1
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Qian W, Lu J, Gao C, Liu Q, Yao W, Wang T, Wang X, Wang Z. Isobavachalcone exhibits antifungal and antibiofilm effects against C. albicans by disrupting cell wall/membrane integrity and inducing apoptosis and autophagy. Front Cell Infect Microbiol 2024; 14:1336773. [PMID: 38322671 PMCID: PMC10845358 DOI: 10.3389/fcimb.2024.1336773] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2023] [Accepted: 01/03/2024] [Indexed: 02/08/2024] Open
Abstract
Isobavachalcone (IBC) is a natural flavonoid with multiple pharmacological properties. This study aimed to evaluate the efficacy of IBC against planktonic growth and biofilms of Candida albicans (C. albicans) and the mechanisms underlying its antifungal action. The cell membrane integrity, cell metabolic viability, and cell morphology of C. albicans treated with IBC were evaluated using CLSM and FESEM analyses. Crystal violet staining, CLSM, and FESEM were used to assess the inhibition of biofilm formation, as well as dispersal and killing effects of IBC on mature biofilms. RNA-seq combined with apoptosis and autophagy assays was used to examine the mechanisms underlying the antifungal action of IBC. IBC exhibited excellent antifungal activity with 8 μg/mL of MIC for C. albicans. IBC disrupted the cell membrane integrity, and inhibited biofilm formation. IBC dispersed mature biofilms and damaged biofilm cells of C. albicans at 32 μg/mL. Moreover, IBC induced apoptosis and autophagy-associated cell death of C. albicans. The RNA-seq analysis revealed upregulation or downregulation of key genes involved in cell wall synthesis (Wsc1 and Fks1), ergosterol biosynthesis (Erg3, and Erg11), apoptisis (Hsp90 and Aif1), as well as autophagy pathways (Atg8, Atg13, and Atg17), and so forth, in response to IBC, as evidenced by the experiment-based phenotypic analysis. These results suggest that IBC inhibits C. albicans growth by disrupting the cell wall/membrane, caused by the altered expression of genes associated with β-1,3-glucan and ergosterol biosynthesis. IBC induces apoptosis and autophagy-associated cell death by upregulating the expression of Hsp90, and altering autophagy-related genes involved in the formation of the Atg1 complex and the pre-autophagosomal structure. Together, our findings provide important insights into the potential multifunctional mechanism of action of IBC.
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Affiliation(s)
- Weidong Qian
- School of Biological and Pharmaceutical Engineering, Shaanxi University of Science and Technology, Xi’an, China
| | - Jiaxing Lu
- School of Biological and Pharmaceutical Engineering, Shaanxi University of Science and Technology, Xi’an, China
| | - Chang Gao
- School of Biological and Pharmaceutical Engineering, Shaanxi University of Science and Technology, Xi’an, China
| | - Qiming Liu
- School of Biological and Pharmaceutical Engineering, Shaanxi University of Science and Technology, Xi’an, China
| | - Wendi Yao
- Department of Urology, Henan Provincial People’s Hospital, Zhengzhou University People’s Hospital, Zhengzhou, China
| | - Ting Wang
- School of Biological and Pharmaceutical Engineering, Shaanxi University of Science and Technology, Xi’an, China
| | - Xiaobin Wang
- Department of Urology, Southern University of Science and Technology Hospital, Shenzhen, China
| | - Zhifeng Wang
- Department of Urology, Henan Provincial People’s Hospital, Zhengzhou University People’s Hospital, Zhengzhou, China
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2
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Wójcik-Mieszawska S, Lewtak K, Skwarek E, Dębowski D, Gitlin-Domagalska A, Nowak J, Wydrych J, Pawelec J, Fiołka MJ. Autophagy of Candida albicans cells after the action of earthworm Venetin-1 nanoparticle with protease inhibitor activity. Sci Rep 2023; 13:14228. [PMID: 37648723 PMCID: PMC10468520 DOI: 10.1038/s41598-023-41281-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Accepted: 08/24/2023] [Indexed: 09/01/2023] Open
Abstract
The present studies show the effect of the Venetin-1 protein-polysaccharide complex obtained from the coelomic fluid of the earthworm Dendrobaena veneta on Candida albicans cells. They are a continuation of research on the mechanisms of action, cellular targets, and modes of cell death. After the action of Venetin-1, a reduced survival rate of the yeast cells was noted. The cells were observed to be enlarged compared to the controls and deformed. In addition, an increase in the number of cells with clearly enlarged vacuoles was noted. The detected autophagy process was confirmed using differential interference contrast, fluorescence microscopy, and transmission electron microscopy. Autophagic vesicles were best visible after incubation of fungus cells with the Venetin-1 complex at a concentration of 50 and 100 µg mL-1. The changes in the vacuoles were accompanied by changes in the size of mitochondria, which is probably related to the previously documented oxidative stress. The aggregation properties of Venetin-1 were characterized. Based on the results of the zeta potential at the Venetin-1/KCl interface, the pHiep = 4 point was determined, i.e. the zeta potential becomes positive above pH = 4 and is negative below this value, which may affect the electrostatic interactions with other particles surrounding Venetin-1.
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Affiliation(s)
- Sylwia Wójcik-Mieszawska
- Department of Immunobiology, Institute of Biological Sciences, Faculty of Biology and Biotechnology, Maria Curie-Skłodowska University, Lublin, Poland
| | - Kinga Lewtak
- Department of Cell Biology, Institute of Biological Sciences, Faculty of Biology and Biotechnology, Maria Curie-Skłodowska University, Lublin, Poland.
| | - Ewa Skwarek
- Department of Radiochemistry and Environmental Chemistry, Institute of Chemical Sciences, Faculty of Chemistry, Maria Curie-Skłodowska University, Lublin, Poland
| | - Dawid Dębowski
- Department of Molecular Biochemistry, Faculty of Chemistry, University of Gdańsk, Gdańsk, Poland
| | - Agata Gitlin-Domagalska
- Department of Molecular Biochemistry, Faculty of Chemistry, University of Gdańsk, Gdańsk, Poland
| | - Jakub Nowak
- Malopolska Centre of Biotechnology, Jagiellonian University, Kraków, Poland
| | - Jerzy Wydrych
- Department of Functional Anatomy and Cytobiology, Institute of Biological Sciences, Maria Curie-Skłodowska University, Lublin, Poland
| | - Jarosław Pawelec
- Department of Functional Anatomy and Cytobiology, Institute of Biological Sciences, Maria Curie-Skłodowska University, Lublin, Poland
| | - Marta J Fiołka
- Department of Immunobiology, Institute of Biological Sciences, Faculty of Biology and Biotechnology, Maria Curie-Skłodowska University, Lublin, Poland.
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3
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Liu Y, Zhu M, Wang W, Li X, Bai N, Xie M, Yang J. AoMae1 Regulates Hyphal Fusion, Lipid Droplet Accumulation, Conidiation, and Trap Formation in Arthrobotrys oligospora. J Fungi (Basel) 2023; 9:jof9040496. [PMID: 37108952 PMCID: PMC10146936 DOI: 10.3390/jof9040496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 04/19/2023] [Accepted: 04/19/2023] [Indexed: 04/29/2023] Open
Abstract
Malate dehydrogenase (MDH) is a key enzyme in the tricarboxylic acid (TCA) cycle and is essential for energy balance, growth, and tolerance to cold and salt stresses in plants. However, the role of MDH in filamentous fungi is still largely unknown. In this study, we characterized an ortholog of MDH (AoMae1) in a representative nematode-trapping (NT) fungus Arthrobotrys oligospora via gene disruption, phenotypic analysis, and nontargeted metabolomics. We found that the loss of Aomae1 led to a weakening of MDH activity and ATP content, a remarkable decrease in conidia yield, and a considerable increase in the number of traps and mycelial loops. In addition, the absence of Aomae1 also caused an obvious reduction in the number of septa and nuclei. In particular, AoMae1 regulates hyphal fusion under low nutrient conditions but not in nutrient-rich conditions, and the volumes and sizes of the lipid droplets dynamically changed during trap formation and nematode predation. AoMae1 is also involved in the regulation of secondary metabolites such as arthrobotrisins. These results suggest that Aomae1 has an important role in hyphal fusion, sporulation, energy production, trap formation, and pathogenicity in A. oligospora. Our results enhance the understanding of the crucial role that enzymes involved in the TCA cycle play in the growth, development, and pathogenicity of NT fungi.
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Affiliation(s)
- Yankun Liu
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Key Laboratory for Southwest Microbial Diversity of the Ministry of Education, School of Life Science, Yunnan University, Kunming 650032, China
| | - Meichen Zhu
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Key Laboratory for Southwest Microbial Diversity of the Ministry of Education, School of Life Science, Yunnan University, Kunming 650032, China
| | - Wenjie Wang
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Key Laboratory for Southwest Microbial Diversity of the Ministry of Education, School of Life Science, Yunnan University, Kunming 650032, China
| | - Xuemei Li
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Key Laboratory for Southwest Microbial Diversity of the Ministry of Education, School of Life Science, Yunnan University, Kunming 650032, China
| | - Na Bai
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Key Laboratory for Southwest Microbial Diversity of the Ministry of Education, School of Life Science, Yunnan University, Kunming 650032, China
| | - Meihua Xie
- School of Resource, Environment and Chemistry, Chuxiong Normal University, Chuxiong 675000, China
| | - Jinkui Yang
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Key Laboratory for Southwest Microbial Diversity of the Ministry of Education, School of Life Science, Yunnan University, Kunming 650032, China
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4
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Bhatia-Kissova I, Camougrand N. Mitophagy in Yeast: Decades of Research. Cells 2021; 10:3541. [PMID: 34944049 PMCID: PMC8700663 DOI: 10.3390/cells10123541] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 12/06/2021] [Accepted: 12/10/2021] [Indexed: 12/02/2022] Open
Abstract
Mitophagy, the selective degradation of mitochondria by autophagy, is one of the most important mechanisms of mitochondrial quality control, and its proper functioning is essential for cellular homeostasis. In this review, we describe the most important milestones achieved during almost 2 decades of research on yeasts, which shed light on the molecular mechanisms, regulation, and role of the Atg32 receptor in this process. We analyze the role of ROS in mitophagy and discuss the physiological roles of mitophagy in unicellular organisms, such as yeast; these roles are very different from those in mammals. Additionally, we discuss some of the different tools available for studying mitophagy.
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Affiliation(s)
- Ingrid Bhatia-Kissova
- Department of Biochemistry, Faculty of Natural Sciences, Comenius University, Ilkovičova 6, 84215 Bratislava, Slovakia;
| | - Nadine Camougrand
- CNRS, UMR 5095, 1 Rue Camille Saint-Saëns, 33077 Bordeaux, France
- Institut de Biochimie et de Génétique Cellulaires, Université de Bordeaux, UMR 5095, 1 Rue Camille Saint-Saëns, 33077 Bordeaux, France
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5
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Hoshida H, Kagawa S, Ogami K, Akada R. Anoxia-induced mitophagy in the yeast Kluyveromyces marxianus. FEMS Yeast Res 2021; 20:5932265. [PMID: 33130889 DOI: 10.1093/femsyr/foaa057] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Accepted: 10/18/2020] [Indexed: 12/13/2022] Open
Abstract
Kluyveromyces marxianus is a thermotolerant, ethanol-producing yeast that requires oxygen for efficient ethanol fermentation. Under anaerobic conditions, glucose consumption and ethanol production are retarded, suggesting that oxygen affects the metabolic state of K. marxianus. Mitochondria require oxygen to function, and their forms and number vary according to environmental conditions. In this study, the effect of anoxia on mitochondrial behavior in K. marxianus was examined. Under aerobic growth conditions, mitochondria-targeted GFP exhibited a tubular and dotted localization, representing a typical mitochondrial morphology, but under anaerobic conditions, GFP localized in vacuoles, suggesting that mitophagy occurs under anaerobic conditions. To confirm mitophagy induction, the ATG32, ATG8, ATG11 and ATG19 genes were disrupted. Vacuolar localization of mitochondria-targeted GFP under anaerobic conditions was interrupted in the Δatg32 and Δatg8 strains but not the Δatg11 and Δatg19 strains. Electron microscopy revealed mitochondria-like membrane components in the vacuoles of wild-type cells grown under anaerobic conditions. Quantitative analyses using mitochondria-targeted Pho8 demonstrated that mitophagy was induced in K. marxianus by anoxia but not nitrogen starvation. To the best of our knowledge, this is the first demonstration of anoxia-induced mitophagy in yeasts.
