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Ikeda Y, Davis MI, Sumita K, Zheng Y, Kofuji S, Sasaki M, Hirota Y, Pragani R, Shen M, Boxer MB, Takeuchi K, Senda T, Simeonov A, Sasaki AT. Multimodal action of KRP203 on phosphoinositide kinases in vitro and in cells. Biochem Biophys Res Commun 2023; 679:116-121. [PMID: 37683456 PMCID: PMC10559341 DOI: 10.1016/j.bbrc.2023.08.050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2023] [Accepted: 08/22/2023] [Indexed: 09/10/2023]
Abstract
Increased phosphoinositide signaling is commonly associated with cancers. While "one-drug one-target" has been a major drug discovery strategy for cancer therapy, a "one-drug multi-targets" approach for phosphoinositide enzymes has the potential to offer a new therapeutic approach. In this study, we sought a new way to target phosphoinositides metabolism. Using a high-throughput phosphatidylinositol 5-phosphate 4-kinase-alpha (PI5P4Kα) assay, we have identified that the immunosuppressor KRP203/Mocravimod induces a significant perturbation in phosphoinositide metabolism in U87MG glioblastoma cells. Despite high sequence similarity of PI5P4K and PI4K isozymes, in vitro kinase assays showed that KRP203 activates some (e.g., PI5P4Kα, PI4KIIβ) while inhibiting other phosphoinositide kinases (e.g., PI5P4Kβ, γ, PI4KIIα, class I PI3K-p110α, δ, γ). Furthermore, KRP203 enhances PI3P5K/PIKFYVE's substrate selectivity for phosphatidylinositol (PI) while preserving its selectivity for PI(3)P. At cellular levels, 3 h of KRP203 treatment induces a prominent increase of PI(3)P and moderate increase of PI(5)P, PI(3,5)P2, and PI(3,4,5)P3 levels in U87MG cells. Collectively, the finding of multimodal activity of KRP203 towards multi-phosphoinositide kinases may open a novel basis to modulate cellular processes, potentially leading to more effective treatments for diseases associated with phosphoinositide signaling pathways.
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Affiliation(s)
- Yoshiki Ikeda
- Division of Hematology and Oncology, Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, 45267, USA; Institute for Integrated Cell-Material Sciences, Kyoto University, Sakyo-ku, Kyoto, 606-8501, Japan
| | - Mindy I Davis
- National Center for Advancing Translational Sciences (NCATS), National Institutes of Health (NIH), Rockville, MD, 20850, USA
| | - Kazutaka Sumita
- Division of Hematology and Oncology, Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, 45267, USA; Department of Endovascular Surgery, Tokyo Medical and Dental University, Tokyo, 113-8510, Japan
| | - Yuxiang Zheng
- Meyer Cancer Center, Weill Cornell Medicine, New York, NY, 10007, USA
| | - Satoshi Kofuji
- Division of Hematology and Oncology, Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, 45267, USA; Department of Developmental and Regenerative Biology, Medical Research Institute, Tokyo Medical and Dental University (TMDU), Tokyo, 113-8510, Japan
| | - Mika Sasaki
- Division of Hematology and Oncology, Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, 45267, USA
| | - Yoshihisa Hirota
- Division of Hematology and Oncology, Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, 45267, USA; Department of Bioscience and Engineering, College of Systems Engineering and Science, Shibaura Institute of Technology, Minuma-ku, Saitama, 337-8570, Japan
| | - Rajan Pragani
- National Center for Advancing Translational Sciences (NCATS), National Institutes of Health (NIH), Rockville, MD, 20850, USA
| | - Min Shen
- National Center for Advancing Translational Sciences (NCATS), National Institutes of Health (NIH), Rockville, MD, 20850, USA
| | - Matthew B Boxer
- National Center for Advancing Translational Sciences (NCATS), National Institutes of Health (NIH), Rockville, MD, 20850, USA
| | - Koh Takeuchi
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, 113-0033, Japan
| | - Toshiya Senda
- Structural Biology Research Center, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki, 305-0801, Japan; Department of Accelerator Science, School of High Energy Accelerator Science, The Graduate University for Advanced Studies), Tsukuba, Ibaraki, 305-0801, Japan; Faculty of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8572, Japan
| | - Anton Simeonov
- National Center for Advancing Translational Sciences (NCATS), National Institutes of Health (NIH), Rockville, MD, 20850, USA
| | - Atsuo T Sasaki
- Division of Hematology and Oncology, Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, 45267, USA; Institute for Advanced Biosciences, Keio University, Tsuruoka, 997-0052, Japan; Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, OH, 45267, USA; Department of Neurosurgery, Brain Tumor Center at UC Gardner Neuroscience Institute, Cincinnati, OH, 45267, USA; Department of Clinical and Molecular Genetics, Hiroshima University Hospital, Hiroshima, 734-8551, Japan.
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Abstract
Phosphoinositides (PIs) are phospholipids derived from phosphatidylinositol. PIs are regulated via reversible phosphorylation, which is directed by the opposing actions of PI kinases and phosphatases. PIs constitute a minor fraction of the total cellular lipid pool but play pleiotropic roles in multiple aspects of cell biology. Genetic mutations of PI regulatory enzymes have been identified in rare congenital developmental syndromes, including ciliopathies, and in numerous human diseases, such as cancer and metabolic and neurological disorders. Accordingly, PI regulatory enzymes have been targeted in the design of potential therapeutic interventions for human diseases. Recent advances place PIs as central regulators of membrane dynamics within functionally distinct subcellular compartments. This brief review focuses on the emerging role PIs play in regulating cell signaling within the primary cilium and in directing transfer of molecules at interorganelle membrane contact sites and identifies new roles for PIs in subcellular spaces.
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Affiliation(s)
- Elizabeth Michele Davies
- Cancer Program, Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Victoria 3800, Australia
| | - Christina Anne Mitchell
- Cancer Program, Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Victoria 3800, Australia
| | - Harald Alfred Stenmark
- Department of Molecular Cell Biology, Institute for Cancer Research. The Norwegian Radium Hospital, Montebello, N-0379 Oslo, Norway
- Centre for Cancer Cell Reprogramming, Faculty of Medicine, University of Oslo, Montebello, N-0379 Oslo, Norway
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3
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Wen T, Thapa N, Cryns VL, Anderson RA. Regulation of Phosphoinositide Signaling by Scaffolds at Cytoplasmic Membranes. Biomolecules 2023; 13:1297. [PMID: 37759697 PMCID: PMC10526805 DOI: 10.3390/biom13091297] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 08/21/2023] [Accepted: 08/22/2023] [Indexed: 09/29/2023] Open
Abstract
Cytoplasmic phosphoinositides (PI) are critical regulators of the membrane-cytosol interface that control a myriad of cellular functions despite their low abundance among phospholipids. The metabolic cycle that generates different PI species is crucial to their regulatory role, controlling membrane dynamics, vesicular trafficking, signal transduction, and other key cellular events. The synthesis of phosphatidylinositol (3,4,5)-triphosphate (PI3,4,5P3) in the cytoplamic PI3K/Akt pathway is central to the life and death of a cell. This review will focus on the emerging evidence that scaffold proteins regulate the PI3K/Akt pathway in distinct membrane structures in response to diverse stimuli, challenging the belief that the plasma membrane is the predominant site for PI3k/Akt signaling. In addition, we will discuss how PIs regulate the recruitment of specific scaffolding complexes to membrane structures to coordinate vesicle formation, fusion, and reformation during autophagy as well as a novel lysosome repair pathway.
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Affiliation(s)
- Tianmu Wen
- School of Medicine and Public Health, University of Wisconsin-Madison, 1111 Highland Avenue, Madison, WI 53705, USA; (T.W.); (N.T.)
| | - Narendra Thapa
- School of Medicine and Public Health, University of Wisconsin-Madison, 1111 Highland Avenue, Madison, WI 53705, USA; (T.W.); (N.T.)
| | - Vincent L. Cryns
- Department of Medicine, University of Wisconsin Carbone Cancer Center, School of Medicine and Public Health, University of Wisconsin-Madison, 1111 Highland Avenue, Madison, WI 53705, USA
| | - Richard A. Anderson
- School of Medicine and Public Health, University of Wisconsin-Madison, 1111 Highland Avenue, Madison, WI 53705, USA; (T.W.); (N.T.)
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Karabiyik C, Rubinsztein DC. Protocol for determining the regulation of lipid kinases and changes in phospholipids in vitro. STAR Protoc 2021; 2:100926. [PMID: 34766030 PMCID: PMC8571518 DOI: 10.1016/j.xpro.2021.100926] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The regulation of lipid kinases has remained elusive given the difficulties of assessing changes in lipid levels. Here, we describe the isolation of protein and lipid kinases to determine the regulation of lipid kinases in vitro. This can be followed by analysis of effects of regulators on lipid kinase-mediated changes in phospholipids without the use of radioactivity, with a specific focus on PI(5)P generation by the enzyme PIKfyve. For complete details on the use and execution of this protocol, please refer to Karabiyik et al. (2021).
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Affiliation(s)
- Cansu Karabiyik
- Department of Medical Genetics, Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, UK
- UK Dementia Research Institute, Cambridge, UK
- Mortimer B. Zuckerman Mind Brain and Behavior Institute, Columbia University, 3227 Broadway, Manhattan, NY 10027, USA
| | - David C. Rubinsztein
- Department of Medical Genetics, Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, UK
- UK Dementia Research Institute, Cambridge, UK
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5
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Ionization properties of monophosphoinositides in mixed model membranes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2021; 1863:183692. [PMID: 34265284 DOI: 10.1016/j.bbamem.2021.183692] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 06/29/2021] [Accepted: 07/01/2021] [Indexed: 12/28/2022]
Abstract
Phosphoinositides are found in low concentration in cellular membranes but perform numerous functions such as signaling, membrane trafficking, protein recruitment and modulation of protein activity. Spatiotemporal regulation by enzymes that phosphorylate and dephosphorylate the inositol ring results in the production of seven distinct and functionally diverse derivatives. Ionization properties of the phosphorylated headgroups of anionic lipids have been shown to impact how they interact with proteins and lipids in the membrane. While the ionization properties of the three bis and one tris phosphorylated forms have been studied in physiologically relevant model membranes, that of the monophosphorylated forms (i.e., phosphatidylinositol-3-phosphate (PI3P), phosphatidylinositol-4-phosphate (PI4P), phosphatidylinositol-5-phosphate (PI5P)) has received less attention. Here, we used 31P MAS NMR to determine the charge of 5 mol% of the monophosphorylated derivatives in pure dioleoylphosphatidylcholine (DOPC) and DOPC/dioleoylphosphatidylethanolamine (DOPE) bilayers as a function of pH. We find that PI3P, PI4P and PI5P each have unique pKa2 values in a DOPC bilayer, and each is reduced in DOPC/DOPE model membranes through the interaction of their headgroups with DOPE according to the electrostatic-hydrogen bond switch model. In this study, using model membranes mimicking the plasma membrane (inner leaflet), Golgi, nuclear membrane, and endosome (outer leaflet), we show that PI3P, PI4P or PI5P maximize their charge at neutral pH. Our results shed light on the electrostatics of the monophosphorylated headgroups of PI3P, PI4P, and PI5P and form the basis of their intracellular functions.
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Karabiyik C, Vicinanza M, Son SM, Rubinsztein DC. Glucose starvation induces autophagy via ULK1-mediated activation of PIKfyve in an AMPK-dependent manner. Dev Cell 2021; 56:1961-1975.e5. [PMID: 34107300 DOI: 10.1016/j.devcel.2021.05.010] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Revised: 02/24/2021] [Accepted: 05/12/2021] [Indexed: 12/11/2022]
Abstract
Autophagy is an essential catabolic process induced to provide cellular energy sources in response to nutrient limitation through the activation of kinases, like AMP-activated protein kinase (AMPK) and ULK1. Although glucose starvation induces autophagy, the exact mechanism underlying this signaling has yet to be elucidated. Here, we reveal a role for ULK1 in non-canonical autophagy signaling using diverse cell lines. ULK1 activated by AMPK during glucose starvation phosphorylates the lipid kinase PIKfyve on S1548, thereby increasing its activity and the synthesis of the phospholipid PI(5)P without changing the levels of PI(3,5)P2. ULK1-mediated activation of PIKfyve enhances the formation of PI(5)P-containing autophagosomes upon glucose starvation, resulting in an increase in autophagy flux. Phospho-mimic PIKfyve S1548D drives autophagy upregulation and lowers autophagy substrate levels. Our study has identified how ULK1 upregulates autophagy upon glucose starvation and induces the formation of PI(5)P-containing autophagosomes by activating PIKfyve.
