1
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Wei X, Lu Y, Lin LL, Zhang C, Chen X, Wang S, Wu SA, Li ZJ, Quan Y, Sun S, Qi L. Proteomic screens of SEL1L-HRD1 ER-associated degradation substrates reveal its role in glycosylphosphatidylinositol-anchored protein biogenesis. Nat Commun 2024; 15:659. [PMID: 38253565 PMCID: PMC10803770 DOI: 10.1038/s41467-024-44948-2] [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: 06/15/2023] [Accepted: 01/08/2024] [Indexed: 01/24/2024] Open
Abstract
Endoplasmic reticulum-associated degradation (ERAD) plays indispensable roles in many physiological processes; however, the nature of endogenous substrates remains largely elusive. Here we report a proteomics strategy based on the intrinsic property of the SEL1L-HRD1 ERAD complex to identify endogenous ERAD substrates both in vitro and in vivo. Following stringent filtering using a machine learning algorithm, over 100 high-confidence potential substrates are identified in human HEK293T and mouse brown adipose tissue, among which ~88% are cell type-specific. One of the top shared hits is the catalytic subunit of the glycosylphosphatidylinositol (GPI)-transamidase complex, PIGK. Indeed, SEL1L-HRD1 ERAD attenuates the biogenesis of GPI-anchored proteins by specifically targeting PIGK for proteasomal degradation. Lastly, several PIGK disease variants in inherited GPI deficiency disorders are also SEL1L-HRD1 ERAD substrates. This study provides a platform and resources for future effort to identify proteome-wide endogenous substrates in vivo, and implicates SEL1L-HRD1 ERAD in many cellular processes including the biogenesis of GPI-anchored proteins.
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Affiliation(s)
- Xiaoqiong Wei
- Department of Molecular Physiology and Biological Physics, University of Virginia, School of Medicine, Charlottesville, VA, 22903, USA
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, 48105, USA
| | - You Lu
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, 48105, USA
- Life Sciences Institute and Department of Cell & Developmental Biology, University of Michigan Medical School, Ann Arbor, MI, 48109, USA
| | - Liangguang Leo Lin
- Department of Molecular Physiology and Biological Physics, University of Virginia, School of Medicine, Charlottesville, VA, 22903, USA
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, 48105, USA
| | - Chengxin Zhang
- Department of Computational Medicine and Bioinformatics, University of Michigan Medical School, Ann Arbor, MI, 48105, USA
| | - Xinxin Chen
- Department of Molecular Physiology and Biological Physics, University of Virginia, School of Medicine, Charlottesville, VA, 22903, USA
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, 48105, USA
| | - Siwen Wang
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, 48105, USA
| | - Shuangcheng Alivia Wu
- Department of Molecular Physiology and Biological Physics, University of Virginia, School of Medicine, Charlottesville, VA, 22903, USA
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, 48105, USA
| | - Zexin Jason Li
- Department of Molecular Physiology and Biological Physics, University of Virginia, School of Medicine, Charlottesville, VA, 22903, USA
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI, 48105, USA
| | - Yujun Quan
- Department of Molecular Physiology and Biological Physics, University of Virginia, School of Medicine, Charlottesville, VA, 22903, USA
| | - Shengyi Sun
- Department of Pharmacology, University of Virginia, School of Medicine, Charlottesville, VA, 22903, USA
| | - Ling Qi
- Department of Molecular Physiology and Biological Physics, University of Virginia, School of Medicine, Charlottesville, VA, 22903, USA.
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, 48105, USA.
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2
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Lee DM, Kim IY, Lee HJ, Seo MJ, Cho MY, Lee HI, Yoon G, Ji JH, Park SS, Jeong SY, Choi EK, Choi YH, Yun CO, Yeo M, Kim E, Choi KS. Akt enhances the vulnerability of cancer cells to VCP/p97 inhibition-mediated paraptosis. Cell Death Dis 2024; 15:48. [PMID: 38218922 PMCID: PMC10787777 DOI: 10.1038/s41419-024-06434-x] [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: 06/20/2023] [Revised: 12/19/2023] [Accepted: 01/04/2024] [Indexed: 01/15/2024]
Abstract
Valosin-containing protein (VCP)/p97, an AAA+ ATPase critical for maintaining proteostasis, emerges as a promising target for cancer therapy. This study reveals that targeting VCP selectively eliminates breast cancer cells while sparing non-transformed cells by inducing paraptosis, a non-apoptotic cell death mechanism characterized by endoplasmic reticulum and mitochondria dilation. Intriguingly, oncogenic HRas sensitizes non-transformed cells to VCP inhibition-mediated paraptosis. The susceptibility of cancer cells to VCP inhibition is attributed to the non-attenuation and recovery of protein synthesis under proteotoxic stress. Mechanistically, mTORC2/Akt activation and eIF3d-dependent translation contribute to translational rebound and amplification of proteotoxic stress. Furthermore, the ATF4/DDIT4 axis augments VCP inhibition-mediated paraptosis by activating Akt. Given that hyperactive Akt counteracts chemotherapeutic-induced apoptosis, VCP inhibition presents a promising therapeutic avenue to exploit Akt-associated vulnerabilities in cancer cells by triggering paraptosis while safeguarding normal cells.
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Affiliation(s)
- Dong Min Lee
- Department of Biochemistry and Molecular Biology, Ajou University School of Medicine, Suwon, Republic of Korea
- Department of Biomedical Sciences, Ajou University Graduate School of Medicine, Suwon, Republic of Korea
| | - In Young Kim
- Department of Biochemistry and Molecular Biology, Ajou University School of Medicine, Suwon, Republic of Korea
- Department of Biomedical Sciences, Ajou University Graduate School of Medicine, Suwon, Republic of Korea
| | - Hong Jae Lee
- Department of Biochemistry and Molecular Biology, Ajou University School of Medicine, Suwon, Republic of Korea
- Department of Biomedical Sciences, Ajou University Graduate School of Medicine, Suwon, Republic of Korea
| | - Min Ji Seo
- Department of Biochemistry and Molecular Biology, Ajou University School of Medicine, Suwon, Republic of Korea
- Department of Biomedical Sciences, Ajou University Graduate School of Medicine, Suwon, Republic of Korea
| | - Mi-Young Cho
- Department of Biochemistry and Molecular Biology, Ajou University School of Medicine, Suwon, Republic of Korea
- Department of Biomedical Sciences, Ajou University Graduate School of Medicine, Suwon, Republic of Korea
| | - Hae In Lee
- Department of Biochemistry and Molecular Biology, Ajou University School of Medicine, Suwon, Republic of Korea
- Department of Biomedical Sciences, Ajou University Graduate School of Medicine, Suwon, Republic of Korea
| | - Gyesoon Yoon
- Department of Biochemistry and Molecular Biology, Ajou University School of Medicine, Suwon, Republic of Korea
- Department of Biomedical Sciences, Ajou University Graduate School of Medicine, Suwon, Republic of Korea
| | - Jae-Hoon Ji
- Department of Biochemistry and Structural Biology, University of Texas Health at San Antonio, San Antonio, TX, USA
- Greehey Children's Cancer Research Institute, University of Texas Health at San Antonio, San Antonio, TX, USA
| | - Seok Soon Park
- Asan Institute for Life Sciences, Department of Convergence Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Seong-Yun Jeong
- Asan Institute for Life Sciences, Department of Convergence Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Eun Kyung Choi
- Asan Institute for Life Sciences, Department of Convergence Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Yong Hyeon Choi
- Department of Bioengineering, College of Engineering, Hanyang University, Seoul, Korea
| | - Chae-Ok Yun
- Department of Bioengineering, College of Engineering, Hanyang University, Seoul, Korea
| | - Mirae Yeo
- Department of Biological Sciences, Ulsan National Institute Science and Technology, Ulsan, South Korea
| | - Eunhee Kim
- Department of Biological Sciences, Ulsan National Institute Science and Technology, Ulsan, South Korea.
| | - Kyeong Sook Choi
- Department of Biochemistry and Molecular Biology, Ajou University School of Medicine, Suwon, Republic of Korea.
- Department of Biomedical Sciences, Ajou University Graduate School of Medicine, Suwon, Republic of Korea.
