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Tabata K, Imai K, Fukuda K, Yamamoto K, Kunugi H, Fujita T, Kaminishi T, Tischer C, Neumann B, Reither S, Verissimo F, Pepperkok R, Yoshimori T, Hamasaki M. Palmitoylation of ULK1 by ZDHHC13 plays a crucial role in autophagy. Nat Commun 2024; 15:7194. [PMID: 39169022 DOI: 10.1038/s41467-024-51402-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Accepted: 08/05/2024] [Indexed: 08/23/2024] Open
Abstract
Autophagy is a highly conserved process from yeast to mammals in which intracellular materials are engulfed by a double-membrane organelle called autophagosome and degrading materials by fusing with the lysosome. The process of autophagy is regulated by sequential recruitment and function of autophagy-related (Atg) proteins. Genetic hierarchical analyses show that the ULK1 complex comprised of ULK1-FIP200-ATG13-ATG101 translocating from the cytosol to autophagosome formation sites as a most upstream ATG factor; this translocation is critical in autophagy initiation. However, how this translocation occurs remains unclear. Here, we show that ULK1 is palmitoylated by palmitoyltransferase ZDHHC13 and translocated to the autophagosome formation site upon autophagy induction. We find that the ULK1 palmitoylation is required for autophagy initiation. Moreover, the ULK1 palmitoylated enhances the phosphorylation of ATG14L, which is required for activating PI3-Kinase and producing phosphatidylinositol 3-phosphate, one of the autophagosome membrane's lipids. Our results reveal how the most upstream ULK1 complex translocates to the autophagosome formation sites during autophagy.
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Affiliation(s)
- Keisuke Tabata
- Laboratory of Intracellular Membrane Dynamics, Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
- Department of Genetics, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Kenta Imai
- Laboratory of Intracellular Membrane Dynamics, Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
- Department of Genetics, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Koki Fukuda
- Laboratory of Intracellular Membrane Dynamics, Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
- Department of Genetics, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Kentaro Yamamoto
- Laboratory of Intracellular Membrane Dynamics, Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
- Department of Genetics, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Hayato Kunugi
- Laboratory of Intracellular Membrane Dynamics, Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
- Department of Genetics, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Toshiharu Fujita
- Laboratory of Intracellular Membrane Dynamics, Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
- Department of Genetics, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Tatsuya Kaminishi
- Department of Genetics, Graduate School of Medicine, Osaka University, Osaka, Japan
- Integrated Frontier Research for Medical Science Division, Institute for Open and Transdisciplinary Research Initiatives (OTRI), Osaka University, Osaka, Japan
| | | | - Beate Neumann
- Advanced Light Microscopy Facility, EMBL, Heidelberg, Germany
| | - Sabine Reither
- Advanced Light Microscopy Facility, EMBL, Heidelberg, Germany
| | | | - Rainer Pepperkok
- Advanced Light Microscopy Facility, EMBL, Heidelberg, Germany
- Cell Biology and Biophysics Unit, EMBL, Heidelberg, Germany
| | - Tamotsu Yoshimori
- Laboratory of Intracellular Membrane Dynamics, Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan.
- Department of Genetics, Graduate School of Medicine, Osaka University, Osaka, Japan.
- Integrated Frontier Research for Medical Science Division, Institute for Open and Transdisciplinary Research Initiatives (OTRI), Osaka University, Osaka, Japan.
| | - Maho Hamasaki
- Laboratory of Intracellular Membrane Dynamics, Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan.
- Department of Genetics, Graduate School of Medicine, Osaka University, Osaka, Japan.
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Nguyen AT, Masuda M, Mori Y, Adachi Y, Fukuda T, Furuichi A, Takikawa M, Tsuda Y, Hamada Y, Maruyama Y, Ohminami H, Ohnishi K, Taketani Y. All-trans retinoic acid induces lipophagy by reducing Rubicon in Hepa1c1c7 cells. J Lipid Res 2024; 65:100598. [PMID: 39032560 DOI: 10.1016/j.jlr.2024.100598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2024] [Revised: 07/13/2024] [Accepted: 07/14/2024] [Indexed: 07/23/2024] Open
Abstract
All-trans retinoic acid (atRA), a metabolite of vitamin A, reduces hepatic lipid accumulation in liver steatosis model animals. Lipophagy, a new lipolysis pathway, degrades a lipid droplet (LD) via autophagy in adipose tissue and the liver. We recently found that atRA induces lipophagy in adipocytes. However, it remains unclear whether atRA induces lipophagy in hepatocytes. In this study, we investigated the effects of atRA on lipophagy in Hepa1c1c7 cells and the liver of mice fed a high-fat diet (HFD). First, we confirmed that atRA induced autophagy in Hepa1c1c7 cells by Western blotting and the GFP-LC3-mCherry probe. Next, we evaluated the lipolysis in fatty Hepa1c1c7 cells treated with the knockdown of Atg5, an essential gene in autophagy induction. Atg5-knockdown partly suppressed the atRA-induced lipolysis in fatty Hepa1c1c7 cells. We also found that atRA reduced the protein, but not mRNA, expression of Rubicon, a negative regulator of autophagy, in Hepa1c1c7 cells and the liver of HFD-fed mice. Rubicon-knockdown partly inhibited the atRA-induced lipolysis in fatty Hepa1c1c7 cells. In addition, atRA reduced hepatic Rubicon expression in young mice, but the effect of atRA on it diminished in aged mice. Finally, we investigated the mechanism underlying reduced Rubicon protein expression by atRA in hepatocytes. A protein synthesis inhibitor, but not proteasome or lysosomal inhibitors, significantly blocked the reduction of Rubicon protein expression by atRA in Hepa1c1c7 cells. These results suggest that atRA may promote lipophagy in fatty hepatocytes by reducing hepatic Rubicon expression via inhibiting protein synthesis.
