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Xiao G, Li X, Yang H, Zhang R, Huang J, Tian Y, Nie M, Sun X. mTOR mutation disrupts larval zebrafish tail fin regeneration via regulating proliferation of blastema cells and mitochondrial functions. J Orthop Surg Res 2024; 19:321. [PMID: 38812038 PMCID: PMC11134885 DOI: 10.1186/s13018-024-04802-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2024] [Accepted: 05/21/2024] [Indexed: 05/31/2024] Open
Abstract
BACKGROUND The larval zebrafish tail fin can completely regenerate in 3 days post amputation. mTOR, the main regulator of cell growth and metabolism, plays an essential role in regeneration. Lots of studies have documented the role of mTOR in regeneration. However, the mechanisms involved are still not fully elucidated. MATERIALS AND RESULTS This study aimed to explore the role and mechanism of mTOR in the regeneration of larval zebrafish tail fins. Initially, the spatial and temporal expression of mTOR signaling in the larval fin was examined, revealing its activation following tail fin amputation. Subsequently, a mTOR knockout (mTOR-KO) zebrafish line was created using CRISPR/Cas9 gene editing technology. The investigation demonstrated that mTOR depletion diminished the proliferative capacity of epithelial and mesenchymal cells during fin regeneration, with no discernible impact on cell apoptosis. Insight from SMART-seq analysis uncovered alterations in the cell cycle, mitochondrial functions and metabolic pathways when mTOR signaling was suppressed during fin regeneration. Furthermore, mTOR was confirmed to enhance mitochondrial functions and Ca2 + activation following fin amputation. These findings suggest a potential role for mTOR in promoting mitochondrial fission to facilitate tail fin regeneration. CONCLUSION In summary, our results demonstrated that mTOR played a key role in larval zebrafish tail fin regeneration, via promoting mitochondrial fission and proliferation of blastema cells.
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Affiliation(s)
- Gongyi Xiao
- Center for Joint Surgery, Department of Orthopedic Surgery, The Second Affiliated Hospital of Chongqing Medical University, 74 Linjiang Road, Chongqing, 400010, China
| | - Xiangwei Li
- Center for Joint Surgery, Department of Orthopedic Surgery, The Second Affiliated Hospital of Chongqing Medical University, 74 Linjiang Road, Chongqing, 400010, China
| | - Huiping Yang
- Department of Cardiology, The Second Affiliated Hospital of Chongqing Medical University, 74 Linjiang Road, Chongqing, 400010, China
| | - Ruobin Zhang
- Department of Wound Repair and Rehabilitation Medicine, State Key Laboratory of Trauma, Burns and Combined Injury, Trauma Center, Research Institute of Surgery, Daping Hospital, Army Medical University, Chongqing, 400042, China
| | - Junlan Huang
- Department of Wound Repair and Rehabilitation Medicine, State Key Laboratory of Trauma, Burns and Combined Injury, Trauma Center, Research Institute of Surgery, Daping Hospital, Army Medical University, Chongqing, 400042, China
| | - Yu Tian
- Department of Wound Repair and Rehabilitation Medicine, State Key Laboratory of Trauma, Burns and Combined Injury, Trauma Center, Research Institute of Surgery, Daping Hospital, Army Medical University, Chongqing, 400042, China
- Ministry of Education College of Bioengineering, Chongqing University, Chongqing, 400044, P. R. China
| | - Mao Nie
- Center for Joint Surgery, Department of Orthopedic Surgery, The Second Affiliated Hospital of Chongqing Medical University, 74 Linjiang Road, Chongqing, 400010, China.
| | - Xianding Sun
- Center for Joint Surgery, Department of Orthopedic Surgery, The Second Affiliated Hospital of Chongqing Medical University, 74 Linjiang Road, Chongqing, 400010, China.
