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Hashmi F, Kane PM. V-ATPase Disassembly at the Yeast Lysosome-Like Vacuole Is a Phenotypic Driver of Lysosome Dysfunction in Replicative Aging. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.23.604825. [PMID: 39091794 PMCID: PMC11291124 DOI: 10.1101/2024.07.23.604825] [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: 08/04/2024]
Abstract
Declines in lysosomal acidification and function with aging are observed in organisms ranging from yeast to humans. V-ATPases play a central role in organelle acidification and V-ATPase activity is regulated by reversible disassembly in many different settings. Using the yeast Saccharomyces cerevisiae as a replicative aging model, we demonstrate that V-ATPases disassemble into their V1 and V0 subcomplexes in aging cells, with release of V1 subunit C (Vma5) from the lysosome-like vacuole into the cytosol. Disassembly is observed after ≥5 cell divisions and results in overall vacuole alkalinization. Caloric restriction, an established mechanism for reversing many age-related outcomes, prevents V-ATPase disassembly in older cells and preserves vacuolar pH homeostasis. Reversible disassembly is controlled in part by the activity of two opposing and conserved factors, the RAVE complex and Oxr1. The RAVE complex promotes V-ATPase assembly and a rav1Δ mutant shortens replicative lifespan; Oxr1 promotes disassembly and an oxr1Δ mutation extends lifespan. Importantly, the level of Rav2, a key subunit of the RAVE complex, declines in aged cells. These data indicate that reduced V-ATPase assembly contributes to the loss of lysosome acidification with age, which affects replicative lifespan.
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Affiliation(s)
- Fiza Hashmi
- Department of Biochemistry and Molecular Biology , SUNY Upstate Medical University, Syracuse, NY USA
| | - Patricia M Kane
- Department of Biochemistry and Molecular Biology , SUNY Upstate Medical University, Syracuse, NY USA
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Oot RA, Wilkens S. Human V-ATPase function is positively and negatively regulated by TLDc proteins. Structure 2024; 32:989-1000.e6. [PMID: 38593795 PMCID: PMC11246223 DOI: 10.1016/j.str.2024.03.009] [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: 11/09/2023] [Revised: 02/23/2024] [Accepted: 03/13/2024] [Indexed: 04/11/2024]
Abstract
Proteins that contain a highly conserved TLDc domain (Tre2/Bub2/Cdc16 LysM domain catalytic) offer protection against oxidative stress and are widely implicated in neurological health and disease. How this family of proteins exerts their function, however, is poorly understood. We have recently found that the yeast TLDc protein, Oxr1p, inhibits the proton pumping vacuolar ATPase (V-ATPase) by inducing disassembly of the pump. While loss of TLDc protein function in mammals shares disease phenotypes with V-ATPase defects, whether TLDc proteins impact human V-ATPase activity directly is unclear. Here we examine the effects of five human TLDc proteins, TLDC2, NCOA7, OXR1, TBC1D24, and mEAK7 on the activity of the human V-ATPase. We find that while TLDC2, TBC1D24, and the TLDc domains of OXR1 and NCOA7 inhibit V-ATPase by inducing enzyme disassembly, mEAK7 activates the pump. The data thus shed new light both on mammalian TLDc protein function and V-ATPase regulation.
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Affiliation(s)
- Rebecca A Oot
- Department of Biochemistry & Molecular Biology, SUNY Upstate Medical University, Syracuse, NY 13210, USA.
| | - Stephan Wilkens
- Department of Biochemistry & Molecular Biology, SUNY Upstate Medical University, Syracuse, NY 13210, USA
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3
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Eaton AF, Danielson EC, Capen D, Merkulova M, Brown D. Dmxl1 Is an Essential Mammalian Gene that Is Required for V-ATPase Assembly and Function In Vivo. FUNCTION 2024; 5:zqae025. [PMID: 38984989 PMCID: PMC11237898 DOI: 10.1093/function/zqae025] [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: 04/16/2024] [Revised: 05/10/2024] [Accepted: 05/13/2024] [Indexed: 07/11/2024] Open
Abstract
The proton pumping V-ATPase drives essential biological processes, such as acidification of intracellular organelles. Critically, the V-ATPase domains, V1 and VO, must assemble to produce a functional holoenzyme. V-ATPase dysfunction results in cancer, neurodegeneration, and diabetes, as well as systemic acidosis caused by reduced activity of proton-secreting kidney intercalated cells (ICs). However, little is known about the molecular regulation of V-ATPase in mammals. We identified a novel interactor of the mammalian V-ATPase, Drosophila melanogaster X chromosomal gene-like 1 (Dmxl1), aka Rabconnectin-3A. The yeast homologue of Dmxl1, Rav1p, is part of a complex that catalyzes the reversible assembly of the domains. We, therefore,hypothesized that Dmxl1 is a mammalian V-ATPase assembly factor. Here, we generated kidney IC-specific Dmxl1 knockout (KO) mice, which had high urine pH, like B1 V-ATPase KO mice, suggesting impaired V-ATPase function. Western blotting showed decreased B1 expression and B1 (V1) and a4 (VO) subunits were more intracellular and less colocalized in Dmxl1 KO ICs. In parallel, subcellular fractionation revealed less V1 associated B1 in the membrane fraction of KO cells relative to the cytosol. Furthermore, a proximity ligation assay performed using probes against B1 and a4 V-ATPase subunits also revealed decreased association. We propose that loss of Dmxl1 reduces V-ATPase holoenzyme assembly, thereby inhibiting proton pumping function. Dmxl1 may recruit the V1 domain to the membrane and facilitate assembly with the VO domain and in its absence V1 may be targeted for degradation. We conclude that Dmxl1 is a bona fide mammalian V-ATPase assembly factor.
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Affiliation(s)
- Amity F Eaton
- Program in Membrane Biology and Division of Nephrology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
| | - Elizabeth C Danielson
- Program in Membrane Biology and Division of Nephrology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
| | - Diane Capen
- Program in Membrane Biology and Division of Nephrology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
| | - Maria Merkulova
- Program in Membrane Biology and Division of Nephrology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
| | - Dennis Brown
- Program in Membrane Biology and Division of Nephrology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
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Wang N, Ren L, Danser AHJ. Vacuolar H +-ATPase in Diabetes, Hypertension, and Atherosclerosis. Microcirculation 2024; 31:e12855. [PMID: 38683673 DOI: 10.1111/micc.12855] [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: 02/07/2024] [Revised: 03/29/2024] [Accepted: 04/15/2024] [Indexed: 05/02/2024]
Abstract
Vacuolar H+-ATPase (V-ATPase) is a multisubunit protein complex which, along with its accessory proteins, resides in almost every eukaryotic cell. It acts as a proton pump and as such is responsible for regulating pH in lysosomes, endosomes, and the extracellular space. Moreover, V-ATPase has been implicated in receptor-mediated signaling. Although numerous studies have explored the role of V-ATPase in cancer, osteoporosis, and neurodegenerative diseases, research on its involvement in vascular disease remains limited. Vascular diseases pose significant challenges to human health. This review aimed to shed light on the role of V-ATPase in hypertension and atherosclerosis. Furthermore, given that vascular complications are major complications of diabetes, this review also discusses the pathways through which V-ATPase may contribute to such complications. Beginning with an overview of the structure and function of V-ATPase in hypertension, atherosclerosis, and diabetes, this review ends by exploring the pharmacological potential of targeting V-ATPase.
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Affiliation(s)
- Na Wang
- Division of Vascular Medicine and Pharmacology, Department of Internal Medicine, Erasmus MC, Rotterdam, The Netherlands
- Clinical Research Center, The First Affiliated Hospital of Shantou University Medical College, Shantou, China
| | - Liwei Ren
- Division of Vascular Medicine and Pharmacology, Department of Internal Medicine, Erasmus MC, Rotterdam, The Netherlands
- Department of Pharmacy, Shenzhen People's Hospital (The Second Clinical Medical College, Jinan University, The First Affiliated Hospital, Southern University of Science and Technology), Shenzhen, China
| | - A H Jan Danser
- Division of Vascular Medicine and Pharmacology, Department of Internal Medicine, Erasmus MC, Rotterdam, The Netherlands
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Mo S, Liu T, Zhou H, Huang J, Zhao L, Lu F, Kuang Y. ATP6V1B1 regulates ovarian cancer progression and cisplatin sensitivity through the mTOR/autophagy pathway. Mol Cell Biochem 2024:10.1007/s11010-024-05025-w. [PMID: 38735913 DOI: 10.1007/s11010-024-05025-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2024] [Accepted: 05/02/2024] [Indexed: 05/14/2024]
Abstract
Early detection and effective chemotherapy for ovarian cancer, a serious gynecological malignancy, require further progress. This study aimed to investigate the molecular mechanism of ATPase H+-Transporting V1 Subunit B1 (ATP6V1B1) in ovarian cancer development and chemoresistance. Our data show that ATP6V1B1 is upregulated in ovarian cancer and correlated with decreased progression-free survival. Gain- and loss-of-function experiments demonstrated that ATP6V1B1 promotes the proliferation, migration, and invasion of ovarian cancer cells in vitro, while ATP6V1B1 knockout inhibits tumor growth in vivo. In addition, knocking down ATP6V1B1 increases the sensitivity of ovarian cancer cells to cisplatin. Mechanistic studies showed that ATP6V1B1 regulates the activation of the mTOR/autophagy pathway. Overall, our study confirmed the oncogenic role of ATP6V1B1 in ovarian cancer and revealed that ATP6V1B1 promotes ovarian cancer progression via the mTOR/autophagy axis.
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Affiliation(s)
- Shien Mo
- Department of Gynecology, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China
- Key Laboratory of Early Prevention and Treatment for Regional High Frequency Tumor, Gaungxi Medical University, Ministry of Education, Nanning, Guangxi, China
- Guangxi Key Laboratory of High-Incidence-Tumor Prevention & Treatment, Guangxi Medical University, Nanning, Guangxi, China
| | - Tingji Liu
- Department of Gynecology, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China
| | - Haiqin Zhou
- Department of Gynecology, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China
- Key Laboratory of Early Prevention and Treatment for Regional High Frequency Tumor, Gaungxi Medical University, Ministry of Education, Nanning, Guangxi, China
- Guangxi Key Laboratory of High-Incidence-Tumor Prevention & Treatment, Guangxi Medical University, Nanning, Guangxi, China
| | - Junning Huang
- Department of Gynecology, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China
| | - Ling Zhao
- Department of Gynecology, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China
| | - Fangfang Lu
- Department of Gynecology, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China
| | - Yan Kuang
- Department of Gynecology, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China.
- Key Laboratory of Early Prevention and Treatment for Regional High Frequency Tumor, Gaungxi Medical University, Ministry of Education, Nanning, Guangxi, China.
- Guangxi Key Laboratory of High-Incidence-Tumor Prevention & Treatment, Guangxi Medical University, Nanning, Guangxi, China.
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Mulligan RJ, Magaj MM, Digilio L, Redemann S, Yap CC, Winckler B. Collapse of late endosomal pH elicits a rapid Rab7 response via the V-ATPase and RILP. J Cell Sci 2024; 137:jcs261765. [PMID: 38578235 PMCID: PMC11166203 DOI: 10.1242/jcs.261765] [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: 11/02/2023] [Accepted: 03/26/2024] [Indexed: 04/06/2024] Open
Abstract
Endosomal-lysosomal trafficking is accompanied by the acidification of endosomal compartments by the H+-V-ATPase to reach low lysosomal pH. Disruption of the correct pH impairs lysosomal function and the balance of protein synthesis and degradation (proteostasis). Here, we treated mammalian cells with the small dipeptide LLOMe, which is known to permeabilize lysosomal membranes, and find that LLOMe also impacts late endosomes (LEs) by neutralizing their pH without causing membrane permeabilization. We show that LLOMe leads to hyperactivation of Rab7 (herein referring to Rab7a), and disruption of tubulation and mannose-6-phosphate receptor (CI-M6PR; also known as IGF2R) recycling on pH-neutralized LEs. pH neutralization (NH4Cl) and expression of Rab7 hyperactive mutants alone can both phenocopy the alterations in tubulation and CI-M6PR trafficking. Mechanistically, pH neutralization increases the assembly of the V1G1 subunit (encoded by ATP6V1G1) of the V-ATPase on endosomal membranes, which stabilizes GTP-bound Rab7 via RILP, a known interactor of Rab7 and V1G1. We propose a novel pathway by which V-ATPase and RILP modulate LE pH and Rab7 activation in concert. This pathway might broadly contribute to pH control during physiologic endosomal maturation or starvation and during pathologic pH neutralization, which occurs via lysosomotropic compounds and in disease states.
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Affiliation(s)
- Ryan J. Mulligan
- Department of Cell Biology, University of Virginia, Charlottesville, VA 22908, USA
- Cell and Developmental Biology Graduate Program, University of Virginia, Charlottesville, VA 22908, USA
- Medical Scientist Training Program, University of Virginia, Charlottesville, VA 22908, USA
| | - Magdalena M. Magaj
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA 22908, USA
- Cell and Developmental Biology Graduate Program, University of Virginia, Charlottesville, VA 22908, USA
| | - Laura Digilio
- Department of Cell Biology, University of Virginia, Charlottesville, VA 22908, USA
| | - Stefanie Redemann
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA 22908, USA
- Center for Membrane and Cell Physiology, University of Virginia, Charlottesville, VA 22908, USA
| | - Chan Choo Yap
- Department of Cell Biology, University of Virginia, Charlottesville, VA 22908, USA
| | - Bettina Winckler
- Department of Cell Biology, University of Virginia, Charlottesville, VA 22908, USA
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Khan MM, Wilkens S. Molecular mechanism of Oxr1p mediated disassembly of yeast V-ATPase. EMBO Rep 2024; 25:2323-2347. [PMID: 38565737 PMCID: PMC11094088 DOI: 10.1038/s44319-024-00126-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2023] [Revised: 03/07/2024] [Accepted: 03/09/2024] [Indexed: 04/04/2024] Open
Abstract
The eukaryotic vacuolar H+-ATPase (V-ATPase) is regulated by reversible disassembly into autoinhibited V1-ATPase and Vo proton channel subcomplexes. We recently reported that the TLDc protein Oxr1p induces V-ATPase disassembly in vitro. Whether and how Oxr1p is involved in enzyme disassembly in vivo, however, is not known. Here, using yeast genetics and fluorescence microscopy, we show that Oxr1p is essential for efficient V-ATPase disassembly in the cell. Supporting biochemical and biophysical in vitro experiments show that whereas Oxr1p-driven holoenzyme disassembly can occur in the absence of nucleotides, the presence of ATP greatly accelerates the process. ATP hydrolysis is needed, however, for subsequent release of Oxr1p so that the free V1 can adopt the autoinhibited conformation. Overall, our study unravels the molecular mechanism of Oxr1p-induced disassembly that occurs in vivo as part of the canonical V-ATPase regulation by reversible disassembly.
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Affiliation(s)
- Md Murad Khan
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, 13210, USA
| | - Stephan Wilkens
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, 13210, USA.
