Academic Medical Center, University of Amsterdam, Meibergdreef 15, 1105 AZ, Amsterdam, the Netherlands.
| |
Collapse
|
27
|
Samant RS, Livingston CM, Sontag EM, Frydman J. Distinct proteostasis circuits cooperate in nuclear and cytoplasmic protein quality control. Nature 2018; 563:407-411. [PMID: 30429547 PMCID: PMC6707801 DOI: 10.1038/s41586-018-0678-x] [Citation(s) in RCA: 115] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Accepted: 09/04/2018] [Indexed: 11/09/2022]
Abstract
Protein misfolding is linked to a wide array of human disorders, including Alzheimer's disease, Parkinson's disease and type II diabetes1,2. Protective cellular protein quality control (PQC) mechanisms have evolved to selectively recognize misfolded proteins and limit their toxic effects3-9, thus contributing to the maintenance of the proteome (proteostasis). Here we examine how molecular chaperones and the ubiquitin-proteasome system cooperate to recognize and promote the clearance of soluble misfolded proteins. Using a panel of PQC substrates with distinct characteristics and localizations, we define distinct chaperone and ubiquitination circuitries that execute quality control in the cytoplasm and nucleus. In the cytoplasm, proteasomal degradation of misfolded proteins requires tagging with mixed lysine 48 (K48)- and lysine 11 (K11)-linked ubiquitin chains. A distinct combination of E3 ubiquitin ligases and specific chaperones is required to achieve each type of linkage-specific ubiquitination. In the nucleus, however, proteasomal degradation of misfolded proteins requires only K48-linked ubiquitin chains, and is thus independent of K11-specific ligases and chaperones. The distinct ubiquitin codes for nuclear and cytoplasmic PQC appear to be linked to the function of the ubiquilin protein Dsk2, which is specifically required to clear nuclear misfolded proteins. Our work defines the principles of cytoplasmic and nuclear PQC as distinct, involving combinatorial recognition by defined sets of cooperating chaperones and E3 ligases. A better understanding of how these organelle-specific PQC requirements implement proteome integrity has implications for our understanding of diseases linked to impaired protein clearance and proteostasis dysfunction.
Collapse
Affiliation(s)
- Rahul S Samant
- Department of Biology, Stanford University, Stanford, CA, USA.
| | - Christine M Livingston
- Department of Biology, Stanford University, Stanford, CA, USA. .,Janssen Research and Development, Spring House, PA, USA.
| | - Emily M Sontag
- Department of Biology, Stanford University, Stanford, CA, USA
| | - Judith Frydman
- Department of Biology, Stanford University, Stanford, CA, USA. .,Department of Genetics, Stanford University, Stanford, CA, USA.
| |
Collapse
|
28
|
Coordinate regulation of mutant NPC1 degradation by selective ER autophagy and MARCH6-dependent ERAD. Nat Commun 2018; 9:3671. [PMID: 30202070 PMCID: PMC6131187 DOI: 10.1038/s41467-018-06115-2] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Accepted: 07/26/2018] [Indexed: 12/30/2022] Open
Abstract
Niemann–Pick type C disease is a fatal, progressive neurodegenerative disorder caused by loss-of-function mutations in NPC1, a multipass transmembrane glycoprotein essential for intracellular lipid trafficking. We sought to define the cellular machinery controlling degradation of the most common disease-causing mutant, I1061T NPC1. We show that this mutant is degraded, in part, by the proteasome following MARCH6-dependent ERAD. Unexpectedly, we demonstrate that I1061T NPC1 is also degraded by a recently described autophagic pathway called selective ER autophagy (ER-phagy). We establish the importance of ER-phagy both in vitro and in vivo, and identify I1061T as a misfolded endogenous substrate for this FAM134B-dependent process. Subcellular fractionation of I1061T Npc1 mouse tissues and analysis of human samples show alterations of key components of ER-phagy, including FAM134B. Our data establish that I1061T NPC1 is recognized in the ER and degraded by two different pathways that function in a complementary fashion to regulate protein turnover. Niemann-Pick type C1 disease is most commonly caused by the allele NPC1 I1061T, which is misfolded in the ER and rapidly degraded by the ubiquitin proteasome system. Here the authors show that the I1061T mutant is also degraded by ER-phagy.
