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Pan X, Mastrella S, Khamzaaliyeva M, Ashley DD. Exploring the connections between ER-based lipid metabolism and plasma membrane nanodomain signaling. THE NEW PHYTOLOGIST 2024; 243:48-57. [PMID: 38757654 DOI: 10.1111/nph.19815] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2024] [Accepted: 04/26/2024] [Indexed: 05/18/2024]
Abstract
Recent advancements in our understanding of cell membrane dynamics have shed light on the importance of plasma membrane (PM) nanodomains in plant cell signaling. Nevertheless, many aspects of membrane nanodomains, including their regulatory mechanisms and biological functions, remain enigmatic. To address this knowledge gap, our review article proposes a novel perspective wherein signaling pathways target endoplasmic reticulum (ER)-based lipid metabolism to exert control over the formation and function of membrane nanodomains. Subsequently, these nanodomains reciprocate by influencing the localization and activity of signaling molecules at the PM. We place a specific emphasis on ER-based enzymatic reactions, given the ER's central role in membrane lipid biosynthesis and its capacity to directly impact PM lipid composition, particularly with regard to saturation levels - an essential determinant of nanodomain properties. The interplay among cell signaling, glycerolipid metabolism, and PM nanodomain may create feedforward/feedback loops that fine-tune cellular responses to developmental and environmental cues.
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Affiliation(s)
- Xue Pan
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, ON, M1C 1A4, Canada
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, M5S 3G5, Canada
| | - Sophia Mastrella
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, ON, M1C 1A4, Canada
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, M5S 3G5, Canada
| | - Mohinur Khamzaaliyeva
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, ON, M1C 1A4, Canada
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, M5S 3G5, Canada
| | - Didier-Deschamps Ashley
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, ON, M1C 1A4, Canada
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Ramazanov BR, Parchure A, Di Martino R, Kumar A, Chung M, Kim Y, Griesbeck O, Schwartz MA, Luini A, von Blume J. Calcium flow at ER-TGN contact sites facilitates secretory cargo export. Mol Biol Cell 2024; 35:ar50. [PMID: 38294859 PMCID: PMC11064664 DOI: 10.1091/mbc.e23-03-0099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 01/19/2024] [Accepted: 01/24/2024] [Indexed: 02/01/2024] Open
Abstract
Ca2+ influx into the trans-Golgi Network (TGN) promotes secretory cargo sorting by the Ca2+-ATPase SPCA1 and the luminal Ca2+ binding protein Cab45. Cab45 oligomerizes upon local Ca2+ influx, and Cab45 oligomers sequester and separate soluble secretory cargo from the bulk flow of proteins in the TGN. However, how this Ca2+ flux into the lumen of the TGN is achieved remains mysterious, as the cytosol has a nanomolar steady-state Ca2+ concentration. The TGN forms membrane contact sites (MCS) with the Endoplasmic Reticulum (ER), allowing protein-mediated exchange of molecular species such as lipids. Here, we show that the TGN export of secretory proteins requires the integrity of ER-TGN MCS and inositol 3 phosphate receptor (IP3R)-dependent Ca2+ fluxes in the MCS, suggesting Ca2+ transfer between these organelles. Using an MCS-targeted Ca2+ FRET sensor module, we measure the Ca2+ flow in these sites in real time. These data show that ER-TGN MCS facilitates the Ca2+ transfer required for Ca2+-dependent cargo sorting and export from the TGN, thus solving a fundamental question in cell biology.
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Affiliation(s)
- Bulat R. Ramazanov
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510
| | - Anup Parchure
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510
| | - Rosaria Di Martino
- Institute of Biochemistry and Cell Biology, National Research Council, Naples 80131, Italy
| | - Abhishek Kumar
- Yale Cardiovascular Research Center, Yale University School of Medicine, New Haven, CT 06510
| | - Minhwan Chung
- Yale Cardiovascular Research Center, Yale University School of Medicine, New Haven, CT 06510
| | - Yeongho Kim
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510
| | - Oliver Griesbeck
- Max Planck Institute of Neurobiology, Martinsried 82152, Germany
| | - Martin A. Schwartz
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510
- Yale Cardiovascular Research Center, Yale University School of Medicine, New Haven, CT 06510
- Department of Biomedical Engineering, Yale University, New Haven, CT 06511
| | - Alberto Luini
- Institute of Biochemistry and Cell Biology, National Research Council, Naples 80131, Italy
| | - Julia von Blume
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510
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Gao M, Liu X, Gu H, Xu H, Zhong W, Wei X, Zhong X. Association between single nucleotide polymorphisms, TGF-β1 promoter methylation, and polycystic ovary syndrome. BMC Pregnancy Childbirth 2024; 24:5. [PMID: 38166771 PMCID: PMC10759533 DOI: 10.1186/s12884-023-06210-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Accepted: 12/17/2023] [Indexed: 01/05/2024] Open
Abstract
BACKGROUND Polycystic ovarian syndrome (PCOS) is a common endocrine and metabolic disease in women. Hyperandrogenaemia (HA) and insulin resistance (IR) are the basic pathophysiological characteristics of PCOS. The aetiology of PCOS has not been fully identified and is generally believed to be related to the combined effects of genetic, metabolic, internal, and external factors. Current studies have not screened for PCOS susceptibility genes in a large population. Here, we aimed to study the effect of TGF-β1 methylation on the clinical PCOS phenotype. METHODS In this study, three generations of family members with PCOS with IR as the main characteristic were selected as research subjects. Through whole exome sequencing and bioinformatic analysis, TGF-β1 was screened as the PCOS susceptibility gene in this family. The epigenetic DNA methylation level of TGF-β1 in peripheral blood was detected by heavy sulfite sequencing in patients with PCOS clinically characterised by IR, and the correlation between the DNA methylation level of the TGF-β1 gene and IR was analysed. We explored whether the degree of methylation of this gene affects IR and whether it participates in the occurrence and development of PCOS. RESULTS The results of this study suggest that the hypomethylation of the CpG4 and CpG7 sites in the TGF-β1 gene promoter may be involved in the pathogenesis of PCOS IR by affecting the expression of the TGF-β1 gene. CONCLUSIONS This study provides new insights into the aetiology and pathogenesis of PCOS.
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Affiliation(s)
- Mengge Gao
- NHC Key Laboratory of Male Reproduction and Genetics, Guangdong Provincial Reproductive Science Institute (Guangdong Provincial Fertility Hospital), Guangzhou, China
- Department of Public Health and Preventive Medicine, School of Medicine, Jinan University, Guangzhou, Guangdong, 510630, China
- Department of Clinical Nutrition, Huadu District People's Hospital, 48 Xinhua Road, Huadu, Guangzhou, Guangdong, 510800, China
| | - Xiaohua Liu
- NHC Key Laboratory of Male Reproduction and Genetics, Guangdong Provincial Reproductive Science Institute (Guangdong Provincial Fertility Hospital), Guangzhou, China
| | - Heng Gu
- NHC Key Laboratory of Male Reproduction and Genetics, Guangdong Provincial Reproductive Science Institute (Guangdong Provincial Fertility Hospital), Guangzhou, China
| | - Hang Xu
- NHC Key Laboratory of Male Reproduction and Genetics, Guangdong Provincial Reproductive Science Institute (Guangdong Provincial Fertility Hospital), Guangzhou, China
- Department of Public Health and Preventive Medicine, School of Medicine, Jinan University, Guangzhou, Guangdong, 510630, China
| | - Wenyao Zhong
- NHC Key Laboratory of Male Reproduction and Genetics, Guangdong Provincial Reproductive Science Institute (Guangdong Provincial Fertility Hospital), Guangzhou, China
| | - Xiangcai Wei
- Department of Public Health and Preventive Medicine, School of Medicine, Jinan University, Guangzhou, Guangdong, 510630, China.
- Guangdong Women and Children Hospital, Guangzhou, China.
| | - Xingming Zhong
- NHC Key Laboratory of Male Reproduction and Genetics, Guangdong Provincial Reproductive Science Institute (Guangdong Provincial Fertility Hospital), Guangzhou, China.
- Department of Public Health and Preventive Medicine, School of Medicine, Jinan University, Guangzhou, Guangdong, 510630, China.
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Moschandrea C, Kondylis V, Evangelakos I, Herholz M, Schneider F, Schmidt C, Yang M, Ehret S, Heine M, Jaeckstein MY, Szczepanowska K, Schwarzer R, Baumann L, Bock T, Nikitopoulou E, Brodesser S, Krüger M, Frezza C, Heeren J, Trifunovic A, Pasparakis M. Mitochondrial dysfunction abrogates dietary lipid processing in enterocytes. Nature 2024; 625:385-392. [PMID: 38123683 PMCID: PMC10781618 DOI: 10.1038/s41586-023-06857-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 11/10/2023] [Indexed: 12/23/2023]
Abstract
Digested dietary fats are taken up by enterocytes where they are assembled into pre-chylomicrons in the endoplasmic reticulum followed by transport to the Golgi for maturation and subsequent secretion to the circulation1. The role of mitochondria in dietary lipid processing is unclear. Here we show that mitochondrial dysfunction in enterocytes inhibits chylomicron production and the transport of dietary lipids to peripheral organs. Mice with specific ablation of the mitochondrial aspartyl-tRNA synthetase DARS2 (ref. 2), the respiratory chain subunit SDHA3 or the assembly factor COX10 (ref. 4) in intestinal epithelial cells showed accumulation of large lipid droplets (LDs) in enterocytes of the proximal small intestine and failed to thrive. Feeding a fat-free diet suppressed the build-up of LDs in DARS2-deficient enterocytes, which shows that the accumulating lipids derive mostly from digested fat. Furthermore, metabolic tracing studies revealed an impaired transport of dietary lipids to peripheral organs in mice lacking DARS2 in intestinal epithelial cells. DARS2 deficiency caused a distinct lack of mature chylomicrons concomitant with a progressive dispersal of the Golgi apparatus in proximal enterocytes. This finding suggests that mitochondrial dysfunction results in impaired trafficking of chylomicrons from the endoplasmic reticulum to the Golgi, which in turn leads to storage of dietary lipids in large cytoplasmic LDs. Taken together, these results reveal a role for mitochondria in dietary lipid transport in enterocytes, which might be relevant for understanding the intestinal defects observed in patients with mitochondrial disorders5.
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Affiliation(s)
- Chrysanthi Moschandrea
- Institute for Genetics, University of Cologne, Cologne, Germany
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Vangelis Kondylis
- Institute for Pathology, Medical Faculty and University Hospital of Cologne, University of Cologne, Cologne, Germany
- Center for Molecular Medicine (CMMC), University of Cologne, Cologne, Germany
| | - Ioannis Evangelakos
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Marija Herholz
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
- Institute for Mitochondrial Diseases and Aging, Medical Faculty, University of Cologne, Cologne, Germany
| | - Farina Schneider
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
- Medical Faculty and University Hospital of Cologne, University of Cologne, Cologne, Germany
| | - Christina Schmidt
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
- Medical Faculty and University Hospital of Cologne, University of Cologne, Cologne, Germany
- MRC Cancer Unit, University of Cambridge, Hutchison/MRC Research Centre, Cambridge Biomedical Campus, Cambridge, UK
| | - Ming Yang
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
- Medical Faculty and University Hospital of Cologne, University of Cologne, Cologne, Germany
- MRC Cancer Unit, University of Cambridge, Hutchison/MRC Research Centre, Cambridge Biomedical Campus, Cambridge, UK
| | - Sandra Ehret
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Markus Heine
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Michelle Y Jaeckstein
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Karolina Szczepanowska
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
- Institute for Mitochondrial Diseases and Aging, Medical Faculty, University of Cologne, Cologne, Germany
| | - Robin Schwarzer
- Institute for Genetics, University of Cologne, Cologne, Germany
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Linda Baumann
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
- Institute for Mitochondrial Diseases and Aging, Medical Faculty, University of Cologne, Cologne, Germany
| | - Theresa Bock
- Institute for Genetics, University of Cologne, Cologne, Germany
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Efterpi Nikitopoulou
- MRC Cancer Unit, University of Cambridge, Hutchison/MRC Research Centre, Cambridge Biomedical Campus, Cambridge, UK
| | - Susanne Brodesser
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Marcus Krüger
- Institute for Genetics, University of Cologne, Cologne, Germany
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Christian Frezza
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
- Medical Faculty and University Hospital of Cologne, University of Cologne, Cologne, Germany
- MRC Cancer Unit, University of Cambridge, Hutchison/MRC Research Centre, Cambridge Biomedical Campus, Cambridge, UK
| | - Joerg Heeren
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Aleksandra Trifunovic
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany.
- Center for Molecular Medicine (CMMC), University of Cologne, Cologne, Germany.
- Institute for Mitochondrial Diseases and Aging, Medical Faculty, University of Cologne, Cologne, Germany.
| | - Manolis Pasparakis
- Institute for Genetics, University of Cologne, Cologne, Germany.
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany.
- Center for Molecular Medicine (CMMC), University of Cologne, Cologne, Germany.