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Romagnolo A, Dematteis G, Scheper M, Luinenburg MJ, Mühlebner A, Van Hecke W, Manfredi M, De Giorgis V, Reano S, Filigheddu N, Bortolotto V, Tapella L, Anink JJ, François L, Dedeurwaerdere S, Mills JD, Genazzani AA, Lim D, Aronica E. Astroglial calcium signaling and homeostasis in tuberous sclerosis complex. Acta Neuropathol 2024; 147:48. [PMID: 38418708 PMCID: PMC10901927 DOI: 10.1007/s00401-024-02711-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Revised: 02/12/2024] [Accepted: 02/20/2024] [Indexed: 03/02/2024]
Abstract
Tuberous Sclerosis Complex (TSC) is a multisystem genetic disorder characterized by the development of benign tumors in various organs, including the brain, and is often accompanied by epilepsy, neurodevelopmental comorbidities including intellectual disability and autism. A key hallmark of TSC is the hyperactivation of the mechanistic target of rapamycin (mTOR) signaling pathway, which induces alterations in cortical development and metabolic processes in astrocytes, among other cellular functions. These changes could modulate seizure susceptibility, contributing to the progression of epilepsy and its associated comorbidities. Epilepsy is characterized by dysregulation of calcium (Ca2+) channels and intracellular Ca2+ dynamics. These factors contribute to hyperexcitability, disrupted synaptogenesis, and altered synchronization of neuronal networks, all of which contribute to seizure activity. This study investigates the intricate interplay between altered Ca2+ dynamics, mTOR pathway dysregulation, and cellular metabolism in astrocytes. The transcriptional profile of TSC patients revealed significant alterations in pathways associated with cellular respiration, ER and mitochondria, and Ca2+ regulation. TSC astrocytes exhibited lack of responsiveness to various stimuli, compromised oxygen consumption rate and reserve respiratory capacity underscoring their reduced capacity to react to environmental changes or cellular stress. Furthermore, our study revealed significant reduction of store operated calcium entry (SOCE) along with strong decrease of basal mitochondrial Ca2+ concentration and Ca2+ influx in TSC astrocytes. In addition, we observed alteration in mitochondrial membrane potential, characterized by increased depolarization in TSC astrocytes. Lastly, we provide initial evidence of structural abnormalities in mitochondria within TSC patient-derived astrocytes, suggesting a potential link between disrupted Ca2+ signaling and mitochondrial dysfunction. Our findings underscore the complexity of the relationship between Ca2+ signaling, mitochondria dynamics, apoptosis, and mTOR hyperactivation. Further exploration is required to shed light on the pathophysiology of TSC and on TSC associated neuropsychiatric disorders offering further potential avenues for therapeutic development.
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Affiliation(s)
- Alessia Romagnolo
- Department of (Neuro) Pathology, Amsterdam UMC, University of Amsterdam, Amsterdam Neuroscience, Amsterdam, The Netherlands.
| | - Giulia Dematteis
- Department of Pharmaceutical Sciences, Università del Piemonte Orientale "Amedeo Avogadro", Novara, Italy
| | - Mirte Scheper
- Department of (Neuro) Pathology, Amsterdam UMC, University of Amsterdam, Amsterdam Neuroscience, Amsterdam, The Netherlands
| | - Mark J Luinenburg
- Department of (Neuro) Pathology, Amsterdam UMC, University of Amsterdam, Amsterdam Neuroscience, Amsterdam, The Netherlands
| | - Angelika Mühlebner
- Department of (Neuro) Pathology, Amsterdam UMC, University of Amsterdam, Amsterdam Neuroscience, Amsterdam, The Netherlands
- Department of Pathology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Wim Van Hecke
- Department of Pathology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Marcello Manfredi
- Center on Autoimmune and Allergic Diseases (CAAD), UPO, Novara, Italy
- Department of Translational Medicine, UPO, Novara, Italy
| | - Veronica De Giorgis
- Center on Autoimmune and Allergic Diseases (CAAD), UPO, Novara, Italy
- Department of Translational Medicine, UPO, Novara, Italy
| | - Simone Reano
- Center on Autoimmune and Allergic Diseases (CAAD), UPO, Novara, Italy
| | | | - Valeria Bortolotto
- Department of Pharmaceutical Sciences, Università del Piemonte Orientale "Amedeo Avogadro", Novara, Italy
| | - Laura Tapella
- Department of Pharmaceutical Sciences, Università del Piemonte Orientale "Amedeo Avogadro", Novara, Italy
| | - Jasper J Anink
- Department of (Neuro) Pathology, Amsterdam UMC, University of Amsterdam, Amsterdam Neuroscience, Amsterdam, The Netherlands
| | - Liesbeth François
- Neurosciences Therapeutic Area, UCB Pharma, Braine-L'Alleud, Belgium
| | | | - James D Mills
