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Zhang J, Tang T, Zhang R, Wen L, Deng X, Xu X, Yang W, Jin F, Cao Y, Lu Y, Yu XQ. Maintaining Toll signaling in Drosophila brain is required to sustain autophagy for dopamine neuron survival. iScience 2024; 27:108795. [PMID: 38292423 PMCID: PMC10825691 DOI: 10.1016/j.isci.2024.108795] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2023] [Revised: 10/19/2023] [Accepted: 01/02/2024] [Indexed: 02/01/2024] Open
Abstract
Macroautophagy/autophagy is a conserved process in eukaryotic cells to degrade and recycle damaged intracellular components. Higher level of autophagy in the brain has been observed, and autophagy dysfunction has an impact on neuronal health, but the molecular mechanism is unclear. In this study, we showed that overexpression of Toll-1 and Toll-7 receptors, as well as active Spätzle proteins in Drosophila S2 cells enhanced autophagy, and Toll-1/Toll-7 activated autophagy was dependent on Tube-Pelle-PP2A. Interestingly, Toll-1 but not Toll-7 mediated autophagy was dMyd88 dependent. Importantly, we observed that loss of functions in Toll-1 and Toll-7 receptors and PP2A activity in flies decreased autophagy level, resulting in the loss of dopamine (DA) neurons and reduced fly motion. Our results indicated that proper activation of Toll-1 and Toll-7 pathways and PP2A activity in the brain are necessary to sustain autophagy level for DA neuron survival.
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Affiliation(s)
- Jie Zhang
- Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, Guangzhou Key Laboratory of Insect Development Regulation and Application Research, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou 510631, China
- Key Laboratory of Bio-Pesticide Innovation and Application of Guangdong Province, College of Plant Protection, South China Agricultural University, Guangzhou 510642, Guangdong, China
| | - Ting Tang
- Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, Guangzhou Key Laboratory of Insect Development Regulation and Application Research, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou 510631, China
| | - Ruonan Zhang
- Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, Guangzhou Key Laboratory of Insect Development Regulation and Application Research, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou 510631, China
- Key Laboratory of Bio-Pesticide Innovation and Application of Guangdong Province, College of Plant Protection, South China Agricultural University, Guangzhou 510642, Guangdong, China
| | - Liang Wen
- Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, Guangzhou Key Laboratory of Insect Development Regulation and Application Research, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou 510631, China
| | - Xiaojuan Deng
- Guangdong Laboratory for Lingnan Modern Agriculture, Laboratory of Insect Molecular Biology and Biotechnology, Guangdong Provincial Key Laboratory of Agro-animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou 510642, China
| | - Xiaoxia Xu
- Key Laboratory of Bio-Pesticide Innovation and Application of Guangdong Province, College of Plant Protection, South China Agricultural University, Guangzhou 510642, Guangdong, China
| | - Wanying Yang
- Guangdong Laboratory for Lingnan Modern Agriculture, Laboratory of Insect Molecular Biology and Biotechnology, Guangdong Provincial Key Laboratory of Agro-animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou 510642, China
| | - Fengliang Jin
- Key Laboratory of Bio-Pesticide Innovation and Application of Guangdong Province, College of Plant Protection, South China Agricultural University, Guangzhou 510642, Guangdong, China
| | - Yang Cao
- Guangdong Laboratory for Lingnan Modern Agriculture, Laboratory of Insect Molecular Biology and Biotechnology, Guangdong Provincial Key Laboratory of Agro-animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou 510642, China
| | - Yuzhen Lu
- Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, Guangzhou Key Laboratory of Insect Development Regulation and Application Research, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou 510631, China
| | - Xiao-Qiang Yu
- Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, Guangzhou Key Laboratory of Insect Development Regulation and Application Research, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou 510631, China
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2
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Elander PH, Holla S, Sabljić I, Gutierrez-Beltran E, Willems P, Bozhkov PV, Minina EA. Interactome of Arabidopsis ATG5 Suggests Functions beyond Autophagy. Int J Mol Sci 2023; 24:12300. [PMID: 37569688 PMCID: PMC10418956 DOI: 10.3390/ijms241512300] [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: 07/05/2023] [Revised: 07/27/2023] [Accepted: 07/28/2023] [Indexed: 08/13/2023] Open
Abstract
Autophagy is a catabolic pathway capable of degrading cellular components ranging from individual molecules to organelles. Autophagy helps cells cope with stress by removing superfluous or hazardous material. In a previous work, we demonstrated that transcriptional upregulation of two autophagy-related genes, ATG5 and ATG7, in Arabidopsis thaliana positively affected agronomically important traits: biomass, seed yield, tolerance to pathogens and oxidative stress. Although the occurrence of these traits correlated with enhanced autophagic activity, it is possible that autophagy-independent roles of ATG5 and ATG7 also contributed to the phenotypes. In this study, we employed affinity purification and LC-MS/MS to identify the interactome of wild-type ATG5 and its autophagy-inactive substitution mutant, ATG5K128R Here we present the first interactome of plant ATG5, encompassing not only known autophagy regulators but also stress-response factors, components of the ubiquitin-proteasome system, proteins involved in endomembrane trafficking, and potential partners of the nuclear fraction of ATG5. Furthermore, we discovered post-translational modifications, such as phosphorylation and acetylation present on ATG5 complex components that are likely to play regulatory functions. These results strongly indicate that plant ATG5 complex proteins have roles beyond autophagy itself, opening avenues for further investigations on the complex roles of autophagy in plant growth and stress responses.
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Affiliation(s)
- Pernilla H. Elander
- Department of Molecular Sciences, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, 750-07 Uppsala, Sweden; (P.H.E.); (S.H.); (I.S.); (P.V.B.)
| | - Sanjana Holla
- Department of Molecular Sciences, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, 750-07 Uppsala, Sweden; (P.H.E.); (S.H.); (I.S.); (P.V.B.)
| | - Igor Sabljić
- Department of Molecular Sciences, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, 750-07 Uppsala, Sweden; (P.H.E.); (S.H.); (I.S.); (P.V.B.)
| | - Emilio Gutierrez-Beltran
- Instituto de Bioquımica Vegetal y Fotosıntesis, Universidad de Sevilla and Consejo Superior de Investigaciones Cientıficas, 41092 Sevilla, Spain;
- Departamento de Bioquimica Vegetal y Biologia Molecular, Facultad de Biologia, Universidad de Sevilla, 41012 Sevilla, Spain
| | - Patrick Willems
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium;
- Department of Biomolecular Medicine, Ghent University, 9000 Ghent, Belgium
| | - Peter V. Bozhkov
- Department of Molecular Sciences, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, 750-07 Uppsala, Sweden; (P.H.E.); (S.H.); (I.S.); (P.V.B.)
| | - Elena A. Minina
- Department of Molecular Sciences, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, 750-07 Uppsala, Sweden; (P.H.E.); (S.H.); (I.S.); (P.V.B.)
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3
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Gu S, Jiang M, Zhang B. Microcystin-LR in Primary Liver Cancers: An Overview. Toxins (Basel) 2022; 14:toxins14100715. [PMID: 36287983 PMCID: PMC9611980 DOI: 10.3390/toxins14100715] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 09/29/2022] [Accepted: 10/17/2022] [Indexed: 12/01/2022] Open
Abstract
The cyanobacterial blooms produced by eutrophic water bodies have become a serious environmental issue around the world. After cellular lysing or algaecide treatment, microcystins (MCs), which are regarded as the most frequently encountered cyanobacterial toxins in fresh water, are released into water. Among all the variants of MCs, MC-LR has been widely studied due to its severe hepatotoxicity. Since 1992, various studies have identified the important roles of MC-LR in the origin and progression of primary liver cancers (PLCs), although few reviews have focused on it. Therefore, this review aims to summarize the major achievements and shortcomings observed in the past few years. Based on the available literature, the mechanisms of how MC-LR induces or promotes PLCs are elucidated in this review. This review aims to enhance our understanding of the role that MC-LR plays in PLCs and provides a rational approach for future applications.
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Affiliation(s)
- Shen Gu
- Key Laboratory of Clinical Cancer Pharmacology and Toxicology Research of Zhejiang Province, Affiliated Hangzhou First People’s Hospital, Zhejiang University School of Medicine, Hangzhou 310006, China
- Translational Medicine Research Center, Affiliated Hangzhou First People’s Hospital, Zhejiang University School of Medicine, Hangzhou 310006, China
- Correspondence: ; Tel.: +86-0571-56007664
| | - Mingxuemei Jiang
- Institute of Scientific and Technical Information of Zhejiang Province, Hangzhou 310001, China
| | - Bo Zhang
- Key Laboratory of Clinical Cancer Pharmacology and Toxicology Research of Zhejiang Province, Affiliated Hangzhou First People’s Hospital, Zhejiang University School of Medicine, Hangzhou 310006, China
- Translational Medicine Research Center, Affiliated Hangzhou First People’s Hospital, Zhejiang University School of Medicine, Hangzhou 310006, China
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4
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Neal SJ, Zhou Q, Pignoni F. Protein Phosphatase 2A with B' specificity subunits regulates the Hippo-Yorkie signaling axis in the Drosophila eye disc. J Cell Sci 2022; 135:jcs259558. [PMID: 36205125 PMCID: PMC10614058 DOI: 10.1242/jcs.259558] [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: 12/06/2021] [Accepted: 09/22/2022] [Indexed: 11/20/2022] Open
Abstract
Hippo-Yorkie (Hpo-Yki) signaling is central to diverse developmental processes. Although its redeployment has been amply demonstrated, its context-specific regulation remains poorly understood. The Drosophila eye disc is a continuous epithelium folded into two layers, the peripodial epithelium (PE) and the retinal progenitor epithelium. Here, Yki acts in the PE, first to promote PE identity by suppressing retina fate, and subsequently to maintain proper disc morphology. In the latter process, loss of Yki results in the displacement of a portion of the differentiating retinal epithelium onto the PE side. We show that Protein Phosphatase 2A (PP2A) complexes comprising different substrate-specificity B-type subunits govern the Hpo-Yki axis in this context. These include holoenzymes containing the B‴ subunit Cka and those containing the B' subunits Wdb or Wrd. Whereas PP2A(Cka), as part of the STRIPAK complex, is known to regulate Hpo directly, PP2A(Wdb) acts genetically upstream of the antagonistic activities of the Hpo regulators Sav and Rassf. These in vivo data provide the first evidence of PP2A(B') heterotrimer function in Hpo pathway regulation and reveal pathway diversification at distinct developmental times in the same tissue.
