1
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Lu Q, Zhu Z, Zhang J, Xu C. Structure of GDP-bound Rab7 Q67L in complex with ORP1L. Biochem Biophys Res Commun 2024; 725:150232. [PMID: 38897042 DOI: 10.1016/j.bbrc.2024.150232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2024] [Accepted: 06/05/2024] [Indexed: 06/21/2024]
Abstract
Molecular processes are orchestrated by various proteins that promote early endosomes to become late endosomes and eventually fuse with lysosomes, guaranteeing the degradation of the content. Rab7, which is localized to late endosomes, is one of the most well-known GTPases. ORP1L is recruited by Rab7 to facilitate the fusion of late endosomes and lysosomes. Here, we present the structure of GDP-bound Rab7 Q67L with ORP1L. Structural analysis, supported by biochemical and ITC binding experiments, not only provides structural insight into the interactions between the ORP1L ANK domain and Rab7 but also suggests that the GTPase activity of Rab7 does not interfere with its ORP1L-binding capacity.
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Affiliation(s)
- Qian Lu
- Center for Advanced Interdisciplinary Science and Biomedicine of IHM, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230027, PR China
| | - Zhongliang Zhu
- Center for Advanced Interdisciplinary Science and Biomedicine of IHM, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230027, PR China
| | - Jiahai Zhang
- Center for Advanced Interdisciplinary Science and Biomedicine of IHM, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230027, PR China.
| | - Chao Xu
- Center for Advanced Interdisciplinary Science and Biomedicine of IHM, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230027, PR China.
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2
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Gurlo T, Liu R, Wang Z, Hoang J, Ryazantsev S, Daval M, Butler AE, Yang X, Blencowe M, Butler PC. Dysregulation of cholesterol homeostasis is an early signal of β-cell proteotoxicity characteristic of type 2 diabetes. Physiol Genomics 2024; 56:621-633. [PMID: 38949617 DOI: 10.1152/physiolgenomics.00029.2024] [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: 03/21/2024] [Revised: 06/26/2024] [Accepted: 06/27/2024] [Indexed: 07/02/2024] Open
Abstract
Type 2 diabetes (T2D) is a common metabolic disease due to insufficient insulin secretion by pancreatic β-cells in the context of insulin resistance. Islet molecular pathology reveals a role for protein misfolding in β-cell dysfunction and loss with islet amyloid derived from islet amyloid polypeptide (IAPP), a protein coexpressed and cosecreted with insulin. The most toxic form of misfolded IAPP is intracellular membrane disruptive toxic oligomers present in β-cells in T2D and in β-cells of mice transgenic for human IAPP (hIAPP). Prior work revealed a high degree of overlap of transcriptional changes in islets from T2D and prediabetic 9- to 10-wk-old mice transgenic for hIAPP with most changes being pro-survival adaptations and therefore of limited therapeutic guidance. Here, we investigated islets from hIAPP transgenic mice at an earlier age (6 wk) to screen for potential mediators of hIAPP toxicity that precede predominance of pro-survival signaling. We identified early suppression of cholesterol synthesis and trafficking along with aberrant intra-β-cell cholesterol and lipid deposits and impaired cholesterol trafficking to cell membranes. These findings align with comparable lipid deposits present in β-cells in T2D and increased vulnerability to develop T2D in individuals taking medications that suppress cholesterol synthesis.NEW & NOTEWORTHY β-Cell failure in type 2 diabetes (T2D) is characterized by β-cell misfolded protein stress due to the formation of toxic oligomers of islet amyloid polypeptide (IAPP). Most transcriptional changes in islets in T2D are pro-survival adaptations consistent with the slow progression of β-cell loss. In the present study, investigation of the islet transcriptional signatures in a mouse model of T2D expressing human IAPP revealed decreased cholesterol synthesis and trafficking as a plausible early mediator of IAPP toxicity.
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Affiliation(s)
- Tatyana Gurlo
- Larry L. Hillblom Islet Research Center, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California, United States
| | - Ruoshui Liu
- Department of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, California, United States
| | - Zhongying Wang
- Larry L. Hillblom Islet Research Center, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California, United States
| | - Jonathan Hoang
- Larry L. Hillblom Islet Research Center, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California, United States
| | - Sergey Ryazantsev
- Electron Imaging Center, California Nano Systems Institute, University of California, Los Angeles, Los Angeles, California, United States
| | - Marie Daval
- Larry L. Hillblom Islet Research Center, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California, United States
| | - Alexandra E Butler
- Larry L. Hillblom Islet Research Center, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California, United States
| | - Xia Yang
- Department of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, California, United States
- Molecular, Cellular, and Integrative Physiology Interdepartmental Program, University of California, Los Angeles, Los Angeles, California, United States
| | - Montgomery Blencowe
- Department of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, California, United States
- Molecular, Cellular, and Integrative Physiology Interdepartmental Program, University of California, Los Angeles, Los Angeles, California, United States
| | - Peter C Butler
- Larry L. Hillblom Islet Research Center, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California, United States
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3
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Han Y, Liu X, Xu L, Wei Z, Gu Y, Ren Y, Hua W, Zhang Y, Liu X, Jiang C, Zhuang R, Hong W, Wang T. RILP Induces Cholesterol Accumulation in Lysosomes by Inhibiting Endoplasmic Reticulum-Endolysosome Interactions. Cells 2024; 13:1313. [PMID: 39195203 DOI: 10.3390/cells13161313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2024] [Revised: 07/26/2024] [Accepted: 07/28/2024] [Indexed: 08/29/2024] Open
Abstract
Endoplasmic reticulum (ER)-endolysosome interactions regulate cholesterol exchange between the ER and the endolysosome. ER-endolysosome membrane contact sites mediate the ER-endolysosome interaction. VAP-ORP1L (vesicle-associated membrane protein-associated protein- OSBP-related protein 1L) interaction forms the major contact site between the ER and the lysosome, which is regulated by Rab7. RILP (Rab7-interacting lysosomal protein) is the downstream effector of Rab7, but its role in the organelle interaction between the ER and the lysosome is not clear. In this study, we found RILP interacts with ORP1L to competitively inhibit the formation of the VAP-ORP1L contact site. Immunofluorescence microscopy revealed that RILP induces late endosome/lysosome clustering, which reduces the contact of endolysosomes with the ER, interfering with the ER-endolysosome interaction. Further examination demonstrated that over-expression of RILP results in the accumulation of cholesterol in the clustered endolysosomes, which triggers cellular autophagy depending on RILP. Our results suggest that RILP interferes with the ER-endolysosome interaction to inhibit cholesterol flow from the endolysosome to the ER, which feedbacks to trigger autophagy.
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Affiliation(s)
- Yang Han
- State Key Laboratory of Cellular Stress Biology, School of Pharmaceutical Sciences, Fujian Provincial Key Laboratory of Innovative Drug Target Research, Xiamen University, Xiamen 361102, China
| | - Xiaoqing Liu
- State Key Laboratory of Cellular Stress Biology, School of Pharmaceutical Sciences, Fujian Provincial Key Laboratory of Innovative Drug Target Research, Xiamen University, Xiamen 361102, China
| | - Liju Xu
- State Key Laboratory of Cellular Stress Biology, School of Pharmaceutical Sciences, Fujian Provincial Key Laboratory of Innovative Drug Target Research, Xiamen University, Xiamen 361102, China
| | - Ziheng Wei
- State Key Laboratory of Cellular Stress Biology, School of Pharmaceutical Sciences, Fujian Provincial Key Laboratory of Innovative Drug Target Research, Xiamen University, Xiamen 361102, China
| | - Yueting Gu
- State Key Laboratory of Cellular Stress Biology, School of Pharmaceutical Sciences, Fujian Provincial Key Laboratory of Innovative Drug Target Research, Xiamen University, Xiamen 361102, China
| | - Yandan Ren
- State Key Laboratory of Cellular Stress Biology, School of Pharmaceutical Sciences, Fujian Provincial Key Laboratory of Innovative Drug Target Research, Xiamen University, Xiamen 361102, China
| | - Wenyi Hua
- State Key Laboratory of Cellular Stress Biology, School of Pharmaceutical Sciences, Fujian Provincial Key Laboratory of Innovative Drug Target Research, Xiamen University, Xiamen 361102, China
| | - Yongtao Zhang
- State Key Laboratory of Cellular Stress Biology, School of Pharmaceutical Sciences, Fujian Provincial Key Laboratory of Innovative Drug Target Research, Xiamen University, Xiamen 361102, China
| | - Xiaoxi Liu
- State Key Laboratory of Cellular Stress Biology, School of Pharmaceutical Sciences, Fujian Provincial Key Laboratory of Innovative Drug Target Research, Xiamen University, Xiamen 361102, China
| | - Cong Jiang
- State Key Laboratory of Cellular Stress Biology, School of Pharmaceutical Sciences, Fujian Provincial Key Laboratory of Innovative Drug Target Research, Xiamen University, Xiamen 361102, China
| | - Ruijuan Zhuang
- State Key Laboratory of Cellular Stress Biology, School of Pharmaceutical Sciences, Fujian Provincial Key Laboratory of Innovative Drug Target Research, Xiamen University, Xiamen 361102, China
| | - Wanjin Hong
- State Key Laboratory of Cellular Stress Biology, School of Pharmaceutical Sciences, Fujian Provincial Key Laboratory of Innovative Drug Target Research, Xiamen University, Xiamen 361102, China
- Institute of Molecular and Cell Biology, A*STAR (Agency of Science, Technology and Research), Singapore 138673, Singapore
| | - Tuanlao Wang
- State Key Laboratory of Cellular Stress Biology, School of Pharmaceutical Sciences, Fujian Provincial Key Laboratory of Innovative Drug Target Research, Xiamen University, Xiamen 361102, China
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4
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Chen L, Zhang J, Xu W, Chen J, Tang Y, Xiong S, Li Y, Zhang H, Li M, Liu Z. Cholesterol-rich lysosomes induced by respiratory syncytial virus promote viral replication by blocking autophagy flux. Nat Commun 2024; 15:6311. [PMID: 39060258 PMCID: PMC11282085 DOI: 10.1038/s41467-024-50711-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Accepted: 07/09/2024] [Indexed: 07/28/2024] Open
Abstract
Respiratory syncytial virus (RSV) hijacks cholesterol or autophagy pathways to facilitate optimal replication. However, our understanding of the associated molecular mechanisms remains limited. Here, we show that RSV infection blocks cholesterol transport from lysosomes to the endoplasmic reticulum by downregulating the activity of lysosomal acid lipase, activates the SREBP2-LDLR axis, and promotes uptake and accumulation of exogenous cholesterol in lysosomes. High cholesterol levels impair the VAP-A-binding activity of ORP1L and promote the recruitment of dynein-dynactin, PLEKHM1, or HOPS VPS39 to Rab7-RILP, thereby facilitating minus-end transport of autophagosomes and autolysosome formation. Acidification inhibition and dysfunction of cholesterol-rich lysosomes impair autophagy flux by inhibiting autolysosome degradation, which promotes the accumulation of RSV fusion protein. RSV-F storage is nearly abolished after cholesterol depletion or knockdown of LDLR. Most importantly, the knockout of LDLR effectively inhibits RSV infection in vivo. These findings elucidate the molecular mechanism of how RSV co-regulates lysosomal cholesterol reprogramming and autophagy and reveal LDLR as a novel target for anti-RSV drug development.
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Affiliation(s)
- Lifeng Chen
- State Key Laboratory of Bioactive Molecules and Druggability Assessment & College of Pharmacy, Jinan University, Guangzhou, China
- Department of Dermatology, The First Affiliated Hospital, Jinan University, Guangzhou, China
| | - Jingjing Zhang
- State Key Laboratory of Bioactive Molecules and Druggability Assessment & College of Pharmacy, Jinan University, Guangzhou, China
| | - Weibin Xu
- State Key Laboratory of Bioactive Molecules and Druggability Assessment & College of Pharmacy, Jinan University, Guangzhou, China
| | - Jiayi Chen
- State Key Laboratory of Bioactive Molecules and Druggability Assessment & College of Pharmacy, Jinan University, Guangzhou, China
| | - Yujun Tang
- State Key Laboratory of Bioactive Molecules and Druggability Assessment & College of Pharmacy, Jinan University, Guangzhou, China
| | - Si Xiong
- State Key Laboratory of Bioactive Molecules and Druggability Assessment & College of Pharmacy, Jinan University, Guangzhou, China
| | - Yaolan Li
- State Key Laboratory of Bioactive Molecules and Druggability Assessment & College of Pharmacy, Jinan University, Guangzhou, China
| | - Hong Zhang
- Department of Dermatology, The First Affiliated Hospital, Jinan University, Guangzhou, China.
| | - Manmei Li
- State Key Laboratory of Bioactive Molecules and Druggability Assessment & College of Pharmacy, Jinan University, Guangzhou, China.
| | - Zhong Liu
- State Key Laboratory of Bioactive Molecules and Druggability Assessment & College of Pharmacy, Jinan University, Guangzhou, China.
- Guangdong Provincial Key Laboratory of Bioengineering Medicine & College of Life Science and Technology, Jinan University, Guangzhou, China.
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5
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Bandyopadhyay S, Adebayo D, Obaseki E, Hariri H. Lysosomal membrane contact sites: Integrative hubs for cellular communication and homeostasis. CURRENT TOPICS IN MEMBRANES 2024; 93:85-116. [PMID: 39181579 DOI: 10.1016/bs.ctm.2024.07.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/27/2024]
Abstract
Lysosomes are more than just cellular recycling bins; they play a crucial role in regulating key cellular functions. Proper lysosomal function is essential for growth pathway regulation, cell proliferation, and metabolic homeostasis. Impaired lysosomal function is associated with lipid storage disorders and neurodegenerative diseases. Lysosomes form extensive and dynamic close contacts with the membranes of other organelles, including the endoplasmic reticulum, mitochondria, peroxisomes, and lipid droplets. These membrane contacts sites (MCSs) are vital for many lysosomal functions. In this chapter, we will explore lysosomal MCSs focusing on the machinery that mediates these contacts, how they are regulated, and their functional implications on physiology and pathology.