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Affiliation(s)
- Cansu Karabiyik
- Department of Medical Genetics, Cambridge Institute for Medical Research, University of Cambridge, Cambridge, UK; UK Dementia Research Institute, Cambridge, UK
| | - Mariella Vicinanza
- Department of Medical Genetics, Cambridge Institute for Medical Research, University of Cambridge, Cambridge, UK; UK Dementia Research Institute, Cambridge, UK
| | - Sung Min Son
- Department of Medical Genetics, Cambridge Institute for Medical Research, University of Cambridge, Cambridge, UK; UK Dementia Research Institute, Cambridge, UK
| | - David C Rubinsztein
- Department of Medical Genetics, Cambridge Institute for Medical Research, University of Cambridge, Cambridge, UK; UK Dementia Research Institute, Cambridge, UK.
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Claude-Taupin A, Morel E. Phosphoinositides: Functions in autophagy-related stress responses. Biochim Biophys Acta Mol Cell Biol Lipids 2021; 1866:158903. [PMID: 33578048 DOI: 10.1016/j.bbalip.2021.158903] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2020] [Revised: 01/29/2021] [Accepted: 02/06/2021] [Indexed: 01/02/2023]
Abstract
Phosphoinositides are key lipids in eukaryotes, regulating organelles' identity and function. Their synthesis and turnover require specific phosphorylation/dephosphorylation events that are ensured by dedicated lipid kinases and phosphatases, which modulate the structure of the inositol ring by adding or removing phosphates on positions 3, 4 or 5. Beside their implication in intracellular signalization and cytoskeleton dynamics, phosphoinositides are essential for vesicular transport along intracellular trafficking routes, by providing molecular scaffolds to membrane related events such as budding, fission or fusion. Robust and detailed literature demonstrated that some members of the phosphoinositides family are crucial for the autophagy pathway, acting as fine tuners and regulators. In this review, we discuss the known functions of phosphoinositides in autophagy canonical processes, such as during autophagosome formation, as well as the importance of phosphoinositides in organelle-based processes directly connected to the autophagic machinery, such as endosomal dynamics, ciliogenesis and innate immunity.
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Affiliation(s)
- Aurore Claude-Taupin
- Institut Necker Enfants-Malades (INEM), INSERM U1151-CNRS UMR 8253, Université de Paris, Paris, France
| | - Etienne Morel
- Institut Necker Enfants-Malades (INEM), INSERM U1151-CNRS UMR 8253, Université de Paris, Paris, France.
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Xu C, Wan Z, Shaheen S, Wang J, Yang Z, Liu W. A PI(4,5)P2-derived "gasoline engine model" for the sustained B cell receptor activation. Immunol Rev 2020; 291:75-90. [PMID: 31402506 DOI: 10.1111/imr.12775] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2019] [Revised: 05/08/2019] [Accepted: 05/09/2019] [Indexed: 12/14/2022]
Abstract
To efficiently initiate activation responses against rare ligands in the microenvironment, lymphocytes employ sophisticated mechanisms involving signaling amplification. Recently, a signaling amplification mechanism initiated from phosphatidylinositol (PI) 4, 5-biphosphate [PI(4,5)P2] hydrolysis and synthesis for sustained B cell activation has been reported. Antigen and B cell receptor (BCR) recognition triggered the prompt reduction of PI(4,5)P2 density within the BCR microclusters, which led to the positive feedback for the synthesis of PI(4,5)P2 outside of the BCR microclusters. At single molecule level, the diffusion of PI(4,5)P2 was slow, allowing for the maintenance of a PI(4,5)P2 density gradient between the inside and outside of the BCR microclusters and the persistent supply of PI(4,5)P2 from outside to inside of the BCR microclusters. Here, we review studies that have contributed to uncovering the molecular mechanisms of PI(4,5)P2-derived signaling amplification model. Based on these studies, we proposed a "gasoline engine model" in which the activation of B cell signaling inside the microclusters is similar to the working principle of burning gasoline within the engine chamber of a gasoline engine. We also discuss the evidences showing the potential universality of this model and future prospects.
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Affiliation(s)
- Chenguang Xu
- Center for Life Sciences, MOE Key Laboratory of Protein Sciences, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Beijing Key Lab for Immunological Research on Chronic Diseases, School of Life Sciences, Institute for Immunology, Tsinghua University, Beijing, China
| | - Zhengpeng Wan
- Center for Life Sciences, MOE Key Laboratory of Protein Sciences, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Beijing Key Lab for Immunological Research on Chronic Diseases, School of Life Sciences, Institute for Immunology, Tsinghua University, Beijing, China
| | - Samina Shaheen
- Center for Life Sciences, MOE Key Laboratory of Protein Sciences, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Beijing Key Lab for Immunological Research on Chronic Diseases, School of Life Sciences, Institute for Immunology, Tsinghua University, Beijing, China
| | - Jing Wang
- Center for Life Sciences, MOE Key Laboratory of Protein Sciences, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Beijing Key Lab for Immunological Research on Chronic Diseases, School of Life Sciences, Institute for Immunology, Tsinghua University, Beijing, China
| | - Zhiyong Yang
- Cardiovascular Research Institute, University of California San Francisco, San Francisco, California
| | - Wanli Liu
- Center for Life Sciences, MOE Key Laboratory of Protein Sciences, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Beijing Key Lab for Immunological Research on Chronic Diseases, School of Life Sciences, Institute for Immunology, Tsinghua University, Beijing, China
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Severe Consequences of SAC3/FIG4 Phosphatase Deficiency to Phosphoinositides in Patients with Charcot-Marie-Tooth Disease Type-4J. Mol Neurobiol 2019; 56:8656-8667. [PMID: 31313076 DOI: 10.1007/s12035-019-01693-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Accepted: 07/01/2019] [Indexed: 01/26/2023]
Abstract
Charcot-Marie-Tooth disease type-4J (CMT4J), an autosomal recessively inherited peripheral neuropathy characterized by neuronal degeneration, segmental demyelination, and limb muscle weakness, is caused by compound heterozygous mutations in the SAC3/FIG4 gene, resulting in SAC3/FIG4 protein deficiency. SAC3/FIG4 is a phosphatase that not only turns over PtdIns(3,5)P2 to PtdIns3P but also promotes PtdIns(3,5)P2 synthesis by activating the PIKFYVE kinase that also makes PtdIns5P. Whether CMT4J patients have alterations in PtdIns(3,5)P2, PtdIns5P or in other phosphoinositides (PIs), and if yes, in what direction these changes might be, has never been examined. We performed PI profiling in primary fibroblasts from a cohort of CMT4J patients. Subsequent to myo-[2-3H]inositol cell labeling to equilibrium, steady-state levels of PIs were quantified by HPLC under conditions concurrently detecting PtdIns5P, PtdIns(3,5)P2, and the other PIs. Immunoblotting verified SAC3/FIG4 depletion in CMT4J fibroblasts. Compared to normal human controls (n = 9), both PtdIns(3,5)P2 and PtdIns5P levels were significantly decreased in CMT4J fibroblasts (n = 13) by 36.4 ± 3.6% and 43.1 ± 4.4%, respectively (p < 0.0001). These reductions were independent of patients' gender or disease onset. Although mean values for PtdIns3P in the CMT4J cohort remained unchanged, there were high variations in PtdIns3P among individual patients. Aberrant endolysosomal vacuoles, typically seen under PtdIns(3,5)P2 reduction, were apparent but not in fibroblasts from all patients. The subset of patients without aberrant vacuoles exhibited especially low PtdIns3P levels. Concomitant decreases in PtdIns5P and PtdIns(3,5)P2 and the link between PtdIns3P levels and cellular vacuolization are novel insights shedding further light into the molecular determinants in CMT4J polyneuropathy.
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10
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Ghosh A, Sharma S, Shinde D, Ramya V, Raghu P. A novel mass assay to measure phosphatidylinositol-5-phosphate from cells and tissues. Biosci Rep 2019; 39:BSR20192502. [PMID: 31652444 PMCID: PMC6822513 DOI: 10.1042/bsr20192502] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Revised: 09/19/2019] [Accepted: 09/27/2019] [Indexed: 12/23/2022] Open
Abstract
Phosphatidylinositol-5-phosphate (PI5P) is a low abundance lipid proposed to have functions in cell migration, DNA damage responses, receptor trafficking and insulin signalling in metazoans. However, studies of PI5P function are limited by the lack of scalable techniques to quantify its level from cells and tissues in multicellular organisms. Currently, PI5P measurement requires the use of radionuclide labelling approaches that are not easily applicable in tissues or in vivo samples. In the present study, we describe a simple and reliable, non-radioactive mass assay to measure total PI5P levels from cells and tissues of Drosophila, a genetically tractable multicellular model. We use heavy oxygen-labelled ATP (18O-ATP) to label PI5P from tissue extracts while converting it into PI(4,5)P2 using an in vitro kinase reaction. The product of this reaction can be selectively detected and quantified with high sensitivity using a liquid chromatography-tandem mass spectrometry (LC-MS/MS) platform. Further, using this method, we capture and quantify the unique acyl chain composition of PI5P from Drosophila cells and tissues. Finally, we demonstrate the use of this technique to quantify elevations in PI5P levels, from Drosophila larval tissues and cultured cells depleted of phosphatidylinositol 5 phosphate 4-kinase (PIP4K), that metabolizes PI5P into PI(4,5)P2 thus regulating its levels. Thus, we demonstrate the potential of our method to quantify PI5P levels with high sensitivity from cells and tissues of multicellular organisms thus accelerating understanding of PI5P functions in vivo.
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Affiliation(s)
- Avishek Ghosh
- National Centre for Biological Sciences, TIFR-GKVK Campus, Bellary Road, Bangalore 560065, India
| | - Sanjeev Sharma
- National Centre for Biological Sciences, TIFR-GKVK Campus, Bellary Road, Bangalore 560065, India
| | - Dhananjay Shinde
- National Centre for Biological Sciences, TIFR-GKVK Campus, Bellary Road, Bangalore 560065, India
| | - Visvanathan Ramya
- National Centre for Biological Sciences, TIFR-GKVK Campus, Bellary Road, Bangalore 560065, India
| | - Padinjat Raghu
- National Centre for Biological Sciences, TIFR-GKVK Campus, Bellary Road, Bangalore 560065, India
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11
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Phosphatidylinositol 5 Phosphate (PI5P): From Behind the Scenes to the Front (Nuclear) Stage. Int J Mol Sci 2019; 20:ijms20092080. [PMID: 31035587 PMCID: PMC6539119 DOI: 10.3390/ijms20092080] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2019] [Revised: 04/20/2019] [Accepted: 04/23/2019] [Indexed: 12/11/2022] Open
Abstract
Phosphatidylinositol (PI)-related signaling plays a pivotal role in many cellular aspects, including survival, cell proliferation, differentiation, DNA damage, and trafficking. PI is the core of a network of proteins represented by kinases, phosphatases, and lipases which are able to add, remove or hydrolyze PI, leading to different phosphoinositide products. Among the seven known phosphoinositides, phosphatidylinositol 5 phosphate (PI5P) was the last to be discovered. PI5P presence in cells is very low compared to other PIs. However, much evidence collected throughout the years has described the role of this mono-phosphoinositide in cell cycles, stress response, T-cell activation, and chromatin remodeling. Interestingly, PI5P has been found in different cellular compartments, including the nucleus. Here, we will review the nuclear role of PI5P, describing how it is synthesized and regulated, and how changes in the levels of this rare phosphoinositide can lead to different nuclear outputs.