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Affiliation(s)
- Hisashi Hoshida
- Division of Applied Chemistry, Graduate School of Science and Technology for Innovation, Yamaguchi University, Ube 755-8611, Japan.,Research Center for Thermotolerant Microbial Resources, Yamaguchi University, Yamaguchi 753-8315, Japan.,Yamaguchi University Biomedical Engineering Center, Ube 755-8611, Japan
| | - Shota Kagawa
- Division of Applied Chemistry, Graduate School of Science and Technology for Innovation, Yamaguchi University, Ube 755-8611, Japan
| | - Kentaro Ogami
- Department of Applied Chemistry, Faculty of Engineering, Yamaguchi University, Ube 755-8611, Japan
| | - Rinji Akada
- Division of Applied Chemistry, Graduate School of Science and Technology for Innovation, Yamaguchi University, Ube 755-8611, Japan.,Research Center for Thermotolerant Microbial Resources, Yamaguchi University, Yamaguchi 753-8315, Japan.,Yamaguchi University Biomedical Engineering Center, Ube 755-8611, Japan
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6
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Guan Y, Wang Y, Li B, Shen K, Li Q, Ni Y, Huang L. Mitophagy in carcinogenesis, drug resistance and anticancer therapeutics. Cancer Cell Int 2021; 21:350. [PMID: 34225732 PMCID: PMC8256582 DOI: 10.1186/s12935-021-02065-w] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 06/29/2021] [Indexed: 02/07/2023] Open
Abstract
The mitochondrion is an organelle that plays a vital role in energy production, cytoplasmic protein degradation and cell death. Mitophagy is an autophagic procedure that specifically clears damaged mitochondria and maintains its homeostasis. Emerging evidence indicates that mitophagy is involved in many physiological processes, including cellular homeostasis, cellular differentiation and nerve protection. In this review, we describe the regulatory mechanisms of mitophagy in mammals and yeasts and highlight the recent advances relevant to its function in carcinogenesis and drug resistance. Finally, a section has been dedicated to describing the role of mitophagy in anticancer therapeutics, which is a new frontier that offers a precise and promising strategy.
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Affiliation(s)
- Yanjie Guan
- Department of Histoembryology, Genetics and Developmental Biology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Key Laboratory of Reproductive Medicine, Shanghai Jiao Tong University School of Medicine, 280 South Chongqing Road, Shanghai, 200025, People's Republic of China
| | - Yifei Wang
- Department of Histoembryology, Genetics and Developmental Biology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Key Laboratory of Reproductive Medicine, Shanghai Jiao Tong University School of Medicine, 280 South Chongqing Road, Shanghai, 200025, People's Republic of China
| | - Bo Li
- Department of Histoembryology, Genetics and Developmental Biology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Key Laboratory of Reproductive Medicine, Shanghai Jiao Tong University School of Medicine, 280 South Chongqing Road, Shanghai, 200025, People's Republic of China
| | - Kai Shen
- Department of Histoembryology, Genetics and Developmental Biology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Key Laboratory of Reproductive Medicine, Shanghai Jiao Tong University School of Medicine, 280 South Chongqing Road, Shanghai, 200025, People's Republic of China
| | - Quanfu Li
- Department of Histoembryology, Genetics and Developmental Biology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Key Laboratory of Reproductive Medicine, Shanghai Jiao Tong University School of Medicine, 280 South Chongqing Road, Shanghai, 200025, People's Republic of China.,Innovative Research Team of High-Level Local Universities in Shanghai, Shanghai, People's Republic of China
| | - Yingyin Ni
- Department of Histoembryology, Genetics and Developmental Biology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Key Laboratory of Reproductive Medicine, Shanghai Jiao Tong University School of Medicine, 280 South Chongqing Road, Shanghai, 200025, People's Republic of China. .,Innovative Research Team of High-Level Local Universities in Shanghai, Shanghai, People's Republic of China.
| | - Lei Huang
- Department of Histoembryology, Genetics and Developmental Biology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Key Laboratory of Reproductive Medicine, Shanghai Jiao Tong University School of Medicine, 280 South Chongqing Road, Shanghai, 200025, People's Republic of China. .,Innovative Research Team of High-Level Local Universities in Shanghai, Shanghai, People's Republic of China.
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7
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Huang YJ, Klionsky DJ. Yeast mitophagy: Unanswered questions. Biochim Biophys Acta Gen Subj 2021; 1865:129932. [PMID: 34022298 DOI: 10.1016/j.bbagen.2021.129932] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 05/13/2021] [Accepted: 05/17/2021] [Indexed: 01/18/2023]
Abstract
Superfluous and damaged mitochondria need to be efficiently repaired or removed. Mitophagy is a selective type of autophagy that can engulf a portion of mitochondria within a double-membrane structure, called a mitophagosome, and deliver it to the vacuole for degradation. Mitophagy has significant physiological functions from yeast to human, and recent advances in yeast mitophagy shed light on the molecular mechanisms of mitophagy, especially the regulation of mitophagy induction. This review summarizes our current knowledge about yeast mitophagy and considers several unsolved questions, with a particular focus on Saccharomyces cerevisiae.
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Affiliation(s)
- Yuxiang J Huang
- Life Sciences Institute and Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Daniel J Klionsky
- Life Sciences Institute and Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA.
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8
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Guo Y, Jia X, Cui Y, Song Y, Wang S, Geng Y, Li R, Gao W, Fu D. Sirt3-mediated mitophagy regulates AGEs-induced BMSCs senescence and senile osteoporosis. Redox Biol 2021; 41:101915. [PMID: 33662874 PMCID: PMC7930642 DOI: 10.1016/j.redox.2021.101915] [Citation(s) in RCA: 106] [Impact Index Per Article: 35.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 02/19/2021] [Accepted: 02/19/2021] [Indexed: 02/09/2023] Open
Abstract
Senile osteoporosis (SOP) is widely regarded as one of the typical aging-related diseases due to a decrease in bone mass and the destruction in microarchitecture. The inhibition of mitophagy can promote bone marrow mesenchymal stem cells (BMSCs) senescence, and increasing studies have shown that interventions targeting BMSCs senescence can ameliorate osteoporosis, exhibiting their potential for use as therapeutic strategies. Sirtuin-3 (Sirt3) is an essential mitochondria metabolic regulatory enzyme that plays an important role in mitochondrial homeostasis, but its role in bone homeostasis remains largely unknown. This study seeks to investigate whether advanced glycation end products (AGEs) accumulation aggravated BMSCs senescence and SOP, and explored the mechanisms underlying these effects. We observed that AGEs significantly aggravated BMSCs senescence, as well as promoted mitochondrial dysfunction and inhibited mitophagy in a concentration-dependent manner. In addition, this effect could be further strengthened by Sirt3 silencing. Importantly, we identified that the reduction of Sirt3 expression and the mitophagy were vital mechanisms in AGEs-induced BMSCs senescence. Furthermore, overexpression of Sirt3 by intravenously injection with recombinant adeno-associated virus 9 carrying Sirt3 plasmids (rAAV-Sirt3) significantly alleviated BMSCs senescence and the formation of SOP in SAMP6. In conclusion, our data demonstrated that Sirt3 protects against AGEs-induced BMSCs senescence and SOP. Targeting Sirt3 to improve mitophagy may represent a potential therapeutic strategy for attenuating AGEs-associated SOP.
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Affiliation(s)
- Yuanyuan Guo
- Department of Pharmacy, Liyuan Hospital, Tongji Medical College, Huazhong University of Science and Technology, China; Department of Cardiovascular Diseases, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, China
| | - Xiong Jia
- Department of Cardiovascular Diseases, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, China
| | - Yongzhi Cui
- Department of Orthopaedics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, China
| | - Yu Song
- Department of Orthopaedics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, China
| | - Siyuan Wang
- Department of Orthopaedics, Liyuan Hospital, Tongji Medical College, Huazhong University of Science and Technology, China
| | - Yongtao Geng
- Department of Orthopaedics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, China
| | - Rui Li
- Department of Orthopaedics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, China
| | - Weihang Gao
- Department of Orthopaedics, Liyuan Hospital, Tongji Medical College, Huazhong University of Science and Technology, China
| | - Dehao Fu
- Department of Orthopaedics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, China.
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9
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Brito MD, Silva LFSE, Siena A, Chipara M, Sarkar S, Rosenstock TR. Oxygen Consumption Evaluation: An Important Indicator of Metabolic State, Cellular Function, and Cell Fate Along Neural Deregulation. Methods Mol Biol 2021; 2240:207-230. [PMID: 33423236 DOI: 10.1007/978-1-0716-1091-6_15] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Depletion of oxygen (O2) levels and reduction in the ATP synthesis (or even its complete blockage) are important characteristics of mitochondrial dysfunction; features that are often correlated with neurodegeneration. The measurement of oxygen consumption rate (OCR) is thus essential to evaluate cellular metabolism, survival, and neuroprotective strategies. In the present chapter, we describe the oxygen consumption assay using a Clark-type oxygen electrode in different types of samples named cells suspension (from primary and established cell culture), brain slices (ex vivo), and fresh brain tissues. In addition, we demonstrate herein how the program Oxygraph can be used in order to analyze the data and different approaches to normalize it.
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Affiliation(s)
- Mariana Dutra Brito
- Department of Physiological Science, Santa Casa de São Paulo School of Medical Science. R. Doutor Cesário Motta Júnior, São Paulo, SP, Brazil
| | - Luiz Felipe Souza E Silva
- Department of Physiological Science, Santa Casa de São Paulo School of Medical Science. R. Doutor Cesário Motta Júnior, São Paulo, SP, Brazil
| | - Amanda Siena
- Department of Physiological Science, Santa Casa de São Paulo School of Medical Science. R. Doutor Cesário Motta Júnior, São Paulo, SP, Brazil
| | - Miruna Chipara
- Institute of Cancer and Genomic Sciences, Institute of Biomedical Research, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Sovan Sarkar
- Institute of Cancer and Genomic Sciences, Institute of Biomedical Research, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Tatiana Rosado Rosenstock
- Department of Pharmacology, Institute of Biomedical Science, University of São Paulo, São Paulo, Brazil. .,Institute of Cancer and Genomic Sciences, Institute of Biomedical Research, College of Medical and dental Sciences, University of Birmingham, Birmingham, UK.
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10
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Qiu YH, Zhang TS, Wang XW, Wang MY, Zhao WX, Zhou HM, Zhang CH, Cai ML, Chen XF, Zhao WL, Shao RG. Mitochondria autophagy: a potential target for cancer therapy. J Drug Target 2021; 29:576-591. [PMID: 33554661 DOI: 10.1080/1061186x.2020.1867992] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Mitophagy is a selective form of macroautophagy in which dysfunctional and damaged mitochondria can be efficiently degraded, removed and recycled through autophagy. Selective removal of damaged or fragmented mitochondria is critical to the functional integrity of the entire mitochondrial network and cells. In past decades, numerous studies have shown that mitophagy is involved in various diseases; however, since the dual role of mitophagy in tumour development, mitophagy role in tumour is controversial, and further elucidation is needed. That is, although mitophagy has been demonstrated to contribute to carcinogenesis, cell migration, ferroptosis inhibition, cancer stemness maintenance, tumour immune escape, drug resistance, etc. during cancer progression, many research also shows that to promote cancer cell death, mitophagy can be induced physiologically or pharmacologically to maintain normal cellular metabolism and prevent cell stress responses and genome damage by diminishing mitochondrial damage, thus suppressing tumour development accompanying these changes. Signalling pathway-specific molecular mechanisms are currently of great biological significance in the identification of potential therapeutic targets. Here, we review recent progress of molecular pathways mediating mitophagy including both canonical pathways (Parkin/PINK1- and FUNDC1-mediated mitophagy) and noncanonical pathways (FKBP8-, Nrf2-, and DRP1-mediated mitophagy); and the regulation of these pathways, and abovementioned pro-cancer and pro-death roles of mitophagy. Finally, we summarise the role of mitophagy in cancer therapy. Mitophagy can potentially be acted as the target for cancer therapy by promotion or inhibition.
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Affiliation(s)
- Yu-Han Qiu
- Key Laboratory of Antibiotic Bioengineering, Ministry of Health, Laboratory of Oncology, Institute of Medicinal Biotechnology, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
| | - Tian-Shu Zhang
- Key Laboratory of Antibiotic Bioengineering, Ministry of Health, Laboratory of Oncology, Institute of Medicinal Biotechnology, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
| | - Xiao-Wei Wang
- Key Laboratory of Antibiotic Bioengineering, Ministry of Health, Laboratory of Oncology, Institute of Medicinal Biotechnology, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
| | - Meng-Yan Wang
- Key Laboratory of Antibiotic Bioengineering, Ministry of Health, Laboratory of Oncology, Institute of Medicinal Biotechnology, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
| | - Wen-Xia Zhao
- Key Laboratory of Antibiotic Bioengineering, Ministry of Health, Laboratory of Oncology, Institute of Medicinal Biotechnology, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
| | - Hui-Min Zhou
- Key Laboratory of Antibiotic Bioengineering, Ministry of Health, Laboratory of Oncology, Institute of Medicinal Biotechnology, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
| | - Cong-Hui Zhang
- Key Laboratory of Antibiotic Bioengineering, Ministry of Health, Laboratory of Oncology, Institute of Medicinal Biotechnology, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
| | - Mei-Lian Cai
- Key Laboratory of Antibiotic Bioengineering, Ministry of Health, Laboratory of Oncology, Institute of Medicinal Biotechnology, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
| | - Xiao-Fang Chen
- Key Laboratory of Antibiotic Bioengineering, Ministry of Health, Laboratory of Oncology, Institute of Medicinal Biotechnology, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
| | - Wu-Li Zhao
- Key Laboratory of Antibiotic Bioengineering, Ministry of Health, Laboratory of Oncology, Institute of Medicinal Biotechnology, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
| | - Rong-Guang Shao
- Key Laboratory of Antibiotic Bioengineering, Ministry of Health, Laboratory of Oncology, Institute of Medicinal Biotechnology, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
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11
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Mao X, Yang L, Fan Y, Wang J, Cui D, Yu D, Yu Q, Li M. The Vacuole and Mitochondria Patch (vCLAMP) Protein Mcp1 Is Involved in Maintenance of Mitochondrial Function and Mitophagy in Candida albicans. Front Microbiol 2021; 12:633380. [PMID: 33633712 PMCID: PMC7902011 DOI: 10.3389/fmicb.2021.633380] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Accepted: 01/18/2021] [Indexed: 12/12/2022] Open
Abstract
The vacuole and mitochondria patches (vCLAMPs) are novel membrane contact sites in yeast. However, their role in autophagy has not been elucidated so far. In this article, the role of Mcp1, one core component of vCLAMP, in mitophagy of Candida albicans was investigated. Deletion of MCP1 led to abnormal accumulation of enlarged mitochondria and attenuated stability of mitochondrial DNA (mtDNA) in C. albicans when cultured in non-fermentable carbon sources. Furthermore, the mcp1Δ/Δ mutant exhibited defective growth and degradation of Csp37-GFP. These results indicate that Mcp1 plays a crucial role in mitophagy and maintenance of mitochondrial functions under the non-fermentable condition. Interestingly, this deletion had no impact on degradation of Atg8 (the macroautophagy reporter) and Lap41 (the cytoplasm-to-vacuole targeting pathway marker) under SD-N medium. Moreover, deletion of MCP1 inhibited filamentous growth and impaired virulence of the pathogen. This study provides an insight to vCLAMPs in cellular functions and pathogenicity in C. albicans.