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3
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Kawan M, Körner M, Schlosser A, Buchberger A. p97/VCP Promotes the Recycling of Endocytic Cargo. Mol Biol Cell 2023; 34:ar126. [PMID: 37756124 PMCID: PMC10848945 DOI: 10.1091/mbc.e23-06-0237] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Revised: 09/11/2023] [Accepted: 09/20/2023] [Indexed: 09/29/2023] Open
Abstract
The endocytic pathway is of central importance for eukaryotic cells, as it enables uptake of extracellular materials, membrane protein quality control and recycling, as well as modulation of receptor signaling. While the ATPase p97 (VCP, Cdc48) has been found to be involved in the fusion of early endosomes and endolysosomal degradation, its role in endocytic trafficking is still incompletely characterized. Here, we identify myoferlin (MYOF), a ferlin family member with functions in membrane trafficking and repair, as a hitherto unknown p97 interactor. The interaction of MYOF with p97 depends on the cofactor PLAA previously linked to endosomal sorting. Besides PLAA, shared interactors of p97 and MYOF comprise several proteins involved in endosomal recycling pathways, including Rab11, Rab14, and the transferrin receptor CD71. Accordingly, a fraction of p97 and PLAA localizes to MYOF-, Rab11-, and Rab14-positive endosomal compartments. Pharmacological inhibition of p97 delays transferrin recycling, indicating that p97 promotes not only the lysosomal degradation, but also the recycling of endocytic cargo.
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Affiliation(s)
- Mona Kawan
- Chair of Biochemistry I, University of Würzburg, Biocenter, Am Hubland, 97074 Würzburg, Germany
| | - Maria Körner
- Chair of Biochemistry I, University of Würzburg, Biocenter, Am Hubland, 97074 Würzburg, Germany
| | - Andreas Schlosser
- Rudolf Virchow Center for Integrative and Translational Bioimaging, University of Würzburg, Josef-Schneider-Straße 2, 97080 Würzburg, Germany
| | - Alexander Buchberger
- Chair of Biochemistry I, University of Würzburg, Biocenter, Am Hubland, 97074 Würzburg, Germany
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4
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Miura K, Katsuki R, Yoshida S, Ohta R, Tamura T. Identification of EGF Receptor and Thrombospondin-1 as Endogenous Targets of ER-Associated Degradation Enhancer EDEM1 in HeLa Cells. Int J Mol Sci 2023; 24:12171. [PMID: 37569550 PMCID: PMC10418772 DOI: 10.3390/ijms241512171] [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: 06/08/2023] [Revised: 07/26/2023] [Accepted: 07/27/2023] [Indexed: 08/13/2023] Open
Abstract
Secretory and membrane proteins are vital for cell activities, including intra- and intercellular communication. Therefore, protein quality control in the endoplasmic reticulum (ER) is an essential and crucial process for eukaryotic cells. Endoplasmic reticulum-associated degradation (ERAD) targets misfolded proteins during the protein maturation process in the ER and leads to their disposal. This process maintains the ER productive function and prevents misfolded protein stress (i.e., ER stress). The ERAD-stimulating factor ER degradation-enhancing α mannosidase-like 1 protein (EDEM1) acts on misfolded proteins to accelerate ERAD, thereby maintaining the productivity of the ER. However, the detail mechanism underlying the function of EDEM1 in ERAD is not completely understood due to a lack of established physiological substrate proteins. In this study, we attempted to identify substrate proteins for EDEM1 using siRNA. The matrix component thrombospondin-1 (TSP1) and epidermal growth factor receptor (EGFR) were identified as candidate targets of EDEM1. Their protein maturation status and cellular localization were markedly affected by knockdown of EDEM1. We also showed that EDEM1 physically associates with EGFR and enhances EGFR degradation via ERAD. Our data highlight the physiological role of EDEM1 in maintaining specific target proteins and provide a potential approach to the regulation of expression of clinically important proteins.
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Affiliation(s)
- Kohta Miura
- Department of Life Science, Graduate School of Engineering Science, Akita University, Akita 010-8502, Japan
| | - Riko Katsuki
- Department of Life Science, Graduate School of Engineering Science, Akita University, Akita 010-8502, Japan
| | - Shusei Yoshida
- Department of Life Science, Faculty of Engineering Science, Akita University, Akita 010-8502, Japan
| | - Ren Ohta
- Department of Life Science, Graduate School of Engineering Science, Akita University, Akita 010-8502, Japan
| | - Taku Tamura
- Department of Life Science, Graduate School of Engineering Science, Akita University, Akita 010-8502, Japan
- Department of Life Science, Faculty of Engineering Science, Akita University, Akita 010-8502, Japan
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5
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Zhang X, Young C, Liao XH, Refetoff S, Torres M, Tomer Y, Stefan-Lifshitz M, Zhang H, Larkin D, Fang D, Qi L, Arvan P. Perturbation of endoplasmic reticulum proteostasis triggers tissue injury in the thyroid gland. JCI Insight 2023; 8:e169937. [PMID: 37345654 PMCID: PMC10371246 DOI: 10.1172/jci.insight.169937] [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: 02/21/2023] [Accepted: 05/09/2023] [Indexed: 06/23/2023] Open
Abstract
Defects in endoplasmic reticulum (ER) proteostasis have been linked to diseases in multiple organ systems. Here we examined the impact of perturbation of ER proteostasis in mice bearing thyrocyte-specific knockout of either HRD1 (to disable ER-associated protein degradation [ERAD]) or ATG7 (to disable autophagy) in the absence or presence of heterozygous expression of misfolded mutant thyroglobulin (the most highly expressed thyroid gene product, synthesized in the ER). Misfolding-inducing thyroglobulin mutations are common in humans but are said to yield only autosomal-recessive disease - perhaps because misfolded thyroglobulin protein might undergo disposal by ERAD or ER macroautophagy. We find that as single defects, neither ERAD, nor autophagy, nor heterozygous thyroglobulin misfolding altered circulating thyroxine levels, and neither defective ERAD nor defective autophagy caused any gross morphological change in an otherwise WT thyroid gland. However, heterozygous expression of misfolded thyroglobulin itself triggered significant ER stress and individual thyrocyte death while maintaining integrity of the surrounding thyroid epithelium. In this context, deficiency of ERAD (but not autophagy) resulted in patchy whole-follicle death with follicular collapse and degeneration, accompanied by infiltration of bone marrow-derived macrophages. Perturbation of thyrocyte ER proteostasis is thus a risk factor for both cell death and follicular demise.
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Affiliation(s)
- Xiaohan Zhang
- Division of Metabolism, Endocrinology & Diabetes and
| | - Crystal Young
- Division of Metabolism, Endocrinology & Diabetes and
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, Michigan, USA
| | | | - Samuel Refetoff
- Department of Medicine
- Department of Pediatrics, and Committee on Genetics, Genomics, and Systems Biology, The University of Chicago, Chicago, Illinois, USA
| | - Mauricio Torres
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, Michigan, USA
| | - Yaron Tomer
- Department of Medicine, Fleischer Institute for Diabetes and Metabolism, Albert Einstein College of Medicine, New York, New York, USA
| | - Mihaela Stefan-Lifshitz
- Department of Medicine, Fleischer Institute for Diabetes and Metabolism, Albert Einstein College of Medicine, New York, New York, USA
| | - Hao Zhang
- Division of Metabolism, Endocrinology & Diabetes and
| | - Dennis Larkin
- Division of Metabolism, Endocrinology & Diabetes and
| | - Deyu Fang
- Department of Pathology, Feinberg School of Medicine, Northwestern Medicine, Chicago, Illinois, USA
| | - Ling Qi
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, Michigan, USA
| | - Peter Arvan
- Division of Metabolism, Endocrinology & Diabetes and
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, Michigan, USA
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6
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Qian K, Tol MJ, Wu J, Uchiyama LF, Xiao X, Cui L, Bedard AH, Weston TA, Rajendran PS, Vergnes L, Shimanaka Y, Yin Y, Jami-Alahmadi Y, Cohn W, Bajar BT, Lin CH, Jin B, DeNardo LA, Black DL, Whitelegge JP, Wohlschlegel JA, Reue K, Shivkumar K, Chen FJ, Young SG, Li P, Tontonoz P. CLSTN3β enforces adipocyte multilocularity to facilitate lipid utilization. Nature 2023; 613:160-168. [PMID: 36477540 PMCID: PMC9995219 DOI: 10.1038/s41586-022-05507-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Accepted: 11/01/2022] [Indexed: 12/12/2022]
Abstract
Multilocular adipocytes are a hallmark of thermogenic adipose tissue1,2, but the factors that enforce this cellular phenotype are largely unknown. Here, we show that an adipocyte-selective product of the Clstn3 locus (CLSTN3β) present in only placental mammals facilitates the efficient use of stored triglyceride by limiting lipid droplet (LD) expansion. CLSTN3β is an integral endoplasmic reticulum (ER) membrane protein that localizes to ER-LD contact sites through a conserved hairpin-like domain. Mice lacking CLSTN3β have abnormal LD morphology and altered substrate use in brown adipose tissue, and are more susceptible to cold-induced hypothermia despite having no defect in adrenergic signalling. Conversely, forced expression of CLSTN3β is sufficient to enforce a multilocular LD phenotype in cultured cells and adipose tissue. CLSTN3β associates with cell death-inducing DFFA-like effector proteins and impairs their ability to transfer lipid between LDs, thereby restricting LD fusion and expansion. Functionally, increased LD surface area in CLSTN3β-expressing adipocytes promotes engagement of the lipolytic machinery and facilitates fatty acid oxidation. In human fat, CLSTN3B is a selective marker of multilocular adipocytes. These findings define a molecular mechanism that regulates LD form and function to facilitate lipid utilization in thermogenic adipocytes.