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12
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Abstract
Polyphosphoinositides (PPIn) are essential signaling phospholipids that make remarkable contributions to the identity of all cellular membranes and signaling cascades in mammalian cells. They exert regulatory control over membrane homeostasis via selective interactions with cellular proteins at the membrane–cytoplasm interface. This review article briefly summarizes our current understanding of the key roles that PPIn play in orchestrating and regulating crucial electrical and chemical signaling events in mammalian neurons and the significant neuro-pathophysiological conditions that arise following alterations in their metabolism.
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Affiliation(s)
- Eamonn James Dickson
- Department Physiology and Membrane Biology, University of California, Davis, CA, 95616, USA
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Sbrissa D, Naisan G, Ikonomov OC, Shisheva A. Apilimod, a candidate anticancer therapeutic, arrests not only PtdIns(3,5)P2 but also PtdIns5P synthesis by PIKfyve and induces bafilomycin A1-reversible aberrant endomembrane dilation. PLoS One 2018; 13:e0204532. [PMID: 30240452 PMCID: PMC6150535 DOI: 10.1371/journal.pone.0204532] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2018] [Accepted: 09/10/2018] [Indexed: 01/02/2023] Open
Abstract
PIKfyve, an evolutionarily conserved kinase synthesizing PtdIns5P and PtdIns(3,5)P2, is crucial for mammalian cell proliferation and viability. Accordingly, PIKfyve inhibitors are now in clinical trials as anti-cancer drugs. Among those, apilimod is the most promising, yet its potency to inhibit PIKfyve and affect endomembrane homeostasis is only partially characterized. We demonstrate here for the first time that apilimod powerfully inhibited in vitro synthesis of PtdIns5P along with that of PtdIns(3,5)P2. HPLC-based resolution of intracellular phosphoinositides (PIs) revealed that apilimod triggered a marked reduction of both lipids in the context of intact cells. Notably, there was also a profound rise in PtdIns3P resulting from arrested PtdIns3P consumption for PtdIns(3,5)P2 synthesis. As typical for PIKfyve inhibition and the concomitant PtdIns(3,5)P2 reduction, apilimod induced the appearance of dilated endomembrane structures in the form of large translucent cytoplasmic vacuoles. Remarkably, bafilomycin A1 (BafA1) fully reversed the aberrant cell phenotype back to normal and completely precluded the appearance of cytoplasmic vacuoles when added prior to apilimod. Inspection of the PI profiles ruled out restoration of the reduced PtdIns(3,5)P2 pool as a molecular mechanism underlying BafA1 rescue. Rather, we found that BafA1 markedly attenuated the PtdIns3P elevation under PIKfyve inhibition. This was accompanied by profoundly decreased endosomal recruitment of fusogenic EEA1. Together, our data demonstrate that apilimod inhibits not only PtdIns(3,5)P2 but also PtdIns5P synthesis and that the cytoplasmic vacuolization triggered by the inhibitor is precluded or reversed by BafA1 through a mechanism associated, in part, with reduction in both PtdIns3P levels and EEA1 membrane recruitment.
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Affiliation(s)
- Diego Sbrissa
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan, United States of America
| | - Ghassan Naisan
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan, United States of America
| | - Ognian C. Ikonomov
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan, United States of America
| | - Assia Shisheva
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan, United States of America
- * E-mail:
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14
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Morioka S, Nigorikawa K, Okada E, Tanaka Y, Kasuu Y, Yamada M, Kofuji S, Takasuga S, Nakanishi H, Sasaki T, Hazeki K. TMEM55a localizes to macrophage phagosomes to downregulate phagocytosis. J Cell Sci 2018; 131:jcs.213272. [PMID: 29378918 DOI: 10.1242/jcs.213272] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Accepted: 01/22/2018] [Indexed: 01/29/2023] Open
Abstract
TMEM55a (also known as PIP4P2) is an enzyme that dephosphorylates the phosphatidylinositol (PtdIns) PtdIns(4,5)P2 to form PtdIns(5)P in vitro However, the in vivo conversion of the polyphosphoinositide into PtdIns(5)P by the phosphatase has not yet been demonstrated, and the role of TMEM55a remains poorly understood. Here, we found that mouse macrophages (Raw264.7) deficient in TMEM55a showed an increased engulfment of large particles without affecting the phagocytosis of Escherichia coli Transfection of a bacterial phosphatase with similar substrate specificity to TMEM55a, namely IpgD, into Raw264.7 cells inhibited the engulfment of IgG-erythrocytes in a manner dependent on its phosphatase activity. In contrast, cells transfected with PIP4K2a, which catalyzes PtdIns(4,5)P2 production from PtdIns(5)P, increased phagocytosis. Fluorescent TMEM55a transfected into Raw264.7 cells was found to mostly localize to the phagosome. The accumulation of PtdIns(4,5)P2, PtdIns(3,4,5)P3 and F-actin on the phagocytic cup was increased in TMEM55a-deficient cells, as monitored by live-cell imaging. Phagosomal PtdIns(5)P was decreased in the knockdown cells, but the augmentation of phagocytosis in these cells was unaffected by the exogenous addition of PtdIns(5)P. Taken together, these results suggest that TMEM55a negatively regulates the phagocytosis of large particles by reducing phagosomal PtdIns(4,5)P2 accumulation during cup formation.
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Affiliation(s)
- Shin Morioka
- Graduate School of Biomedical & Health Sciences, Hiroshima University, Hiroshima 734-8553, Japan
| | - Kiyomi Nigorikawa
- Graduate School of Biomedical & Health Sciences, Hiroshima University, Hiroshima 734-8553, Japan
| | - Eri Okada
- Graduate School of Biomedical & Health Sciences, Hiroshima University, Hiroshima 734-8553, Japan
| | - Yoshimasa Tanaka
- Graduate School of Biomedical & Health Sciences, Hiroshima University, Hiroshima 734-8553, Japan
| | - Yoshihiro Kasuu
- Graduate School of Biomedical & Health Sciences, Hiroshima University, Hiroshima 734-8553, Japan
| | - Miho Yamada
- Graduate School of Biomedical & Health Sciences, Hiroshima University, Hiroshima 734-8553, Japan
| | - Satoshi Kofuji
- Graduate School of Biomedical & Health Sciences, Hiroshima University, Hiroshima 734-8553, Japan
| | - Shunsuke Takasuga
- Department of Pathology and Immunology, Akita University School of Medicine, Akita 010-8543, Japan
| | - Hiroki Nakanishi
- Research Center for Biosignal, Akita University School of Medicine, Akita 010-8543, Japan
| | - Takehiko Sasaki
- Department of Pathology and Immunology, Akita University School of Medicine, Akita 010-8543, Japan
| | - Kaoru Hazeki
- Graduate School of Biomedical & Health Sciences, Hiroshima University, Hiroshima 734-8553, Japan
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15
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Tronchere H, Cinato M, Timotin A, Guitou L, Villedieu C, Thibault H, Baetz D, Payrastre B, Valet P, Parini A, Kunduzova O, Boal F. Inhibition of PIKfyve prevents myocardial apoptosis and hypertrophy through activation of SIRT3 in obese mice. EMBO Mol Med 2018; 9:770-785. [PMID: 28396567 PMCID: PMC5452048 DOI: 10.15252/emmm.201607096] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
PIKfyve is an evolutionarily conserved lipid kinase that regulates pleiotropic cellular functions. Here, we identify PIKfyve as a key regulator of cardiometabolic status and mitochondrial integrity in chronic diet‐induced obesity. In vitro, we show that PIKfyve is critical for the control of mitochondrial fragmentation and hypertrophic and apoptotic responses to stress. We also provide evidence that inactivation of PIKfyve by the selective inhibitor STA suppresses excessive mitochondrial ROS production and apoptosis through a SIRT3‐dependent pathway in cardiomyoblasts. In addition, we report that chronic STA treatment improves cardiometabolic profile in a mouse model of cardiomyopathy linked to obesity. We provide evidence that PIKfyve inhibition reverses obesity‐induced cardiac mitochondrial damage and apoptosis by activating SIRT3. Furthermore, treatment of obese mice with STA improves left ventricular function and attenuates cardiac hypertrophy. In contrast, STA is not able to reduce isoproterenol‐induced cardiac hypertrophy in SIRT3.KO mice. Altogether, these results unravel a novel role for PIKfyve in obesity‐associated cardiomyopathy and provide a promising therapeutic strategy to combat cardiometabolic complications in obesity.
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Affiliation(s)
- Helene Tronchere
- INSERM U1048 I2MC, Toulouse, Cedex 4, France.,Université Paul Sabatier, Toulouse, France
| | - Mathieu Cinato
- INSERM U1048 I2MC, Toulouse, Cedex 4, France.,Université Paul Sabatier, Toulouse, France
| | - Andrei Timotin
- INSERM U1048 I2MC, Toulouse, Cedex 4, France.,Université Paul Sabatier, Toulouse, France
| | - Laurie Guitou
- INSERM U1048 I2MC, Toulouse, Cedex 4, France.,Université Paul Sabatier, Toulouse, France
| | - Camille Villedieu
- CarMeN Laboratory, Inserm U1060, Univ-Lyon, Université Claude Bernard Lyon 1, Bron, France
| | - Helene Thibault
- CarMeN Laboratory, Inserm U1060, Univ-Lyon, Université Claude Bernard Lyon 1, Bron, France
| | - Delphine Baetz
- CarMeN Laboratory, Inserm U1060, Univ-Lyon, Université Claude Bernard Lyon 1, Bron, France
| | - Bernard Payrastre
- INSERM U1048 I2MC, Toulouse, Cedex 4, France.,Université Paul Sabatier, Toulouse, France
| | - Philippe Valet
- INSERM U1048 I2MC, Toulouse, Cedex 4, France.,Université Paul Sabatier, Toulouse, France
| | - Angelo Parini
- INSERM U1048 I2MC, Toulouse, Cedex 4, France.,Université Paul Sabatier, Toulouse, France
| | - Oksana Kunduzova
- INSERM U1048 I2MC, Toulouse, Cedex 4, France.,Université Paul Sabatier, Toulouse, France
| | - Frederic Boal
- INSERM U1048 I2MC, Toulouse, Cedex 4, France .,Université Paul Sabatier, Toulouse, France
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16
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Gopi M, Vanisree AJ. Attenuated levels of phospholipids in the striatum of rats infused with rotenone causing hemiparkinsonism as detected by simple dye-lipid complex. IBRO Rep 2017; 3:1-8. [PMID: 30135937 PMCID: PMC6084873 DOI: 10.1016/j.ibror.2017.06.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2016] [Revised: 04/24/2017] [Accepted: 06/10/2017] [Indexed: 12/15/2022] Open
Abstract
Parkinson's disease (PD), a progressive neurodegeneration, is characterized by loss of dopaminergic neurons in the substantia nigra (SN) and loss of motor co-ordination. Impaired metabolism of major lipids such as phospholipids which play regulatory roles in cellular functions and signaling has been implicated in the pathology of PD. We aim to investigate the striatal phospholipids (PLs) in hemiparkinsonism infused by rotenone in rats. As there are no cost-effective modes of PL, we have utilized dye-lipid complex technique for the first time in PD models for screening and also for semi-quantifying (individually) the levels of the deregulated PL in brain samples. Rats were divided into 2 groups: i. control and ii. ROT-infused which received intracranial injection of Rotenone (6 μg/μl; flow rate 0.2 μl/min). At the end of experimental period of 14 days, the striatum was dissected out for the analyses of PLs. Dye-based detection of PL and two-dimensional thin-layer chromatographic analyses of PL were performed. Detection of dye-PL complex was possible for phosphatidyl choline (PC), phosphatidyl inositol (PI), and spingomyelin (SM) (but not for phosphatidyl ethanolamine-PE) using dyes viz victoria blue B, toluidine blue and ammonium ferrothiocyanate, respectively. Two-dimensional analyses of phospholipids confirmed the dye-PL complex and depicted significant reduction (p < 0.05) on semi-quantitative assessment, in the striatum of control and hemiparkinsonic rats. We suggest a low level of PLs esp of PI in striatum of rats using a simple dye-detection that was validated by HR-LCMS. The finding implies that a critical role is being played by these PLs (PC, PI and SM) mainly PI (p < 0.001), in rotenone infused hemiparkinsonism, thus deserving wider but simpler investigations to detect and identify their role in parkinsonism.