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Affiliation(s)
- Sumit Bandyopadhyay
- Department of Biological Sciences, Wayne State University, Detroit, MI, United States
| | - Daniel Adebayo
- Department of Biological Sciences, Wayne State University, Detroit, MI, United States
| | - Eseiwi Obaseki
- Department of Biological Sciences, Wayne State University, Detroit, MI, United States
| | - Hanaa Hariri
- Department of Biological Sciences, Wayne State University, Detroit, MI, United States.
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6
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Ke PY. Molecular Mechanism of Autophagosome-Lysosome Fusion in Mammalian Cells. Cells 2024; 13:500. [PMID: 38534345 DOI: 10.3390/cells13060500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2024] [Revised: 03/11/2024] [Accepted: 03/12/2024] [Indexed: 03/28/2024] Open
Abstract
In eukaryotes, targeting intracellular components for lysosomal degradation by autophagy represents a catabolic process that evolutionarily regulates cellular homeostasis. The successful completion of autophagy initiates the engulfment of cytoplasmic materials within double-membrane autophagosomes and subsequent delivery to autolysosomes for degradation by acidic proteases. The formation of autolysosomes relies on the precise fusion of autophagosomes with lysosomes. In recent decades, numerous studies have provided insights into the molecular regulation of autophagosome-lysosome fusion. In this review, an overview of the molecules that function in the fusion of autophagosomes with lysosomes is provided. Moreover, the molecular mechanism underlying how these functional molecules regulate autophagosome-lysosome fusion is summarized.
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Affiliation(s)
- Po-Yuan Ke
- Department of Biochemistry & Molecular Biology, Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan
- Liver Research Center, Chang Gung Memorial Hospital, Taoyuan 33305, Taiwan
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7
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Jiang M, Wu W, Xiong Z, Yu X, Ye Z, Wu Z. Targeting autophagy drug discovery: Targets, indications and development trends. Eur J Med Chem 2024; 267:116117. [PMID: 38295689 DOI: 10.1016/j.ejmech.2023.116117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Revised: 12/30/2023] [Accepted: 12/31/2023] [Indexed: 02/25/2024]
Abstract
Autophagy plays a vital role in sustaining cellular homeostasis and its alterations have been implicated in the etiology of many diseases. Drugs development targeting autophagy began decades ago and hundreds of agents were developed, some of which are licensed for the clinical usage. However, no existing intervention specifically aimed at modulating autophagy is available. The obstacles that prevent drug developments come from the complexity of the actual impact of autophagy regulators in disease scenarios. With the development and application of new technologies, several promising categories of compounds for autophagy-based therapy have emerged in recent years. In this paper, the autophagy-targeted drugs based on their targets at various hierarchical sites of the autophagic signaling network, e.g., the upstream and downstream of the autophagosome and the autophagic components with enzyme activities are reviewed and analyzed respectively, with special attention paid to those at preclinical or clinical trials. The drugs tailored to specific autophagy alone and combination with drugs/adjuvant therapies widely used in clinical for various diseases treatments are also emphasized. The emerging drug design and development targeting selective autophagy receptors (SARs) and their related proteins, which would be expected to arrest or reverse the progression of disease in various cancers, inflammation, neurodegeneration, and metabolic disorders, are critically reviewed. And the challenges and perspective in clinically developing autophagy-targeted drugs and possible combinations with other medicine are considered in the review.
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Affiliation(s)
- Mengjia Jiang
- Department of Pharmacology and Pharmacy, China Jiliang University, China
| | - Wayne Wu
- College of Osteopathic Medicine, New York Institute of Technology, USA
| | - Zijie Xiong
- Department of Pharmacology and Pharmacy, China Jiliang University, China
| | - Xiaoping Yu
- Department of Biology, China Jiliang University, China
| | - Zihong Ye
- Department of Biology, China Jiliang University, China
| | - Zhiping Wu
- Department of Pharmacology and Pharmacy, China Jiliang University, China.
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8
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Chadwick SR, Barreda D, Wu JZ, Ye G, Yusuf B, Ren D, Freeman SA. Two-pore channels regulate endomembrane tension to enable remodeling and resolution of phagolysosomes. Proc Natl Acad Sci U S A 2024; 121:e2309465121. [PMID: 38354262 PMCID: PMC10895354 DOI: 10.1073/pnas.2309465121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Accepted: 12/21/2023] [Indexed: 02/16/2024] Open
Abstract
Phagocytes promptly resolve ingested targets to replenish lysosomes and maintain their responsiveness. The resolution process requires that degradative hydrolases, solute transporters, and proteins involved in lipid traffic are delivered and made active in phagolysosomes. It also involves extensive membrane remodeling. We report that cation channels that localize to phagolysosomes were essential for resolution. Specifically, the conductance of Na+ by two-pore channels (TPCs) and the presence of a Na+ gradient between the phagolysosome lumen and the cytosol were critical for the controlled release of membrane tension that permits deformation of the limiting phagolysosome membrane. In turn, membrane deformation was a necessary step to efficiently transport the cholesterol extracted from cellular targets, permeabilizing them to hydrolases. These results place TPCs as regulators of endomembrane remodeling events that precede target degradation in cases when the target is bound by a cholesterol-containing membrane. The findings may help to explain lipid metabolism dysfunction and autophagic flux impairment reported in TPC KO mice and establish stepwise regulation to the resolution process that begins with lysis of the target.
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Affiliation(s)
- Sarah R. Chadwick
- Program in Cell Biology, Hospital for Sick Children, Toronto, ONM5G 0A4, Canada
| | - Dante Barreda
- Program in Cell Biology, Hospital for Sick Children, Toronto, ONM5G 0A4, Canada
| | - Jing Ze Wu
- Program in Cell Biology, Hospital for Sick Children, Toronto, ONM5G 0A4, Canada
- Department of Biochemistry, University of Toronto, Toronto, ONM5S 1A8, Canada
| | - Gang Ye
- Program in Cell Biology, Hospital for Sick Children, Toronto, ONM5G 0A4, Canada
| | - Bushra Yusuf
- Program in Cell Biology, Hospital for Sick Children, Toronto, ONM5G 0A4, Canada
- Institute of Medical Science, University of Toronto, Toronto, ONM5S 1A8, Canada
| | - Dejian Ren
- Department of Biology, University of Pennsylvania, Philadelphia, PA19104
| | - Spencer A. Freeman
- Program in Cell Biology, Hospital for Sick Children, Toronto, ONM5G 0A4, Canada
- Department of Biochemistry, University of Toronto, Toronto, ONM5S 1A8, Canada
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9
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Ma L, Han T, Zhan YA. Mechanism and role of mitophagy in the development of severe infection. Cell Death Discov 2024; 10:88. [PMID: 38374038 PMCID: PMC10876966 DOI: 10.1038/s41420-024-01844-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 01/31/2024] [Accepted: 02/01/2024] [Indexed: 02/21/2024] Open
Abstract
Mitochondria produce adenosine triphosphate and potentially contribute to proinflammatory responses and cell death. Mitophagy, as a conservative phenomenon, scavenges waste mitochondria and their components in the cell. Recent studies suggest that severe infections develop alongside mitochondrial dysfunction and mitophagy abnormalities. Restoring mitophagy protects against excessive inflammation and multiple organ failure in sepsis. Here, we review the normal mitophagy process, its interaction with invading microorganisms and the immune system, and summarize the mechanism of mitophagy dysfunction during severe infection. We highlight critical role of normal mitophagy in preventing severe infection.
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Affiliation(s)
- Lixiu Ma
- Department of Respiratory and Critical Care Medicine, the 1st Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, 330006, Jiangxi, China
| | - Tianyu Han
- Jiangxi Institute of Respiratory Disease, the 1st Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, 330006, Jiangxi, China
| | - Yi-An Zhan
- Department of Respiratory and Critical Care Medicine, the 1st Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, 330006, Jiangxi, China.
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10
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Kundu S, Sarkar S, Acharya Chowdhury A. Anti-Leukemic Attributes of Natural Compounds Targeting Autophagy: A Closer Look into the Molecular Mechanisms. Nutr Cancer 2024; 76:236-251. [PMID: 38263604 DOI: 10.1080/01635581.2024.2306682] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Accepted: 01/10/2024] [Indexed: 01/25/2024]
Abstract
Leukemia is a heterogeneous clonal cancer that affects millions of individuals around the world. Despite substantial breakthroughs in cancer treatment, traditional chemotherapy and radiotherapy remain ineffective, and therapeutic resistance still stands as a big obstacle. As a result, there is an increasing attention being paid currently toward the potency of natural compounds as a complementary or alternative therapy for leukemia. Autophagy, a conserved cellular process where damaged or defective cytosolic components and macromolecules are destroyed and recycled, plays a dual role in promoting or suppressing the continuance of cancer at different junctures of its development. Current studies have reported that autophagy has a cardinal function in the genesis and progression of leukemia, making it a promising target for novel treatments. In this review, we have explored the effectiveness of certain natural compounds, such as curcumin, resveratrol, tanshinone IIA, quercetin, tetrandrine, parthenolide, berberine, pristimerin, and alantolactone, that modulate autophagy and regulate its associated signaling cascades at a molecular level in different types of leukemia. They have been shown to have synergistic effects with conventional chemotherapy, emphasizing their potential as supplementary medicines. However, additional research is required to fully comprehend their mechanisms of action and to maximize their role in clinical perspectives.
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Affiliation(s)
- Sweta Kundu
- Department of Biosciences, JIS University, Kolkata, India
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11
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Nambiar A, Manjithaya R. Driving autophagy - the role of molecular motors. J Cell Sci 2024; 137:jcs260481. [PMID: 38329417 DOI: 10.1242/jcs.260481] [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] [Indexed: 02/09/2024] Open
Abstract
Most of the vesicular transport pathways inside the cell are facilitated by molecular motors that move along cytoskeletal networks. Autophagy is a well-explored catabolic pathway that is initiated by the formation of an isolation membrane known as the phagophore, which expands to form a double-membraned structure that captures its cargo and eventually moves towards the lysosomes for fusion. Molecular motors and cytoskeletal elements have been suggested to participate at different stages of the process as the autophagic vesicles move along cytoskeletal tracks. Dynein and kinesins govern autophagosome trafficking on microtubules through the sequential recruitment of their effector proteins, post-translational modifications and interactions with LC3-interacting regions (LIRs). In contrast, myosins are actin-based motors that participate in various stages of the autophagic flux, as well as in selective autophagy pathways. However, several outstanding questions remain with regard to how the dominance of a particular motor protein over another is controlled, and to the molecular mechanisms that underlie specific disease variants in motor proteins. In this Review, we aim to provide an overview of the role of molecular motors in autophagic flux, as well as highlight their dysregulation in diseases, such as neurodegenerative disorders and pathogenic infections, and ageing.
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Affiliation(s)
- Akshaya Nambiar
- Autophagy Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064, India
| | - Ravi Manjithaya
- Autophagy Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064, India
- Neuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064, India
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12
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Arya SB, Collie SP, Parent CA. The ins-and-outs of exosome biogenesis, secretion, and internalization. Trends Cell Biol 2024; 34:90-108. [PMID: 37507251 PMCID: PMC10811273 DOI: 10.1016/j.tcb.2023.06.006] [Citation(s) in RCA: 32] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Revised: 06/20/2023] [Accepted: 06/22/2023] [Indexed: 07/30/2023]
Abstract
Exosomes are specialized cargo delivery vesicles secreted from cells by fusion of multivesicular bodies (MVBs) with the plasma membrane (PM). While the function of exosomes during physiological and pathological events has been extensively reported, there remains a lack of understanding of the mechanisms that regulate exosome biogenesis, secretion, and internalization. Recent technological and methodological advances now provide details about MVB/exosome structure as well as the pathways of exosome biogenesis, secretion, and uptake. In this review, we outline our current understanding of these processes and highlight outstanding questions following on recent discoveries in the field.
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Affiliation(s)
- Subhash B Arya
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
| | - Samuel P Collie
- Cellular and Molecular Biology Graduate Program, University of Michigan, Ann Arbor, MI, USA
| | - Carole A Parent
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA; Cellular and Molecular Biology Graduate Program, University of Michigan, Ann Arbor, MI, USA; Department of Pharmacology, University of Michigan, Ann Arbor, MI, USA; Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI, USA; Rogel Cancer Center, University of Michigan, Ann Arbor, MI, USA.
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13
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Skeyni A, Pradignac A, Matz RL, Terrand J, Boucher P. Cholesterol trafficking, lysosomal function, and atherosclerosis. Am J Physiol Cell Physiol 2024; 326:C473-C486. [PMID: 38145298 DOI: 10.1152/ajpcell.00415.2023] [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: 09/05/2023] [Revised: 12/17/2023] [Accepted: 12/18/2023] [Indexed: 12/26/2023]
Abstract
Despite years of study and major research advances over the past 50 years, atherosclerotic diseases continue to rank as the leading global cause of death. Accumulation of cholesterol within the vascular wall remains the main problem and represents one of the early steps in the development of atherosclerotic lesions. There is a complex relationship between vesicular cholesterol transport and atherosclerosis, and abnormalities in cholesterol trafficking can contribute to the development and progression of the lesions. The dysregulation of vesicular cholesterol transport and lysosomal function fosters the buildup of cholesterol within various intracytoplasmic compartments, including lysosomes and lipid droplets. This, in turn, promotes the hallmark formation of foam cells, a defining feature of early atherosclerosis. Multiple cellular processes, encompassing endocytosis, exocytosis, intracellular trafficking, and autophagy, play crucial roles in influencing foam cell formation and atherosclerotic plaque stability. In this review, we highlight recent advances in the understanding of the intricate mechanisms of vesicular cholesterol transport and its relationship with atherosclerosis and discuss the importance of understanding these mechanisms in developing strategies to prevent or treat this prevalent cardiovascular disease.
