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Knight K, Park JB, Oot RA, Khan MM, Roh SH, Wilkens S. Monoclonal nanobodies alter the activity and assembly of the yeast vacuolar H +-ATPase. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2025:2025.01.10.632502. [PMID: 39829782 PMCID: PMC11741422 DOI: 10.1101/2025.01.10.632502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 01/22/2025]
Abstract
The vacuolar ATPase (V-ATPase; V1Vo) is a multi-subunit rotary nanomotor proton pump that acidifies organelles in virtually all eukaryotic cells, and extracellular spaces in some specialized tissues of higher organisms. Evidence suggests that metastatic breast cancers mislocalize V-ATPase to the plasma membrane to promote cell survival and facilitate metastasis, making the V-ATPase a potential drug target. We have generated a library of camelid single-domain antibodies (Nanobodies; Nbs) against lipid-nanodisc reconstituted yeast V-ATPase Vo proton channel subcomplex. Here, we present an in-depth characterization of three anti-Vo Nbs using biochemical and biophysical in vitro experiments. We find that the Nbs bind Vo with high affinity, with one Nb inhibiting holoenzyme activity and another one preventing enzyme assembly. Using cryoEM, we find that two of the Nbs bind the c subunit ring of the Vo on the lumen side of the complex. Additionally, we show that one of the Nbs raised against yeast Vo can pull down human V-ATPase (HsV1Vo). Our research demonstrates Nb versatility to target and modulate the activity of the V-ATPase, and highlights the potential for future therapeutic Nb development.
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Affiliation(s)
- Kassidy Knight
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY 13210, USA
| | - Jun Bae Park
- Department of Biological Sciences, Seoul National University, Seoul, Korea
- Present address: Department of Cancer Biology, Lerner research Institute, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Rebecca A. Oot
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY 13210, USA
| | - Md. Murad Khan
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY 13210, USA
- Present address: Howard Hughes Medical Institute, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Soung-Hun Roh
- Department of Biological Sciences, Seoul National University, Seoul, Korea
| | - Stephan Wilkens
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY 13210, USA
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2
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Kim Y. Fisetin-Mediated Perturbations of Membrane Permeability and Intracellular pH in Candida albicans. J Microbiol Biotechnol 2024; 34:783-794. [PMID: 38213272 PMCID: PMC11091701 DOI: 10.4014/jmb.2311.11027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Revised: 12/26/2023] [Accepted: 12/29/2023] [Indexed: 01/13/2024]
Abstract
The antifungal activity of fisetin against Candida albicans is explored, elucidating a mechanism centered on membrane permeabilization and ensuing disruption of pH homeostasis. The Minimum Inhibitory Concentration (MIC) of fisetin, indicative of its interaction with the fungal membrane, increases in the presence of ergosterol. Hoechst 33342 and propidium-iodide staining reveal substantial propidium-iodide accumulation in fisetin-treated C. albicans cells at their MIC, with crystal violet uptake assays confirming fisetin-induced membrane permeabilization. Leakage analysis demonstrates a significant release of DNA and proteins in fisetin-treated cells compared to controls, underscoring the antifungal effect through membrane disruption. Green fluorescence, evident in both the cytoplasm and vacuoles of fisetin-treated cells under BCECF, AM staining, stands in contrast to controls where only acidic vacuoles exhibit staining. Ratiometric pH measurements using BCECF, AM reveal a noteworthy reduction in intracellular pH in fisetin-treated cells, emphasizing its impact on pH homeostasis. DiBAC4(3) uptake assays demonstrate membrane hyperpolarization in fisetin-treated cells, suggesting potential disruptions in ion flux and cellular homeostasis. These results provide comprehensive insights into the antifungal mechanisms of fisetin, positioning it as a promising therapeutic agent against Candida infections.
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Affiliation(s)
- Younhee Kim
- Department of Korean Medicine, Semyung University, Jecheon 27136, Republic of Korea
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3
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Yuan W, Lin H, Sun Y, Liu L, Yan M, Song Y, Zhang X, Lu X, Xu Y, He Q, Ouyang K, Zhang C, Pan Y, Huang Y, Li Y, Lu X, Liu J. Myocardin reverses insulin resistance and ameliorates cardiomyopathy by increasing IRS-1 expression in a murine model of lipodystrophy caused by adipose deficiency of vacuolar H +-ATPase V0d1 subunit. Theranostics 2024; 14:2246-2264. [PMID: 38505620 PMCID: PMC10945344 DOI: 10.7150/thno.93192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Accepted: 03/02/2024] [Indexed: 03/21/2024] Open
Abstract
Aim: Adipose tissue (AT) dysfunction that occurs in both obesity and lipodystrophy is associated with the development of cardiomyopathy. However, it is unclear how dysfunctional AT induces cardiomyopathy due to limited animal models available. We have identified vacuolar H+-ATPase subunit Vod1, encoded by Atp6v0d1, as a master regulator of adipogenesis, and adipose-specific deletion of Atp6v0d1 (Atp6v0d1AKO) in mice caused generalized lipodystrophy and spontaneous cardiomyopathy. Using this unique animal model, we explore the mechanism(s) underlying lipodystrophy-related cardiomyopathy. Methods and Results: Atp6v0d1AKO mice developed cardiac hypertrophy at 12 weeks, and progressed to heart failure at 28 weeks. The Atp6v0d1AKO mouse hearts exhibited excessive lipid accumulation and altered lipid and glucose metabolism, which are typical for obesity- and diabetes-related cardiomyopathy. The Atp6v0d1AKO mice developed cardiac insulin resistance evidenced by decreased IRS-1/2 expression in hearts. Meanwhile, the expression of forkhead box O1 (FoxO1), a transcription factor which plays critical roles in regulating cardiac lipid and glucose metabolism, was increased. RNA-seq data and molecular biological assays demonstrated reduced expression of myocardin, a transcription coactivator, in Atp6v0d1AKO mouse hearts. RNA interference (RNAi), luciferase reporter and ChIP-qPCR assays revealed the critical role of myocardin in regulating IRS-1 transcription through the CArG-like element in IRS-1 promoter. Reducing IRS-1 expression with RNAi increased FoxO1 expression, while increasing IRS-1 expression reversed myocardin downregulation-induced FoxO1 upregulation in cardiomyocytes. In vivo, restoring myocardin expression specifically in Atp6v0d1AKO cardiomyocytes increased IRS-1, but decreased FoxO1 expression. As a result, the abnormal expressions of metabolic genes in Atp6v0d1AKO hearts were reversed, and cardiac dysfunctions were ameliorated. Myocardin expression was also reduced in high fat diet-induced diabetic cardiomyopathy and palmitic acid-treated cardiomyocytes. Moreover, increasing systemic insulin resistance with rosiglitazone restored cardiac myocardin expression and improved cardiac functions in Atp6v0d1AKO mice. Conclusion: Atp6v0d1AKO mice are a novel animal model for studying lipodystrophy- or metabolic dysfunction-related cardiomyopathy. Moreover, myocardin serves as a key regulator of cardiac insulin sensitivity and metabolic homeostasis, highlighting myocardin as a potential therapeutic target for treating lipodystrophy- and diabetes-related cardiomyopathy.
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Affiliation(s)
- Wenlin Yuan
- Department of pathophysiology, Shenzhen University Medical School, Shenzhen University, Shenzhen, China
| | - Hui Lin
- Clinical Research Center, The First Affiliated Hospital of Shantou University Medical College, Shantou, China
- Division of Pharmacology and Vascular Medicine, Department of Internal Medicine, Erasmus Medical Center, Rotterdam, the Netherlands
| | - Yuan Sun
- Clinical Research Center, The First Affiliated Hospital of Shantou University Medical College, Shantou, China
- Department of Pharmacology, College of Pharmacy, Shenzhen Technology University, Shenzhen, China
| | - Lihuan Liu
- Department of pathophysiology, Shenzhen University Medical School, Shenzhen University, Shenzhen, China
| | - Meijuan Yan
- Department of pathophysiology, Shenzhen University Medical School, Shenzhen University, Shenzhen, China
| | - Yujuan Song
- Department of pathophysiology, Shenzhen University Medical School, Shenzhen University, Shenzhen, China
| | - Xiaofan Zhang
- Department of pathophysiology, Shenzhen University Medical School, Shenzhen University, Shenzhen, China
| | - Xiangling Lu
- Department of pathophysiology, Shenzhen University Medical School, Shenzhen University, Shenzhen, China
| | - Yipei Xu
- Department of pathophysiology, Shenzhen University Medical School, Shenzhen University, Shenzhen, China
| | - Qiyue He
- Department of pathophysiology, Shenzhen University Medical School, Shenzhen University, Shenzhen, China
| | - Kunfu Ouyang
- Department of Cardiovascular Surgery, Peking University Shenzhen Hospital, Shenzhen, China
| | - Chenglin Zhang
- Department of pathophysiology, Shenzhen University Medical School, Shenzhen University, Shenzhen, China
| | - Yong Pan
- Department of pathophysiology, Shenzhen University Medical School, Shenzhen University, Shenzhen, China
| | - Yu Huang
- Department of Biomedical Sciences, City University of Hong Kong, Hong Kong, China
| | - Ying Li
- Department of pathophysiology, Shenzhen University Medical School, Shenzhen University, Shenzhen, China
| | - Xifeng Lu
- Department of pathophysiology, Shenzhen University Medical School, Shenzhen University, Shenzhen, China
- Clinical Research Center, The First Affiliated Hospital of Shantou University Medical College, Shantou, China
- Division of Pharmacology and Vascular Medicine, Department of Internal Medicine, Erasmus Medical Center, Rotterdam, the Netherlands
- Department of Pharmacology, Shantou University Medical College, Shantou, China
| | - Jie Liu
- Department of pathophysiology, Shenzhen University Medical School, Shenzhen University, Shenzhen, China
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4
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Antunes M, Sá-Correia I. The role of ion homeostasis in adaptation and tolerance to acetic acid stress in yeasts. FEMS Yeast Res 2024; 24:foae016. [PMID: 38658183 PMCID: PMC11092280 DOI: 10.1093/femsyr/foae016] [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: 03/19/2024] [Revised: 04/16/2024] [Accepted: 04/23/2024] [Indexed: 04/26/2024] Open
Abstract
Maintenance of asymmetric ion concentrations across cellular membranes is crucial for proper yeast cellular function. Disruptions of these ionic gradients can significantly impact membrane electrochemical potential and the balance of other ions, particularly under stressful conditions such as exposure to acetic acid. This weak acid, ubiquitous to both yeast metabolism and industrial processes, is a major inhibitor of yeast cell growth in industrial settings and a key determinant of host colonization by pathogenic yeast. Acetic acid toxicity depends on medium composition, especially on the pH (H+ concentration), but also on other ions' concentrations. Regulation of ion fluxes is essential for effective yeast response and adaptation to acetic acid stress. However, the intricate interplay among ion balancing systems and stress response mechanisms still presents significant knowledge gaps. This review offers a comprehensive overview of the mechanisms governing ion homeostasis, including H+, K+, Zn2+, Fe2+/3+, and acetate, in the context of acetic acid toxicity, adaptation, and tolerance. While focus is given on Saccharomyces cerevisiae due to its extensive physiological characterization, insights are also provided for biotechnologically and clinically relevant yeast species whenever available.
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Affiliation(s)
- Miguel Antunes
- iBB—Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, 1049-001, Lisbon, Portugal
- Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, 1049-001, Lisbon, Portugal
- Associate Laboratory i4HB—Institute for Health and Bioeconomy at Instituto Superior Técnico, Universidade de Lisboa, 1049-001, Lisbon, Portugal
| | - Isabel Sá-Correia
- iBB—Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, 1049-001, Lisbon, Portugal
- Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, 1049-001, Lisbon, Portugal
- Associate Laboratory i4HB—Institute for Health and Bioeconomy at Instituto Superior Técnico, Universidade de Lisboa, 1049-001, Lisbon, Portugal
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5
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Yang SZ, Peng LT. Significance of the plasma membrane H +-ATPase and V-ATPase for growth and pathogenicity in pathogenic fungi. ADVANCES IN APPLIED MICROBIOLOGY 2023; 124:31-53. [PMID: 37597947 DOI: 10.1016/bs.aambs.2023.07.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/21/2023]
Abstract
Pathogenic fungi are widespread and cause a variety of diseases in human beings and other organisms. At present, limited classes of antifungal agents are available to treat invasive fungal diseases. With the wide use of the commercial antifungal agents, drug resistance of pathogenic fungi are continuously increasing. Therefore, exploring effective antifungal agents with novel drug targets is urgently needed to cope with the challenges that the antifungal area faces. pH homeostasis is vital for multiple cellular processes, revealing the potential for defining novel drug targets. Fungi have evolved a number of strategies to maintain a stable pH internal environment in response to rapid metabolism and a dramatically changing extracellular environment. Among them, plasma membrane H+-ATPase (PMA) and vacuolar H+-ATPase (V-ATPase) play a central role in the regulation of pH homeostasis system. In this chapter, we will summarize the current knowledge about pH homeostasis and its regulation mechanisms in pathogenic fungi, especially for the recent advances in PMA and V-ATPase, which would help in revealing the regulating mechanism of pH on cell growth and pathogenicity, and further designing effective drugs and identify new targets for combating fungal diseases.