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Affiliation(s)
- Kevin Qian
- Department of Pathology and Laboratory Medicine, University of California, Los Angeles, Los Angeles, CA, USA
- Department of Biological Chemistry, University of California, Los Angeles, Los Angeles, CA, USA
- Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA, USA
| | - Marcus J Tol
- Department of Pathology and Laboratory Medicine, University of California, Los Angeles, Los Angeles, CA, USA
- Department of Biological Chemistry, University of California, Los Angeles, Los Angeles, CA, USA
- Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA, USA
| | - Jin Wu
- Institute of Metabolism and Integrative Biology, Fudan University, Shanghai, China
| | - Lauren F Uchiyama
- Department of Pathology and Laboratory Medicine, University of California, Los Angeles, Los Angeles, CA, USA
- Department of Biological Chemistry, University of California, Los Angeles, Los Angeles, CA, USA
- Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA, USA
| | - Xu Xiao
- Department of Pathology and Laboratory Medicine, University of California, Los Angeles, Los Angeles, CA, USA
- Department of Biological Chemistry, University of California, Los Angeles, Los Angeles, CA, USA
- Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA, USA
| | - Liujuan Cui
- Department of Pathology and Laboratory Medicine, University of California, Los Angeles, Los Angeles, CA, USA
- Department of Biological Chemistry, University of California, Los Angeles, Los Angeles, CA, USA
- Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA, USA
| | - Alexander H Bedard
- Department of Pathology and Laboratory Medicine, University of California, Los Angeles, Los Angeles, CA, USA
- Department of Biological Chemistry, University of California, Los Angeles, Los Angeles, CA, USA
- Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA, USA
| | - Thomas A Weston
- Department of Medicine, Division of Cardiology, University of California, Los Angeles, Los Angeles, CA, USA
- Department of Human Genetics, University of California, Los Angeles, Los Angeles, CA, USA
| | - Pradeep S Rajendran
- Cardiac Arrhythmia Center and Neurocardiology Research Program of Excellence, University of California, Los Angeles, Los Angeles, CA, USA
- Department of Medicine, Massachusetts General Hospital, Boston, MA, USA
| | - Laurent Vergnes
- Department of Human Genetics, University of California, Los Angeles, Los Angeles, CA, USA
| | - Yuta Shimanaka
- Department of Pathology and Laboratory Medicine, University of California, Los Angeles, Los Angeles, CA, USA
- Department of Biological Chemistry, University of California, Los Angeles, Los Angeles, CA, USA
- Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA, USA
| | - Yesheng Yin
- Institute of Metabolism and Integrative Biology, Fudan University, Shanghai, China
| | - Yasaman Jami-Alahmadi
- Department of Biological Chemistry, University of California, Los Angeles, Los Angeles, CA, USA
| | - Whitaker Cohn
- Pasarow Mass Spectrometry Laboratory, Semel Institute for Neuroscience and Human Behavior, University of California, Los Angeles, Los Angeles, CA, USA
| | - Bryce T Bajar
- Department of Biological Chemistry, University of California, Los Angeles, Los Angeles, CA, USA
| | - Chia-Ho Lin
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA, USA
| | - Benita Jin
- Department of Physiology, University of California, Los Angeles, Los Angeles, CA, USA
| | - Laura A DeNardo
- Department of Physiology, University of California, Los Angeles, Los Angeles, CA, USA
| | - Douglas L Black
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA, USA
| | - Julian P Whitelegge
- Pasarow Mass Spectrometry Laboratory, Semel Institute for Neuroscience and Human Behavior, University of California, Los Angeles, Los Angeles, CA, USA
| | - James A Wohlschlegel
- Department of Biological Chemistry, University of California, Los Angeles, Los Angeles, CA, USA
| | - Karen Reue
- Department of Human Genetics, University of California, Los Angeles, Los Angeles, CA, USA
| | - Kalyanam Shivkumar
- Cardiac Arrhythmia Center and Neurocardiology Research Program of Excellence, University of California, Los Angeles, Los Angeles, CA, USA
| | - Feng-Jung Chen
- Institute of Metabolism and Integrative Biology, Fudan University, Shanghai, China
| | - Stephen G Young
- Department of Medicine, Division of Cardiology, University of California, Los Angeles, Los Angeles, CA, USA
- Department of Human Genetics, University of California, Los Angeles, Los Angeles, CA, USA
| | - Peng Li
- Institute of Metabolism and Integrative Biology, Fudan University, Shanghai, China
- School of Life Sciences, Tsinghua University, Beijing, China
| | - Peter Tontonoz
- Department of Pathology and Laboratory Medicine, University of California, Los Angeles, Los Angeles, CA, USA.
- Department of Biological Chemistry, University of California, Los Angeles, Los Angeles, CA, USA.
- Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA, USA.
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7
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Ruan J, Liang D, Yan W, Zhong Y, Talley DC, Rai G, Tao D, LeClair CA, Simeonov A, Zhang Y, Chen F, Quinney NL, Boyles SE, Cholon DM, Gentzsch M, Henderson MJ, Xue F, Fang S. A small-molecule inhibitor and degrader of the RNF5 ubiquitin ligase. Mol Biol Cell 2022; 33:ar120. [PMID: 36074076 PMCID: PMC9634977 DOI: 10.1091/mbc.e22-06-0233] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
RNF5 E3 ubiquitin ligase has multiple biological roles and has been linked to the development of severe diseases such as cystic fibrosis, acute myeloid leukemia, and certain viral infections, emphasizing the importance of discovering small-molecule RNF5 modulators for research and drug development. The present study describes the synthesis of a new benzo[b]thiophene derivative, FX12, that acts as a selective small-molecule inhibitor and degrader of RNF5. We initially identified the previously reported STAT3 inhibitor, Stattic, as an inhibitor of dislocation of misfolded proteins from the endoplasmic reticulum (ER) lumen to the cytosol in ER-associated degradation. A concise structure-activity relationship campaign (SAR) around the Stattic chemotype led to the synthesis of FX12, which has diminished activity in inhibition of STAT3 activation and retains dislocation inhibitory activity. FX12 binds to RNF5 and inhibits its E3 activity in vitro as well as promoting proteasomal degradation of RNF5 in cells. RNF5 as a molecular target for FX12 was supported by the facts that FX12 requires RNF5 to inhibit dislocation and negatively regulates RNF5 function. Thus, this study developed a small-molecule inhibitor and degrader of the RNF5 ubiquitin ligase, providing a chemical biology tool for RNF5 research and therapeutic development.