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Affiliation(s)
- Alaa Skeyni
- UMR-S INSERM 1109, University of Strasbourg, Strasbourg, France
| | - Alain Pradignac
- UMR-S INSERM 1109, University of Strasbourg, Strasbourg, France
| | - Rachel L Matz
- UMR-S INSERM 1109, University of Strasbourg, Strasbourg, France
| | - Jérôme Terrand
- UMR-S INSERM 1109, University of Strasbourg, Strasbourg, France
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14
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Liénard C, Pintart A, Bomont P. Neuronal Autophagy: Regulations and Implications in Health and Disease. Cells 2024; 13:103. [PMID: 38201307 PMCID: PMC10778363 DOI: 10.3390/cells13010103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Revised: 12/02/2023] [Accepted: 12/27/2023] [Indexed: 01/12/2024] Open
Abstract
Autophagy is a major degradative pathway that plays a key role in sustaining cell homeostasis, integrity, and physiological functions. Macroautophagy, which ensures the clearance of cytoplasmic components engulfed in a double-membrane autophagosome that fuses with lysosomes, is orchestrated by a complex cascade of events. Autophagy has a particularly strong impact on the nervous system, and mutations in core components cause numerous neurological diseases. We first review the regulation of autophagy, from autophagosome biogenesis to lysosomal degradation and associated neurodevelopmental/neurodegenerative disorders. We then describe how this process is specifically regulated in the axon and in the somatodendritic compartment and how it is altered in diseases. In particular, we present the neuronal specificities of autophagy, with the spatial control of autophagosome biogenesis, the close relationship of maturation with axonal transport, and the regulation by synaptic activity. Finally, we discuss the physiological functions of autophagy in the nervous system, during development and in adulthood.
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Affiliation(s)
- Caroline Liénard
- NeuroMyoGene Institute—PGNM, CNRS UMR 5261—INSERM U1315, University of Claude Bernard Lyon 1, 69008 Lyon, France; (C.L.); (A.P.)
- CHU Montpellier, University of Montpellier, 34295 Montpellier, France
| | - Alexandre Pintart
- NeuroMyoGene Institute—PGNM, CNRS UMR 5261—INSERM U1315, University of Claude Bernard Lyon 1, 69008 Lyon, France; (C.L.); (A.P.)
| | - Pascale Bomont
- NeuroMyoGene Institute—PGNM, CNRS UMR 5261—INSERM U1315, University of Claude Bernard Lyon 1, 69008 Lyon, France; (C.L.); (A.P.)
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15
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Kamath AJ, Chandy AS, Joseph AA, Gorantla JN, Donadkar AD, Nath LR, Sharifi-Rad J, Calina D. Embelin: A multifaceted anticancer agent with translational potential in targeting tumor progression and metastasis. EXCLI JOURNAL 2023; 22:1311-1329. [PMID: 38234968 PMCID: PMC10792175 DOI: 10.17179/excli2023-6590] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Accepted: 11/23/2023] [Indexed: 01/19/2024]
Abstract
Embelin, a natural para-benzoquinone product, is derived from plants of the Embelia genus, particularly Embelia ribes Burm.f. A staple in traditional medicinal formulations for centuries, Embelin's pharmacological actions are attributed to the hydroxyl benzoquinone present in its structure. Its therapeutic potential is bolstered by unique physical and chemical properties. Recently, Embelin, recognized as a non-peptidic, cell-permeable small inhibitor of the X-linked inhibitor of apoptosis protein (XIAP), has garnered significant attention for its anticancer activity. It demonstrates various anticancer mechanisms, such as apoptosis induction, cell cycle arrest, and autophagy, in different cancer types. Additionally, Embelin modulates several signal transduction pathways, including NF-κB, PI3Kinase/AKT, and STAT3, effectively inhibiting the proliferation of diverse cancer cell lines. This literature review illuminates the anticancer potential of Embelin, detailing its mechanisms of action and prospective clinical applications, based on relevant scientific literature from the past decade sourced from various electronic databases. See also the Graphical abstract(Fig. 1).
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Affiliation(s)
- Adithya Jayaprakash Kamath
- Department of Pharmacognosy, Amrita School of Pharmacy, Amrita Vishwa Vidyapeetham, AIMS Health Sciences Campus, Kochi-682 041, India
- Department of Pharmaceutics, Amrita School of Pharmacy, Amrita Vishwa Vidyapeetham, AIMS Health Sciences Campus, Kochi-682 041, India
| | - Alda Sara Chandy
- Department of Pharmacognosy, Amrita School of Pharmacy, Amrita Vishwa Vidyapeetham, AIMS Health Sciences Campus, Kochi-682 041, India
| | - Aina Ann Joseph
- Department of Pharmacognosy, Amrita School of Pharmacy, Amrita Vishwa Vidyapeetham, AIMS Health Sciences Campus, Kochi-682 041, India
| | - Jaggiah N. Gorantla
- Department of Chemistry, Wayne State University, Detroit-48202, Michigan, USA
| | - Asawari Dilip Donadkar
- Department of Pharmacognosy, Amrita School of Pharmacy, Amrita Vishwa Vidyapeetham, AIMS Health Sciences Campus, Kochi-682 041, India
- Department of Pharmaceutics, Amrita School of Pharmacy, Amrita Vishwa Vidyapeetham, AIMS Health Sciences Campus, Kochi-682 041, India
| | - Lekshmi R. Nath
- Department of Pharmacognosy, Amrita School of Pharmacy, Amrita Vishwa Vidyapeetham, AIMS Health Sciences Campus, Kochi-682 041, India
| | | | - Daniela Calina
- Department of Clinical Pharmacy, University of Medicine and Pharmacy of Craiova, 200349 Craiova, Romania
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16
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Mulligan RJ, Winckler B. Regulation of Endosomal Trafficking by Rab7 and Its Effectors in Neurons: Clues from Charcot-Marie-Tooth 2B Disease. Biomolecules 2023; 13:1399. [PMID: 37759799 PMCID: PMC10527268 DOI: 10.3390/biom13091399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2023] [Revised: 09/09/2023] [Accepted: 09/14/2023] [Indexed: 09/29/2023] Open
Abstract
Intracellular endosomal trafficking controls the balance between protein degradation and synthesis, i.e., proteostasis, but also many of the cellular signaling pathways that emanate from activated growth factor receptors after endocytosis. Endosomal trafficking, sorting, and motility are coordinated by the activity of small GTPases, including Rab proteins, whose function as molecular switches direct activity at endosomal membranes through effector proteins. Rab7 is particularly important in the coordination of the degradative functions of the pathway. Rab7 effectors control endosomal maturation and the properties of late endosomal and lysosomal compartments, such as coordination of recycling, motility, and fusion with downstream compartments. The spatiotemporal regulation of endosomal receptor trafficking is particularly challenging in neurons because of their enormous size, their distinct intracellular domains with unique requirements (dendrites vs. axons), and their long lifespans as postmitotic, differentiated cells. In Charcot-Marie-Tooth 2B disease (CMT2B), familial missense mutations in Rab7 cause alterations in GTPase cycling and trafficking, leading to an ulcero-mutilating peripheral neuropathy. The prevailing hypothesis to account for CMT2B pathologies is that CMT2B-associated Rab7 alleles alter endocytic trafficking of the neurotrophin NGF and its receptor TrkA and, thereby, disrupt normal trophic signaling in the peripheral nervous system, but other Rab7-dependent pathways are also impacted. Here, using TrkA as a prototypical endocytic cargo, we review physiologic Rab7 effector interactions and control in neurons. Since neurons are among the largest cells in the body, we place particular emphasis on the temporal and spatial regulation of endosomal sorting and trafficking in neuronal processes. We further discuss the current findings in CMT2B mutant Rab7 models, the impact of mutations on effector interactions or balance, and how this dysregulation may confer disease.
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Affiliation(s)
- Ryan J. Mulligan
- Department of Cell Biology, University of Virginia, Charlottesville, VA 22903, USA
- Medical Scientist Training Program, University of Virginia, Charlottesville, VA 22903, USA
| | - Bettina Winckler
- Department of Cell Biology, University of Virginia, Charlottesville, VA 22903, USA
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17
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Xie Y, Zhou Y, Wang J, Du L, Ren Y, Liu F. Ferroptosis, autophagy, tumor and immunity. Heliyon 2023; 9:e19799. [PMID: 37810047 PMCID: PMC10559173 DOI: 10.1016/j.heliyon.2023.e19799] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Revised: 08/20/2023] [Accepted: 09/01/2023] [Indexed: 10/10/2023] Open
Abstract
Ferroptosis was first proposed in 2012, a new form of cell death. Autophagy plays a crucial role in cell clearance and maintaining homeostasis. Autophagy is involved in the initial step of ferroptosis under the action of histone elements such as NCOA4, RAB7A, and BECN1. Ferroptosis and autophagy are involved in tumor progression, treatment, and drug resistance in the tumor microenvironment. In this review, we described the mechanisms of ferroptosis, autophagy, and tumor and immunotherapy, respectively, and emphasized the relationship between autophagy-related ferroptosis and tumor.
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Affiliation(s)
| | | | - Jiale Wang
- Department of Medical Oncology, Harbin Medical University Cancer Hospital, Harbin, 150081, China
| | - Lijuan Du
- Department of Medical Oncology, Harbin Medical University Cancer Hospital, Harbin, 150081, China
| | - Yuanyuan Ren
- Department of Medical Oncology, Harbin Medical University Cancer Hospital, Harbin, 150081, China
| | - Fang Liu
- Department of Medical Oncology, Harbin Medical University Cancer Hospital, Harbin, 150081, China
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18
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Li W, Pang Y, Jin K, Wang Y, Wu Y, Luo J, Xu W, Zhang X, Xu R, Wang T, Jiao L. Membrane contact sites orchestrate cholesterol homeostasis that is central to vascular aging. WIREs Mech Dis 2023; 15:e1612. [PMID: 37156598 DOI: 10.1002/wsbm.1612] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2022] [Revised: 02/12/2023] [Accepted: 04/19/2023] [Indexed: 05/10/2023]
Abstract
Chronological age causes structural and functional vascular deterioration and is a well-established risk factor for the development of cardiovascular diseases, leading to more than 40% of all deaths in the elderly. The etiology of vascular aging is complex; a significant impact arises from impaired cholesterol homeostasis. Cholesterol level is balanced through synthesis, uptake, transport, and esterification, the processes executed by multiple organelles. Moreover, organelles responsible for cholesterol homeostasis are spatially and functionally coordinated instead of isolated by forming the membrane contact sites. Membrane contact, mediated by specific protein-protein interaction, pulls opposing organelles together and creates the hybrid place for cholesterol transfer and further signaling. The membrane contact-dependent cholesterol transfer, together with the vesicular transport, maintains cholesterol homeostasis and has intimate implications in a growing list of diseases, including vascular aging-related diseases. Here, we summarized the latest advances regarding cholesterol homeostasis by highlighting the membrane contact-based regulatory mechanism. We also describe the downstream signaling under cholesterol homeostasis perturbations, prominently in cholesterol-rich conditions, stimulating age-dependent organelle dysfunction and vascular aging. Finally, we discuss potential cholesterol-targeting strategies for therapists regarding vascular aging-related diseases. This article is categorized under: Cardiovascular Diseases > Molecular and Cellular Physiology.
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Affiliation(s)
- Wenjing Li
- Laboratory of Computational Biology and Machine Intelligence, National Laboratory of Pattern Recognition, Institute of Automation, Chinese Academy of Sciences, Beijing, China
- School of Artificial Intelligence, University of Chinese Academy of Sciences, Beijing, China
| | - Yiyun Pang
- Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
| | - Kehan Jin
- Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
| | - Yuru Wang
- Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
| | - Yujie Wu
- Laboratory of Computational Biology and Machine Intelligence, National Laboratory of Pattern Recognition, Institute of Automation, Chinese Academy of Sciences, Beijing, China
| | - Jichang Luo
- Department of Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China
- China International Neuroscience Institute (China-INI), Beijing, China
| | - Wenlong Xu
- Department of Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China
- China International Neuroscience Institute (China-INI), Beijing, China
| | - Xiao Zhang
- Department of Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China
- China International Neuroscience Institute (China-INI), Beijing, China
| | - Ran Xu
- Department of Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China
- China International Neuroscience Institute (China-INI), Beijing, China
| | - Tao Wang
- Department of Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China
- China International Neuroscience Institute (China-INI), Beijing, China
| | - Liqun Jiao
- Department of Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China
- China International Neuroscience Institute (China-INI), Beijing, China
- Department of Interventional Radiology, Xuanwu Hospital, Capital Medical University, Beijing, China
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19
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Benitez-Fuente F, Botella MA. Biological roles of plant synaptotagmins. Eur J Cell Biol 2023; 102:151335. [PMID: 37390668 DOI: 10.1016/j.ejcb.2023.151335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 06/19/2023] [Accepted: 06/19/2023] [Indexed: 07/02/2023] Open
Abstract
Plant synaptotagmins (SYTs) are resident proteins of the endoplasmic reticulum (ER). They are characterized by an N-terminal transmembrane region and C2 domains at the C-terminus, which tether the ER to the plasma membrane (PM). In addition to their tethering role, SYTs contain a lipid-harboring SMP domain, essential for shuttling lipids between the ER and the PM. There is now abundant literature on Arabidopsis SYT1, the best-characterized family member, which link it to biotic and abiotic responses as well as to ER morphology. Here, we review the current knowledge of SYT members, focusing on their role in stress, and discuss how these roles can be related to their tethering and lipid transport functions. Finally, we contextualize this information about SYTs with their homologs, the yeast tricalbins and the mammalian extended synaptotagmins.