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Affiliation(s)
- S Z Yang
- Key Laboratory of Environment Correlative Dietology, Ministry of Education, College of Food Science and Technology, Huazhong Agricultural University, Wuhan, P.R. China.
| | - L T Peng
- Key Laboratory of Environment Correlative Dietology, Ministry of Education, College of Food Science and Technology, Huazhong Agricultural University, Wuhan, P.R. China
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6
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Tuli F, Kane PM. The cytosolic N-terminal domain of V-ATPase a-subunits is a regulatory hub targeted by multiple signals. Front Mol Biosci 2023; 10:1168680. [PMID: 37398550 PMCID: PMC10313074 DOI: 10.3389/fmolb.2023.1168680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Accepted: 06/05/2023] [Indexed: 07/04/2023] Open
Abstract
Vacuolar H+-ATPases (V-ATPases) acidify several organelles in all eukaryotic cells and export protons across the plasma membrane in a subset of cell types. V-ATPases are multisubunit enzymes consisting of a peripheral subcomplex, V1, that is exposed to the cytosol and an integral membrane subcomplex, Vo, that contains the proton pore. The Vo a-subunit is the largest membrane subunit and consists of two domains. The N-terminal domain of the a-subunit (aNT) interacts with several V1 and Vo subunits and serves to bridge the V1 and Vo subcomplexes, while the C-terminal domain contains eight transmembrane helices, two of which are directly involved in proton transport. Although there can be multiple isoforms of several V-ATPase subunits, the a-subunit is encoded by the largest number of isoforms in most organisms. For example, the human genome encodes four a-subunit isoforms that exhibit a tissue- and organelle-specific distribution. In the yeast S. cerevisiae, the two a-subunit isoforms, Golgi-enriched Stv1 and vacuolar Vph1, are the only V-ATPase subunit isoforms. Current structural information indicates that a-subunit isoforms adopt a similar backbone structure but sequence variations allow for specific interactions during trafficking and in response to cellular signals. V-ATPases are subject to several types of environmental regulation that serve to tune their activity to their cellular location and environmental demands. The position of the aNT domain in the complex makes it an ideal target for modulating V1-Vo interactions and regulating enzyme activity. The yeast a-subunit isoforms have served as a paradigm for dissecting interactions of regulatory inputs with subunit isoforms. Importantly, structures of yeast V-ATPases containing each a-subunit isoform are available. Chimeric a-subunits combining elements of Stv1NT and Vph1NT have provided insights into how regulatory inputs can be integrated to allow V-ATPases to support cell growth under different stress conditions. Although the function and distribution of the four mammalian a-subunit isoforms present additional complexity, it is clear that the aNT domains of these isoforms are also subject to multiple regulatory interactions. Regulatory mechanisms that target mammalian a-subunit isoforms, and specifically the aNT domains, will be described. Altered V-ATPase function is associated with multiple diseases in humans. The possibility of regulating V-ATPase subpopulations via their isoform-specific regulatory interactions are discussed.
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Affiliation(s)
| | - Patricia M. Kane
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, United States
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7
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Tuli F, Kane PM. Chimeric a-subunit isoforms generate functional yeast V-ATPases with altered regulatory properties in vitro and in vivo. Mol Biol Cell 2023; 34:ar14. [PMID: 36598799 PMCID: PMC10011726 DOI: 10.1091/mbc.e22-07-0265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
V-ATPases are highly regulated proton pumps that acidify organelles. The V-ATPase a-subunit is a two-domain protein containing a C-terminal transmembrane domain responsible for proton transport and an N-terminal cytosolic domain (aNT) that is a regulatory hub, integrating environmental inputs to regulate assembly, localization, and V-ATPase activity. The yeast Saccharomyces cerevisiae encodes only two organelle-specific a-isoforms, Stv1 in the Golgi and Vph1 in the vacuole. On the basis of recent structures, we designed chimeric yeast aNTs in which the globular proximal and distal ends are exchanged. The Vph1 proximal-Stv1 distal (VPSD) aNT chimera binds to the glucose-responsive RAVE assembly factor in vitro but exhibits little binding to PI(3,5)P2. The Stv1 proximal-Vph1 distal (SPVD) aNT lacks RAVE binding but binds more tightly to phosphoinositides than Vph1 or Stv1. When attached to the Vph1 C-terminal domain in vivo, both chimeras complement growth defects of a vph1∆ mutant, but only the SPVD chimera exhibits wild-type V-ATPase activity. Cells containing the SPVD chimera adapt more slowly to a poor carbon source than wild-type cells but grow more rapidly than wild-type cells after a shift to alkaline pH. This is the first example of a "redesigned" V-ATPase with altered regulatory properties and adaptation to specific stresses.
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Affiliation(s)
- Farzana Tuli
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY 13210
| | - Patricia M Kane
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY 13210
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8
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Omar AH, Hajissa K, Bashir JQ, Omar AS, Faris AA, Nurhidanatasha AB. A Postulated Mechanism of the Antimalarial Effect of Free Radicals Generated by Artemisinin on Plasmodium falciparum. BIOMEDICAL AND PHARMACOLOGY JOURNAL 2022; 15:1833-1836. [DOI: 10.13005/bpj/2521] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2025]
Abstract
Artemisinin and its derivatives, a class of antimalarial drugs, were first isolated from Artemisia annua. Artemisinin can alter the pH of the malaria parasite’s digestive vacuole from acidic to alkaline, leading to parasite death. However, the precise mechanism of artemisinin action in changing the digestive vacuole pH has not yet been confirmed. Previous studies reported that artemisinin and its derivatives could kill the parasites through the generation of oxidative stress by the free radicals they generate. This review aims to provide a better understanding of the possible mechanism of action of artemisinin, focusing on the antimalarial activity caused by the generated free radicals through the induction of mutation in the genes that encode the proton pump of the Plasmodium falciparum digestive vacuole.
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Affiliation(s)
- Alfaqih Hussain Omar
- 1Biomedicine Programme, School of Health Sciences, Health Campus, Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan, Malaysia
| | - Khalid Hajissa
- 2Department of Medical Microbiology and Parasitology, School of Medical Sciences, Health Campus, Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan, Malaysia
| | - Jarrar Qais Bashir
- 3Department of Pharmaceutical Science, Faculty of Pharmacy, Al-Isra’a University, Amman, Jordan
| | - Alfaqih Sirin Omar
- 4Department of Internal Medicine, Al Noor Specialist Hospital, Mecca 20424, Saudi Arabia
| | - Aldoghachi Ahmed Faris
- 5Faculty of Medicine and Health Sciences, Universiti Tunku Abdul Rahman, Cheras, 43000 Kajang, Selangor, Malaysia
| | - Abu Bakar Nurhidanatasha
- 1Biomedicine Programme, School of Health Sciences, Health Campus, Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan, Malaysia
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9
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Sun C, Li X, Zhang Y, Lu L. Subunit C of V-ATPase-VmaC Is Required for Hyphal Growth and Conidiation in A. fumigatus by Affecting Vacuolar Calcium Homeostasis and Cell Wall Integration. J Fungi (Basel) 2022; 8:1219. [PMID: 36422040 PMCID: PMC9699406 DOI: 10.3390/jof8111219] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2022] [Revised: 11/14/2022] [Accepted: 11/15/2022] [Indexed: 08/21/2023] Open
Abstract
Aspergillus fumigatus is a widespread airborne fungal pathogen in humans. However, the functional genes in A. fumigatus that may contribute to its pathogenesis have not yet been fully identified. Vacuolar H+-ATPase is universal in eukaryotic organisms but exhibits specific roles in various species. Here, we identified VmaC as a putative subunit of vacuolar H+-ATPase in A. fumigatus that is widely conserved through evolution. The C-terminal hydrophobic domain of VmaC plays a critical role in its vacuolar localization and growth and conidiation. Deletion or turn-off of VmaC encoding gene-AfvmaC expression is not lethal but leads to a very sick and tiny colony phenotype, which is different from that of yeast with conditional ScvmaC defects. Furthermore, we found that AfvmaC not only participates in maintaining calcium homeostasis and vacuolar acidity but is also involved in cell wall integration pathway regulation, highlighting the importance of the vacuole as a storage organelle associated with many aspects of cellular homeostasis. This study indicates that fungal VmaC is relatively conserved. When compared to that in model yeasts, VmaC in A. fumigatus is required for hyphal growth and conidiation, suggesting that specific motifs in VmaC might be functioned in Aspergilli.
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Affiliation(s)
| | | | - Yuanwei Zhang
- Jiangsu Key Laboratory for Microbes and Functional Genomics, College of Life Sciences, Nanjing Normal University, Nanjing 210023, China
| | - Ling Lu
- Jiangsu Key Laboratory for Microbes and Functional Genomics, College of Life Sciences, Nanjing Normal University, Nanjing 210023, China
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10
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Su K, Collins MP, McGuire CM, Alshagawi MA, Alamoudi MK, Li Z, Forgac M. Isoform a4 of the vacuolar ATPase a subunit promotes 4T1-12B breast cancer cell-dependent tumor growth and metastasis in vivo. J Biol Chem 2022; 298:102395. [PMID: 35988642 PMCID: PMC9508560 DOI: 10.1016/j.jbc.2022.102395] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Revised: 08/11/2022] [Accepted: 08/15/2022] [Indexed: 12/24/2022] Open
Abstract
The vacuolar H+-ATPase (V-ATPase) is an ATP-dependent proton pump that governs the pH of various intracellular compartments and also functions at the plasma membrane in certain cell types, including cancer cells. Membrane targeting of the V-ATPase is controlled by isoforms of subunit a, and we have previously shown that isoforms a3 and a4 are important for the migration and invasion of several breast cancer cell lines in vitro. Using CRISPR-mediated genome editing to selectively disrupt each of the four a subunit isoforms, we also recently showed that a4 is critical to plasma membrane V-ATPase localization, as well as in vitro migration and invasion of 4T1-12B murine breast cancer cells. We now report that a4 is important for the growth of 4T1-12B tumors in vivo. We found that BALB/c mice bearing a4-/- 4T1-12B allografts had significantly smaller tumors than mice in the control group. In addition, we determined that a4-/- allografts showed dramatically reduced metastases to the lung and reduced luminescence intensity of metastases to bone relative to the control group. Taken together, these results suggest that the a4 isoform of the V-ATPase represents a novel potential therapeutic target to limit breast cancer growth and metastasis.
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Affiliation(s)
- Kevin Su
- Department of Pharmacology and Drug Development, Graduate School of Biomedical Sciences, Tufts University, Boston, Massachusetts, USA
| | - Michael P Collins
- Department of Cellular, Molecular and Developmental Biology, Graduate School of Biomedical Sciences, Tufts University, Boston, Massachusetts, USA
| | - Christina M McGuire
- Department of Biochemistry, Graduate School of Biomedical Sciences, Tufts University, Boston, Massachusetts, USA
| | - Mohammed A Alshagawi
- Department of Pharmacology and Drug Development, Graduate School of Biomedical Sciences, Tufts University, Boston, Massachusetts, USA
| | - Mariam K Alamoudi
- Department of Developmental, Molecular, and Chemical Biology, Tufts University School of Medicine, Boston, Massachusetts, USA
| | - Zhen Li
- Department of Pharmacology and Drug Development, Graduate School of Biomedical Sciences, Tufts University, Boston, Massachusetts, USA
| | - Michael Forgac
- Department of Pharmacology and Drug Development, Graduate School of Biomedical Sciences, Tufts University, Boston, Massachusetts, USA; Department of Cellular, Molecular and Developmental Biology, Graduate School of Biomedical Sciences, Tufts University, Boston, Massachusetts, USA; Department of Biochemistry, Graduate School of Biomedical Sciences, Tufts University, Boston, Massachusetts, USA; Department of Developmental, Molecular, and Chemical Biology, Tufts University School of Medicine, Boston, Massachusetts, USA.
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11
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Structure of V-ATPase from citrus fruit. Structure 2022; 30:1403-1410.e4. [PMID: 36041457 DOI: 10.1016/j.str.2022.07.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Revised: 06/14/2022] [Accepted: 07/18/2022] [Indexed: 11/23/2022]
Abstract
We used the Legionella pneumophila effector SidK to affinity purify the endogenous vacuolar-type ATPases (V-ATPases) from lemon fruit. The preparation was sufficient for cryoelectron microscopy, allowing structure determination of the enzyme in two rotational states. The structure defines the ATP:H+ ratio of the enzyme, demonstrating that it can establish a maximum ΔpH of ∼3, which is insufficient to maintain the low pH observed in the vacuoles of juice sac cells in lemons and other citrus fruit. Compared with yeast and mammalian enzymes, the membrane region of the plant V-ATPase lacks subunit f and possesses an unusual configuration of transmembrane α helices. Subunit H, which inhibits ATP hydrolysis in the isolated catalytic region of V-ATPase, adopts two different conformations in the intact complex, hinting at a role in modulating activity in the intact enzyme.
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12
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Hans S, Fatima Z, Ahmad A, Hameed S. Magnesium impairs Candida albicans immune evasion by reduced hyphal damage, enhanced β-glucan exposure and altered vacuole homeostasis. PLoS One 2022; 17:e0270676. [PMID: 35834579 PMCID: PMC9282612 DOI: 10.1371/journal.pone.0270676] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Accepted: 06/14/2022] [Indexed: 11/18/2022] Open
Abstract
With a limited arsenal of available antifungal drugs and drug-resistance emergence, strategies that seek to reduce Candida immune evasion and virulence could be a promising alternative option. Harnessing metal homeostasis against C. albicans has gained wide prominence nowadays as a feasible antifungal strategy. Herein, the effect of magnesium (Mg) deprivation on the immune evasion mechanisms of C. albicans is demonstrated. We studied host pathogen interaction by using the THP-1 cell line model and explored the avenue that macrophage-mediated killing was enhanced under Mg deprivation, leading to altered cytokine (TNFα, IL-6 and IL10) production and reduced pyroptosis. Insights into the mechanisms revealed that hyphal damage inside the macrophage was diminished under Mg deprivation. Additionally, Mg deprivation led to cell wall remodelling; leading to enhanced β-1,3-glucan exposure, crucial for immune recognition, along with concomitant alterations in chitin and mannan levels. Furthermore, vacuole homeostasis was disrupted under Mg deprivation, as revealed by abrogated morphology and defective acidification of the vacuole lumen. Together, we demonstrated that Mg deprivation affected immune evasion mechanisms by: reduced hyphal damage, enhanced β-1,3-glucan exposure and altered vacuole functioning. The study establishes that Mg availability is indispensable for successful C. albicans immune evasion and specific Mg dependent pathways could be targeted for therapy.