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8
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Sava I, Davis LJ, Gray SR, Bright NA, Luzio JP. Reversible assembly and disassembly of V-ATPase during the lysosome regeneration cycle. Mol Biol Cell 2024; 35:ar63. [PMID: 38446621 PMCID: PMC11151095 DOI: 10.1091/mbc.e23-08-0322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Revised: 02/23/2024] [Accepted: 03/01/2024] [Indexed: 03/08/2024] Open
Abstract
Regulation of the luminal pH of late endocytic compartments in continuously fed mammalian cells is poorly understood. Using normal rat kidney fibroblasts, we investigated the reversible assembly/disassembly of the proton pumping V-ATPase when endolysosomes are formed by kissing and fusion of late endosomes with lysosomes and during the subsequent reformation of lysosomes. We took advantage of previous work showing that sucrosomes formed by the uptake of sucrose are swollen endolysosomes from which lysosomes are reformed after uptake of invertase. Using confocal microscopy and subcellular fractionation of NRK cells stably expressing fluorescently tagged proteins, we found net recruitment of the V1 subcomplex during sucrosome formation and loss during lysosome reformation, with a similar time course to RAB7a loss. Addition of invertase did not alter mTORC1 signalling, suggesting that the regulation of reversible V-ATPase assembly/disassembly in continuously fed cells differs from that in cells subject to amino acid depletion/refeeding. Using live cell microscopy, we demonstrated recruitment of a fluorescently tagged V1 subunit during endolysosome formation and a dynamic equilibrium and rapid exchange between the cytosolic and membrane bound pools of this subunit. We conclude that reversible V-ATPase assembly/disassembly plays a key role in regulating endolysosomal/lysosomal pH in continuously fed cells.
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Affiliation(s)
- Ioana Sava
- Cambridge Institute for Medical Research (CIMR) and Department of Clinical Biochemistry, University of Cambridge School of Clinical Medicine, The Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0XY, UK
| | - Luther J. Davis
- Cambridge Institute for Medical Research (CIMR) and Department of Clinical Biochemistry, University of Cambridge School of Clinical Medicine, The Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0XY, UK
| | - Sally R. Gray
- Cambridge Institute for Medical Research (CIMR) and Department of Clinical Biochemistry, University of Cambridge School of Clinical Medicine, The Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0XY, UK
| | - Nicholas A. Bright
- Cambridge Institute for Medical Research (CIMR) and Department of Clinical Biochemistry, University of Cambridge School of Clinical Medicine, The Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0XY, UK
| | - J. Paul Luzio
- Cambridge Institute for Medical Research (CIMR) and Department of Clinical Biochemistry, University of Cambridge School of Clinical Medicine, The Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0XY, UK
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Choi C, Jeong YL, Park KM, Kim M, Kim S, Jo H, Lee S, Kim H, Choi G, Choi YH, Seong JK, Namgoong S, Chung Y, Jung YS, Granneman JG, Hyun YM, Kim JK, Lee YH. TM4SF19-mediated control of lysosomal activity in macrophages contributes to obesity-induced inflammation and metabolic dysfunction. Nat Commun 2024; 15:2779. [PMID: 38555350 PMCID: PMC10981689 DOI: 10.1038/s41467-024-47108-8] [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: 10/17/2023] [Accepted: 03/20/2024] [Indexed: 04/02/2024] Open
Abstract
Adipose tissue (AT) adapts to overnutrition in a complex process, wherein specialized immune cells remove and replace dysfunctional and stressed adipocytes with new fat cells. Among immune cells recruited to AT, lipid-associated macrophages (LAMs) have emerged as key players in obesity and in diseases involving lipid stress and inflammation. Here, we show that LAMs selectively express transmembrane 4 L six family member 19 (TM4SF19), a lysosomal protein that represses acidification through its interaction with Vacuolar-ATPase. Inactivation of TM4SF19 elevates lysosomal acidification and accelerates the clearance of dying/dead adipocytes in vitro and in vivo. TM4SF19 deletion reduces the LAM accumulation and increases the proportion of restorative macrophages in AT of male mice fed a high-fat diet. Importantly, male mice lacking TM4SF19 adapt to high-fat feeding through adipocyte hyperplasia, rather than hypertrophy. This adaptation significantly improves local and systemic insulin sensitivity, and energy expenditure, offering a potential avenue to combat obesity-related metabolic dysfunction.
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Affiliation(s)
- Cheoljun Choi
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul, 08826, Republic of Korea
| | - Yujin L Jeong
- Department of Life Sciences, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Koung-Min Park
- Department of Anatomy and Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Minji Kim
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul, 08826, Republic of Korea
| | - Sangseob Kim
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul, 08826, Republic of Korea
| | - Honghyun Jo
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul, 08826, Republic of Korea
| | - Sumin Lee
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul, 08826, Republic of Korea
| | - Heeseong Kim
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul, 08826, Republic of Korea
| | - Garam Choi
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul, 08826, Republic of Korea
| | - Yoon Ha Choi
- Department of Life Sciences, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Je Kyung Seong
- Korea Mouse Phenotyping Center (KMPC), and Laboratory of Developmental Biology and Genomics, College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea
| | - Sik Namgoong
- Department of Plastic Surgery, Korea University College of Medicine, Seoul, Republic of Korea
| | - Yeonseok Chung
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul, 08826, Republic of Korea
| | - Young-Suk Jung
- Department of Pharmacy, College of Pharmacy, Research Institute for Drug Development, Pusan National University, Busan, Republic of Korea.
| | - James G Granneman
- Center for Molecular Medicine and Genetics, Wayne State University, Detroit, MI, USA.
| | - Young-Min Hyun
- Department of Anatomy and Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul, Republic of Korea.
| | - Jong Kyoung Kim
- Department of Life Sciences, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea.
| | - Yun-Hee Lee
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul, 08826, Republic of Korea.
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Liu L, Chen X, Wu L, Huang K, Wang Z, Zheng Y, Zheng C, Zhang Z, Chen J, Wei J, Chen S, Jin W, Chen J, Wei D, Xu Y. Ubiquitin ligase subunit FBXO9 inhibits V-ATPase assembly and impedes lung cancer metastasis. Exp Hematol Oncol 2024; 13:32. [PMID: 38486234 PMCID: PMC10938814 DOI: 10.1186/s40164-024-00497-4] [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: 11/26/2023] [Accepted: 02/29/2024] [Indexed: 03/18/2024] Open
Abstract
BACKGROUND The evolutionarily conserved protein FBXO9 acts as a substrate receptor for the SKP1-cullin-1-RBX1 ubiquitin ligase and is implicated in cancer, exhibiting either tumor-suppressive or oncogenic effects depending on the specific tumor type. However, their role in lung cancer metastasis remains unclear. METHODS Lentiviral vectors carrying miRNA-based shRNA sequences for gene-specific knockdown were generated, and Lenti-CRISPR-Cas9 vectors containing gene-specific sgRNA sequences were designed. Gene overexpression was achieved using doxycycline-inducible lentiviral constructs, while gene knockdown or knockout cells were generated using shRNA and CRISPR-Cas9, respectively. Functional assays included migration, clonogenic survival assays, tumor sphere assays, and protein interaction studies using mass spectrometry, immunoprecipitation, and immunoblot analysis. RESULTS This study identified FBXO9 as a crucial regulator that suppresses lung cancer cell migration, tumor sphere growth and restricts metastasis. We showed that FBXO9 facilitates the ubiquitination of the catalytic subunit A (ATP6V1A) of the Vacuolar-type H+-ATPase (V-ATPase), resulting in its interaction with the cytoplasmic chaperone HSPA8 and subsequent sequestration within the cytoplasm. This process hinders the assembly of functional V-ATPase, resulting in reduced vesicular acidification. In contrast, depletion of FBXO9 reduced ATP6V1A ubiquitination, resulting in increased V-ATPase assembly and vesicular acidification, thus promoting pro-metastatic Wnt signaling and metastasis of lung cancer cells. Furthermore, we demonstrated the effectiveness of inhibitors targeting V-ATPase in inhibiting lung cancer metastasis in a mouse model. Finally, we established a correlation between lower FBXO9 levels and poorer survival outcomes in patients with lung cancer. CONCLUSION These findings collectively elucidate the critical role of FBXO9 in regulating V-ATPase assembly and provide a molecular basis for FBXO9's function in inhibiting lung cancer metastasis. This highlights the potential therapeutic opportunities of FBXO9 supplementation.
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Affiliation(s)
- Liang Liu
- Department of Radiation Oncology, Shanghai Pulmonary Hospital, School of Medicine, Tongji University, Shanghai, 200433, China
- Institute of Clinical Medicine, Zhongshan Hospital, Fudan University, Shanghai, 200032, China
| | - Xiaodong Chen
- Department of General Surgery, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, 325015, Zhejiang Province, China
| | - Leilei Wu
- Department of Radiation Oncology, Shanghai Pulmonary Hospital, School of Medicine, Tongji University, Shanghai, 200433, China
| | - Kaizong Huang
- Department of Clinical Pharmacology Lab, Nanjing First Hospital, Nanjing Medical University, Nanjing, 210006, China
| | - Zhenyi Wang
- Medical Research Center, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, 325015, Zhejiang Province, China
| | - Yaolin Zheng
- Department of Oncology, Nanjing First Hospital, Nanjing Medical University, Nanjing, 210006, China
| | - Cheng Zheng
- Medical Research Center, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, 325015, Zhejiang Province, China
| | - Zhenshan Zhang
- Department of Radiation Oncology, Shanghai Proton and Heavy Ion Center, Fudan University Cancer Center, Shanghai, 200032, China
| | - Jiayan Chen
- Department of Radiation Oncology, Fudan University Shanghai Cancer Center, Shanghai, 200032, China
| | - Jiaming Wei
- Institute of Medicinal Biotechnology, Jiangsu College of Nursing, Huai'an, 223300, Jiangsu, China
| | - Song Chen
- Institute of Medicinal Biotechnology, Jiangsu College of Nursing, Huai'an, 223300, Jiangsu, China
- Translational Research Institute, Henan Provincial People's Hospital, Academy of Medical Sciences, Zhengzhou University, Zhengzhou, 450053, Henan, China
| | - Weilin Jin
- Institute of Cancer Neuroscience, Medical Frontier Innovation Research Center, The First Hospital of Lanzhou University, The First Clinical Medical College of Lanzhou University, Lanzhou, 730000, China
| | - Jinfei Chen
- Department of Oncology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, 730000, Zhejiang Province, China
| | - Dongping Wei
- Medical Research Center, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, 325015, Zhejiang Province, China.
- Department of Oncology, Nanjing First Hospital, Nanjing Medical University, Nanjing, 210006, China.
| | - Yaping Xu
- Department of Radiation Oncology, Shanghai Pulmonary Hospital, School of Medicine, Tongji University, Shanghai, 200433, China.
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11
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Settembre C, Perera RM. Lysosomes as coordinators of cellular catabolism, metabolic signalling and organ physiology. Nat Rev Mol Cell Biol 2024; 25:223-245. [PMID: 38001393 DOI: 10.1038/s41580-023-00676-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/29/2023] [Indexed: 11/26/2023]
Abstract
Every cell must satisfy basic requirements for nutrient sensing, utilization and recycling through macromolecular breakdown to coordinate programmes for growth, repair and stress adaptation. The lysosome orchestrates these key functions through the synchronised interplay between hydrolytic enzymes, nutrient transporters and signalling factors, which together enable metabolic coordination with other organelles and regulation of specific gene expression programmes. In this Review, we discuss recent findings on lysosome-dependent signalling pathways, focusing on how the lysosome senses nutrient availability through its physical and functional association with mechanistic target of rapamycin complex 1 (mTORC1) and how, in response, the microphthalmia/transcription factor E (MiT/TFE) transcription factors exert feedback regulation on lysosome biogenesis. We also highlight the emerging interactions of lysosomes with other organelles, which contribute to cellular homeostasis. Lastly, we discuss how lysosome dysfunction contributes to diverse disease pathologies and how inherited mutations that compromise lysosomal hydrolysis, transport or signalling components lead to multi-organ disorders with severe metabolic and neurological impact. A deeper comprehension of lysosomal composition and function, at both the cellular and organismal level, may uncover fundamental insights into human physiology and disease.
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Affiliation(s)
- Carmine Settembre
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli, Italy.
- Department of Clinical Medicine and Surgery, Federico II University, Naples, Italy.
| | - Rushika M Perera
- Department of Anatomy, University of California at San Francisco, San Francisco, CA, USA.
- Department of Pathology, University of California at San Francisco, San Francisco, CA, USA.
- Helen Diller Family Comprehensive Cancer Center, University of California at San Francisco, San Francisco, CA, USA.
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12
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Mulligan R, Magaj M, Digilio L, Redemann S, Yap C, Winckler B. Collapse of late endosomal pH elicits a rapid Rab7 response via V-ATPase and RILP. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.10.24.563658. [PMID: 37961579 PMCID: PMC10634777 DOI: 10.1101/2023.10.24.563658] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Endosomal-lysosomal trafficking is accompanied by the acidification of endosomal compartments by the H+-V-ATPase to reach low lysosomal pH. Disruption of proper pH impairs lysosomal function and the balance of protein synthesis and degradation (proteostasis). We used the small dipeptide LLOMe, which is known to permeabilize lysosomal membranes, and find that LLOMe also impacts late endosomes (LEs) by neutralizing their pH without causing membrane permeabilization. We show that LLOMe leads to hyper-activation of Rab7 and disruption of tubulation and mannose-6-phosphate receptor (CI-M6PR) recycling on pH-neutralized LEs. Either pH neutralization (NH4Cl) or Rab7 hyper-active mutants alone can phenocopy the alterations in tubulation and CI-M6PR trafficking. Mechanistically, pH neutralization increases the assembly of the V1G1 subunit of the V-ATPase on endosomal membranes, which stabilizes GTP-bound Rab7 via RILP, a known interactor of Rab7 and V1G1. We propose a novel pathway by which V-ATPase and RILP modulate LE pH and Rab7 activation in concert. This pathway might broadly contribute to pH control during physiologic endosomal maturation or starvation and during pathologic pH neutralization, which occurs via lysosomotropic compounds or in disease states.
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Affiliation(s)
- R.J. Mulligan
- Department of Cell Biology, University of Virginia, Charlottesville, VA
- Cell and Developmental Biology Graduate Program, University of Virginia, Charlottesville, VA
- Medical Scientist Training Program, University of Virginia, Charlottesville, VA
| | - M.M. Magaj
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville VA
- Cell and Developmental Biology Graduate Program, University of Virginia, Charlottesville, VA
| | - L. Digilio
- Department of Cell Biology, University of Virginia, Charlottesville, VA
| | - S. Redemann
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville VA
- Center for Membrane and Cell Physiology, University of Virginia, Charlottesville, VA
| | - C.C. Yap
- Department of Cell Biology, University of Virginia, Charlottesville, VA
| | - B Winckler
- Department of Cell Biology, University of Virginia, Charlottesville, VA
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13
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Yu Y, Gao SM, Guan Y, Hu PW, Zhang Q, Liu J, Jing B, Zhao Q, Sabatini DM, Abu-Remaileh M, Jung SY, Wang MC. Organelle proteomic profiling reveals lysosomal heterogeneity in association with longevity. eLife 2024; 13:e85214. [PMID: 38240316 PMCID: PMC10876212 DOI: 10.7554/elife.85214] [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: 11/28/2022] [Accepted: 01/18/2024] [Indexed: 02/20/2024] Open
Abstract
Lysosomes are active sites to integrate cellular metabolism and signal transduction. A collection of proteins associated with the lysosome mediate these metabolic and signaling functions. Both lysosomal metabolism and lysosomal signaling have been linked to longevity regulation; however, how lysosomes adjust their protein composition to accommodate this regulation remains unclear. Using deep proteomic profiling, we systemically profiled lysosome-associated proteins linked with four different longevity mechanisms. We discovered the lysosomal recruitment of AMP-activated protein kinase and nucleoporin proteins and their requirements for longevity in response to increased lysosomal lipolysis. Through comparative proteomic analyses of lysosomes from different tissues and labeled with different markers, we further elucidated lysosomal heterogeneity across tissues as well as the increased enrichment of the Ragulator complex on Cystinosin-positive lysosomes. Together, this work uncovers lysosomal proteome heterogeneity across multiple scales and provides resources for understanding the contribution of lysosomal protein dynamics to signal transduction, organelle crosstalk, and organism longevity.