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Affiliation(s)
- Francisco Benitez-Fuente
- Departamento de Biología Molecular y Bioquímica, Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora", Universidad de Málaga, Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Universidad de Málaga, Málaga 12907, Spain
| | - Miguel A Botella
- Departamento de Biología Molecular y Bioquímica, Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora", Universidad de Málaga, Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Universidad de Málaga, Málaga 12907, Spain.
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20
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Zhang T, Li Y, Li C, Zang J, Gao E, Kroon JT, Qu X, Hussey PJ, Wang P. Exo84c interacts with VAP27 to regulate exocytotic compartment degradation and stigma senescence. Nat Commun 2023; 14:4888. [PMID: 37580356 PMCID: PMC10425460 DOI: 10.1038/s41467-023-40729-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Accepted: 08/08/2023] [Indexed: 08/16/2023] Open
Abstract
In plants, exocyst subunit isoforms exhibit significant functional diversity in that they are involved in either protein secretion or autophagy, both of which are essential for plant development and survival. Although the molecular basis of autophagy is widely reported, its contribution to plant reproduction is not very clear. Here, we have identified Exo84c, a higher plant-specific Exo84 isoform, as having a unique function in modulating exocytotic compartment degradation during stigmatic tissue senescence. This process is achieved through its interaction with the ER localised VAP27 proteins, which regulate the turnover of Exo84c through the autophagy pathway. VAP27 recruits Exo84c onto the ER membrane as well as numerous ER-derived autophagosomes that are labelled with ATG8. These Exo84c/exocyst and VAP27 positive structures are accumulated in the vacuole for degradation, and this process is partially perturbed in the exo84c knock-out mutants. Interestingly, the exo84c mutant showed a prolonged effective pollination period with higher seed sets, possibly because of the delayed stigmatic senescence when Exo84c regulated autophagy is blocked. In conclusion, our studies reveal a link between the exocyst complex and the ER network in regulating the degradation of exocytosis vesicles, a process that is essential for normal papilla cell senescence and flower receptivity.
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Affiliation(s)
- Tong Zhang
- National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, 430070, Hubei Province, China
- Hubei Hongshan Laboratory, Wuhan, 430070, China
| | - Yifan Li
- National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, 430070, Hubei Province, China
- Hubei Hongshan Laboratory, Wuhan, 430070, China
| | - Chengyang Li
- National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, 430070, Hubei Province, China
- Hubei Hongshan Laboratory, Wuhan, 430070, China
| | - Jingze Zang
- National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, 430070, Hubei Province, China
- Hubei Hongshan Laboratory, Wuhan, 430070, China
- Department of Biosciences, Durham University, South Road, Durham, DH1 3LE, UK
| | - Erlin Gao
- National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, 430070, Hubei Province, China
- Hubei Hongshan Laboratory, Wuhan, 430070, China
| | - Johan T Kroon
- Department of Biosciences, Durham University, South Road, Durham, DH1 3LE, UK
| | - Xiaolu Qu
- National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, 430070, Hubei Province, China
| | - Patrick J Hussey
- Department of Biosciences, Durham University, South Road, Durham, DH1 3LE, UK
| | - Pengwei Wang
- National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, 430070, Hubei Province, China.
- Hubei Hongshan Laboratory, Wuhan, 430070, China.
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21
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Yan C, Zheng L, Jiang S, Yang H, Guo J, Jiang LY, Li T, Zhang H, Bai Y, Lou Y, Zhang Q, Liang T, Schamel W, Wang H, Yang W, Wang G, Zhu ZJ, Song BL, Xu C. Exhaustion-associated cholesterol deficiency dampens the cytotoxic arm of antitumor immunity. Cancer Cell 2023:S1535-6108(23)00142-3. [PMID: 37244259 DOI: 10.1016/j.ccell.2023.04.016] [Citation(s) in RCA: 23] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2022] [Revised: 02/17/2023] [Accepted: 04/25/2023] [Indexed: 05/29/2023]
Abstract
The concept of targeting cholesterol metabolism to treat cancer has been widely tested in clinics, but the benefits are modest, calling for a complete understanding of cholesterol metabolism in intratumoral cells. We analyze the cholesterol atlas in the tumor microenvironment and find that intratumoral T cells have cholesterol deficiency, while immunosuppressive myeloid cells and tumor cells display cholesterol abundance. Low cholesterol levels inhibit T cell proliferation and cause autophagy-mediated apoptosis, particularly for cytotoxic T cells. In the tumor microenvironment, oxysterols mediate reciprocal alterations in the LXR and SREBP2 pathways to cause cholesterol deficiency of T cells, subsequently leading to aberrant metabolic and signaling pathways that drive T cell exhaustion/dysfunction. LXRβ depletion in chimeric antigen receptor T (CAR-T) cells leads to improved antitumor function against solid tumors. Since T cell cholesterol metabolism and oxysterols are generally linked to other diseases, the new mechanism and cholesterol-normalization strategy might have potential applications elsewhere.
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Affiliation(s)
- Chengsong Yan
- Key Laboratory of Systems Health Science of Zhejiang Province, School of Life Science, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou, 310024, China; State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology; University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Lin Zheng
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology; University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Shutan Jiang
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology; University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Haochen Yang
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology; University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Jun Guo
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology; University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Lu-Yi Jiang
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, China
| | - Tongzhou Li
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China
| | - Haosong Zhang
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China
| | - Yibing Bai
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology; University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Yu Lou
- Department of Hepatobiliary and Pancreatic Surgery, First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Qi Zhang
- Department of Hepatobiliary and Pancreatic Surgery, First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Tingbo Liang
- Department of Hepatobiliary and Pancreatic Surgery, First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Wolfgang Schamel
- Faculty of Biology, Albert-Ludwigs-University of Freiburg, Freiburg, Germany
| | - Haopeng Wang
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Weiwei Yang
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology; University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Guangchuan Wang
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology; University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Zheng-Jiang Zhu
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China
| | - Bao-Liang Song
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, China.
| | - Chenqi Xu
- Key Laboratory of Systems Health Science of Zhejiang Province, School of Life Science, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou, 310024, China; State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology; University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China.
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22
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Berlin I, Sapmaz A, Stévenin V, Neefjes J. Ubiquitin and its relatives as wizards of the endolysosomal system. J Cell Sci 2023; 136:288517. [PMID: 36825571 PMCID: PMC10022685 DOI: 10.1242/jcs.260101] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2023] Open
Abstract
The endolysosomal system comprises a dynamic constellation of vesicles working together to sense and interpret environmental cues and facilitate homeostasis. Integrating extracellular information with the internal affairs of the cell requires endosomes and lysosomes to be proficient in decision-making: fusion or fission; recycling or degradation; fast transport or contacts with other organelles. To effectively discriminate between these options, the endolysosomal system employs complex regulatory strategies that crucially rely on reversible post-translational modifications (PTMs) with ubiquitin (Ub) and ubiquitin-like (Ubl) proteins. The cycle of conjugation, recognition and removal of different Ub- and Ubl-modified states informs cellular protein stability and behavior at spatial and temporal resolution and is thus well suited to finetune macromolecular complex assembly and function on endolysosomal membranes. Here, we discuss how ubiquitylation (also known as ubiquitination) and its biochemical relatives orchestrate endocytic traffic and designate cargo fate, influence membrane identity transitions and support formation of membrane contact sites (MCSs). Finally, we explore the opportunistic hijacking of Ub and Ubl modification cascades by intracellular bacteria that remodel host trafficking pathways to invade and prosper inside cells.
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Affiliation(s)
- Ilana Berlin
- Oncode Institute, Department of Cell and Chemical Biology, Leiden University Medical Center LUMC, Einthovenweg 20, 2300RC Leiden, The Netherlands
| | - Aysegul Sapmaz
- Oncode Institute, Department of Cell and Chemical Biology, Leiden University Medical Center LUMC, Einthovenweg 20, 2300RC Leiden, The Netherlands
| | - Virginie Stévenin
- Oncode Institute, Department of Cell and Chemical Biology, Leiden University Medical Center LUMC, Einthovenweg 20, 2300RC Leiden, The Netherlands
| | - Jacques Neefjes
- Oncode Institute, Department of Cell and Chemical Biology, Leiden University Medical Center LUMC, Einthovenweg 20, 2300RC Leiden, The Netherlands
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23
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Vos M, Klein C, Hicks AA. Role of Ceramides and Sphingolipids in Parkinson's Disease. J Mol Biol 2023:168000. [PMID: 36764358 DOI: 10.1016/j.jmb.2023.168000] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 01/24/2023] [Accepted: 02/02/2023] [Indexed: 02/11/2023]
Abstract
Sphingolipids, including the basic ceramide, are a subset of bioactive lipids that consist of many different species. Sphingolipids are indispensable for proper neuronal function, and an increasing number of studies have emerged on the complexity and importance of these lipids in (almost) all biological processes. These include regulation of mitochondrial function, autophagy, and endosomal trafficking, which are affected in Parkinson's disease (PD). PD is the second most common neurodegenerative disorder and is characterized by the loss of dopaminergic neurons. Currently, PD cannot be cured due to the lack of knowledge of the exact pathogenesis. Nonetheless, important advances have identified molecular changes in mitochondrial function, autophagy, and endosomal function. Furthermore, recent studies have identified ceramide alterations in patients suffering from PD, and in PD models, suggesting a critical interaction between sphingolipids and related cellular processes in PD. For instance, autosomal recessive forms of PD cause mitochondrial dysfunction, including energy production or mitochondrial clearance, that is directly influenced by manipulating sphingolipids. Additionally, endo-lysosomal recycling is affected by genes that cause autosomal dominant forms of the disease, such as VPS35 and SNCA. Furthermore, endo-lysosomal recycling is crucial for transporting sphingolipids to different cellular compartments where they will execute their functions. This review will discuss mitochondrial dysfunction, defects in autophagy, and abnormal endosomal activity in PD and the role sphingolipids play in these vital molecular processes.
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Affiliation(s)
- Melissa Vos
- Institute of Neurogenetics, University of Luebeck, 23562 Luebeck, Germany.
| | - Christine Klein
- Institute of Neurogenetics, University of Luebeck, 23562 Luebeck, Germany
| | - Andrew A Hicks
- Institute for Biomedicine (affiliated to the University of Luebeck, Luebeck, Germany), Eurac Research, 39100 Bolzano, Italy. https://twitter.com/andrewhicks
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24
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Subra M, Dezi M, Bigay J, Lacas-Gervais S, Di Cicco A, Araújo ARD, Abélanet S, Fleuriot L, Debayle D, Gautier R, Patel A, Roussi F, Antonny B, Lévy D, Mesmin B. VAP-A intrinsically disordered regions enable versatile tethering at membrane contact sites. Dev Cell 2023; 58:121-138.e9. [PMID: 36693319 DOI: 10.1016/j.devcel.2022.12.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 10/21/2022] [Accepted: 12/20/2022] [Indexed: 01/24/2023]
Abstract
Membrane contact sites (MCSs) are heterogeneous in shape, composition, and dynamics. Despite this diversity, VAP proteins act as receptors for multiple FFAT motif-containing proteins and drive the formation of most MCSs that involve the endoplasmic reticulum (ER). Although the VAP-FFAT interaction is well characterized, no model explains how VAP adapts to its partners in various MCSs. We report that VAP-A localization to different MCSs depends on its intrinsically disordered regions (IDRs) in human cells. VAP-A interaction with PTPIP51 and VPS13A at ER-mitochondria MCS conditions mitochondria fusion by promoting lipid transfer and cardiolipin buildup. VAP-A also enables lipid exchange at ER-Golgi MCS by interacting with oxysterol-binding protein (OSBP) and CERT. However, removing IDRs from VAP-A restricts its distribution and function to ER-mitochondria MCS. Our data suggest that IDRs do not modulate VAP-A preference toward specific partners but do adjust their geometry to MCS organization and lifetime constraints. Thus, IDR-mediated VAP-A conformational flexibility ensures membrane tethering plasticity and efficiency.
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Affiliation(s)
- Mélody Subra
- Université Côte d'Azur, Inserm, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, 660 route des lucioles, 06560 Valbonne, France
| | - Manuela Dezi
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR168, Laboratoire Physico-Chimie Curie, 75005 Paris, France
| | - Joëlle Bigay
- Université Côte d'Azur, Inserm, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, 660 route des lucioles, 06560 Valbonne, France
| | - Sandra Lacas-Gervais
- Université Côte d'Azur, Centre Commun de Microscopie Appliquée, Parc Valrose, 06000 Nice, France
| | - Aurélie Di Cicco
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR168, Laboratoire Physico-Chimie Curie, 75005 Paris, France
| | - Ana Rita Dias Araújo
- Université Côte d'Azur, Inserm, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, 660 route des lucioles, 06560 Valbonne, France
| | - Sophie Abélanet
- Université Côte d'Azur, Inserm, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, 660 route des lucioles, 06560 Valbonne, France
| | - Lucile Fleuriot
- Université Côte d'Azur, Inserm, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, 660 route des lucioles, 06560 Valbonne, France
| | - Delphine Debayle
- Université Côte d'Azur, Inserm, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, 660 route des lucioles, 06560 Valbonne, France
| | - Romain Gautier
- Université Côte d'Azur, Inserm, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, 660 route des lucioles, 06560 Valbonne, France
| | - Amanda Patel
- Université Côte d'Azur, Inserm, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, 660 route des lucioles, 06560 Valbonne, France
| | - Fanny Roussi
- Institut de Chimie des Substances Naturelles, CNRS, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Bruno Antonny
- Université Côte d'Azur, Inserm, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, 660 route des lucioles, 06560 Valbonne, France
| | - Daniel Lévy
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR168, Laboratoire Physico-Chimie Curie, 75005 Paris, France
| | - Bruno Mesmin
- Université Côte d'Azur, Inserm, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, 660 route des lucioles, 06560 Valbonne, France.