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Wang X, Huang R, Wang Y, Zhou W, Hu Y, Yao Y, Cheng K, Li X, Xu B, Zhang J, Xu Y, Zeng F, Zhu Y, Chen XW. Manganese regulation of COPII condensation controls circulating lipid homeostasis. Nat Cell Biol 2023; 25:1650-1663. [PMID: 37884645 DOI: 10.1038/s41556-023-01260-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Accepted: 09/18/2023] [Indexed: 10/28/2023]
Abstract
Precise control of circulating lipids is instrumental in health and disease. Bulk lipids, carried by specialized lipoproteins, are secreted into the circulation, initially via the coat protein complex II (COPII). How the universal COPII machinery accommodates the abundant yet unconventional lipoproteins remains unclear, let alone its therapeutic translation. Here we report that COPII uses manganese-tuning, self-constrained condensation to selectively drive lipoprotein delivery and set lipid homeostasis in vivo. Serendipitously, adenovirus hijacks the condensation-based transport mechanism, thus enabling the identification of cytosolic manganese as an unexpected control signal. Manganese directly binds the inner COPII coat and enhances its condensation, thereby shifting the assembly-versus-dynamics balance of the transport machinery. Manganese can be mobilized from mitochondria stores to signal COPII, and selectively controls lipoprotein secretion with a distinctive, bell-shaped function. Consequently, dietary titration of manganese enables tailored lipid management that counters pathological dyslipidaemia and atherosclerosis, implicating a condensation-targeting strategy with broad therapeutic potential for cardio-metabolic health.
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Affiliation(s)
- Xiao Wang
- State Key Laboratory of Membrane Biology, Peking University, Beijing, China.
- Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing, China.
- PKU-THU Joint Center for Life Sciences, Peking University, Beijing, China.
| | - Runze Huang
- State Key Laboratory of Membrane Biology, Peking University, Beijing, China
- Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing, China
| | - Yawei Wang
- State Key Laboratory of Membrane Biology, Peking University, Beijing, China
- PKU-THU Joint Center for Life Sciences, Peking University, Beijing, China
| | - Wenjing Zhou
- State Key Laboratory of Membrane Biology, Peking University, Beijing, China
- Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing, China
| | - Yating Hu
- State Key Laboratory of Membrane Biology, Peking University, Beijing, China
- Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing, China
| | - Yuanhang Yao
- State Key Laboratory of Membrane Biology, Peking University, Beijing, China
- Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing, China
| | - Kunlun Cheng
- State Key Laboratory of Membrane Biology, Peking University, Beijing, China
- Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing, China
| | - Xin Li
- State Key Laboratory of Membrane Biology, Peking University, Beijing, China
- Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing, China
| | - Bolin Xu
- State Key Laboratory of Membrane Biology, Peking University, Beijing, China
- Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing, China
| | - Jie Zhang
- Department of Clinical Research Center, Dazhou Hospital, Dazhou, Sichuan, China
| | - Yaowen Xu
- Department of Clinical Research Center, Dazhou Hospital, Dazhou, Sichuan, China
| | - Fanxin Zeng
- Department of Clinical Research Center, Dazhou Hospital, Dazhou, Sichuan, China
| | - Yuangang Zhu
- State Key Laboratory of Membrane Biology, Peking University, Beijing, China
- Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing, China
| | - Xiao-Wei Chen
- State Key Laboratory of Membrane Biology, Peking University, Beijing, China.
- Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing, China.
- PKU-THU Joint Center for Life Sciences, Peking University, Beijing, China.
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6
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Pihlström S, Richardt S, Määttä K, Pekkinen M, Olkkonen VM, Mäkitie O, Mäkitie RE. SGMS2 in primary osteoporosis with facial nerve palsy. Front Endocrinol (Lausanne) 2023; 14:1224318. [PMID: 37886644 PMCID: PMC10598846 DOI: 10.3389/fendo.2023.1224318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Accepted: 09/18/2023] [Indexed: 10/28/2023] Open
Abstract
Pathogenic heterozygous variants in SGMS2 cause a rare monogenic form of osteoporosis known as calvarial doughnut lesions with bone fragility (CDL). The clinical presentations of SGMS2-related bone pathology range from childhood-onset osteoporosis with low bone mineral density and sclerotic doughnut-shaped lesions in the skull to a severe spondylometaphyseal dysplasia with neonatal fractures, long-bone deformities, and short stature. In addition, neurological manifestations occur in some patients. SGMS2 encodes sphingomyelin synthase 2 (SMS2), an enzyme involved in the production of sphingomyelin (SM). This review describes the biochemical structure of SM, SM metabolism, and their molecular actions in skeletal and neural tissue. We postulate how disrupted SM gradient can influence bone formation and how animal models may facilitate a better understanding of SGMS2-related osteoporosis.
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Affiliation(s)
- Sandra Pihlström
- Folkhälsan Institute of Genetics, Helsinki, Finland
- Research Program for Clinical and Molecular Metabolism, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Sampo Richardt
- Folkhälsan Institute of Genetics, Helsinki, Finland
- Research Program for Clinical and Molecular Metabolism, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Kirsi Määttä
- Folkhälsan Institute of Genetics, Helsinki, Finland
- Research Program for Clinical and Molecular Metabolism, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Minna Pekkinen
- Folkhälsan Institute of Genetics, Helsinki, Finland
- Research Program for Clinical and Molecular Metabolism, Faculty of Medicine, University of Helsinki, Helsinki, Finland
- Children´s Hospital, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Vesa M. Olkkonen
- Minerva Foundation Institute for Medical Research, Helsinki, Finland
- Department of Anatomy, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Outi Mäkitie
- Folkhälsan Institute of Genetics, Helsinki, Finland
- Research Program for Clinical and Molecular Metabolism, Faculty of Medicine, University of Helsinki, Helsinki, Finland
- Children´s Hospital, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
- Department of Molecular Medicine and Surgery and Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Riikka E. Mäkitie
- Folkhälsan Institute of Genetics, Helsinki, Finland
- Research Program for Clinical and Molecular Metabolism, Faculty of Medicine, University of Helsinki, Helsinki, Finland
- Department of Otorhinolaryngology – Head and Neck Surgery, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
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7
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Balasubramaniam B, Topalidou I, Kelley M, Meadows SM, Funk O, Ailion M, Fay DS. Effectors of anterior morphogenesis in C. elegans embryos. Biol Open 2023; 12:bio059982. [PMID: 37345480 PMCID: PMC10339035 DOI: 10.1242/bio.059982] [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: 04/23/2023] [Accepted: 06/19/2023] [Indexed: 06/23/2023] Open
Abstract
During embryogenesis the nascent Caenorhabditis elegans epidermis secretes an apical extracellular matrix (aECM) that serves as an external stabilizer, preventing deformation of the epidermis by mechanical forces exerted during morphogenesis. At present, the factors that contribute to aECM function are mostly unknown, including the aECM components themselves, their posttranslational regulators, and the pathways required for their secretion. Here we showed that two proteins previously linked to aECM function, SYM-3/FAM102A and SYM-4/WDR44, colocalize to intracellular and membrane-associated puncta and likely function in a complex. Proteomics experiments also suggested potential roles for SYM-3/FAM102A and SYM-4/WDR44 family proteins in intracellular trafficking. Nonetheless, we found no evidence to support a critical function for SYM-3 or SYM-4 in the apical deposition of two aECM components, NOAH-1 and FBN-1. Moreover, loss of a key splicing regulator of fbn-1, MEC-8/RBPMS2, had surprisingly little effect on the abundance or deposition of FBN-1. Using a focused screening approach, we identified 32 additional proteins that likely contribute to the structure and function of the embryonic aECM. We also characterized morphogenesis defects in embryos lacking mir-51 microRNA family members, which display a similar phenotype to mec-8; sym double mutants. Collectively, these findings add to our knowledge of factors controlling embryonic morphogenesis.
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Affiliation(s)
- Boopathi Balasubramaniam
- Department of Molecular Biology, College of Agriculture, Life Sciences and Natural Resources, University of Wyoming, Laramie 82071-3944, WY, USA
| | - Irini Topalidou
- Department of Biochemistry, University of Washington, Seattle 98195-7350, WA, USA
| | - Melissa Kelley
- Department of Molecular Biology, College of Agriculture, Life Sciences and Natural Resources, University of Wyoming, Laramie 82071-3944, WY, USA
| | - Sarina M. Meadows
- Department of Molecular Biology, College of Agriculture, Life Sciences and Natural Resources, University of Wyoming, Laramie 82071-3944, WY, USA
| | - Owen Funk
- Department of Molecular Biology, College of Agriculture, Life Sciences and Natural Resources, University of Wyoming, Laramie 82071-3944, WY, USA
| | - Michael Ailion
- Department of Biochemistry, University of Washington, Seattle 98195-7350, WA, USA
| | - David S. Fay
- Department of Molecular Biology, College of Agriculture, Life Sciences and Natural Resources, University of Wyoming, Laramie 82071-3944, WY, USA
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8
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Aguilera-Romero A, Lucena R, Sabido-Bozo S, Muñiz M. Impact of sphingolipids on protein membrane trafficking. Biochim Biophys Acta Mol Cell Biol Lipids 2023; 1868:159334. [PMID: 37201864 DOI: 10.1016/j.bbalip.2023.159334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Revised: 04/28/2023] [Accepted: 05/10/2023] [Indexed: 05/20/2023]
Abstract
Membrane trafficking is essential to maintain the spatiotemporal control of protein and lipid distribution within membrane systems of eukaryotic cells. To achieve their functional destination proteins are sorted and transported into lipid carriers that construct the secretory and endocytic pathways. It is an emerging theme that lipid diversity might exist in part to ensure the homeostasis of these pathways. Sphingolipids, a chemical diverse type of lipids with special physicochemical characteristics have been implicated in the selective transport of proteins. In this review, we will discuss current knowledge about how sphingolipids modulate protein trafficking through the endomembrane systems to guarantee that proteins reach their functional destination and the proposed underlying mechanisms.
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Affiliation(s)
- Auxiliadora Aguilera-Romero
- Department of Cell Biology, University of Seville, 41012 Seville, Spain; Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Spain.
| | - Rafael Lucena
- Department of Cell Biology, University of Seville, 41012 Seville, Spain; Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Spain
| | - Susana Sabido-Bozo
- Department of Cell Biology, University of Seville, 41012 Seville, Spain; Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Spain
| | - Manuel Muñiz
- Department of Cell Biology, University of Seville, 41012 Seville, Spain; Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Spain.
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9
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Boopathi B, Topalidou I, Kelley M, Meadows SM, Funk O, Ailion M, Fay DS. Pathways that affect anterior morphogenesis in C. elegans embryos. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.23.537986. [PMID: 37163004 PMCID: PMC10168279 DOI: 10.1101/2023.04.23.537986] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
During embryogenesis the nascent Caenorhabditis elegans epidermis secretes an apical extracellular matrix (aECM) that serves as an external stabilizer, preventing deformation of the epidermis by mechanical forces exerted during morphogenesis. We showed that two conserved proteins linked to this process, SYM-3/FAM102A and SYM-4/WDR44, colocalize to intracellular and membrane-associated puncta and likely function together in a complex. Proteomics data also suggested potential roles for FAM102A and WDR44 family proteins in intracellular trafficking, consistent with their localization patterns. Nonetheless, we found no evidence to support a clear function for SYM-3 or SYM-4 in the apical deposition of two aECM components, FBN-1 and NOAH. Surprisingly, loss of MEC-8/RBPMS2, a conserved splicing factor and regulator of fbn-1 , had little effect on the abundance or deposition of FBN-1 to the aECM. Using a focused screening approach, we identified 32 additional proteins that likely contribute to the structure and function of the embryonic aECM. Lastly, we examined morphogenesis defects in embryos lacking mir-51 microRNA family members, which display a related embryonic phenotype to mec-8; sym double mutants. Collectively, our findings add to our knowledge of pathways controlling embryonic morphogenesis. SUMMARY STATEMENT We identify new proteins in apical ECM biology in C. elegans and provide evidence that SYM-3/FAM102A and SYM-4/WDR44 function together in trafficking but do not regulate apical ECM protein deposition.
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Affiliation(s)
- Balasubramaniam Boopathi
- Department of Molecular Biology, College of Agriculture, Life Sciences and Natural Resources, University of Wyoming, Laramie, Wyoming, United States of America
| | - Irini Topalidou
- Department of Biochemistry, University of Washington, Seattle, United States of America
| | - Melissa Kelley
- Department of Molecular Biology, College of Agriculture, Life Sciences and Natural Resources, University of Wyoming, Laramie, Wyoming, United States of America
| | - Sarina M Meadows
- Department of Molecular Biology, College of Agriculture, Life Sciences and Natural Resources, University of Wyoming, Laramie, Wyoming, United States of America
| | - Owen Funk
- Department of Molecular Biology, College of Agriculture, Life Sciences and Natural Resources, University of Wyoming, Laramie, Wyoming, United States of America
| | - Michael Ailion
- Department of Biochemistry, University of Washington, Seattle, United States of America
| | - David S Fay
- Department of Molecular Biology, College of Agriculture, Life Sciences and Natural Resources, University of Wyoming, Laramie, Wyoming, United States of America
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10
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Sun J, Mai K, Ai Q. Effects of GRP78 on Endoplasmic Reticulum Stress and Inflammatory Response in Macrophages of Large Yellow Croaker ( Larimichthys crocea). Int J Mol Sci 2023; 24:ijms24065855. [PMID: 36982929 PMCID: PMC10054070 DOI: 10.3390/ijms24065855] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 03/05/2023] [Accepted: 03/07/2023] [Indexed: 03/30/2023] Open
Abstract
Endoplasmic reticulum (ER) homeostasis plays a vital role in cell physiological functions. Various factors can destroy the homeostasis of the ER and cause ER stress. Moreover, ER stress is often related to inflammation. Glucose-regulated protein 78 (GRP78) is an ER chaperone, which plays a vital role in maintaining cellular homeostasis. Nevertheless, the potential effects of GRP78 on ER stress and inflammation is still not fully elucidated in fish. In the present study, ER stress and inflammation was induced by tunicamycin (TM) or palmitic acid (PA) in the macrophages of large yellow croakers. GRP78 was treated with an agonist/inhibitor before or after the TM/PA treatment. The results showed that the TM/PA treatment could significantly induce ER stress and an inflammatory response in the macrophages of large yellow croakers whereas the incubation of the GRP78 agonist could reduce TM/PA-induced ER stress and an inflammatory response. Moreover, the incubation of the GRP78 inhibitor could further induce TM/PA-induced ER stress and an inflammatory response. These results provide an innovative idea to explain the relationship between GRP78 and TM/PA-induced ER stress or inflammation in large yellow croakers.
