1
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Kelty MT, Miron-Ocampo A, Beattie SR. A series of pyrimidine-based antifungals with anti-mold activity disrupt ER function in Aspergillus fumigatus. Microbiol Spectr 2024; 12:e0104524. [PMID: 38916314 PMCID: PMC11302339 DOI: 10.1128/spectrum.01045-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2024] [Accepted: 05/23/2024] [Indexed: 06/26/2024] Open
Abstract
Fungal infections are a major contributor to morbidity and mortality among immunocompromised populations. Moreover, fungal disease caused by molds are difficult to treat and are associated with particularly high mortality. To address the need for new mold-active antifungal drugs, we performed a high-throughput screen with Aspergillus fumigatus, the most common pathogenic mold. We identified a novel, pyrimidine-based chemical scaffold with broad-spectrum antifungal activity including activity against several difficult-to-treat molds. A chemical genetics screen of Saccharomyces cerevisiae suggested that this compound may target the endoplasmic reticulum (ER) and perturb ER function and/or homeostasis. Consistent with this model, this compound induces the unfolded protein response and inhibits secretion of A. fumigatus collagenases. Initial cytotoxicity and pharmacokinetic studies show favorable features including limited mammalian cell toxicity and bioavailability in vivo. Together, these data support the further medicinal chemistry and pre-clinical development of this pyrimidine scaffold toward more effective treatments for life-threatening invasive mold infections.IMPORTANCEInvasive fungal diseases are life-threatening infections caused by fungi in immunocompromised individuals. Currently, there are only three major classes of antifungal drugs available to treat fungal infections; however, these options are becoming even more limited with the global emergence of antifungal drug resistance. To address the need for new antifungal therapies, we performed a screen of chemical compounds and identified a novel molecule with antifungal activity. Initial characterization of this compound shows drug-like features and broad-spectrum activity against medically important fungi. Together, our results support the continued development of this compound as a potential future therapy for these devastating fungal infections.
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Affiliation(s)
- Martin T. Kelty
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Aracely Miron-Ocampo
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Sarah R. Beattie
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
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2
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Caligaris M, Sampaio-Marques B, Hatakeyama R, Pillet B, Ludovico P, De Virgilio C, Winderickx J, Nicastro R. The Yeast Protein Kinase Sch9 Functions as a Central Nutrient-Responsive Hub That Calibrates Metabolic and Stress-Related Responses. J Fungi (Basel) 2023; 9:787. [PMID: 37623558 PMCID: PMC10455444 DOI: 10.3390/jof9080787] [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: 05/30/2023] [Revised: 07/20/2023] [Accepted: 07/24/2023] [Indexed: 08/26/2023] Open
Abstract
Yeast cells are equipped with different nutrient signaling pathways that enable them to sense the availability of various nutrients and adjust metabolism and growth accordingly. These pathways are part of an intricate network since most of them are cross-regulated and subject to feedback regulation at different levels. In yeast, a central role is played by Sch9, a protein kinase that functions as a proximal effector of the conserved growth-regulatory TORC1 complex to mediate information on the availability of free amino acids. However, recent studies established that Sch9 is more than a TORC1-effector as its activity is tuned by several other kinases. This allows Sch9 to function as an integrator that aligns different input signals to achieve accuracy in metabolic responses and stress-related molecular adaptations. In this review, we highlight the latest findings on the structure and regulation of Sch9, as well as its role as a nutrient-responsive hub that impacts on growth and longevity of yeast cells. Given that most key players impinging on Sch9 are well-conserved, we also discuss how studies on Sch9 can be instrumental to further elucidate mechanisms underpinning healthy aging in mammalians.
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Affiliation(s)
- Marco Caligaris
- Department of Biology, University of Fribourg, 1700 Fribourg, Switzerland; (M.C.); (B.P.); (C.D.V.)
| | - Belém Sampaio-Marques
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, 4710-057 Braga, Portugal; (B.S.-M.); (P.L.)
- ICVS/3B’s-PT Government Associate Laboratory, 4806-909 Guimarães, Portugal
| | - Riko Hatakeyama
- Institute of Medical Sciences, University of Aberdeen, Aberdeen AB25 2ZD, UK;
| | - Benjamin Pillet
- Department of Biology, University of Fribourg, 1700 Fribourg, Switzerland; (M.C.); (B.P.); (C.D.V.)
| | - Paula Ludovico
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, 4710-057 Braga, Portugal; (B.S.-M.); (P.L.)
- ICVS/3B’s-PT Government Associate Laboratory, 4806-909 Guimarães, Portugal
| | - Claudio De Virgilio
- Department of Biology, University of Fribourg, 1700 Fribourg, Switzerland; (M.C.); (B.P.); (C.D.V.)
| | - Joris Winderickx
- Department of Biology, Functional Biology, KU Leuven, B-3001 Heverlee, Belgium;
| | - Raffaele Nicastro
- Department of Biology, University of Fribourg, 1700 Fribourg, Switzerland; (M.C.); (B.P.); (C.D.V.)
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3
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Salita T, Rustam YH, Hofferek V, Jackson M, Tollestrup I, Sheridan JP, Schramm VL, Evans GB, Reid GE, Munkacsi AB. Phosphoinositide and redox dysregulation by the anticancer methylthioadenosine phosphorylase transition state inhibitor. Biochim Biophys Acta Mol Cell Biol Lipids 2023:159346. [PMID: 37301365 DOI: 10.1016/j.bbalip.2023.159346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Revised: 05/05/2023] [Accepted: 05/29/2023] [Indexed: 06/12/2023]
Abstract
Methylthio-DADMe-immucillin-A (MTDIA) is an 86 picomolar inhibitor of 5'-methylthioadenosine phosphorylase (MTAP) with potent and specific anti-cancer efficacy. MTAP salvages S-adenosylmethionine (SAM) from 5'-methylthioadenosine (MTA), a toxic metabolite produced during polyamine biosynthesis. Changes in MTAP expression are implicated in cancer growth and development, making MTAP an appealing target for anti-cancer therapeutics. Since SAM is involved in lipid metabolism, we hypothesised that MTDIA alters the lipidomes of MTDIA-treated cells. To identify these effects, we analysed the lipid profiles of MTDIA-treated Saccharomyces cerevisiae using ultra-high resolution accurate mass spectrometry (UHRAMS). MTAP inhibition by MTDIA, and knockout of the Meu1 gene that encodes for MTAP in yeast, caused global lipidomic changes and differential abundance of lipids involved in cell signaling. The phosphoinositide kinase/phosphatase signaling network was specifically impaired upon MTDIA treatment, and was independently validated and further characterised via altered localization of proteins integral to this network. Functional consequences of dysregulated lipid metabolism included a decrease in reactive oxygen species (ROS) levels induced by MTDIA that was contemporaneous with changes in immunological response factors (nitric oxide, tumour necrosis factor-alpha and interleukin-10) in mammalian cells. These results indicate that lipid homeostasis alterations and concomitant downstream effects may be associated with MTDIA mechanistic efficacy.
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Affiliation(s)
- Timothy Salita
- School of Biological Sciences, Victoria University of Wellington, Wellington, New Zealand; Department of Biochemistry and Pharmacology, University of Melbourne, Parkville, Australia
| | - Yepy H Rustam
- Department of Biochemistry and Pharmacology, University of Melbourne, Parkville, Australia
| | - Vinzenz Hofferek
- School of Chemistry, University of Melbourne, Parkville, Australia
| | - Michael Jackson
- School of Biological Sciences, Victoria University of Wellington, Wellington, New Zealand
| | - Isaac Tollestrup
- School of Biological Sciences, Victoria University of Wellington, Wellington, New Zealand
| | - Jeffrey P Sheridan
- School of Biological Sciences, Victoria University of Wellington, Wellington, New Zealand
| | - Vern L Schramm
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Gary B Evans
- Ferrier Research Institute, Victoria University of Wellington, Wellington, New Zealand
| | - Gavin E Reid
- Department of Biochemistry and Pharmacology, University of Melbourne, Parkville, Australia; School of Chemistry, University of Melbourne, Parkville, Australia; Bio21 Molecular Science & Biotechnology Institute, University of Melbourne, Parkville, Australia
| | - Andrew B Munkacsi
- School of Biological Sciences, Victoria University of Wellington, Wellington, New Zealand.
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4
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Jensen JB, Falkenburger BH, Dickson EJ, de la Cruz L, Dai G, Myeong J, Jung SR, Kruse M, Vivas O, Suh BC, Hille B. Biophysical physiology of phosphoinositide rapid dynamics and regulation in living cells. J Gen Physiol 2022; 154:e202113074. [PMID: 35583815 PMCID: PMC9121023 DOI: 10.1085/jgp.202113074] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Accepted: 04/28/2022] [Indexed: 01/07/2023] Open
Abstract
Phosphoinositide membrane lipids are ubiquitous low-abundance signaling molecules. They direct many physiological processes that involve ion channels, membrane identification, fusion of membrane vesicles, and vesicular endocytosis. Pools of these lipids are continually broken down and refilled in living cells, and the rates of some of these reactions are strongly accelerated by physiological stimuli. Recent biophysical experiments described here measure and model the kinetics and regulation of these lipid signals in intact cells. Rapid on-line monitoring of phosphoinositide metabolism is made possible by optical tools and electrophysiology. The experiments reviewed here reveal that as for other cellular second messengers, the dynamic turnover and lifetimes of membrane phosphoinositides are measured in seconds, controlling and timing rapid physiological responses, and the signaling is under strong metabolic regulation. The underlying mechanisms of this metabolic regulation remain questions for the future.
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Affiliation(s)
- Jill B. Jensen
- Department of Physiology and Biophysics, University of Washington, Seattle, WA
| | | | - Eamonn J. Dickson
- Department of Physiology and Membrane Biology, University of California, Davis, Davis, CA
| | - Lizbeth de la Cruz
- Department of Physiology and Biophysics, University of Washington, Seattle, WA
| | - Gucan Dai
- Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, MO
| | - Jongyun Myeong
- Department of Cell Biology and Physiology, Washington University in St. Louis, St. Louis, MO
| | | | - Martin Kruse
- Department of Biology and Program in Neuroscience, Bates College, Lewiston, ME
| | - Oscar Vivas
- Department of Physiology and Biophysics, University of Washington, Seattle, WA
| | - Byung-Chang Suh
- Department of Brain Sciences, Daegu Gyeongbuk Institute of Science and Technology, Daegu, Republic of Korea
| | - Bertil Hille
- Department of Physiology and Biophysics, University of Washington, Seattle, WA
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5
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Spolaor S, Rovetta M, Nobile MS, Cazzaniga P, Tisi R, Besozzi D. Modeling Calcium Signaling in S. cerevisiae Highlights the Role and Regulation of the Calmodulin-Calcineurin Pathway in Response to Hypotonic Shock. Front Mol Biosci 2022; 9:856030. [PMID: 35664674 PMCID: PMC9158465 DOI: 10.3389/fmolb.2022.856030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2022] [Accepted: 04/04/2022] [Indexed: 01/17/2023] Open
Abstract
Calcium homeostasis and signaling processes in Saccharomyces cerevisiae, as well as in any eukaryotic organism, depend on various transporters and channels located on both the plasma and intracellular membranes. The activity of these proteins is regulated by a number of feedback mechanisms that act through the calmodulin-calcineurin pathway. When exposed to hypotonic shock (HTS), yeast cells respond with an increased cytosolic calcium transient, which seems to be conditioned by the opening of stretch-activated channels. To better understand the role of each channel and transporter involved in the generation and recovery of the calcium transient—and of their feedback regulations—we defined and analyzed a mathematical model of the calcium signaling response to HTS in yeast cells. The model was validated by comparing the simulation outcomes with calcium concentration variations before and during the HTS response, which were observed experimentally in both wild-type and mutant strains. Our results show that calcium normally enters the cell through the High Affinity Calcium influx System and mechanosensitive channels. The increase of the plasma membrane tension, caused by HTS, boosts the opening probability of mechanosensitive channels. This event causes a sudden calcium pulse that is rapidly dissipated by the activity of the vacuolar transporter Pmc1. According to model simulations, the role of another vacuolar transporter, Vcx1, is instead marginal, unless calcineurin is inhibited or removed. Our results also suggest that the mechanosensitive channels are subject to a calcium-dependent feedback inhibition, possibly involving calmodulin. Noteworthy, the model predictions are in accordance with literature results concerning some aspects of calcium homeostasis and signaling that were not specifically addressed within the model itself, suggesting that it actually depicts all the main cellular components and interactions that constitute the HTS calcium pathway, and thus can correctly reproduce the shaping of the calcium signature by calmodulin- and calcineurin-dependent complex regulations. The model predictions also allowed to provide an interpretation of different regulatory schemes involved in calcium handling in both wild-type and mutants yeast strains. The model could be easily extended to represent different calcium signals in other eukaryotic cells.
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Affiliation(s)
- Simone Spolaor
- Department of Informatics, Systems and Communication, University of Milano-Bicocca, Milan, Italy
| | - Mattia Rovetta
- Department of Informatics, Systems and Communication, University of Milano-Bicocca, Milan, Italy
| | - Marco S. Nobile
- Department of Environmental Sciences, Informatics and Statistics, Ca’ Foscari University of Venice, Venice, Italy
- Bicocca Bioinformatics, Biostatistics and Bioimaging Centre—B4, Milan, Italy
- SYSBIO/ISBE.IT Centre of Systems Biology, Milan, Italy
| | - Paolo Cazzaniga
- Bicocca Bioinformatics, Biostatistics and Bioimaging Centre—B4, Milan, Italy
- SYSBIO/ISBE.IT Centre of Systems Biology, Milan, Italy
- Department of Human and Social Sciences, University of Bergamo, Bergamo, Italy
| | - Renata Tisi
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Milan, Italy
- *Correspondence: Renata Tisi, ; Daniela Besozzi,
| | - Daniela Besozzi
- Department of Informatics, Systems and Communication, University of Milano-Bicocca, Milan, Italy
- Bicocca Bioinformatics, Biostatistics and Bioimaging Centre—B4, Milan, Italy
- SYSBIO/ISBE.IT Centre of Systems Biology, Milan, Italy
- *Correspondence: Renata Tisi, ; Daniela Besozzi,
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6
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De Camilli P. How a first research experience had an impact on my scientific journey. Mol Biol Cell 2021; 32:ae1. [PMID: 34735266 PMCID: PMC8694089 DOI: 10.1091/mbc.e21-08-0397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
As I look back to my scientific trajectory on the occasion of being the recipient of the E. B. Wilson Medal of the American Society for Cell Biology, I realize how much an early scientific experience had an impact on my research many years later. The major influence that the first scientific encounters can have in defining a scientist’s path makes the choice of the training environment so important for a future career.
