1
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Li S, Han T. Frequent loss of FAM126A expression in colorectal cancer results in selective FAM126B dependency. iScience 2024; 27:109646. [PMID: 38638566 PMCID: PMC11025007 DOI: 10.1016/j.isci.2024.109646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2023] [Revised: 11/01/2023] [Accepted: 03/27/2024] [Indexed: 04/20/2024] Open
Abstract
Most advanced colorectal cancer (CRC) patients cannot benefit from targeted therapy due to lack of actionable targets. By mining data from the DepMap, we identified FAM126B as a specific vulnerability in CRC cell lines exhibiting low FAM126A expression. Employing a combination of genetic perturbation and inducible protein degradation techniques, we demonstrate that FAM126A and FAM126B function in a redundant manner to facilitate the recruitment of PI4KIIIα to the plasma membrane for PI4P synthesis. Examination of data from TCGA and GTEx revealed that over 7% of CRC tumor samples exhibited loss of FAM126A expression, contrasting with uniform FAM126A expression in normal tissues. In both CRC cell lines and tumor samples, promoter hypermethylation correlated with the loss of FAM126A expression, which could be reversed by DNA methylation inhibitors. In conclusion, our study reveals that loss of FAM126A expression results in FAM126B dependency, thus proposing FAM126B as a therapeutic target for CRC treatment.
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Affiliation(s)
- Shuang Li
- PTN Joint Graduate Program, School of Life Sciences, Peking University, Beijing 100871, China
- National Institute of Biological Sciences, Beijing 102206, China
| | - Ting Han
- PTN Joint Graduate Program, School of Life Sciences, Peking University, Beijing 100871, China
- National Institute of Biological Sciences, Beijing 102206, China
- Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing 102206, China
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2
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Krantz M, Eklund D, Särndahl E, Hedbrant A. A detailed molecular network map and model of the NLRP3 inflammasome. Front Immunol 2023; 14:1233680. [PMID: 38077364 PMCID: PMC10699087 DOI: 10.3389/fimmu.2023.1233680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Accepted: 10/16/2023] [Indexed: 12/18/2023] Open
Abstract
The NLRP3 inflammasome is a key regulator of inflammation that responds to a broad range of stimuli. The exact mechanism of activation has not been determined, but there is a consensus on cellular potassium efflux as a major common denominator. Once NLRP3 is activated, it forms high-order complexes together with NEK7 that trigger aggregation of ASC into specks. Typically, there is only one speck per cell, consistent with the proposal that specks form - or end up at - the centrosome. ASC polymerisation in turn triggers caspase-1 activation, leading to maturation and release of IL-1β and pyroptosis, i.e., highly inflammatory cell death. Several gain-of-function mutations in the NLRP3 inflammasome have been suggested to induce spontaneous activation of NLRP3 and hence contribute to development and disease severity in numerous autoinflammatory and autoimmune diseases. Consequently, the NLRP3 inflammasome is of significant clinical interest, and recent attention has drastically improved our insight in the range of involved triggers and mechanisms of signal transduction. However, despite recent progress in knowledge, a clear and comprehensive overview of how these mechanisms interplay to shape the system level function is missing from the literature. Here, we provide such an overview as a resource to researchers working in or entering the field, as well as a computational model that allows for evaluating and explaining the function of the NLRP3 inflammasome system from the current molecular knowledge. We present a detailed reconstruction of the molecular network surrounding the NLRP3 inflammasome, which account for each specific reaction and the known regulatory constraints on each event as well as the mechanisms of drug action and impact of genetics when known. Furthermore, an executable model from this network reconstruction is generated with the aim to be used to explain NLRP3 activation from priming and activation to the maturation and release of IL-1β and IL-18. Finally, we test this detailed mechanistic model against data on the effect of different modes of inhibition of NLRP3 assembly. While the exact mechanisms of NLRP3 activation remains elusive, the literature indicates that the different stimuli converge on a single activation mechanism that is additionally controlled by distinct (positive or negative) priming and licensing events through covalent modifications of the NLRP3 molecule. Taken together, we present a compilation of the literature knowledge on the molecular mechanisms on NLRP3 activation, a detailed mechanistic model of NLRP3 activation, and explore the convergence of diverse NLRP3 activation stimuli into a single input mechanism.
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Affiliation(s)
- Marcus Krantz
- School of Medical Sciences, Faculty of Medicine and Health, Örebro University, Örebro, Sweden
- Inflammatory Response and Infection Susceptibility Centre (iRiSC), Örebro University, Örebro, Sweden
| | - Daniel Eklund
- School of Medical Sciences, Faculty of Medicine and Health, Örebro University, Örebro, Sweden
- Inflammatory Response and Infection Susceptibility Centre (iRiSC), Örebro University, Örebro, Sweden
| | - Eva Särndahl
- School of Medical Sciences, Faculty of Medicine and Health, Örebro University, Örebro, Sweden
- Inflammatory Response and Infection Susceptibility Centre (iRiSC), Örebro University, Örebro, Sweden
| | - Alexander Hedbrant
- School of Medical Sciences, Faculty of Medicine and Health, Örebro University, Örebro, Sweden
- Inflammatory Response and Infection Susceptibility Centre (iRiSC), Örebro University, Örebro, Sweden
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3
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Criado Santos N, Bouvet S, Cruz Cobo M, Mandavit M, Bermont F, Castelbou C, Mansour F, Azam M, Giordano F, Nunes-Hasler P. Sec22b regulates phagosome maturation by promoting ORP8-mediated lipid exchange at endoplasmic reticulum-phagosome contact sites. Commun Biol 2023; 6:1008. [PMID: 37794132 PMCID: PMC10550925 DOI: 10.1038/s42003-023-05382-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Accepted: 09/21/2023] [Indexed: 10/06/2023] Open
Abstract
Phagosome maturation is critical for immune defense, defining whether ingested material is destroyed or converted into antigens. Sec22b regulates phagosome maturation, yet how has remained unclear. Here we show Sec22b tethers endoplasmic reticulum-phagosome membrane contact sites (MCS) independently of the known tether STIM1. Sec22b knockdown increases calcium signaling, phagolysosome fusion and antigen degradation and alters phagosomal phospholipids PI(3)P, PS and PI(4)P. Levels of PI(4)P, a lysosome docking lipid, are rescued by Sec22b re-expression and by expression of the artificial tether MAPPER but not the MCS-disrupting mutant Sec22b-P33. Moreover, Sec22b co-precipitates with the PS/PI(4)P exchange protein ORP8. Wild-type, but not mutant ORP8 rescues phagosomal PI(4)P and reduces antigen degradation. Sec22b, MAPPER and ORP8 but not P33 or mutant-ORP8 restores phagolysosome fusion in knockdown cells. These findings clarify an alternative mechanism through which Sec22b controls phagosome maturation and beg a reassessment of the relative contribution of Sec22b-mediated fusion versus tethering to phagosome biology.
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Affiliation(s)
- Nina Criado Santos
- Department of Pathology and Immunology, Geneva Center for Inflammation Research, Faculty of Medicine, University of Geneva, Centre Médicale Universitaire, 1 Rue Michel-Servet, Geneva, Switzerland
| | - Samuel Bouvet
- Department of Cellular Physiology and Metabolism, Faculty of Medicine, University of Geneva, Centre Médicale Universitaire, 1 Rue Michel-Servet, Geneva, Switzerland
| | - Maria Cruz Cobo
- Department of Pathology and Immunology, Geneva Center for Inflammation Research, Faculty of Medicine, University of Geneva, Centre Médicale Universitaire, 1 Rue Michel-Servet, Geneva, Switzerland
| | - Marion Mandavit
- Department of Pathology and Immunology, Geneva Center for Inflammation Research, Faculty of Medicine, University of Geneva, Centre Médicale Universitaire, 1 Rue Michel-Servet, Geneva, Switzerland
| | - Flavien Bermont
- Department of Cellular Physiology and Metabolism, Faculty of Medicine, University of Geneva, Centre Médicale Universitaire, 1 Rue Michel-Servet, Geneva, Switzerland
| | - Cyril Castelbou
- Department of Cellular Physiology and Metabolism, Faculty of Medicine, University of Geneva, Centre Médicale Universitaire, 1 Rue Michel-Servet, Geneva, Switzerland
| | - Farah Mansour
- Department of Pathology and Immunology, Geneva Center for Inflammation Research, Faculty of Medicine, University of Geneva, Centre Médicale Universitaire, 1 Rue Michel-Servet, Geneva, Switzerland
| | - Maral Azam
- Department of Pathology and Immunology, Geneva Center for Inflammation Research, Faculty of Medicine, University of Geneva, Centre Médicale Universitaire, 1 Rue Michel-Servet, Geneva, Switzerland
| | - Francesca Giordano
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Saclay, Gif-sur-Yvette cedex, 91198, France
- Inserm U1280, Gif-sur-Yvette cedex, 91198, France
| | - Paula Nunes-Hasler
- Department of Pathology and Immunology, Geneva Center for Inflammation Research, Faculty of Medicine, University of Geneva, Centre Médicale Universitaire, 1 Rue Michel-Servet, Geneva, Switzerland.
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4
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Boutry M, DiGiovanni LF, Demers N, Fountain A, Mamand S, Botelho RJ, Kim PK. Arf1-PI4KIIIβ positive vesicles regulate PI(3)P signaling to facilitate lysosomal tubule fission. J Cell Biol 2023; 222:e202205128. [PMID: 37289133 PMCID: PMC10250553 DOI: 10.1083/jcb.202205128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 04/03/2023] [Accepted: 05/22/2023] [Indexed: 06/09/2023] Open
Abstract
Formation and fission of tubules from autolysosomes, endolysosomes, or phagolysosomes are required for lysosome reformation. However, the mechanisms governing these processes in these different lysosomal organelles are poorly understood. Thus, the role of phosphatidylinositol-4-phosphate (PI(4)P) is unclear as it was shown to promote the formation of tubules from phagolysosomes but was proposed to inhibit tubule formation on autolysosomes because the loss of PI4KIIIβ causes extensive lysosomal tubulation. Using super-resolution live-cell imaging, we show that Arf1-PI4KIIIβ positive vesicles are recruited to tubule fission sites from autolysosomes, endolysosomes, and phagolysosomes. Moreover, we show that PI(4)P is required to form autolysosomal tubules and that increased lysosomal tubulation caused by loss of PI4KIIIβ represents impaired tubule fission. At the site of fission, we propose that Arf1-PI4KIIIβ positive vesicles mediate a PI(3)P signal on lysosomes in a process requiring the lipid transfer protein SEC14L2. Our findings indicate that Arf1-PI4KIIIβ positive vesicles and their regulation of PI(3)P are critical components of the lysosomal tubule fission machinery.