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Affiliation(s)
- Sandeep Hans
- Amity Institute of Biotechnology, Amity University Haryana, Manesar, Gurugram, India
| | - Zeeshan Fatima
- Amity Institute of Biotechnology, Amity University Haryana, Manesar, Gurugram, India
- * E-mail: (ZF); (SH)
| | - Aijaz Ahmad
- Clinical Microbiology and Infectious Diseases, Faculty of Health Sciences, School of Pathology, University of the Witwatersrand, Johannesburg, South Africa
- Infection Control, National Health Laboratory Service, Charlotte Maxeke Johannesburg Academic Hospital, Johannesburg, South Africa
| | - Saif Hameed
- Amity Institute of Biotechnology, Amity University Haryana, Manesar, Gurugram, India
- * E-mail: (ZF); (SH)
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13
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Yeon J, Park AR, Nguyen HTT, Gwak H, Kim J, Sang MK, Kim JC. Inhibition of Oomycetes by the Mixture of Maleic Acid and Copper Sulfate. PLANT DISEASE 2022; 106:960-965. [PMID: 34705489 DOI: 10.1094/pdis-07-21-1559-re] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Since the protective activity of the Bordeaux mixture against plant disease caused by oomycetes was discovered, copper compounds have been used for more than a century as an effective plant protection strategy. However, the application of excessive copper can cause adverse effects through long-term heavy metal accumulation in soils. Therefore, it is necessary to develop new strategies to reduce or replace copper in pesticides based on organic and low-input farming systems. Organic acids are eco-friendly. In this study, we tested the antifungal and anti-oomycete activity of maleic acid (MA) and copper sulfate (CS) against 13 plant pathogens. Treatment with a mixture of MA and CS showed strong anti-oomycetes activity against Phytophthora xcambivora, P. capsici, and P. cinnamomi. Moreover, the concentration of CS in the activated mixture of MA and CS was lower than that in the activated CS only, and the mixture showed synergy or partial synergy effects on the anti-oomycete activity. Application of a wettable powder formulation of MA and CS mixture (MCS 30WP; 26.67% MA and 3.33% CS) had excellent protective activity in pot experiments with control values of 73% Phytophthora blight on red pepper, 91% damping-off on cucumber, and 84% Pythium blight on creeping bentgrass, which are similar to those of the CS wettable powder formulation (6.67% CS) containing two times the CS content of MCS 30WP. These observations suggest that the synergistic effect of the MA and CS combination is a sustainable alternative for effective management of destructive oomycete diseases.
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Affiliation(s)
- Jehyeong Yeon
- Institute of Environmentally Friendly Agriculture, Department of Agricultural Chemistry, College of Agriculture and Life Science, Chonnam National University, Gwangju 61186, Republic of Korea
| | - Ae Ran Park
- Institute of Environmentally Friendly Agriculture, Department of Agricultural Chemistry, College of Agriculture and Life Science, Chonnam National University, Gwangju 61186, Republic of Korea
| | - Hang Thi Thu Nguyen
- Institute of Environmentally Friendly Agriculture, Department of Agricultural Chemistry, College of Agriculture and Life Science, Chonnam National University, Gwangju 61186, Republic of Korea
| | - Hanna Gwak
- Institute of Environmentally Friendly Agriculture, Department of Agricultural Chemistry, College of Agriculture and Life Science, Chonnam National University, Gwangju 61186, Republic of Korea
| | - Jiwon Kim
- Division of Agricultural Microbiology, National Institute of Agricultural Sciences, Rural Development Administration, Wanju 55365, Republic of Korea
- Department of Agricultural Biology, College of Agricultural & Life Sciences, Jeonbuk National University, Jeonju, 54896, Republic of Korea
| | - Mee Kyung Sang
- Division of Agricultural Microbiology, National Institute of Agricultural Sciences, Rural Development Administration, Wanju 55365, Republic of Korea
| | - Jin-Cheol Kim
- Institute of Environmentally Friendly Agriculture, Department of Agricultural Chemistry, College of Agriculture and Life Science, Chonnam National University, Gwangju 61186, Republic of Korea
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14
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15
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Lv Q, Yan L, Jiang Y. The Importance of Vacuolar Ion Homeostasis and Trafficking in Hyphal Development and Virulence in Candida albicans. Front Microbiol 2021; 12:779176. [PMID: 34956142 PMCID: PMC8696117 DOI: 10.3389/fmicb.2021.779176] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2021] [Accepted: 11/12/2021] [Indexed: 11/13/2022] Open
Abstract
The vacuole of Candida albicans plays a significant role in many processes including homeostasis control, cellular trafficking, dimorphic switching, and stress tolerance. Thus, understanding the factors affecting vacuole function is important for the identification of new drug targets needed in response to the world’s increasing levels of invasive infections and the growing issue of fungal drug resistance. Past studies have shown that vacuolar proton-translocating ATPases (V-ATPases) play a central role in pH homeostasis and filamentation. Vacuolar protein sorting components (VPS) regulate V-ATPases assembly and at the same time affect hyphal development. As well, vacuolar calcium exchange systems like Yvc1 and Pmc1 maintain cytosolic calcium levels while being affected by V-ATPases function. All these proteins play a role in the virulence and pathogenesis of C. albicans. This review highlights the relationships among V-ATPases, VPS, and vacuolar calcium exchange proteins while summarizing their importance in C. albicans infections.
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Affiliation(s)
- Quanzhen Lv
- School of Pharmacy, Naval Medical University, Shanghai, China
| | - Lan Yan
- School of Pharmacy, Naval Medical University, Shanghai, China
| | - Yuanying Jiang
- Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, China
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16
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Santra P, Amack JD. Loss of vacuolar-type H+-ATPase induces caspase-independent necrosis-like death of hair cells in zebrafish neuromasts. Dis Model Mech 2021; 14:dmm048997. [PMID: 34296747 PMCID: PMC8319552 DOI: 10.1242/dmm.048997] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Accepted: 06/15/2021] [Indexed: 01/24/2023] Open
Abstract
The vacuolar-type H+-ATPase (V-ATPase) is a multi-subunit proton pump that regulates cellular pH. V-ATPase activity modulates several cellular processes, but cell-type-specific functions remain poorly understood. Patients with mutations in specific V-ATPase subunits can develop sensorineural deafness, but the underlying mechanisms are unclear. Here, we show that V-ATPase mutations disrupt the formation of zebrafish neuromasts, which serve as a model to investigate hearing loss. V-ATPase mutant neuromasts are small and contain pyknotic nuclei that denote dying cells. Molecular markers and live imaging show that loss of V-ATPase induces mechanosensory hair cells in neuromasts, but not neighboring support cells, to undergo caspase-independent necrosis-like cell death. This is the first demonstration that loss of V-ATPase can lead to necrosis-like cell death in a specific cell type in vivo. Mechanistically, loss of V-ATPase reduces mitochondrial membrane potential in hair cells. Modulating the mitochondrial permeability transition pore, which regulates mitochondrial membrane potential, improves hair cell survival. These results have implications for understanding the causes of sensorineural deafness, and more broadly, reveal functions for V-ATPase in promoting survival of a specific cell type in vivo.
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Affiliation(s)
- Peu Santra
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, NY 13210, USA
| | - Jeffrey D. Amack
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, NY 13210, USA
- BioInspired Syracuse: Institute for Material and Living Systems, Syracuse, NY 13244, USA
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17
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Mao X, Yang L, Liu Y, Ma C, Ma T, Yu Q, Li M. Vacuole and Mitochondria Patch (vCLAMP) Protein Vam6 Is Involved in Maintenance of Mitochondrial and Vacuolar Functions under Oxidative Stress in Candida albicans. Antioxidants (Basel) 2021; 10:antiox10010136. [PMID: 33478009 PMCID: PMC7835768 DOI: 10.3390/antiox10010136] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 01/15/2021] [Accepted: 01/15/2021] [Indexed: 12/25/2022] Open
Abstract
Candida albicans is one of the most common opportunistic fungal pathogens in human beings. When infecting host cells, C. albicans is often exposed to oxidative stress from the host immune defense system. Maintenance of mitochondrial and vacuolar functions is crucial for its resistance to oxidative stress. However, the role of vacuole and mitochondria patchs (vCLAMPs) in cellular oxidative stress resistance and in the maintenance of organelle functions remains to be elucidated. Herein, the function of the vCLAMP protein Vam6 in response to oxidative stress was explored. The results showed that the vam6∆/∆ mutant exhibited obvious mitochondrial swelling, mtDNA damage, reduced activity of antioxidant enzymes, and abnormal vacuolar morphology under H2O2 treatment, indicating its important role in maintaining the structures and functions of both mitochondria and vacuoles under oxidative stress. Further studies showed that deletion of VAM6 attenuated hyphal development under oxidative stress. Moreover, loss of Vam6 obviously affected host tissue invasion and virulence of C. albicans. Taken together, this paper reveals the critical role of vCLAMPs in response to oxidative stress in C. albicans.
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18
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Kim JE, Vali SW, Nguyen TQ, Dancis A, Lindahl PA. Mössbauer and LC-ICP-MS investigation of iron trafficking between vacuoles and mitochondria in vma2ΔSaccharomyces cerevisiae. J Biol Chem 2020; 296:100141. [PMID: 33268384 PMCID: PMC7948489 DOI: 10.1074/jbc.ra120.015907] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 11/24/2020] [Accepted: 12/02/2020] [Indexed: 01/09/2023] Open
Abstract
Vacuoles are acidic organelles that store FeIII polyphosphate, participate in iron homeostasis, and have been proposed to deliver iron to mitochondria for iron–sulfur cluster (ISC) and heme biosynthesis. Vma2Δ cells have dysfunctional V-ATPases, rendering their vacuoles nonacidic. These cells have mitochondria that are iron-dysregulated, suggesting disruption of a putative vacuole-to-mitochondria iron trafficking pathway. To investigate this potential pathway, we examined the iron content of a vma2Δ mutant derived from W303 cells using Mössbauer and EPR spectroscopies and liquid chromatography interfaced with inductively-coupled-plasma mass spectrometry. Relative to WT cells, vma2Δ cells contained WT concentrations of iron but nonheme FeII dominated the iron content of fermenting and respiring vma2Δ cells, indicating that the vacuolar FeIII ions present in WT cells had been reduced. However, vma2Δ cells synthesized WT levels of ISCs/hemes and had normal aconitase activity. The iron content of vma2Δ mitochondria was similar to WT, all suggesting that iron delivery to mitochondria was not disrupted. Chromatograms of cytosolic flow–through solutions exhibited iron species with apparent masses of 600 and 800 Da for WT and vma2∆, respectively. Mutant cells contained high copper concentrations and high concentrations of a species assigned to metallothionein, indicating copper dysregulation. vma2Δ cells from previously studied strain BY4741 exhibited iron-associated properties more consistent with prior studies, suggesting subtle strain differences. Vacuoles with functional V-ATPases appear unnecessary in W303 cells for iron to enter mitochondria and be used in ISC/heme biosynthesis; thus, there appears to be no direct or dedicated vacuole-to-mitochondria iron trafficking pathway. The vma2Δ phenotype may arise from alterations in trafficking of iron directly from cytosol to mitochondria.
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Affiliation(s)
- Joshua E Kim
- Department of Chemistry, Texas A&M University, College Station, Texas, USA
| | - Shaik Waseem Vali
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas, USA
| | - Trang Q Nguyen
- Department of Chemistry, Texas A&M University, College Station, Texas, USA
| | - Andrew Dancis
- Department of Pharmacology, Physiology, and Neuroscience, New Jersey Medical School, Rutgers University, Newark, New Jersey, USA; Division of Hematology-Oncology, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Paul A Lindahl
- Department of Chemistry, Texas A&M University, College Station, Texas, USA; Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas, USA.
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19
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Fogarty S, Ouyang Y, Li L, Chen YC, Rane H, Manoni F, Parra KJ, Rutter J, Harran PG. Callyspongiolide Is a Potent Inhibitor of the Vacuolar ATPase. JOURNAL OF NATURAL PRODUCTS 2020; 83:3381-3386. [PMID: 33151675 DOI: 10.1021/acs.jnatprod.0c00813] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Callyspongiolide is a marine-derived macrolide that kills cells in a caspase-independent manner. NCI COMPARE analysis of human tumor cell line toxicity data for synthetic callyspongiolide indicated that its pattern of cytotoxicity correlated with that seen for concanamycin A, an inhibitor of the vacuolar-type H+-ATPase (V-ATPase). Using yeast as a model system, we report that treatment with synthetic callyspongiolide phenocopied a loss of V-ATPase activity including (1) inability to grow on a nonfermentable carbon source, (2) rescue of cell growth via supplementation with Fe2+, (3) pH-sensitive growth, and (4) a vacuolar acidification defect visualized using the fluorescent dye quinacrine. Crucially, in an in vitro assay, callyspongiolide was found to dose-dependently inhibit yeast V-ATPase (IC50 = 10 nM). Together, these data identify callyspongiolide as a new and highly potent V-ATPase inhibitor. Notably, callyspongiolide is the first V-ATPase inhibitor known to be expelled by Pdr5p.