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Affiliation(s)
- Scott J. Neal
- Department of Neuroscience & Physiology, Upstate Medical University, 505 Irving Avenue, NRB 4610, Syracuse, NY 13210, USA
| | - Qingxiang Zhou
- Department of Ophthalmology and Visual Sciences, Upstate Medical University, 505 Irving Avenue, NRB 4610, Syracuse, NY 13210, USA
| | - Francesca Pignoni
- Department of Neuroscience & Physiology, Upstate Medical University, 505 Irving Avenue, NRB 4610, Syracuse, NY 13210, USA
- Department of Ophthalmology and Visual Sciences, Upstate Medical University, 505 Irving Avenue, NRB 4610, Syracuse, NY 13210, USA
- Department of Biochemistry and Molecular Biology, Department of Cell and Developmental Biology, Upstate Medical University, 505 Irving Avenue, NRB 4610, Syracuse, NY 13210, USA
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5
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Ogienko AA, Omelina ES, Bylino OV, Batin MA, Georgiev PG, Pindyurin AV. Drosophila as a Model Organism to Study Basic Mechanisms of Longevity. Int J Mol Sci 2022; 23:ijms231911244. [PMID: 36232546 PMCID: PMC9569508 DOI: 10.3390/ijms231911244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Revised: 09/20/2022] [Accepted: 09/20/2022] [Indexed: 11/16/2022] Open
Abstract
The spatio-temporal regulation of gene expression determines the fate and function of various cells and tissues and, as a consequence, the correct development and functioning of complex organisms. Certain mechanisms of gene activity regulation provide adequate cell responses to changes in environmental factors. Aside from gene expression disorders that lead to various pathologies, alterations of expression of particular genes were shown to significantly decrease or increase the lifespan in a wide range of organisms from yeast to human. Drosophila fruit fly is an ideal model system to explore mechanisms of longevity and aging due to low cost, easy handling and maintenance, large number of progeny per adult, short life cycle and lifespan, relatively low number of paralogous genes, high evolutionary conservation of epigenetic mechanisms and signalling pathways, and availability of a wide range of tools to modulate gene expression in vivo. Here, we focus on the organization of the evolutionarily conserved signaling pathways whose components significantly influence the aging process and on the interconnections of these pathways with gene expression regulation.
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Affiliation(s)
- Anna A. Ogienko
- Department of Regulation of Genetic Processes, Institute of Molecular and Cellular Biology SB RAS, 630090 Novosibirsk, Russia
| | - Evgeniya S. Omelina
- Department of Regulation of Genetic Processes, Institute of Molecular and Cellular Biology SB RAS, 630090 Novosibirsk, Russia
- Laboratory of Biotechnology, Novosibirsk State Agrarian University, 630039 Novosibirsk, Russia
| | - Oleg V. Bylino
- Laboratory of Gene Expression Regulation in Development, Institute of Gene Biology RAS, 119334 Moscow, Russia
| | - Mikhail A. Batin
- Open Longevity, 15260 Ventura Blvd., Sherman Oaks, Los Angeles, CA 91403, USA
| | - Pavel G. Georgiev
- Laboratory of Gene Expression Regulation in Development, Institute of Gene Biology RAS, 119334 Moscow, Russia
| | - Alexey V. Pindyurin
- Department of Regulation of Genetic Processes, Institute of Molecular and Cellular Biology SB RAS, 630090 Novosibirsk, Russia
- Correspondence: ; Tel.: +7-383-363-90-42
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Schreiber A, Collins BC, Davis C, Enchev RI, Sedra A, D'Antuono R, Aebersold R, Peter M. Multilayered regulation of autophagy by the Atg1 kinase orchestrates spatial and temporal control of autophagosome formation. Mol Cell 2021; 81:5066-5081.e10. [PMID: 34798055 PMCID: PMC8693860 DOI: 10.1016/j.molcel.2021.10.024] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 07/23/2021] [Accepted: 10/26/2021] [Indexed: 12/26/2022]
Abstract
Autophagy is a conserved intracellular degradation pathway exerting various cytoprotective and homeostatic functions by using de novo double-membrane vesicle (autophagosome) formation to target a wide range of cytoplasmic material for vacuolar/lysosomal degradation. The Atg1 kinase is one of its key regulators, coordinating a complex signaling program to orchestrate autophagosome formation. Combining in vitro reconstitution and cell-based approaches, we demonstrate that Atg1 is activated by lipidated Atg8 (Atg8-PE), stimulating substrate phosphorylation along the growing autophagosomal membrane. Atg1-dependent phosphorylation of Atg13 triggers Atg1 complex dissociation, enabling rapid turnover of Atg1 complex subunits at the pre-autophagosomal structure (PAS). Moreover, Atg1 recruitment by Atg8-PE self-regulates Atg8-PE levels in the growing autophagosomal membrane by phosphorylating and thus inhibiting the Atg8-specific E2 and E3. Our work uncovers the molecular basis for positive and negative feedback imposed by Atg1 and how opposing phosphorylation and dephosphorylation events underlie the spatiotemporal regulation of autophagy.
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Affiliation(s)
- Anne Schreiber
- Cellular Degradation Systems Laboratory, The Francis Crick Institute, 1 Midland Road, NW1 1AT London, UK; Institute of Biochemistry, ETH Zürich, Otto-Stern-Weg 3, 8093 Zürich, Switzerland.
| | - Ben C Collins
- Institute of Molecular Systems Biology, ETH Zürich, Otto-Stern-Weg 3, 8093 Zürich, Switzerland; School of Biological Sciences, Queen's University of Belfast, 19 Chlorine Gardens, BT9 5DL Belfast, UK
| | - Colin Davis
- Cellular Degradation Systems Laboratory, The Francis Crick Institute, 1 Midland Road, NW1 1AT London, UK
| | - Radoslav I Enchev
- Institute of Biochemistry, ETH Zürich, Otto-Stern-Weg 3, 8093 Zürich, Switzerland; Visual Biochemistry Laboratory, The Francis Crick Institute, 1 Midland Road, NW1 1AT London, UK
| | - Angie Sedra
- Institute of Biochemistry, ETH Zürich, Otto-Stern-Weg 3, 8093 Zürich, Switzerland
| | - Rocco D'Antuono
- Crick Advanced Light Microscopy (CALM) STP, The Francis Crick Institute, 1 Midland Road, NW1 1AT London, UK
| | - Ruedi Aebersold
- Institute of Molecular Systems Biology, ETH Zürich, Otto-Stern-Weg 3, 8093 Zürich, Switzerland
| | - Matthias Peter
- Institute of Biochemistry, ETH Zürich, Otto-Stern-Weg 3, 8093 Zürich, Switzerland.
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Sechi S, Karimpour-Ghahnavieh A, Frappaolo A, Di Francesco L, Piergentili R, Schininà E, D’Avino PP, Giansanti MG. Identification of GOLPH3 Partners in Drosophila Unveils Potential Novel Roles in Tumorigenesis and Neural Disorders. Cells 2021; 10:cells10092336. [PMID: 34571985 PMCID: PMC8468827 DOI: 10.3390/cells10092336] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 09/01/2021] [Accepted: 09/03/2021] [Indexed: 12/28/2022] Open
Abstract
Golgi phosphoprotein 3 (GOLPH3) is a highly conserved peripheral membrane protein localized to the Golgi apparatus and the cytosol. GOLPH3 binding to Golgi membranes depends on phosphatidylinositol 4-phosphate [PI(4)P] and regulates Golgi architecture and vesicle trafficking. GOLPH3 overexpression has been correlated with poor prognosis in several cancers, but the molecular mechanisms that link GOLPH3 to malignant transformation are poorly understood. We recently showed that PI(4)P-GOLPH3 couples membrane trafficking with contractile ring assembly during cytokinesis in dividing Drosophila spermatocytes. Here, we use affinity purification coupled with mass spectrometry (AP-MS) to identify the protein-protein interaction network (interactome) of Drosophila GOLPH3 in testes. Analysis of the GOLPH3 interactome revealed enrichment for proteins involved in vesicle-mediated trafficking, cell proliferation and cytoskeleton dynamics. In particular, we found that dGOLPH3 interacts with the Drosophila orthologs of Fragile X mental retardation protein and Ataxin-2, suggesting a potential role in the pathophysiology of disorders of the nervous system. Our findings suggest novel molecular targets associated with GOLPH3 that might be relevant for therapeutic intervention in cancers and other human diseases.
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Affiliation(s)
- Stefano Sechi
- Istituto di Biologia e Patologia Molecolari del CNR, c/o Dipartimento di Biologia e Biotecnologie, Sapienza Università di Roma, Piazzale A. Moro 5, 00185 Roma, Italy; (S.S.); (A.K.-G.); (A.F.); (R.P.)
| | - Angela Karimpour-Ghahnavieh
- Istituto di Biologia e Patologia Molecolari del CNR, c/o Dipartimento di Biologia e Biotecnologie, Sapienza Università di Roma, Piazzale A. Moro 5, 00185 Roma, Italy; (S.S.); (A.K.-G.); (A.F.); (R.P.)
| | - Anna Frappaolo
- Istituto di Biologia e Patologia Molecolari del CNR, c/o Dipartimento di Biologia e Biotecnologie, Sapienza Università di Roma, Piazzale A. Moro 5, 00185 Roma, Italy; (S.S.); (A.K.-G.); (A.F.); (R.P.)
| | - Laura Di Francesco
- Dipartimento di Scienze Biochimiche A. Rossi Fanelli, Sapienza Università di Roma, Piazzale A. Moro 5, 00185 Roma, Italy; (L.D.F.); (E.S.)
| | - Roberto Piergentili
- Istituto di Biologia e Patologia Molecolari del CNR, c/o Dipartimento di Biologia e Biotecnologie, Sapienza Università di Roma, Piazzale A. Moro 5, 00185 Roma, Italy; (S.S.); (A.K.-G.); (A.F.); (R.P.)
| | - Eugenia Schininà
- Dipartimento di Scienze Biochimiche A. Rossi Fanelli, Sapienza Università di Roma, Piazzale A. Moro 5, 00185 Roma, Italy; (L.D.F.); (E.S.)
| | - Pier Paolo D’Avino
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK;
| | - Maria Grazia Giansanti
- Istituto di Biologia e Patologia Molecolari del CNR, c/o Dipartimento di Biologia e Biotecnologie, Sapienza Università di Roma, Piazzale A. Moro 5, 00185 Roma, Italy; (S.S.); (A.K.-G.); (A.F.); (R.P.)
- Correspondence: ; Tel.: +39-064-991-2555
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Zhang X, Du W, Zhang J, Zou Z, Ruan C. High-throughput profiling of diapause regulated genes from Trichogramma dendrolimi (Hymenoptera: Trichogrammatidae). BMC Genomics 2020; 21:864. [PMID: 33276726 PMCID: PMC7718664 DOI: 10.1186/s12864-020-07285-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Accepted: 11/26/2020] [Indexed: 11/10/2022] Open
Abstract
Background The parasitoid wasp, Trichogramma dendrolimi, can enter diapause at the prepupal stage. Thus, diapause is an efficient preservation method during the mass production of T. dendrolimi. Previous studies on diapause have mainly focused on ecological characteristics, so the molecular basis of diapause in T. dendrolimi is unknown. We compared transcriptomes of diapause and non-diapause T. dendrolimi to identify key genes and pathways involved in diapause development. Results Transcriptome sequencing was performed on diapause prepupae, pupae after diapause, non-diapause prepupae, and pupae. Analysis yielded a total of 87,022 transcripts with an average length of 1604 bp. By removing redundant sequences and those without significant BLAST hits, a non-redundant dataset was generated, containing 7593 sequences with an average length of 3351 bp. Among them, 5702 genes were differentially expressed. The result of Gene Ontology (GO) enrichment analysis revealed that regulation of transcription, DNA-templated, oxidation-reduction process, and signal transduction were significantly affected. Ten genes were selected for validation using quantitative real-time PCR (qPCR). The changes showed the same trend as between the qPCR and RNA-Seq results. Several genes were identified as involved in diapause, including ribosomal proteins, zinc finger proteins, homeobox proteins, forkhead box proteins, UDP-glucuronosyltransferase, Glutathione-S-transferase, p53, and DNA damage-regulated gene 1 (pdrg1). Genes related to lipid metabolism were also included. Conclusions We generated a large amount of transcriptome data from T. dendrolimi, providing a resource for future gene function research. The diapause-related genes identified help reveal the molecular mechanisms of diapause, in T. dendrolimi, and other insect species. Supplementary Information The online version contains supplementary material available at 10.1186/s12864-020-07285-4.
