51
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Lee DD, Hochstetler A, Sah E, Xu H, Lowe CW, Santiaguel S, Thornton JL, Pajakowski A, Schwarz MA. Influence of aminoacyl-tRNA synthetase complex-interacting multifunctional protein 1 on epithelial differentiation and organization during lung development. Am J Physiol Lung Cell Mol Physiol 2020; 319:L369-L379. [PMID: 32579851 DOI: 10.1152/ajplung.00518.2019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Proper development of the respiratory bronchiole and alveolar epithelium proceeds through coordinated cross talk between the interface of epithelium and neighboring mesenchyme. Signals that facilitate and coordinate the cross talk as the bronchial forming canalicular stage transitions to construction of air-exchanging capillary-alveoli niche in the alveolar stage are poorly understood. Expressed within this decisive region, levels of aminoacyl-tRNA synthetase complex-interacting multifunctional protein 1 (AIMP1) inversely correlate with the maturation of the lung. The present study addresses the role of AIMP1 in lung development through the generation and characterization of Aimp1-/- mutant mice. Mating of Aimp1+/- produced offspring in expected Mendelian ratios throughout embryonic development. However, newborn Aimp1-/- pups exhibited neonatal lethality with mild cyanosis. Imaging both structure and ultrastructure of Aimp1-/- lungs showed disorganized bronchial epithelium, decreased type I but not type II cell differentiation, increased distal vessels, and disruption of E-cadherin deposition in cell-cell junctions. Supporting the in vivo findings of disrupted epithelial cell-cell junctions, in vitro biochemical experiments show that a portion of AIMP1 binds to phosphoinositides, the lipid anchor of proteins that have a fundamental role in both cellular membrane and actin cytoskeleton organization; a dramatic disruption in F-actin cytoskeleton was observed in Aimp1-/- mouse embryonic fibroblasts. Such observed structural defects may lead to disrupted cell-cell boundaries. Together, these results suggest a requirement of AIMP1 in epithelial cell differentiation in proper lung development.
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Affiliation(s)
- Daniel D Lee
- Department of Anatomy, Cell Biology and Physiology, Indiana University School of Medicine, South Bend, Indiana.,Department of Pediatrics, Indiana University School of Medicine, South Bend, Indiana
| | - Alexandra Hochstetler
- Department of Anatomy, Cell Biology and Physiology, Indiana University School of Medicine, South Bend, Indiana.,Department of Pediatrics, Indiana University School of Medicine, South Bend, Indiana
| | - Eric Sah
- Department of Applied and Computational Mathematics and Statistics, University of Notre Dame, South Bend, Indiana
| | - Haiming Xu
- Department of Pediatrics, University of Texas-Southwestern, Dallas, Texas
| | - Chinn-Woan Lowe
- Department of Anatomy, Cell Biology and Physiology, Indiana University School of Medicine, South Bend, Indiana.,Department of Pediatrics, Indiana University School of Medicine, South Bend, Indiana
| | - Sara Santiaguel
- Department of Anatomy, Cell Biology and Physiology, Indiana University School of Medicine, South Bend, Indiana.,Department of Pediatrics, Indiana University School of Medicine, South Bend, Indiana
| | - Janet Lea Thornton
- Department of Pediatrics, University of Texas-Southwestern, Dallas, Texas
| | - Adam Pajakowski
- Department of Anatomy, Cell Biology and Physiology, Indiana University School of Medicine, South Bend, Indiana.,Department of Pediatrics, Indiana University School of Medicine, South Bend, Indiana
| | - Margaret A Schwarz
- Department of Anatomy, Cell Biology and Physiology, Indiana University School of Medicine, South Bend, Indiana.,Department of Pediatrics, Indiana University School of Medicine, South Bend, Indiana.,Department of Biological Sciences, University of Notre Dame, South Bend, Indiana.,Department of Pediatrics, University of Texas-Southwestern, Dallas, Texas
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52
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Gong L, Wang S, Shen L, Liu C, Shenouda M, Li B, Liu X, Shaw JA, Wineman AL, Yang Y, Xiong D, Eichmann A, Evans SM, Weiss SJ, Si MS. SLIT3 deficiency attenuates pressure overload-induced cardiac fibrosis and remodeling. JCI Insight 2020; 5:136852. [PMID: 32644051 PMCID: PMC7406261 DOI: 10.1172/jci.insight.136852] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Accepted: 05/06/2020] [Indexed: 01/28/2023] Open
Abstract
In pulmonary hypertension and certain forms of congenital heart disease, ventricular pressure overload manifests at birth and is an obligate hemodynamic abnormality that stimulates myocardial fibrosis, which leads to ventricular dysfunction and poor clinical outcomes. Thus, an attractive strategy is to attenuate the myocardial fibrosis to help preserve ventricular function. Here, by analyzing RNA-sequencing databases and comparing the transcript and protein levels of fibrillar collagen in WT and global-knockout mice, we found that slit guidance ligand 3 (SLIT3) was present predominantly in fibrillar collagen-producing cells and that SLIT3 deficiency attenuated collagen production in the heart and other nonneuronal tissues. We then performed transverse aortic constriction or pulmonary artery banding to induce left and right ventricular pressure overload, respectively, in WT and knockout mice. We discovered that SLIT3 deficiency abrogated fibrotic and hypertrophic changes and promoted long-term ventricular function and overall survival in both left and right ventricular pressure overload. Furthermore, we found that SLIT3 stimulated fibroblast activity and fibrillar collagen production, which coincided with the transcription and nuclear localization of the mechanotransducer yes-associated protein 1. These results indicate that SLIT3 is important for regulating fibroblast activity and fibrillar collagen synthesis in an autocrine manner, making it a potential therapeutic target for fibrotic diseases, especially myocardial fibrosis and adverse remodeling induced by persistent afterload elevation.
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Affiliation(s)
- Lianghui Gong
- Section of Pediatric Cardiovascular Surgery, Department of Cardiac Surgery, Michigan Medicine, University of Michigan, Ann Arbor, Michigan, USA.,Department of Cardiovascular Surgery, The Second Xiangya Hospital of Central South University, Changsha, China
| | - Shuyun Wang
- Section of Pediatric Cardiovascular Surgery, Department of Cardiac Surgery, Michigan Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Li Shen
- Section of Pediatric Cardiovascular Surgery, Department of Cardiac Surgery, Michigan Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Catherine Liu
- Section of Pediatric Cardiovascular Surgery, Department of Cardiac Surgery, Michigan Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Mena Shenouda
- Section of Pediatric Cardiovascular Surgery, Department of Cardiac Surgery, Michigan Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Baolei Li
- Section of Pediatric Cardiovascular Surgery, Department of Cardiac Surgery, Michigan Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Xiaoxiao Liu
- Section of Pediatric Cardiovascular Surgery, Department of Cardiac Surgery, Michigan Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | | | - Alan L. Wineman
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan, USA
| | - Yifeng Yang
- Department of Cardiovascular Surgery, The Second Xiangya Hospital of Central South University, Changsha, China
| | - Dingding Xiong
- Section of Pediatric Cardiovascular Surgery, Department of Cardiac Surgery, Michigan Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Anne Eichmann
- Yale Cardiovascular Research Center, Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, USA.,Paris Cardiovascular Research Center, INSERM U970, Paris, France.,Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Sylvia M. Evans
- Skaggs School of Pharmacy and Pharmaceutical Sciences,,Department of Medicine, and,Department of Pharmacology, UCSD, La Jolla, California, USA
| | - Stephen J. Weiss
- Division of Genetic Medicine,,Department of Internal Medicine,,Life Sciences Institute,,Cellular and Molecular Biology Graduate Program, and,Rogel Cancer Center, Michigan Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Ming-Sing Si
- Section of Pediatric Cardiovascular Surgery, Department of Cardiac Surgery, Michigan Medicine, University of Michigan, Ann Arbor, Michigan, USA
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53
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Qin Y, Ting F, Kim MJ, Strelnikov J, Harmon J, Gao F, Dose A, Teng BB, Alipour MA, Yao Z, Crooke R, Krauss RM, Medina MW. Phosphatidylinositol-(4,5)-Bisphosphate Regulates Plasma Cholesterol Through LDL (Low-Density Lipoprotein) Receptor Lysosomal Degradation. Arterioscler Thromb Vasc Biol 2020; 40:1311-1324. [PMID: 32188273 DOI: 10.1161/atvbaha.120.314033] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE TMEM55B (transmembrane protein 55B) is a phosphatidylinositol-(4,5)-bisphosphate (PI[4,5]P2) phosphatase that regulates cellular cholesterol, modulates LDLR (low-density lipoprotein receptor) decay, and lysosome function. We tested the effects of Tmem55b knockdown on plasma lipids in mice and assessed the roles of LDLR lysosomal degradation and change in (PI[4,5]P2) in mediating these effects. Approach and Results: Western diet-fed C57BL/6J mice were treated with antisense oligonucleotides against Tmem55b or a nontargeting control for 3 to 4 weeks. Hepatic Tmem55b transcript and protein levels were reduced by ≈70%, and plasma non-HDL (high-density lipoprotein) cholesterol was increased ≈1.8-fold (P<0.0001). Immunoblot analysis of fast protein liquid chromatography (FPLC) fractions revealed enrichment of ApoE-containing particles in the LDL size range. In contrast, Tmem55b knockdown had no effect on plasma cholesterol in Ldlr-/- mice. In primary hepatocytes and liver tissues from Tmem55b knockdown mice, there was decreased LDLR protein. In the hepatocytes, there was increased lysosome staining and increased LDLR-lysosome colocalization. Impairment of lysosome function (incubation with NH4Cl or knockdown of the lysosomal proteins LAMP1 or RAB7) abolished the effect of TMEM55B knockdown on LDLR in HepG2 (human hepatoma) cells. Colocalization of the recycling endosome marker RAB11 (Ras-related protein 11) with LDLR in HepG2 cells was reduced by 50% upon TMEM55B knockdown. Finally, knockdown increased hepatic PI(4,5)P2 levels in vivo and in HepG2 cells, while TMEM55B overexpression in vitro decreased PI(4,5)P2. TMEM55B knockdown decreased, whereas overexpression increased, LDL uptake in HepG2 cells. Notably, the TMEM55B overexpression effect was reversed by incubation with PI(4,5)P2. Conclusions: These findings indicate a role for TMEM55B in regulating plasma cholesterol levels by affecting PI(4,5)P2-mediated LDLR lysosomal degradation.
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Affiliation(s)
- Yuanyuan Qin
- From the Department of Pediatrics, University of California San Francisco, Oakland (Y.Q., F.T., R.M.K., M.W.M.)
| | - Flora Ting
- From the Department of Pediatrics, University of California San Francisco, Oakland (Y.Q., F.T., R.M.K., M.W.M.)
| | - Mee J Kim
- Children's Hospital Oakland Research Institute, CA (M.J.K., J.S., J.H., F.G., A.D.)
| | - Jacob Strelnikov
- Children's Hospital Oakland Research Institute, CA (M.J.K., J.S., J.H., F.G., A.D.)
| | - Joseph Harmon
- Children's Hospital Oakland Research Institute, CA (M.J.K., J.S., J.H., F.G., A.D.)
| | - Feng Gao
- Children's Hospital Oakland Research Institute, CA (M.J.K., J.S., J.H., F.G., A.D.)
| | - Andrea Dose
- Children's Hospital Oakland Research Institute, CA (M.J.K., J.S., J.H., F.G., A.D.)
| | - Ba-Bie Teng
- Center for Human Genetics, University of Texas Health Science Center, Houston (B.-B.T.)
| | - Mohsen Amir Alipour
- Department of Biochemistry, Microbiology and Immunology, Ottawa Institute of Systems Biology, University of Ottawa, Ontario, Canada (M.A.A., Z.Y.)
| | - Zemin Yao
- Department of Biochemistry, Microbiology and Immunology, Ottawa Institute of Systems Biology, University of Ottawa, Ontario, Canada (M.A.A., Z.Y.)
| | | | - Ronald M Krauss
- From the Department of Pediatrics, University of California San Francisco, Oakland (Y.Q., F.T., R.M.K., M.W.M.)
| | - Marisa W Medina
- From the Department of Pediatrics, University of California San Francisco, Oakland (Y.Q., F.T., R.M.K., M.W.M.)
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54
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Darios F, Stevanin G. Impairment of Lysosome Function and Autophagy in Rare Neurodegenerative Diseases. J Mol Biol 2020; 432:2714-2734. [PMID: 32145221 PMCID: PMC7232018 DOI: 10.1016/j.jmb.2020.02.033] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 02/28/2020] [Accepted: 02/28/2020] [Indexed: 02/07/2023]
Abstract
Rare genetic diseases affect a limited number of patients, but their etiology is often known, facilitating the development of reliable animal models and giving the opportunity to investigate physiopathology. Lysosomal storage disorders are a group of rare diseases due to primary alteration of lysosome function. These diseases are often associated with neurological symptoms, which highlighted the importance of lysosome in neurodegeneration. Likewise, other groups of rare neurodegenerative diseases also present lysosomal alteration. Lysosomes fuse with autophagosomes and endosomes to allow the degradation of their content thanks to hydrolytic enzymes. It has emerged that alteration of the autophagy–lysosome pathway could play a critical role in neuronal death in many neurodegenerative diseases. Using a repertoire of selected rare neurodegenerative diseases, we highlight that a variety of alterations of the autophagy–lysosome pathway are associated with neuronal death. Yet, in most cases, it is still unclear why alteration of this pathway can lead to neurodegeneration. Lysosome function is impaired in many rare neurodegenerative diseases, making it a convergent point for these diseases. Impaired lysosome function is associated with alteration of the autophagy pathway. Autophagy–lysosome pathway can be impaired at various steps in different rare neurodegenerative diseases. The mechanisms linking impaired autophagy–lysosome pathway to neurodegeneration are still not fully elucidated.
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Affiliation(s)
- Frédéric Darios
- Sorbonne Université, F-75013, Paris, France; Inserm, U1127, F-75013 Paris, France; CNRS, UMR 7225, F-75013 Paris, France; Institut du Cerveau et de la Moelle Epinière, ICM, F-75013 Paris, France.
| | - Giovanni Stevanin
- Sorbonne Université, F-75013, Paris, France; Inserm, U1127, F-75013 Paris, France; CNRS, UMR 7225, F-75013 Paris, France; Institut du Cerveau et de la Moelle Epinière, ICM, F-75013 Paris, France; PSL Research University, Ecole Pratique des Hautes Etudes, Laboratoire de Neurogénétique, F-75013 Paris, France
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55
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Jung J, Venkatachalam K. TRPML1 and RAS-driven cancers - exploring a link with great therapeutic potential. Channels (Austin) 2019; 13:374-381. [PMID: 31526156 PMCID: PMC6768051 DOI: 10.1080/19336950.2019.1666457] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Revised: 09/04/2019] [Accepted: 09/08/2019] [Indexed: 12/05/2022] Open
Abstract
Activating mutations in the RAS family of proto-oncogenes represent some of the leading causes of cancer. Unmitigated proliferation of cells harboring oncogenic RAS mutations is accompanied by a massive increase in cellular bioenergetic demands, which offers unique opportunities for therapeutic intervention. To withstand the steep requirements for metabolic intermediates, RAS-driven cancer cells enhance endolysosome and autophagosome biogenesis. By degrading cellular macromolecules into metabolites that can be used by biosynthetic pathways, endolysosomes permit continued proliferation and survival in otherwise detrimental conditions. We recently showed that human cancers with activating mutations in HRAS elevate the expression of MCOLN1, which encodes an endolysosomal cation channel called TRPML1. Increased TRPML1 activity in HRAS-driven cancer cells is needed for the restoration of plasma membrane cholesterol that gets collaterally internalized during endocytosis. Inhibition of TRPML1 or knockdown of MCOLN1 leads to mislocalization of cholesterol from the plasma membrane to endolysosomes, loss of oncogenic HRAS from the cell surface, and attenuation of downstream signaling. Here, we discuss the implications of our findings and suggest strategies to leverage pathways that impinge upon TRPML1 as novel anti-cancer treatments.