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Affiliation(s)
- Jie Sun
- Key Laboratory of Aquaculture Nutrition and Feed (Ministry of Agriculture and Rural Affairs), Key Laboratory of Mariculture (Ministry of Education), Ocean University of China, 5 Yushan Road, Qingdao 266003, China
| | - Kangsen Mai
- Key Laboratory of Aquaculture Nutrition and Feed (Ministry of Agriculture and Rural Affairs), Key Laboratory of Mariculture (Ministry of Education), Ocean University of China, 5 Yushan Road, Qingdao 266003, China
- Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, 1 Wenhai Road, Qingdao 266237, China
| | - Qinghui Ai
- Key Laboratory of Aquaculture Nutrition and Feed (Ministry of Agriculture and Rural Affairs), Key Laboratory of Mariculture (Ministry of Education), Ocean University of China, 5 Yushan Road, Qingdao 266003, China
- Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, 1 Wenhai Road, Qingdao 266237, China
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11
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Barrabi C, Zhang K, Liu M, Chen X. Pancreatic beta cell ER export in health and diabetes. Front Endocrinol (Lausanne) 2023; 14:1155779. [PMID: 37152949 PMCID: PMC10160654 DOI: 10.3389/fendo.2023.1155779] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Accepted: 04/10/2023] [Indexed: 05/09/2023] Open
Abstract
In the secretory pathway of the pancreatic beta cell, proinsulin and other secretory granule proteins are first produced in the endoplasmic reticulum (ER). Beta cell ER homeostasis is vital for normal beta cell functions and is maintained by the delicate balance between protein synthesis, folding, export and degradation. Disruption of ER homeostasis leads to beta cell death and diabetes. Among the four components to maintain ER homeostasis, the role of ER export in insulin biogenesis or beta cell survival was not well-understood. COPII (coat protein complex II) dependent transport is a conserved mechanism for most cargo proteins to exit ER and transport to Golgi apparatus. Emerging evidence began to reveal a critical role of COPII-dependent ER export in beta cells. In this review, we will first discuss the basic components of the COPII transport machinery, the regulation of cargo entry and COPII coat assembly in mammalian cells, and the general concept of receptor-mediated cargo sorting in COPII vesicles. On the basis of these general discussions, the current knowledge and recent developments specific to the beta cell COPII dependent ER export are summarized under normal and diabetic conditions.
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Affiliation(s)
- Cesar Barrabi
- Department of Physiology, School of Medicine, Wayne State University, Detroit, MI, United States
| | - Kezhong Zhang
- Center for Molecular Medicine and Genetics, School of Medicine, Wayne State University, Detroit, MI, United States
| | - Ming Liu
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Xuequn Chen
- Department of Physiology, School of Medicine, Wayne State University, Detroit, MI, United States
- *Correspondence: Xuequn Chen,
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12
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Cui L, Li H, Xi Y, Hu Q, Liu H, Fan J, Xiang Y, Zhang X, Shui W, Lai Y. Vesicle trafficking and vesicle fusion: mechanisms, biological functions, and their implications for potential disease therapy. MOLECULAR BIOMEDICINE 2022; 3:29. [PMID: 36129576 PMCID: PMC9492833 DOI: 10.1186/s43556-022-00090-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Accepted: 07/12/2022] [Indexed: 11/10/2022] Open
Abstract
Intracellular vesicle trafficking is the fundamental process to maintain the homeostasis of membrane-enclosed organelles in eukaryotic cells. These organelles transport cargo from the donor membrane to the target membrane through the cargo containing vesicles. Vesicle trafficking pathway includes vesicle formation from the donor membrane, vesicle transport, and vesicle fusion with the target membrane. Coat protein mediated vesicle formation is a delicate membrane budding process for cargo molecules selection and package into vesicle carriers. Vesicle transport is a dynamic and specific process for the cargo containing vesicles translocation from the donor membrane to the target membrane. This process requires a group of conserved proteins such as Rab GTPases, motor adaptors, and motor proteins to ensure vesicle transport along cytoskeletal track. Soluble N-ethyl-maleimide-sensitive factor (NSF) attachment protein receptors (SNARE)-mediated vesicle fusion is the final process for vesicle unloading the cargo molecules at the target membrane. To ensure vesicle fusion occurring at a defined position and time pattern in eukaryotic cell, multiple fusogenic proteins, such as synaptotagmin (Syt), complexin (Cpx), Munc13, Munc18 and other tethering factors, cooperate together to precisely regulate the process of vesicle fusion. Dysfunctions of the fusogenic proteins in SNARE-mediated vesicle fusion are closely related to many diseases. Recent studies have suggested that stimulated membrane fusion can be manipulated pharmacologically via disruption the interface between the SNARE complex and Ca2+ sensor protein. Here, we summarize recent insights into the molecular mechanisms of vesicle trafficking, and implications for the development of new therapeutics based on the manipulation of vesicle fusion.
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13
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Sar1 Affects the Localization of Perilipin 2 to Lipid Droplets. Int J Mol Sci 2022; 23:ijms23126366. [PMID: 35742827 PMCID: PMC9223735 DOI: 10.3390/ijms23126366] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 06/03/2022] [Accepted: 06/03/2022] [Indexed: 02/05/2023] Open
Abstract
Lipid droplets (LDs) are intracellular organelles that are ubiquitous in many types of cells. The LD core consists of triacylglycerols (TGs) surrounded by a phospholipid monolayer and surface proteins such as perilipin 2 (PLIN2). Although TGs accumulate in the phospholipid bilayer of the endoplasmic reticulum (ER) and subsequently nascent LDs buds from ER, the mechanism by which LD proteins are transported to LD particles is not fully understood. Sar1 is a GTPase known as a regulator of coat protein complex Ⅱ (COPⅡ) vesicle budding, and its role in LD formation was investigated in this study. HuH7 human hepatoma cells were infected with adenoviral particles containing genes coding GFP fused with wild-type Sar1 (Sar1 WT) or a GTPase mutant form (Sar1 H79G). When HuH7 cells were treated with oleic acid, Sar1 WT formed a ring-like structure around the LDs. The transient expression of Sar1 did not significantly alter the levels of TG and PLIN2 in the cells. However, the localization of PLIN2 to the LDs decreased in the cells expressing Sar1 H79G. Furthermore, the effects of Sar1 on PLIN2 localization to the LDs were verified by the suppression of endogenous Sar1 using the short hairpin RNA technique. In conclusion, it was found that Sar1 has some roles in the intracellular distribution of PLIN2 to LDs in liver cells.
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14
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Nakano A. The Golgi Apparatus and its Next-Door Neighbors. Front Cell Dev Biol 2022; 10:884360. [PMID: 35573670 PMCID: PMC9096111 DOI: 10.3389/fcell.2022.884360] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2022] [Accepted: 03/28/2022] [Indexed: 12/20/2022] Open
Abstract
The Golgi apparatus represents a central compartment of membrane traffic. Its apparent architecture, however, differs considerably among species, from unstacked and scattered cisternae in the budding yeast Saccharomyces cerevisiae to beautiful ministacks in plants and further to gigantic ribbon structures typically seen in mammals. Considering the well-conserved functions of the Golgi, its fundamental structure must have been optimized despite seemingly different architectures. In addition to the core layers of cisternae, the Golgi is usually accompanied by next-door compartments on its cis and trans sides. The trans-Golgi network (TGN) can be now considered as a compartment independent from the Golgi stack. On the cis side, the intermediate compartment between the ER and the Golgi (ERGIC) has been known in mammalian cells, and its functional equivalent is now suggested for yeast and plant cells. High-resolution live imaging is extremely powerful for elucidating the dynamics of these compartments and has revealed amazing similarities in their behaviors, indicating common mechanisms conserved along the long course of evolution. From these new findings, I would like to propose reconsideration of compartments and suggest a new concept to describe their roles comprehensively around the Golgi and in the post-Golgi trafficking.
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15
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Aguilera-Romero A, Muñiz M. A Role for Lipids in Protein Sorting? Chimia (Aarau) 2021; 75:1026-1030. [PMID: 34920772 DOI: 10.2533/chimia.2021.1026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Lipid and protein diversity provides structural and functional identity to the membrane compartments that define the eukaryotic cell. This compositional heterogeneity is maintained by the secretory pathway, which feeds newly synthesized proteins and lipids to the endomembrane systems. The precise sorting of lipids and proteins through the pathway guarantees the achievement of their correct delivery. Although proteins have been shown to be key for sorting mechanisms, whether and how lipids contribute to this process is still an open discussion. Our laboratory, in collaboration with other groups, has recently addressed the long-postulated role of membrane lipids in protein sorting in the secretory pathway, by investigating in yeast how a special class of lipid-linked cell surface proteins are differentially exported from the endoplasmic reticulum. Here we comment on this interdisciplinary study that highlights the role of lipid diversity and the importance of protein-lipid interactions in sorting processes at the cell membrane.
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Affiliation(s)
| | - Manuel Muñiz
- Dept. Cell Biology, University of Seville, Seville, 41012 Spain;,
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16
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Fang W, Chen Q, Li J, Liu Y, Zhao Z, Shen Y, Mai K, Ai Q. Endoplasmic Reticulum Stress Disturbs Lipid Homeostasis and Augments Inflammation in the Intestine and Isolated Intestinal Cells of Large Yellow Croaker ( Larimichthys crocea). Front Immunol 2021; 12:738143. [PMID: 34489982 PMCID: PMC8417523 DOI: 10.3389/fimmu.2021.738143] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Accepted: 07/30/2021] [Indexed: 12/14/2022] Open
Abstract
The small intestine is crucial for lipid homeostasis and immune regulation of the whole body. Endoplasmic reticulum (ER) stress may affect lipid metabolism and inflammation in the intestine, but the potential mechanism is not completely understood. In the present study, intraperitoneal injection of tunicamycin (TM) induced ER stress in the intestine of large yellow croaker (Larimichthys crocea). ER stress induced excessive accumulation of triglyceride (TG) in the intestine by promoting lipid synthesis. However, it also enhanced lipid secretion and fatty acid β-oxidation. In addition, ER stress augmented inflammation in the intestine by promoting p65 into the nucleus and increasing proinflammatory genes expression. In the isolated intestinal cells, the obtained results showed that TM treatment significantly upregulated the mRNA expression of lipid synthesis and inflammatory response genes, which were consistent with those in vivo. Moreover, overexpression of unfolded protein response (UPR) sensors significantly upregulated promoter activities of lipid synthesis and proinflammatory genes. In conclusion, the results suggested that ER stress disturbed lipid metabolism and augmented inflammation in the intestine and isolated intestinal cells of large yellow croaker, which may contribute to finding novel therapies to tackle lipid dysregulation and inflammation in the intestine of fish and human beings.
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Affiliation(s)
- Wei Fang
- Key Laboratory of Aquaculture Nutrition and Feed (Ministry of Agriculture and Rural Affairs) and Key Laboratory of Mariculture (Ministry of Education), Ocean University of China, Qingdao, China
| | - Qiuchi Chen
- Key Laboratory of Aquaculture Nutrition and Feed (Ministry of Agriculture and Rural Affairs) and Key Laboratory of Mariculture (Ministry of Education), Ocean University of China, Qingdao, China
| | - Jiamin Li
- Key Laboratory of Aquaculture Nutrition and Feed (Ministry of Agriculture and Rural Affairs) and Key Laboratory of Mariculture (Ministry of Education), Ocean University of China, Qingdao, China
| | - Yongtao Liu
- Key Laboratory of Aquaculture Nutrition and Feed (Ministry of Agriculture and Rural Affairs) and Key Laboratory of Mariculture (Ministry of Education), Ocean University of China, Qingdao, China
| | - Zengqi Zhao
- Key Laboratory of Aquaculture Nutrition and Feed (Ministry of Agriculture and Rural Affairs) and Key Laboratory of Mariculture (Ministry of Education), Ocean University of China, Qingdao, China
| | - Yanan Shen
- Key Laboratory of Aquaculture Nutrition and Feed (Ministry of Agriculture and Rural Affairs) and Key Laboratory of Mariculture (Ministry of Education), Ocean University of China, Qingdao, China
| | - Kangsen Mai
- Key Laboratory of Aquaculture Nutrition and Feed (Ministry of Agriculture and Rural Affairs) and Key Laboratory of Mariculture (Ministry of Education), Ocean University of China, Qingdao, China.,Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Qinghui Ai
- Key Laboratory of Aquaculture Nutrition and Feed (Ministry of Agriculture and Rural Affairs) and Key Laboratory of Mariculture (Ministry of Education), Ocean University of China, Qingdao, China.,Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
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17
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Huang D, Xu B, Liu L, Wu L, Zhu Y, Ghanbarpour A, Wang Y, Chen FJ, Lyu J, Hu Y, Kang Y, Zhou W, Wang X, Ding W, Li X, Jiang Z, Chen J, Zhang X, Zhou H, Li JZ, Guo C, Zheng W, Zhang X, Li P, Melia T, Reinisch K, Chen XW. TMEM41B acts as an ER scramblase required for lipoprotein biogenesis and lipid homeostasis. Cell Metab 2021; 33:1655-1670.e8. [PMID: 34015269 DOI: 10.1016/j.cmet.2021.05.006] [Citation(s) in RCA: 66] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 04/06/2021] [Accepted: 05/05/2021] [Indexed: 02/06/2023]
Abstract
How amphipathic phospholipids are shuttled between the membrane bilayer remains an essential but elusive process, particularly at the endoplasmic reticulum (ER). One prominent phospholipid shuttling process concerns the biogenesis of APOB-containing lipoproteins within the ER lumen, which may require bulk trans-bilayer movement of phospholipids from the cytoplasmic leaflet of the ER bilayer. Here, we show that TMEM41B, present in the lipoprotein export machinery, encodes a previously conceptualized ER lipid scramblase mediating trans-bilayer shuttling of bulk phospholipids. Loss of hepatic TMEM41B eliminates plasma lipids, due to complete absence of mature lipoproteins within the ER, but paradoxically also activates lipid production. Mechanistically, scramblase deficiency triggers unique ER morphological changes and unsuppressed activation of SREBPs, which potently promotes lipid synthesis despite stalled secretion. Together, this response induces full-blown nonalcoholic hepatosteatosis in the TMEM41B-deficient mice within weeks. Collectively, our data uncovered a fundamental mechanism safe-guarding ER function and integrity, dysfunction of which disrupts lipid homeostasis.