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Affiliation(s)
- Yong Yu
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Faculty of Medicine and Life Sciences, Xiamen UniversityXiamenChina
- Huffington Center on Aging, Baylor College of MedicineHoustonUnited States
| | - Shihong M Gao
- Developmental Biology Graduate Program, Baylor College of MedicineHoustonUnited States
- Janelia Research Campus, Howard Hughes Medical InstituteAshburnUnited States
| | - Youchen Guan
- Janelia Research Campus, Howard Hughes Medical InstituteAshburnUnited States
- Molecular and Cellular Biology Graduate Program, Baylor College of MedicineHoustonUnited States
| | - Pei-Wen Hu
- Huffington Center on Aging, Baylor College of MedicineHoustonUnited States
| | - Qinghao Zhang
- Huffington Center on Aging, Baylor College of MedicineHoustonUnited States
| | - Jiaming Liu
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Faculty of Medicine and Life Sciences, Xiamen UniversityXiamenChina
| | - Bentian Jing
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Faculty of Medicine and Life Sciences, Xiamen UniversityXiamenChina
| | - Qian Zhao
- Janelia Research Campus, Howard Hughes Medical InstituteAshburnUnited States
| | - David M Sabatini
- Institute of Organic Chemistry and BiochemistryPragueCzech Republic
| | - Monther Abu-Remaileh
- Institute for Chemistry, Engineering and Medicine for Human Health (ChEM-H), Stanford UniversityStanfordUnited States
- Department of Chemical Engineering and Genetics, Stanford UniversityStanfordUnited States
| | - Sung Yun Jung
- Department of Molecular and Cellular Biology, Baylor College of MedicineHoustonUnited States
| | - Meng C Wang
- Huffington Center on Aging, Baylor College of MedicineHoustonUnited States
- Janelia Research Campus, Howard Hughes Medical InstituteAshburnUnited States
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14
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Choi JT, Choi Y, Lee Y, Lee SH, Kang S, Lee KT, Bahn YS. The hybrid RAVE complex plays V-ATPase-dependent and -independent pathobiological roles in Cryptococcus neoformans. PLoS Pathog 2023; 19:e1011721. [PMID: 37812645 PMCID: PMC10586682 DOI: 10.1371/journal.ppat.1011721] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Revised: 10/19/2023] [Accepted: 09/29/2023] [Indexed: 10/11/2023] Open
Abstract
V-ATPase, which comprises 13-14 subunits, is essential for pH homeostasis in all eukaryotes, but its proper function requires a regulator to assemble its subunits. While RAVE (regulator of H+-ATPase of vacuolar and endosomal membranes) and Raboconnectin-3 complexes assemble V-ATPase subunits in Saccharomyces cerevisiae and humans, respectively, the function of the RAVE complex in fungal pathogens remains largely unknown. In this study, we identified two RAVE complex components, Rav1 and Wdr1, in the fungal meningitis pathogen Cryptococcus neoformans, and analyzed their roles. Rav1 and Wdr1 are orthologous to yeast RAVE and human Rabconnectin-3 counterparts, respectively, forming the hybrid RAVE (hRAVE) complex. Deletion of RAV1 caused severe defects in growth, cell cycle control, morphogenesis, sexual development, stress responses, and virulence factor production, while the deletion of WDR1 resulted in similar but modest changes, suggesting that Rav1 and Wdr1 play central and accessary roles, respectively. Proteomics analysis confirmed that Wdr1 was one of the Rav1-interacting proteins. Although the hRAVE complex generally has V-ATPase-dependent functions, it also has some V-ATPase-independent roles, suggesting a unique role beyond conventional intracellular pH regulation in C. neoformans. The hRAVE complex played a critical role in the pathogenicity of C. neoformans, and RAV1 deletion attenuated virulence and impaired blood-brain barrier crossing ability. This study provides comprehensive insights into the pathobiological roles of the fungal RAVE complex and suggests a novel therapeutic strategy for controlling cryptococcosis.
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Affiliation(s)
- Jin-Tae Choi
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, Korea
| | - Yeseul Choi
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, Korea
| | - Yujin Lee
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, Korea
| | - Seung-Heon Lee
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, Korea
| | - Seun Kang
- Korea Zoonosis Research Institute, Jeonbuk National University, Jeonbuk, Republic of Korea
| | - Kyung-Tae Lee
- Korea Zoonosis Research Institute, Jeonbuk National University, Jeonbuk, Republic of Korea
| | - Yong-Sun Bahn
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, Korea
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15
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Taya T, Teruyama F, Gojo S. Host-directed therapy for bacterial infections -Modulation of the phagolysosome pathway. Front Immunol 2023; 14:1227467. [PMID: 37841276 PMCID: PMC10570837 DOI: 10.3389/fimmu.2023.1227467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Accepted: 09/11/2023] [Indexed: 10/17/2023] Open
Abstract
Bacterial infections still impose a significant burden on humanity, even though antimicrobial agents have long since been developed. In addition to individual severe infections, the f fatality rate of sepsis remains high, and the threat of antimicrobial-resistant bacteria grows with time, putting us at inferiority. Although tremendous resources have been devoted to the development of antimicrobial agents, we have yet to recover from the lost ground we have been driven into. Looking back at the evolution of treatment for cancer, which, like infectious diseases, has the similarity that host immunity eliminates the lesion, the development of drugs to eliminate the tumor itself has shifted from a single-minded focus on drug development to the establishment of a treatment strategy in which the de-suppression of host immunity is another pillar of treatment. In infectious diseases, on the other hand, the development of therapies that strengthen and support the immune system has only just begun. Among innate immunity, the first line of defense that bacteria encounter after invading the host, the molecular mechanisms of the phagolysosome pathway, which begins with phagocytosis to fusion with lysosome, have been elucidated in detail. Bacteria have a large number of strategies to escape and survive the pathway. Although the full picture is still unfathomable, the molecular mechanisms have been elucidated for some of them, providing sufficient clues for intervention. In this article, we review the host defense mechanisms and bacterial evasion mechanisms and discuss the possibility of host-directed therapy for bacterial infection by intervening in the phagolysosome pathway.
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Affiliation(s)
- Toshihiko Taya
- Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Fumiya Teruyama
- Pharmacology Research Department, Tokyo New Drug Research Laboratories, Kowa Company, Ltd., Tokyo, Japan
- Department of Regenerative Medicine, Graduate School of Medicine, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Satoshi Gojo
- Department of Regenerative Medicine, Graduate School of Medicine, Kyoto Prefectural University of Medicine, Kyoto, Japan
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16
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Xu M, Zhong XZ, Huang P, Jaślan D, Wang P, Sun X, Weiden EM, EL Hiani Y, Grimm C, Dong XP. TRPML3/BK complex promotes autophagy and bacterial clearance by providing a positive feedback regulation of mTOR via PI3P. Proc Natl Acad Sci U S A 2023; 120:e2215777120. [PMID: 37585464 PMCID: PMC10450854 DOI: 10.1073/pnas.2215777120] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Accepted: 06/22/2023] [Indexed: 08/18/2023] Open
Abstract
TRPML3 is a Ca2+/Na+ release channel residing in both phagophores and endolysosomal membranes. It is activated by PI3P and PI3,5P2. Its activity can be enhanced by high luminal pH and by replacing luminal Na+ with K+. Here, we report that big-conductance Ca2+-activated potassium (BK) channels form a positive feedback loop with TRPML3. Ca2+ release via TRPML3 activates BK, which in turn facilitates TRPML3-mediated Ca2+ release, potentially through removing luminal Na+ inhibition. We further show that TRPML3/BK and mammalian target of rapamycin (mTOR) form another positive feedback loop to facilitate autophagy induction in response to nutrient starvation, i.e., mTOR inhibition upon nutrient starvation activates TRPML3/BK, and this further reduces mTOR activity, thereby increasing autophagy induction. Mechanistically, the feedback regulation between TRPML3/BK and mTOR is mediated by PI3P, an endogenous TRPML3 activator that is enriched in phagophores and is up-regulated by mTOR reduction. Importantly, bacterial infection activates TRPML3 in a BK-dependent manner, and both TRPML3 and BK are required for mTOR suppression and autophagy induction responding to bacterial infection. Suppressing either TRPML3 or BK helps bacteria survival whereas increasing either TRPML3 or BK favors bacterial clearance. Considering that TRPML3/BK is inhibited by low luminal pH but activated by high luminal pH and PI3P in phagophores, we suggest that TRPML3/BK and mTOR form a positive feedback loop via PI3P to ensure efficient autophagy induction in response to nutrient deprivation and bacterial infection. Our study reveals a role of TRPML3-BK coupling in controlling cellular homeostasis and intracellular bacterial clearance via regulating mTOR signaling.
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Affiliation(s)
- Mengnan Xu
- Department of Physiology and Biophysics, Dalhousie University, Halifax, NSB3H 4R2, Canada
| | - Xi Zoë Zhong
- Department of Physiology and Biophysics, Dalhousie University, Halifax, NSB3H 4R2, Canada
| | - Peng Huang
- Department of Physiology and Biophysics, Dalhousie University, Halifax, NSB3H 4R2, Canada
- Chongming Hospital, Shanghai University of Medicine and Health Sciences, Shanghai202150, China
| | - Dawid Jaślan
- Walther Straub Institute of Pharmacology and Toxicology, Faculty of Medicine, Ludwig-Maximilians-Universität, Munich80336, Germany
| | - Pingping Wang
- Department of Physiology and Biophysics, Dalhousie University, Halifax, NSB3H 4R2, Canada
| | - Xue Sun
- Department of Physiology and Biophysics, Dalhousie University, Halifax, NSB3H 4R2, Canada
- Department of Developmental Cell Biology, China Medical University, Shenbei New District, Shenyang110122, China
| | - Eva-Maria Weiden
- Walther Straub Institute of Pharmacology and Toxicology, Faculty of Medicine, Ludwig-Maximilians-Universität, Munich80336, Germany
| | - Yassine EL Hiani
- Department of Physiology and Biophysics, Dalhousie University, Halifax, NSB3H 4R2, Canada
| | - Christian Grimm
- Walther Straub Institute of Pharmacology and Toxicology, Faculty of Medicine, Ludwig-Maximilians-Universität, Munich80336, Germany
- Immunology, Infection and Pandemic Research, Fraunhofer Institute for Translational Medicine and Pharmacology, Munich80799, Germany
| | - Xian-Ping Dong
- Department of Physiology and Biophysics, Dalhousie University, Halifax, NSB3H 4R2, Canada
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17
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Li B, Khan MZ, Khan IM, Ullah Q, Cisang ZM, Zhang N, Wu D, Huang B, Ma Y, Khan A, Jiang N, Zahoor M. Genetics, environmental stress, and amino acid supplementation affect lactational performance via mTOR signaling pathway in bovine mammary epithelial cells. Front Genet 2023; 14:1195774. [PMID: 37636261 PMCID: PMC10448190 DOI: 10.3389/fgene.2023.1195774] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Accepted: 06/26/2023] [Indexed: 08/29/2023] Open
Abstract
Mammary glands are known for their ability to convert nutrients present in the blood into milk contents. In cows, milk synthesis and the proliferation of cow mammary epithelial cells (CMECs) are regulated by various factors, including nutrients such as amino acids and glucose, hormones, and environmental stress. Amino acids, in particular, play a crucial role in regulating cell proliferation and casein synthesis in mammalian epithelial cells, apart from being building blocks for protein synthesis. Studies have shown that environmental factors, particularly heat stress, can negatively impact milk production performance in dairy cattle. The mammalian target of rapamycin complex 1 (mTORC1) pathway is considered the primary signaling pathway involved in regulating cell proliferation and milk protein and fat synthesis in cow mammary epithelial cells in response to amino acids and heat stress. Given the significant role played by the mTORC signaling pathway in milk synthesis and cell proliferation, this article briefly discusses the main regulatory genes, the impact of amino acids and heat stress on milk production performance, and the regulation of mTORC signaling pathway in cow mammary epithelial cells.
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Affiliation(s)
- Bin Li
- Institute of Animal Husbandry and Veterinary, Tibet Autonomous Regional Academy of Agricultural Sciences, Lhasa, China
| | - Muhammad Zahoor Khan
- Liaocheng Research Institute of Donkey High‐Efficiency Breeding and Ecological Feeding, Agricultural Science and Engineering School, Liaocheng University, Liaocheng, China
- Faculty of Veterinary and Animal Sciences, The University of Agriculture, Dera Ismail Khan, Pakistan
| | - Ibrar Muhammad Khan
- Anhui Province Key Laboratory of Embryo Development and Reproduction Regulation, Anhui Province Key Laboratory of Environmental Hormone and Reproduction, School of Biological and Food Engineering, Fuyang Normal University, Fuyang, China
| | - Qudrat Ullah
- Faculty of Veterinary and Animal Sciences, The University of Agriculture, Dera Ismail Khan, Pakistan
| | - Zhuo-Ma Cisang
- Institute of Animal Husbandry and Veterinary, Tibet Autonomous Regional Academy of Agricultural Sciences, Lhasa, China
| | - Nan Zhang
- Tibet Autonomous Region Animal Husbandry Station, Lhasa, China
| | - Dan Wu
- Institute of Animal Husbandry and Veterinary, Tibet Autonomous Regional Academy of Agricultural Sciences, Lhasa, China
| | - Bingjian Huang
- Liaocheng Research Institute of Donkey High‐Efficiency Breeding and Ecological Feeding, Agricultural Science and Engineering School, Liaocheng University, Liaocheng, China
- College of Life Sciences, Liaocheng University, Liaocheng, China
| | - Yulin Ma
- State Key Laboratory of Animal Nutrition, Beijing Engineering Technology Research Center of Raw Milk Quality and Safety Control, College of Animal Science and Technology, China Agricultural University, Beijing, China
| | - Adnan Khan
- Genome Analysis Laboratory of the Ministry of Agriculture, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, China
| | - Nan Jiang
- Institute of Animal Husbandry and Veterinary, Tibet Autonomous Regional Academy of Agricultural Sciences, Lhasa, China
| | - Muhammad Zahoor
- Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
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18
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Im E, Jiang Y, Stavrides PH, Darji S, Erdjument-Bromage H, Neubert TA, Choi JY, Wegiel J, Lee JH, Nixon RA. Lysosomal dysfunction in Down syndrome and Alzheimer mouse models is caused by v-ATPase inhibition by Tyr 682-phosphorylated APP βCTF. SCIENCE ADVANCES 2023; 9:eadg1925. [PMID: 37494443 PMCID: PMC10371027 DOI: 10.1126/sciadv.adg1925] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Accepted: 06/23/2023] [Indexed: 07/28/2023]
Abstract
Lysosome dysfunction arises early and propels Alzheimer's disease (AD). Herein, we show that amyloid precursor protein (APP), linked to early-onset AD in Down syndrome (DS), acts directly via its β-C-terminal fragment (βCTF) to disrupt lysosomal vacuolar (H+)-adenosine triphosphatase (v-ATPase) and acidification. In human DS fibroblasts, the phosphorylated 682YENPTY internalization motif of APP-βCTF binds selectively within a pocket of the v-ATPase V0a1 subunit cytoplasmic domain and competitively inhibits association of the V1 subcomplex of v-ATPase, thereby reducing its activity. Lowering APP-βCTF Tyr682 phosphorylation restores v-ATPase and lysosome function in DS fibroblasts and in vivo in brains of DS model mice. Notably, lowering APP-βCTF Tyr682 phosphorylation below normal constitutive levels boosts v-ATPase assembly and activity, suggesting that v-ATPase may also be modulated tonically by phospho-APP-βCTF. Elevated APP-βCTF Tyr682 phosphorylation in two mouse AD models similarly disrupts v-ATPase function. These findings offer previously unknown insight into the pathogenic mechanism underlying faulty lysosomes in all forms of AD.