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Affiliation(s)
- Jewon Jung
- Department of Integrative Biology and Pharmacology, McGovern Medical School at the University of Texas Health Sciences Center (UTHealth), Houston, TX, USA
| | - Kartik Venkatachalam
- Department of Integrative Biology and Pharmacology, McGovern Medical School at the University of Texas Health Sciences Center (UTHealth), Houston, TX, USA
- Graduate Program in Biochemistry and Cell Biology, MD Anderson Cancer Center and UTHealth Graduate School of Biomedical Sciences, Houston, TX, USA
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56
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Wheeler S, Sillence DJ. Niemann-Pick type C disease: cellular pathology and pharmacotherapy. J Neurochem 2019; 153:674-692. [PMID: 31608980 DOI: 10.1111/jnc.14895] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 09/10/2019] [Accepted: 09/15/2019] [Indexed: 12/22/2022]
Abstract
Niemann-Pick type C disease (NPCD) was first described in 1914 and affects approximately 1 in 150 000 live births. It is characterized clinically by diverse symptoms affecting liver, spleen, motor control, and brain; premature death invariably results. Its molecular origins were traced, as late as 1997, to a protein of late endosomes and lysosomes which was named NPC1. Mutation or absence of this protein leads to accumulation of cholesterol in these organelles. In this review, we focus on the intracellular events that drive the pathology of this disease. We first introduce endocytosis, a much-studied area of dysfunction in NPCD cells, and survey the various ways in which this process malfunctions. We briefly consider autophagy before attempting to map the more complex pathways by which lysosomal cholesterol storage leads to protein misregulation, mitochondrial dysfunction, and cell death. We then briefly introduce the metabolic pathways of sphingolipids (as these emerge as key species for treatment) and critically examine the various treatment approaches that have been attempted to date.
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Affiliation(s)
- Simon Wheeler
- School of Pharmacy, De Montfort University, The Gateway, Leicester, UK
| | - Dan J Sillence
- School of Pharmacy, De Montfort University, The Gateway, Leicester, UK
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57
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Min SH, Suzuki A, Weaver L, Guzman J, Chung Y, Jin H, Gonzalez F, Trasorras C, Zhao L, Spruce LA, Seeholzer SH, Behrens EM, Abrams CS. PIKfyve Deficiency in Myeloid Cells Impairs Lysosomal Homeostasis in Macrophages and Promotes Systemic Inflammation in Mice. Mol Cell Biol 2019; 39:e00158-19. [PMID: 31427458 PMCID: PMC6791654 DOI: 10.1128/mcb.00158-19] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 04/29/2019] [Accepted: 08/12/2019] [Indexed: 01/15/2023] Open
Abstract
Macrophages are professional phagocytes that are essential for host defense and tissue homeostasis. Proper membrane trafficking and degradative functions of the endolysosomal system are known to be critical for the function of these cells. We have found that PIKfyve, the kinase that synthesizes the endosomal phosphoinositide phosphatidylinositol-3,5-bisphosphate, is an essential regulator of lysosomal biogenesis and degradative functions in macrophages. Genetically engineered mice lacking PIKfyve in their myeloid cells (PIKfyvefl/fl LysM-Cre) develop diffuse tissue infiltration of foamy macrophages, hepatosplenomegaly, and systemic inflammation. PIKfyve loss in macrophages causes enlarged endolysosomal compartments and impairs the lysosomal degradative function. Moreover, PIKfyve deficiency increases the cellular levels of lysosomal proteins. Although PIKfyve deficiency reduced the activation of mTORC1 pathway and was associated with increased cleavage of TFEB proteins, this does not translate into transcriptional activation of lysosomal genes, suggesting that PIKfyve modulates the abundance of lysosomal proteins by affecting the degradation of these proteins. Our study shows that PIKfyve modulation of lysosomal degradative activity and protein expression is essential to maintain lysosomal homeostasis in macrophages.
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Affiliation(s)
- Sang Hee Min
- Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA
- Department of Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Aae Suzuki
- Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA
| | - Lehn Weaver
- Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Jessica Guzman
- Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA
| | - Yutein Chung
- Department of Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Huiyan Jin
- Department of Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Francina Gonzalez
- Department of Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Claire Trasorras
- Department of Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Liang Zhao
- Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA
| | - Lynn A Spruce
- Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | | | - Edward M Behrens
- Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Charles S Abrams
- Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA
- Department of Pathology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA
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58
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Ghosh A, Sharma S, Shinde D, Ramya V, Raghu P. A novel mass assay to measure phosphatidylinositol-5-phosphate from cells and tissues. Biosci Rep 2019; 39:BSR20192502. [PMID: 31652444 PMCID: PMC6822513 DOI: 10.1042/bsr20192502] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Revised: 09/19/2019] [Accepted: 09/27/2019] [Indexed: 12/23/2022] Open
Abstract
Phosphatidylinositol-5-phosphate (PI5P) is a low abundance lipid proposed to have functions in cell migration, DNA damage responses, receptor trafficking and insulin signalling in metazoans. However, studies of PI5P function are limited by the lack of scalable techniques to quantify its level from cells and tissues in multicellular organisms. Currently, PI5P measurement requires the use of radionuclide labelling approaches that are not easily applicable in tissues or in vivo samples. In the present study, we describe a simple and reliable, non-radioactive mass assay to measure total PI5P levels from cells and tissues of Drosophila, a genetically tractable multicellular model. We use heavy oxygen-labelled ATP (18O-ATP) to label PI5P from tissue extracts while converting it into PI(4,5)P2 using an in vitro kinase reaction. The product of this reaction can be selectively detected and quantified with high sensitivity using a liquid chromatography-tandem mass spectrometry (LC-MS/MS) platform. Further, using this method, we capture and quantify the unique acyl chain composition of PI5P from Drosophila cells and tissues. Finally, we demonstrate the use of this technique to quantify elevations in PI5P levels, from Drosophila larval tissues and cultured cells depleted of phosphatidylinositol 5 phosphate 4-kinase (PIP4K), that metabolizes PI5P into PI(4,5)P2 thus regulating its levels. Thus, we demonstrate the potential of our method to quantify PI5P levels with high sensitivity from cells and tissues of multicellular organisms thus accelerating understanding of PI5P functions in vivo.
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Affiliation(s)
- Avishek Ghosh
- National Centre for Biological Sciences, TIFR-GKVK Campus, Bellary Road, Bangalore 560065, India
| | - Sanjeev Sharma
- National Centre for Biological Sciences, TIFR-GKVK Campus, Bellary Road, Bangalore 560065, India
| | - Dhananjay Shinde
- National Centre for Biological Sciences, TIFR-GKVK Campus, Bellary Road, Bangalore 560065, India
| | - Visvanathan Ramya
- National Centre for Biological Sciences, TIFR-GKVK Campus, Bellary Road, Bangalore 560065, India
| | - Padinjat Raghu
- National Centre for Biological Sciences, TIFR-GKVK Campus, Bellary Road, Bangalore 560065, India
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59
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Aβ modulates actin cytoskeleton via SHIP2-mediated phosphoinositide metabolism. Sci Rep 2019; 9:15557. [PMID: 31664099 PMCID: PMC6820556 DOI: 10.1038/s41598-019-51914-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Accepted: 10/02/2019] [Indexed: 12/22/2022] Open
Abstract
Emerging evidences suggest that phospholipid metabolism is altered in Alzheimer’s disease (AD), but molecular mechanisms on how this affects neurodegeneration in AD is poorly understood. SHIP2 is a phosphoinositide-metabolizing enzyme, which dephosphorylates PI(3,4,5)P3 resulting to PI(3,4)P2, and it has been recently shown that Aβ directly increases the activity of SHIP2. Here we monitored, utilizing fluorescent SHIP2 biosensor, real-time increase of PI(3,4)P2-containing vesicles in HT22 cells treated with Aβ. Interestingly, PI(3,4)P2 is accumulated at late endosomes and lysosomal vesicles. We further discovered that ARAP3 can be attracted to PI(3,4)P2-positive mature endosomes via its PH domain and this facilitates the degradation of ARAP3. The reduced level of ARAP3 then causes RhoA hyperactivation and filamentous actin, which are critical for neurodegeneration in AD. These results provide a novel molecular link between Aβ and actin disruption through dysregulated phosphoinositide metabolism, and the SHIP2-PI(3,4)P2-ARAP3-RhoA signaling pathway can be considered as new therapeutic targets for synaptic dysfunctions in Alzheimer’s disease.
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60
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Ikonomov OC, Sbrissa D, Shisheva A. Small molecule PIKfyve inhibitors as cancer therapeutics: Translational promises and limitations. Toxicol Appl Pharmacol 2019; 383:114771. [PMID: 31628917 DOI: 10.1016/j.taap.2019.114771] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2019] [Revised: 09/27/2019] [Accepted: 09/29/2019] [Indexed: 11/20/2022]
Abstract
Through synthesis of two rare phosphoinositides, PtdIns(3,5)P2 and PtdIns5P, the ubiquitously expressed phosphoinositide kinase PIKfyve is implicated in pleiotropic cellular functions. Small molecules specifically inhibiting PIKfyve activity cause cytoplasmic vacuolation in all dividing cells in culture yet trigger non-apoptotic death through excessive vacuolation only in cancer cells. Intriguingly, cancer cell toxicity appears to be inhibitor-specific suggesting that additional targets beyond PIKfyve are affected. One PIKfyve inhibitor - apilimod - is already in clinical trials for treatment of B-cell malignancies. However, apilimod is inactivated in cultured cells and exhibits unexpectedly low plasma levels in patients treated with maximum oral dosage. Thus, the potential widespread use of PIKfyve inhibitors as cancer therapeutics requires progress on multiple fronts: (i) advances in methods for isolating relevant cancer cells from individual patients; (ii) delineation of the molecular mechanisms potentiating the vacuolation induced by PIKfyve inhibitors in sensitive cancer cells; (iii) design of PIKfyve inhibitors with favorable pharmacokinetics; and (iv) development of effective drug combinations.
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Affiliation(s)
- Ognian C Ikonomov
- Department of Physiology, Wayne State University School of Medicine, Detroit, MI 48201, USA.
| | - Diego Sbrissa
- Department of Urology, Wayne State University School of Medicine, Detroit, MI 48201, USA.
| | - Assia Shisheva
- Department of Physiology, Wayne State University School of Medicine, Detroit, MI 48201, USA.
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61
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Singla A, Fedoseienko A, Giridharan SSP, Overlee BL, Lopez A, Jia D, Song J, Huff-Hardy K, Weisman L, Burstein E, Billadeau DD. Endosomal PI(3)P regulation by the COMMD/CCDC22/CCDC93 (CCC) complex controls membrane protein recycling. Nat Commun 2019; 10:4271. [PMID: 31537807 PMCID: PMC6753146 DOI: 10.1038/s41467-019-12221-6] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Accepted: 08/21/2019] [Indexed: 01/04/2023] Open
Abstract
Protein recycling through the endolysosomal system relies on molecular assemblies that interact with cargo proteins, membranes, and effector molecules. Among them, the COMMD/CCDC22/CCDC93 (CCC) complex plays a critical role in recycling events. While CCC is closely associated with retriever, a cargo recognition complex, its mechanism of action remains unexplained. Herein we show that CCC and retriever are closely linked through sharing a common subunit (VPS35L), yet the integrity of CCC, but not retriever, is required to maintain normal endosomal levels of phosphatidylinositol-3-phosphate (PI(3)P). CCC complex depletion leads to elevated PI(3)P levels, enhanced recruitment and activation of WASH (an actin nucleation promoting factor), excess endosomal F-actin and trapping of internalized receptors. Mechanistically, we find that CCC regulates the phosphorylation and endosomal recruitment of the PI(3)P phosphatase MTMR2. Taken together, we show that the regulation of PI(3)P levels by the CCC complex is critical to protein recycling in the endosomal compartment. Recycling of proteins that have entered the endosome is essential to homeostasis. The COMMD/CCDC22/CCDC93 (CCC) complex is regulator of recycling but the molecular mechanisms are unclear. Here, the authors report that the CCC complex regulates endosomal recycling by maintaining PI3P levels on endosomal membranes.
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Affiliation(s)
- Amika Singla
- Department of Internal Medicine, and Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Alina Fedoseienko
- Division of Oncology Research and Department of Biochemistry and Molecular Biology, College of Medicine, Mayo Clinic, Rochester, MN, 55905, USA
| | - Sai S P Giridharan
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Brittany L Overlee
- Division of Oncology Research and Department of Biochemistry and Molecular Biology, College of Medicine, Mayo Clinic, Rochester, MN, 55905, USA
| | - Adam Lopez
- Department of Internal Medicine, and Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Da Jia
- Key Laboratory of Birth Defects and Related Diseases of Women and Children, Department of Paediatrics, Division of Neurology, West China Second University Hospital, State Key Laboratory of Biotherapy and Collaborative Innovation Center of Biotherapy, Sichuan University, Chengdu, 610041, China
| | - Jie Song
- Department of Internal Medicine, and Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Kayci Huff-Hardy
- Department of Internal Medicine, and Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Lois Weisman
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Ezra Burstein
- Department of Internal Medicine, and Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA.
| | - Daniel D Billadeau
- Division of Oncology Research and Department of Biochemistry and Molecular Biology, College of Medicine, Mayo Clinic, Rochester, MN, 55905, USA.
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62
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Raghu P, Joseph A, Krishnan H, Singh P, Saha S. Phosphoinositides: Regulators of Nervous System Function in Health and Disease. Front Mol Neurosci 2019; 12:208. [PMID: 31507376 PMCID: PMC6716428 DOI: 10.3389/fnmol.2019.00208] [Citation(s) in RCA: 69] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2019] [Accepted: 08/07/2019] [Indexed: 12/11/2022] Open
Abstract
Phosphoinositides, the seven phosphorylated derivatives of phosphatidylinositol have emerged as regulators of key sub-cellular processes such as membrane transport, cytoskeletal function and plasma membrane signaling in eukaryotic cells. All of these processes are also present in the cells that constitute the nervous system of animals and in this setting too, these are likely to tune key aspects of cell biology in relation to the unique structure and function of neurons. Phosphoinositides metabolism and function are mediated by enzymes and proteins that are conserved in evolution, and analysis of knockouts of these in animal models implicate this signaling system in neural function. Most recently, with the advent of human genome analysis, mutations in genes encoding components of the phosphoinositide signaling pathway have been implicated in human diseases although the cell biological basis of disease phenotypes in many cases remains unclear. In this review we evaluate existing evidence for the involvement of phosphoinositide signaling in human nervous system diseases and discuss ways of enhancing our understanding of the role of this pathway in the human nervous system's function in health and disease.