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Affiliation(s)
- Pietro De Camilli
- Departments of Neuroscience and Cell Biology, Howard Hughes Medical Institute, Program in Cellular Neuroscience, Neurodegeneration and Repair, Kavli Institute for Neuroscience, Yale School of Medicine, New Haven, CT 06510
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7
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Fat of the Gut: Epithelial Phospholipids in Inflammatory Bowel Diseases. Int J Mol Sci 2021; 22:ijms222111682. [PMID: 34769112 PMCID: PMC8584226 DOI: 10.3390/ijms222111682] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 10/20/2021] [Accepted: 10/27/2021] [Indexed: 12/15/2022] Open
Abstract
Inflammatory bowel diseases (IBD) comprise a distinct set of clinical symptoms resulting from chronic inflammation within the gastrointestinal (GI) tract. Despite the significant progress in understanding the etiology and development of treatment strategies, IBD remain incurable for thousands of patients. Metabolic deregulation is indicative of IBD, including substantial shifts in lipid metabolism. Recent data showed that changes in some phospholipids are very common in IBD patients. For instance, phosphatidylcholine (PC)/phosphatidylethanolamine (PE) and lysophosphatidylcholine (LPC)/PC ratios are associated with the severity of the inflammatory process. Composition of phospholipids also changes upon IBD towards an increase in arachidonic acid and a decrease in linoleic and a-linolenic acid levels. Moreover, an increase in certain phospholipid metabolites, such as lysophosphatidylcholine, sphingosine-1-phosphate and ceramide, can result in enhanced intestinal inflammation, malignancy, apoptosis or necroptosis. Because some phospholipids are associated with pathogenesis of IBD, they may provide a basis for new strategies to treat IBD. Current attempts are aimed at controlling phospholipid and fatty acid levels through the diet or via pharmacological manipulation of lipid metabolism.
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8
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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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9
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The distribution of phosphatidylinositol 4,5-bisphosphate in the budding yeast plasma membrane. Histochem Cell Biol 2021; 156:109-121. [PMID: 34052862 DOI: 10.1007/s00418-021-01989-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/17/2021] [Indexed: 01/07/2023]
Abstract
Phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P2) is generated through phosphorylation of phosphatidylinositol 4-phosphate (PtdIns(4)P) by Mss4p, the only PtdIns phosphate 5-kinase in yeast cells. PtdIns(4,5)P2 is involved in various kinds of yeast functions. PtdIns(4)P is not only the immediate precursor of PtdIns(4,5)P2, but also an essential signaling molecule in the plasma membrane, Golgi, and endosomal system. To analyze the distribution of PtdIns(4,5)P2 and PtdIns(4)P in the yeast plasma membrane at a nanoscale level, we employed a freeze-fracture electron microscopy (EM) method that physically immobilizes lipid molecules in situ. It has been reported that the plasma membrane of budding yeast can be divided into three distinct areas: furrowed, hexagonal, and undifferentiated flat. Previously, using the freeze-fracture EM method, we determined that PtdIns(4)P is localized in the undifferentiated flat area, avoiding the furrowed and hexagonal areas of the plasma membrane. In the present study, we found that PtdIns(4,5)P2 was localized in the cytoplasmic leaflet of the plasma membrane, and concentrated in the furrowed area. There are three types of PtdIns 4-kinases which are encoded by stt4, pik1, and lsb6. The labeling density of PtdIns(4)P in the plasma membrane significantly decreased in both pik1ts and stt4ts mutants. However, the labeling densities of PtdIns(4,5)P2 in the plasma membrane of both the pik1ts and stt4ts mutants were comparable to that of the wild type yeast. These results suggest that PtdIns(4)P produced by either Pik1p or Stt4p is immediately phosphorylated by Mss4p and converted to PtdIns(4,5)P2 at the plasma membrane.
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10
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Kobylarz MJ, Goodwin JM, Kang ZB, Annand JW, Hevi S, O’Mahony E, McAllister G, Reece-Hoyes J, Wang Q, Alford J, Russ C, Lindeman A, Beibel M, Roma G, Carbone W, Knehr J, Loureiro J, Antczak C, Wiederschain D, Murphy LO, Menon S, Nyfeler B. An iron-dependent metabolic vulnerability underlies VPS34-dependence in RKO cancer cells. PLoS One 2020; 15:e0235551. [PMID: 32833964 PMCID: PMC7446895 DOI: 10.1371/journal.pone.0235551] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Accepted: 06/18/2020] [Indexed: 12/12/2022] Open
Abstract
VPS34 is a key regulator of endomembrane dynamics and cargo trafficking, and is essential in cultured cell lines and in mice. To better characterize the role of VPS34 in cell growth, we performed unbiased cell line profiling studies with the selective VPS34 inhibitor PIK-III and identified RKO as a VPS34-dependent cellular model. Pooled CRISPR screen in the presence of PIK-III revealed endolysosomal genes as genetic suppressors. Dissecting VPS34-dependent alterations with transcriptional profiling, we found the induction of hypoxia response and cholesterol biosynthesis as key signatures. Mechanistically, acute VPS34 inhibition enhanced lysosomal degradation of transferrin and low-density lipoprotein receptors leading to impaired iron and cholesterol uptake. Excess soluble iron, but not cholesterol, was sufficient to partially rescue the effects of VPS34 inhibition on mitochondrial respiration and cell growth, indicating that iron limitation is the primary driver of VPS34-dependency in RKO cells. Loss of RAB7A, an endolysosomal marker and top suppressor in our genetic screen, blocked transferrin receptor degradation, restored iron homeostasis and reversed the growth defect as well as metabolic alterations due to VPS34 inhibition. Altogether, our findings suggest that impaired iron mobilization via the VPS34-RAB7A axis drive VPS34-dependence in certain cancer cells.
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Affiliation(s)
- Marek J. Kobylarz
- Novartis Institutes for Biomedical Research, Cambridge, MA, United States of America
| | - Jonathan M. Goodwin
- Novartis Institutes for Biomedical Research, Cambridge, MA, United States of America
| | - Zhao B. Kang
- Novartis Institutes for Biomedical Research, Cambridge, MA, United States of America
| | - John W. Annand
- Novartis Institutes for Biomedical Research, Cambridge, MA, United States of America
| | - Sarah Hevi
- Novartis Institutes for Biomedical Research, Cambridge, MA, United States of America
| | - Ellen O’Mahony
- Novartis Institutes for Biomedical Research, Cambridge, MA, United States of America
| | - Gregory McAllister
- Novartis Institutes for Biomedical Research, Cambridge, MA, United States of America
| | - John Reece-Hoyes
- Novartis Institutes for Biomedical Research, Cambridge, MA, United States of America
| | - Qiong Wang
- Novartis Institutes for Biomedical Research, Cambridge, MA, United States of America
| | - John Alford
- Novartis Institutes for Biomedical Research, Cambridge, MA, United States of America
| | - Carsten Russ
- Novartis Institutes for Biomedical Research, Cambridge, MA, United States of America
| | - Alicia Lindeman
- Novartis Institutes for Biomedical Research, Cambridge, MA, United States of America
| | - Martin Beibel
- Novartis Institutes for Biomedical Research, Basel, Switzerland
| | - Guglielmo Roma
- Novartis Institutes for Biomedical Research, Basel, Switzerland
| | - Walter Carbone
- Novartis Institutes for Biomedical Research, Basel, Switzerland
| | - Judith Knehr
- Novartis Institutes for Biomedical Research, Basel, Switzerland
| | - Joseph Loureiro
- Novartis Institutes for Biomedical Research, Cambridge, MA, United States of America
| | - Christophe Antczak
- Novartis Institutes for Biomedical Research, Cambridge, MA, United States of America
| | - Dmitri Wiederschain
- Novartis Institutes for Biomedical Research, Cambridge, MA, United States of America
| | - Leon O. Murphy
- Novartis Institutes for Biomedical Research, Cambridge, MA, United States of America
| | - Suchithra Menon
- Novartis Institutes for Biomedical Research, Cambridge, MA, United States of America
- * E-mail: (SM); (BN)
| | - Beat Nyfeler
- Novartis Institutes for Biomedical Research, Basel, Switzerland
- * E-mail: (SM); (BN)
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11
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Athanasopoulos A, André B, Sophianopoulou V, Gournas C. Fungal plasma membrane domains. FEMS Microbiol Rev 2020; 43:642-673. [PMID: 31504467 DOI: 10.1093/femsre/fuz022] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Accepted: 08/25/2019] [Indexed: 12/11/2022] Open
Abstract
The plasma membrane (PM) performs a plethora of physiological processes, the coordination of which requires spatial and temporal organization into specialized domains of different sizes, stability, protein/lipid composition and overall architecture. Compartmentalization of the PM has been particularly well studied in the yeast Saccharomyces cerevisiae, where five non-overlapping domains have been described: The Membrane Compartments containing the arginine permease Can1 (MCC), the H+-ATPase Pma1 (MCP), the TORC2 kinase (MCT), the sterol transporters Ltc3/4 (MCL), and the cell wall stress mechanosensor Wsc1 (MCW). Additional cortical foci at the fungal PM are the sites where clathrin-dependent endocytosis occurs, the sites where the external pH sensing complex PAL/Rim localizes, and sterol-rich domains found in apically grown regions of fungal membranes. In this review, we summarize knowledge from several fungal species regarding the organization of the lateral PM segregation. We discuss the mechanisms of formation of these domains, and the mechanisms of partitioning of proteins there. Finally, we discuss the physiological roles of the best-known membrane compartments, including the regulation of membrane and cell wall homeostasis, apical growth of fungal cells and the newly emerging role of MCCs as starvation-protective membrane domains.
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Affiliation(s)
- Alexandros Athanasopoulos
- Microbial Molecular Genetics Laboratory, Institute of Biosciences and Applications, National Centre for Scientific Research 'Demokritos,' Patr. Grigoriou E & 27 Neapoleos St. 15341, Agia Paraskevi, Greece
| | - Bruno André
- Molecular Physiology of the Cell laboratory, Université Libre de Bruxelles (ULB), Institut de Biologie et de Médecine Moléculaires, rue des Pr Jeener et Brachet 12, 6041, Gosselies, Belgium
| | - Vicky Sophianopoulou
- Microbial Molecular Genetics Laboratory, Institute of Biosciences and Applications, National Centre for Scientific Research 'Demokritos,' Patr. Grigoriou E & 27 Neapoleos St. 15341, Agia Paraskevi, Greece
| | - Christos Gournas
- Microbial Molecular Genetics Laboratory, Institute of Biosciences and Applications, National Centre for Scientific Research 'Demokritos,' Patr. Grigoriou E & 27 Neapoleos St. 15341, Agia Paraskevi, Greece
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12
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Kumar A, Ahmad A, Vyawahare A, Khan R. Membrane Trafficking and Subcellular Drug Targeting Pathways. Front Pharmacol 2020; 11:629. [PMID: 32536862 PMCID: PMC7267071 DOI: 10.3389/fphar.2020.00629] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Accepted: 04/21/2020] [Indexed: 12/29/2022] Open
Abstract
The movement of micro and macro molecules into and within a cell significantly governs several of their pharmacokinetic and pharmacodynamic parameters, thus regulating the cellular response to exogenous and endogenous stimuli. Trafficking of various pharmacological agents and other bioactive molecules throughout and within the cell is necessary for the fidelity of the cells but has been poorly investigated. Novel strategies against cancer and microbial infections need a deeper understanding of membrane as well as subcellular trafficking pathways and essentially regulate several aspects of the initiation and spread of anti-microbial and anti-cancer drug resistance. Furthermore, in order to avail the maximum possible bioavailability and therapeutic efficacy and to restrict the unwanted toxicity of pharmacological bioactives, these sometimes need to be functionalized with targeting ligands to regulate the subcellular trafficking and to enhance the localization. In the recent past the scenario drug targeting has primarily focused on targeting tissue components and cell vicinities, however, it is the membranous and subcellular trafficking system that directs the molecules to plausible locations. The effectiveness of the delivery platforms largely depends on their physicochemical nature, intracellular barriers, and biodistribution of the drugs, pharmacokinetics and pharmacodynamic paradigms. Most subcellular organelles possess some peculiar characteristics by which membranous and subcellular targeting can be manipulated, such as negative transmembrane potential in mitochondria, intraluminal delta pH in a lysosome, and many others. Many specialized methods, which positively promote the subcellular targeting and restrict the off-targeting of the bioactive molecules, exist. Recent advancements in designing the carrier molecules enable the handling of membrane trafficking to facilitate the delivery of active compounds to subcellular localizations. This review aims to cover membrane trafficking pathways which promote the delivery of the active molecule in to the subcellular locations, the associated pathways of the subcellular drug delivery system, and the role of the carrier system in drug delivery techniques.