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Affiliation(s)
- Anh The Nguyen
- Department of Clinical Nutrition and Food Management, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushma, Tokushima, Japan
| | - Masashi Masuda
- Department of Clinical Nutrition and Food Management, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushma, Tokushima, Japan.
| | - Yuki Mori
- Department of Clinical Nutrition and Food Management, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushma, Tokushima, Japan
| | - Yuichiro Adachi
- Department of Clinical Nutrition and Food Management, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushma, Tokushima, Japan
| | - Teppei Fukuda
- Department of Clinical Nutrition and Food Management, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushma, Tokushima, Japan
| | - Airi Furuichi
- Department of Clinical Nutrition and Food Management, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushma, Tokushima, Japan
| | - Masaki Takikawa
- Department of Clinical Nutrition and Food Management, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushma, Tokushima, Japan
| | - Yuki Tsuda
- Department of Clinical Nutrition and Food Management, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushma, Tokushima, Japan
| | - Yuki Hamada
- Department of Clinical Nutrition and Food Management, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushma, Tokushima, Japan
| | - Yusuke Maruyama
- Department of Clinical Nutrition and Food Management, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushma, Tokushima, Japan
| | - Hirokazu Ohminami
- Department of Clinical Nutrition and Food Management, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushma, Tokushima, Japan
| | - Kohta Ohnishi
- Department of Clinical Nutrition and Food Management, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushma, Tokushima, Japan
| | - Yutaka Taketani
- Department of Clinical Nutrition and Food Management, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushma, Tokushima, Japan
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Tudorica DA, Basak B, Puerta Cordova AS, Khuu G, Rose K, Lazarou M, Holzbaur EL, Hurley JH. A RAB7A phosphoswitch coordinates Rubicon Homology protein regulation of Parkin-dependent mitophagy. J Cell Biol 2024; 223:e202309015. [PMID: 38728007 PMCID: PMC11090050 DOI: 10.1083/jcb.202309015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 01/12/2024] [Accepted: 04/05/2024] [Indexed: 05/15/2024] Open
Abstract
Activation of PINK1 and Parkin in response to mitochondrial damage initiates a response that includes phosphorylation of RAB7A at Ser72. Rubicon is a RAB7A binding negative regulator of autophagy. The structure of the Rubicon:RAB7A complex suggests that phosphorylation of RAB7A at Ser72 would block Rubicon binding. Indeed, in vitro phosphorylation of RAB7A by TBK1 abrogates Rubicon:RAB7A binding. Pacer, a positive regulator of autophagy, has an RH domain with a basic triad predicted to bind an introduced phosphate. Consistent with this, Pacer-RH binds to phosho-RAB7A but not to unphosphorylated RAB7A. In cells, mitochondrial depolarization reduces Rubicon:RAB7A colocalization whilst recruiting Pacer to phospho-RAB7A-positive puncta. Pacer knockout reduces Parkin mitophagy with little effect on bulk autophagy or Parkin-independent mitophagy. Rescue of Parkin-dependent mitophagy requires the intact pRAB7A phosphate-binding basic triad of Pacer. Together these structural and functional data support a model in which the TBK1-dependent phosphorylation of RAB7A serves as a switch, promoting mitophagy by relieving Rubicon inhibition and favoring Pacer activation.
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Affiliation(s)
- Dan A. Tudorica
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD, USA
- Graduate Group in Biophysics, University of California, Berkeley, Berkeley, CA, USA
- California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, CA, USA
| | - Bishal Basak
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD, USA
- Department of Physiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Alexia S. Puerta Cordova
- California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, CA, USA
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
| | - Grace Khuu
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD, USA
- Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
| | - Kevin Rose
- California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, CA, USA
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
| | - Michael Lazarou
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD, USA
- Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
| | - Erika L.F. Holzbaur
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD, USA
- Department of Physiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - James H. Hurley
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD, USA
- Graduate Group in Biophysics, University of California, Berkeley, Berkeley, CA, USA
- California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, CA, USA
- Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA, USA
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Gambari R, Finotti A. Therapeutic Relevance of Inducing Autophagy in β-Thalassemia. Cells 2024; 13:918. [PMID: 38891049 PMCID: PMC11171814 DOI: 10.3390/cells13110918] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2024] [Revised: 05/09/2024] [Accepted: 05/22/2024] [Indexed: 06/20/2024] Open
Abstract
The β-thalassemias are inherited genetic disorders affecting the hematopoietic system. In β-thalassemias, more than 350 mutations of the adult β-globin gene cause the low or absent production of adult hemoglobin (HbA). A clinical parameter affecting the physiology of erythroid cells is the excess of free α-globin. Possible experimental strategies for a reduction in excess free α-globin chains in β-thalassemia are CRISPR-Cas9-based genome editing of the β-globin gene, forcing "de novo" HbA production and fetal hemoglobin (HbF) induction. In addition, a reduction in excess free α-globin chains in β-thalassemia can be achieved by induction of the autophagic process. This process is regulated by the Unc-51-like kinase 1 (Ulk1) gene. The interplay with the PI3K/Akt/TOR pathway, with the activity of the α-globin stabilizing protein (AHSP) and the involvement of microRNAs in autophagy and Ulk1 gene expression, is presented and discussed in the context of identifying novel biomarkers and potential therapeutic targets for β-thalassemia.
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Affiliation(s)
| | - Alessia Finotti
- Center “Chiara Gemmo and Elio Zago” for the Research on Thalassemia, Department of Life Sciences and Biotechnology, University of Ferrara, 44121 Ferrara, Italy;
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Das BK, Minocha T, Kunika MD, Kannan A, Gao L, Mohan S, Xing W, Varughese KI, Zhao H. Molecular and functional mapping of Plekhm1-Rab7 interaction in osteoclasts. JBMR Plus 2024; 8:ziae034. [PMID: 38586475 PMCID: PMC10994564 DOI: 10.1093/jbmrpl/ziae034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Revised: 02/21/2024] [Accepted: 03/08/2024] [Indexed: 04/09/2024] Open
Abstract
Mutations in PLEKHM1 cause osteopetrosis in humans and rats. The germline and osteoclast conditional deletions of Plekhm1 gene in mice lead to defective osteoclast bone resorption and increased trabecular bone mass without overt abnormalities in other organs. As an adaptor protein, pleckstrin homology and RUN domain containing M1 (PLEKHM1) interacts with the key lysosome regulator small GTPase RAB7 via its C-terminal RUBICON homologous (RH) domain. In this study, we have conducted a structural-functional study of the PLEKHM1 RH domain and RAB7 interaction in osteoclasts in vitro. The single mutations of the key residues in the Plekhm1 RH predicted from the crystal structure of the RUBICON RH domain and RAB7 interface failed to disrupt the Plekhm1-Rab7 binding, lysosome trafficking, and bone resorption. The compound alanine mutations at Y949-R954 and L1011-I1018 regions decreased Plekhm1 protein stability and Rab7-binding, respectively, thereby attenuated lysosome trafficking and bone resorption in osteoclasts. In contrast, the compound alanine mutations at R1060-Q1068 region were dispensable for Rab7-binding and Plekhm1 function in osteoclasts. These results indicate that the regions spanning Y949-R954 and L1011-I1018 of Plekhm1 RH domain are functionally important for Plekhm1 in osteoclasts and offer the therapeutic targets for blocking bone resorption in treatment of osteoporosis and other metabolic bone diseases.
