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Hammond GRV, Balla T. Polyphosphoinositide binding domains: Key to inositol lipid biology. Biochim Biophys Acta Mol Cell Biol Lipids 2015; 1851:746-58. [PMID: 25732852 DOI: 10.1016/j.bbalip.2015.02.013] [Citation(s) in RCA: 168] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Revised: 01/29/2015] [Accepted: 02/17/2015] [Indexed: 01/01/2023]
Abstract
Polyphosphoinositides (PPIn) are an important family of phospholipids located on the cytoplasmic leaflet of eukaryotic cell membranes. Collectively, they are critical for the regulation of many aspects of membrane homeostasis and signaling, with notable relevance to human physiology and disease. This regulation is achieved through the selective interaction of these lipids with hundreds of cellular proteins, and thus the capability to study these localized interactions is crucial to understanding their functions. In this review, we discuss current knowledge of the principle types of PPIn-protein interactions, focusing on specific lipid-binding domains. We then discuss how these domains have been re-tasked by biologists as molecular probes for these lipids in living cells. Finally, we describe how the knowledge gained with these probes, when combined with other techniques, has led to the current view of the lipids' localization and function in eukaryotes, focusing mainly on animal cells. This article is part of a Special Issue entitled Phosphoinositides.
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Affiliation(s)
- Gerald R V Hammond
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
| | - Tamas Balla
- Section on Molecular Signal Transduction, Eunice Shriver Kennedy National Institute for Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA.
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52
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Fiume R, Stijf-Bultsma Y, Shah ZH, Keune WJ, Jones DR, Jude JG, Divecha N. PIP4K and the role of nuclear phosphoinositides in tumour suppression. Biochim Biophys Acta Mol Cell Biol Lipids 2015; 1851:898-910. [PMID: 25728392 DOI: 10.1016/j.bbalip.2015.02.014] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2014] [Revised: 02/03/2015] [Accepted: 02/17/2015] [Indexed: 12/27/2022]
Abstract
Phosphatidylinositol-5-phosphate (PtdIns5P)-4-kinases (PIP4Ks) are stress-regulated lipid kinases that phosphorylate PtdIns5P to generate PtdIns(4,5)P₂. There are three isoforms of PIP4Ks: PIP4K2A, 2B and 2C, which localise to different subcellular compartments with the PIP4K2B isoform being localised predominantly in the nucleus. Suppression of PIP4K expression selectively prevents tumour cell growth in vitro and prevents tumour development in mice that have lost the tumour suppressor p53. p53 is lost or mutated in over 70% of all human tumours. These studies suggest that inhibition of PIP4K signalling constitutes a novel anti-cancer therapeutic target. In this review we will discuss the role of PIP4K in tumour suppression and speculate on how PIP4K modulates nuclear phosphoinositides (PPIns) and how this might impact on nuclear functions to regulate cell growth. This article is part of a Special Issue entitled Phosphoinositides.
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Affiliation(s)
- Roberta Fiume
- Cellular Signalling Laboratory, DIBINEM, University of Bologna, Bologna, Italy.
| | - Yvette Stijf-Bultsma
- Inositide Laboratory, Centre for Biological Sciences, Faculty of Natural & Environmental Sciences, Life Sciences Building 85, University of Southampton, Highfield Campus, Southampton SO17 1BJ, UK
| | - Zahid H Shah
- Inositide Laboratory, Centre for Biological Sciences, Faculty of Natural & Environmental Sciences, Life Sciences Building 85, University of Southampton, Highfield Campus, Southampton SO17 1BJ, UK
| | - Willem Jan Keune
- The Netherlands Cancer Institute, Amsterdam 1066CX, The Netherlands
| | - David R Jones
- Oncology iMED, AstraZeneca, Alderley Park, Macclesfield SK10 4TF, UK
| | - Julian Georg Jude
- IMP - Institute of Molecular Pathology, Vienna Biocenter, Dr. Bohr-Gasse 7, 1030 Vienna, Austria
| | - Nullin Divecha
- Inositide Laboratory, Centre for Biological Sciences, Faculty of Natural & Environmental Sciences, Life Sciences Building 85, University of Southampton, Highfield Campus, Southampton SO17 1BJ, UK.
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53
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Tan X, Sun Y, Thapa N, Liao Y, Hedman AC, Anderson RA. LAPTM4B is a PtdIns(4,5)P2 effector that regulates EGFR signaling, lysosomal sorting, and degradation. EMBO J 2015; 34:475-90. [PMID: 25588945 DOI: 10.15252/embj.201489425] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Lysosomal degradation is essential for the termination of EGF-stimulated EGF receptor (EGFR) signaling. This requires EGFR sorting to the intraluminal vesicles (ILVs) of multi-vesicular endosomes (MVEs). Cytosolic proteins including the ESCRT machineries are key regulators of EGFR intraluminal sorting, but roles for endosomal transmembrane proteins in receptor sorting are poorly defined. Here, we show that LAPTM4B, an endosomal transmembrane oncoprotein, inhibits EGF-induced EGFR intraluminal sorting and lysosomal degradation, leading to enhanced and prolonged EGFR signaling. LAPTM4B blocks EGFR sorting by promoting ubiquitination of Hrs (an ESCRT-0 subunit), which inhibits the Hrs association with ubiquitinated EGFR. This is counteracted by the endosomal PIP kinase, PIPKIγi5, which directly binds LAPTM4B and neutralizes the inhibitory function of LAPTM4B in EGFR sorting by generating PtdIns(4,5)P2 and recruiting SNX5. PtdIns(4,5)P2 and SNX5 function together to protect Hrs from ubiquitination, thereby promoting EGFR intraluminal sorting. These results reveal an essential layer of EGFR trafficking regulated by LAPTM4B, PtdIns(4,5)P2 signaling, and the ESCRT complex and define a mechanism by which the oncoprotein LAPTM4B can transform cells and promote tumor progression.