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Affiliation(s)
- Sarah Fogarty
- Howard Hughes Medical Institute and Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, Utah 84132, United States
| | - Yeyun Ouyang
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, Utah 84132, United States
| | - Liubo Li
- Department of Chemistry and Biochemistry, University of California-Los Angeles, 607 Charles E. Young Drive East, Los Angeles, California 90095-1569, United States
| | - Yu-Chan Chen
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, Utah 84132, United States
| | - Hallie Rane
- Department of Biochemistry and Molecular Biology, School of Medicine, University of New Mexico Health Sciences Center, Albuquerque, New Mexico 87131, United States
| | - Francesco Manoni
- Department of Chemistry and Biochemistry, University of California-Los Angeles, 607 Charles E. Young Drive East, Los Angeles, California 90095-1569, United States
| | - Karlett J Parra
- Department of Biochemistry and Molecular Biology, School of Medicine, University of New Mexico Health Sciences Center, Albuquerque, New Mexico 87131, United States
| | - Jared Rutter
- Howard Hughes Medical Institute and Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, Utah 84132, United States
| | - Patrick G Harran
- Department of Chemistry and Biochemistry, University of California-Los Angeles, 607 Charles E. Young Drive East, Los Angeles, California 90095-1569, United States
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20
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Collins MP, Stransky LA, Forgac M. AKT Ser/Thr kinase increases V-ATPase-dependent lysosomal acidification in response to amino acid starvation in mammalian cells. J Biol Chem 2020; 295:9433-9444. [PMID: 32409581 PMCID: PMC7363138 DOI: 10.1074/jbc.ra120.013223] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 05/13/2020] [Indexed: 12/12/2022] Open
Abstract
The vacuolar H+-ATPase (V-ATPase) is an ATP-dependent proton pump that is essential for cellular homeostasis. V-ATPase activity is controlled by the regulated assembly of the enzyme from its component V1 and V0 domains. We previously reported that amino acid starvation rapidly increases V-ATPase assembly and activity in mammalian lysosomes, but the signaling pathways controlling this effect are unknown. In testing inhibitors of pathways important for controlling cellular metabolism, we found here that the cAMP-dependent protein kinase (PKA) inhibitor H89 increases lysosomal V-ATPase activity and blocks any further change upon starvation. The AMP-activated protein kinase (AMPK) inhibitor dorsomorphin decreased lysosomal V-ATPase activity and also blocked any increase upon starvation. However, CRISPR-mediated gene editing revealed that PKA and AMPK are not required for the starvation-dependent increase in lysosomal V-ATPase activity, indicating that H89 and dorsomorphin modify V-ATPase activity through other cellular targets. We next found that the AKT Ser/Thr kinase (AKT) inhibitor MK2206 blocks the starvation-dependent increase in lysosomal V-ATPase activity without altering basal activity. Expression of AKT1 or AKT3, but not AKT2, was required for increased lysosomal V-ATPase activity in response to amino acid starvation in mouse fibroblasts. Finally, HEK293T cells expressing only AKT1 responded normally to starvation, whereas cells expressing only AKT2 displayed a significantly reduced increase in V-ATPase activity and assembly upon starvation. These results show that AKT is required for controlling the rapid response of lysosomal V-ATPase activity to changes in amino acid availability and that this response depends on specific AKT isoforms.
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Affiliation(s)
- Michael P Collins
- Program in Cell, Molecular and Developmental Biology, Tufts University Graduate School of Biomedical Sciences, Boston, Massachusetts, USA
| | - Laura A Stransky
- Program in Cellular and Molecular Physiology, Tufts University Graduate School of Biomedical Sciences, Boston, Massachusetts, USA
| | - Michael Forgac
- Program in Cell, Molecular and Developmental Biology, Tufts University Graduate School of Biomedical Sciences, Boston, Massachusetts, USA
- Program in Cellular and Molecular Physiology, Tufts University Graduate School of Biomedical Sciences, Boston, Massachusetts, USA
- Department of Developmental, Molecular and Chemical Biology, Tufts University School of Medicine, Boston, Massachusetts, USA
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21
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Linder RA, Majumder A, Chakraborty M, Long A. Two Synthetic 18-Way Outcrossed Populations of Diploid Budding Yeast with Utility for Complex Trait Dissection. Genetics 2020; 215:323-342. [PMID: 32241804 PMCID: PMC7268983 DOI: 10.1534/genetics.120.303202] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Accepted: 03/31/2020] [Indexed: 02/07/2023] Open
Abstract
Advanced-generation multiparent populations (MPPs) are a valuable tool for dissecting complex traits, having more power than genome-wide association studies to detect rare variants and higher resolution than F2 linkage mapping. To extend the advantages of MPPs in budding yeast, we describe the creation and characterization of two outbred MPPs derived from 18 genetically diverse founding strains. We carried out de novo assemblies of the genomes of the 18 founder strains, such that virtually all variation segregating between these strains is known, and represented those assemblies as Santa Cruz Genome Browser tracks. We discovered complex patterns of structural variation segregating among the founders, including a large deletion within the vacuolar ATPase VMA1, several different deletions within the osmosensor MSB2, a series of deletions and insertions at PRM7 and the adjacent BSC1, as well as copy number variation at the dehydrogenase ALD2 Resequenced haploid recombinant clones from the two MPPs have a median unrecombined block size of 66 kb, demonstrating that the population is highly recombined. We pool-sequenced the two MPPs to 3270× and 2226× coverage and demonstrated that we can accurately estimate local haplotype frequencies using pooled data. We further downsampled the pool-sequenced data to ∼20-40× and showed that local haplotype frequency estimates remained accurate, with median error rates 0.8 and 0.6% at 20× and 40×, respectively. Haplotypes frequencies are estimated much more accurately than SNP frequencies obtained directly from the same data. Deep sequencing of the two populations revealed that 10 or more founders are present at a detectable frequency for > 98% of the genome, validating the utility of this resource for the exploration of the role of standing variation in the architecture of complex traits.
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Affiliation(s)
- Robert A Linder
- Department of Ecology and Evolutionary Biology, School of Biological Sciences, University of California, Irvine, California 92697-2525
| | - Arundhati Majumder
- Department of Ecology and Evolutionary Biology, School of Biological Sciences, University of California, Irvine, California 92697-2525
| | - Mahul Chakraborty
- Department of Ecology and Evolutionary Biology, School of Biological Sciences, University of California, Irvine, California 92697-2525
| | - Anthony Long
- Department of Ecology and Evolutionary Biology, School of Biological Sciences, University of California, Irvine, California 92697-2525
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22
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Collins MP, Forgac M. Regulation and function of V-ATPases in physiology and disease. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183341. [PMID: 32422136 DOI: 10.1016/j.bbamem.2020.183341] [Citation(s) in RCA: 106] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 04/30/2020] [Accepted: 05/03/2020] [Indexed: 02/07/2023]
Abstract
The vacuolar H+-ATPases (V-ATPases) are essential, ATP-dependent proton pumps present in a variety of eukaryotic cellular membranes. Intracellularly, V-ATPase-dependent acidification functions in such processes as membrane traffic, protein degradation, autophagy and the coupled transport of small molecules. V-ATPases at the plasma membrane of certain specialized cells function in such processes as bone resorption, sperm maturation and urinary acidification. V-ATPases also function in disease processes such as pathogen entry and cancer cell invasiveness, while defects in V-ATPase genes are associated with disorders such as osteopetrosis, renal tubular acidosis and neurodegenerative diseases. This review highlights recent advances in our understanding of V-ATPase structure, mechanism, function and regulation, with an emphasis on the signaling pathways controlling V-ATPase assembly in mammalian cells. The role of V-ATPases in cancer and other human pathologies, and the prospects for therapeutic intervention, are also discussed.
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Affiliation(s)
- Michael P Collins
- Cell, Molecular and Developmental Biology, Tufts University Graduate School of Biomedical Sciences, United States of America
| | - Michael Forgac
- Cell, Molecular and Developmental Biology, Tufts University Graduate School of Biomedical Sciences, United States of America; Dept. of Developmental, Molecular and Chemical Biology, Tufts University School of Medicine, Boston, MA 02111, United States of America.
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23
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Ndukwe JK, Aliyu GO, Onwosi CO, Chukwu KO, Ezugworie FN. Mechanisms of weak acid-induced stress tolerance in yeasts: Prospects for improved bioethanol production from lignocellulosic biomass. Process Biochem 2020. [DOI: 10.1016/j.procbio.2019.11.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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24
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Minematsu A, Miyazaki T, Shimamura S, Nishikawa H, Nakayama H, Takazono T, Saijo T, Yamamoto K, Imamura Y, Yanagihara K, Kohno S, Mukae H, Izumikawa K. Vacuolar proton-translocating ATPase is required for antifungal resistance and virulence of Candida glabrata. PLoS One 2019; 14:e0210883. [PMID: 30673768 PMCID: PMC6343876 DOI: 10.1371/journal.pone.0210883] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2018] [Accepted: 01/03/2019] [Indexed: 12/04/2022] Open
Abstract
Vacuolar proton-translocating ATPase (V-ATPase) is located in fungal vacuolar membranes. It is involved in multiple cellular processes, including the maintenance of intracellular ion homeostasis by maintaining acidic pH within the cell. The importance of V-ATPase in virulence has been demonstrated in several pathogenic fungi, including Candida albicans. However, it remains to be determined in the clinically important fungal pathogen Candida glabrata. Increasing multidrug resistance of C. glabrata is becoming a critical issue in the clinical setting. In the current study, we demonstrated that the plecomacrolide V-ATPase inhibitor bafilomycin B1 exerts a synergistic effect with azole antifungal agents, including fluconazole and voriconazole, against a C. glabrata wild-type strain. Furthermore, the deletion of the VPH2 gene encoding an assembly factor of V-ATPase was sufficient to interfere with V-ATPase function in C. glabrata, resulting in impaired pH homeostasis in the vacuole and increased sensitivity to a variety of environmental stresses, such as alkaline conditions (pH 7.4), ion stress (Na+, Ca2+, Mn2+, and Zn2+ stress), exposure to the calcineurin inhibitor FK506 and antifungal agents (azoles and amphotericin B), and iron limitation. In addition, virulence of C. glabrata Δvph2 mutant in a mouse model of disseminated candidiasis was reduced in comparison with that of the wild-type and VPH2-reconstituted strains. These findings support the notion that V-ATPase is a potential attractive target for the development of effective antifungal strategies.
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Affiliation(s)
- Asuka Minematsu
- Department of Infectious Diseases, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
- Department of Respiratory Medicine, Nagasaki University Hospital, Nagasaki, Japan
| | - Taiga Miyazaki
- Department of Infectious Diseases, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
- Department of Respiratory Medicine, Nagasaki University Hospital, Nagasaki, Japan
- * E-mail:
| | - Shintaro Shimamura
- Department of Respiratory Medicine, Nagasaki University Hospital, Nagasaki, Japan
| | - Hiroshi Nishikawa
- Department of Respiratory Medicine, Nagasaki University Hospital, Nagasaki, Japan
| | - Hironobu Nakayama
- Faculty of Pharmaceutical Sciences, Suzuka University of Medical Sciences, Mie, Japan
| | - Takahiro Takazono
- Department of Infectious Diseases, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
- Department of Respiratory Medicine, Nagasaki University Hospital, Nagasaki, Japan
| | - Tomomi Saijo
- Department of Respiratory Medicine, Nagasaki University Hospital, Nagasaki, Japan
| | - Kazuko Yamamoto
- Department of Respiratory Medicine, Nagasaki University Hospital, Nagasaki, Japan
| | - Yoshifumi Imamura
- Department of Respiratory Medicine, Nagasaki University Hospital, Nagasaki, Japan
| | - Katsunori Yanagihara
- Department of Laboratory Medicine, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
| | - Shigeru Kohno
- Department of Respiratory Medicine, Nagasaki University Hospital, Nagasaki, Japan
| | - Hiroshi Mukae
- Department of Respiratory Medicine, Nagasaki University Hospital, Nagasaki, Japan
| | - Koichi Izumikawa
- Department of Infectious Diseases, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
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25
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Houang J, Perrone GG, Pedrinazzi C, Longo L, Mawad D, Boughton PC, Ruys AJ, Lauto A. Genetic Tolerance to Rose Bengal Photodynamic Therapy and Antifungal Clinical Application for Onychomycosis. ADVANCED THERAPEUTICS 2018. [DOI: 10.1002/adtp.201800105] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Affiliation(s)
- Jessica Houang
- School of Aerospace; Mechanical and Mechatronic Engineering; University of Sydney; Sydney NSW 2006 Australia
| | - Gabriel G. Perrone
- School of Science and Health; Western Sydney University; Penrith NSW 2751 Australia
| | | | - Leonardo Longo
- School of Medicine; University of Siena; 53100 Siena Italy
| | - Damia Mawad
- School of Materials Science and Engineering; University of New South Wales; Sydney NSW 2052 Australia
- Australian Centre for NanoMedicine and ARC Centre of Excellence in Convergent BioNano Science and Technology; University of New South Wales; Sydney NSW 2052 Australia
- Centre for Advanced Macromolecular Design; University of New South Wales; Sydney NSW 2052 Australia
| | - Philip C. Boughton
- School of Aerospace; Mechanical and Mechatronic Engineering; University of Sydney; Sydney NSW 2006 Australia
| | - Andrew J. Ruys
- School of Aerospace; Mechanical and Mechatronic Engineering; University of Sydney; Sydney NSW 2006 Australia
| | - Antonio Lauto
- School of Science and Health; Western Sydney University; Penrith NSW 2751 Australia
- Biomedical Engineering and Neuroscience Research Group; The MARCS Institute; Western Sydney University; Penrith NSW 2751 Australia
- School of Medicine; Western Sydney University; Penrith NSW 2750 Australia
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26
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Accelerated invagination of vacuoles as a stress response in chronically heat-stressed yeasts. Sci Rep 2018; 8:2644. [PMID: 29422608 PMCID: PMC5805771 DOI: 10.1038/s41598-018-20781-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Accepted: 01/24/2018] [Indexed: 01/01/2023] Open
Abstract
When exposed to sublethal high temperatures, budding yeast cells can survive for a period of time; however, a sufficient amount of ubiquitin is necessary for this survival. To understand the nature of the stress, we examined the morphological changes in yeast cells, focusing on the vacuoles. Changes in vacuolar morphology were notable, and ruffled vacuolar membranes, accelerated invaginations of vacuolar membranes, and vesicle-like formations were observed. These changes occurred in the absence of Atg1, Atg9 or Ivy1 but appeared to require endosomal sorting proteins, such as Vps23, Vps24 or Pep12. Furthermore, the serial sections of the vacuoles analysed using an electron microscopic analysis revealed that spherical invaginated structures were linked together in a vacuole. Because degradation of cell surface proteins is induced from heat stress, fusion of endosomal and vacuolar membranes might occur frequently in heat-stressed cells, and yeast cells might be able to cope with a rapid increase in vacuolar surface area by such invaginations.