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Affiliation(s)
- Bhaba K Das
- Southern California Institute for Research and Education, VA Long Beach Healthcare System, Long Beach, CA 90822, United States
| | - Tarun Minocha
- Southern California Institute for Research and Education, VA Long Beach Healthcare System, Long Beach, CA 90822, United States
| | - Mikaela D Kunika
- Southern California Institute for Research and Education, VA Long Beach Healthcare System, Long Beach, CA 90822, United States
| | - Aarthi Kannan
- Southern California Institute for Research and Education, VA Long Beach Healthcare System, Long Beach, CA 90822, United States
- Department of Dermatology, University of California-Irvine, Irvine, CA 92697, United States
| | - Ling Gao
- Southern California Institute for Research and Education, VA Long Beach Healthcare System, Long Beach, CA 90822, United States
- Department of Dermatology, University of California-Irvine, Irvine, CA 92697, United States
| | - Subburaman Mohan
- Musculoskeletal Disease Center, VA Loma Linda Healthcare System, Loma Linda, CA 92357, United States
| | - Weirong Xing
- Musculoskeletal Disease Center, VA Loma Linda Healthcare System, Loma Linda, CA 92357, United States
| | - Kottayil I Varughese
- Department of Physiology and Cell Biology, University of Arkansas for Medical Sciences, Little Rock 72205, AR, United States
| | - Haibo Zhao
- Southern California Institute for Research and Education, VA Long Beach Healthcare System, Long Beach, CA 90822, United States
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6
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O'Meara MJ, Rapala JR, Nichols CB, Alexandre AC, Billmyre RB, Steenwyk JL, Alspaugh JA, O'Meara TR. CryptoCEN: A Co-Expression Network for Cryptococcus neoformans reveals novel proteins involved in DNA damage repair. PLoS Genet 2024; 20:e1011158. [PMID: 38359090 PMCID: PMC10901339 DOI: 10.1371/journal.pgen.1011158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Revised: 02/28/2024] [Accepted: 01/30/2024] [Indexed: 02/17/2024] Open
Abstract
Elucidating gene function is a major goal in biology, especially among non-model organisms. However, doing so is complicated by the fact that molecular conservation does not always mirror functional conservation, and that complex relationships among genes are responsible for encoding pathways and higher-order biological processes. Co-expression, a promising approach for predicting gene function, relies on the general principal that genes with similar expression patterns across multiple conditions will likely be involved in the same biological process. For Cryptococcus neoformans, a prevalent human fungal pathogen greatly diverged from model yeasts, approximately 60% of the predicted genes in the genome lack functional annotations. Here, we leveraged a large amount of publicly available transcriptomic data to generate a C. neoformans Co-Expression Network (CryptoCEN), successfully recapitulating known protein networks, predicting gene function, and enabling insights into the principles influencing co-expression. With 100% predictive accuracy, we used CryptoCEN to identify 13 new DNA damage response genes, underscoring the utility of guilt-by-association for determining gene function. Overall, co-expression is a powerful tool for uncovering gene function, and decreases the experimental tests needed to identify functions for currently under-annotated genes.
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Affiliation(s)
- Matthew J O'Meara
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Jackson R Rapala
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Connie B Nichols
- Departments of Medicine and Molecular Genetics/Microbiology; and Cell Biology, Duke University School of Medicine, Durham, North Carolina, United States of America
| | - A Christina Alexandre
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - R Blake Billmyre
- Departments of Pharmaceutical and Biomedical Sciences/Infectious Disease, College of Pharmacy/College of Veterinary Medicine, University of Georgia, Athens, Georgia, United States of America
| | - Jacob L Steenwyk
- Howard Hughes Medical Institute and the Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California, United States of America
| | - J Andrew Alspaugh
- Departments of Medicine and Molecular Genetics/Microbiology; and Cell Biology, Duke University School of Medicine, Durham, North Carolina, United States of America
| | - Teresa R O'Meara
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, Michigan, United States of America
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7
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O’Meara MJ, Rapala JR, Nichols CB, Alexandre C, Billmyre RB, Steenwyk JL, Alspaugh JA, O’Meara TR. CryptoCEN: A Co-Expression Network for Cryptococcus neoformans reveals novel proteins involved in DNA damage repair. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.17.553567. [PMID: 37645941 PMCID: PMC10462067 DOI: 10.1101/2023.08.17.553567] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
Elucidating gene function is a major goal in biology, especially among non-model organisms. However, doing so is complicated by the fact that molecular conservation does not always mirror functional conservation, and that complex relationships among genes are responsible for encoding pathways and higher-order biological processes. Co-expression, a promising approach for predicting gene function, relies on the general principal that genes with similar expression patterns across multiple conditions will likely be involved in the same biological process. For Cryptococcus neoformans, a prevalent human fungal pathogen greatly diverged from model yeasts, approximately 60% of the predicted genes in the genome lack functional annotations. Here, we leveraged a large amount of publicly available transcriptomic data to generate a C. neoformans Co-Expression Network (CryptoCEN), successfully recapitulating known protein networks, predicting gene function, and enabling insights into the principles influencing co-expression. With 100% predictive accuracy, we used CryptoCEN to identify 13 new DNA damage response genes, underscoring the utility of guilt-by-association for determining gene function. Overall, co-expression is a powerful tool for uncovering gene function, and decreases the experimental tests needed to identify functions for currently under-annotated genes.