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Affiliation(s)
- Xiaolong Mao
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Science, Nankai University, Tianjin, China
| | - Li Yang
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Science, Nankai University, Tianjin, China
| | - Yiming Fan
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Science, Nankai University, Tianjin, China
| | - Jiazhen Wang
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Science, Nankai University, Tianjin, China
| | - Dongkai Cui
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Science, Nankai University, Tianjin, China
| | - Dixiong Yu
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Science, Nankai University, Tianjin, China
| | - Qilin Yu
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Science, Nankai University, Tianjin, China
| | - Mingchun Li
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Science, Nankai University, Tianjin, China
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12
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Mitochondrial Dysfunction in Intervertebral Disc Degeneration: From Pathogenesis to Therapeutic Target. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2020. [DOI: 10.1155/2020/8880320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Mitochondria are cytosolic organelles essential for cellular function and survival. The function of mitochondria is maintained by mitochondrial quality control systems including mitochondrial fission and fusion to adapt the altered environment and mitophagy for removal of damaged mitochondria. Mitochondrial dysfunction is closely involved in aging-related diseases. Intervertebral disc (IVD) degeneration, an aging-associated process, is the major contributor to low back pain. Growing evidence has suggested that the mitochondrial function in IVD cells is severely compromised during the degenerative process of IVD, and dysfunctional mitochondria along with impaired mitochondrial dynamics and mitophagy cause a series of cascade reactions that have been implicated in increased oxidative stress, senescence, matrix catabolism, and apoptosis of IVD cells, thereby contributing to the degeneration of IVD. Accordingly, therapies that target mitochondrial dysfunction and related mechanisms, such as ROS generation, mitophagy, and specific molecules and signaling, hold great promise. The present review summarizes the current state of the role of mitochondrial dysfunction in the pathophysiology of IVD degeneration and potential therapeutic strategies that could be developed.
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13
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Zhao Y, Yang N, Deng Y, Tao K, Jin H, Hou T. Mechanism of Action of Novel Pyrazole Carboxamide Containing a Diarylamine Scaffold against Rhizoctonia solani. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2020; 68:11068-11076. [PMID: 32924467 DOI: 10.1021/acs.jafc.9b06937] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
In the last few decades, Rhizoctonia solani causing rice sheath blight has resulted in a lot of economic losses in the world. Therefore, many novel pyrazole carboxamide fungicides have been intensively researched and employed to fight against it. In this regard, in recent years, our group reported a novel pyrazole carboxamide containing a diarylamine scaffold with good antifungal activity against rice sheath blight in the pot test and field trial. Following this project, the antifungal mechanism of action of the pyrazole carboxamide has been elucidated in this work. The antifungal result showed that compound SCU2028, N-[2-[(3-chlorophenyl)amino]-phenyl]-3-(difluoromethyl)-1-methyl-1H-pyrazole-4-carboxamide, was equivalent to the commercial fungicide thifluzamide and its EC50 value was 0.022 mg/L against R. solani. Also, the observation results by scanning electron microscopy and transmission electron microscopy showed that it could destroy the fungus' cell walls or membranes and result in the leakage of contents and increase of the number of mitochondria and abnormal morphology. Meanwhile, the result on the mitochondrial membrane potential (MMP) showed that it could decrease R. solani's MMP. Furthermore, the results by label-free quantitative proteomic analysis showed that 1153 proteins were found after R. solani was treated with compound SCU2028, including 212 proteins in the control group and 257 proteins in the treatment group. A total of 142 differential proteins were obtained, of which 92 proteins were upregulated and 50 proteins were downregulated. The differentially expressed proteins affected a series of physiological and biochemical pathways in the mitochondria, endoplasmic reticulum, ribosome, and other related GO and KEGG pathways. In particular, the inhibition of the respiratory chain caused by the TCA cycle and oxidative phosphorylation KEGG pathway indicated that complex II (succinate dehydrogenase) and complex IV (cytochrome oxidase) might be compound SCU2028's main action targets. In addition, multiple experiments of qRT-PCR, enzyme activity detection, and molecular docking confirmed complex II and complex IV as targets. It could be seen that these findings provided a theoretical support for further research and development of the pyrazole carboxamide fungicides.
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Affiliation(s)
- Yongtian Zhao
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, Sichuan 610065, China
- College of Agroforestry and Health, Sichuan Radio and TV University, Chengdu, Sichuan 610073, China
| | - Na Yang
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, Sichuan 610065, China
| | - Yiming Deng
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, Sichuan 610065, China
| | - Ke Tao
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, Sichuan 610065, China
| | - Hong Jin
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, Sichuan 610065, China
| | - Taiping Hou
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, Sichuan 610065, China
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14
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Kreimendahl S, Rassow J. The Mitochondrial Outer Membrane Protein Tom70-Mediator in Protein Traffic, Membrane Contact Sites and Innate Immunity. Int J Mol Sci 2020; 21:E7262. [PMID: 33019591 PMCID: PMC7583919 DOI: 10.3390/ijms21197262] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 09/25/2020] [Accepted: 09/28/2020] [Indexed: 02/08/2023] Open
Abstract
Tom70 is a versatile adaptor protein of 70 kDa anchored in the outer membrane of mitochondria in metazoa, fungi and amoeba. The tertiary structure was resolved for the Tom70 of yeast, showing 26 α-helices, most of them participating in the formation of 11 tetratricopeptide repeat (TPR) motifs. Tom70 serves as a docking site for cytosolic chaperone proteins and co-chaperones and is thereby involved in the uptake of newly synthesized chaperone-bound proteins in mitochondrial biogenesis. In yeast, Tom70 additionally mediates ER-mitochondria contacts via binding to sterol transporter Lam6/Ltc1. In mammalian cells, TOM70 promotes endoplasmic reticulum (ER) to mitochondria Ca2+ transfer by association with the inositol-1,4,5-triphosphate receptor type 3 (IP3R3). TOM70 is specifically targeted by the Bcl-2-related protein MCL-1 that acts as an anti-apoptotic protein in macrophages infected by intracellular pathogens, but also in many cancer cells. By participating in the recruitment of PINK1 and the E3 ubiquitin ligase Parkin, TOM70 can be implicated in the development of Parkinson's disease. TOM70 acts as receptor of the mitochondrial antiviral-signaling protein (MAVS) and thereby participates in the corresponding system of innate immunity against viral infections. The protein encoded by Orf9b in the genome of SARS-CoV-2 binds to TOM70, probably compromising the synthesis of type I interferons.
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Affiliation(s)
| | - Joachim Rassow
- Institute for Biochemistry and Pathobiochemistry, Ruhr-University Bochum, 44801 Bochum, Germany;
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15
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Role of DRAM1 in mitophagy contributes to preeclampsia regulation in mice. Mol Med Rep 2020; 22:1847-1858. [PMID: 32582984 PMCID: PMC7411365 DOI: 10.3892/mmr.2020.11269] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Accepted: 06/02/2020] [Indexed: 02/06/2023] Open
Abstract
Preeclampsia (PE) is a complication during pregnancy that is diagnosed by a new onset of hypertension and proteinuria. Although the pathogenesis of PE is not fully understood, a growing body of evidence indicates that oxidative stress and mitochondrial dysfunction might contribute to the progression of PE. Therefore, the aim of the present study was to determine the role of mitophagy in mitochondrial dysfunction and oxidative stress in PE, and to evaluate the role of DNA damage‑regulated autophagy modulator 1 (DRAM1) in the development of PE. First, a mouse model of PE induced by hypoxia‑inducible factor 1α was established, and high levels of oxidative stress, apoptosis and mitochondrial dysfunction were found in the placentas of PE mice. Additionally, the placentas of PE mice exhibited decreased mitophagy and significantly decreased DRAM1 expression. To further explore the role of DRAM1 in mitophagy, DRAM1 was overexpressed in the placental tissues of PE mice, and this overexpression effectively improved the symptoms of PE mice and significantly reduced blood lipid and urine protein levels. DRAM1 overexpression also improved mitochondrial function and reduced oxidative stress in the placentas of PE mice. In addition, the overexpression of DRAM1 improved mitochondrial fusion and fission, and enhanced mitophagy. Altogether, these results indicated a key role for DRAM1 in mitophagy that contributed to the regulation of PE. To the best of the authors' knowledge, the present study provided the first evidence of a role for DRAM1 in PE, and offered novel insight into the pathophysiological mechanisms of PE.
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16
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Wang Y, Liu HH, Cao YT, Zhang LL, Huang F, Yi C. The Role of Mitochondrial Dynamics and Mitophagy in Carcinogenesis, Metastasis and Therapy. Front Cell Dev Biol 2020; 8:413. [PMID: 32587855 PMCID: PMC7297908 DOI: 10.3389/fcell.2020.00413] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Accepted: 05/04/2020] [Indexed: 12/24/2022] Open
Abstract
Mitochondria are key cellular organelles and play vital roles in energy metabolism, apoptosis regulation and cellular homeostasis. Mitochondrial dynamics refers to the varying balance between mitochondrial fission and mitochondrial fusion that plays an important part in maintaining mitochondrial homeostasis and quality. Mitochondrial malfunction is involved in aging, metabolic disease, neurodegenerative disorders, and cancers. Mitophagy, a selective autophagy of mitochondria, can efficiently degrade, remove and recycle the malfunctioning or damaged mitochondria, and is crucial for quality control. In past decades, numerous studies have identified a series of factors that regulate mitophagy and are also involved in carcinogenesis, cancer cell migration and death. Therefore, it has become critically important to analyze signal pathways that regulate mitophagy to identify potential therapeutic targets. Here, we review recent progresses in mitochondrial dynamics, the mechanisms of mitophagy regulation, and the implications for understanding carcinogenesis, metastasis, treatment, and drug resistance.
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Affiliation(s)
- Yigang Wang
- Xinyuan Institute of Medicine and Biotechnology, School of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, China
| | - Hui-Hui Liu
- Xinyuan Institute of Medicine and Biotechnology, School of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, China
| | - Yu-Ting Cao
- Xinyuan Institute of Medicine and Biotechnology, School of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, China
| | - Lei-Lei Zhang
- Xinyuan Institute of Medicine and Biotechnology, School of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, China
| | - Fang Huang
- Department of Pathology, Zhejiang Provincial People's Hospital, People's Hospital of Hangzhou Medical College, Hangzhou, China
| | - Cong Yi
- Department of Biochemistry, Hepatobiliary and Pancreatic Surgery, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
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17
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Ferdouse J, Kusaba Y, Fujimaru Y, Yamamoto Y, Kitagaki H. Methionine and Glycine Stabilize Mitochondrial Activity in Sake Yeast During Ethanol Fermentation. Food Technol Biotechnol 2020; 57:535-543. [PMID: 32123515 PMCID: PMC7029386 DOI: 10.17113/ftb.57.04.19.5665] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Addition of amino acids to fermentation media affects the growth and brewing profiles of yeast. In addition, retaining mitochondrial activity during fermentation is critical for the fermentation profiles of brewer’s yeasts. However, a concrete mechanism linking amino acids in fermentation media with mitochondrial activity during fermentation of brewer’s yeasts is yet unknown. Here, we report that amino acids in fermentation media, especially methionine (Met) and glycine (Gly), stabilize mitochondrial activity during fermentation of sake yeast. By utilizing atg32△ mutant sake yeast, which shows deteriorated mitochondrial activity, we screened candidate amino acids that strengthened the mitochondrial activity of sake yeast during fermentation. We identified Met and Gly as candidate amino acids that fortify mitochondrial activity in sake yeast during fermentation. To confirm this biochemically, we measured reactive oxygen species (ROS) levels in sake yeast fermented with Met and Gly. Yeast cells supplemented with Met and Gly retained high ROS levels relative to the non-supplemented sake yeast. Moreover, Met-supplemented cells showed a metabolome distinct from that of non-supplemented cells. These results indicate that specific amino acids such as Met and Gly stabilize the mitochondrial activity of sake yeast during fermentation and thus manipulate brewing profiles of yeast.