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Affiliation(s)
- Xiaojun Tan
- Program in Molecular and Cellular Pharmacology, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI, USA
| | - Yue Sun
- Program in Molecular and Cellular Pharmacology, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI, USA
| | - Narendra Thapa
- Program in Molecular and Cellular Pharmacology, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI, USA
| | - Yihan Liao
- Program in Molecular and Cellular Pharmacology, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI, USA
| | - Andrew C Hedman
- Program in Molecular and Cellular Pharmacology, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI, USA
| | - Richard A Anderson
- Program in Molecular and Cellular Pharmacology, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI, USA
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54
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Boal F, Mansour R, Gayral M, Saland E, Chicanne G, Xuereb JM, Marcellin M, Burlet-Schiltz O, Sansonetti PJ, Payrastre B, Tronchère H. TOM1 is a PI5P effector involved in the regulation of endosomal maturation. J Cell Sci 2015; 128:815-27. [DOI: 10.1242/jcs.166314] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Phosphoinositides represent a major class of lipids specifically involved in the organisation of signaling cascades, maintenance of the identity of organelles and regulation of multiple intracellular trafficking steps. We previously described that phosphatidylinositol 5-monophosphate (PI5P), produced by the Shigella flexneri phosphatase IpgD, is implicated in the endosomal sorting of the EGFR. Here, we show that the adaptor protein TOM1 is a new PI5P direct binding partner. We identify the domain of TOM1 involved in this interaction and characterize the binding motif. Finally, we demonstrate that the recruitment of TOM1 by PI5P on signaling endosomes is responsible for the delay in EGFR degradation and fluid-phase bulk endocytosis. Taken together, our data strongly suggest that PI5P-enrichment in signaling endosomes prevents endosomal maturation through the recruitment of TOM1, and point out to a new function of PI5P in regulating discrete maturation steps in the endosomal system.
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Bulley SJ, Clarke JH, Droubi A, Giudici ML, Irvine RF. Exploring phosphatidylinositol 5-phosphate 4-kinase function. Adv Biol Regul 2014; 57:193-202. [PMID: 25311266 PMCID: PMC4359101 DOI: 10.1016/j.jbior.2014.09.007] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Revised: 09/01/2014] [Accepted: 09/02/2014] [Indexed: 11/30/2022]
Abstract
The family of phosphatidylinositol 5-phosphate 4-kinases (PI5P4Ks) is emerging from a comparative backwater in inositide signalling into the mainstream, as is their substrate, phosphatidylinositol 5-phosphate (PI5P). Here we review some of the key questions about the PI5P4Ks, their localisation, interaction, and regulation and also we summarise our current understanding of how PI5P is synthesised and what its cellular functions might be. Finally, some of the evidence for the involvement of PI5P4Ks in pathology is discussed.
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Affiliation(s)
- Simon J Bulley
- Department of Pharmacology, Tennis Court Road, Cambridge, CB2 1PD, UK
| | - Jonathan H Clarke
- Department of Pharmacology, Tennis Court Road, Cambridge, CB2 1PD, UK
| | - Alaa Droubi
- Department of Pharmacology, Tennis Court Road, Cambridge, CB2 1PD, UK
| | | | - Robin F Irvine
- Department of Pharmacology, Tennis Court Road, Cambridge, CB2 1PD, UK.
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56
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Pizarro-Cerdá J, Kühbacher A, Cossart P. Phosphoinositides and host-pathogen interactions. Biochim Biophys Acta Mol Cell Biol Lipids 2014; 1851:911-8. [PMID: 25241942 DOI: 10.1016/j.bbalip.2014.09.011] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Revised: 09/09/2014] [Accepted: 09/10/2014] [Indexed: 01/08/2023]
Abstract
Phosphoinositides control key cellular processes including vesicular trafficking and actin polymerization. Intracellular bacterial pathogens manipulate phosphoinositide metabolism in order to promote their uptake by target cells and to direct in some cases the biogenesis of their replication compartments. In this chapter, we review the molecular strategies that major pathogens including Listeria, Mycobacterium, Shigella, Salmonella, Legionella and Yersinia use to hijack phosphoinositides during infection. This article is part of a Special Issue entitled Phosphoinositides.
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Affiliation(s)
- Javier Pizarro-Cerdá
- Institut Pasteur, Unité des Interactions Bactéries-Cellules, F-75015 Paris, France; INSERM, U604, F-75015 Paris, France; INRA, USC2020, F-75015 Paris, France
| | - Andreas Kühbacher
- Fraunhofer Institute for Interfacial Engineering and Biotechnology IGB, Department of Molecular Biotechnology, Stuttgart G-70569, Germany
| | - Pascale Cossart
- Institut Pasteur, Unité des Interactions Bactéries-Cellules, F-75015 Paris, France; INSERM, U604, F-75015 Paris, France; INRA, USC2020, F-75015 Paris, France
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57
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Abstract
The specific interaction of phosphoinositides with proteins is critical for a plethora of cellular processes, including cytoskeleton remodelling, mitogenic signalling, ion channel regulation and membrane traffic. The spatiotemporal restriction of different phosphoinositide species helps to define compartments within the cell, and this is particularly important for membrane trafficking within both the secretory and endocytic pathways. Phosphoinositide homoeostasis is tightly regulated by a large number of inositol kinases and phosphatases, which respectively phosphorylate and dephosphorylate distinct phosphoinositide species. Many of these enzymes have been implicated in regulating membrane trafficking and, accordingly, their dysregulation has been linked to a number of human diseases. In the present review, we focus on the inositol phosphatases, concentrating on their roles in membrane trafficking and the human diseases with which they have been associated.