Collapse
|
29
|
The cancer-associated microprotein CASIMO1 controls cell proliferation and interacts with squalene epoxidase modulating lipid droplet formation. Oncogene 2018; 37:4750-4768. [DOI: 10.1038/s41388-018-0281-5] [Citation(s) in RCA: 99] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Revised: 03/29/2018] [Accepted: 04/02/2018] [Indexed: 01/26/2023]
|
30
|
Chen J, Guccini I, Di Mitri D, Brina D, Revandkar A, Sarti M, Pasquini E, Alajati A, Pinton S, Losa M, Civenni G, Catapano CV, Sgrignani J, Cavalli A, D'Antuono R, Asara JM, Morandi A, Chiarugi P, Crotti S, Agostini M, Montopoli M, Masgras I, Rasola A, Garcia-Escudero R, Delaleu N, Rinaldi A, Bertoni F, Bono JD, Carracedo A, Alimonti A. Compartmentalized activities of the pyruvate dehydrogenase complex sustain lipogenesis in prostate cancer. Nat Genet 2018; 50:219-228. [PMID: 29335542 PMCID: PMC5810912 DOI: 10.1038/s41588-017-0026-3] [Citation(s) in RCA: 113] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Accepted: 12/01/2017] [Indexed: 11/21/2022]
Abstract
The mechanisms by which mitochondrial metabolism supports cancer anabolism remain unclear. Here, we found that genetic and pharmacological inactivation of pyruvate dehydrogenase A1 (PDHA1), a subunit of the pyruvate dehydrogenase complex (PDC), inhibits prostate cancer development in mouse and human xenograft tumor models by affecting lipid biosynthesis. Mechanistically, we show that in prostate cancer, PDC localizes in both the mitochondria and the nucleus. Whereas nuclear PDC controls the expression of sterol regulatory element-binding transcription factor (SREBF)-target genes by mediating histone acetylation, mitochondrial PDC provides cytosolic citrate for lipid synthesis in a coordinated manner, thereby sustaining anabolism. Additionally, we found that PDHA1 and the PDC activator pyruvate dehydrogenase phosphatase 1 (PDP1) are frequently amplified and overexpressed at both the gene and protein levels in prostate tumors. Together, these findings demonstrate that both mitochondrial and nuclear PDC sustain prostate tumorigenesis by controlling lipid biosynthesis, thus suggesting this complex as a potential target for cancer therapy.
Collapse
Affiliation(s)
- Jingjing Chen
- Institute of Oncology Research, Oncology Institute of Southern Switzerland, Università della Svizzera Italiana, Bellinzona, Switzerland
- Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Ilaria Guccini
- Institute of Oncology Research, Oncology Institute of Southern Switzerland, Università della Svizzera Italiana, Bellinzona, Switzerland
| | - Diletta Di Mitri
- Institute of Oncology Research, Oncology Institute of Southern Switzerland, Università della Svizzera Italiana, Bellinzona, Switzerland
| | - Daniela Brina
- Institute of Oncology Research, Oncology Institute of Southern Switzerland, Università della Svizzera Italiana, Bellinzona, Switzerland
| | - Ajinkya Revandkar
- Institute of Oncology Research, Oncology Institute of Southern Switzerland, Università della Svizzera Italiana, Bellinzona, Switzerland
- Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Manuela Sarti
- Institute of Oncology Research, Oncology Institute of Southern Switzerland, Università della Svizzera Italiana, Bellinzona, Switzerland
| | - Emiliano Pasquini
- Institute of Oncology Research, Oncology Institute of Southern Switzerland, Università della Svizzera Italiana, Bellinzona, Switzerland
| | - Abdullah Alajati
- Institute of Oncology Research, Oncology Institute of Southern Switzerland, Università della Svizzera Italiana, Bellinzona, Switzerland
| | - Sandra Pinton
- Institute of Oncology Research, Oncology Institute of Southern Switzerland, Università della Svizzera Italiana, Bellinzona, Switzerland
| | - Marco Losa
- Institute of Oncology Research, Oncology Institute of Southern Switzerland, Università della Svizzera Italiana, Bellinzona, Switzerland
| | - Gianluca Civenni
- Institute of Oncology Research, Oncology Institute of Southern Switzerland, Università della Svizzera Italiana, Bellinzona, Switzerland
| | - Carlo V Catapano