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Affiliation(s)
- Xue Zhang
- Engineering Research Center of Natural Enemies, Institute of Biological Control, Jilin Agricultural University, Changchun, 130118, China
| | - Wenmei Du
- Engineering Research Center of Natural Enemies, Institute of Biological Control, Jilin Agricultural University, Changchun, 130118, China
| | - Junjie Zhang
- Engineering Research Center of Natural Enemies, Institute of Biological Control, Jilin Agricultural University, Changchun, 130118, China
| | - Zhen Zou
- State Key Laboratory of Integrated Management of Pest Insect and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Changchun Ruan
- Engineering Research Center of Natural Enemies, Institute of Biological Control, Jilin Agricultural University, Changchun, 130118, China.
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9
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Bye-A-Jee H, Zaru R, Magrane M, Orchard S. Caenorhabditis elegans phosphatase complexes in UniProtKB and Complex Portal. FEBS J 2020; 287:2664-2684. [PMID: 31944606 DOI: 10.1111/febs.15213] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Revised: 11/25/2019] [Accepted: 01/13/2020] [Indexed: 02/06/2023]
Abstract
Phosphatases play an essential role in the regulation of protein phosphorylation. Less abundant than kinases, many phosphatases are components of one or more macromolecular complexes with different substrate specificities and specific functionalities. The expert scientific curation of phosphatase complexes for the UniProt and Complex Portal databases supports the whole scientific community by collating and organising small- and large-scale experimental data from the scientific literature into context-specific central resources, where the data can be freely accessed and used to further academic and translational research. In this review, we discuss how the diverse biological functions of phosphatase complexes are presented in UniProt and the Complex Portal, and how understanding the biological significance of phosphatase complexes in Caenorhabditis elegans offers insight into the mechanisms of substrate diversity in a variety of cellular and molecular processes.
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Affiliation(s)
- Hema Bye-A-Jee
- European Molecular Biology Laboratory, European Bioinformatics Institute (EMBL-EBI), Cambridge, UK
| | - Rossana Zaru
- European Molecular Biology Laboratory, European Bioinformatics Institute (EMBL-EBI), Cambridge, UK
| | - Michele Magrane
- European Molecular Biology Laboratory, European Bioinformatics Institute (EMBL-EBI), Cambridge, UK
| | - Sandra Orchard
- European Molecular Biology Laboratory, European Bioinformatics Institute (EMBL-EBI), Cambridge, UK
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- European Molecular Biology Laboratory, European Bioinformatics Institute (EMBL-EBI), Cambridge, UK.,SIB Swiss Institute of Bioinformatics, Centre Medical Universitaire, Geneva 4, Switzerland.,Protein Information Resource, Georgetown University Medical Center, Washington, DC, USA.,Protein Information Resource, University of Delaware, Newark, DE, USA
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10
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Chen H, Xu J, Wang P, Shu Q, Huang L, Guo J, Zhang X, Zhang H, Wang Y, Shen Z, Chen X, Zhang Q. Protein phosphatase 2 regulatory subunit B''Alpha silencing inhibits tumor cell proliferation in liver cancer. Cancer Med 2019; 8:7741-7753. [PMID: 31647192 PMCID: PMC6912040 DOI: 10.1002/cam4.2620] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2019] [Revised: 09/29/2019] [Accepted: 10/06/2019] [Indexed: 12/24/2022] Open
Abstract
Aim To explore the effects of protein phosphatase 2 regulatory subunit B''Alpha (PPP2R3A) on the proliferation and migration of liver cancer cells. Methods Expression of PPP2R3A in tumor tissues of hepatocellular carcinoma (HCC) patients was detected by immunohistochemistry and western blotting. In two liver cancer cell lines (HepG2 and HuH7), PPP2R3A expression was silenced and then overexpression with PPP2R3A lentiviral vectors, and the effects of PPP2R3A knockdown or overexpression on the proliferation, cell cycle, migration, and invasion of HCC cells were determined in vitro. In a xenograft cancer model in nude mice, the in vivo effects of PPP2R3A knockdown on tumor growth and cancer cell proliferation were evaluated. Results PPP2R3A expression was found in tumor foci in six of eight HCC samples, at a level higher than that in the adjacent para‐tumor tissues. PPP2R3A expression was observed primarily in the cytoplasm of the cancer cells. Knockdown of PPP2R3A resulted in significant inhibition of hepatoma cell proliferation (P < .05), migration (P < .01), and invasion (P < .01) as well as a significant delay in the G1/S transition in both liver cancer lines (P < .05) and increased p53 expression. Conversely, overexpression of PPP2R3A promoted the proliferation (P < .05) and altered cell cycle progression (P < .05) of both liver cancer cell lines. In vivo, PPP2R3A knockdown in liver cancer cells led to significant reductions in the tumor volume (P < .001) and the expression of Ki‐67 in tumor tissues (P < .05). Conclusion PPP2R3A may play a role in liver cancer via the regulation of tumor cell proliferation and invasion.
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Affiliation(s)
- Huijuan Chen
- Department of Liver Transplantation, The Third Medical Centre, Chinese PLA (People's Liberation Army) General Hospital, Beijing, China.,Graduate School, Anhui Medical University, Hefei, China
| | - Jing Xu
- National Translational Science Center for Molecular Medicine & Department of Cell Biology, State Key Laboratory of Cancer Biology, Fourth Military Medical University, Xi'an, China
| | - Peixiao Wang
- Department of Gastroenterology, Henan Children's Hospital, Zhengzhou, China
| | - Qingming Shu
- Pathology Department, The Third Medical Centre, Chinese PLA (People's Liberation Army) General Hospital, Beijing, China
| | - Lihong Huang
- Medical Department, The Third Medical Centre, Chinese PLA (People's Liberation Army) General Hospital, Beijing, China
| | - Jing Guo
- Medical Department, The Third Medical Centre, Chinese PLA (People's Liberation Army) General Hospital, Beijing, China
| | - Xuyi Zhang
- Medical Department, The Third Medical Centre, Chinese PLA (People's Liberation Army) General Hospital, Beijing, China
| | - Hongying Zhang
- Medical Department, The Third Medical Centre, Chinese PLA (People's Liberation Army) General Hospital, Beijing, China
| | - Ying Wang
- Department of Liver Transplantation, The Third Medical Centre, Chinese PLA (People's Liberation Army) General Hospital, Beijing, China
| | - Zhongyang Shen
- Department of Liver Transplantation, The Third Medical Centre, Chinese PLA (People's Liberation Army) General Hospital, Beijing, China.,Department of Transplantation Surgery, Tianjin First Central Hospital, Tianjin, China
| | - Xinguo Chen
- Department of Liver Transplantation, The Third Medical Centre, Chinese PLA (People's Liberation Army) General Hospital, Beijing, China
| | - Qing Zhang
- Department of Liver Transplantation, The Third Medical Centre, Chinese PLA (People's Liberation Army) General Hospital, Beijing, China
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11
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Penfluridol as a Candidate of Drug Repurposing for Anticancer Agent. Molecules 2019; 24:molecules24203659. [PMID: 31614431 PMCID: PMC6832311 DOI: 10.3390/molecules24203659] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 09/29/2019] [Accepted: 10/08/2019] [Indexed: 12/24/2022] Open
Abstract
Penfluridol has robust antipsychotic efficacy and is a first-generation diphenylbutylpiperidine. Its effects last for several days after a single oral dose and it can be administered once a week to provide better compliance and symptom control. Recently; strong antitumour effects for penfluridol were discovered in various cancer cell lines; such as breast; pancreatic; glioblastoma; and lung cancer cells via several distinct mechanisms. Therefore; penfluridol has drawn much attention as a potentially novel anti-tumour agent. In addition; the anti-cancer effects of penfluridol have been demonstrated in vivo: results showed slight changes in the volume and weight of organs at doses tested in animals. This paper outlines the potential for penfluridol to be developed as a next-generation anticancer drug.
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12
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Villegas SN, Ferres-Marco D, Domínguez M. Using Drosophila Models and Tools to Understand the Mechanisms of Novel Human Cancer Driver Gene Function. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1167:15-35. [PMID: 31520347 DOI: 10.1007/978-3-030-23629-8_2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
The formation, overgrowth and metastasis of tumors comprise a complex series of cellular and molecular events resulting from the combined effects of a variety of aberrant signaling pathways, mutations, and epigenetic alterations. Modeling this complexity in vivo requires multiple genes to be manipulated simultaneously, which is technically challenging. Here, we analyze how Drosophila research can further contribute to identifying pathways and elucidating mechanisms underlying novel cancer driver (risk) genes associated with tumor growth and metastasis in humans.
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Affiliation(s)
- Santiago Nahuel Villegas
- Instituto de Neurociencias, Consejo Superior de Investigaciones Cientificas (CSIC) and Universidad Miguel Hernández (UMH), Alicante, Spain.
| | - Dolors Ferres-Marco
- Instituto de Neurociencias, Consejo Superior de Investigaciones Cientificas (CSIC) and Universidad Miguel Hernández (UMH), Alicante, Spain.
| | - María Domínguez
- Instituto de Neurociencias, Consejo Superior de Investigaciones Cientificas (CSIC) and Universidad Miguel Hernández (UMH), Alicante, Spain
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13
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Zimmermann A, Kainz K, Hofer SJ, Bauer MA, Schroeder S, Dengjel J, Pietrocola F, Kepp O, Ruckenstuhl C, Eisenberg T, Sigrist SJ, Madeo F, Kroemer G, Carmona-Gutierrez D. Targeting GATA transcription factors - a novel strategy for anti-aging interventions? MICROBIAL CELL 2019; 6:212-216. [PMID: 31114793 PMCID: PMC6506692 DOI: 10.15698/mic2019.05.676] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
GATA transcription factors (TFs) are a conserved family of zinc-finger TFs that fulfill diverse functions across eukaryotes. Accumulating evidence suggests that GATA TFs also play a role in lifespan regulation. In a recent study, we have identified a natural compound, 4,4' dimethoxychalcone (DMC) that extends lifespan depending on reduced activity of distinct GATA TFs. Prolonged lifespan by DMC treatment depends on autophagy, a protective cellular self-cleaning mechanism. In yeast, DMC reduces the activity of the GATA TF Gln3 and, at the same time, deletion of GLN3 increases autophagy levels during cellular aging per se. Here, we examine current data on the involvement of GATA TFs in the regulation of both autophagy and lifespan in different organisms and explore, if GATA TFs are suitable targets for anti-aging interventions.
