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Berkane R, Ho-Xuan H, Glogger M, Sanz-Martinez P, Brunello L, Glaesner T, Kuncha SK, Holzhüter K, Cano-Franco S, Buonomo V, Cabrerizo-Poveda P, Balakrishnan A, Tascher G, Husnjak K, Juretschke T, Misra M, González A, Dötsch V, Grumati P, Heilemann M, Stolz A. The function of ER-phagy receptors is regulated through phosphorylation-dependent ubiquitination pathways. Nat Commun 2023; 14:8364. [PMID: 38102139 PMCID: PMC10724265 DOI: 10.1038/s41467-023-44101-5] [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: 07/18/2022] [Accepted: 11/30/2023] [Indexed: 12/17/2023] Open
Abstract
Selective autophagy of the endoplasmic reticulum (ER), known as ER-phagy, is an important regulator of ER remodeling and essential to maintain cellular homeostasis during environmental changes. We recently showed that members of the FAM134 family play a critical role during stress-induced ER-phagy. However, the mechanisms on how they are activated remain largely unknown. In this study, we analyze phosphorylation of FAM134 as a trigger of FAM134-driven ER-phagy upon mTOR (mechanistic target of rapamycin) inhibition. An unbiased screen of kinase inhibitors reveals CK2 to be essential for FAM134B- and FAM134C-driven ER-phagy after mTOR inhibition. Furthermore, we provide evidence that ER-phagy receptors are regulated by ubiquitination events and that treatment with E1 inhibitor suppresses Torin1-induced ER-phagy flux. Using super-resolution microscopy, we show that CK2 activity is essential for the formation of high-density FAM134B and FAM134C clusters. In addition, dense clustering of FAM134B and FAM134C requires phosphorylation-dependent ubiquitination of FAM134B and FAM134C. Treatment with the CK2 inhibitor SGC-CK2-1 or mutation of FAM134B and FAM134C phosphosites prevents ubiquitination of FAM134 proteins, formation of high-density clusters, as well as Torin1-induced ER-phagy flux. Therefore, we propose that CK2-dependent phosphorylation of ER-phagy receptors precedes ubiquitin-dependent activation of ER-phagy flux.
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Affiliation(s)
- Rayene Berkane
- Institute of Biochemistry II (IBC2), Faculty of Medicine, Goethe University, Frankfurt am Main, Germany
- Buchmann Institute for Molecular Life Sciences (BMLS), Goethe University, Frankfurt am Main, Germany
| | - Hung Ho-Xuan
- Institute of Biochemistry II (IBC2), Faculty of Medicine, Goethe University, Frankfurt am Main, Germany
- Buchmann Institute for Molecular Life Sciences (BMLS), Goethe University, Frankfurt am Main, Germany
| | - Marius Glogger
- Institute of Physical and Theoretical Chemistry, Goethe University, Frankfurt am Main, Germany
| | - Pablo Sanz-Martinez
- Institute of Biochemistry II (IBC2), Faculty of Medicine, Goethe University, Frankfurt am Main, Germany
- Buchmann Institute for Molecular Life Sciences (BMLS), Goethe University, Frankfurt am Main, Germany
| | - Lorène Brunello
- Institute of Biochemistry II (IBC2), Faculty of Medicine, Goethe University, Frankfurt am Main, Germany
- Buchmann Institute for Molecular Life Sciences (BMLS), Goethe University, Frankfurt am Main, Germany
| | - Tristan Glaesner
- Buchmann Institute for Molecular Life Sciences (BMLS), Goethe University, Frankfurt am Main, Germany
| | - Santosh Kumar Kuncha
- Institute of Biochemistry II (IBC2), Faculty of Medicine, Goethe University, Frankfurt am Main, Germany
- Buchmann Institute for Molecular Life Sciences (BMLS), Goethe University, Frankfurt am Main, Germany
| | - Katharina Holzhüter
- Institute of Biophysical Chemistry and Center for Biomolecular Magnetic Resonance, Goethe University, Frankfurt am Main, Germany
| | - Sara Cano-Franco
- Institute of Biochemistry II (IBC2), Faculty of Medicine, Goethe University, Frankfurt am Main, Germany
- Buchmann Institute for Molecular Life Sciences (BMLS), Goethe University, Frankfurt am Main, Germany
| | - Viviana Buonomo
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli, Italy
| | - Paloma Cabrerizo-Poveda
- Institute of Biochemistry II (IBC2), Faculty of Medicine, Goethe University, Frankfurt am Main, Germany
- Buchmann Institute for Molecular Life Sciences (BMLS), Goethe University, Frankfurt am Main, Germany
| | - Ashwin Balakrishnan
- Institute of Physical and Theoretical Chemistry, Goethe University, Frankfurt am Main, Germany
| | - Georg Tascher
- Institute of Biochemistry II (IBC2), Faculty of Medicine, Goethe University, Frankfurt am Main, Germany
| | - Koraljka Husnjak
- Institute of Biochemistry II (IBC2), Faculty of Medicine, Goethe University, Frankfurt am Main, Germany
| | | | - Mohit Misra
- Institute of Biochemistry II (IBC2), Faculty of Medicine, Goethe University, Frankfurt am Main, Germany
- Buchmann Institute for Molecular Life Sciences (BMLS), Goethe University, Frankfurt am Main, Germany
| | - Alexis González
- Institute of Biochemistry II (IBC2), Faculty of Medicine, Goethe University, Frankfurt am Main, Germany
| | - Volker Dötsch
- Institute of Biophysical Chemistry and Center for Biomolecular Magnetic Resonance, Goethe University, Frankfurt am Main, Germany
| | - Paolo Grumati
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli, Italy
- Department of Clinical Medicine and Surgery, Federico II University, Naples, Italy
| | - Mike Heilemann
- Institute of Physical and Theoretical Chemistry, Goethe University, Frankfurt am Main, Germany
| | - Alexandra Stolz
- Institute of Biochemistry II (IBC2), Faculty of Medicine, Goethe University, Frankfurt am Main, Germany.
- Buchmann Institute for Molecular Life Sciences (BMLS), Goethe University, Frankfurt am Main, Germany.