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Affiliation(s)
- Padinjat Raghu
- National Centre for Biological Sciences-TIFR, Bengaluru, India
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63
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Schwartz AJ, Converso-Baran K, Michele DE, Shah YM. A genetic mouse model of severe iron deficiency anemia reveals tissue-specific transcriptional stress responses and cardiac remodeling. J Biol Chem 2019; 294:14991-15002. [PMID: 31416832 DOI: 10.1074/jbc.ra119.009578] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 08/13/2019] [Indexed: 01/24/2023] Open
Abstract
Iron is a micronutrient fundamental for life. Iron homeostasis in mammals requires sustained postnatal intestinal iron absorption that maintains intracellular iron concentrations for central and systemic metabolism as well as for erythropoiesis and oxygen transport. More than 1 billion people worldwide suffer from iron deficiency anemia (IDA), a state of systemic iron insufficiency that limits the production of red blood cells and leads to tissue hypoxia and intracellular iron stress. Despite this tremendous public health concern, very few genetic models of IDA are available to study its progression. Here we developed and characterized a novel genetic mouse model of IDA. We found that tamoxifen-inducible deletion of the mammalian iron exporter ferroportin exclusively in intestinal epithelial cells leads to loss of intestinal iron absorption. Ferroportin ablation yielded a robust phenotype of progressive IDA that develops in as little as 3 months following disruption of intestinal iron absorption. We noted that, at end-stage IDA, tissue-specific transcriptional stress responses occur in which the heart shows little to no hypoxic and iron stress compared with other peripheral organs. However, morphometric and echocardiographic analysis revealed massive cardiac hypertrophy and chamber dilation, albeit with increased cardiac output at very low basal heart rates. We propose that our intestine-specific ferroportin knockout mouse model of end-stage IDA could be used in future studies to investigate IDA progression and cell-specific responses to hypoxic and iron stress.
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Affiliation(s)
- Andrew J Schwartz
- Department of Molecular & Integrative Physiology, and Internal Medicine, University of Michigan, Ann Arbor, Michigan 48109
| | - Kimber Converso-Baran
- Department of Molecular & Integrative Physiology, and Internal Medicine, University of Michigan, Ann Arbor, Michigan 48109
| | - Daniel E Michele
- Department of Molecular & Integrative Physiology, and Internal Medicine, University of Michigan, Ann Arbor, Michigan 48109.,Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, Michigan 48109
| | - Yatrik M Shah
- Department of Molecular & Integrative Physiology, and Internal Medicine, University of Michigan, Ann Arbor, Michigan 48109 .,Division of Gastroenterology, University of Michigan, Ann Arbor, Michigan 48109
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64
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Volpatti JR, Al-Maawali A, Smith L, Al-Hashim A, Brill JA, Dowling JJ. The expanding spectrum of neurological disorders of phosphoinositide metabolism. Dis Model Mech 2019; 12:12/8/dmm038174. [PMID: 31413155 PMCID: PMC6737944 DOI: 10.1242/dmm.038174] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Phosphoinositides (PIPs) are a ubiquitous group of seven low-abundance phospholipids that play a crucial role in defining localized membrane properties and that regulate myriad cellular processes, including cytoskeletal remodeling, cell signaling cascades, ion channel activity and membrane traffic. PIP homeostasis is tightly regulated by numerous inositol kinases and phosphatases, which phosphorylate and dephosphorylate distinct PIP species. The importance of these phospholipids, and of the enzymes that regulate them, is increasingly being recognized, with the identification of human neurological disorders that are caused by mutations in PIP-modulating enzymes. Genetic disorders of PIP metabolism include forms of epilepsy, neurodegenerative disease, brain malformation syndromes, peripheral neuropathy and congenital myopathy. In this Review, we provide an overview of PIP function and regulation, delineate the disorders associated with mutations in genes that modulate or utilize PIPs, and discuss what is understood about gene function and disease pathogenesis as established through animal models of these diseases. Summary: This Review highlights the intersection between phosphoinositides and the enzymes that regulate their metabolism, which together are crucial regulators of myriad cellular processes and neurological disorders.
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Affiliation(s)
- Jonathan R Volpatti
- Division of Neurology and Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Almundher Al-Maawali
- Division of Neurology and Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada.,Department of Genetics, College of Medicine and Health Sciences, Sultan Qaboos University, Muscat 123, Oman
| | - Lindsay Smith
- Division of Neurology and Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Aqeela Al-Hashim
- Division of Neurology and Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada.,Department of Neuroscience, King Fahad Medical City, Riyadh 11525, Saudi Arabia
| | - Julie A Brill
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada.,Program in Cell Biology, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
| | - James J Dowling
- Division of Neurology and Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada .,Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
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65
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Wang H, Lo WT, Haucke V. Phosphoinositide switches in endocytosis and in the endolysosomal system. Curr Opin Cell Biol 2019; 59:50-57. [DOI: 10.1016/j.ceb.2019.03.011] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Revised: 03/08/2019] [Accepted: 03/19/2019] [Indexed: 02/07/2023]
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66
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Robinson DC, Mammel AE, Logan AM, Larson AA, Schmidt EJ, Condon AF, Robinson FL. An In Vitro Model of Charcot-Marie-Tooth Disease Type 4B2 Provides Insight Into the Roles of MTMR13 and MTMR2 in Schwann Cell Myelination. ASN Neuro 2019; 10:1759091418803282. [PMID: 30419760 PMCID: PMC6236487 DOI: 10.1177/1759091418803282] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Charcot-Marie-Tooth Disorder Type 4B (CMT4B) is a demyelinating
peripheral neuropathy caused by mutations in myotubularin-related
(MTMR) proteins 2, 13, or 5 (CMT4B1/2/3), which regulate
phosphoinositide turnover and endosomal trafficking. Although mouse
models of CMT4B2 exist, an in vitro model would make
possible pharmacological and reverse genetic experiments needed to
clarify the role of MTMR13 in myelination. We have generated such a
model using Schwann cell-dorsal root ganglion (SC-DRG) explants from
Mtmr13−/− mice. Myelin sheaths
in mutant cultures contain outfoldings highly reminiscent of those
observed in the nerves of Mtmr13−/− mice
and CMT4B2 patients. Mtmr13−/− SC-DRG
explants also contain reduced Mtmr2, further supporting a role of
Mtmr13 in stabilizing Mtmr2. Elevated PI(3,5)P2 has been
implicated as a cause of myelin outfoldings in
Mtmr2−/− models. In contrast,
the role of elevated PI3P or PI(3,5)P2 in promoting
outfoldings in Mtmr13−/− models is
unclear. We found that over-expression of MTMR2 in
Mtmr13−/− SC-DRGs moderately
reduced the prevalence of myelin outfoldings. Thus, a manipulation
predicted to lower PI3P and PI(3,5)P2 partially suppressed
the phenotype caused by Mtmr13 deficiency. We also explored the
relationship between CMT4B2-like myelin outfoldings and kinases that
produce PI3P and PI(3,5)P2 by analyzing nerve pathology in
mice lacking both Mtmr13 and one of two specific PI 3-kinases.
Intriguingly, the loss of vacuolar protein sorting 34 or PI3K-C2β in
Mtmr13−/− mice had no impact
on the prevalence of myelin outfoldings. In aggregate, our findings
suggest that the MTMR13 scaffold protein likely has critical functions
other than stabilizing MTMR2 to achieve an adequate level of PI
3-phosphatase activity.
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Affiliation(s)
- Danielle C Robinson
- 1 Department of Neurology, Jungers Center for Neurosciences Research, Oregon Health & Science University, Portland, OR, USA.,2 Neuroscience Graduate Program, Oregon Health & Science University, Portland, OR, USA
| | - Anna E Mammel
- 1 Department of Neurology, Jungers Center for Neurosciences Research, Oregon Health & Science University, Portland, OR, USA.,3 Cell, Developmental & Cancer Biology Graduate Program, Oregon Health & Science University, Portland, OR, USA
| | - Anne M Logan
- 1 Department of Neurology, Jungers Center for Neurosciences Research, Oregon Health & Science University, Portland, OR, USA.,2 Neuroscience Graduate Program, Oregon Health & Science University, Portland, OR, USA
| | - Aubree A Larson
- 1 Department of Neurology, Jungers Center for Neurosciences Research, Oregon Health & Science University, Portland, OR, USA
| | - Eric J Schmidt
- 1 Department of Neurology, Jungers Center for Neurosciences Research, Oregon Health & Science University, Portland, OR, USA
| | - Alec F Condon
- 1 Department of Neurology, Jungers Center for Neurosciences Research, Oregon Health & Science University, Portland, OR, USA.,2 Neuroscience Graduate Program, Oregon Health & Science University, Portland, OR, USA
| | - Fred L Robinson
- 1 Department of Neurology, Jungers Center for Neurosciences Research, Oregon Health & Science University, Portland, OR, USA.,4 Vollum Institute, Oregon Health & Science University, Portland, OR, USA
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67
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Nakada-Tsukui K, Watanabe N, Maehama T, Nozaki T. Phosphatidylinositol Kinases and Phosphatases in Entamoeba histolytica. Front Cell Infect Microbiol 2019; 9:150. [PMID: 31245297 PMCID: PMC6563779 DOI: 10.3389/fcimb.2019.00150] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2018] [Accepted: 04/23/2019] [Indexed: 12/11/2022] Open
Abstract
Phosphatidylinositol (PtdIns) metabolism is indispensable in eukaryotes. Phosphoinositides (PIs) are phosphorylated derivatives of PtdIns and consist of seven species generated by reversible phosphorylation of the inositol moieties at the positions 3, 4, and 5. Each of the seven PIs has a unique subcellular and membrane domain distribution. In the enteric protozoan parasite Entamoeba histolytica, it has been previously shown that the PIs phosphatidylinositol 3-phosphate (PtdIns3P), PtdIns(4,5)P2, and PtdIns(3,4,5)P3 are localized to phagosomes/phagocytic cups, plasma membrane, and phagocytic cups, respectively. The localization of these PIs in E. histolytica is similar to that in mammalian cells, suggesting that PIs have orthologous functions in E. histolytica. In contrast, the conservation of the enzymes that metabolize PIs in this organism has not been well-documented. In this review, we summarized the full repertoire of the PI kinases and PI phosphatases found in E. histolytica via a genome-wide survey of the current genomic information. E. histolytica appears to have 10 PI kinases and 23 PI phosphatases. It has a panel of evolutionarily conserved enzymes that generate all the seven PI species. However, class II PI 3-kinases, type II PI 4-kinases, type III PI 5-phosphatases, and PI 4P-specific phosphatases are not present. Additionally, regulatory subunits of class I PI 3-kinases and type III PI 4-kinases have not been identified. Instead, homologs of class I PI 3-kinases and PTEN, a PI 3-phosphatase, exist as multiple isoforms, which likely reflects that elaborate signaling cascades mediated by PtdIns(3,4,5)P3 are present in this organism. There are several enzymes that have the nuclear localization signal: one phosphatidylinositol phosphate (PIP) kinase, two PI 3-phosphatases, and one PI 5-phosphatase; this suggests that PI metabolism also has conserved roles related to nuclear functions in E. histolytica, as it does in model organisms.
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Affiliation(s)
- Kumiko Nakada-Tsukui
- Department of Parasitology, National Institute of Infectious Diseases, Tokyo, Japan
| | - Natsuki Watanabe
- Department of Parasitology, National Institute of Infectious Diseases, Tokyo, Japan.,Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Japan
| | - Tomohiko Maehama
- Division of Molecular and Cellular Biology, Graduate School of Medicine, Kobe University, Kobe, Japan
| | - Tomoyoshi Nozaki
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
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68
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Fernandez-Mosquera L, Yambire KF, Couto R, Pereyra L, Pabis K, Ponsford AH, Diogo CV, Stagi M, Milosevic I, Raimundo N. Mitochondrial respiratory chain deficiency inhibits lysosomal hydrolysis. Autophagy 2019; 15:1572-1591. [PMID: 30917721 PMCID: PMC6693470 DOI: 10.1080/15548627.2019.1586256] [Citation(s) in RCA: 77] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Mitochondria are key organelles for cellular metabolism, and regulate several processes including cell death and macroautophagy/autophagy. Here, we show that mitochondrial respiratory chain (RC) deficiency deactivates AMP-activated protein kinase (AMPK, a key regulator of energy homeostasis) signaling in tissue and in cultured cells. The deactivation of AMPK in RC-deficiency is due to increased expression of the AMPK-inhibiting protein FLCN (folliculin). AMPK is found to be necessary for basal lysosomal function, and AMPK deactivation in RC-deficiency inhibits lysosomal function by decreasing the activity of the lysosomal Ca2+ channel MCOLN1 (mucolipin 1). MCOLN1 is regulated by phosphoinositide kinase PIKFYVE and its product PtdIns(3,5)P2, which is also decreased in RC-deficiency. Notably, reactivation of AMPK, in a PIKFYVE-dependent manner, or of MCOLN1 in RC-deficient cells, restores lysosomal hydrolytic capacity. Building on these data and the literature, we propose that downregulation of the AMPK-PIKFYVE-PtdIns(3,5)P2-MCOLN1 pathway causes lysosomal Ca2+ accumulation and impaired lysosomal catabolism. Besides unveiling a novel role of AMPK in lysosomal function, this study points to the mechanism that links mitochondrial malfunction to impaired lysosomal catabolism, underscoring the importance of AMPK and the complexity of organelle cross-talk in the regulation of cellular homeostasis. Abbreviation: ΔΨm: mitochondrial transmembrane potential; AMP: adenosine monophosphate; AMPK: AMP-activated protein kinase; ATG5: autophagy related 5; ATP: adenosine triphosphate; ATP6V0A1: ATPase, H+ transporting, lysosomal, V0 subbunit A1; ATP6V1A: ATPase, H+ transporting, lysosomal, V0 subbunit A; BSA: bovine serum albumin; CCCP: carbonyl cyanide-m-chlorophenylhydrazone; CREB1: cAMP response element binding protein 1; CTSD: cathepsin D; CTSF: cathepsin F; DMEM: Dulbecco’s modified Eagle’s medium; DMSO: dimethyl sulfoxide; EBSS: Earl’s balanced salt solution; ER: endoplasmic reticulum; FBS: fetal bovine serum; FCCP: carbonyl cyanide-p-trifluoromethoxyphenolhydrazone; GFP: green fluorescent protein; GPN: glycyl-L-phenylalanine 2-naphthylamide; LAMP1: lysosomal associated membrane protein 1; MAP1LC3B/LC3B: microtubule associated protein 1 light chain 3 beta; MCOLN1/TRPML1: mucolipin 1; MEF: mouse embryonic fibroblast; MITF: melanocyte inducing transcription factor; ML1N*2-GFP: probe used to detect PtdIns(3,5)P2 based on the transmembrane domain of MCOLN1; MTORC1: mechanistic target of rapamycin kinase complex 1; NDUFS4: NADH:ubiquinone oxidoreductase subunit S4; OCR: oxygen consumption rate; PBS: phosphate-buffered saline; pcDNA: plasmid cytomegalovirus promoter DNA; PCR: polymerase chain reaction; PtdIns3P: phosphatidylinositol-3-phosphate; PtdIns(3,5)P2: phosphatidylinositol-3,5-bisphosphate; PIKFYVE: phosphoinositide kinase, FYVE-type zinc finger containing; P/S: penicillin-streptomycin; PVDF: polyvinylidene fluoride; qPCR: quantitative real time polymerase chain reaction; RFP: red fluorescent protein; RNA: ribonucleic acid; SDS-PAGE: sodium dodecyl sulfate polyacrylamide gel electrophoresis; shRNA: short hairpin RNA; siRNA: small interfering RNA; TFEB: transcription factor EB; TFE3: transcription factor binding to IGHM enhancer 3; TMRM: tetramethylrhodamine, methyl ester, perchlorate; ULK1: unc-51 like autophagy activating kinase 1; ULK2: unc-51 like autophagy activating kinase 2; UQCRC1: ubiquinol-cytochrome c reductase core protein 1; v-ATPase: vacuolar-type H+-translocating ATPase; WT: wild-type
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Affiliation(s)
- Lorena Fernandez-Mosquera
- a Institute of Cellular Biochemistry, University Medical Center Goettingen , Goettingen , Germany.,b Doctoral Program in Molecular Medicine, Georg August University Goettingen , Goettingen , Germany
| | - King Faisal Yambire
- a Institute of Cellular Biochemistry, University Medical Center Goettingen , Goettingen , Germany.,c International Max-Planck Research School in Neuroscience , Goettingen , Germany.,d European Neuroscience Institute Goettingen, University Medical Center Goettingen and Max-Planck Society , Goettingen , Germany
| | - Renata Couto
- a Institute of Cellular Biochemistry, University Medical Center Goettingen , Goettingen , Germany.,e Doctoral Program in Molecular Biology of Cells, Göttingen Graduate School for Neurosciences, Biophysics, and Molecular Biosciences, University of Goettingen , Goettingen , Germany
| | - Leonardo Pereyra
- a Institute of Cellular Biochemistry, University Medical Center Goettingen , Goettingen , Germany.,e Doctoral Program in Molecular Biology of Cells, Göttingen Graduate School for Neurosciences, Biophysics, and Molecular Biosciences, University of Goettingen , Goettingen , Germany
| | - Kamil Pabis
- a Institute of Cellular Biochemistry, University Medical Center Goettingen , Goettingen , Germany
| | - Amy H Ponsford
- f Institute of Translational Medicine, University of Liverpool , Liverpool , UK
| | - Cátia V Diogo
- a Institute of Cellular Biochemistry, University Medical Center Goettingen , Goettingen , Germany
| | - Massimiliano Stagi
- f Institute of Translational Medicine, University of Liverpool , Liverpool , UK
| | - Ira Milosevic
- d European Neuroscience Institute Goettingen, University Medical Center Goettingen and Max-Planck Society , Goettingen , Germany
| | - Nuno Raimundo
- a Institute of Cellular Biochemistry, University Medical Center Goettingen , Goettingen , Germany
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69
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Abstract
Polyphosphoinositides (PPIn) are essential signaling phospholipids that make remarkable contributions to the identity of all cellular membranes and signaling cascades in mammalian cells. They exert regulatory control over membrane homeostasis via selective interactions with cellular proteins at the membrane–cytoplasm interface. This review article briefly summarizes our current understanding of the key roles that PPIn play in orchestrating and regulating crucial electrical and chemical signaling events in mammalian neurons and the significant neuro-pathophysiological conditions that arise following alterations in their metabolism.