- Department of (Neuro) Pathology, Amsterdam UMC, University of Amsterdam, Amsterdam Neuroscience, Amsterdam, The Netherlands
- Department of Clinical and Experimental Epilepsy, UCL, London, UK
- Chalfont Centre for Epilepsy, Chalfont St Peter, UK
| | - Armando A Genazzani
- Department of Pharmaceutical Sciences, Università del Piemonte Orientale "Amedeo Avogadro", Novara, Italy
| | - Dmitry Lim
- Department of Pharmaceutical Sciences, Università del Piemonte Orientale "Amedeo Avogadro", Novara, Italy
| | - Eleonora Aronica
- Department of (Neuro) Pathology, Amsterdam UMC, University of Amsterdam, Amsterdam Neuroscience, Amsterdam, The Netherlands
- Stichting Epilepsie Instellingen Nederland (SEIN), Heemstede, The Netherlands
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Nguyen HT, Wiederkehr A, Wollheim CB, Park KS. Regulation of autophagy by perilysosomal calcium: a new player in β-cell lipotoxicity. Exp Mol Med 2024; 56:273-288. [PMID: 38297165 PMCID: PMC10907728 DOI: 10.1038/s12276-024-01161-x] [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: 05/03/2023] [Revised: 10/16/2023] [Accepted: 11/09/2023] [Indexed: 02/02/2024] Open
Abstract
Autophagy is an essential quality control mechanism for maintaining organellar functions in eukaryotic cells. Defective autophagy in pancreatic beta cells has been shown to be involved in the progression of diabetes through impaired insulin secretion under glucolipotoxic stress. The underlying mechanism reveals the pathologic role of the hyperactivation of mechanistic target of rapamycin (mTOR), which inhibits lysosomal biogenesis and autophagic processes. Moreover, accumulating evidence suggests that oxidative stress induces Ca2+ depletion in the endoplasmic reticulum (ER) and cytosolic Ca2+ overload, which may contribute to mTOR activation in perilysosomal microdomains, leading to autophagic defects and β-cell failure due to lipotoxicity. This review delineates the antagonistic regulation of autophagic flux by mTOR and AMP-dependent protein kinase (AMPK) at the lysosomal membrane, and both of these molecules could be activated by perilysosomal calcium signaling. However, aberrant and persistent Ca2+ elevation upon lipotoxic stress increases mTOR activity and suppresses autophagy. Therefore, normalization of autophagy is an attractive therapeutic strategy for patients with β-cell failure and diabetes.
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Affiliation(s)
- Ha Thu Nguyen
- Department of Physiology, Yonsei University Wonju College of Medicine, Wonju, Korea
- Mitohormesis Research Center, Yonsei University Wonju College of Medicine, Wonju, Korea
| | | | - Claes B Wollheim
- Department of Cell Physiology and Metabolism, University of Geneva, Geneva, Switzerland.
- Department of Clinical Sciences, Lund University, Malmö, Sweden.
| | - Kyu-Sang Park
- Department of Physiology, Yonsei University Wonju College of Medicine, Wonju, Korea.
- Mitohormesis Research Center, Yonsei University Wonju College of Medicine, Wonju, Korea.
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Huang J, Li J, Ning Y, Ren Y, Shao Y, Zhang H, Zong X, Shi H. Enhancement of PPARα-Inhibited Leucine Metabolism-Stimulated β-Casein Synthesis and Fatty Acid Synthesis in Primary Bovine Mammary Epithelial Cells. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2023; 71:16184-16193. [PMID: 37853551 DOI: 10.1021/acs.jafc.3c00712] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2023]
Abstract
Leucine, a kind of branched-chain amino acid, plays a regulatory role in the milk production of mammalian mammary glands, but its regulatory functions and underlying molecular mechanisms remain unknown. This work showed that a leucine-enriched mixture (LEUem) supplementation increased the levels of milk protein and milk fat synthesis in primary bovine mammary epithelial cells (BMECs). RNA-seq of leucine-treated BMECs indicated alterations in lipid metabolism, translation, ribosomal structure and biogenesis, and inflammatory response signaling pathways. Meanwhile, the supplementation of leucine resulted in mTOR activation and increased the expression of BCKDHA, FASN, ACC, and SCD1. Interestingly, the expression of PPARα was independently correlated with the leucine-supplemented dose. PPARα activated by WY-14643 caused significant suppression of lipogenic genes expression. Furthermore, WY-14643 attenuated leucine-induced β-casein synthesis and enhanced the level of BCKDHA expression. Moreover, promoter analysis revealed a peroxisome-proliferator-response element (PPRE) site in the bovine BCKDHA promoter, and WY-14643 promoted the recruitment of PPARα onto the BCKDHA promoter. Together, the present data indicate that leucine promotes the synthesis of β-casein and fatty acid and that PPARα-involved leucine catabolism is the key target.