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Zhang K, Jia C, Yu Q, Xiao C, Dong Y, Zhang M, Zhang D, Zhao Q, Zhang B, Li M. Contribution of VMA5 to vacuolar function, stress response, ion homeostasis and autophagy in Candida albicans. Future Microbiol 2017; 12:1147-1166. [PMID: 28879785 DOI: 10.2217/fmb-2017-0029] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
AIM V-ATPase is a conservative multi-subunit enzyme in eukaryotes and modulates several cellular responses. This study aimed to illustrate the roles of Vma5 in vacuolar function, oxidative stress response, calcium homeostasis, autophagy and virulence. MATERIALS & METHODS The vma5Δ/Δ mutant was obtained using PCR-mediated homologous recombination. The functions of Vma5 were investigated by a series of biochemical and systemic infection methods. RESULTS Disruption of VMA5 led to growth inhibition, vacuolar dysfunction, disturbance of calcium homeostasis and inhibition of calcium-related oxidative stress response. Furthermore, its deletion caused defects in autophagy completion and hyphal development, and resulted in attenuated Candida albicans virulence. CONCLUSION Our findings provide new insights into V-ATPase functions in C. albicans, and reveal a potential candidate for development of antifungal drugs.
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Affiliation(s)
- Kai Zhang
- Department of Microbiology, Key Laboratory of Molecular Microbiology & Technology, College of Life Sciences, Nankai University, Ministry of Education, Tianjin 300071, China
| | - Chang Jia
- Department of Microbiology, Key Laboratory of Molecular Microbiology & Technology, College of Life Sciences, Nankai University, Ministry of Education, Tianjin 300071, China
| | - Qilin Yu
- Department of Microbiology, Key Laboratory of Molecular Microbiology & Technology, College of Life Sciences, Nankai University, Ministry of Education, Tianjin 300071, China
| | - Chenpeng Xiao
- Department of Microbiology, Key Laboratory of Molecular Microbiology & Technology, College of Life Sciences, Nankai University, Ministry of Education, Tianjin 300071, China
| | - Yijie Dong
- Department of Microbiology, Key Laboratory of Molecular Microbiology & Technology, College of Life Sciences, Nankai University, Ministry of Education, Tianjin 300071, China.,The State Key Laboratory for Biology of Plant Disease & Insect Pests, Institute of Plant protection, Chinese Academy of Agricultural Sciences, Beijing 100871, China
| | - Meng Zhang
- Department of Microbiology, Key Laboratory of Molecular Microbiology & Technology, College of Life Sciences, Nankai University, Ministry of Education, Tianjin 300071, China
| | - Dan Zhang
- Department of Microbiology, Key Laboratory of Molecular Microbiology & Technology, College of Life Sciences, Nankai University, Ministry of Education, Tianjin 300071, China
| | - Qiang Zhao
- Department of Zoology & Developmental Biology, College of Life Sciences, Nankai University, Tianjin, 300071, China
| | - Biao Zhang
- College of Language & Culture, Tianjin University of Traditional Chinese Medicine, Tianjin 300193, China
| | - Mingchun Li
- Department of Microbiology, Key Laboratory of Molecular Microbiology & Technology, College of Life Sciences, Nankai University, Ministry of Education, Tianjin 300071, China
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Oku M, Maeda Y, Kagohashi Y, Kondo T, Yamada M, Fujimoto T, Sakai Y. Evidence for ESCRT- and clathrin-dependent microautophagy. J Cell Biol 2017; 216:3263-3274. [PMID: 28838958 PMCID: PMC5626533 DOI: 10.1083/jcb.201611029] [Citation(s) in RCA: 133] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Revised: 04/27/2017] [Accepted: 07/24/2017] [Indexed: 12/20/2022] Open
Abstract
Microautophagy is a mode of autophagy in which the lysosomal or vacuolar membrane invaginates and engulfs target components. Oku et al. show that, upon a diauxic shift, yeast microautophagy involves recruitment of ESCRT proteins to the vacuolar membrane, including clathrin-interacting Vps27, and uptake of lipid droplets by the vacuole. Microautophagy refers to a mode of autophagy in which the lysosomal or vacuolar membrane invaginates and directly engulfs target components. The molecular machinery of membrane dynamics driving microautophagy is still elusive. Using immunochemical monitoring of yeast vacuolar transmembrane proteins, Vph1 and Pho8, fused to fluorescent proteins, we obtained evidence showing an induction of microautophagy after a diauxic shift in the yeast Saccharomyces cerevisiae. Components of the endosomal sorting complex required for transport machinery were found to be required for this process, and the gateway protein of the machinery, Vps27, was observed to change its localization onto the vacuolar membrane after a diauxic shift. We revealed the functional importance of Vps27’s interaction with clathrin in this microautophagy that also contributed to uptake of lipid droplets into the vacuole. This study sheds light on the molecular mechanism of microautophagy, which does not require the core Atg proteins.
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Affiliation(s)
- Masahide Oku
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Yuichiro Maeda
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Yoko Kagohashi
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Takeshi Kondo
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Mai Yamada
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Toyoshi Fujimoto
- Department of Anatomy and Molecular Cell Biology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Yasuyoshi Sakai
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto, Japan .,Research Unit for Physiological Chemistry, Center for the Promotion of Interdisciplinary Education and Research, Kyoto University, Kyoto, Japan
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Sharma V, Purushotham R, Kaur R. The Phosphoinositide 3-Kinase Regulates Retrograde Trafficking of the Iron Permease CgFtr1 and Iron Homeostasis in Candida glabrata. J Biol Chem 2016; 291:24715-24734. [PMID: 27729452 DOI: 10.1074/jbc.m116.751529] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Revised: 09/22/2016] [Indexed: 01/13/2023] Open
Abstract
The phosphoinositide 3-kinase (PI3K), which phosphorylates phosphatidylinositol and produces PI3P, has been implicated in protein trafficking, intracellular survival, and virulence in the pathogenic yeast Candida glabrata Here, we demonstrate PI3-kinase (CgVps34) to be essential for maintenance of cellular iron homeostasis. We examine how CgVps34 regulates the fundamental process of iron acquisition, and underscore its function in vesicular trafficking as a central determinant. RNA sequencing analysis revealed iron homeostasis genes to be differentially expressed upon CgVps34 disruption. Consistently, the Cgvps34Δ mutant displayed growth attenuation in low- and high-iron media, increased intracellular iron content, elevated mitochondrial aconitase activity, impaired biofilm formation, and extenuated mouse organ colonization potential. Furthermore, we demonstrate for the first time that C. glabrata cells respond to iron limitation by expressing the iron permease CgFtr1 primarily on the cell membrane, and to iron excess via internalization of the plasma membrane-localized CgFtr1 to the vacuole. Our data show that CgVps34 is essential for the latter process. We also report that macrophage-internalized C. glabrata cells express CgFtr1 on the cell membrane indicative of an iron-restricted macrophage internal milieu, and Cgvps34Δ cells display better survival in iron-enriched medium-cultured macrophages. Overall, our data reveal the centrality of PI3K signaling in iron metabolism and host colonization.
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Affiliation(s)
- Vandana Sharma
- From the Centre for DNA Fingerprinting and Diagnostics, Survey Nos. 728, 729, 730 and 734, Opposite Uppal Water Tank, Beside BSNL T E Building, Uppal, Hyderabad 500039, Ranga Reddy District, India and; the Graduate Studies, Manipal University, Manipal, India
| | - Rajaram Purushotham
- From the Centre for DNA Fingerprinting and Diagnostics, Survey Nos. 728, 729, 730 and 734, Opposite Uppal Water Tank, Beside BSNL T E Building, Uppal, Hyderabad 500039, Ranga Reddy District, India and
| | - Rupinder Kaur
- From the Centre for DNA Fingerprinting and Diagnostics, Survey Nos. 728, 729, 730 and 734, Opposite Uppal Water Tank, Beside BSNL T E Building, Uppal, Hyderabad 500039, Ranga Reddy District, India and.
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Mevers E, Saurí J, Liu Y, Moser A, Ramadhar TR, Varlan M, Williamson RT, Martin GE, Clardy J. Homodimericin A: A Complex Hexacyclic Fungal Metabolite. J Am Chem Soc 2016; 138:12324-7. [PMID: 27608853 PMCID: PMC5533454 DOI: 10.1021/jacs.6b07588] [Citation(s) in RCA: 85] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Microbes sense and respond to their environment with small molecules, and discovering these molecules and identifying their functions informs chemistry, biology, and medicine. As part of a study of molecular exchanges between termite-associated actinobacteria and pathogenic fungi, we uncovered a remarkable fungal metabolite, homodimericin A, which is strongly upregulated by the bacterial metabolite bafilomycin C1. Homodimericin A is a hexacyclic polyketide with a carbon backbone containing eight contiguous stereogenic carbons in a C20 hexacyclic core. Only half of its carbon atoms have an attached hydrogen, which presented a significant challenge for NMR-based structural analysis. In spite of its microbial production and rich stereochemistry, homodimericin A occurs naturally as a racemic mixture. A plausible nonenzymatic reaction cascade leading from two identical achiral monomers to homodimericin A is presented, and homodimericin A's formation by this path, a six-electron oxidation, could be a response to oxidative stress triggered by bafilomycin C1.
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Affiliation(s)
- Emily Mevers
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School , 240 Longwood Avenue, Boston, Massachusetts 02115, United States
| | - Josep Saurí
- Process Research and Development, NMR Structure Elucidation Group, Merck & Co., Inc. , Mail Stop RY800-C163, 126 East Lincoln Avenue, Rahway, New Jersey 07065 United States
| | - Yizhou Liu
- Process Research and Development, NMR Structure Elucidation Group, Merck & Co., Inc. , Mail Stop RY800-C163, 126 East Lincoln Avenue, Rahway, New Jersey 07065 United States
| | - Arvin Moser
- Advanced Chemistry Development, Inc. (ACD/Laboratories) Toronto Department, 8 King Street East, Suite 107, Toronto, ON M5C 1B5, Canada
| | - Timothy R Ramadhar
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School , 240 Longwood Avenue, Boston, Massachusetts 02115, United States
| | - Maria Varlan
- Advanced Chemistry Development, Inc. (ACD/Laboratories) Toronto Department, 8 King Street East, Suite 107, Toronto, ON M5C 1B5, Canada
| | - R Thomas Williamson
- Process Research and Development, NMR Structure Elucidation Group, Merck & Co., Inc. , Mail Stop RY800-C163, 126 East Lincoln Avenue, Rahway, New Jersey 07065 United States
| | - Gary E Martin
- Process Research and Development, NMR Structure Elucidation Group, Merck & Co., Inc. , Mail Stop RY800-C163, 126 East Lincoln Avenue, Rahway, New Jersey 07065 United States
| | - Jon Clardy
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School , 240 Longwood Avenue, Boston, Massachusetts 02115, United States
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Eloh K, Demurtas M, Mura MG, Deplano A, Onnis V, Sasanelli N, Maxia A, Caboni P. Potent Nematicidal Activity of Maleimide Derivatives on Meloidogyne incognita. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2016; 64:4876-4881. [PMID: 27249054 DOI: 10.1021/acs.jafc.6b02250] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Different maleimide derivatives were synthesized and assayed for their in vitro activity on the soil inhabiting, plant-parasitic nematode Meloidogyne incognita, also known as root-knot nematode. The compounds maleimide, N-ethylmaleimide, N-isopropylmaleimide, and N-isobutylmaleimide showed the strongest nematicidal activity on the second stage juveniles of the root-knot nematode with EC50/72h values of 2.6 ± 1.3, 5.1 ± 3.4, 16.2 ± 5.4, and 19.0 ± 9.0 mg/L, respectively. We also determined the nematicidal activity of copper sulfate, finding an EC50 value of 48.6 ± 29.8 mg/L. When maleimide at 1 mg/L was tested in combination with copper sulfate at 50 mg/L, we observed 100% mortality of the nematodes. We performed a GC-MS metabolomics analysis after treating nematodes with maleimide at 8 mg/L for 24 h. This analysis revealed altered fatty acids and diglyceride metabolites such as oleic acid, palmitic acid, and 1-monopalmitin. Our results suggest that maleimide may be used as a new interesting building block for developing new nematicides in combination with copper salts.