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Affiliation(s)
- Eunju Im
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY 10962, USA
- Department of Psychiatry, New York University Grossman School of Medicine, New York, NY 10016, USA
| | - Ying Jiang
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY 10962, USA
- Department of Psychiatry, New York University Grossman School of Medicine, New York, NY 10016, USA
| | - Philip H. Stavrides
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY 10962, USA
| | - Sandipkumar Darji
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY 10962, USA
| | - Hediye Erdjument-Bromage
- Department of Cell Biology, New York University Grossman School of Medicine, New York, NY 10016, USA
- Kimmel Center for Biology and Medicine at the Skirball Institute, New York University Grossman School of Medicine, New York, NY, 10016, USA
| | - Thomas A. Neubert
- Department of Cell Biology, New York University Grossman School of Medicine, New York, NY 10016, USA
- Kimmel Center for Biology and Medicine at the Skirball Institute, New York University Grossman School of Medicine, New York, NY, 10016, USA
| | - Jun Yong Choi
- Department of Chemistry and Biochemistry, Queens College, Queens, NY 11367, USA
- Ph.D. Programs in Chemistry and Biochemistry, The Graduate Center of the City University of New York, New York, NY 10016, USA
| | - Jerzy Wegiel
- Department of Developmental Neurobiology, New York State Institute for Basic Research in Developmental Disabilities, Staten Island, NY 10314, USA
| | - Ju-Hyun Lee
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY 10962, USA
- Department of Psychiatry, New York University Grossman School of Medicine, New York, NY 10016, USA
| | - Ralph A. Nixon
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY 10962, USA
- Department of Psychiatry, New York University Grossman School of Medicine, New York, NY 10016, USA
- Department of Cell Biology, New York University Grossman School of Medicine, New York, NY 10016, USA
- NYU Neuroscience Institute, New York University Grossman School of Medicine, New York, NY 10016, USA
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19
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Sharma A, Narasimha K, Manjithaya R, Sheeba V. Restoration of Sleep and Circadian Behavior by Autophagy Modulation in Huntington's Disease. J Neurosci 2023; 43:4907-4925. [PMID: 37268416 PMCID: PMC10312063 DOI: 10.1523/jneurosci.1894-22.2023] [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: 10/07/2022] [Revised: 01/25/2023] [Accepted: 02/16/2023] [Indexed: 06/04/2023] Open
Abstract
Circadian and sleep defects are well documented in Huntington's disease (HD). Modulation of the autophagy pathway has been shown to mitigate toxic effects of mutant Huntingtin (HTT) protein. However, it is not clear whether autophagy induction can also rescue circadian and sleep defects. Using a genetic approach, we expressed human mutant HTT protein in a subset of Drosophila circadian neurons and sleep center neurons. In this context, we examined the contribution of autophagy in mitigating toxicity caused by mutant HTT protein. We found that targeted overexpression of an autophagy gene, Atg8a in male flies, induces autophagy pathway and partially rescues several HTT-induced behavioral defects, including sleep fragmentation, a key hallmark of many neurodegenerative disorders. Using cellular markers and genetic approaches, we demonstrate that indeed the autophagy pathway is involved in behavioral rescue. Surprisingly, despite behavioral rescue and evidence for the involvement of the autophagy pathway, the large visible aggregates of mutant HTT protein were not eliminated. We show that the rescue in behavior is associated with increased mutant protein aggregation and possibly enhanced output from the targeted neurons, resulting in the strengthening of downstream circuits. Overall, our study suggests that, in the presence of mutant HTT protein, Atg8a induces autophagy and improves the functioning of circadian and sleep circuits.SIGNIFICANCE STATEMENT Defects in sleep and circadian rhythms are well documented in Huntington's disease. Recent literature suggests that circadian and sleep disturbances can exacerbate neurodegenerative phenotypes. Hence, identifying potential modifiers that can improve the functioning of these circuits could greatly improve disease management. We used a genetic approach to enhance cellular proteostasis and found that overexpression of a crucial autophagy gene, Atg8a, induces the autophagy pathway in the Drosophila circadian and sleep neurons and rescues sleep and activity rhythm. We demonstrate that the Atg8a improves synaptic function of these circuits by possibly enhancing the aggregation of the mutant protein in neurons. Further, our results suggest that differences in basal levels of protein homeostatic pathways is a factor that determines selective susceptibility of neurons.
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Affiliation(s)
- Ankit Sharma
- Chronobiology and Behavioural Neurogenetics Laboratory, Neuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, 560064, India
| | - Kavyashree Narasimha
- Chronobiology and Behavioural Neurogenetics Laboratory, Neuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, 560064, India
| | - Ravi Manjithaya
- Autophagy Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, 560064, India
| | - Vasu Sheeba
- Chronobiology and Behavioural Neurogenetics Laboratory, Neuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, 560064, India
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20
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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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21
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Wang H, Rubinstein JL. CryoEM of V-ATPases: Assembly, disassembly, and inhibition. Curr Opin Struct Biol 2023; 80:102592. [PMID: 37272327 DOI: 10.1016/j.sbi.2023.102592] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 03/13/2023] [Accepted: 03/16/2023] [Indexed: 06/06/2023]
Abstract
Vacuolar-type ATPases (V-ATPases) are responsible for the acidification of intracellular compartments in almost all eukaryotic cells, while in some specialized cells they acidify the extracellular environment. As ubiquitous proton pumps, these large membrane-embedded enzymes are involved in many fundamental cellular processes that require tight control of pH. Consequently, V-ATPase malfunction or aberrant activity has been linked to numerous diseases. In the past ten years, electron cryomicroscopy (cryoEM) of yeast V-ATPases has revealed the architecture and rotary catalytic mechanism of these macromolecular machines. More recently, studies have revealed the structures of V-ATPases in animals and plants, uncovered aspects of how V-ATPases are assembled and regulated by reversible dissociation, and shown how V-ATPase activity can be modulated by proteins and small molecule inhibitors. In this review, we highlight these recent developments.
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Affiliation(s)
- Hanlin Wang
- Molecular Medicine Program, The Hospital for Sick Children, M5G 0A4, Toronto, Canada; Department of Biochemistry, The University of Toronto, M5G 1L7, Toronto, Canada
| | - John L Rubinstein
- Molecular Medicine Program, The Hospital for Sick Children, M5G 0A4, Toronto, Canada; Department of Biochemistry, The University of Toronto, M5G 1L7, Toronto, Canada; Department of Medical Biophysics, The University of Toronto, M5S 1A8, Toronto, Canada.
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22
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Suzuki Y, Kami D, Taya T, Sano A, Ogata T, Matoba S, Gojo S. ZLN005 improves the survival of polymicrobial sepsis by increasing the bacterial killing via inducing lysosomal acidification and biogenesis in phagocytes. Front Immunol 2023; 14:1089905. [PMID: 36820088 PMCID: PMC9938763 DOI: 10.3389/fimmu.2023.1089905] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Accepted: 01/23/2023] [Indexed: 02/07/2023] Open
Abstract
Polymicrobial sepsis still has a high mortality rate despite the development of antimicrobial agents, elaborate strategies to protect major organs, and the investment of numerous medical resources. Mitochondrial dysfunction, which acts as the center of energy metabolism, is clearly the basis of pathogenesis. Drugs that act on PGC1α, the master regulator of mitochondrial biosynthesis, have shown useful effects in the treatment of sepsis; therefore, we investigated the efficacy of ZLN005, a PGC1α agonist, and found significant improvement in overall survival in an animal model. The mode of action of this effect was examined, and it was shown that the respiratory capacity of mitochondria was enhanced immediately after administration and that the function of TFEB, a transcriptional regulator that promotes lysosome biosynthesis and mutually enhances PGC1α, was enhanced, as was the physical contact between mitochondria and lysosomes. ZLN005 strongly supported immune defense in early sepsis by increasing lysosome volume and acidity and enhancing cargo degradation, resulting in a significant reduction in bacterial load. ZLN005 rapidly acted on two organelles, mitochondria and lysosomes, against sepsis and interactively linked the two to improve the pathogenesis. This is the first demonstration that acidification of lysosomes by a small molecule is a mechanism of action in the therapeutic strategy for sepsis, which will have a significant impact on future drug discovery.
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Affiliation(s)
- Yosuke Suzuki
- Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Daisuke Kami
- Department of Regenerative Medicine, Graduate School of Medicine, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Toshihiko Taya
- Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Arata Sano
- Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Takehiro Ogata
- Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto Prefectural University of Medicine, Kyoto, Japan
- Department of Pathology and Cell Regulation, Graduate School of Medicine, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Satoaki Matoba
- Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Satoshi Gojo
- Department of Regenerative Medicine, Graduate School of Medicine, Kyoto Prefectural University of Medicine, Kyoto, Japan
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23
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Patra S, Patil S, Klionsky DJ, Bhutia SK. Lysosome signaling in cell survival and programmed cell death for cellular homeostasis. J Cell Physiol 2023; 238:287-305. [PMID: 36502521 DOI: 10.1002/jcp.30928] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 11/06/2022] [Accepted: 11/24/2022] [Indexed: 12/14/2022]
Abstract
Recent developments in lysosome biology have transformed our view of lysosomes from static garbage disposals that can also act as suicide bags to decidedly dynamic multirole adaptive operators of cellular homeostasis. Lysosome-governed signaling pathways, proteins, and transcription factors equilibrate the rate of catabolism and anabolism (autophagy to lysosomal biogenesis and metabolite pool maintenance) by sensing cellular metabolic status. Lysosomes also interact with other organelles by establishing contact sites through which they exchange cellular contents. Lysosomal function is critically assessed by lysosomal positioning and motility for cellular adaptation. In this setting, mechanistic target of rapamycin kinase (MTOR) is the chief architect of lysosomal signaling to control cellular homeostasis. Notably, lysosomes can orchestrate explicit cell death mechanisms, such as autophagic cell death and lysosomal membrane permeabilization-associated regulated necrotic cell death, to maintain cellular homeostasis. These lines of evidence emphasize that the lysosomes serve as a central signaling hub for cellular homeostasis.
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Affiliation(s)
- Srimanta Patra
- Cancer and Cell Death Laboratory, Department of Life Science, National Institute of Technology, Rourkela, Odisha, India
| | - Shankargouda Patil
- Division of Oral Pathology, Department of Maxillofacial Surgery and Diagnostic Sciences, College of Dentistry, Jazan University, Jazan, Saudi Arabia
| | - Daniel J Klionsky
- Department of Molecular, Cellular and Developmental Biology, Life Sciences Institute, University of Michigan, Ann Arbor, Michigan, USA
| | - Sujit K Bhutia
- Cancer and Cell Death Laboratory, Department of Life Science, National Institute of Technology, Rourkela, Odisha, India
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24
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Tolani B, Celli A, Yao Y, Tan YZ, Fetter R, Liem CR, de Smith AJ, Vasanthakumar T, Bisignano P, Cotton AD, Seiple IB, Rubinstein JL, Jost M, Weissman JS. Ras-mutant cancers are sensitive to small molecule inhibition of V-type ATPases in mice. Nat Biotechnol 2022; 40:1834-1844. [PMID: 35879364 PMCID: PMC9750872 DOI: 10.1038/s41587-022-01386-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 06/03/2022] [Indexed: 01/14/2023]
Abstract
Mutations in Ras family proteins are implicated in 33% of human cancers, but direct pharmacological inhibition of Ras mutants remains challenging. As an alternative to direct inhibition, we screened for sensitivities in Ras-mutant cells and discovered 249C as a Ras-mutant selective cytotoxic agent with nanomolar potency against a spectrum of Ras-mutant cancers. 249C binds to vacuolar (V)-ATPase with nanomolar affinity and inhibits its activity, preventing lysosomal acidification and inhibiting autophagy and macropinocytosis pathways that several Ras-driven cancers rely on for survival. Unexpectedly, potency of 249C varies with the identity of the Ras driver mutation, with the highest potency for KRASG13D and G12V both in vitro and in vivo, highlighting a mutant-specific dependence on macropinocytosis and lysosomal pH. Indeed, 249C potently inhibits tumor growth without adverse side effects in mouse xenografts of KRAS-driven lung and colon cancers. A comparison of isogenic SW48 xenografts with different KRAS mutations confirmed that KRASG13D/+ (followed by G12V/+) mutations are especially sensitive to 249C treatment. These data establish proof-of-concept for targeting V-ATPase in cancers driven by specific KRAS mutations such as KRASG13D and G12V.
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Affiliation(s)
- Bhairavi Tolani
- Thoracic Oncology Program, Department of Surgery, Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, CA, USA.
| | - Anna Celli
- Laboratory for Cell Analysis Core Facility, Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, CA, USA
| | - Yanmin Yao
- Department of Pharmaceutical Chemistry and Cardiovascular Research Institute, University of California, San Francisco, CA, USA
| | - Yong Zi Tan
- Molecular Medicine Program, The Hospital for Sick Children, Toronto, ON, Canada
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
- Disease Intervention Technology Laboratory, Agency for Science, Technology and Research, Singapore, Singapore
| | - Richard Fetter
- Howard Hughes Medical Institute, Department of Biology, Stanford University, Stanford, CA, USA
| | - Christina R Liem
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA, USA
- Division of Biological Sciences, the Section of Cell and Developmental Biology, University of California San Diego, La Jolla, CA, USA
| | - Adam J de Smith
- Center for Genetic Epidemiology, Department of Population and Public Health Sciences, Keck School of Medicine of University of Southern California, Los Angeles, CA, USA
| | - Thamiya Vasanthakumar
- Molecular Medicine Program, The Hospital for Sick Children, Toronto, ON, Canada
- Department of Biochemistry, The University of Toronto, Toronto, ON, Canada
| | - Paola Bisignano
- Department of Pharmaceutical Chemistry and Cardiovascular Research Institute, University of California, San Francisco, CA, USA
| | - Adam D Cotton
- Department of Pharmaceutical Chemistry and Cardiovascular Research Institute, University of California, San Francisco, CA, USA
| | - Ian B Seiple
- Department of Pharmaceutical Chemistry and Cardiovascular Research Institute, University of California, San Francisco, CA, USA
| | - John L Rubinstein
- Molecular Medicine Program, The Hospital for Sick Children, Toronto, ON, Canada
- Department of Biochemistry, The University of Toronto, Toronto, ON, Canada
- Department of Medical Biophysics, The University of Toronto, Toronto, ON, Canada
| | - Marco Jost
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA, USA.