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Key Words
- AD, Alzheimer's disease
- AFTC, Ammonium ferrothiocyanate
- ANSA, 1 Amino-2 naphthol-4 sulfonic acid
- DA, Dopaminergic neuron
- DMSO, Dimethyl sulfoxide
- Dye-lipid complex
- ESI, Electrospray ionization
- HCl, Hydrochloric acid
- HRLCMS, High resolution liquid chromatography–mass spectrometry
- MRM, Multiple reaction monitor
- MS, Mass spectrometry
- NM, Neuromelanin
- Na.EDTA, Sodium Ethylenediaminetetraacetic acid
- NaCl, Sodium chloride
- PC, Phosphatidyl choline
- PD, Parkinson's disease
- PE, Phosphatidyl ethanolamine
- PI(3,5)P2, Phosphatidylinositol 3,5-bisphosphate
- PI, Phosphoinositide
- PLs, Phospholipids
- Parkinson's disease
- Phospholipids
- PtdIns(3,4,5)P3, Phosphatidylinositol 3,4,5-trisphosphate
- PtdIns(4,5)P2, Phosphatidylinositol 4,5-bisphosphate
- PtdIns5P, Phosphatidylinositol 5-phosphate
- ROT, Rotenone
- Rotenone
- SM, Spingomyelin
- SNpc, Substantia nigra pars compacta
- Striatum
- TB, Toluidine blue dye
- TBAHS, tetrabutyl ammonium hydrogen sulphate
- TEM, Transmission electron microscopy
- TLC, Thin layer chromatography
- VBB, Victoria blue-B dye
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17
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Qiu S, Leung A, Bo Y, Kozak RA, Anand SP, Warkentin C, Salambanga FDR, Cui J, Kobinger G, Kobasa D, Côté M. Ebola virus requires phosphatidylinositol (3,5) bisphosphate production for efficient viral entry. Virology 2017; 513:17-28. [PMID: 29031163 DOI: 10.1016/j.virol.2017.09.028] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Revised: 09/28/2017] [Accepted: 09/30/2017] [Indexed: 12/11/2022]
Abstract
For entry, Ebola virus (EBOV) requires the interaction of its viral glycoprotein with the cellular protein Niemann-Pick C1 (NPC1) which resides in late endosomes and lysosomes. How EBOV is trafficked and delivered to NPC1 and whether this is positively regulated during entry remain unclear. Here, we show that the PIKfyve-ArPIKfyve-Sac3 cellular complex, which is involved in the metabolism of phosphatidylinositol (3,5) bisphosphate (PtdIns(3,5)P2), is critical for EBOV infection. Although the expression of all subunits of the complex was required for efficient entry, PIKfyve kinase activity was specifically critical for entry by all pathogenic filoviruses. Inhibition of PIKfyve prevented colocalization of EBOV with NPC1 and led to virus accumulation in intracellular vesicles with characteristics of early endosomes. Importantly, genetically-encoded phosphoinositide probes revealed an increase in PtdIns(3,5)P2-positive vesicles in cells during EBOV entry. Taken together, our studies suggest that EBOV requires PtdIns(3,5)P2 production in cells to promote efficient delivery to NPC1.
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Affiliation(s)
- Shirley Qiu
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Canada; Ottawa Institute of Systems Biology, University of Ottawa, Ottawa, Canada
| | - Anders Leung
- Special Pathogens Program, National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Canada
| | - Yuxia Bo
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Canada; Ottawa Institute of Systems Biology, University of Ottawa, Ottawa, Canada
| | - Robert A Kozak
- Special Pathogens Program, National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Canada
| | - Sai Priya Anand
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Canada; Ottawa Institute of Systems Biology, University of Ottawa, Ottawa, Canada
| | - Corina Warkentin
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Canada; Ottawa Institute of Systems Biology, University of Ottawa, Ottawa, Canada
| | - Fabiola D R Salambanga
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Canada; Ottawa Institute of Systems Biology, University of Ottawa, Ottawa, Canada
| | - Jennifer Cui
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Canada; Ottawa Institute of Systems Biology, University of Ottawa, Ottawa, Canada
| | - Gary Kobinger
- Special Pathogens Program, National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Canada
| | - Darwyn Kobasa
- Special Pathogens Program, National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Canada; Department of Medical Microbiology, University of Manitoba, Winnipeg, Canada
| | - Marceline Côté
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Canada; Ottawa Institute of Systems Biology, University of Ottawa, Ottawa, Canada.
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18
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De Craene JO, Bertazzi DL, Bär S, Friant S. Phosphoinositides, Major Actors in Membrane Trafficking and Lipid Signaling Pathways. Int J Mol Sci 2017; 18:ijms18030634. [PMID: 28294977 PMCID: PMC5372647 DOI: 10.3390/ijms18030634] [Citation(s) in RCA: 136] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Revised: 03/02/2017] [Accepted: 03/06/2017] [Indexed: 11/30/2022] Open
Abstract
Phosphoinositides are lipids involved in the vesicular transport of proteins and lipids between the different compartments of eukaryotic cells. They act by recruiting and/or activating effector proteins and thus are involved in regulating various cellular functions, such as vesicular budding, membrane fusion and cytoskeleton dynamics. Although detected in small concentrations in membranes, their role is essential to cell function, since imbalance in their concentrations is a hallmark of many cancers. Their synthesis involves phosphorylating/dephosphorylating positions D3, D4 and/or D5 of their inositol ring by specific lipid kinases and phosphatases. This process is tightly regulated and specific to the different intracellular membranes. Most enzymes involved in phosphoinositide synthesis are conserved between yeast and human, and their loss of function leads to severe diseases (cancer, myopathy, neuropathy and ciliopathy).
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Affiliation(s)
- Johan-Owen De Craene
- Department of Molecular and Cellular Genetics, Université de Strasbourg, CNRS, GMGM UMR 7156, F-67000 Strasbourg, France.
| | - Dimitri L Bertazzi
- Department of Molecular and Cellular Genetics, Université de Strasbourg, CNRS, GMGM UMR 7156, F-67000 Strasbourg, France.
| | - Séverine Bär
- Department of Molecular and Cellular Genetics, Université de Strasbourg, CNRS, GMGM UMR 7156, F-67000 Strasbourg, France.
| | - Sylvie Friant
- Department of Molecular and Cellular Genetics, Université de Strasbourg, CNRS, GMGM UMR 7156, F-67000 Strasbourg, France.
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19
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Hasegawa J, Strunk BS, Weisman LS. PI5P and PI(3,5)P 2: Minor, but Essential Phosphoinositides. Cell Struct Funct 2017; 42:49-60. [PMID: 28302928 DOI: 10.1247/csf.17003] [Citation(s) in RCA: 95] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
In most eukaryotes, phosphoinositides (PIs) have crucial roles in multiple cellular functions. Although the cellular levels of phosphatidylinositol 5-phosphate (PI5P) and phosphatidylinositol 3,5-bisphosphate (PI(3,5)P2) are extremely low relative to some other PIs, emerging evidence demonstrates that both lipids are crucial for the endocytic pathway, intracellular signaling, and adaptation to stress. Mutations that causes defects in the biosynthesis of PI5P and PI(3,5)P2 are linked to human diseases including neurodegenerative disorders. Here, we review recent findings on cellular roles of PI5P and PI(3,5)P2, as well as the pathophysiological importance of these lipids.Key words: Phosphoinositides, Membrane trafficking, Endocytosis, Vacuoles/Lysosomes, Fab1/PIKfyve.
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20
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Nagpal A, Ndamukong I, Hassan A, Avramova Z, Baluška F. Subcellular localizations of Arabidopsis myotubularins MTM1 and MTM2 suggest possible functions in vesicular trafficking between ER and cis-Golgi. JOURNAL OF PLANT PHYSIOLOGY 2016; 200:45-52. [PMID: 27340857 DOI: 10.1016/j.jplph.2016.06.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Revised: 06/03/2016] [Accepted: 06/03/2016] [Indexed: 06/06/2023]
Abstract
The two Arabidopsis genes AtMTM1 and AtMTM2 encode highly similar phosphoinositide 3-phosphatases from the myotubularin family. Despite the high-level conservation of structure and biochemical activities, their physiological roles have significantly diverged. The nature of a membrane and the concentrations of their membrane-anchored substrates (PtdIns3P or PtdIns3,5P2) and/or products (PtdIns5P and PtdIns) are considered critical for determining the functional specificity of myotubularins. We have performed comprehensive analyses of the subcellular localization of AtMTM1 and AtMTM2 using a variety of specific constructs transiently expressed in Nicotiana benthamiana leaf epidermal cells under the control of 35S promoter. AtMTM1 co-localized preferentially with cis-Golgi membranes, while AtMTM2 associated predominantly with ER membranes. In a stark contrast with animal/human MTMs, neither AtMTM1 nor AtMTM2 co-localizes with early or late endosomes or with TGN/EE compartments, making them unlikely participants in the endosomal trafficking system. Localization of the AtMTM2 is sensitive to cold and osmotic stress challenges. In contrast to animal myotubularins, Arabidopsis myotubularins do not associate with endosomes. Our results suggest that Arabidopsis myotubularins play a role in the vesicular trafficking between ER exit sites and cis-Golgi elements. The significance of these results is discussed also in the context of stress biology and plant autophagy.
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Affiliation(s)
| | - Ivan Ndamukong
- School of Biological Sciences, UNL, Lincoln NE, 68588, United States
| | - Ammar Hassan
- IZMB, University of Bonn, Kirschalle 1, 53115 Bonn, Germany
| | - Zoya Avramova
- School of Biological Sciences, UNL, Lincoln NE, 68588, United States.
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21
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Boal F, Puhar A, Xuereb JM, Kunduzova O, Sansonetti PJ, Payrastre B, Tronchère H. PI5P Triggers ICAM-1 Degradation in Shigella Infected Cells, Thus Dampening Immune Cell Recruitment. Cell Rep 2016; 14:750-759. [PMID: 26776508 DOI: 10.1016/j.celrep.2015.12.079] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Revised: 10/19/2015] [Accepted: 12/16/2015] [Indexed: 12/13/2022] Open
Abstract
Shigella flexneri, the pathogen responsible for bacillary dysentery, has evolved multiple strategies to control the inflammatory response. Here, we show that Shigella subverts the subcellular trafficking of the intercellular adhesion molecule-1 (ICAM-1), a key molecule in immune cell recruitment, in a mechanism dependent on the injected bacterial enzyme IpgD and its product, the lipid mediator PI5P. Overexpression of IpgD, but not a phosphatase dead mutant, induced the internalization and the degradation of ICAM-1 in intestinal epithelial cells. Remarkably, addition of permeant PI5P reproduced IpgD effects and led to the inhibition of neutrophil recruitment. Finally, these results were confirmed in an in vivo model of Shigella infection where IpgD-dependent ICAM-1 internalization reduced neutrophil adhesion. In conclusion, we describe here an immune evasion mechanism used by the pathogen Shigella to divert the host cell trafficking machinery in order to reduce immune cell recruitment.
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Affiliation(s)
- Frédéric Boal
- INSERM U1048, I2MC and Université Paul Sabatier, 31432 Toulouse, France
| | - Andrea Puhar
- INSERM U1202, Unité de Pathogénie Microbienne Moléculaire, Institut Pasteur, 75724 Paris Cedex 15, France; The Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå Centre for Microbial Research (UCMR) and Department of Molecular Biology, Umeå University, 901 87 Umeå, Sweden
| | - Jean-Marie Xuereb
- INSERM U1048, I2MC and Université Paul Sabatier, 31432 Toulouse, France
| | - Oksana Kunduzova
- INSERM U1048, I2MC and Université Paul Sabatier, 31432 Toulouse, France
| | - Philippe J Sansonetti
- INSERM U1202, Unité de Pathogénie Microbienne Moléculaire, Institut Pasteur, 75724 Paris Cedex 15, France
| | - Bernard Payrastre
- INSERM U1048, I2MC and Université Paul Sabatier, 31432 Toulouse, France; CHU de Toulouse, Laboratoire d'Hématologie, 31059 Toulouse Cedex 03, France
| | - Hélène Tronchère
- INSERM U1048, I2MC and Université Paul Sabatier, 31432 Toulouse, France.