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Affiliation(s)
- Eamonn James Dickson
- Department Physiology and Membrane Biology, University of California, Davis, CA, 95616, USA
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70
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Lenk GM, Berry IR, Stutterd CA, Blyth M, Green L, Vadlamani G, Warren D, Craven I, Fanjul-Fernandez M, Rodriguez-Casero V, Lockhart PJ, Vanderver A, Simons C, Gibb S, Sadedin S, White SM, Christodoulou J, Skibina O, Ruddle J, Tan TY, Leventer RJ, Livingston JH, Meisler MH. Cerebral hypomyelination associated with biallelic variants of FIG4. Hum Mutat 2019; 40:619-630. [PMID: 30740813 DOI: 10.1002/humu.23720] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Revised: 12/11/2018] [Accepted: 02/06/2019] [Indexed: 01/07/2023]
Abstract
The lipid phosphatase gene FIG4 is responsible for Yunis-Varón syndrome and Charcot-Marie-Tooth disease Type 4J, a peripheral neuropathy. We now describe four families with FIG4 variants and prominent abnormalities of central nervous system (CNS) white matter (leukoencephalopathy), with onset in early childhood, ranging from severe hypomyelination to mild undermyelination, in addition to peripheral neuropathy. Affected individuals inherited biallelic FIG4 variants from heterozygous parents. Cultured fibroblasts exhibit enlarged vacuoles characteristic of FIG4 dysfunction. Two unrelated families segregate the same G > A variant in the +1 position of intron 21 in the homozygous state in one family and compound heterozygous in the other. This mutation in the splice donor site of exon 21 results in read-through from exon 20 into intron 20 and truncation of the final 115 C-terminal amino acids of FIG4, with retention of partial function. The observed CNS white matter disorder in these families is consistent with the myelination defects in the FIG4 null mouse and the known role of FIG4 in oligodendrocyte maturation. The families described here the expanded clinical spectrum of FIG4 deficiency to include leukoencephalopathy.
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Affiliation(s)
- Guy M Lenk
- Department of Human Genetics, University of Michigan, Ann Arbor, Michigan
| | - Ian R Berry
- Leeds Genetics Laboratory, The Leeds Teaching Hospitals NHS Trust, St James's University Hospital, Leeds, UK
| | - Chloe A Stutterd
- Murdoch Children's Research Institute, Melbourne, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, Australia.,Royal Children's Hospital, Melbourne, Australia
| | - Moira Blyth
- Yorkshire Regional Genetics Service, The Leeds Teaching Hospitals NHS Trust, Chapel Allerton Hospital, Leeds, UK
| | - Lydia Green
- Paediatric Neurology, The Leeds Teaching Hospitals NHS Trust, Leeds General Infirmary, Leeds, UK
| | - Gayatri Vadlamani
- Paediatric Neurology, The Leeds Teaching Hospitals NHS Trust, Leeds General Infirmary, Leeds, UK
| | - Daniel Warren
- The Leeds Teaching Hospitals NHS Trust, Leeds General Infirmary, Leeds, UK
| | - Ian Craven
- The Leeds Teaching Hospitals NHS Trust, Leeds General Infirmary, Leeds, UK
| | - Miriam Fanjul-Fernandez
- Murdoch Children's Research Institute, Melbourne, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, Australia
| | | | - Paul J Lockhart
- Murdoch Children's Research Institute, Melbourne, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, Australia
| | - Adeline Vanderver
- Division of Neurology, Children's Hospital of Philadelphia and Perlman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Cas Simons
- Murdoch Children's Research Institute, Melbourne, Australia.,Institute for Molecular Bioscience, University of Queensland, St Lucia, Australia
| | - Susan Gibb
- Department of Paediatrics, University of Melbourne, Melbourne, Australia.,Royal Children's Hospital, Melbourne, Australia
| | - Simon Sadedin
- Murdoch Children's Research Institute, Melbourne, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, Australia
| | | | - Susan M White
- Murdoch Children's Research Institute, Melbourne, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, Australia.,Victorian Clinical Genetics Services, Melbourne, Australia
| | - John Christodoulou
- Murdoch Children's Research Institute, Melbourne, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, Australia.,Victorian Clinical Genetics Services, Melbourne, Australia
| | - Olga Skibina
- Eastern Health Neurosciences, Box Hill Hospital, Monash University, Melbourne, Australia
| | - Jonathan Ruddle
- Royal Children's Hospital, Melbourne, Australia.,Centre for Eye Research Australia Ltd, East Melbourne, Victoria, Australia.,Department of Ophthalmology, University of Melbourne, Melbourne, Australia
| | - Tiong Y Tan
- Murdoch Children's Research Institute, Melbourne, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, Australia.,Victorian Clinical Genetics Services, Melbourne, Australia
| | - Richard J Leventer
- Murdoch Children's Research Institute, Melbourne, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, Australia.,Royal Children's Hospital, Melbourne, Australia
| | - John H Livingston
- Paediatric Neurology, The Leeds Teaching Hospitals NHS Trust, Leeds General Infirmary, Leeds, UK
| | - Miriam H Meisler
- Department of Human Genetics, University of Michigan, Ann Arbor, Michigan
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71
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Bissig C, Croisé P, Heiligenstein X, Hurbain I, Lenk GM, Kaufman E, Sannerud R, Annaert W, Meisler MH, Weisman LS, Raposo G, van Niel G. The PIKfyve complex regulates the early melanosome homeostasis required for physiological amyloid formation. J Cell Sci 2019; 132:jcs.229500. [PMID: 30709920 DOI: 10.1242/jcs.229500] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Accepted: 01/14/2019] [Indexed: 12/23/2022] Open
Abstract
The metabolism of PI(3,5)P2 is regulated by the PIKfyve, VAC14 and FIG4 complex, mutations in which are associated with hypopigmentation in mice. These pigmentation defects indicate a key, but as yet unexplored, physiological relevance of this complex in the biogenesis of melanosomes. Here, we show that PIKfyve activity regulates formation of amyloid matrix composed of PMEL protein within the early endosomes in melanocytes, called stage I melanosomes. PIKfyve activity controls the membrane remodeling of stage I melanosomes, which regulates PMEL abundance, sorting and processing. PIKfyve activity also affects stage I melanosome kiss-and-run interactions with lysosomes, which are required for PMEL amyloidogenesis and the establishment of melanosome identity. Mechanistically, PIKfyve activity promotes both the formation of membrane tubules from stage I melanosomes and their release by modulating endosomal actin branching. Taken together, our data indicate that PIKfyve activity is a key regulator of the melanosomal import-export machinery that fine tunes the formation of functional amyloid fibrils in melanosomes and the maintenance of melanosome identity.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Christin Bissig
- Structure and Membrane Compartments, Institut Curie, Paris Sciences & Lettres Research University, Centre National de la Recherche Scientifique, UMR144, 75005 Paris, France
| | - Pauline Croisé
- IPNP, Institute of Psychiatry and Neuroscience of Paris, Hopital Saint-Anne, Université Paris Descartes, INSERM U894, 75014 Paris, France
| | - Xavier Heiligenstein
- Structure and Membrane Compartments, Institut Curie, Paris Sciences & Lettres Research University, Centre National de la Recherche Scientifique, UMR144, 75005 Paris, France.,Cell and Tissue Imaging Facility, Institut Curie, Paris Sciences & Lettres Research University, Centre National de la Recherche Scientifique, UMR144, 75005 Paris, France
| | - Ilse Hurbain
- Structure and Membrane Compartments, Institut Curie, Paris Sciences & Lettres Research University, Centre National de la Recherche Scientifique, UMR144, 75005 Paris, France.,Cell and Tissue Imaging Facility, Institut Curie, Paris Sciences & Lettres Research University, Centre National de la Recherche Scientifique, UMR144, 75005 Paris, France
| | - Guy M Lenk
- Department of Human Genetics, University of Michigan, Ann Arbor, MI 48109-5618, USA
| | - Emily Kaufman
- Life Science Institute, University of Michigan, Ann Arbor, MI 48109-2216, USA
| | - Ragna Sannerud
- VIB Center for Brain & Disease Research, 3000 Leuven, Belgium.,KU Leuven, Department of Neurosciences, 3000 Leuven, Belgium
| | - Wim Annaert
- VIB Center for Brain & Disease Research, 3000 Leuven, Belgium.,KU Leuven, Department of Neurosciences, 3000 Leuven, Belgium
| | - Miriam H Meisler
- Department of Human Genetics, University of Michigan, Ann Arbor, MI 48109-5618, USA
| | - Lois S Weisman
- Life Science Institute, University of Michigan, Ann Arbor, MI 48109-2216, USA
| | - Graça Raposo
- Structure and Membrane Compartments, Institut Curie, Paris Sciences & Lettres Research University, Centre National de la Recherche Scientifique, UMR144, 75005 Paris, France.,Cell and Tissue Imaging Facility, Institut Curie, Paris Sciences & Lettres Research University, Centre National de la Recherche Scientifique, UMR144, 75005 Paris, France
| | - Guillaume van Niel
- Structure and Membrane Compartments, Institut Curie, Paris Sciences & Lettres Research University, Centre National de la Recherche Scientifique, UMR144, 75005 Paris, France .,IPNP, Institute of Psychiatry and Neuroscience of Paris, Hopital Saint-Anne, Université Paris Descartes, INSERM U894, 75014 Paris, France.,Cell and Tissue Imaging Facility, Institut Curie, Paris Sciences & Lettres Research University, Centre National de la Recherche Scientifique, UMR144, 75005 Paris, France
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72
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Li P, Gu M, Xu H. Lysosomal Ion Channels as Decoders of Cellular Signals. Trends Biochem Sci 2019; 44:110-124. [PMID: 30424907 PMCID: PMC6340733 DOI: 10.1016/j.tibs.2018.10.006] [Citation(s) in RCA: 100] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 10/09/2018] [Accepted: 10/15/2018] [Indexed: 02/08/2023]
Abstract
Lysosomes, the degradation center of the cell, are filled with acidic hydrolases. Lysosomes generate nutrient-sensitive signals to regulate the import of H+, hydrolases, and endocytic and autophagic cargos, as well as the export of their degradation products (catabolites). In response to environmental and cellular signals, lysosomes change their positioning, number, morphology, size, composition, and activity within minutes to hours to meet the changing cellular needs. Ion channels in the lysosome are essential transducers that mediate signal-initiated Ca2+/Fe2+/Zn2+ release and H+/Na+/K+-dependent changes of membrane potential across the perimeter membrane. Dysregulation of lysosomal ion flux impairs lysosome movement, membrane trafficking, nutrient sensing, membrane repair, organelle membrane contact, and lysosome biogenesis and adaptation. Hence, activation and inhibition of lysosomal channels by synthetic modulators may tune lysosome function to maintain cellular health and promote cellular clearance in lysosome storage disorders.
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Affiliation(s)
- Ping Li
- Collaborative Innovation Center of Yangtze River Delta Region Green Pharmaceuticals, College of Pharmaceutical Sciences, Zhejiang University of Technology, Hangzhou 310014, China; Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA; These authors contributed equally to this work
| | - Mingxue Gu
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA; These authors contributed equally to this work
| | - Haoxing Xu
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA.