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Affiliation(s)
- Dong Huang
- State Key Laboratory of Membrane Biology, Peking University, Beijing 100871, China; Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing 100871, China
| | - Bolin Xu
- State Key Laboratory of Membrane Biology, Peking University, Beijing 100871, China; Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing 100871, China
| | - Lu Liu
- State Key Laboratory of Membrane Biology, Peking University, Beijing 100871, China; Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing 100871, China
| | - Lingzhi Wu
- Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing 100871, China
| | - Yuangang Zhu
- Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing 100871, China
| | - Alireza Ghanbarpour
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Yawei Wang
- Center for Life Sciences, Peking University, Beijing 100871, China
| | - Feng-Jung Chen
- Institute of Metabolism and Integrative Biology, Fudan University, Shanghai 200438, China
| | - Jia Lyu
- Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing 100871, China
| | - Yating Hu
- Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing 100871, China
| | - Yunlu Kang
- Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing 100871, China
| | - Wenjing Zhou
- Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing 100871, China
| | - Xiao Wang
- Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing 100871, China
| | - Wanqiu Ding
- Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing 100871, China
| | - Xin Li
- Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing 100871, China
| | - Zhaodi Jiang
- National Institute of Biological Sciences, Tsinghua University, Beijing 100086, China
| | - Jizheng Chen
- Guangzhou Institute of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510503, China
| | - Xu Zhang
- The Key Laboratory of Rare Metabolic Disease, Department of Biochemistry and Molecular Biology, The Key Laboratory of Human Functional Genomics of Jiangsu Province, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Hongwen Zhou
- Department of Endocrinology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China
| | - John Zhong Li
- The Key Laboratory of Rare Metabolic Disease, Department of Biochemistry and Molecular Biology, The Key Laboratory of Human Functional Genomics of Jiangsu Province, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Chunguang Guo
- Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing 100871, China
| | - Wen Zheng
- Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing 100871, China
| | - Xiuqin Zhang
- Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing 100871, China
| | - Peng Li
- Institute of Metabolism and Integrative Biology, Fudan University, Shanghai 200438, China; School of Life Sciences, Tsinghua University, Beijing 100086, China
| | - Thomas Melia
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Karin Reinisch
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Xiao-Wei Chen
- State Key Laboratory of Membrane Biology, Peking University, Beijing 100871, China; Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing 100871, China; Center for Life Sciences, Peking University, Beijing 100871, China.
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18
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Lemus L, Matić Z, Gal L, Fadel A, Schuldiner M, Goder V. Post-ER degradation of misfolded GPI-anchored proteins is linked with microautophagy. Curr Biol 2021; 31:4025-4037.e5. [PMID: 34314677 DOI: 10.1016/j.cub.2021.06.078] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 06/07/2021] [Accepted: 06/25/2021] [Indexed: 01/08/2023]
Abstract
Glycosylphosphatidylinositol-anchored proteins (GPI-APs) are membrane-conjugated cell-surface proteins with diverse structural, developmental, and signaling functions and clinical relevance. Typically, after biosynthesis and attachment to the preassembled GPI anchor, GPI-APs rapidly leave the endoplasmic reticulum (ER) and rely on post-ER quality control. Terminally misfolded GPI-APs end up inside the vacuole/lysosome for degradation, but their trafficking itinerary to this organelle and the processes linked to their uptake by the vacuole/lysosome remain uncharacterized. In a yeast mutant that is lacking Pep4, a key vacuolar protease, several misfolded model GPI-APs accumulated in the vacuolar membrane. In the same mutant, macroautophagy and the multi-vesicular body (MVB) pathway were intact, hinting at a hitherto-unknown trafficking pathway for the degradation of misfolded GPI-APs. To unravel it, we used a genome-wide screen coupled to high-throughput fluorescence microscopy and followed the fate of the misfolded GPI-AP: Gas1∗. We found that components of the early secretory and endocytic pathways are involved in its targeting to the vacuole and that vacuolar transporter chaperones (VTCs), with roles in microautophagy, negatively affect the vacuolar uptake of Gas1∗. In support, we demonstrate that Gas1∗ internalizes from vacuolar membranes into membrane-bound intravacuolar vesicles prior to degradation. Our data link post-ER degradation with microautophagy.
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Affiliation(s)
- Leticia Lemus
- Department of Genetics, University of Seville, Ave Reina Mercedes, 6, 41012 Seville, Spain.
| | - Zrinka Matić
- Department of Genetics, University of Seville, Ave Reina Mercedes, 6, 41012 Seville, Spain
| | - Lihi Gal
- Department of Molecular Genetics, Meyer Bldg. Room 122, Weizmann Institute of Sciences, 76100 Rehovot, Israel
| | - Amir Fadel
- Department of Molecular Genetics, Meyer Bldg. Room 122, Weizmann Institute of Sciences, 76100 Rehovot, Israel
| | - Maya Schuldiner
- Department of Molecular Genetics, Meyer Bldg. Room 122, Weizmann Institute of Sciences, 76100 Rehovot, Israel
| | - Veit Goder
- Department of Genetics, University of Seville, Ave Reina Mercedes, 6, 41012 Seville, Spain.
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Receptor-Mediated ER Export of Lipoproteins Controls Lipid Homeostasis in Mice and Humans. Cell Metab 2021; 33:350-366.e7. [PMID: 33186557 DOI: 10.1016/j.cmet.2020.10.020] [Citation(s) in RCA: 48] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2020] [Revised: 08/24/2020] [Accepted: 10/20/2020] [Indexed: 12/14/2022]
Abstract
Efficient delivery of specific cargos in vivo poses a major challenge to the secretory pathway, which shuttles products encoded by ∼30% of the genome. Newly synthesized protein and lipid cargos embark on the secretory pathway via COPII-coated vesicles, assembled by the GTPase SAR1 on the endoplasmic reticulum (ER), but how lipid-carrying lipoproteins are distinguished from the general protein cargos in the ER and selectively secreted has not been clear. Here, we show that this process is quantitatively governed by the GTPase SAR1B and SURF4, a high-efficiency cargo receptor. While both genes are implicated in lipid regulation in humans, hepatic inactivation of either mouse Sar1b or Surf4 selectively depletes plasma lipids to near-zero and protects the mice from atherosclerosis. These findings show that the pairing between SURF4 and SAR1B synergistically operates a specialized, dosage-sensitive transport program for circulating lipids, while further suggesting a potential translation to treat atherosclerosis and related cardio-metabolic diseases.
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20
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Kimura AK, Kimura T. Phosphatidylserine biosynthesis pathways in lipid homeostasis: Toward resolution of the pending central issue for decades. FASEB J 2020; 35:e21177. [PMID: 33205488 DOI: 10.1096/fj.202001802r] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 10/17/2020] [Accepted: 10/26/2020] [Indexed: 12/28/2022]
Abstract
Enzymatic control of lipid homeostasis in the cell is a vital element in the complex organization of life. Phosphatidylserine (PS) is an essential anionic phospholipid of cell membranes, and conducts numerous roles for their structural and functional integrity. In mammalian cells, two distinct enzymes phosphatidylserine synthases-1 (PSS1) and -2 (PSS2) in the mitochondria-associated membrane (MAM) in the ER perform de novo synthesis of PS. It is based on base-exchange reactions of the preexisting dominant phospholipids phosphatidylcholine (PC) and phosphatidylethanolamine (PE). While PSS2 specifically catalyzes the reaction "PE → PS," whether or not PSS1 is responsible for the same reaction along with the reaction "PC → PS" remains unsettled despite its fundamental impact on the major stoichiometry. We propose here that a key but the only report that appeared to have put scientists on hold for decades in answering to this issue may be viewed consistently with other available research reports; PSS1 utilizes the two dominant phospholipid classes at a similar intrinsic rate. In this review, we discuss the issue in view of the current information for the enzyme machineries, membrane structure and dynamics, intracellular network of lipid transport, and PS synthesis in health and disease. Resolution of the pending issue is thus critical in advancing our understanding of roles of the essential anionic lipid in biology, health, and disease.
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Affiliation(s)
- Atsuko K Kimura
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON, Canada
| | - Tomohiro Kimura
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON, Canada
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21
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Analysis of Low Molecular Weight Substances and Related Processes Influencing Cellular Cholesterol Efflux. Pharmaceut Med 2020; 33:465-498. [PMID: 31933239 PMCID: PMC7101889 DOI: 10.1007/s40290-019-00308-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Cholesterol efflux is the key process protecting the vascular system from the development of atherosclerotic lesions. Various extracellular and intracellular events affect the ability of the cell to efflux excess cholesterol. To explore the possible pathways and processes that promote or inhibit cholesterol efflux, we applied a combined cheminformatic and bioinformatic approach. We performed a comprehensive analysis of published data on the various substances influencing cholesterol efflux and found 153 low molecular weight substances that are included in the Chemical Entities of Biological Interest (ChEBI) database. Pathway enrichment was performed for substances identified within the Reactome database, and 45 substances were selected in 93 significant pathways. The most common pathways included the energy-dependent processes related to active cholesterol transport from the cell, lipoprotein metabolism and lipid transport, and signaling pathways. The activators and inhibitors of cholesterol efflux were non-uniformly distributed among the different pathways: the substances influencing ‘biological oxidations’ activate cholesterol efflux and the substances influencing ‘Signaling by GPCR and PTK6’ inhibit efflux. This analysis may be used in the search and design of efflux effectors for therapies targeting structural and functional high-density lipoprotein deficiency.
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22
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Zhang IX, Ren J, Vadrevu S, Raghavan M, Satin LS. ER stress increases store-operated Ca 2+ entry (SOCE) and augments basal insulin secretion in pancreatic beta cells. J Biol Chem 2020; 295:5685-5700. [PMID: 32179650 PMCID: PMC7186166 DOI: 10.1074/jbc.ra120.012721] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Revised: 03/06/2020] [Indexed: 12/13/2022] Open
Abstract
Type 2 diabetes mellitus (T2DM) is characterized by impaired glucose-stimulated insulin secretion and increased peripheral insulin resistance. Unremitting endoplasmic reticulum (ER) stress can lead to beta-cell apoptosis and has been linked to type 2 diabetes. Although many studies have attempted to link ER stress and T2DM, the specific effects of ER stress on beta-cell function remain incompletely understood. To determine the interrelationship between ER stress and beta-cell function, here we treated insulin-secreting INS-1(832/13) cells or isolated mouse islets with the ER stress-inducer tunicamycin (TM). TM induced ER stress as expected, as evidenced by activation of the unfolded protein response. Beta cells treated with TM also exhibited concomitant alterations in their electrical activity and cytosolic free Ca2+ oscillations. As ER stress is known to reduce ER Ca2+ levels, we tested the hypothesis that the observed increase in Ca2+ oscillations occurred because of reduced ER Ca2+ levels and, in turn, increased store-operated Ca2+ entry. TM-induced cytosolic Ca2+ and membrane electrical oscillations were acutely inhibited by YM58483, which blocks store-operated Ca2+ channels. Significantly, TM-treated cells secreted increased insulin under conditions normally associated with only minimal release, e.g. 5 mm glucose, and YM58483 blocked this secretion. Taken together, these results support a critical role for ER Ca2+ depletion-activated Ca2+ current in mediating Ca2+-induced insulin secretion in response to ER stress.
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Affiliation(s)
- Irina X Zhang
- Department of Pharmacology and Brehm Diabetes Research Center, University of Michigan Medical School, Ann Arbor, Michigan 48105
| | - Jianhua Ren
- Department of Pharmacology and Brehm Diabetes Research Center, University of Michigan Medical School, Ann Arbor, Michigan 48105
| | | | - Malini Raghavan
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan 48109
| | - Leslie S Satin
- Department of Pharmacology and Brehm Diabetes Research Center, University of Michigan Medical School, Ann Arbor, Michigan 48105.