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Affiliation(s)
- Jingjing Ruan
- Center for Biomedical Engineering and Technology, Department of Physiology, Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201,First Affiliated Hospital and
| | - Dongdong Liang
- University of Maryland School of Pharmacy, Baltimore, MD 21201
| | - Wenjing Yan
- Center for Biomedical Engineering and Technology, Department of Physiology, Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201
| | - Yongwang Zhong
- Center for Biomedical Engineering and Technology, Department of Physiology, Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201
| | - Daniel C. Talley
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD 20850
| | - Ganesha Rai
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD 20850
| | - Dingyin Tao
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD 20850
| | - Christopher A. LeClair
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD 20850
| | - Anton Simeonov
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD 20850
| | - Yinghua Zhang
- Center for Innovative Biomedical Resources, Biosensor Core, University of Maryland School of Medicine, Baltimore, MD 21201
| | - Feihu Chen
- School of Pharmacy, Anhui Medical University, Hefei, Anhui 230032, China
| | | | | | | | - Martina Gentzsch
- Marsico Lung Institute and Cystic Fibrosis Research Center,Department of Pediatric Pulmonology, and,Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Mark J. Henderson
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD 20850,*Address corespondence to: Shengyun Fang (lead contact) (); Mark J. Henderson (); Fengtian Xue ()
| | - Fengtian Xue
- University of Maryland School of Pharmacy, Baltimore, MD 21201,*Address corespondence to: Shengyun Fang (lead contact) (); Mark J. Henderson (); Fengtian Xue ()
| | - Shengyun Fang
- Center for Biomedical Engineering and Technology, Department of Physiology, Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201,*Address corespondence to: Shengyun Fang (lead contact) (); Mark J. Henderson (); Fengtian Xue ()
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8
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Xu X, Arunagiri A, Haataja L, Alam M, Ji S, Qi L, Tsai B, Liu M, Arvan P. Proteasomal degradation of wild-type proinsulin in pancreatic beta cells. J Biol Chem 2022; 298:102406. [PMID: 35988641 PMCID: PMC9486123 DOI: 10.1016/j.jbc.2022.102406] [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: 05/18/2022] [Revised: 07/25/2022] [Accepted: 07/26/2022] [Indexed: 11/22/2022] Open
Abstract
Preproinsulin entry into the endoplasmic reticulum yields proinsulin, and its subsequent delivery to the distal secretory pathway leads to processing, storage, and secretion of mature insulin. Multiple groups have reported that treatment of pancreatic beta cell lines, rodent pancreatic islets, or human islets with proteasome inhibitors leads to diminished proinsulin and insulin protein levels, diminished glucose-stimulated insulin secretion, and changes in beta-cell gene expression that ultimately lead to beta-cell death. However, these studies have mostly examined treatment times far beyond that needed to achieve acute proteasomal inhibition. Here, we report that although proteasomal inhibition immediately downregulates new proinsulin biosynthesis, it nevertheless acutely increases beta-cell proinsulin levels in pancreatic beta cell lines, rodent pancreatic islets, and human islets, indicating rescue of a pool of recently synthesized WT INS gene product that would otherwise be routed to proteasomal disposal. Our pharmacological evidence suggests that this disposal most likely reflects ongoing endoplasmic reticulum–associated protein degradation. However, we found that within 60 min after proteasomal inhibition, intracellular proinsulin levels begin to fall in conjunction with increased phosphorylation of eukaryotic initiation factor 2 alpha, which can be inhibited by blocking the general control nonderepressible 2 kinase. Together, these data demonstrate that a meaningful subfraction of newly synthesized INS gene product undergoes rapid proteasomal disposal. We propose that free amino acids derived from proteasomal proteolysis may potentially participate in suppressing general control nonderepressible 2 kinase activity to maintain ongoing proinsulin biosynthesis.
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Affiliation(s)
- Xiaoxi Xu
- The Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical Center, Ann Arbor, MI 48105; Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China 300052
| | - Anoop Arunagiri
- The Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical Center, Ann Arbor, MI 48105
| | - Leena Haataja
- The Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical Center, Ann Arbor, MI 48105
| | - Maroof Alam
- The Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical Center, Ann Arbor, MI 48105
| | - Shuhui Ji
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China 300052
| | - Ling Qi
- Departments of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48109
| | - Billy Tsai
- Departments of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI 48109
| | - Ming Liu
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China 300052.
| | - Peter Arvan
- The Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical Center, Ann Arbor, MI 48105.
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9
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Krastev DB, Li S, Sun Y, Wicks AJ, Hoslett G, Weekes D, Badder LM, Knight EG, Marlow R, Pardo MC, Yu L, Talele TT, Bartek J, Choudhary JS, Pommier Y, Pettitt SJ, Tutt ANJ, Ramadan K, Lord CJ. The ubiquitin-dependent ATPase p97 removes cytotoxic trapped PARP1 from chromatin. Nat Cell Biol 2022; 24:62-73. [PMID: 35013556 PMCID: PMC8760077 DOI: 10.1038/s41556-021-00807-6] [Citation(s) in RCA: 64] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Accepted: 11/03/2021] [Indexed: 12/12/2022]
Abstract
Poly (ADP-ribose) polymerase (PARP) inhibitors elicit antitumour activity in homologous recombination-defective cancers by trapping PARP1 in a chromatin-bound state. How cells process trapped PARP1 remains unclear. Using wild-type and a trapping-deficient PARP1 mutant combined with rapid immunoprecipitation mass spectrometry of endogenous proteins and Apex2 proximity labelling, we delineated mass spectrometry-based interactomes of trapped and non-trapped PARP1. These analyses identified an interaction between trapped PARP1 and the ubiquitin-regulated p97 ATPase/segregase. We found that following trapping, PARP1 is SUMOylated by PIAS4 and subsequently ubiquitylated by the SUMO-targeted E3 ubiquitin ligase RNF4, events that promote recruitment of p97 and removal of trapped PARP1 from chromatin. Small-molecule p97-complex inhibitors, including a metabolite of the clinically used drug disulfiram (CuET), prolonged PARP1 trapping and enhanced PARP inhibitor-induced cytotoxicity in homologous recombination-defective tumour cells and patient-derived tumour organoids. Together, these results suggest that p97 ATPase plays a key role in the processing of trapped PARP1 and the response of tumour cells to PARP inhibitors.
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Affiliation(s)
- Dragomir B Krastev
- The CRUK Gene Function Laboratory, London, UK
- Breast Cancer Now Toby Robins Research Centre, The Institute of Cancer Research, London, UK
| | - Shudong Li
- MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, UK
| | - Yilun Sun
- Developmental Therapeutics Branch, Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD, USA
| | - Andrew J Wicks
- The CRUK Gene Function Laboratory, London, UK
- Breast Cancer Now Toby Robins Research Centre, The Institute of Cancer Research, London, UK
| | - Gwendoline Hoslett
- MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, UK
| | - Daniel Weekes
- Breast Cancer Now Toby Robins Research Centre, The Institute of Cancer Research, London, UK
| | - Luned M Badder
- The Breast Cancer Now Research Unit, King's College London, London, UK
| | - Eleanor G Knight
- Breast Cancer Now Toby Robins Research Centre, The Institute of Cancer Research, London, UK
| | - Rebecca Marlow
- Breast Cancer Now Toby Robins Research Centre, The Institute of Cancer Research, London, UK
| | | | - Lu Yu
- Functional Proteomics Laboratory, The Institute of Cancer Research, London, UK
| | - Tanaji T Talele
- Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, St. John's University, Queens, NY, USA
| | - Jiri Bartek
- Danish Cancer Society Research Center, Copenhagen, Denmark
- Division of Genome Biology, Department of Medical Biochemistry and Biophysics, Science for Life Laboratory, Karolinska Institute, Stockholm, Sweden
| | - Jyoti S Choudhary
- Functional Proteomics Laboratory, The Institute of Cancer Research, London, UK
| | - Yves Pommier
- Developmental Therapeutics Branch, Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD, USA
| | - Stephen J Pettitt
- The CRUK Gene Function Laboratory, London, UK.
- Breast Cancer Now Toby Robins Research Centre, The Institute of Cancer Research, London, UK.
| | - Andrew N J Tutt
- Breast Cancer Now Toby Robins Research Centre, The Institute of Cancer Research, London, UK.
| | - Kristijan Ramadan
- MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, UK.
| | - Christopher J Lord
- The CRUK Gene Function Laboratory, London, UK.
- Breast Cancer Now Toby Robins Research Centre, The Institute of Cancer Research, London, UK.
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10
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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.
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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.
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11
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Shioi R, Karaki F, Yoshioka H, Noguchi-Yachide T, Ishikawa M, Dodo K, Hashimoto Y, Sodeoka M, Ohgane K. Image-based screen capturing misfolding status of Niemann-Pick type C1 identifies potential candidates for chaperone drugs. PLoS One 2020; 15:e0243746. [PMID: 33315900 PMCID: PMC7735562 DOI: 10.1371/journal.pone.0243746] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Accepted: 11/26/2020] [Indexed: 02/07/2023] Open
Abstract
Niemann-Pick disease type C is a rare, fatal neurodegenerative disorder characterized by massive intracellular accumulation of cholesterol. In most cases, loss-of-function mutations in the NPC1 gene that encodes lysosomal cholesterol transporter NPC1 are responsible for the disease, and more than half of the mutations are considered to interfere with the biogenesis or folding of the protein. We previously identified a series of oxysterol derivatives and phenanthridine-6-one derivatives as pharmacological chaperones, i.e., small molecules that can rescue folding-defective phenotypes of mutated NPC1, opening up an avenue to develop chaperone therapy for Niemann-Pick disease type C. Here, we present an improved image-based screen for NPC1 chaperones and we describe its application for drug-repurposing screening. We identified some azole antifungals, including itraconazole and posaconazole, and a kinase inhibitor, lapatinib, as probable pharmacological chaperones. A photo-crosslinking study confirmed direct binding of itraconazole to a representative folding-defective mutant protein, NPC1-I1061T. Competitive photo-crosslinking experiments suggested that oxysterol-based chaperones and itraconazole share the same or adjacent binding site(s), and the sensitivity of the crosslinking to P691S mutation in the sterol-sensing domain supports the hypothesis that their binding sites are located near this domain. Although the azoles were less effective in reducing cholesterol accumulation than the oxysterol-derived chaperones or an HDAC inhibitor, LBH-589, our findings should offer new starting points for medicinal chemistry efforts to develop better pharmacological chaperones for NPC1.