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22
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Resolution of structure of PIP5K1A reveals molecular mechanism for its regulation by dimerization and dishevelled. Nat Commun 2015; 6:8205. [PMID: 26365782 PMCID: PMC4570271 DOI: 10.1038/ncomms9205] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Accepted: 07/28/2015] [Indexed: 02/06/2023] Open
Abstract
Type I phosphatidylinositol phosphate kinase (PIP5K1) phosphorylates the head group of phosphatidylinositol 4-phosphate (PtdIns4P) to generate PtdIns4,5P2, which plays important roles in a wide range of cellular functions including Wnt signalling. However, the lack of its structural information has hindered the understanding of its regulation. Here we report the crystal structure of the catalytic domain of zebrafish PIP5K1A at 3.3 Å resolution. This molecule forms a side-to-side dimer. Mutagenesis study of PIP5K1A reveals two adjacent interfaces for the dimerization and interaction with the DIX domain of the Wnt signalling molecule dishevelled. Although these interfaces are located distally to the catalytic/substrate-binding site, binding to these interfaces either through dimerization or the interaction with DIX stimulates PIP5K1 catalytic activity. DIX binding additionally enhances PIP5K1 substrate binding. Thus, this study elucidates regulatory mechanisms for this lipid kinase and provides a paradigm for the understanding of PIP5K1 regulation by their interacting molecules. Type I phosphatidylinositol phosphate kinase is an important component of many cellular pathways, including Wnt signalling. Here the authors report the crystal structure of the zebrafish protein along with in vitro assays that help to elucidate the regulation and function of this kinase.
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23
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Messenger SW, Thomas DD, Cooley MM, Jones EK, Falkowski MA, August BK, Fernandez LA, Gorelick FS, Groblewski GE. Early to Late Endosome Trafficking Controls Secretion and Zymogen Activation in Rodent and Human Pancreatic Acinar Cells. Cell Mol Gastroenterol Hepatol 2015; 1:695-709. [PMID: 26618189 PMCID: PMC4657148 DOI: 10.1016/j.jcmgh.2015.08.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
BACKGROUND & AIMS Pancreatic acinar cells have an expanded apical endosomal system, the physiological and pathophysiological significance of which is still emerging. Phosphatidylinositol-3,5-bisphosphate (PI(3,5)P2) is an essential phospholipid generated by PIKfyve, which phosphorylates phosphatidylinositol-3-phosphate (PI(3)P). PI(3,5)P2 is necessary for maturation of early endosomes (EE) to late endosomes (LE). Inhibition of EE to LE trafficking enhances anterograde endosomal trafficking and secretion at the plasma membrane by default through a recycling endosome (RE) intermediate. We assessed the effects of modulating PIKfyve activity on apical trafficking and pancreatitis responses in pancreatic acinar cells. METHODS Inhibition of EE to LE trafficking was achieved using pharmacological inhibitors of PIKfyve, expression of dominant negative PIKfyve K1877E, or constitutively active Rab5-GTP Q79L. Anterograde endosomal trafficking was manipulated by expression of constitutively active and dominant negative Rab11a mutants. The effects of these agents on secretion, endolysosomal exocytosis of lysosome associated membrane protein (LAMP1), and trypsinogen activation in response to high-dose CCK-8, bile acids and cigarette toxin was determined. RESULTS PIKfyve inhibition increased basal and stimulated secretion. Adenoviral overexpression of PIKfyve decreased secretion leading to cellular death. Expression of Rab5-GTP Q79L or Rab11a-GTP Q70L enhanced secretion. Conversely, dominant-negative Rab11a-GDP S25N reduced secretion. High-dose CCK inhibited endolysosomal exocytosis that was reversed by PIKfyve inhibition. PIKfyve inhibition blocked intracellular trypsin accumulation and cellular damage responses to high CCK-8, tobacco toxin, and bile salts in both rodent and human acini. CONCLUSIONS These data demonstrate that EE-LE trafficking acutely controls acinar secretion and the intracellular activation of zymogens leading to the pathogenicity of acute pancreatitis.
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Affiliation(s)
- Scott W. Messenger
- Department of Nutritional Sciences, University of Wisconsin, Madison, Wisconsin
| | - Diana D.H. Thomas
- Department of Nutritional Sciences, University of Wisconsin, Madison, Wisconsin
| | - Michelle M. Cooley
- Department of Nutritional Sciences, University of Wisconsin, Madison, Wisconsin
| | - Elaina K. Jones
- Department of Nutritional Sciences, University of Wisconsin, Madison, Wisconsin
| | | | - Benjamin K. August
- Department of Nutritional Sciences, University of Wisconsin, Madison, Wisconsin
| | | | - Fred S. Gorelick
- Department of Internal Medicine, School of Medicine, Yale University, New Haven, Connecticut,Department of Cell Biology, School of Medicine, Yale University, New Haven, Connecticut,Veterans Administration Connecticut Healthcare, West Haven, Connecticut
| | - Guy E. Groblewski
- Department of Nutritional Sciences, University of Wisconsin, Madison, Wisconsin,Correspondence Address correspondence to: Guy E. Groblewski, PhD, University of Wisconsin–Madison, Department of Nutritional Sciences, 1415 Linden Drive, Madison, Wisconsin 53706. fax: (608) 262-5860.University of Wisconsin–MadisonDepartment of Nutritional Sciences1415 Linden DriveMadisonWisconsin 53706
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24
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Bertazzi DL, De Craene JO, Bär S, Sanjuan-Vazquez M, Raess MA, Friant S. [Phosphoinositides: lipidic essential actors in the intracellular traffic]. Biol Aujourdhui 2015; 209:97-109. [PMID: 26115715 DOI: 10.1051/jbio/2015006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Indexed: 06/04/2023]
Abstract
Phosphoinositides (PPIn) are lipids involved in the vesicular transport of proteins between the different intracellular compartments. They act by recruiting and/or activating effector proteins and are thus involved in crucial cellular functions including vesicle budding, fusion and dynamics of membranes and regulation of the cytoskeleton. Although they are present in low concentrations in membranes, their activity is essential for cell survival and needs to be tightly controlled. Therefore, phosphatases and kinases specific of the various cellular membranes can phosphorylate/dephosphorylate their inositol ring on the positions D3, D4 and/or D5. The differential phosphorylation determines the intracellular localisation and the activity of the PPIn. Indeed, non-phosphorylated phosphatidylinositol (PtdIns) is the basic component of the PPIn and can be found in all eukaryotic cells at the cytoplasmic face of the ER, the Golgi, mitochondria and microsomes. It can get phosphorylated on position D4 to obtain PtdIns4P, a PPIn enriched in the Golgi compartment and involved in the maintenance of this organelle as well as anterograde and retrograde transport to and from the Golgi. PtdIns phosphorylation on position D3 results in PtdIns3P that is required for endosomal transport and multivesicular body (MVB) formation and sorting. These monophosphorylated PtdIns can be further phosphorylated to produce bisphophorylated PtdIns. Thus, PtdIns(4,5)P2, mainly produced by PtdIns4P phosphorylation, is enriched in the plasma membrane and involved in the regulation of actin cytoskeleton and endocytosis. PtdIns(3,5)P2, mainly produced by PtdIns3P phosphorylation, is enriched in late endosomes, MVBs and the lysosome/vacuole and plays a role in endosome to vacuole transport. PtdIns(3,4)P2 is absent in yeast, cells and mainly produced by PtdIns4P phosphorylation in human cells; PtdIns(3,4)P2 is localised in the plasma membrane and plays an important role as a second messenger by recruiting specific protein kinases (Akt and PDK1). Finally the triple phosphorylated PPIn, PtdIns(3,4,5)P3 also absent in yeast, is produced by the phosphorylation of PtdIns(3,4)P2 and localized at the plasma membrane of human cells where it binds proteins via their PH domain. Interaction partners include members of the Arf (ADP-ribosylation factors) family, PDK1 (Phosphoinositide Dependent Kinase 1) and Akt. Therefore this last PPIn is essential for the control of cell proliferation and its deregulation leads to the development of numerous cancers. In conclusion, the regulation of PPIn phosphorylation/dephosphorylation is complex and needs to be very precisely regulated. Indeed phosphatases and kinases allow the maintenance of the equilibrium between the different forms. PPIn play a crucial role in numerous cellular functions and a loss in their synthesis or regulation results in severe genetic diseases.
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Shisheva A, Sbrissa D, Ikonomov O. Plentiful PtdIns5P from scanty PtdIns(3,5)P2 or from ample PtdIns? PIKfyve-dependent models: Evidence and speculation (response to: DOI 10.1002/bies.201300012). Bioessays 2014; 37:267-77. [PMID: 25404370 DOI: 10.1002/bies.201400129] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Recently, we have presented data supporting the notion that PIKfyve not only produces the majority of constitutive phosphatidylinositol 5-phosphate (PtdIns5P) in mammalian cells but that it does so through direct synthesis from PtdIns. Another group, albeit obtaining similar data, suggests an alternative pathway whereby the low-abundance PtdIns(3,5)P2 undergoes hydrolysis by unidentified 3-phosphatases, thereby serving as a precursor for most of PtdIns5P. Here, we review the experimental evidence supporting constitutive synthesis of PtdIns5P from PtdIns by PIKfyve. We further emphasize that the experiments presented in support of the alternative pathway are also compatible with a direct mechanism for PIKfyve-catalyzed synthesis of PtdIns5P. While agreeing with the authors that constitutive PtdIns5P could theoretically be produced from PtdIns(3,5)P2 by 3-dephosphorylation, we argue that until direct evidence for such an alternative pathway is obtained, we should adhere to the existing experimental evidence and quantitative considerations, which favor direct PIKfyve-catalyzed synthesis for most constitutive PtdIns5P.
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Affiliation(s)
- Assia Shisheva
- Department of Physiology, Wayne State University School of Medicine, Detroit, MI, USA
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26
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Fant X, Durieu E, Chicanne G, Payrastre B, Sbrissa D, Shisheva A, Limanton E, Carreaux F, Bazureau JP, Meijer L. cdc-like/dual-specificity tyrosine phosphorylation-regulated kinases inhibitor leucettine L41 induces mTOR-dependent autophagy: implication for Alzheimer's disease. Mol Pharmacol 2014; 85:441-50. [PMID: 24366666 PMCID: PMC6067634 DOI: 10.1124/mol.113.090837] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2013] [Accepted: 12/23/2013] [Indexed: 12/26/2022] Open
Abstract
Leucettines, a family of pharmacological inhibitors of dual-specificity tyrosine phosphorylation regulated kinases and cdc-like kinases (CLKs), are currently under investigation for their potential therapeutic application to Down syndrome and Alzheimer's disease. We here report that leucettine L41 triggers bona fide autophagy in osteosarcoma U-2 OS cells and immortalized mouse hippocampal HT22 cells, characterized by microtubule-associated protein light chain 3 membrane translocation and foci formation. Leucettine L41-triggered autophagy requires the Unc-51-like kinase and is sensitive to the phosphatidylinositol 3-kinase (PI3K) inhibitors wortmannin and 3-methyladenine, suggesting that it acts through the mammalian target of rapamycin (mTOR)/PI3K-dependent pathway. Leucettine L41 does not act by modifying the autophagic flux of vesicles. Leucettine L41-induced autophagy correlates best with inhibition of CLKs. Leucettine L41 modestly inhibited phosphatidylinositol-3-phosphate 5-kinase, FYVE domain-containing activity as tested both in vitro and in vivo, which may also contribute to autophagy induction. Altogether these results demonstrate that leucettines can activate the autophagic mTOR/PI3K pathway, a characteristic that may turn advantageous in the context of Alzheimer's disease treatment.