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Affiliation(s)
- Ajay Kumar
- Department of Nano-Therapeutics, Institute of Nano Science and Technology, Mohali, India
| | - Anas Ahmad
- Department of Nano-Therapeutics, Institute of Nano Science and Technology, Mohali, India
| | - Akshay Vyawahare
- Department of Nano-Therapeutics, Institute of Nano Science and Technology, Mohali, India
| | - Rehan Khan
- Department of Nano-Therapeutics, Institute of Nano Science and Technology, Mohali, India
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13
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Baksheeva VE, Nemashkalova EL, Firsov AM, Zalevsky AO, Vladimirov VI, Tikhomirova NK, Philippov PP, Zamyatnin AA, Zinchenko DV, Antonenko YN, Permyakov SE, Zernii EY. Membrane Binding of Neuronal Calcium Sensor-1: Highly Specific Interaction with Phosphatidylinositol-3-Phosphate. Biomolecules 2020; 10:biom10020164. [PMID: 31973069 PMCID: PMC7072451 DOI: 10.3390/biom10020164] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Revised: 01/15/2020] [Accepted: 01/17/2020] [Indexed: 12/20/2022] Open
Abstract
Neuronal calcium sensors are a family of N-terminally myristoylated membrane-binding proteins possessing a different intracellular localization and thereby targeting unique signaling partner(s). Apart from the myristoyl group, the membrane attachment of these proteins may be modulated by their N-terminal positively charged residues responsible for specific recognition of the membrane components. Here, we examined the interaction of neuronal calcium sensor-1 (NCS-1) with natural membranes of different lipid composition as well as individual phospholipids in form of multilamellar liposomes or immobilized monolayers and characterized the role of myristoyl group and N-terminal lysine residues in membrane binding and phospholipid preference of the protein. NCS-1 binds to photoreceptor and hippocampal membranes in a Ca2+-independent manner and the binding is attenuated in the absence of myristoyl group. Meanwhile, the interaction with photoreceptor membranes is less dependent on myristoylation and more sensitive to replacement of K3, K7, and/or K9 of NCS-1 by glutamic acid, reflecting affinity of the protein to negatively charged phospholipids. Consistently, among the major phospholipids, NCS-1 preferentially interacts with phosphatidylserine and phosphatidylinositol with micromolar affinity and the interaction with the former is inhibited upon mutating of N-terminal lysines of the protein. Remarkably, NCS-1 demonstrates pronounced specific binding to phosphoinositides with high preference for phosphatidylinositol-3-phosphate. The binding does not depend on myristoylation and, unexpectedly, is not sensitive to the charge inversion mutations. Instead, phosphatidylinositol-3-phosphate can be recognized by a specific site located in the N-terminal region of the protein. These data provide important novel insights into the general mechanism of membrane binding of NCS-1 and its targeting to specific phospholipids ensuring involvement of the protein in phosphoinositide-regulated signaling pathways.
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Affiliation(s)
- Viktoriia E. Baksheeva
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119992 Moscow, Russia; (V.E.B.); (A.M.F.); (N.K.T.); (P.P.P.); (Y.N.A.)
| | - Ekaterina L. Nemashkalova
- Institute for Biological Instrumentation of the Russian Academy of Sciences, Pushchino, 142290 Moscow Region, Russia; (E.L.N.); (S.E.P.)
| | - Alexander M. Firsov
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119992 Moscow, Russia; (V.E.B.); (A.M.F.); (N.K.T.); (P.P.P.); (Y.N.A.)
| | - Arthur O. Zalevsky
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, 119992 Moscow, Russia;
- Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry of the Russian Academy of Sciences, 117997 Moscow, Russia
- Institute of Molecular Medicine, Sechenov First Moscow State Medical University, 119991 Moscow, Russia
| | - Vasily I. Vladimirov
- Branch of Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry of the Russian Academy of Sciences in Pushchino, Pushchino, 142290 Moscow Region, Russia; (V.I.V.); (D.V.Z.)
| | - Natalia K. Tikhomirova
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119992 Moscow, Russia; (V.E.B.); (A.M.F.); (N.K.T.); (P.P.P.); (Y.N.A.)
| | - Pavel P. Philippov
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119992 Moscow, Russia; (V.E.B.); (A.M.F.); (N.K.T.); (P.P.P.); (Y.N.A.)
| | - Andrey A. Zamyatnin
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119992 Moscow, Russia; (V.E.B.); (A.M.F.); (N.K.T.); (P.P.P.); (Y.N.A.)
- Institute of Molecular Medicine, Sechenov First Moscow State Medical University, 119991 Moscow, Russia
| | - Dmitry V. Zinchenko
- Branch of Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry of the Russian Academy of Sciences in Pushchino, Pushchino, 142290 Moscow Region, Russia; (V.I.V.); (D.V.Z.)
| | - Yuri N. Antonenko
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119992 Moscow, Russia; (V.E.B.); (A.M.F.); (N.K.T.); (P.P.P.); (Y.N.A.)
| | - Sergey E. Permyakov
- Institute for Biological Instrumentation of the Russian Academy of Sciences, Pushchino, 142290 Moscow Region, Russia; (E.L.N.); (S.E.P.)
| | - Evgeni Yu. Zernii
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119992 Moscow, Russia; (V.E.B.); (A.M.F.); (N.K.T.); (P.P.P.); (Y.N.A.)
- Institute of Molecular Medicine, Sechenov First Moscow State Medical University, 119991 Moscow, Russia
- Correspondence: ; Tel.: +7-495-939-2344
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14
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Kwiatek JM, Han GS, Carman GM. Phosphatidate-mediated regulation of lipid synthesis at the nuclear/endoplasmic reticulum membrane. Biochim Biophys Acta Mol Cell Biol Lipids 2020; 1865:158434. [PMID: 30910690 PMCID: PMC6755077 DOI: 10.1016/j.bbalip.2019.03.006] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Accepted: 03/14/2019] [Indexed: 12/11/2022]
Abstract
In yeast and higher eukaryotes, phospholipids and triacylglycerol are derived from phosphatidate at the nuclear/endoplasmic reticulum membrane. In de novo biosynthetic pathways, phosphatidate is channeled into membrane phospholipids via its conversion to CDP-diacylglycerol. Its dephosphorylation to diacylglycerol is required for the synthesis of triacylglycerol as well as for the synthesis of phosphatidylcholine and phosphatidylethanolamine via the Kennedy pathway. In addition to the role of phosphatidate as a precursor, it is a regulatory molecule in the transcriptional control of phospholipid synthesis genes via the Henry regulatory circuit. Pah1 phosphatidate phosphatase and Dgk1 diacylglycerol kinase are key players that function counteractively in the control of the phosphatidate level at the nuclear/endoplasmic reticulum membrane. Loss of Pah1 phosphatidate phosphatase activity not only affects triacylglycerol synthesis but also disturbs the balance of the phosphatidate level, resulting in the alteration of lipid synthesis and related cellular defects. The pah1Δ phenotypes requiring Dgk1 diacylglycerol kinase exemplify the importance of the phosphatidate level in the misregulation of cellular processes. The catalytic function of Pah1 requires its translocation from the cytoplasm to the nuclear/endoplasmic reticulum membrane, which is regulated through its phosphorylation in the cytoplasm by multiple protein kinases as well as through its dephosphorylation by the membrane-associated Nem1-Spo7 protein phosphatase complex. This article is part of a Special Issue entitled Endoplasmic reticulum platforms for lipid dynamics edited by Shamshad Cockcroft and Christopher Stefan.
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Affiliation(s)
- Joanna M Kwiatek
- Department of Food Science and the Rutgers Center for Lipid Research, New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, NJ 08901, USA
| | - Gil-Soo Han
- Department of Food Science and the Rutgers Center for Lipid Research, New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, NJ 08901, USA
| | - George M Carman
- Department of Food Science and the Rutgers Center for Lipid Research, New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, NJ 08901, USA.
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15
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Cernikova L, Faso C, Hehl AB. Roles of Phosphoinositides and Their binding Proteins in Parasitic Protozoa. Trends Parasitol 2019; 35:996-1008. [PMID: 31615721 DOI: 10.1016/j.pt.2019.08.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Revised: 08/26/2019] [Accepted: 08/28/2019] [Indexed: 12/16/2022]
Abstract
Phosphoinositides (or phosphatidylinositol phosphates, PIPs) are low-abundance membrane phospholipids that act, in conjunction with their binding partners, as important constitutive signals defining biochemical organelle identity as well as membrane trafficking and signal transduction at eukaryotic cellular membranes. In this review, we present roles for PIP residues and PIP-binding proteins in endocytosis and autophagy in protist parasites such as Trypanosoma brucei, Toxoplasma gondii, Plasmodium falciparum, Entamoeba histolytica, and Giardia lamblia. Molecular parasitologists with an interest in comparative cell and molecular biology of membrane trafficking in protist lineages beyond the phylum Apicomplexa, along with cell and molecular biologists generally interested in the diversification of membrane trafficking in eukaryotes, will hopefully find this review to be a useful resource.
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Affiliation(s)
- Lenka Cernikova
- Institute of Parasitology, University of Zurich (ZH), Zurich, Switzerland
| | - Carmen Faso
- Institute of Parasitology, University of Zurich (ZH), Zurich, Switzerland; Institute of Cell Biology, University of Bern (BE), Bern, Switzerland
| | - Adrian B Hehl
- Institute of Parasitology, University of Zurich (ZH), Zurich, Switzerland.
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16
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Nakada-Tsukui K, Watanabe N, Maehama T, Nozaki T. Phosphatidylinositol Kinases and Phosphatases in Entamoeba histolytica. Front Cell Infect Microbiol 2019; 9:150. [PMID: 31245297 PMCID: PMC6563779 DOI: 10.3389/fcimb.2019.00150] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2018] [Accepted: 04/23/2019] [Indexed: 12/11/2022] Open
Abstract
Phosphatidylinositol (PtdIns) metabolism is indispensable in eukaryotes. Phosphoinositides (PIs) are phosphorylated derivatives of PtdIns and consist of seven species generated by reversible phosphorylation of the inositol moieties at the positions 3, 4, and 5. Each of the seven PIs has a unique subcellular and membrane domain distribution. In the enteric protozoan parasite Entamoeba histolytica, it has been previously shown that the PIs phosphatidylinositol 3-phosphate (PtdIns3P), PtdIns(4,5)P2, and PtdIns(3,4,5)P3 are localized to phagosomes/phagocytic cups, plasma membrane, and phagocytic cups, respectively. The localization of these PIs in E. histolytica is similar to that in mammalian cells, suggesting that PIs have orthologous functions in E. histolytica. In contrast, the conservation of the enzymes that metabolize PIs in this organism has not been well-documented. In this review, we summarized the full repertoire of the PI kinases and PI phosphatases found in E. histolytica via a genome-wide survey of the current genomic information. E. histolytica appears to have 10 PI kinases and 23 PI phosphatases. It has a panel of evolutionarily conserved enzymes that generate all the seven PI species. However, class II PI 3-kinases, type II PI 4-kinases, type III PI 5-phosphatases, and PI 4P-specific phosphatases are not present. Additionally, regulatory subunits of class I PI 3-kinases and type III PI 4-kinases have not been identified. Instead, homologs of class I PI 3-kinases and PTEN, a PI 3-phosphatase, exist as multiple isoforms, which likely reflects that elaborate signaling cascades mediated by PtdIns(3,4,5)P3 are present in this organism. There are several enzymes that have the nuclear localization signal: one phosphatidylinositol phosphate (PIP) kinase, two PI 3-phosphatases, and one PI 5-phosphatase; this suggests that PI metabolism also has conserved roles related to nuclear functions in E. histolytica, as it does in model organisms.
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Affiliation(s)
- Kumiko Nakada-Tsukui
- Department of Parasitology, National Institute of Infectious Diseases, Tokyo, Japan
| | - Natsuki Watanabe
- Department of Parasitology, National Institute of Infectious Diseases, Tokyo, Japan.,Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Japan
| | - Tomohiko Maehama
- Division of Molecular and Cellular Biology, Graduate School of Medicine, Kobe University, Kobe, Japan
| | - Tomoyoshi Nozaki
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
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17
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Vaz Dias F, Serrazina S, Vitorino M, Marchese D, Heilmann I, Godinho M, Rodrigues M, Malhó R. A role for diacylglycerol kinase 4 in signalling crosstalk during Arabidopsis pollen tube growth. THE NEW PHYTOLOGIST 2019; 222:1434-1446. [PMID: 30628082 DOI: 10.1111/nph.15674] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 12/28/2018] [Indexed: 05/29/2023]
Abstract
Diacylglycerol kinases (DGKs) play a major role in the production of phosphatidic acid (PtdOH) and were implicated in endomembrane trafficking and signalling cascades. In plants, the role of DGKs is less clear, as PtdOH seems to arise mostly from phospholipase D activity. Here, we investigated the function of the Arabidopsis gene encoding DGK4, which is highly expressed in pollen. In vitro, pollen tubes from homozygous dgk4 plants showed normal morphology, but reduced growth rate and altered stiffness and adhesion properties (revealed by atomic force microscopy). In vivo, dgk4 pollen was able to fertilize wild-type ovules, but self-pollination in dgk4 plants led to fewer seeds and shorter siliques. Phenotypic analysis revealed that the dgk4 mutation affects not only the male germ line but also the vegetative tissue. DGK4-green fluorescent protein fusion imaging revealed a cytosolic localization with a slightly higher signal in the subapical or apical region. dgk4 pollen tubes were found to exhibit perturbations in membrane recycling, and lipid analysis revealed a minor increase of PtdOH concomitant with decreased phosphatidylcholine, compared with wild-type. In vitro, DGK4 was found to exhibit kinase and guanylyl cyclase activity. Quantitative PCR data revealed downregulation of genes related to actin dynamics and phosphoinositide metabolism in mutant pollen, but upregulation of the DGK6 isoform. Altogether, these results are discussed considering a role of DGK4 in signalling cross-talk.