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23
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Chen L, Chen XW, Huang X, Song BL, Wang Y, Wang Y. Regulation of glucose and lipid metabolism in health and disease. SCIENCE CHINA-LIFE SCIENCES 2019; 62:1420-1458. [PMID: 31686320 DOI: 10.1007/s11427-019-1563-3] [Citation(s) in RCA: 130] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Accepted: 10/15/2019] [Indexed: 02/08/2023]
Abstract
Glucose and fatty acids are the major sources of energy for human body. Cholesterol, the most abundant sterol in mammals, is a key component of cell membranes although it does not generate ATP. The metabolisms of glucose, fatty acids and cholesterol are often intertwined and regulated. For example, glucose can be converted to fatty acids and cholesterol through de novo lipid biosynthesis pathways. Excessive lipids are secreted in lipoproteins or stored in lipid droplets. The metabolites of glucose and lipids are dynamically transported intercellularly and intracellularly, and then converted to other molecules in specific compartments. The disorders of glucose and lipid metabolism result in severe diseases including cardiovascular disease, diabetes and fatty liver. This review summarizes the major metabolic aspects of glucose and lipid, and their regulations in the context of physiology and diseases.
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Affiliation(s)
- Ligong Chen
- School of Pharmaceutical Sciences, Beijing Advanced Innovation Center for Structural Biology, Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology (Ministry of Education), Tsinghua University, Beijing, 100084, China.
| | - Xiao-Wei Chen
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, 100871, China.
| | - Xun Huang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China.
| | - Bao-Liang Song
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, 430072, China.
| | - Yan Wang
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, 430072, China.
| | - Yiguo Wang
- MOE Key Laboratory of Bioinformatics, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, 100084, China.
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24
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Jing J, Wang B, Liu P. The Functional Role of SEC23 in Vesicle Transportation, Autophagy and Cancer. Int J Biol Sci 2019; 15:2419-2426. [PMID: 31595159 PMCID: PMC6775307 DOI: 10.7150/ijbs.37008] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2019] [Accepted: 08/01/2019] [Indexed: 02/06/2023] Open
Abstract
SEC23, the core component of the coat protein complex II (COPII), functions to transport newly synthesized proteins and lipids from the endoplasmic reticulum (ER) to the Golgi apparatus in cells for secretion. SEC23 protein has two isoforms (SEC23A and SEC23B) and their aberrant expression and mutations were reported to cause human diseases and oncogenesis, whereas SEC23A and SEC23B may have the opposite activity in human cancer, for a reason that remains unclear. This review summarizes recent research in SEC23, COPII-vesicle transportation, autophagy, and cancer.
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Affiliation(s)
- Jingchen Jing
- Center for Translational Medicine, The First Affiliated Hospital, Xi'an Jiaotong University.,The Key Laboratory for Tumor Precision Medicine of Shaanxi Province, The First Affiliated Hospital, Xi'an Jiaotong University, Xi'an, Shaanxi 710061, China
| | - Bo Wang
- Center for Translational Medicine, The First Affiliated Hospital, Xi'an Jiaotong University.,The Key Laboratory for Tumor Precision Medicine of Shaanxi Province, The First Affiliated Hospital, Xi'an Jiaotong University, Xi'an, Shaanxi 710061, China
| | - Peijun Liu
- Center for Translational Medicine, The First Affiliated Hospital, Xi'an Jiaotong University.,The Key Laboratory for Tumor Precision Medicine of Shaanxi Province, The First Affiliated Hospital, Xi'an Jiaotong University, Xi'an, Shaanxi 710061, China
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25
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Funato K, Riezman H, Muñiz M. Vesicular and non-vesicular lipid export from the ER to the secretory pathway. Biochim Biophys Acta Mol Cell Biol Lipids 2019; 1865:158453. [PMID: 31054928 DOI: 10.1016/j.bbalip.2019.04.013] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 12/20/2018] [Accepted: 01/06/2019] [Indexed: 11/26/2022]
Abstract
The endoplasmic reticulum is the site of synthesis of most glycerophospholipids, neutral lipids and the initial steps of sphingolipid biosynthesis of the secretory pathway. After synthesis, these lipids are distributed within the cells to create and maintain the specific compositions of the other secretory organelles. This represents a formidable challenge, particularly while there is a simultaneous and quantitatively important flux of membrane components stemming from the vesicular traffic of proteins through the pathway, which can also vary depending on the cell type and status. To meet this challenge cells have developed an intricate system of interorganellar contacts and lipid transport proteins, functioning in non-vesicular lipid transport, which are able to ensure membrane lipid homeostasis even in the absence of membrane trafficking. Nevertheless, under normal conditions, lipids are transported in cells by both vesicular and non-vesicular mechanisms. In this review we will discuss the mechanism and roles of vesicular and non-vesicular transport of lipids from the ER to other organelles of the secretory pathway.
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Affiliation(s)
- Kouichi Funato
- Department of Bioresource Science and Technology, Hiroshima University, Japan.
| | - Howard Riezman
- NCCR Chemical Biology and Department of Biochemistry, Sciences II, University of Geneva, Switzerland.
| | - Manuel Muñiz
- Department of Cell Biology, University of Seville, 41012 Seville, Spain; Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Spain.
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26
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Choi SR, Hwang YL, Kim SJ, Sohn KC, Choi CW, Park KD, Lee Y, Seo YJ, Lee JH, Hong SP, Seo SJ, Kim SJ, Kim CD. Tropomyosin-receptor kinase fused gene (TFG) regulates lipid production in human sebocytes. Sci Rep 2019; 9:6587. [PMID: 31036933 PMCID: PMC6488642 DOI: 10.1038/s41598-019-43209-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Accepted: 04/17/2019] [Indexed: 11/17/2022] Open
Abstract
The endoplasmic reticulum (ER) is an organelle in which important cellular events such as protein synthesis and lipid production occur. Although many lipid molecules are produced in the ER, the effect of ER-organizing proteins on lipid synthesis in sebocytes has not been completely elucidated. Tropomyosin-receptor kinase fused gene (TFG) is located in ER exit sites and participates in COPII-coated vesicle formation along with many scaffold proteins, such as Sec. 13 and Sec. 16. In this study, we investigated the putative role of TFG in lipid production in sebocytes using an immortalized human sebocyte line. During IGF-1-induced lipogenesis, the level of the TFG protein was increased in a time- and dose-dependent manner. When TFG was over-expressed using recombinant adenovirus, lipid production in sebocytes was increased along with an up-regulation of the expression of lipogenic regulators, such as PPAR-γ, SREBP-1 and SCD. Conversely, down-regulation of TFG using a microRNA (miR) decreased lipid production and the expression of lipogenic regulators. Based on these data, TFG is a novel regulator of lipid synthesis in sebocytes.
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Affiliation(s)
- So-Ra Choi
- Department of Medical Science, School of Medicine, Chungnam National University, Daejeon, Korea.,Department of Dermatology, School of Medicine, Chungnam National University, Daejeon, Korea
| | - Yul-Lye Hwang
- Department of Dermatology, School of Medicine, Chungnam National University, Daejeon, Korea
| | - Soo Jung Kim
- Department of Dermatology, School of Medicine, Chungnam National University, Daejeon, Korea
| | - Kyung-Cheol Sohn
- Department of Dermatology, School of Medicine, Chungnam National University, Daejeon, Korea
| | - Chong Won Choi
- Department of Dermatology, School of Medicine, Chungnam National University, Daejeon, Korea
| | - Kyung Duck Park
- Department of Dermatology, School of Medicine, Chungnam National University, Daejeon, Korea
| | - Young Lee
- Department of Medical Science, School of Medicine, Chungnam National University, Daejeon, Korea.,Department of Dermatology, School of Medicine, Chungnam National University, Daejeon, Korea
| | - Young-Joon Seo
- Department of Medical Science, School of Medicine, Chungnam National University, Daejeon, Korea.,Department of Dermatology, School of Medicine, Chungnam National University, Daejeon, Korea
| | - Jeung-Hoon Lee
- Department of Medical Science, School of Medicine, Chungnam National University, Daejeon, Korea.,Department of Dermatology, School of Medicine, Chungnam National University, Daejeon, Korea
| | - Seung-Phil Hong
- Department of Dermatology, Dankook University College of Medicine, Cheonan, Korea
| | - Seong Jun Seo
- Department of Dermatology, Chung-Ang University College of Medicine, Seoul, Korea
| | - Seong-Jin Kim
- Department of Dermatology, Chonnam National University Medical School, Gwangju, Korea
| | - Chang Deok Kim
- Department of Medical Science, School of Medicine, Chungnam National University, Daejeon, Korea. .,Department of Dermatology, School of Medicine, Chungnam National University, Daejeon, Korea.
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27
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Su L, Zhou L, Chen FJ, Wang H, Qian H, Sheng Y, Zhu Y, Yu H, Gong X, Cai L, Yang X, Xu L, Zhao TJ, Li JZ, Chen XW, Li P. Cideb controls sterol-regulated ER export of SREBP/SCAP by promoting cargo loading at ER exit sites. EMBO J 2019; 38:embj.2018100156. [PMID: 30858281 PMCID: PMC6463267 DOI: 10.15252/embj.2018100156] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Revised: 12/21/2018] [Accepted: 01/25/2019] [Indexed: 12/30/2022] Open
Abstract
SREBPs are master regulators of lipid homeostasis and undergo sterol‐regulated export from ER to Golgi apparatus for processing and activation via COPII‐coated vesicles. While COPII recognizes SREBP through its escort protein SCAP, factor(s) specifically promoting SREBP/SCAP loading to the COPII machinery remains unknown. Here, we show that the ER/lipid droplet‐associated protein Cideb selectively promotes the loading of SREBP/SCAP into COPII vesicles. Sterol deprivation releases SCAP from Insig and enhances ER export of SREBP/SCAP by inducing SCAP‐Cideb interaction, thereby modulating sterol sensitivity. Moreover, Cideb binds to the guanine nucleotide exchange factor Sec12 to enrich SCAP/SREBP at ER exit sites, where assembling of COPII complex initiates. Loss of Cideb inhibits the cargo loading of SREBP/SCAP, reduces SREBP activation, and alleviates diet‐induced hepatic steatosis. Our data point to a linchpin role of Cideb in regulated ER export of SREBP and lipid homeostasis.
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Affiliation(s)
- Lu Su
- State Key Laboratory of Membrane Biology and Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Linkang Zhou
- State Key Laboratory of Membrane Biology and Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Feng-Jung Chen
- State Key Laboratory of Membrane Biology and Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Huimin Wang
- State Key Laboratory of Membrane Biology, Center for Life Sciences, Institute of Molecular Medicine, Peking University, Beijing, China
| | - Hui Qian
- State Key Laboratory of Membrane Biology and Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Yuanyuan Sheng
- State Key Laboratory of Membrane Biology and Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Yuangang Zhu
- State Key Laboratory of Membrane Biology, Center for Life Sciences, Institute of Molecular Medicine, Peking University, Beijing, China
| | - Hua Yu
- The First Affiliated Hospital and Center for Stem Cell and Regenerative Medicine, Department of Basic Medical Sciences, School of Medicine, Institute of Hematology, Zhejiang University, Hangzhou, Zhejiang, China
| | - Xinqi Gong
- Mathematical Intelligence Application Lab, Institute for Mathematical Sciences, Renmin University of China, Beijing, China
| | - Li'e Cai
- Key Laboratory of Rare Metabolic Disease, The Key Laboratory of Human Functional Genomics of Jiangsu Province, Nanjing Medical University, Nanjing, Jiangsu, China.,Department of Molecular Biology and Biochemistry, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Xuerui Yang
- MOE Key Laboratory of Bioinformatics, Center for Synthetic & Systems Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Li Xu
- State Key Laboratory of Membrane Biology and Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Tong-Jin Zhao
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, Fujian, China
| | - John Zhong Li
- Key Laboratory of Rare Metabolic Disease, The Key Laboratory of Human Functional Genomics of Jiangsu Province, Nanjing Medical University, Nanjing, Jiangsu, China.,Department of Molecular Biology and Biochemistry, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Xiao-Wei Chen
- State Key Laboratory of Membrane Biology, Center for Life Sciences, Institute of Molecular Medicine, Peking University, Beijing, China
| | - Peng Li
- State Key Laboratory of Membrane Biology and Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
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28
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Müller GA. The release of glycosylphosphatidylinositol-anchored proteins from the cell surface. Arch Biochem Biophys 2018; 656:1-18. [DOI: 10.1016/j.abb.2018.08.009] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Revised: 08/07/2018] [Accepted: 08/14/2018] [Indexed: 12/15/2022]
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29
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Intracellular and Plasma Membrane Events in Cholesterol Transport and Homeostasis. J Lipids 2018; 2018:3965054. [PMID: 30174957 PMCID: PMC6106919 DOI: 10.1155/2018/3965054] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Accepted: 07/26/2018] [Indexed: 12/13/2022] Open
Abstract
Cholesterol transport between intracellular compartments proceeds by both energy- and non-energy-dependent processes. Energy-dependent vesicular traffic partly contributes to cholesterol flux between endoplasmic reticulum, plasma membrane, and endocytic vesicles. Membrane contact sites and lipid transfer proteins are involved in nonvesicular lipid traffic. Only “active" cholesterol molecules outside of cholesterol-rich regions and partially exposed in water phase are able to fast transfer. The dissociation of partially exposed cholesterol molecules in water determines the rate of passive aqueous diffusion of cholesterol out of plasma membrane. ATP hydrolysis with concomitant conformational transition is required to cholesterol efflux by ABCA1 and ABCG1 transporters. Besides, scavenger receptor SR-B1 is involved also in cholesterol efflux by facilitated diffusion via hydrophobic tunnel within the molecule. Direct interaction of ABCA1 with apolipoprotein A-I (apoA-I) or apoA-I binding to high capacity binding sites in plasma membrane is important in cholesterol escape to free apoA-I. ABCG1-mediated efflux to fully lipidated apoA-I within high density lipoprotein particle proceeds more likely through the increase of “active” cholesterol level. Putative cholesterol-binding linear motifs within the structure of all three proteins ABCA1, ABCG1, and SR-B1 are suggested to contribute to the binding and transfer of cholesterol molecules from cytoplasmic to outer leaflets of lipid bilayer. Together, plasma membrane events and intracellular cholesterol metabolism and traffic determine the capacity of the cell for cholesterol efflux.
