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Boyle E, Wilfling F. Autophagy as a caretaker of nuclear integrity. FEBS Lett 2023; 597:2728-2738. [PMID: 37567863 DOI: 10.1002/1873-3468.14719] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Revised: 07/31/2023] [Accepted: 08/02/2023] [Indexed: 08/13/2023]
Abstract
Due to their essential functions, dysregulation of nuclear pore complexes (NPCs) is strongly associated with numerous human diseases, including neurodegeneration and cancer. On a cellular level, longevity of scaffold nucleoporins in postmitotic cells of both C. elegans and mammals renders them vulnerable to age-related damage, which is associated with an increase in pore leakiness and accumulation of intranuclear aggregates in rat brain cells. Thus, understanding the mechanisms which underpin the homeostasis of this complex, as well as other nuclear proteins, is essential. In this review, autophagy-mediated degradation pathways governing nuclear components in yeast will be discussed, with a particular focus on NPCs. Furthermore, the various nuclear degradation mechanisms identified thus far in diverse eukaryotes will also be highlighted.
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Affiliation(s)
- Emily Boyle
- Mechanisms of Cellular Quality Control, Max Planck Institute of Biophysics, Frankfurt, Germany
| | - Florian Wilfling
- Mechanisms of Cellular Quality Control, Max Planck Institute of Biophysics, Frankfurt, Germany
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2
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Hao X, Sun J, Zhong L, Baudry M, Bi X. UBE3A deficiency-induced autophagy is associated with activation of AMPK-ULK1 and p53 pathways. Exp Neurol 2023; 363:114358. [PMID: 36849003 PMCID: PMC10073344 DOI: 10.1016/j.expneurol.2023.114358] [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: 12/27/2022] [Revised: 02/03/2023] [Accepted: 02/22/2023] [Indexed: 02/27/2023]
Abstract
Angelman Syndrome (AS) is a neurodevelopmental disorder caused by deficiency of the maternally expressed UBE3A gene. The UBE3A proteins functions both as an E3 ligase in the ubiquitin-proteasome system (UPS), and as a transcriptional co-activator for steroid hormone receptors. Here we investigated the effects of UBE3A deficiency on autophagy in the cerebellum of AS mice and in COS1 cells. Numbers and size of LC3- and LAMP2-immunopositive puncta were increased in cerebellar Purkinje cells of AS mice, as compared to wildtype mice. Western blot analysis showed an increase in the conversion of LC3I to LC3II in AS mice, as expected from increased autophagy. Levels of active AMPK and of one of its substrates, ULK1, a factor involved in autophagy initiation, were also increased. Colocalization of LC3 with LAMP2 was increased and p62 levels were decreased, indicating an increase in autophagy flux. UBE3A deficiency was also associated with reduced levels of phosphorylated p53 in the cytosol and increased levels in nuclei, which favors autophagy induction. UBE3A siRNA knockdown in COS-1 cells resulted in increased size and intensity of LC3-immunopositive puncta and increased the LC3 II/I ratio, as compared to control siRNA-treated cells, confirming the results found in the cerebellum of AS mice. These results indicate that UBE3A deficiency enhances autophagic activity through activation of the AMPK-ULK1 pathway and alterations in p53.
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Affiliation(s)
- Xiaoning Hao
- College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, Pomona, CA 91766, USA
| | - Jiandong Sun
- College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, Pomona, CA 91766, USA
| | - Li Zhong
- College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, Pomona, CA 91766, USA
| | - Michel Baudry
- College of Dental Medicine, Western University of Health Sciences, Pomona, CA 91766, USA
| | - Xiaoning Bi
- College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, Pomona, CA 91766, USA.
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3
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Chu S, Moujaber O, Lemay S, Stochaj U. Multiple pathways promote microtubule stabilization in senescent intestinal epithelial cells. NPJ AGING 2022; 8:16. [PMID: 36526654 PMCID: PMC9758230 DOI: 10.1038/s41514-022-00097-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/10/2020] [Accepted: 11/25/2022] [Indexed: 12/23/2022]
Abstract
Intestinal epithelial cells are critical for gastrointestinal homeostasis. However, their function declines during aging. The aging-related loss of organ performance is largely driven by the increase in senescent cells. To date, the hallmarks and molecular mechanisms related to cellular senescence are not fully understood. Microtubules control epithelial functions, and we identified microtubule stabilization as a phenotypic marker of senescent intestinal epithelial cells. The senescence inducer determined the pathway to microtubule stabilization. Specifically, enhanced microtubule stability was associated with α-tubulin hyperacetylation or increased abundance of the microtubule-binding protein tau. We show further that overexpression of MAPT, which encodes tau, augmented microtubule stability in intestinal epithelial cells. Notably, pharmacological microtubule stabilization was sufficient to induce cellular senescence. Taken together, this study provides new insights into the molecular mechanisms that control epithelial cell homeostasis. Our results support the concept that microtubule stability serves as a critical cue to trigger intestinal epithelial cell senescence.
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Affiliation(s)
- Siwei Chu
- grid.14709.3b0000 0004 1936 8649Department of Physiology, McGill University, Montreal, Quebec H3G 1Y6 Canada
| | - Ossama Moujaber
- grid.14709.3b0000 0004 1936 8649Department of Physiology, McGill University, Montreal, Quebec H3G 1Y6 Canada
| | - Serge Lemay
- grid.63984.300000 0000 9064 4811Department of Medicine, Division of Nephrology, McGill University Health Centre, Montreal, QC Canada
| | - Ursula Stochaj
- grid.14709.3b0000 0004 1936 8649Department of Physiology, McGill University, Montreal, Quebec H3G 1Y6 Canada
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4
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Shukla A, Hoffmann G, Kushwaha NK, López-González S, Hofius D, Hafrén A. Salicylic acid and the viral virulence factor 2b regulate the divergent roles of autophagy during cucumber mosaic virus infection. Autophagy 2022; 18:1450-1462. [PMID: 34740306 PMCID: PMC9225522 DOI: 10.1080/15548627.2021.1987674] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Macroautophagy/autophagy is a conserved intracellular degradation pathway that has recently emerged as an integral part of plant responses to virus infection. The known mechanisms of autophagy range from the selective degradation of viral components to a more general attenuation of disease symptoms. In addition, several viruses are able to manipulate the autophagy machinery and counteract autophagy-dependent resistance. Despite these findings, the complex interplay of autophagy activities, viral pathogenicity factors, and host defense pathways in disease development remains poorly understood. In the current study, we analyzed the interaction between autophagy and cucumber mosaic virus (CMV) in Arabidopsis thaliana. We show that autophagy is induced during CMV infection and promotes the turnover of the major virulence protein and RNA silencing suppressor 2b. Intriguingly, autophagy induction is mediated by salicylic acid (SA) and dampened by the CMV virulence factor 2b. In accordance with 2b degradation, we found that autophagy provides resistance against CMV by reducing viral RNA accumulation in an RNA silencing-dependent manner. Moreover, autophagy and RNA silencing attenuate while SA promotes CMV disease symptoms, and epistasis analysis suggests that autophagy-dependent disease and resistance are uncoupled. We propose that autophagy counteracts CMV virulence via both 2b degradation and reduced SA-responses, thereby increasing plant fitness with the viral trade-off arising from increased RNA silencing-mediated resistance.