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58
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Roxas JL, Ryan K, Vedantam G, Viswanathan VK. Enteropathogenic Escherichia coli dynamically regulates EGFR signaling in intestinal epithelial cells. Am J Physiol Gastrointest Liver Physiol 2014; 307:G374-80. [PMID: 24904077 PMCID: PMC4121633 DOI: 10.1152/ajpgi.00312.2013] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The diarrheagenic pathogen enteropathogenic Escherichia coli (EPEC) dynamically modulates the survival of infected host intestinal epithelial cells. In the initial stages of infection, several prosurvival signaling events are activated in host cells. These include the phosphorylation of epidermal growth factor receptor (EGFR) and the consequent activation of the phosphatidylinositol-3 kinase/Akt pathway. While studying this pathway in infected epithelial cells, we observed EGFR depletion at later stages of infection, followed subsequently by a decrease in phospho-EGFR. EGFR loss was not dependent on receptor phosphorylation, or on canonical proteasome- and lysosome-dependent processes. Although a type III secretion mutant (ΔescN) stimulated EGFR phosphorylation, it failed to induce receptor degradation. To identify the specific EPEC effector molecule(s) that influenced EGFR stability, epithelial cells infected with isogenic mutant EPEC strains were examined. An EPEC ΔespF strain failed to induce EGFR degradation, whereas EPEC ΔespZ accentuated receptor loss in infected cells. Given the known and contrasting effects of EspF and EspZ on caspase activation, and the known role of proteases in cleaving EGFR, we explored the effect of caspase inhibitors on infection-dependent EGFR loss. The pan-caspase inhibitor Q-VD-OPh blocked EPEC-induced EGFR cleavage in a dose-dependent manner. Taken together, our data suggest that EPEC EspF stimulates caspase-dependent EGFR cleavage and loss, whereas EspZ inhibits this process. Whereas EGFR phosphorylation contributes to the survival of host cells early in infection, EspF-driven caspase activation and consequent EGFR loss likely induce a precipitous increase in host cell death later in the infectious process.
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Affiliation(s)
- Jennifer Lising Roxas
- 1School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, Arizona;
| | - Katheryn Ryan
- 1School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, Arizona;
| | - Gayatri Vedantam
- 1School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, Arizona; ,2Department of Immunobiology, University of Arizona, Tucson, Arizona; and ,3The BIO5 Institute for Collaborative Research, University of Arizona, Tucson, Arizona
| | - V. K. Viswanathan
- 1School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, Arizona; ,2Department of Immunobiology, University of Arizona, Tucson, Arizona; and ,3The BIO5 Institute for Collaborative Research, University of Arizona, Tucson, Arizona
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59
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Phosphatidylinositol 5-phosphate regulates invasion through binding and activation of Tiam1. Nat Commun 2014; 5:4080. [PMID: 24905281 DOI: 10.1038/ncomms5080] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Accepted: 05/09/2014] [Indexed: 12/13/2022] Open
Abstract
PtdIns5P is a lipid messenger acting as a stress-response mediator in the nucleus, and known to maintain cell activation through traffic alterations upon bacterial infection. Here, we show that PtdIns5P regulates actin dynamics and invasion via recruitment and activation of the exchange factor Tiam1 and Rac1. Restricted Rac1 activation results from the binding of Tiam1 DH-PH domains to PtdIns5P. Using an assay that mimics Rac1 membrane anchoring by using Rac1-His and liposomes containing Ni(2+)-NTA modified lipids, we demonstrate that intrinsic Tiam1 DH-PH activity increases when Rac1 is anchored in a PtdIns5P-enriched environment. This pathway appears to be general since it is valid in different pathophysiological models: receptor tyrosine kinase activation, bacterial phosphatase IpgD expression and the invasive NPM-ALK(+) lymphomas. The discovery that PtdIns5P could be a keystone of GTPases and cytoskeleton spatiotemporal regulation opens important research avenues towards unravelling new strategies counteracting cell invasion.
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60
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Zheng K, Kitazato K, Wang Y. Viruses exploit the function of epidermal growth factor receptor. Rev Med Virol 2014; 24:274-86. [PMID: 24888553 DOI: 10.1002/rmv.1796] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2014] [Revised: 04/15/2014] [Accepted: 04/16/2014] [Indexed: 12/21/2022]
Abstract
Epidermal growth factor receptor (EGFR) is a receptor tyrosine kinase that regulates cellular homeostatic processes. Following ligand binding, EGFR activates different downstream signalling cascades that promote cell survival, proliferation, motility, and angiogenesis and induces F-actin-dependent EGFR endocytosis, which relocalises the activated receptors for degradation or recycling. The responses that are induced by ligand binding to EGFR, including cell signalling activation, protein kinase phosphorylation and cytoskeletal network rearrangement, resemble those induced by virus infection. Increasing evidence demonstrates that many viruses usurp EGFR endocytosis or EGFR-mediated signalling for entry, replication, inflammation, and viral antagonism to the host antiviral system. In addition, viruses have acquired sophisticated mechanisms to regulate EGFR functions by interrupting the EGFR-recycling process and modulating EGFR expression. In this review, we provide an overview of the mechanisms by which viruses alter EGFR signalling in favour of their continued survival.