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Affiliation(s)
- Fernando Vaz Dias
- Faculdade de Ciências de Lisboa, BioISI, Universidade de Lisboa, 1749-016, Lisbon, Portugal
| | - Susana Serrazina
- Faculdade de Ciências de Lisboa, BioISI, Universidade de Lisboa, 1749-016, Lisbon, Portugal
| | - Miguel Vitorino
- Faculdade de Ciências de Lisboa, BioISI, Universidade de Lisboa, 1749-016, Lisbon, Portugal
| | - Dario Marchese
- Faculdade de Ciências de Lisboa, BioISI, Universidade de Lisboa, 1749-016, Lisbon, Portugal
| | - Ingo Heilmann
- Institute of Biochemistry and Biotechnology/Cellular Biochemistry, Martin-Luther-University Halle-Wittenberg, 06120, Halle (Saale), Germany
| | - Margarida Godinho
- Faculdade de Ciências de Lisboa, BioISI, Universidade de Lisboa, 1749-016, Lisbon, Portugal
| | - Mário Rodrigues
- Faculdade de Ciências de Lisboa, BioISI, Universidade de Lisboa, 1749-016, Lisbon, Portugal
| | - Rui Malhó
- Faculdade de Ciências de Lisboa, BioISI, Universidade de Lisboa, 1749-016, Lisbon, Portugal
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18
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Caillaud MC. Anionic Lipids: A Pipeline Connecting Key Players of Plant Cell Division. FRONTIERS IN PLANT SCIENCE 2019; 10:419. [PMID: 31110508 PMCID: PMC6499208 DOI: 10.3389/fpls.2019.00419] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Accepted: 03/19/2019] [Indexed: 05/23/2023]
Abstract
How cells position their division plane is a critical component of cell division. Indeed, it defines whether the two daughter cells divide symmetrically (with equal volumes) or not, and as such is critical for cell differentiation and lineage specification across eukaryotes. However, oriented cell divisions are of special significance for organisms with cell walls, such as plants, because their cells are embedded and cannot relocate. Correctly positioning the division plane is therefore of prevailing importance in plants, as it controls not only the occurrence of asymmetric cell division, but also tissue morphogenesis and organ integrity. While cytokinesis is executed in radically different manners in animals and plants, they both rely on the dynamic interplay between the cytoskeleton and membrane trafficking to precisely deliver molecular components to the future site of cell division. Recent research has shown that strict regulation of the levels and distribution of anionic lipids, which are minor components of the cell membrane's lipids, is required for successful cytokinesis in non-plant organisms. This review focused on the recent evidence pointing to whether such signaling lipids have roles in plant cell division.
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Affiliation(s)
- Marie-Cécile Caillaud
- Laboratoire Reproduction et Développement des Plantes, Université de Lyon, ENS de Lyon, UCB Lyon 1, CNRS, INRA, Lyon, France
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19
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Shin YJ, Sa JK, Lee Y, Kim D, Chang N, Cho HJ, Son M, Oh MYT, Shin K, Lee JK, Park J, Jo YK, Kim M, Paddison PJ, Tergaonkar V, Lee J, Nam DH. PIP4K2A as a negative regulator of PI3K in PTEN -deficient glioblastoma. J Exp Med 2019; 216:1120-1134. [PMID: 30898893 PMCID: PMC6504209 DOI: 10.1084/jem.20172170] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 08/20/2018] [Accepted: 02/27/2019] [Indexed: 01/01/2023] Open
Abstract
Glioblastoma (GBM) is the most malignant brain tumor with profound genomic alterations. Tumor suppressor genes regulate multiple signaling networks that restrict cellular proliferation and present barriers to malignant transformation. While bona fide tumor suppressors such as PTEN and TP53 often undergo inactivation due to mutations, there are several genes for which genomic deletion is the primary route for tumor progression. To functionally identify putative tumor suppressors in GBM, we employed in vivo RNAi screening using patient-derived xenograft models. Here, we identified PIP4K2A, whose functional role and clinical relevance remain unexplored in GBM. We discovered that PIP4K2A negatively regulates phosphoinositide 3-kinase (PI3K) signaling via p85/p110 component degradation in PTEN-deficient GBMs and specifically targets p85 for proteasome-mediated degradation. Overexpression of PIP4K2A suppressed cellular and clonogenic growth in vitro and impeded tumor growth in vivo. Our results unravel a novel tumor-suppressive role of PIP4K2A for the first time and support the feasibility of combining oncogenomics with in vivo RNAi screen.
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Affiliation(s)
- Yong Jae Shin
- Institute for Refractory Cancer Research, Samsung Medical Center, Seoul, Korea.,Research Institute for Future Medicine, Samsung Medical Center, Seoul, Korea.,Department of Neurosurgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Jason K Sa
- Institute for Refractory Cancer Research, Samsung Medical Center, Seoul, Korea.,Research Institute for Future Medicine, Samsung Medical Center, Seoul, Korea
| | - Yeri Lee
- Institute for Refractory Cancer Research, Samsung Medical Center, Seoul, Korea.,Research Institute for Future Medicine, Samsung Medical Center, Seoul, Korea
| | - Donggeon Kim
- Institute for Refractory Cancer Research, Samsung Medical Center, Seoul, Korea.,Research Institute for Future Medicine, Samsung Medical Center, Seoul, Korea
| | | | - Hee Jin Cho
- Institute for Refractory Cancer Research, Samsung Medical Center, Seoul, Korea.,Research Institute for Future Medicine, Samsung Medical Center, Seoul, Korea
| | - Miseol Son
- Institute for Refractory Cancer Research, Samsung Medical Center, Seoul, Korea.,Division of Cancer Cell Signaling, Institute of Molecular and Cell Biology, Singapore
| | - Michael Y T Oh
- Institute for Cancer Genetics, Columbia University Medical Center, New York, NY
| | - Kayoung Shin
- Institute for Refractory Cancer Research, Samsung Medical Center, Seoul, Korea.,Department of Health Sciences and Technology, Samsung Advanced Institute for Health Science and Technology, Sungkyunkwan University, Seoul, Korea
| | - Jin-Ku Lee
- Institute for Refractory Cancer Research, Samsung Medical Center, Seoul, Korea.,Research Institute for Future Medicine, Samsung Medical Center, Seoul, Korea
| | - Jiwon Park
- Institute for Refractory Cancer Research, Samsung Medical Center, Seoul, Korea
| | - Yoon Kyung Jo
- Institute for Refractory Cancer Research, Samsung Medical Center, Seoul, Korea.,Research Institute for Future Medicine, Samsung Medical Center, Seoul, Korea
| | - Misuk Kim
- Institute for Refractory Cancer Research, Samsung Medical Center, Seoul, Korea.,Research Institute for Future Medicine, Samsung Medical Center, Seoul, Korea
| | - Patrick J Paddison
- Human Biology Division, Fred Hutchinson Cancer Research Center, Seattle, WA
| | - Vinay Tergaonkar
- Division of Cancer Cell Signaling, Institute of Molecular and Cell Biology, Singapore.,Department of Pathology, National University of Singapore, Singapore
| | - Jeongwu Lee
- Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH
| | - Do-Hyun Nam
- Institute for Refractory Cancer Research, Samsung Medical Center, Seoul, Korea .,Research Institute for Future Medicine, Samsung Medical Center, Seoul, Korea.,Department of Neurosurgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.,Department of Health Sciences and Technology, Samsung Advanced Institute for Health Science and Technology, Sungkyunkwan University, Seoul, Korea
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20
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Covino R, Hummer G, Ernst R. Integrated Functions of Membrane Property Sensors and a Hidden Side of the Unfolded Protein Response. Mol Cell 2019; 71:458-467. [PMID: 30075144 DOI: 10.1016/j.molcel.2018.07.019] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Revised: 07/09/2018] [Accepted: 07/17/2018] [Indexed: 12/26/2022]
Abstract
Eukaryotic cells face the challenge of maintaining the complex composition of several coexisting organelles. The molecular mechanisms underlying the homeostasis of subcellular membranes and their adaptation during stress are only now starting to emerge. Here, we discuss three membrane property sensors of the endoplasmic reticulum (ER), namely OPI1, MGA2, and IRE1, each controlling a large cellular program impacting the lipid metabolic network. OPI1 coordinates the production of membrane and storage lipids, MGA2 regulates the production of unsaturated fatty acids required for membrane biogenesis, and IRE1 controls the unfolded protein response (UPR) to adjust ER size, protein folding, and the secretory capacity of the cell. Although these proteins use remarkably distinct sensing mechanisms, they are functionally connected via the ER membrane and cooperate to maintain membrane homeostasis. As a rationalization of the recently described mechanism of UPR activation by lipid bilayer stress, we propose that IRE1 can sense the protein-to-lipid ratio in the ER membrane to ensure a balanced production of membrane proteins and lipids.
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Affiliation(s)
- Roberto Covino
- Department of Theoretical Biophysics, Max Planck Institute of Biophysics, Max-von-Laue-Strasse 3, 60438 Frankfurt am Main, Germany
| | - Gerhard Hummer
- Department of Theoretical Biophysics, Max Planck Institute of Biophysics, Max-von-Laue-Strasse 3, 60438 Frankfurt am Main, Germany; Institute of Biophysics, Goethe University, 60438 Frankfurt am Main, Germany
| | - Robert Ernst
- Department of Medical Biochemistry and Molecular Biology, Saarland University, Kirrberger Str. 100, Gebäude 61.4, 66421 Homburg, Germany.
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21
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Yuan T, Li J, Zhao WG, Sun W, Liu SN, Liu Q, Fu Y, Shen ZF. Effects of metformin on metabolism of white and brown adipose tissue in obese C57BL/6J mice. Diabetol Metab Syndr 2019; 11:96. [PMID: 31788033 PMCID: PMC6880501 DOI: 10.1186/s13098-019-0490-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Accepted: 10/30/2019] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND To investigate effects of metformin on the regulation of proteins of white adipose tissue (WAT) and brown adipose tissue (BAT) in obesity and explore the underlying mechanisms on energy metabolism. METHODS C57BL/6J mice were fed with normal diet (ND, n = 6) or high-fat diet (HFD, n = 12) for 22 weeks. HFD-induced obese mice were treated with metformin (MET, n = 6). After treatment for 8 weeks, oral glucose tolerance test (OGTT) and hyperinsulinemic-euglycemic clamp were performed to evaluate the improvement of glucose tolerance and insulin sensitivity. Protein expressions of WAT and BAT in mice among ND, HFD, and MET group were identified and quantified with isobaric tag for relative and absolute quantification (iTRAQ) coupled with 2D LC-MS/MS. The results were analyzed by MASCOT, Scaffold and IPA. RESULTS The glucose infusion rate in MET group was increased significantly compared with HFD group. We identified 4388 and 3486 proteins in WAT and BAT, respectively. As compared MET to HFD, differential expressed proteins in WAT and BAT were mainly assigned to the pathways of EIF2 signaling and mitochondrial dysfunction, respectively. In the pathways, CPT1a in WAT, CPT1b and CPT2 in BAT were down-regulated by metformin significantly. CONCLUSIONS Metformin improved the body weight and insulin sensitivity of obese mice. Meanwhile, metformin might ameliorate endoplasmic reticulum stress in WAT, and affect fatty acid metabolism in WAT and BAT. CPT1 might be a potential target of metformin in WAT and BAT.
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Affiliation(s)
- Tao Yuan
- Department of Endocrinology, Key Laboratory of Endocrinology of The National Health and Family Planning Commission, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - Juan Li
- Department of Endocrinology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Wei-Gang Zhao
- Department of Endocrinology, Key Laboratory of Endocrinology of The National Health and Family Planning Commission, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - Wei Sun
- Core Facility of Instrument, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences/School of Basic Medicine, Peking Union Medical College, Beijing, China
| | - Shuai-Nan Liu
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Diabetes Research Center of Chinese Academy of Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Quan Liu
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Diabetes Research Center of Chinese Academy of Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Yong Fu
- Department of Endocrinology, Key Laboratory of Endocrinology of The National Health and Family Planning Commission, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - Zhu-Fang Shen
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Diabetes Research Center of Chinese Academy of Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
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22
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Bhakt P, Shivarathri R, Choudhary DK, Borah S, Kaur R. Fluconazole-induced actin cytoskeleton remodeling requires phosphatidylinositol 3-phosphate 5-kinase in the pathogenic yeast Candida glabrata. Mol Microbiol 2018; 110:425-443. [PMID: 30137648 PMCID: PMC6221164 DOI: 10.1111/mmi.14110] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Revised: 08/09/2018] [Accepted: 08/10/2018] [Indexed: 11/29/2022]
Abstract
Known azole antifungal resistance mechanisms include mitochondrial dysfunction and overexpression of the sterol biosynthetic target enzyme and multidrug efflux pumps. Here, we identify, through a genetic screen, the vacuolar membrane‐resident phosphatidylinositol 3‐phosphate 5‐kinase (CgFab1) to be a novel determinant of azole tolerance. We demonstrate for the first time that fluconazole promotes actin cytoskeleton reorganization in the emerging, inherently less azole‐susceptible fungal pathogen Candida glabrata, and genetic or chemical perturbation of actin structures results in intracellular sterol accumulation and azole susceptibility. Further, CgFAB1 disruption impaired vacuole homeostasis and actin organization, and the F‐actin‐stabilizing compound jasplakinolide rescued azole toxicity in cytoskeleton defective‐mutants including the Cgfab1Δ mutant. In vitro assays revealed that the actin depolymerization factor CgCof1 binds to multiple lipids including phosphatidylinositol 3,5‐bisphosphate. Consistently, CgCof1 distribution along with the actin filament‐capping protein CgCap2 was altered upon both CgFAB1 disruption and fluconazole exposure. Altogether, these data implicate CgFab1 in azole tolerance through actin network remodeling. Finally, we also show that actin polymerization inhibition rendered fluconazole fully and partially fungicidal in azole‐susceptible and azole‐resistant C. glabrata clinical isolates, respectively, thereby, underscoring the role of fluconazole‐effectuated actin remodeling in azole resistance.