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Affiliation(s)
- Ryuta Shioi
- Institute for Quantitative Biosciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Fumika Karaki
- Institute for Quantitative Biosciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Hiromasa Yoshioka
- Institute for Quantitative Biosciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Tomomi Noguchi-Yachide
- Institute for Quantitative Biosciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Minoru Ishikawa
- Graduate School of Life Sciences, Tohoku University, Aoba-ku, Sendai, Japan
| | - Kosuke Dodo
- Synthetic Organic Chemistry Laboratory, RIKEN Cluster for Pioneering Research, Wako, Saitama, Japan
| | - Yuichi Hashimoto
- Institute for Quantitative Biosciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Mikiko Sodeoka
- Synthetic Organic Chemistry Laboratory, RIKEN Cluster for Pioneering Research, Wako, Saitama, Japan
| | - Kenji Ohgane
- Institute for Quantitative Biosciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
- Synthetic Organic Chemistry Laboratory, RIKEN Cluster for Pioneering Research, Wako, Saitama, Japan
- * E-mail:
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12
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Liu L, Dumbrepatil AB, Fleischhacker AS, Marsh ENG, Ragsdale SW. Heme oxygenase-2 is post-translationally regulated by heme occupancy in the catalytic site. J Biol Chem 2020; 295:17227-17240. [PMID: 33051205 PMCID: PMC7863905 DOI: 10.1074/jbc.ra120.014919] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2020] [Revised: 10/08/2020] [Indexed: 01/01/2023] Open
Abstract
Heme oxygenase-2 (HO2) and -1 (HO1) catalyze heme degradation to biliverdin, CO, and iron, forming an essential link in the heme metabolism network. Tight regulation of the cellular levels and catalytic activities of HO1 and HO2 is important for maintaining heme homeostasis. HO1 expression is transcriptionally regulated; however, HO2 expression is constitutive. How the cellular levels and activity of HO2 are regulated remains unclear. Here, we elucidate the mechanism of post-translational regulation of cellular HO2 levels by heme. We find that, under heme-deficient conditions, HO2 is destabilized and targeted for degradation, suggesting that heme plays a direct role in HO2 regulation. HO2 has three heme binding sites: one at its catalytic site and the others at its two heme regulatory motifs (HRMs). We report that, in contrast to other HRM-containing proteins, the cellular protein level and degradation rate of HO2 are independent of heme binding to the HRMs. Rather, under heme deficiency, loss of heme binding to the catalytic site destabilizes HO2. Consistently, an HO2 catalytic site variant that is unable to bind heme exhibits a constant low protein level and an enhanced protein degradation rate compared with the WT HO2. Finally, HO2 is degraded by the lysosome through chaperone-mediated autophagy, distinct from other HRM-containing proteins and HO1, which are degraded by the proteasome. These results reveal a novel aspect of HO2 regulation and deepen our understanding of HO2's role in maintaining heme homeostasis, paving the way for future investigation into HO2's pathophysiological role in heme deficiency response.
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Affiliation(s)
- Liu Liu
- Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan, USA
| | - Arti B Dumbrepatil
- Department of Chemistry, College of Literature, Science and Arts, University of Michigan, Ann Arbor, Michigan, USA
| | | | - E Neil G Marsh
- Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan, USA; Department of Chemistry, College of Literature, Science and Arts, University of Michigan, Ann Arbor, Michigan, USA
| | - Stephen W Ragsdale
- Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan, USA.
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13
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Buck TM, Zeng X, Cantrell PS, Cattley RT, Hasanbasri Z, Yates ME, Nguyen D, Yates NA, Brodsky JL. The Capture of a Disabled Proteasome Identifies Erg25 as a Substrate for Endoplasmic Reticulum Associated Degradation. Mol Cell Proteomics 2020; 19:1896-1909. [PMID: 32868373 DOI: 10.1074/mcp.ra120.002050] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Revised: 08/06/2020] [Indexed: 01/13/2023] Open
Abstract
Studies in the yeast Saccharomyces cerevisiae have helped define mechanisms underlying the activity of the ubiquitin-proteasome system (UPS), uncover the proteasome assembly pathway, and link the UPS to the maintenance of cellular homeostasis. However, the spectrum of UPS substrates is incompletely defined, even though multiple techniques-including MS-have been used. Therefore, we developed a substrate trapping proteomics workflow to identify previously unknown UPS substrates. We first generated a yeast strain with an epitope tagged proteasome subunit to which a proteasome inhibitor could be applied. Parallel experiments utilized inhibitor insensitive strains or strains lacking the tagged subunit. After affinity isolation, enriched proteins were resolved, in-gel digested, and analyzed by high resolution liquid chromatography-tandem MS. A total of 149 proteasome partners were identified, including all 33 proteasome subunits. When we next compared data between inhibitor sensitive and resistant cells, 27 proteasome partners were significantly enriched. Among these proteins were known UPS substrates and proteins that escort ubiquitinated substrates to the proteasome. We also detected Erg25 as a high-confidence partner. Erg25 is a methyl oxidase that converts dimethylzymosterol to zymosterol, a precursor of the plasma membrane sterol, ergosterol. Because Erg25 is a resident of the endoplasmic reticulum (ER) and had not previously been directly characterized as a UPS substrate, we asked whether Erg25 is a target of the ER associated degradation (ERAD) pathway, which most commonly mediates proteasome-dependent destruction of aberrant proteins. As anticipated, Erg25 was ubiquitinated and associated with stalled proteasomes. Further, Erg25 degradation depended on ERAD-associated ubiquitin ligases and was regulated by sterol synthesis. These data expand the cohort of lipid biosynthetic enzymes targeted for ERAD, highlight the role of the UPS in maintaining ER function, and provide a novel tool to uncover other UPS substrates via manipulations of our engineered strain.