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Affiliation(s)
- Kodjo Eloh
- Department of Life and Environmental Sciences, University of Cagliari , via Ospedale 72, 09124 Cagliari, Italy
| | - Monica Demurtas
- Department of Life and Environmental Sciences, University of Cagliari , via Ospedale 72, 09124 Cagliari, Italy
| | - Manuel Giacomo Mura
- Department of Life and Environmental Sciences, University of Cagliari , via Ospedale 72, 09124 Cagliari, Italy
| | - Alessandro Deplano
- Department of Life and Environmental Sciences, University of Cagliari , via Ospedale 72, 09124 Cagliari, Italy
| | - Valentina Onnis
- Department of Life and Environmental Sciences, University of Cagliari , via Ospedale 72, 09124 Cagliari, Italy
| | - Nicola Sasanelli
- Institute for Sustainable Plant Protection, CNR , via G. Amendola 122/D, 70126 Bari, Italy
| | - Andrea Maxia
- Department of Life and Environmental Sciences, University of Cagliari , via Ospedale 72, 09124 Cagliari, Italy
| | - Pierluigi Caboni
- Department of Life and Environmental Sciences, University of Cagliari , via Ospedale 72, 09124 Cagliari, Italy
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32
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Chan CY, Dominguez D, Parra KJ. Regulation of Vacuolar H+-ATPase (V-ATPase) Reassembly by Glycolysis Flow in 6-Phosphofructo-1-kinase (PFK-1)-deficient Yeast Cells. J Biol Chem 2016; 291:15820-9. [PMID: 27226568 DOI: 10.1074/jbc.m116.717488] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Indexed: 01/21/2023] Open
Abstract
Yeast 6-phosphofructo-1-kinase (PFK-1) has two subunits, Pfk1p and Pfk2p. Deletion of Pfk2p alters glucose-dependent V-ATPase reassembly and vacuolar acidification (Chan, C. Y., and Parra, K. J. (2014) Yeast phosphofructokinase-1 subunit Pfk2p is necessary for pH homeostasis and glucose-dependent vacuolar ATPase reassembly. J. Biol. Chem. 289, 19448-19457). This study capitalized on the mechanisms suppressing vacuolar H(+)-ATPase (V-ATPase) in pfk2Δ to gain new knowledge of the mechanisms underlying glucose-dependent V-ATPase regulation. Because V-ATPase is fully assembled in pfk2Δ, and glycolysis partially suppressed at steady state, we manipulated glycolysis and assessed its direct involvement on V-ATPase function. At steady state, the ratio of proton transport to ATP hydrolysis increased 24% after increasing the glucose concentration from 2% to 4% to enhance the glycolysis flow in pfk2Δ. Tighter coupling restored vacuolar pH when glucose was abundant and glycolysis operated below capacity. After readdition of glucose to glucose-deprived cells, glucose-dependent V1Vo reassembly was proportional to the glycolysis flow. Readdition of 2% glucose to pfk2Δ cells, which restored 62% of ethanol concentration, led to equivalent 60% V1Vo reassembly levels. Steady-state level of assembly (100% reassembly) was reached at 4% glucose when glycolysis reached a threshold in pfk2Δ (≥40% the wild-type flow). At 4% glucose, the level of Pfk1p co-immunoprecipitated with V-ATPase decreased 58% in pfk2Δ, suggesting that Pfk1p binding to V-ATPase may be inhibitory in the mutant. We concluded that V-ATPase activity at steady state and V-ATPase reassembly after readdition of glucose to glucose-deprived cells are controlled by the glycolysis flow. We propose a new mechanism by which glucose regulates V-ATPase catalytic activity that occurs at steady state without changing V1Vo assembly.
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Affiliation(s)
- Chun-Yuan Chan
- From the Department of Biochemistry and Molecular Biology, School of Medicine, University of New Mexico Health Sciences Center, Albuquerque, New Mexico 87131
| | - Dennis Dominguez
- From the Department of Biochemistry and Molecular Biology, School of Medicine, University of New Mexico Health Sciences Center, Albuquerque, New Mexico 87131
| | - Karlett J Parra
- From the Department of Biochemistry and Molecular Biology, School of Medicine, University of New Mexico Health Sciences Center, Albuquerque, New Mexico 87131
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Croft CA, Culibrk L, Moore MM, Tebbutt SJ. Interactions of Aspergillus fumigatus Conidia with Airway Epithelial Cells: A Critical Review. Front Microbiol 2016; 7:472. [PMID: 27092126 PMCID: PMC4823921 DOI: 10.3389/fmicb.2016.00472] [Citation(s) in RCA: 102] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 03/21/2016] [Indexed: 02/05/2023] Open
Abstract
Aspergillus fumigatus is an environmental filamentous fungus that also acts as an opportunistic pathogen able to cause a variety of symptoms, from an allergic response to a life-threatening disseminated fungal infection. The infectious agents are inhaled conidia whose first point of contact is most likely to be an airway epithelial cell (AEC). The interaction between epithelial cells and conidia is multifaceted and complex, and has implications for later steps in pathogenesis. Increasing evidence has demonstrated a key role for the airway epithelium in the response to respiratory pathogens, particularly at early stages of infection; therefore, elucidating the early stages of interaction of conidia with AECs is essential to understand the establishment of infection in cohorts of at-risk patients. Here, we present a comprehensive review of the early interactions between A. fumigatus and AECs, including bronchial and alveolar epithelial cells. We describe mechanisms of adhesion, internalization of conidia by AECs, the immune response of AECs, as well as the role of fungal virulence factors, and patterns of fungal gene expression characteristic of early infection. A clear understanding of the mechanisms involved in the early establishment of infection by A. fumigatus could point to novel targets for therapy and prophylaxis.
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Affiliation(s)
- Carys A Croft
- Centre for Heart Lung Innovation, St. Paul's Hospital, University of British Columbia, Vancouver BC, Canada
| | - Luka Culibrk
- Centre for Heart Lung Innovation, St. Paul's Hospital, University of British Columbia, Vancouver BC, Canada
| | - Margo M Moore
- Department of Biological Sciences, Simon Fraser University, Burnaby BC, Canada
| | - Scott J Tebbutt
- Centre for Heart Lung Innovation, St. Paul's Hospital, University of British Columbia, VancouverBC, Canada; Prevention of Organ Failure Centre of Excellence, VancouverBC, Canada; Department of Medicine, Division of Respiratory Medicine, University of British Columbia, VancouverBC, Canada
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Callaghan PS, Siriwardana A, Hassett MR, Roepe PD. Plasmodium falciparum chloroquine resistance transporter (PfCRT) isoforms PH1 and PH2 perturb vacuolar physiology. Malar J 2016; 15:186. [PMID: 27036417 PMCID: PMC4815217 DOI: 10.1186/s12936-016-1238-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2015] [Accepted: 03/16/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Recent work has perfected yeast-based methods for measuring drug transport by the Plasmodium falciparum chloroquine (CQ) resistance transporter (PfCRT). METHODS The approach relies on inducible heterologous expression of PfCRT in Saccharomyces cerevisiae yeast. In these experiments selecting drug concentrations are not toxic to the yeast, nor is expression of PfCRT alone toxic. Only when PfCRT is expressed in the presence of CQ is the growth of yeast impaired, due to inward transport of chloroquine (CQ) via the transporter. RESULTS During analysis of all 53 known naturally occurring PfCRT isoforms, two isoforms (PH1 and PH2 PfCRT) were found to be intrinsically toxic to yeast, even in the absence of CQ. Additional analysis of six very recently identified PfCRT isoforms from Malaysia also showed some toxicity. In this paper the nature of this yeast toxicity is examined. Data also show that PH1 and PH2 isoforms of PfCRT transport CQ with an efficiency intermediate to that catalyzed by previously studied CQR conferring isoforms. Mutation of PfCRT at position 160 is found to perturb vacuolar physiology, suggesting a fitness cost to position 160 amino acid substitutions. CONCLUSION These data further define the wide range of activities that exist for PfCRT isoforms found in P. falciparum isolates from around the globe.
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Affiliation(s)
- Paul S Callaghan
- Department of Chemistry, Georgetown University, 37th and O Streets, NW, Washington, DC, 20057, USA.,Department of Biochemistry, Cellular and Molecular Biology, Georgetown University, 37th and O Streets, NW, Washington, DC, 20057, USA
| | - Amila Siriwardana
- Department of Chemistry, Georgetown University, 37th and O Streets, NW, Washington, DC, 20057, USA.,Department of Biochemistry, Cellular and Molecular Biology, Georgetown University, 37th and O Streets, NW, Washington, DC, 20057, USA
| | - Matthew R Hassett
- Department of Chemistry, Georgetown University, 37th and O Streets, NW, Washington, DC, 20057, USA.,Department of Biochemistry, Cellular and Molecular Biology, Georgetown University, 37th and O Streets, NW, Washington, DC, 20057, USA
| | - Paul D Roepe
- Department of Chemistry, Georgetown University, 37th and O Streets, NW, Washington, DC, 20057, USA. .,Department of Biochemistry, Cellular and Molecular Biology, Georgetown University, 37th and O Streets, NW, Washington, DC, 20057, USA.
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McGuire C, Cotter K, Stransky L, Forgac M. Regulation of V-ATPase assembly and function of V-ATPases in tumor cell invasiveness. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2016; 1857:1213-1218. [PMID: 26906430 DOI: 10.1016/j.bbabio.2016.02.010] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Revised: 02/16/2016] [Accepted: 02/17/2016] [Indexed: 02/04/2023]
Abstract
V-ATPases are ATP-driven proton pumps that function within both intracellular compartments and the plasma membrane in a wide array of normal physiological and pathophysiological processes. V-ATPases are composed of a peripheral V(1) domain that hydrolyzes ATP and an integral V(0) domain that transports protons. Regulated assembly of the V-ATPase represents an important mechanism of regulating V-ATPase activity in response to a number of environmental cues. Our laboratory has demonstrated that glucose-dependent assembly of the V-ATPase complex in yeast is controlled by the Ras/cAMP/PKA pathway. By contrast, increased assembly of the V-ATPase during dendritic cell maturation involves the PI-3 kinase and mTORC1 pathways. Recently, we have shown that amino acids regulate V-ATPase assembly in mammalian cells, possibly as a means to maintain adequate levels of amino acids upon nutrient starvation. V-ATPases have also been implicated in cancer cell survival and invasion. V-ATPases are targeted to different cellular membranes by isoforms of subunit a, with a3 targeting V-ATPases to the plasma membrane of osteoclasts. We have shown that highly invasive human breast cancer cell lines express higher levels of the a3 isoform than poorly invasive lines and that knockdown of a3 reduces both expression of V-ATPases at the plasma membrane and in vitro invasion of breast tumor cells. Moreover, overexpression of a3 in a non-invasive breast epithelial line increases both plasma membrane V-ATPases and in vitro invasion. Finally, specific ablation of plasma membrane V-ATPases in highly invasive human breast cancer cells using either an antibody or small molecule approach inhibits both in vitro invasion and migration. These results suggest that plasma membrane and a3-containing V-ATPases represent a novel and important target in the development of therapeutics to limit breast cancer metastasis. This article is part of a Special Issue entitled 'EBEC 2016: 19th European Bioenergetics Conference, Riva del Garda, Italy, July 2-6, 2016', edited by Prof. Paolo Bernardi.
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Affiliation(s)
- Christina McGuire
- Department of Developmental, Molecular and Chemical Biology, Tufts University School of Medicine, 136 Harrison Ave., Boston, MA 02111, United States
| | - Kristina Cotter
- Department of Developmental, Molecular and Chemical Biology, Tufts University School of Medicine, 136 Harrison Ave., Boston, MA 02111, United States
| | - Laura Stransky
- Department of Developmental, Molecular and Chemical Biology, Tufts University School of Medicine, 136 Harrison Ave., Boston, MA 02111, United States
| | - Michael Forgac
- Department of Developmental, Molecular and Chemical Biology, Tufts University School of Medicine, 136 Harrison Ave., Boston, MA 02111, United States
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Yenush L. Potassium and Sodium Transport in Yeast. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 892:187-228. [DOI: 10.1007/978-3-319-25304-6_8] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Abstract
Despite diverse and changing extracellular environments, fungi maintain a relatively constant cytosolic pH and numerous organelles of distinct lumenal pH. Key players in fungal pH control are V-ATPases and the P-type proton pump Pma1. These two proton pumps act in concert with a large array of other transporters and are highly regulated. The activities of Pma1 and the V-ATPase are coordinated under some conditions, suggesting that pH in the cytosol and organelles is not controlled independently. Genomic studies, particularly in the highly tractable S. cerevisiae, are beginning to provide a systems-level view of pH control, including transcriptional responses to acid or alkaline ambient pH and definition of the full set of regulators required to maintain pH homeostasis. Genetically encoded pH sensors have provided new insights into localized mechanisms of pH control, as well as highlighting the dynamic nature of pH responses to the extracellular environment. Recent studies indicate that cellular pH plays a genuine signaling role that connects nutrient availability and growth rate through a number of mechanisms. Many of the pH control mechanisms found in S. cerevisiae are shared with other fungi, with adaptations for their individual physiological contexts. Fungi deploy certain proton transport and pH control mechanisms not shared with other eukaryotes; these regulators of cellular pH are potential antifungal targets. This review describes current and emerging knowledge proton transport and pH control mechanisms in S. cerevisiae and briefly discusses how these mechanisms vary among fungi.
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Teixeira V, Medeiros TC, Vilaça R, Ferreira J, Moradas-Ferreira P, Costa V. Ceramide signaling targets the PP2A-like protein phosphatase Sit4p to impair vacuolar function, vesicular trafficking and autophagy in Isc1p deficient cells. Biochim Biophys Acta Mol Cell Biol Lipids 2015; 1861:21-33. [PMID: 26477382 DOI: 10.1016/j.bbalip.2015.10.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Revised: 09/09/2015] [Accepted: 10/14/2015] [Indexed: 02/02/2023]
Abstract
The vacuoles play important roles in cellular homeostasis and their functions include the digestion of cytoplasmic material and organelles derived from autophagy. Conserved nutrient signaling pathways regulate vacuolar function and autophagy, ensuring normal cell and organismal development and aging. Recent evidence implicates sphingolipids in the modulation of these processes, but the impact of ceramide signaling on vacuolar dynamics and autophagy remains largely unknown. Here, we show that yeast cells lacking Isc1p, an orthologue of mammalian neutral sphingomyelinase type 2, exhibit vacuolar fragmentation and dysfunctions, namely decreased Pep4p-mediated proteolysis and V-ATPase activity, which impairs vacuolar acidification. Moreover, these phenotypes are suppressed by downregulation of the ceramide-activated protein phosphatase Sit4p. The isc1Δ cells also exhibit defective Cvt and vesicular trafficking in a Sit4p-dependent manner, ultimately contributing to a reduced autophagic flux. Importantly, these phenotypes are also suppressed by downregulation of the nutrient signaling kinase TORC1, which is known to inhibit Sit4p and autophagy, or Sch9p. These results support a model in which Sit4p functions downstream of Isc1p in a TORC1-independent, ceramide-dependent signaling branch that impairs vacuolar function and vesicular trafficking, leading to autophagic defects in yeast.