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2
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Qian X, He L, Yang J, Sun J, Peng X, Zhang Y, Mao Y, Zhang Y, Cui Y. UVRAG cooperates with cargo receptors to assemble the ER-phagy site. EMBO J 2023; 42:e113625. [PMID: 37902287 PMCID: PMC10690450 DOI: 10.15252/embj.2023113625] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Revised: 10/04/2023] [Accepted: 10/11/2023] [Indexed: 10/31/2023] Open
Abstract
ER-phagy is a selective autophagy process that targets specific regions of the endoplasmic reticulum (ER) for removal via lysosomal degradation. During cellular stress induced by starvation, cargo receptors concentrate at distinct ER-phagy sites (ERPHS) to recruit core autophagy proteins and initiate ER-phagy. However, the molecular mechanism responsible for ERPHS formation remains unclear. In our study, we discovered that the autophagy regulator UV radiation Resistance-Associated Gene (UVRAG) plays a crucial role in orchestrating the assembly of ERPHS. Upon starvation, UVRAG localizes to ERPHS and interacts with specific ER-phagy cargo receptors, such as FAM134B, ATL3, and RTN3L. UVRAG regulates the oligomerization of cargo receptors and facilitates the recruitment of Atg8 family proteins. Consequently, UVRAG promotes efficient ERPHS assembly and turnover of both ER sheets and tubules. Importantly, UVRAG-mediated ER-phagy contributes to the clearance of pathogenic proinsulin aggregates. Remarkably, the involvement of UVRAG in ER-phagy initiation is independent of its canonical function as a subunit of class III phosphatidylinositol 3-kinase complex II.
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Affiliation(s)
- Xuehong Qian
- Department of Neurosurgery, Medical Research Institute, Frontier Science Center for Immunology and MetabolismZhongnan Hospital of Wuhan University, Wuhan UniversityWuhanChina
| | - Lingang He
- Department of Neurosurgery, Medical Research Institute, Frontier Science Center for Immunology and MetabolismZhongnan Hospital of Wuhan University, Wuhan UniversityWuhanChina
| | - Jiejie Yang
- Department of Neurosurgery, Medical Research Institute, Frontier Science Center for Immunology and MetabolismZhongnan Hospital of Wuhan University, Wuhan UniversityWuhanChina
| | - Jiajia Sun
- Department of Neurosurgery, Medical Research Institute, Frontier Science Center for Immunology and MetabolismZhongnan Hospital of Wuhan University, Wuhan UniversityWuhanChina
| | - Xueying Peng
- Department of Neurosurgery, Medical Research Institute, Frontier Science Center for Immunology and MetabolismZhongnan Hospital of Wuhan University, Wuhan UniversityWuhanChina
| | - Yuting Zhang
- Department of Neurosurgery, Medical Research Institute, Frontier Science Center for Immunology and MetabolismZhongnan Hospital of Wuhan University, Wuhan UniversityWuhanChina
| | - Yizhou Mao
- Department of Rheumatology and Immunology, Medical Research Institute, Frontier Science Center for Immunology and MetabolismZhongnan Hospital of Wuhan University, Wuhan UniversityWuhanChina
| | - Ying Zhang
- Department of Rheumatology and Immunology, Medical Research Institute, Frontier Science Center for Immunology and MetabolismZhongnan Hospital of Wuhan University, Wuhan UniversityWuhanChina
| | - Yixian Cui
- Department of Neurosurgery, Medical Research Institute, Frontier Science Center for Immunology and MetabolismZhongnan Hospital of Wuhan University, Wuhan UniversityWuhanChina
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3
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Hill MA, Sykes AM, Mellick GD. ER-phagy in neurodegeneration. J Neurosci Res 2023; 101:1611-1623. [PMID: 37334842 DOI: 10.1002/jnr.25225] [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: 02/20/2023] [Revised: 05/11/2023] [Accepted: 05/31/2023] [Indexed: 06/21/2023]
Abstract
There are many cellular mechanisms implicated in the initiation and progression of neurodegenerative disorders. However, age and the accumulation of unwanted cellular products are a common theme underlying many neurodegenerative diseases including Alzheimer's disease, Parkinson's disease, and Niemann-Pick type C. Autophagy has been studied extensively in these diseases and various genetic risk factors have implicated disruption in autophagy homoeostasis as a major pathogenic mechanism. Autophagy is essential in the maintenance of neuronal homeostasis, as their postmitotic nature makes them particularly susceptible to the damage caused by accumulation of defective or misfolded proteins, disease-prone aggregates, and damaged organelles. Recently, autophagy of the endoplasmic reticulum (ER-phagy) has been identified as a novel cellular mechanism for regulating ER morphology and response to cellular stress. As neurodegenerative diseases are generally precipitated by cellular stressors such as protein accumulation and environmental toxin exposure the role of ER-phagy has begun to be investigated. In this review we discuss the current research in ER-phagy and its involvement in neurodegenerative diseases.
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Affiliation(s)
- Melissa A Hill
- Griffith Institute for Drug Discovery, Griffith University, Nathan, Queensland, Australia
| | - Alex M Sykes
- Griffith Institute for Drug Discovery, Griffith University, Nathan, Queensland, Australia
| | - George D Mellick
- Griffith Institute for Drug Discovery, Griffith University, Nathan, Queensland, Australia
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4
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Chino H, Mizushima N. ER-Phagy: Quality and Quantity Control of the Endoplasmic Reticulum by Autophagy. Cold Spring Harb Perspect Biol 2023; 15:cshperspect.a041256. [PMID: 35940904 PMCID: PMC9808580 DOI: 10.1101/cshperspect.a041256] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The endoplasmic reticulum (ER) is the largest organelle and has multiple roles in various cellular processes such as protein secretion, lipid synthesis, calcium storage, and organelle biogenesis. The quantity and quality of this organelle are controlled by the ubiquitin-proteasome system and autophagy (termed "ER-phagy"). ER-phagy is defined as the degradation of part of the ER by the vacuole or lysosomes, and there are at least two types of ER-phagy: macro-ER-phagy and micro-ER-phagy. In macro-ER-phagy, ER fragments are enclosed by autophagosomes, which is mediated by ER-phagy receptors. In micro-ER-phagy, a portion of the ER is engulfed directly by the vacuole or lysosomes. In these two pathways, some proteins in the ER lumen can be recognized selectively and subjected to ER-phagy. This review summarizes our current knowledge of ER-phagy, focusing on its membrane dynamics, molecular mechanisms, substrate specificity, and physiological significance.