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30
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Kuscuoglu D, Janciauskiene S, Hamesch K, Haybaeck J, Trautwein C, Strnad P. Liver - master and servant of serum proteome. J Hepatol 2018; 69:512-524. [PMID: 29709680 DOI: 10.1016/j.jhep.2018.04.018] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Revised: 04/13/2018] [Accepted: 04/16/2018] [Indexed: 12/20/2022]
Abstract
Hepatocytes synthesise the majority of serum proteins. This production occurs in the endoplasmic reticulum (ER) and is adjusted by complex local and systemic regulatory mechanisms. Accordingly, serum levels of hepatocyte-made proteins constitute important biomarkers that reflect both systemic processes and the status of the liver. For example, C-reactive protein is an established marker of inflammatory reaction, whereas transferrin emerges as a liver stress marker and an attractive mortality predictor. The high protein flow through the ER poses a continuous challenge that is handled by a complex proteostatic network consisting of ER folding machinery, ER stress response, ER-associated degradation and autophagy. Various disorders disrupt this delicate balance and result in protein accumulation in the ER. These include chronic hepatitis B infection with overproduction of hepatitis B surface antigen or inherited alpha1-antitrypsin deficiency that give rise to ground glass hepatocytes and alpha1-antitrypsin aggregates, respectively. We review these ER storage disorders and their downstream consequences. The interaction between proteotoxic stress and other ER challenges such as lipotoxicity is also discussed. Collectively, this article aims to sharpen our view of liver hepatocytes as the central hubs of protein metabolism.
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Affiliation(s)
- Deniz Kuscuoglu
- Medical Clinic III, Gastroenterology, Metabolic Diseases and Intensive Care, University Hospital RWTH Aachen, Aachen, Germany; The Interdisciplinary Center for Clinical Research (IZKF), University Hospital Aachen, Aachen, Germany
| | - Sabina Janciauskiene
- Department of Respiratory Medicine, Hannover Medical School, BREATH, German Center for Lung Research (DZL), Hannover, Germany
| | - Karim Hamesch
- Medical Clinic III, Gastroenterology, Metabolic Diseases and Intensive Care, University Hospital RWTH Aachen, Aachen, Germany
| | - Johannes Haybaeck
- Institute of Pathology, Medical University Graz, Graz, Austria; Department of Pathology, Medical Faculty, Otto-von-Guericke University of Magdeburg, Magdeburg, Germany
| | - Christian Trautwein
- Medical Clinic III, Gastroenterology, Metabolic Diseases and Intensive Care, University Hospital RWTH Aachen, Aachen, Germany
| | - Pavel Strnad
- Medical Clinic III, Gastroenterology, Metabolic Diseases and Intensive Care, University Hospital RWTH Aachen, Aachen, Germany; The Interdisciplinary Center for Clinical Research (IZKF), University Hospital Aachen, Aachen, Germany.
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31
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Geva Y, Crissman J, Arakel EC, Gómez-Navarro N, Chuartzman SG, Stahmer KR, Schwappach B, Miller EA, Schuldiner M. Two novel effectors of trafficking and maturation of the yeast plasma membrane H + -ATPase. Traffic 2017; 18:672-682. [PMID: 28727280 PMCID: PMC5607100 DOI: 10.1111/tra.12503] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Revised: 07/17/2017] [Accepted: 07/17/2017] [Indexed: 11/28/2022]
Abstract
The endoplasmic reticulum (ER) is the entry site of proteins into the endomembrane system. Proteins exit the ER via coat protein II (COPII) vesicles in a selective manner, mediated either by direct interaction with the COPII coat or aided by cargo receptors. Despite the fundamental role of such receptors in protein sorting, only a few have been identified. To further define the machinery that packages secretory cargo and targets proteins from the ER to Golgi membranes, we used multiple systematic approaches, which revealed 2 uncharacterized proteins that mediate the trafficking and maturation of Pma1, the essential yeast plasma membrane proton ATPase. Ydl121c (Exp1) is an ER protein that binds Pma1, is packaged into COPII vesicles, and whose deletion causes ER retention of Pma1. Ykl077w (Psg1) physically interacts with Exp1 and can be found in the Golgi and coat protein I (COPI) vesicles but does not directly bind Pma1. Loss of Psg1 causes enhanced degradation of Pma1 in the vacuole. Our findings suggest that Exp1 is a Pma1 cargo receptor and that Psg1 aids Pma1 maturation in the Golgi or affects its retrieval. More generally our work shows the utility of high content screens in the identification of novel trafficking components.
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Affiliation(s)
- Yosef Geva
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Jonathan Crissman
- Department of Biological Sciences, Columbia University, New York, NY
| | - Eric C Arakel
- Department of Molecular Biology, Universitätsmedizin Göttingen, Göttingen, Germany
| | | | - Silvia G Chuartzman
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Kyle R Stahmer
- Department of Biological Sciences, Columbia University, New York, NY
| | - Blanche Schwappach
- Department of Molecular Biology, Universitätsmedizin Göttingen, Göttingen, Germany
| | - Elizabeth A Miller
- Department of Biological Sciences, Columbia University, New York, NY.,MRC Laboratory of Molecular Biology, Cell Biology Division, Cambridge, UK
| | - Maya Schuldiner
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
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32
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Joshi AS, Zhang H, Prinz WA. Organelle biogenesis in the endoplasmic reticulum. Nat Cell Biol 2017; 19:876-882. [DOI: 10.1038/ncb3579] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2017] [Accepted: 06/21/2017] [Indexed: 12/16/2022]
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33
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Yamaji T, Horie A, Tachida Y, Sakuma C, Suzuki Y, Kushi Y, Hanada K. Role of Intracellular Lipid Logistics in the Preferential Usage of Very Long Chain-Ceramides in Glucosylceramide. Int J Mol Sci 2016; 17:ijms17101761. [PMID: 27775668 PMCID: PMC5085785 DOI: 10.3390/ijms17101761] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Revised: 10/11/2016] [Accepted: 10/14/2016] [Indexed: 11/16/2022] Open
Abstract
Ceramide is a common precursor of sphingomyelin (SM) and glycosphingolipids (GSLs) in mammalian cells. Ceramide synthase 2 (CERS2), one of the six ceramide synthase isoforms, is responsible for the synthesis of very long chain fatty acid (C20–26 fatty acids) (VLC)-containing ceramides (VLC-Cer). It is known that the proportion of VLC species in GSLs is higher than that in SM. To address the mechanism of the VLC-preference of GSLs, we used genome editing to establish three HeLa cell mutants that expressed different amounts of CERS2 and compared the acyl chain lengths of SM and GSLs by metabolic labeling experiments. VLC-sphingolipid expression was increased along with that of CERS2, and the proportion of VLC species in glucosylceramide (GlcCer) was higher than that in SM for all expression levels of CERS2. This higher proportion was still maintained even when the proportion of C16-Cer to the total ceramides was increased by disrupting the ceramide transport protein (CERT)-dependent C16-Cer delivery pathway for SM synthesis. On the other hand, merging the Golgi apparatus and the endoplasmic reticulum (ER) by Brefeldin A decreased the proportion of VLC species in GlcCer probably due to higher accessibility of UDP-glucose ceramide glucosyltransferase (UGCG) to C16-rich ceramides. These results suggest the existence of a yet-to-be-identified mechanism rendering VLC-Cer more accessible than C16-Cer to UGCG, which is independent of CERT.
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Affiliation(s)
- Toshiyuki Yamaji
- Department of Biochemistry and Cell Biology, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo 162-8640, Japan.
| | - Aya Horie
- Department of Biochemistry and Cell Biology, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo 162-8640, Japan.
- Department of Materials and Applied Chemistry, College of Science and Technology, Nihon University, Chiyoda-ku, Tokyo 101-8308, Japan.
| | - Yuriko Tachida
- Department of Biochemistry and Cell Biology, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo 162-8640, Japan.
| | - Chisato Sakuma
- Department of Biochemistry and Cell Biology, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo 162-8640, Japan.
| | - Yusuke Suzuki
- Department of Materials and Applied Chemistry, College of Science and Technology, Nihon University, Chiyoda-ku, Tokyo 101-8308, Japan.
| | - Yasunori Kushi
- Department of Materials and Applied Chemistry, College of Science and Technology, Nihon University, Chiyoda-ku, Tokyo 101-8308, Japan.
| | - Kentaro Hanada
- Department of Biochemistry and Cell Biology, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo 162-8640, Japan.
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Tong J, Manik MK, Yang H, Im YJ. Structural insights into nonvesicular lipid transport by the oxysterol binding protein homologue family. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1861:928-939. [DOI: 10.1016/j.bbalip.2016.01.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Revised: 12/23/2015] [Accepted: 01/14/2016] [Indexed: 10/22/2022]
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Nasrollahi-Shirazi S, Sucic S, Yang Q, Freissmuth M, Nanoff C. Comparison of the β-Adrenergic Receptor Antagonists Landiolol and Esmolol: Receptor Selectivity, Partial Agonism, and Pharmacochaperoning Actions. J Pharmacol Exp Ther 2016; 359:73-81. [PMID: 27451411 DOI: 10.1124/jpet.116.232884] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Accepted: 07/18/2016] [Indexed: 01/08/2023] Open
Abstract
Blockage of β1-adrenergic receptors is one of the most effective treatments in cardiovascular medicine. Esmolol was introduced some three decades ago as a short-acting β1-selective antagonist. Landiolol is a more recent addition. Here we compared the two compounds for their selectivity for β1-adrenergic receptors over β2-adrenergic receptors, partial agonistic activity, signaling bias, and pharmacochaperoning action by using human embryonic kidney (HEK)293 cell lines, which heterologously express each human receptor subtype. The affinity of landiolol for β1-adrenergic receptors and β2-adrenergic receptors was higher and lower than that of esmolol, respectively, resulting in an improved selectivity (216-fold versus 30-fold). The principal metabolite of landiolol (M1) was also β1-selective, but its affinity was very low. Both landiolol and esmolol caused a very modest rise in cAMP levels but a robust increase in the phosphorylation of extracellular signal regulated kinases 1 and 2, indicating that the two drugs exerted partial agonist activity with a signaling bias. If cells were incubated for ≥24 hours in the presence of ≥1 μM esmolol, the levels of β1-adrenergic-but not of β2-adrenergic-receptors increased. This effect was contingent on export of the β1-receptor from endoplasmic reticulum and was not seen in the presence of landiolol. On the basis of these observations, we conclude that landiolol offers the advantage of: 1) improved selectivity and 2) the absence of pharmacochaperoning activity, which sensitizes cells to rebound effects upon drug discontinuation.
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Affiliation(s)
- Shahrooz Nasrollahi-Shirazi
- Institute of Pharmacology, Center of Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Sonja Sucic
- Institute of Pharmacology, Center of Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Qiong Yang
- Institute of Pharmacology, Center of Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Michael Freissmuth
- Institute of Pharmacology, Center of Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Christian Nanoff
- Institute of Pharmacology, Center of Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
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Wang Y, Liu L, Zhang H, Fan J, Zhang F, Yu M, Shi L, Yang L, Lam SM, Wang H, Chen X, Wang Y, Gao F, Shui G, Xu Z. Mea6 controls VLDL transport through the coordinated regulation of COPII assembly. Cell Res 2016; 26:787-804. [PMID: 27311593 DOI: 10.1038/cr.2016.75] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Revised: 05/02/2016] [Accepted: 05/09/2016] [Indexed: 12/16/2022] Open
Abstract
Lipid accumulation, which may be caused by the disturbance in very low density lipoprotein (VLDL) secretion in the liver, can lead to fatty liver disease. VLDL is synthesized in endoplasmic reticulum (ER) and transported to Golgi apparatus for secretion into plasma. However, the underlying molecular mechanism for VLDL transport is still poorly understood. Here we show that hepatocyte-specific deletion of meningioma-expressed antigen 6 (Mea6)/cutaneous T cell lymphoma-associated antigen 5C (cTAGE5C) leads to severe fatty liver and hypolipemia in mice. Quantitative lipidomic and proteomic analyses indicate that Mea6/cTAGE5 deletion impairs the secretion of different types of lipids and proteins, including VLDL, from the liver. Moreover, we demonstrate that Mea6/cTAGE5 interacts with components of the ER coat protein complex II (COPII) which, when depleted, also cause lipid accumulation in hepatocytes. Our findings not only reveal several novel factors that regulate lipid transport, but also provide evidence that Mea6 plays a critical role in lipid transportation through the coordinated regulation of the COPII machinery.