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73
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Buckley CM, Heath VL, Guého A, Bosmani C, Knobloch P, Sikakana P, Personnic N, Dove SK, Michell RH, Meier R, Hilbi H, Soldati T, Insall RH, King JS. PIKfyve/Fab1 is required for efficient V-ATPase and hydrolase delivery to phagosomes, phagosomal killing, and restriction of Legionella infection. PLoS Pathog 2019; 15:e1007551. [PMID: 30730983 PMCID: PMC6382210 DOI: 10.1371/journal.ppat.1007551] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Revised: 02/20/2019] [Accepted: 01/03/2019] [Indexed: 12/11/2022] Open
Abstract
By engulfing potentially harmful microbes, professional phagocytes are continually at risk from intracellular pathogens. To avoid becoming infected, the host must kill pathogens in the phagosome before they can escape or establish a survival niche. Here, we analyse the role of the phosphoinositide (PI) 5-kinase PIKfyve in phagosome maturation and killing, using the amoeba and model phagocyte Dictyostelium discoideum. PIKfyve plays important but poorly understood roles in vesicular trafficking by catalysing formation of the lipids phosphatidylinositol (3,5)-bisphosphate (PI(3,5)2) and phosphatidylinositol-5-phosphate (PI(5)P). Here we show that its activity is essential during early phagosome maturation in Dictyostelium. Disruption of PIKfyve inhibited delivery of both the vacuolar V-ATPase and proteases, dramatically reducing the ability of cells to acidify newly formed phagosomes and digest their contents. Consequently, PIKfyve- cells were unable to generate an effective antimicrobial environment and efficiently kill captured bacteria. Moreover, we demonstrate that cells lacking PIKfyve are more susceptible to infection by the intracellular pathogen Legionella pneumophila. We conclude that PIKfyve-catalysed phosphoinositide production plays a crucial and general role in ensuring early phagosomal maturation, protecting host cells from diverse pathogenic microbes.
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Affiliation(s)
- Catherine M. Buckley
- Centre for Membrane Interactions and Dynamics, Department of Biomedical Sciences, University of Sheffield, Firth Court, Western Bank, Sheffield, United Kingdom
- Bateson Centre, University of Sheffield, Firth Court, Western Bank, Sheffield, United Kingdom
| | - Victoria L. Heath
- Institute of Cardiovascular Sciences, Institute for Biomedical Research, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
| | - Aurélie Guého
- Department of Biochemistry, Faculty of Sciences, University of Geneva, Geneva, Switzerland
| | - Cristina Bosmani
- Department of Biochemistry, Faculty of Sciences, University of Geneva, Geneva, Switzerland
| | - Paulina Knobloch
- Institute of Medical Microbiology, University of Zürich, Zürich, Switzerland
| | - Phumzile Sikakana
- Centre for Membrane Interactions and Dynamics, Department of Biomedical Sciences, University of Sheffield, Firth Court, Western Bank, Sheffield, United Kingdom
| | - Nicolas Personnic
- Institute of Medical Microbiology, University of Zürich, Zürich, Switzerland
| | - Stephen K. Dove
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
| | - Robert H. Michell
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
| | - Roger Meier
- Institute of Molecular Life Sciences, University of Zürich, Zürich, Switzerland
| | - Hubert Hilbi
- Institute of Medical Microbiology, University of Zürich, Zürich, Switzerland
| | - Thierry Soldati
- Department of Biochemistry, Faculty of Sciences, University of Geneva, Geneva, Switzerland
| | - Robert H. Insall
- CRUK Beatson Institute, Switchback Road, Bearsden, Glasgow, United Kingdom
| | - Jason S. King
- Centre for Membrane Interactions and Dynamics, Department of Biomedical Sciences, University of Sheffield, Firth Court, Western Bank, Sheffield, United Kingdom
- Bateson Centre, University of Sheffield, Firth Court, Western Bank, Sheffield, United Kingdom
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74
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Understanding phosphoinositides: rare, dynamic, and essential membrane phospholipids. Biochem J 2019; 476:1-23. [PMID: 30617162 DOI: 10.1042/bcj20180022] [Citation(s) in RCA: 153] [Impact Index Per Article: 30.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Revised: 12/03/2018] [Accepted: 12/07/2018] [Indexed: 12/15/2022]
Abstract
Polyphosphoinositides (PPIs) are essential phospholipids located in the cytoplasmic leaflet of eukaryotic cell membranes. Despite contributing only a small fraction to the bulk of cellular phospholipids, they make remarkable contributions to practically all aspects of a cell's life and death. They do so by recruiting cytoplasmic proteins/effectors or by interacting with cytoplasmic domains of membrane proteins at the membrane-cytoplasm interface to organize and mold organelle identity. The present study summarizes aspects of our current understanding concerning the metabolism, manipulation, measurement, and intimate roles these lipids play in regulating membrane homeostasis and vital cell signaling reactions in health and disease.
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75
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Pemberton JG, Balla T. Polyphosphoinositide-Binding Domains: Insights from Peripheral Membrane and Lipid-Transfer Proteins. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1111:77-137. [PMID: 30483964 DOI: 10.1007/5584_2018_288] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Within eukaryotic cells, biochemical reactions need to be organized on the surface of membrane compartments that use distinct lipid constituents to dynamically modulate the functions of integral proteins or influence the selective recruitment of peripheral membrane effectors. As a result of these complex interactions, a variety of human pathologies can be traced back to improper communication between proteins and membrane surfaces; either due to mutations that directly alter protein structure or as a result of changes in membrane lipid composition. Among the known structural lipids found in cellular membranes, phosphatidylinositol (PtdIns) is unique in that it also serves as the membrane-anchored precursor of low-abundance regulatory lipids, the polyphosphoinositides (PPIn), which have restricted distributions within specific subcellular compartments. The ability of PPIn lipids to function as signaling platforms relies on both non-specific electrostatic interactions and the selective stereospecific recognition of PPIn headgroups by specialized protein folds. In this chapter, we will attempt to summarize the structural diversity of modular PPIn-interacting domains that facilitate the reversible recruitment and conformational regulation of peripheral membrane proteins. Outside of protein folds capable of capturing PPIn headgroups at the membrane interface, recent studies detailing the selective binding and bilayer extraction of PPIn species by unique functional domains within specific families of lipid-transfer proteins will also be highlighted. Overall, this overview will help to outline the fundamental physiochemical mechanisms that facilitate localized interactions between PPIn lipids and the wide-variety of PPIn-binding proteins that are essential for the coordinate regulation of cellular metabolism and membrane dynamics.
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Affiliation(s)
- Joshua G Pemberton
- Section on Molecular Signal Transduction, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Tamas Balla
- Section on Molecular Signal Transduction, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA.
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76
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Lee JW, Nam H, Kim LE, Jeon Y, Min H, Ha S, Lee Y, Kim SY, Lee SJ, Kim EK, Yu SW. TLR4 (toll-like receptor 4) activation suppresses autophagy through inhibition of FOXO3 and impairs phagocytic capacity of microglia. Autophagy 2018; 15:753-770. [PMID: 30523761 DOI: 10.1080/15548627.2018.1556946] [Citation(s) in RCA: 145] [Impact Index Per Article: 24.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Macroautophagy/autophagy is a lysosome-dependent catabolic process for the turnover of proteins and organelles in eukaryotes. Autophagy plays an important role in immunity and inflammation, as well as metabolism and cell survival. Diverse immune and inflammatory signals induce autophagy in macrophages through pattern recognition receptors, such as toll-like receptors (TLRs). However, the physiological role of autophagy and its signaling mechanisms in microglia remain poorly understood. Microglia are phagocytic immune cells that are resident in the central nervous system and share many characteristics with macrophages. Here, we show that autophagic flux and expression of autophagy-related (Atg) genes in microglia are significantly suppressed upon TLR4 activation by lipopolysaccharide (LPS), in contrast to their stimulation by LPS in macrophages. Metabolomics analysis of the levels of phosphatidylinositol (PtdIns) and its 3-phosphorylated form, PtdIns3P, in combination with bioinformatics prediction, revealed an LPS-induced reduction in the synthesis of PtdIns and PtdIns3P in microglia but not macrophages. Interestingly, inhibition of PI3K, but not MTOR or MAPK1/3, restored autophagic flux with concomitant dephosphorylation and nuclear translocation of FOXO3. A constitutively active form of FOXO3 also induced autophagy, suggesting FOXO3 as a downstream target of the PI3K pathway for autophagy inhibition. LPS treatment impaired phagocytic capacity of microglia, including MAP1LC3B/LC3-associated phagocytosis (LAP) and amyloid β (Aβ) clearance. PI3K inhibition restored LAP and degradation capacity of microglia against Aβ. These findings suggest a unique mechanism for the regulation of microglial autophagy and point to the PI3K-FOXO3 pathway as a potential therapeutic target to regulate microglial function in brain disorders. Abbreviations: Atg: autophagy-related gene; Aβ: amyloid-β; BafA1: bafilomycin A1; BECN1: beclin 1, autophagy related; BMDM: bone marrow-derived macrophage; CA: constitutively active; CNS: central nervous system; ZFYVE1/DFCP1: zinc finger, FYVE domain containing 1; FOXO: forkhead box O; ELISA:enzyme-linked immunosorbent assay; HBSS: Hanks balanced salt solution; LAP: LC3-associated phagocytosis; MAP1LC3B: microtubule-associated protein 1 light chain 3; LPS: lipopolysaccharide; LY: LY294002; MTOR: mechanistic target of rapamycin kinase; Pam3CSK4: N-palmitoyl-S-dipalmitoylglyceryl Cys-Ser-(Lys)4; PtdIns: phosphatidylinositol; PtdIns3P: phosphatidylinositol-3-phosphate; PLA: proximity ligation assay; Poly(I:C): polyinosinic-polycytidylic acid; qRT-PCR: quantitative real-time polymerase chain reaction; RPS6KB1: ribosomal protein S6 kinase, polypeptide 1; TLR: Toll-like receptor; TNF: tumor necrosis factor; TFEB: transcription factor EB; TSPO: translocator protein.
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Affiliation(s)
- Ji-Won Lee
- a Department of Brain and Cognitive Sciences , Daegu Gyeongbuk Institute of Science and Technology (DGIST) , Daegu , Republic of Korea
| | - Hyeri Nam
- a Department of Brain and Cognitive Sciences , Daegu Gyeongbuk Institute of Science and Technology (DGIST) , Daegu , Republic of Korea
| | - Leah Eunjung Kim
- a Department of Brain and Cognitive Sciences , Daegu Gyeongbuk Institute of Science and Technology (DGIST) , Daegu , Republic of Korea
| | - Yoonjeong Jeon
- a Department of Brain and Cognitive Sciences , Daegu Gyeongbuk Institute of Science and Technology (DGIST) , Daegu , Republic of Korea.,b Neurometabolomics Research Center , Daegu Gyeongbuk Institute of Science and Technology (DGIST) , Daegu , Republic of Korea
| | - Hyunjung Min
- c Department of Neuroscience and Physiology , Dental Research Institute, School of Dentistry, Seoul National University , Seoul , Republic of Korea
| | - Shinwon Ha
- a Department of Brain and Cognitive Sciences , Daegu Gyeongbuk Institute of Science and Technology (DGIST) , Daegu , Republic of Korea
| | - Younghwan Lee
- a Department of Brain and Cognitive Sciences , Daegu Gyeongbuk Institute of Science and Technology (DGIST) , Daegu , Republic of Korea
| | - Seon-Young Kim
- d Gene Editing Research Center , KRIBB , Daejeon , Republic of Korea
| | - Sung Joong Lee
- c Department of Neuroscience and Physiology , Dental Research Institute, School of Dentistry, Seoul National University , Seoul , Republic of Korea
| | - Eun-Kyoung Kim
- a Department of Brain and Cognitive Sciences , Daegu Gyeongbuk Institute of Science and Technology (DGIST) , Daegu , Republic of Korea.,b Neurometabolomics Research Center , Daegu Gyeongbuk Institute of Science and Technology (DGIST) , Daegu , Republic of Korea
| | - Seong-Woon Yu
- a Department of Brain and Cognitive Sciences , Daegu Gyeongbuk Institute of Science and Technology (DGIST) , Daegu , Republic of Korea.,b Neurometabolomics Research Center , Daegu Gyeongbuk Institute of Science and Technology (DGIST) , Daegu , Republic of Korea
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77
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Akt1 inhibition promotes breast cancer metastasis through EGFR-mediated β-catenin nuclear accumulation. Cell Commun Signal 2018; 16:82. [PMID: 30445978 PMCID: PMC6240210 DOI: 10.1186/s12964-018-0295-1] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Accepted: 11/06/2018] [Indexed: 12/11/2022] Open
Abstract
Background Knockdown of Akt1 promotes Epithelial-to-Mesenchymal Transition in breast cancer cells. However, the mechanisms are not completely understood. Methods Western blotting, immunofluorescence, luciferase assay, real time PCR, ELISA and Matrigel invasion assay were used to investigate how Akt1 inhibition promotes breast cancer cell invasion in vitro. Mouse model of lung metastasis was used to measure in vivo efficacy of Akt inhibitor MK2206 and its combination with Gefitinib. Results Knockdown of Akt1 stimulated β-catenin nuclear accumulation, resulting in breast cancer cell invasion. β-catenin nuclear accumulation induced by Akt1 inhibition depended on the prolonged activation of EGFR signaling pathway in breast cancer cells. Mechanistic experiments documented that knockdown of Akt1 inactivates PIKfyve via dephosphorylating of PIKfyve at Ser318 site, resulting in a decreased degradation of EGFR signaling pathway. Inhibition of Akt1 using MK2206 could induce an increase in the expression of EGFR and β-catenin in breast cancer cells. In addition, MK2206 at a low dosage enhance breast cancer metastasis in a mouse model of lung metastasis, while an inhibitor of EGFR tyrosine kinase Gefitinib could potentially suppress breast cancer metastasis induced by Akt1 inhibition. Conclusion EGFR-mediated β-catenin nuclear accumulation is critical for Akt1 inhibition-induced breast cancer metastasis.
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78
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Michgehl U, Skryabin BV, Bayraktar S, Vollenbröker B, Ciarimboli G, Heitplatz B, Van Marck V, Gröne HJ, Pavenstädt H, Weide T. Nephron-specific knockin of the PIKfyve-binding-deficient Vac14 L156R mutant results in albuminuria and mesangial expansion. Am J Physiol Renal Physiol 2018; 315:F1307-F1319. [PMID: 30066585 DOI: 10.1152/ajprenal.00191.2018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Intracellular trafficking processes play a key role for the establishment and maintenance of membrane surfaces in renal epithelia. Therefore, dysfunctions of these trafficking processes could be key events and important determinants in the onset and progression of diseases. The presence of cellular vacuoles-observed in many histologic analyses of renal diseases-is a macroscopic hint for disturbed intracellular trafficking processes. However, how vacuoles develop and which intracellular pathways are directly affected remain largely unknown. Previous studies showed that in some cases, vacuolization is linked to malfunction of the Vac14 complex. This complex, including the scaffold protein Vac14, the lipid kinase PIKfyve, and its counteracting lipid phosphatase Fig4, regulates intracellular phosphatidylinositol phosphate levels, which in turn, control the maturation of early-into-late endosomes, as well as the processing of autophagosomes into autophagolysosomes. Here, we analyzed the role of Vac14 in mice and observed that the nephron-specific knockin of the PIKfyve-binding-deficient Vac14L156R mutant led to albuminuria, accompanied by mesangial expansion, increased glomerular size, and an elevated expression of several kidney injury markers. Overexpression of this Vac14 variant in podocytes did not reveal a strong in vivo phenotype, indicating that Vac14-dependent trafficking processes are more important for tubular than for glomerular processes in the kidney. In vitro overexpression of Vac14L156R in Madin-Darby canine kidney cells had no impact on apico-basal polarity defects but resulted in a faster reassembly of junctional structures after Ca2+ depletion and delayed endo- and transcytosis rates. Taken together, our data suggest that increased albuminuria of Vac14L156R-overexpressing mice is a consequence of a lowered endo- and transcytosis of albumin in renal tubules.