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Affiliation(s)
- Haruka Chino
- Department of Biochemistry and Molecular Biology, Graduate School of Medicine, The University of Tokyo, Tokyo 113-0033, Japan
| | - Noboru Mizushima
- Department of Biochemistry and Molecular Biology, Graduate School of Medicine, The University of Tokyo, Tokyo 113-0033, Japan
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5
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Autophagy guards tendon homeostasis. Cell Death Dis 2022; 13:402. [PMID: 35461310 PMCID: PMC9035152 DOI: 10.1038/s41419-022-04824-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 03/28/2022] [Accepted: 04/04/2022] [Indexed: 02/06/2023]
Abstract
Tendons are vital collagen-dense specialized connective tissues transducing the force from skeletal muscle to the bone, thus enabling movement of the human body. Tendon cells adjust matrix turnover in response to physiological tissue loading and pathological overloading (tendinopathy). Nevertheless, the regulation of tendon matrix quality control is still poorly understood and the pathogenesis of tendinopathy is presently unsolved. Autophagy, the major mechanism of degradation and recycling of cellular components, plays a fundamental role in the homeostasis of several tissues. Here, we investigate the contribution of autophagy to human tendons’ physiology, and we provide in vivo evidence that it is an active process in human tendon tissue. We show that selective autophagy of the endoplasmic reticulum (ER-phagy), regulates the secretion of type I procollagen (PC1), the major component of tendon extracellular matrix. Pharmacological activation of autophagy by inhibition of mTOR pathway alters the ultrastructural morphology of three-dimensional tissue-engineered tendons, shifting collagen fibrils size distribution. Moreover, autophagy induction negatively affects the biomechanical properties of the tissue-engineered tendons, causing a reduction in mechanical strength under tensile force. Overall, our results provide the first evidence that autophagy regulates tendon homeostasis by controlling PC1 quality control, thus potentially playing a role in the development of injured tendons.
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6
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Lu J, Linares B, Xu Z, Rui YN. Mechanisms of FA-Phagy, a New Form of Selective Autophagy/Organellophagy. Front Cell Dev Biol 2021; 9:799123. [PMID: 34950664 PMCID: PMC8689057 DOI: 10.3389/fcell.2021.799123] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Accepted: 11/22/2021] [Indexed: 11/21/2022] Open
Abstract
Focal adhesions (FAs) are adhesive organelles that attach cells to the extracellular matrix and can mediate various biological functions in response to different environmental cues. Reduced FAs are often associated with enhanced cell migration and cancer metastasis. In addition, because FAs are essential for preserving vascular integrity, the loss of FAs leads to hemorrhages and is frequently observed in many vascular diseases such as intracranial aneurysms. For these reasons, FAs are an attractive therapeutic target for treating cancer or vascular diseases, two leading causes of death world-wide. FAs are controlled by both their formation and turnover. In comparison to the large body of literature detailing FA formation, the mechanisms of FA turnover are poorly understood. Recently, autophagy has emerged as a major mechanism to degrade FAs and stabilizing FAs by inhibiting autophagy has a beneficial effect on breast cancer metastasis, suggesting autophagy-mediated FA turnover is a promising drug target. Intriguingly, autophagy-mediated FA turnover is a selective process and the cargo receptors for recognizing FAs in this process are context-dependent, which ensures the degradation of specific cargo. This paper mainly reviews the cargo recognition mechanisms of FA-phagy (selective autophagy-mediated FA turnover) and its disease relevance. We seek to outline some new points of understanding that will facilitate further study of FA-phagy and precise therapeutic strategies for related diseases associated with aberrant FA functions.
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Affiliation(s)
- Jiayi Lu
- Department of Neurosurgery, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX, United States
| | - Bernard Linares
- Department of Neurosurgery, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX, United States
| | - Zhen Xu
- Department of Neurosurgery, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX, United States
| | - Yan-Ning Rui
- Department of Neurosurgery, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX, United States
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7
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Nieto-Torres JL, Durgan J, Franco-Romero A, Grumati P, Guardia CM, Leidal AM, Mandell MA, Towers CG, Wang F. The Autophagy, Inflammation and Metabolism Center international eSymposium - an early-career investigators' seminar series during the COVID-19 pandemic. J Cell Sci 2021; 134:jcs259268. [PMID: 34622922 PMCID: PMC8520733 DOI: 10.1242/jcs.259268] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Autophagy, Inflammation and Metabolism (AIM) Center organized a globally accessible, virtual eSymposium during the COVID-19 pandemic in 2020. The conference included presentations from scientific leaders, as well as a career discussion panel, and provided a much-needed platform for early-career investigators (ECIs) to showcase their research in autophagy. This Perspective summarizes the science presented by the ECIs during the event and discusses the lessons learned from a virtual meeting of this kind during the pandemic. The meeting was a learning experience for all involved, and the ECI participants herein offer their thoughts on the pros and cons of virtual meetings as a modality, either as standalone or hybrid events, with a view towards the post-pandemic world.
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Affiliation(s)
- Jose L Nieto-Torres
- Program of Development, Aging and Regeneration, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92037, USA
| | | | - Anais Franco-Romero
- Department of Biomedical Science, University of Padova, via U.Bassi 58b, 35121 Padova, Italy
- Venetian Institute of Molecular Medicine, via Orus 2, 35129 Padova, Italy
| | - Paolo Grumati
- Telethon Institute of Genetics and Medicine, 80078 Pozzuoli, Italy
| | - Carlos M Guardia
- Section on Intracellular Protein Trafficking, Neurosciences and Cellular and Structural Biology Division, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Andrew M Leidal
- Department of Pathology and Helen Diller Family Comprehensive Cancer Center, University of California San Francisco, San Francisco, CA 94143-0502, USA
| | - Michael A Mandell
- Department of Molecular Genetics and Microbiology, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, USA
- Autophagy, Inflammation and Metabolism Center of Biomedical Research Excellence, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, USA
| | - Christina G Towers
- The Salk Institute for Biological Studies, Molecular and Cell Biology Laboratory, 10010 N Torrey Pines Rd, La Jolla, CA 92037-1002, USA
| | - Fei Wang
- UT Southwestern Medical Center, Department of Cell Biology, Dallas, TX 75390-9039, USA
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8
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Qian H, Chao X, Williams J, Fulte S, Li T, Yang L, Ding WX. Autophagy in liver diseases: A review. Mol Aspects Med 2021; 82:100973. [PMID: 34120768 DOI: 10.1016/j.mam.2021.100973] [Citation(s) in RCA: 137] [Impact Index Per Article: 45.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Revised: 05/29/2021] [Accepted: 05/30/2021] [Indexed: 02/07/2023]
Abstract
The liver is a highly dynamic metabolic organ that plays critical roles in plasma protein synthesis, gluconeogenesis and glycogen storage, cholesterol metabolism and bile acid synthesis as well as drug/xenobiotic metabolism and detoxification. Research from the past decades indicate that autophagy, the cellular catabolic process mediated by lysosomes, plays an important role in maintaining cellular and metabolic homeostasis in the liver. Hepatic autophagy fluctuates with hormonal cues and the availability of nutrients that respond to fed and fasting states as well as circadian activities. Dysfunction of autophagy in liver parenchymal and non-parenchymal cells can lead to various liver diseases including non-alcoholic fatty liver diseases, alcohol associated liver disease, drug-induced liver injury, cholestasis, viral hepatitis and hepatocellular carcinoma. Therefore, targeting autophagy may be a potential strategy for treating these various liver diseases. In this review, we will discuss the current progress on the understanding of autophagy in liver physiology. We will also discuss several forms of selective autophagy in the liver and the molecular signaling pathways in regulating autophagy of different cell types and their implications in various liver diseases.