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Affiliation(s)
- Teresa M Buck
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Xuemei Zeng
- Biomedical Mass Spectrometry Center, University of Pittsburgh Schools of the Health Sciences, Pittsburgh, Pennsylvania, USA
| | - Pamela S Cantrell
- Biomedical Mass Spectrometry Center, University of Pittsburgh Schools of the Health Sciences, Pittsburgh, Pennsylvania, USA
| | - Richard T Cattley
- Biomedical Mass Spectrometry Center, University of Pittsburgh Schools of the Health Sciences, Pittsburgh, Pennsylvania, USA
| | - Zikri Hasanbasri
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Megan E Yates
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Diep Nguyen
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Nathan A Yates
- Biomedical Mass Spectrometry Center, University of Pittsburgh Schools of the Health Sciences, Pittsburgh, Pennsylvania, USA; Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA; University of Pittsburgh Cancer Institute, Hillman Cancer Center, Pittsburgh, Pennsylvania, USA
| | - Jeffrey L Brodsky
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
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14
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van de Weijer ML, Krshnan L, Liberatori S, Guerrero EN, Robson-Tull J, Hahn L, Lebbink RJ, Wiertz EJHJ, Fischer R, Ebner D, Carvalho P. Quality Control of ER Membrane Proteins by the RNF185/Membralin Ubiquitin Ligase Complex. Mol Cell 2020; 79:768-781.e7. [PMID: 32738194 PMCID: PMC7482433 DOI: 10.1016/j.molcel.2020.07.009] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 05/06/2020] [Accepted: 07/07/2020] [Indexed: 12/16/2022]
Abstract
Misfolded proteins in the endoplasmic reticulum (ER) are degraded by ER-associated degradation (ERAD). Although ERAD components involved in degradation of luminal substrates are well characterized, much less is known about quality control of membrane proteins. Here, we analyzed the degradation pathways of two short-lived ER membrane model proteins in mammalian cells. Using a CRISPR-Cas9 genome-wide library screen, we identified an ERAD branch required for quality control of a subset of membrane proteins. Using biochemical and mass spectrometry approaches, we showed that this ERAD branch is defined by an ER membrane complex consisting of the ubiquitin ligase RNF185, the ubiquitin-like domain containing proteins TMUB1/2 and TMEM259/Membralin, a poorly characterized protein. This complex cooperates with cytosolic ubiquitin ligase UBE3C and p97 ATPase in degrading their membrane substrates. Our data reveal that ERAD branches have remarkable specificity for their membrane substrates, suggesting that multiple, perhaps combinatorial, determinants are involved in substrate selection. The RNF185 ubiquitin ligase, Membralin, and TMUB1/2 assemble into an ERAD complex RNF185/Membralin complex targets membrane proteins, including CYP51A1 and TMUB2 RNF185/Membralin and TEB4 ERAD complexes recognize distinct substrate features TEB4 ERAD complex recognizes substrates through their transmembrane domain
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Affiliation(s)
- Michael L van de Weijer
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Logesvaran Krshnan
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Sabrina Liberatori
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Elena Navarro Guerrero
- Nuffield Department of Medicine, Target Discovery Institute, University of Oxford, Oxford OX3 7FZ, UK
| | - Jacob Robson-Tull
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Lilli Hahn
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Robert Jan Lebbink
- Medical Microbiology, University Medical Center Utrecht, 3584 Utrecht, the Netherlands
| | - Emmanuel J H J Wiertz
- Medical Microbiology, University Medical Center Utrecht, 3584 Utrecht, the Netherlands
| | - Roman Fischer
- Nuffield Department of Medicine, Target Discovery Institute, University of Oxford, Oxford OX3 7FZ, UK
| | - Daniel Ebner
- Nuffield Department of Medicine, Target Discovery Institute, University of Oxford, Oxford OX3 7FZ, UK
| | - Pedro Carvalho
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK.
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15
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Fenech EJ, Lari F, Charles PD, Fischer R, Laétitia-Thézénas M, Bagola K, Paton AW, Paton JC, Gyrd-Hansen M, Kessler BM, Christianson JC. Interaction mapping of endoplasmic reticulum ubiquitin ligases identifies modulators of innate immune signalling. eLife 2020; 9:e57306. [PMID: 32614325 PMCID: PMC7332293 DOI: 10.7554/elife.57306] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Accepted: 06/11/2020] [Indexed: 12/25/2022] Open
Abstract
Ubiquitin ligases (E3s) embedded in the endoplasmic reticulum (ER) membrane regulate essential cellular activities including protein quality control, calcium flux, and sterol homeostasis. At least 25 different, transmembrane domain (TMD)-containing E3s are predicted to be ER-localised, but for most their organisation and cellular roles remain poorly defined. Using a comparative proteomic workflow, we mapped over 450 protein-protein interactions for 21 stably expressed, full-length E3s. Bioinformatic analysis linked ER-E3s and their interactors to multiple homeostatic, regulatory, and metabolic pathways. Among these were four membrane-embedded interactors of RNF26, a polytopic E3 whose abundance is auto-regulated by ubiquitin-proteasome dependent degradation. RNF26 co-assembles with TMEM43, ENDOD1, TMEM33 and TMED1 to form a complex capable of modulating innate immune signalling through the cGAS-STING pathway. This RNF26 complex represents a new modulatory axis of STING and innate immune signalling at the ER membrane. Collectively, these data reveal the broad scope of regulation and differential functionalities mediated by ER-E3s for both membrane-tethered and cytoplasmic processes.
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Affiliation(s)
- Emma J Fenech
- Ludwig Institute for Cancer Research, Nuffield Department of Medicine, University of OxfordOxfordUnited Kingdom
| | - Federica Lari
- Ludwig Institute for Cancer Research, Nuffield Department of Medicine, University of OxfordOxfordUnited Kingdom
| | - Philip D Charles
- TDI Mass Spectrometry Laboratory, Target Discovery Institute, University of OxfordOxfordUnited Kingdom
| | - Roman Fischer
- TDI Mass Spectrometry Laboratory, Target Discovery Institute, University of OxfordOxfordUnited Kingdom
| | - Marie Laétitia-Thézénas
- TDI Mass Spectrometry Laboratory, Target Discovery Institute, University of OxfordOxfordUnited Kingdom
| | - Katrin Bagola
- Ludwig Institute for Cancer Research, Nuffield Department of Medicine, University of OxfordOxfordUnited Kingdom
| | - Adrienne W Paton
- Research Centre for Infectious Diseases, Department of Molecular and Biomedical Science, University of AdelaideAdelaideAustralia
| | - James C Paton
- Research Centre for Infectious Diseases, Department of Molecular and Biomedical Science, University of AdelaideAdelaideAustralia
| | - Mads Gyrd-Hansen
- Ludwig Institute for Cancer Research, Nuffield Department of Medicine, University of OxfordOxfordUnited Kingdom
| | - Benedikt M Kessler
- TDI Mass Spectrometry Laboratory, Target Discovery Institute, University of OxfordOxfordUnited Kingdom
- Chinese Academy of Medical Sciences Oxford Institute, Nuffield Department of Medicine, University of OxfordOxfordUnited Kingdom
| | - John C Christianson
- Ludwig Institute for Cancer Research, Nuffield Department of Medicine, University of OxfordOxfordUnited Kingdom
- Nuffield Department of Orthopaedics, Rheumatology, and Musculoskeletal Sciences, University of Oxford, Botnar Research CentreOxfordUnited Kingdom
- Oxford Centre for Translational Myeloma Research, University of Oxford, Botnar Research CentreOxfordUnited Kingdom
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16
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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.
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17
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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.
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18
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Capell-Hattam IM, Sharpe LJ, Qian L, Hart-Smith G, Prabhu AV, Brown AJ. Twin enzymes, divergent control: The cholesterogenic enzymes DHCR14 and LBR are differentially regulated transcriptionally and post-translationally. J Biol Chem 2020; 295:2850-2865. [PMID: 31911440 PMCID: PMC7049974 DOI: 10.1074/jbc.ra119.011323] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Revised: 12/13/2019] [Indexed: 01/07/2023] Open
Abstract
Cholesterol synthesis is a tightly regulated process, both transcriptionally and post-translationally. Transcriptional control of cholesterol synthesis is relatively well-understood. However, of the ∼20 enzymes in cholesterol biosynthesis, post-translational regulation has only been examined for a small number. Three of the four sterol reductases in cholesterol production, 7-dehydrocholesterol reductase (DHCR7), 14-dehydrocholesterol reductase (DHCR14), and lamin-B receptor (LBR), share evolutionary ties with a high level of sequence homology and predicted structural homology. DHCR14 and LBR uniquely share the same Δ-14 reductase activity in cholesterol biosynthesis, yet little is known about their post-translational regulation. We have previously identified specific modes of post-translational control of DHCR7, but it is unknown whether these regulatory mechanisms are shared by DHCR14 and LBR. Using CHO-7 cells stably expressing epitope-tagged DHCR14 or LBR, we investigated the post-translational regulation of these enzymes. We found that DHCR14 and LBR undergo differential post-translational regulation, with DHCR14 being rapidly turned over, triggered by cholesterol and other sterol intermediates, whereas LBR remained stable. DHCR14 is degraded via the ubiquitin-proteasome system, and we identified several DHCR14 and DHCR7 putative interaction partners, including a number of E3 ligases that modulate DHCR14 levels. Interestingly, we found that gene expression across an array of human tissues showed a negative relationship between the C14-sterol reductases; one enzyme or the other tends to be predominantly expressed in each tissue. Overall, our findings indicate that whereas LBR tends to be the constitutively active C14-sterol reductase, DHCR14 levels are tunable, responding to the local cellular demands for cholesterol.
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Affiliation(s)
- Isabelle M Capell-Hattam
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Sydney, New South Wales 2052, Australia
| | - Laura J Sharpe
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Sydney, New South Wales 2052, Australia
| | - Lydia Qian
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Sydney, New South Wales 2052, Australia
| | - Gene Hart-Smith
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Sydney, New South Wales 2052, Australia; Department of Molecular Sciences, Macquarie University, Macquarie Park, New South Wales 2109, Australia
| | - Anika V Prabhu
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Sydney, New South Wales 2052, Australia
| | - Andrew J Brown
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Sydney, New South Wales 2052, Australia.