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Affiliation(s)
- Andreas Zimmermann
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, Graz, Austria.,Division of Endocrinology and Diabetology, Department of Internal Medicine, Medical University of Graz, Graz, Austria
| | - Katharina Kainz
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, Graz, Austria.,Division of Endocrinology and Diabetology, Department of Internal Medicine, Medical University of Graz, Graz, Austria
| | - Sebastian J Hofer
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, Graz, Austria.,BioTechMed Graz, Graz, Austria
| | - Maria A Bauer
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, Graz, Austria
| | - Sabrina Schroeder
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, Graz, Austria
| | - Jörn Dengjel
- Department of Biology, Université de Fribourg, Switzerland
| | | | - Oliver Kepp
- Equipe 11 labellisée Ligue contre le Cancer, Centre de Recherche des Cordeliers, INSERM U 1138, Paris, France.,Metabolomics and Cell Biology Platforms, Gustave Roussy Comprehensive Cancer Center, Villejuif, France.,Université de Paris, Paris, France.,Sorbonne Université Paris, France
| | | | - Tobias Eisenberg
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, Graz, Austria.,BioTechMed Graz, Graz, Austria.,BioHealth Graz, Graz, Austria.,Central Lab Gracia, NAWI Graz, University of Graz, Graz, Austria
| | - Stephan J Sigrist
- Institute for Biology/Genetics, Freie Universität Berlin, Berlin, Germany
| | - Frank Madeo
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, Graz, Austria.,BioTechMed Graz, Graz, Austria.,BioHealth Graz, Graz, Austria
| | - Guido Kroemer
- Equipe 11 labellisée Ligue contre le Cancer, Centre de Recherche des Cordeliers, INSERM U 1138, Paris, France.,Metabolomics and Cell Biology Platforms, Gustave Roussy Comprehensive Cancer Center, Villejuif, France.,Université de Paris, Paris, France.,Sorbonne Université Paris, France.,Pôle de Biologie, Hôpital Européen Georges Pompidou, Paris, France.,Suzhou Institute for Systems Biology, Chinese Academy of Sciences, Suzhou, China.,Karolinska Institute, Department of Women's and Children's Health, Karolinska University Hospital, Stockholm, Sweden
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14
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Wang Z, Liu G, Jiang J. Profiling of apoptosis- and autophagy-associated molecules in human lung cancer A549 cells in response to cisplatin treatment using stable isotope labeling with amino acids in cell culture. Int J Oncol 2019; 54:1071-1085. [PMID: 30664195 DOI: 10.3892/ijo.2019.4690] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Accepted: 10/01/2018] [Indexed: 11/06/2022] Open
Abstract
Cis‑diammine‑dichloro‑platinum II‑based adjuvant chemotherapy provides an alternative therapy to improve the survival of patients with lung tumors, especially those with non‑small cell lung cancer (NSCLC). However, drug resistance is a large clinical problem and its underlying mechanism remains unclear. In the present study, NSCLC A549 cells were treated with a low concentration of cisplatin in order to observe and determine the development of chemoresistance, via growth curves, colony forming assays and apoptosis assays. Then the induction of autophagy was examined in the cisplatin‑treated A549 cells with a fluorescence reporter. Profiled proteins in the cisplatin‑treated A549 cells were also assessed using the stable isotope labeling by amino acids in cell culture (SILAC) method, and then the differentially expressed molecules were verified. The results demonstrated that A549 cells became less sensitive to cisplatin [resistant A549 cells (A549R)] following 20 passages in the medium containing a low concentration of cisplatin, with less apoptotic cells post‑cisplatin treatment. A549R cells grew more efficiently in the cisplatin medium, with more colony formation and more cells migrating across the baseline. In addition, NSCLC results demonstrated that more autophagy‑related proteins (ATGs) were expressed in the A549R cells. Furthermore, the western blotting results confirmed this upregulation of ATGs in A549R cells. In addition, two repeated SILAC screening experiments recognized 15 proteins [glucose‑regulated protein, 78 kDa (GRP78), heat shock protein 71, pre‑mRNA processing factor 19, polypyrimidine tract binding protein 1, translationally controlled tumor protein, Cathepsin D, Cytochrome c, thioredoxin domain containing 5, MutS homolog (MSH) 6, Annexin A2 (ANXA2), BRCA2 and Cyclin dependent kinase inhibitor 1A interacting protein, MSH2, protein phosphatase 2A 55 kDa regulatory subunit Bα, Rho glyceraldehyde‑3‑phosphate‑dissociation inhibitor 1 and ANXA4] that were upregulated by >1.5‑fold in heavy (H)‑ and light (L)‑labeled A549R cells. In addition, 16 and 14 proteins were downregulated by >1.5‑fold in the H‑ and L‑labeled A549R cells, respectively. The majority of the downregulated proteins were associated with apoptosis. In conclusion, the present study isolated a cisplatin‑resistant human lung cancer A549 cell clone, with reduced apoptosis and high levels of autophagy, in response to cisplatin treatment. In cisplatin‑resistant A549R cells, SILAC proteomics recognized the high expression of GRP78 and other proteins that are associated with anti‑apoptosis and/or autophagy promotion.
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Affiliation(s)
- Zongqiang Wang
- Department of Medical Services, China-Japan Union Hospital of Jilin University, Changchun, Jilin 130033, P.R. China
| | - Guifeng Liu
- Department of Radiology, China-Japan Union Hospital of Jilin University, Changchun, Jilin 130033, P.R. China
| | - Jinlan Jiang
- Science Research Center, Department of Orthopedics, China-Japan Union Hospital of Jilin University, Changchun, Jilin 130033, P.R. China
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15
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Yin J, Ren W, Chen S, Li Y, Han H, Gao J, Liu G, Wu X, Li T, Woo Kim S, Yin Y. Metabolic Regulation of Methionine Restriction in Diabetes. Mol Nutr Food Res 2018; 62:e1700951. [PMID: 29603632 DOI: 10.1002/mnfr.201700951] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2017] [Revised: 01/25/2018] [Indexed: 12/16/2022]
Abstract
Although the effects of dietary methionine restriction have been investigated in the physiology of aging and diseases related to oxidative stress, the relationship between methionine restriction (MR) and the development of metabolic disorders has not been explored extensively. This review summarizes studies of the possible involvement of dietary methionine restriction in improving insulin resistance, glucose homeostasis, oxidative stress, lipid metabolism, the pentose phosphate pathway (PPP), and inflammation, with an emphasis on the fibroblast growth factor 21 and protein phosphatase 2A signals and autophagy in diabetes. Diets deficient in methionine may be a useful nutritional strategy in patients with diabetes.
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Affiliation(s)
- Jie Yin
- Guangdong Provincial Key Laboratory of Animal Nutrition Control, Institute of Subtropical Animal Nutrition and Feed, College of Animal Science, South China Agricultural University, Guangzhou, China.,Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central, Ministry of Agriculture, Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan, China.,University of Chinese Academy of Sciences, Beijing, PR, China
| | - Wenkai Ren
- Guangdong Provincial Key Laboratory of Animal Nutrition Control, Institute of Subtropical Animal Nutrition and Feed, College of Animal Science, South China Agricultural University, Guangzhou, China.,Jiangsu Co-Innovation Center for Important Animal Infectious Diseases and Zoonoses, Joint International Research Laboratory of Agriculture and Agri-Product, Safety of Ministry of Education of China, College of Veterinary Medicine, Yangzhou University, Yangzhou, China
| | - Shuai Chen
- Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central, Ministry of Agriculture, Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan, China.,University of Chinese Academy of Sciences, Beijing, PR, China
| | - Yuying Li
- Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central, Ministry of Agriculture, Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan, China.,University of Chinese Academy of Sciences, Beijing, PR, China
| | - Hui Han
- Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central, Ministry of Agriculture, Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan, China.,University of Chinese Academy of Sciences, Beijing, PR, China
| | - Jing Gao
- Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central, Ministry of Agriculture, Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan, China.,University of Chinese Academy of Sciences, Beijing, PR, China
| | - Gang Liu
- Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central, Ministry of Agriculture, Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan, China
| | - Xin Wu
- Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central, Ministry of Agriculture, Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan, China.,Hunan Co-Innovation Center of Animal Production Safety, Changsha, PR, China
| | - Tiejun Li
- Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central, Ministry of Agriculture, Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan, China.,Hunan Co-Innovation Center of Animal Production Safety, Changsha, PR, China
| | - Sung Woo Kim
- Department of Animal Science, North Carolina State University, Raleigh, NC, USA
| | - Yulong Yin
- Guangdong Provincial Key Laboratory of Animal Nutrition Control, Institute of Subtropical Animal Nutrition and Feed, College of Animal Science, South China Agricultural University, Guangzhou, China.,Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central, Ministry of Agriculture, Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan, China.,Hunan Co-Innovation Center of Animal Production Safety, Changsha, PR, China
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16
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Huang P, Wang S, Weng D, Xu L. Alpha4-overexpressing HL7702 cells can counteract microcystin-LR effects on cytoskeletal structure. ENVIRONMENTAL TOXICOLOGY 2018; 33:978-987. [PMID: 29984889 DOI: 10.1002/tox.22585] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Revised: 05/28/2018] [Accepted: 05/28/2018] [Indexed: 06/08/2023]
Abstract
Our previous studies indicated that α4 was involved in the toxicity of MC-LR on the cytoskeleton via the change of PP2A activity in HEK 293. To explore the role of α4 in MC-LR toxicity via PP2A regulation in different cell lines, the HL7702 cell overexpressing α4 protein was exposed to MC-LR, and the change of PP2A, cytoskeletal structure, and cytoskeleton-related proteins were investigated. The results showed that PP2A activity was decreased, PP2A/C subunit expression and phosphorylation (Tyr307) increased significantly, but methylation (Leu 309)clearly decreased. The structure of the actin filaments and microtubules (MTs) remained unchanged, and the expression and phosphorylation of the cytoskeleton-related proteins showed different changes. In addition, the main components of the MAPK pathway, JNK, P38, and ERK1/2, were activated together. Our results indicated that elevated α4 expression did confer some resistance to MC-LR-induced cytoskeletal changes, but the responses of different cell lines to MC-LR, under the α4-overexpression condition, are not exactly the same.
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Affiliation(s)
- Pu Huang
- Department of Biochemistry, School of Medicine, Zhejiang University, Hangzhou, China
| | - Sha Wang
- Department of Biochemistry, School of Medicine, Zhejiang University, Hangzhou, China
| | - Dengpo Weng
- Department of Biochemistry, School of Medicine, Zhejiang University, Hangzhou, China
| | - Lihong Xu
- Department of Biochemistry, School of Medicine, Zhejiang University, Hangzhou, China
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17
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Cdc14 Phosphatase Promotes TORC1-Regulated Autophagy in Yeast. J Mol Biol 2018; 430:1671-1684. [DOI: 10.1016/j.jmb.2018.04.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 04/06/2018] [Accepted: 04/06/2018] [Indexed: 12/20/2022]
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18
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Pengo N, Agrotis A, Prak K, Jones J, Ketteler R. A reversible phospho-switch mediated by ULK1 regulates the activity of autophagy protease ATG4B. Nat Commun 2017; 8:294. [PMID: 28821708 PMCID: PMC5562857 DOI: 10.1038/s41467-017-00303-2] [Citation(s) in RCA: 101] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Accepted: 06/20/2017] [Indexed: 12/26/2022] Open
Abstract
Upon induction of autophagy, the ubiquitin-like protein LC3 is conjugated to phosphatidylethanolamine (PE) on the inner and outer membrane of autophagosomes to allow cargo selection and autophagosome formation. LC3 undergoes two processing steps, the proteolytic cleavage of pro-LC3 and the de-lipidation of LC3-PE from autophagosomes, both executed by the same cysteine protease ATG4. How ATG4 activity is regulated to co-ordinate these events is currently unknown. Here we find that ULK1, a protein kinase activated at the autophagosome formation site, phosphorylates human ATG4B on serine 316. Phosphorylation at this residue results in inhibition of its catalytic activity in vitro and in vivo. On the other hand, phosphatase PP2A-PP2R3B can remove this inhibitory phosphorylation. We propose that the opposing activities of ULK1-mediated phosphorylation and PP2A-mediated dephosphorylation provide a phospho-switch that regulates the cellular activity of ATG4B to control LC3 processing.Upon autophagy induction, LC3 is cleaved by the protease ATG4 and conjugated to the autophagosomal membrane; however, its removal is mediated by the same protease. Here the authors show that ULK1-mediated phosphorylation and PP2A-mediated dephosphorylation of ATG4 regulates its cellular activity to control LC3 processing.