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Affiliation(s)
- Jannatul Ferdouse
- Department of Environmental Science, Faculty of Agriculture, Saga University, Saga City, Saga 840-8502, Japan.,Department of Biochemistry and Applied Biosciences, United Graduate School of Agricultural Sciences, Kagoshima University, 1-21-24, Korimoto, Kagoshima 890-8580, Japan.,Department of Microbiology, Faculty of Biological Sciences, University of Chittagong, Chittagong 4331, Bangladesh
| | - Yuki Kusaba
- Department of Environmental Science, Faculty of Agriculture, Saga University, Saga City, Saga 840-8502, Japan
| | - Yuki Fujimaru
- Department of Environmental Science, Faculty of Agriculture, Saga University, Saga City, Saga 840-8502, Japan
| | - Yuki Yamamoto
- Department of Environmental Science, Faculty of Agriculture, Saga University, Saga City, Saga 840-8502, Japan
| | - Hiroshi Kitagaki
- Department of Environmental Science, Faculty of Agriculture, Saga University, Saga City, Saga 840-8502, Japan.,Department of Biochemistry and Applied Biosciences, United Graduate School of Agricultural Sciences, Kagoshima University, 1-21-24, Korimoto, Kagoshima 890-8580, Japan
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18
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Dai XG, Xu W, Li T, Lu JY, Yang Y, Li Q, Zeng ZH, Ai YH. Involvement of phosphatase and tensin homolog-induced putative kinase 1-Parkin-mediated mitophagy in septic acute kidney injury. Chin Med J (Engl) 2019; 132:2340-2347. [PMID: 31567378 PMCID: PMC6819035 DOI: 10.1097/cm9.0000000000000448] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Studies have reported mitophagy activation in renal tubular epithelial cells (RTECs) in acute kidney injury (AKI). Phosphatase and tensin homolog-induced putative kinase 1 (PINK1) and E3 ubiquitin-protein ligase Parkin are involved in mitophagy regulation; however, little is known about the role of PINK1-Parkin mitophagy in septic AKI. Here we investigated whether the PINK1-Parkin mitophagy pathway is involved in septic AKI and its effects on cell apoptosis in vitro and on renal functions in vivo. METHODS Mitophagy-related gene expression was determined using Western blot assay in human RTEC cell line HK-2 stimulated with bacterial lipopolysaccharide (LPS) and in RTECs from septic AKI rats induced by cecal ligation and perforation (CLP). Autophagy-related ultrastructural features in rat RTECs were observed using electron microscopy. Gain- and loss-of-function approaches were performed to investigate the role of the PINK1-Parkin pathway in HK-2 cell mitophagy. Autophagy activators and inhibitors were used to assess the effects of mitophagy modulation on cell apoptosis in vitro and on renal functions in vivo. RESULTS LPS stimulation could significantly induce LC3-II and BECN-1 protein expression (LC3-II: 1.72 ± 0.05 vs. 1.00 ± 0.05, P < 0.05; BECN-1: 5.33 ± 0.57 vs. 1.00 ± 0.14, P < 0.05) at 4 h in vitro. Similarly, LC3-II, and BECN-1 protein levels were significantly increased and peaked at 2 h after CLP (LC3-II: 3.33 ± 0.12 vs. 1.03 ± 0.15, P < 0.05; BECN-1: 1.57 ± 0.26 vs. 1.02 ± 0.11, P < 0.05) in vivo compared with those after sham operation. Mitochondrial deformation and mitolysosome-mediated mitochondria clearance were observed in RTECs from septic rats. PINK1 knockdown significantly attenuated LC3-II protein expression (1.35 ± 0.21 vs. 2.38 ± 0.22, P < 0.05), whereas PINK1 overexpression markedly enhanced LC3-II protein expression (2.07 ± 0.21 vs. 1.29 ± 0.19, P < 0.05) compared with LPS-stimulated HK-2 cells. LPS-induced proapoptotic protein expression remained unchanged in autophagy activator-treated HK-2 cells and was significantly attenuated in PINK1-overexpressing cells, but was remarkably upregulated in autophagy inhibitor-treated and in PINK1-depleted cells. Consistent results were observed in flow cytometric apoptosis assay and in renal function indicators in rats. CONCLUSION PINK1-Parkin-mediated mitophagy might play a protective role in septic AKI, serving as a potential therapeutic target for septic AKI.
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Affiliation(s)
- Xin-Gui Dai
- Department of Intensive Care Unit, Xiangya Hospital, Central South University, Changsha, Hunan 410078, China
- Department of Critical Care Medicine, The First People's Hospital of Chenzhou, Chenzhou, Hunan 423000, China
| | - Wei Xu
- Department of Critical Care Medicine, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong 510515, China
| | - Tao Li
- Department of Critical Care Medicine, The First People's Hospital of Chenzhou, Chenzhou, Hunan 423000, China
| | - Jia-Ying Lu
- Department of Critical Care Medicine, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong 510515, China
| | - Yang Yang
- Department of Critical Care Medicine, The First People's Hospital of Chenzhou, Chenzhou, Hunan 423000, China
| | - Qiong Li
- Department of Critical Care Medicine, The First People's Hospital of Chenzhou, Chenzhou, Hunan 423000, China
| | - Zhen-Hua Zeng
- Department of Critical Care Medicine, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong 510515, China
| | - Yu-Hang Ai
- Department of Intensive Care Unit, Xiangya Hospital, Central South University, Changsha, Hunan 410078, China
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19
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Ueda S, Ozaki R, Kaneko A, Akizuki R, Katsuta H, Miura A, Matsuura A, Ushimaru T. TORC1, Tel1/Mec1, and Mpk1 regulate autophagy induction after DNA damage in budding yeast. Cell Signal 2019; 62:109344. [DOI: 10.1016/j.cellsig.2019.109344] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 06/10/2019] [Accepted: 06/10/2019] [Indexed: 02/08/2023]
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20
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Park YS, Choi SE, Koh HC. PGAM5 regulates PINK1/Parkin-mediated mitophagy via DRP1 in CCCP-induced mitochondrial dysfunction. Toxicol Lett 2017; 284:120-128. [PMID: 29241732 DOI: 10.1016/j.toxlet.2017.12.004] [Citation(s) in RCA: 111] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Revised: 11/30/2017] [Accepted: 12/09/2017] [Indexed: 12/19/2022]
Abstract
Mitochondrial dynamics and mitophagy are critical processes for regulating mitochondrial homeostasis. Phosphoglycerate mutase family member 5 (PGAM5) is a mitochondrial protein that plays crucial roles in apoptosis and necroptosis, but the roles of PGAM5 in mitochondrial dynamics and mitophagy remain unclear. In this study, we investigated the role of PGAM5 in carbonyl cyanide m-chlorophenylhydrazone (CCCP)-induced mitochondrial damage and the correlation between mitochondrial dynamics and mitophagy using SH-SY5Y cells. We found that CCCP decreased mitochondrial membrane potential, resulting in mitochondrial dysfunction. CCCP increased PGAM5, dynamin-related protein 1 (DRP1), and optic atrophy 1 (OPA1) expression of the mitochondrial fraction in a time-dependent manner. Knockdown of PGAM5 inhibited DRP1 translocation without a change in OPA1 expression in CCCP-treated cells. Furthermore, knockdown of PGAM5 and DRP1 significantly blocked the increase of PTEN-induced putative protein kinase 1 (PINK1) and Parkin expression in the mitochondrial fraction of CCCP-treated cells. Interestingly, CCCP did not alter PINK1/Parkin expression in the mitochondrial fraction of OPA1 knockdown cells. Inhibiting mitophagy by PGAM5 knockdown accelerated CCCP-induced apoptosis. CCCP treatment also results in PINK1 stabilization on the mitochondrial membrane, which subsequently increases Parkin recruitment from the cytosol to abnormal mitochondria. In addition, we found that CCCP increased the level of mitochondrial LC3II, indicating that Parkin recruitment of PINK1 is a result of mitophagy. We propose that activation of PGAM5 is associated with DRP1 recruitment and PINK1 stabilization, which contribute to the modulation of mitophagy in CCCP-treated cells with mitochondrial dysfunction. In conclusion, we demonstrated that PGAM5 regulates PINK1-Parkin-mediated mitophagy, which can exert a neuroprotective effect against CCCP-induced apoptosis.
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Affiliation(s)
- Yun Sun Park
- Department of Pharmacology, College of Medicine, Hanyang University, Seoul, Republic of Korea; Graduate School of Biomedical Science and Engineering, Hanyang University, Seoul, Republic of Korea
| | - Su Eun Choi
- Department of Pharmacology, College of Medicine, Hanyang University, Seoul, Republic of Korea; Graduate School of Biomedical Science and Engineering, Hanyang University, Seoul, Republic of Korea
| | - Hyun Chul Koh
- Department of Pharmacology, College of Medicine, Hanyang University, Seoul, Republic of Korea; Hanyang Biomedical Research Institute, Seoul, Republic of Korea; Graduate School of Biomedical Science and Engineering, Hanyang University, Seoul, Republic of Korea.
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21
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Seo AY, Lau PW, Feliciano D, Sengupta P, Gros MAL, Cinquin B, Larabell CA, Lippincott-Schwartz J. AMPK and vacuole-associated Atg14p orchestrate μ-lipophagy for energy production and long-term survival under glucose starvation. eLife 2017; 6. [PMID: 28394250 PMCID: PMC5407857 DOI: 10.7554/elife.21690] [Citation(s) in RCA: 115] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Accepted: 04/09/2017] [Indexed: 12/22/2022] Open
Abstract
Dietary restriction increases the longevity of many organisms, but the cell signaling and organellar mechanisms underlying this capability are unclear. We demonstrate that to permit long-term survival in response to sudden glucose depletion, yeast cells activate lipid-droplet (LD) consumption through micro-lipophagy (µ-lipophagy), in which fat is metabolized as an alternative energy source. AMP-activated protein kinase (AMPK) activation triggered this pathway, which required Atg14p. More gradual glucose starvation, amino acid deprivation or rapamycin did not trigger µ-lipophagy and failed to provide the needed substitute energy source for long-term survival. During acute glucose restriction, activated AMPK was stabilized from degradation and interacted with Atg14p. This prompted Atg14p redistribution from ER exit sites onto liquid-ordered vacuole membrane domains, initiating µ-lipophagy. Our findings that activated AMPK and Atg14p are required to orchestrate µ-lipophagy for energy production in starved cells is relevant for studies on aging and evolutionary survival strategies of different organisms. DOI:http://dx.doi.org/10.7554/eLife.21690.001
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Affiliation(s)
- Arnold Y Seo
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States.,Cell Biology and Metabolism Program, National Institutes of Health, Bethesda, United States
| | - Pick-Wei Lau
- Cell Biology and Metabolism Program, National Institutes of Health, Bethesda, United States
| | - Daniel Feliciano
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States.,Cell Biology and Metabolism Program, National Institutes of Health, Bethesda, United States
| | - Prabuddha Sengupta
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States.,Cell Biology and Metabolism Program, National Institutes of Health, Bethesda, United States
| | - Mark A Le Gros
- Department of Anatomy, University of California, San Francisco, San Francisco, United States.,Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, United States
| | - Bertrand Cinquin
- Department of Anatomy, University of California, San Francisco, San Francisco, United States
| | - Carolyn A Larabell
- Department of Anatomy, University of California, San Francisco, San Francisco, United States.,Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, United States
| | - Jennifer Lippincott-Schwartz
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States.,Cell Biology and Metabolism Program, National Institutes of Health, Bethesda, United States
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22
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Al-Anzi B, Gerges S, Olsman N, Ormerod C, Piliouras G, Ormerod J, Zinn K. Modeling and analysis of modular structure in diverse biological networks. J Theor Biol 2017; 422:18-30. [PMID: 28396125 DOI: 10.1016/j.jtbi.2017.04.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2016] [Revised: 03/28/2017] [Accepted: 04/04/2017] [Indexed: 01/06/2023]
Abstract
Biological networks, like most engineered networks, are not the product of a singular design but rather are the result of a long process of refinement and optimization. Many large real-world networks are comprised of well-defined and meaningful smaller modules. While engineered networks are designed and refined by humans with particular goals in mind, biological networks are created by the selective pressures of evolution. In this paper, we seek to define aspects of network architecture that are shared among different types of evolved biological networks. First, we developed a new mathematical model, the Stochastic Block Model with Path Selection (SBM-PS) that simulates biological network formation based on the selection of edges that increase clustering. SBM-PS can produce modular networks whose properties resemble those of real networks. Second, we analyzed three real networks of very different types, and showed that all three can be fit well by the SBM-PS model. Third, we showed that modular elements within the three networks correspond to meaningful biological structures. The networks chosen for analysis were a proteomic network composed of all proteins required for mitochondrial function in budding yeast, a mesoscale anatomical network composed of axonal connections among regions of the mouse brain, and the connectome of individual neurons in the nematode C. elegans. We find that the three networks have common architectural features, and each can be divided into subnetworks with characteristic topologies that control specific phenotypic outputs.
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Affiliation(s)
- Bader Al-Anzi
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125 USA.
| | - Sherif Gerges
- Medical and Population Genetics, Broad Institute of Harvard and MIT, Cambridge, MA 02142 USA; Analytical and Translational Genetics Unit, Massachusetts General Hospital, Boston, MA 02114, USA; Program in Biological and Biomedical Sciences, Harvard Medical School, Boston, MA 02115, USA
| | - Noah Olsman
- Control and Dynamical Systems Option, Division of Engineering and Applied Sciences, California Institute of Technology Pasadena, CA 91125 USA
| | - Christopher Ormerod
- Division of Physics, Mathematics, and Astronomy, California Institute of Technology, Pasadena, CA 91125 USA ; Department of Mathematics and Statistics, University of Maine, Orono, ME 04469-5752, USA
| | - Georgios Piliouras
- Singapore University of Technology and Design, Engineering Systems and Design (ESD), 8 Somapah Road, 487372 Singapore
| | - John Ormerod
- School of Mathematics and Statistics F07, University of Sydney, NSW 2006, Australia
| | - Kai Zinn
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125 USA.