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Affiliation(s)
- Ulf Michgehl
- Internal Medicine D, University Hospital Muenster , Muenster , Germany
| | - Boris V Skryabin
- Department of Medicine, Transgenic Animal and Genetic Engineering Models, University of Muenster , Muenster , Germany
| | - Samet Bayraktar
- Internal Medicine D, University Hospital Muenster , Muenster , Germany
| | | | | | - Barbara Heitplatz
- Institute for Pathology, University Hospital Muenster , Muenster , Germany
| | - Veerle Van Marck
- Institute for Pathology, University Hospital Muenster , Muenster , Germany
| | - Hermann-Josef Gröne
- Department of Cellular and Molecular Pathology, Deutsches Krebsforschungszentrum, Heidelberg , Germany
| | | | - Thomas Weide
- Internal Medicine D, University Hospital Muenster , Muenster , Germany
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79
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Phospholipids and inositol phosphates linked to the epigenome. Histochem Cell Biol 2018; 150:245-253. [DOI: 10.1007/s00418-018-1690-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/15/2018] [Indexed: 12/17/2022]
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80
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Choy CH, Saffi G, Gray MA, Wallace C, Dayam RM, Ou ZYA, Lenk G, Puertollano R, Watkins SC, Botelho RJ. Lysosome enlargement during inhibition of the lipid kinase PIKfyve proceeds through lysosome coalescence. J Cell Sci 2018; 131:jcs.213587. [PMID: 29661845 DOI: 10.1242/jcs.213587] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Accepted: 04/10/2018] [Indexed: 01/07/2023] Open
Abstract
Lysosomes receive and degrade cargo from endocytosis, phagocytosis and autophagy. They also play an important role in sensing and instructing cells on their metabolic state. The lipid kinase PIKfyve generates phosphatidylinositol-3,5-bisphosphate to modulate lysosome function. PIKfyve inhibition leads to impaired degradative capacity, ion dysregulation, abated autophagic flux and a massive enlargement of lysosomes. Collectively, this leads to various physiological defects, including embryonic lethality, neurodegeneration and overt inflammation. The reasons for such drastic lysosome enlargement remain unclear. Here, we examined whether biosynthesis and/or fusion-fission dynamics contribute to swelling. First, we show that PIKfyve inhibition activates TFEB, TFE3 and MITF, enhancing lysosome gene expression. However, this did not augment lysosomal protein levels during acute PIKfyve inhibition, and deletion of TFEB and/or related proteins did not impair lysosome swelling. Instead, PIKfyve inhibition led to fewer but enlarged lysosomes, suggesting that an imbalance favouring lysosome fusion over fission causes lysosome enlargement. Indeed, conditions that abated fusion curtailed lysosome swelling in PIKfyve-inhibited cells.
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Affiliation(s)
- Christopher H Choy
- Department of Chemistry and Biology, Ryerson University, Toronto, ON, Canada, M5B2K3.,The Graduate Program in Molecular Science, Ryerson University, Toronto, ON, Canada, M5B2K3
| | - Golam Saffi
- Department of Chemistry and Biology, Ryerson University, Toronto, ON, Canada, M5B2K3.,The Graduate Program in Molecular Science, Ryerson University, Toronto, ON, Canada, M5B2K3
| | - Matthew A Gray
- Department of Chemistry and Biology, Ryerson University, Toronto, ON, Canada, M5B2K3
| | - Callen Wallace
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Roya M Dayam
- Department of Chemistry and Biology, Ryerson University, Toronto, ON, Canada, M5B2K3.,The Graduate Program in Molecular Science, Ryerson University, Toronto, ON, Canada, M5B2K3
| | - Zhen-Yi A Ou
- Department of Chemistry and Biology, Ryerson University, Toronto, ON, Canada, M5B2K3
| | - Guy Lenk
- Department of Human Genetics, University of Michigan, Ann Arbor, MI 48109, USA
| | - Rosa Puertollano
- Cell Biology and Physiology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, 50 South Drive, Building 50, Room 3537, Bethesda, MD 20892, USA
| | - Simon C Watkins
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Roberto J Botelho
- Department of Chemistry and Biology, Ryerson University, Toronto, ON, Canada, M5B2K3 .,The Graduate Program in Molecular Science, Ryerson University, Toronto, ON, Canada, M5B2K3
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81
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Abstract
The lysosome-like vacuole is the main organelle to degrade membrane proteins and organelles and, thus, provides amino acids, but also ions to the cytosol for cellular survival. Maintenance of vacuole membrane integrity is thus important for cellular adaptations. The vacuole contains several protein complexes on its surface to maintain the vacuole functional, and one such complex is a lipid kinase named Fab1 (of PIKfyve in human cells). Fab1 is part of a protein complex that produces a phosphorylated lipid, PI-3,5-P2. Other proteins bind PI-3,5-P2 and can fragment the vacuole to balance volume vs. membrane during stress. We now identify Ivy1 as a protein that binds Fab1 and controls its activity. Lysosomes have an important role in cellular protein and organelle quality control, metabolism, and signaling. On the surface of lysosomes, the PIKfyve/Fab1 complex generates phosphatidylinositol 3,5-bisphosphate, PI-3,5-P2, which is critical for lysosomal membrane homeostasis during acute osmotic stress and for lysosomal signaling. Here, we identify the inverted BAR protein Ivy1 as an inhibitor of the Fab1 complex with a direct influence on PI-3,5-P2 levels and vacuole homeostasis. Ivy1 requires Ypt7 binding for its function, binds PI-3,5-P2, and interacts with the Fab1 kinase. Colocalization of Ivy1 and Fab1 is lost during osmotic stress. In agreement with Ivy1’s role as a Fab1 regulator, its overexpression blocks Fab1 activity during osmotic shock and vacuole fragmentation. Conversely, loss of Ivy1, or lateral relocalization of Ivy1 on vacuoles away from Fab1, results in vacuole fragmentation and poor growth. Our data suggest that Ivy1 modulates Fab1-mediated PI-3,5-P2 synthesis during membrane stress and may allow adjustment of the vacuole membrane environment.
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82
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Fogarty K, Kashem M, Bauer A, Bernardino A, Brennan D, Cook B, Farrow N, Molinaro T, Nelson R. Development of Three Orthogonal Assays Suitable for the Identification and Qualification of PIKfyve Inhibitors. Assay Drug Dev Technol 2018; 15:210-219. [PMID: 28723271 DOI: 10.1089/adt.2017.790] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
FYVE-type zinc finger-containing phosphoinositide kinase (PIKfyve) catalyzes the formation of phosphatidylinositol 3,5-bisphosphate (PI(3,5)P2) from phosphatidylinositol 3-phosphate (PI(3)P). PIKfyve has been implicated in multiple cellular processes, and its role in the regulation of toll-like receptor (TLR) pathways and the production of proinflammatory cytokines has sparked interest in developing small-molecule PIKfyve inhibitors as potential therapeutics to treat autoimmune and inflammatory diseases. We developed three orthogonal assays to identify and qualify small-molecule inhibitors of PIKfyve: (1) a purified component microfluidic enzyme assay that measures the conversion of fluorescently labeled PI(3)P to PI(3,5)P2 by purified recombinant full-length human 6His-PIKfyve (rPIKfyve); (2) an intracellular protein stabilization assay using the kinase domain of PIKfyve expressed in HEK293 cells; and (3) a cell-based functional assay that measures the production of interleukin (IL)-12p70 in human peripheral blood mononuclear cells stimulated with TLR agonists lipopolysaccharide and R848. We determined apparent Km values for both ATP and labeled PI(3)P in the rPIKfyve enzyme assay and evaluated the enzyme's ability to use phosphatidylinositol as a substrate. We also tested four reference compounds in the three assays and showed that together these assays provide a platform that is suitable to select promising inhibitors having appropriate functional activity and confirmed cellular target engagement to advance into preclinical models of inflammation.
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Affiliation(s)
- Kylie Fogarty
- 1 Department of Small Molecule Discovery Research, Boehringer Ingelheim Pharmaceuticals, Inc. , Ridgefield, Connecticut
| | - Mohammed Kashem
- 1 Department of Small Molecule Discovery Research, Boehringer Ingelheim Pharmaceuticals, Inc. , Ridgefield, Connecticut
| | - Andras Bauer
- 2 Department of Immunology and Inflammation, Boehringer Ingelheim Pharmaceuticals, Inc. , Ridgefield, Connecticut
| | - Alexandra Bernardino
- 2 Department of Immunology and Inflammation, Boehringer Ingelheim Pharmaceuticals, Inc. , Ridgefield, Connecticut
| | - Debra Brennan
- 1 Department of Small Molecule Discovery Research, Boehringer Ingelheim Pharmaceuticals, Inc. , Ridgefield, Connecticut
| | - Brian Cook
- 1 Department of Small Molecule Discovery Research, Boehringer Ingelheim Pharmaceuticals, Inc. , Ridgefield, Connecticut
| | - Neil Farrow
- 1 Department of Small Molecule Discovery Research, Boehringer Ingelheim Pharmaceuticals, Inc. , Ridgefield, Connecticut
| | - Teresa Molinaro
- 1 Department of Small Molecule Discovery Research, Boehringer Ingelheim Pharmaceuticals, Inc. , Ridgefield, Connecticut
| | - Richard Nelson
- 1 Department of Small Molecule Discovery Research, Boehringer Ingelheim Pharmaceuticals, Inc. , Ridgefield, Connecticut
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83
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Liggins MC, Flesher JL, Jahid S, Vasudeva P, Eby V, Takasuga S, Sasaki J, Sasaki T, Boissy RE, Ganesan AK. PIKfyve regulates melanosome biogenesis. PLoS Genet 2018; 14:e1007290. [PMID: 29584722 PMCID: PMC5889185 DOI: 10.1371/journal.pgen.1007290] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Revised: 04/06/2018] [Accepted: 03/05/2018] [Indexed: 12/18/2022] Open
Abstract
PIKfyve, VAC14, and FIG4 form a complex that catalyzes the production of PI(3,5)P2, a signaling lipid implicated in process ranging from lysosome maturation to neurodegeneration. While previous studies have identified VAC14 and FIG4 mutations that lead to both neurodegeneration and coat color defects, how PIKfyve regulates melanogenesis is unknown. In this study, we sought to better understand the role of PIKfyve in melanosome biogenesis. Melanocyte-specific PIKfyve knockout mice exhibit greying of the mouse coat and the accumulation of single membrane vesicle structures in melanocytes resembling multivesicular endosomes. PIKfyve inhibition blocks melanosome maturation, the processing of the melanosome protein PMEL, and the trafficking of the melanosome protein TYRP1. Taken together, these studies identify a novel role for PIKfyve in controlling the delivery of proteins from the endosomal compartment to the melanosome, a role that is distinct from the role of PIKfyve in the reformation of lysosomes from endolysosomes.
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Affiliation(s)
- Marc C. Liggins
- Department of Dermatology, University of California, San Diego, San Diego, CA, United States of America
| | - Jessica L. Flesher
- Department of Biological Chemistry, University of California, Irvine, Irvine, CA, United States of America
| | - Sohail Jahid
- Department of Dermatology, University of California, Irvine, Irvine, CA, United States of America
| | - Priya Vasudeva
- Department of Dermatology, University of California, Irvine, Irvine, CA, United States of America
| | - Victoria Eby
- Department of Dermatology, University of Cincinnati, Cincinnati, OH, United States of America
| | - Shunsuke Takasuga
- Department of Medical Biology, Akita University School of Medicine, Akita, Japan
| | - Junko Sasaki
- Department of Medical Biology, Akita University School of Medicine, Akita, Japan
| | - Takehiko Sasaki
- Department of Medical Biology, Akita University School of Medicine, Akita, Japan
| | - Raymond E. Boissy
- Department of Dermatology, University of Cincinnati, Cincinnati, OH, United States of America
| | - Anand K. Ganesan
- Department of Biological Chemistry, University of California, Irvine, Irvine, CA, United States of America
- Department of Dermatology, University of California, Irvine, Irvine, CA, United States of America
- * E-mail:
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84
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Wengelnik K, Daher W, Lebrun M. Phosphoinositides and their functions in apicomplexan parasites. Int J Parasitol 2018; 48:493-504. [PMID: 29596862 DOI: 10.1016/j.ijpara.2018.01.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Revised: 01/26/2018] [Accepted: 01/29/2018] [Indexed: 11/28/2022]
Abstract
Phosphoinositides are the phosphorylated derivatives of the structural membrane phospholipid phosphatidylinositol. Single or combined phosphorylation at the 3, 4 and 5 positions of the inositol ring gives rise to the seven different species of phosphoinositides. All are quantitatively minor components of cellular membranes but have been shown to have important functions in multiple cellular processes. Here we describe our current knowledge of phosphoinositide metabolism and functions in apicomplexan parasites, mainly focusing on Toxoplasma gondii and Plasmodium spp. Even though our understanding is still rudimentary, phosphoinositides have already shown their importance in parasite biology and revealed some very particular and parasite-specific functions. Not surprisingly, there is a strong potential for phosphoinositide synthesis to be exploited for future anti-parasitic drug development.
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Affiliation(s)
- Kai Wengelnik
- Dynamique des Interactions Membranaires Normales et Pathologiques, UMR5235 CNRS, INSERM, Université Montpellier, Montpellier, France.
| | - Wassim Daher
- Dynamique des Interactions Membranaires Normales et Pathologiques, UMR5235 CNRS, INSERM, Université Montpellier, Montpellier, France
| | - Maryse Lebrun
- Dynamique des Interactions Membranaires Normales et Pathologiques, UMR5235 CNRS, INSERM, Université Montpellier, Montpellier, France.