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Affiliation(s)
- Aayushi Shukla
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, Box 7080, 75007Uppsala, Sweden
| | - Gesa Hoffmann
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, Box 7080, 75007Uppsala, Sweden
| | - Nirbhay Kumar Kushwaha
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, Box 7080, 75007Uppsala, Sweden
| | - Silvia López-González
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, Box 7080, 75007Uppsala, Sweden
| | - Daniel Hofius
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, Box 7080, 75007Uppsala, Sweden
| | - Anders Hafrén
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, Box 7080, 75007Uppsala, Sweden
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5
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Houghton OH, Mizielinska S, Gomez-Suaga P. The Interplay Between Autophagy and RNA Homeostasis: Implications for Amyotrophic Lateral Sclerosis and Frontotemporal Dementia. Front Cell Dev Biol 2022; 10:838402. [PMID: 35573690 PMCID: PMC9096704 DOI: 10.3389/fcell.2022.838402] [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: 12/17/2021] [Accepted: 04/14/2022] [Indexed: 01/18/2023] Open
Abstract
Amyotrophic lateral sclerosis and frontotemporal dementia are neurodegenerative disorders that lie on a disease spectrum, sharing genetic causes and pathology, and both without effective therapeutics. Two pathways that have been shown to play major roles in disease pathogenesis are autophagy and RNA homeostasis. Intriguingly, there is an increasing body of evidence suggesting a critical interplay between these pathways. Autophagy is a multi-stage process for bulk and selective clearance of malfunctional cellular components, with many layers of regulation. Although the majority of autophagy research focuses on protein degradation, it can also mediate RNA catabolism. ALS/FTD-associated proteins are involved in many stages of autophagy and autophagy-mediated RNA degradation, particularly converging on the clearance of persistent pathological stress granules. In this review, we will summarise the progress in understanding the autophagy-RNA homeostasis interplay and how that knowledge contributes to our understanding of the pathobiology of ALS/FTD.
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Affiliation(s)
- O H Houghton
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Maurice Wohl Clinical Neuroscience Institute, London, United Kingdom.,UK Dementia Research Institute at King's College London, London, United Kingdom
| | - S Mizielinska
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Maurice Wohl Clinical Neuroscience Institute, London, United Kingdom.,UK Dementia Research Institute at King's College London, London, United Kingdom
| | - P Gomez-Suaga
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Maurice Wohl Clinical Neuroscience Institute, London, United Kingdom.,Departamento de Bioquímica y Biología Molecular y Genética, Facultad de Enfermería y Terapia Ocupacional, Universidad de Extremadura, Cáceres, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain.,Instituto Universitario de Investigación Biosanitaria de Extremadura (INUBE), Cáceres, Spain
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6
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Kumar AV, Kang T, Thakurta TG, Ng C, Rogers AN, Larsen MR, Lapierre LR. Exportin 1 modulates life span by regulating nucleolar dynamics via the autophagy protein LGG-1/GABARAP. SCIENCE ADVANCES 2022; 8:eabj1604. [PMID: 35363528 PMCID: PMC10938577 DOI: 10.1126/sciadv.abj1604] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Accepted: 02/08/2022] [Indexed: 06/14/2023]
Abstract
Altered nucleolar and ribosomal dynamics are key hallmarks of aging, but their regulation remains unclear. Building on the knowledge that the conserved nuclear export receptor Exportin 1 (XPO-1/XPO1) modulates proteostasis and life span, we systematically analyzed the impact of nuclear export on protein metabolism. Using transcriptomic and subcellular proteomic analyses in nematodes, we demonstrate that XPO-1 modulates the nucleocytoplasmic distribution of key proteins involved in nucleolar dynamics and ribosome function, including fibrillarin (FIB-1/FBL) and RPL-11 (RPL11). Silencing xpo-1 led to marked reduction in global translation, which was accompanied by decreased nucleolar size and lower fibrillarin levels. A targeted screen of known proteostatic mediators revealed that the autophagy protein LGG-1/GABARAP modulates nucleolar size by regulating RPL-11 levels, linking specific protein degradation to ribosome metabolism. Together, our study reveals that nucleolar size and life span are regulated by LGG-1/GABARAP via ribosome protein surveillance.
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Affiliation(s)
- Anita V. Kumar
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, 185 Meeting St., Providence, RI 02912, USA
| | - Taewook Kang
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
| | - Tara G. Thakurta
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, 185 Meeting St., Providence, RI 02912, USA
| | - Celeste Ng
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, 185 Meeting St., Providence, RI 02912, USA
| | - Aric N. Rogers
- MDI Biological Laboratory, 159 Old Bar Harbor Rd., Salisbury Cove, ME 04672, USA
| | - Martin R. Larsen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
| | - Louis R. Lapierre
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, 185 Meeting St., Providence, RI 02912, USA
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7
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Liu P, Wu A, Li H, Zhang J, Ni J, Quan Z, Qing H. Rab21 Protein Is Degraded by Both the Ubiquitin-Proteasome Pathway and the Autophagy-Lysosome Pathway. Int J Mol Sci 2022; 23:ijms23031131. [PMID: 35163051 PMCID: PMC8835697 DOI: 10.3390/ijms23031131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 01/17/2022] [Accepted: 01/17/2022] [Indexed: 02/05/2023] Open
Abstract
Rab21 is a GTPase protein that is functional in intracellular trafficking and involved in the pathologies of many diseases, such as Alzheimer’s disease (AD), glioma, cancer, etc. Our previous work has reported its interaction with the catalytic subunit of gamma-secretase, PS1, and it regulates the activity of PS1 via transferring it from the early endosome to the late endosome/lysosome. However, it is still unknown how Rab21 protein itself is regulated. This work revealed that Rab21 protein, either endogenously or exogenously, can be degraded by the ubiquitin-proteasome pathway and the autophagy-lysosome pathway. It is further observed that the ubiquitinated Rab21 is increased, but the total protein is unchanged in AD model mice. We further observed that overexpression of Rab21 leads to increased expression of a series of genes involved in the autophagy-lysosome pathway. We speculated that even though the ubiquitinated Rab21 is increased due to the impaired proteasome function in the AD model, the autophagy-lysosome pathway functions in parallel to degrade Rab21 to keep its protein level in homeostasis. In conclusion, understanding the characters of Rab21 protein itself help explore its potential as a target for therapeutic strategy in diseases.