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Wu L, Xu W, Xu L, Kong Q, Fang J. Mitophagy is increased during erythroid differentiation in β-thalassemia. Int J Hematol 2016; 105:162-173. [PMID: 27796739 DOI: 10.1007/s12185-016-2114-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Revised: 10/13/2016] [Accepted: 10/18/2016] [Indexed: 01/29/2023]
Abstract
Mitophagy is a selective degradation of mitochondria, which also plays a critical role in hematopoiesis. However, it is unclear what role, if any, this process plays in the pathogenesis of β-thalassemia. To determine the role of mitophagy in β-thalassemia, CD34+ hematopoietic progenitor cells (HPCs) were isolated from peripheral blood of β-thalassemia patients and healthy controls and differentiated into erythrocytes. We found that the ratio of mitochondrial membrane depolarization was significantly increased, and that mitochondria co-localize with lysosomes at a higher level in β-thalassemia compared with control. Furthermore, the expression of LC3-II and Nix, as well as degradation of p62, in β-thalassemia was higher than in the control. In sum, our data suggest that selective mitophagy is enhanced during erythrocyte differentiation in β-thalassemia.
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Affiliation(s)
- Limei Wu
- Department of Pediatrics, The Second Affiliated Hospital of Sun Yat-Sen University, No. 107, Yan Jiang Road W., Guangzhou, 510120, People's Republic of China
| | - Wei Xu
- Department of Pediatrics, The Second Affiliated Hospital of Sun Yat-Sen University, No. 107, Yan Jiang Road W., Guangzhou, 510120, People's Republic of China
| | - Luhong Xu
- Department of Pediatrics, The Second Affiliated Hospital of Sun Yat-Sen University, No. 107, Yan Jiang Road W., Guangzhou, 510120, People's Republic of China
| | - Qian Kong
- Department of Pediatrics, The Second Affiliated Hospital of Sun Yat-Sen University, No. 107, Yan Jiang Road W., Guangzhou, 510120, People's Republic of China
| | - Jianpei Fang
- Department of Pediatrics, The Second Affiliated Hospital of Sun Yat-Sen University, No. 107, Yan Jiang Road W., Guangzhou, 510120, People's Republic of China.
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24
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Structural insights into the recognition of phosphorylated FUNDC1 by LC3B in mitophagy. Protein Cell 2016; 8:25-38. [PMID: 27757847 PMCID: PMC5233613 DOI: 10.1007/s13238-016-0328-8] [Citation(s) in RCA: 89] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Accepted: 09/12/2016] [Indexed: 01/09/2023] Open
Abstract
Mitophagy is an essential intracellular process that eliminates dysfunctional mitochondria and maintains cellular homeostasis. Mitophagy is regulated by the post-translational modification of mitophagy receptors. Fun14 domain-containing protein 1 (FUNDC1) was reported to be a new receptor for hypoxia-induced mitophagy in mammalian cells and interact with microtubule-associated protein light chain 3 beta (LC3B) through its LC3 interaction region (LIR). Moreover, the phosphorylation modification of FUNDC1 affects its binding affinity for LC3B and regulates selective mitophagy. However, the structural basis of this regulation mechanism remains unclear. Here, we present the crystal structure of LC3B in complex with a FUNDC1 LIR peptide phosphorylated at Ser17 (pS17), demonstrating the key residues of LC3B for the specific recognition of the phosphorylated or dephosphorylated FUNDC1. Intriguingly, the side chain of LC3B Lys49 shifts remarkably and forms a hydrogen bond and electrostatic interaction with the phosphate group of FUNDC1 pS17. Alternatively, phosphorylated Tyr18 (pY18) and Ser13 (pS13) in FUNDC1 significantly obstruct their interaction with the hydrophobic pocket and Arg10 of LC3B, respectively. Structural observations are further validated by mutation and isothermal titration calorimetry (ITC) assays. Therefore, our structural and biochemical results reveal a working model for the specific recognition of FUNDC1 by LC3B and imply that the reversible phosphorylation modification of mitophagy receptors may be a switch for selective mitophagy.
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25
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Waliullah TM, Yeasmin AM, Kaneko A, Koike N, Terasawa M, Totsuka T, Ushimaru T. Rim15 and Sch9 kinases are involved in induction of autophagic degradation of ribosomes in budding yeast. Biosci Biotechnol Biochem 2016; 81:307-310. [PMID: 27659307 DOI: 10.1080/09168451.2016.1234928] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Autophagic degradation of ribosomes is promoted by nutrient starvation and inactivation of target of rapamycin complex 1 (TORC1). Here we show that selective autophagic degradation of ribosomes (called ribophagy) after TORC1 inactivation requires the specific autophagy receptor Atg11. Rim15 protein kinase upregulated ribophagy, while it downregulated non-selective degradation of ribosomes.
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Affiliation(s)
| | - Akter Mst Yeasmin
- a Graduate School of Science and Technology , Shizuoka University , Shizuoka , Japan
| | - Atsuki Kaneko
- b Department of Science, Graduate School of Integrated Science and Technology , Shizuoka University , Shizuoka , Japan
| | - Naoki Koike
- b Department of Science, Graduate School of Integrated Science and Technology , Shizuoka University , Shizuoka , Japan
| | - Mashu Terasawa
- c Faculty of Science , Shizuoka University , Shizuoka , Japan
| | - Takaya Totsuka
- c Faculty of Science , Shizuoka University , Shizuoka , Japan
| | - Takashi Ushimaru
- a Graduate School of Science and Technology , Shizuoka University , Shizuoka , Japan.,b Department of Science, Graduate School of Integrated Science and Technology , Shizuoka University , Shizuoka , Japan.,c Faculty of Science , Shizuoka University , Shizuoka , Japan
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26
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Multiple Roles of the Small GTPase Rab7. Cells 2016; 5:cells5030034. [PMID: 27548222 PMCID: PMC5040976 DOI: 10.3390/cells5030034] [Citation(s) in RCA: 267] [Impact Index Per Article: 33.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Revised: 08/11/2016] [Accepted: 08/12/2016] [Indexed: 12/16/2022] Open
Abstract
Rab7 is a small GTPase that belongs to the Rab family and controls transport to late endocytic compartments such as late endosomes and lysosomes. The mechanism of action of Rab7 in the late endocytic pathway has been extensively studied. Rab7 is fundamental for lysosomal biogenesis, positioning and functions, and for trafficking and degradation of several signaling receptors, thus also having implications on signal transduction. Several Rab7 interacting proteins have being identified leading to the discovery of a number of different important functions, beside its established role in endocytosis. Furthermore, Rab7 has specific functions in neurons. This review highlights and discusses the role and the importance of Rab7 on different cellular pathways and processes.
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27
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Kagan VE, Jiang J, Huang Z, Tyurina YY, Desbourdes C, Cottet-Rousselle C, Dar HH, Verma M, Tyurin VA, Kapralov AA, Cheikhi A, Mao G, Stolz D, St. Croix CM, Watkins S, Shen Z, Li Y, Greenberg ML, Tokarska-Schlattner M, Boissan M, Lacombe ML, Epand RM, Chu CT, Mallampalli RK, Bayır H, Schlattner U. NDPK-D (NM23-H4)-mediated externalization of cardiolipin enables elimination of depolarized mitochondria by mitophagy. Cell Death Differ 2016; 23:1140-51. [PMID: 26742431 PMCID: PMC4946882 DOI: 10.1038/cdd.2015.160] [Citation(s) in RCA: 133] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Revised: 10/11/2015] [Accepted: 11/19/2015] [Indexed: 01/16/2023] Open
Abstract
Mitophagy is critical for cell homeostasis. Externalization of the inner mitochondrial membrane phospholipid, cardiolipin (CL), to the surface of the outer mitochondrial membrane (OMM) was identified as a mitophageal signal recognized by the microtubule-associated protein 1 light chain 3. However, the CL-translocating machinery remains unknown. Here we demonstrate that a hexameric intermembrane space protein, NDPK-D (or NM23-H4), binds CL and facilitates its redistribution to the OMM. We found that mitophagy induced by a protonophoric uncoupler, carbonyl cyanide m-chlorophenylhydrazone (CCCP), caused externalization of CL to the surface of mitochondria in murine lung epithelial MLE-12 cells and human cervical adenocarcinoma HeLa cells. RNAi knockdown of endogenous NDPK-D decreased CCCP-induced CL externalization and mitochondrial degradation. A R90D NDPK-D mutant that does not bind CL was inactive in promoting mitophagy. Similarly, rotenone and 6-hydroxydopamine triggered mitophagy in SH-SY5Y cells was also suppressed by knocking down of NDPK-D. In situ proximity ligation assay (PLA) showed that mitophagy-inducing CL-transfer activity of NDPK-D is closely associated with the dynamin-like GTPase OPA1, implicating fission-fusion dynamics in mitophagy regulation.
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Affiliation(s)
- V E Kagan
- Department of Environmental and Occupational Health, Center for Free Radical and Antioxidant Health, University of Pittsburgh, Pittsburgh, PA, USA,Department of Environmental and Occupational Health, Center for Free Radical and Antioxidant Health, University of Pittsburgh, Bridgeside Point, 100 Technology Drive, Suite 350, Pittsburgh, PA 15219, USA. Tel: 412 624 9474; Fax: 412 624 9361; E-mail:
| | - J Jiang
- Department of Environmental and Occupational Health, Center for Free Radical and Antioxidant Health, University of Pittsburgh, Pittsburgh, PA, USA
| | - Z Huang
- Department of Environmental and Occupational Health, Center for Free Radical and Antioxidant Health, University of Pittsburgh, Pittsburgh, PA, USA
| | - Y Y Tyurina
- Department of Environmental and Occupational Health, Center for Free Radical and Antioxidant Health, University of Pittsburgh, Pittsburgh, PA, USA
| | - C Desbourdes
- University Grenoble Alpes—UJF, Laboratory of Fundamental and Applied Bioenergetics (LBFA), and SFR Environmental and Systems Biology (BEeSy), U1055, Grenoble, France,Inserm, U1055, Grenoble, France
| | - C Cottet-Rousselle
- University Grenoble Alpes—UJF, Laboratory of Fundamental and Applied Bioenergetics (LBFA), and SFR Environmental and Systems Biology (BEeSy), U1055, Grenoble, France,Inserm, U1055, Grenoble, France
| | - H H Dar
- Department of Environmental and Occupational Health, Center for Free Radical and Antioxidant Health, University of Pittsburgh, Pittsburgh, PA, USA
| | - M Verma
- Department of Pathology, University of Pittsburgh, Pittsburgh, PA, USA
| | - V A Tyurin
- Department of Environmental and Occupational Health, Center for Free Radical and Antioxidant Health, University of Pittsburgh, Pittsburgh, PA, USA
| | - A A Kapralov
- Department of Environmental and Occupational Health, Center for Free Radical and Antioxidant Health, University of Pittsburgh, Pittsburgh, PA, USA
| | - A Cheikhi
- Department of Environmental and Occupational Health, Center for Free Radical and Antioxidant Health, University of Pittsburgh, Pittsburgh, PA, USA
| | - G Mao
- Department of Environmental and Occupational Health, Center for Free Radical and Antioxidant Health, University of Pittsburgh, Pittsburgh, PA, USA
| | - D Stolz
- Department of Cell Biology and Physiology, University of Pittsburgh, Pittsburgh, PA, USA
| | - C M St. Croix
- Department of Cell Biology and Physiology, University of Pittsburgh, Pittsburgh, PA, USA
| | - S Watkins
- Department of Cell Biology and Physiology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Z Shen
- Department of Biological Sciences, Wayne State University, Detroit, MI, USA
| | - Y Li
- Department of Biological Sciences, Wayne State University, Detroit, MI, USA
| | - M L Greenberg
- Department of Biological Sciences, Wayne State University, Detroit, MI, USA
| | - M Tokarska-Schlattner
- University Grenoble Alpes—UJF, Laboratory of Fundamental and Applied Bioenergetics (LBFA), and SFR Environmental and Systems Biology (BEeSy), U1055, Grenoble, France,Inserm, U1055, Grenoble, France
| | - M Boissan
- Sorbonne Universités, UPMC Univ Paris 06, Saint-Antoine Research Center, INSERM UMR-S 938, Paris, France,AP-HP, Service de Biochimie et Hormonologie, Hôpital Tenon, Paris, France
| | - M-L Lacombe
- Sorbonne Universités, UPMC Univ Paris 06, Saint-Antoine Research Center, INSERM UMR-S 938, Paris, France
| | - R M Epand
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario, Canada
| | - C T Chu
- Department of Pathology, University of Pittsburgh, Pittsburgh, PA, USA
| | - R K Mallampalli
- Department of Medicine, Acute Lung Injury Center of Excellence, University of Pittsburgh, Pittsburgh, PA, USA,Medical Specialty Service Line, Veterans Affairs Pittsburgh Healthcare System, Pittsburgh, PA, USA
| | - H Bayır
- Department of Critical Care Medicine, University of Pittsburgh, Pittsburgh, PA, USA,Department of Critical Care Medicine, University of Pittsburgh, 3434 Fifth Ave, Pittsburgh, PA 15260, USA. Tel: 412 692 5164; Fax: 412 324 0943; E-mail:
| | - U Schlattner
- University Grenoble Alpes—UJF, Laboratory of Fundamental and Applied Bioenergetics (LBFA), and SFR Environmental and Systems Biology (BEeSy), U1055, Grenoble, France,Inserm, U1055, Grenoble, France,University Grenoble Alpes—UJF, Laboratory of Fundamental and Applied Bioenergetics (LBFA), and SFR Environmental and Systems Biology (BEeSy), U1055; BP 53, Grenoble cedex 9, F-38041, France. Tel: +33 476 51 46 71; Fax: +33 476 51 42 18; E-mail:
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28
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Hughes AL, Hughes CE, Henderson KA, Yazvenko N, Gottschling DE. Selective sorting and destruction of mitochondrial membrane proteins in aged yeast. eLife 2016; 5. [PMID: 27097106 PMCID: PMC4889329 DOI: 10.7554/elife.13943] [Citation(s) in RCA: 91] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2015] [Accepted: 04/18/2016] [Indexed: 12/31/2022] Open
Abstract
Mitochondrial dysfunction is a hallmark of aging, and underlies the development of many diseases. Cells maintain mitochondrial homeostasis through a number of pathways that remodel the mitochondrial proteome or alter mitochondrial content during times of stress or metabolic adaptation. Here, using yeast as a model system, we identify a new mitochondrial degradation system that remodels the mitochondrial proteome of aged cells. Unlike many common mitochondrial degradation pathways, this system selectively removes a subset of membrane proteins from the mitochondrial inner and outer membranes, while leaving the remainder of the organelle intact. Selective removal of preexisting proteins is achieved by sorting into a mitochondrial-derived compartment, or MDC, followed by release through mitochondrial fission and elimination by autophagy. Formation of MDCs requires the import receptors Tom70/71, and failure to form these structures exacerbates preexisting mitochondrial dysfunction, suggesting that the MDC pathway provides protection to mitochondria in times of stress.