- Department of Microbiology & Immunology, University of California, San Francisco, CA, USA.
- Department of Microbiology, Harvard Medical School, Boston, MA, USA.
| | - Jonathan S Weissman
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA, USA
- Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA, USA
- Whitehead Institute for Biomedical Research, Massachusetts Institute of Technology, Cambridge, MA, USA
- David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, USA
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
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25
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Kim KR, Park SE, Hong JY, Koh JY, Cho DH, Hwang JJ, Kim YH. Zinc enhances autophagic flux and lysosomal function through transcription factor EB activation and V-ATPase assembly. Front Cell Neurosci 2022; 16:895750. [PMID: 36246521 PMCID: PMC9558701 DOI: 10.3389/fncel.2022.895750] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 08/22/2022] [Indexed: 11/13/2022] Open
Abstract
The stimulation of autophagy or lysosomes has been considered therapeutic for neurodegenerative disorders because the accumulation of misfolded proteins is commonly observed in the brains of individuals with these diseases. Although zinc is known to play critical roles in the functions of lysosomes and autophagy, the mechanism behind this regulatory relationship remains unclear. Therefore, in this study, we examined which mechanism is involved in zinc-mediated activation of autophagy and lysosome. Exposure to zinc at a sub-lethal concentration activated autophagy in a concentration-dependent manner in mRFP-GFP-LC3-expressing H4 glioma cells. Zinc also rescued the blocking of autophagic flux arrested by pharmaceutical de-acidification. Co-treatment with zinc attenuated the chloroquine (CQ)-induced increase in the number and size of mRFP-GFP-LC3 puncta in H4 cells and accumulation of p62 by CQ or ammonium chloride in both H4 and mouse cerebrocortical cultures. Zinc rapidly induced the expression of cathepsin B (CTSB) and cathepsin D (CTSD), representative lysosomal proteases in neurons, which appeared likely to be mediated by transcription factor EB (TFEB). We observed the translocation of TFEB from neurite to nucleus and the dephosphorylation of TFEB by zinc. The addition of cycloheximide, a chemical inhibitor of protein synthesis, inhibited the activity of CTSB and CTSD at 8 h after zinc exposure but not at 1 h, indicating that only late lysosomal activation was dependent on the synthesis of CTSB and CTSD proteins. At the very early time point, the activation of cathepsins was mediated by an increased assembly of V-ATPase on lysosomes and resultant lysosomal acidification. Finally, considering that P301L mutation in tau protein causes frontotemporal dementia through aggressive tau accumulation, we investigated whether zinc reduces the accumulation of protein aggregates in SK-N-BE(2)-C neuroblastoma cells expressing wild-type tau or mutant P301L-tau. Zinc markedly attenuated the levels of phosphorylated tau and total tau as well as p62 in both wild-type and mutant tau-overexpressing cells. We also observed that zinc was more effective than rapamycin at inducing TFEB-dependent CTSB and CTSD expression and V-ATPase-dependent lysosomal acidification and CTSB/CTSD activation. These results suggest that the regulation of zinc homeostasis could be a new approach for developing treatments for neurodegenerative diseases, including Alzheimer’s and Parkinson’s.
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Affiliation(s)
- Ki-Ryeong Kim
- Department of Integrative Bioscience and Biotechnology, Sejong University, Seoul, South Korea
| | - Sang Eun Park
- Asan Institute for Life Sciences, Asan Medical Center, Seoul, South Korea
| | - Ji-Ye Hong
- Asan Institute for Life Sciences, Asan Medical Center, Seoul, South Korea
| | - Jae-Young Koh
- Department of Neurology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea
- Neuronal Injury Lab, Biomedical Research Center, Asan Institute for Life Sciences, Asan Medical Center, Seoul, South Korea
| | - Dong-Hyung Cho
- BK21 FOUR KNU Creative BioResearch Group, School of Life Sciences, Kyungpook National University, Daegu, South Korea
| | - Jung Jin Hwang
- Asan Institute for Life Sciences, Asan Medical Center, Seoul, South Korea
- Jung Jin Hwang,
| | - Yang-Hee Kim
- Department of Integrative Bioscience and Biotechnology, Sejong University, Seoul, South Korea
- *Correspondence: Yang-Hee Kim,
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26
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Jeon H, Kim YJ, Hwang SK, Seo J, Mun JY. Restoration of Cathepsin D Level via L-Serine Attenuates PPA-Induced Lysosomal Dysfunction in Neuronal Cells. Int J Mol Sci 2022; 23:ijms231810613. [PMID: 36142514 PMCID: PMC9504002 DOI: 10.3390/ijms231810613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 09/05/2022] [Accepted: 09/08/2022] [Indexed: 11/21/2022] Open
Abstract
L-serine is a non-essential amino acid endogenously produced by astrocytes and is abundant in human diets. Beneficial roles of the metabolic products from L-serine in various conditions in the brain including neuronal development have been reported. Through several preclinical studies, L-serine treatment was also shown to offer beneficial therapeutic effects for brain damage such as ischemic stroke, amyotrophic lateral sclerosis, and Parkinson’s disease. Despite evidence for the value of L-serine in the clinic, however, its beneficial effects on the propionic acid (PPA)-induced neuronal toxicity and underlying mechanisms of L-serine-mediated neuroprotection are unknown. In this study, we observed that PPA-induced acidic stress induces abnormal lipid accumulation and functional defects in lysosomes of hippocampal neurons. L-serine treatment was able to rescue the structure and function of lysosomes in PPA-treated hippocampal neuronal cells. We further identified that L-serine suppressed the formation of lipid droplets and abnormal lipid membrane accumulations inside the lysosomes in PPA-treated hippocampal neuronal cells. Taken together, these findings indicate that L-serine can be utilized as a neuroprotective agent for the functionality of lysosomes through restoration of cathepsin D in disease conditions.
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Affiliation(s)
- Hyunbum Jeon
- Neural Circuit Research Group, Korea Brain Research Institute, Daegu 41062, Korea
- Department of Brain Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea
| | - Yeo Jin Kim
- Neural Circuit Research Group, Korea Brain Research Institute, Daegu 41062, Korea
| | - Su-Kyeong Hwang
- Department of Pediatrics, School of Medicine, Kyungpook National University, Daegu 41944, Korea
- Astrogen Inc., 440, Hyeoksin-daero, Dong-gu, Daegu 41072, Korea
| | - Jinsoo Seo
- Department of Brain Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea
| | - Ji Young Mun
- Neural Circuit Research Group, Korea Brain Research Institute, Daegu 41062, Korea
- Correspondence:
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27
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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: 0] [Impact Index Per Article: 0] [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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28
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Anindya R. Cytoplasmic DNA in cancer cells: Several pathways that potentially limit DNase2 and TREX1 activities. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2022; 1869:119278. [PMID: 35489653 DOI: 10.1016/j.bbamcr.2022.119278] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2022] [Revised: 04/14/2022] [Accepted: 04/19/2022] [Indexed: 06/14/2023]
Abstract
The presence of DNA in the cytoplasm of tumor cells induces the dendritic cell to produce type-I IFNs. Classically, the presence of foreign DNA in host cells' cytoplasm during viral infection elicits cGAS-STING mediated type-I IFN signaling and cytokine production. It is likely that cytosolic DNA leads to senescence and immune surveillance in transformed cells during the early stages of carcinogenesis. However, multiple factors, such as loss of cell-cycle checkpoint, mitochondrial damage and chromosomal instability, can lead to persistent accumulation of DNA in the cytoplasm of metastatic tumor cells. That is why aberrant activation of the type I IFN pathway is frequently associated with highly aggressive tumors. Intriguingly, two powerful intracellular deoxyribonucleases, DNase2 and TREX1, can target the cytoplasmic DNA for degradation. Yet the tumor cells consistently accumulate cytoplasmic DNA. This review highlights recent work connecting the lack of DNase2 and TREX1 function to innate immune signaling. It also summarizes the possible mechanisms that limit the activity of DNase2 and TREX1 in tumor cells and contributes to chronic inflammation.
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Affiliation(s)
- Roy Anindya
- Department of Biotechnology, Indian Institute of Technology Hyderabad, Kandi, Sangareddy 502284, India.
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29
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Oe Y, Kakuda K, Yoshimura SI, Hara N, Hasegawa J, Terawaki S, Kimura Y, Ikenaka K, Suetsugu S, Mochizuki H, Yoshimori T, Nakamura S. PACSIN1 is indispensable for amphisome-lysosome fusion during basal autophagy and subsets of selective autophagy. PLoS Genet 2022; 18:e1010264. [PMID: 35771772 PMCID: PMC9246181 DOI: 10.1371/journal.pgen.1010264] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 05/19/2022] [Indexed: 12/09/2022] Open
Abstract
Autophagy is an indispensable process that degrades cytoplasmic materials to maintain cellular homeostasis. During autophagy, double-membrane autophagosomes surround cytoplasmic materials and either fuse with endosomes (called amphisomes) and then lysosomes, or directly fuse with lysosomes, in both cases generating autolysosomes that degrade their contents by lysosomal hydrolases. However, it remains unclear if there are specific mechanisms and/or conditions which distinguish these alternate routes. Here, we identified PACSIN1 as a novel autophagy regulator. PACSIN1 deletion markedly decreased autophagic activity under basal nutrient-rich conditions but not starvation conditions, and led to amphisome accumulation as demonstrated by electron microscopic and co-localization analysis, indicating inhibition of lysosome fusion. PACSIN1 interacted with SNAP29, an autophagic SNARE, and was required for proper assembly of the STX17 and YKT6 complexes. Moreover, PACSIN1 was required for lysophagy, aggrephagy but not mitophagy, suggesting cargo-specific fusion mechanisms. In C. elegans, deletion of sdpn-1, a homolog of PACSINs, inhibited basal autophagy and impaired clearance of aggregated protein, implying a conserved role of PACSIN1. Taken together, our results demonstrate the amphisome-lysosome fusion process is preferentially regulated in response to nutrient state and stress, and PACSIN1 is a key to specificity during autophagy.
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Affiliation(s)
- Yukako Oe
- Laboratory of Intracellular Membrane Dynamics, Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
| | - Keita Kakuda
- Department of Neurology, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Shin-ichiro Yoshimura
- Department of Cell Biology, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Naohiro Hara
- Department of Genetics, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Junya Hasegawa
- Department of Biochemical Pathophysiology, Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan
| | - Seigo Terawaki
- Department of Molecular and Genetic Medicine, Kawasaki Medical School, Okayama, Japan
| | - Yasuyoshi Kimura
- Department of Neurology, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Kensuke Ikenaka
- Department of Neurology, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Shiro Suetsugu
- Division of Biological Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, Ikoma, Japan
- Data Science Center, Nara Institute of Science and Technology, Ikoma, Japan
- Center for Digital Green-Innovation, Nara Institute of Science and Technology, Ikoma, Japan
| | - Hideki Mochizuki
- Department of Neurology, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Tamotsu Yoshimori
- Laboratory of Intracellular Membrane Dynamics, Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
- Department of Genetics, Graduate School of Medicine, Osaka University, Osaka, Japan
- Integrated Frontier Research for Medical Science Division, Institute for Open and Transdisciplinary Research Initiatives (OTRI), Osaka University, Osaka, Japan
- * E-mail: (TY); (SN)
| | - Shuhei Nakamura
- Laboratory of Intracellular Membrane Dynamics, Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
- Department of Genetics, Graduate School of Medicine, Osaka University, Osaka, Japan
- Institute for Advanced Co-Creation Studies, Osaka University, Osaka, Japan
- * E-mail: (TY); (SN)
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30
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Endosomal v-ATPase as a Sensor Determining Myocardial Substrate Preference. Metabolites 2022; 12:metabo12070579. [PMID: 35888703 PMCID: PMC9316095 DOI: 10.3390/metabo12070579] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 06/16/2022] [Accepted: 06/20/2022] [Indexed: 11/17/2022] Open
Abstract
The heart is a metabolically flexible omnivore that can utilize a variety of substrates for energy provision. To fulfill cardiac energy requirements, the healthy adult heart mainly uses long-chain fatty acids and glucose in a balanced manner, but when exposed to physiological or pathological stimuli, it can switch its substrate preference to alternative substrates such as amino acids (AAs) and ketone bodies. Using the failing heart as an example, upon stress, the fatty acid/glucose substrate balance is upset, resulting in an over-reliance on either fatty acids or glucose. A chronic fuel shift towards a single type of substrate is linked with cardiac dysfunction. Re-balancing myocardial substrate preference is suggested as an effective strategy to rescue the failing heart. In the last decade, we revealed that vacuolar-type H+-ATPase (v-ATPase) functions as a key regulator of myocardial substrate preference and, therefore, as a novel potential treatment approach for the failing heart. Fatty acids, glucose, and AAs selectively influence the assembly state of v-ATPase resulting in modulation of its proton-pumping activity. In this review, we summarize these novel insights on v-ATPase as an integrator of nutritional information. We also describe its exploitation as a therapeutic target with focus on supplementation of AA as a nutraceutical approach to fight lipid-induced insulin resistance and contractile dysfunction of the heart.
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31
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Hooper KM, Jacquin E, Li T, Goodwin JM, Brumell JH, Durgan J, Florey O. V-ATPase is a universal regulator of LC3-associated phagocytosis and non-canonical autophagy. J Cell Biol 2022; 221:213194. [PMID: 35511089 PMCID: PMC9082624 DOI: 10.1083/jcb.202105112] [Citation(s) in RCA: 58] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Revised: 02/04/2022] [Accepted: 04/15/2022] [Indexed: 12/18/2022] Open
Abstract
Non-canonical autophagy is a key cellular pathway in immunity, cancer, and neurodegeneration, characterized by conjugation of ATG8 to endolysosomal single membranes (CASM). CASM is activated by engulfment (endocytosis, phagocytosis), agonists (STING, TRPML1), and infection (influenza), dependent on K490 in the ATG16L1 WD40-domain. However, factors associated with non-canonical ATG16L1 recruitment and CASM induction remain unknown. Here, using pharmacological inhibitors, we investigate a role for V-ATPase during non-canonical autophagy. We report that increased V0–V1 engagement is associated with, and sufficient for, CASM activation. Upon V0–V1 binding, V-ATPase recruits ATG16L1, via K490, during LC3-associated phagocytosis (LAP), STING- and drug-induced CASM, indicating a common mechanism. Furthermore, during LAP, key molecular players, including NADPH oxidase/ROS, converge on V-ATPase. Finally, we show that LAP is sensitive to Salmonella SopF, which disrupts the V-ATPase–ATG16L1 axis and provide evidence that CASM contributes to the Salmonella host response. Together, these data identify V-ATPase as a universal regulator of CASM and indicate that SopF evolved in part to evade non-canonical autophagy.