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Affiliation(s)
- Vitor Teixeira
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Rua Alfredo Allen s/n, 4200-135 Porto, Portugal; IBMC, Instituto de Biologia Molecular e Celular, Rua do Campo Alegre, 823, 4150-180 Porto, Portugal; ICBAS, Instituto de Ciências Biomédicas Abel Salazar, Departamento de Biologia Molecular, Universidade do Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal
| | - Tânia C Medeiros
- IBMC, Instituto de Biologia Molecular e Celular, Rua do Campo Alegre, 823, 4150-180 Porto, Portugal
| | - Rita Vilaça
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Rua Alfredo Allen s/n, 4200-135 Porto, Portugal; IBMC, Instituto de Biologia Molecular e Celular, Rua do Campo Alegre, 823, 4150-180 Porto, Portugal
| | - João Ferreira
- IBMC, Instituto de Biologia Molecular e Celular, Rua do Campo Alegre, 823, 4150-180 Porto, Portugal
| | - Pedro Moradas-Ferreira
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Rua Alfredo Allen s/n, 4200-135 Porto, Portugal; IBMC, Instituto de Biologia Molecular e Celular, Rua do Campo Alegre, 823, 4150-180 Porto, Portugal; ICBAS, Instituto de Ciências Biomédicas Abel Salazar, Departamento de Biologia Molecular, Universidade do Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal
| | - Vítor Costa
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Rua Alfredo Allen s/n, 4200-135 Porto, Portugal; IBMC, Instituto de Biologia Molecular e Celular, Rua do Campo Alegre, 823, 4150-180 Porto, Portugal; ICBAS, Instituto de Ciências Biomédicas Abel Salazar, Departamento de Biologia Molecular, Universidade do Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal.
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Couoh-Cardel S, Milgrom E, Wilkens S. Affinity Purification and Structural Features of the Yeast Vacuolar ATPase Vo Membrane Sector. J Biol Chem 2015; 290:27959-71. [PMID: 26416888 DOI: 10.1074/jbc.m115.662494] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Indexed: 12/27/2022] Open
Abstract
The membrane sector (Vo) of the proton pumping vacuolar ATPase (V-ATPase, V1Vo-ATPase) from Saccharomyces cerevisiae was purified to homogeneity, and its structure was characterized by EM of single molecules and two-dimensional crystals. Projection images of negatively stained Vo two-dimensional crystals showed a ring-like structure with a large asymmetric mass at the periphery of the ring. A cryo-EM reconstruction of Vo from single-particle images showed subunits a and d in close contact on the cytoplasmic side of the proton channel. A comparison of three-dimensional reconstructions of free Vo and Vo as part of holo V1Vo revealed that the cytoplasmic N-terminal domain of subunit a (aNT) must undergo a large conformational change upon enzyme disassembly or (re)assembly from Vo, V1, and subunit C. Isothermal titration calorimetry using recombinant subunit d and aNT revealed that the two proteins bind each other with a Kd of ~5 μm. Treatment of the purified Vo sector with 1-palmitoyl-2-hydroxy-sn-glycero-3-[phospho-rac-(1-glycerol)] resulted in selective release of subunit d, allowing purification of a VoΔd complex. Passive proton translocation assays revealed that both Vo and VoΔd are impermeable to protons. We speculate that the structural change in subunit a upon release of V1 from Vo during reversible enzyme dissociation plays a role in blocking passive proton translocation across free Vo and that the interaction between aNT and d seen in free Vo functions to stabilize the Vo sector for efficient reassembly of V1Vo.
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Affiliation(s)
- Sergio Couoh-Cardel
- From the Department of Biochemistry and Molecular Biology, State University of New York Upstate Medical University, Syracuse, New York 13210
| | - Elena Milgrom
- From the Department of Biochemistry and Molecular Biology, State University of New York Upstate Medical University, Syracuse, New York 13210
| | - Stephan Wilkens
- From the Department of Biochemistry and Molecular Biology, State University of New York Upstate Medical University, Syracuse, New York 13210
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Deranieh RM, Shi Y, Tarsio M, Chen Y, McCaffery JM, Kane PM, Greenberg ML. Perturbation of the Vacuolar ATPase: A NOVEL CONSEQUENCE OF INOSITOL DEPLETION. J Biol Chem 2015; 290:27460-72. [PMID: 26324718 DOI: 10.1074/jbc.m115.683706] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Indexed: 11/06/2022] Open
Abstract
Depletion of inositol has profound effects on cell function and has been implicated in the therapeutic effects of drugs used to treat epilepsy and bipolar disorder. We have previously shown that the anticonvulsant drug valproate (VPA) depletes inositol by inhibiting myo-inositol-3-phosphate synthase, the enzyme that catalyzes the first and rate-limiting step of inositol biosynthesis. To elucidate the cellular consequences of inositol depletion, we screened the yeast deletion collection for VPA-sensitive mutants and identified mutants in vacuolar sorting and the vacuolar ATPase (V-ATPase). Inositol depletion caused by starvation of ino1Δ cells perturbed the vacuolar structure and decreased V-ATPase activity and proton pumping in isolated vacuolar vesicles. VPA compromised the dynamics of phosphatidylinositol 3,5-bisphosphate (PI3,5P2) and greatly reduced V-ATPase proton transport in inositol-deprived wild-type cells. Osmotic stress, known to increase PI3,5P2 levels, did not restore PI3,5P2 homeostasis nor did it induce vacuolar fragmentation in VPA-treated cells, suggesting that perturbation of the V-ATPase is a consequence of altered PI3,5P2 homeostasis under inositol-limiting conditions. This study is the first to demonstrate that inositol depletion caused by starvation of an inositol synthesis mutant or by the inositol-depleting drug VPA leads to perturbation of the V-ATPase.
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Affiliation(s)
- Rania M Deranieh
- From the Department of Biological Sciences, Wayne State University, Detroit, Michigan 48202
| | - Yihui Shi
- From the Department of Biological Sciences, Wayne State University, Detroit, Michigan 48202
| | - Maureen Tarsio
- the Department of Biochemistry and Molecular Biology, State University of New York Upstate Medical University, Syracuse, New York 13210, and
| | - Yan Chen
- From the Department of Biological Sciences, Wayne State University, Detroit, Michigan 48202
| | - J Michael McCaffery
- the Integrated Imaging Center, Department of Biology, Johns Hopkins University, Baltimore, Maryland 21218
| | - Patricia M Kane
- the Department of Biochemistry and Molecular Biology, State University of New York Upstate Medical University, Syracuse, New York 13210, and
| | - Miriam L Greenberg
- From the Department of Biological Sciences, Wayne State University, Detroit, Michigan 48202,
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ERG2 and ERG24 Are Required for Normal Vacuolar Physiology as Well as Candida albicans Pathogenicity in a Murine Model of Disseminated but Not Vaginal Candidiasis. EUKARYOTIC CELL 2015; 14:1006-16. [PMID: 26231054 DOI: 10.1128/ec.00116-15] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Accepted: 07/29/2015] [Indexed: 01/21/2023]
Abstract
Several important classes of antifungal agents, including the azoles, act by blocking ergosterol biosynthesis. It was recently reported that the azoles cause massive disruption of the fungal vacuole in the prevalent human pathogen Candida albicans. This is significant because normal vacuolar function is required to support C. albicans pathogenicity. This study examined the impact of the morpholine antifungals, which inhibit later steps of ergosterol biosynthesis, on C. albicans vacuolar integrity. It was found that overexpression of either the ERG2 or ERG24 gene, encoding C-8 sterol isomerase or C-14 sterol reductase, respectively, suppressed C. albicans sensitivity to the morpholines. In addition, both erg2Δ/Δ and erg24Δ/Δ mutants were hypersensitive to the morpholines. These data are consistent with the antifungal activity of the morpholines depending upon the simultaneous inhibition of both Erg2p and Erg24p. The vacuoles within both erg2Δ/Δ and erg24Δ/Δ C. albicans strains exhibited an aberrant morphology and accumulated large quantities of the weak base quinacrine, indicating enhanced vacuolar acidification compared with that of control strains. Both erg mutants exhibited significant defects in polarized hyphal growth and were avirulent in a mouse model of disseminated candidiasis. Surprisingly, in a mouse model of vaginal candidiasis, both mutants colonized mice at high levels and induced a pathogenic response similar to that with the controls. Thus, while targeting Erg2p or Erg24p alone could provide a potentially efficacious therapy for disseminated candidiasis, it may not be an effective strategy to treat vaginal infections. The potential value of drugs targeting these enzymes as adjunctive therapies is discussed.
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42
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Smardon AM, Kane PM. Loss of vacuolar H+-ATPase activity in organelles signals ubiquitination and endocytosis of the yeast plasma membrane proton pump Pma1p. J Biol Chem 2014; 289:32316-32326. [PMID: 25271159 DOI: 10.1074/jbc.m114.574442] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Yeast mutants lacking the intracellular V-ATPase proton pump (vma mutants) have reduced levels of the Pma1p proton pump at the plasma membrane and increased levels in organelles including the vacuolar lumen. We examined the mechanism and physiological consequences of Pma1p mislocalization. Pma1p is ubiquitinated in vma mutants, and ubiquitination depends on the ubiquitin ligase Rsp5p and the arrestin-related adaptor protein Rim8p. vma mutant strains containing rsp5 or rim8 mutations maintain Pma1p at the plasma membrane, suggesting that ubiquitination is required for Pma1p internalization. Acute inhibition of V-ATPase activity with concanamycin A triggers Pma1p ubiquitination and internalization. In an endocytosis-deficient mutant (end4Δ) Pma1p is ubiquitinated but retained at the plasma membrane during concanamycin A treatment. Consistent with specificity in signaling loss of V-ATPase activity to Pma1p, another plasma membrane transporter, Mup1p, is not internalized in a vma mutant, and loss of the Mup1p adaptor Art1p does not prevent Pma1p internalization in a vma mutant. Very poor growth of vma2 rsp5-1 and vma2 rim8Δ double mutants suggests that Pma1p internalization benefits the vma mutants. We hypothesize that loss of V-ATPase-mediated organelle acidification signals ubiquitination, internalization, and degradation of a portion of Pma1p as a means of balancing overall pH homeostasis.
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Affiliation(s)
- Anne M Smardon
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, New York 13210
| | - Patricia M Kane
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, New York 13210.
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43
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Jia C, Yu Q, Xu N, Zhang B, Dong Y, Ding X, Chen Y, Zhang B, Xing L, Li M. Role of TFP1 in vacuolar acidification, oxidative stress and filamentous development in Candida albicans. Fungal Genet Biol 2014; 71:58-67. [PMID: 25220074 DOI: 10.1016/j.fgb.2014.08.012] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Revised: 08/21/2014] [Accepted: 08/25/2014] [Indexed: 10/24/2022]
Abstract
The vacuolar-type H(+)-ATPase (V-ATPase) is a multiprotein complex consisting of the V0 and V1 sectors, and is required for vacuolar acidification and virulence in the opportunistic fungal pathogen Candida albicans. In this study, we identified C. albicans Tfp1 as a putative subunit of V-ATPase, and explored its importance in multiple cellular processes. Our results revealed that Tfp1 played an essential role in vacuolar acidification and endocytic trafficking. In addition, the tfp1Δ/Δ mutant was sensitive to alkaline pH and elevated calcium concentrations, which is characteristic of loss of V-ATPase activity. The mutant also showed hypersensitivity to metal ions which might be attributed to a defect in sequestration of toxic ions to the vacuole through proton gradient produced by V-ATPase. Interestingly, deletion of TFP1 triggered endogenous oxidative stress even without exogenous oxidants. Compared with the wild-type strain, the tfp1Δ/Δ mutant showed significantly higher ROS levels and lower expression levels of redox-related genes with the addition of hydrogen peroxide (H2O2). Western blotting analysis showed that deletion of TFP1 significantly reduced the expression of Cap1 under H2O2 treatment, which contributes to the regulation of genes involved in the oxidative stress response. Furthermore, the tfp1Δ/Δ mutant showed significantly impaired filamentous development in hyphal induction media, and was avirulent in a mouse model of systemic candidiasis. Taken together, our results suggested that the putative V1 subunit Tfp1 is essential for vacuolar function and C. albicans pathogenesis, and provided a promising candidate for antifungal drugs.
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Affiliation(s)
- Chang Jia
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, PR China
| | - Qilin Yu
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, PR China
| | - Ning Xu
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, PR China
| | - Bing Zhang
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, PR China
| | - Yijie Dong
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, PR China
| | - Xiaohui Ding
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, PR China
| | - Yulu Chen
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, PR China
| | - Biao Zhang
- Tianjin University of Traditional Chinese Medicine, Tianjin, PR China
| | - Laijun Xing
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, PR China
| | - Mingchun Li
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, PR China.
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44
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Ruckenstuhl C, Netzberger C, Entfellner I, Carmona-Gutierrez D, Kickenweiz T, Stekovic S, Gleixner C, Schmid C, Klug L, Sorgo AG, Eisenberg T, Büttner S, Mariño G, Koziel R, Jansen-Dürr P, Fröhlich KU, Kroemer G, Madeo F. Lifespan extension by methionine restriction requires autophagy-dependent vacuolar acidification. PLoS Genet 2014; 10:e1004347. [PMID: 24785424 PMCID: PMC4006742 DOI: 10.1371/journal.pgen.1004347] [Citation(s) in RCA: 173] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2013] [Accepted: 03/19/2014] [Indexed: 11/19/2022] Open
Abstract
Reduced supply of the amino acid methionine increases longevity across species through an as yet elusive mechanism. Here, we report that methionine restriction (MetR) extends yeast chronological lifespan in an autophagy-dependent manner. Single deletion of several genes essential for autophagy (ATG5, ATG7 or ATG8) fully abolished the longevity-enhancing capacity of MetR. While pharmacological or genetic inhibition of TOR1 increased lifespan in methionine-prototroph yeast, TOR1 suppression failed to extend the longevity of methionine-restricted yeast cells. Notably, vacuole-acidity was specifically enhanced by MetR, a phenotype that essentially required autophagy. Overexpression of vacuolar ATPase components (Vma1p or Vph2p) suffices to increase chronological lifespan of methionine-prototrophic yeast. In contrast, lifespan extension upon MetR was prevented by inhibition of vacuolar acidity upon disruption of the vacuolar ATPase. In conclusion, autophagy promotes lifespan extension upon MetR and requires the subsequent stimulation of vacuolar acidification, while it is epistatic to the equally autophagy-dependent anti-aging pathway triggered by TOR1 inhibition or deletion.