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8
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Trisciuoglio D, Degrassi F. The Tubulin Code and Tubulin-Modifying Enzymes in Autophagy and Cancer. Cancers (Basel) 2021; 14:cancers14010006. [PMID: 35008169 PMCID: PMC8750717 DOI: 10.3390/cancers14010006] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 12/15/2021] [Accepted: 12/16/2021] [Indexed: 12/17/2022] Open
Abstract
Simple Summary Microtubules are tubulin polymers that constitute the structure of eukaryotic cells. They control different cell functions that are often deregulated in cancer, such as cell shape, cell motility and the intracellular movement of organelles. Here, we focus on the crucial role of tubulin modifications in determining different cancer characteristics, including metastatic cell migration and therapy resistance. We also discuss the influence of microtubule modifications on the autophagic process—the cellular degradation pathway that influences cancer growth. We discuss findings showing that inducing microtubule modifications can be used as a means to kill cancer cells by inhibiting autophagy. Abstract Microtubules are key components of the cytoskeleton of eukaryotic cells. Microtubule dynamic instability together with the “tubulin code” generated by the choice of different α- and β- tubulin isoforms and tubulin post-translational modifications have essential roles in the control of a variety of cellular processes, such as cell shape, cell motility, and intracellular trafficking, that are deregulated in cancer. In this review, we will discuss available evidence that highlights the crucial role of the tubulin code in determining different cancer phenotypes, including metastatic cell migration, drug resistance, and tumor vascularization, and the influence of modulating tubulin-modifying enzymes on cancer cell survival and aggressiveness. We will also discuss the role of post-translationally modified microtubules in autophagy—the lysosomal-mediated cellular degradation pathway—that exerts a dual role in many cancer types, either promoting or suppressing cancer growth. We will give particular emphasis to the role of tubulin post-translational modifications and their regulating enzymes in controlling the different stages of the autophagic process in cancer cells, and consider how the experimental modulation of tubulin-modifying enzymes influences the autophagic process in cancer cells and impacts on cancer cell survival and thereby represents a new and fruitful avenue in cancer therapy.
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9
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Rayevsky A, Ozheredov DS, Samofalova D, Ozheredov SP, Karpov PA, Blume YB. The Role of Posttranslational Acetylation in the Association of Autophagy Protein ATG8 with Microtubules in Plant Cells. CYTOL GENET+ 2021. [DOI: 10.3103/s0095452721060128] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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10
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Molecular mechanisms of mammalian autophagy. Biochem J 2021; 478:3395-3421. [PMID: 34554214 DOI: 10.1042/bcj20210314] [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: 04/30/2021] [Revised: 07/19/2021] [Accepted: 07/28/2021] [Indexed: 02/06/2023]
Abstract
The ubiquitin-proteasome pathway (UPP) and autophagy play integral roles in cellular homeostasis. As part of their normal life cycle, most proteins undergo ubiquitination for some form of redistribution, localization and/or functional modulation. However, ubiquitination is also important to the UPP and several autophagic processes. The UPP is initiated after specific lysine residues of short-lived, damaged or misfolded proteins are conjugated to ubiquitin, which targets these proteins to proteasomes. Autophagy is the endosomal/lysosomal-dependent degradation of organelles, invading microbes, zymogen granules and macromolecules such as protein, carbohydrates and lipids. Autophagy can be broadly separated into three distinct subtypes termed microautophagy, chaperone-mediated autophagy and macroautophagy. Although autophagy was once thought of as non-selective bulk degradation, advancements in the field have led to the discovery of several selective forms of autophagy. Here, we focus on the mechanisms of primary and selective mammalian autophagy pathways and highlight the current knowledge gaps in these molecular pathways.
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11
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Jacomin AC, Petridi S, Di Monaco M, Bhujabal Z, Jain A, Mulakkal NC, Palara A, Powell EL, Chung B, Zampronio C, Jones A, Cameron A, Johansen T, Nezis IP. Regulation of Expression of Autophagy Genes by Atg8a-Interacting Partners Sequoia, YL-1, and Sir2 in Drosophila. Cell Rep 2021; 31:107695. [PMID: 32460019 PMCID: PMC7262597 DOI: 10.1016/j.celrep.2020.107695] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 04/07/2020] [Accepted: 05/06/2020] [Indexed: 01/09/2023] Open
Abstract
Autophagy is the degradation of cytoplasmic material through the lysosomal pathway. One of the most studied autophagy-related proteins is LC3. Despite growing evidence that LC3 is enriched in the nucleus, its nuclear role is poorly understood. Here, we show that Drosophila Atg8a protein, homologous to mammalian LC3, interacts with the transcription factor Sequoia in a LIR motif-dependent manner. We show that Sequoia depletion induces autophagy in nutrient-rich conditions through the enhanced expression of autophagy genes. We show that Atg8a interacts with YL-1, a component of a nuclear acetyltransferase complex, and that it is acetylated in nutrient-rich conditions. We also show that Atg8a interacts with the deacetylase Sir2, which deacetylates Atg8a during starvation to activate autophagy. Our results suggest a mechanism of regulation of the expression of autophagy genes by Atg8a, which is linked to its acetylation status and its interaction with Sequoia, YL-1, and Sir2. Transcription factor Sequoia is a negative regulator of autophagy Sequoia interacts with Atg8a via a LIR motif Atg8a interacts with YL-1, a subunit of a nuclear acetyltransferase complex Sir2 interacts with and deacetylates Atg8a during starvation
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Affiliation(s)
| | - Stavroula Petridi
- School of Life Sciences, University of Warwick, CV4 7AL Coventry, UK
| | - Marisa Di Monaco
- School of Life Sciences, University of Warwick, CV4 7AL Coventry, UK
| | - Zambarlal Bhujabal
- Molecular Cancer Research Group, Institute of Medical Biology, University of Tromsø-The Arctic University of Norway, 9037 Tromsø, Norway
| | - Ashish Jain
- Molecular Cancer Research Group, Institute of Medical Biology, University of Tromsø-The Arctic University of Norway, 9037 Tromsø, Norway; Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Montebello, 0379 Oslo, Norway; Centre for Cancer Cell Reprogramming, Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Montebello, 0379 Oslo, Norway
| | - Nitha C Mulakkal
- School of Life Sciences, University of Warwick, CV4 7AL Coventry, UK
| | - Anthimi Palara
- School of Life Sciences, University of Warwick, CV4 7AL Coventry, UK; Molecular Cancer Research Group, Institute of Medical Biology, University of Tromsø-The Arctic University of Norway, 9037 Tromsø, Norway
| | - Emma L Powell
- School of Life Sciences, University of Warwick, CV4 7AL Coventry, UK
| | - Bonita Chung
- School of Life Sciences, University of Warwick, CV4 7AL Coventry, UK
| | | | - Alexandra Jones
- School of Life Sciences, University of Warwick, CV4 7AL Coventry, UK
| | - Alexander Cameron
- School of Life Sciences, University of Warwick, CV4 7AL Coventry, UK
| | - Terje Johansen
- Molecular Cancer Research Group, Institute of Medical Biology, University of Tromsø-The Arctic University of Norway, 9037 Tromsø, Norway
| | - Ioannis P Nezis
- School of Life Sciences, University of Warwick, CV4 7AL Coventry, UK.