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Affiliation(s)
- Maxime Boutry
- Cell Biology Program, Hospital for Sick Children, Peter Gilgan Centre for Research and Learning, Toronto, Ontario, Canada
| | - Laura F. DiGiovanni
- Cell Biology Program, Hospital for Sick Children, Peter Gilgan Centre for Research and Learning, Toronto, Ontario, Canada
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Nicholas Demers
- Cell Biology Program, Hospital for Sick Children, Peter Gilgan Centre for Research and Learning, Toronto, Ontario, Canada
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Aaron Fountain
- Department of Chemistry and Biology, Toronto Metropolitan University, Toronto, Ontario, Canada
- Graduate Program in Molecular Science, Toronto Metropolitan University, Toronto, Ontario, Canada
| | - Sami Mamand
- Department of Chemistry and Biology, Toronto Metropolitan University, Toronto, Ontario, Canada
- Graduate Program in Molecular Science, Toronto Metropolitan University, Toronto, Ontario, Canada
- Polytechnic Research Center, Erbil Polytechnic University, Erbil, Kurdistan, Iraq
| | - Roberto J. Botelho
- Department of Chemistry and Biology, Toronto Metropolitan University, Toronto, Ontario, Canada
- Graduate Program in Molecular Science, Toronto Metropolitan University, Toronto, Ontario, Canada
| | - Peter K. Kim
- Cell Biology Program, Hospital for Sick Children, Peter Gilgan Centre for Research and Learning, Toronto, Ontario, Canada
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
- Department of Biomedical Science and Engineering, Gwangju Institute of Science and Technology, Gwangju, South Korea
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5
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Di Cara F, Savary S, Kovacs WJ, Kim P, Rachubinski RA. The peroxisome: an up-and-coming organelle in immunometabolism. Trends Cell Biol 2023; 33:70-86. [PMID: 35788297 DOI: 10.1016/j.tcb.2022.06.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 05/31/2022] [Accepted: 06/03/2022] [Indexed: 12/27/2022]
Abstract
Peroxisomes are essential metabolic organelles, well known for their roles in the metabolism of complex lipids and reactive ionic species. In the past 10 years, peroxisomes have also been cast as central regulators of immunity. Lipid metabolites of peroxisomes, such as polyunsaturated fatty acids (PUFAs), are precursors for important immune mediators, including leukotrienes (LTs) and resolvins. Peroxisomal redox metabolism modulates cellular immune signaling such as nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) activation. Additionally, peroxisomal β-oxidation and ether lipid synthesis control the development and aspects of the activation of both innate and adaptive immune cells. Finally, peroxisome number and metabolic activity have been linked to inflammatory diseases. These discoveries have opened avenues of investigation aimed at targeting peroxisomes for therapeutic intervention in immune disorders, inflammation, and cancer.
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Affiliation(s)
- Francesca Di Cara
- Dalhousie University, Department of Microbiology and Immunology, Halifax, NS B3K 6R8, Canada.
| | - Stéphane Savary
- Lab. Bio-PeroxIL EA7270, University of Bourgogne Franche-Comté, 6 Bd Gabriel, 21000 Dijon, France
| | - Werner J Kovacs
- Institute of Molecular Health Sciences, Swiss Federal Institute of Technology in Zurich (ETH Zürich), Zurich, Switzerland
| | - Peter Kim
- Cell Biology Program, Hospital for Sick Children, Peter Gilgan Centre for Research and Learning, Toronto, ON, Canada; Department of Biochemistry, University of Toronto, Toronto, ON, Canada; Department of Biomedical Science and Engineering, Gwangju Institute of Science and Technology, Gwangju, South Korea
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6
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Walpole GFW, Pacheco J, Chauhan N, Clark J, Anderson KE, Abbas YM, Brabant-Kirwan D, Montaño-Rendón F, Liu Z, Zhu H, Brumell JH, Deiters A, Stephens LR, Hawkins PT, Hammond GRV, Grinstein S, Fairn GD. Kinase-independent synthesis of 3-phosphorylated phosphoinositides by a phosphotransferase. Nat Cell Biol 2022; 24:708-722. [PMID: 35484249 PMCID: PMC9107517 DOI: 10.1038/s41556-022-00895-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 03/08/2022] [Indexed: 01/10/2023]
Abstract
Despite their low abundance, phosphoinositides play a central role in membrane traffic and signalling. PtdIns(3,4,5)P3 and PtdIns(3,4)P2 are uniquely important, as they promote cell growth, survival and migration. Pathogenic organisms have developed means to subvert phosphoinositide metabolism to promote successful infection and their survival in host organisms. We demonstrate that PtdIns(3,4)P2 is a major product generated in host cells by the effectors of the enteropathogenic bacteria Salmonella and Shigella. Pharmacological, gene silencing and heterologous expression experiments revealed that, remarkably, the biosynthesis of PtdIns(3,4)P2 occurs independently of phosphoinositide 3-kinases. Instead, we found that the Salmonella effector SopB, heretofore believed to be a phosphatase, generates PtdIns(3,4)P2 de novo via a phosphotransferase/phosphoisomerase mechanism. Recombinant SopB is capable of generating PtdIns(3,4,5)P3 and PtdIns(3,4)P2 from PtdIns(4,5)P2 in a cell-free system. Through a remarkable instance of convergent evolution, bacterial effectors acquired the ability to synthesize 3-phosphorylated phosphoinositides by an ATP- and kinase-independent mechanism, thereby subverting host signalling to gain entry and even provoke oncogenic transformation.
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Affiliation(s)
- Glenn F W Walpole
- Division of Cell Biology, Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Jonathan Pacheco
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Neha Chauhan
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto, Ontario, Canada
| | | | | | - Yazan M Abbas
- Molecular Medicine Program, Hospital for Sick Children, Toronto, Ontario, Canada
| | | | - Fernando Montaño-Rendón
- Division of Cell Biology, Hospital for Sick Children, Toronto, Ontario, Canada
- Institute of Medical Sciences, University of Toronto, Toronto, Ontario, Canada
| | - Zetao Liu
- Division of Cell Biology, Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Hongxian Zhu
- Division of Cell Biology, Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - John H Brumell
- Division of Cell Biology, Hospital for Sick Children, Toronto, Ontario, Canada
- Institute of Medical Sciences, University of Toronto, Toronto, Ontario, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Alexander Deiters
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA, USA
| | | | | | - Gerald R V Hammond
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Sergio Grinstein
- Division of Cell Biology, Hospital for Sick Children, Toronto, Ontario, Canada.
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada.
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto, Ontario, Canada.
- Institute of Medical Sciences, University of Toronto, Toronto, Ontario, Canada.
| | - Gregory D Fairn
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada.
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto, Ontario, Canada.
- Institute of Medical Sciences, University of Toronto, Toronto, Ontario, Canada.
- Department of Pathology, Dalhousie University, Halifax, Nova Scotia, Canada.
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7
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Hammond GRV, Ricci MMC, Weckerly CC, Wills RC. An update on genetically encoded lipid biosensors. Mol Biol Cell 2022; 33:tp2. [PMID: 35420888 PMCID: PMC9282013 DOI: 10.1091/mbc.e21-07-0363] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 02/15/2022] [Accepted: 02/16/2022] [Indexed: 01/16/2023] Open
Abstract
Specific lipid species play central roles in cell biology. Their presence or enrichment in individual membranes can control properties or direct protein localization and/or activity. Therefore, probes to detect and observe these lipids in intact cells are essential tools in the cell biologist's freezer box. Herein, we discuss genetically encoded lipid biosensors, which can be expressed as fluorescent protein fusions to track lipids in living cells. We provide a state-of-the-art list of the most widely available and reliable biosensors and highlight new probes (circa 2018-2021). Notably, we focus on advances in biosensors for phosphatidylinositol, phosphatidic acid, and PI 3-kinase lipid products.
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Affiliation(s)
- Gerald R. V. Hammond
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | - Morgan M. C. Ricci
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | - Claire C. Weckerly
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | - Rachel C. Wills
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
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8
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Nath AS, Parsons BD, Makdissi S, Chilvers RL, Mu Y, Weaver CM, Euodia I, Fitze KA, Long J, Scur M, Mackenzie DP, Makrigiannis AP, Pichaud N, Boudreau LH, Simmonds AJ, Webber CA, Derfalvi B, Hammon Y, Rachubinski RA, Di Cara F. Modulation of the cell membrane lipid milieu by peroxisomal β-oxidation induces Rho1 signaling to trigger inflammatory responses. Cell Rep 2022; 38:110433. [PMID: 35235794 DOI: 10.1016/j.celrep.2022.110433] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 12/21/2021] [Accepted: 02/01/2022] [Indexed: 12/11/2022] Open
Abstract
Phagocytosis, signal transduction, and inflammatory responses require changes in lipid metabolism. Peroxisomes have key roles in fatty acid homeostasis and in regulating immune function. We find that Drosophila macrophages lacking peroxisomes have perturbed lipid profiles, which reduce host survival after infection. Using lipidomic, transcriptomic, and genetic screens, we determine that peroxisomes contribute to the cell membrane glycerophospholipid composition necessary to induce Rho1-dependent signals, which drive cytoskeletal remodeling during macrophage activation. Loss of peroxisome function increases membrane phosphatidic acid (PA) and recruits RhoGAPp190 during infection, inhibiting Rho1-mediated responses. Peroxisome-glycerophospholipid-Rho1 signaling also controls cytoskeleton remodeling in mouse immune cells. While high levels of PA in cells without peroxisomes inhibit inflammatory phenotypes, large numbers of peroxisomes and low amounts of cell membrane PA are features of immune cells from patients with inflammatory Kawasaki disease and juvenile idiopathic arthritis. Our findings reveal potential metabolic markers and therapeutic targets for immune diseases and metabolic disorders.
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Affiliation(s)
- Anu S Nath
- Dalhousie University, Department of Microbiology and Immunology, Halifax, NS B3K 6R8, Canada
| | - Brendon D Parsons
- Dalhousie University, Department of Microbiology and Immunology, Halifax, NS B3K 6R8, Canada
| | - Stephanie Makdissi
- Dalhousie University, Department of Microbiology and Immunology, Halifax, NS B3K 6R8, Canada
| | - Rebecca L Chilvers
- Dalhousie University, Department of Microbiology and Immunology, Halifax, NS B3K 6R8, Canada
| | - Yizhu Mu
- Dalhousie University, Department of Microbiology and Immunology, Halifax, NS B3K 6R8, Canada
| | - Ceileigh M Weaver
- Dalhousie University, Department of Microbiology and Immunology, Halifax, NS B3K 6R8, Canada
| | - Irene Euodia
- Dalhousie University, Department of Microbiology and Immunology, Halifax, NS B3K 6R8, Canada
| | - Katherine A Fitze
- Dalhousie University, Department of Microbiology and Immunology, Halifax, NS B3K 6R8, Canada
| | - Juyang Long
- Dalhousie University, Department of Microbiology and Immunology, Halifax, NS B3K 6R8, Canada
| | - Michal Scur
- Dalhousie University, Department of Microbiology and Immunology, Halifax, NS B3K 6R8, Canada
| | - Duncan P Mackenzie
- Dalhousie University, Department of Microbiology and Immunology, Halifax, NS B3K 6R8, Canada
| | - Andrew P Makrigiannis
- Dalhousie University, Department of Microbiology and Immunology, Halifax, NS B3K 6R8, Canada
| | - Nicolas Pichaud
- Université de Moncton, Department of Chemistry and Biochemistry, Moncton, NB E1A 3E9, Canada; New Brunswick Centre for Precision Medicine (NBCPM), Moncton, NB E1A 3E9, Canada
| | - Luc H Boudreau
- Université de Moncton, Department of Chemistry and Biochemistry, Moncton, NB E1A 3E9, Canada; New Brunswick Centre for Precision Medicine (NBCPM), Moncton, NB E1A 3E9, Canada
| | - Andrew J Simmonds
- University of Alberta, Department of Cell Biology, Edmonton, AB T6G 2H7, Canada
| | - Christine A Webber
- University of Alberta, Department of Cell Biology, Edmonton, AB T6G 2H7, Canada
| | - Beata Derfalvi
- Dalhousie University, Department of Pediatrics, Halifax, NS B3K 6R8, Canada
| | - Yannick Hammon
- INSERM au Centre d'Immunologie de Marseille Luminy, Marseille 13288, France
| | | | - Francesca Di Cara
- Dalhousie University, Department of Microbiology and Immunology, Halifax, NS B3K 6R8, Canada; Dalhousie University, Department of Pediatrics, Halifax, NS B3K 6R8, Canada.