- Institute of Oncology Research, Oncology Institute of Southern Switzerland, Università della Svizzera Italiana, Bellinzona, Switzerland
| | - Jacopo Sgrignani
- Computational Structural Biology, Institute for Research in Biomedicine, Università della Svizzera Italiana, Bellinzona, Switzerland
| | - Andrea Cavalli
- Computational Structural Biology, Institute for Research in Biomedicine, Università della Svizzera Italiana, Bellinzona, Switzerland
| | - Rocco D'Antuono
- Imaging Facility, Institute for Research in Biomedicine, Università della Svizzera Italiana, Bellinzona, Switzerland
| | - John M Asara
- Division of Signal Transduction, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA
| | - Andrea Morandi
- Department of Biomedical, Experimental and Clinical Sciences, University of Florence, Florence, Italy
| | - Paola Chiarugi
- Department of Biomedical, Experimental and Clinical Sciences, University of Florence, Florence, Italy
| | - Sara Crotti
- Nano-inspired Biomedicine Lab, Institute of Paediatric Research-Città della Speranza, Padova, Italy
| | - Marco Agostini
- Nano-inspired Biomedicine Lab, Institute of Paediatric Research-Città della Speranza, Padova, Italy
- Surgical Clinic, Department of Surgical, Oncological and Gastroenterological Sciences, University of Padova, Padova, Italy
| | - Monica Montopoli
- Department of Pharmaceutical and Pharmacological Sciences, University of Padova, Padova, Italy
| | - Ionica Masgras
- CNR Institute of Neuroscience and Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Andrea Rasola
- CNR Institute of Neuroscience and Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Ramon Garcia-Escudero
- Molecular Oncology Unit, Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas, Madrid, Spain
- Biomedical Research Institute I+12, University Hospital 12 de Octubre, Madrid, Spain
- Centro de Investigación Biomédica en Red de Cáncer, Madrid, Spain
| | - Nicolas Delaleu
- Roegelmann Research Laboratory, Department of Clinical Science, University of Bergen, Bergen, Norway
| | - Andrea Rinaldi
- Institute of Oncology Research, Oncology Institute of Southern Switzerland, Università della Svizzera Italiana, Bellinzona, Switzerland
| | - Francesco Bertoni
- Institute of Oncology Research, Oncology Institute of Southern Switzerland, Università della Svizzera Italiana, Bellinzona, Switzerland
| | - Johann de Bono
- Drug Development Unit, Division of Cancer Therapeutics and Division of Clinical Studies, Royal Marsden NHS Foundation Trust and Institute of Cancer Research, London, UK
| | - Arkaitz Carracedo
- Centro de Investigación Biomédica en Red de Cáncer, Madrid, Spain
- CIC bioGUNE, Bizkaia Technology Park, Bizkaia, Spain
- Ikerbasque, Basque Foundation for Science, Bilbao, Spain
- Biochemistry and Molecular Biology Department, University of the Basque Country, Bilbao, Spain
| | - Andrea Alimonti
- Institute of Oncology Research, Oncology Institute of Southern Switzerland, Università della Svizzera Italiana, Bellinzona, Switzerland.
- Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland.
- Department of Medicine, Venetian Institute of Molecular Medicine, University of Padova, Padova, Italy.
| |
Collapse
|
31
|
Abstract
The endoplasmic reticulum is the port of entry for proteins into the secretory pathway and the site of synthesis for several important lipids, including cholesterol, triacylglycerol, and phospholipids. Protein production within the endoplasmic reticulum is tightly regulated by a cohort of resident machinery that coordinates the folding, modification, and deployment of secreted and integral membrane proteins. Proteins failing to attain their native conformation are degraded through the endoplasmic reticulum-associated degradation (ERAD) pathway via a series of tightly coupled steps: substrate recognition, dislocation, and ubiquitin-dependent proteasomal destruction. The same ERAD machinery also controls the flux through various metabolic pathways by coupling the turnover of metabolic enzymes to the levels of key metabolites. We review the current understanding and biological significance of ERAD-mediated regulation of lipid metabolism in mammalian cells.