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Affiliation(s)
- Hui Qian
- Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, 3901 Rainbow Blvd., Kansas City, KS, 66160, USA
| | - Xiaojuan Chao
- Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, 3901 Rainbow Blvd., Kansas City, KS, 66160, USA
| | - Jessica Williams
- Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, 3901 Rainbow Blvd., Kansas City, KS, 66160, USA
| | - Sam Fulte
- Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, 3901 Rainbow Blvd., Kansas City, KS, 66160, USA
| | - Tiangang Li
- Harold Hamm Diabetes Center, Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA
| | - Ling Yang
- Department of Anatomy and Cell Biology, Fraternal Order of Eagles Diabetes Research Center, Pappajohn Biomedical Institute, University of Iowa Carver College of Medicine, Iowa City, IA, USA
| | - Wen-Xing Ding
- Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, 3901 Rainbow Blvd., Kansas City, KS, 66160, USA.
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9
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Cao T, Peng B, Zhou X, Cai J, Tang Y, Luo J, Xie H, Zhang J, Liu S. Integrated signaling system under endoplasmic reticulum stress in eukaryotic microorganisms. Appl Microbiol Biotechnol 2021; 105:4805-4818. [PMID: 34106312 DOI: 10.1007/s00253-021-11380-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 05/18/2021] [Accepted: 05/28/2021] [Indexed: 12/11/2022]
Abstract
The endoplasmic reticulum (ER) is a multifunctional organelle, which is crucial for correct folding and assembly of secretory and transmembrane proteins. Perturbations of ER function can cause ER stress. ER stress can activate the unfolded protein response (UPR) to cope with the accumulation of misfolded proteins and protein toxicity. UPR is a coordination system that regulates transcription and translation, leading to the recovery of ER homeostasis or cell death. However, cells have an integrated signaling system to cope with ER stress, which helps cells to restore and balance their ER function. The main components of this system are ER-associated degradation (ERAD), autophagy, hypoxia signaling, and mitochondrial biogenesis. If the balance cannot be restored, the imbalance will lead to cell death or apoptosis, or even to a series of diseases. In this review, a series of activities to restore the homeostasis of cells during ER stress are discussed. KEY POINTS: • Endoplasmic reticulum (ER) plays a key role in the biological process of cells. • Perturbations of ER function can cause ER stress, including the ER overload response (EOR), sterol-regulated cascade reaction, and the UPR. • Cells have an integrated signaling system (ERAD, autophagy, hypoxia signaling, and mitochondrial biogenesis) to cope with the adverse impact caused by ER stress.
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Affiliation(s)
- Ting Cao
- Department of Clinical Laboratory, The First Affiliated Hospital of University of South China, Hengyang, 421000, Hunan, China
| | - Binfeng Peng
- Department of Clinical Laboratory, The First Affiliated Hospital of University of South China, Hengyang, 421000, Hunan, China
| | - Xiangping Zhou
- Department of Clinical Laboratory, The First Affiliated Hospital of University of South China, Hengyang, 421000, Hunan, China
| | - Jialun Cai
- Department of Clinical Laboratory, The First Affiliated Hospital of University of South China, Hengyang, 421000, Hunan, China
| | - Yun Tang
- Department of Clinical Laboratory, The First Affiliated Hospital of University of South China, Hengyang, 421000, Hunan, China
| | - Jie Luo
- Department of Clinical Laboratory, The First Affiliated Hospital of University of South China, Hengyang, 421000, Hunan, China
| | - Haitao Xie
- Department of Clinical Laboratory, The First Affiliated Hospital of University of South China, Hengyang, 421000, Hunan, China
| | - Ji Zhang
- Department of Clinical Laboratory, The First Affiliated Hospital of University of South China, Hengyang, 421000, Hunan, China
| | - Shuangquan Liu
- Department of Clinical Laboratory, The First Affiliated Hospital of University of South China, Hengyang, 421000, Hunan, China.
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10
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Wang X, Fang Y, Huang Q, Xu P, Lenahan C, Lu J, Zheng J, Dong X, Shao A, Zhang J. An updated review of autophagy in ischemic stroke: From mechanisms to therapies. Exp Neurol 2021; 340:113684. [PMID: 33676918 DOI: 10.1016/j.expneurol.2021.113684] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Revised: 02/24/2021] [Accepted: 03/01/2021] [Indexed: 12/14/2022]
Abstract
Stroke is a leading cause of mortality and morbidity worldwide. Understanding the underlying mechanisms is important for developing effective therapies for treating stroke. Autophagy is a self-eating cellular catabolic pathway, which plays a crucial homeostatic role in the regulation of cell survival. Increasing evidence shows that autophagy, observed in various cell types, plays a critical role in brain pathology after ischemic stroke. Therefore, the regulation of autophagy can be a potential target for ischemic stroke treatment. In the present review, we summarize the recent progress that research has made regarding autophagy and ischemic stroke, including common signaling pathways, the role of autophagic subtypes (e.g. mitophagy, pexophagy, aggrephagy, endoplasmic reticulum-phagy, and lipophagy) in ischemic stroke, as well as the current methods for autophagy detection and potential therapeutic strategy.
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Affiliation(s)
- Xiaoyu Wang
- Department of Neurosurgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Yuanjian Fang
- Department of Neurosurgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Qingxia Huang
- Department of Echocardiography, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Penglei Xu
- Department of Neurosurgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Cameron Lenahan
- Center for Neuroscience Research, Loma Linda University School of Medicine, Loma Linda, CA, USA; Burrell College of Osteopathic Medicine, Las Cruces, NM, USA
| | - Jianan Lu
- Department of Neurosurgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Jingwei Zheng
- Department of Neurosurgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Xiao Dong
- Department of Neurosurgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Anwen Shao
- Department of Neurosurgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China.
| | - Jianmin Zhang
- Department of Neurosurgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China; Brain Research Institute, Zhejiang University, Hangzhou, Zhejiang, China; Collaborative Innovation Center for Brain Science, Zhejiang University, Hangzhou, Zhejiang, China.