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Affiliation(s)
- Adam L Hughes
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, United States.,Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, United States
| | - Casey E Hughes
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, United States
| | - Kiersten A Henderson
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, United States
| | - Nina Yazvenko
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, United States
| | - Daniel E Gottschling
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, United States
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29
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Proteasome Impairment Induces Recovery of Mitochondrial Membrane Potential and an Alternative Pathway of Mitochondrial Fusion. Mol Cell Biol 2015; 36:347-62. [PMID: 26552703 DOI: 10.1128/mcb.00920-15] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Accepted: 11/04/2015] [Indexed: 12/18/2022] Open
Abstract
Mitochondria are vital and highly dynamic organelles that continuously fuse and divide to maintain mitochondrial quality. Mitochondrial dysfunction impairs cellular integrity and is known to be associated with various human diseases. However, the mechanism by which the quality of mitochondria is maintained remains largely unexplored. Here we show that impaired proteasome function recovers the growth of yeast cells lacking Fzo1, a pivotal protein for mitochondrial fusion. Decreased proteasome activity increased the mitochondrial oxidoreductase protein Mia40 and the ratio of the short isoform of mitochondrial intermembrane protein Mgm1 (s-Mgm1) to the long isoform (l-Mgm1). The increase in Mia40 restored mitochondrial membrane potential, while the increase in the s-Mgm1/l-Mgm1 ratio promoted mitochondrial fusion in an Fzo1-independent manner. Our findings demonstrate a new pathway for mitochondrial quality control that is induced by proteasome impairment.
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30
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Liu X, Huang Z, Zou X, Yang Y, Qiu Y, Wen Y. Possible mechanism of PNS protection against cisplatin-induced nephrotoxicity in rat models. Toxicol Mech Methods 2015; 25:347-54. [DOI: 10.3109/15376516.2015.1006492] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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31
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Müller M, Lu K, Reichert AS. Mitophagy and mitochondrial dynamics in Saccharomyces cerevisiae. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1853:2766-74. [PMID: 25753536 DOI: 10.1016/j.bbamcr.2015.02.024] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Revised: 02/10/2015] [Accepted: 02/27/2015] [Indexed: 12/13/2022]
Abstract
Mitochondria fulfill central cellular functions including energy metabolism, iron-sulfur biogenesis, and regulation of apoptosis and calcium homeostasis. Accumulation of dysfunctional mitochondria is observed in ageing and many human diseases such as cancer and various neurodegenerative disorders. Appropriate quality control of mitochondria is important for cell survival in most eukaryotic cells. One important pathway in this respect is mitophagy, a selective form of autophagy which removes excess and dysfunctional mitochondria. In the past decades a series of essential factors for mitophagy have been identified and characterized. However, little is known about the molecular mechanisms regulating mitophagy. The role of mitochondrial dynamics in mitophagy is controversially discussed. Here we will review recent advances in this context promoting our understanding on the molecular regulation of mitophagy in Saccharomyces cerevisiae and on the role of mitochondrial dynamics in mitochondrial quality control.
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Affiliation(s)
- Matthias Müller
- Mitochondrial Biology, Buchmann Institute for Molecular Life Sciences, Goethe University Frankfurt am Main, Germany; Mitochondrial Biology, Medical School, Goethe University Frankfurt am Main, Germany
| | - Kaihui Lu
- Institute of Biochemistry and Molecular Biology I, Medical Faculty, Heinrich Heine University, Düsseldorf, Germany
| | - Andreas S Reichert
- Mitochondrial Biology, Buchmann Institute for Molecular Life Sciences, Goethe University Frankfurt am Main, Germany; Mitochondrial Biology, Medical School, Goethe University Frankfurt am Main, Germany; Institute of Biochemistry and Molecular Biology I, Medical Faculty, Heinrich Heine University, Düsseldorf, Germany.
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32
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Müller M, Kötter P, Behrendt C, Walter E, Scheckhuber CQ, Entian KD, Reichert AS. Synthetic quantitative array technology identifies the Ubp3-Bre5 deubiquitinase complex as a negative regulator of mitophagy. Cell Rep 2015; 10:1215-25. [PMID: 25704822 DOI: 10.1016/j.celrep.2015.01.044] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Revised: 12/16/2014] [Accepted: 01/16/2015] [Indexed: 12/18/2022] Open
Abstract
Mitophagy is crucial to ensuring mitochondrial quality control. However, the molecular mechanism and regulation of mitophagy are still not fully understood. Here, we developed a quantitative methodology termed synthetic quantitative array (SQA) technology, which allowed us to perform a genome-wide screen for modulators of rapamycin-induced mitophagy in S. cerevisiae. SQA technology can be easily employed for other enzyme-based reporter systems and widely applied in yeast research. We identified 86 positive and 10 negative regulators of mitophagy. Moreover, SQA-based analysis of non-selective autophagy revealed that 63 of these regulators are specific for mitophagy and 33 regulate autophagy in general. The Ubp3-Bre5 deubiquitination complex was found to inhibit mitophagy but, conversely, to promote other types of autophagy, including ribophagy. This complex translocates dynamically to mitochondria upon induction of mitophagy. These findings point to a role of ubiquitination in mitophagy in yeast and suggest a reciprocal regulation of distinct autophagy pathways.
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Affiliation(s)
- Matthias Müller
- Mitochondrial Biology, Buchmann Institute for Molecular Life Sciences and Zentrum für Molekulare Medizin, Goethe University, Max-von-Laue-Straße 15, 60438 Frankfurt am Main, Germany
| | - Peter Kötter
- Institut für Molekulare Biowissenschaften, Goethe University, Max-von-Laue-Straße 9, 60438 Frankfurt am Main, Germany
| | - Christina Behrendt
- Mitochondrial Biology, Buchmann Institute for Molecular Life Sciences and Zentrum für Molekulare Medizin, Goethe University, Max-von-Laue-Straße 15, 60438 Frankfurt am Main, Germany; Institute of Biochemistry and Molecular Biology I, Medical Faculty, Heinrich Heine University, Universitätsstraße 1, 40225 Düsseldorf, Germany
| | - Elena Walter
- Mitochondrial Biology, Buchmann Institute for Molecular Life Sciences and Zentrum für Molekulare Medizin, Goethe University, Max-von-Laue-Straße 15, 60438 Frankfurt am Main, Germany
| | - Christian Q Scheckhuber
- Mitochondrial Biology, Buchmann Institute for Molecular Life Sciences and Zentrum für Molekulare Medizin, Goethe University, Max-von-Laue-Straße 15, 60438 Frankfurt am Main, Germany
| | - Karl-Dieter Entian
- Institut für Molekulare Biowissenschaften, Goethe University, Max-von-Laue-Straße 9, 60438 Frankfurt am Main, Germany
| | - Andreas S Reichert
- Mitochondrial Biology, Buchmann Institute for Molecular Life Sciences and Zentrum für Molekulare Medizin, Goethe University, Max-von-Laue-Straße 15, 60438 Frankfurt am Main, Germany; Institute of Biochemistry and Molecular Biology I, Medical Faculty, Heinrich Heine University, Universitätsstraße 1, 40225 Düsseldorf, Germany.
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33
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Rohrbach S, Aslam M, Niemann B, Schulz R. Impact of caloric restriction on myocardial ischaemia/reperfusion injury and new therapeutic options to mimic its effects. Br J Pharmacol 2015; 171:2964-92. [PMID: 24611611 DOI: 10.1111/bph.12650] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2013] [Revised: 01/12/2014] [Accepted: 02/10/2014] [Indexed: 12/12/2022] Open
Abstract
Caloric restriction (CR) is the most reliable intervention to extend lifespan and prevent age-related disorders in various species from yeast to rodents. Short- and long-term CR confers cardio protection against ischaemia/reperfusion injury in young and even in aged rodents. A few human trials suggest that CR has the potential to mediate improvement of cardiac or vascular function and induce retardation of cardiac senescence also in humans. The underlying mechanisms are diverse and have not yet been clearly defined. Among the known mediators for the benefits of CR are NO, the AMP-activated PK, sirtuins and adiponectin. Mitochondria, which play a central role in such complex processes within the cell as apoptosis, ATP-production or oxidative stress, are centrally involved in many aspects of CR-induced protection against ischaemic injury. Here, we discuss the relevant literature regarding the protection against myocardial ischaemia/reperfusion injury conferred by CR. Furthermore, we will discuss drug targets to mimic CR and the possible role of calorie restriction in preserving cardiovascular function in humans.
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Affiliation(s)
- Susanne Rohrbach
- Institute of Physiology, Justus Liebig University Giessen, Giessen, Germany
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34
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Maes H, Agostinis P. Autophagy and mitophagy interplay in melanoma progression. Mitochondrion 2014; 19 Pt A:58-68. [PMID: 25042464 DOI: 10.1016/j.mito.2014.07.003] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Revised: 07/02/2014] [Accepted: 07/07/2014] [Indexed: 10/25/2022]
Abstract
Autophagy, or self-eating, is the most extensively studied lysosomal degradation pathway for the recycling of obsolete or damaged cytoplasmic materials, including proteins and organelles. Although this pathway was initially thought to function as trafficking system for 'in bulk' degradation by the lysosomes of cytoplasmic material, it is now widely appreciated that cargo selection by the autophagic machinery is a major process underlying the cytoprotective or--possibly--pro-death functions ascribed to this catabolic process. Indeed increasing evidence suggests that in mammalian cells the removal of dysfunctional or aged mitochondria occurs through a selective degradation pathway known as 'mitophagy'. Due to the crucial role of mitochondria in energy metabolism, redox control and cell survival/death decision, deregulated mitophagy can potentially impact a variety of crucial cell autonomous and non-autonomous processes. Accumulating evidence indicates that during malignant transformation aggressive cancers hijack autophagy to preserve energy fitness and to acquire the plasticity required to adapt to the hostile microenvironment. However, whether and how mitophagy contributes to carcinogenesis, which pathways regulate this process in the cancer cells and how cancer cell-mitophagy impacts and modifies the tumor microenvironment and therapeutic responses, remain largely unanswered issues. In this review, we discuss novel paradigms and pathways regulating mitophagy in mammalian cells and the impact this process might have on one of the most dreadful human malignancies, melanoma.
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Affiliation(s)
- Hannelore Maes
- Laboratory of Cell Death and Therapy, Department Cellular and Molecular Medicine, KU Leuven, Leuven B-3000, Belgium
| | - Patrizia Agostinis
- Laboratory of Cell Death and Therapy, Department Cellular and Molecular Medicine, KU Leuven, Leuven B-3000, Belgium.
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35
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Dynamic regulation of macroautophagy by distinctive ubiquitin-like proteins. Nat Struct Mol Biol 2014; 21:336-45. [PMID: 24699082 DOI: 10.1038/nsmb.2787] [Citation(s) in RCA: 207] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Accepted: 01/10/2014] [Indexed: 12/20/2022]
Abstract
Autophagy complements the ubiquitin-proteasome system in mediating protein turnover. Whereas the proteasome degrades individual proteins modified with ubiquitin chains, autophagy degrades many proteins and organelles en masse. Macromolecules destined for autophagic degradation are 'selected' through sequestration within a specialized double-membrane compartment termed the phagophore, the precursor to an autophagosome, and then are hydrolyzed in a lysosome- or vacuole-dependent manner. Notably, a pair of distinctive ubiquitin-like proteins (UBLs), Atg8 and Atg12, regulate degradation by autophagy in unique ways by controlling autophagosome biogenesis and recruitment of specific cargos during selective autophagy. Here we review structural mechanisms underlying the functions and conjugation of these UBLs that are specialized to provide interaction platforms linked to phagophore membranes.