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Affiliation(s)
- N Pengo
- MRC Laboratory for Molecular Cell Biology, University College London, Gower Street, London, WC1E 6BT, UK
| | - A Agrotis
- MRC Laboratory for Molecular Cell Biology, University College London, Gower Street, London, WC1E 6BT, UK
| | - K Prak
- MRC Laboratory for Molecular Cell Biology, University College London, Gower Street, London, WC1E 6BT, UK
| | - J Jones
- MRC Laboratory for Molecular Cell Biology, University College London, Gower Street, London, WC1E 6BT, UK
| | - R Ketteler
- MRC Laboratory for Molecular Cell Biology, University College London, Gower Street, London, WC1E 6BT, UK.
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19
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Mitchell CL, Latuszek CE, Vogel KR, Greenlund IM, Hobmeier RE, Ingram OK, Dufek SR, Pecore JL, Nip FR, Johnson ZJ, Ji X, Wei H, Gailing O, Werner T. α-amanitin resistance in Drosophila melanogaster: A genome-wide association approach. PLoS One 2017; 12:e0173162. [PMID: 28241077 PMCID: PMC5328632 DOI: 10.1371/journal.pone.0173162] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Accepted: 02/15/2017] [Indexed: 11/17/2022] Open
Abstract
We investigated the mechanisms of mushroom toxin resistance in the Drosophila Genetic Reference Panel (DGRP) fly lines, using genome-wide association studies (GWAS). While Drosophila melanogaster avoids mushrooms in nature, some lines are surprisingly resistant to α-amanitin—a toxin found solely in mushrooms. This resistance may represent a pre-adaptation, which might enable this species to invade the mushroom niche in the future. Although our previous microarray study had strongly suggested that pesticide-metabolizing detoxification genes confer α-amanitin resistance in a Taiwanese D. melanogaster line Ama-KTT, none of the traditional detoxification genes were among the top candidate genes resulting from the GWAS in the current study. Instead, we identified Megalin, Tequila, and widerborst as candidate genes underlying the α-amanitin resistance phenotype in the North American DGRP lines, all three of which are connected to the Target of Rapamycin (TOR) pathway. Both widerborst and Tequila are upstream regulators of TOR, and TOR is a key regulator of autophagy and Megalin-mediated endocytosis. We suggest that endocytosis and autophagy of α-amanitin, followed by lysosomal degradation of the toxin, is one of the mechanisms that confer α-amanitin resistance in the DGRP lines.
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Affiliation(s)
- Chelsea L Mitchell
- Department of Biological Sciences, Michigan Technological University, 1400 Townsend Dr., Houghton, MI, United States of America
| | - Catrina E Latuszek
- Department of Biological Sciences, Michigan Technological University, 1400 Townsend Dr., Houghton, MI, United States of America
| | - Kara R Vogel
- Department of Neurology, University of Wisconsin School of Medicine and Public Health, 1300 University Ave., Madison, WI, United States of America
| | - Ian M Greenlund
- Department of Biological Sciences, Michigan Technological University, 1400 Townsend Dr., Houghton, MI, United States of America
| | - Rebecca E Hobmeier
- Department of Biological Sciences, Michigan Technological University, 1400 Townsend Dr., Houghton, MI, United States of America
| | - Olivia K Ingram
- Department of Biological Sciences, Michigan Technological University, 1400 Townsend Dr., Houghton, MI, United States of America
| | - Shannon R Dufek
- Department of Biological Sciences, Michigan Technological University, 1400 Townsend Dr., Houghton, MI, United States of America
| | - Jared L Pecore
- Department of Biological Sciences, Michigan Technological University, 1400 Townsend Dr., Houghton, MI, United States of America
| | - Felicia R Nip
- College of Human Medicine, Michigan State University, Clinical Center, East Lansing, MI, United States of America
| | - Zachary J Johnson
- U.S. Forest Service, Salt Lake Ranger District 6944 S, 3000 E, Salt Lake City, UT, United States of America
| | - Xiaohui Ji
- School of Forest Resources and Environmental Sciences, Michigan Technological University, 1400 Townsend Dr., Houghton, MI, United States of America
| | - Hairong Wei
- School of Forest Resources and Environmental Sciences, Michigan Technological University, 1400 Townsend Dr., Houghton, MI, United States of America
| | - Oliver Gailing
- School of Forest Resources and Environmental Sciences, Michigan Technological University, 1400 Townsend Dr., Houghton, MI, United States of America
| | - Thomas Werner
- Department of Biological Sciences, Michigan Technological University, 1400 Townsend Dr., Houghton, MI, United States of America
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20
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Huang P, Wang B, Wang X, Xing M, Guo Z, Xu L. HEK293 cells exposed to microcystin-LR show reduced protein phosphatase 2A activity and more stable cytoskeletal structure when overexpressing α4 protein. ENVIRONMENTAL TOXICOLOGY 2017; 32:255-264. [PMID: 26784437 DOI: 10.1002/tox.22230] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2015] [Revised: 12/04/2015] [Accepted: 12/06/2015] [Indexed: 06/05/2023]
Abstract
Microcystin-LR (MC-LR) is one of the most toxic members of microcystins released by freshwater cyanobacterial. The major mechanism of MC-LR toxicity has been attributed to its inhibition of protein phosphatases 1 (PP1) and 2A (PP2A). In our prior research, α4 protein, a regulator of PP2A, was found not only crucial for PP2A regulation but also for the overall response of HEK 293 cells encountering MC-LR. To explore the role of α4 in MC-LR toxicity via PP2A regulation, here, HEK 293 cells overexpressing α4 protein were exposed to MC-LR and PP2A, cytoskeletal organization, and cytoskeleton-related proteins were investigated. The results showed that PP2A activity decreased and PP2A/C subunit expression and phosphorylation at Tyr307 increased significantly in the group exposed to high MC-LR. Vimentin IF became concentrated and formed perinuclear bundles. However, the assembly of actin filament and microtubules remained unchanged and the expression and phosphorylation of the cytoskeleton-related proteins HSP27 and VASP did not increase significantly. Some of these results differ from those of our previous study in which normal HEK293 cells were exposed to MC-LR. Our results indicate that elevated α4 expression confers some resistance to MC-LR-induced cytoskeletal change These new findings provide helpful insights into the mechanism of MC-LR toxicity and the role of α4 in regulating PP2A function. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 255-264, 2017.
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Affiliation(s)
- Pu Huang
- Department of Biochemistry, School of Medicine, Zhejiang University, Hangzhou, 310058, China
| | - Beilei Wang
- Department of Biochemistry, School of Medicine, Zhejiang University, Hangzhou, 310058, China
| | - Xiaofeng Wang
- Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou, 310051, China
| | - Mingluan Xing
- Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou, 310051, China
| | - Zonglou Guo
- Department of Biosystem Engineering, College of Biosystem Engineering and Food Science, Zhejiang University, Hangzhou, 310058, China
| | - Lihong Xu
- Department of Biochemistry, School of Medicine, Zhejiang University, Hangzhou, 310058, China
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Bandyopadhyay M, Arbet S, Bishop CP, Bidwai AP. Drosophila Protein Kinase CK2: Genetics, Regulatory Complexity and Emerging Roles during Development. Pharmaceuticals (Basel) 2016; 10:E4. [PMID: 28036067 PMCID: PMC5374408 DOI: 10.3390/ph10010004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Revised: 12/12/2016] [Accepted: 12/19/2016] [Indexed: 01/06/2023] Open
Abstract
CK2 is a Ser/Thr protein kinase that is highly conserved amongst all eukaryotes. It is a well-known oncogenic kinase that regulates vital cell autonomous functions and animal development. Genetic studies in the fruit fly Drosophila are providing unique insights into the roles of CK2 in cell signaling, embryogenesis, organogenesis, neurogenesis, and the circadian clock, and are revealing hitherto unknown complexities in CK2 functions and regulation. Here, we review Drosophila CK2 with respect to its structure, subunit diversity, potential mechanisms of regulation, developmental abnormalities linked to mutations in the gene encoding CK2 subunits, and emerging roles in multiple aspects of eye development. We examine the Drosophila CK2 "interaction map" and the eye-specific "transcriptome" databases, which raise the prospect that this protein kinase has many additional targets in the developing eye. We discuss the possibility that CK2 functions during early retinal neurogenesis in Drosophila and mammals bear greater similarity than has been recognized, and that this conservation may extend to other developmental programs. Together, these studies underscore the immense power of the Drosophila model organism to provide new insights and avenues to further investigate developmentally relevant targets of this protein kinase.
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Affiliation(s)
| | - Scott Arbet
- Department of Biology, West Virginia University, Morgantown, WV 26506, USA.
| | - Clifton P Bishop
- Department of Biology, West Virginia University, Morgantown, WV 26506, USA.
| | - Ashok P Bidwai
- Department of Biology, West Virginia University, Morgantown, WV 26506, USA.
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22
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Orchestrated Action of PP2A Antagonizes Atg13 Phosphorylation and Promotes Autophagy after the Inactivation of TORC1. PLoS One 2016; 11:e0166636. [PMID: 27973551 PMCID: PMC5156417 DOI: 10.1371/journal.pone.0166636] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2016] [Accepted: 11/01/2016] [Indexed: 12/30/2022] Open
Abstract
Target of rapamycin complex 1 (TORC1) phosphorylates autophagy-related Atg13 and represses autophagy under nutrient-rich conditions. However, when TORC1 becomes inactive upon nutrient depletion or treatment with the TORC1 inhibitor rapamycin, Atg13 dephosphorylation occurs rapidly, and autophagy is induced. At present, the phosphatases involved in Atg13 dephosphorylation remain unknown. Here, we show that two protein phosphatase 2A (PP2A) phosphatases, PP2A-Cdc55 and PP2A-Rts1, which are activated by inactivation of TORC1, are required for sufficient Atg13 dephosphorylation and autophagy induction after TORC1 inactivation in budding yeast. After rapamycin treatment, dephosphorylation of Atg13, activation of Atg1 kinase, pre-autophagosomal structure (PAS) formation and autophagy induction are all impaired in PP2A-deleted cells. Conversely, overexpression of non-phosphorylatable Atg13 suppressed defects in autophagy in PP2A mutant. This study revealed that the orchestrated action of PP2A antagonizes Atg13 phosphorylation and promotes autophagy after the inactivation of TORC1.