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11
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Hüsler D, Steiner B, Welin A, Striednig B, Swart AL, Molle V, Hilbi H, Letourneur F. Dictyostelium lacking the single atlastin homolog Sey1 shows aberrant ER architecture, proteolytic processes and expansion of the Legionella-containing vacuole. Cell Microbiol 2021; 23:e13318. [PMID: 33583106 DOI: 10.1111/cmi.13318] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2021] [Revised: 02/04/2021] [Accepted: 02/05/2021] [Indexed: 02/06/2023]
Abstract
Dictyostelium discoideum Sey1 is the single ortholog of mammalian atlastin 1-3 (ATL1-3), which are large homodimeric GTPases mediating homotypic fusion of endoplasmic reticulum (ER) tubules. In this study, we generated a D. discoideum mutant strain lacking the sey1 gene and found that amoebae deleted for sey1 are enlarged, but grow and develop similarly to the parental strain. The ∆sey1 mutant amoebae showed an altered ER architecture, and the tubular ER network was partially disrupted without any major consequences for other organelles or the architecture of the secretory and endocytic pathways. Macropinocytic and phagocytic functions were preserved; however, the mutant amoebae exhibited cumulative defects in lysosomal enzymes exocytosis, intracellular proteolysis, and cell motility, resulting in impaired growth on bacterial lawns. Moreover, ∆sey1 mutant cells showed a constitutive activation of the unfolded protein response pathway (UPR), but they still readily adapted to moderate levels of ER stress, while unable to cope with prolonged stress. In D. discoideum ∆sey1 the formation of the ER-associated compartment harbouring the bacterial pathogen Legionella pneumophila was also impaired. In the mutant amoebae, the ER was less efficiently recruited to the "Legionella-containing vacuole" (LCV), the expansion of the pathogen vacuole was inhibited at early stages of infection and intracellular bacterial growth was reduced. In summary, our study establishes a role of D. discoideum Sey1 in ER architecture, proteolysis, cell motility and intracellular replication of L. pneumophila.
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Affiliation(s)
- Dario Hüsler
- Institute of Medical Microbiology, University of Zürich, Zürich, Switzerland
| | - Bernhard Steiner
- Institute of Medical Microbiology, University of Zürich, Zürich, Switzerland
| | - Amanda Welin
- Division of Inflammation and Infection, Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden
| | - Bianca Striednig
- Institute of Medical Microbiology, University of Zürich, Zürich, Switzerland
| | - A Leoni Swart
- Institute of Medical Microbiology, University of Zürich, Zürich, Switzerland
| | - Virginie Molle
- Laboratory of Pathogen Host Interactions, Université de Montpellier, CNRS, INSERM, Montpellier, France
| | - Hubert Hilbi
- Institute of Medical Microbiology, University of Zürich, Zürich, Switzerland
| | - François Letourneur
- Laboratory of Pathogen Host Interactions, Université de Montpellier, CNRS, INSERM, Montpellier, France
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12
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Kang JA, Jeon YJ. How Is the Fidelity of Proteins Ensured in Terms of Both Quality and Quantity at the Endoplasmic Reticulum? Mechanistic Insights into E3 Ubiquitin Ligases. Int J Mol Sci 2021; 22:ijms22042078. [PMID: 33669844 PMCID: PMC7923238 DOI: 10.3390/ijms22042078] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 02/16/2021] [Accepted: 02/16/2021] [Indexed: 02/06/2023] Open
Abstract
The endoplasmic reticulum (ER) is an interconnected organelle that plays fundamental roles in the biosynthesis, folding, stabilization, maturation, and trafficking of secretory and transmembrane proteins. It is the largest organelle and critically modulates nearly all aspects of life. Therefore, in the endoplasmic reticulum, an enormous investment of resources, including chaperones and protein folding facilitators, is dedicated to adequate protein maturation and delivery to final destinations. Unfortunately, the folding and assembly of proteins can be quite error-prone, which leads to the generation of misfolded proteins. Notably, protein homeostasis, referred to as proteostasis, is constantly exposed to danger by flows of misfolded proteins and subsequent protein aggregates. To maintain proteostasis, the ER triages and eliminates terminally misfolded proteins by delivering substrates to the ubiquitin–proteasome system (UPS) or to the lysosome, which is termed ER-associated degradation (ERAD) or ER-phagy, respectively. ERAD not only eliminates misfolded or unassembled proteins via protein quality control but also fine-tunes correctly folded proteins via protein quantity control. Intriguingly, the diversity and distinctive nature of E3 ubiquitin ligases determine efficiency, complexity, and specificity of ubiquitination during ERAD. ER-phagy utilizes the core autophagy machinery and eliminates ERAD-resistant misfolded proteins. Here, we conceptually outline not only ubiquitination machinery but also catalytic mechanisms of E3 ubiquitin ligases. Further, we discuss the mechanistic insights into E3 ubiquitin ligases involved in the two guardian pathways in the ER, ERAD and ER-phagy. Finally, we provide the molecular mechanisms by which ERAD and ER-phagy conduct not only protein quality control but also protein quantity control to ensure proteostasis and subsequent organismal homeostasis.
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Affiliation(s)
- Ji An Kang
- Department of Biochemistry, College of Medicine, Chungnam National University, Daejeon 35015, Korea;
- Department of Medical Science, College of Medicine, Chungnam National University, Daejeon 35015, Korea
| | - Young Joo Jeon
- Department of Biochemistry, College of Medicine, Chungnam National University, Daejeon 35015, Korea;
- Department of Medical Science, College of Medicine, Chungnam National University, Daejeon 35015, Korea
- Correspondence:
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13
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Mende H, Müller S. Surveillance of nucleolar homeostasis and ribosome maturation by autophagy and the ubiquitin-proteasome system. Matrix Biol 2021; 100-101:30-38. [PMID: 33556475 DOI: 10.1016/j.matbio.2021.02.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 02/01/2021] [Accepted: 02/02/2021] [Indexed: 12/11/2022]
Abstract
The nucleolus functions as the cellular hub for the initiation and early steps of ribosome biogenesis. Ribosomes are key components of the translation machinery and, accordingly, their abundance needs to be adjusted to the cellular energy status. Further, to ensure translational fidelity, the integrity and quality of ribosomes needs to be monitored under conditions of cellular stress. Stressful insults, such as nutrient, genotoxic or proteotoxic stress, interfere with ribosome biogenesis and activate a cellular response referred to as nucleolar stress. This nucleolar stress response typically affects nucleolar integrity and is intricately linked to the activation of protein quality control pathways, including (i) the ubiquitin proteasome system (UPS) and (ii) the autophagy machinery, to restore cellular proteostasis. Here we will review some key features of the nucleolar stress response with a particular focus on the role of the UPS and autophagy in this process.
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Affiliation(s)
- Hannah Mende
- Institute of Biochemistry II, Goethe University, Medical School, Theodor-Stern-Kai 7, 60590 Frankfurt, Germany
| | - Stefan Müller
- Institute of Biochemistry II, Goethe University, Medical School, Theodor-Stern-Kai 7, 60590 Frankfurt, Germany.