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Affiliation(s)
- Matthew J. O’Meara
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI, USA
| | - Jackson R. Rapala
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, USA
| | - Connie B. Nichols
- Departments of Medicine and Molecular Genetics/Microbiology; and Cell Biology, Duke University School of Medicine, Durham, North Carolina, USA
| | - Christina Alexandre
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, USA
| | - R. Blake Billmyre
- Departments of Pharmaceutical and Biomedical Sciences/Infectious Disease, College of Pharmacy/College of Veterinary Medicine, University of Georgia, Athens, Georgia, USA
| | - Jacob L Steenwyk
- Howards Hughes Medical Institute and the Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
| | - J. Andrew Alspaugh
- Departments of Medicine and Molecular Genetics/Microbiology; and Cell Biology, Duke University School of Medicine, Durham, North Carolina, USA
| | - Teresa R. O’Meara
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, USA
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8
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Szinyákovics J, Keresztes F, Kiss EA, Falcsik G, Vellai T, Kovács T. Potent New Targets for Autophagy Enhancement to Delay Neuronal Ageing. Cells 2023; 12:1753. [PMID: 37443788 PMCID: PMC10341134 DOI: 10.3390/cells12131753] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Revised: 06/28/2023] [Accepted: 06/28/2023] [Indexed: 07/15/2023] Open
Abstract
Autophagy is a lysosomal-dependent degradation process of eukaryotic cells responsible for breaking down unnecessary and damaged intracellular components. Autophagic activity gradually declines with age due to genetic control, and this change contributes to the accumulation of cellular damage at advanced ages, thereby causing cells to lose their functionality and viability. This could be particularly problematic in post-mitotic cells including neurons, the mass destruction of which leads to various neurodegenerative diseases. Here, we aim to uncover new regulatory points where autophagy could be specifically activated and test these potential drug targets in neurodegenerative disease models of Drosophila melanogaster. One possible way to activate autophagy is by enhancing autophagosome-lysosome fusion that creates the autolysosome in which the enzymatic degradation happens. The HOPS (homotypic fusion and protein sorting) and SNARE (Snap receptor) protein complexes regulate the fusion process. The HOPS complex forms a bridge between the lysosome and autophagosome with the assistance of small GTPase proteins. Thus, small GTPases are essential for autolysosome maturation, and among these proteins, Rab2 (Ras-associated binding 2), Rab7, and Arl8 (Arf-like 8) are required to degrade the autophagic cargo. For our experiments, we used Drosophila melanogaster as a model organism. Nerve-specific small GTPases were silenced and overexpressed. We examined the effects of these genetic interventions on lifespan, climbing ability, and autophagy. Finally, we also studied the activation of small GTPases in a Parkinson's disease model. Our results revealed that GTP-locked, constitutively active Rab2 (Rab2-CA) and Arl8 (Arl8-CA) expression reduces the levels of the autophagic substrate p62/Ref(2)P in neurons, extends lifespan, and improves the climbing ability of animals during ageing. However, Rab7-CA expression dramatically shortens lifespan and inhibits autophagy. Rab2-CA expression also increases lifespan in a Parkinson's disease model fly strain overexpressing human mutant (A53T) α-synuclein protein. Data provided by this study suggests that Rab2 and Arl8 serve as potential targets for autophagy enhancement in the Drosophila nervous system. In the future, it might be interesting to assess the effect of Rab2 and Arl8 coactivation on autophagy, and it would also be worthwhile to validate these findings in a mammalian model and human cell lines. Molecules that specifically inhibit Rab2 or Arl8 serve as potent drug candidates to modulate the activity of the autophagic process in treating neurodegenerative pathologies. In the future, it would be reasonable to investigate which GAP enzyme can inhibit Rab2 or Arl8 specifically, but not affect Rab7, with similar medical purposes.
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Affiliation(s)
- Janka Szinyákovics
- Department of Genetics, Eötvös Loránd University (ELTE), H-1117 Budapest, Hungary
- Doctoral School of Biology, Institute of Biology, ELTE Eötvös Loránd University (ELTE), Pázmány Péter sétány 1/C, H-1117 Budapest, Hungary
- ELKH-ELTE Genetic Research Group, H-1117 Budapest, Hungary
| | - Fanni Keresztes
- Department of Genetics, Eötvös Loránd University (ELTE), H-1117 Budapest, Hungary
- Doctoral School of Biology, Institute of Biology, ELTE Eötvös Loránd University (ELTE), Pázmány Péter sétány 1/C, H-1117 Budapest, Hungary
| | - Eszter Anna Kiss
- Department of Genetics, Eötvös Loránd University (ELTE), H-1117 Budapest, Hungary
| | - Gergő Falcsik
- Department of Genetics, Eötvös Loránd University (ELTE), H-1117 Budapest, Hungary
| | - Tibor Vellai
- Department of Genetics, Eötvös Loránd University (ELTE), H-1117 Budapest, Hungary
- ELKH-ELTE Genetic Research Group, H-1117 Budapest, Hungary
| | - Tibor Kovács
- Department of Genetics, Eötvös Loránd University (ELTE), H-1117 Budapest, Hungary
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9
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Szabó Á, Vincze V, Chhatre AS, Jipa A, Bognár S, Varga KE, Banik P, Harmatos-Ürmösi A, Neukomm LJ, Juhász G. LC3-associated phagocytosis promotes glial degradation of axon debris after injury in Drosophila models. Nat Commun 2023; 14:3077. [PMID: 37248218 DOI: 10.1038/s41467-023-38755-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Accepted: 05/09/2023] [Indexed: 05/31/2023] Open
Abstract
Glial engulfment of neuron-derived debris after trauma, during development, and in neurodegenerative diseases supports nervous system functions. However, mechanisms governing the efficiency of debris degradation in glia have remained largely unexplored. Here we show that LC3-associated phagocytosis (LAP), an engulfment pathway assisted by certain autophagy factors, promotes glial phagosome maturation in the Drosophila wing nerve. A LAP-specific subset of autophagy-related genes is required in glia for axon debris clearance, encoding members of the Atg8a (LC3) conjugation system and the Vps34 lipid kinase complex including UVRAG and Rubicon. Phagosomal Rubicon and Atg16 WD40 domain-dependent conjugation of Atg8a mediate proper breakdown of internalized axon fragments, and Rubicon overexpression in glia accelerates debris elimination. Finally, LAP promotes survival following traumatic brain injury. Our results reveal a role of glial LAP in the clearance of neuronal debris in vivo, with potential implications for the recovery of the injured nervous system.
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Affiliation(s)
- Áron Szabó
- Biological Research Center, Institute of Genetics, Eötvös Loránd Research Network (ELKH), Szeged, H-6726, Hungary.
| | - Virág Vincze
- Biological Research Center, Institute of Genetics, Eötvös Loránd Research Network (ELKH), Szeged, H-6726, Hungary
| | - Aishwarya Sanjay Chhatre
- Biological Research Center, Institute of Genetics, Eötvös Loránd Research Network (ELKH), Szeged, H-6726, Hungary
- Doctoral School of Biology, University of Szeged, Szeged, Hungary
| | - András Jipa
- Biological Research Center, Institute of Genetics, Eötvös Loránd Research Network (ELKH), Szeged, H-6726, Hungary
| | - Sarolta Bognár
- Biological Research Center, Institute of Genetics, Eötvös Loránd Research Network (ELKH), Szeged, H-6726, Hungary
| | - Katalin Eszter Varga
- Biological Research Center, Institute of Genetics, Eötvös Loránd Research Network (ELKH), Szeged, H-6726, Hungary
| | - Poulami Banik
- Biological Research Center, Institute of Genetics, Eötvös Loránd Research Network (ELKH), Szeged, H-6726, Hungary
| | - Adél Harmatos-Ürmösi
- Biological Research Center, Institute of Genetics, Eötvös Loránd Research Network (ELKH), Szeged, H-6726, Hungary
| | - Lukas J Neukomm
- Department of Fundamental Neurosciences, University of Lausanne, CH-1005, Lausanne, Switzerland
| | - Gábor Juhász
- Biological Research Center, Institute of Genetics, Eötvös Loránd Research Network (ELKH), Szeged, H-6726, Hungary.