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9
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Doumane M, Caillaud MC, Jaillais Y. Experimental manipulation of phosphoinositide lipids: from cells to organisms. Trends Cell Biol 2022; 32:445-461. [DOI: 10.1016/j.tcb.2022.01.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Revised: 01/17/2022] [Accepted: 01/18/2022] [Indexed: 12/14/2022]
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10
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Fountain A, Inpanathan S, Alves P, Verdawala MB, Botelho RJ. Phagosome maturation in macrophages: Eat, digest, adapt, and repeat. Adv Biol Regul 2021; 82:100832. [PMID: 34717137 DOI: 10.1016/j.jbior.2021.100832] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 10/06/2021] [Indexed: 11/30/2022]
Abstract
Phagocytosis is a dynamic process that requires an intricate interplay between phagocytic receptors, membrane lipids, and numerous signalling proteins and their effectors, to coordinate the engulfment of a bound particle. These particles are diverse in their physico-chemical properties such as size and shape and include bacteria, fungi, apoptotic cells, living tumour cells, and abiotic particles. Once engulfed, these particles are enclosed within a phagosome, which undergoes a striking transformation referred to as phagosome maturation, which will ultimately lead to the processing and degradation of the enclosed particulate. In this review, we focus on recent advancements in phagosome maturation in macrophages, highlighting new discoveries and emerging themes. Such advancements include identification of new GTPases and their effectors and the intricate spatio-temporal dynamics of phosphoinositides in governing phagosome maturation. We then explore phagosome fission and recycling, the emerging role of membrane contact sites, and delve into mechanisms of phagosome resolution to recycle and reform lysosomes. We further illustrate how phagosome maturation is context-dependent, subject to the type of particle, phagocytic receptors, the phagocytes and their state of activation during phagocytosis. Lastly, we discuss how phagosomes serve as signalling platforms to help phagocytes adapt to their environmental conditions. Overall, this review aims to cover recent findings, identify emerging themes, and highlight current challenges and directions to improve our understanding of phagosome maturation in macrophages.
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Affiliation(s)
- Aaron Fountain
- Department of Chemistry and Biology and Graduate Program in Molecular Science, Ryerson University, Toronto, Ontario, M5B2K3, Canada; Graduate Program in Molecular Science, Ryerson University, Toronto, Ontario, M5B2K3, Canada
| | - Subothan Inpanathan
- Department of Chemistry and Biology and Graduate Program in Molecular Science, Ryerson University, Toronto, Ontario, M5B2K3, Canada; Graduate Program in Molecular Science, Ryerson University, Toronto, Ontario, M5B2K3, Canada
| | - Patris Alves
- Department of Chemistry and Biology and Graduate Program in Molecular Science, Ryerson University, Toronto, Ontario, M5B2K3, Canada; Graduate Program in Molecular Science, Ryerson University, Toronto, Ontario, M5B2K3, Canada
| | - Munira B Verdawala
- Department of Chemistry and Biology and Graduate Program in Molecular Science, Ryerson University, Toronto, Ontario, M5B2K3, Canada
| | - Roberto J Botelho
- Department of Chemistry and Biology and Graduate Program in Molecular Science, Ryerson University, Toronto, Ontario, M5B2K3, Canada; Graduate Program in Molecular Science, Ryerson University, Toronto, Ontario, M5B2K3, Canada.
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11
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Nakatsu F, Kawasaki A. Functions of Oxysterol-Binding Proteins at Membrane Contact Sites and Their Control by Phosphoinositide Metabolism. Front Cell Dev Biol 2021; 9:664788. [PMID: 34249917 PMCID: PMC8264513 DOI: 10.3389/fcell.2021.664788] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2021] [Accepted: 05/06/2021] [Indexed: 01/10/2023] Open
Abstract
Lipids must be correctly transported within the cell to the right place at the right time in order to be fully functional. Non-vesicular lipid transport is mediated by so-called lipid transfer proteins (LTPs), which contain a hydrophobic cavity that sequesters lipid molecules. Oxysterol-binding protein (OSBP)-related proteins (ORPs) are a family of LTPs known to harbor lipid ligands, such as cholesterol and phospholipids. ORPs act as a sensor or transporter of those lipid ligands at membrane contact sites (MCSs) where two different cellular membranes are closely apposed. In particular, a characteristic functional property of ORPs is their role as a lipid exchanger. ORPs mediate counter-directional transport of two different lipid ligands at MCSs. Several, but not all, ORPs transport their lipid ligand from the endoplasmic reticulum (ER) in exchange for phosphatidylinositol 4-phosphate (PI4P), the other ligand, on apposed membranes. This ORP-mediated lipid “countertransport” is driven by the concentration gradient of PI4P between membranes, which is generated by its kinases and phosphatases. In this review, we will discuss how ORP function is tightly coupled to metabolism of phosphoinositides such as PI4P. Recent progress on the role of ORP-mediated lipid transport/countertransport at multiple MCSs in cellular functions will be also discussed.
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Affiliation(s)
- Fubito Nakatsu
- Department of Neurochemistry and Molecular Cell Biology, Niigata University School of Medicine and Graduate School of Medical/Dental Sciences, Niigata, Japan
| | - Asami Kawasaki
- Department of Neurochemistry and Molecular Cell Biology, Niigata University School of Medicine and Graduate School of Medical/Dental Sciences, Niigata, Japan
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12
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Batrouni AG, Baskin JM. The chemistry and biology of phosphatidylinositol 4-phosphate at the plasma membrane. Bioorg Med Chem 2021; 40:116190. [PMID: 33965837 DOI: 10.1016/j.bmc.2021.116190] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 04/24/2021] [Accepted: 04/26/2021] [Indexed: 12/29/2022]
Abstract
Phosphoinositides are an important class of anionic, low abundance signaling lipids distributed throughout intracellular membranes. The plasma membrane contains three phosphoinositides: PI(4)P, PI(4,5)P2, and PI(3,4,5)P3. Of these, PI(4)P has remained the most mysterious, despite its characterization in this membrane more than a half-century ago. Fortunately, recent methodological innovations at the chemistry-biology interface have spurred a renaissance of interest in PI(4)P. Here, we describe these new toolsets and how they have revealed novel functions for the plasma membrane PI(4)P pool. We examine high-resolution structural characterization of the plasma membrane PI 4-kinase complex that produces PI(4)P, tools for modulating PI(4)P levels including isoform-selective PI 4-kinase inhibitors, and fluorescent probes for visualizing PI(4)P. Collectively, these chemical and biochemical approaches have revealed insights into how cells regulate synthesis of PI(4)P and its downstream metabolites as well as new roles for plasma membrane PI(4)P in non-vesicular lipid transport, membrane homeostasis and trafficking, and cell signaling pathways.
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Affiliation(s)
- Alex G Batrouni
- Department of Chemistry and Chemical Biology and Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853, USA
| | - Jeremy M Baskin
- Department of Chemistry and Chemical Biology and Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853, USA.
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13
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Dixon CL, Mekhail K, Fairn GD. Examining the Underappreciated Role of S-Acylated Proteins as Critical Regulators of Phagocytosis and Phagosome Maturation in Macrophages. Front Immunol 2021; 12:659533. [PMID: 33868308 PMCID: PMC8047069 DOI: 10.3389/fimmu.2021.659533] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Accepted: 03/15/2021] [Indexed: 12/04/2022] Open
Abstract
Phagocytosis is a receptor-mediated process used by cells to engulf a wide variety of particulates, including microorganisms and apoptotic cells. Many of the proteins involved in this highly orchestrated process are post-translationally modified with lipids as a means of regulating signal transduction, membrane remodeling, phagosome maturation and other immunomodulatory functions of phagocytes. S-acylation, generally referred to as S-palmitoylation, is the post-translational attachment of fatty acids to a cysteine residue exposed topologically to the cytosol. This modification is reversible due to the intrinsically labile thioester bond between the lipid and sulfur atom of cysteine, and thus lends itself to a variety of regulatory scenarios. Here we present an overview of a growing number of S-acylated proteins known to regulate phagocytosis and phagosome biology in macrophages.
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Affiliation(s)
- Charneal L Dixon
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Unity Health Toronto, Toronto, ON, Canada.,Department of Biochemistry, University of Toronto, Toronto, ON, Canada
| | - Katrina Mekhail
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Unity Health Toronto, Toronto, ON, Canada.,Department of Biochemistry, University of Toronto, Toronto, ON, Canada
| | - Gregory D Fairn
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Unity Health Toronto, Toronto, ON, Canada.,Department of Biochemistry, University of Toronto, Toronto, ON, Canada.,Department of Surgery, University of Toronto, Toronto, ON, Canada.,Department of Laboratory Medicine and Pathobiology, Toronto, ON, Canada
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14
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Ernest James Phillips T, Maguire E. Phosphoinositides: Roles in the Development of Microglial-Mediated Neuroinflammation and Neurodegeneration. Front Cell Neurosci 2021; 15:652593. [PMID: 33841102 PMCID: PMC8032904 DOI: 10.3389/fncel.2021.652593] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Accepted: 03/08/2021] [Indexed: 12/11/2022] Open
Abstract
Microglia are increasingly recognized as vital players in the pathology of a variety of neurodegenerative conditions including Alzheimer’s (AD) and Parkinson’s (PD) disease. While microglia have a protective role in the brain, their dysfunction can lead to neuroinflammation and contributes to disease progression. Also, a growing body of literature highlights the seven phosphoinositides, or PIPs, as key players in the regulation of microglial-mediated neuroinflammation. These small signaling lipids are phosphorylated derivates of phosphatidylinositol, are enriched in the brain, and have well-established roles in both homeostasis and disease.Disrupted PIP levels and signaling has been detected in a variety of dementias. Moreover, many known AD disease modifiers identified via genetic studies are expressed in microglia and are involved in phospholipid metabolism. One of these, the enzyme PLCγ2 that hydrolyzes the PIP species PI(4,5)P2, displays altered expression in AD and PD and is currently being investigated as a potential therapeutic target.Perhaps unsurprisingly, neurodegenerative conditions exhibiting PIP dyshomeostasis also tend to show alterations in aspects of microglial function regulated by these lipids. In particular, phosphoinositides regulate the activities of proteins and enzymes required for endocytosis, toll-like receptor signaling, purinergic signaling, chemotaxis, and migration, all of which are affected in a variety of neurodegenerative conditions. These functions are crucial to allow microglia to adequately survey the brain and respond appropriately to invading pathogens and other abnormalities, including misfolded proteins. AD and PD therapies are being developed to target many of the above pathways, and although not yet investigated, simultaneous PIP manipulation might enhance the beneficial effects observed. Currently, only limited therapeutics are available for dementia, and although these show some benefits for symptom severity and progression, they are far from curative. Given the importance of microglia and PIPs in dementia development, this review summarizes current research and asks whether we can exploit this information to design more targeted, or perhaps combined, dementia therapeutics. More work is needed to fully characterize the pathways discussed in this review, but given the strength of the current literature, insights in this area could be invaluable for the future of neurodegenerative disease research.
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Affiliation(s)
| | - Emily Maguire
- UK Dementia Research Institute at Cardiff University, Cardiff, United Kingdom
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15
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Nguyen JA, Yates RM. Better Together: Current Insights Into Phagosome-Lysosome Fusion. Front Immunol 2021; 12:636078. [PMID: 33717183 PMCID: PMC7946854 DOI: 10.3389/fimmu.2021.636078] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 01/18/2021] [Indexed: 12/15/2022] Open
Abstract
Following phagocytosis, the nascent phagosome undergoes maturation to become a phagolysosome with an acidic, hydrolytic, and often oxidative lumen that can efficiently kill and digest engulfed microbes, cells, and debris. The fusion of phagosomes with lysosomes is a principal driver of phagosomal maturation and is targeted by several adapted intracellular pathogens. Impairment of this process has significant consequences for microbial infection, tissue inflammation, the onset of adaptive immunity, and disease. Given the importance of phagosome-lysosome fusion to phagocyte function and the many virulence factors that target it, it is unsurprising that multiple molecular pathways have evolved to mediate this essential process. While the full range of these pathways has yet to be fully characterized, several pathways involving proteins such as members of the Rab GTPases, tethering factors and SNAREs have been identified. Here, we summarize the current state of knowledge to clarify the ambiguities in the field and construct a more comprehensive phagolysosome formation model. Lastly, we discuss how other cellular pathways help support phagolysosome biogenesis and, consequently, phagocyte function.