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23
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Advances in Autophagy Regulatory Mechanisms. Cells 2016; 5:cells5020024. [PMID: 27187479 PMCID: PMC4931673 DOI: 10.3390/cells5020024] [Citation(s) in RCA: 96] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2016] [Revised: 04/20/2016] [Accepted: 05/05/2016] [Indexed: 12/19/2022] Open
Abstract
Autophagy plays a critical role in cell metabolism by degrading and recycling internal components when challenged with limited nutrients. This fundamental and conserved mechanism is based on a membrane trafficking pathway in which nascent autophagosomes engulf cytoplasmic cargo to form vesicles that transport their content to the lysosome for degradation. Based on this simple scheme, autophagy modulates cellular metabolism and cytoplasmic quality control to influence an unexpectedly wide range of normal mammalian physiology and pathophysiology. In this review, we summarise recent advancements in three broad areas of autophagy regulation. We discuss current models on how autophagosomes are initiated from endogenous membranes. We detail how the uncoordinated 51-like kinase (ULK) complex becomes activated downstream of mechanistic target of rapamycin complex 1 (MTORC1). Finally, we summarise the upstream signalling mechanisms that can sense amino acid availability leading to activation of MTORC1.
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24
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Noda NN, Mizushima N. Atg101: Not Just an Accessory Subunit in the Autophagy-initiation Complex. Cell Struct Funct 2016; 41:13-20. [DOI: 10.1247/csf.15013] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Affiliation(s)
- Nobuo N. Noda
- Laboratory of Structural Chemistry and Biology, Institute of Microbial Chemistry (BIKAKEN)
| | - Noboru Mizushima
- Department of Biochemistry and Molecular Biology, Graduate School of Medicine, The University of Tokyo
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25
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Wesselborg S, Stork B. Autophagy signal transduction by ATG proteins: from hierarchies to networks. Cell Mol Life Sci 2015; 72:4721-57. [PMID: 26390974 PMCID: PMC4648967 DOI: 10.1007/s00018-015-2034-8] [Citation(s) in RCA: 165] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2015] [Revised: 08/13/2015] [Accepted: 08/31/2015] [Indexed: 02/07/2023]
Abstract
Autophagy represents an intracellular degradation process which is involved in both cellular homeostasis and disease settings. In the last two decades, the molecular machinery governing this process has been characterized in detail. To date, several key factors regulating this intracellular degradation process have been identified. The so-called autophagy-related (ATG) genes and proteins are central to this process. However, several additional molecules contribute to the outcome of an autophagic response. Several review articles describing the molecular process of autophagy have been published in the recent past. In this review article we would like to add the most recent findings to this knowledge, and to give an overview of the network character of the autophagy signaling machinery.
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Affiliation(s)
- Sebastian Wesselborg
- Institute of Molecular Medicine I, Heinrich-Heine-University, Universitätsstr. 1, Building 23.12, 40225, Düsseldorf, Germany
| | - Björn Stork
- Institute of Molecular Medicine I, Heinrich-Heine-University, Universitätsstr. 1, Building 23.12, 40225, Düsseldorf, Germany.
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26
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Zhang Z, Guo M, Zhao S, Xu W, Shao J, Zhang F, Wu L, Lu Y, Zheng S. The update on transcriptional regulation of autophagy in normal and pathologic cells: A novel therapeutic target. Biomed Pharmacother 2015; 74:17-29. [DOI: 10.1016/j.biopha.2015.06.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Accepted: 06/15/2015] [Indexed: 02/08/2023] Open
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27
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Patergnani S, Missiroli S, Marchi S, Giorgi C. Mitochondria-Associated Endoplasmic Reticulum Membranes Microenvironment: Targeting Autophagic and Apoptotic Pathways in Cancer Therapy. Front Oncol 2015; 5:173. [PMID: 26284195 PMCID: PMC4515599 DOI: 10.3389/fonc.2015.00173] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Accepted: 07/10/2015] [Indexed: 12/11/2022] Open
Abstract
Autophagy is a tightly regulated catabolic pathway that terminates in the lysosomal compartment after the formation of a cytoplasmic vacuole that engulfs macromolecules and organelles. Notably, autophagy is associated with several human pathophysiological conditions, playing either a cytoprotective or cytopathic role. Many studies have investigated the role of autophagy in cancer. However, whether autophagy suppresses tumorigenesis or provides cancer cells with a rescue mechanism under unfavorable conditions remains unclear. Mitochondria-associated membranes (MAMs) are juxtaposed between the endoplasmic reticulum and mitochondria and have been identified as critical hubs in the regulation of apoptosis and tumor growth. One key function of MAMs is to provide asylum to a number of proteins with tumor suppressor and oncogenic properties. Accordingly, mechanistic studies during tumor progression suggest a strong involvement of these proteins at various steps of the autophagic process. This paper discusses the present state of our knowledge about the intimate molecular networks between MAMs and autophagy in cancer cells and addresses how these networks might be manipulated to improve anticancer therapeutics.
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Affiliation(s)
- Simone Patergnani
- Laboratory for Technologies of Advanced Therapies (LTTA), Section of Pathology, Oncology and Experimental Biology, Department of Morphology, Surgery and Experimental Medicine, University of Ferrara , Ferrara , Italy
| | - Sonia Missiroli
- Laboratory for Technologies of Advanced Therapies (LTTA), Section of Pathology, Oncology and Experimental Biology, Department of Morphology, Surgery and Experimental Medicine, University of Ferrara , Ferrara , Italy
| | - Saverio Marchi
- Laboratory for Technologies of Advanced Therapies (LTTA), Section of Pathology, Oncology and Experimental Biology, Department of Morphology, Surgery and Experimental Medicine, University of Ferrara , Ferrara , Italy
| | - Carlotta Giorgi
- Laboratory for Technologies of Advanced Therapies (LTTA), Section of Pathology, Oncology and Experimental Biology, Department of Morphology, Surgery and Experimental Medicine, University of Ferrara , Ferrara , Italy
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28
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Ma J, Feng Y, Xie W, Li X. PP2A (PR65) in Silver Carp: cDNA Cloning and Expression Analysis. J Biochem Mol Toxicol 2015; 29:399-409. [DOI: 10.1002/jbt.21706] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Revised: 02/07/2015] [Accepted: 03/01/2015] [Indexed: 12/27/2022]
Affiliation(s)
- Junguo Ma
- College of Life Science; Henan Normal University; Xinxiang Henan 453007 China
| | - Yiyi Feng
- College of Life Science; Henan Normal University; Xinxiang Henan 453007 China
| | - Wenjie Xie
- College of Life Science; Henan Normal University; Xinxiang Henan 453007 China
| | - Xiaoyu Li
- College of Life Science; Henan Normal University; Xinxiang Henan 453007 China
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AMBRA1 links autophagy to cell proliferation and tumorigenesis by promoting c-Myc dephosphorylation and degradation. Nat Cell Biol 2014; 17:20-30. [PMID: 25438055 PMCID: PMC4976803 DOI: 10.1038/ncb3072] [Citation(s) in RCA: 158] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2014] [Accepted: 10/23/2014] [Indexed: 02/06/2023]
Abstract
Inhibition of a main regulator of cell metabolism, the protein kinase mTOR, induces autophagy and inhibits cell proliferation. However, the molecular pathways involved in the cross-talk between these two mTOR-dependent cell processes are largely unknown. Here we show that the scaffold protein AMBRA1, a member of the autophagy signalling network and a downstream target of mTOR, regulates cell proliferation by facilitating the dephosphorylation and degradation of the proto-oncogene C-MYC. We found that AMBRA1 favors the interaction between C-MYC and its phosphatase PP2A and that, when mTOR is inhibited, it enhances PP2A activity on this specific target, thereby reducing the cell division rate. As expected, such a de-regulation of C-MYC correlates with increased tumorigenesis in AMBRA1-defective systems, thus supporting a role for AMBRA1 as a haploinsufficient tumour suppressor gene.
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30
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Wang H, Liu J, Lin S, Wang B, Xing M, Guo Z, Xu L. MCLR-induced PP2A inhibition and subsequent Rac1 inactivation and hyperphosphorylation of cytoskeleton-associated proteins are involved in cytoskeleton rearrangement in SMMC-7721 human liver cancer cell line. CHEMOSPHERE 2014; 112:141-153. [PMID: 25048900 DOI: 10.1016/j.chemosphere.2014.03.130] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2013] [Revised: 03/26/2014] [Accepted: 03/27/2014] [Indexed: 06/03/2023]
Abstract
Cyanobacteria-derived toxin microcystin-LR (MCLR) has been widely investigated in its effects on normal cells, there is little information concerning its effects on cancer cells. In the present study, the SMMC-7721 human liver cancer cell line treated with MCLR was used to investigate the change of PP2A, cytoskeleton rearrangement, phosphorylation levels of PP2A substrates that related with cytoskeleton stability and explored underlying mechanisms. Here, we confirmed that MCLR entered into SMMC-7721 cells, bound to PP2A/C subunit and inhibited the activity of PP2A. The upregulation of phosphorylation of the PP2A/C subunit and PP2A regulation protein α4, as well as the change in the association of PP2A/C with α4, were responsible for the decrease in PP2A activity. Another novel finding is that the rearrangement of filamentous actin and microtubules led by MCLR may attribute to the increased phosphorylation of HSP27, VASP and cofilin due to PP2A inhibition. As a result of weakened interactions with PP2A and alterations in its subcellular localization, Rac1 may contribute to the cytoskeletal rearrangement induced by MCLR in SMMC-7721 cells. The current paper presents the first report demonstrating the characteristic of PP2A in MCLR exposed cancer cells, which were more susceptible to MCLR compared with the normal cell lines we previously found, which may be owing to the absence of some type of compensatory mechanisms. The hyperphosphorylation of cytoskeleton-associated proteins and Rac1 inactivation which were induced by inhibition of PP2A are shown to be involved in cytoskeleton rearrangement.
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Affiliation(s)
- Hao Wang
- Department of Biochemistry, School of Medicine, Zhejiang University, Hangzhou 310058, China
| | - Jinghui Liu
- Department of Biochemistry, School of Medicine, Zhejiang University, Hangzhou 310058, China
| | - Shuyan Lin
- Department of Biochemistry, School of Medicine, Zhejiang University, Hangzhou 310058, China
| | - Beilei Wang
- Department of Biochemistry, School of Medicine, Zhejiang University, Hangzhou 310058, China
| | - Mingluan Xing
- Zhejiang Center for Disease Control and Prevention, Hangzhou 310051, China
| | - Zonglou Guo
- Department of Biosystem Engineering, College of Biosystem Engineering and Food Science, Zhejiang University, Hangzhou 310058, China.
| | - Lihong Xu
- Department of Biochemistry, School of Medicine, Zhejiang University, Hangzhou 310058, China.
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31
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Yang L, Wang X, Yang X. Possible antioxidant mechanism of melanoidins extract from Shanxi aged vinegar in mitophagy-dependent and mitophagy-independent pathways. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2014; 62:8616-8622. [PMID: 25102123 DOI: 10.1021/jf501690e] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Melanoidins are widely reported to have antioxidant activity; however, their mechanism has not been frequently studied. In this study, we found that melanoidins from Shanxi aged vinegar induced mitopahgy, the specific autophagic elimination of mitochondria, as assessed by up-regulation of the autophagy markers LC3-II and Beclin1 as well as degradation of the autophagy substrate p62 and mitochondrial proteins. Melanoidins reduced reactive oxygen species (ROS) in normal human liver cells and mouse livers through a mitophagy-dependent pathway, by the observation that the reducing ROS effect of melanoidins was partially lost when mitophagy was inhibited by chloroquine. Impaired Akt signaling was found in cells treated with melanoidins, which might explain the activation of autophagy induced by melanoidins. These results suggest that in addition to direct free radical scavenging activity, melanoidins decreased ROS levels through mitophagy in which damaged mitochondria, the source of ROS, were degraded.