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Affiliation(s)
- Jiangtao Huang
- Shaanxi Key Laboratory of Molecular Biology for Agriculture, College of Animal Science and Technology, Northwest A&F University, Yangling 712100, China
| | - Jintao Li
- Shaanxi Key Laboratory of Molecular Biology for Agriculture, College of Animal Science and Technology, Northwest A&F University, Yangling 712100, China
| | - Yong Ning
- Shaanxi Key Laboratory of Molecular Biology for Agriculture, College of Animal Science and Technology, Northwest A&F University, Yangling 712100, China
| | - Yalun Ren
- Shaanxi Key Laboratory of Molecular Biology for Agriculture, College of Animal Science and Technology, Northwest A&F University, Yangling 712100, China
| | - Yuexin Shao
- Shaanxi Key Laboratory of Molecular Biology for Agriculture, College of Animal Science and Technology, Northwest A&F University, Yangling 712100, China
| | - Huawen Zhang
- Shaanxi Key Laboratory of Molecular Biology for Agriculture, College of Animal Science and Technology, Northwest A&F University, Yangling 712100, China
| | - Xueyang Zong
- Shaanxi Key Laboratory of Molecular Biology for Agriculture, College of Animal Science and Technology, Northwest A&F University, Yangling 712100, China
| | - Huaiping Shi
- Shaanxi Key Laboratory of Molecular Biology for Agriculture, College of Animal Science and Technology, Northwest A&F University, Yangling 712100, China
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New Insights into the Regulation of mTOR Signaling via Ca 2+-Binding Proteins. Int J Mol Sci 2023; 24:ijms24043923. [PMID: 36835331 PMCID: PMC9959742 DOI: 10.3390/ijms24043923] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 02/09/2023] [Accepted: 02/13/2023] [Indexed: 02/17/2023] Open
Abstract
Environmental factors are important regulators of cell growth and proliferation. Mechanistic target of rapamycin (mTOR) is a central kinase that maintains cellular homeostasis in response to a variety of extracellular and intracellular inputs. Dysregulation of mTOR signaling is associated with many diseases, including diabetes and cancer. Calcium ion (Ca2+) is important as a second messenger in various biological processes, and its intracellular concentration is tightly regulated. Although the involvement of Ca2+ mobilization in mTOR signaling has been reported, the detailed molecular mechanisms by which mTOR signaling is regulated are not fully understood. The link between Ca2+ homeostasis and mTOR activation in pathological hypertrophy has heightened the importance in understanding Ca2+-regulated mTOR signaling as a key mechanism of mTOR regulation. In this review, we introduce recent findings on the molecular mechanisms of regulation of mTOR signaling by Ca2+-binding proteins, particularly calmodulin (CaM).
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Kazami M, Sakamoto T, Suzuki T, Inoue H, Kato H, Kobayashi KI, Tadokoro T, Yamamoto Y. Ca2+/Calmodulin induces translocation of membrane-associated TSC2 to the nucleus where it suppresses CYP24A1 expression. Biosci Biotechnol Biochem 2022; 87:45-53. [PMID: 36331254 DOI: 10.1093/bbb/zbac174] [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: 07/11/2022] [Accepted: 10/31/2022] [Indexed: 11/06/2022]
Abstract
Tuberous sclerosis complex 2 (TSC2) is a tumor-suppressor protein. A loss of TSC2 function induces hyperactivation of mechanistic target of rapamycin (mTOR). The C-terminal region of TSC2 contains a calmodulin (CaM) binding region and the CaM-TSC2 interaction contributes to proper mTOR activity. However, other downstream signaling pathways/effectors activated by the CaM-TSC2 complex have not been fully elucidated. In this study, we found that activation of Ca2+/CaM signaling resulted in the translocation of membrane-associated TSC2 to the nucleus and suppressed the transcriptional activity of the vitamin D receptor (VDR). TSC2 was released from the membrane in an activated CaM-dependent state in rat brain and HeLa cells. It subsequently formed a transcriptional complex to partially suppress the transcription of CYP24A1, a well-known VDR target gene. These data suggest, in part, that TSC2 attenuates VDR-associated transcriptional regulation via Ca2+/CaM signaling.