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19
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Sui X, Pan M, Li YM. Insights into the Design of p97-targeting Small Molecules from Structural Studies on p97 Functional Mechanism. Curr Med Chem 2020; 27:298-316. [PMID: 31584361 DOI: 10.2174/0929867326666191004162411] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Revised: 08/24/2019] [Accepted: 08/27/2019] [Indexed: 12/14/2022]
Abstract
p97, also known as valosin-containing protein or CDC48, is a member of the AAA+ protein family that is highly conserved in eukaryotes. It binds to various cofactors in the body to perform its protein-unfolding function and participates in DNA repair, degradation of subcellular membrane proteins, and protein quality control pathways, among other processes. Its malfunction can lead to many diseases, such as inclusion body myopathy, associated with Paget's disease of bone and/or frontotemporal dementia, amyotrophic lateral sclerosis disease, and others. In recent years, many small-molecule inhibitors have been deployed against p97, including bis (diethyldithiocarbamate)- copper and CB-5083, which entered the first phase of clinical tests but failed. One bottleneck in the design of p97 drugs is that its molecular mechanism remains unclear. This paper summarizes recent studies on the molecular mechanisms of p97, which may lead to insight into how the next generation of small molecules targeting p97 can be designed.
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Affiliation(s)
- Xin Sui
- Department of Chemistry, Tsinghua University, Beijing 100086, China
| | - Man Pan
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, Illinois 60637, United States
| | - Yi-Ming Li
- School of Food and Biological Engineering, Hefei University of Technology, Hefei, Anhui 230009, China
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20
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Abstract
p97 belongs to the functional diverse superfamily of AAA+ (ATPases Associated with diverse cellular Activities) ATPases and is characterized by an N-terminal regulatory domain and two stacked hexameric ATPase domains forming a central protein conducting channel. p97 is highly versatile and has key functions in maintaining protein homeostasis including protein quality control mechanisms like the ubiquitin proteasome system (UPS) and autophagy to disassemble polyubiquitylated proteins from chromatin, membranes, macromolecular protein complexes and aggregates which are either degraded by the proteasome or recycled. p97 can use energy derived from ATP hydrolysis to catalyze substrate unfolding and threading through its central channel. The function of p97 in a large variety of different cellular contexts is reflected by its simultaneous association with different cofactors, which are involved in substrate recognition and processing, thus leading to the formation of transient multi-protein complexes. Dysregulation in protein homeostasis and proteotoxic stress are often involved in the development of cancer and neurological diseases and targeting the UPS including p97 in cancer is a well-established pharmacological strategy. In this chapter we will describe structural and functional aspects of the p97 interactome in regulating diverse cellular processes and will discuss the role of p97 in targeted cancer therapy.
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21
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Sagimori I, Yoshioka H, Hashimoto Y, Ohgane K. Luciferase-based HMG-CoA reductase degradation assay for activity and selectivity profiling of oxy(lano)sterols. Bioorg Med Chem 2020; 28:115298. [PMID: 31902650 DOI: 10.1016/j.bmc.2019.115298] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 12/21/2019] [Accepted: 12/25/2019] [Indexed: 11/18/2022]
Abstract
HMG-CoA reductase (HMGCR) is the rate-limiting enzyme in the cholesterol biosynthetic pathway, and is the target of cholesterol-lowering drugs, statins. Previous studies have demonstrated that the enzyme activity is regulated by sterol-induced degradation in addition to transcriptional regulation through sterol-regulatory-element-binding proteins (SREBPs). While 25-hydroxycholesterol induces both HMGCR degradation and SREBP inhibition in a nonselective manner, lanosterol selectively induces HMGCR degradation. Here, to clarify the structural determinants of selectivity for the two activities, we established a luciferase-based assay monitoring HMGCR degradation and used it to profile the structure-activity/selectivity relationships of oxysterols and (oxy)lanosterols. We identified several sterols that selectively induce HMGCR degradation and one sterol, 25-hydroxycholest-4-en-3-one, that selectively inhibits the SREBP pathway. These results should be helpful in designing more potent and selective HMGCR degraders.
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Affiliation(s)
- Ikuya Sagimori
- Institute for Quantitative Biosciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan
| | - Hiromasa Yoshioka
- Institute for Quantitative Biosciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan
| | - Yuichi Hashimoto
- Institute for Quantitative Biosciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan
| | - Kenji Ohgane
- Institute for Quantitative Biosciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan.
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22
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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.
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23
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Llinàs-Arias P, Rosselló-Tortella M, López-Serra P, Pérez-Salvia M, Setién F, Marin S, Muñoz JP, Junza A, Capellades J, Calleja-Cervantes ME, Ferreira HJ, de Moura MC, Srbic M, Martínez-Cardús A, de la Torre C, Villanueva A, Cascante M, Yanes O, Zorzano A, Moutinho C, Esteller M. Epigenetic loss of the endoplasmic reticulum-associated degradation inhibitor SVIP induces cancer cell metabolic reprogramming. JCI Insight 2019; 5:125888. [PMID: 30843871 DOI: 10.1172/jci.insight.125888] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The endoplasmic reticulum (ER) of cancer cells needs to adapt to the enhanced proteotoxic stress associated with the accumulation of unfolded, misfolded and transformation-associated proteins. One way by which tumors thrive in the context of ER stress is by promoting ER-Associated Degradation (ERAD), although the mechanisms are poorly understood. Here, we show that the Small p97/VCP Interacting Protein (SVIP), an endogenous inhibitor of ERAD, undergoes DNA hypermethylation-associated silencing in tumorigenesis to achieve this goal. SVIP exhibits tumor suppressor features and its recovery is associated with increased ER stress and growth inhibition. Proteomic and metabolomic analyses show that cancer cells with epigenetic loss of SVIP are depleted in mitochondrial enzymes and oxidative respiration activity. This phenotype is reverted upon SVIP restoration. The dependence of SVIP hypermethylated cancer cells on aerobic glycolysis and glucose was also associated with sensitivity to an inhibitor of the glucose transporter GLUT1. This could be relevant to the management of tumors carrying SVIP epigenetic loss, because these occur in high-risk patients who manifest poor clinical outcomes. Overall, our study provides insights into how epigenetics helps deal with ER stress and how SVIP epigenetic loss in cancer may be amenable to therapies that target glucose transporters.