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Affiliation(s)
- Lei Yang
- College of Life Science, Shanxi University , Taiyuan 030006, China
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32
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Guo B, Huang J, Wu W, Feng D, Wang X, Chen Y, Zhang H. The nascent polypeptide-associated complex is essential for autophagic flux. Autophagy 2014; 10:1738-48. [PMID: 25126725 DOI: 10.4161/auto.29638] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The ribosome-associated nascent polypeptide-associated complex (NAC) is involved in multiple cotranslational processes, including protein transport into the ER and mitochondria, and also acts as a chaperone to assist protein folding. Here we demonstrated that NAC is also essential for autophagic degradation of a variety of protein aggregates in C. elegans. Loss of function of NAC impairs lysosome function, resulting in accumulation of autophagic substrates in enlarged autolysosomes. Knockdown of mammalian NAC also causes accumulation of nondegradative autolysosomes. Our study revealed that NAC plays an evolutionarily conserved role in the autophagy pathway and thus in maintaining protein homeostasis under physiological conditions.
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Affiliation(s)
- Bin Guo
- State Key Laboratory of Biomacromolecules; Institute of Biophysics; Chinese Academy of Sciences; Beijing, China
| | - Jie Huang
- Key Laboratory of Medical Immunology; Ministry of Health; Peking University Health Science Center; Beijing, China; State Key Laboratory of Biomacromolecules; Institute of Biophysics; Chinese Academy of Sciences; Beijing, China
| | - Wenxian Wu
- Institute of Neurology; Key Laboratory of Age-Associated Cardiac-Cerebral Vascular Disease of Guangdong Province; Affiliated Hospital of Guangdong Medical College; Zhanjiang, China
| | - Du Feng
- Institute of Neurology; Key Laboratory of Age-Associated Cardiac-Cerebral Vascular Disease of Guangdong Province; Affiliated Hospital of Guangdong Medical College; Zhanjiang, China
| | - Xiaochen Wang
- National Institute of Biological Sciences; Beijing, China
| | - Yingyu Chen
- Key Laboratory of Medical Immunology; Ministry of Health; Peking University Health Science Center; Beijing, China
| | - Hong Zhang
- State Key Laboratory of Biomacromolecules; Institute of Biophysics; Chinese Academy of Sciences; Beijing, China
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33
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The Ser/Thr phosphatase PP2A regulatory subunit widerborst inhibits notch signaling. PLoS One 2014; 9:e101884. [PMID: 25006677 PMCID: PMC4090204 DOI: 10.1371/journal.pone.0101884] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Accepted: 06/12/2014] [Indexed: 01/23/2023] Open
Abstract
Drosophila Enhancer of split M8, an effector of Notch signaling, is regulated by protein kinase CK2. The phosphatase PP2A is thought to play an opposing (inhibitory) role, but the identity of the regulatory subunit was unknown. The studies described here reveal a role for the PP2A regulatory subunit widerborst (wdb) in three developmental contexts; the bristle, wing and the R8 photoreceptors of the eye. wdb overexpression elicits bristle and wing defects akin to reduced Notch signaling, whereas hypomorphic mutations in this PP2A subunit elicit opposite effects. We have also evaluated wdb functions using mutations in Notch and E(spl) that affect the eye. We find that the eye and R8 defects of the well-known Nspl mutation are enhanced by a hypomorphic allele of wdb, whereas they are strongly rescued by wdb overexpression. Similarly, ectopic wdb rescues the eye and R8 defects of the E(spl)D mutation, which affects the m8 gene. In addition, wdb overexpression also rescues the bristle defects of ectopically expressed M8, or the eye and R8 defects of its CK2 phosphomimetic variant M8-S159D. The latter finding suggests that PP2A may target M8 at highly conserved residues in the vicinity of the CK2 site, whose phosphorylation controls repression of Atonal and the R8 fate. Together, the studies identify PP2A-Wdb as a participant in Notch signaling, and suggest that M8 activity is controlled by phosphorylation and dephosphorylation. The conservation of the phosphorylation sites between Drosophila E(spl) and the HES/HER proteins from mammals, reptiles, amphibians, birds and fish raises the prospect that this mode of regulation is widespread.
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Jin M, Klionsky DJ. Regulation of autophagy: modulation of the size and number of autophagosomes. FEBS Lett 2014; 588:2457-63. [PMID: 24928445 DOI: 10.1016/j.febslet.2014.06.015] [Citation(s) in RCA: 102] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Revised: 06/02/2014] [Accepted: 06/03/2014] [Indexed: 10/25/2022]
Abstract
Autophagy as a conserved degradation and recycling process in eukaryotic cells, occurs constitutively, but is induced by stress. A fine regulation of autophagy in space, time, and intensity is critical for maintaining normal energy homeostasis and metabolism, and to allow for its therapeutic modulation in various autophagy-related human diseases. Autophagy activity is regulated in both transcriptional and post-translational manners. In this review, we summarize the cytosolic regulation of autophagy via its molecular machinery, and nuclear regulation by transcription factors. Specifically, we consider Ume6-ATG8 and Pho23-ATG9 transcriptional regulation in detail, as examples of how nuclear transcription factors and cytosolic machinery cooperate to determine autophagosome size and number, which are the two main mechanistic factors through which autophagy activity is regulated.
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Affiliation(s)
- Meiyan Jin
- Life Sciences Institute, and the Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, United States
| | - Daniel J Klionsky
- Life Sciences Institute, and the Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, United States.
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35
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Lőrincz P, Lakatos Z, Maruzs T, Szatmári Z, Kis V, Sass M. Atg6/UVRAG/Vps34-containing lipid kinase complex is required for receptor downregulation through endolysosomal degradation and epithelial polarity during Drosophila wing development. BIOMED RESEARCH INTERNATIONAL 2014; 2014:851349. [PMID: 25006588 PMCID: PMC4074780 DOI: 10.1155/2014/851349] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Accepted: 04/01/2014] [Indexed: 11/18/2022]
Abstract
Atg6 (Beclin 1 in mammals) is a core component of the Vps34 PI3K (III) complex, which promotes multiple vesicle trafficking pathways. Atg6 and Vps34 form two distinct PI3K (III) complexes in yeast and mammalian cells, either with Atg14 or with UVRAG. The functions of these two complexes are not entirely clear, as both Atg14 and UVRAG have been suggested to regulate both endocytosis and autophagy. In this study, we performed a microscopic analysis of UVRAG, Atg14, or Atg6 loss-of-function cells in the developing Drosophila wing. Both autophagy and endocytosis are seriously impaired and defective endolysosomes accumulate upon loss of Atg6. We show that Atg6 is required for the downregulation of Notch and Wingless signaling pathways; thus it is essential for normal wing development. Moreover, the loss of Atg6 impairs cell polarity. Atg14 depletion results in autophagy defects with no effect on endocytosis or cell polarity, while the silencing of UVRAG phenocopies all but the autophagy defect of Atg6 depleted cells. Thus, our results indicate that the UVRAG-containing PI3K (III) complex is required for receptor downregulation through endolysosomal degradation and for the establishment of proper cell polarity in the developing wing, while the Atg14-containing complex is involved in autophagosome formation.
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Affiliation(s)
- Péter Lőrincz
- Department of Anatomy, Cell and Developmental Biology, Eotvos Lorand University, Budapest 1117, Hungary
| | - Zsolt Lakatos
- Department of Anatomy, Cell and Developmental Biology, Eotvos Lorand University, Budapest 1117, Hungary
| | - Tamás Maruzs
- Department of Anatomy, Cell and Developmental Biology, Eotvos Lorand University, Budapest 1117, Hungary
| | - Zsuzsanna Szatmári
- Department of Anatomy, Cell and Developmental Biology, Eotvos Lorand University, Budapest 1117, Hungary
| | - Viktor Kis
- Department of Anatomy, Cell and Developmental Biology, Eotvos Lorand University, Budapest 1117, Hungary
| | - Miklós Sass
- Department of Anatomy, Cell and Developmental Biology, Eotvos Lorand University, Budapest 1117, Hungary
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36
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Mulakkal NC, Nagy P, Takats S, Tusco R, Juhász G, Nezis IP. Autophagy in Drosophila: from historical studies to current knowledge. BIOMED RESEARCH INTERNATIONAL 2014; 2014:273473. [PMID: 24949430 PMCID: PMC4052151 DOI: 10.1155/2014/273473] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Accepted: 04/17/2014] [Indexed: 12/17/2022]
Abstract
The discovery of evolutionarily conserved Atg genes required for autophagy in yeast truly revolutionized this research field and made it possible to carry out functional studies on model organisms. Insects including Drosophila are classical and still popular models to study autophagy, starting from the 1960s. This review aims to summarize past achievements and our current knowledge about the role and regulation of autophagy in Drosophila, with an outlook to yeast and mammals. The basic mechanisms of autophagy in fruit fly cells appear to be quite similar to other eukaryotes, and the role that this lysosomal self-degradation process plays in Drosophila models of various diseases already made it possible to recognize certain aspects of human pathologies. Future studies in this complete animal hold great promise for the better understanding of such processes and may also help finding new research avenues for the treatment of disorders with misregulated autophagy.
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Affiliation(s)
- Nitha C. Mulakkal
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, UK
| | - Peter Nagy
- Department of Anatomy, Cell and Developmental Biology, Eötvös Loránd University, Budapest H-1117, Hungary
| | - Szabolcs Takats
- Department of Anatomy, Cell and Developmental Biology, Eötvös Loránd University, Budapest H-1117, Hungary
| | - Radu Tusco
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, UK
| | - Gábor Juhász
- Department of Anatomy, Cell and Developmental Biology, Eötvös Loránd University, Budapest H-1117, Hungary
| | - Ioannis P. Nezis
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, UK
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37
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Puustinen P, Rytter A, Mortensen M, Kohonen P, Moreira JM, Jäättelä M. CIP2A oncoprotein controls cell growth and autophagy through mTORC1 activation. ACTA ACUST UNITED AC 2014; 204:713-27. [PMID: 24590173 PMCID: PMC3941044 DOI: 10.1083/jcb.201304012] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
As part of a regulatory loop linking cell metabolism, growth, and proliferation, CIP2A promotes mTORC1-mediated cell growth and autophagy inhibition but is itself down-regulated by autophagy. mTORC1 (mammalian target of rapamycin complex 1) integrates information regarding availability of nutrients and energy to coordinate protein synthesis and autophagy. Using ribonucleic acid interference screens for autophagy-regulating phosphatases in human breast cancer cells, we identify CIP2A (cancerous inhibitor of PP2A [protein phosphatase 2A]) as a key modulator of mTORC1 and autophagy. CIP2A associates with mTORC1 and acts as an allosteric inhibitor of mTORC1-associated PP2A, thereby enhancing mTORC1-dependent growth signaling and inhibiting autophagy. This regulatory circuit is reversed by ubiquitination and p62/SQSTM1-dependent autophagic degradation of CIP2A and subsequent inhibition of mTORC1 activity. Consistent with CIP2A’s reported ability to protect c-Myc against proteasome-mediated degradation, autophagic degradation of CIP2A upon mTORC1 inhibition leads to destabilization of c-Myc. These data characterize CIP2A as a distinct regulator of mTORC1 and reveals mTORC1-dependent control of CIP2A degradation as a mechanism that links mTORC1 activity with c-Myc stability to coordinate cellular metabolism, growth, and proliferation.