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Affiliation(s)
- Priyanka Bhakt
- Laboratory of Fungal Pathogenesis, Centre for DNA Fingerprinting and Diagnostics, Hyderabad, Telangana, India.,Graduate Studies, Manipal Academy of Higher Education, Manipal, Karnataka, India
| | - Raju Shivarathri
- Laboratory of Fungal Pathogenesis, Centre for DNA Fingerprinting and Diagnostics, Hyderabad, Telangana, India
| | - Deepak Kumar Choudhary
- Laboratory of Fungal Pathogenesis, Centre for DNA Fingerprinting and Diagnostics, Hyderabad, Telangana, India
| | - Sapan Borah
- Laboratory of Fungal Pathogenesis, Centre for DNA Fingerprinting and Diagnostics, Hyderabad, Telangana, India
| | - Rupinder Kaur
- Laboratory of Fungal Pathogenesis, Centre for DNA Fingerprinting and Diagnostics, Hyderabad, Telangana, India
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23
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Batool S, Joseph TP, Hussain M, Vuai MS, Khinsar KH, Din SRU, Padhiar AA, Zhong M, Ning A, Zhang W, Cao J, Huang M. LP1 from Lentinula edodes C 91-3 Induces Autophagy, Apoptosis and Reduces Metastasis in Human Gastric Cancer Cell Line SGC-7901. Int J Mol Sci 2018; 19:E2986. [PMID: 30274346 PMCID: PMC6213425 DOI: 10.3390/ijms19102986] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 09/24/2018] [Accepted: 09/27/2018] [Indexed: 12/30/2022] Open
Abstract
Present study aimed to elucidate the anticancer effect and the possible molecular mechanism underlying the action of Latcripin 1 (LP1), from the mushroom Lentinula edodes strain C91-3 against gastric cancer cell lines SGC-7901 and BGC-823. Cell viability was measured by Cell Counting Kit-8 (CCK-8); morphological changes were observed by phase contrast microscope; autophagy was determined by transmission electron microscope and fluorescence microscope. Apoptosis and cell cycle were assessed by flow cytometer; wound-healing, transwell migration and invasion assays were performed to investigate the effect of LP1 on gastric cancer cell's migration and invasion. Herein, we found that LP1 resulted in the induction of autophagy by the formation of autophagosomes and conversion of light chain 3 (LC3I into LC3II. LP1 up-regulated the expression level of autophagy-related gene (Atg7, Atg5, Atg12, Atg14) and Beclin1; increased and decreased the expression level of pro-apoptotic (Bax) and anti-apoptotic (Bcl-2) proteins respectively, along with the activation of Caspase-3. At lower-doses, LP1 have shown to arrest cells in the S phase of the cell cycle and decreased the expression level of matrix metalloproteinase MMP-2 and MMP-9. In addition, it has also been shown to regulate the phosphorylation of one of the most hampered gastric cancer pathway, that is, protein kinase B/mammalian target of rapamycin (Akt/mTOR) channel and resulted in cell death. These findings suggested LP1 as a potential natural anti-cancer agent, for exploring the gastric cancer therapies and as a contender for further in vitro and in vivo investigations.
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Affiliation(s)
- Samana Batool
- Department of Microbiology, College of Basic Medical Sciences, Dalian Medical University, Dalian 116044, China.
| | - Thomson Patrick Joseph
- Department of Microbiology, College of Basic Medical Sciences, Dalian Medical University, Dalian 116044, China.
| | - Mushraf Hussain
- State Key Laboratory of Fine Chemicals, School of Chemical Engineering, Dalian University of Technology, E-208 West Campus, Dalian 116024, China.
| | - Miza S Vuai
- Department of Microbiology, College of Basic Medical Sciences, Dalian Medical University, Dalian 116044, China.
| | - Kavish H Khinsar
- Department of Microbiology, College of Basic Medical Sciences, Dalian Medical University, Dalian 116044, China.
| | - Syed Riaz Ud Din
- Department of Microbiology, College of Basic Medical Sciences, Dalian Medical University, Dalian 116044, China.
| | - Arshad Ahmed Padhiar
- Department of Microbiology, College of Basic Medical Sciences, Dalian Medical University, Dalian 116044, China.
| | - Mintao Zhong
- Department of Microbiology, College of Basic Medical Sciences, Dalian Medical University, Dalian 116044, China.
| | - Anhong Ning
- Department of Microbiology, College of Basic Medical Sciences, Dalian Medical University, Dalian 116044, China.
| | - Wei Zhang
- Department of Microbiology, College of Basic Medical Sciences, Dalian Medical University, Dalian 116044, China.
| | - Jing Cao
- Department of Microbiology, College of Basic Medical Sciences, Dalian Medical University, Dalian 116044, China.
| | - Min Huang
- Department of Microbiology, College of Basic Medical Sciences, Dalian Medical University, Dalian 116044, China.
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24
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Membrane-Associated Proteins in Giardia lamblia. Genes (Basel) 2018; 9:genes9080404. [PMID: 30103435 PMCID: PMC6115752 DOI: 10.3390/genes9080404] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Revised: 08/03/2018] [Accepted: 08/07/2018] [Indexed: 01/01/2023] Open
Abstract
The manner in which membrane-associated proteins interact with the membrane defines their subcellular fate and function. This interaction relies on the characteristics of the proteins, their journey after synthesis, and their interaction with other proteins or enzymes. Understanding these properties may help to define the function of a protein and also the role of an organelle. In the case of microorganisms like protozoa parasites, it may help to understand singular features that will eventually lead to the design of parasite-specific drugs. The protozoa parasite Giardia lamblia is an example of a widespread parasite that has been infecting humans and animals from ancestral times, adjusting itself to the changes of the environment inside and outside the host. Several membrane-associated proteins have been posted in the genome database GiardiaDB, although only a few of them have been characterized. This review discusses the data regarding membrane-associated proteins in relationship with lipids and specific organelles and their implication in the discovery of anti-giardial therapies.
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25
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Hofbauer HF, Gecht M, Fischer SC, Seybert A, Frangakis AS, Stelzer EHK, Covino R, Hummer G, Ernst R. The molecular recognition of phosphatidic acid by an amphipathic helix in Opi1. J Cell Biol 2018; 217:3109-3126. [PMID: 29941475 PMCID: PMC6122994 DOI: 10.1083/jcb.201802027] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Revised: 05/28/2018] [Accepted: 06/18/2018] [Indexed: 01/09/2023] Open
Abstract
Phosphatidic acid (PA) lipids have a dual role as building blocks for membrane biogenesis and as active signaling molecules. This study establishes the molecular details of selective PA recognition by the transcriptional regulator Opi1 from baker’s yeast. A key event in cellular physiology is the decision between membrane biogenesis and fat storage. Phosphatidic acid (PA) is an important intermediate at the branch point of these pathways and is continuously monitored by the transcriptional repressor Opi1 to orchestrate lipid metabolism. In this study, we report on the mechanism of membrane recognition by Opi1 and identify an amphipathic helix (AH) for selective binding of PA over phosphatidylserine (PS). The insertion of the AH into the membrane core renders Opi1 sensitive to the lipid acyl chain composition and provides a means to adjust membrane biogenesis. By rational design of the AH, we tune the membrane-binding properties of Opi1 and control its responsiveness in vivo. Using extensive molecular dynamics simulations, we identify two PA-selective three-finger grips that tightly bind the PA phosphate headgroup while interacting less intimately with PS. This work establishes lipid headgroup selectivity as a new feature in the family of AH-containing membrane property sensors.
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Affiliation(s)
- Harald F Hofbauer
- Buchmann Institute for Molecular Life Sciences, Goethe University Frankfurt, Frankfurt, Germany .,Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Frankfurt, Germany.,Institute of Medical Biochemistry and Molecular Biology, School of Medicine, University of Saarland, Homburg, Germany
| | - Michael Gecht
- Buchmann Institute for Molecular Life Sciences, Goethe University Frankfurt, Frankfurt, Germany.,Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Frankfurt, Germany.,Department of Theoretical Biophysics, Max Planck Institute of Biophysics, Frankfurt, Germany
| | - Sabine C Fischer
- Buchmann Institute for Molecular Life Sciences, Goethe University Frankfurt, Frankfurt, Germany.,Physical Biology, Interdisciplinary Center for Neuroscience, Goethe University Frankfurt, Frankfurt, Germany
| | - Anja Seybert
- Buchmann Institute for Molecular Life Sciences, Goethe University Frankfurt, Frankfurt, Germany
| | - Achilleas S Frangakis
- Buchmann Institute for Molecular Life Sciences, Goethe University Frankfurt, Frankfurt, Germany
| | - Ernst H K Stelzer
- Buchmann Institute for Molecular Life Sciences, Goethe University Frankfurt, Frankfurt, Germany.,Physical Biology, Interdisciplinary Center for Neuroscience, Goethe University Frankfurt, Frankfurt, Germany
| | - Roberto Covino
- Department of Theoretical Biophysics, Max Planck Institute of Biophysics, Frankfurt, Germany
| | - Gerhard Hummer
- Department of Theoretical Biophysics, Max Planck Institute of Biophysics, Frankfurt, Germany.,Institute for Biophysics, Goethe University Frankfurt, Frankfurt, Germany
| | - Robert Ernst
- Institute of Medical Biochemistry and Molecular Biology, School of Medicine, University of Saarland, Homburg, Germany
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26
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Nanoscale domain formation of phosphatidylinositol 4-phosphate in the plasma and vacuolar membranes of living yeast cells. Eur J Cell Biol 2018; 97:269-278. [PMID: 29609807 DOI: 10.1016/j.ejcb.2018.03.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Revised: 02/27/2018] [Accepted: 03/20/2018] [Indexed: 12/31/2022] Open
Abstract
In budding yeast Saccharomyces cerevisiae, PtdIns(4)P serves as an essential signalling molecule in the Golgi complex, endosomal system, and plasma membrane, where it is involved in the control of multiple cellular functions via direct interactions with PtdIns(4)P-binding proteins. To analyse the distribution of PtdIns(4)P in yeast cells at a nanoscale level, we employed an electron microscopy technique that specifically labels PtdIns(4)P on the freeze-fracture replica of the yeast membrane. This method minimizes the possibility of artificial perturbation, because molecules in the membrane are physically immobilised in situ. We observed that PtdIns(4)P is localised on the cytoplasmic leaflet, but not the exoplasmic leaflet, of the plasma membrane, Golgi body, vacuole, and vesicular structure membranes. PtdIns(4)P labelling was not observed in the membrane of the endoplasmic reticulum, and in the outer and inner membranes of the nuclear envelope or mitochondria. PtdIns(4)P forms clusters of <100 nm in diameter in the plasma membrane and vacuolar membrane according to point pattern analysis of immunogold labelling. There are three kinds of compartments in the cytoplasmic leaflet of the plasma membrane. In the present study, we showed that PtdIns(4)P is specifically localised in the flat undifferentiated plasma membrane compartment. In the vacuolar membrane, PtdIns(4)P was concentrated in intramembrane particle (IMP)-deficient raft-like domains, which are tightly bound to lipid droplets, but not surrounding IMP-rich non-raft domains in geometrical IMP-distributed patterns in the stationary phase. This is the first report showing microdomain formations of PtdIns(4)P in the plasma membrane and vacuolar membrane of budding yeast cells at a nanoscale level, which will illuminate the functionality of PtdIns(4)P in each membrane.
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27
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PIP3-binding proteins promote age-dependent protein aggregation and limit survival in C. elegans. Oncotarget 2018; 7:48870-48886. [PMID: 27429199 PMCID: PMC5226477 DOI: 10.18632/oncotarget.10549] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2016] [Accepted: 06/20/2016] [Indexed: 12/17/2022] Open
Abstract
Class-I phosphatidylinositol 3-kinase (PI3KI) converts phosphatidylinositol 4,5-bisphosphate (PIP2) to phosphatidylinositol 3,4,5-triphosphate (PIP3). PIP3 comprises two fatty-acid chains that embed in lipid-bilayer membranes, joined by glycerol to inositol triphosphate. Proteins with domains that specifically bind that head-group (e.g. pleckstrin-homology [PH] domains) are thus tethered to the inner plasma-membrane surface where they have an enhanced likelihood of interaction with other PIP3-bound proteins, in particular other components of their signaling pathways. Null alleles of the C. elegans age-1 gene, encoding the catalytic subunit of PI3KI, lack any detectable class-I PI3K activity and so cannot form PIP3. These mutant worms survive almost 10-fold longer than the longest-lived normal control, and are highly resistant to a variety of stresses including oxidative and electrophilic challenges. Traits associated with age-1 mutation are widely believed to be mediated through AKT-1, which requires PIP3 for both tethering and activation. Active AKT complex phosphorylates and thereby inactivates the DAF-16/FOXO transcription factor. However, extensive evidence indicates that pleiotropic effects of age-1-null mutations, including extreme longevity, cannot be explained by insulin like-receptor/AKT/FOXO signaling alone, suggesting involvement of other PIP3-binding proteins. We used ligand-affinity capture to identify membrane-bound proteins downstream of PI3KI that preferentially bind PIP3. Computer modeling supports a subset of candidate proteins predicted to directly bind PIP3 in preference to PIP2, and functional testing by RNAi knockdown confirmed candidates that partially mediate the stress-survival, aggregation-reducing and longevity benefits of PI3KI disruption. PIP3-specific candidate sets are highly enriched for proteins previously reported to affect translation, stress responses, lifespan, proteostasis, and lipid transport.
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28
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Gottschling DE, Nyström T. The Upsides and Downsides of Organelle Interconnectivity. Cell 2017; 169:24-34. [PMID: 28340346 DOI: 10.1016/j.cell.2017.02.030] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Revised: 02/13/2017] [Accepted: 02/21/2017] [Indexed: 12/31/2022]
Abstract
Interconnectivity and feedback control are hallmarks of biological systems. This includes communication between organelles, which allows them to function and adapt to changing cellular environments. While the specific mechanisms for all communications remain opaque, unraveling the wiring of organelle networks is critical to understand how biological systems are built and why they might collapse, as occurs in aging. A comprehensive understanding of all the routes involved in inter-organelle communication is still lacking, but important themes are beginning to emerge, primarily in budding yeast. These routes are reviewed here in the context of sub-system proteostasis and complex adaptive systems theory.
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Affiliation(s)
| | - Thomas Nyström
- Institute for Biomedicine, Sahlgrenska Academy, University of Gothenburg, 405 30 Gothenburg, Sweden.