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Affiliation(s)
- Jenny A Nguyen
- Department of Biochemistry and Molecular Biology, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Robin M Yates
- Department of Biochemistry and Molecular Biology, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.,Department of Comparative Biology and Experimental Medicine, Faculty of Veterinary Medicine, University of Calgary, Calgary, AB, Canada.,Cumming School of Medicine, Snyder Institute of Chronic Disease, University of Calgary, Calgary, AB, Canada
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16
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Phosphatidylinositol 3-Phosphate Mediates the Establishment of Infectious Bursal Disease Virus Replication Complexes in Association with Early Endosomes. J Virol 2021; 95:JVI.02313-20. [PMID: 33361427 DOI: 10.1128/jvi.02313-20] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Accepted: 12/15/2020] [Indexed: 12/13/2022] Open
Abstract
Infectious bursal disease virus (IBDV) is the archetypal member of the family Birnaviridae and the etiological agent of Gumboro disease, a highly contagious immunosuppressive infection of concern to the global poultry sector for its adverse health effects in chicks. Unlike most double-stranded RNA (dsRNA) viruses, which enclose their genomes within specialized cores throughout their viral replication cycle, birnaviruses organize their bisegmented dsRNA genome in ribonucleoprotein (RNP) structures. Recently, we demonstrated that IBDV exploits endosomal membranes for replication. The establishment of IBDV replication machinery on the cytosolic leaflet of endosomal compartments is mediated by the viral protein VP3 and its intrinsic ability to target endosomes. In this study, we identified the early endosomal phosphatidylinositol 3-phosphate [PtdIns(3)P] as a key host factor of VP3 association with endosomal membranes and consequent establishment of IBDV replication complexes in early endosomes. Indeed, our data reveal a crucial role for PtdIns(3)P in IBDV replication. Overall, our findings provide new insights into the replicative strategy of birnaviruses and strongly suggest that it resembles those of positive-strand RNA (+ssRNA) viruses, which replicate in association with host membranes. Furthermore, our findings support the role of birnaviruses as evolutionary intermediaries between +ssRNA and dsRNA viruses and, importantly, demonstrate a novel role for PtdIns(3)P in the replication of a dsRNA virus.IMPORTANCE Infectious bursal disease virus (IBDV) infects chicks and is the causative agent of Gumboro disease. During IBDV outbreaks in recent decades, the emergence of very virulent variants and the lack of effective prevention/treatment strategies to fight this disease have had devastating consequences for the poultry industry. IBDV belongs to the peculiar family Birnaviridae Unlike most dsRNA viruses, birnaviruses organize their genomes in ribonucleoprotein complexes and replicate in a core-independent manner. We recently demonstrated that IBDV exploits host cell endosomes as platforms for viral replication, a process that depends on the VP3 viral protein. In this study, we delved deeper into the molecular characterization of IBDV-endosome association and investigated the role of host cell phosphatidylinositide lipids in VP3 protein localization and IBDV infection. Together, our findings demonstrate that PtdIns(3)P serves as a scaffold for the association of VP3 to endosomes and reveal its essential role for IBDV replication.
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17
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Montaño-Rendón F, Grinstein S, Walpole GFW. Monitoring Phosphoinositide Fluxes and Effectors During Leukocyte Chemotaxis and Phagocytosis. Front Cell Dev Biol 2021; 9:626136. [PMID: 33614656 PMCID: PMC7890364 DOI: 10.3389/fcell.2021.626136] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Accepted: 01/06/2021] [Indexed: 01/22/2023] Open
Abstract
The dynamic re-organization of cellular membranes in response to extracellular stimuli is fundamental to the cell physiology of myeloid and lymphoid cells of the immune system. In addition to maintaining cellular homeostatic functions, remodeling of the plasmalemma and endomembranes endow leukocytes with the potential to relay extracellular signals across their biological membranes to promote rolling adhesion and diapedesis, migration into the tissue parenchyma, and to ingest foreign particles and effete cells. Phosphoinositides, signaling lipids that control the interface of biological membranes with the external environment, are pivotal to this wealth of functions. Here, we highlight the complex metabolic transitions that occur to phosphoinositides during several stages of the leukocyte lifecycle, namely diapedesis, migration, and phagocytosis. We describe classical and recently developed tools that have aided our understanding of these complex lipids. Finally, major downstream effectors of inositides are highlighted including the cytoskeleton, emphasizing the importance of these rare lipids in immunity and disease.
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Affiliation(s)
- Fernando Montaño-Rendón
- Program in Cell Biology, Hospital for Sick Children, Toronto, ON, Canada.,Institute of Medical Sciences, University of Toronto, Toronto, ON, Canada
| | - Sergio Grinstein
- Program in Cell Biology, Hospital for Sick Children, Toronto, ON, Canada.,Institute of Medical Sciences, University of Toronto, Toronto, ON, Canada.,Department of Biochemistry, University of Toronto, Toronto, ON, Canada.,Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto, ON, Canada
| | - Glenn F W Walpole
- Program in Cell Biology, Hospital for Sick Children, Toronto, ON, Canada.,Department of Biochemistry, University of Toronto, Toronto, ON, Canada
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18
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Abstract
Lipids, like phosphoinositides, can be visualized in living cells in real time using genetically encoded biosensors and fluorescence microscopy. Sensor localization can be quantified by determining the fluorescence intensity of each fluorophore. Enrichment of lipids at membranes can be determined by generating and applying an organelle-specific binary mask. In this chapter, we provide a detailed list of reagents and methods to visualize and quantify relative lipid levels. Applying this approach, changes in lipid levels can be assessed in cases when lipid metabolizing enzymes are mutated or otherwise altered.
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Affiliation(s)
- Rachel C Wills
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Jonathan Pacheco
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Gerald R V Hammond
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
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19
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López-Haber C, Levin-Konigsberg R, Zhu Y, Bi-Karchin J, Balla T, Grinstein S, Marks MS, Mantegazza AR. Phosphatidylinositol-4-kinase IIα licenses phagosomes for TLR4 signaling and MHC-II presentation in dendritic cells. Proc Natl Acad Sci U S A 2020; 117:28251-28262. [PMID: 33109721 PMCID: PMC7668187 DOI: 10.1073/pnas.2001948117] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Toll-like receptor (TLR) recruitment to phagosomes in dendritic cells (DCs) and downstream TLR signaling are essential to initiate antimicrobial immune responses. However, the mechanisms underlying TLR localization to phagosomes are poorly characterized. We show herein that phosphatidylinositol-4-kinase IIα (PI4KIIα) plays a key role in initiating phagosomal TLR4 responses in murine DCs by generating a phosphatidylinositol-4-phosphate (PtdIns4P) platform conducive to the binding of the TLR sorting adaptor Toll-IL1 receptor (TIR) domain-containing adaptor protein (TIRAP). PI4KIIα is recruited to maturing lipopolysaccharide (LPS)-containing phagosomes in an adaptor protein-3 (AP-3)-dependent manner, and both PI4KIIα and PtdIns4P are detected on phagosomal membrane tubules. Knockdown of PI4KIIα-but not the related PI4KIIβ-impairs TIRAP and TLR4 localization to phagosomes, reduces proinflammatory cytokine secretion, abolishes phagosomal tubule formation, and impairs major histocompatibility complex II (MHC-II) presentation. Phagosomal TLR responses in PI4KIIα-deficient DCs are restored by reexpression of wild-type PI4KIIα, but not of variants lacking kinase activity or AP-3 binding. Our data indicate that PI4KIIα is an essential regulator of phagosomal TLR signaling in DCs by ensuring optimal TIRAP recruitment to phagosomes.
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Affiliation(s)
- Cynthia López-Haber
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Philadelphia, PA 19104
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Roni Levin-Konigsberg
- Division of Cell Biology, Hospital for Sick Children, Toronto, ON M5G 1X8, Canada
- Department of Biochemistry, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Yueyao Zhu
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Philadelphia, PA 19104
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Jing Bi-Karchin
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Philadelphia, PA 19104
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Tamas Balla
- Section on Molecular Signal Transduction, Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, MD 20892
| | - Sergio Grinstein
- Division of Cell Biology, Hospital for Sick Children, Toronto, ON M5G 1X8, Canada
- Department of Biochemistry, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Michael S Marks
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Philadelphia, PA 19104
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Adriana R Mantegazza
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Philadelphia, PA 19104;
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
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20
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Levin-Konigsberg R, Mantegazza AR. A guide to measuring phagosomal dynamics. FEBS J 2020; 288:1412-1433. [PMID: 32757358 PMCID: PMC7984381 DOI: 10.1111/febs.15506] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 07/07/2020] [Accepted: 07/31/2020] [Indexed: 02/06/2023]
Abstract
Phagocytosis is an essential mechanism for immunity and homeostasis, performed by a subset of cells known as phagocytes. Upon target engulfment, de novo formation of specialized compartments termed phagosomes takes place. Phagosomes then undergo a series of fusion and fission events as they interact with the endolysosomal system and other organelles, in a dynamic process known as phagosome maturation. Because phagocytes play a key role in tissue patrolling and immune surveillance, phagosome maturation is associated with signaling pathways that link phagocytosis to antigen presentation and the development of adaptive immune responses. In addition, and depending on the nature of the cargo, phagosome integrity may be compromised, triggering additional cellular mechanisms including inflammation and autophagy. Upon completion of maturation, phagosomes enter a recently described phase: phagosome resolution, where catabolites from degraded cargo are metabolized, phagosomes are resorbed, and vesicles of phagosomal origin are recycled. Finally, phagocytes return to homeostasis and become ready for a new round of phagocytosis. Altogether, phagosome maturation and resolution encompass a series of dynamic events and organelle crosstalk that can be measured by biochemical, imaging, photoluminescence, cytometric, and immune‐based assays that will be described in this guide.
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Affiliation(s)
| | - Adriana R Mantegazza
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Philadelphia, PA, USA.,Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
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21
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Sachdeva K, Goel M, Sudhakar M, Mehta M, Raju R, Raman K, Singh A, Sundaramurthy V. Mycobacterium tuberculosis ( Mtb) lipid mediated lysosomal rewiring in infected macrophages modulates intracellular Mtb trafficking and survival. J Biol Chem 2020; 295:9192-9210. [PMID: 32424041 PMCID: PMC7335774 DOI: 10.1074/jbc.ra120.012809] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Revised: 05/14/2020] [Indexed: 12/24/2022] Open
Abstract
Intracellular pathogens commonly manipulate the host lysosomal system for their survival. However, whether this pathogen-induced alteration affects the organization and functioning of the lysosomal system itself is not known. Here, using in vitro and in vivo infections and quantitative image analysis, we show that the lysosomal content and activity are globally elevated in Mycobacterium tuberculosis (Mtb)-infected macrophages. We observed that this enhanced lysosomal state is sustained over time and defines an adaptive homeostasis in the infected macrophage. Lysosomal alterations are caused by mycobacterial surface components, notably the cell wall-associated lipid sulfolipid-1 (SL-1), which functions through the mTOR complex 1 (mTORC1)-transcription factor EB (TFEB) axis in the host cells. An Mtb mutant lacking SL-1, MtbΔpks2, shows attenuated lysosomal rewiring compared with the WT Mtb in both in vitro and in vivo infections. Exposing macrophages to purified SL-1 enhanced the trafficking of phagocytic cargo to lysosomes. Correspondingly, MtbΔpks2 exhibited a further reduction in lysosomal delivery compared with the WT. Reduced trafficking of this mutant Mtb strain to lysosomes correlated with enhanced intracellular bacterial survival. Our results reveal that global alteration of the host lysosomal system is a defining feature of Mtb-infected macrophages and suggest that this altered lysosomal state protects host cell integrity and contributes to the containment of the pathogen.