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Affiliation(s)
- Yaqing Wang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Liang Liu
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China.,University of Chinese Academy of Sciences, Beijing 100101, China
| | - Hongsheng Zhang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China.,University of Chinese Academy of Sciences, Beijing 100101, China
| | - Junwan Fan
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China.,University of Chinese Academy of Sciences, Beijing 100101, China
| | - Feng Zhang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China.,University of Chinese Academy of Sciences, Beijing 100101, China
| | - Mei Yu
- School of Life Science, Shandong University, Jinan 250100, China
| | - Lei Shi
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Lin Yang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Sin Man Lam
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Huimin Wang
- Institute of Molecular Medicine, Peking University, Beijing 100871, China
| | - Xiaowei Chen
- Institute of Molecular Medicine, Peking University, Beijing 100871, China
| | - Yingchun Wang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Fei Gao
- State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
| | - Guanghou Shui
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Zhiheng Xu
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China.,Translational Medical Center for Stem Cell Therapy, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China
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Ferru-Clément R, Spanova M, Dhayal S, Morgan NG, Hélye R, Becq F, Hirose H, Antonny B, Vamparys L, Fuchs PFJ, Ferreira T. Targeting surface voids to counter membrane disorders in lipointoxication-related diseases. J Cell Sci 2016; 129:2368-81. [PMID: 27142833 DOI: 10.1242/jcs.183590] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Accepted: 04/26/2016] [Indexed: 01/01/2023] Open
Abstract
Saturated fatty acids (SFA), which are abundant in the so-called western diet, have been shown to efficiently incorporate within membrane phospholipids and therefore impact on organelle integrity and function in many cell types. In the present study, we have developed a yeast-based two-step assay and a virtual screening strategy to identify new drugs able to counter SFA-mediated lipointoxication. The compounds identified here were effective in relieving lipointoxication in mammalian β-cells, one of the main targets of SFA toxicity in humans. In vitro reconstitutions and molecular dynamics simulations on bilayers revealed that these molecules, albeit according to different mechanisms, can generate voids at the membrane surface. The resulting surface defects correlate with the recruitment of loose lipid packing or void-sensing proteins required for vesicular budding, a central cellular process that is precluded under SFA accumulation. Taken together, the results presented here point at modulation of surface voids as a central parameter to consider in order to counter the impacts of SFA on cell function.
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Affiliation(s)
- Romain Ferru-Clément
- Laboratoire Signalisation et Transports Ioniques Membranaires (STIM), CNRS ERL 7368, Université de Poitiers, 1, rue Georges Bonnet, Poitiers Cedex 9 86073, France Société d'Accélération du Transfert de Technologie (SATT) Grand Centre, 8 rue Pablo Picasso, Clermont-Ferrand 63000, France
| | - Miroslava Spanova
- Laboratoire Signalisation et Transports Ioniques Membranaires (STIM), CNRS ERL 7368, Université de Poitiers, 1, rue Georges Bonnet, Poitiers Cedex 9 86073, France
| | - Shalinee Dhayal
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter EX2 5DW, UK
| | - Noel G Morgan
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter EX2 5DW, UK
| | - Reynald Hélye
- Société d'Accélération du Transfert de Technologie (SATT) Grand Centre, 8 rue Pablo Picasso, Clermont-Ferrand 63000, France
| | - Frédéric Becq
- Laboratoire Signalisation et Transports Ioniques Membranaires (STIM), CNRS ERL 7368, Université de Poitiers, 1, rue Georges Bonnet, Poitiers Cedex 9 86073, France
| | - Hisaaki Hirose
- Institut de Pharmacologie Moléculaire et Cellulaire, CNRS UMR 7275, Université de Nice Sofia-Antipolis, 660 route des Lucioles, Valbonne 06560, France
| | - Bruno Antonny
- Institut de Pharmacologie Moléculaire et Cellulaire, CNRS UMR 7275, Université de Nice Sofia-Antipolis, 660 route des Lucioles, Valbonne 06560, France
| | - Lydie Vamparys
- Dynamique des membranes et trafic intracellulaire, Institut Jacques Monod, CNRS UMR 7592, Université Paris Diderot, Sorbonne Paris Cité, 15 rue Hélène Brion, Paris 75013, France
| | - Patrick F J Fuchs
- Dynamique des membranes et trafic intracellulaire, Institut Jacques Monod, CNRS UMR 7592, Université Paris Diderot, Sorbonne Paris Cité, 15 rue Hélène Brion, Paris 75013, France
| | - Thierry Ferreira
- Laboratoire Signalisation et Transports Ioniques Membranaires (STIM), CNRS ERL 7368, Université de Poitiers, 1, rue Georges Bonnet, Poitiers Cedex 9 86073, France
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Tiwari S, Siddiqi S, Zhelyabovska O, Siddiqi SA. Silencing of Small Valosin-containing Protein-interacting Protein (SVIP) Reduces Very Low Density Lipoprotein (VLDL) Secretion from Rat Hepatocytes by Disrupting Its Endoplasmic Reticulum (ER)-to-Golgi Trafficking. J Biol Chem 2016; 291:12514-12526. [PMID: 27129256 DOI: 10.1074/jbc.m115.705269] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Indexed: 01/07/2023] Open
Abstract
The transport of nascent very low density lipoprotein (VLDL) particles from the endoplasmic reticulum (ER) to the Golgi determines their secretion by the liver and is mediated by a specialized ER-derived vesicle, the VLDL transport vesicle (VTV). Our previous studies have shown that the formation of ER-derived VTV requires proteins in addition to coat complex II proteins. The VTV proteome revealed that a 9-kDa protein, small valosin-containing protein-interacting protein (SVIP), is uniquely present in these specialized vesicles. Our biochemical and morphological data indicate that the VTV contains SVIP. Using confocal microscopy and co-immunoprecipitation assays, we show that SVIP co-localizes with apolipoprotein B-100 (apoB100) and specifically interacts with VLDL apoB100 and coat complex II proteins. Treatment of ER membranes with myristic acid in the presence of cytosol increases SVIP recruitment to the ER in a concentration-dependent manner. Furthermore, we show that myristic acid treatment of hepatocytes increases both VTV budding and VLDL secretion. To determine the role of SVIP in VTV formation, we either blocked the SVIP protein using specific antibodies or silenced SVIP by siRNA in hepatocytes. Our results show that both blocking and silencing of SVIP lead to significant reduction in VTV formation. Additionally, we show that silencing of SVIP reduces VLDL secretion, suggesting a physiological role of SVIP in intracellular VLDL trafficking and secretion. We conclude that SVIP acts as a novel regulator of VTV formation by interacting with its cargo and coat proteins and has significant implications in VLDL secretion by hepatocytes.
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Affiliation(s)
- Samata Tiwari
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, Florida 32827
| | - Shaila Siddiqi
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, Florida 32827
| | - Olga Zhelyabovska
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, Florida 32827
| | - Shadab A Siddiqi
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, Florida 32827.
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Merched AJ, Daret D, Li L, Franzl N, Sauvage-Merched M. Specific autoantigens in experimental autoimmunity-associated atherosclerosis. FASEB J 2016; 30:2123-34. [PMID: 26891734 DOI: 10.1096/fj.201500131] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2015] [Accepted: 02/01/2016] [Indexed: 12/22/2022]
Abstract
Higher cardiovascular morbidity in patients with a wide range of autoimmune diseases highlights the importance of autoimmunity in promoting atherosclerosis. Our purpose was to investigate the mechanisms of accelerated atherosclerosis and identified vascular autoantigens targeted by autoimmunity. We created a mouse model of autoimmunity-associated atherosclerosis by transplanting bone marrow from FcγRIIB knockout (FcRIIB(-/-)) mice into LDL receptor knockout mice. We characterized the cellular and molecular mechanisms of atherogenesis and identified specific aortic autoantigens using serologic proteomic studies. En face lesion area analysis showed more aggressive atherosclerosis in autoimmune mice compared with control mice (0.64 ± 0.12 vs 0.32 ± 0.05 mm(2); P < 0.05, respectively). At the cellular level, FcRIIB(-/-) macrophages showed significant reduction (46-72%) in phagocytic capabilities. Proteomic analysis revealed circulating autoantibodies in autoimmune mice that targeted 25 atherosclerotic lesion proteins, including essential components of adhesion complex, cytoskeleton, and extracellular matrix, and proteins involved in critical functions and pathways. Microscopic examination of atherosclerotic plaques revealed essential colocalization of autoantibodies with endothelial cells, their adherence to basement membranes, the internal elastica lamina, and necrotic cores. The new vascular autoimmunosome may be a useful target for diagnostic and immunotherapeutic interventions in autoimmunity-associated diseases that have accelerated atherosclerosis.-Merched, A. J., Daret, D., Li, L., Franzl, N., Sauvage-Merched, M. Specific autoantigens in experimental autoimmunity-associated atherosclerosis.
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Affiliation(s)
- Aksam J Merched
- Department of Pharmaceutical Sciences, and INSERM U1053, University of Bordeaux, Bordeaux, France Department of Cell Biology, Baylor College of Medicine, Houston, Texas, USA
| | - Danièle Daret
- Department of Cell Biology, Baylor College of Medicine, Houston, Texas, USA
| | - Lan Li
- Department of Cell Biology, Baylor College of Medicine, Houston, Texas, USA
| | - Nathalie Franzl
- Department of Cell Biology, Baylor College of Medicine, Houston, Texas, USA
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Olson DK, Fröhlich F, Farese RV, Walther TC. Taming the sphinx: Mechanisms of cellular sphingolipid homeostasis. Biochim Biophys Acta Mol Cell Biol Lipids 2015; 1861:784-792. [PMID: 26747648 DOI: 10.1016/j.bbalip.2015.12.021] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Revised: 12/14/2015] [Accepted: 12/28/2015] [Indexed: 12/11/2022]
Abstract
Sphingolipids are important structural membrane components of eukaryotic cells, and potent signaling molecules. As such, their levels must be maintained to optimize cellular functions in different cellular membranes. Here, we review the current knowledge of homeostatic sphingolipid regulation. We describe recent studies in Saccharomyces cerevisiae that have provided insights into how cells sense changes in sphingolipid levels in the plasma membrane and acutely regulate sphingolipid biosynthesis by altering signaling pathways. We also discuss how cellular trafficking has emerged as an important determinant of sphingolipid homeostasis. Finally, we highlight areas where work is still needed to elucidate the mechanisms of sphingolipid regulation and the physiological functions of such regulatory networks, especially in mammalian cells. This article is part of a Special Issue entitled: The cellular lipid landscape edited by Tim P. Levine and Anant K. Menon.
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Affiliation(s)
- D K Olson
- Department of Genetics and Complex Diseases, Harvard T. H. Chan School of Public Health, United States; Department of Cell Biology, Yale School of Medicine, United States
| | - F Fröhlich
- Department of Genetics and Complex Diseases, Harvard T. H. Chan School of Public Health, United States
| | - R V Farese
- Department of Genetics and Complex Diseases, Harvard T. H. Chan School of Public Health, United States; Department of Cell Biology, Harvard Medical School, United States; Broad Institute of Harvard and MIT, United States.
| | - T C Walther
- Department of Genetics and Complex Diseases, Harvard T. H. Chan School of Public Health, United States; Department of Cell Biology, Harvard Medical School, United States; Broad Institute of Harvard and MIT, United States; Howard Hughes Medical Institute, United States.
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Ghanem E, Al-Balushi M. Adopting the rapamycin trapping assay to track the trafficking of murine MHC class I alleles, H-2K(b). BMC Cell Biol 2015; 16:30. [PMID: 26714929 PMCID: PMC4696223 DOI: 10.1186/s12860-015-0077-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Accepted: 12/14/2015] [Indexed: 11/22/2022] Open
Abstract
Background In mammalian cells, the quality control (QC) of properly folded proteins is monitored in the early secretory pathway, particularly in the endoplasmic reticulum (ER). Several proteins, including our protein of interest, major histocompatibility complex class I (MHC class I), can bypass the first line of ER-QC and reside in post-ER compartments in an unfolded form. Such forms entail both monomeric and dimeric structures that are devoid of peptides and thus cannot fulfill the immunological function of antigen presentation at the cell surface. MHC class I structures become mature and properly folded once loaded with the appropriate peptides in the framework of the peptide loading complex (PLC). Despite the flood of information on the diverse trafficking behavior of different MHC class I alleles, there is still controversy on the actual trajectory followed by improperly folded murine MHC class I alleles, namely H-2Kb. In this study, we employ an in vitro rapamycin trapping assay, live cell imaging, and a biochemical COPII budding approach to further investigate the trafficking of H-2Kb beyond the level of the ER. Results We confirm the egress of H-2Kb in an unfolded form to a post-ER compartment from where they can cycle back to the ER. Deciphering the exact identity of the post-ER compartment by laser scanning microscopy did not only point to the existence of the ERGIC and cis-Golgi compartments as residency areas for unfolded proteins, but also to the involvement of an addional compartment, that lies in close proximity and possesses high resemblance to the aforementioned compartments. Interestingly, we were capable of showing using the same rapamycin trapping assay that H-2Kb can undergo a potential maturation event during their cycling; this is attained upon addition of peptides and trapping of accumulated post-ER molecules at the cell surface. Conclusions Our findings deepen the understanding of H-2Kb trafficking outside the ER and pave the way to decipher the role and the trafficking of certain PLC chaperones, such as tapasin, throughout H-2Kb post-ER QC. Finally, we demonstrate the plausible usage of the rapamycin assay to assess the trafficking of defected proteins especially in diseases and under therapeutic studies.
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Affiliation(s)
- Esther Ghanem
- Department of Biology, Faculty of Natural and Applied Sciences, Notre Dame University, 72, Zouk Mosbeh, Keserwan district, Lebanon.
| | - Mohammed Al-Balushi
- Department of Microbiology and Immunology, Sultan Qaboos University, Muscat, Oman.