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14
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Perrotta I. ER-phagy in human atherosclerosis: an exploratory ultrastructural study. Ultrastruct Pathol 2020; 44:489-495. [PMID: 33118423 DOI: 10.1080/01913123.2020.1840468] [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: 10/23/2022]
Abstract
Autophagy is a vacuolar self-digesting mechanism responsible for the removal of damaged organelles, indigestible aggregates, and nonfunctional long-lived proteins by lysosome. Autophagy is dynamically connected to the endoplasmic reticulum (ER) in several ways. It is capable to counteract the possible harmful effects linked to the impairment of protein folding in the ER; the ER has been proposed as the source for autophagosomal membranes. Also, the ER itself can undergo a selective form of autophagy (called ER-phagy) which ensures the maintenance of ER's morphology and function. Autophagy has been widely investigated in the cardiovascular system however there is no evidence to date regarding the occurrence of ER-phagy into the blood vessel wall. This study has been undertaken to explore the existence of this selective control mechanism in the cells of human atherosclerotic plaques. Transmission Electron Microscopy (TEM) analysis revealed that in the plaque cells the smooth ER profiles reorganized into concentric whorls and closely packed membranes arranged in curved and parallel arrays. Circular, often ring-shaped, ER membranes studded with ribosomes and enclosed in a sequestering vesicle have been also frequently observed. This preliminary study demonstrates the existence of a distinct machinery for the specific turnover of ER membranes in human atherosclerosis and provides the first ultrastructural description of ER-phagy in the diseased vascular tissue. These results may open new perspectives for future investigation in the cardiovascular field.
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Affiliation(s)
- Ida Perrotta
- Centre for Microscopy and Microanalysis, Transmission Electron Microscopy Laboratory - Department of Biology, Ecology and Earth Sciences (Di.B.E.S.T.), University of Calabria , Cosenza, Italy
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15
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Zielke S, Kardo S, Zein L, Mari M, Covarrubias-Pinto A, Kinzler MN, Meyer N, Stolz A, Fulda S, Reggiori F, Kögel D, van Wijk S. ATF4 links ER stress with reticulophagy in glioblastoma cells. Autophagy 2020; 17:2432-2448. [PMID: 33111629 DOI: 10.1080/15548627.2020.1827780] [Citation(s) in RCA: 68] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Selective degradation of the endoplasmic reticulum (ER; reticulophagy) is a type of autophagy involved in the removal of ER fragments. So far, amino acid starvation as well as ER stress have been described as inducers of reticulophagy, which in turn restores cellular energy levels and ER homeostasis. Here, we explored the autophagy-inducing mechanisms that underlie the autophagic cell death (ACD)-triggering compound loperamide (LOP) in glioblastoma cells. Interestingly, LOP triggers upregulation of the transcription factor ATF4, which is accompanied by the induction of additional ER stress markers. Notably, knockout of ATF4 significantly attenuated LOP-induced autophagy and ACD. Functionally, LOP also specifically induces the engulfment of large ER fragments within autophagosomes and lysosomes as determined by electron and fluorescence microscopy. LOP-induced reticulophagy and cell death are predominantly mediated through the reticulophagy receptor RETREG1/FAM134B and, to a lesser extent, TEX264, confirming that reticulophagy receptors can promote ACD. Strikingly, apart from triggering LOP-induced autophagy and ACD, ATF4 is also required for LOP-induced reticulophagy. These observations highlight a key role for ATF4, RETREG1 and TEX264 in response to LOP-induced ER stress, reticulophagy and ACD, and establish a novel mechanistic link between ER stress and reticulophagy, with possible implications for additional models of drug-induced ER stress.Abbreviations: ACD: autophagic cell death; ATF6: activating transcription factor 6; ATL3: atlastin 3; BafA1: bafilomycin A1; CCPG1: cell cycle progression gene 1; co-IP: co-immunoprecipitation; DDIT3/CHOP: DNA damage inducible transcript 3; ER: endoplasmic reticulum; EIF2A/eIF2α: eukaryotic translation initiation factor 2A; EIF2AK3/PERK: eukaryotic translation initiation factor 2 alpha kinase 3; ERN1/IRE1α: endoplasmic reticulum to nucleus signaling 1; GABARAP: GABA type A receptor-associated protein; GBM: glioblastoma multiforme; HSPA5/BiP: heat shock protein family (Hsp70) member 5; LOP: loperamide; MAP1LC3/LC3: microtubule-associated protein 1 light chain 3; RETREG1/FAM134B: reticulophagy regulator 1; RTN3L: reticulon 3 long; SEC62: SEC62 homolog, protein translocation factor; TEX264: testis-expressed 264, reticulophagy receptor; UPR: unfolded protein response.
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Affiliation(s)
- Svenja Zielke
- Institute for Experimental Cancer Research in Pediatrics, Goethe-University Frankfurt, Germany
| | - Simon Kardo
- Institute for Experimental Cancer Research in Pediatrics, Goethe-University Frankfurt, Germany
| | - Laura Zein
- Institute for Experimental Cancer Research in Pediatrics, Goethe-University Frankfurt, Germany
| | - Muriel Mari
- Department of Cell Biology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Adriana Covarrubias-Pinto
- Institute of Biochemistry II, Goethe-University - Medical Faculty, University Hospital, Frankfurt, Germany
| | - Maximilian N Kinzler
- Institute for Experimental Cancer Research in Pediatrics, Goethe-University Frankfurt, Germany.,German Cancer Consortium (DKTK), Partner Site Frankfurt, Germany
| | - Nina Meyer
- Experimental Neurosurgery, Goethe-University Hospital, Frankfurt, Germany
| | - Alexandra Stolz
- Institute of Biochemistry II, Goethe-University - Medical Faculty, University Hospital, Frankfurt, Germany.,Buchmann Institute for Molecular Life Sciences, Goethe-University Frankfurt, Frankfurt, Germany
| | - Simone Fulda
- Institute for Experimental Cancer Research in Pediatrics, Goethe-University Frankfurt, Germany.,German Cancer Consortium (DKTK), Partner Site Frankfurt, Germany.,German Cancer Research Centre (DKFZ), Heidelberg, Germany
| | - Fulvio Reggiori
- Department of Cell Biology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Donat Kögel
- German Cancer Consortium (DKTK), Partner Site Frankfurt, Germany.,Experimental Neurosurgery, Goethe-University Hospital, Frankfurt, Germany
| | - Sjoerd van Wijk
- Institute for Experimental Cancer Research in Pediatrics, Goethe-University Frankfurt, Germany
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16
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Vainshtein A, Grumati P. Selective Autophagy by Close Encounters of the Ubiquitin Kind. Cells 2020; 9:cells9112349. [PMID: 33114389 PMCID: PMC7693032 DOI: 10.3390/cells9112349] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 10/19/2020] [Accepted: 10/21/2020] [Indexed: 12/11/2022] Open
Abstract
Autophagy, a bulk degradation process within eukaryotic cells, is responsible for cellular turnover and nutrient liberation during starvation. Increasing evidence indicate that this process can be extremely discerning. Selective autophagy segregates and eliminates protein aggregates, damaged organelles, and invading organisms. The specificity of this process is largely mediated by post-translational modifications (PTMs), which are recognized by autophagy receptors. These receptors grant autophagy surgical precision in cargo selection, where only tagged substrates are engulfed within autophagosomes and delivered to the lysosome for proteolytic breakdown. A growing number of selective autophagy receptors have emerged including p62, NBR1, OPTN, NDP52, TAX1BP1, TOLLIP, and more continue to be uncovered. The most well-documented PTM is ubiquitination and selective autophagy receptors are equipped with a ubiquitin binding domain and an LC3 interacting region which allows them to physically bridge cargo to autophagosomes. Here, we review the role of ubiquitin and ubiquitin-like post-translational modifications in various types of selective autophagy.