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Affiliation(s)
- Kuldeep Sachdeva
- National Center for Biological Sciences, Tata Institute of Fundamental Research, Bengaluru, India
| | - Manisha Goel
- National Center for Biological Sciences, Tata Institute of Fundamental Research, Bengaluru, India
| | - Malvika Sudhakar
- Department of Biotechnology, Indian Institute of Technology Madras, Chennai, India; Initiative for Biological Systems Engineering, Robert Bosch Centre for Data Science and Artificial Intelligence (RBC-DSAI), Indian Institute of Technology Madras, Chennai, India
| | - Mansi Mehta
- Center for Infectious Disease Research, Department of Microbiology and Cell Biology, Indian Institute of Science, Bengaluru, India
| | - Rajmani Raju
- Center for Infectious Disease Research, Department of Microbiology and Cell Biology, Indian Institute of Science, Bengaluru, India
| | - Karthik Raman
- Department of Biotechnology, Indian Institute of Technology Madras, Chennai, India; Initiative for Biological Systems Engineering, Robert Bosch Centre for Data Science and Artificial Intelligence (RBC-DSAI), Indian Institute of Technology Madras, Chennai, India
| | - Amit Singh
- Center for Infectious Disease Research, Department of Microbiology and Cell Biology, Indian Institute of Science, Bengaluru, India
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22
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Affiliation(s)
- Francesca Di Cara
- Department of Microbiology and Immunology-IWK Health Centre- Dalhousie University, Halifax (NS), Canada
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23
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Banerjee S, Kane PM. Regulation of V-ATPase Activity and Organelle pH by Phosphatidylinositol Phosphate Lipids. Front Cell Dev Biol 2020; 8:510. [PMID: 32656214 PMCID: PMC7324685 DOI: 10.3389/fcell.2020.00510] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 05/28/2020] [Indexed: 12/14/2022] Open
Abstract
Luminal pH and the distinctive distribution of phosphatidylinositol phosphate (PIP) lipids are central identifying features of organelles in all eukaryotic cells that are also critical for organelle function. V-ATPases are conserved proton pumps that populate and acidify multiple organelles of the secretory and the endocytic pathway. Complete loss of V-ATPase activity causes embryonic lethality in higher animals and conditional lethality in yeast, while partial loss of V-ATPase function is associated with multiple disease states. On the other hand, many cancer cells increase their virulence by upregulating V-ATPase expression and activity. The pH of individual organelles is tightly controlled and essential for function, but the mechanisms for compartment-specific pH regulation are not completely understood. There is substantial evidence indicating that the PIP content of membranes influences organelle pH. We present recent evidence that PIPs interact directly with subunit isoforms of the V-ATPase to dictate localization of V-ATPase subpopulations and participate in their regulation. In yeast cells, which have only one set of organelle-specific V-ATPase subunit isoforms, the Golgi-enriched lipid PI(4)P binds to the cytosolic domain of the Golgi-enriched a-subunit isoform Stv1, and loss of PI(4)P binding results in mislocalization of Stv1-containing V-ATPases from the Golgi to the vacuole/lysosome. In contrast, levels of the vacuole/lysosome-enriched signaling lipid PI(3,5)P2 affect assembly and activity of V-ATPases containing the Vph1 a-subunit isoform. Mutations in the Vph1 isoform that disrupt the lipid interaction increase sensitivity to stress. These studies have decoded “zip codes” for PIP lipids in the cytosolic N-terminal domain of the a-subunit isoforms of the yeast V-ATPase, and similar interactions between PIP lipids and the V-ATPase subunit isoforms are emerging in higher eukaryotes. In addition to direct effects on the V-ATPase, PIP lipids are also likely to affect organelle pH indirectly, through interactions with other membrane transporters. We discuss direct and indirect effects of PIP lipids on organelle pH, and the functional consequences of the interplay between PIP lipid content and organelle pH.
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Affiliation(s)
- Subhrajit Banerjee
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, United States
| | - Patricia M Kane
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, United States
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24
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Walpole GFW, Grinstein S. Endocytosis and the internalization of pathogenic organisms: focus on phosphoinositides. F1000Res 2020; 9. [PMID: 32494357 PMCID: PMC7233180 DOI: 10.12688/f1000research.22393.1] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/07/2020] [Indexed: 12/18/2022] Open
Abstract
Despite their comparatively low abundance in biological membranes, phosphoinositides are key to the regulation of a diverse array of signaling pathways and direct membrane traffic. The role of phosphoinositides in the initiation and progression of endocytic pathways has been studied in considerable depth. Recent advances have revealed that distinct phosphoinositide species feature prominently in clathrin-dependent and -independent endocytosis as well as in phagocytosis and macropinocytosis. Moreover, a variety of intracellular and cell-associated pathogens have developed strategies to commandeer host cell phosphoinositide metabolism to gain entry and/or metabolic advantage, thereby promoting their survival and proliferation. Here, we briefly survey the current knowledge on the involvement of phosphoinositides in endocytosis, phagocytosis, and macropinocytosis and highlight several examples of molecular mimicry employed by pathogens to either “hitch a ride” on endocytic pathways endogenous to the host or create an entry path of their own.
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Affiliation(s)
- Glenn F W Walpole
- Program in Cell Biology, Hospital for Sick Children, Toronto, ON, Canada.,Department of Biochemistry, University of Toronto, Toronto, ON, Canada
| | - Sergio Grinstein
- Program in Cell Biology, Hospital for Sick Children, Toronto, ON, Canada.,Department of Biochemistry, University of Toronto, Toronto, ON, Canada.,Keenan Research Centre of the Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, ON, Canada
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25
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Griffiths NW, Del Bel LM, Wilk R, Brill JA. Cellular homeostasis in the Drosophila retina requires the lipid phosphatase Sac1. Mol Biol Cell 2020; 31:1183-1199. [PMID: 32186963 PMCID: PMC7353163 DOI: 10.1091/mbc.e20-02-0161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The complex functions of cellular membranes, and thus overall cell physiology, depend on the distribution of crucial lipid species. Sac1 is an essential, conserved, ER-localized phosphatase whose substrate, phosphatidylinositol 4-phosphate (PI4P), coordinates secretory trafficking and plasma membrane function. PI4P from multiple pools is delivered to Sac1 by oxysterol-binding protein and related proteins in exchange for other lipids and sterols, which places Sac1 at the intersection of multiple lipid distribution pathways. However, much remains unknown about the roles of Sac1 in subcellular homeostasis and organismal development. Using a temperature-sensitive allele (Sac1ts), we show that Sac1 is required for structural integrity of the Drosophila retinal floor. The βps-integrin Myospheroid, which is necessary for basal cell adhesion, is mislocalized in Sac1ts retinas. In addition, the adhesion proteins Roughest and Kirre, which coordinate apical retinal cell patterning at an earlier stage, accumulate within Sac1ts retinal cells due to impaired endo-lysosomal degradation. Moreover, Sac1 is required for ER homeostasis in Drosophila retinal cells. Together, our data illustrate the importance of Sac1 in regulating multiple aspects of cellular homeostasis during tissue development.
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Affiliation(s)
- Nigel W Griffiths
- Cell Biology Program, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Lauren M Del Bel
- Cell Biology Program, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Ronit Wilk
- Cell Biology Program, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
| | - Julie A Brill
- Cell Biology Program, 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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26
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Giraud-Gatineau A, Coya JM, Maure A, Biton A, Thomson M, Bernard EM, Marrec J, Gutierrez MG, Larrouy-Maumus G, Brosch R, Gicquel B, Tailleux L. The antibiotic bedaquiline activates host macrophage innate immune resistance to bacterial infection. eLife 2020; 9:e55692. [PMID: 32369020 PMCID: PMC7200153 DOI: 10.7554/elife.55692] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Accepted: 04/04/2020] [Indexed: 12/12/2022] Open
Abstract
Antibiotics are widely used in the treatment of bacterial infections. Although known for their microbicidal activity, antibiotics may also interfere with the host's immune system. Here, we analyzed the effects of bedaquiline (BDQ), an inhibitor of the mycobacterial ATP synthase, on human macrophages. Genome-wide gene expression analysis revealed that BDQ reprogramed cells into potent bactericidal phagocytes. We found that 579 and 1,495 genes were respectively differentially expressed in naive- and M. tuberculosis-infected macrophages incubated with the drug, with an over-representation of lysosome-associated genes. BDQ treatment triggered a variety of antimicrobial defense mechanisms, including phagosome-lysosome fusion, and autophagy. These effects were associated with activation of transcription factor EB, involved in the transcription of lysosomal genes, resulting in enhanced intracellular killing of different bacterial species that were naturally insensitive to BDQ. Thus, BDQ could be used as a host-directed therapy against a wide range of bacterial infections.