- Department of Anatomy, Cell and Developmental Biology, Eötvös Loránd University, Budapest, H-1117, Hungary.
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10
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Magné J, Green DR. LC3-associated endocytosis and the functions of Rubicon and ATG16L1. SCIENCE ADVANCES 2022; 8:eabo5600. [PMID: 36288306 PMCID: PMC9604520 DOI: 10.1126/sciadv.abo5600] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
LC3-associated endocytosis (LANDO) is a noncanonical function of the autophagy machinery, in which LC3 (microtubule-associated protein light chain) is conjugated to rab5-positive endosomes, using a portion of the canonical autophagy pathway. LANDO was initially discovered in a murine model of Alzheimer's disease as a critical regulator of amyloid-β receptor recycling in microglial cells, playing a protective role against neuronal loss and memory impairment. Recent evidence suggests an emerging role of LANDO in cytokine receptor signaling and innate immunity. Here, we discuss the regulation of two crucial effectors of LANDO, Rubicon and ATG16L1, and their impact on endocytosis, autophagy, and phagocytosis.
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11
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Teranishi H, Tabata K, Saeki M, Umemoto T, Hatta T, Otomo T, Yamamoto K, Natsume T, Yoshimori T, Hamasaki M. Identification of CUL4A-DDB1-WDFY1 as an E3 ubiquitin ligase complex involved in initiation of lysophagy. Cell Rep 2022; 40:111349. [PMID: 36103833 DOI: 10.1016/j.celrep.2022.111349] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 07/14/2022] [Accepted: 08/22/2022] [Indexed: 01/13/2023] Open
Abstract
Macroautophagy is a bulk degradation system in which double membrane-bound structures called autophagosomes to deliver cytosolic materials to lysosomes. Autophagy promotes cellular homeostasis by selectively recognizing and sequestering specific targets, such as damaged organelles, protein aggregates, and invading bacteria, termed selective autophagy. We previously reported a type of selective autophagy, lysophagy, which helps clear damaged lysosomes. Damaged lysosomes become ubiquitinated and recruit autophagic machinery. Proteomic studies using transfection reagent-coated beads and further evaluations reveal that a CUL4A-DDB1-WDFY1 E3 ubiquitin ligase complex is essential to initiate lysophagy and clear damaged lysosomes. Moreover, we show that LAMP2 is ubiquitinated by the CUL4A E3 ligase complex as a substrate on damaged lysosomes. These results reveal how cells selectively tag damaged lysosomes to initiate autophagy for the clearance of lysosomes.
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Affiliation(s)
- Hirofumi Teranishi
- JT Pharmaceutical Frontier Research Laboratory, Yokohama 236-0004, Japan
| | - Keisuke Tabata
- Laboratory of Intracellular Membrane Dynamics, Graduate School of Frontier Biosciences Osaka University, Osaka 565-0871, Japan; Department of Genetics, Graduate School of Medicine Osaka University, Osaka 565-0871, Japan
| | - Marika Saeki
- Laboratory of Intracellular Membrane Dynamics, Graduate School of Frontier Biosciences Osaka University, Osaka 565-0871, Japan
| | - Tetsuo Umemoto
- Laboratory of Intracellular Membrane Dynamics, Graduate School of Frontier Biosciences Osaka University, Osaka 565-0871, Japan
| | - Tomohisa Hatta
- Molecular Profiling Research Center for Drug Discovery, AIST, Tokyo 135-0064, Japan
| | - Takanobu Otomo
- Department of Genetics, Graduate School of Medicine Osaka University, Osaka 565-0871, Japan
| | - Kentaro Yamamoto
- Laboratory of Intracellular Membrane Dynamics, Graduate School of Frontier Biosciences Osaka University, Osaka 565-0871, Japan
| | - Toru Natsume
- Molecular Profiling Research Center for Drug Discovery, AIST, Tokyo 135-0064, Japan
| | - Tamotsu Yoshimori
- Laboratory of Intracellular Membrane Dynamics, Graduate School of Frontier Biosciences Osaka University, Osaka 565-0871, Japan; Department of Genetics, Graduate School of Medicine Osaka University, Osaka 565-0871, Japan; Integrated Frontier Research for Medical Science Division, Institute for Open and Transdisciplinary Research Initiatives (OTRI), Osaka University, Osaka 565-0871, Japan.
| | - Maho Hamasaki
- Laboratory of Intracellular Membrane Dynamics, Graduate School of Frontier Biosciences Osaka University, Osaka 565-0871, Japan; Department of Genetics, Graduate School of Medicine Osaka University, Osaka 565-0871, Japan.
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12
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Minami S, Nakamura S, Yoshimori T. Rubicon in Metabolic Diseases and Ageing. Front Cell Dev Biol 2022; 9:816829. [PMID: 35083223 PMCID: PMC8784836 DOI: 10.3389/fcell.2021.816829] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Accepted: 12/15/2021] [Indexed: 12/20/2022] Open
Abstract
Autophagy is a conserved cellular degradation system that maintains intracellular homeostasis. Cytoplasmic components are engulfed into double-membrane vesicles called autophagosomes, which fuse with lysosomes, and resulting in the degradation of sequestered materials. Recently, a close association between autophagy and the pathogenesis of metabolic diseases and ageing has become apparent: autophagy is dysregulated during metabolic diseases and ageing; dysregulation of autophagy is intimately associated with the pathophysiology. Rubicon (Run domain Beclin-1 interacting and cysteine-rich containing protein) has been identified as a Beclin-1 associated protein. Notably, Rubicon is one of few negative regulators of autophagy whereas many autophagy-related genes are positive regulators of autophagy. Rubicon also has autophagy-independent functions including phagocytosis and endocytosis. In this mini-review, we focus on the various roles of Rubicon in different organs in the settings of metabolic diseases and ageing, and discuss its potential role as a promising therapeutic target.