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25
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Kurihara Y, Mitsunari K, Mukae N, Shoji H, Miyakawa T, Shirane M. PDZD8-deficient mice manifest behavioral abnormalities related to emotion, cognition, and adaptation due to dyslipidemia in the brain. Mol Brain 2023; 16:11. [PMID: 36658656 PMCID: PMC9854033 DOI: 10.1186/s13041-023-01002-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Accepted: 01/12/2023] [Indexed: 01/21/2023] Open
Abstract
Although dyslipidemia in the brain has been implicated in neurodegenerative disorders, the molecular mechanisms underlying its pathogenesis have been largely unclear. PDZD8 is a lipid transfer protein and mice deficient in PDZD8 (PDZD8-KO mice) manifest abnormal accumulation of cholesteryl esters (CEs) in the brain due to impaired lipophagy, the degradation system of lipid droplets. Here we show the detailed mechanism of PDZD8-dependent lipophagy. PDZD8 transports cholesterol to lipid droplets (LDs), and eventually promotes fusion of LDs and lysosomes. In addition, PDZD8-KO mice exhibit growth retardation, hyperactivity, reduced anxiety and fear, increased sensorimotor gating, and impaired cued fear conditioned memory and working memory. These results indicate that abnormal CE accumulation in the brain caused by PDZD8 deficiency affects emotion, cognition and adaptive behavior, and that PDZD8 plays an important role in the maintenance of brain function through lipid metabolism.
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Affiliation(s)
- Yuji Kurihara
- grid.260433.00000 0001 0728 1069Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, Aichi Japan
| | - Kotone Mitsunari
- grid.260433.00000 0001 0728 1069Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, Aichi Japan
| | - Nagi Mukae
- grid.260433.00000 0001 0728 1069Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, Aichi Japan
| | - Hirotaka Shoji
- grid.256115.40000 0004 1761 798XDivision of Systems Medical Science, Center for Medical Science, Fujita Health University, Toyoake, Aichi Japan
| | - Tsuyoshi Miyakawa
- grid.256115.40000 0004 1761 798XDivision of Systems Medical Science, Center for Medical Science, Fujita Health University, Toyoake, Aichi Japan
| | - Michiko Shirane
- grid.260433.00000 0001 0728 1069Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, Aichi Japan
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26
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Molecular machinery regulating organelle dynamics during axon growth and guidance. Semin Cell Dev Biol 2023; 133:3-9. [PMID: 35227625 DOI: 10.1016/j.semcdb.2022.02.019] [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: 10/26/2021] [Revised: 01/24/2022] [Accepted: 02/21/2022] [Indexed: 11/23/2022]
Abstract
Axon growth and guidance in the developing nervous system rely on intracellular membrane dynamics that involve endosome maturation and transport, as well as its regulated tethering to the endoplasmic reticulum (ER). Recent studies have identified several key molecules, such as protrudin, which plays a dynamic role at membrane contact sites between the ER and endosomes/lysosomes, and myosin Va, which acts as a sensor for ER-derived Ca2+ that triggers peri-ER membrane export. These molecules form different types of multiprotein complexes at the interface of organelles and, in response to their surrounding microenvironments, such as Ca2+ concentrations and lipid contents, regulate the directional movement of endosomal vesicles in extending axons. Here, we review the molecular mechanisms underlying membrane dynamics and inter-organelle interactions during neuronal morphogenesis.
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Loss of small GTPase Rab7 activation in prion infection negatively affects a feedback loop regulating neuronal cholesterol metabolism. J Biol Chem 2023; 299:102883. [PMID: 36623732 PMCID: PMC9926124 DOI: 10.1016/j.jbc.2023.102883] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Revised: 12/11/2022] [Accepted: 12/14/2022] [Indexed: 01/09/2023] Open
Abstract
Prion diseases are fatal and infectious neurodegenerative diseases that occur in humans and animals. They are caused by the misfolding of the cellular prion protein PrPc into the infectious isoform PrPSc. PrPSc accumulates mostly in endolysosomal vesicles of prion-infected cells, eventually causing neurodegeneration. In response to prion infection, elevated cholesterol levels and a reduction in membrane-attached small GTPase Rab7 have been observed in neuronal cells. Here, we investigated the molecular events causing an impaired Rab7 membrane attachment and the potential mechanistic link with elevated cholesterol levels in prion infection. We demonstrate that prion infection is associated with reduced levels of active Rab7 (Rab7.GTP) in persistently prion-infected neuronal cell lines, primary cerebellar granular neurons, and neurons in the brain of mice with terminal prion disease. In primary cerebellar granular neurons, levels of active Rab7 were increased during the very early stages of the prion infection prior to a significant decrease concomitant with PrPSc accumulation. The reduced activation of Rab7 in prion-infected neuronal cell lines is also associated with its reduced ubiquitination status, decreased interaction with its effector RILP, and altered lysosomal positioning. Consequently, the Rab7-mediated trafficking of low-density lipoprotein to lysosomes is delayed. This results in an impaired feedback regulation of cholesterol synthesis leading to an increase in cholesterol levels. Notably, transient overexpression of the constitutively active mutant of Rab7 rescues the delay in the low-density lipoprotein trafficking, hence reducing cholesterol levels and attenuating PrPSc propagation, demonstrating a mechanistic link between the loss of Rab7.GTP and elevated cholesterol levels.
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28
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Balla T, Gulyas G, Mandal A, Alvarez-Prats A, Niu Y, Kim YJ, Pemberton J. Roles of Phosphatidylinositol 4-Phosphorylation in Non-vesicular Cholesterol Trafficking. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1422:327-352. [PMID: 36988887 PMCID: PMC11135459 DOI: 10.1007/978-3-031-21547-6_12] [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] [Indexed: 03/30/2023]
Abstract
Cholesterol (Chol) is an essential component of all eukaryotic cell membranes that affects the function of numerous peripheral as well as integral membrane proteins. Chol is synthesized in the ER, but it is selectively enriched within the plasma membrane (PM) and other endomembranes, which requires Chol to cross the aqueous phase of the cytoplasm. In addition to the classical vesicular trafficking pathways that are known to facilitate the bulk transport of membrane intermediates, Chol is also transported via non-vesicular lipid transfer proteins that work primarily within specialized membrane contact sites. Some of these transport pathways work against established concentration gradients and hence require energy. Recent studies highlight the unique role of phosphoinositides (PPIns), and phosphatidylinositol 4-phosphate (PI4P) in particular, for the control of non-vesicular Chol transport. In this chapter, we will review the emerging connection between Chol, PPIns, and lipid transfer proteins that include the important family of oxysterol-binding protein related proteins, or ORPs.
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Affiliation(s)
- Tamas Balla
- Section on Molecular Signal Transduction, Program for Developmental Neuroscience, Eunice Kennedy Shriver NICHD, National Institutes of Health, Bethesda, MD, USA.
| | | | - Amrita Mandal
- Section on Molecular Signal Transduction, Program for Developmental Neuroscience, Eunice Kennedy Shriver NICHD, National Institutes of Health, Bethesda, MD, USA
| | - Alejandro Alvarez-Prats
- Section on Molecular Signal Transduction, Program for Developmental Neuroscience, Eunice Kennedy Shriver NICHD, National Institutes of Health, Bethesda, MD, USA
| | | | - Yeun Ju Kim
- Section on Molecular Signal Transduction, Program for Developmental Neuroscience, Eunice Kennedy Shriver NICHD, National Institutes of Health, Bethesda, MD, USA
| | - Joshua Pemberton
- Section on Molecular Signal Transduction, Program for Developmental Neuroscience, Eunice Kennedy Shriver NICHD, National Institutes of Health, Bethesda, MD, USA
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29
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Ghavami M, Fairn GD. Endoplasmic reticulum-Phagosome contact sites from the cradle to the grave. Front Cell Dev Biol 2022; 10:1074443. [PMID: 36619860 PMCID: PMC9813420 DOI: 10.3389/fcell.2022.1074443] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Accepted: 12/05/2022] [Indexed: 12/24/2022] Open
Abstract
Phagocytosis is a key component of the innate immune system used to ingest apoptotic cells and microorganisms for their destruction and recycling of macromolecules and the presentation of antigens to adaptive immune system cells. The newly formed vacuole or nascent phagosome undergoes a maturation process reminiscent of the classical endocytic maturation process, reaching a highly degradative phagolysosome stage before its tubulovesicular breakdown into lysosomes. The process is highly regulated and can be disrupted by various pathogenic organisms. The exchange of proteins, lipids, and other metabolites between organelles, including maturing phagosomes, is enabled by two processes, vesicular and non-vesicular transport at membrane contact sites (MCS). For decades the specific role(s) of the endoplasmic reticulum (ER) in phagocytosis has been the subject of much debate. In parallel, the last two decades have seen a burst in research on the numerous roles of ER contact sites and resident proteins in all aspects of organelle biology. Here, in this minireview, we describe ER-phagosome contact sites' functions from the early stages of particle engulfment to the phagolysosome dissolution into lysosomes. We also discuss several aspects of ER-phagosome contact sites that remain to be explored.
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Affiliation(s)
- Mahlegha Ghavami
- Department of Pathology, Dalhousie University, Halifax, NS, Canada
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, NS, Canada
| | - Gregory D. Fairn
- Department of Pathology, Dalhousie University, Halifax, NS, Canada
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, NS, Canada
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30
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Verweij FJ, Bebelman MP, George AE, Couty M, Bécot A, Palmulli R, Heiligenstein X, Sirés-Campos J, Raposo G, Pegtel DM, van Niel G. ER membrane contact sites support endosomal small GTPase conversion for exosome secretion. J Cell Biol 2022; 221:e202112032. [PMID: 36136097 PMCID: PMC9507465 DOI: 10.1083/jcb.202112032] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 08/11/2022] [Accepted: 09/02/2022] [Indexed: 12/13/2022] Open
Abstract
Exosomes are endosome-derived extracellular vesicles involved in intercellular communication. They are generated as intraluminal vesicles within endosomal compartments that fuse with the plasma membrane (PM). The molecular events that generate secretory endosomes and lead to the release of exosomes are not well understood. We identified a subclass of non-proteolytic endosomes at prelysosomal stage as the compartment of origin of CD63 positive exosomes. These compartments undergo a Rab7a/Arl8b/Rab27a GTPase cascade to fuse with the PM. Dynamic endoplasmic reticulum (ER)-late endosome (LE) membrane contact sites (MCS) through ORP1L have the distinct capacity to modulate this process by affecting LE motility, maturation state, and small GTPase association. Thus, exosome secretion is a multi-step process regulated by GTPase switching and MCS, highlighting the ER as a new player in exosome-mediated intercellular communication.
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Affiliation(s)
- Frederik J. Verweij
- Institute for Psychiatry and Neurosciences of Paris, Hopital Saint-Anne, Université de Paris, Institut national de la santé et de la recherche médicale, U1266, Paris, France
- Department of Cell Biology, Neurobiology and Biophysics, Utrecht University, Utrecht, The Netherlands
- Centre for Living Technologies, Alliance Eindhoven University of Technology, Wageningen University & Research, Utrecht University, University Medical Center Utrecht, The Netherlands
| | - Maarten P. Bebelman
- Institute for Psychiatry and Neurosciences of Paris, Hopital Saint-Anne, Université de Paris, Institut national de la santé et de la recherche médicale, U1266, Paris, France
- Department of Pathology, Cancer Center Amsterdam, Amsterdam University Medical Center, Amsterdam, The Netherlands
- Division of Medicinal Chemistry, Amsterdam Institute for Molecules Medicines and Systems, VU University, Amsterdam, The Netherlands
| | - Anna E. George
- Department of Cell Biology, Neurobiology and Biophysics, Utrecht University, Utrecht, The Netherlands
- Centre for Living Technologies, Alliance Eindhoven University of Technology, Wageningen University & Research, Utrecht University, University Medical Center Utrecht, The Netherlands
| | - Mickael Couty
- Institute for Psychiatry and Neurosciences of Paris, Hopital Saint-Anne, Université de Paris, Institut national de la santé et de la recherche médicale, U1266, Paris, France
| | - Anaïs Bécot
- Institute for Psychiatry and Neurosciences of Paris, Hopital Saint-Anne, Université de Paris, Institut national de la santé et de la recherche médicale, U1266, Paris, France
| | - Roberta Palmulli
- Institute for Psychiatry and Neurosciences of Paris, Hopital Saint-Anne, Université de Paris, Institut national de la santé et de la recherche médicale, U1266, Paris, France
| | - Xavier Heiligenstein
- Institut Curie, Paris Sciences & Lettres Research University, CNRS, UMR144, Paris, France
| | - Julia Sirés-Campos
- Institut Curie, Paris Sciences & Lettres Research University, CNRS, UMR144, Paris, France
| | - Graça Raposo
- Institut Curie, Paris Sciences & Lettres Research University, CNRS, UMR144, Paris, France
| | - Dirk Michiel Pegtel
- Department of Pathology, Cancer Center Amsterdam, Amsterdam University Medical Center, Amsterdam, The Netherlands
| | - Guillaume van Niel
- Institute for Psychiatry and Neurosciences of Paris, Hopital Saint-Anne, Université de Paris, Institut national de la santé et de la recherche médicale, U1266, Paris, France
- Groupe Hospitalier Universitaire Paris Psychiatrie et Neurosciences, Hôpital Sainte Anne, Paris, France
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31
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Zajac M, Modi S, Krishnan Y. The evolution of organellar calcium mapping technologies. Cell Calcium 2022; 108:102658. [PMID: 36274564 PMCID: PMC10224794 DOI: 10.1016/j.ceca.2022.102658] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 10/05/2022] [Accepted: 10/08/2022] [Indexed: 01/25/2023]
Abstract
Intracellular Ca2+ fluxes are dynamically controlled by the co-involvement of multiple organellar pools of stored Ca2+. Endolysosomes are emerging as physiologically critical, yet underexplored, sources and sinks of intracellular Ca2+. Delineating the role of organelles in Ca2+ signaling has relied on chemical fluorescent probes and electrophysiological strategies. However, the acidic endolysosomal environment presents unique issues, which preclude the use of traditional chemical reporter strategies to map lumenal Ca2+. Here, we broadly address the current state of knowledge about organellar Ca2+ pools. We then outline the application of traditional probes, and their sensing paradigms. We then discuss how a new generation of probes overcomes the limitations of traditional Ca2+probes, emphasizing their ability to offer critical insights into endolysosomal Ca2+, and its feedback with other organellar pools.