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Affiliation(s)
- Pietri Puustinen
- Cell Death and Metabolism, Danish Cancer Society Research Center, 2100 Copenhagen, Denmark
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38
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Hegedűs K, Nagy P, Gáspári Z, Juhász G. The putative HORMA domain protein Atg101 dimerizes and is required for starvation-induced and selective autophagy in Drosophila. BIOMED RESEARCH INTERNATIONAL 2014; 2014:470482. [PMID: 24895579 PMCID: PMC4034400 DOI: 10.1155/2014/470482] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Accepted: 03/11/2014] [Indexed: 12/27/2022]
Abstract
The large-scale turnover of intracellular material including organelles is achieved by autophagy-mediated degradation in lysosomes. Initiation of autophagy is controlled by a protein kinase complex consisting of an Atg1-family kinase, Atg13, FIP200/Atg17, and the metazoan-specific subunit Atg101. Here we show that loss of Atg101 impairs both starvation-induced and basal autophagy in Drosophila. This leads to accumulation of protein aggregates containing the selective autophagy cargo ref(2)P/p62. Mapping experiments suggest that Atg101 binds to the N-terminal HORMA domain of Atg13 and may also interact with two unstructured regions of Atg1. Another HORMA domain-containing protein, Mad2, forms a conformational homodimer. We show that Drosophila Atg101 also dimerizes, and it is predicted to fold into a HORMA domain. Atg101 interacts with ref(2)P as well, similar to Atg13, Atg8a, Atg16, Atg18, Keap1, and RagC, a known regulator of Tor kinase which coordinates cell growth and autophagy. These results raise the possibility that the interactions and dimerization of the putative HORMA domain protein Atg101 play critical roles in starvation-induced autophagy and proteostasis, by promoting the formation of protein aggregate-containing autophagosomes.
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Affiliation(s)
- Krisztina Hegedűs
- Department of Anatomy, Cell and Developmental Biology, Eötvös Loránd University, Budapest 1117, Hungary
| | - Péter Nagy
- Department of Anatomy, Cell and Developmental Biology, Eötvös Loránd University, Budapest 1117, Hungary
| | - Zoltán Gáspári
- Faculty of Information Technology and Bionics, Pázmány Péter Catholic University, Budapest 1083, Hungary
| | - Gábor Juhász
- Department of Anatomy, Cell and Developmental Biology, Eötvös Loránd University, Budapest 1117, Hungary
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39
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Gertner DM, Desai S, Lnenicka GA. Synaptic excitation is regulated by the postsynaptic dSK channel at the Drosophila larval NMJ. J Neurophysiol 2014; 111:2533-43. [PMID: 24671529 DOI: 10.1152/jn.00903.2013] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In the mammalian central nervous system, the postsynaptic small-conductance Ca(2+)-dependent K(+) (SK) channel has been shown to reduce postsynaptic depolarization and limit Ca(2+) influx through N-methyl-d-aspartate receptors. To examine further the role of the postsynaptic SK channel in synaptic transmission, we studied its action at the Drosophila larval neuromuscular junction (NMJ). Repetitive synaptic stimulation produced an increase in postsynaptic membrane conductance leading to depression of excitatory postsynaptic potential amplitude and hyperpolarization of the resting membrane potential (RMP). This reduction in synaptic excitation was due to the postsynaptic Drosophila SK (dSK) channel; synaptic depression, increased membrane conductance and RMP hyperpolarization were reduced in dSK mutants or after expressing a Ca(2+) buffer in the muscle. Ca(2+) entering at the postsynaptic membrane was sufficient to activate dSK channels based upon studies in which the muscle membrane was voltage clamped to prevent opening voltage-dependent Ca(2+) channels. Increasing external Ca(2+) produced an increase in resting membrane conductance and RMP that was not seen in dSK mutants or after adding the glutamate-receptor blocker philanthotoxin. Thus it appeared that dSK channels were also activated by spontaneous transmitter release and played a role in setting membrane conductance and RMP. In mammals, dephosphorylation by protein phosphatase 2A (PP2A) increased the Ca(2+) sensitivity of the SK channel; PP2A appeared to increase the sensitivity of the dSK channel since PP2A inhibitors reduced activation of the dSK channel by evoked synaptic activity or increased external Ca(2+). It is proposed that spontaneous and evoked transmitter release activate the postsynaptic dSK channel to limit synaptic excitation and stabilize synapses.
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Affiliation(s)
- Daniel M Gertner
- Department of Biological Sciences, University at Albany, Albany, New York
| | - Sunil Desai
- Department of Biological Sciences, University at Albany, Albany, New York
| | - Gregory A Lnenicka
- Department of Biological Sciences, University at Albany, Albany, New York
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40
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Nagy P, Kárpáti M, Varga Á, Pircs K, Venkei Z, Takáts S, Varga K, Érdi B, Hegedűs K, Juhász G. Atg17/FIP200 localizes to perilysosomal Ref(2)P aggregates and promotes autophagy by activation of Atg1 in Drosophila. Autophagy 2014; 10:453-67. [PMID: 24419107 PMCID: PMC4077884 DOI: 10.4161/auto.27442] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Revised: 11/26/2013] [Accepted: 12/05/2013] [Indexed: 11/19/2022] Open
Abstract
Phagophore-derived autophagosomes deliver cytoplasmic material to lysosomes for degradation and reuse. Autophagy mediated by the incompletely characterized actions of Atg proteins is involved in numerous physiological and pathological settings including stress resistance, immunity, aging, cancer, and neurodegenerative diseases. Here we characterized Atg17/FIP200, the Drosophila ortholog of mammalian RB1CC1/FIP200, a proposed functional equivalent of yeast Atg17. Atg17 disruption inhibits basal, starvation-induced and developmental autophagy, and interferes with the programmed elimination of larval salivary glands and midgut during metamorphosis. Upon starvation, Atg17-positive structures appear at aggregates of the selective cargo Ref(2)P/p62 near lysosomes. This location may be similar to the perivacuolar PAS (phagophore assembly site) described in yeast. Drosophila Atg17 is a member of the Atg1 kinase complex as in mammals, and we showed that it binds to the other subunits including Atg1, Atg13, and Atg101 (C12orf44 in humans, 9430023L20Rik in mice and RGD1359310 in rats). Atg17 is required for the kinase activity of endogenous Atg1 in vivo, as loss of Atg17 prevents the Atg1-dependent shift of endogenous Atg13 to hyperphosphorylated forms, and also blocks punctate Atg1 localization during starvation. Finally, we found that Atg1 overexpression induces autophagy and reduces cell size in Atg17-null mutant fat body cells, and that overexpression of Atg17 promotes endogenous Atg13 phosphorylation and enhances autophagy in an Atg1-dependent manner in the fat body. We propose a model according to which the relative activity of Atg1, estimated by the ratio of hyper- to hypophosphorylated Atg13, contributes to setting low (basal) vs. high (starvation-induced) autophagy levels in Drosophila.
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Affiliation(s)
| | | | - Ágnes Varga
- Department of Anatomy, Cell and Developmental Biology; Eötvös Loránd University; Budapest, Hungary
| | - Karolina Pircs
- Department of Anatomy, Cell and Developmental Biology; Eötvös Loránd University; Budapest, Hungary
| | | | - Szabolcs Takáts
- Department of Anatomy, Cell and Developmental Biology; Eötvös Loránd University; Budapest, Hungary
| | - Kata Varga
- Department of Anatomy, Cell and Developmental Biology; Eötvös Loránd University; Budapest, Hungary
| | | | - Krisztina Hegedűs
- Department of Anatomy, Cell and Developmental Biology; Eötvös Loránd University; Budapest, Hungary
| | - Gábor Juhász
- Department of Anatomy, Cell and Developmental Biology; Eötvös Loránd University; Budapest, Hungary
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41
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A targeted genetic modifier screen links the SWI2/SNF2 protein domino to growth and autophagy genes in Drosophila melanogaster. G3-GENES GENOMES GENETICS 2013; 3:815-25. [PMID: 23550128 PMCID: PMC3656729 DOI: 10.1534/g3.112.005496] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Targeted genetic studies can facilitate phenotypic analyses and provide important insights into development and other complex processes. The SWI2/SNF2 DNA-dependent ATPase Domino (Dom) of Drosophila melanogaster, a component of the Tip60 acetyltransferase complex, has been associated with a wide spectrum of cellular processes at multiple developmental stages. These include hematopoiesis, cell proliferation, homeotic gene regulation, histone exchange during DNA repair, and Notch signaling. To explore the wider gene network associated with Dom action, we used RNAi directed against domino (dom) to mediate loss-of-function at the wing margin, a tissue that is readily scored for phenotypic changes. Dom RNAi driven through GAL4-UAS elicited dominant wing nicking that responded phenotypically to the dose of dom and other loci known to function with dom. We screened for phenotypic modifiers of this wing phenotype among 2500 transpositions of the EP P element and found both enhancers and suppressors. Several classes of modifier were obtained, including those encoding transcription factors, RNA regulatory proteins, and factors that regulate cell growth, proliferation and autophagy, a lysosomal degradation pathway that affects cell growth under conditions of starvation and stress. Our analysis is consistent with prior studies, suggesting that Dom acts pleiotropically as a positive effector of Notch signaling and a repressor of proliferation. This genetic system should facilitate screens for additional loci associated with Dom function, and complement biochemical approaches to their regulatory activity.
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Wong PM, Puente C, Ganley IG, Jiang X. The ULK1 complex: sensing nutrient signals for autophagy activation. Autophagy 2013; 9:124-37. [PMID: 23295650 PMCID: PMC3552878 DOI: 10.4161/auto.23323] [Citation(s) in RCA: 366] [Impact Index Per Article: 33.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The Atg1/ULK1 complex plays a central role in starvation-induced autophagy, integrating signals from upstream sensors such as MTOR and AMPK and transducing them to the downstream autophagy pathway. Much progress has been made in the last few years in understanding the mechanisms by which the complex is regulated through protein-protein interactions and post-translational modifications, providing insights into how the cell modulates autophagy, particularly in response to nutrient status. However, how the ULK1 complex transduces upstream signals to the downstream central autophagy pathway is still unclear. Although the protein kinase activity of ULK1 is required for its autophagic function, its protein substrate(s) responsible for autophagy activation has not been identified. Furthermore, examples of potential ULK1-independent autophagy have emerged, indicating that under certain specific contexts, the ULK1 complex might be dispensable for autophagy activation. This raises the question of how the autophagic machinery is activated independent of the ULK1 complex and what are the biological functions of such noncanonical autophagy pathways.
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Affiliation(s)
- Pui-Mun Wong
- Cell Biology Program; Memorial Sloan-Kettering Cancer Center; New York, NY USA
| | - Cindy Puente
- Cell Biology Program; Memorial Sloan-Kettering Cancer Center; New York, NY USA
| | - Ian G. Ganley
- MRC Protein Phosphorylation Unit; University of Dundee; Dundee, Scotland UK
| | - Xuejun Jiang
- Cell Biology Program; Memorial Sloan-Kettering Cancer Center; New York, NY USA
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