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Affiliation(s)
- Machiko Kazami
- Department of Agricultural Chemistry, Faculty of Applied Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya-ku, Tokyo, Japan
| | - Tomoya Sakamoto
- Department of Agricultural Chemistry, Faculty of Applied Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya-ku, Tokyo, Japan
| | - Tsukasa Suzuki
- Department of Agricultural Chemistry, Faculty of Applied Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya-ku, Tokyo, Japan
| | - Hirofumi Inoue
- Department of Agricultural Chemistry, Faculty of Applied Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya-ku, Tokyo, Japan
| | - Hayato Kato
- Department of Agricultural Chemistry, Faculty of Applied Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya-ku, Tokyo, Japan
| | - Ken-Ichi Kobayashi
- Department of Agricultural Chemistry, Faculty of Applied Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya-ku, Tokyo, Japan
| | - Tadahiro Tadokoro
- Department of Agricultural Chemistry, Faculty of Applied Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya-ku, Tokyo, Japan
| | - Yuji Yamamoto
- Department of Agricultural Chemistry, Faculty of Applied Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya-ku, Tokyo, Japan
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Renal Transcriptome and Metabolome in Mice with Principal Cell-Specific Ablation of the Tsc1 Gene: Derangements in Pathways Associated with Cell Metabolism, Growth and Acid Secretion. Int J Mol Sci 2022; 23:ijms231810601. [PMID: 36142537 PMCID: PMC9502912 DOI: 10.3390/ijms231810601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Revised: 09/02/2022] [Accepted: 09/06/2022] [Indexed: 11/17/2022] Open
Abstract
Tuberous sclerosis complex (TSC) is caused by mutations in the hamartin (TSC1) or tuberin (TSC2) genes. Using a mouse model of TSC renal cystogenesis that we have previously described, the current studies delineate the metabolic changes in the kidney and their relation to alterations in renal gene expression. To accomplish this, we compared the metabolome and transcriptome of kidneys from 28-day-old wildtype (Wt) and principal cell-specific Tsc1 KO (Tsc1 KO) mice using targeted 1H nuclear magnetic resonance targeted metabolomic and RNA-seq analyses. The significant changes in the kidney metabolome of Tsc1 KO mice included reductions in the level of several amino acids and significant decreases in creatine, NADH, inosine, UDP-galactose, GTP and myo-inositol levels. These derangements may affect energy production and storage, signal transduction and synthetic pathways. The pertinent derangement in the transcriptome of Tsc1 KO mice was associated with increased collecting duct acid secretion, active cell division and the up-regulation of signaling pathways (e.g., MAPK and AKT/PI3K) that suppress the TSC2 GTPase-activating function. The combined renal metabolome and transcriptome alterations observed in these studies correlate with the unregulated growth and predominance of genotypically normal A-intercalated cells in the epithelium of renal cysts in Tsc1 KO mice.
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Ion Channels and Pumps in Autophagy: A Reciprocal Relationship. Cells 2021; 10:cells10123537. [PMID: 34944044 PMCID: PMC8700256 DOI: 10.3390/cells10123537] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 12/07/2021] [Accepted: 12/08/2021] [Indexed: 12/24/2022] Open
Abstract
Autophagy, the process of cellular self-degradation, is intrinsically tied to the degradative function of the lysosome. Several diseases have been linked to lysosomal degradative defects, including rare lysosomal storage disorders and neurodegenerative diseases. Ion channels and pumps play a major regulatory role in autophagy. Importantly, calcium signaling produced by TRPML1 (transient receptor potential cation channel, mucolipin subfamily) has been shown to regulate autophagic progression through biogenesis of autophagic-lysosomal organelles, activation of mTORC1 (mechanistic target of rapamycin complex 1) and degradation of autophagic cargo. ER calcium channels such as IP3Rs supply calcium for the lysosome, and lysosomal function is severely disrupted in the absence of lysosomal calcium replenishment by the ER. TRPML1 function is also regulated by LC3 (microtubule-associated protein light chain 3) and mTORC1, two critical components of the autophagic network. Here we provide an overview of the current knowledge about ion channels and pumps-including lysosomal V-ATPase (vacuolar proton-ATPase), which is required for acidification and hence proper enzymatic activity of lysosomal hydrolases-in the regulation of autophagy, and discuss how functional impairment of some of these leads to diseases.
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