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Affiliation(s)
| | | | - Iryna Entfellner
- Institute for Molecular Biosciences, University of Graz, Graz, Austria
| | | | - Thomas Kickenweiz
- Institute for Molecular Biosciences, University of Graz, Graz, Austria
| | - Slaven Stekovic
- Institute for Molecular Biosciences, University of Graz, Graz, Austria
| | | | - Christian Schmid
- Institute for Molecular Biosciences, University of Graz, Graz, Austria
| | - Lisa Klug
- Institute for Molecular Biosciences, University of Graz, Graz, Austria
| | - Alice G. Sorgo
- Institute for Molecular Biosciences, University of Graz, Graz, Austria
| | - Tobias Eisenberg
- Institute for Molecular Biosciences, University of Graz, Graz, Austria
| | - Sabrina Büttner
- Institute for Molecular Biosciences, University of Graz, Graz, Austria
| | - Guillermo Mariño
- INSERM, U848, Villejuif, France
- Institut Gustave Roussy, Villejuif, France
- Université Paris Sud, Paris 11, Villejuif, France
| | - Rafal Koziel
- Institute for Biomedical Aging Research (IBA), Austrian Academy of Sciences, Innsbruck, Austria
| | - Pidder Jansen-Dürr
- Institute for Biomedical Aging Research (IBA), Austrian Academy of Sciences, Innsbruck, Austria
| | - Kai-Uwe Fröhlich
- Institute for Molecular Biosciences, University of Graz, Graz, Austria
| | - Guido Kroemer
- INSERM, U848, Villejuif, France
- Institut Gustave Roussy, Villejuif, France
- Metabolomics Platform, Institut Gustave Roussy, Villejuif, France
- Centre de Recherche des Cordeliers, Paris, France
- Pôle de Biologie, Hôpital Européen Georges Pompidou, AP-HP, Paris, France
- Université Paris Descartes, Paris 5, Paris, France
| | - Frank Madeo
- Institute for Molecular Biosciences, University of Graz, Graz, Austria
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45
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GPI (glycosylphosphatidylinositol)-linked aspartyl proteases regulate vacuole homoeostasis in Candida glabrata. Biochem J 2014; 458:323-34. [PMID: 24341558 DOI: 10.1042/bj20130757] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
A family of 11 GPI (glycosylphosphatidylinositol)-linked cell surface-associated aspartyl proteases (yapsins) in the human opportunistic fungal pathogen Candida glabrata is required for cell wall remodelling, pH homoeostasis, survival in macrophages and virulence in a murine model of disseminated candidiasis. In the present paper, we report new roles for yapsins in C. glabrata physiology and implicate them for the first time in the regulation of vacuole homoeostasis. In the present study we show that a C. glabrata mutant lacking all 11 yapsins, Cgyps1-11∆, possesses an enlarged vacuole and displays vma- (vacuolar membrane ATPase)-like phenotypes with elevated metal ion susceptibility in an alkaline pH medium and diminished Vma activity. The results of the present study also demonstrate a singular role for CgYps1 (C. glabrata yapsin 1) in the maintenance of ion homoeostasis under normal and calcineurin-inhibited conditions. Elevated polyphosphate levels and diminished cellular CPY (carboxypeptidase Y) activity in the Cgyps1-11∆ mutant highlight the yapsin requirement for a properly functioning vacuole. Lastly, a gross perturbation of cellular homoeostasis in the Cgyps1-11∆ mutant, even in the absence of external stressors, characterized by reduced levels of ATP and stress metabolites, elevated ROS (reactive oxygen species) levels, cell surface abnormalities, and a constitutively activated PKC (protein kinase C) signalling pathway underscore diverse physiological functions of yapsins in C. glabrata.
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46
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Saccharomyces cerevisiae vacuolar H+-ATPase regulation by disassembly and reassembly: one structure and multiple signals. EUKARYOTIC CELL 2014; 13:706-14. [PMID: 24706019 DOI: 10.1128/ec.00050-14] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Vacuolar H(+)-ATPases (V-ATPases) are highly conserved ATP-driven proton pumps responsible for acidification of intracellular compartments. V-ATPase proton transport energizes secondary transport systems and is essential for lysosomal/vacuolar and endosomal functions. These dynamic molecular motors are composed of multiple subunits regulated in part by reversible disassembly, which reversibly inactivates them. Reversible disassembly is intertwined with glycolysis, the RAS/cyclic AMP (cAMP)/protein kinase A (PKA) pathway, and phosphoinositides, but the mechanisms involved are elusive. The atomic- and pseudo-atomic-resolution structures of the V-ATPases are shedding light on the molecular dynamics that regulate V-ATPase assembly. Although all eukaryotic V-ATPases may be built with an inherent capacity to reversibly disassemble, not all do so. V-ATPase subunit isoforms and their interactions with membrane lipids and a V-ATPase-exclusive chaperone influence V-ATPase assembly. This minireview reports on the mechanisms governing reversible disassembly in the yeast Saccharomyces cerevisiae, keeping in perspective our present understanding of the V-ATPase architecture and its alignment with the cellular processes and signals involved.
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47
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Molin M, Demir AB. Linking Peroxiredoxin and Vacuolar-ATPase Functions in Calorie Restriction-Mediated Life Span Extension. Int J Cell Biol 2014; 2014:913071. [PMID: 24639875 PMCID: PMC3930189 DOI: 10.1155/2014/913071] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2013] [Revised: 11/11/2013] [Accepted: 12/15/2013] [Indexed: 01/09/2023] Open
Abstract
Calorie restriction (CR) is an intervention extending the life spans of many organisms. The mechanisms underlying CR-dependent retardation of aging are still poorly understood. Despite mechanisms involving conserved nutrient signaling pathways proposed, few target processes that can account for CR-mediated longevity have so far been identified. Recently, both peroxiredoxins and vacuolar-ATPases were reported to control CR-mediated retardation of aging downstream of conserved nutrient signaling pathways. In this review, we focus on peroxiredoxin-mediated stress-defence and vacuolar-ATPase regulated acidification and pinpoint common denominators between the two mechanisms proposed for how CR extends life span. Both the activities of peroxiredoxins and vacuolar-ATPases are stimulated upon CR through reduced activities in conserved nutrient signaling pathways and both seem to stimulate cellular resistance to peroxide-stress. However, whereas vacuolar-ATPases have recently been suggested to control both Ras-cAMP-PKA- and TORC1-mediated nutrient signaling, neither the physiological benefits of a proposed role for peroxiredoxins in H2O2-signaling nor downstream targets regulated are known. Both peroxiredoxins and vacuolar-ATPases do, however, impinge on mitochondrial iron-metabolism and further characterization of their impact on iron homeostasis and peroxide-resistance might therefore increase our understanding of the beneficial effects of CR on aging and age-related diseases.
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Affiliation(s)
- Mikael Molin
- Department of Chemistry and Molecular Biology, University of Gothenburg, Medicinaregatan 9C, 413 90 Gothenburg, Sweden
| | - Ayse Banu Demir
- Department of Chemistry and Molecular Biology, University of Gothenburg, Medicinaregatan 9C, 413 90 Gothenburg, Sweden
- Department of Molecular Biology and Genetics, Izmir Institute of Technology, 35430 Urla, Izmir, Turkey
- Department of Oncology, Institute of Oncology, Dokuz Eylul University, 35340 Inciralti, Izmir, Turkey
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48
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Hayek SR, Lee SA, Parra KJ. Advances in targeting the vacuolar proton-translocating ATPase (V-ATPase) for anti-fungal therapy. Front Pharmacol 2014; 5:4. [PMID: 24478704 PMCID: PMC3902353 DOI: 10.3389/fphar.2014.00004] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2013] [Accepted: 01/06/2014] [Indexed: 11/13/2022] Open
Abstract
Vacuolar proton-translocating ATPase (V-ATPase) is a membrane-bound, multi-subunit enzyme that uses the energy of ATP hydrolysis to pump protons across membranes. V-ATPase activity is critical for pH homeostasis and organelle acidification as well as for generation of the membrane potential that drives secondary transporters and cellular metabolism. V-ATPase is highly conserved across species and is best characterized in the model fungus Saccharomyces cerevisiae. However, recent studies in mammals have identified significant alterations from fungi, particularly in the isoform composition of the 14 subunits and in the regulation of complex disassembly. These differences could be exploited for selectivity between fungi and humans and highlight the potential for V-ATPase as an anti-fungal drug target. Candida albicans is a major human fungal pathogen and causes fatality in 35% of systemic infections, even with anti-fungal treatment. The pathogenicity of C. albicans correlates with environmental, vacuolar, and cytoplasmic pH regulation, and V-ATPase appears to play a fundamental role in each of these processes. Genetic loss of V-ATPase in pathogenic fungi leads to defective virulence, and a comprehensive picture of the mechanisms involved is emerging. Recent studies have explored the practical utility of V-ATPase as an anti-fungal drug target in C. albicans, including pharmacological inhibition, azole therapy, and targeting of downstream pathways. This overview will discuss these studies as well as hypothetical ways to target V-ATPase and novel high-throughput methods for use in future drug discovery screens.
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Affiliation(s)
- Summer R Hayek
- Department of Biochemistry and Molecular Biology, School of Medicine, University of New Mexico Health Sciences Center Albuquerque, NM, USA
| | - Samuel A Lee
- Department of Internal Medicine, School of Medicine, University of New Mexico Health Sciences Center Albuquerque, NM, USA ; Section of Infectious Diseases, New Mexico Veterans Healthcare System Albuquerque, NM, USA
| | - Karlett J Parra
- Department of Biochemistry and Molecular Biology, School of Medicine, University of New Mexico Health Sciences Center Albuquerque, NM, USA
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49
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Vacuolar H+-ATPase: An Essential Multitasking Enzyme in Physiology and Pathophysiology. ACTA ACUST UNITED AC 2014. [DOI: 10.1155/2014/675430] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Vacuolar H+-ATPases (V-ATPases) are large multisubunit proton pumps that are required for housekeeping acidification of membrane-bound compartments in eukaryotic cells. Mammalian V-ATPases are composed of 13 different subunits. Their housekeeping functions include acidifying endosomes, lysosomes, phagosomes, compartments for uncoupling receptors and ligands, autophagosomes, and elements of the Golgi apparatus. Specialized cells, including osteoclasts, intercalated cells in the kidney and pancreatic beta cells, contain both the housekeeping V-ATPases and an additional subset of V-ATPases, which plays a cell type specific role. The specialized V-ATPases are typically marked by the inclusion of cell type specific isoforms of one or more of the subunits. Three human diseases caused by mutations of isoforms of subunits have been identified. Cancer cells utilize V-ATPases in unusual ways; characterization of V-ATPases may lead to new therapeutic modalities for the treatment of cancer. Two accessory proteins to the V-ATPase have been identified that regulate the proton pump. One is the (pro)renin receptor and data is emerging that indicates that V-ATPase may be intimately linked to renin/angiotensin signaling both systemically and locally. In summary, V-ATPases play vital housekeeping roles in eukaryotic cells. Specialized versions of the pump are required by specific organ systems and are involved in diseases.
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Smardon AM, Diab HI, Tarsio M, Diakov TT, Nasab ND, West RW, Kane PM. The RAVE complex is an isoform-specific V-ATPase assembly factor in yeast. Mol Biol Cell 2013; 25:356-67. [PMID: 24307682 PMCID: PMC3907276 DOI: 10.1091/mbc.e13-05-0231] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Vacuolar H+-ATPases (V-ATPases) acidify multiple organelles, and subunit isoforms help impart organelle-specific regulation of acidification. The regulator of ATPase of vacuoles and endosomes (RAVE) complex regulates organelle acidification by promoting V-ATPase assembly. This work demonstrates that RAVE is the first identified isoform-specific V-ATPase assembly factor required for control of vacuolar acidification. The regulator of ATPase of vacuoles and endosomes (RAVE) complex is implicated in vacuolar H+-translocating ATPase (V-ATPase) assembly and activity. In yeast, rav1∆ mutants exhibit a Vma− growth phenotype characteristic of loss of V-ATPase activity only at high temperature. Synthetic genetic analysis identified mutations that exhibit a full, temperature-independent Vma− growth defect when combined with the rav1∆ mutation. These include class E vps mutations, which compromise endosomal sorting. The synthetic Vma− growth defect could not be attributed to loss of vacuolar acidification in the double mutants, as there was no vacuolar acidification in the rav1∆ mutant. The yeast V-ATPase a subunit is present as two isoforms, Stv1p in Golgi and endosomes and Vph1p in vacuoles. Rav1p interacts directly with the N-terminal domain of Vph1p. STV1 overexpression suppressed the growth defects of both rav1∆ and rav1∆vph1∆, and allowed RAVE-independent assembly of active Stv1p-containing V-ATPases in vacuoles. Mutations causing synthetic genetic defects in combination with rav1∆ perturbed the normal localization of Stv1–green fluorescent protein. We propose that RAVE is necessary for assembly of Vph1-containing V-ATPase complexes but not Stv1-containing complexes. Synthetic Vma− phenotypes arise from defects in Vph1p-containing complexes caused by rav1∆, combined with defects in Stv1p-containing V-ATPases caused by the second mutation. Thus RAVE is the first isoform-specific V-ATPase assembly factor.
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Affiliation(s)
- Anne M Smardon
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY 13210
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