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36
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A regulatory signaling loop comprising the PGAM5 phosphatase and CK2 controls receptor-mediated mitophagy. Mol Cell 2014; 54:362-77. [PMID: 24746696 DOI: 10.1016/j.molcel.2014.02.034] [Citation(s) in RCA: 398] [Impact Index Per Article: 39.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Revised: 12/13/2013] [Accepted: 02/14/2014] [Indexed: 11/21/2022]
Abstract
Mitochondrial autophagy, or mitophagy, is a major mechanism involved in mitochondrial quality control via selectively removing damaged or unwanted mitochondria. Interactions between LC3 and mitophagy receptors such as FUNDC1, which harbors an LC3-interacting region (LIR), are essential for this selective process. However, how mitochondrial stresses are sensed to activate receptor-mediated mitophagy remains poorly defined. Here, we identify that the mitochondrially localized PGAM5 phosphatase interacts with and dephosphorylates FUNDC1 at serine 13 (Ser-13) upon hypoxia or carbonylcyanide p-trifluoromethoxyphenylhydrazone (FCCP) treatment. Dephosphorylation of FUNDC1 catalyzed by PGAM5 enhances its interaction with LC3, which is abrogated following knockdown of PGAM5 or the introduction of a cell-permeable unphosphorylated peptide encompassing the Ser-13 and LIR of FUNDC1. We further observed that CK2 phosphorylates FUNDC1 to reverse the effect of PGAM5 in mitophagy activation. Our results reveal a mechanistic signaling pathway linking mitochondria-damaging signals to the dephosphorylation of FUNDC1 by PGAM5, which ultimately induces mitophagy.
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Wang Y, Lilley KS, Oliver SG. A protocol for the subcellular fractionation of Saccharomyces cerevisiae using nitrogen cavitation and density gradient centrifugation. Yeast 2014; 31:127-35. [PMID: 24510422 PMCID: PMC4282465 DOI: 10.1002/yea.3002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2013] [Revised: 01/29/2014] [Accepted: 02/01/2014] [Indexed: 11/17/2022] Open
Abstract
Most protocols for yeast subcellular fractionation involve the use of mechanical shear forces to lyse the spheroplasts produced by the enzymatic digestion of the Saccharomyces cerevisiae cell wall. These mechanical homogenization procedures often involve the manual use of devices such as the Dounce homogenizer, and so are very operator-dependent and, in consequence, lack reproducibility. Here, we report a highly reproducible method of homogenizing yeast cells based on nitrogen cavitation. This has been optimized to allow efficient release of subcellular compartments that show a high degree of integrity. The protocol remains effective and reproducible across a range of sample volumes and buffer environments. The subsequent separation method, which employs both sucrose and iodixanol density gradients, has been developed to resolve the major membrane-bound compartments of S. cerevisiae. We present an integrated protocol that is fast, facile, robust and efficient and that will enable ‘omics’ studies of the subcellular compartments of S. cerevisiae and other yeasts.
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Affiliation(s)
- Yuchong Wang
- Cambridge Systems Biology Centre and Department of Biochemistry, University of Cambridge, UK
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Böckler S, Westermann B. Mitochondrial ER contacts are crucial for mitophagy in yeast. Dev Cell 2014; 28:450-8. [PMID: 24530295 DOI: 10.1016/j.devcel.2014.01.012] [Citation(s) in RCA: 164] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2013] [Revised: 12/20/2013] [Accepted: 01/13/2014] [Indexed: 10/25/2022]
Abstract
Damaged and superfluous mitochondria are removed from the cell by selective autophagy, a process termed mitophagy. This serves to maintain the proper quantity and quality of the organelle. Mitophagy is executed by an evolutionarily conserved pathway, many components of which were first discovered and characterized in yeast. In a systematic screen of a yeast deletion collection, we identified ERMES, a complex connecting mitochondria and the endoplasmic reticulum (ER), as an important factor contributing to the selective degradation of mitochondria. We show that efficient mitophagy depends on mitochondrial ER tethering. ERMES colocalizes with sites of mitophagosome biogenesis and affects the formation of the isolation membrane that engulfs the organelles destined for degradation. These results provide insights into the cellular mechanisms that govern organelle homeostasis.
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Affiliation(s)
- Stefan Böckler
- Institut für Zellbiologie, Universität Bayreuth, 95440 Bayreuth, Germany
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Enhancement of ethanol fermentation in Saccharomyces cerevisiae sake yeast by disrupting mitophagy function. Appl Environ Microbiol 2013; 80:1002-12. [PMID: 24271183 DOI: 10.1128/aem.03130-13] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Saccharomyces cerevisiae sake yeast strain Kyokai no. 7 has one of the highest fermentation rates among brewery yeasts used worldwide; therefore, it is assumed that it is not possible to enhance its fermentation rate. However, in this study, we found that fermentation by sake yeast can be enhanced by inhibiting mitophagy. We observed mitophagy in wild-type sake yeast during the brewing of Ginjo sake, but not when the mitophagy gene (ATG32) was disrupted. During sake brewing, the maximum rate of CO2 production and final ethanol concentration generated by the atg32Δ laboratory yeast mutant were 7.50% and 2.12% higher than those of the parent strain, respectively. This mutant exhibited an improved fermentation profile when cultured under limiting nutrient concentrations such as those used during Ginjo sake brewing as well as in minimal synthetic medium. The mutant produced ethanol at a concentration that was 2.76% higher than the parent strain, which has significant implications for industrial bioethanol production. The ethanol yield of the atg32Δ mutant was increased, and its biomass yield was decreased relative to the parent sake yeast strain, indicating that the atg32Δ mutant has acquired a high fermentation capability at the cost of decreasing biomass. Because natural biomass resources often lack sufficient nutrient levels for optimal fermentation, mitophagy may serve as an important target for improving the fermentative capacity of brewery yeasts.
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Campello S, Strappazzon F, Cecconi F. Mitochondrial dismissal in mammals, from protein degradation to mitophagy. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2013; 1837:451-60. [PMID: 24275087 DOI: 10.1016/j.bbabio.2013.11.010] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Revised: 11/06/2013] [Accepted: 11/15/2013] [Indexed: 11/17/2022]
Abstract
Mitochondria are double-membraned highly dynamic organelles; the shape, location and function of which are determined by a constant balance between opposing fusion and fission events. A fine modulation of mitochondrial structure is crucial for their correct functionality and for many physiological cell processes, the status of these organelles, being thus a key aspect in a cell's fate. Indeed, the homeostasis of mitochondria needs to be highly regulated for the above mentioned reasons, and since a) they are the major source of energy; b) they participate in various signaling pathways; albeit at the same time c) they are also the major source of reactive oxygen species (ROS, the main damaging detrimental players for all cell components). Elaborate mechanisms of mitochondrial quality control have evolved for maintaining a functional mitochondrial network and avoiding cell damage. The first mechanism is the removal of damaged mitochondrial proteins within the organelle via chaperones and protease; the second is the cytosolic ubiquitin-proteasome system (UPS), able to eliminate proteins embedded in the outer mitochondrial membrane; the third is the removal of the entire mitochondria through mitophagy, in the case of extensive organelle damage and dysfunction. In this review, we provide an overview of these mitochondria stability and quality control mechanisms, highlighting mitophagy, and emphasizing the central role of mitochondrial dynamics in this context. This article is part of a Special Issue entitled: Dynamic and ultrastructure of bioenergetic membranes and their components.
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Affiliation(s)
| | - Flavie Strappazzon
- IRCCS Fondazione Santa Lucia, 00143 Rome, Italy; Department of Biology, University of Rome Tor Vergata, 00133 Rome, Italy
| | - Francesco Cecconi
- IRCCS Fondazione Santa Lucia, 00143 Rome, Italy; Department of Biology, University of Rome Tor Vergata, 00133 Rome, Italy; Unit of Cell Stress and Survival, Danish Cancer Society Research Center, Strandboulevarden 49, 2100 Copenhagen Ø, Denmark.
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41
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Macromitophagy is a longevity assurance process that in chronologically aging yeast limited in calorie supply sustains functional mitochondria and maintains cellular lipid homeostasis. Aging (Albany NY) 2013; 5:234-69. [PMID: 23553280 PMCID: PMC3651518 DOI: 10.18632/aging.100547] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Macromitophagy controls mitochondrial quality and quantity. It involves the sequestration of dysfunctional or excessive mitochondria within double-membrane autophagosomes, which then fuse with the vacuole/lysosome to deliver these mitochondria for degradation. To investigate a physiological role of macromitophagy in yeast, we examined how theatg32Δ-dependent mutational block of this process influences the chronological lifespan of cells grown in a nutrient-rich medium containing low (0.2%) concentration of glucose. Under these longevity-extending conditions of caloric restriction (CR) yeast cells are not starving. We also assessed a role of macromitophagy in lifespan extension by lithocholic acid (LCA), a bile acid that prolongs yeast longevity under CR conditions. Our findings imply that macromitophagy is a longevity assurance process underlying the synergistic beneficial effects of CR and LCA on yeast lifespan. Our analysis of how the atg32Δ mutation influences mitochondrial morphology, composition and function revealed that macromitophagy is required to maintain a network of healthy mitochondria. Our comparative analysis of the membrane lipidomes of organelles purified from wild-type and atg32Δ cells revealed that macromitophagy is required for maintaining cellular lipid homeostasis. We concluded that macromitophagy defines yeast longevity by modulating vital cellular processes inside and outside of mitochondria.
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Bischof R, Fourtis L, Limbeck A, Gamauf C, Seiboth B, Kubicek CP. Comparative analysis of the Trichoderma reesei transcriptome during growth on the cellulase inducing substrates wheat straw and lactose. BIOTECHNOLOGY FOR BIOFUELS 2013; 6:127. [PMID: 24016404 PMCID: PMC3847502 DOI: 10.1186/1754-6834-6-127] [Citation(s) in RCA: 82] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Accepted: 09/04/2013] [Indexed: 05/05/2023]
Abstract
BACKGROUND Renewable lignocellulosic biomass is an advantageous resource for the production of second generation biofuels and other biorefinery products. In Middle Europe, wheat straw is one of the most abundant low-cost sources of lignocellulosic biomass. For its efficient use, an efficient mix of cellulases and hemicellulases is required. In this paper, we investigated how cellulase production by T. reesei on wheat straw compares to that on lactose, the only soluble and also cheap inducing carbon source for enzyme production. RESULTS We have examined and compared the transcriptome of T. reesei growing on wheat straw and lactose as carbon sources under otherwise similar conditions. Gene expression on wheat straw exceeded that on lactose, and 1619 genes were found to be only induced on wheat straw but not on lactose. They comprised 30% of the CAZome, but were also enriched in genes associated with phospholipid metabolism, DNA synthesis and repair, iron homeostatis and autophagy. Two thirds of the CAZome was expressed both on wheat straw as well as on lactose, but 60% of it at least >2-fold higher on the former. Major wheat straw specific genes comprised xylanases, chitinases and mannosidases. Interestingly, the latter two CAZyme families were significantly higher expressed in a strain in which xyr1 encoding the major regulator of cellulase and hemicellulase biosynthesis is non-functional. CONCLUSIONS Our data reveal several major differences in the transcriptome between wheat straw and lactose which may be related to the higher enzyme formation on the former and their further investigation could lead to the development of methods for increasing enzyme production on lactose.
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Affiliation(s)
- Robert Bischof
- Austrian Centre of Industrial Biotechnology (ACIB) GmBH c/o Institute of Chemical Engineering, University of Technology of Vienna, Gumpendorferstraβe 1a, Vienna A-1060, Austria
| | - Lukas Fourtis
- Institute of Chemical Engineering, University of Technology of Vienna, Gumpendorferstraβe 1a, Vienna A-1060, Austria
| | - Andreas Limbeck
- Institute of Chemical Technologies and Analytics, University of Technology of Vienna, Getreidemarkt 9, Vienna A-1060, Austria
| | - Christian Gamauf
- Biotech & Renewables Center, Clariant GmbH, München 81477, Germany
| | - Bernhard Seiboth
- Austrian Centre of Industrial Biotechnology (ACIB) GmBH c/o Institute of Chemical Engineering, University of Technology of Vienna, Gumpendorferstraβe 1a, Vienna A-1060, Austria
- Institute of Chemical Engineering, University of Technology of Vienna, Gumpendorferstraβe 1a, Vienna A-1060, Austria
| | - Christian P Kubicek
- Austrian Centre of Industrial Biotechnology (ACIB) GmBH c/o Institute of Chemical Engineering, University of Technology of Vienna, Gumpendorferstraβe 1a, Vienna A-1060, Austria
- Institute of Chemical Engineering, University of Technology of Vienna, Gumpendorferstraβe 1a, Vienna A-1060, Austria
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Welter E, Montino M, Reinhold R, Schlotterhose P, Krick R, Dudek J, Rehling P, Thumm M. Uth1 is a mitochondrial inner membrane protein dispensable for post-log-phase and rapamycin-induced mitophagy. FEBS J 2013; 280:4970-82. [PMID: 23910823 DOI: 10.1111/febs.12468] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Revised: 07/01/2013] [Accepted: 07/19/2013] [Indexed: 01/01/2023]
Abstract
Mitochondria are turned over by an autophagic process termed mitophagy. This process is considered to remove damaged, superfluous and aged organelles. However, little is known about how defective organelles are recognized, what types of damage induce turnover, and whether an identical set of factors contributes to degradation under different conditions. Here we systematically compared the mitophagy rate and requirement for mitophagy-specific proteins during post-log-phase and rapamycin-induced mitophagy. To specifically assess mitophagy of damaged mitochondria, we analyzed cells accumulating proteins prone to degradation due to lack of the mitochondrial AAA-protease Yme1. While autophagy 32 (Atg32) was required under all tested conditions, the function of Atg33 could be partially bypassed in post-log-phase and rapamycin-induced mitophagy. Unexpectedly, we found that Uth1 was dispensable for mitophagy. A re-evaluation of its mitochondrial localization revealed that Uth1 is a protein of the inner mitochondrial membrane that is targeted by a cleavable N-terminal pre-sequence. In agreement with our functional analyses, this finding excludes a role of Uth1 as a mitochondrial surface receptor.