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Affiliation(s)
- Alexandre Giraud-Gatineau
- Unit for Integrated Mycobacterial Pathogenomics, CNRS UMR 3525, Institut PasteurParisFrance
- Université Paris Diderot, Sorbonne Paris Cité, Cellule PasteurParisFrance
| | | | - Alexandra Maure
- Unit for Integrated Mycobacterial Pathogenomics, CNRS UMR 3525, Institut PasteurParisFrance
- Université Paris Diderot, Sorbonne Paris Cité, Cellule PasteurParisFrance
| | - Anne Biton
- Bioinformatics and Biostatistics, Department of Computational Biology, USR 3756 CNRS, Institut PasteurParisFrance
| | - Michael Thomson
- MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Faculty of Natural Sciences, Imperial College LondonLondonUnited Kingdom
| | - Elliott M Bernard
- Host-Pathogen Interactions in Tuberculosis Laboratory, The Francis Crick InstituteLondonUnited Kingdom
| | - Jade Marrec
- Mycobacterial Genetics Unit, Institut PasteurParisFrance
| | - Maximiliano G Gutierrez
- Host-Pathogen Interactions in Tuberculosis Laboratory, The Francis Crick InstituteLondonUnited Kingdom
| | - Gérald Larrouy-Maumus
- MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Faculty of Natural Sciences, Imperial College LondonLondonUnited Kingdom
| | - Roland Brosch
- Unit for Integrated Mycobacterial Pathogenomics, CNRS UMR 3525, Institut PasteurParisFrance
| | - Brigitte Gicquel
- Mycobacterial Genetics Unit, Institut PasteurParisFrance
- Department of Tuberculosis Control and Prevention, Shenzhen Nanshan Center for Chronic Disease ControlShenzhenChina
| | - Ludovic Tailleux
- Unit for Integrated Mycobacterial Pathogenomics, CNRS UMR 3525, Institut PasteurParisFrance
- Mycobacterial Genetics Unit, Institut PasteurParisFrance
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27
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The Role of Membrane Surface Charge in Phagocytosis. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1246:43-54. [DOI: 10.1007/978-3-030-40406-2_3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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28
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The NADPH Oxidase and the Phagosome. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1246:153-177. [DOI: 10.1007/978-3-030-40406-2_9] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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29
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Levin‐Konigsberg R, Grinstein S. Phagosome‐endoplasmic reticulum contacts: Kissing and not running. Traffic 2019; 21:172-180. [DOI: 10.1111/tra.12708] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Revised: 10/14/2019] [Accepted: 10/16/2019] [Indexed: 12/20/2022]
Affiliation(s)
| | - Sergio Grinstein
- Division of Cell BiologyHospital for Sick Children Toronto Ontario Canada
- Department of BiochemistryUniversity of Toronto Toronto Ontario Canada
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30
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Levin-Konigsberg R, Montaño-Rendón F, Keren-Kaplan T, Li R, Ego B, Mylvaganam S, DiCiccio JE, Trimble WS, Bassik MC, Bonifacino JS, Fairn GD, Grinstein S. Phagolysosome resolution requires contacts with the endoplasmic reticulum and phosphatidylinositol-4-phosphate signalling. Nat Cell Biol 2019; 21:1234-1247. [PMID: 31570833 DOI: 10.1038/s41556-019-0394-2] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Accepted: 08/19/2019] [Indexed: 01/01/2023]
Abstract
Phosphoinositides have a pivotal role in the maturation of nascent phagosomes into microbicidal phagolysosomes. Following degradation of their contents, mature phagolysosomes undergo resolution, a process that remains largely uninvestigated. Here we studied the role of phosphoinositides in phagolysosome resolution. Phosphatidylinositol-4-phosphate (PtdIns(4)P), which is abundant in maturing phagolysosomes, was depleted as they tubulated and resorbed. Depletion was caused, in part, by transfer of phagolysosomal PtdIns(4)P to the endoplasmic reticulum, a process mediated by oxysterol-binding protein-related protein 1L (ORP1L), a RAB7 effector. ORP1L formed discrete tethers between the phagolysosome and the endoplasmic reticulum, resulting in distinct regions with alternating PtdIns(4)P depletion and enrichment. Tubules emerged from PtdIns(4)P-rich regions, where ADP-ribosylation factor-like protein 8B (ARL8B) and SifA- and kinesin-interacting protein/pleckstrin homology domain-containing family M member 2 (SKIP/PLEKHM2) accumulated. SKIP binds preferentially to monophosphorylated phosphoinositides, of which PtdIns(4)P is most abundant in phagolysosomes, contributing to their tubulation. Accordingly, premature hydrolysis of PtdIns(4)P impaired SKIP recruitment and phagosome resolution. Thus, resolution involves phosphoinositides and tethering of phagolysosomes to the endoplasmic reticulum.
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Affiliation(s)
- Roni Levin-Konigsberg
- Division of Cell Biology, Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada.,Department of Genetics, Stanford University School of Medicine, Stanford, CA, USA
| | - Fernando Montaño-Rendón
- Division of Cell Biology, Hospital for Sick Children, Toronto, Ontario, Canada.,Institute of Medical Sciences, University of Toronto, Toronto, Ontario, Canada
| | - Tal Keren-Kaplan
- Cell Biology and Neurobiology Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Ren Li
- Division of Cell Biology, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Braeden Ego
- Department of Genetics, Stanford University School of Medicine, Stanford, CA, USA
| | - Sivakami Mylvaganam
- Division of Cell Biology, Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Jessica E DiCiccio
- Division of Cell Biology, Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - William S Trimble
- Division of Cell Biology, Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Michael C Bassik
- Department of Genetics, Stanford University School of Medicine, Stanford, CA, USA
| | - Juan S Bonifacino
- Cell Biology and Neurobiology Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Gregory D Fairn
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada. .,Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto, Ontario, Canada.
| | - Sergio Grinstein
- Division of Cell Biology, Hospital for Sick Children, Toronto, Ontario, Canada. .,Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada. .,Institute of Medical Sciences, University of Toronto, Toronto, Ontario, Canada. .,Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto, Ontario, Canada.
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31
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ER-lysosome contacts enable cholesterol sensing by mTORC1 and drive aberrant growth signalling in Niemann-Pick type C. Nat Cell Biol 2019; 21:1206-1218. [PMID: 31548609 PMCID: PMC6936960 DOI: 10.1038/s41556-019-0391-5] [Citation(s) in RCA: 173] [Impact Index Per Article: 34.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Accepted: 08/15/2019] [Indexed: 12/24/2022]
Abstract
Cholesterol activates the master growth regulator, mTORC1 kinase, by promoting its recruitment to the surface of lysosomes via the Rag guanosine triphosphatases (GTPases). The mechanisms that regulate lysosomal cholesterol content to enable mTORC1 signaling are unknown. We show that Oxysterol Binding Protein (OSBP) and its anchors at the endoplasmic reticulum (ER), VAPA/B, deliver cholesterol across ER-lysosome contacts to activate mTORC1. In cells lacking OSBP, but not other VAP-interacting cholesterol carriers, mTORC1 recruitment by the Rag GTPases is inhibited due to impaired cholesterol transport to lysosomes. Conversely, OSBP-mediated cholesterol trafficking drives constitutive mTORC1 activation in a disease model caused by loss of the lysosomal cholesterol transporter, Niemann-Pick C1 (NPC1). Chemical and genetic inactivation of OSBP suppresses aberrant mTORC1 signaling and restores autophagic function in cellular models of NPC. Thus, ER-lysosome contacts are signaling hubs that enable cholesterol sensing by mTORC1, and targeting their sterol-transfer activity could be beneficial in NPC.
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32
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Nguyen PM, Gandasi NR, Xie B, Sugahara S, Xu Y, Idevall-Hagren O. The PI(4)P phosphatase Sac2 controls insulin granule docking and release. J Cell Biol 2019; 218:3714-3729. [PMID: 31533953 PMCID: PMC6829663 DOI: 10.1083/jcb.201903121] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 06/20/2019] [Accepted: 08/08/2019] [Indexed: 12/12/2022] Open
Abstract
Insulin granule biogenesis involves transport to, and stable docking at, the plasma membrane before priming and fusion. Defects in this pathway result in impaired insulin secretion and are a hallmark of type 2 diabetes. We now show that the phosphatidylinositol 4-phosphate phosphatase Sac2 localizes to insulin granules in a substrate-dependent manner and that loss of Sac2 results in impaired insulin secretion. Sac2 operates upstream of granule docking, since loss of Sac2 prevented granule tethering to the plasma membrane and resulted in both reduced granule density and number of exocytic events. Sac2 levels correlated positively with the number of docked granules and exocytic events in clonal β cells and with insulin secretion in human pancreatic islets, and Sac2 expression was reduced in islets from type 2 diabetic subjects. Taken together, we identified a phosphoinositide switch on the surface on insulin granules that is required for stable granule docking at the plasma membrane and impaired in human type 2 diabetes.
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Affiliation(s)
- Phuoc My Nguyen
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
| | - Nikhil R Gandasi
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
| | - Beichen Xie
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
| | - Sari Sugahara
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden.,Laboratory of Health Chemistry, Graduate School of Pharmaceutical Sciences, University of Tokyo, Tokyo, Japan
| | - Yingke Xu
- Department of Biomedical Engineering, Key Laboratory of Biomedical Engineering of Ministry of Education, Zhejiang Provincial Key Laboratory of Cardio-Cerebral Vascular Detection Technology and Medicinal Effectiveness Appraisal, Zhejiang University, Hangzhou, China
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33
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Dynamic Podosome-Like Structures in Nascent Phagosomes Are Coordinated by Phosphoinositides. Dev Cell 2019; 50:397-410.e3. [DOI: 10.1016/j.devcel.2019.05.028] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Revised: 03/10/2019] [Accepted: 05/10/2019] [Indexed: 12/21/2022]
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34
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Fultz R, Engevik MA, Shi Z, Hall A, Herrmann B, Ganesh BP, Major A, Haag A, Mori-Akiyama Y, Versalovic J. Phagocytosis by macrophages depends on histamine H2 receptor signaling and scavenger receptor 1. Microbiologyopen 2019; 8:e908. [PMID: 31369218 PMCID: PMC6813435 DOI: 10.1002/mbo3.908] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Revised: 06/19/2019] [Accepted: 06/30/2019] [Indexed: 12/11/2022] Open
Abstract
The histamine H2 receptor (H2R) is a G protein‐coupled receptor that mediates cyclic AMP production, protein kinase A activation, and MAP kinase signaling. In order to explore the multifaceted effects of histamine signaling on immune cells, phagocytosis was evaluated using primary mouse‐derived macrophages. Phagocytosis is initiated by signaling via surface‐bound scavenger receptors and can be regulated by autophagy. Absence of H2R signaling resulted in diminished phagocytosis of live bacteria and synthetic microspheres by primary macrophages from histamine H2 receptor gene (Hrh2)‐deficient mice. Flow cytometry and immunofluorescence microscopy were used to quantify phagocytosis of phylogenetically diverse bacteria as well as microspheres of defined chemical composition. Autophagy and scavenger receptor gene expression were quantified in macrophages after exposure to Escherichia coli. Expression of the autophagy genes, Becn1 and Atg12, was increased in Hrh2−/− macrophages, indicating upregulation of autophagy pathways. Expression of the Macrophage Scavenger Receptor 1 gene (Msr1) was diminished in Hrh2‐deficient macrophages, supporting the possible importance of histamine signaling in scavenger receptor abundance and macrophage function. Flow cytometry confirmed diminished MSR1 surface abundance in Hrh2−/− macrophages. These data suggest that H2R signaling is required for effective phagocytosis by regulating the process of autophagy and scavenger receptor MSR1 abundance in macrophages.
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Affiliation(s)
- Robert Fultz
- Department of Pathology, Texas Children's Hospital, Houston, TX, USA.,Integrative Program in Molecular and Biomedical Sciences, Baylor College of Medicine, Houston, TX, USA
| | - Melinda A Engevik
- Department of Pathology, Texas Children's Hospital, Houston, TX, USA.,Department of Pathology & Immunology, Baylor College of Medicine, Houston, TX, USA
| | - Zhongcheng Shi
- Department of Pathology, Texas Children's Hospital, Houston, TX, USA.,Department of Pathology & Immunology, Baylor College of Medicine, Houston, TX, USA
| | - Anne Hall
- Department of Pathology, Texas Children's Hospital, Houston, TX, USA.,Molecular Virology & Microbiology, Baylor College of Medicine, Houston, TX, USA
| | - Beatrice Herrmann
- Cell and Molecular Biology Graduate Group, University of Pennsylvania, Philadelphia, PA, USA
| | - Bhanu P Ganesh
- Department of Neurology, University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Angela Major
- Department of Pathology, Texas Children's Hospital, Houston, TX, USA
| | - Anthony Haag
- Department of Pathology, Texas Children's Hospital, Houston, TX, USA.,Department of Pathology & Immunology, Baylor College of Medicine, Houston, TX, USA
| | - Yuko Mori-Akiyama
- Department of Pathology, Texas Children's Hospital, Houston, TX, USA.,Department of Pathology & Immunology, Baylor College of Medicine, Houston, TX, USA
| | - James Versalovic
- Department of Pathology, Texas Children's Hospital, Houston, TX, USA.,Department of Pathology & Immunology, Baylor College of Medicine, Houston, TX, USA
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D'Souza Z, Blackburn JB, Kudlyk T, Pokrovskaya ID, Lupashin VV. Defects in COG-Mediated Golgi Trafficking Alter Endo-Lysosomal System in Human Cells. Front Cell Dev Biol 2019; 7:118. [PMID: 31334232 PMCID: PMC6616090 DOI: 10.3389/fcell.2019.00118] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Accepted: 06/11/2019] [Indexed: 12/27/2022] Open
Abstract
The conserved oligomeric complex (COG) is a multi-subunit vesicle tethering complex that functions in retrograde trafficking at the Golgi. We have previously demonstrated that the formation of enlarged endo-lysosomal structures (EELSs) is one of the major glycosylation-independent phenotypes of cells depleted for individual COG complex subunits. Here, we characterize the EELSs in HEK293T cells using microscopy and biochemical approaches. Our analysis revealed that the EELSs are highly acidic and that vATPase-dependent acidification is essential for the maintenance of this enlarged compartment. The EELSs are accessible to both trans-Golgi enzymes and endocytic cargo. Moreover, the EELSs specifically accumulate endolysosomal proteins Lamp2, CD63, Rab7, Rab9, Rab39, Vamp7, and STX8 on their surface. The EELSs are distinct from lysosomes and do not accumulate active Cathepsin B. Retention using selective hooks (RUSH) experiments revealed that biosynthetic cargo mCherry-Lamp1 reaches the EELSs much faster as compared to both receptor-mediated and soluble endocytic cargo, indicating TGN origin of the EELSs. In support to this hypothesis, EELSs are enriched with TGN specific lipid PI4P. Additionally, analysis of COG4/VPS54 double KO cells revealed that the activity of the GARP tethering complex is necessary for EELSs’ accumulation, indicating that protein mistargeting and the imbalance of Golgi-endosome membrane flow leads to the formation of EELSs in COG-deficient cells. The EELSs are likely to serve as a degradative storage hybrid organelle for mistargeted Golgi enzymes and underglycosylated glycoconjugates. To our knowledge this is the first report of the formation of an enlarged hybrid endosomal compartment in a response to malfunction of the intra-Golgi trafficking machinery.