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Affiliation(s)
| | - Elise Jacquin
- Signalling Programme, Babraham Institute, Cambridge, UK.,Institut national de la santé et de la recherche médicale UMR-S 1193, Université Paris-Saclay, Châtenay-Malabry, France
| | - Taoyingnan Li
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada.,Cell Biology Program, Hospital for Sick Children, Toronto, Ontario, Canada
| | | | - John H Brumell
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada.,Cell Biology Program, Hospital for Sick Children, Toronto, Ontario, Canada.,Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada.,SickKids Inflammatory Bowel Disease Centre, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Joanne Durgan
- Signalling Programme, Babraham Institute, Cambridge, UK
| | - Oliver Florey
- Signalling Programme, Babraham Institute, Cambridge, UK
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Wang J, Onogi Y, Krueger M, Oeckl J, Karlina R, Singh I, Hauck SM, Feederle R, Li Y, Ussar S. PAT2 regulates vATPase assembly and lysosomal acidification in brown adipocytes. Mol Metab 2022; 61:101508. [PMID: 35513259 PMCID: PMC9114668 DOI: 10.1016/j.molmet.2022.101508] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Accepted: 04/26/2022] [Indexed: 11/16/2022] Open
Abstract
OBJECTIVE Brown adipocytes play a key role in maintaining body temperature as well as glucose and lipid homeostasis. However, brown adipocytes need to adapt their thermogenic activity and substrate utilization to changes in nutrient availability. Amongst the multiple factors influencing brown adipocyte activity, autophagy is an important regulatory element of thermogenic capacity and activity. Nevertheless, a specific sensing mechanism of extracellular amino acid availability linking autophagy to nutrient availability in brown adipocytes is unknown. METHODS To characterize the role of the amino acid transporter PAT2/SLC36A2 in brown adipocytes, loss or gain of function of PAT2 were studied with respect to differentiation, subcellular localization, lysosomal activity and autophagy. Activity of vATPase was evaluated by quenching of EGFP fused to LC3 or FITC-dextran loaded lysosomes in brown adipocytes upon amino acid starvation, whereas the effect of PAT2 on assembly of the vATPase was investigated by Native-PAGE. RESULTS We show that PAT2 translocates from the plasma membrane to the lysosome in response to amino acid withdrawal. Loss or overexpression of PAT2 impair lysosomal acidification and starvation induced S6K re-phosphorylation, as PAT2 facilitates the assembly of the lysosomal vATPase, by recruitment of the cytoplasmic V1 subunit to the lysosome. CONCLUSION PAT2 is an important sensor of extracellular amino acids and regulator of lysosomal acidification in brown adipocytes.
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Affiliation(s)
- Jiefu Wang
- RG Adipocytes & Metabolism, Institute for Diabetes & Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health GmbH, 85764, Neuherberg, Germany; German Center for Diabetes Research (DZD), 85764, Neuherberg, Germany
| | - Yasuhiro Onogi
- RG Adipocytes & Metabolism, Institute for Diabetes & Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health GmbH, 85764, Neuherberg, Germany; German Center for Diabetes Research (DZD), 85764, Neuherberg, Germany
| | - Martin Krueger
- Institute for Anatomy, University of Leipzig, 04103, Leipzig, Germany
| | - Josef Oeckl
- Chair for Molecular Nutritional Medicine TUM School for Life Sciences,Technical University Munich, Munich, Germany
| | - Ruth Karlina
- RG Adipocytes & Metabolism, Institute for Diabetes & Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health GmbH, 85764, Neuherberg, Germany; German Center for Diabetes Research (DZD), 85764, Neuherberg, Germany
| | - Inderjeet Singh
- RG Adipocytes & Metabolism, Institute for Diabetes & Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health GmbH, 85764, Neuherberg, Germany; German Center for Diabetes Research (DZD), 85764, Neuherberg, Germany
| | - Stefanie M Hauck
- German Center for Diabetes Research (DZD), 85764, Neuherberg, Germany; Research Unit Protein Science, Helmholtz Zentrum München, German Research Center for Environmental Health GmbH, Neuherberg, Germany
| | - Regina Feederle
- German Center for Diabetes Research (DZD), 85764, Neuherberg, Germany; Monoclonal Antibody Core Facility, Institute for Diabetes & Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health GmbH, 85764, Neuherberg, Germany
| | - Yongguo Li
- Chair for Molecular Nutritional Medicine TUM School for Life Sciences,Technical University Munich, Munich, Germany
| | - Siegfried Ussar
- RG Adipocytes & Metabolism, Institute for Diabetes & Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health GmbH, 85764, Neuherberg, Germany; German Center for Diabetes Research (DZD), 85764, Neuherberg, Germany; Department of Medicine, Technische Universität München, Munich, Germany.
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Vasanthakumar T, Keon KA, Bueler SA, Jaskolka MC, Rubinstein JL. Coordinated conformational changes in the V 1 complex during V-ATPase reversible dissociation. Nat Struct Mol Biol 2022; 29:430-439. [PMID: 35469063 DOI: 10.1038/s41594-022-00757-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Accepted: 03/03/2022] [Indexed: 11/10/2022]
Abstract
Vacuolar-type ATPases (V-ATPases) are rotary enzymes that acidify intracellular compartments in eukaryotic cells. These multi-subunit complexes consist of a cytoplasmic V1 region that hydrolyzes ATP and a membrane-embedded VO region that transports protons. V-ATPase activity is regulated by reversible dissociation of the two regions, with the isolated V1 and VO complexes becoming autoinhibited on disassembly and subunit C subsequently detaching from V1. In yeast, assembly of the V1 and VO regions is mediated by the regulator of the ATPase of vacuoles and endosomes (RAVE) complex through an unknown mechanism. We used cryogenic-electron microscopy of yeast V-ATPase to determine structures of the intact enzyme, the dissociated but complete V1 complex and the V1 complex lacking subunit C. On separation, V1 undergoes a dramatic conformational rearrangement, with its rotational state becoming incompatible for reassembly with VO. Loss of subunit C allows V1 to match the rotational state of VO, suggesting how RAVE could reassemble V1 and VO by recruiting subunit C.
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Affiliation(s)
- Thamiya Vasanthakumar
- Molecular Medicine Program, The Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Biochemistry, The University of Toronto, Toronto, Ontario, Canada
| | - Kristine A Keon
- Molecular Medicine Program, The Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Medical Biophysics, The University of Toronto, Toronto, Ontario, Canada
| | - Stephanie A Bueler
- Molecular Medicine Program, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Michael C Jaskolka
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, USA
| | - John L Rubinstein
- Molecular Medicine Program, The Hospital for Sick Children, Toronto, Ontario, Canada. .,Department of Biochemistry, The University of Toronto, Toronto, Ontario, Canada. .,Department of Medical Biophysics, The University of Toronto, Toronto, Ontario, Canada.
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Nowosad A, Besson A. Lysosomes at the Crossroads of Cell Metabolism, Cell Cycle, and Stemness. Int J Mol Sci 2022; 23:ijms23042290. [PMID: 35216401 PMCID: PMC8879101 DOI: 10.3390/ijms23042290] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 02/11/2022] [Accepted: 02/16/2022] [Indexed: 02/07/2023] Open
Abstract
Initially described as lytic bodies due to their degradative and recycling functions, lysosomes play a critical role in metabolic adaptation to nutrient availability. More recently, the contribution of lysosomal proteins to cell signaling has been established, and lysosomes have emerged as signaling hubs that regulate diverse cellular processes, including cell proliferation and cell fate. Deciphering these signaling pathways has revealed an extensive crosstalk between the lysosomal and cell cycle machineries that is only beginning to be understood. Recent studies also indicate that a number of lysosomal proteins are involved in the regulation of embryonic and adult stem cell fate and identity. In this review, we will focus on the role of the lysosome as a signaling platform with an emphasis on its function in integrating nutrient sensing with proliferation and cell cycle progression, as well as in stemness-related features, such as self-renewal and quiescence.
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Affiliation(s)
- Ada Nowosad
- Molecular, Cellular and Developmental Biology Department (MCD), Centre de Biologie Intégrative (CBI), University of Toulouse, CNRS, UPS, 31062 Toulouse, France;
- Department of Oncology, KULeuven, Laboratory for Molecular Cancer Biology, Center for Cancer Biology, VIB, 3000 Leuven, Belgium
| | - Arnaud Besson
- Molecular, Cellular and Developmental Biology Department (MCD), Centre de Biologie Intégrative (CBI), University of Toulouse, CNRS, UPS, 31062 Toulouse, France;
- Correspondence: ; Tel.: +33-561558486
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Khan MM, Lee S, Couoh‐Cardel S, Oot RA, Kim H, Wilkens S, Roh S. Oxidative stress protein Oxr1 promotes V-ATPase holoenzyme disassembly in catalytic activity-independent manner. EMBO J 2022; 41:e109360. [PMID: 34918374 PMCID: PMC8804929 DOI: 10.15252/embj.2021109360] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Revised: 10/30/2021] [Accepted: 11/15/2021] [Indexed: 11/09/2022] Open
Abstract
The vacuolar ATPase (V-ATPase) is a rotary motor proton pump that is regulated by an assembly equilibrium between active holoenzyme and autoinhibited V1 -ATPase and Vo proton channel subcomplexes. Here, we report cryo-EM structures of yeast V-ATPase assembled in vitro from lipid nanodisc reconstituted Vo and mutant V1 . Our analysis identified holoenzymes in three active rotary states, indicating that binding of V1 to Vo provides sufficient free energy to overcome Vo autoinhibition. Moreover, the structures suggest that the unequal spacing of Vo 's proton-carrying glutamic acid residues serves to alleviate the symmetry mismatch between V1 and Vo motors, a notion that is supported by mutagenesis experiments. We also uncover a structure of free V1 bound to Oxr1, a conserved but poorly characterized factor involved in the oxidative stress response. Biochemical experiments show that Oxr1 inhibits V1 -ATPase and causes disassembly of the holoenzyme, suggesting that Oxr1 plays a direct role in V-ATPase regulation.
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Affiliation(s)
- Md. Murad Khan
- Department of Biochemistry and Molecular BiologySUNY Upstate Medical UniversitySyracuseNYUSA
| | - Seowon Lee
- School of Biological ScienceInstitute of Molecular Biology and GeneticsSeoul National UniversitySeoulSouth Korea
| | - Sergio Couoh‐Cardel
- Department of Biochemistry and Molecular BiologySUNY Upstate Medical UniversitySyracuseNYUSA
- Present address:
Department of Molecular and Cellular PhysiologyStanford UniversityStanfordCAUSA
| | - Rebecca A Oot
- Department of Biochemistry and Molecular BiologySUNY Upstate Medical UniversitySyracuseNYUSA
| | - Hyunmin Kim
- School of Biological ScienceInstitute of Molecular Biology and GeneticsSeoul National UniversitySeoulSouth Korea
| | - Stephan Wilkens
- Department of Biochemistry and Molecular BiologySUNY Upstate Medical UniversitySyracuseNYUSA
| | - Soung‐Hun Roh
- School of Biological ScienceInstitute of Molecular Biology and GeneticsSeoul National UniversitySeoulSouth Korea
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Chen F, Kang R, Liu J, Tang D. The V-ATPases in cancer and cell death. Cancer Gene Ther 2022; 29:1529-1541. [PMID: 35504950 PMCID: PMC9063253 DOI: 10.1038/s41417-022-00477-y] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 04/07/2022] [Accepted: 04/21/2022] [Indexed: 02/04/2023]
Abstract
Transmembrane ATPases are membrane-bound enzyme complexes and ion transporters that can be divided into F-, V-, and A-ATPases according to their structure. The V-ATPases, also known as H+-ATPases, are large multi-subunit protein complexes composed of a peripheral domain (V1) responsible for the hydrolysis of ATP and a membrane-integrated domain (V0) that transports protons across plasma membrane or organelle membrane. V-ATPases play a fundamental role in maintaining pH homeostasis through lysosomal acidification and are involved in modulating various physiological and pathological processes, such as macropinocytosis, autophagy, cell invasion, and cell death (e.g., apoptosis, anoikis, alkaliptosis, ferroptosis, and lysosome-dependent cell death). In addition to participating in embryonic development, V-ATPase pathways, when dysfunctional, are implicated in human diseases, such as neurodegenerative diseases, osteopetrosis, distal renal tubular acidosis, and cancer. In this review, we summarize the structure and regulation of isoforms of V-ATPase subunits and discuss their context-dependent roles in cancer biology and cell death. Updated knowledge about V-ATPases may enable us to design new anticancer drugs or strategies.
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Affiliation(s)
- Fangquan Chen
- grid.417009.b0000 0004 1758 4591DAMP Laboratory, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong 510120 China
| | - Rui Kang
- grid.267313.20000 0000 9482 7121Department of Surgery, University of Texas Southwestern Medical Center, Dallas, TX 75390 USA
| | - Jiao Liu
- grid.417009.b0000 0004 1758 4591DAMP Laboratory, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong 510120 China
| | - Daolin Tang
- grid.267313.20000 0000 9482 7121Department of Surgery, University of Texas Southwestern Medical Center, Dallas, TX 75390 USA
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Gutiérrez-Pérez P, Santillán EM, Lendl T, Wang J, Schrempf A, Steinacker TL, Asparuhova M, Brandstetter M, Haselbach D, Cochella L. miR-1 sustains muscle physiology by controlling V-ATPase complex assembly. SCIENCE ADVANCES 2021; 7:eabh1434. [PMID: 34652942 PMCID: PMC8519577 DOI: 10.1126/sciadv.abh1434] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Accepted: 08/23/2021] [Indexed: 05/13/2023]
Abstract
Muscle function requires unique structural and metabolic adaptations that can render muscle cells selectively vulnerable, with mutations in some ubiquitously expressed genes causing myopathies but sparing other tissues. We uncovered a muscle cell vulnerability by studying miR-1, a deeply conserved, muscle-specific microRNA whose ablation causes various muscle defects. Using Caenorhabditis elegans, we found that miR-1 represses multiple subunits of the ubiquitous vacuolar adenosine triphosphatase (V-ATPase) complex, which is essential for internal compartment acidification and metabolic signaling. V-ATPase subunits are predicted miR-1 targets in animals ranging from C. elegans to humans, and we experimentally validated this in Drosophila. Unexpectedly, up-regulation of V-ATPase subunits upon miR-1 deletion causes reduced V-ATPase function due to defects in complex assembly. These results reveal V-ATPase assembly as a conserved muscle cell vulnerability and support a previously unknown role for microRNAs in the regulation of protein complexes.