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Affiliation(s)
- Satoshi Minami
- Department of Genetics, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Shuhei Nakamura
- Department of Genetics, Graduate School of Medicine, Osaka University, Suita, Japan.,Department of Intracellular Membrane Dynamics, Graduate School of Frontier Biosciences, Osaka University, Suita, Japan.,Institute for Advanced Co-Creation Studies, Osaka University, Suita, Japan
| | - Tamotsu Yoshimori
- Department of Genetics, Graduate School of Medicine, Osaka University, Suita, Japan.,Department of Intracellular Membrane Dynamics, Graduate School of Frontier Biosciences, Osaka University, Suita, Japan.,Integrated Frontier Research for Medical Science Division, Institute for Open and Transdisciplinary Research Initiatives, Osaka University, Suita, Japan
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13
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Sabarwal A, Wedel J, Liu K, Zurakowski D, Chakraborty S, Flynn E, Briscoe DM, Balan M, Pal S. A Combination therapy using an mTOR inhibitor and Honokiol effectively induces autophagy through the modulation of AXL and Rubicon in renal cancer cells and restricts renal tumor growth following organ transplantation. Carcinogenesis 2021; 43:360-370. [PMID: 34965300 PMCID: PMC9118982 DOI: 10.1093/carcin/bgab126] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 12/17/2021] [Accepted: 12/28/2021] [Indexed: 12/31/2022] Open
Abstract
Development of cancer, including renal cancer, is a major problem in immunosuppressed patients. The mTOR inhibitor Rapamycin (RAPA) is used as an immunosuppressive agent in patients with organ transplants and other immunological disorders; and it also has antitumorigenic potential. However, long-term use of RAPA causes reactivation of Akt, and ultimately leads to enhanced tumor growth. Honokiol (HNK) is a natural compound, which possesses both anti-inflammatory and antitumorigenic properties. In this study, we investigated the effect of a novel combination therapy using RAPA + HNK on allograft survival and post-transplantation renal tumor growth. We observed that it effectively modulated the expression of some key regulatory molecules (like Carabin, an endogenous Ras inhibitor; and Rubicon, a negative regulator of autophagy) that play important roles in tumor cell growth and survival. This combination induced toxic autophagy and apoptosis to promote cancer cell death; and was associated with a reduced expression of the tumor-promoting receptor tyrosine kinase AXL. Finally, we utilized a novel murine model to examine the effect of RAPA + HNK on post-transplantation renal tumor growth. The combination treatment prolonged the allograft survival and significantly inhibited post-transplantation tumor growth. It was associated with reduced tumor expression of Rubicon and the cytoprotective/antioxidant heme oxygenase-1 to overcome therapeutic resistance. It also downregulated the coinhibitory programmed death-1 ligand, which plays major role(s) in the immune escape of tumor cells. Together, this combination treatment has a great potential to restrict renal tumor growth in transplant recipients as well as other immunosuppressed patients.
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Affiliation(s)
- Akash Sabarwal
- Division of Nephrology, Boston Children’s Hospital, Boston, MA 02115, USA,Harvard Medical School, Boston, MA 02115, USA
| | - Johannes Wedel
- Division of Nephrology, Boston Children’s Hospital, Boston, MA 02115, USA,Harvard Medical School, Boston, MA 02115, USA
| | - Kaifeng Liu
- Division of Nephrology, Boston Children’s Hospital, Boston, MA 02115, USA,Harvard Medical School, Boston, MA 02115, USA
| | - David Zurakowski
- Division of Nephrology, Boston Children’s Hospital, Boston, MA 02115, USA,Harvard Medical School, Boston, MA 02115, USA
| | - Samik Chakraborty
- Division of Nephrology, Boston Children’s Hospital, Boston, MA 02115, USA,Harvard Medical School, Boston, MA 02115, USA
| | - Evelyn Flynn
- Division of Nephrology, Boston Children’s Hospital, Boston, MA 02115, USA,Harvard Medical School, Boston, MA 02115, USA
| | - David M Briscoe
- Division of Nephrology, Boston Children’s Hospital, Boston, MA 02115, USA,Harvard Medical School, Boston, MA 02115, USA,Transplant Research Program, Boston Children’s Hospital, Boston, MA 02115, USA
| | - Murugabaskar Balan
- Division of Nephrology, Boston Children’s Hospital, Boston, MA 02115, USA,Harvard Medical School, Boston, MA 02115, USA
| | - Soumitro Pal
- Division of Nephrology, Boston Children’s Hospital, Boston, MA 02115, USA,Harvard Medical School, Boston, MA 02115, USA,To whom correspondence should be addressed. Division of Nephrology, Boston Children’s Hospital, 300 Longwood Ave, Boston, MA 02115, USA. Tel: +1 617 919 2989; Fax: +1 617 730 0365;
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14
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Ohashi Y. Activation Mechanisms of the VPS34 Complexes. Cells 2021; 10:cells10113124. [PMID: 34831348 PMCID: PMC8624279 DOI: 10.3390/cells10113124] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Revised: 11/09/2021] [Accepted: 11/09/2021] [Indexed: 01/18/2023] Open
Abstract
Phosphatidylinositol-3-phosphate (PtdIns(3)P) is essential for cell survival, and its intracellular synthesis is spatially and temporally regulated. It has major roles in two distinctive cellular pathways, namely, the autophagy and endocytic pathways. PtdIns(3)P is synthesized from phosphatidylinositol (PtdIns) by PIK3C3C/VPS34 in mammals or Vps34 in yeast. Pathway-specific VPS34/Vps34 activity is the consequence of the enzyme being incorporated into two mutually exclusive complexes: complex I for autophagy, composed of VPS34/Vps34-Vps15/Vps15-Beclin 1/Vps30-ATG14L/Atg14 (mammals/yeast), and complex II for endocytic pathways, in which ATG14L/Atg14 is replaced with UVRAG/Vps38 (mammals/yeast). Because of its involvement in autophagy, defects in which are closely associated with human diseases such as cancer and neurodegenerative diseases, developing highly selective drugs that target specific VPS34/Vps34 complexes is an essential goal in the autophagy field. Recent studies on the activation mechanisms of VPS34/Vps34 complexes have revealed that a variety of factors, including conformational changes, lipid physicochemical parameters, upstream regulators, and downstream effectors, greatly influence the activity of these complexes. This review summarizes and highlights each of these influences as well as clarifying key questions remaining in the field and outlining future perspectives.