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Affiliation(s)
- Kai Zheng
- Guangzhou Jinan Biomedicine Research and Development Center, National Engineering, Research Center of Genetic Medicine, Jinan University, Guangzhou, China; College of Life Science and Technology, Jinan University, Guangzhou, China
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61
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Puhar A, Tronchère H, Payrastre B, Nhieu GTV, Sansonetti PJ. A Shigella effector dampens inflammation by regulating epithelial release of danger signal ATP through production of the lipid mediator PtdIns5P. Immunity 2014; 39:1121-31. [PMID: 24332032 DOI: 10.1016/j.immuni.2013.11.013] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Accepted: 10/09/2013] [Indexed: 12/20/2022]
Abstract
Upon infection with Shigella flexneri, epithelial cells release ATP through connexin hemichannels. However, the pathophysiological consequence and the regulation of this process are unclear. Here we showed that in intestinal epithelial cell ATP release was an early alert response to infection with enteric pathogens that eventually promoted inflammation of the gut. Shigella evolved to escape this inflammatory reaction by its type III secretion effector IpgD, which blocked hemichannels via the production of the lipid PtdIns5P. Infection with an ipgD mutant resulted in rapid hemichannel-dependent accumulation of extracellular ATP in vitro and in vivo, which preceded the onset of inflammation. At later stages of infection, ipgD-deficient Shigella caused strong intestinal inflammation owing to extracellular ATP. We therefore describe a new paradigm of host-pathogen interaction based on endogenous danger signaling and identify extracellular ATP as key regulator of mucosal inflammation during infection. Our data provide new angles of attack for the development of anti-inflammatory molecules.
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Affiliation(s)
- Andrea Puhar
- Inserm U786, Unité de Pathogénie Microbienne Moléculaire, 75724 Paris Cedex 15, France; Institut Pasteur, Unité de Pathogénie Microbienne Moléculaire, 75724 Paris Cedex 15, France.
| | - Hélène Tronchère
- Inserm U1048, I2MC, 31432 Toulouse Cedex 4, France; Université Toulouse 3, I2MC, 31432 Toulouse Cedex 4, France
| | - Bernard Payrastre
- Inserm U1048, I2MC, 31432 Toulouse Cedex 4, France; Université Toulouse 3, I2MC, 31432 Toulouse Cedex 4, France; CHU Toulouse, Laboratoire d'Hématologie, 31432 Toulouse Cedex 4, France
| | - Guy Tran Van Nhieu
- Inserm U1050, Equipe Communication Intercellulaire et Infections Microbiennes, CIRB, 75231 Paris Cedex 5, France; CNRS UMR7241, Equipe Communication Intercellulaire et Infections Microbiennes, CIRB, 75231 Paris Cedex 5, France; Collège de France, Equipe Communication Intercellulaire et Infections Microbiennes, CIRB, 75231 Paris Cedex 5, France
| | - Philippe J Sansonetti
- Inserm U786, Unité de Pathogénie Microbienne Moléculaire, 75724 Paris Cedex 15, France; Institut Pasteur, Unité de Pathogénie Microbienne Moléculaire, 75724 Paris Cedex 15, France.
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62
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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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63
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Evolutionarily conserved structural changes in phosphatidylinositol 5-phosphate 4-kinase (PI5P4K) isoforms are responsible for differences in enzyme activity and localization. Biochem J 2013; 454:49-57. [PMID: 23758345 PMCID: PMC3749867 DOI: 10.1042/bj20130488] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Mammals have genes coding for three PI5P4Ks (PtdIns5P 4-kinases), and these have different cellular localizations, tissue distributions and lipid kinase activities. We describe in the present paper a detailed molecular exploration of human PI5P4Ks α, β and γ, as well as their fly and worm homologues, to understand how and why these differences came to be. The intrinsic ATPase activities of the three isoforms are very similar, and we show that differences in their G-loop regions can account for much of their wide differences in lipid kinase activity. We have also undertaken an extensive in silico evolutionary study of the PI5P4K family, and show experimentally that the single PI5P4K homologues from Caenorhabditis elegans and Drosophila melanogaster are as widely different in activity as the most divergent mammalian isoforms. Finally we show that the close association of PI5P4Ks α and γ is a true heterodimerization, and not a higher oligomer association of homodimers. We reveal that structural modelling is consistent with this and with the apparently random heterodimerization that we had earlier observed between PI5P4Kα and PI5P4Kβ [Wang, Bond, Letcher, Richardson, Lilley, Irvine and Clarke (2010), Biochem. J. 430, 215–221]. Overall the molecular diversity of mammalian PI5P4Ks explains much of their properties and behaviour, but their physiological functionality remains elusive.