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29
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Dalton LE, Bean BDM, Davey M, Conibear E. Quantitative high-content imaging identifies novel regulators of Neo1 trafficking at endosomes. Mol Biol Cell 2017; 28:1539-1550. [PMID: 28404745 PMCID: PMC5449152 DOI: 10.1091/mbc.e16-11-0772] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Revised: 04/05/2017] [Accepted: 04/06/2017] [Indexed: 12/21/2022] Open
Abstract
P4-ATPases are a family of putative phospholipid flippases that regulate lipid membrane asymmetry, which is important for vesicle formation. Two yeast flippases, Drs2 and Neo1, have nonredundant functions in the recycling of the synaptobrevin-like v-SNARE Snc1 from early endosomes. Drs2 activity is needed to form vesicles and regulate its own trafficking, suggesting that flippase activity and localization are linked. However, the role of Neo1 in endosomal recycling is not well characterized. To identify novel regulators of Neo1 trafficking and activity at endosomes, we first identified mutants with impaired recycling of a Snc1-based reporter and subsequently used high-content microscopy to classify these mutants based on the localization of Neo1 or its binding partners, Mon2 and Dop1. This analysis identified a role for Arl1 in stabilizing the Mon2/Dop1 complex and uncovered a new function for Vps13 in early endosome recycling and Neo1 localization. We further showed that the cargo-selective sorting nexin Snx3 is required for Neo1 trafficking and identified an Snx3 sorting motif in the Neo1 N-terminus. Of importance, the Snx3-dependent sorting of Neo1 was required for the correct sorting of another Snx3 cargo protein, suggesting that the incorporation of Neo1 into recycling tubules may influence their formation.
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Affiliation(s)
- Lauren E Dalton
- Centre for Molecular Medicine and Therapeutics, BC Children's Hospital, University of British Columbia, Vancouver, BC V5Z 4H4, Canada
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Björn D M Bean
- Centre for Molecular Medicine and Therapeutics, BC Children's Hospital, University of British Columbia, Vancouver, BC V5Z 4H4, Canada
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Michael Davey
- Centre for Molecular Medicine and Therapeutics, BC Children's Hospital, University of British Columbia, Vancouver, BC V5Z 4H4, Canada
| | - Elizabeth Conibear
- Centre for Molecular Medicine and Therapeutics, BC Children's Hospital, University of British Columbia, Vancouver, BC V5Z 4H4, Canada
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
- Department of Medical Genetics, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
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30
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Jana A, Sinha A, Sarkar S. Phosphoinositide binding profiles of the PX domains of Giardia lamblia. Parasitol Int 2017; 66:606-614. [PMID: 28456494 DOI: 10.1016/j.parint.2017.04.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Revised: 04/13/2017] [Accepted: 04/23/2017] [Indexed: 10/19/2022]
Abstract
The membrane trafficking machinery that functions at the endomembrane system of Giardia lamblia appears to be significantly different from that present in most model eukaryotes. This machinery is important for encystation as cyst wall material is trafficked to the cell surface via encystation-specific vesicles. Since proteins containing the phosphoinositide-binding PX domains are known regulators of vesicular trafficking, BLAST search was used to identify the PX domains of G. lamblia. Six putative PX domain-containing ORFs were identified. Some of the encoded PX domains contained non-canonical amino acid residues in the highly conserved ligand binding pocket. In vitro and in vivo binding studies indicate that these domains have the ability to bind to diverse phosphoinositides. Also, coincidence detection is likely to play a significant role in ligand binding in vivo since domains that bind to the same lipid in vitro, exhibit differences in subcellular localization. Analyses of the expression of these six genes in trophozoites, encysting trophozoites and cysts showed that while the expression of four of the genes were downregulated in cysts, the other two were upregulated. The variation in ligand preference of the individual PX domains and the differential expression of most of the PX-domain encoding genes indicate that these PX domain-containing proteins are likely to perform diverse cellular functions.
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Affiliation(s)
- Ananya Jana
- Department of Biochemistry, Bose Institute, P1/12 CIT Scheme VII M, Kolkata 700054, West Bengal, India
| | - Abhishek Sinha
- Department of Biochemistry, Bose Institute, P1/12 CIT Scheme VII M, Kolkata 700054, West Bengal, India
| | - Srimonti Sarkar
- Department of Biochemistry, Bose Institute, P1/12 CIT Scheme VII M, Kolkata 700054, West Bengal, India.
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31
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Wiessner M, Roos A, Munn CJ, Viswanathan R, Whyte T, Cox D, Schoser B, Sewry C, Roper H, Phadke R, Marini Bettolo C, Barresi R, Charlton R, Bönnemann CG, Abath Neto O, Reed UC, Zanoteli E, Araújo Martins Moreno C, Ertl-Wagner B, Stucka R, De Goede C, Borges da Silva T, Hathazi D, Dell’Aica M, Zahedi RP, Thiele S, Müller J, Kingston H, Müller S, Curtis E, Walter MC, Strom TM, Straub V, Bushby K, Muntoni F, Swan LE, Lochmüller H, Senderek J. Mutations in INPP5K, Encoding a Phosphoinositide 5-Phosphatase, Cause Congenital Muscular Dystrophy with Cataracts and Mild Cognitive Impairment. Am J Hum Genet 2017; 100:523-536. [PMID: 28190456 PMCID: PMC5339217 DOI: 10.1016/j.ajhg.2017.01.024] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Accepted: 01/12/2017] [Indexed: 12/26/2022] Open
Abstract
Phosphoinositides are small phospholipids that control diverse cellular downstream signaling events. Their spatial and temporal availability is tightly regulated by a set of specific lipid kinases and phosphatases. Congenital muscular dystrophies are hereditary disorders characterized by hypotonia and weakness from birth with variable eye and central nervous system involvement. In individuals exhibiting congenital muscular dystrophy, early-onset cataracts, and mild intellectual disability but normal cranial magnetic resonance imaging, we identified bi-allelic mutations in INPP5K, encoding inositol polyphosphate-5-phosphatase K. Mutations impaired phosphatase activity toward the phosphoinositide phosphatidylinositol (4,5)-bisphosphate or altered the subcellular localization of INPP5K. Downregulation of INPP5K orthologs in zebrafish embryos disrupted muscle fiber morphology and resulted in abnormal eye development. These data link congenital muscular dystrophies to defective phosphoinositide 5-phosphatase activity that is becoming increasingly recognized for its role in mediating pivotal cellular mechanisms contributing to disease.
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32
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Lucas C, Ferreira C, Cazzanelli G, Franco-Duarte R, Tulha J, Roelink H, Conway SJ. Yeast Gup1(2) Proteins Are Homologues of the Hedgehog Morphogens Acyltransferases HHAT(L): Facts and Implications. J Dev Biol 2016; 4:E33. [PMID: 29615596 PMCID: PMC5831804 DOI: 10.3390/jdb4040033] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Revised: 10/25/2016] [Accepted: 10/27/2016] [Indexed: 12/16/2022] Open
Abstract
In multiple tissues, the Hedgehog secreted morphogen activates in the receiving cells a pathway involved in cell fate, proliferation and differentiation in the receiving cells. This pathway is particularly important during embryogenesis. The protein HHAT (Hedgehog O-acyltransferase) modifies Hh morphogens prior to their secretion, while HHATL (Hh O-acyltransferase-like) negatively regulates the pathway. HHAT and HHATL are homologous to Saccharomyces cerevisiae Gup2 and Gup1, respectively. In yeast, Gup1 is associated with a high number and diversity of biological functions, namely polarity establishment, secretory/endocytic pathway functionality, vacuole morphology and wall and membrane composition, structure and maintenance. Phenotypes underlying death, morphogenesis and differentiation are also included. Paracrine signalling, like the one promoted by the Hh pathway, has not been shown to occur in microbial communities, despite the fact that large aggregates of cells like biofilms or colonies behave as proto-tissues. Instead, these have been suggested to sense the population density through the secretion of quorum-sensing chemicals. This review focuses on Gup1/HHATL and Gup2/HHAT proteins. We review the functions and physiology associated with these proteins in yeasts and higher eukaryotes. We suggest standardisation of the presently chaotic Gup-related nomenclature, which includes KIAA117, c3orf3, RASP, Skinny, Sightless and Central Missing, in order to avoid the disclosure of otherwise unnoticed information.
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Affiliation(s)
- Cândida Lucas
- CBMA—Centre of Molecular and Environmental Biology, University of Minho, Campus de Gualtar, 4710-054 Braga, Portugal; (G.C.); (R.F.-D.); (J.T.)
| | - Célia Ferreira
- CBMA—Centre of Molecular and Environmental Biology, University of Minho, Campus de Gualtar, 4710-054 Braga, Portugal; (G.C.); (R.F.-D.); (J.T.)
- School of Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK;
| | - Giulia Cazzanelli
- CBMA—Centre of Molecular and Environmental Biology, University of Minho, Campus de Gualtar, 4710-054 Braga, Portugal; (G.C.); (R.F.-D.); (J.T.)
| | - Ricardo Franco-Duarte
- CBMA—Centre of Molecular and Environmental Biology, University of Minho, Campus de Gualtar, 4710-054 Braga, Portugal; (G.C.); (R.F.-D.); (J.T.)
| | - Joana Tulha
- CBMA—Centre of Molecular and Environmental Biology, University of Minho, Campus de Gualtar, 4710-054 Braga, Portugal; (G.C.); (R.F.-D.); (J.T.)
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33
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New Insight Into the Roles of Membrane Microdomains in Physiological Activities of Fungal Cells. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2016; 325:119-80. [PMID: 27241220 DOI: 10.1016/bs.ircmb.2016.02.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The organization of biological membranes into structurally and functionally distinct lateral microdomains is generally accepted. From bacteria to mammals, laterally compartmentalized membranes seem to be a vital attribute of life. The crucial fraction of our current knowledge about the membrane microdomains has been gained from studies on fungi. In this review we summarize the evidence of the microdomain organization of membranes from fungal cells, with accent on their enormous diversity in composition, temporal dynamics, modes of formation, and recognized engagement in the cell physiology. A special emphasis is laid on the fact that in addition to their other biological functions, membrane microdomains also mediate the communication among different membranes within a eukaryotic cell and coordinate their functions. Involvement of fungal membrane microdomains in stress sensing, regulation of lipid homeostasis, and cell differentiation is discussed more in detail.
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Phosphatidylinositol phosphate kinase PIPKIγ and phosphatase INPP5E coordinate initiation of ciliogenesis. Nat Commun 2016; 7:10777. [PMID: 26916822 PMCID: PMC4773430 DOI: 10.1038/ncomms10777] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Accepted: 01/19/2016] [Indexed: 02/08/2023] Open
Abstract
Defective primary cilia are causative to a wide spectrum of human genetic disorders, termed ciliopathies. Although the regulation of ciliogenesis is intensively studied, how it is initiated remains unclear. Here we show that type Iγ phosphatidylinositol 4-phosphate (PtdIns(4)P) 5-kinase (PIPKIγ) and inositol polyphosphate-5-phosphatase E (INPP5E), a Joubert syndrome protein, localize to the centrosome and coordinate the initiation of ciliogenesis. PIPKIγ counteracts INPP5E in regulating tau-tubulin kinase-2 (TTBK2) recruitment to the basal body, which promotes the removal of microtubule capping protein CP110 and the subsequent axoneme elongation. Interestingly, INPP5E and its product—PtdIns(4)P—accumulate at the centrosome/basal body in non-ciliated, but not ciliated, cells. PtdIns(4)P binding to TTBK2 and the distal appendage protein CEP164 compromises the TTBK2-CEP164 interaction and inhibits the recruitment of TTBK2. Our results reveal that PtdIns(4)P homoeostasis, coordinated by PIPKIγ and INPP5E at the centrosome/ciliary base, is vital for ciliogenesis by regulating the CEP164-dependent recruitment of TTBK2. The primary cilium is essential for embryonic development and tissue pattern formation. Here the authors show that PIPKIγ localizes to the basal body of the primary cilium and cooperates with the Joubert Syndrome associated protein INPP5E to regulate the initiation of ciliogenesis.
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Endocytic pathways and endosomal trafficking: a primer. Wien Med Wochenschr 2016; 166:196-204. [PMID: 26861668 DOI: 10.1007/s10354-016-0432-7] [Citation(s) in RCA: 149] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 01/05/2016] [Indexed: 01/05/2023]
Abstract
This brief overview of endocytic trafficking is written in honor of Renate Fuchs, who retires this year. In the mid-1980s, Renate pioneered studies on the ion-conducting properties of the recently discovered early and late endosomes and the mechanisms governing endosomal acidification. As described in this review, after uptake through one of many mechanistically distinct endocytic pathways, internalized proteins merge into a common early/sorting endosome. From there they again diverge along distinct sorting pathways, back to the cell surface, on to the trans-Golgi network or across polarized cells. Other transmembrane receptors are packaged into intraluminal vesicles of late endosomes/multivesicular bodies that eventually fuse with and deliver their content to lysosomes for degradation. Endosomal acidification, in part, determines sorting along this pathway. We describe other sorting machinery and mechanisms, as well as the rab proteins and phosphatidylinositol lipids that serve to dynamically define membrane compartments along the endocytic pathway.
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Li Z, Yao J, Xie Y, Geng X, Liu Z. Phosphoinositide 3-kinase family in channel catfish and their regulated expression after bacterial infection. FISH & SHELLFISH IMMUNOLOGY 2016; 49:364-373. [PMID: 26772478 DOI: 10.1016/j.fsi.2016.01.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Revised: 12/30/2015] [Accepted: 01/03/2016] [Indexed: 06/05/2023]
Abstract
The phosphoinositide-3-kinase (PI3Ks) family of lipid kinases is widely conserved from yeast to mammals. In this work, we identified a total of 14 members of the PI3Ks from the channel catfish genome and transcriptome and conducted phylogenetic and syntenic analyses of these genes. The expression profiles after infection with Edwardsiella ictaluri and Flavobacterium columnare were examined to determine the involvement of PI3Ks in immune responses after bacterial infection in catfish. The results indicated that PI3Ks genes including all of the catalytic subunit and several regulatory subunits genes were widely regulated after bacterial infection. The expression patterns were quite different when challenged with different bacteria. The PI3Ks were up-regulated rapidly at the early stage after ESC infection, but their induced expression was much slower, at the middle stage after columnaris infection. RNA-Seq datasets indicated that PI3K genes may be expressed at different levels in different catfish differing in their resistance levels against columnaris. Future studies are required to confirm and validate these observations. Taken together, this study indicated that PI3K genes may be involved as a part of the defense responses of catfish after infections, and they could be one of the determinants for disease resistance.