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Affiliation(s)
- Matthew Zajac
- Department of Chemistry, The University of Chicago, Chicago, Illinois, 60637, USA; Neuroscience Institute, The University of Chicago, Chicago, IL, 60637, USA
| | - Souvik Modi
- Esya Labs, Translation and Innovation Hub, Imperial College White City Campus, 84 Wood Lane, London, W12 0BZ, UK
| | - Yamuna Krishnan
- Department of Chemistry, The University of Chicago, Chicago, Illinois, 60637, USA; Neuroscience Institute, The University of Chicago, Chicago, IL, 60637, USA; Institute for Biophysical Dynamics, The University of Chicago, Chicago, Illinois, 60637, USA.
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32
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Ye H, Gao J, Liang Z, Lin Y, Yu Q, Huang S, Jiang L. Arabidopsis ORP2A mediates ER-autophagosomal membrane contact sites and regulates PI3P in plant autophagy. Proc Natl Acad Sci U S A 2022; 119:e2205314119. [PMID: 36252028 PMCID: PMC9618059 DOI: 10.1073/pnas.2205314119] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Accepted: 09/21/2022] [Indexed: 01/18/2023] Open
Abstract
Autophagy is an intracellular degradation system for cytoplasmic constituents which is mediated by the formation of a double-membrane organelle termed the autophagosome and its subsequent fusion with the lysosome/vacuole. The formation of the autophagosome requires membrane from the endoplasmic reticulum (ER) and is tightly regulated by a series of autophagy-related (ATG) proteins and lipids. However, how the ER contacts autophagosomes and regulates autophagy remain elusive in plants. In this study, we identified and demonstrated the roles of Arabidopsis oxysterol-binding protein-related protein 2A (ORP2A) in mediating ER-autophagosomal membrane contacts and autophagosome biogenesis. We showed that ORP2A localizes to both ER-plasma membrane contact sites (EPCSs) and autophagosomes, and that ORP2A interacts with both the ER-localized VAMP-associated protein (VAP) 27-1 and ATG8e on the autophagosomes to mediate the membrane contact sites (MCSs). In ORP2A artificial microRNA knockdown (KD) plants, seedlings display retarded growth and impaired autophagy levels. Both ATG1a and ATG8e accumulated and associated with the ER membrane in ORP2A KD lines. Moreover, ORP2A binds multiple phospholipids and shows colocalization with phosphatidylinositol 3-phosphate (PI3P) in vivo. Taken together, ORP2A mediates ER-autophagosomal MCSs and regulates autophagy through PI3P redistribution.
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Affiliation(s)
- Hao Ye
- School of Life Sciences, Centre for Cell & Developmental Biology, State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Hong Kong, China
| | - Jiayang Gao
- School of Life Sciences, Centre for Cell & Developmental Biology, State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Hong Kong, China
| | - Zizhen Liang
- School of Life Sciences, Centre for Cell & Developmental Biology, State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Hong Kong, China
| | - Youshun Lin
- School of Life Sciences, Centre for Cell & Developmental Biology, State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Hong Kong, China
| | - Qianyi Yu
- School of Life Sciences, Centre for Cell & Developmental Biology, State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Hong Kong, China
| | - Shuxian Huang
- School of Life Sciences, Centre for Cell & Developmental Biology, State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Hong Kong, China
| | - Liwen Jiang
- School of Life Sciences, Centre for Cell & Developmental Biology, State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Hong Kong, China
- The Chinese University of Hong Kong Shenzhen Research Institute, Shenzhen, 518057, China
- Institute of Plant Molecular Biology and Agricultural Biotechnology, The Chinese University of Hong Kong, Hong Kong, China
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33
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Wenzel EM, Elfmark LA, Stenmark H, Raiborg C. ER as master regulator of membrane trafficking and organelle function. J Cell Biol 2022; 221:e202205135. [PMID: 36108241 PMCID: PMC9481738 DOI: 10.1083/jcb.202205135] [Citation(s) in RCA: 44] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 08/16/2022] [Accepted: 08/22/2022] [Indexed: 12/13/2022] Open
Abstract
The endoplasmic reticulum (ER), which occupies a large portion of the cytoplasm, is the cell's main site for the biosynthesis of lipids and carbohydrate conjugates, and it is essential for folding, assembly, and biosynthetic transport of secreted proteins and integral membrane proteins. The discovery of abundant membrane contact sites (MCSs) between the ER and other membrane compartments has revealed that, in addition to its biosynthetic and secretory functions, the ER plays key roles in the regulation of organelle dynamics and functions. In this review, we will discuss how the ER regulates endosomes, lysosomes, autophagosomes, mitochondria, peroxisomes, and the Golgi apparatus via MCSs. Such regulation occurs via lipid and Ca2+ transfer and also via control of in trans dephosphorylation reactions and organelle motility, positioning, fusion, and fission. The diverse controls of other organelles via MCSs manifest the ER as master regulator of organelle biology.
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Affiliation(s)
- Eva Maria Wenzel
- Centre for Cancer Cell Reprogramming, Faculty of Medicine, University of Oslo, Oslo, Norway
- Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
| | - Liv Anker Elfmark
- Centre for Cancer Cell Reprogramming, Faculty of Medicine, University of Oslo, Oslo, Norway
- Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
| | - Harald Stenmark
- Centre for Cancer Cell Reprogramming, Faculty of Medicine, University of Oslo, Oslo, Norway
- Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
| | - Camilla Raiborg
- Centre for Cancer Cell Reprogramming, Faculty of Medicine, University of Oslo, Oslo, Norway
- Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
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34
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Scerra G, De Pasquale V, Scarcella M, Caporaso MG, Pavone LM, D'Agostino M. Lysosomal positioning diseases: beyond substrate storage. Open Biol 2022; 12:220155. [PMID: 36285443 PMCID: PMC9597170 DOI: 10.1098/rsob.220155] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Lysosomal storage diseases (LSDs) comprise a group of inherited monogenic disorders characterized by lysosomal dysfunctions due to undegraded substrate accumulation. They are caused by a deficiency in specific lysosomal hydrolases involved in cellular catabolism, or non-enzymatic proteins essential for normal lysosomal functions. In LSDs, the lack of degradation of the accumulated substrate and its lysosomal storage impairs lysosome functions resulting in the perturbation of cellular homeostasis and, in turn, the damage of multiple organ systems. A substantial number of studies on the pathogenesis of LSDs has highlighted how the accumulation of lysosomal substrates is only the first event of a cascade of processes including the accumulation of secondary metabolites and the impairment of cellular trafficking, cell signalling, autophagic flux, mitochondria functionality and calcium homeostasis, that significantly contribute to the onset and progression of these diseases. Emerging studies on lysosomal biology have described the fundamental roles of these organelles in a variety of physiological functions and pathological conditions beyond their canonical activity in cellular waste clearance. Here, we discuss recent advances in the knowledge of cellular and molecular mechanisms linking lysosomal positioning and trafficking to LSDs.
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Affiliation(s)
- Gianluca Scerra
- Department of Molecular Medicine and Medical Biotechnologies, University of Naples Federico II, Via Sergio Pansini 5, 80131 Naples, Italy
| | - Valeria De Pasquale
- Department of Veterinary Medicine and Animal Productions, University of Naples Federico II, Via Federico Delpino 1, 80137 Naples, Italy
| | - Melania Scarcella
- Department of Molecular Medicine and Medical Biotechnologies, University of Naples Federico II, Via Sergio Pansini 5, 80131 Naples, Italy
| | - Maria Gabriella Caporaso
- Department of Molecular Medicine and Medical Biotechnologies, University of Naples Federico II, Via Sergio Pansini 5, 80131 Naples, Italy
| | - Luigi Michele Pavone
- Department of Molecular Medicine and Medical Biotechnologies, University of Naples Federico II, Via Sergio Pansini 5, 80131 Naples, Italy
| | - Massimo D'Agostino
- Department of Molecular Medicine and Medical Biotechnologies, University of Naples Federico II, Via Sergio Pansini 5, 80131 Naples, Italy
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35
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Depta L, Whitmarsh-Everiss T, Laraia L. Structure, function and small molecule modulation of intracellular sterol transport proteins. Bioorg Med Chem 2022; 68:116856. [PMID: 35716590 DOI: 10.1016/j.bmc.2022.116856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Accepted: 05/23/2022] [Indexed: 11/02/2022]
Abstract
Intracellular sterol transport proteins (STPs) are crucial for maintaining cellular lipid homeostasis by regulating local sterol pools. Despite structural similarities in their sterol binding domains, STPs have different substrate specificities, intracellular localisation and biological functions. In this review, we highlight recent advances in the determination of STP structures and how this regulates their lipid specificities. Furthermore, we cover the important discoveries relating to the intracellular localisation of STPs, and the organelles between which lipid transport is carried out, giving rise to specific functions in health and disease. Finally, serendipitous and targeted efforts to identify small molecule modulators of STPs, as well as their ability to act as tool compounds and potential therapeutics, will be discussed.
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Affiliation(s)
- Laura Depta
- Department of Chemistry, Technical University of Denmark, Kemitorvet 207, 2800 Kgs Lyngby, Denmark
| | - Thomas Whitmarsh-Everiss
- Department of Chemistry, Technical University of Denmark, Kemitorvet 207, 2800 Kgs Lyngby, Denmark
| | - Luca Laraia
- Department of Chemistry, Technical University of Denmark, Kemitorvet 207, 2800 Kgs Lyngby, Denmark.
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36
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Linking Late Endosomal Cholesterol with Cancer Progression and Anticancer Drug Resistance. Int J Mol Sci 2022; 23:ijms23137206. [PMID: 35806209 PMCID: PMC9267071 DOI: 10.3390/ijms23137206] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 06/22/2022] [Accepted: 06/25/2022] [Indexed: 11/16/2022] Open
Abstract
Cancer cells undergo drastic metabolic adaptions to cover increased bioenergetic needs, contributing to resistance to therapies. This includes a higher demand for cholesterol, which often coincides with elevated cholesterol uptake from low-density lipoproteins (LDL) and overexpression of the LDL receptor in many cancers. This implies the need for cancer cells to accommodate an increased delivery of LDL along the endocytic pathway to late endosomes/lysosomes (LE/Lys), providing a rapid and effective distribution of LDL-derived cholesterol from LE/Lys to other organelles for cholesterol to foster cancer growth and spread. LDL-cholesterol exported from LE/Lys is facilitated by Niemann–Pick Type C1/2 (NPC1/2) proteins, members of the steroidogenic acute regulatory-related lipid transfer domain (StARD) and oxysterol-binding protein (OSBP) families. In addition, lysosomal membrane proteins, small Rab GTPases as well as scaffolding proteins, including annexin A6 (AnxA6), contribute to regulating cholesterol egress from LE/Lys. Here, we summarize current knowledge that links upregulated activity and expression of cholesterol transporters and related proteins in LE/Lys with cancer growth, progression and treatment outcomes. Several mechanisms on how cellular distribution of LDL-derived cholesterol from LE/Lys influences cancer cell behavior are reviewed, some of those providing opportunities for treatment strategies to reduce cancer progression and anticancer drug resistance.
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37
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Arif A, Khawar MB, Mehmood R, Abbasi MH, Sheikh N. Dichotomous role of autophagy in cancer. ASIAN BIOMED 2022; 16:111-120. [PMID: 37551378 PMCID: PMC10321184 DOI: 10.2478/abm-2022-0014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Autophagy is an evolutionary conserved catabolic process that plays physiological and pathological roles in a cell. Its effect on cellular metabolism, the proteome, and the number and quality of organelles, diversely holds the potential to alter cellular functions. It acts paradoxically in cancer as a tumor inhibitor as well as a tumor promoter. In the early stage of tumorigenesis, it prevents tumor initiation by the so-called "quality control mechanism" and suppresses cancer progression. For late-staged tumors that are exposed to stress, it acts as a vibrant process of degradation and recycling that promotes cancer by facilitating metastasis. Despite this dichotomy, the crucial role of autophagy is evident in cancer, and associated with mammalian targets of rapamycin (mTOR), p53, and Ras-derived major cancer networks. Irrespective of the controversy regarding autophagic manipulation, promotion and suppression of autophagy act as potential therapeutic targets in cancer treatment and may provide various anticancer therapies.