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64
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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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65
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Schmutz C, Ahrné E, Kasper CA, Tschon T, Sorg I, Dreier RF, Schmidt A, Arrieumerlou C. Systems-level overview of host protein phosphorylation during Shigella flexneri infection revealed by phosphoproteomics. Mol Cell Proteomics 2013; 12:2952-68. [PMID: 23828894 PMCID: PMC3790303 DOI: 10.1074/mcp.m113.029918] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Revised: 06/14/2013] [Indexed: 01/01/2023] Open
Abstract
The enteroinvasive bacterium Shigella flexneri invades the intestinal epithelium of humans. During infection, several injected effector proteins promote bacterial internalization, and interfere with multiple host cell responses. To obtain a systems-level overview of host signaling during infection, we analyzed the global dynamics of protein phosphorylation by liquid chromatography-tandem MS and identified several hundred of proteins undergoing a phosphorylation change during the first hours of infection. Functional bioinformatic analysis revealed that they were mostly related to the cytoskeleton, transcription, signal transduction, and cell cycle. Fuzzy c-means clustering identified six temporal profiles of phosphorylation and a functional module composed of ATM-phosphorylated proteins related to genotoxic stress. Pathway enrichment analysis defined mTOR as the most overrepresented pathway. We showed that mTOR complex 1 and 2 were required for S6 kinase and AKT activation, respectively. Comparison with a published phosphoproteome of Salmonella typhimurium-infected cells revealed a large subset of coregulated phosphoproteins. Finally, we showed that S. flexneri effector OspF affected the phosphorylation of several hundred proteins, thereby demonstrating the wide-reaching impact of a single bacterial effector on the host signaling network.
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Affiliation(s)
- Christoph Schmutz
- From the ‡Biozentrum, University of Basel, Klingelbergstrasse 50/70, 4056 Basel, Switzerland
| | - Erik Ahrné
- From the ‡Biozentrum, University of Basel, Klingelbergstrasse 50/70, 4056 Basel, Switzerland
| | - Christoph A. Kasper
- From the ‡Biozentrum, University of Basel, Klingelbergstrasse 50/70, 4056 Basel, Switzerland
| | - Therese Tschon
- From the ‡Biozentrum, University of Basel, Klingelbergstrasse 50/70, 4056 Basel, Switzerland
| | - Isabel Sorg
- From the ‡Biozentrum, University of Basel, Klingelbergstrasse 50/70, 4056 Basel, Switzerland
| | - Roland F. Dreier
- From the ‡Biozentrum, University of Basel, Klingelbergstrasse 50/70, 4056 Basel, Switzerland
| | - Alexander Schmidt
- From the ‡Biozentrum, University of Basel, Klingelbergstrasse 50/70, 4056 Basel, Switzerland
| | - Cécile Arrieumerlou
- From the ‡Biozentrum, University of Basel, Klingelbergstrasse 50/70, 4056 Basel, Switzerland
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66
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Aizel K, Biou V, Navaza J, Duarte LV, Campanacci V, Cherfils J, Zeghouf M. Integrated conformational and lipid-sensing regulation of endosomal ArfGEF BRAG2. PLoS Biol 2013; 11:e1001652. [PMID: 24058294 PMCID: PMC3769224 DOI: 10.1371/journal.pbio.1001652] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2013] [Accepted: 07/31/2013] [Indexed: 11/24/2022] Open
Abstract
The structure of endosomal ArfGEF BRAG2 in complex with Arf1, combined with an analysis of this GEF's efficiency on membranes, reveals a regulatory mechanism that simultaneously optimizes membrane recruitment and nucleotide exchange. The mechanisms whereby guanine nucleotide exchange factors (GEFs) coordinate their subcellular targeting to their activation of small GTPases remain poorly understood. Here we analyzed how membranes control the efficiency of human BRAG2, an ArfGEF involved in receptor endocytosis, Wnt signaling, and tumor invasion. The crystal structure of an Arf1–BRAG2 complex that mimics a membrane-bound intermediate revealed an atypical PH domain that is constitutively anchored to the catalytic Sec7 domain and interacts with Arf. Combined with the quantitative analysis of BRAG2 exchange activity reconstituted on membranes, we find that this PH domain potentiates nucleotide exchange by about 2,000-fold by cumulative conformational and membrane-targeting contributions. Furthermore, it restricts BRAG2 activity to negatively charged membranes without phosphoinositide specificity, using a positively charged surface peripheral to but excluding the canonical lipid-binding pocket. This suggests a model of BRAG2 regulation along the early endosomal pathway that expands the repertoire of GEF regulatory mechanisms. Notably, it departs from the auto-inhibitory and feedback loop paradigm emerging from studies of SOS and cytohesins. It also uncovers a novel mechanism of unspecific lipid-sensing by PH domains that may allow sustained binding to maturating membranes. Understanding the molecular mechanisms that allow guanine exchange factor proteins (GEFs) to coordinate their GDP/GTP exchange activity with their being targeted to specific intracellular membranes is an important issue. In this study, we solved the crystal structure of the ArfGEF BRAG2, an endosomal protein that is involved in invasive phenotypes in various tumors, in a complex with the small GTPase Arf1. We show that the pleckstrin homology (PH) domain of BRAG2 atypically does not auto-inhibit its Sec7 domain (as has been seen in ArfGEFs belonging to the cytohesin family), but instead potentiates nucleotide exchange 10-fold in solution and up to 2,000-fold in the presence of liposomes. This stimulatory effect requires negatively charged membranes, and does not involve a preference of the PH domain for specific phosphoinositides or the use of its canonical lipid-binding pocket. This uncovers a regulatory mechanism in which the PH domain controls GEF efficiency by concurrently optimizing membrane recruitment and nucleotide exchange.