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Affiliation(s)
- Yohei Ohashi
- MRC Laboratory of Molecular Biology, Protein and Nucleic Acid Chemistry Division, Francis Crick Avenue, Cambridge CB2 0QH, UK
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15
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Structural basis of human PDZD8-Rab7 interaction for the ER-late endosome tethering. Sci Rep 2021; 11:18859. [PMID: 34552186 PMCID: PMC8458453 DOI: 10.1038/s41598-021-98419-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Accepted: 08/31/2021] [Indexed: 02/02/2023] Open
Abstract
The membrane contact sites (MCSs) between the ER and late endosomes (LEs) are essential for the regulation of endosomal protein sorting, dynamics, and motility. PDZD8 is an ER transmembrane protein containing a Synaptotagmin-like Mitochondrial lipid-binding Proteins (SMP) domain. PDZD8 tethers the ER to late endosomes and lysosomes by associating its C-terminal coiled-coil (CC) with the LE Rab7. To identify the structural determinants for the PDZD8–Rab7 interaction, we determined the crystal structure of the human PDZD8 CC domain in complex with the GTP-bound form of Rab7. The PDZD8 CC contains one short helix and the two helices forming an antiparallel coiled-coil. Two Rab7 molecules bind to the opposite sides of the PDZD8 CC in a 2:1 ratio. The switch I/II and interswitch regions of the GTP-loaded Rab7 form the binding interfaces, which correlates with the GTP-dependent interaction of PDZD8 and Rab7. Analysis of the protein interaction by isothermal titration calorimetry confirms that two Rab7 molecules bind the PDZD8 CC in a GTP-dependent manner. The structural model of the PDZD8 CC–Rab7 complex correlates with the recruitment of PDZD8 at the LE–ER interface and its role in lipid transport and regulation.
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16
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Yin C, Heit B. Cellular Responses to the Efferocytosis of Apoptotic Cells. Front Immunol 2021; 12:631714. [PMID: 33959122 PMCID: PMC8093429 DOI: 10.3389/fimmu.2021.631714] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Accepted: 03/29/2021] [Indexed: 12/17/2022] Open
Abstract
The rapid and efficient phagocytic clearance of apoptotic cells, termed efferocytosis, is a critical mechanism in the maintenance of tissue homeostasis. Removal of apoptotic cells through efferocytosis prevents secondary necrosis and the resultant inflammation caused by the release of intracellular contents. The importance of efferocytosis in homeostasis is underscored by the large number of inflammatory and autoimmune disorders, including atherosclerosis and systemic lupus erythematosus, that are characterized by defective apoptotic cell clearance. Although mechanistically similar to the phagocytic clearance of pathogens, efferocytosis differs from phagocytosis in that it is immunologically silent and induces a tissue repair response. Efferocytes face unique challenges resulting from the internalization of apoptotic cells, including degradation of the apoptotic cell, dealing with the extra metabolic load imposed by the processing of apoptotic cell contents, and the coordination of an anti-inflammatory, pro-tissue repair response. This review will discuss recent advances in our understanding of the cellular response to apoptotic cell uptake, including trafficking of apoptotic cell cargo and antigen presentation, signaling and transcriptional events initiated by efferocytosis, the coordination of an anti-inflammatory response and tissue repair, unique cellular metabolic responses and the role of efferocytosis in host defense. A better understanding of how efferocytic cells respond to apoptotic cell uptake will be critical in unraveling the complex connections between apoptotic cell removal and inflammation resolution and maintenance of tissue homeostasis.
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Affiliation(s)
- Charles Yin
- Department of Microbiology and Immunology, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
- Center for Human Immunology, Western University, London, ON, Canada
| | - Bryan Heit
- Department of Microbiology and Immunology, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
- Center for Human Immunology, Western University, London, ON, Canada
- Robarts Research Institute, London, ON, Canada
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17
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Bhati KK, Luong AM, Batoko H. VPS34 Complexes in Plants: Untangled Enough? TRENDS IN PLANT SCIENCE 2021; 26:303-305. [PMID: 33602624 DOI: 10.1016/j.tplants.2021.02.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 01/29/2021] [Accepted: 02/02/2021] [Indexed: 05/11/2023]
Abstract
Phosphatidylinositol-3-phosphate (PI3P) is essential for endocytosis and autophagy. VPS38 (endocytosis) and ATG14 (autophagy) are required for localized biosynthesis of PI3P. Liu et al. have shown that mutant arabidopsis (Arabidopsis thaliana) lacking both proteins are viable and synthesize PI3P, suggesting that the enzymatic complex VPS34 can function in absence of these regulatory subunits.
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Affiliation(s)
- Kaushal Kumar Bhati
- Louvain Institute of Biomolecular Science and Technology, University of Louvain, Louvain-la-Neuve, Belgium
| | - Ai My Luong
- Louvain Institute of Biomolecular Science and Technology, University of Louvain, Louvain-la-Neuve, Belgium
| | - Henri Batoko
- Louvain Institute of Biomolecular Science and Technology, University of Louvain, Louvain-la-Neuve, Belgium.
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18
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Nah J, Zablocki D, Sadoshima J. The roles of the inhibitory autophagy regulator Rubicon in the heart: A new therapeutic target to prevent cardiac cell death. Exp Mol Med 2021; 53:528-536. [PMID: 33854187 PMCID: PMC8102471 DOI: 10.1038/s12276-021-00600-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 03/03/2021] [Accepted: 03/08/2021] [Indexed: 01/30/2023] Open
Abstract
Autophagy contributes to the maintenance of cardiac homeostasis. The level of autophagy is dynamically altered in heart disease. Although autophagy is a promising therapeutic target, only a few selective autophagy activator candidates have been reported thus far. Rubicon is one of the few endogenous negative regulators of autophagy and a potential target for autophagy-inducing therapeutics. Rubicon was initially identified as a component of the Class III PI3K complex, and it has multiple functions, not only in canonical autophagy but also in endosomal trafficking and inflammatory responses. This review summarizes the molecular action of Rubicon in canonical and noncanonical autophagy. We discuss the roles of Rubicon in cardiac stress and the therapeutic potential of Rubicon in cardiac diseases through its modulation of autophagy.
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Affiliation(s)
- Jihoon Nah
- Department of Cell Biology and Molecular Medicine, Cardiovascular Research Institute, Rutgers New Jersey Medical School, Newark, NJ, USA.
| | - Daniela Zablocki
- Department of Cell Biology and Molecular Medicine, Cardiovascular Research Institute, Rutgers New Jersey Medical School, Newark, NJ, USA
| | - Junichi Sadoshima
- Department of Cell Biology and Molecular Medicine, Cardiovascular Research Institute, Rutgers New Jersey Medical School, Newark, NJ, USA.