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Affiliation(s)
- Amin Arif
- Institute of Zoology, University of the Punjab, Lahore54000, Pakistan
| | - Muhammad Babar Khawar
- Institute of Zoology, University of the Punjab, Lahore54000, Pakistan
- Department of Zoology, University of Narowal, Narowal51750, Pakistan
| | - Rabia Mehmood
- Institute of Zoology, University of the Punjab, Lahore54000, Pakistan
| | - Muddasir Hassan Abbasi
- Institute of Zoology, University of the Punjab, Lahore54000, Pakistan
- Department of Zoology, University of Okara, Okara56130, Pakistan
| | - Nadeem Sheikh
- Institute of Zoology, University of the Punjab, Lahore54000, Pakistan
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38
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Yap CC, Winckler B. Spatial regulation of endosomes in growing dendrites. Dev Biol 2022; 486:5-14. [PMID: 35306006 PMCID: PMC10646839 DOI: 10.1016/j.ydbio.2022.03.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 02/21/2022] [Accepted: 03/13/2022] [Indexed: 01/19/2023]
Abstract
Many membrane proteins are highly enriched in either dendrites or axons. This non-uniform distribution is a critical feature of neuronal polarity and underlies neuronal function. The molecular mechanisms responsible for polarized distribution of membrane proteins has been studied for some time and many answers have emerged. A less well studied feature of neurons is that organelles are also frequently non-uniformly distributed. For instance, EEA1-positive early endosomes are somatodendritic whereas synaptic vesicles are axonal. In addition, some organelles are present in both axons and dendrites, but not distributed uniformly along the processes. One well known example are lysosomes which are abundant in the soma and proximal dendrite, but sparse in the distal dendrite and the distal axon. The mechanisms that determine the spatial distribution of organelles along dendrites are only starting to be studied. In this review, we will discuss the cell biological mechanisms of how the distribution of diverse sets of endosomes along the proximal-distal axis of dendrites might be regulated. In particular, we will focus on the regulation of bulk homeostatic mechanisms as opposed to local regulation. We posit that immature dendrites regulate organelle motility differently from mature dendrites in order to spatially organize dendrite growth, branching and sculpting.
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Phosphatidylinositol phosphates modulate interactions between the StarD4 sterol trafficking protein and lipid membranes. J Biol Chem 2022; 298:102058. [PMID: 35605664 PMCID: PMC9207681 DOI: 10.1016/j.jbc.2022.102058] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Revised: 05/12/2022] [Accepted: 05/18/2022] [Indexed: 11/22/2022] Open
Abstract
There is substantial evidence for extensive nonvesicular sterol transport in cells. For example, lipid transfer by the steroidogenic acute regulator-related proteins (StarD) containing a StarT domain has been shown to involve several pathways of nonvesicular trafficking. Among the soluble StarT domain–containing proteins, StarD4 is expressed in most tissues and has been shown to be an effective sterol transfer protein. However, it was unclear whether the lipid composition of donor or acceptor membranes played a role in modulating StarD4-mediated transport. Here, we used fluorescence-based assays to demonstrate a phosphatidylinositol phosphate (PIP)-selective mechanism by which StarD4 can preferentially extract sterol from liposome membranes containing certain PIPs (especially, PI(4,5)P2 and to a lesser degree PI(3,5)P2). Monophosphorylated PIPs and other anionic lipids had a smaller effect on sterol transport. This enhancement of transport was less effective when the same PIPs were present in the acceptor membranes. Furthermore, using molecular dynamics (MD) simulations, we mapped the key interaction sites of StarD4 with PIP-containing membranes and identified residues that are important for this interaction and for accelerated sterol transport activity. We show that StarD4 recognizes membrane-specific PIPs through specific interaction with the geometry of the PIP headgroup as well as the surrounding membrane environment. Finally, we also observed that StarD4 can deform membranes upon longer incubations. Taken together, these results suggest a mechanism by which PIPs modulate cholesterol transfer activity via StarD4.
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40
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Garcia M, Kumanski S, Elías-Villalobos A, Cazevieille C, Soulet C, Moriel-Carretero M. Nuclear ingression of cytoplasmic bodies accompanies a boost in autophagy. Life Sci Alliance 2022; 5:5/9/e202101160. [PMID: 35568434 PMCID: PMC9107791 DOI: 10.26508/lsa.202101160] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 05/02/2022] [Accepted: 05/02/2022] [Indexed: 12/28/2022] Open
Abstract
We describe a fully new remodeling event of the nuclear envelope surrounding the nucleolus: it partitions into its regular contact with the vacuole and a dramatic internalization of globular cytoplasmic portions within the nucleus. Membrane contact sites are functional nodes at which organelles reorganize metabolic pathways and adapt to changing cues. In Saccharomyces cerevisiae, the nuclear envelope subdomain surrounding the nucleolus, very plastic and prone to expansion, can establish contacts with the vacuole and be remodeled in response to various metabolic stresses. While using genotoxins with unrelated purposes, we serendipitously discovered a fully new remodeling event at this nuclear subdomain: the nuclear envelope partitions into its regular contact with the vacuole and a dramatic internalization within the nucleus. This leads to the nuclear engulfment of a globular, cytoplasmic portion. In spite of how we discovered it, the phenomenon is likely DNA damage-independent. We define lipids supporting negative curvature, such as phosphatidic acid and sterols, as bona fide drivers of this event. Mechanistically, we suggest that the engulfment of the cytoplasm triggers a suction phenomenon that enhances the docking of proton pump-containing vesicles with the vacuolar membrane, which we show matches a boost in autophagy. Thus, our findings unveil an unprecedented remodeling of the nucleolus-surrounding membranes with impact on metabolic adaptation.
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Affiliation(s)
- Manon Garcia
- Centre de Recherche en Biologie cellulaire de Montpellier (CRBM), Université de Montpellier, Centre National de la Recherche Scientifique, Montpellier, France
| | - Sylvain Kumanski
- Centre de Recherche en Biologie cellulaire de Montpellier (CRBM), Université de Montpellier, Centre National de la Recherche Scientifique, Montpellier, France
| | - Alberto Elías-Villalobos
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Virgen del Rocío-CSIC-Universidad de Sevilla, Sevilla, Spain.,Departamento de Genética, Universidad de Sevilla, Sevilla, Spain
| | - Chantal Cazevieille
- Institut de Neurosciences de Montpellier (INM), Université de Montpellier, INSERM, Montpellier, France
| | - Caroline Soulet
- Centre de Recherche en Biologie cellulaire de Montpellier (CRBM), Université de Montpellier, Centre National de la Recherche Scientifique, Montpellier, France
| | - María Moriel-Carretero
- Centre de Recherche en Biologie cellulaire de Montpellier (CRBM), Université de Montpellier, Centre National de la Recherche Scientifique, Montpellier, France
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41
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Loginov SV, Fermie J, Fokkema J, Agronskaia AV, De Heus C, Blab GA, Klumperman J, Gerritsen HC, Liv N. Correlative Organelle Microscopy: Fluorescence Guided Volume Electron Microscopy of Intracellular Processes. Front Cell Dev Biol 2022; 10:829545. [PMID: 35478966 PMCID: PMC9035751 DOI: 10.3389/fcell.2022.829545] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Accepted: 03/04/2022] [Indexed: 01/19/2023] Open
Abstract
Intracellular processes depend on a strict spatial and temporal organization of proteins and organelles. Therefore, directly linking molecular to nanoscale ultrastructural information is crucial in understanding cellular physiology. Volume or three-dimensional (3D) correlative light and electron microscopy (volume-CLEM) holds unique potential to explore cellular physiology at high-resolution ultrastructural detail across cell volumes. However, the application of volume-CLEM is hampered by limitations in throughput and 3D correlation efficiency. In order to address these limitations, we describe a novel pipeline for volume-CLEM that provides high-precision (<100 nm) registration between 3D fluorescence microscopy (FM) and 3D electron microscopy (EM) datasets with significantly increased throughput. Using multi-modal fiducial nanoparticles that remain fluorescent in epoxy resins and a 3D confocal fluorescence microscope integrated into a Focused Ion Beam Scanning Electron Microscope (FIB.SEM), our approach uses FM to target extremely small volumes of even single organelles for imaging in volume EM and obviates the need for post-correlation of big 3D datasets. We extend our targeted volume-CLEM approach to include live-cell imaging, adding information on the motility of intracellular membranes selected for volume-CLEM. We demonstrate the power of our approach by targeted imaging of rare and transient contact sites between the endoplasmic reticulum (ER) and lysosomes within hours rather than days. Our data suggest that extensive ER-lysosome and mitochondria-lysosome interactions restrict lysosome motility, highlighting the unique capabilities of our integrated CLEM pipeline for linking molecular dynamic data to high-resolution ultrastructural detail in 3D.
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Affiliation(s)
- Sergey V. Loginov
- Molecular Biophysics, Debye Institute for Nanomaterials Science, Utrecht University, Utrecht, Netherlands
| | - Job Fermie
- Molecular Biophysics, Debye Institute for Nanomaterials Science, Utrecht University, Utrecht, Netherlands
- Cell Biology, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
| | - Jantina Fokkema
- Molecular Biophysics, Debye Institute for Nanomaterials Science, Utrecht University, Utrecht, Netherlands
| | - Alexandra V. Agronskaia
- Molecular Biophysics, Debye Institute for Nanomaterials Science, Utrecht University, Utrecht, Netherlands
| | - Cilia De Heus
- Cell Biology, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
| | - Gerhard A. Blab
- Molecular Biophysics, Debye Institute for Nanomaterials Science, Utrecht University, Utrecht, Netherlands
| | - Judith Klumperman
- Cell Biology, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
| | - Hans C. Gerritsen
- Molecular Biophysics, Debye Institute for Nanomaterials Science, Utrecht University, Utrecht, Netherlands
| | - Nalan Liv
- Cell Biology, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
- *Correspondence: Nalan Liv,
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42
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Mechanisms regulating the sorting of soluble lysosomal proteins. Biosci Rep 2022; 42:231123. [PMID: 35394021 PMCID: PMC9109462 DOI: 10.1042/bsr20211856] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 04/05/2022] [Accepted: 04/07/2022] [Indexed: 11/17/2022] Open
Abstract
Lysosomes are key regulators of many fundamental cellular processes such as metabolism, autophagy, immune response, cell signalling and plasma membrane repair. These highly dynamic organelles are composed of various membrane and soluble proteins, which are essential for their proper functioning. The soluble proteins include numerous proteases, glycosidases and other hydrolases, along with activators, required for catabolism. The correct sorting of soluble lysosomal proteins is crucial to ensure the proper functioning of lysosomes and is achieved through the coordinated effort of many sorting receptors, resident ER and Golgi proteins, and several cytosolic components. Mutations in a number of proteins involved in sorting soluble proteins to lysosomes result in human disease. These can range from rare diseases such as lysosome storage disorders, to more prevalent ones, such as Alzheimer’s disease, Parkinson’s disease and others, including rare neurodegenerative diseases that affect children. In this review, we discuss the mechanisms that regulate the sorting of soluble proteins to lysosomes and highlight the effects of mutations in this pathway that cause human disease. More precisely, we will review the route taken by soluble lysosomal proteins from their translation into the ER, their maturation along the Golgi apparatus, and sorting at the trans-Golgi network. We will also highlight the effects of mutations in this pathway that cause human disease.
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43
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Maxson ME, Abbas YM, Wu JZ, Plumb JD, Grinstein S, Rubinstein JL. Detection and quantification of the vacuolar H+ATPase using the Legionella effector protein SidK. J Biophys Biochem Cytol 2022; 221:212963. [PMID: 35024770 PMCID: PMC8763849 DOI: 10.1083/jcb.202107174] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 12/14/2021] [Accepted: 12/21/2021] [Indexed: 12/11/2022] Open
Abstract
Acidification of secretory and endocytic organelles is required for proper receptor recycling, membrane traffic, protein degradation, and solute transport. Proton-pumping vacuolar H+ ATPases (V-ATPases) are responsible for this luminal acidification, which increases progressively as secretory and endocytic vesicles mature. An increasing density of V-ATPase complexes is thought to account for the gradual decrease in pH, but available reagents have not been sufficiently sensitive or specific to test this hypothesis. We introduce a new probe to localize and quantify V-ATPases. The probe is derived from SidK, a Legionella pneumophila effector protein that binds to the V-ATPase A subunit. We generated plasmids encoding fluorescent chimeras of SidK1-278, and labeled recombinant SidK1-278 with Alexa Fluor 568 to visualize and quantify V-ATPases with high specificity in live and fixed cells, respectively. We show that V-ATPases are acquired progressively during phagosome maturation, that they distribute in discrete membrane subdomains, and that their density in lysosomes depends on their subcellular localization.
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Affiliation(s)
- Michelle E Maxson
- Program in Cell Biology, The Hospital for Sick Children, Toronto, Canada
| | - Yazan M Abbas
- Program in Molecular Medicine, The Hospital for Sick Children Research Institute, Toronto, Canada
| | - Jing Ze Wu
- Program in Cell Biology, The Hospital for Sick Children, Toronto, Canada.,Department of Biochemistry, University of Toronto, Toronto, Canada
| | - Jonathan D Plumb
- Program in Cell Biology, The Hospital for Sick Children, Toronto, Canada
| | - Sergio Grinstein
- Program in Cell Biology, The Hospital for Sick Children, Toronto, Canada.,Department of Biochemistry, University of Toronto, Toronto, Canada
| | - John L Rubinstein
- Program in Molecular Medicine, The Hospital for Sick Children Research Institute, Toronto, Canada.,Department of Medical Biophysics, University of Toronto, Toronto, Canada.,Department of Biochemistry, University of Toronto, Toronto, Canada
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44
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Dickson EJ. Phosphoinositide transport and metabolism at membrane contact sites. Biochim Biophys Acta Mol Cell Biol Lipids 2022; 1867:159107. [PMID: 34995791 PMCID: PMC9662651 DOI: 10.1016/j.bbalip.2021.159107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 12/06/2021] [Accepted: 12/09/2021] [Indexed: 11/18/2022]
Abstract
Phosphoinositides are a family of signaling lipids that play a profound role in regulating protein function at the membrane-cytosol interface of all cellular membranes. Underscoring their importance, mutations or alterations in phosphoinositide metabolizing enzymes lead to host of developmental, neurodegenerative, and metabolic disorders that are devastating for human health. In addition to lipid enzymes, phosphoinositide metabolism is regulated and controlled at membrane contact sites (MCS). Regions of close opposition typically between the ER and other cellular membranes, MCS are non-vesicular lipid transport portals that engage in extensive communication to influence organelle homeostasis. This review focuses on lipid transport, specifically phosphoinositide lipid transport and metabolism at MCS.
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Affiliation(s)
- Eamonn J Dickson
- Department of Physiology and Membrane Biology, University of California, Davis, CA 95616, United States of America.