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Affiliation(s)
- Xavier Fant
- Centre National de la Recherche Scientifique (CNRS), USR3151, "Protein Phosphorylation and Human Disease," Station Biologique, Roscoff cedex, France (X.F., E.D.); Institut National de la Santé et de la Recherche Médicale/Université Paul Sabatier Unité Mixte de Recherche (UMR) 1048, "Production et fonctions plaquettaires: signalisation et phosphoinositides" group, Institut des Maladies Métaboliques et Cardiovasculaires (I2MC), Toulouse cedex, France (G.C., B.P.); Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan (D.S., A.S.); Laboratoire Sciences Chimiques de Rennes, UMR CNRS 6226, Groupe Ingénierie Chimique et Molécules pour le Vivant (ICMV), Université de Rennes, Campus de Beaulieu, Rennes cedex, France (E.L., F.C., J.-P.B.); and ManRos Therapeutics, Perharidy Research Center, Roscoff, Bretagne, France (L.M.)
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Viaud J, Boal F, Tronchère H, Gaits-Iacovoni F, Payrastre B. Phosphatidylinositol 5-phosphate: A nuclear stress lipid and a tuner of membranes and cytoskeleton dynamics. Bioessays 2013; 36:260-72. [DOI: 10.1002/bies.201300132] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Julien Viaud
- Inserm U1048; I2MC and Université Paul Sabatier; Toulouse France
| | - Frédéric Boal
- Inserm U1048; I2MC and Université Paul Sabatier; Toulouse France
| | - Hélène Tronchère
- Inserm U1048; I2MC and Université Paul Sabatier; Toulouse France
| | | | - Bernard Payrastre
- Inserm U1048; I2MC and Université Paul Sabatier; Toulouse France
- CHU de Toulouse; Laboratoire d'Hématologie; Toulouse France
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28
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Abstract
Intracellular organelles, including endosomes, show differences not only in protein but also in lipid composition. It is becoming clear from the work of many laboratories that the mechanisms necessary to achieve such lipid segregation can operate at very different levels, including the membrane biophysical properties, the interactions with other lipids and proteins, and the turnover rates or distribution of metabolic enzymes. In turn, lipids can directly influence the organelle membrane properties by changing biophysical parameters and by recruiting partner effector proteins involved in protein sorting and membrane dynamics. In this review, we will discuss how lipids are sorted in endosomal membranes and how they impact on endosome functions.
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Affiliation(s)
- Christin Bissig
- Biochemistry Department, University of Geneva, 1211 Geneva 4, Switzerland
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Kawasaki T, Takemura N, Standley DM, Akira S, Kawai T. The second messenger phosphatidylinositol-5-phosphate facilitates antiviral innate immune signaling. Cell Host Microbe 2013; 14:148-58. [PMID: 23954154 DOI: 10.1016/j.chom.2013.07.011] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2013] [Revised: 05/17/2013] [Accepted: 07/16/2013] [Indexed: 02/08/2023]
Abstract
Innate immune receptors, notably Toll-like receptors (TLRs) and RIG-I-like receptors (RLRs), sense viral infection and activate transcription factors, including interferon regulatory factor-3 (IRF3), to induce type I interferon (IFN). We demonstrate that the lipid phosphatidylinositol-5-phosphate (PtdIns5P) is increased upon viral infection and facilitates type I IFN production by binding to IRF3 and its upstream kinase TBK1 and promoting TBK1-mediated IRF3 phosphorylation and activation. Additionally, we determine that PtdIns5P is produced through the kinase PIKfyve, which phosphorylates PtdIns to generate PtdIns5P. Accordingly, PIKfyve knockdown or pharamoclogical inhibition decreases PtdIns5P levels and type I IFN production after TLR or RLR stimulation, and results in increased viral replication. A synthetic PtdIns5P, C8-PtdIns5P, promotes IRF3 phosphorylation and cytokine production in dendritic cells and acts as an adjuvant to boost immune responses in immunized mice. Thus, PtdIns5P produced during viral infection is a second messenger that targets the TBK1-IRF3 axis to elicit antiviral immunity.
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Affiliation(s)
- Takumi Kawasaki
- Laboratory of Molecular Immunobiology, Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0192, Japan
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Shisheva A. PtdIns5P: news and views of its appearance, disappearance and deeds. Arch Biochem Biophys 2013; 538:171-80. [PMID: 23916588 DOI: 10.1016/j.abb.2013.07.023] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2013] [Accepted: 07/22/2013] [Indexed: 12/24/2022]
Abstract
Accumulated evidence indicates that PtdIns5P, one of the seven phosphoinositides, found now to be constitutively present in yeast, plants and metazoa, serves as a signaling molecule to modulate pleiotropic cellular functions in both the nucleus and the cytoplasm. The enzymatic routes in biogenesis of basal PtdIns5P have remained incompletely understood. The role for candidate kinase PIKfyve that is principally involved in PtdIns(3,5)P2 production, has been questioned. In this review article we scrutinize the past obstacles that prevented the definitive implication of PIKfyve in PtdIns5P biosynthesis from PtdIns and focus on the recent pharmacological and genetic advancements that now make this conclusion well supported. We further summarize our current knowledge of the diverse stimuli modulating PtdIns5P levels, binding partners and regulated cellular process, with particular reference to the available mechanistic insights for the relevant signaling pathways.
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Affiliation(s)
- Assia Shisheva
- Department of Physiology, Wayne State University School of Medicine, 540 E. Canfield, Detroit, MI 48201, United States.
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Ikonomov OC, Sbrissa D, Delvecchio K, Feng HZ, Cartee GD, Jin JP, Shisheva A. Muscle-specific Pikfyve gene disruption causes glucose intolerance, insulin resistance, adiposity, and hyperinsulinemia but not muscle fiber-type switching. Am J Physiol Endocrinol Metab 2013; 305:E119-31. [PMID: 23673157 PMCID: PMC3725567 DOI: 10.1152/ajpendo.00030.2013] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The evolutionarily conserved kinase PIKfyve that synthesizes PtdIns5P and PtdIns(3,5)P₂ has been implicated in insulin-regulated GLUT4 translocation/glucose entry in 3T3-L1 adipocytes. To decipher PIKfyve's role in muscle and systemic glucose metabolism, here we have developed a novel mouse model with Pikfyve gene disruption in striated muscle (MPIfKO). These mice exhibited systemic glucose intolerance and insulin resistance at an early age but had unaltered muscle mass or proportion of slow/fast-twitch muscle fibers. Insulin stimulation of in vivo or ex vivo glucose uptake and GLUT4 surface translocation was severely blunted in skeletal muscle. These changes were associated with premature attenuation of Akt phosphorylation in response to in vivo insulin, as tested in young mice. Starting at 10-11 wk of age, MPIfKO mice progressively accumulated greater body weight and fat mass. Despite increased adiposity, serum free fatty acid and triglyceride levels were normal until adulthood. Together with the undetectable lipid accumulation in liver, these data suggest that lipotoxicity and muscle fiber switching do not contribute to muscle insulin resistance in MPIfKO mice. Furthermore, the 80% increase in total fat mass resulted from increased fat cell size rather than altered fat cell number. The observed profound hyperinsulinemia combined with the documented increases in constitutive Akt activation, in vivo glucose uptake, and gene expression of key enzymes for fatty acid biosynthesis in MPIfKO fat tissue suggest that the latter is being sensitized for de novo lipid anabolism. Our data provide the first in vivo evidence that PIKfyve is essential for systemic glucose homeostasis and insulin-regulated glucose uptake/GLUT4 translocation in skeletal muscle.
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Affiliation(s)
- Ognian C Ikonomov
- Department of Physiology, Wayne State University School of Medicine, Detroit, MI 48201, USA
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32
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Nunès JA, Guittard G. An Emerging Role for PI5P in T Cell Biology. Front Immunol 2013; 4:80. [PMID: 23565114 PMCID: PMC3613722 DOI: 10.3389/fimmu.2013.00080] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2013] [Accepted: 03/15/2013] [Indexed: 11/30/2022] Open
Abstract
Phosphoinositides are critical regulators in cell biology. Phosphatidylinositol 4,5-bisphosphate, also known as PI(4,5)P2 or PIP2, was the first variety of phosphoinositide to enter in the T cell signaling scene. Phosphatidylinositol bis-phosphates are the substrates for different types of enzymes such as phospholipases C (β and γ isoforms) and phosphoinositide 3-kinases (PI3K class IA and IB) that are largely involved in signal transduction. However until recently, only a few studies highlighted phosphatidylinositol monophosphates as signaling molecules. This was mostly due to the difficulty of detection of some of these phosphoinositides, such as phosphatidylinositol 5-phosphate, also known as PI5P. Some compelling evidence argues for a role of PI5P in cell signaling and/or cell trafficking. Recently, we reported the detection of a PI5P increase upon TCR triggering. Here, we describe the current knowledge of the role of PI5P in T cell signaling. The future challenges that will be important to achieve in order to fully characterize the role of PI5P in T cell biology, will be discussed.
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Affiliation(s)
- Jacques A Nunès
- Immunology and Cancer, UMR7258, CNRS, Centre de Recherche en Cancerologie de Marseille Marseille, France ; Immunology and Cancer, U1068, INSERM, Centre de Recherche en Cancerologie de Marseille Marseille, France ; Immunology and Cancer, Institut Paoli-Calmettes Marseille, France ; Centre de Recherche en Cancerologie de Marseille, Aix-Marseille University Marseille, France
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Jones DR, Foulger R, Keune WJ, Bultsma Y, Divecha N. PtdIns5P is an oxidative stress-induced second messenger that regulates PKB activation. FASEB J 2012; 27:1644-56. [PMID: 23241309 DOI: 10.1096/fj.12-218842] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Oxidative stress initiates signaling pathways, which protect from stress-induced cellular damage, initiate apoptosis, or drive cells into senescence or into tumorigenesis. Oxidative stress regulates the activity of the cell survival factor PKB, through the regulation of PtdIns(3,4,5)P₃ synthesis. Whether oxidative stress regulates other phosphoinositides to control PKB activation is not clear. Here we show that PtdIns5P is a redox-regulated second messenger. In response to hydrogen peroxide (H₂O₂), we measured an increase in PtdIns5P in cells derived from human osteosarcoma, U2OS (5-fold); breast tumors, MDA-MB-468 (2-fold); and fibrosarcoma, HT1080 (3-fold); and in p53-null murine embryonic fibroblasts (8-fold). In U2OS cells, the increase in H₂O₂-dependent PtdIns5P did not require mTOR, PDK1, PKB, ERK, and p38 signaling or PIKfyve, a lipid kinase that increases PtdIns5P in response to osmotic and oncogenic signaling. A reduction in H₂O₂-induced PtdIns5P levels by the overexpression of PIP4K revealed its role in PKB activation. Suppression of H₂O₂-induced PtdIns5P generation reduced PKB activation and, surprisingly, reduced cell sensitivity to growth inhibition by H₂O₂. These data suggest that inhibition of PIP4K signaling might be useful as a novel strategy to increase the susceptibility of tumor cells to therapeutics that function through increased oxidative stress.
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Affiliation(s)
- David R Jones
- Cancer Research UK Inositide Laboratory, The Paterson Institute for Cancer Research, University of Manchester, Manchester, UK
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Bogatikov E, Munoz C, Pakladok T, Alesutan I, Shojaiefard M, Seebohm G, Föller M, Palmada M, Böhmer C, Bröer S, Lang F. Up-regulation of amino acid transporter SLC6A19 activity and surface protein abundance by PKB/Akt and PIKfyve. Cell Physiol Biochem 2012; 30:1538-46. [PMID: 23234856 DOI: 10.1159/000343341] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/04/2012] [Indexed: 01/03/2023] Open
Abstract
BACKGROUND The amino acid transporter B0AT1 (SLC6A19) accomplishes concentrative cellular uptake of neutral amino acids. SLC6A19 is stimulated by serum- & glucocorticoid-inducible kinase (SGK) isoforms. SGKs are related to PKB/Akt isoforms, which also stimulate several amino acid transporters. PKB/Akt modulates glucose transport in part by phosphorylating and thus activating phosphatidylinositol-3-phosphate-5-kinase (PIKfyve), which fosters carrier protein insertion into the cell membrane. The present study explored whether PKB/Akt and/or PIKfyve stimulate SLC6A19. METHODS SLC6A19 was expressed in Xenopus oocytes with or without wild-type PKB/Akt or inactive (T308A/S473A)PKB/Akt without or with additional expression of wild-type PIKfyve or PKB/Akt-resistant (S318A)PIKfyve. Electrogenic amino acid transport was determined by dual electrode voltage clamping. RESULTS In SLC6A19-expressing oocytes but not in water-injected oocytes, the addition of the neutral amino acid L-leucine (2 mM) to the bath generated a current (I(le)), which was significantly increased following coexpression of PKB/Akt, but not by coexpression of (T308A/S473A)PKB/Akt. The effect of PKB/Akt was augmented by additional coexpression of PIKfyve but not of (S318A)PIKfyve. Coexpression of PKB/Akt enhanced the maximal transport rate without significantly modifying the affinity of the carrier. The decline of I(le) following inhibition of carrier insertion by brefeldin A (5 µM) was similar in the absence and presence of PKB/Akt indicating that PKB/Akt stimulated carrier insertion into rather than inhibiting carrier retrieval from the cell membrane. CONCLUSION PKB/Akt up-regulates SLC6A19 activity, which may foster amino acid uptake into PKB/Akt-expressing epithelial and tumor cells.