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85
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Narayanan P, Hütte M, Kudryasheva G, Taberner FJ, Lechner SG, Rehfeldt F, Gomez-Varela D, Schmidt M. Myotubularin related protein-2 and its phospholipid substrate PIP 2 control Piezo2-mediated mechanotransduction in peripheral sensory neurons. eLife 2018. [PMID: 29521261 PMCID: PMC5898911 DOI: 10.7554/elife.32346] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Piezo2 ion channels are critical determinants of the sense of light touch in vertebrates. Yet, their regulation is only incompletely understood. We recently identified myotubularin related protein-2 (Mtmr2), a phosphoinositide (PI) phosphatase, in the native Piezo2 interactome of murine dorsal root ganglia (DRG). Here, we demonstrate that Mtmr2 attenuates Piezo2-mediated rapidly adapting mechanically activated (RA-MA) currents. Interestingly, heterologous Piezo1 and other known MA current subtypes in DRG appeared largely unaffected by Mtmr2. Experiments with catalytically inactive Mtmr2, pharmacological blockers of PI(3,5)P2 synthesis, and osmotic stress suggest that Mtmr2-dependent Piezo2 inhibition involves depletion of PI(3,5)P2. Further, we identified a PI(3,5)P2 binding region in Piezo2, but not Piezo1, that confers sensitivity to Mtmr2 as indicated by functional analysis of a domain-swapped Piezo2 mutant. Altogether, our results propose local PI(3,5)P2 modulation via Mtmr2 in the vicinity of Piezo2 as a novel mechanism to dynamically control Piezo2-dependent mechanotransduction in peripheral sensory neurons. We often take our sense of touch for granted. Yet, our every-day life greatly depends on the ability to perceive our environment to alert us of danger or to further social interactions, such as mother-child bonding. Our sense of touch relies on the conversion of mechanical stimuli to electrical signals (this is known as mechanotransduction), which then travel to brain to be processed. This task is fulfilled by specific ion channels called Piezo2, which are activated when cells are exposed to pressure and other mechanical forces. These channels can be found in sensory nerves and specialized structures in the skin, where they help to detect physical contact, roughness of surfaces and the position of our body parts. It is still not clear how Piezo2 channels are regulated but previous research by several laboratories suggests that they work in conjunction with other proteins. One of these proteins is the myotubularin related protein-2, or Mtmr2 for short. Now, Narayanan et al. – including some of the researchers involved in the previous research – set out to advance our understanding of the molecular basis of touch and looked more closely at Mtmr2. To test if Mtmr2 played a role in mechanotransduction, Narayanan et al. both increased and reduced the levels of this protein in sensory neurons of mice grown in the laboratory. When Mtmr2 levels were low, the activity of Piezo2 channels increased. However, when the protein levels were high, Piezo2 channels were inhibited. These results suggest that Mtmr2 can control the activity of Piezo2. Further experiments, in which Mtmr2 was genetically modified or sensory neurons were treated with chemicals, revealed that Mtmr2 reduces a specific fatty acid in the membrane of nerve cells, which in turn attenuates the activity of Piezo2. This study identified Mtmr2 and distinct fatty acids in the cell membrane as new components of the complex setup required for the sense of touch. A next step will be to test if these molecules also influence the activity of Piezo2 when the skin has become injured or upon inflammation.
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Affiliation(s)
- Pratibha Narayanan
- Emmy Noether-Group Somatosensory Signaling and Systems Biology, Max Planck Institute for Experimental Medicine, Goettingen, Germany
| | - Meike Hütte
- Emmy Noether-Group Somatosensory Signaling and Systems Biology, Max Planck Institute for Experimental Medicine, Goettingen, Germany
| | - Galina Kudryasheva
- Third Institute of Physics - Biophysics, University of Goettingen, Goettingen, Germany
| | | | | | - Florian Rehfeldt
- Third Institute of Physics - Biophysics, University of Goettingen, Goettingen, Germany
| | - David Gomez-Varela
- Emmy Noether-Group Somatosensory Signaling and Systems Biology, Max Planck Institute for Experimental Medicine, Goettingen, Germany
| | - Manuela Schmidt
- Emmy Noether-Group Somatosensory Signaling and Systems Biology, Max Planck Institute for Experimental Medicine, Goettingen, Germany
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86
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Abstract
Selective enrichment of the polyphosphoinositides (PPIn), such as PtdIns(4,5)P2 and PtdIns4P, helps to determine the identity of the plasma membrane (PM) and regulates many aspects of cell biology through a vast number of protein effectors. Polarity proteins had long been assumed to be non-PPIn-binding proteins that mainly associate with PM/cell cortex through their extensive protein-protein interaction network. However, recent studies began to reveal that several key polarity proteins electrostatically bind to PPIn through their positively charged protein domains or structures and such PPIn-binding property is essential for their direct and specific attachment to PM. Although the physical nature of the charge-based PPIn binding appears to be simple and nonspecific, it serves as an elegant mechanism that can be efficiently and specifically regulated for achieving polarized PM targeting of polarity proteins. As an unexpected consequence, subcellular localization of PPIn-binding polarity proteins are also subject to regulations by physiological conditions such as hypoxia and ischemia that acutely and reversibly depletes PPIn from PM.
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Affiliation(s)
- Gerald R Hammond
- Department of Cell Biology, University of Pittsburgh Medical School, Pittsburgh, Pennsylvania 15261
| | - Yang Hong
- Department of Cell Biology, University of Pittsburgh Medical School, Pittsburgh, Pennsylvania 15261
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87
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Al-Ramahi I, Giridharan SSP, Chen YC, Patnaik S, Safren N, Hasegawa J, de Haro M, Wagner Gee AK, Titus SA, Jeong H, Clarke J, Krainc D, Zheng W, Irvine RF, Barmada S, Ferrer M, Southall N, Weisman LS, Botas J, Marugan JJ. Inhibition of PIP4Kγ ameliorates the pathological effects of mutant huntingtin protein. eLife 2017; 6:29123. [PMID: 29256861 PMCID: PMC5743427 DOI: 10.7554/elife.29123] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Accepted: 11/13/2017] [Indexed: 12/15/2022] Open
Abstract
The discovery of the causative gene for Huntington’s disease (HD) has promoted numerous efforts to uncover cellular pathways that lower levels of mutant huntingtin protein (mHtt) and potentially forestall the appearance of HD-related neurological defects. Using a cell-based model of pathogenic huntingtin expression, we identified a class of compounds that protect cells through selective inhibition of a lipid kinase, PIP4Kγ. Pharmacological inhibition or knock-down of PIP4Kγ modulates the equilibrium between phosphatidylinositide (PI) species within the cell and increases basal autophagy, reducing the total amount of mHtt protein in human patient fibroblasts and aggregates in neurons. In two Drosophila models of Huntington’s disease, genetic knockdown of PIP4K ameliorated neuronal dysfunction and degeneration as assessed using motor performance and retinal degeneration assays respectively. Together, these results suggest that PIP4Kγ is a druggable target whose inhibition enhances productive autophagy and mHtt proteolysis, revealing a useful pharmacological point of intervention for the treatment of Huntington’s disease, and potentially for other neurodegenerative disorders.
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Affiliation(s)
- Ismael Al-Ramahi
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, United States.,Baylor College of Medicine, Texas Medical Center, Houston, United States
| | | | - Yu-Chi Chen
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences, Rockville, United States
| | - Samarjit Patnaik
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences, Rockville, United States
| | - Nathaniel Safren
- Department of Neurology, University of Michigan, Ann Arbor, United States
| | - Junya Hasegawa
- Department of Cell and Developmental Biology, Life Sciences Institute, University of Michigan, Ann Arbor, United States
| | - Maria de Haro
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, United States.,Baylor College of Medicine, Texas Medical Center, Houston, United States
| | - Amanda K Wagner Gee
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences, Rockville, United States
| | - Steven A Titus
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences, Rockville, United States
| | - Hyunkyung Jeong
- The Ken and Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - Jonathan Clarke
- Department of Pharmacology, University of Cambridge, Cambridge, United Kingdom
| | - Dimitri Krainc
- The Ken and Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - Wei Zheng
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences, Rockville, United States
| | - Robin F Irvine
- Department of Pharmacology, University of Cambridge, Cambridge, United Kingdom
| | - Sami Barmada
- Department of Neurology, University of Michigan, Ann Arbor, United States
| | - Marc Ferrer
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences, Rockville, United States
| | - Noel Southall
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences, Rockville, United States
| | - Lois S Weisman
- Department of Cell and Developmental Biology, Life Sciences Institute, University of Michigan, Ann Arbor, United States
| | - Juan Botas
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, United States.,Baylor College of Medicine, Texas Medical Center, Houston, United States
| | - Juan Jose Marugan
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences, Rockville, United States
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88
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Abstract
Hammond previews work by Naufer et al. that uncovers an intriguing link between lysosome acidification and lipid landmarks. How do organelles coordinate their unique molecular identities between their cytosolic-facing surface membranes and their interior? In this issue, Naufer et al. (2017. J. Cell Biol.https://doi.org/10.1083/jcb.201702179) discover an intriguing link between phagosome acidification and lipid signposts on their outer membrane.
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Affiliation(s)
- Gerald R V Hammond
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA
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89
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Ebrahimzadeh Z, Mukherjee A, Richard D. A map of the subcellular distribution of phosphoinositides in the erythrocytic cycle of the malaria parasite Plasmodium falciparum. Int J Parasitol 2017; 48:13-25. [PMID: 29154995 DOI: 10.1016/j.ijpara.2017.08.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Revised: 08/22/2017] [Accepted: 08/31/2017] [Indexed: 12/16/2022]
Abstract
Despite representing a small percentage of the cellular lipids of eukaryotic cells, phosphoinositides (PIPs) are critical in various processes such as intracellular trafficking and signal transduction. Central to their various functions is the differential distribution of PIP species to specific membrane compartments through the actions of kinases, phosphatases and lipases. Despite their importance in the malaria parasite lifecycle, the subcellular distribution of most PIP species in this organism is still unknown. We here localise several species of PIPs throughout the erythrocytic cycle of Plasmodium falciparum. We show that PI3P is mostly found at the apicoplast and the membrane of the food vacuole, that PI4P associates with the Golgi apparatus and the plasma membrane and that PI(4,5)P2, in addition to being detected at the plasma membrane, labels some cavity-like spherical structures. Finally, we show that the elusive PI5P localises to the plasma membrane, the nucleus and potentially to the transitional endoplasmic reticulum (ER). Our map of the subcellular distribution of PIP species in P. falciparum will be a useful tool to shed light on the dynamics of these lipids in this deadly parasite.
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Affiliation(s)
- Zeinab Ebrahimzadeh
- Centre de recherche en infectiologie, CRCHU de Québec-Université Laval, 2705 Boul. Laurier, Québec, QC G1V 4G2, Canada
| | - Angana Mukherjee
- Centre de recherche en infectiologie, CRCHU de Québec-Université Laval, 2705 Boul. Laurier, Québec, QC G1V 4G2, Canada
| | - Dave Richard
- Centre de recherche en infectiologie, CRCHU de Québec-Université Laval, 2705 Boul. Laurier, Québec, QC G1V 4G2, Canada.
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90
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Naufer A, Hipolito VEB, Ganesan S, Prashar A, Zaremberg V, Botelho RJ, Terebiznik MR. pH of endophagosomes controls association of their membranes with Vps34 and PtdIns(3)P levels. J Cell Biol 2017; 217:329-346. [PMID: 29089378 PMCID: PMC5748975 DOI: 10.1083/jcb.201702179] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Revised: 09/03/2017] [Accepted: 09/26/2017] [Indexed: 12/19/2022] Open
Abstract
Specific changes in phospholipid content are a hallmark of the membranes of maturing endosomes and phagosomes, but is it unclear how this is controlled. Naufer et al. now show that acidification of the lumen of endosomes and phagosomes triggers dissociation of the Vps34 lipid kinase from these organelles, which terminates PtdIns(3)P synthesis and signaling. Phagocytosis of filamentous bacteria occurs through tubular phagocytic cups (tPCs) and takes many minutes to engulf these filaments into phagosomes. Contravening the canonical phagocytic pathway, tPCs mature by fusing with endosomes. Using this model, we observed the sequential recruitment of early and late endolysosomal markers to the elongating tPCs. Surprisingly, the regulatory early endosomal lipid phosphatidylinositol-3-phosphate (PtdIns(3)P) persists on tPCs as long as their luminal pH remains neutral. Interestingly, by manipulating cellular pH, we determined that PtdIns(3)P behaves similarly in canonical phagosomes as well as endosomes. We found that this is the product of a pH-based mechanism that induces the dissociation of the Vps34 class III phosphatidylinositol-3-kinase from these organelles as they acidify. The detachment of Vps34 stops the production of PtdIns(3)P, allowing for the turnover of this lipid by PIKfyve. Given that PtdIns(3)P-dependent signaling is important for multiple cellular pathways, this mechanism for pH-dependent regulation of Vps34 could be at the center of many PtdIns(3)P-dependent cellular processes.
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Affiliation(s)
- Amriya Naufer
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, Canada.,Department of Cell and System Biology, University of Toronto Scarborough, Toronto, Canada
| | - Victoria E B Hipolito
- Molecular Science Graduate Program, Ryerson University, Toronto, Canada.,Department of Chemistry and Biology, Ryerson University, Toronto, Canada
| | | | - Akriti Prashar
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, Canada.,Department of Cell and System Biology, University of Toronto Scarborough, Toronto, Canada
| | - Vanina Zaremberg
- Department of Biological Sciences, University of Calgary, Calgary, Canada
| | - Roberto J Botelho
- Molecular Science Graduate Program, Ryerson University, Toronto, Canada .,Department of Chemistry and Biology, Ryerson University, Toronto, Canada
| | - Mauricio R Terebiznik
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, Canada .,Department of Cell and System Biology, University of Toronto Scarborough, Toronto, Canada
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91
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Notomi T, Kuno M, Hiyama A, Nozaki T, Ohura K, Ezura Y, Noda M. Role of lysosomal channel protein TPC2 in osteoclast differentiation and bone remodeling under normal and low-magnesium conditions. J Biol Chem 2017; 292:20998-21010. [PMID: 29084844 DOI: 10.1074/jbc.m117.780072] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Revised: 09/25/2017] [Indexed: 11/06/2022] Open
Abstract
The bone is the main storage site for Ca2+ and Mg2+ ions in the mammalian body. Although investigations into Ca2+ signaling have progressed rapidly and led to better understanding of bone biology, the Mg2+ signaling pathway and associated molecules remain to be elucidated. Here, we investigated the role of a potential Mg2+ signaling-related lysosomal molecule, two-pore channel subtype 2 (TPC2), in osteoclast differentiation and bone remodeling. Previously, we found that under normal Mg2+ conditions, TPC2 promotes osteoclastogenesis. We observed that under low-Mg2+ conditions, TPC2 inhibited, rather than promoted, the osteoclast differentiation and that the phosphatidylinositol 3,5-bisphosphate (PI(3,5)P2) signaling pathway played a role in the TPC2 activation under low-Mg2+ conditions. Furthermore, PI(3,5)P2 depolarized the membrane potential by increasing the intracellular Na+ levels. To investigate how membrane depolarization affects osteoclast differentiation, we generated a light-sensitive cell line and developed a system for the light-stimulated depolarization of the membrane potential. The light-induced depolarization inhibited the osteoclast differentiation. We then tested the effect of myo-inositol supplementation, which increased the PI(3,5)P2 levels in mice fed a low-Mg2+ diet. The myo-inositol supplementation rescued the low-Mg2+ diet-induced trabecular bone loss, which was accompanied by the inhibition of osteoclastogenesis. These results indicate that low-Mg2+-induced osteoclastogenesis involves changes in the role of TPC2, which are mediated through the PI(3,5)P2 pathway. Our findings also suggest that myo-inositol consumption might provide beneficial effects in Mg2+ deficiency-induced skeletal diseases.