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Affiliation(s)
- Evelyn Welter
- Department of Cellular Biochemistry, Georg-August University, Göttingen, Germany
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44
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Guaragnella N, Ždralević M, Lattanzio P, Marzulli D, Pracheil T, Liu Z, Passarella S, Marra E, Giannattasio S. Yeast growth in raffinose results in resistance to acetic-acid induced programmed cell death mostly due to the activation of the mitochondrial retrograde pathway. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1833:2765-2774. [PMID: 23906793 DOI: 10.1016/j.bbamcr.2013.07.017] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2013] [Revised: 06/27/2013] [Accepted: 07/19/2013] [Indexed: 12/22/2022]
Abstract
In order to investigate whether and how a modification of mitochondrial metabolism can affect yeast sensitivity to programmed cell death (PCD) induced by acetic acid (AA-PCD), yeast cells were grown on raffinose, as a sole carbon source, which, differently from glucose, favours mitochondrial respiration. We found that, differently from glucose-grown cells, raffinose-grown cells were mostly resistant to AA-PCD and that this was due to the activation of mitochondrial retrograde (RTG) response, which increased with time, as revealed by the up-regulation of the peroxisomal isoform of citrate synthase and isocitrate dehydrogenase isoform 1, RTG pathway target genes. Accordingly, the deletion of RTG2 and RTG3, a positive regulator and a transcription factor of the RTG pathway, resulted in AA-PCD, as shown by TUNEL assay. Neither deletion in raffinose-grown cells of HAP4, encoding the positive regulatory subunit of the Hap2,3,4,5 complex nor constitutive activation of the RTG pathway in glucose-grown cells due to deletion of MKS1, a negative regulator of RTG pathway, had effect on yeast AA-PCD. The RTG pathway was found to be activated in yeast cells containing mitochondria, in which membrane potential was measured, capable to consume oxygen in a manner stimulated by the uncoupler CCCP and inhibited by the respiratory chain inhibitor antimycin A. AA-PCD resistance in raffinose-grown cells occurs with a decrease in both ROS production and cytochrome c release as compared to glucose-grown cells en route to AA-PCD.
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Affiliation(s)
| | - Maša Ždralević
- CNR, Istituto di Biomembrane e Bioenergetica, Via Amendola 165/a, 70126 Bari, Italy
| | - Paolo Lattanzio
- CNR, Istituto di Biomembrane e Bioenergetica, Via Amendola 165/a, 70126 Bari, Italy
| | - Domenico Marzulli
- CNR, Istituto di Biomembrane e Bioenergetica, Via Amendola 165/a, 70126 Bari, Italy
| | - Tammy Pracheil
- Department of Biological Sciences, University of New Orleans, 2000 Lakeshore Drive, New Orleans, LA 70148, USA
| | - Zhengchang Liu
- Department of Biological Sciences, University of New Orleans, 2000 Lakeshore Drive, New Orleans, LA 70148, USA
| | - Salvatore Passarella
- Dipartimento di Medicina e Scienze per la Salute, Università del Molise, Via de Sanctis, 86100 Campobasso, Italy
| | - Ersilia Marra
- CNR, Istituto di Biomembrane e Bioenergetica, Via Amendola 165/a, 70126 Bari, Italy
| | - Sergio Giannattasio
- CNR, Istituto di Biomembrane e Bioenergetica, Via Amendola 165/a, 70126 Bari, Italy.
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45
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Beach A, Richard VR, Leonov A, Burstein MT, Bourque SD, Koupaki O, Juneau M, Feldman R, Iouk T, Titorenko VI. Mitochondrial membrane lipidome defines yeast longevity. Aging (Albany NY) 2013; 5:551-74. [PMID: 23924582 PMCID: PMC3765583 DOI: 10.18632/aging.100578] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2013] [Accepted: 07/16/2013] [Indexed: 12/22/2022]
Abstract
Our studies revealed that lithocholic acid (LCA), a bile acid, is a potent anti-aging natural compound that in yeast cultured under longevity-extending caloric restriction (CR) conditions acts in synergy with CR to enable a significant further increase in chronological lifespan. Here, we investigate a mechanism underlying this robust longevity-extending effect of LCA under CR. We found that exogenously added LCA enters yeast cells, is sorted to mitochondria, resides mainly in the inner mitochondrial membrane, and also associates with the outer mitochondrial membrane. LCA elicits an age-related remodeling of glycerophospholipid synthesis and movement within both mitochondrial membranes, thereby causing substantial changes in mitochondrial membrane lipidome and triggering major changes in mitochondrial size, number and morphology. In synergy, these changes in the membrane lipidome and morphology of mitochondria alter the age-related chronology of mitochondrial respiration, membrane potential, ATP synthesis and reactive oxygen species homeostasis. The LCA-driven alterations in the age-related dynamics of these vital mitochondrial processes extend yeast longevity. In sum, our findings suggest a mechanism underlying the ability of LCA to delay chronological aging in yeast by accumulating in both mitochondrial membranes and altering their glycerophospholipid compositions. We concluded that mitochondrial membrane lipidome plays an essential role in defining yeast longevity.
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Affiliation(s)
- Adam Beach
- Department of Biology, Concordia University, Montreal, Quebec H4B 1R6, Canada
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46
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Nitsche BM, Burggraaf-van Welzen AM, Lamers G, Meyer V, Ram AFJ. Autophagy promotes survival in aging submerged cultures of the filamentous fungus Aspergillus niger. Appl Microbiol Biotechnol 2013; 97:8205-18. [DOI: 10.1007/s00253-013-4971-1] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2013] [Revised: 04/25/2013] [Accepted: 04/29/2013] [Indexed: 11/29/2022]
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Duan Z, Chen Y, Huang W, Shang Y, Chen P, Wang C. Linkage of autophagy to fungal development, lipid storage and virulence in Metarhizium robertsii. Autophagy 2013; 9:538-49. [PMID: 23380892 DOI: 10.4161/auto.23575] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Autophagy is a highly conserved process that maintains intracellular homeostasis by degrading proteins or organelles in all eukaryotes. The effect of autophagy on fungal biology and infection of insect pathogens is unknown. Here, we report the function of MrATG8, an ortholog of yeast ATG8, in the entomopathogenic fungus Metarhizium robertsii. MrATG8 can complement an ATG8-defective yeast strain and deletion of MrATG8 impaired autophagy, conidiation and fungal infection biology in M. robertsii. Compared with the wild-type and gene-rescued mutant, Mratg8Δ is not inductive to form the infection-structure appressorium and is impaired in defense response against insect immunity. In addition, accumulation of lipid droplets (LDs) is significantly reduced in the conidia of Mratg8Δ and the pathogenicity of the mutant is drastically impaired. We also found that the cellular level of a LD-specific perilipin-like protein is significantly lowered by deletion of MrATG8 and that the carboxyl terminus beyond the predicted protease cleavage site is dispensable for MrAtg8 function. To corroborate the role of autophagy in fungal physiology, the homologous genes of yeast ATG1, ATG4 and ATG15, designated as MrATG1, MrATG4 and MrATG15, were also deleted in M. robertsii. In contrast to Mratg8Δ, these mutants could form appressoria, however, the LD accumulation and virulence were also considerably impaired in the mutant strains. Our data showed that autophagy is required in M. robertsii for fungal differentiation, lipid biogenesis and insect infection. The results advance our understanding of autophagic process in fungi and provide evidence to connect autophagy with lipid metabolism.
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Affiliation(s)
- Zhibing Duan
- Key Laboratory of Insect Developmental and Evolutionary Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
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48
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Mijaljica D, Nazarko TY, Brumell JH, Huang WP, Komatsu M, Prescott M, Simonsen A, Yamamoto A, Zhang H, Klionsky DJ, Devenish RJ. Receptor protein complexes are in control of autophagy. Autophagy 2012; 8:1701-5. [PMID: 22874568 DOI: 10.4161/auto.21332] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
In autophagic processes a variety of cargos is delivered to the degradative compartment of cells. Recent progress in autophagy research has provided support for the notion that when autophagic processes are operating in selective mode, a receptor protein complex will process the cargo. Here we present a concept of receptor protein complexes as comprising a functional tetrad of components: a ligand, a receptor, a scaffold and an Atg8 family protein. Our current understanding of each of the four components and their interaction in the context of cargo selection are considered in turn.
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Affiliation(s)
- Dalibor Mijaljica
- Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Faculty of Medicine, Nursing and Health Sciences, Monash University Clayton Campus, Victoria, Australia
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49
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Nitsche BM, Jørgensen TR, Akeroyd M, Meyer V, Ram AFJ. The carbon starvation response of Aspergillus niger during submerged cultivation: insights from the transcriptome and secretome. BMC Genomics 2012; 13:380. [PMID: 22873931 PMCID: PMC3527191 DOI: 10.1186/1471-2164-13-380] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2012] [Accepted: 07/26/2012] [Indexed: 01/13/2023] Open
Abstract
Background Filamentous fungi are confronted with changes and limitations of their carbon source during growth in their natural habitats and during industrial applications. To survive life-threatening starvation conditions, carbon from endogenous resources becomes mobilized to fuel maintenance and self-propagation. Key to understand the underlying cellular processes is the system-wide analysis of fungal starvation responses in a temporal and spatial resolution. The knowledge deduced is important for the development of optimized industrial production processes. Results This study describes the physiological, morphological and genome-wide transcriptional changes caused by prolonged carbon starvation during submerged batch cultivation of the filamentous fungus Aspergillus niger. Bioreactor cultivation supported highly reproducible growth conditions and monitoring of physiological parameters. Changes in hyphal growth and morphology were analyzed at distinct cultivation phases using automated image analysis. The Affymetrix GeneChip platform was used to establish genome-wide transcriptional profiles for three selected time points during prolonged carbon starvation. Compared to the exponential growth transcriptome, about 50% (7,292) of all genes displayed differential gene expression during at least one of the starvation time points. Enrichment analysis of Gene Ontology, Pfam domain and KEGG pathway annotations uncovered autophagy and asexual reproduction as major global transcriptional trends. Induced transcription of genes encoding hydrolytic enzymes was accompanied by increased secretion of hydrolases including chitinases, glucanases, proteases and phospholipases as identified by mass spectrometry. Conclusions This study is the first system-wide analysis of the carbon starvation response in a filamentous fungus. Morphological, transcriptomic and secretomic analyses identified key events important for fungal survival and their chronology. The dataset obtained forms a comprehensive framework for further elucidation of the interrelation and interplay of the individual cellular events involved.
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Affiliation(s)
- Benjamin M Nitsche
- Institute of Biology Leiden, Molecular Microbiology and Biotechnology, Leiden University, Sylviusweg 72, 2333 BE Leiden, The Netherlands.
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50
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Nakatogawa H, Ohbayashi S, Sakoh-Nakatogawa M, Kakuta S, Suzuki SW, Kirisako H, Kondo-Kakuta C, Noda NN, Yamamoto H, Ohsumi Y. The autophagy-related protein kinase Atg1 interacts with the ubiquitin-like protein Atg8 via the Atg8 family interacting motif to facilitate autophagosome formation. J Biol Chem 2012; 287:28503-7. [PMID: 22778255 DOI: 10.1074/jbc.c112.387514] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
In autophagy, a cup-shaped membrane called the isolation membrane is formed, expanded, and sealed to complete a double membrane-bound vesicle called the autophagosome that encapsulates cellular constituents to be transported to and degraded in the lysosome/vacuole. The formation of the autophagosome requires autophagy-related (Atg) proteins. Atg8 is a ubiquitin-like protein that localizes to the isolation membrane; a subpopulation of this protein remains inside the autophagosome and is transported to the lysosome/vacuole. In the budding yeast Saccharomyces cerevisiae, Atg1 is a serine/threonine kinase that functions in the initial step of autophagosome formation and is also efficiently transported to the vacuole via autophagy. Here, we explore the mechanism and significance of this autophagic transport of Atg1. In selective types of autophagy, receptor proteins recognize degradation targets and also interact with Atg8, via the Atg8 family interacting motif (AIM), to link the targets to the isolation membrane. We find that Atg1 contains an AIM and directly interacts with Atg8. Mutations in the AIM disrupt this interaction and abolish vacuolar transport of Atg1. These results suggest that Atg1 associates with the isolation membrane by binding to Atg8, resulting in its incorporation into the autophagosome. We also show that mutations in the Atg1 AIM cause a significant defect in autophagy, without affecting the functions of Atg1 implicated in triggering autophagosome formation. We propose that in addition to its essential function in the initial stage, Atg1 also associates with the isolation membrane to promote its maturation into the autophagosome.
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Affiliation(s)
- Hitoshi Nakatogawa
- Frontier Research Center, Tokyo Institute of Technology, Yokohama 226-8503, Japan.
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