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Affiliation(s)
- Kaheina Aizel
- Laboratoire d'Enzymologie et Biochimie Structurales, CNRS, Gif-sur-Yvette, France
| | - Valérie Biou
- Laboratoire d'Enzymologie et Biochimie Structurales, CNRS, Gif-sur-Yvette, France
| | - Jorge Navaza
- Institut de Biologie Structurale, CNRS/CEA/Université Joseph Fourier, Grenoble, France
- Unidad de Biofísica CSIC-UPV/EHU, Leioa, Bizkaia, Spain
| | - Lionel V. Duarte
- Laboratoire d'Enzymologie et Biochimie Structurales, CNRS, Gif-sur-Yvette, France
| | - Valérie Campanacci
- Laboratoire d'Enzymologie et Biochimie Structurales, CNRS, Gif-sur-Yvette, France
| | - Jacqueline Cherfils
- Laboratoire d'Enzymologie et Biochimie Structurales, CNRS, Gif-sur-Yvette, France
- * E-mail: (JC); (MZ)
| | - Mahel Zeghouf
- Laboratoire d'Enzymologie et Biochimie Structurales, CNRS, Gif-sur-Yvette, France
- * E-mail: (JC); (MZ)
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67
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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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68
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Subversion of trafficking, apoptosis, and innate immunity by type III secretion system effectors. Trends Microbiol 2013; 21:430-41. [DOI: 10.1016/j.tim.2013.06.008] [Citation(s) in RCA: 100] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Revised: 05/08/2013] [Accepted: 06/18/2013] [Indexed: 11/17/2022]
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69
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Abstract
Phosphoinositides (PIs) make up only a small fraction of cellular phospholipids, yet they control almost all aspects of a cell's life and death. These lipids gained tremendous research interest as plasma membrane signaling molecules when discovered in the 1970s and 1980s. Research in the last 15 years has added a wide range of biological processes regulated by PIs, turning these lipids into one of the most universal signaling entities in eukaryotic cells. PIs control organelle biology by regulating vesicular trafficking, but they also modulate lipid distribution and metabolism via their close relationship with lipid transfer proteins. PIs regulate ion channels, pumps, and transporters and control both endocytic and exocytic processes. The nuclear phosphoinositides have grown from being an epiphenomenon to a research area of its own. As expected from such pleiotropic regulators, derangements of phosphoinositide metabolism are responsible for a number of human diseases ranging from rare genetic disorders to the most common ones such as cancer, obesity, and diabetes. Moreover, it is increasingly evident that a number of infectious agents hijack the PI regulatory systems of host cells for their intracellular movements, replication, and assembly. As a result, PI converting enzymes began to be noticed by pharmaceutical companies as potential therapeutic targets. This review is an attempt to give an overview of this enormous research field focusing on major developments in diverse areas of basic science linked to cellular physiology and disease.
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Affiliation(s)
- Tamas Balla
- Section on Molecular Signal Transduction, Program for Developmental Neuroscience, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA.
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70
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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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71
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Elouarrat D, van der Velden YU, Jones DR, Moolenaar WH, Divecha N, Haramis APG. Role of phosphatidylinositol 5-phosphate 4-kinase α in zebrafish development. Int J Biochem Cell Biol 2013; 45:1293-301. [PMID: 23542014 DOI: 10.1016/j.biocel.2013.03.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Revised: 03/12/2013] [Accepted: 03/13/2013] [Indexed: 10/27/2022]
Abstract
Phosphatidylinositol 5-phosphate 4-kinases (PIP4Ks) phosphorylate phosphatidylinositol 5-phosphate (PI5P) to generate phosphatidylinositol 4,5-bisphosphate; their most likely function is the regulation of the levels of PI5P, a putative signalling intermediate. There are three mammalian PIP4Ks isoforms (α, β and γ), but their physiological roles remain poorly understood. In the present study, we identified the zebrafish orthologue (zPIP4Kα) of the high-activity human PIP4K α isoform and analyzed its role in embryonic development. RT-PCR analysis and whole-mount in situ hybridization experiments showed that zPIP4Kα is maternally expressed. At later embryonic stages, high PIP4Kα expression was detected in the head and the pectoral fins. Knockdown of zPIP4Kα by antisense morpholino oligonucleotides led to severe morphological abnormalities, including midbody winding defects at 48hpf. The abnormal phenotype could be rescued, at least in large part, by injection of human PIP4Kα mRNA. Our results reveal a key role for PIP4Kα and its activity in vertebrate tissue homeostasis and organ development.
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Affiliation(s)
- Dalila Elouarrat
- Division of Cell Biology, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
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72
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Carayol N, Tran Van Nhieu G. Tips and tricks about Shigella invasion of epithelial cells. Curr Opin Microbiol 2013; 16:32-7. [PMID: 23318141 DOI: 10.1016/j.mib.2012.11.010] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2012] [Accepted: 11/26/2012] [Indexed: 02/08/2023]
Abstract
Shigella, the causative agent of bacillary dysentery, invades the colonic epithelium where it elicits an intense inflammation leading to tissular destruction. Key to bacterial virulence, type III effectors injected into host cells reorganize the actin cytoskeleton and regulate inflammatory responses. Much progress has been made recently in the characterization of these type III effectors. These findings have reshaped our view of Shigella invasion, suggesting a strategy to invade epithelial cells 'discretely' as an initial route of invasion, contrasting with the devastating inflammatory response associated with the disease's acute phase. The diverse roles of Shigella type III effectors highlight the complexity of an infection process where as little as a thousand bacteria are estimated sufficient to cause the disease in humans.