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19
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Xiao M, Benoit A, Hasmim M, Duhem C, Vogin G, Berchem G, Noman MZ, Janji B. Targeting Cytoprotective Autophagy to Enhance Anticancer Therapies. Front Oncol 2021; 11:626309. [PMID: 33718194 PMCID: PMC7951055 DOI: 10.3389/fonc.2021.626309] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Accepted: 01/15/2021] [Indexed: 12/21/2022] Open
Abstract
Autophagy is a highly regulated multi-step process that occurs at the basal level in almost all cells. Although the deregulation of the autophagy process has been described in several pathologies, the role of autophagy in cancer as a cytoprotective mechanism is currently well established and supported by experimental and clinical evidence. Our understanding of the molecular mechanism of the autophagy process has largely contributed to defining how we can harness this process to improve the benefit of cancer therapies. While the role of autophagy in tumor resistance to chemotherapy is extensively documented, emerging data point toward autophagy as a mechanism of cancer resistance to radiotherapy, targeted therapy, and immunotherapy. Therefore, manipulating autophagy has emerged as a promising strategy to overcome tumor resistance to various anti-cancer therapies, and autophagy modulators are currently evaluated in combination therapies in several clinical trials. In this review, we will summarize our current knowledge of the impact of genetically and pharmacologically modulating autophagy genes and proteins, involved in the different steps of the autophagy process, on the therapeutic benefit of various cancer therapies. We will also briefly discuss the challenges and limitations to developing potent and selective autophagy inhibitors that could be used in ongoing clinical trials.
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Affiliation(s)
- Malina Xiao
- Tumor Immunotherapy and Microenvironment (TIME) Group, Department of Oncology, Luxembourg Institute of Health (LIH), Luxembourg City, Luxembourg
| | - Alice Benoit
- Tumor Immunotherapy and Microenvironment (TIME) Group, Department of Oncology, Luxembourg Institute of Health (LIH), Luxembourg City, Luxembourg
| | - Meriem Hasmim
- Tumor Immunotherapy and Microenvironment (TIME) Group, Department of Oncology, Luxembourg Institute of Health (LIH), Luxembourg City, Luxembourg
| | - Caroline Duhem
- Department of Hemato-oncology, Centre Hospitalier du Luxembourg, Luxembourg City, Luxembourg
| | - Guillaume Vogin
- Université de Lorraine - UMR 7365, Ingénierie Moléculaire et Physiopathologie Articulaire (IMoPA), Vandoeuvre-lès-Nancy, France.,Centre François Baclesse, Esch-sur-Alzette, Luxembourg
| | - Guy Berchem
- Tumor Immunotherapy and Microenvironment (TIME) Group, Department of Oncology, Luxembourg Institute of Health (LIH), Luxembourg City, Luxembourg.,Department of Hemato-oncology, Centre Hospitalier du Luxembourg, Luxembourg City, Luxembourg
| | - Muhammad Zaeem Noman
- Tumor Immunotherapy and Microenvironment (TIME) Group, Department of Oncology, Luxembourg Institute of Health (LIH), Luxembourg City, Luxembourg
| | - Bassam Janji
- Tumor Immunotherapy and Microenvironment (TIME) Group, Department of Oncology, Luxembourg Institute of Health (LIH), Luxembourg City, Luxembourg
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20
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Lim J, Murthy A. Targeting Autophagy to Treat Cancer: Challenges and Opportunities. Front Pharmacol 2020; 11:590344. [PMID: 33381037 PMCID: PMC7768823 DOI: 10.3389/fphar.2020.590344] [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: 08/01/2020] [Accepted: 10/09/2020] [Indexed: 12/12/2022] Open
Abstract
Autophagy is a catabolic process that targets its cargo for lysosomal degradation. In addition to its function in maintaining tissue homeostasis, autophagy is recognized to play a context-dependent role in cancer. Autophagy may inhibit tumor initiation under specific contexts; however, a growing body of evidence supports a pro-tumorigenic role of this pathway in established disease. In this setting, autophagy drives treatment resistance, metabolic changes, and immunosuppression both in a tumor-intrinsic and extrinsic manner. This observation has prompted renewed interest in targeting autophagy for cancer therapy. Novel genetic models have proven especially insightful, revealing unique and overlapping roles of individual autophagy-related genes in tumor progression. Despite identification of pharmacologically actionable nodes in the pathway, fundamental challenges still exist for successful therapeutic inhibition of autophagy. Here we summarize the current understanding of autophagy as a driver of resistance against targeted and immuno-therapies and highlight knowledge gaps that, if addressed, may provide meaningful advances in the treatment of cancer.
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Affiliation(s)
| | - Aditya Murthy
- Department of Cancer Immunology, Genentech, Inc., South San Francisco, CA, United States
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21
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Farrell DP, Anishchenko I, Shakeel S, Lauko A, Passmore LA, Baker D, DiMaio F. Deep learning enables the atomic structure determination of the Fanconi Anemia core complex from cryoEM. IUCRJ 2020; 7:881-892. [PMID: 32939280 PMCID: PMC7467173 DOI: 10.1107/s2052252520009306] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Accepted: 07/07/2020] [Indexed: 06/11/2023]
Abstract
Cryo-electron microscopy of protein complexes often leads to moderate resolution maps (4-8 Å), with visible secondary-structure elements but poorly resolved loops, making model building challenging. In the absence of high-resolution structures of homologues, only coarse-grained structural features are typically inferred from these maps, and it is often impossible to assign specific regions of density to individual protein subunits. This paper describes a new method for overcoming these difficulties that integrates predicted residue distance distributions from a deep-learned convolutional neural network, computational protein folding using Rosetta, and automated EM-map-guided complex assembly. We apply this method to a 4.6 Å resolution cryoEM map of Fanconi Anemia core complex (FAcc), an E3 ubiquitin ligase required for DNA interstrand crosslink repair, which was previously challenging to interpret as it comprises 6557 residues, only 1897 of which are covered by homology models. In the published model built from this map, only 387 residues could be assigned to the specific subunits with confidence. By building and placing into density 42 deep-learning-guided models containing 4795 residues not included in the previously published structure, we are able to determine an almost-complete atomic model of FAcc, in which 5182 of the 6557 residues were placed. The resulting model is consistent with previously published biochemical data, and facilitates interpretation of disease-related mutational data. We anticipate that our approach will be broadly useful for cryoEM structure determination of large complexes containing many subunits for which there are no homologues of known structure.
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Affiliation(s)
- Daniel P. Farrell
- Department of Biochemistry, University of Washington, Seattle, WA 98105, USA
- Institute for Protein Design, University of Washington, Seattle, WA 98105, USA
| | - Ivan Anishchenko
- Department of Biochemistry, University of Washington, Seattle, WA 98105, USA
- Institute for Protein Design, University of Washington, Seattle, WA 98105, USA
| | - Shabih Shakeel
- MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Anna Lauko
- Department of Biochemistry, University of Washington, Seattle, WA 98105, USA
| | | | - David Baker
- Department of Biochemistry, University of Washington, Seattle, WA 98105, USA
- Institute for Protein Design, University of Washington, Seattle, WA 98105, USA
| | - Frank DiMaio
- Department of Biochemistry, University of Washington, Seattle, WA 98105, USA
- Institute for Protein Design, University of Washington, Seattle, WA 98105, USA
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