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Affiliation(s)
| | - Paolo Grumati
- Telethon Institute of Genetics and Medicine, 80078 Pozzuoli (NA), Italy
- Correspondence:
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17
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Markaki M, Tavernarakis N. Autophagy mechanisms and roles: recent advances and implications. FEBS J 2020; 287:5024-5026. [PMID: 33089945 DOI: 10.1111/febs.15573] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Accepted: 09/18/2020] [Indexed: 12/23/2022]
Abstract
Autophagy is the main catabolic process by which cells recycle cytoplasmic components and superfluous or damaged organelles to preserve metabolic homeostasis under normal conditions and promote survival under stress. As a tightly regulated and dynamic process, autophagy has critical roles in development and cell differentiation, immune function, organismal health and lifespan. Accumulating findings suggest that defective or dysregulated autophagy accelerates ageing and increases susceptibility to diseases, such as neurodegenerative disorders and cancer, among others. This virtual issue of the FEBS Journal on Autophagy includes a collection of articles that present recent advances on the regulation of autophagy and provide a view of its complex roles in physiological and pathological contexts.
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Affiliation(s)
- Maria Markaki
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Crete, Greece
| | - Nektarios Tavernarakis
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Crete, Greece.,Department of Basic Sciences, School of Medicine, University of Crete, Heraklion, Crete, Greece
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18
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Stephani M, Picchianti L, Gajic A, Beveridge R, Skarwan E, Sanchez de Medina Hernandez V, Mohseni A, Clavel M, Zeng Y, Naumann C, Matuszkiewicz M, Turco E, Loefke C, Li B, Dürnberger G, Schutzbier M, Chen HT, Abdrakhmanov A, Savova A, Chia KS, Djamei A, Schaffner I, Abel S, Jiang L, Mechtler K, Ikeda F, Martens S, Clausen T, Dagdas Y. A cross-kingdom conserved ER-phagy receptor maintains endoplasmic reticulum homeostasis during stress. eLife 2020; 9:e58396. [PMID: 32851973 PMCID: PMC7515635 DOI: 10.7554/elife.58396] [Citation(s) in RCA: 124] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Accepted: 08/26/2020] [Indexed: 12/15/2022] Open
Abstract
Eukaryotes have evolved various quality control mechanisms to promote proteostasis in the endoplasmic reticulum (ER). Selective removal of certain ER domains via autophagy (termed as ER-phagy) has emerged as a major quality control mechanism. However, the degree to which ER-phagy is employed by other branches of ER-quality control remains largely elusive. Here, we identify a cytosolic protein, C53, that is specifically recruited to autophagosomes during ER-stress, in both plant and mammalian cells. C53 interacts with ATG8 via a distinct binding epitope, featuring a shuffled ATG8 interacting motif (sAIM). C53 senses proteotoxic stress in the ER lumen by forming a tripartite receptor complex with the ER-associated ufmylation ligase UFL1 and its membrane adaptor DDRGK1. The C53/UFL1/DDRGK1 receptor complex is activated by stalled ribosomes and induces the degradation of internal or passenger proteins in the ER. Consistently, the C53 receptor complex and ufmylation mutants are highly susceptible to ER stress. Thus, C53 forms an ancient quality control pathway that bridges selective autophagy with ribosome-associated quality control in the ER.
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Affiliation(s)
- Madlen Stephani
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna BioCenter (VBC)ViennaAustria
| | - Lorenzo Picchianti
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna BioCenter (VBC)ViennaAustria
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC)ViennaAustria
| | - Alexander Gajic
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna BioCenter (VBC)ViennaAustria
| | - Rebecca Beveridge
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC)ViennaAustria
| | - Emilio Skarwan
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna BioCenter (VBC)ViennaAustria
| | | | - Azadeh Mohseni
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna BioCenter (VBC)ViennaAustria
| | - Marion Clavel
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna BioCenter (VBC)ViennaAustria
| | - Yonglun Zeng
- School of Life Sciences, Centre for Cell and Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, School of Life Sciences, New TerritoriesShatinChina
| | - Christin Naumann
- Department of Molecular Signal Processing, Leibniz Institute of Plant BiochemistryHalleGermany
| | - Mateusz Matuszkiewicz
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna BioCenter (VBC)ViennaAustria
- Department of Plant Genetics, Breeding and Biotechnology, Warsaw University of Life Sciences-SGGWWarsawPoland
| | - Eleonora Turco
- Department of Biochemistry and Cell Biology, Max Perutz Labs, University of Vienna, Vienna BioCenter (VBC)ViennaAustria
| | - Christian Loefke
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna BioCenter (VBC)ViennaAustria
| | - Baiying Li
- School of Life Sciences, Centre for Cell and Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, School of Life Sciences, New TerritoriesShatinChina
| | - Gerhard Dürnberger
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna BioCenter (VBC)ViennaAustria
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC)ViennaAustria
| | - Michael Schutzbier
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna BioCenter (VBC)ViennaAustria
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC)ViennaAustria
| | - Hsiao Tieh Chen
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna BioCenter (VBC)ViennaAustria
- School of Life Sciences, Centre for Cell and Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, School of Life Sciences, New TerritoriesShatinChina
| | - Alibek Abdrakhmanov
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna BioCenter (VBC)ViennaAustria
| | - Adriana Savova
- Department of Biochemistry and Cell Biology, Max Perutz Labs, University of Vienna, Vienna BioCenter (VBC)ViennaAustria
| | - Khong-Sam Chia
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna BioCenter (VBC)ViennaAustria
| | - Armin Djamei
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna BioCenter (VBC)ViennaAustria
| | - Irene Schaffner
- BOKU Core Facility Biomolecular & Cellular Analysis, University of Natural Resources and Life SciencesViennaAustria
| | - Steffen Abel
- Department of Molecular Signal Processing, Leibniz Institute of Plant BiochemistryHalleGermany
| | - Liwen Jiang
- School of Life Sciences, Centre for Cell and Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, School of Life Sciences, New TerritoriesShatinChina
| | - Karl Mechtler
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna BioCenter (VBC)ViennaAustria
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC)ViennaAustria
| | - Fumiyo Ikeda
- Department of Molecular and Cellular Biology, Medical Institute of Bioregulation, Kyushu UniversityFukuokaJapan