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Affiliation(s)
- Zhaoxia Li
- The Fish Molecular Genetics and Biotechnology Laboratory, Aquatic Genomics Unit, School of Fisheries, Aquaculture and Aquatic Sciences, Auburn University, Auburn, AL 36849, USA; Marine Science and Engineering College, Qingdao Agricultural University, Qingdao 266109, PR China
| | - Jun Yao
- The Fish Molecular Genetics and Biotechnology Laboratory, Aquatic Genomics Unit, School of Fisheries, Aquaculture and Aquatic Sciences, Auburn University, Auburn, AL 36849, USA
| | - Yangjie Xie
- The Fish Molecular Genetics and Biotechnology Laboratory, Aquatic Genomics Unit, School of Fisheries, Aquaculture and Aquatic Sciences, Auburn University, Auburn, AL 36849, USA
| | - Xin Geng
- The Fish Molecular Genetics and Biotechnology Laboratory, Aquatic Genomics Unit, School of Fisheries, Aquaculture and Aquatic Sciences, Auburn University, Auburn, AL 36849, USA
| | - Zhanjiang Liu
- The Fish Molecular Genetics and Biotechnology Laboratory, Aquatic Genomics Unit, School of Fisheries, Aquaculture and Aquatic Sciences, Auburn University, Auburn, AL 36849, USA.
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Cell biology and immunology lessons taught by Legionella pneumophila. SCIENCE CHINA-LIFE SCIENCES 2015; 59:3-10. [PMID: 26596966 DOI: 10.1007/s11427-015-4945-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Accepted: 08/27/2015] [Indexed: 02/08/2023]
Abstract
Legionella pneumophila is a facultative intracellular pathogen capable of replicating within a broad range of hosts. One unique feature of this pathogen is the cohort of ca. 300 virulence factors (effectors) delivered into host cells via its Dot/Icm type IV secretion system. Study of these proteins has produced novel insights into the mechanisms of host function modulation by pathogens, the regulation of essential processes of eukaryotic cells and of immunosurveillance. In this review, we will briefly discuss the roles of some of these effectors in the creation of a niche permissive for bacterial replication in phagocytes and recent advancements in the dissection of the innate immune detection mechanisms by challenging immune cells with L. pneumophila.
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Deranieh RM, Shi Y, Tarsio M, Chen Y, McCaffery JM, Kane PM, Greenberg ML. Perturbation of the Vacuolar ATPase: A NOVEL CONSEQUENCE OF INOSITOL DEPLETION. J Biol Chem 2015; 290:27460-72. [PMID: 26324718 DOI: 10.1074/jbc.m115.683706] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Indexed: 11/06/2022] Open
Abstract
Depletion of inositol has profound effects on cell function and has been implicated in the therapeutic effects of drugs used to treat epilepsy and bipolar disorder. We have previously shown that the anticonvulsant drug valproate (VPA) depletes inositol by inhibiting myo-inositol-3-phosphate synthase, the enzyme that catalyzes the first and rate-limiting step of inositol biosynthesis. To elucidate the cellular consequences of inositol depletion, we screened the yeast deletion collection for VPA-sensitive mutants and identified mutants in vacuolar sorting and the vacuolar ATPase (V-ATPase). Inositol depletion caused by starvation of ino1Δ cells perturbed the vacuolar structure and decreased V-ATPase activity and proton pumping in isolated vacuolar vesicles. VPA compromised the dynamics of phosphatidylinositol 3,5-bisphosphate (PI3,5P2) and greatly reduced V-ATPase proton transport in inositol-deprived wild-type cells. Osmotic stress, known to increase PI3,5P2 levels, did not restore PI3,5P2 homeostasis nor did it induce vacuolar fragmentation in VPA-treated cells, suggesting that perturbation of the V-ATPase is a consequence of altered PI3,5P2 homeostasis under inositol-limiting conditions. This study is the first to demonstrate that inositol depletion caused by starvation of an inositol synthesis mutant or by the inositol-depleting drug VPA leads to perturbation of the V-ATPase.
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Affiliation(s)
- Rania M Deranieh
- From the Department of Biological Sciences, Wayne State University, Detroit, Michigan 48202
| | - Yihui Shi
- From the Department of Biological Sciences, Wayne State University, Detroit, Michigan 48202
| | - Maureen Tarsio
- the Department of Biochemistry and Molecular Biology, State University of New York Upstate Medical University, Syracuse, New York 13210, and
| | - Yan Chen
- From the Department of Biological Sciences, Wayne State University, Detroit, Michigan 48202
| | - J Michael McCaffery
- the Integrated Imaging Center, Department of Biology, Johns Hopkins University, Baltimore, Maryland 21218
| | - Patricia M Kane
- the Department of Biochemistry and Molecular Biology, State University of New York Upstate Medical University, Syracuse, New York 13210, and
| | - Miriam L Greenberg
- From the Department of Biological Sciences, Wayne State University, Detroit, Michigan 48202,
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Svane S, Gorshkov V, Kjeldsen F. Charge inversion of phospholipids by dimetal complexes for positive ion-mode electrospray ionization mass spectrometry analysis. Anal Chem 2015; 87:8732-9. [PMID: 26189465 DOI: 10.1021/acs.analchem.5b01536] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Phospholipids are vital constituents of living cells, as they are involved in signaling and membrane formation. Mass spectrometry analysis of many phospholipids is preferentially performed in the negative ion-mode because of their acidic nature. Here we have studied the potential of a digallium and dizinc complex to charge-invert a range of different types of phospholipids and measured their ion yield and fragmentation behavior in positive ion-mode tandem mass spectrometry. The dimetal complexes bind specifically the phosphate groups of phospholipids and add an excess of up to three positive charges per phosphate group. Three different phosphoinositide phosphates (mono-, di-, and triphosphorylated inositides), a phosphatidic acid, a phosphatidylcholine, a phosphatidylethanolamine, and a phosphatidylglycerol were investigated. The intensities obtained in positive ion-mode of phosphoinositide phosphates and phosphatidic acid bound to {LGa2}(5+) were between 2.5- and 116-fold higher than that of the unmodified lipids in the negative ion-mode. Native phosphoinositide ions yielded upon CID in the negative ion-mode predominantly product ions due to losses of H3PO4, PO3(-) and H2O. In comparison, CID spectra of {LGa2}(5+)-bound phosphoinositides generally resulted in fragment ions corresponding to loss of the full diglyceride chain as well as the remaining headgroup bound to {LGa2}(5+) as the most abundant peaks. A number of signature fragment ions of moderate abundance were observed that allowed for distinction between the three regioisomers of 1,2-di(9Z-octadecenoyl)-sn-glycero-3-[phosphoinositol-x,y-bisphosphate] (PI(3,4)P2, PI(3,5)P2, PI(4,5)P2).
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Affiliation(s)
- Simon Svane
- Department of Biochemistry and Molecular Biology, ‡Department of Physics, Chemistry and Pharmacy, University of Southern Denmark , 5230 Odense M, Denmark
| | - Vladimir Gorshkov
- Department of Biochemistry and Molecular Biology, ‡Department of Physics, Chemistry and Pharmacy, University of Southern Denmark , 5230 Odense M, Denmark
| | - Frank Kjeldsen
- Department of Biochemistry and Molecular Biology, ‡Department of Physics, Chemistry and Pharmacy, University of Southern Denmark , 5230 Odense M, Denmark
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Yoo KY, Son JY, Lee JU, Shin W, Im DW, Kim SJ, Ryu SE, Heo YS. Structure of the catalytic phosphatase domain of MTMR8: implications for dimerization, membrane association and reversible oxidation. ACTA CRYSTALLOGRAPHICA SECTION D: BIOLOGICAL CRYSTALLOGRAPHY 2015; 71:1528-39. [PMID: 26143924 DOI: 10.1107/s139900471500927x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Accepted: 05/15/2015] [Indexed: 11/11/2022]
Abstract
Myotubularin-related proteins are a large family of phosphoinositide phosphatases; their activity, stability and subcellular localization are regulated by dimeric interactions with other members of the family. Here, the crystal structure of the phosphatase domain of MTMR8 is reported. Conformational deviation of the two loops that mediate interaction with the PH-GRAM domain suggests that the PH-GRAM domain interacts differently with the phosphatase domain of each MTMR member. The protein exists as a dimer with twofold symmetry, providing insight into a novel mode of dimerization mediated by the phosphatase domain. Structural comparison and mutation studies suggest that Lys255 of MTMR8 interacts with the substrate diacylglycerol moiety, similar to Lys333 of MTMR2, although the positions of these residues are different. The catalytic activity of the MTMR8 phosphatase domain is inhibited by oxidation and is reversibly reactivated by reduction, suggesting the presence of an oxidation-protective intermediate other than a disulfide bond owing to the absence of a cysteine within a disulfide-bond distance from Cys338.
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Affiliation(s)
- Ki Young Yoo
- Department of Chemistry, Konkuk University, 1 Hwayang-dong, Gwangjin-gu, Seoul 143-701, Republic of Korea
| | - Ji Young Son
- Department of Chemistry, Konkuk University, 1 Hwayang-dong, Gwangjin-gu, Seoul 143-701, Republic of Korea
| | - Jee Un Lee
- Department of Chemistry, Konkuk University, 1 Hwayang-dong, Gwangjin-gu, Seoul 143-701, Republic of Korea
| | - Woori Shin
- Department of Chemistry, Konkuk University, 1 Hwayang-dong, Gwangjin-gu, Seoul 143-701, Republic of Korea
| | - Dong Won Im
- Department of Chemistry, Konkuk University, 1 Hwayang-dong, Gwangjin-gu, Seoul 143-701, Republic of Korea
| | - Seung Jun Kim
- Medical Proteomics Research Center, Korea Research Institute of Bioscience and Biotechnology, 111 Gwahangno, Yuseong-gu, Daejeon 305-806, Republic of Korea
| | - Seong Eon Ryu
- Department of Bio Engineering, Hanyang University, Seongdong-gu, Seoul 133-791, Republic of Korea
| | - Yong Seok Heo
- Department of Chemistry, Konkuk University, 1 Hwayang-dong, Gwangjin-gu, Seoul 143-701, Republic of Korea
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Hsu F, Hu F, Mao Y. Spatiotemporal control of phosphatidylinositol 4-phosphate by Sac2 regulates endocytic recycling. ACTA ACUST UNITED AC 2015; 209:97-110. [PMID: 25869669 PMCID: PMC4395482 DOI: 10.1083/jcb.201408027] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Sac2 (INPP5F) is a phosphoinositide 4-phosphatase that specifically hydrolyzes PI(4)P and regulates endocytic recycling. It is well established that the spatial- and temporal-restricted generation and turnover of phosphoinositides (PIs) by a cascade of PI-metabolizing enzymes is a key regulatory mechanism in the endocytic pathway. Here, we demonstrate that the Sac1 domain–containing protein Sac2 is a PI 4-phosphatase that specifically hydrolyzes phosphatidylinositol 4-phosphate in vitro. We further show that Sac2 colocalizes with early endosomal markers and is recruited to transferrin (Tfn)-containing vesicles during endocytic recycling. Exogenous expression of the catalytically inactive mutant Sac2C458S resulted in altered cellular distribution of Tfn receptors and delayed Tfn recycling. Furthermore, genomic ablation of Sac2 caused a similar perturbation on Tfn and integrin recycling as well as defects in cell migration. Structural characterization of Sac2 revealed a unique pleckstrin-like homology Sac2 domain conserved in all Sac2 orthologues. Collectively, our findings provide evidence for the tight regulation of PIs by Sac2 in the endocytic recycling pathway.
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Affiliation(s)
- FoSheng Hsu
- Weill Institute for Cell and Molecular Biology and Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853
| | - Fenghua Hu
- Weill Institute for Cell and Molecular Biology and Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853
| | - Yuxin Mao
- Weill Institute for Cell and Molecular Biology and Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853
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Protein kinase D1/2 is involved in the maturation of multivesicular bodies and secretion of exosomes in T and B lymphocytes. Cell Death Differ 2015; 23:99-109. [PMID: 26045048 DOI: 10.1038/cdd.2015.72] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Revised: 04/22/2015] [Accepted: 04/28/2015] [Indexed: 12/26/2022] Open
Abstract
Multivesicular bodies (MVBs) are endocytic compartments that enclose intraluminal vesicles (ILVs) formed by inward budding from the limiting membrane of endosomes. In T lymphocytes, these ILV contain Fas ligand (FasL) and are secreted as 'lethal exosomes' following activation-induced fusion of the MVB with the plasma membrane. Diacylglycerol (DAG) and diacylglycerol kinase α (DGKα) regulate MVB maturation and polarized traffic, as well as subsequent secretion of pro-apoptotic exosomes, but the molecular basis underlying these phenomena remains unclear. Here we identify protein kinase D (PKD) family members as DAG effectors involved in MVB genesis and secretion. We show that the inducible secretion of exosomes is enhanced when a constitutively active PKD1 mutant is expressed in T lymphocytes, whereas exosome secretion is impaired in PKD2-deficient mouse T lymphoblasts and in PKD1/3-null B cells. Analysis of PKD2-deficient T lymphoblasts showed the presence of large, immature MVB-like vesicles and demonstrated defects in cytotoxic activity and in activation-induced cell death. Using pharmacological and genetic tools, we show that DGKα regulates PKD1/2 subcellular localization and activation. Our studies demonstrate that PKD1/2 is a key regulator of MVB maturation and exosome secretion, and constitutes a mediator of the DGKα effect on MVB secretory traffic.