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12
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Hiraga C, Yamamoto S, Hashimoto S, Kasahara M, Minamisawa T, Matsumura S, Katakura A, Yajima Y, Nomura T, Shiba K. Pentapartite fractionation of particles in oral fluids by differential centrifugation. Sci Rep 2021; 11:3326. [PMID: 33558596 PMCID: PMC7870959 DOI: 10.1038/s41598-021-82451-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Accepted: 01/18/2021] [Indexed: 12/30/2022] Open
Abstract
Oral fluids (OFs) contain small extracellular vesicles (sEVs or exosomes) that carry disease-associated diagnostic molecules. However, cells generate extracellular vesicles (EVs) other than sEVs, so the EV population is quite heterogeneous. Furthermore, molecules not packaged in EVs can also serve as diagnostic markers. For these reasons, developing a complete picture of particulate matter in the oral cavity is important before focusing on specific subtypes of EVs. Here, we used differential centrifugation to fractionate human OFs from healthy volunteers and patients with oral squamous cell carcinoma into 5 fractions, and we characterized the particles, nucleic acids, and proteins in each fraction. Canonical exosome markers, including CD63, CD9, CD133, and HSP70, were found in all fractions, whereas CD81 and AQP5 were enriched in the 160K fraction, with non-negligible amounts in the 2K fraction. The 2K fraction also contained its characteristic markers that included short derivatives of EGFR and E-cadherin, as well as an autophagosome marker, LC3, and large multi-layered vesicles were observed by electronic microscopy. Most of the DNA and RNA was recovered from the 0.3K and 2K fractions, with some in the 160K fraction. These results can provide guideline information for development of purpose-designed OF-based diagnostic systems.
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Affiliation(s)
- Chiho Hiraga
- Division of Protein Engineering, Cancer Institute, Japanese Foundation for Cancer Research, Ariake 3-8-31, Koto-ku, Tokyo, 135-8550, Japan
- Department of Oral Oncology, Oral and Maxillofacial Surgery, Tokyo Dental College, 5-11-13 Sugano, Ichikawa, Chiba, 272-8513, Japan
| | - Satoshi Yamamoto
- Department of Pharmacology, Tokyo Dental College, 2-1-14 Misaki-cho, Chiyoda-ku, Tokyo, 101-0061, Japan
| | - Sadamitsu Hashimoto
- Laboratory of Biology, Tokyo Dental College, 2-9-7 Kanda-Surugadai, Chiyoda-ku, Tokyo, 101-0062, Japan
| | - Masataka Kasahara
- Department of Pharmacology, Tokyo Dental College, 2-1-14 Misaki-cho, Chiyoda-ku, Tokyo, 101-0061, Japan
| | - Tamiko Minamisawa
- Division of Protein Engineering, Cancer Institute, Japanese Foundation for Cancer Research, Ariake 3-8-31, Koto-ku, Tokyo, 135-8550, Japan
| | - Sachiko Matsumura
- Division of Protein Engineering, Cancer Institute, Japanese Foundation for Cancer Research, Ariake 3-8-31, Koto-ku, Tokyo, 135-8550, Japan
| | - Akira Katakura
- Department of Oral Pathobiological Science and Surgery, Tokyo Dental College, 2-9-18 Misaki-cho, Chiyoda-ku, Tokyo, 101-0061, Japan
| | - Yasutomo Yajima
- Department of Oral Implantology, Tokyo Dental College, 2-9-18 Misaki-cho, Chiyoda-ku, Tokyo, 101-0061, Japan
| | - Takeshi Nomura
- Department of Oral Oncology, Oral and Maxillofacial Surgery, Tokyo Dental College, 5-11-13 Sugano, Ichikawa, Chiba, 272-8513, Japan
| | - Kiyotaka Shiba
- Division of Protein Engineering, Cancer Institute, Japanese Foundation for Cancer Research, Ariake 3-8-31, Koto-ku, Tokyo, 135-8550, Japan.
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13
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Limited Proteolysis-Coupled Mass Spectrometry Identifies Phosphatidylinositol 4,5-Bisphosphate Effectors in Human Nuclear Proteome. Cells 2021; 10:cells10010068. [PMID: 33406800 PMCID: PMC7824793 DOI: 10.3390/cells10010068] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 12/23/2020] [Accepted: 12/29/2020] [Indexed: 12/20/2022] Open
Abstract
Specific nuclear sub-compartments that are regions of fundamental processes such as gene expression or DNA repair, contain phosphoinositides (PIPs). PIPs thus potentially represent signals for the localization of specific proteins into different nuclear functional domains. We performed limited proteolysis followed by label-free quantitative mass spectrometry and identified nuclear protein effectors of the most abundant PIP—phosphatidylinositol 4,5-bisphosphate (PIP2). We identified 515 proteins with PIP2-binding capacity of which 191 ‘exposed’ proteins represent a direct PIP2 interactors and 324 ‘hidden’ proteins, where PIP2 binding was increased upon trypsin treatment. Gene ontology analysis revealed that ‘exposed’ proteins are involved in the gene expression as regulators of Pol II, mRNA splicing, and cell cycle. They localize mainly to non-membrane bound organelles—nuclear speckles and nucleolus and are connected to the actin nucleoskeleton. ‘Hidden’ proteins are linked to the gene expression, RNA splicing and transport, cell cycle regulation, and response to heat or viral infection. These proteins localize to the nuclear envelope, nuclear pore complex, or chromatin. Bioinformatic analysis of peptides bound in both groups revealed that PIP2-binding motifs are in general hydrophilic. Our data provide an insight into the molecular mechanism of nuclear PIP2 protein interaction and advance the methodology applicable for further studies of PIPs or other protein ligands.
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14
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Odle RI, Florey O, Ktistakis NT, Cook SJ. CDK1, the Other 'Master Regulator' of Autophagy. Trends Cell Biol 2020; 31:95-107. [PMID: 33272830 DOI: 10.1016/j.tcb.2020.11.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 10/30/2020] [Accepted: 11/03/2020] [Indexed: 12/13/2022]
Abstract
Autophagy and cap-dependent mRNA translation are tightly regulated by the mechanistic target of rapamycin complex 1 (mTORC1) signalling complex in response to nutrient availability. However, the regulation of these processes, and mTORC1 itself, is different during mitosis, and this has remained an area of significant controversy; for example, studies have argued that autophagy is either repressed or highly active during mitosis. Recent studies have shown that autophagy initiation is repressed, and cap-dependent mRNA translation is maintained during mitosis despite mTORC1 activity being repressed. This is achieved in large part by a switch from mTORC1- to cyclin-dependent kinase 1 (CDK1)-mediated regulation. Here, we review the history and recent advances and seek to present a unifying model to inform the future study of autophagy and mTORC1 during mitosis.