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna BioCenter (VBC)ViennaAustria
| | - Sascha Martens
- Department of Biochemistry and Cell Biology, Max Perutz Labs, University of Vienna, Vienna BioCenter (VBC)ViennaAustria
| | - Tim Clausen
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC)ViennaAustria
- Medical University of ViennaViennaAustria
| | - Yasin Dagdas
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna BioCenter (VBC)ViennaAustria
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19
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Evans AS, Lennemann NJ, Coyne CB. BPIFB3 Regulates Endoplasmic Reticulum Morphology To Facilitate Flavivirus Replication. J Virol 2020; 94:e00029-20. [PMID: 32102874 PMCID: PMC7163128 DOI: 10.1128/jvi.00029-20] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Accepted: 02/14/2020] [Indexed: 12/20/2022] Open
Abstract
Flaviviruses, including dengue virus (DENV) and Zika virus (ZIKV), rely heavily on the availability of endoplasmic reticulum (ER) membranes throughout their life cycle, and degradation of ER membranes restricts flavivirus replication. Accordingly, DENV and ZIKV restrict ER turnover by protease-mediated cleavage of reticulophagy regulator 1 (RETREG1), also known as FAM134B, an autophagy receptor responsible for targeted ER sheet degradation. Given that the induction of autophagy may play an important role in flavivirus replication, the antiviral role of RETREG1 suggests that specialized autophagic pathways may have differential effects on the flavivirus life cycle. We previously identified BPI fold-containing family B member 3 (BPIFB3) as a regulator of autophagy that negatively controls enterovirus replication. Here, we show that in contrast to enteroviruses, BPIFB3 functions as a positive regulator of DENV and ZIKV infection and that its RNA interference-mediated silencing inhibits the formation of viral replication organelles. Mechanistically, we show that depletion of BPIFB3 enhances RETREG1-dependent reticulophagy, leading to enhanced ER turnover and the suppression of viral replication. Consistent with this, the antiviral effects of BPIFB3 depletion can be reversed by RETREG1 silencing, suggesting a specific role for BPIFB3 in regulating ER turnover. These studies define BPIFB3 as a required host factor for both DENV and ZIKV replication and further contribute to our understanding of the requirements for autophagy during flavivirus infection.IMPORTANCE Flaviviruses and other arthropod-transmitted viruses represent a widespread global health problem, with limited treatment options currently available. Thus, a better understanding of the cellular requirements for their infection is needed. Both DENV and ZIKV rely on expansion of the endoplasmic reticulum (ER) and the induction of autophagy to establish productive infections. However, little is known regarding the interplay between the requirements for autophagy initiation during infection and the mechanisms used by these viruses to avoid clearance through the autophagic pathway. Our study highlights the importance of the host factor BPIFB3 in regulating flavivirus replication and further confirms that the RETREG1-dependent reticulophagy pathway is antiviral to both DENV and ZIKV.
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Affiliation(s)
- Azia S Evans
- Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
- Center for Microbial Pathogenesis, UPMC Children's Hospital of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Nicholas J Lennemann
- Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
- Center for Microbial Pathogenesis, UPMC Children's Hospital of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Carolyn B Coyne
- Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
- Center for Microbial Pathogenesis, UPMC Children's Hospital of Pittsburgh, Pittsburgh, Pennsylvania, USA
- Richard K. Mellon Institute for Pediatric Research, UPMC Children's Hospital of Pittsburgh, Pittsburgh, Pennsylvania, USA
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20
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ER-Phagy: Quality Control and Turnover of Endoplasmic Reticulum. Trends Cell Biol 2020; 30:384-398. [PMID: 32302550 DOI: 10.1016/j.tcb.2020.02.001] [Citation(s) in RCA: 158] [Impact Index Per Article: 39.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 01/30/2020] [Accepted: 02/03/2020] [Indexed: 12/11/2022]
Abstract
The endoplasmic reticulum (ER) is the largest organelle in cells and has fundamental functions, such as folding, processing, and trafficking of proteins, cellular metabolism, and ion storage. To maintain its function, it is turned over constitutively, and even more actively under certain stress conditions. Quality control of the ER is mediated primarily by two pathways: the ubiquitin-proteasome system and autophagy (termed 'ER-phagy'). The identification of ER-phagy adaptor molecules has shed light on the mechanisms and physiological significance of ER-phagy. Here, we describe recent findings on various types of ER-phagy and present unanswered questions related to their mechanism and regulation.
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21
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D'Eletto M, Oliverio S, Di Sano F. Reticulon Homology Domain-Containing Proteins and ER-Phagy. Front Cell Dev Biol 2020; 8:90. [PMID: 32154249 PMCID: PMC7047209 DOI: 10.3389/fcell.2020.00090] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Accepted: 02/04/2020] [Indexed: 12/17/2022] Open
Abstract
The endoplasmic reticulum (ER) is a dynamic membrane system comprising different and interconnected subdomains. The ER structure changes in response to different stress conditions through the activation of a selective autophagic pathway called ER-phagy. This represents a quality control mechanism for ER turnover and component recycling. Several ER-resident proteins have been indicated as receptors for ER-phagy; among these, there are proteins characterized by the presence of a reticulon homology domain (RHD). RHD-containing proteins promote ER fragmentation by a mechanism that involves LC3 binding and lysosome delivery. Moreover, the presence of a correct RHD structure is closely related to their capability to regulate ER shape and morphology by curvature induction and membrane remodeling. Deregulation of the ER-selective autophagic pathway due to defects in proteins with RHD has been implicated in several human diseases, infectious and neurodegenerative diseases in particular, as well as in cancer development. While the molecular mechanisms and the physiological role of ER-phagy are not yet fully understood, it is quite clear that this process is involved in different cellular signaling pathways and has an impact in several human pathologies.
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Affiliation(s)
- Manuela D'Eletto
- Department of Biology, University of Rome "Tor Vergata," Rome, Italy
| | - Serafina Oliverio
- Department of Biology, University of Rome "Tor Vergata," Rome, Italy
| | - Federica Di Sano
- Department of Biology, University of Rome "Tor Vergata," Rome, Italy
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