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Affiliation(s)
- Paula Gutiérrez-Pérez
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), 1030 Vienna, Austria
- Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and Medical University of Vienna, 1030 Vienna, Austria
| | - Emilio M. Santillán
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), 1030 Vienna, Austria
- Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and Medical University of Vienna, 1030 Vienna, Austria
| | - Thomas Lendl
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), 1030 Vienna, Austria
| | - Jingkui Wang
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), 1030 Vienna, Austria
| | - Anna Schrempf
- Research Center for Molecular Medicine of the Austrian Academy of Sciences, 1090 Vienna, Austria
| | | | - Mila Asparuhova
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), 1030 Vienna, Austria
| | - Marlene Brandstetter
- Electron Microscopy Facility, Vienna BioCenter Core Facilities GmbH, Vienna, Austria
| | - David Haselbach
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), 1030 Vienna, Austria
| | - Luisa Cochella
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), 1030 Vienna, Austria
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Wang S, Schianchi F, Neumann D, Wong LY, Sun A, van Nieuwenhoven FA, Zeegers MP, Strzelecka A, Col U, Glatz JFC, Nabben M, Luiken JJFP. Specific amino acid supplementation rescues the heart from lipid overload-induced insulin resistance and contractile dysfunction by targeting the endosomal mTOR-v-ATPase axis. Mol Metab 2021; 53:101293. [PMID: 34265467 PMCID: PMC8350375 DOI: 10.1016/j.molmet.2021.101293] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 07/05/2021] [Accepted: 07/07/2021] [Indexed: 01/25/2023] Open
Abstract
Objective The diabetic heart is characterized by extensive lipid accumulation which often leads to cardiac contractile dysfunction. The underlying mechanism involves a pivotal role for vacuolar-type H+-ATPase (v-ATPase, functioning as endosomal/lysosomal proton pump). Specifically, lipid oversupply to the heart causes disassembly of v-ATPase and endosomal deacidification. Endosomes are storage compartments for lipid transporter CD36. However, upon endosomal deacidification, CD36 is expelled to translocate to the sarcolemma, thereby inducing myocardial lipid accumulation, insulin resistance, and contractile dysfunction. Hence, the v-ATPase assembly may be a suitable target for ameliorating diabetic cardiomyopathy. Another function of v-ATPase involves the binding of anabolic master-regulator mTORC1 to endosomes, a prerequisite for the activation of mTORC1 by amino acids (AAs). We examined whether the relationship between v-ATPase and mTORC1 also operates reciprocally; specifically, whether AA induces v-ATPase reassembly in a mTORC1-dependent manner to prevent excess lipids from entering and damaging the heart. Methods Lipid overexposed rodent/human cardiomyocytes and high-fat diet-fed rats were treated with a specific cocktail of AAs (lysine/leucine/arginine). Then, v-ATPase assembly status/activity, cell surface CD36 content, myocellular lipid uptake/accumulation, insulin sensitivity, and contractile function were measured. To elucidate underlying mechanisms, specific gene knockdown was employed, followed by subcellular fractionation, and coimmunoprecipitation. Results In lipid-overexposed cardiomyocytes, lysine/leucine/arginine reinternalized CD36 to the endosomes, prevented/reversed lipid accumulation, preserved/restored insulin sensitivity, and contractile function. These beneficial AA actions required the mTORC1–v-ATPase axis, adaptor protein Ragulator, and endosomal/lysosomal AA transporter SLC38A9, indicating an endosome-centric inside-out AA sensing mechanism. In high-fat diet-fed rats, lysine/leucine/arginine had similar beneficial actions at the myocellular level as in vitro in lipid-overexposed cardiomyocytes and partially reversed cardiac hypertrophy. Conclusion Specific AAs acting through v-ATPase reassembly reduce cardiac lipid uptake raising the possibility for treatment in situations of lipid overload and associated insulin resistance. • High physiological concentrations of specific AAs (K/L/R) activate v-ATPase. • The KLR mix activates v-ATPase by mutually dependent activation of mTORC1. • KLR-induced v-ATPase activation enables endosomes to retain lipid transporter CD36. • KLR mends lipid-induced insulin resistance and cardiomyocytic contractile dysfunction. • KLR reverses v-ATPase disassembly and cardiac hypertrophy in high-fat diet-fed rats.
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Affiliation(s)
- Shujin Wang
- Department of Genetics & Cell Biology, Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, the Netherlands; Institute of Life Sciences, Chongqing Medical University, Chongqing, PR China
| | - Francesco Schianchi
- Department of Genetics & Cell Biology, Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, the Netherlands
| | - Dietbert Neumann
- Department of Pathology, Maastricht University Medical Center+, Maastricht, the Netherlands; CARIM School for Cardiovascular Diseases, Maastricht, the Netherlands
| | - Li-Yen Wong
- Department of Clinical Genetics, Maastricht University Medical Center+, Maastricht, the Netherlands
| | - Aomin Sun
- Department of Genetics & Cell Biology, Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, the Netherlands
| | - Frans A van Nieuwenhoven
- Department of Physiology, Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, the Netherlands; CARIM School for Cardiovascular Diseases, Maastricht, the Netherlands
| | - Maurice P Zeegers
- Department of Complex Genetics and Epidemiology, School of Nutrition and Translational Research in Metabolism, Maastricht University, Maastricht, the Netherlands
| | - Agnieszka Strzelecka
- Department of Genetics & Cell Biology, Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, the Netherlands
| | - Umare Col
- Department of Genetics & Cell Biology, Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, the Netherlands
| | - Jan F C Glatz
- Department of Genetics & Cell Biology, Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, the Netherlands; Department of Clinical Genetics, Maastricht University Medical Center+, Maastricht, the Netherlands
| | - Miranda Nabben
- Department of Genetics & Cell Biology, Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, the Netherlands; Department of Clinical Genetics, Maastricht University Medical Center+, Maastricht, the Netherlands; CARIM School for Cardiovascular Diseases, Maastricht, the Netherlands
| | - Joost J F P Luiken
- Department of Genetics & Cell Biology, Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, the Netherlands; Department of Clinical Genetics, Maastricht University Medical Center+, Maastricht, the Netherlands.
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Chu A, Zirngibl RA, Manolson MF. The V-ATPase a3 Subunit: Structure, Function and Therapeutic Potential of an Essential Biomolecule in Osteoclastic Bone Resorption. Int J Mol Sci 2021; 22:ijms22136934. [PMID: 34203247 PMCID: PMC8269383 DOI: 10.3390/ijms22136934] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 06/18/2021] [Accepted: 06/21/2021] [Indexed: 12/29/2022] Open
Abstract
This review focuses on one of the 16 proteins composing the V-ATPase complex responsible for resorbing bone: the a3 subunit. The rationale for focusing on this biomolecule is that mutations in this one protein account for over 50% of osteopetrosis cases, highlighting its critical role in bone physiology. Despite its essential role in bone remodeling and its involvement in bone diseases, little is known about the way in which this subunit is targeted and regulated within osteoclasts. To this end, this review is broadened to include the three other mammalian paralogues (a1, a2 and a4) and the two yeast orthologs (Vph1p and Stv1p). By examining the literature on all of the paralogues/orthologs of the V-ATPase a subunit, we hope to provide insight into the molecular mechanisms and future research directions specific to a3. This review starts with an overview on bone, highlighting the role of V-ATPases in osteoclastic bone resorption. We then cover V-ATPases in other location/functions, highlighting the roles which the four mammalian a subunit paralogues might play in differential targeting and/or regulation. We review the ways in which the energy of ATP hydrolysis is converted into proton translocation, and go in depth into the diverse role of the a subunit, not only in proton translocation but also in lipid binding, cell signaling and human diseases. Finally, the therapeutic implication of targeting a3 specifically for bone diseases and cancer is discussed, with concluding remarks on future directions.
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Jaskolka MC, Winkley SR, Kane PM. RAVE and Rabconnectin-3 Complexes as Signal Dependent Regulators of Organelle Acidification. Front Cell Dev Biol 2021; 9:698190. [PMID: 34249946 PMCID: PMC8264551 DOI: 10.3389/fcell.2021.698190] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 05/28/2021] [Indexed: 12/12/2022] Open
Abstract
The yeast RAVE (Regulator of H+-ATPase of Vacuolar and Endosomal membranes) complex and Rabconnectin-3 complexes of higher eukaryotes regulate acidification of organelles such as lysosomes and endosomes by catalyzing V-ATPase assembly. V-ATPases are highly conserved proton pumps consisting of a peripheral V1 subcomplex that contains the sites of ATP hydrolysis, attached to an integral membrane Vo subcomplex that forms the transmembrane proton pore. Reversible disassembly of the V-ATPase is a conserved regulatory mechanism that occurs in response to multiple signals, serving to tune ATPase activity and compartment acidification to changing extracellular conditions. Signals such as glucose deprivation can induce release of V1 from Vo, which inhibits both ATPase activity and proton transport. Reassembly of V1 with Vo restores ATP-driven proton transport, but requires assistance of the RAVE or Rabconnectin-3 complexes. Glucose deprivation triggers V-ATPase disassembly in yeast and is accompanied by binding of RAVE to V1 subcomplexes. Upon glucose readdition, RAVE catalyzes both recruitment of V1 to the vacuolar membrane and its reassembly with Vo. The RAVE complex can be recruited to the vacuolar membrane by glucose in the absence of V1 subunits, indicating that the interaction between RAVE and the Vo membrane domain is glucose-sensitive. Yeast RAVE complexes also distinguish between organelle-specific isoforms of the Vo a-subunit and thus regulate distinct V-ATPase subpopulations. Rabconnectin-3 complexes in higher eukaryotes appear to be functionally equivalent to yeast RAVE. Originally isolated as a two-subunit complex from rat brain, the Rabconnectin-3 complex has regions of homology with yeast RAVE and was shown to interact with V-ATPase subunits and promote endosomal acidification. Current understanding of the structure and function of RAVE and Rabconnectin-3 complexes, their interactions with the V-ATPase, their role in signal-dependent modulation of organelle acidification, and their impact on downstream pathways will be discussed.
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Affiliation(s)
- Michael C Jaskolka
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, United States
| | - Samuel R Winkley
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, United States
| | - Patricia M Kane
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, United States
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Seibert M, Kurrle N, Schnütgen F, Serve H. Amino acid sensory complex proteins in mTORC1 and macroautophagy regulation. Matrix Biol 2021; 100-101:65-83. [DOI: 10.1016/j.matbio.2021.01.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 01/02/2021] [Accepted: 01/02/2021] [Indexed: 12/15/2022]
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Ponsford AH, Ryan TA, Raimondi A, Cocucci E, Wycislo SA, Fröhlich F, Swan LE, Stagi M. Live imaging of intra-lysosome pH in cell lines and primary neuronal culture using a novel genetically encoded biosensor. Autophagy 2021; 17:1500-1518. [PMID: 32515674 PMCID: PMC8205096 DOI: 10.1080/15548627.2020.1771858] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 05/06/2020] [Accepted: 05/09/2020] [Indexed: 12/11/2022] Open
Abstract
Disorders of lysosomal physiology have increasingly been found to underlie the pathology of a rapidly growing cast of neurodevelopmental disorders and sporadic diseases of aging. One cardinal aspect of lysosomal (dys)function is lysosomal acidification in which defects trigger lysosomal stress signaling and defects in proteolytic capacity. We have developed a genetically encoded ratiometric probe to measure lysosomal pH coupled with a purification tag to efficiently purify lysosomes for both proteomic and in vitro evaluation of their function. Using our probe, we showed that lysosomal pH is remarkably stable over a period of days in a variety of cell types. Additionally, this probe can be used to determine that lysosomal stress signaling via TFEB is uncoupled from gross changes in lysosomal pH. Finally, we demonstrated that while overexpression of ARL8B GTPase causes striking alkalinization of peripheral lysosomes in HEK293 T cells, peripheral lysosomes per se are no less acidic than juxtanuclear lysosomes in our cell lines.Abbreviations: ARL8B: ADP ribosylation factor like GTPase 8B; ATP: adenosine triphosphate; ATP5F1B/ATPB: ATP synthase F1 subunit beta; ATP6V1A: ATPase H+ transporting V1 subunit A; Baf: bafilomycin A1; BLOC-1: biogenesis of lysosome-related organelles complex 1; BSA: bovine serum albumin; Cos7: African green monkey kidney fibroblast-like cell line; CQ: chloroquine; CTSB: cathepsin B; CYCS: cytochrome c, somatic; DAPI: 4',6-diamidino -2- phenylindole; DIC: differential interference contrast; DIV: days in vitro; DMEM: Dulbecco's modified Eagle's medium; E8: embryonic day 8; EEA1: early endosome antigen 1; EGTA: ethylene glycol-bis(β-aminoethyl ether)-N,N,N',N'-tetraacetic acid; ER: endoplasmic reticulum; FBS: fetal bovine serum; FITC: fluorescein isothiocyanate; GABARAPL2: GABA type A receptor associated protein like 2; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; GOLGA2/GM130: golgin A2; GTP: guanosine triphosphate; HEK293T: human embryonic kidney 293 cells, that expresses a mutant version of the SV40 large T antigen; HeLa: Henrietta Lacks-derived cell; HEPES: 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid; HRP: horseradish peroxidase; IGF2R/ciM6PR: insulin like growth factor 2 receptor; LAMP1/2: lysosomal associated membrane protein 1/2; LMAN2/VIP36: lectin, mannose binding 2; MAP1LC3/LC3: microtubule-associated protein 1 light chain 3; MTORC1: mechanistic target of rapamycin kinase complex 1; PCR: polymerase chain reaction; PDL: poly-d-lysine; PGK1p: promotor from human phosphoglycerate kinase 1; PIKFYVE: phosphoinositide kinase, FYVE-type zinc finger containing; PPT1/CLN1: palmitoyl-protein thioesterase 1; RPS6KB1/p70: ribosomal protein S6 kinase B1; STAT3: signal transducer and activator of transcription 3; TAX1BP1: Tax1 binding protein 1; TFEB: transcription factor EB; TGN: trans-Golgi network; TGOLN2/TGN46: trans-Golgi network protein 2; TIRF: total internal reflection fluorescence; TMEM106B: transmembrane protein 106B; TOR: target of rapamycin; TRPM2: transient receptor potential cation channel subfamily M member 2; V-ATPase: vacuolar-type proton-translocating ATPase; VPS35: VPS35 retromer complex component.