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Affiliation(s)
- Richard I Odle
- Signalling Laboratory, The Babraham Institute, Babraham Research Campus, Cambridge, CB22 3AT, UK
| | - Oliver Florey
- Signalling Laboratory, The Babraham Institute, Babraham Research Campus, Cambridge, CB22 3AT, UK
| | - Nicholas T Ktistakis
- Signalling Laboratory, The Babraham Institute, Babraham Research Campus, Cambridge, CB22 3AT, UK
| | - Simon J Cook
- Signalling Laboratory, The Babraham Institute, Babraham Research Campus, Cambridge, CB22 3AT, UK.
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15
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Shim MS, Nettesheim A, Hirt J, Liton PB. The autophagic protein LC3 translocates to the nucleus and localizes in the nucleolus associated to NUFIP1 in response to cyclic mechanical stress. Autophagy 2020; 16:1248-1261. [PMID: 31476975 PMCID: PMC7469449 DOI: 10.1080/15548627.2019.1662584] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 08/18/2019] [Accepted: 08/28/2019] [Indexed: 12/19/2022] Open
Abstract
The trabecular meshwork (TM) is a key regulatory tissue of intraocular pressure (IOP) in the anterior chamber of eye. Dysfunction of the TM causes resistance to outflow of aqueous humor, which in turn leads to elevated IOP, a main risk factor of glaucomatous neurodegeneration. Due to variations in IOP, TM cells are continuously exposed to mechanical deformations. We previously reported activation of macroautophagy/autophagy, as one of the physiological responses elicited in TM cells following mechanical strain application. By using biochemical fractionation analysis and imaging techniques, we demonstrate here for the first time the nuclear accumulation of the autophagic marker MAP1LC3/LC3 (microtubule associated protein1 light chain 3)-II, endogenous and exogenously added (AdGFP-LC3, AdtfLC3), in response to cyclic mechanical stress (CMS). Wheat germ agglutinin (WGA) and leptomycin B treatment suggest LC3 to enter the nucleus by passive diffusion, but to exit in an XPO1/CRM1 (exportin 1)-dependent manner in human TM (hTM) cells. While blockage of nuclear export leads to accumulation of LC3 with promyelocytic leukemia (PML) bodies, nuclear LC3 localizes in the nucleolus in cells under CMS. Moreover, nuclear LC3 co-immunoprecipitated with NUFIP1, a ribosome receptor for starvation-induced ribophagy. More interestingly, we further demonstrate that NUFIP1 translocates from the nucleus to LAMP2 (lysosomal associated membrane protein 2)-positive organelles in the stretched cells without triggering ribophagy, suggesting a more general role of NUFIP1 as a selective autophagy receptor for another yet-to-be-identified target in CMS and a surveillance role of nuclear LC3 against stretch-induced damage. ABBREVIATION AdGFP: adenovirus encoding GFP; ATG: autophagy-related; BSA: bovine serum albumin; CMS: cyclic mechanical stretch; Co-IP: coimmunoprecipitation; DAPI: 4',6-diamidino-2-phenylindole; DFCs: dense fibrillar components; EM: electron microscopy; FCs: fibrillar centers; GCs: granular components; GFP: green fluorescent protein; hTM: human trabecular meshwork; HBSS: Hanks balanced salt solution; IOP: intraocular pressure; LAMP1/2: lysosomal associated membrane protein 1/2; LepB: leptomycin B; MTOR: mechanistic target of rapamacyin kinase; NES: nuclear export signals; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; NLS: nuclear localization signal; NPCs: nuclear pore complexes; NUFIP1: nuclear FMR1 interacting protein 1; NS: non-stretched; PBS: phosphate-buffered saline; PE: phosphatidylethanolamine; pfu: plaque-forming units; PML: promyelocytic leukemia; RFP: red fluorescent protein; RPS15A: ribosomal protein S15a; RPL26: ribosomal protein L26; rRNA: ribosomal RNA; SIRT1: sirtuin 1; SQSTM1/p62: sequestosome 1; tfLC3: mRFP-GFP tandem fluorescent-tagged LC3; TM: trabecular meshwork; WB: western blot; WDR36: WD repeat domain 36; WGA: wheat germ agglutinin; XPO1/CRM1: exportin 1.
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Affiliation(s)
- Myoung Sup Shim
- Department of Ophthalmology, Duke Eye Center, Duke University, Durham, NC, USA
| | - April Nettesheim
- Department of Ophthalmology, Duke Eye Center, Duke University, Durham, NC, USA
| | - Joshua Hirt
- Department of Ophthalmology, Duke Eye Center, Duke University, Durham, NC, USA
| | - Paloma B. Liton
- Department of Ophthalmology, Duke Eye Center, Duke University, Durham, NC, USA
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16
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Scherr AL, Jassowicz A, Pató A, Elssner C, Ismail L, Schmitt N, Hoffmeister P, Neukirch L, Gdynia G, Goeppert B, Schulze-Bergkamen H, Jäger D, Köhler BC. Knockdown of Atg7 Induces Nuclear-LC3 Dependent Apoptosis and Augments Chemotherapy in Colorectal Cancer Cells. Int J Mol Sci 2020; 21:E1099. [PMID: 32046105 PMCID: PMC7038172 DOI: 10.3390/ijms21031099] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Revised: 01/31/2020] [Accepted: 02/04/2020] [Indexed: 02/06/2023] Open
Abstract
Autophagy is a catabolic process that enables cells to degrade obsolete content and refuel energy depots. In colorectal cancer (CRC) autophagy has been shown to promote tumorigenesis through energy delivery in the condition of uncontrolled proliferation. With this study, we aimed at evaluating whether autophagy sustains CRC cell viability and if it impacts therapy resistance. Initially, a colorectal cancer tissue micro array, containing mucosa (n = 10), adenoma (n = 18) and adenocarcinoma (n = 49) spots, was stained for expression of essential autophagy proteins LC3b, Atg7, p62 and Beclin-1. Subsequently, central autophagy proteins were downregulated in CRC cells using siRNA technology. Viability assays, flow cytometry and immunoblotting were performed and three-dimensional cell culture was utilized to study autophagy in a tissue mimicking environment. In our study we found an upregulation of Atg7 in CRC. Furthermore, we identified Atg7 as crucial factor within the autophagy network for CRC cell viability. Its disruption induced cell death via triggering apoptosis and in combination with conventional chemotherapy it exerted synergistic effects in inducing CRC cell death. Cell death was strictly dependent on nuclear LC3b, since simultaneous knockdown of Atg7 and LC3b completely restored viability. This study unravels a novel cell death preventing function of Atg7 in interaction with LC3b, thereby unmasking a promising therapeutic target in CRC.