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Affiliation(s)
- Pere Llinàs-Arias
- Cancer Epigenetics Group, Cancer Epigenetics and Biology Program (PEBC), Bellvitge Biomedical Biomedical Research Institute (IDIBELL), Barcelona, Catalonia, Spain.,Centro de Investigacion Biomedica en Red Cancer (CIBERONC), Madrid, Spain
| | - Margalida Rosselló-Tortella
- Cancer Epigenetics Group, Cancer Epigenetics and Biology Program (PEBC), Bellvitge Biomedical Biomedical Research Institute (IDIBELL), Barcelona, Catalonia, Spain
| | - Paula López-Serra
- Cancer Epigenetics Group, Cancer Epigenetics and Biology Program (PEBC), Bellvitge Biomedical Biomedical Research Institute (IDIBELL), Barcelona, Catalonia, Spain
| | - Montserrat Pérez-Salvia
- Cancer Epigenetics Group, Cancer Epigenetics and Biology Program (PEBC), Bellvitge Biomedical Biomedical Research Institute (IDIBELL), Barcelona, Catalonia, Spain.,Centro de Investigacion Biomedica en Red Cancer (CIBERONC), Madrid, Spain
| | - Fernando Setién
- Cancer Epigenetics Group, Cancer Epigenetics and Biology Program (PEBC), Bellvitge Biomedical Biomedical Research Institute (IDIBELL), Barcelona, Catalonia, Spain
| | - Silvia Marin
- Department of Biochemistry and Molecular Biomedicine, Faculty of Biology, University of Barcelona, Barcelona, Spain.,Institute of Biomedicine of Universitat de Barcelona (IBUB), Barcelona, Spain.,CIBER of Liver and Digestive Diseases (CIBEREHD), Madrid, Spain
| | - Juan P Muñoz
- Department of Biochemistry and Molecular Biomedicine, Faculty of Biology, University of Barcelona, Barcelona, Spain.,Institute for Research in Biomedicine (IRB Barcelona), Barcelona Institute of Science and Technology, Barcelona, Spain.,CIBER of Diabetes and Associated Metabolic Diseases (CIBERDEM), Madrid, Spain
| | - Alexandra Junza
- CIBER of Diabetes and Associated Metabolic Diseases (CIBERDEM), Madrid, Spain.,Metabolomics Platform, IISPV, Department of Electronic Engineering (DEEEA), Universitat Rovira i Virgili, Tarragona, Catalonia, Spain
| | - Jordi Capellades
- CIBER of Diabetes and Associated Metabolic Diseases (CIBERDEM), Madrid, Spain.,Metabolomics Platform, IISPV, Department of Electronic Engineering (DEEEA), Universitat Rovira i Virgili, Tarragona, Catalonia, Spain
| | - María E Calleja-Cervantes
- Cancer Epigenetics Group, Cancer Epigenetics and Biology Program (PEBC), Bellvitge Biomedical Biomedical Research Institute (IDIBELL), Barcelona, Catalonia, Spain
| | - Humberto J Ferreira
- Cancer Epigenetics Group, Cancer Epigenetics and Biology Program (PEBC), Bellvitge Biomedical Biomedical Research Institute (IDIBELL), Barcelona, Catalonia, Spain
| | - Manuel Castro de Moura
- Cancer Epigenetics Group, Cancer Epigenetics and Biology Program (PEBC), Bellvitge Biomedical Biomedical Research Institute (IDIBELL), Barcelona, Catalonia, Spain
| | - Marina Srbic
- Cancer Epigenetics Group, Cancer Epigenetics and Biology Program (PEBC), Bellvitge Biomedical Biomedical Research Institute (IDIBELL), Barcelona, Catalonia, Spain
| | - Anna Martínez-Cardús
- Cancer Epigenetics Group, Cancer Epigenetics and Biology Program (PEBC), Bellvitge Biomedical Biomedical Research Institute (IDIBELL), Barcelona, Catalonia, Spain
| | - Carolina de la Torre
- Proteomics Unit, Bellvitge Biomedical Research Institute (IDIBELL), L'Hospitalet, Barcelona, Catalonia, Spain
| | - Alberto Villanueva
- Translational Research Laboratory, Catalan Institute of Oncology (ICO), Bellvitge Biomedical Research Institute (IDIBELL), L'Hospitalet, Barcelona, Catalonia, Spain
| | - Marta Cascante
- Department of Biochemistry and Molecular Biomedicine, Faculty of Biology, University of Barcelona, Barcelona, Spain.,Institute of Biomedicine of Universitat de Barcelona (IBUB), Barcelona, Spain.,CIBER of Liver and Digestive Diseases (CIBEREHD), Madrid, Spain
| | - Oscar Yanes
- CIBER of Diabetes and Associated Metabolic Diseases (CIBERDEM), Madrid, Spain.,Metabolomics Platform, IISPV, Department of Electronic Engineering (DEEEA), Universitat Rovira i Virgili, Tarragona, Catalonia, Spain
| | - Antonio Zorzano
- Department of Biochemistry and Molecular Biomedicine, Faculty of Biology, University of Barcelona, Barcelona, Spain.,Institute for Research in Biomedicine (IRB Barcelona), Barcelona Institute of Science and Technology, Barcelona, Spain.,CIBER of Diabetes and Associated Metabolic Diseases (CIBERDEM), Madrid, Spain
| | - Catia Moutinho
- Cancer Epigenetics Group, Cancer Epigenetics and Biology Program (PEBC), Bellvitge Biomedical Biomedical Research Institute (IDIBELL), Barcelona, Catalonia, Spain.,CNAG-CRG, Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology (BIST), Barcelona, Spain
| | - Manel Esteller
- Cancer Epigenetics Group, Cancer Epigenetics and Biology Program (PEBC), Bellvitge Biomedical Biomedical Research Institute (IDIBELL), Barcelona, Catalonia, Spain.,Centro de Investigacion Biomedica en Red Cancer (CIBERONC), Madrid, Spain.,Josep Carreras Leukaemia Research Institute (IJC), Badalona, Barcelona, Catalonia, Spain.,Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Catalonia, Spain.,Physiological Sciences Department, School of Medicine and Health Sciences, University of Barcelona, Catalonia, Spain
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24
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Sharpe LJ, Howe V, Scott NA, Luu W, Phan L, Berk JM, Hochstrasser M, Brown AJ. Cholesterol increases protein levels of the E3 ligase MARCH6 and thereby stimulates protein degradation. J Biol Chem 2018; 294:2436-2448. [PMID: 30545937 DOI: 10.1074/jbc.ra118.005069] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Revised: 12/06/2018] [Indexed: 12/12/2022] Open
Abstract
The E3 ligase membrane-associated ring-CH-type finger 6 (MARCH6) is a polytopic enzyme bound to the membranes of the endoplasmic reticulum. It controls levels of several known protein substrates, including a key enzyme in cholesterol synthesis, squalene monooxygenase. However, beyond its own autodegradation, little is known about how MARCH6 itself is regulated. Using CRISPR/Cas9 gene-editing, MARCH6 overexpression, and immunoblotting, we found here that cholesterol stabilizes MARCH6 protein endogenously and in HEK293 cells that stably express MARCH6. Conversely, MARCH6-deficient HEK293 and HeLa cells lost their ability to degrade squalene monooxygenase in a cholesterol-dependent manner. The ability of cholesterol to boost MARCH6 did not seem to involve a putative sterol-sensing domain in this E3 ligase, but was abolished when either membrane extraction by valosin-containing protein (VCP/p97) or proteasomal degradation was inhibited. Furthermore, cholesterol-mediated stabilization was absent in two MARCH6 mutants that are unable to degrade themselves, indicating that cholesterol stabilizes MARCH6 protein by preventing its autodegradation. Experiments with chemical chaperones suggested that this likely occurs through a conformational change in MARCH6 upon cholesterol addition. Moreover, cholesterol reduced the levels of at least three known MARCH6 substrates, indicating that cholesterol-mediated MARCH6 stabilization increases its activity. Our findings highlight an important new role for cholesterol in controlling levels of proteins, extending the known repertoire of cholesterol homeostasis players.
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Affiliation(s)
- Laura J Sharpe
- From the School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Sydney, New South Wales 2052, Australia and
| | - Vicky Howe
- From the School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Sydney, New South Wales 2052, Australia and
| | - Nicola A Scott
- From the School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Sydney, New South Wales 2052, Australia and
| | - Winnie Luu
- From the School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Sydney, New South Wales 2052, Australia and
| | - Lisa Phan
- From the School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Sydney, New South Wales 2052, Australia and
| | - Jason M Berk
- the Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520
| | - Mark Hochstrasser
- the Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520
| | - Andrew J Brown
- From the School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Sydney, New South Wales 2052, Australia and
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25
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Davis D, Kannan M, Wattenberg B. Orm/ORMDL proteins: Gate guardians and master regulators. Adv Biol Regul 2018; 70:3-18. [PMID: 30193828 DOI: 10.1016/j.jbior.2018.08.002] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Revised: 08/26/2018] [Accepted: 08/28/2018] [Indexed: 12/22/2022]
Abstract
Sphingolipids comprise a diverse family of lipids that perform multiple functions in both structure of cellular membranes and intra- and inter-cellular signaling. The diversity of this family is generated by an array of enzymes that produce individual classes and molecular species of family members and enzymes which catabolize those lipids for recycling pathways. However, all of these lipids begin their lives with a single step, the condensation of an amino acid, almost always serine, and a fatty acyl-CoA, almost always the 16-carbon, saturated fatty acid, palmitate. The enzyme complex that accomplishes this condensation is serine palmitoyltransferase (SPT), a membrane-bound component of the endoplasmic reticulum. This places SPT in the unique position of regulating the production of the entire sphingolipid pool. Understanding how SPT activity is regulated is currently a central focus in the field of sphingolipid biology. In this review we examine the regulation of SPT activity by a set of small, membrane-bound proteins of the endoplasmic reticulum, the Orms (in yeast) and ORMDLs (in vertebrates). We discuss what is known about how these proteins act as homeostatic regulators by monitoring cellular levels of sphingolipid, but also how the Orms/ORMDLs regulate SPT in response to other stimuli. Finally, we discuss the intriguing connection between one of the mammalian ORMDL isoforms, ORMDL3, and the pervasive pulmonary disease, asthma, in humans.
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Affiliation(s)
- Deanna Davis
- Department of Biochemistry and Molecular Biology, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Muthukumar Kannan
- Department of Biochemistry and Molecular Biology, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Binks Wattenberg
- Department of Biochemistry and Molecular Biology, Virginia Commonwealth University, Richmond, VA 23298, USA.
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