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45
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Lauzier A, Bossanyi MF, Larcher R, Nassari S, Ugrankar R, Henne WM, Jean S. Snazarus and its human ortholog SNX25 modulate autophagic flux. J Cell Sci 2022; 135:273525. [PMID: 34821359 DOI: 10.1242/jcs.258733] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Accepted: 11/12/2021] [Indexed: 12/26/2022] Open
Abstract
Macroautophagy, the degradation and recycling of cytosolic components in the lysosome, is an important cellular mechanism. It is a membrane-mediated process that is linked to vesicular trafficking events. The sorting nexin (SNX) protein family controls the sorting of a large array of cargoes, and various SNXs impact autophagy. To improve our understanding of their functions in vivo, we screened all Drosophila SNXs using inducible RNA interference in the fat body. Significantly, depletion of Snazarus (Snz) led to decreased autophagic flux. Interestingly, we observed altered distribution of Vamp7-positive vesicles with Snz depletion, and the roles of Snz were conserved in human cells. SNX25, the closest human ortholog to Snz, regulates both VAMP8 endocytosis and lipid metabolism. Through knockout-rescue experiments, we demonstrate that these activities are dependent on specific SNX25 domains and that the autophagic defects seen upon SNX25 loss can be rescued by ethanolamine addition. We also demonstrate the presence of differentially spliced forms of SNX14 and SNX25 in cancer cells. This work identifies a conserved role for Snz/SNX25 as a regulator of autophagic flux and reveals differential isoform expression between paralogs.
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Affiliation(s)
- Annie Lauzier
- Faculté de Médecine et des Sciences de la Santé, Département d'immunologie et de biologie cellulaire, Université de Sherbrooke, 3201, Rue Jean Mignault, Sherbrooke, Québec, CanadaJ1E 4K8
| | - Marie-France Bossanyi
- Faculté de Médecine et des Sciences de la Santé, Département d'immunologie et de biologie cellulaire, Université de Sherbrooke, 3201, Rue Jean Mignault, Sherbrooke, Québec, CanadaJ1E 4K8
| | - Raphaëlle Larcher
- Faculté de Médecine et des Sciences de la Santé, Département d'immunologie et de biologie cellulaire, Université de Sherbrooke, 3201, Rue Jean Mignault, Sherbrooke, Québec, CanadaJ1E 4K8
| | - Sonya Nassari
- Faculté de Médecine et des Sciences de la Santé, Département d'immunologie et de biologie cellulaire, Université de Sherbrooke, 3201, Rue Jean Mignault, Sherbrooke, Québec, CanadaJ1E 4K8
| | - Rupali Ugrankar
- Department of Cell Biology, UT Southwestern Medical Center, 6000 Hary Lines Boulevard, Dallas, TX 75390, USA
| | - W Mike Henne
- Department of Cell Biology, UT Southwestern Medical Center, 6000 Hary Lines Boulevard, Dallas, TX 75390, USA
| | - Steve Jean
- Faculté de Médecine et des Sciences de la Santé, Département d'immunologie et de biologie cellulaire, Université de Sherbrooke, 3201, Rue Jean Mignault, Sherbrooke, Québec, CanadaJ1E 4K8
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46
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Olkkonen VM, Ikonen E. Cholesterol transport in the late endocytic pathway: Roles of ORP family proteins. J Steroid Biochem Mol Biol 2022; 216:106040. [PMID: 34864207 DOI: 10.1016/j.jsbmb.2021.106040] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 11/24/2021] [Accepted: 12/01/2021] [Indexed: 12/29/2022]
Abstract
Oxysterol-binding protein (OSBP) homologues, designated ORP or OSBPL proteins, constitute one of the largest families of intracellular lipid-binding/transfer proteins (LTP). This review summarizes the mounting evidence that several members of this family participate in the machinery facilitating cholesterol trafficking in the late endocytic pathway. There are indications that OSBP, besides acting as a cholesterol/phosphatidylinositol 4-phosphate (PI4P) exchanger at the endoplasmic reticulum (ER)-trans-Golgi network (TGN) membrane contact sites (MCS), also exchanges these lipids at ER-lysosome (Lys) contacts, increasing Lys cholesterol content. The long isoform of ORP1 (ORP1L), which also targets ER-late endosome (LE)/Lys MCS, has the capacity to mediate cholesterol transport either from ER to LE or in the opposite direction. Moreover, it regulates the motility, positioning and fusion of LE as well as autophagic flux. ORP2, the closest relative of ORP1, is mainly cytosolic, but also targets PI(4,5)P2-rich endosomal compartments. Our latest data suggest that ORP2 transfers cholesterol from LE to recycling endosomes (RE) in exchange for PI(4,5)P2, thus stimulating the recruitment of focal adhesion kinase (FAK) on the RE and cell adhesion. FAK activates phosphoinositide kinase on the RE to enhance PI(4,5)P2 synthesis. ORP2 in turn transfers PI(4,5)P2 from RE to LE, thus regulating LE tubule formation and transport activity.
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Affiliation(s)
- Vesa M Olkkonen
- Minerva Foundation Institute for Medical Research, Helsinki, Finland; Department of Anatomy, Faculty of Medicine, University of Helsinki, Finland.
| | - Elina Ikonen
- Minerva Foundation Institute for Medical Research, Helsinki, Finland; Department of Anatomy, Faculty of Medicine, University of Helsinki, Finland; Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
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47
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Sekar M, Thirumurugan K. Autophagy: a molecular switch to regulate adipogenesis and lipolysis. Mol Cell Biochem 2022; 477:727-742. [PMID: 35022960 DOI: 10.1007/s11010-021-04324-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Accepted: 12/01/2021] [Indexed: 12/16/2022]
Abstract
Obesity is a complex epidemic disease caused by an imbalance of adipose tissue function that results in hyperglycemia, hyperlipidemia and insulin resistance which further develop into type 2 diabetes, cardiovascular disease and nonalcoholic fatty liver disease/nonalcoholic steatohepatitis. Adipose tissue is responsible for fat storage; white adipose tissue stores excess energy as fat for availability during starvation, whereas brown adipose tissue regulates thermogenesis through fat oxidation using uncoupling protein 1. However, hypertrophic fat storage results in inflammation and increase the chances for obesity which triggers autophagy genes and lipolytic enzymes to regulate lipid metabolism. Autophagy degrades cargo molecule with the help of lysosome and redistributes the energy back to the cell. Autophagy regulates adipocyte differentiation by modulating master regulators of adipogenesis. Adipogenesis is the process which stores excessive energy in the form of lipid droplets. Lipid droplets (LD) are dynamic cellular organelles that store toxic free-fatty acids into neutral triglycerides in adipose tissue. LD activates both lipolysis and lipophagy to degrade excess triglycerides. In obese tissue, autophagy is activated via pro-inflammatory cytokines produced by surplus fat stored in the adipose tissue. This review focused on the process of autophagy and adipogenesis and the transcription factors that regulate lipogenesis and lipolysis in the adipose tissue. We have also discussed about the importance of autophagic regulation within adipose tissue which controls the onset of obesity and its associated diseases.
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Affiliation(s)
- Mouliganesh Sekar
- Structural Biology Lab, Centre for Biomedical Research, School of Biosciences & Technology, Vellore Institute of Technology, Vellore, Tamil Nadu, India
| | - Kavitha Thirumurugan
- Structural Biology Lab, Centre for Biomedical Research, School of Biosciences & Technology, Vellore Institute of Technology, Vellore, Tamil Nadu, India.
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Arora A, Taskinen JH, Olkkonen VM. Coordination of inter-organelle communication and lipid fluxes by OSBP-related proteins. Prog Lipid Res 2022; 86:101146. [PMID: 34999137 DOI: 10.1016/j.plipres.2022.101146] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 12/10/2021] [Accepted: 01/03/2022] [Indexed: 12/31/2022]
Abstract
Oxysterol-binding protein (OSBP) and OSBP-related proteins (ORPs) constitute one of the largest families of lipid-binding/transfer proteins (LTPs) in eukaryotes. The current view is that many of them mediate inter-organelle lipid transfer over membrane contact sites (MCS). The transfer occurs in several cases in a 'counter-current' fashion: A lipid such as cholesterol or phosphatidylserine (PS) is transferred against its concentration gradient driven by transport of a phosphoinositide in the opposite direction. In this way ORPs are envisioned to maintain the distinct organelle lipid compositions, with impacts on multiple organelle functions. However, the functions of ORPs extend beyond lipid homeostasis to regulation of processes such as cell survival, proliferation and migration. Important expanding areas of mammalian ORP research include their roles in viral and bacterial infections, cancers, and neuronal function. The yeast OSBP homologue (Osh) proteins execute multifaceted functions in sterol and glycerophospholipid homeostasis, post-Golgi vesicle transport, phosphatidylinositol-4-phosphate, sphingolipid and target of rapamycin (TOR) signalling, and cell cycle control. These observations identify ORPs as lipid transporters and coordinators of signals with an unforeseen variety of cellular processes. Understanding their activities not only enlightens the biology of the living cell but also allows their employment as targets of new therapeutic approaches for disease.
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Affiliation(s)
- Amita Arora
- Minerva Foundation Institute for Medical Research, and Department of Anatomy, Faculty of Medicine, University of Helsinki, Finland
| | - Juuso H Taskinen
- Minerva Foundation Institute for Medical Research, and Department of Anatomy, Faculty of Medicine, University of Helsinki, Finland
| | - Vesa M Olkkonen
- Minerva Foundation Institute for Medical Research, and Department of Anatomy, Faculty of Medicine, University of Helsinki, Finland.
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Lee SJ, Choi Y, Kim HI, Moon HE, Paek SH, Kim TY, Ko S. Platycodin D inhibits autophagy and increases glioblastoma cell death via LDLR upregulation. Mol Oncol 2022; 16:250-268. [PMID: 33931944 PMCID: PMC8732342 DOI: 10.1002/1878-0261.12966] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Revised: 03/30/2021] [Accepted: 04/13/2021] [Indexed: 01/07/2023] Open
Abstract
Targeting autophagy is a promising therapeutic approach in cancer therapy. Here, we screened 30 traditional herbal medicines to identify novel autophagy regulators and found that Platycodon grandiflorus (PG) and platycodin D (PD), a triterpenoid saponin from PG, inhibited autophagy in glioblastoma multiforme (GBM) cells. Mechanistically, PD prevented lysosomal degradation and the fusion between autophagosomes and lysosomes by inducing sequestration of free cholesterol in lysosomes. The autophagy inhibitory effect of PD was mimicked by both genetic and pharmacological inhibition of Niemann-Pick C1 (NPC1), which exports low-density lipoprotein (LDL)-derived cholesterol from lysosomes. Moreover, PD promoted the uptake of exogenous LDL cholesterol via upregulation of LDL receptor (LDLR), leading to further accumulation of cholesterol within lysosomes and GBM cell death. Importantly, these phenomena were more pronounced in LDLR-overexpressing GBM cells than in normal astrocytes. Finally, blockade of cholesterol uptake by LDLR knockdown reversed the PD-induced inhibition of autophagy and GBM cell growth. Our study proposes that PD could be a potent anti-GBM drug by disrupting cholesterol trafficking and autophagy.
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Affiliation(s)
- Sol Ji Lee
- Department of Science in Korean MedicineGraduate SchoolKyung Hee UniversitySeoulKorea
- Center for Cognition and SocialityInstitute for Basic ScienceDaejeonKorea
| | - Yu‐Jeong Choi
- Department of Science in Korean MedicineGraduate SchoolKyung Hee UniversitySeoulKorea
| | - Hyo In Kim
- Department of Science in Korean MedicineGraduate SchoolKyung Hee UniversitySeoulKorea
| | - Hyo Eun Moon
- Department of NeurosurgeryAdvanced Institute of Convergence Technology (AICT)Cancer Research Institute, and Ischemic/Hypoxic Disease InstituteSeoul National University College of MedicineKorea
| | - Sun Ha Paek
- Department of NeurosurgeryAdvanced Institute of Convergence Technology (AICT)Cancer Research Institute, and Ischemic/Hypoxic Disease InstituteSeoul National University College of MedicineKorea
| | - Tai Young Kim
- Center for Cognition and SocialityInstitute for Basic ScienceDaejeonKorea
- Department of Preventive MedicineCollege of Korean MedicineKyung Hee UniversitySeoulKorea
| | - Seong‐Gyu Ko
- Department of Preventive MedicineCollege of Korean MedicineKyung Hee UniversitySeoulKorea
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Kors S, Costello JL, Schrader M. VAP Proteins - From Organelle Tethers to Pathogenic Host Interactors and Their Role in Neuronal Disease. Front Cell Dev Biol 2022; 10:895856. [PMID: 35756994 PMCID: PMC9213790 DOI: 10.3389/fcell.2022.895856] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 04/25/2022] [Indexed: 12/26/2022] Open
Abstract
Vesicle-associated membrane protein (VAMP)-associated proteins (VAPs) are ubiquitous ER-resident tail-anchored membrane proteins in eukaryotic cells. Their N-terminal major sperm protein (MSP) domain faces the cytosol and allows them to interact with a wide variety of cellular proteins. Therefore, VAP proteins are vital to many cellular processes, including organelle membrane tethering, lipid transfer, autophagy, ion homeostasis and viral defence. Here, we provide a timely overview of the increasing number of VAPA/B binding partners and discuss the role of VAPA/B in maintaining organelle-ER interactions and cooperation. Furthermore, we address how viruses and intracellular bacteria hijack VAPs and their binding partners to induce interactions between the host ER and pathogen-containing compartments and support pathogen replication. Finally, we focus on the role of VAP in human disease and discuss how mutated VAPB leads to the disruption of cellular homeostasis and causes amyotrophic lateral sclerosis.
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Affiliation(s)
- Suzan Kors
- *Correspondence: Suzan Kors, ; Michael Schrader,
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