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Affiliation(s)
- Amy H. Ponsford
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, UK
| | - Thomas A. Ryan
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, UK
| | - Andrea Raimondi
- Experimental Imaging Center, San Raffaele Scientific Institute, Milan, Italy
| | - Emanuele Cocucci
- Division of Pharmaceutics and Pharmacology, College of Pharmacy and the Comprehensive Cancer Center, The Ohio State University, Columbus, OH, USA
| | - Susanne A. Wycislo
- Department of Biology/Chemistry, Molecular Membrane Biology Group, University of Osnabrück, Osnabrück, Germany
| | - Florian Fröhlich
- Department of Biology/Chemistry, Molecular Membrane Biology Group, University of Osnabrück, Osnabrück, Germany
- Centre of Cellular Nanoanalytics (CellNanOs), University of Osnabrück, Osnabrück, Osnabrück, Germany
| | - Laura E. Swan
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, UK
| | - Massimiliano Stagi
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, UK
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43
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Jaskolka MC, Tarsio M, Smardon AM, Khan MM, Kane PM. Defining steps in RAVE-catalyzed V-ATPase assembly using purified RAVE and V-ATPase subcomplexes. J Biol Chem 2021; 296:100703. [PMID: 33895134 PMCID: PMC8138766 DOI: 10.1016/j.jbc.2021.100703] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 04/20/2021] [Accepted: 04/21/2021] [Indexed: 12/30/2022] Open
Abstract
The vacuolar H+-ATPase (V-ATPase) is a highly conserved proton pump responsible for the acidification of intracellular organelles in virtually all eukaryotic cells. V-ATPases are regulated by the rapid and reversible disassembly of the peripheral V1 domain from the integral membrane Vo domain, accompanied by release of the V1 C subunit from both domains. Efficient reassembly of V-ATPases requires the Regulator of the H+-ATPase of Vacuoles and Endosomes (RAVE) complex in yeast. Although a number of pairwise interactions between RAVE and V-ATPase subunits have been mapped, the low endogenous levels of the RAVE complex and lethality of constitutive RAV1 overexpression have hindered biochemical characterization of the intact RAVE complex. We describe a novel inducible overexpression system that allows purification of native RAVE and RAVE–V1 complexes. Both purified RAVE and RAVE–V1 contain substoichiometric levels of subunit C. RAVE–V1 binds tightly to expressed subunit C in vitro, but binding of subunit C to RAVE alone is weak. Neither RAVE nor RAVE–V1 interacts with the N-terminal domain of Vo subunit Vph1 in vitro. RAVE–V1 complexes, like isolated V1, have no MgATPase activity, suggesting that RAVE cannot reverse V1 inhibition generated by rotation of subunit H and entrapment of MgADP that occur upon disassembly. However, purified RAVE can accelerate reassembly of V1 carrying a mutant subunit H incapable of inhibition with Vo complexes reconstituted into lipid nanodiscs, consistent with its catalytic activity in vivo. These results provide new insights into the possible order of events in V-ATPase reassembly and the roles of the RAVE complex in each event.
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Affiliation(s)
- Michael C Jaskolka
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, New York, USA
| | - Maureen Tarsio
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, New York, USA
| | - Anne M Smardon
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, New York, USA
| | - Md Murad Khan
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, New York, USA
| | - Patricia M Kane
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, New York, USA.
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Paquette M, El-Houjeiri L, C Zirden L, Puustinen P, Blanchette P, Jeong H, Dejgaard K, Siegel PM, Pause A. AMPK-dependent phosphorylation is required for transcriptional activation of TFEB and TFE3. Autophagy 2021; 17:3957-3975. [PMID: 33734022 DOI: 10.1080/15548627.2021.1898748] [Citation(s) in RCA: 86] [Impact Index Per Article: 28.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Increased macroautophagy/autophagy and lysosomal activity promote tumor growth, survival and chemo-resistance. During acute starvation, autophagy is rapidly engaged by AMPK (AMP-activated protein kinase) activation and MTOR (mechanistic target of rapamycin kinase) complex 1 (MTORC1) inhibition to maintain energy homeostasis and cell survival. TFEB (transcription factor E3) and TFE3 (transcription factor binding to IGHM enhancer 3) are master transcriptional regulators of autophagy and lysosomal activity and their cytoplasm/nuclear shuttling is controlled by MTORC1-dependent multisite phosphorylation. However, it is not known whether and how the transcriptional activity of TFEB or TFE3 is regulated. We show that AMPK mediates phosphorylation of TFEB and TFE3 on three serine residues, leading to TFEB and TFE3 transcriptional activity upon nutrient starvation, FLCN (folliculin) depletion and pharmacological manipulation of MTORC1 or AMPK. Collectively, we show that MTORC1 specifically controls TFEB and TFE3 cytosolic retention, whereas AMPK is essential for TFEB and TFE3 transcriptional activity. This dual and opposing regulation of TFEB and TFE3 by MTORC1 and AMPK is reminiscent of the regulation of another critical regulator of autophagy, ULK1 (unc-51 like autophagy activating kinase 1). Surprisingly, we show that chemoresistance is mediated by AMPK-dependent activation of TFEB, which is abolished by pharmacological inhibition of AMPK or mutation of serine 466, 467 and 469 to alanine residues within TFEB. Altogether, we show that AMPK is a key regulator of TFEB and TFE3 transcriptional activity, and we validate AMPK as a promising target in cancer therapy to evade chemotherapeutic resistance.AbbreviationsACACA: acetyl-CoA carboxylase alpha; ACTB: actin beta; AICAR: 5-aminoimidazole-4-carboxamide ribonucleotide; AMPK: AMP-activated protein kinase; AMPKi: AMPK inhibitor, SBI-0206965; CA: constitutively active; CARM1: coactivator-associated arginine methyltransferase 1; CFP: cyan fluorescent protein; CLEAR: coordinated lysosomal expression and regulation; DKO: double knock-out; DMEM: Dulbecco's modified Eagle's medium; DMSO: dimethyl sulfoxide; DQ-BSA: self-quenched BODIPY® dye conjugates of bovine serum albumin; EBSS: Earle's balanced salt solution; FLCN: folliculin; GFP: green fluorescent protein; GST: glutathione S-transferases; HD: Huntington disease; HTT: huntingtin; KO: knock-out; LAMP1: lysosomal associated membrane protein 1; MEF: mouse embryonic fibroblasts; MITF: melanocyte inducing transcription factor; MTORC1: MTOR complex 1; PolyQ: polyglutamine; RPS6: ribosomal protein S6; RT-qPCR: reverse transcription quantitative polymerase chain reaction; TCL: total cell lysates; TFE3: transcription factor binding to IGHM enhancer 3; TFEB: transcription factor EB; TKO: triple knock-out; ULK1: unc-51 like autophagy activating kinase 1.
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Affiliation(s)
- Mathieu Paquette
- Goodman Cancer Research Center, McGill University, Montréal, Québec, Canada.,Department of Biochemistry, McGill University, Montréal, Québec, Canada
| | - Leeanna El-Houjeiri
- Goodman Cancer Research Center, McGill University, Montréal, Québec, Canada.,Department of Biochemistry, McGill University, Montréal, Québec, Canada
| | - Linda C Zirden
- Goodman Cancer Research Center, McGill University, Montréal, Québec, Canada.,Department of Biochemistry, McGill University, Montréal, Québec, Canada
| | - Pietri Puustinen
- Cell Death and Metabolism, Danish Cancer Society Research Center (DCRC), Copenhagen, Denmark
| | - Paola Blanchette
- Goodman Cancer Research Center, McGill University, Montréal, Québec, Canada.,Department of Biochemistry, McGill University, Montréal, Québec, Canada
| | - Hyeonju Jeong
- Goodman Cancer Research Center, McGill University, Montréal, Québec, Canada.,Department of Biochemistry, McGill University, Montréal, Québec, Canada
| | - Kurt Dejgaard
- Department of Biochemistry, McGill University, Montréal, Québec, Canada
| | - Peter M Siegel
- Goodman Cancer Research Center, McGill University, Montréal, Québec, Canada.,Department of Biochemistry, McGill University, Montréal, Québec, Canada.,Department of Medicine, McGill University, Montréal, Québec, Canada
| | - Arnim Pause
- Goodman Cancer Research Center, McGill University, Montréal, Québec, Canada.,Department of Biochemistry, McGill University, Montréal, Québec, Canada
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45
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Eaton AF, Merkulova M, Brown D. The H +-ATPase (V-ATPase): from proton pump to signaling complex in health and disease. Am J Physiol Cell Physiol 2020; 320:C392-C414. [PMID: 33326313 PMCID: PMC8294626 DOI: 10.1152/ajpcell.00442.2020] [Citation(s) in RCA: 73] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
A primary function of the H+-ATPase (or V-ATPase) is to create an electrochemical proton gradient across eukaryotic cell membranes, which energizes fundamental cellular processes. Its activity allows for the acidification of intracellular vesicles and organelles, which is necessary for many essential cell biological events to occur. In addition, many specialized cell types in various organ systems such as the kidney, bone, male reproductive tract, inner ear, olfactory mucosa, and more, use plasma membrane V-ATPases to perform specific activities that depend on extracellular acidification. It is, however, increasingly apparent that V-ATPases are central players in many normal and pathophysiological processes that directly influence human health in many different and sometimes unexpected ways. These include cancer, neurodegenerative diseases, diabetes, and sensory perception, as well as energy and nutrient-sensing functions within cells. This review first covers the well-established role of the V-ATPase as a transmembrane proton pump in the plasma membrane and intracellular vesicles and outlines factors contributing to its physiological regulation in different cell types. This is followed by a discussion of the more recently emerging unconventional roles for the V-ATPase, such as its role as a protein interaction hub involved in cell signaling, and the (patho)physiological implications of these interactions. Finally, the central importance of endosomal acidification and V-ATPase activity on viral infection will be discussed in the context of the current COVID-19 pandemic.
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Affiliation(s)
- Amity F Eaton
- Program in Membrane Biology and Division of Nephrology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - Maria Merkulova
- Program in Membrane Biology and Division of Nephrology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - Dennis Brown
- Program in Membrane Biology and Division of Nephrology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
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46
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TRPM2 promotes autophagic degradation in vascular smooth muscle cells. Sci Rep 2020; 10:20719. [PMID: 33244095 PMCID: PMC7693237 DOI: 10.1038/s41598-020-77620-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Accepted: 11/13/2020] [Indexed: 01/08/2023] Open
Abstract
Transient receptor potential channel M2 (TRPM2) is a Ca2+-permeable channel that is activated by reactive oxygen species (ROS). In many cell types, ROS activate TRPM2 to induce excessive Ca2+ influx, resulting in Ca2+ overload and consequent cell death. Recent studies suggest that TRPM2 may also regulate autophagy in pericytes and cancer cells by acting on the early step of autophagy, i.e. autophagic induction. However, there is no report on the role of TRPM2 in autophagic degradation, which is the late stage of autophagy. In the present study, we found abundant TRPM2 expression in lysosomes/autolysosomes in the primary cultured mouse aortic smooth muscle cells (mASMCs). Nutrient starvation stimulated autophagic flux in mASMCs mainly by promoting autophagic degradation. This starvation-induced autophagic degradation was reduced by TRPM2 knockout. Importantly, starvation-induced lysosomal/autolysosomal acidification and cell death were also substantially reduced by TRPM2 knockout. Taken together, the present study uncovered a novel mechanism that lysosomal TRPM2 facilitates lysosomal acidification to stimulate excessive autolysosome degradation and consequent cell death.
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47
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Pathak M, Lal G. The Regulatory Function of CCR9 + Dendritic Cells in Inflammation and Autoimmunity. Front Immunol 2020; 11:536326. [PMID: 33123124 PMCID: PMC7566413 DOI: 10.3389/fimmu.2020.536326] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Accepted: 08/13/2020] [Indexed: 12/26/2022] Open
Abstract
Chemokine receptor CCR9 is a G protein–coupled receptor and expressed on several types of immune cells, including dendritic cells (DCs), CD4+ T cells, and B cells. CCR9 drives the migration of immune cells to gradients of its cognate ligand CCL25. The chemokine CCL25 is mostly produced by gut and thymic epithelial cells. Gut- and thymic-homing DCs are known to express CCR9, and these cells are predominantly localized in the gut lining and thymus. CCR9+ DCs are implicated in regulating inflammation, food allergy, alloimmunity, and autoimmunity. Differential interaction of CCR9+ DCs with lymphoid and myeloid cells in the thymus, secondary lymphoid tissues, and mucosal sites offer crucial insights to immune regulation. In this review, we examine the phenotypes, distributions, and interactions of CCR9+ DCs with other immune cells, elucidating their functions and role in inflammation and autoimmunity.
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Affiliation(s)
- Manisha Pathak
- Laboratory of Autoimmunity and Tolerance, National Centre for Cell Science, Pune, India
| | - Girdhari Lal
- Laboratory of Autoimmunity and Tolerance, National Centre for Cell Science, Pune, India
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48
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Lysosome as a Central Hub for Rewiring PH Homeostasis in Tumors. Cancers (Basel) 2020; 12:cancers12092437. [PMID: 32867178 PMCID: PMC7565471 DOI: 10.3390/cancers12092437] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 08/18/2020] [Accepted: 08/21/2020] [Indexed: 02/06/2023] Open
Abstract
Cancer cells generate large quantities of cytoplasmic protons as byproducts of aberrantly activated aerobic glycolysis and lactate fermentation. To avoid potentially detrimental acidification of the intracellular milieu, cancer cells activate multiple acid-removal pathways that promote cytosolic alkalization and extracellular acidification. Accumulating evidence suggests that in addition to the well-characterized ion pumps and exchangers in the plasma membrane, cancer cell lysosomes are also reprogrammed for this purpose. On the one hand, the increased expression and activity of the vacuolar-type H+-ATPase (V-ATPase) on the lysosomal limiting membrane combined with the larger volume of the lysosomal compartment increases the lysosomal proton storage capacity substantially. On the other hand, enhanced lysosome exocytosis enables the efficient release of lysosomal protons to the extracellular space. Together, these two steps dynamically drive proton flow from the cytosol to extracellular space. In this perspective, we provide mechanistic insight into how lysosomes contribute to the rewiring of pH homeostasis in cancer cells.
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49
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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: 2.8] [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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50
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Banerjee S, Kane PM. Regulation of V-ATPase Activity and Organelle pH by Phosphatidylinositol Phosphate Lipids. Front Cell Dev Biol 2020; 8:510. [PMID: 32656214 PMCID: PMC7324685 DOI: 10.3389/fcell.2020.00510] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 05/28/2020] [Indexed: 12/14/2022] Open
Abstract
Luminal pH and the distinctive distribution of phosphatidylinositol phosphate (PIP) lipids are central identifying features of organelles in all eukaryotic cells that are also critical for organelle function. V-ATPases are conserved proton pumps that populate and acidify multiple organelles of the secretory and the endocytic pathway. Complete loss of V-ATPase activity causes embryonic lethality in higher animals and conditional lethality in yeast, while partial loss of V-ATPase function is associated with multiple disease states. On the other hand, many cancer cells increase their virulence by upregulating V-ATPase expression and activity. The pH of individual organelles is tightly controlled and essential for function, but the mechanisms for compartment-specific pH regulation are not completely understood. There is substantial evidence indicating that the PIP content of membranes influences organelle pH. We present recent evidence that PIPs interact directly with subunit isoforms of the V-ATPase to dictate localization of V-ATPase subpopulations and participate in their regulation. In yeast cells, which have only one set of organelle-specific V-ATPase subunit isoforms, the Golgi-enriched lipid PI(4)P binds to the cytosolic domain of the Golgi-enriched a-subunit isoform Stv1, and loss of PI(4)P binding results in mislocalization of Stv1-containing V-ATPases from the Golgi to the vacuole/lysosome. In contrast, levels of the vacuole/lysosome-enriched signaling lipid PI(3,5)P2 affect assembly and activity of V-ATPases containing the Vph1 a-subunit isoform. Mutations in the Vph1 isoform that disrupt the lipid interaction increase sensitivity to stress. These studies have decoded “zip codes” for PIP lipids in the cytosolic N-terminal domain of the a-subunit isoforms of the yeast V-ATPase, and similar interactions between PIP lipids and the V-ATPase subunit isoforms are emerging in higher eukaryotes. In addition to direct effects on the V-ATPase, PIP lipids are also likely to affect organelle pH indirectly, through interactions with other membrane transporters. We discuss direct and indirect effects of PIP lipids on organelle pH, and the functional consequences of the interplay between PIP lipid content and organelle pH.
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Affiliation(s)
- Subhrajit Banerjee
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, United States
| | - Patricia M Kane
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, United States
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