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Affiliation(s)
- Evgenii Bogatikov
- Department of Physiology I, University of Tübingen, Tübingen, Germany
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Up-Regulation of the Inwardly Rectifying K+ Channel Kir2.1 (KCNJ2) by Protein Kinase B (PKB/Akt) and PIKfyve. J Membr Biol 2012. [DOI: 10.1007/s00232-012-9520-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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36
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Keune WJ, Jones DR, Bultsma Y, Sommer L, Zhou XZ, Lu KP, Divecha N. Regulation of phosphatidylinositol-5-phosphate signaling by Pin1 determines sensitivity to oxidative stress. Sci Signal 2012. [PMID: 23193159 DOI: 10.1126/scisignal.2003223] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Oxidative signaling and oxidative stress contribute to aging, cancer, and diseases resulting from neurodegeneration. Pin1 is a proline isomerase that recognizes phosphorylated substrates and regulates the localization and conformation of its targets. Pin1(-/-) mice show phenotypes associated with premature aging, yet mouse embryonic fibroblasts (MEFs) from these mice are resistant to hydrogen peroxide (H(2)O(2))-induced cell death. We found that the abundance of phosphatidylinositol-5-phosphate (PtdIns5P) was increased in response to H(2)O(2), an effect that was enhanced in Pin1(-/-) MEFs. Reduction of H(2)O(2)-induced PtdIns5P compromised cell viability in response to oxidative stress, suggesting that PtdIns5P contributed to the enhanced cell viability of Pin1(-/-) MEFs exposed to oxidative stress. The increased PtdIns5P in the Pin1(-/-) MEFs stimulated the expression of genes involved in defense against oxidative stress and reduced the accumulation of reactive oxygen species. Pin1 and PtdIns5P 4-kinases (PIP4Ks), enzymes that phosphorylate and thereby reduce the amount of PtdIns5P, interacted in a manner dependent on the phosphorylation of PIP4K. Although reintroduction of Pin1 into the Pin1(-/-) MEFs reduced the amount of PtdIns5P produced in response to H(2)O(2), in vitro assays indicated that the isomerase activity of Pin1 inhibited PIP4K activity. Whether this isomerise-mediated inhibition of PIP4K occurs in cells remains an open question, but the data suggest that the regulation of PIP4K by Pin1 may be complex.
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Affiliation(s)
- Willem-Jan Keune
- CRUK Inositide Laboratory, Paterson Institute for Cancer Research, The University of Manchester, Manchester M20 4BX, UK
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Oppelt A, Lobert VH, Haglund K, Mackey AM, Rameh LE, Liestøl K, Schink KO, Pedersen NM, Wenzel EM, Haugsten EM, Brech A, Rusten TE, Stenmark H, Wesche J. Production of phosphatidylinositol 5-phosphate via PIKfyve and MTMR3 regulates cell migration. EMBO Rep 2012; 14:57-64. [PMID: 23154468 DOI: 10.1038/embor.2012.183] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2012] [Revised: 10/24/2012] [Accepted: 10/26/2012] [Indexed: 12/12/2022] Open
Abstract
Although phosphatidylinositol 5-phosphate (PtdIns5P) is present in many cell types and its biogenesis is increased by diverse stimuli, its precise cellular function remains elusive. Here we show that PtdIns5P levels increase when cells are stimulated to move and we find PtdIns5P to promote cell migration in tissue culture and in a Drosophila in vivo model. First, class III phosphatidylinositol 3-kinase, which produces PtdIns3P, was shown to be involved in migration of fibroblasts. In a cell migration screen for proteins containing PtdIns3P-binding motifs, we identified the phosphoinositide 5-kinase PIKfyve and the phosphoinositide 3-phosphatase MTMR3, which together constitute a phosphoinositide loop that produces PtdIns5P via PtdIns(3,5)P(2). The ability of PtdIns5P to stimulate cell migration was demonstrated directly with exogenous PtdIns5P and a PtdIns5P-producing bacterial enzyme. Thus, the identified phosphoinositide loop defines a new role for PtdIns5P in cell migration.
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Affiliation(s)
- Angela Oppelt
- Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Oslo, Norway
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Ding Y, Ndamukong I, Zhao Y, Xia Y, Riethoven JJ, Jones DR, Divecha N, Avramova Z. Divergent functions of the myotubularin (MTM) homologs AtMTM1 and AtMTM2 in Arabidopsis thaliana: evolution of the plant MTM family. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2012; 70:866-878. [PMID: 22324391 DOI: 10.1111/j.1365-313x.2012.04936.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Myotubularin and myotubularin-related proteins are evolutionarily conserved in eukaryotes. Defects in their function result in muscular dystrophy, neuronal diseases and leukemia in humans. In contrast to the animal lineage, where genes encoding both active and inactive myotubularins (phosphoinositide 3-phosphatases) have appeared and proliferated in the basal metazoan group, myotubularin genes are not found in the unicellular relatives of green plants. However, they are present in land plants encoding proteins highly similar to the active metazoan enzymes. Despite their remarkable structural conservation, plant and animal myotubularins have significantly diverged in their functions. While loss of myotubularin function causes severe disease phenotypes in humans it is not essential for the cellular homeostasis under normal conditions in Arabidopsis thaliana. Instead, myotubularin deficiency is associated with altered tolerance to dehydration stress. The two Arabidopsis genes AtMTM1 and AtMTM2 have originated from a segmental chromosomal duplication and encode catalytically active enzymes. However, only AtMTM1 is involved in elevating the cellular level of phosphatidylinositol 5-phosphate in response to dehydration stress, and the two myotubularins differentially affect the Arabidopsis dehydration stress-responding transcriptome. AtMTM1 and AtMTM2 display different localization patterns in the cell, consistent with the idea that they associate with different membranes to perform specific functions. A single amino acid mutation in AtMTM2 (L250W) results in a dramatic loss of subcellular localization. Mutations in this region are linked to disease conditions in humans.
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MESH Headings
- Amino Acid Substitution
- Arabidopsis/genetics
- Arabidopsis/metabolism
- Arabidopsis Proteins/genetics
- Arabidopsis Proteins/metabolism
- Chromosome Duplication
- Chromosomes, Plant/genetics
- Chromosomes, Plant/metabolism
- Dehydration/metabolism
- Enzyme Activation
- Evolution, Molecular
- Gene Expression Regulation, Plant
- Genes, Plant
- Mitochondrial Proteins/genetics
- Mitochondrial Proteins/metabolism
- Oligonucleotide Array Sequence Analysis/methods
- Phosphatidylinositol Phosphates/metabolism
- Phosphoric Monoester Hydrolases/genetics
- Phosphoric Monoester Hydrolases/metabolism
- Plant Cells/metabolism
- Plants, Genetically Modified/genetics
- Plants, Genetically Modified/metabolism
- Protein Structure, Tertiary
- Protein Tyrosine Phosphatases, Non-Receptor/genetics
- Protein Tyrosine Phosphatases, Non-Receptor/metabolism
- Recombinant Fusion Proteins/genetics
- Recombinant Fusion Proteins/metabolism
- Soil
- Stress, Physiological
- Transcriptome
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Affiliation(s)
- Yong Ding
- School of Biological Sciences, University of Nebraska at Lincoln, Lincoln, NE 68588, USA
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Sbrissa D, Ikonomov OC, Filios C, Delvecchio K, Shisheva A. Functional dissociation between PIKfyve-synthesized PtdIns5P and PtdIns(3,5)P2 by means of the PIKfyve inhibitor YM201636. Am J Physiol Cell Physiol 2012; 303:C436-46. [PMID: 22621786 DOI: 10.1152/ajpcell.00105.2012] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
PIKfyve is an essential mammalian lipid kinase with pleiotropic cellular functions whose genetic knockout in mice leads to preimplantation lethality. Despite several reports for PIKfyve-catalyzed synthesis of phosphatidylinositol 5-phosphate (PtdIns5P) along with phosphatidylinositol-3,5-biphosphate [PtdIns(3,5)P(2)] in vitro and in vivo, the role of the PIKfyve pathway in intracellular PtdIns5P production remains underappreciated and the function of the PIKfyve-synthesized PtdIns5P pool poorly characterized. Hence, the recently discovered potent PIKfyve-selective inhibitor, the YM201636 compound, has been solely tested for inhibiting PtdIns(3,5)P(2) synthesis. Here, we have compared the in vitro and in vivo inhibitory potency of YM201636 toward PtdIns5P and PtdIns(3,5)P(2). Unexpectedly, we observed that at low doses (10-25 nM), YM201636 inhibited preferentially PtdIns5P rather than PtdIns(3,5)P(2) production in vitro, whereas at higher doses, the two products were similarly inhibited. In cellular contexts, YM201636 at 160 nM inhibited PtdIns5P synthesis twice more effectively compared with PtdIns(3,5)P(2) synthesis. In 3T3L1 adipocytes, human embryonic kidney 293 and Chinese hamster ovary (CHO-T) cells, levels of PtdIns5P dropped by 62-71% of the corresponding untreated controls, whereas those of PtdIns(3,5)P(2) fell by only 28-46%. The preferential inhibition of PtdIns5P versus PtdIns(3,5)P(2) at low doses of YM201636 was explored to probe contributions of the PIKfyve-catalyzed PtdIns5P pool to insulin-induced actin stress fiber disassembly in CHO-T cells, GLUT4 translocation in 3T3L1 adipocytes, and induction of aberrant cellular vacuolation in these or other cell types. The results provide the first experimental evidence that the principal pathway for PtdIns5P intracellular production is through PIKfyve and that insulin effect on actin stress fiber disassembly is mediated entirely by the PIKfyve-produced PtdIns5P pool.
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Affiliation(s)
- Diego Sbrissa
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan, USA
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The emerging role of PtdIns5P: another signalling phosphoinositide takes its place. Biochem Soc Trans 2012; 40:257-61. [PMID: 22260701 DOI: 10.1042/bst20110617] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Of the seven phosphoinositides, PtdIns5P remains the most enigmatic. However, recent research has begun to elucidate its physiological functions. It is now clear that PtdIns5P is found in several distinct subcellular locations, and the identification of a number of PtdIns5P-binding proteins points to its involvement in a variety of key processes, including signal transduction, membrane trafficking and regulation of gene expression. Although the mechanisms that control its turnover are not yet fully understood, the existence of multiple pathways for PtdIns5P regulation is consistent with this emerging versatility.
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Abstract
Phosphoinositides are important regulators of cellular homoeostasis and numerous signal-transduction pathways. One of their major features is their ability to recruit signalling proteins to membranes by direct interaction with phosphoinositide-binding modules. The distribution and dynamics of membrane phosphoinositides are therefore major determinants in the spatiotemporal control of cell signalling and membrane trafficking. However, standard biochemical approaches cannot reveal the dynamics of phosphoinositides at the single-cell level. A major technical advance has been the development of genetically encoded fluorescent phosphoinositide probes on the basis of the phosphoinositide-binding domains found in signalling proteins, such as the PH (pleckstrin homology) domain. This review describes the diverse fluorescent phosphoinositide probes available for imaging specific phosphoinositide species and how their use has improved the understanding of phosphoinositide signalling at the single-cell level.