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Affiliation(s)
- Anna-Lena Scherr
- National Center for Tumor Diseases, University Hospital Heidelberg, Heidelberg 69120, Germany; (A.-L.S.); (A.J.); (A.P.); (C.E.); (L.I.); (N.S.); (P.H.); (D.J.)
| | - Adam Jassowicz
- National Center for Tumor Diseases, University Hospital Heidelberg, Heidelberg 69120, Germany; (A.-L.S.); (A.J.); (A.P.); (C.E.); (L.I.); (N.S.); (P.H.); (D.J.)
| | - Anna Pató
- National Center for Tumor Diseases, University Hospital Heidelberg, Heidelberg 69120, Germany; (A.-L.S.); (A.J.); (A.P.); (C.E.); (L.I.); (N.S.); (P.H.); (D.J.)
| | - Christin Elssner
- National Center for Tumor Diseases, University Hospital Heidelberg, Heidelberg 69120, Germany; (A.-L.S.); (A.J.); (A.P.); (C.E.); (L.I.); (N.S.); (P.H.); (D.J.)
| | - Lars Ismail
- National Center for Tumor Diseases, University Hospital Heidelberg, Heidelberg 69120, Germany; (A.-L.S.); (A.J.); (A.P.); (C.E.); (L.I.); (N.S.); (P.H.); (D.J.)
| | - Nathalie Schmitt
- National Center for Tumor Diseases, University Hospital Heidelberg, Heidelberg 69120, Germany; (A.-L.S.); (A.J.); (A.P.); (C.E.); (L.I.); (N.S.); (P.H.); (D.J.)
| | - Paula Hoffmeister
- National Center for Tumor Diseases, University Hospital Heidelberg, Heidelberg 69120, Germany; (A.-L.S.); (A.J.); (A.P.); (C.E.); (L.I.); (N.S.); (P.H.); (D.J.)
| | - Lasse Neukirch
- Clinical Cooperation Unit Applied Tumor Immunity, National Center for Tumor Diseases and German Cancer Research Center, Heidelberg 69120, Germany;
| | - Georg Gdynia
- Institute of Pathology, University Hospital Heidelberg, Heidelberg 69120, Germany; (G.G.); (B.G.)
| | - Benjamin Goeppert
- Institute of Pathology, University Hospital Heidelberg, Heidelberg 69120, Germany; (G.G.); (B.G.)
| | | | - Dirk Jäger
- National Center for Tumor Diseases, University Hospital Heidelberg, Heidelberg 69120, Germany; (A.-L.S.); (A.J.); (A.P.); (C.E.); (L.I.); (N.S.); (P.H.); (D.J.)
| | - Bruno Christian Köhler
- National Center for Tumor Diseases, University Hospital Heidelberg, Heidelberg 69120, Germany; (A.-L.S.); (A.J.); (A.P.); (C.E.); (L.I.); (N.S.); (P.H.); (D.J.)
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17
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Pfister AS. Emerging Role of the Nucleolar Stress Response in Autophagy. Front Cell Neurosci 2019; 13:156. [PMID: 31114481 PMCID: PMC6503120 DOI: 10.3389/fncel.2019.00156] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Accepted: 04/08/2019] [Indexed: 12/12/2022] Open
Abstract
Autophagy represents a conserved self-digestion program, which allows regulated degradation of cellular material. Autophagy is activated by cellular stress, serum starvation and nutrient deprivation. Several autophagic pathways have been uncovered, which either non-selectively or selectively target the cellular cargo for lysosomal degradation. Autophagy engages the coordinated action of various key regulators involved in the steps of autophagosome formation, cargo targeting and lysosomal fusion. While non-selective (macro)autophagy is required for removal of bulk material or recycling of nutrients, selective autophagy mediates specific targeting of damaged organelles or protein aggregates. By proper action of the autophagic machinery, cellular homeostasis is maintained. In contrast, failure of this fundamental process is accompanied by severe pathophysiological conditions. Hallmarks of neuropathological disorders are for instance accumulated, mis-folded protein aggregates and damaged mitochondria. The nucleolus has been recognized as central hub in the cellular stress response. It represents a sub-nuclear organelle essential for ribosome biogenesis and also functions as stress sensor by mediating cell cycle arrest or apoptosis. Thus, proper nucleolar function is mandatory for cell growth and survival. Here, I highlight the emerging role of nucleolar factors in the regulation of autophagy. Moreover, I discuss the nucleolar stress response as a novel signaling pathway in the context of autophagy, health and disease.
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Affiliation(s)
- Astrid S Pfister
- Institute of Biochemistry and Molecular Biology, Faculty of Medicine, Ulm University, Ulm, Germany
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18
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Li Y, Jiang X, Zhang Y, Gao Z, Liu Y, Hu J, Hu X, Li L, Shi J, Gao N. Nuclear accumulation of UBC9 contributes to SUMOylation of lamin A/C and nucleophagy in response to DNA damage. JOURNAL OF EXPERIMENTAL & CLINICAL CANCER RESEARCH : CR 2019; 38:67. [PMID: 30744690 PMCID: PMC6371487 DOI: 10.1186/s13046-019-1048-8] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Accepted: 01/17/2019] [Indexed: 12/28/2022]
Abstract
BACKGROUND Macroautophagy (hereafter referred to as autophagy) is an evolutionarily conserved intracellular mechanism for lysosomal degradation of damaged cellular components. The specific degradation of nuclear components by the autophagy pathway is called nucleophagy. Most studies have focused on autophagic turnover of cytoplasmic materials, and little is known about the role of autophagy in the degradation of nuclear components. METHODS Human MDA-MB-231 and MCF-7 breast cancer cell lines were used as model systems in vitro. Induction of nucleophagy by nuclear DNA leakage was determined by western blot and immunofluorescence analyses. The interaction and colocalization of LC3 and lamin A/C was determined by immunoprecipitation and immunofluorescence. The role of the SUMO E2 ligase, UBC9, on the regulation of SUMOylation of lamin A/C and nucleophagy was determined by siRNA silencing of UBC9, and analyzed by immunoprecipitation and immunofluorescence. RESULTS DNA damage induced nuclear accumulation of UBC9 ligase which resulted in SUMOylation of lamin A/C and that SUMOylation of this protein was required for the interaction between the autophagy protein LC3 and lamin A/C, which was required for nucleophagy. Knockdown of UBC9 prevented SUMOylation of lamin A/C and LC3-lamin A/C interaction. This attenuated nucleophagy which degraded nuclear components lamin A/C and leaked nuclear DNA mediated by DNA damage. CONCLUSIONS Our findings suggest that nuclear DNA leakage activates nucleophagy through UBC9-mediated SUMOylation of lamin A/C, leading to degradation of nuclear components including lamin A/C and leaked nuclear DNA.