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Affiliation(s)
- Nathalie Carayol
- Equipe Communication Intercellulaire et Infections Microbiennes, Centre de Recherche Interdisciplinaire en Biologie, Collège de France, Paris, France
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73
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Gericke A, Leslie NR, Lösche M, Ross AH. PtdIns(4,5)P2-mediated cell signaling: emerging principles and PTEN as a paradigm for regulatory mechanism. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2013; 991:85-104. [PMID: 23775692 DOI: 10.1007/978-94-007-6331-9_6] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
PtdIns(4,5)P2 (phosphatidylinositol 4,5-bisphosphate) is a relatively common anionic lipid that regulates cellular functions by multiple mechanisms. Hydrolysis of PtdIns(4,5)P2 by phospholipase C yields inositol trisphosphate and diacylglycerol. Phosphorylation by phosphoinositide 3-kinase yields PtdIns(3,4,5)P3, which is a potent signal for survival and proliferation. Also, PtdIns(4,5)P2 can bind directly to integral and peripheral membrane proteins. As an example of regulation by PtdIns(4,5)P2, we discuss phosphatase and tensin homologue deleted on chromosome 10 (PTEN) in detail. PTEN is an important tumor suppressor and hydrolyzes PtdIns(3,4,5)P3. PtdIns(4,5)P2 enhances PTEN association with the plasma membrane and activates its phosphatase activity. This is a critical regulatory mechanism, but a detailed description of this process from a structural point of view is lacking. The disordered lipid bilayer environment hinders structural determinations of membrane-bound PTEN. A new method to analyze membrane-bound protein measures neutron reflectivity for proteins bound to tethered phospholipid membranes. These methods allow determination of the orientation and shape of membrane-bound proteins. In combination with molecular dynamics simulations, these studies will provide crucial structural information that can serve as a foundation for our understanding of PTEN regulation in normal and pathological processes.
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Affiliation(s)
- Arne Gericke
- Department of Chemistry and Biochemistry, Worcester Polytechnic Institute, Worcester, MA 01609, USA
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74
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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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75
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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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76
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In vivo, Pikfyve generates PI(3,5)P2, which serves as both a signaling lipid and the major precursor for PI5P. Proc Natl Acad Sci U S A 2012; 109:17472-7. [PMID: 23047693 DOI: 10.1073/pnas.1203106109] [Citation(s) in RCA: 163] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Mutations that cause defects in levels of the signaling lipid phosphatidylinositol 3,5-bisphosphate [PI(3,5)P(2)] lead to profound neurodegeneration in mice. Moreover, mutations in human FIG4 predicted to lower PI(3,5)P(2) levels underlie Charcot-Marie-Tooth type 4J neuropathy and are present in selected cases of amyotrophic lateral sclerosis. In yeast and mammals, PI(3,5)P(2) is generated by a protein complex that includes the lipid kinase Fab1/Pikfyve, the scaffolding protein Vac14, and the lipid phosphatase Fig4. Fibroblasts cultured from Vac14(-/-) and Fig4(-/-) mouse mutants have a 50% reduction in the levels of PI(3,5)P(2), suggesting that there may be PIKfyve-independent pathways that generate this lipid. Here, we characterize a Pikfyve gene-trap mouse (Pikfyve(β-geo/β-geo)), a hypomorph with ~10% of the normal level of Pikfyve protein. shRNA silencing of the residual Pikfyve transcript in fibroblasts demonstrated that Pikfyve is required to generate all of the PI(3,5)P(2) pool. Surprisingly, Pikfyve also is responsible for nearly all of the phosphatidylinositol-5-phosphate (PI5P) pool. We show that PI5P is generated directly from PI(3,5)P(2), likely via 3'-phosphatase activity. Analysis of tissues from the Pikfyve(β-geo/β-geo) mouse mutants reveals that Pikfyve is critical in neural tissues, heart, lung, kidney, thymus, and spleen. Thus, PI(3,5)P(2) and PI5P have major roles in multiple organs. Understanding the regulation of these lipids may provide insights into therapies for multiple diseases.
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77
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78
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Myotubularin phosphoinositide phosphatases: cellular functions and disease pathophysiology. Trends Mol Med 2012; 18:317-27. [DOI: 10.1016/j.molmed.2012.04.004] [Citation(s) in RCA: 108] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2012] [Revised: 04/10/2012] [Accepted: 04/12/2012] [Indexed: 11/23/2022]
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79
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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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80
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Viaud J, Gaits-Iacovoni F, Payrastre B. Regulation of the DH-PH tandem of guanine nucleotide exchange factor for Rho GTPases by phosphoinositides. Adv Biol Regul 2012; 52:303-14. [PMID: 22781744 DOI: 10.1016/j.jbior.2012.04.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2012] [Accepted: 04/04/2012] [Indexed: 10/28/2022]
Abstract
Rho GTPases act as molecular switches central in cellular processes such as cytoskeleton dynamics, migration, cell proliferation, growth or survival. Their activation is tightly regulated downstream of cell surface receptors by Guanine nucleotide Exchange Factors (GEFs), that are responsible for the specificity, the accuracy, and the spatial restriction of Rho GTPases response to extracellular cues. Because there is about four time more RhoGEFs that Rho GTPases, and GEFs do not always show a strict specificity for GTPases, it is clear that their regulation depends on specific interactions with the subcellular environment. RhoGEFs bear a peculiar structure, highly conserved though evolution, consisting of a DH-PH tandem, the DH (Dbl homology) domain being responsible for the exchange activity. The function of the PH (Pleckstrin homology) domain known to bind phosphoinositides, however, remains elusive, and reports are in many cases rather confusing. This review summarizes data on the regulation of RhoGEFs activity through interaction of the PH-associated DH domain with phosphoinositides which are considered as critical players in the spatial organization of major signaling pathways.