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Affiliation(s)
- Zinia D'Souza
- Department of Physiology, University of Arkansas for Medical Sciences, Little Rock, AR, United States
| | - Jessica Bailey Blackburn
- Department of Physiology, University of Arkansas for Medical Sciences, Little Rock, AR, United States
| | - Tetyana Kudlyk
- Department of Physiology, University of Arkansas for Medical Sciences, Little Rock, AR, United States
| | - Irina D Pokrovskaya
- Department of Physiology, University of Arkansas for Medical Sciences, Little Rock, AR, United States
| | - Vladimir V Lupashin
- Department of Physiology, University of Arkansas for Medical Sciences, Little Rock, AR, United States
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36
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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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37
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Saffi GT, Botelho RJ. Lysosome Fission: Planning for an Exit. Trends Cell Biol 2019; 29:635-646. [PMID: 31171420 DOI: 10.1016/j.tcb.2019.05.003] [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: 04/04/2019] [Revised: 05/01/2019] [Accepted: 05/03/2019] [Indexed: 01/26/2023]
Abstract
Lysosomes are acidic and degradative organelles that receive and digest a plethora of molecular and particulate cargo delivered by endocytosis, autophagy, and phagocytosis. The mechanisms responsible for sorting, transporting, and ultimately delivering membranes and cargo to lysosomes through fusion have been intensely investigated. Much less is understood about lysosome fission, which is necessary to balance the incessant flow of cargo into lysosomes and maintain steady-state number, size, and function of lysosomes. Here, we review the emerging picture of how lipid signals, coat and adaptor proteins, and motor-cytoskeletal assemblies drive budding, tubulation, splitting, and 'kiss-and-run' events that enable fission and exit from lysosomes and related organelles.
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Affiliation(s)
- Golam T Saffi
- Department of Chemistry and Biology and the Molecular Science Graduate Program, Ryerson University, Toronto, ONT, M5B2K3, Canada
| | - Roberto J Botelho
- Department of Chemistry and Biology and the Molecular Science Graduate Program, Ryerson University, Toronto, ONT, M5B2K3, Canada.
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38
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Pike CM, Boyer-Andersen R, Kinch LN, Caplan JL, Neunuebel MR. The Legionella effector RavD binds phosphatidylinositol-3-phosphate and helps suppress endolysosomal maturation of the Legionella-containing vacuole. J Biol Chem 2019; 294:6405-6415. [PMID: 30733336 PMCID: PMC6484141 DOI: 10.1074/jbc.ra118.007086] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 01/17/2019] [Indexed: 12/25/2022] Open
Abstract
Upon phagocytosis into macrophages, the intracellular bacterial pathogen Legionella pneumophila secretes effector proteins that manipulate host cell components, enabling it to evade lysosomal degradation. However, the bacterial proteins involved in this evasion are incompletely characterized. Here we show that the L. pneumophila effector protein RavD targets host membrane compartments and contributes to the molecular mechanism the pathogen uses to prevent encounters with lysosomes. Protein-lipid binding assays revealed that RavD selectively binds phosphatidylinositol-3-phosphate (PI(3)P) in vitro We further determined that a C-terminal RavD region mediates the interaction with PI(3)P and that this interaction requires Arg-292. In transiently transfected mammalian cells, mCherry-RavD colocalized with the early endosome marker EGFP-Rab5 as well as the PI(3)P biosensor EGFP-2×FYVE. However, treatment with the phosphoinositide 3-kinase inhibitor wortmannin did not disrupt localization of mCherry-RavD to endosomal compartments, suggesting that RavD's interaction with PI(3)P is not necessary to anchor RavD to endosomal membranes. Using superresolution and immunogold transmission EM, we observed that, upon translocation into macrophages, RavD was retained onto the Legionella-containing vacuole and was also present on small vesicles adjacent to the vacuole. We also report that despite no detectable effects on intracellular growth of L. pneumophila within macrophages or amebae, the lack of RavD significantly increased the number of vacuoles that accumulate the late endosome/lysosome marker LAMP-1 during macrophage infection. Together, our findings suggest that, although not required for intracellular replication of L. pneumophila, RavD is a part of the molecular mechanism that steers the Legionella-containing vacuole away from endolysosomal maturation pathways.
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Affiliation(s)
| | | | - Lisa N Kinch
- the Howard Hughes Medical Institute, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390
| | - Jeffrey L Caplan
- From the Delaware Biotechnology Institute and
- Departments of Biological Sciences and
- Plant and Soil Sciences, University of Delaware, Newark, Delaware 19716 and
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Abstract
Lipids convey both structural and functional properties to eukaryotic membranes. Understanding the basic lipid composition and the dynamics of these important molecules, in the context of cellular membranes, can shed light on signaling, metabolism, trafficking, and even membrane identity. The development of genetically encoded lipid biosensors has allowed for the visualization of specific lipids inside individual, living cells. However, a number of caveats and considerations have emerged with the overexpression of these biosensors. In this Technical Perspective, we provide a current list of available genetically encoded lipid biosensors, together with criteria that determine their veracity. We also provide some suggestions for the optimal utilization of these biosensors when both designing experiments and interpreting results.
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Affiliation(s)
- Rachel C Wills
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 16261
| | - Brady D Goulden
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 16261
| | - Gerald R V Hammond
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 16261
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40
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Ijuin T. Phosphoinositide phosphatases in cancer cell dynamics-Beyond PI3K and PTEN. Semin Cancer Biol 2019; 59:50-65. [PMID: 30922959 DOI: 10.1016/j.semcancer.2019.03.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Revised: 03/18/2019] [Accepted: 03/18/2019] [Indexed: 12/16/2022]
Abstract
Phosphoinositides are a group of lipids that regulate intracellular signaling and subcellular biological events. The signaling by phosphatidylinositol-3,4,5-trisphosphate and Akt mediates the action of growth factors that are essential for cell proliferation, gene transcription, cell migration, and polarity. The hyperactivation of this signaling has been identified in different cancer cells; and, it has been implicated in oncogenic transformation and cancer cell malignancy. Recent studies have argued the role of phosphoinositides in cancer cell dynamics, including actin cytoskeletal rearrangement at the plasma membrane and the organization of intracellular compartments. The focus of this review is to summarize the impact of the activities of phosphoinositide phosphatases on intracellular signaling related to cancer cell dynamics and to discuss how the abnormalities in the activities of the enzymes alter the levels of phosphoinositides in cancer cells.
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Affiliation(s)
- Takeshi Ijuin
- Division of Biochemistry, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki, Chu-o, Kobe 650-0017, Japan.
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41
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de Rubio RG, Ransom RF, Malik S, Yule DI, Anantharam A, Smrcka AV. Phosphatidylinositol 4-phosphate is a major source of GPCR-stimulated phosphoinositide production. Sci Signal 2018; 11:11/547/eaan1210. [PMID: 30206135 DOI: 10.1126/scisignal.aan1210] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Phospholipase C (PLC) enzymes hydrolyze the plasma membrane (PM) lipid phosphatidylinositol 4,5-bisphosphate (PI4,5P2) to generate the second messengers inositol trisphosphate (IP3) and diacylglycerol (DAG) in response to receptor activation in almost all mammalian cells. We previously found that stimulation of G protein-coupled receptors (GPCRs) in cardiac cells leads to the PLC-dependent hydrolysis of phosphatidylinositol 4-phosphate (PI4P) at the Golgi, a process required for the activation of nuclear protein kinase D (PKD) during cardiac hypertrophy. We hypothesized that GPCR-stimulated PLC activation leading to direct PI4P hydrolysis may be a general mechanism for DAG production. We measured GPCR activation-dependent changes in PM and Golgi PI4P pools in various cells using GFP-based detection of PI4P. Stimulation with various agonists caused a time-dependent reduction in PI4P-associated, but not PI4,5P2-associated, fluorescence at the Golgi and PM. Targeted depletion of PI4,5P2 from the PM before GPCR stimulation had no effect on the depletion of PM or Golgi PI4P, total inositol phosphate (IP) production, or PKD activation. In contrast, acute depletion of PI4P specifically at the PM completely blocked the GPCR-dependent production of IPs and activation of PKD but did not change the abundance of PI4,5P2 Acute depletion of Golgi PI4P had no effect on these processes. These data suggest that most of the PM PI4,5P2 pool is not involved in GPCR-stimulated phosphoinositide hydrolysis and that PI4P at the PM is responsible for the bulk of receptor-stimulated phosphoinositide hydrolysis and DAG production.
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Affiliation(s)
- Rafael Gil de Rubio
- Department of Pharmacology and Physiology, University of Rochester, Rochester, NY 14642, USA
| | - Richard F Ransom
- Department of Pharmacology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Sundeep Malik
- Department of Pharmacology and Physiology, University of Rochester, Rochester, NY 14642, USA
| | - David I Yule
- Department of Pharmacology and Physiology, University of Rochester, Rochester, NY 14642, USA
| | - Arun Anantharam
- Department of Pharmacology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Alan V Smrcka
- Department of Pharmacology and Physiology, University of Rochester, Rochester, NY 14642, USA. .,Department of Pharmacology, University of Michigan, Ann Arbor, MI 48109, USA
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42
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Zhang N, Prasad S, Huyghues Despointes CE, Young J, Kima PE. Leishmania parasitophorous vacuole membranes display phosphoinositides that create conditions for continuous Akt activation and a target for miltefosine in Leishmania infections. Cell Microbiol 2018; 20:e12889. [PMID: 29993167 DOI: 10.1111/cmi.12889] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Revised: 06/22/2018] [Accepted: 06/25/2018] [Indexed: 12/13/2022]
Abstract
Miltefosine is an important drug for the treatment of leishmaniasis; however, its mechanism of action is still poorly understood. In these studies, we tested the hypothesis that like in cancer cells, miltefosine's efficacy in leishmaniasis is due to its inhibition of Akt activation in host cells. We show using pharmacologic agents that block Akt activation by different mechanisms and also using an inducible knockdown approach that miltefosine loses its efficacy when its access to Akt1 is limited. Interestingly, limitation of Akt activation results in clearance of established Leishmania infections. We then show, using fluorophore-tagged probes that bind to phosphoinositides, that Leishmania parasitophorous vacuole membranes (LPVMs) display the relevant phosphoinositides to which Akt can be recruited and activated continuously. Taken together, we propose that the acquisition of PI(4) P and the display of PI (3,4)P2 on LPVMs initiate the machinery that supports continuous Akt activation and sensitivity to miltefosine.