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Characterization of VAMP2 in Schistosoma japonicum and the Evaluation of Protective Efficacy Induced by Recombinant SjVAMP2 in Mice. PLoS One 2015; 10:e0144584. [PMID: 26641090 PMCID: PMC4671580 DOI: 10.1371/journal.pone.0144584] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2015] [Accepted: 11/20/2015] [Indexed: 11/25/2022] Open
Abstract
Background The outer-tegument membrane covering the schistosome is believed to maintain via the fusion of membranous vesicles. Fusion of biological membranes is a fundamental process in all eukaryotic cells driven by formation of trans-SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) complexes through pairing of vesicle associated v-SNAREs (VAMP) with complementary t-SNAREs on target membranes. The purpose of this study was to characterize Schistosoma japonicum vesicle-associated membrane protein 2 (SjVAMP2) and to investigate its potential as a candidate vaccine against schistosomiasis. Methodology/Principal Findings The sequence of SjVAMP2 was analyzed, cloned, expressed and characterized. SjVAMP2 is a member of the synaptobrevin superfamily harboring the v-SNARE coiled-coil homology domain. RT–PCR analysis revealed that significantly higher SjVAMP2 levels were observed in 14-, 28- and 42-day-old worms, and SjVAMP2 expression was much higher in 42-day-old female worms than in those male worms. Additionally, the expression of SjVAMP2 was associated with membrane recovery in PZQ-treated worms. Immunostaining assay showed that SjVAMP2 was mainly distributed in the sub-tegument of the worms. Western blotting revealed that rSjVAMP2 showed strong immunogenicity. Purified rSjVAMP2 emulsified with ISA206 adjuvant induced 41.5% and 27.3% reductions in worm burden, and 36.8% and 23.3% reductions in hepatic eggs in two independent trials. Besides, significantly higher rSjVAMP2-specific IgG, IgG1, IgG2a levels were detected in rSjVAMP2-vaccinated mice. Conclusion Our study indicated that SjVAMP2 is a potential vaccine candidate against S. japonicum and provided the basis for further investigations into the biological function of SjVAMP2.
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Sphingosine Kinase 2 and Ceramide Transport as Key Targets of the Natural Flavonoid Luteolin to Induce Apoptosis in Colon Cancer Cells. PLoS One 2015; 10:e0143384. [PMID: 26580959 PMCID: PMC4651545 DOI: 10.1371/journal.pone.0143384] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Accepted: 11/04/2015] [Indexed: 01/26/2023] Open
Abstract
The plant flavonoid luteolin exhibits different biological effects, including anticancer properties. Little is known on the molecular mechanisms underlying its actions in colorectal cancer (CRC). Here we investigated the effects of luteolin on colon cancer cells, focusing on the balance between ceramide and sphingosine-1-phosphate (S1P), two sphingoid mediators with opposite roles on cell fate. Using cultured cells, we found that physiological concentrations of luteolin induce the elevation of ceramide, followed by apoptotic death of colon cancer cells, but not of differentiated enterocytes. Pulse studies revealed that luteolin inhibits ceramide anabolism to complex sphingolipids. Further experiments led us to demonstrate that luteolin induces an alteration of the endoplasmic reticulum (ER)-Golgi flow of ceramide, pivotal to its metabolic processing to complex sphingolipids. We report that luteolin exerts its action by inhibiting both Akt activation, and sphingosine kinase (SphK) 2, with the consequent reduction of S1P, an Akt stimulator. S1P administration protected colon cancer cells from luteolin-induced apoptosis, most likely by an intracellular, receptor-independent mechanism. Overall this study reveals for the first time that the dietary flavonoid luteolin exerts toxic effects on colon cancer cells by inhibiting both S1P biosynthesis and ceramide traffic, suggesting its dietary introduction/supplementation as a potential strategy to improve existing treatments in CRC.
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Pieri L, Chafey P, Le Gall M, Clary G, Melki R, Redeker V. Cellular response of human neuroblastoma cells to α-synuclein fibrils, the main constituent of Lewy bodies. Biochim Biophys Acta Gen Subj 2015; 1860:8-19. [PMID: 26468903 DOI: 10.1016/j.bbagen.2015.10.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Revised: 09/14/2015] [Accepted: 10/08/2015] [Indexed: 11/17/2022]
Abstract
BACKGROUND α-Synuclein (α-Syn) fibrils are the main constituent of Lewy bodies and a neuropathological hallmark of Parkinson's disease (PD). The propagation of α-Syn assemblies from cell to cell suggests that they are involved in PD progression. We previously showed that α-Syn fibrils are toxic because of their ability to bind and permeabilize cell membranes. Here, we document the cellular response in terms of proteome changes of SH-SY5Y cells exposed to exogenous α-Syn fibrils. METHODS We compare the proteomes of cells of neuronal origin exposed or not either to oligomeric or fibrillar α-Syn using two dimensional differential in-gel electrophoresis (2D-DIGE) and mass spectrometry. RESULTS Only α-Syn fibrils induce significant changes in the proteome of SH-SY5Y cells. In addition to proteins associated to apoptosis and toxicity, or proteins previously linked to neurodegenerative diseases, we report an overexpression of proteins involved in intracellular vesicle trafficking. We also report a remarkable increase in fibrillar α-Syn heterogeneity, mainly due to C-terminal truncations. CONCLUSIONS Our results show that cells of neuronal origin adapt their proteome to exogenous α-Syn fibrils and actively modify those assemblies. GENERAL SIGNIFICANCE Cells of neuronal origin adapt their proteome to exogenous toxic α-Syn fibrils and actively modify those assemblies. Our results bring insights into the cellular response and clearance events the cells implement to face the propagation of α-Syn assemblies associated to pathology.
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Affiliation(s)
- Laura Pieri
- Paris-Saclay Institute of Neuroscience, CNRS, Université Paris-Saclay, Avenue de la terrasse, 91190 Gif-sur-Yvette, France
| | - Philippe Chafey
- Plate-forme protéomique 3P5, Université Paris Descartes, Sorbonne Paris Cité, France; Inserm U1016, Institut Cochin, Paris, France; CNRS, UMR8104, Paris, France
| | - Morgane Le Gall
- Plate-forme protéomique 3P5, Université Paris Descartes, Sorbonne Paris Cité, France; Inserm U1016, Institut Cochin, Paris, France; CNRS, UMR8104, Paris, France
| | - Guilhem Clary
- Plate-forme protéomique 3P5, Université Paris Descartes, Sorbonne Paris Cité, France; Inserm U1016, Institut Cochin, Paris, France; CNRS, UMR8104, Paris, France
| | - Ronald Melki
- Paris-Saclay Institute of Neuroscience, CNRS, Université Paris-Saclay, Avenue de la terrasse, 91190 Gif-sur-Yvette, France
| | - Virginie Redeker
- Paris-Saclay Institute of Neuroscience, CNRS, Université Paris-Saclay, Avenue de la terrasse, 91190 Gif-sur-Yvette, France.
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Studying lipoprotein trafficking in zebrafish, the case of chylomicron retention disease. J Mol Med (Berl) 2015; 93:115-8. [PMID: 25572701 DOI: 10.1007/s00109-014-1248-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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46
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Martzoukou O, Karachaliou M, Yalelis V, Leung J, Byrne B, Amillis S, Diallinas G. Oligomerization of the UapA Purine Transporter Is Critical for ER-Exit, Plasma Membrane Localization and Turnover. J Mol Biol 2015; 427:2679-96. [DOI: 10.1016/j.jmb.2015.05.021] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Revised: 05/27/2015] [Accepted: 05/28/2015] [Indexed: 11/29/2022]
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Saito K, Katada T. Mechanisms for exporting large-sized cargoes from the endoplasmic reticulum. Cell Mol Life Sci 2015; 72:3709-20. [PMID: 26082182 PMCID: PMC4565863 DOI: 10.1007/s00018-015-1952-9] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2015] [Revised: 05/18/2015] [Accepted: 06/08/2015] [Indexed: 12/14/2022]
Abstract
Cargo proteins exported from the endoplasmic reticulum to the Golgi apparatus are typically transported in coat protein complex II (COPII)-coated vesicles of 60–90 nm diameter. Several cargo molecules including collagens and chylomicrons form structures that are too large to be accommodated by these vesicles, but their secretion still requires COPII proteins. Here, we first review recent progress on large cargo secretions derived especially from animal models and human diseases, which indicate the importance of COPII proteins. We then discuss the recent isolation of specialized factors that modulate the process of COPII-dependent cargo formation to facilitate the exit of large-sized cargoes from the endoplasmic reticulum. Based on these findings, we propose a model that describes the importance of the GTPase cycle for secretion of oversized cargoes. Next, we summarize reports that describe the structures of COPII proteins and how these results provide insight into the mechanism of assembly of the large cargo carriers. Finally, we discuss what issues remain to be solved in the future.
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Affiliation(s)
- Kota Saito
- Department of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan.
| | - Toshiaki Katada
- Department of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
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Phosphoregulatory protein 14-3-3 facilitates SAC1 transport from the endoplasmic reticulum. Proc Natl Acad Sci U S A 2015; 112:E3199-206. [PMID: 26056309 DOI: 10.1073/pnas.1509119112] [Citation(s) in RCA: 196] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Most secretory cargo proteins in eukaryotes are synthesized in the endoplasmic reticulum and actively exported in membrane-bound vesicles that are formed by the cytosolic coat protein complex II (COPII). COPII proteins are assisted by a variety of cargo-specific adaptor proteins required for the concentration and export of secretory proteins from the endoplasmic reticulum (ER). Adaptor proteins are key regulators of cargo export, and defects in their function may result in disease phenotypes in mammals. Here we report the role of 14-3-3 proteins as a cytosolic adaptor in mediating SAC1 transport in COPII-coated vesicles. Sac1 is a phosphatidyl inositol-4 phosphate (PI4P) lipid phosphatase that undergoes serum dependent translocation between the endoplasmic reticulum and Golgi complex and controls cellular PI4P lipid levels. We developed a cell-free COPII vesicle budding reaction to examine SAC1 exit from the ER that requires COPII and at least one additional cytosolic factor, the 14-3-3 protein. Recombinant 14-3-3 protein stimulates the packaging of SAC1 into COPII vesicles and the sorting subunit of COPII, Sec24, interacts with 14-3-3. We identified a minimal sorting motif of SAC1 that is important for 14-3-3 binding and which controls SAC1 export from the ER. This LS motif is part of a 7-aa stretch, RLSNTSP, which is similar to the consensus 14-3-3 binding sequence. Homology models, based on the SAC1 structure from yeast, predict this region to be in the exposed exterior of the protein. Our data suggest a model in which the 14-3-3 protein mediates SAC1 traffic from the ER through direct interaction with a sorting signal and COPII.
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49
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Hedrich R, Sauer N, Neuhaus HE. Sugar transport across the plant vacuolar membrane: nature and regulation of carrier proteins. CURRENT OPINION IN PLANT BIOLOGY 2015; 25:63-70. [PMID: 26000864 DOI: 10.1016/j.pbi.2015.04.008] [Citation(s) in RCA: 83] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Revised: 04/16/2015] [Accepted: 04/30/2015] [Indexed: 05/06/2023]
Abstract
The ability of higher plants to store sugars is of crucial importance for plant development, adaption to endogenous or environmental cues and for the economic value of crop species. Sugar storage and accumulation, and its homeostasis in plant cells are managed by the vacuole. Although transport of sugars across the vacuolar membrane has been monitored for about four decades, the molecular entities of the transporters involved have been identified in the last 10 years only. Thus, it is just recently that our pictures of the transporters that channel the sugar load across the tonoplast have gained real shape. Here we describe the molecular nature and regulation of an important group of tonoplast sugar transporter (TST) allowing accumulation of sugars against large concentration gradients. In addition, we report on proton-driven tonoplast sugar exporters and on facilitators, which are also involved in balancing cytosolic and vacuolar sugar levels.
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Affiliation(s)
- Rainer Hedrich
- Molecular Plant Physiology and Biophysics, University of Würzburg, Germany
| | - Norbert Sauer
- Molecular Plant Physiology, University of Erlangen-Nuremberg, Germany
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50
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Olson DK, Fröhlich F, Christiano R, Hannibal-Bach HK, Ejsing CS, Walther TC. Rom2-dependent phosphorylation of Elo2 controls the abundance of very long-chain fatty acids. J Biol Chem 2014; 290:4238-47. [PMID: 25519905 DOI: 10.1074/jbc.m114.629279] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Sphingolipids are essential components of eukaryotic membranes, where they serve to maintain membrane integrity. They are important components of membrane trafficking and function in signaling as messenger molecules. Sphingolipids are synthesized de novo from very long-chain fatty acids (VLCFA) and sphingoid long-chain bases, which are amide linked to form ceramide and further processed by addition of various headgroups. Little is known concerning the regulation of VLCFA levels and how cells coordinate their synthesis with the availability of long-chain bases for sphingolipid synthesis. Here we show that Elo2, a key enzyme of VLCFA synthesis, is controlled by signaling of the guanine nucleotide exchange factor Rom2, initiating at the plasma membrane. This pathway controls Elo2 phosphorylation state and VLCFA synthesis. Our data identify a regulatory mechanism for coordinating VLCFA synthesis with sphingolipid metabolism and link signal transduction pathways from the plasma membrane to the regulation of lipids for membrane homeostasis.
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Affiliation(s)
- Daniel K Olson
- From the Department of Genetics and Complex Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts 02115, the Department of Cell Biology, Yale School of Medicine, New Haven, Connecticut 06150
| | - Florian Fröhlich
- From the Department of Genetics and Complex Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts 02115
| | - Romain Christiano
- From the Department of Genetics and Complex Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts 02115
| | - Hans K Hannibal-Bach
- the Department of Biochemistry and Molecular Biology, University of Southern Denmark, 0230 Odense, Denmark
| | - Christer S Ejsing
- the Department of Biochemistry and Molecular Biology, University of Southern Denmark, 0230 Odense, Denmark
| | - Tobias C Walther
- From the Department of Genetics and Complex Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts 02115, the Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115, and the Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142
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