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Affiliation(s)
- Julien Viaud
- INSERM, UMR1048, Université Paul Sabatier, Institut des Maladies Métaboliques et Cardiovasculaires, I2MC, 1 Avenue Jean Poulhès, BP 84225, 31432 Toulouse Cedex 4, France
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81
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Tronchère H, Bolino A, Laporte J, Payrastre B. Myotubularins and associated neuromuscular diseases. ACTA ACUST UNITED AC 2012. [DOI: 10.2217/clp.12.7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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82
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Mayinger P. Phosphoinositides and vesicular membrane traffic. Biochim Biophys Acta Mol Cell Biol Lipids 2012; 1821:1104-13. [PMID: 22281700 DOI: 10.1016/j.bbalip.2012.01.002] [Citation(s) in RCA: 89] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2011] [Revised: 12/27/2011] [Accepted: 01/02/2012] [Indexed: 01/08/2023]
Abstract
Phosphoinositide lipids were initially discovered as precursors for specific second messengers involved in signal transduction, but have now taken the center stage in controlling many essential processes at virtually every cellular membrane. In particular, phosphoinositides play a critical role in regulating membrane dynamics and vesicular transport. The unique distribution of certain phosphoinositides at specific intracellular membranes makes these molecules uniquely suited to direct organelle-specific trafficking reactions. In this regulatory role, phosphoinositides cooperate specifically with small GTPases from the Arf and Rab families. This review will summarize recent progress in the study of phosphoinositides in membrane trafficking and organellar organization and highlight the particular relevance of these signaling pathways in disease. This article is part of a Special Issue entitled Lipids and Vesicular Transport.
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Affiliation(s)
- Peter Mayinger
- Division of Nephrology & Hypertension and Department of Cell & Developmental Biology, Oregon Health & Science University, Portland, OR 97239, USA.
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83
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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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84
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González-Díaz H, Munteanu CR, Postelnicu L, Prado-Prado F, Gestal M, Pazos A. LIBP-Pred: web server for lipid binding proteins using structural network parameters; PDB mining of human cancer biomarkers and drug targets in parasites and bacteria. MOLECULAR BIOSYSTEMS 2012; 8:851-62. [DOI: 10.1039/c2mb05432a] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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85
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Payrastre B, Gaits-Iacovoni F, Sansonetti P, Tronchère H. Phosphoinositides and cellular pathogens. Subcell Biochem 2012; 59:363-388. [PMID: 22374097 DOI: 10.1007/978-94-007-3015-1_12] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Phosphoinositides are considered as highly dynamic players in the spatiotemporal organization of key signaling pathways, actin cytoskeleton rearrangements, establishment of cell polarity and intracellular vesicle trafficking. Their metabolism is accurately controlled and mutations in several phosphoinositide metabolizing enzymes take part in the development of human pathologies. Interestingly, evidence is accumulating that modulation of the phosphoinositide metabolism is critical for pathogenicity and virulence of many human pathogens. Given the importance of phosphoinositides, which link membrane and cytoskeleton dynamics to cell responses, it is not surprising that many invasive pathogens hijack their metabolism as part of their strategies to establish infection. In fact, according to their lifestyle, cellular pathogens use the phosphoinositide metabolism in order to trigger their uptake in nonphagocytic cells and/or modulate the maturation of the pathogen-containing vacuole to establish their replicative niche or escape in the cytosol and promote host cell survival. The last two decades have been marked by the discovery of different tactics used by cellular pathogens to modulate the phosphoinositide metabolism as part of their strategies to survive, proliferate and disseminate in a hostile environment.
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Affiliation(s)
- Bernard Payrastre
- Inserm, U1048, Université Toulouse 3, I2MC, Hôpital de Toulouse, BP 84225 Avenue Jean Poulhès, 31432, Toulouse Cedex 04, France,
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Moravcevic K, Oxley CL, Lemmon MA. Conditional peripheral membrane proteins: facing up to limited specificity. Structure 2011; 20:15-27. [PMID: 22193136 DOI: 10.1016/j.str.2011.11.012] [Citation(s) in RCA: 134] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2011] [Revised: 11/22/2011] [Accepted: 11/23/2011] [Indexed: 11/30/2022]
Abstract
Regulated relocalization of signaling and trafficking proteins is crucial for the control of many cellular processes and is driven by a series of domains that respond to alterations at membrane surfaces. The first examples of these domains--conditional peripheral membrane proteins--included C1, C2, PH, PX, and FYVE domains, which specifically recognize single tightly regulated membrane components such as diacylglycerol or phosphoinositides. The structural basis for this recognition is now well understood. Efforts to identify additional domains with similar functions that bind other targets (or participate in unexplained cellular processes) have not yielded many more examples of specific phospholipid-binding domains. Instead, most of the recently discovered conditional peripheral membrane proteins bind multiple targets (each with limited specificity), relying on coincidence detection and/or recognizing broader physical properties of the membrane such as charge or curvature. This broader range of recognition modes presents significant methodological challenges for a full structural understanding.
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Affiliation(s)
- Katarina Moravcevic
- Department of Biochemistry and Biophysics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
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