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Affiliation(s)
- Yunong Li
- College of Pharmacy, Army Medical University, Chongqing, 400038, China
| | - Xiuxing Jiang
- College of Pharmacy, Army Medical University, Chongqing, 400038, China
| | - Yanhao Zhang
- College of Pharmacy, Army Medical University, Chongqing, 400038, China
| | - Ziyi Gao
- Greater Philadelphia Pharmacy, Philadelphia, USA
| | - Yanxia Liu
- College of Pharmacy, Army Medical University, Chongqing, 400038, China
| | - Jinjiao Hu
- College of Pharmacy, Army Medical University, Chongqing, 400038, China
| | - Xiaoye Hu
- College of Pharmacy, Army Medical University, Chongqing, 400038, China
| | - Lirong Li
- College of Pharmacy, Army Medical University, Chongqing, 400038, China
| | - Jingshan Shi
- Key Laboratory of Basic Pharmacology of Ministry of Education and Joint International Research Laboratory of Ethnomedicine of Ministry of Education, Zunyi Medical University, Zunyi, China.
| | - Ning Gao
- College of Pharmacy, Army Medical University, Chongqing, 400038, China. .,Key Laboratory of Basic Pharmacology of Ministry of Education and Joint International Research Laboratory of Ethnomedicine of Ministry of Education, Zunyi Medical University, Zunyi, China.
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19
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Lin KC, Lin MW, Hsu MN, Yu-Chen G, Chao YC, Tuan HY, Chiang CS, Hu YC. Graphene oxide sensitizes cancer cells to chemotherapeutics by inducing early autophagy events, promoting nuclear trafficking and necrosis. Am J Cancer Res 2018; 8:2477-2487. [PMID: 29721093 PMCID: PMC5928903 DOI: 10.7150/thno.24173] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Accepted: 02/20/2018] [Indexed: 01/08/2023] Open
Abstract
Rationale: Cisplatin (CDDP) is a broad-spectrum anticancer drug but chemoresistance to CDDP impedes its wide use for cancer therapy. Autophagy is an event occurring in the cytoplasm and cytoplasmic LC3 puncta formation is a hallmark of autophagy. Graphene oxide (GO) is a nanomaterial that provokes autophagy in CT26 colon cancer cells and confers antitumor effects. Here we aimed to evaluate whether combined use of GO with CDDP (GO/CDDP) overcomes chemoresistance in different cancer cells and uncover the underlying mechanism. Methods: We treated different cancer cells with GO/CDDP and evaluated the cytotoxicity, death mechanism, autophagy induction and nuclear entry of CDDP. We further knocked down genes essential for autophagic flux and deciphered which step is critical to nuclear import and cell death. Finally, we performed immunoprecipitation, mass spectrometry and immunofluorescence labeling to evaluate the association of LC3 and CDDP. Results: We uncovered that combination of GO and CDDP (GO/CDDP) promoted the killing of not only CT26 cells, but also ovarian, cervical and prostate cancer cells. In the highly chemosensitized Skov-3 cells, GO/CDDP significantly enhanced concurrent nuclear import of CDDP and autophagy marker LC3 and elevated cell necrosis, which required autophagy initiation and progression but did not necessitate late autophagy events (e.g., autophagosome completion and autolysosome formation). The GO/CDDP-elicited nuclear trafficking and cell death also required importin α/β, and LC3 also co-migrated with CDDP and histone H1/H4 into the nucleus. In particular, GO/CDDP triggered histone H4 acetylation in the nucleus, which could decondense the chromosome and enable CDDP to more effectively access chromosomal DNA to trigger cell death. Conclusion: These findings shed light on the mechanisms of GO/CDDP-induced chemosensitization and implicate the potential applications of GO/CDDP to treat multiple cancers.
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20
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Zhou M, Ji H, Fu N, Chen L, Xia Y. Nucleophagy in Human Disease: Beyond the Physiological Role [Retraction]. TOHOKU J EXP MED 2018; 244:75-81. [DOI: 10.1620/tjem.244.75] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Affiliation(s)
- Ming Zhou
- Department of Hematology, Hunan Provincial People’s Hospital, The First Affiliated Hospital of Hunan Normal University
| | - Hongwen Ji
- Department of Anesthesiology, Transfusion Medicine, Fuwai Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College
| | - Nian Fu
- Department of Gastroenterology, Affiliated Nanhua Hospital, University of South China
| | - Linxi Chen
- Institute of Pharmacy and Pharmacology, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China
| | - Yong Xia
- Affiliated Hospital of Xiangnan University
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21
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Parker AL, Teo WS, McCarroll JA, Kavallaris M. An Emerging Role for Tubulin Isotypes in Modulating Cancer Biology and Chemotherapy Resistance. Int J Mol Sci 2017; 18:ijms18071434. [PMID: 28677634 PMCID: PMC5535925 DOI: 10.3390/ijms18071434] [Citation(s) in RCA: 92] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Revised: 06/24/2017] [Accepted: 06/27/2017] [Indexed: 12/19/2022] Open
Abstract
Tubulin proteins, as components of the microtubule cytoskeleton perform critical cellular functions throughout all phases of the cell cycle. Altered tubulin isotype composition of microtubules is emerging as a feature of aggressive and treatment refractory cancers. Emerging evidence highlighting a role for tubulin isotypes in differentially influencing microtubule behaviour and broader functional networks within cells is illuminating a complex role for tubulin isotypes regulating cancer biology and chemotherapy resistance. This review focuses on the role of different tubulin isotypes in microtubule dynamics as well as in oncogenic changes that provide a survival or proliferative advantage to cancer cells within the tumour microenvironment and during metastatic processes. Consideration of the role of tubulin isotypes beyond their structural function will be essential to improving the current clinical use of tubulin-targeted chemotherapy agents and informing the development of more effective cancer therapies.
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Affiliation(s)
- Amelia L Parker
- Tumour Biology and Targeting, Children's Cancer Institute, Lowy Cancer Research Centre, University of New South Wales, Sydney, NSW 2031, Australia.
- Australian Centre for NanoMedicine, ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, University of New South Wales, Sydney, NSW 2052, Australia.
| | - Wee Siang Teo
- Tumour Biology and Targeting, Children's Cancer Institute, Lowy Cancer Research Centre, University of New South Wales, Sydney, NSW 2031, Australia.
- Australian Centre for NanoMedicine, ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, University of New South Wales, Sydney, NSW 2052, Australia.
| | - Joshua A McCarroll
- Tumour Biology and Targeting, Children's Cancer Institute, Lowy Cancer Research Centre, University of New South Wales, Sydney, NSW 2031, Australia.