Collapse
Affiliation(s)
- Julian Stevenson
- Program in Metabolic Biology, Department of Nutritional Sciences and Toxicology, University of California, Berkeley, California 94720;
| | - Edmond Y Huang
- Program in Metabolic Biology, Department of Nutritional Sciences and Toxicology, University of California, Berkeley, California 94720;
| | - James A Olzmann
- Program in Metabolic Biology, Department of Nutritional Sciences and Toxicology, University of California, Berkeley, California 94720;
| |
Collapse
|
32
|
Howe V, Sharpe LJ, Alexopoulos SJ, Kunze SV, Chua NK, Li D, Brown AJ. Cholesterol homeostasis: How do cells sense sterol excess? Chem Phys Lipids 2016; 199:170-178. [PMID: 26993747 DOI: 10.1016/j.chemphyslip.2016.02.011] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Accepted: 02/27/2016] [Indexed: 12/23/2022]
Abstract
Cholesterol is vital in mammals, but toxic in excess. Consequently, elaborate molecular mechanisms have evolved to maintain this sterol within narrow limits. How cells sense excess cholesterol is an intriguing area of research. Cells sense cholesterol, and other related sterols such as oxysterols or cholesterol synthesis intermediates, and respond to changing levels through several elegant mechanisms of feedback regulation. Cholesterol sensing involves both direct binding of sterols to the homeostatic machinery located in the endoplasmic reticulum (ER), and indirect effects elicited by sterol-dependent alteration of the physical properties of membranes. Here, we examine the mechanisms employed by cells to maintain cholesterol homeostasis.
Collapse
Affiliation(s)
- Vicky Howe
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, NSW, Australia
| | - Laura J Sharpe
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, NSW, Australia
| | - Stephanie J Alexopoulos
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, NSW, Australia
| | - Sarah V Kunze
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, NSW, Australia
| | - Ngee Kiat Chua
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, NSW, Australia
| | - Dianfan Li
- National Center for Protein Sciences, State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Andrew J Brown
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, NSW, Australia.
| |
Collapse
|
33
|
Sharpe LJ, Cook ECL, Zelcer N, Brown AJ. The UPS and downs of cholesterol homeostasis. Trends Biochem Sci 2014; 39:527-35. [PMID: 25220377 DOI: 10.1016/j.tibs.2014.08.008] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Revised: 08/18/2014] [Accepted: 08/21/2014] [Indexed: 11/26/2022]
Abstract
An emerging theme in the regulation of cholesterol homeostasis is the role of the ubiquitin proteasome system (UPS), through which proteins are ubiquitylated and then degraded in response to specific signals. The UPS controls all aspects of cholesterol metabolism including its synthesis, uptake, and efflux. We review here recent work uncovering the ubiquitylation and degradation of key players in cholesterol homeostasis. This includes the low-density lipoprotein (LDL) receptor, transcription factors (sterol regulatory element binding proteins and liver X receptors), flux-controlling enzymes in cholesterol synthesis (3-hydroxy-3-methylglutaryl-CoA reductase and squalene monooxygenase), and cholesterol exporters (ATP-binding cassette transporters ABCA1 and ABCG1). We explore which E3 ligases are involved, and identify areas deserving of further research.
Collapse
Affiliation(s)
- Laura J Sharpe
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, NSW 2052, Australia
| | - Emma C L Cook
- Department of Medical Biochemistry, Academic Medical Center, University of Amsterdam, Meibergdreef 15, 1105AZ Amsterdam, The Netherlands
| | - Noam Zelcer
- Department of Medical Biochemistry, Academic Medical Center, University of Amsterdam, Meibergdreef 15, 1105AZ Amsterdam, The Netherlands.
| | - Andrew J Brown
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, NSW 2052, Australia.
| |
Collapse
|