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Affiliation(s)
- Takuya Notomi
- From the Department of Molecular Pharmacology, Medical Research Institute and .,the Global Center of Excellence Program for Molecular Science for Tooth and Bone Diseases, Tokyo Medical and Dental University, Bunkyo 113-8510, Tokyo, Japan.,the Department of Pharmacology, Osaka Dental University, Hirakata, Osaka 573-1121, Japan
| | - Miyuki Kuno
- the Department of Physiology, Graduate School of Medicine, Osaka City University, Abeno, Osaka 545-8585, Japan, and
| | - Akiko Hiyama
- the Department of Pharmacology, Osaka Dental University, Hirakata, Osaka 573-1121, Japan
| | - Tadashige Nozaki
- the Department of Pharmacology, Osaka Dental University, Hirakata, Osaka 573-1121, Japan
| | - Kiyoshi Ohura
- the Department of Pharmacology, Osaka Dental University, Hirakata, Osaka 573-1121, Japan
| | - Yoichi Ezura
- From the Department of Molecular Pharmacology, Medical Research Institute and
| | - Masaki Noda
- From the Department of Molecular Pharmacology, Medical Research Institute and .,the Global Center of Excellence Program for Molecular Science for Tooth and Bone Diseases, Tokyo Medical and Dental University, Bunkyo 113-8510, Tokyo, Japan.,the Yokohama City Minato Red Cross Hospital, Yokohama, Kanagawa 231-8682, Japan
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92
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Bissig C, Hurbain I, Raposo G, van Niel G. PIKfyve activity regulates reformation of terminal storage lysosomes from endolysosomes. Traffic 2017; 18:747-757. [DOI: 10.1111/tra.12525] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Revised: 08/25/2017] [Accepted: 08/25/2017] [Indexed: 12/21/2022]
Affiliation(s)
- Christin Bissig
- Institut Curie; PSL Research University, CNRS, UMR144; Paris France
- Sorbonne Universités; UPMC Univ Paris 06, CNRS, UMR 144; Paris France
| | - Ilse Hurbain
- Institut Curie; PSL Research University, CNRS, UMR144; Paris France
- Sorbonne Universités; UPMC Univ Paris 06, CNRS, UMR 144; Paris France
- Cell and Tissue Imaging Core Facility PICT-IBiSA; Institut Curie; Paris France
| | - Graça Raposo
- Institut Curie; PSL Research University, CNRS, UMR144; Paris France
- Sorbonne Universités; UPMC Univ Paris 06, CNRS, UMR 144; Paris France
- Cell and Tissue Imaging Core Facility PICT-IBiSA; Institut Curie; Paris France
| | - Guillaume van Niel
- Institut Curie; PSL Research University, CNRS, UMR144; Paris France
- Sorbonne Universités; UPMC Univ Paris 06, CNRS, UMR 144; Paris France
- Cell and Tissue Imaging Core Facility PICT-IBiSA; Institut Curie; Paris France
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93
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Dayam RM, Sun CX, Choy CH, Mancuso G, Glogauer M, Botelho RJ. The Lipid Kinase PIKfyve Coordinates the Neutrophil Immune Response through the Activation of the Rac GTPase. THE JOURNAL OF IMMUNOLOGY 2017; 199:2096-2105. [DOI: 10.4049/jimmunol.1601466] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Accepted: 07/11/2017] [Indexed: 11/19/2022]
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94
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Banerjee S, Kane PM. Direct interaction of the Golgi V-ATPase a-subunit isoform with PI(4)P drives localization of Golgi V-ATPases in yeast. Mol Biol Cell 2017; 28:2518-2530. [PMID: 28720663 PMCID: PMC5597324 DOI: 10.1091/mbc.e17-05-0316] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Revised: 07/03/2017] [Accepted: 07/14/2017] [Indexed: 12/11/2022] Open
Abstract
PI(4)P directly interacts with the cytosolic domain of yeast Golgi vacuolar H+-ATPase (V-ATPase) a-isoform, Stv1, and the human Golgi a-subunit isoform. Lys-84 of Stv1 is essential for PI(4)P interaction, and localization of Stv1-containing V-ATPases in vivo requires the PI(4)P interaction. We propose that phosphatidylinositol binding exerts organelle-specific control over V-ATPases. Luminal pH and phosphoinositide content are fundamental features of organelle identity. Vacuolar H+-ATPases (V-ATPases) drive organelle acidification in all eukaryotes, and membrane-bound a-subunit isoforms of the V-ATPase are implicated in organelle-specific targeting and regulation. Earlier work demonstrated that the endolysosomal lipid PI(3,5)P2 activates V-ATPases containing the vacuolar a-subunit isoform in Saccharomyces cerevisiae. Here we demonstrate that PI(4)P, the predominant Golgi phosphatidylinositol (PI) species, directly interacts with the cytosolic amino terminal (NT) domain of the yeast Golgi V-ATPase a-isoform Stv1. Lysine-84 of Stv1NT is essential for interaction with PI(4)P in vitro and in vivo, and interaction with PI(4)P is required for efficient localization of Stv1-containing V-ATPases. The cytosolic NT domain of the human V-ATPase a2 isoform specifically interacts with PI(4)P in vitro, consistent with its Golgi localization and function. We propose that NT domains of Vo a-subunit isoforms interact specifically with PI lipids in their organelles of residence. These interactions can transmit organelle-specific targeting or regulation information to V-ATPases.
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Affiliation(s)
- Subhrajit Banerjee
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY 13210
| | - Patricia M Kane
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY 13210
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95
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Di Paola S, Scotto-Rosato A, Medina DL. TRPML1: The Ca (2+)retaker of the lysosome. Cell Calcium 2017; 69:112-121. [PMID: 28689729 DOI: 10.1016/j.ceca.2017.06.006] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Revised: 06/16/2017] [Accepted: 06/16/2017] [Indexed: 12/27/2022]
Abstract
Efficient functioning of lysosome is necessary to ensure the correct performance of a variety of intracellular processes such as degradation of cargoes coming from the endocytic and autophagic pathways, recycling of organelles, and signaling mechanisms involved in cellular adaptation to nutrient availability. Mutations in lysosomal genes lead to more than 50 lysosomal storage disorders (LSDs). Among them, mutations in the gene encoding TRPML1 (MCOLN1) cause Mucolipidosis type IV (MLIV), a recessive LSD characterized by neurodegeneration, psychomotor retardation, ophthalmologic defects and achlorhydria. At the cellular level, MLIV patient fibroblasts show enlargement and engulfment of the late endo-lysosomal compartment, autophagy impairment, and accumulation of lipids and glycosaminoglycans. TRPML1 is the most extensively studied member of a small family of genes that also includes TRPML2 and TRPML3, and it has been found to participate in vesicular trafficking, lipid and ion homeostasis, and autophagy. In this review we will provide an update on the latest and more novel findings related to the functions of TRPMLs, with particular focus on the emerging role of TRPML1 and lysosomal calcium signaling in autophagy. Moreover, we will also discuss new potential therapeutic approaches for MLIV and LSDs based on the modulation of TRPML1-mediated signaling.
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Affiliation(s)
- Simone Di Paola
- Telethon Institute of Genetics and Medicine (TIGEM), Via Campi Flegrei 34, 80078 Pozzuoli ,NA, Italy
| | - Anna Scotto-Rosato
- Telethon Institute of Genetics and Medicine (TIGEM), Via Campi Flegrei 34, 80078 Pozzuoli ,NA, Italy
| | - Diego Luis Medina
- Telethon Institute of Genetics and Medicine (TIGEM), Via Campi Flegrei 34, 80078 Pozzuoli ,NA, Italy.
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96
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Jin N, Jin Y, Weisman LS. Early protection to stress mediated by CDK-dependent PI3,5P 2 signaling from the vacuole/lysosome. J Cell Biol 2017. [PMID: 28637746 PMCID: PMC5496620 DOI: 10.1083/jcb.201611144] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Adaptation to stress is a critical strategy for all life. Known strategies involve signaling pathways that induce changes in gene expression. These changes take time and cannot protect against acute assaults. Jin et al. reveal an early stress protection pathway regulated by the vacuole/lysosome. Adaptation to environmental stress is critical for cell survival. Adaptation generally occurs via changes in transcription and translation. However, there is a time lag before changes in gene expression, which suggests that more rapid mechanisms likely exist. In this study, we show that in yeast, the cyclin-dependent kinase Pho85/CDK5 provides protection against hyperosmotic stress and acts before long-term adaptation provided by Hog1. This protection requires the vacuolar/endolysosomal signaling lipid PI3,5P2. We show that Pho85/CDK5 directly phosphorylates and positively regulates the PI3P-5 kinase Fab1/PIKfyve complex and provide evidence that this regulation is conserved in mammalian cells. Moreover, this regulation is particularly crucial in yeast for the stress-induced transient elevation of PI3,5P2. Our study reveals a rapid protection mechanism regulated by Pho85/CDK5 via signaling from the vacuole/lysosome, which is distinct temporally and spatially from the previously discovered long-term adaptation Hog1 pathway, which signals from the nucleus.
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Affiliation(s)
- Natsuko Jin
- Life Sciences Institute, University of Michigan, Ann Arbor, MI
| | - Yui Jin
- Life Sciences Institute, University of Michigan, Ann Arbor, MI
| | - Lois S Weisman
- Life Sciences Institute, University of Michigan, Ann Arbor, MI .,Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI
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97
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Schulze U, Vollenbröker B, Kühnl A, Granado D, Bayraktar S, Rescher U, Pavenstädt H, Weide T. Cellular vacuolization caused by overexpression of the PIKfyve-binding deficient Vac14L156R is rescued by starvation and inhibition of vacuolar-ATPase. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2017; 1864:749-759. [DOI: 10.1016/j.bbamcr.2017.02.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Revised: 02/09/2017] [Accepted: 02/15/2017] [Indexed: 12/28/2022]
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98
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Song ES, Jang H, Guo HF, Juliano MA, Juliano L, Morris AJ, Galperin E, Rodgers DW, Hersh LB. Inositol phosphates and phosphoinositides activate insulin-degrading enzyme, while phosphoinositides also mediate binding to endosomes. Proc Natl Acad Sci U S A 2017; 114:E2826-E2835. [PMID: 28325868 PMCID: PMC5389272 DOI: 10.1073/pnas.1613447114] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Insulin-degrading enzyme (IDE) hydrolyzes bioactive peptides, including insulin, amylin, and the amyloid β peptides. Polyanions activate IDE toward some substrates, yet an endogenous polyanion activator has not yet been identified. Here we report that inositol phosphates (InsPs) and phosphatdidylinositol phosphates (PtdInsPs) serve as activators of IDE. InsPs and PtdInsPs interact with the polyanion-binding site located on an inner chamber wall of the enzyme. InsPs activate IDE by up to ∼95-fold, affecting primarily Vmax The extent of activation and binding affinity correlate with the number of phosphate groups on the inositol ring, with phosphate positional effects observed. IDE binds PtdInsPs from solution, immobilized on membranes, or presented in liposomes. Interaction with PtdInsPs, likely PtdIns(3)P, plays a role in localizing IDE to endosomes, where the enzyme reportedly encounters physiological substrates. Thus, InsPs and PtdInsPs can serve as endogenous modulators of IDE activity, as well as regulators of its intracellular spatial distribution.
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Affiliation(s)
- Eun Suk Song
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY 40536
| | - HyeIn Jang
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY 40536
| | - Hou-Fu Guo
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY 40536
| | - Maria A Juliano
- Department of Biophysics, Escola Paulista de Medicina, Universidade Federal de Sao Paulo, 04044-020 Sao Paulo, Brazil
| | - Luiz Juliano
- Department of Biophysics, Escola Paulista de Medicina, Universidade Federal de Sao Paulo, 04044-020 Sao Paulo, Brazil
| | - Andrew J Morris
- Division of Cardiovascular Medicine, University of Kentucky College of Medicine, Lexington, KY 40536
| | - Emilia Galperin
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY 40536
| | - David W Rodgers
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY 40536;
- Center for Structural Biology, University of Kentucky, Lexington, KY 40536
| | - Louis B Hersh
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY 40536;
- Center for Structural Biology, University of Kentucky, Lexington, KY 40536
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99
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Gilden JK, Umaer K, Kruzel EK, Hecht O, Correa RO, Mansfield JM, Bangs JD. The role of the PI(3,5)P 2 kinase TbFab1 in endo/lysosomal trafficking in Trypanosoma brucei. Mol Biochem Parasitol 2017; 214:52-61. [PMID: 28356223 DOI: 10.1016/j.molbiopara.2017.03.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2017] [Revised: 03/22/2017] [Accepted: 03/23/2017] [Indexed: 12/01/2022]
Abstract
Protein trafficking through endo/lysosomal compartments is critically important to the biology of the protozoan parasite Trypanosoma brucei, but the routes material may take to the lysosome, as well as the molecular factors regulating those routes, remain incompletely understood. Phosphoinositides are signaling phospholipids that regulate many trafficking events by recruiting specific effector proteins to discrete membrane subdomains. In this study, we investigate the role of one phosphoinositide, PI(3,5)P2 in T. brucei. We find a low steady state level of PI(3,5)P2 in bloodstream form parasites comparable to that of other organisms. RNAi knockdown of the putative PI(3)P-5 kinase TbFab1 decreases the PI(3,5)P2 pool leading to rapid cell death. TbFab1 and PI(3,5)P2 both localize strongly to late endo/lysosomes. While most trafficking functions were intact in TbFab1 deficient cells, including both endocytic and biosynthetic trafficking to the lysosome, lysosomal turnover of an endogenous ubiquitinylated membrane protein, ISG65, was completely blocked suggesting that TbFab1 plays a role in the ESCRT-mediated late endosomal/multivesicular body degradative pathways. Knockdown of a second component of PI(3,5)P2 metabolism, the PI(3,5)P2 phosphatase TbFig4, also resulted in delayed turnover of ISG65. Together, these results demonstrate an essential role for PI(3,5)P2 in the turnover of ubiquitinylated membrane proteins and in trypanosome endomembrane biology.
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Affiliation(s)
- Julia K Gilden
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, USA.
| | - Khan Umaer
- Department of Microbiology Immunology, School of Medicine and Biomedical Sciences, University at Buffalo (SUNY), Buffalo, NY, USA.
| | - Emilia K Kruzel
- Department of Microbiology Immunology, School of Medicine and Biomedical Sciences, University at Buffalo (SUNY), Buffalo, NY, USA.
| | - Oliver Hecht
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, USA.
| | - Renan O Correa
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, USA.
| | - John M Mansfield
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, USA.
| | - James D Bangs
- Department of Microbiology Immunology, School of Medicine and Biomedical Sciences, University at Buffalo (SUNY), Buffalo, NY, USA.
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100
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Hasegawa J, Strunk BS, Weisman LS. PI5P and PI(3,5)P 2: Minor, but Essential Phosphoinositides. Cell Struct Funct 2017; 42:49-60. [PMID: 28302928 DOI: 10.1247/csf.17003] [Citation(s) in RCA: 95] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
In most eukaryotes, phosphoinositides (PIs) have crucial roles in multiple cellular functions. Although the cellular levels of phosphatidylinositol 5-phosphate (PI5P) and phosphatidylinositol 3,5-bisphosphate (PI(3,5)P2) are extremely low relative to some other PIs, emerging evidence demonstrates that both lipids are crucial for the endocytic pathway, intracellular signaling, and adaptation to stress. Mutations that causes defects in the biosynthesis of PI5P and PI(3,5)P2 are linked to human diseases including neurodegenerative disorders. Here, we review recent findings on cellular roles of PI5P and PI(3,5)P2, as well as the pathophysiological importance of these lipids.Key words: Phosphoinositides, Membrane trafficking, Endocytosis, Vacuoles/Lysosomes, Fab1/PIKfyve.
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