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Affiliation(s)
- Naixin Zhang
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida, USA
| | - Samiksha Prasad
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida, USA
| | | | - Jeffrey Young
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida, USA
| | - Peter E Kima
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida, USA
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43
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Lu SM, Fairn GD. 7-Ketocholesterol impairs phagocytosis and efferocytosis via dysregulation of phosphatidylinositol 4,5-bisphosphate. Traffic 2018; 19:591-604. [PMID: 29693767 DOI: 10.1111/tra.12576] [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] [Received: 02/23/2017] [Revised: 04/16/2018] [Accepted: 04/18/2018] [Indexed: 12/27/2022]
Abstract
The plasma membrane is inhomogeneously organized containing both highly ordered and disordered nanodomains. 7-Ketocholesterol (7KC), an oxysterol formed from the nonenzymatic oxidation of cholesterol, is a potent disruptor of membrane order. Importantly, 7KC is a component of oxidized low-density lipoprotein and accumulates in macrophage and foam cells found in arterial plaques. Using a murine macrophage cell line, J774, we report that both IgG-mediated and phosphatidylserine-mediated phagocytic pathways are inhibited by the accumulation of 7KC. Examination of the well-studied Fcγ receptor pathway revealed that the cell surface receptor abundance and ligand binding are unaltered while downstream signaling and activation of spleen tyrosine kinase is not affected. However, while the recruitment of phospholipase Cγ1 was unaffected its apparent enzymatic activity was compromised resulting in sustained phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P2 ] levels and polymerized actin at the base of the phagocytic cup. Additionally, we found that 7KC prevented the activation of PLCβ downstream of the P2Y6 G-protein coupled receptor and that 7KC impaired PLCγ activity in response to a direct elevation of cytosolic calcium induced by ionomycin. Finally, we demonstrate that 7KC partly attenuates the activity of rapamycin recruitable constitutively active PLCβ3. Together, our results demonstrate that the accumulation of 7KC impairs macrophage function by altering PtdIns(4,5)P2 catabolism and, thus, impairing actin depolymerization required for the completion of phagocytosis.
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Affiliation(s)
- Stella M Lu
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada.,Keenan Research Centre for Biomedical Sciences, St. Michael's Hospital, Toronto, ON, Canada
| | - Gregory D Fairn
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada.,Keenan Research Centre for Biomedical Sciences, St. Michael's Hospital, Toronto, ON, Canada.,Department of Surgery and Institute of Medical Science, University of Toronto, Toronto, ON, Canada
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44
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Del Bel LM, Brill JA. Sac1, a lipid phosphatase at the interface of vesicular and nonvesicular transport. Traffic 2018; 19:301-318. [PMID: 29411923 DOI: 10.1111/tra.12554] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 02/02/2018] [Accepted: 02/02/2018] [Indexed: 12/14/2022]
Abstract
The lipid phosphatase Sac1 dephosphorylates phosphatidylinositol 4-phosphate (PI4P), thereby holding levels of this crucial membrane signaling molecule in check. Sac1 regulates multiple cellular processes, including cytoskeletal organization, membrane trafficking and cell signaling. Here, we review the structure and regulation of Sac1, its roles in cell signaling and development and its links to health and disease. Remarkably, many of the diverse roles attributed to Sac1 can be explained by the recent discovery of its requirement at membrane contact sites, where its consumption of PI4P is proposed to drive interorganelle transfer of other cellular lipids, thereby promoting normal lipid homeostasis within cells.
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Affiliation(s)
- Lauren M Del Bel
- Cell Biology Program, The Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Julie A Brill
- Cell Biology Program, The Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
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45
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Walpole GFW, Grinstein S, Westman J. The role of lipids in host-pathogen interactions. IUBMB Life 2018; 70:384-392. [PMID: 29573124 DOI: 10.1002/iub.1737] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Accepted: 02/27/2018] [Indexed: 11/07/2022]
Abstract
Innate immunity relies on the effective recognition and elimination of pathogenic microorganisms. This entails sequestration of pathogens into phagosomes that promptly acquire microbicidal and degradative properties. This complex series of events, which involve cytoskeletal reorganization, membrane remodeling and the activation of multiple enzymes, is orchestrated by lipid signaling. To overcome this immune response, intracellular pathogens acquired mechanisms to subvert phosphoinositide-mediated signaling and use host lipids, notably cholesterol, as nutrients. We present brief overviews of the role of phosphoinositides in phagosome formation and maturation as well as of cholesterol handling by host cells, and selected Salmonella, Shigella, Chlamydia and Mycobacterium tuberculosis to exemplify the mechanisms whereby intracellular pathogens co-opt lipid metabolism in host cells. © 2018 IUBMB Life, 70(5):384-392, 2018.
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Affiliation(s)
- Glenn F W Walpole
- Program in Cell Biology, The Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Biochemistry, University of Toronto, Ontario, Canada
| | - Sergio Grinstein
- Program in Cell Biology, The Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Biochemistry, University of Toronto, Ontario, Canada.,Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto, Ontario, Canada
| | - Johannes Westman
- Program in Cell Biology, The Hospital for Sick Children, Toronto, Ontario, Canada
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46
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Zewe JP, Wills RC, Sangappa S, Goulden BD, Hammond GR. SAC1 degrades its lipid substrate PtdIns4 P in the endoplasmic reticulum to maintain a steep chemical gradient with donor membranes. eLife 2018; 7:35588. [PMID: 29461204 PMCID: PMC5829913 DOI: 10.7554/elife.35588] [Citation(s) in RCA: 99] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Accepted: 02/13/2018] [Indexed: 12/22/2022] Open
Abstract
Gradients of PtdIns4P between organelle membranes and the endoplasmic reticulum (ER) are thought to drive counter-transport of other lipids via non-vesicular traffic. This novel pathway requires the SAC1 phosphatase to degrade PtdIns4P in a 'cis' configuration at the ER to maintain the gradient. However, SAC1 has also been proposed to act in 'trans' at membrane contact sites, which could oppose lipid traffic. It is therefore crucial to determine which mode SAC1 uses in living cells. We report that acute inhibition of SAC1 causes accumulation of PtdIns4P in the ER, that SAC1 does not enrich at membrane contact sites, and that SAC1 has little activity in 'trans', unless a linker is added between its ER-anchored and catalytic domains. The data reveal an obligate 'cis' activity of SAC1, supporting its role in non-vesicular lipid traffic and implicating lipid traffic more broadly in inositol lipid homeostasis and function.
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Affiliation(s)
- James P Zewe
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, United States
| | - Rachel C Wills
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, United States
| | - Sahana Sangappa
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, United States
| | - Brady D Goulden
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, United States
| | - Gerald Rv Hammond
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, United States
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47
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Gordon S, Plüddemann A. Macrophage Clearance of Apoptotic Cells: A Critical Assessment. Front Immunol 2018; 9:127. [PMID: 29441073 PMCID: PMC5797608 DOI: 10.3389/fimmu.2018.00127] [Citation(s) in RCA: 123] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Accepted: 01/16/2018] [Indexed: 12/22/2022] Open
Abstract
As the body continues to grow and age, it becomes essential to maintain a balance between living and dying cells. Macrophages and dendritic cells play a central role in discriminating among viable, apoptotic, and necrotic cells, as selective and efficient phagocytes, without inducing inappropriate inflammation or immune responses. A great deal has been learnt concerning clearance receptors for modified and non-self-ligands on potential targets, mediating their eventual uptake, disposal, and replacement. In this essay, we assess current understanding of the phagocytic recognition of apoptotic cells within their tissue environment; we conclude that efferocytosis constitutes a more complex process than simply removal of corpses, with regulatory interactions between the target and effector cells, which determine the outcome of this homeostatic process.
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Affiliation(s)
- Siamon Gordon
- College of Medicine, Graduate Institute of Biomedical Sciences, Chang Gung University, Taoyuan City, Taiwan.,Sir William Dunn School of Pathology, University of Oxford, Oxford, United Kingdom
| | - Annette Plüddemann
- Nuffield Department of Primary Care Health Sciences, University of Oxford, Oxford, United Kingdom
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48
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Minogue S. The Many Roles of Type II Phosphatidylinositol 4-Kinases in Membrane Trafficking: New Tricks for Old Dogs. Bioessays 2017; 40. [PMID: 29280156 DOI: 10.1002/bies.201700145] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Revised: 11/09/2017] [Indexed: 12/12/2022]
Abstract
The type II phosphatidylinositol 4-kinases (PI4KIIs) produce the lipid phosphatidylinositol 4-phosphate (PtdIns4P) and participate in a confusing variety of membrane trafficking and signaling roles. This review argues that both historical and contemporary evidence supports the function of the PI4KIIs in numerous trafficking pathways, and that the key to understanding the enzymatic regulation is through membrane interaction and the intrinsic membrane environment. By summarizing new research and examining the trafficking roles of the PI4KIIs in the context of recently solved molecular structures, I highlight how mechanisms of PI4KII function and regulation are providing insights into the development of cancer and in neurological disease. I present an integrated view connecting the cell biology, molecular regulation, and roles in whole animal systems of these increasingly important proteins.
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Affiliation(s)
- Shane Minogue
- Lipid and Membrane Biology Group, UCL Division of Medicine, Royal Free Campus, University College London, London, NW3 2PF, UK
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49
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Jeschke A, Haas A. Sequential actions of phosphatidylinositol phosphates regulate phagosome-lysosome fusion. Mol Biol Cell 2017; 29:452-465. [PMID: 29237821 PMCID: PMC6014173 DOI: 10.1091/mbc.e17-07-0464] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Revised: 11/14/2017] [Accepted: 12/08/2017] [Indexed: 02/05/2023] Open
Abstract
Phagosome-with-lysosome fusion comprises subreactions with differential lipid requirements: PI(4)P is required during and after phagosome-to-lysosome tethering, and PI(3)P is required after tethering. Moreover, PI(4)P serves to anchor to (phago)lysosome membranes Arl8 and HOPS, whereas PI(3)P contributes to membrane binding of HOPS only. Phagosomes mature into phagolysosomes by sequential fusion with early endosomes, late endosomes, and lysosomes. Phagosome-with-lysosome fusion (PLF) results in the delivery of lysosomal hydrolases into phagosomes and in digestion of the cargo. The machinery that drives PLF has been little investigated. Using a cell-free system, we recently identified the phosphoinositide lipids (PIPs) phosphatidylinositol 3-phosphate (PI(3)P) and phosphatidylinositol 4-phosphate (PI(4)P) as regulators of PLF. We now report the identification and the PIP requirements of four distinct subreactions of PLF. Our data show that (i) PI(3)P and PI(4)P are dispensable for the disassembly and activation of (phago)lysosomal soluble N-ethylmaleimide-sensitive factor attachment protein receptors, that (ii) PI(3)P is required only after the tethering step, and that (iii) PI(4)P is required during and after tethering. Moreover, our data indicate that PI(4)P is needed to anchor Arl8 (Arf-like GTPase 8) and its effector homotypic fusion/vacuole protein sorting complex (HOPS) to (phago)lysosome membranes, whereas PI(3)P is required for membrane association of HOPS only. Our study provides a first link between PIPs and established regulators of membrane fusion in late endocytic trafficking.
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Affiliation(s)
- Andreas Jeschke
- Cell Biology Institute, University of Bonn, 53121 Bonn, Germany
| | - Albert Haas
- Cell Biology Institute, University of Bonn, 53121 Bonn, Germany
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50
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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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