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Affiliation(s)
- Guillaume Halet
- Department of Physiology, University College London, Gower Street, London WC1E 6BT, UK.
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Abstract
The level and turnover of phosphoinositides (PIs) are tightly controlled by a large set of PI-specific enzymes (PI kinases and phosphatases). Mammalian PI phosphatases are conserved through evolution and among this large family the dual-specificity phosphatase (PTP/DSP) are metal-independent enzymes displaying the amino acid signature Cys-X5-Arg-Thr/Ser (CX5RT/S) in their active site. Such catalytic site characterizes the myotubularin 3-phosphatases that dephosphorylate PtdIns3P and PtdIns(3,5)P₂ and produce PtdIns5P. Substrates of myotubularins have been implicated in endocytosis and membrane trafficking while PtdIns5P may have a role in signal transduction. As a paradox, 6 of the 14 members of the myotubularin family lack enzymatic activity and are considered as dead phosphatases. Several myotubularins have been genetically linked to human diseases: MTM1 is mutated in the congenital myopathy X-linked centronuclear or myotubular myopathy (XLCNM) and MTMR14 (JUMPY) has been linked to an autosomal form of such disease, while MTMR2 and MTMR13 are mutated in Charcot-Marie-Tooth (CMT) neuropathies. Furthermore, recent evidences from genetic association studies revealed that several other myotubularins could be associated to chronic disorders such as cancer and obesity, highlighting their importance for human health. Here, we discuss cellular and physiological roles of myotubularins and their implication in human diseases, and we present potential pathological mechanisms affecting specific tissues in myotubularin-associated diseases.
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Abstract
Phosphoinositides (PIs) are minor components of cellular membranes that play critical regulatory roles in several intracellular functions. This chapter describes the main enzymes regulating the turnover of each of the seven PIs in mammalian cells and introduces to some of their intracellular functions and to some evidences of their involvement in human diseases. Due to the complex interrelation between the distinct PIs and the plethora of functions that they can regulate inside a cell, this chapter is not meant to be a comprehensive coverage of all aspects of PI signalling but rather an introduction to this complex signalling field. For more details of their regulation/functions and extensive description of their intracellular roles, more detailed reviews are suggested on each single topic.
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Affiliation(s)
- Tania Maffucci
- Centre for Diabetes, Blizard Institute, Inositide Signalling Group, Queen Mary University of London, Barts and The London School of Medicine and Dentistry, UK.
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44
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Abstract
PIKfyve, a phosphoinositide 5-kinase synthesizing PtdIns(3,5)P₂ and PtdIns5P in a cellular context, belongs to an evolutionarily ancient gene family of PtdIns(3,5)P₂-synthesizing enzymes that, except for plants, are products of a single-copy gene across species. In the dozen years after its discovery, enormous progress has been made in characterizing the numerous PIKfyve cellular functions and the regulatory mechanisms that govern these functions. It became clear that PIKfyve does not act alone but, rather, it engages the scaffolding regulator ArPIKfyve and the phosphatase Sac3 to make a multiprotein "PAS" complex, so called for the first letters of the protein names. This complex relays antagonistic signals, one for synthesis, another for turnover of PtdIns(3,5)P₂, whose dysregulated coordination is linked to several human diseases. The physiological significance for each protein in the PAS complex is underscored by the early lethality of the mouse models with disruption in any of the three genes. This chapter summarizes our current knowledge of the diverse and complex functionality of PIKfyve and PtdIns(3,5)P₂/PtdIns5P products with particular highlights on recent discoveries of inherited or somatic mutations in PIKfyve and Sac3 linked to human disorders.
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Affiliation(s)
- Assia Shisheva
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan 48201, USA.
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Martelli AM, Ognibene A, Buontempo F, Fini M, Bressanin D, Goto K, McCubrey JA, Cocco L, Evangelisti C. Nuclear phosphoinositides and their roles in cell biology and disease. Crit Rev Biochem Mol Biol 2011; 46:436-57. [DOI: 10.3109/10409238.2011.609530] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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46
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Abstract
Being deeply connected to signalling, cell dynamics, growth, regulation, and defence, endocytic processes are linked to almost all aspects of cell life and disease. In this review, we focus on endosomes in the classical endocytic pathway, and on the programme of changes that lead to the formation and maturation of late endosomes/multivesicular bodies. The maturation programme entails a dramatic transformation of these dynamic organelles disconnecting them functionally and spatially from early endosomes and preparing them for their unidirectional role as a feeder pathway to lysosomes.
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Grainger DL, Tavelis C, Ryan AJ, Hinchliffe KA. Involvement of phosphatidylinositol 5-phosphate in insulin-stimulated glucose uptake in the L6 myotube model of skeletal muscle. Pflugers Arch 2011; 462:723-32. [PMID: 21847559 DOI: 10.1007/s00424-011-1008-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2011] [Revised: 07/28/2011] [Accepted: 08/01/2011] [Indexed: 11/25/2022]
Abstract
The phosphoinositide phospholipid PtdIns5P has previously been implicated in insulin-stimulated translocation of the glucose transporter GLUT4 into the plasma membrane of adipocytes, but its potential role in glucose transport in muscle has not been explored. The involvement of PtdIns5P in insulin-stimulated glucose uptake was therefore investigated in myotubes of the skeletal muscle cell line L6. Stimulation with insulin produced a transient increase in PtdIns5P, which was abolished by the over-expression of the highly active PtdIns5P 4-kinase PIP4Kα. PIP4Kα over-expression also abolished both the enhanced glucose uptake and the robust peak of PtdIns(3,4,5)P (3) production stimulated by insulin in myotubes. Delivery of exogenous PtdIns5P into unstimulated myotubes increased Akt phosphorylation, promoted GLUT4 relocalisation from internal membrane to plasma membrane fractions and its association with plasma membrane lawns and also stimulated glucose uptake in a tyrosine kinase and phosphoinositide 3-kinase (PI 3-kinase)-dependent fashion. Our results are consistent with a role for insulin-stimulated PtdIns5P production in regulating glucose transport by promoting PI 3-kinase signalling.
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Affiliation(s)
- Deborah L Grainger
- Faculty of Life Sciences, The University of Manchester, 2nd Floor Core Technology Facility, 46 Grafton Street, Manchester, M13 9NT, UK
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Dupuis-Coronas S, Lagarrigue F, Ramel D, Chicanne G, Saland E, Gaits-Iacovoni F, Payrastre B, Tronchère H. The nucleophosmin-anaplastic lymphoma kinase oncogene interacts, activates, and uses the kinase PIKfyve to increase invasiveness. J Biol Chem 2011; 286:32105-14. [PMID: 21737449 DOI: 10.1074/jbc.m111.227512] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
NPM-ALK is a chimeric tyrosine kinase detected in most anaplastic large cell lymphomas that results from the reciprocal translocation t(2,5)(p23;q35) that fuses the N-terminal domain of nucleophosmin (NPM) to the catalytic domain of the anaplastic lymphoma kinase (ALK) receptor. The constitutive activity of the kinase is responsible for its oncogenicity through the stimulation of several downstream signaling pathways, leading to cell proliferation, migration, and survival. We demonstrated previously that the high level of phosphatidylinositol 5-phosphate measured in NPM-ALK-expressing cells is controlled by the phosphoinositide kinase PIKfyve, a lipid kinase known for its role in vesicular trafficking. Here, we show that PIKfyve associates with NPM-ALK and that the interaction involves the 181-300 region of the oncogene. Moreover, we demonstrate that the tyrosine kinase activity of the oncogene controls PIKfyve lipid kinase activity but is dispensable for the formation of the complex. Silencing or inhibition of PIKfyve using siRNA or the PIKfyve inhibitor YM201636 have no effect on NPM-ALK-mediated proliferation and migration but strongly reduce invasive capacities of NPM-ALK-expressing cells and their capacity to degrade the extracellular matrix. Accordingly, immunofluorescence studies confirm a perturbation of matrix metalloproteinase 9 localization at the cell surface and defect in maturation. Altogether, these results suggest a role for PIKfyve in NPM-ALK-mediated invasion.
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Affiliation(s)
- Sophie Dupuis-Coronas
- INSERM, U1048, I2MC, Université Toulouse III Paul-Sabatier, Centre Hospitalier Universitaire de Toulouse, Toulouse Cedex 4, France
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Ding Y, Avramova Z, Fromm M. The Arabidopsis trithorax-like factor ATX1 functions in dehydration stress responses via ABA-dependent and ABA-independent pathways. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2011; 66:735-44. [PMID: 21309869 DOI: 10.1111/j.1365-313x.2011.04534.x] [Citation(s) in RCA: 127] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Emerging evidence suggests that the molecular mechanisms driving the responses of plants to environmental stresses are associated with specific chromatin modifications. Here, we demonstrate that the Arabidopsis trithorax-like factor ATX1, which trimethylates histone H3 at lysine 4 (H3K4me3), is involved in dehydration stress signaling in both abscisic acid (ABA)-dependent and ABA-independent pathways. The loss of function of ATX1 results in decreased germination rates, larger stomatal apertures, more rapid transpiration and decreased tolerance to dehydration stress in atx1 plants. This deficiency is caused in part by reduced ABA biosynthesis in atx1 plants resulting from decreased transcript levels from NCED3, which encodes a key enzyme controlling ABA production. Dehydration stress increased ATX1 binding to NCED3, and ATX1 was required for the increased levels of NCED3 transcripts and nucleosomal H3K4me3 that occurred during dehydration stress. Mechanistically, ATX1 affected the quantity of RNA polymerase II bound to NCED3. By upregulating NCED3 transcription and ABA production, ATX1 influenced ABA-regulated pathways and genes. ATX1 also affected the expression of ABA-independent genes, implicating ATX1 in diverse dehydration stress-response mechanisms in Arabidopsis.
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Affiliation(s)
- Yong Ding
- University of Nebraska Center for Biotechnology and Center for Plant Science Innovation, 1901 Vine Street, Lincoln, NE 68588, USA
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50
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Ikonomov OC, Sbrissa D, Delvecchio K, Xie Y, Jin JP, Rappolee D, Shisheva A. The phosphoinositide kinase PIKfyve is vital in early embryonic development: preimplantation lethality of PIKfyve-/- embryos but normality of PIKfyve+/- mice. J Biol Chem 2011; 286:13404-13. [PMID: 21349843 DOI: 10.1074/jbc.m111.222364] [Citation(s) in RCA: 109] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Gene mutations in the phosphoinositide-metabolizing enzymes are linked to various human diseases. In mammals, PIKfyve synthesizes PtdIns(3,5)P(2) and PtdIns5P lipids that regulate endosomal trafficking and responses to extracellular stimuli. The consequence of pikfyve gene ablation in mammals is unknown. To clarify the importance of PIKfyve and PIKfyve lipid products, in this study, we have characterized the first mouse model with global deletion of the pikfyve gene using the Cre-loxP approach. We report that nearly all PIKfyve(KO/KO) mutant embryos died before the 32-64-cell stage. Cultured fibroblasts derived from PIKfyve(flox/flox) embryos and rendered pikfyve-null by Cre recombinase expression displayed severely reduced DNA synthesis, consistent with impaired cell division causing early embryo lethality. The heterozygous PIKfyve(WT/KO) mice were born at the expected Mendelian ratio and developed into adulthood. PIKfyve(WT/KO) mice were ostensibly normal by several other in vivo, ex vivo, and in vitro criteria despite the fact that their levels of the PIKfyve protein and in vitro enzymatic activity in cells and tissues were 50-55% lower than those of wild-type mice. Consistently, steady-state levels of the PIKfyve products PtdIns(3,5)P(2) and PtdIns5P selectively decreased, but this reduction (35-40%) was 10-15% less than that expected based on PIKfyve protein reduction. The nonlinear decrease of the PIKfyve protein versus PIKfyve lipid products, the potential mechanism(s) discussed herein, may explain how one functional allele in PIKfyve(WT/KO) mice is able to support the demands for PtdIns(3,5)P(2)/PtdIns5P synthesis during life. Our data also shed light on the known human disorder linked to PIKFYVE mutations.
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Affiliation(s)
- Ognian C Ikonomov
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan 48201, USA
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