- Australian Centre for NanoMedicine, ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, University of New South Wales, Sydney, NSW 2052, Australia.
| | - Maria Kavallaris
- Tumour Biology and Targeting, Children's Cancer Institute, Lowy Cancer Research Centre, University of New South Wales, Sydney, NSW 2031, Australia.
- Australian Centre for NanoMedicine, ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, University of New South Wales, Sydney, NSW 2052, Australia.
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22
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Salmina K, Huna A, Inashkina I, Belyayev A, Krigerts J, Pastova L, Vazquez-Martin A, Erenpreisa J. Nucleolar aggresomes mediate release of pericentric heterochromatin and nuclear destruction of genotoxically treated cancer cells. Nucleus 2017; 8:205-221. [PMID: 28068183 DOI: 10.1080/19491034.2017.1279775] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
The role of the nucleolus and autophagy in maintenance of nuclear integrity is poorly understood. In addition, the mechanisms of nuclear destruction in cancer cells senesced after conventional chemotherapy are unclear. In an attempt to elucidate these issues, we studied teratocarcinoma PA1 cells treated with Etoposide (ETO), focusing on the nucleolus. Following treatment, most cells enter G2 arrest, display persistent DNA damage and activate p53, senescence, and macroautophagy markers. 2-5 µm sized nucleolar aggresomes (NoA) containing fibrillarin (FIB) and damaged rDNA, colocalized with ubiquitin, pAMPK, and LC3-II emerge, accompanied by heterochromatin fragments, when translocated perinuclearly. Microscopic counts following application of specific inhibitors revealed that formation of FIB-NoA is dependent on deficiency of the ubiquitin proteasome system coupled to functional autophagy. In contrast, the accompanying NoAs release of pericentric heterochromatin, which exceeds their frequency, is favored by debilitation of autophagic flux. Potential survivors release NoA in the cytoplasm during rare mitoses, while exit of pericentric fragments often depleted of H3K9Me3, with or without encompassing by NoA, occurs through the nucleolar protrusions and defects of the nuclear envelope. Foci of LC3-II are accumulated in the nucleoli undergoing cessation of rDNA transcription. As an origin of heterochromatin fragmentation, the unscheduled DNA synthesis and circular DNAs were found in the perinucleolar heterochromatin shell, along with activation and retrotransposition of ALU elements, colocalized with 45S rDNA in NoAs. The data indicate coordination of the basic nucleolar function with autophagy regulation in maintenance of the integrity of the nucleolus associated domains secured by inactivity of retrotransposons.
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Affiliation(s)
| | - Anda Huna
- a Latvian Biomedical Research & Study Centre , Riga , Latvia
| | - Inna Inashkina
- a Latvian Biomedical Research & Study Centre , Riga , Latvia
| | - Alexander Belyayev
- b Botanical Institute AS CR , Czech Academy of Science , Prague, Czech Republic
| | - Jekabs Krigerts
- a Latvian Biomedical Research & Study Centre , Riga , Latvia
| | - Ladislava Pastova
- b Botanical Institute AS CR , Czech Academy of Science , Prague, Czech Republic
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23
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Abstract
Macroautophagy/autophagy is a key catabolic process, essential for maintaining cellular homeostasis and survival through the removal and recycling of unwanted cellular material. Emerging evidence has revealed intricate connections between the RNA and autophagy research fields. While a majority of studies have focused on protein, lipid and carbohydrate catabolism via autophagy, accumulating data supports the view that several types of RNA and associated ribonucleoprotein complexes are specifically recruited to phagophores (precursors to autophagosomes) and subsequently degraded in the lysosome/vacuole. Moreover, recent studies have revealed a substantial number of novel autophagy regulators with RNA-related functions, indicating roles for RNA and associated proteins not only as cargo, but also as regulators of this process. In this review, we discuss widespread evidence of RNA catabolism via autophagy in yeast, plants and animals, reviewing the molecular mechanisms and biological importance in normal physiology, stress and disease. In addition, we explore emerging evidence of core autophagy regulation mediated by RNA-binding proteins and noncoding RNAs, and point to gaps in our current knowledge of the connection between RNA and autophagy. Finally, we discuss the pathological implications of RNA-protein aggregation, primarily in the context of neurodegenerative disease.
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Affiliation(s)
- Lisa B Frankel
- a Biotech Research and Innovation Centre , University of Copenhagen , Copenhagen , Denmark
| | - Michal Lubas
- a Biotech Research and Innovation Centre , University of Copenhagen , Copenhagen , Denmark
| | - Anders H Lund
- a Biotech Research and Innovation Centre , University of Copenhagen , Copenhagen , Denmark
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24
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Kraft LJ, Dowler J, Manral P, Kenworthy AK. Size, organization, and dynamics of soluble SQSTM1 and LC3-SQSTM1 complexes in living cells. Autophagy 2016; 12:1660-74. [PMID: 27442348 DOI: 10.1080/15548627.2016.1199299] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
Selective macroautophagy/autophagy-with the help of molecular receptors-captures cargo for lysosomal degradation. Among the best-studied molecular receptors is SQSTM1/p62, a homo-oligomeric ubiquitin binding protein, which binds to both cargo and MAP1LC3B/LC3, a protein important for autophagosome biogenesis. Although the mechanisms underlying interaction of LC3 and SQSTM1 have been extensively studied, very little is known about the size or organization of soluble complexes formed between SQSTM1 and LC3 prior to phagophore (the autophagosome precursor) binding in live cells at the molecular level. To address this question, in the current study we use a combination of 2 microscopy-based approaches, FRET microscopy and confocal FRAP, to study the nanoscale properties of soluble SQSTM1 complexes and SQSTM1-LC3 complexes in living HeLa cells. We find that, independent of puncta, SQSTM1 oligomerizes to form very slowly diffusing complexes that contain multiple copies of SQSTM1 within FRET proximity of one another. Furthermore, we show that the interactions of soluble pools of LC3 and SQSTM1 can be readily detected by both FRAP and FRET. Finally, we uncover unexpected roles of SQSTM1's PB1 domain, a region of the protein involved in homo-oligomer formation, in complex formation. Taken together, these findings provide new insights into the nature of nanometer-sized protein complexes in the autophagy pathway.
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Affiliation(s)
- Lewis J Kraft
- a Chemical and Physical Biology Program , Vanderbilt University Medical Center , Nashville , TN , USA
| | - Jacob Dowler
- b Department of Molecular Physiology and Biophysics , Vanderbilt University Medical Center , Nashville , TN , USA
| | - Pallavi Manral
- b Department of Molecular Physiology and Biophysics , Vanderbilt University Medical Center , Nashville , TN , USA
| | - Anne K Kenworthy
- a Chemical and Physical Biology Program , Vanderbilt University Medical Center , Nashville , TN , USA.,b Department of Molecular Physiology and Biophysics , Vanderbilt University Medical Center , Nashville , TN , USA.,c Department of Cell and Developmental Biology , Vanderbilt University Medical Center , Nashville , TN , USA
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