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Influence of cellular trafficking pathway on bluetongue virus infection in ovine cells. Viruses 2015; 7:2378-403. [PMID: 25984713 PMCID: PMC4452911 DOI: 10.3390/v7052378] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Accepted: 05/06/2015] [Indexed: 11/27/2022] Open
Abstract
Bluetongue virus (BTV), a non-enveloped arbovirus, causes hemorrhagic disease in ruminants. However, the influence of natural host cell proteins on BTV replication process is not defined. In addition to cell lysis, BTV also exits non-ovine cultured cells by non-lytic pathways mediated by nonstructural protein NS3 that interacts with virus capsid and cellular proteins belonging to calpactin and ESCRT family. The PPXY late domain motif known to recruit NEDD4 family of HECT ubiquitin E3 ligases is also highly conserved in NS3. In this study using a mixture of molecular, biochemical and microscopic techniques we have analyzed the importance of ovine cellular proteins and vesicles in BTV infection. Electron microscopic analysis of BTV infected ovine cells demonstrated close association of mature particles with intracellular vesicles. Inhibition of Multi Vesicular Body (MVB) resident lipid phosphatidylinositol-3-phosphate resulted in decreased total virus titre suggesting that the vesicles might be MVBs. Proteasome mediated inhibition of ubiquitin or modification of virus lacking the PPXY in NS3 reduced virus growth. Thus, our study demonstrated that cellular components comprising of MVB and exocytic pathways proteins are involved in BTV replication in ovine cells.
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44
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Beretta M, Bauer M, Hirsch E. PI3K signaling in the pathogenesis of obesity: The cause and the cure. Adv Biol Regul 2015; 58:1-15. [PMID: 25512233 DOI: 10.1016/j.jbior.2014.11.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Revised: 11/21/2014] [Accepted: 11/21/2014] [Indexed: 06/04/2023]
Abstract
With the steady rise in the incidence of obesity and its associated comorbidities, in the last decades research aimed at understanding molecular mechanisms that control body weight has gained new interest. Fat gain is frequently associated with chronic adipose tissue inflammation and with peripheral as well as central metabolic derangements, resulting in an impaired hypothalamic regulation of energy homeostasis. Recent attention has focused on the role of phosphatidylinositol 3-kinase (PI3K) in both immune and metabolic response pathways, being involved in the pathophysiology of obesity and its associated metabolic diseases. In this review, we focus on distinct PI3K isoforms, especially class I PI3Ks, mediating inflammatory cells recruitment to the enlarged fat as well as intracellular responses to key hormonal regulators of fat storage, both in adipocytes and in the central nervous system. This integrated view of PI3K functions may ultimately help to develop new therapeutic interventions for the treatment of obesity.
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Affiliation(s)
- Martina Beretta
- Molecular Biotechnology Center, University of Torino, Torino, Italy; Department of Anesthesiology and Intensive Care Medicine, Jena University Hospital, Jena, Germany
| | - Michael Bauer
- Department of Anesthesiology and Intensive Care Medicine, Jena University Hospital, Jena, Germany
| | - Emilio Hirsch
- Molecular Biotechnology Center, University of Torino, Torino, Italy.
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de Azevedo-Martins AC, Alves JMP, de Mello FG, Vasconcelos ATR, de Souza W, Einicker-Lamas M, Motta MCM. Biochemical and phylogenetic analyses of phosphatidylinositol production in Angomonas deanei, an endosymbiont-harboring trypanosomatid. Parasit Vectors 2015; 8:247. [PMID: 25903782 PMCID: PMC4424895 DOI: 10.1186/s13071-015-0854-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Accepted: 04/13/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The endosymbiosis in trypanosomatids is characterized by co-evolution between one bacterium and its host protozoan in a mutualistic relationship, thus constituting an excellent model to study organelle origin in the eukaryotic cell. In this association, an intense metabolic exchange is observed between both partners: the host provides energetic molecules and a stable environment to a reduced wall symbiont, while the bacterium is able to interfere in host metabolism by enhancing phospholipid production and completing essential biosynthesis pathways, such as amino acids and hemin production. The bacterium envelope presents a reduced cell wall which is mainly composed of cardiolipin and phosphatidylcholine, being the latter only common in intracellular prokaryotes. Phosphatidylinositol (PI) is also present in the symbiont and host cell membranes. This phospholipid is usually related to cellular signaling and to anchor surface molecules, which represents important events for cellular interactions. METHODS In order to investigate the production of PI and its derivatives in symbiont bearing trypanosomatids, aposymbiotic and wild type strains of Angomonas deanei, as well as isolated symbionts, were incubated with [(3)H]myo-inositol and the incorporation of this tracer was analyzed into inositol-containing molecules, mainly phosphoinositides and lipoproteins. Gene searches and their phylogenies were also performed in order to investigate the PI synthesis in symbiontbearing trypanosomatids. RESULTS Our results showed that the bacterium did not incorporate the tracer and that both strains produced similar quantities of PI and its derivatives, indicating that the symbiont does not influence the production of these metabolites. Gene searches related to PI synthesis revealed that the trypanosomatid genome contains an inositol transporter, PI synthase and the myo-inositol synthase. Thus, the host is able to produce PI either from exogenous myo-inositol (inositol transporter) or from myo-inositol synthesized de novo. Phylogenetic analysis using other organisms as references indicated that, in trypanosomatids, the genes involved in PI synthesis have a monophyletic origin. In accordance with experimental data, sequences for myo-inositol transport or for myo-inositol and PI biosynthesis were not found in the symbiont. CONCLUSIONS Altogether, our results indicate that the bacterium depends on the host to obtain PI.
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Affiliation(s)
- Allan C de Azevedo-Martins
- Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, UFRJ, Avenida Carlos Chagas Filho, 343, Bloco G, Subsolo, Cidade Universitária, Ilha do Fundão, Rio de Janeiro, CEP 21941-590, Brazil. .,Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagens, Rio de Janeiro, Brazil. .,Laboratório Nacional de Computação Científica, Av. Getúlio Vargas, 333, Quitandinha, Petrópolis, RJ, CEP: 25651-075, Brazil.
| | - João M P Alves
- Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil.
| | - Fernando Garcia de Mello
- Laboratório de Neuroquímica, Instituto de Biofísica Carlos Chagas Filho, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, UFRJ, Avenida Carlos Chagas Filho, 343, Bloco C, Cidade Universitária, Ilha do Fundão, Rio de Janeiro, CEP 21941-590, Brazil.
| | - Ana Tereza R Vasconcelos
- Laboratório Nacional de Computação Científica, Av. Getúlio Vargas, 333, Quitandinha, Petrópolis, RJ, CEP: 25651-075, Brazil.
| | - Wanderley de Souza
- Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, UFRJ, Avenida Carlos Chagas Filho, 343, Bloco G, Subsolo, Cidade Universitária, Ilha do Fundão, Rio de Janeiro, CEP 21941-590, Brazil. .,Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagens, Rio de Janeiro, Brazil. .,Instituto Nacional de Metrologia, Qualidade e Tecnologia - Inmetro, Rio de Janeiro, RJ, Brasil.
| | - Marcelo Einicker-Lamas
- Laboratório de Biomembranas, Instituto de Biofísica Carlos Chagas Filho, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, UFRJ, Avenida Carlos Chagas Filho, 343, Bloco G, Cidade Universitária, Ilha do Fundão, Rio de Janeiro, CEP 21941-590, Brazil.
| | - Maria Cristina M Motta
- Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, UFRJ, Avenida Carlos Chagas Filho, 343, Bloco G, Subsolo, Cidade Universitária, Ilha do Fundão, Rio de Janeiro, CEP 21941-590, Brazil. .,Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagens, Rio de Janeiro, Brazil.
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Li J, Zhao WG, Shen ZF, Yuan T, Liu SN, Liu Q, Fu Y, Sun W. Comparative proteome analysis of brown adipose tissue in obese C57BL/6J mice using iTRAQ-coupled 2D LC-MS/MS. PLoS One 2015; 10:e0119350. [PMID: 25747866 PMCID: PMC4352050 DOI: 10.1371/journal.pone.0119350] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Accepted: 01/12/2015] [Indexed: 12/14/2022] Open
Abstract
High-fat diet (HFD) leads to the development of obesity accompanied by insulin resistance, which increases the risk of type 2 diabetes mellitus and cardiovascular disease. Brown adipose tissue (BAT) plays an essential role in energy metabolism, thus it will give us promising treatment targets through elucidating underlying mechanisms of BAT in obesity. In this study, female C57BL/6J mice were fed HFD or normal diet (ND) for 22 weeks. Hyperinsulinemic-euglycemic clamp was performed to evaluate insulin sensitivity, which was independently correlated with obesity. Using isobaric tag for relative and absolute quantification (iTRAQ) coupled with 2D LC-MS/MS, we quantitated 3048 proteins in BAT. As compared HFD with ND, we obtained 727 differentially expressed proteins. Functional analysis found that those proteins were mainly assigned to the pathway of mitochondrial function. In this pathway, carnitine O-palmitoyltransferase 2 (CPT2), uncoupling protein 1 (UCP1) and apoptosis-inducing factor 1 (AIF1) were up-regulated significantly by HFD, and they were confirmed by western blotting. The results indicated that HFD might induce the apoptosis of brown adipocytes via the up-regulated AIF1. Meanwhile, HFD also stimulated fatty acid β-oxidation and raised compensatory energy consuming through the increases of CPT2 and UCP1, respectively. However, the apoptosis of brown adipocytes might weaken the compensatory energy expenditure, and finally contribute to overweight/obesity. So, preventing the apoptosis of brown adipocytes may be the key target to treat obesity.
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Affiliation(s)
- Juan Li
- Department of Endocrinology, Key Laboratory of Endocrinology of Ministry of Health, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - Wei-Gang Zhao
- Department of Endocrinology, Key Laboratory of Endocrinology of Ministry of Health, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
- * E-mail: (WGZ); (WS)
| | - Zhu-Fang Shen
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Diabetes Research Center of Chinese Academy of Medical Sciences, Beijing, China
| | - Tao Yuan
- Department of Endocrinology, Key Laboratory of Endocrinology of Ministry of Health, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - Shuai-Nan Liu
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Diabetes Research Center of Chinese Academy of Medical Sciences, Beijing, China
| | - Quan Liu
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Diabetes Research Center of Chinese Academy of Medical Sciences, Beijing, China
| | - Yong Fu
- Department of Endocrinology, Key Laboratory of Endocrinology of Ministry of Health, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - Wei Sun
- Core Facility of Instrument, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences/School of Basic Medicine, Peking Union Medical College, Beijing, China
- * E-mail: (WGZ); (WS)
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Rai MN, Sharma V, Balusu S, Kaur R. An essential role for phosphatidylinositol 3-kinase in the inhibition of phagosomal maturation, intracellular survival and virulence inCandida glabrata. Cell Microbiol 2014; 17:269-87. [DOI: 10.1111/cmi.12364] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Revised: 08/29/2014] [Accepted: 09/10/2014] [Indexed: 02/03/2023]
Affiliation(s)
- Maruti Nandan Rai
- Laboratory of Fungal Pathogenesis; Centre for DNA Fingerprinting and Diagnostics; Hyderabad Telangana India
| | - Vandana Sharma
- Laboratory of Fungal Pathogenesis; Centre for DNA Fingerprinting and Diagnostics; Hyderabad Telangana India
| | - Sriram Balusu
- Laboratory of Fungal Pathogenesis; Centre for DNA Fingerprinting and Diagnostics; Hyderabad Telangana India
| | - Rupinder Kaur
- Laboratory of Fungal Pathogenesis; Centre for DNA Fingerprinting and Diagnostics; Hyderabad Telangana India
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48
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Chen M, Wu J, Liang N, Tang L, Chen Y, Chen H, Wei W, Wei T, Huang H, Yi X, Qi M. Identification of a novel SBF2 frameshift mutation in charcot-marie-tooth disease type 4B2 using whole-exome sequencing. GENOMICS PROTEOMICS & BIOINFORMATICS 2014; 12:221-7. [PMID: 25462154 PMCID: PMC4411414 DOI: 10.1016/j.gpb.2014.09.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/07/2014] [Revised: 09/15/2014] [Accepted: 09/18/2014] [Indexed: 12/16/2022]
Abstract
Charcot–Marie–Tooth disease type 4B2 with early-onset glaucoma (CMT4B2, OMIM 604563) is a genetically-heterogeneous childhood-onset neuromuscular disorder. Here, we report the case of a 15-year-old male adolescent with lower extremity weakness, gait abnormalities, foot deformities and early-onset glaucoma. Since clinical diagnosis alone was insufficient for providing pathogenetic evidence to indicate that the condition belonged to a consanguineous family, we applied whole-exome sequencing to samples from the patient, his parents and his younger brother, assuming that the patient’s condition is transmitted in an autosomal recessive pattern. A frame-shift mutation, c.4571delG (P.Gly1524Glufs∗42), was revealed in the CMT4B2-related gene SBF2 (also known as MTMR13, MIM 607697), and this mutation was found to be homozygous in the proband and heterozygous in his parents and younger brother. Together with the results of clinical diagnosis, this case was diagnosed as CMT4B2. Our finding further demonstrates the use of whole-exome sequencing in the diagnosis and treatment of rare diseases.
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Affiliation(s)
- Meiyan Chen
- BGI-Shenzhen, Shenzhen, Guangdong 518083, China
| | - Jing Wu
- BGI-Shenzhen, Shenzhen, Guangdong 518083, China
| | - Ning Liang
- School of Life Sciences, The Chinese University of Hong Kong, NT, Hong Kong SAR 999077, China
| | - Lihui Tang
- BGI-Shenzhen, Shenzhen, Guangdong 518083, China
| | - Yanhua Chen
- BGI-Shenzhen, Shenzhen, Guangdong 518083, China
| | | | - Wei Wei
- BGI-Shenzhen, Shenzhen, Guangdong 518083, China
| | - Tianying Wei
- Center for Genetic and Genomic Medicine, Zhejiang University School of Medicine, First Affiliated Hospital and James D. Watson Institute of Genome Sciences, Hangzhou 310006, China
| | - Hui Huang
- BGI-Shenzhen, Shenzhen, Guangdong 518083, China
| | - Xin Yi
- BGI-Shenzhen, Shenzhen, Guangdong 518083, China.
| | - Ming Qi
- BGI-Shenzhen, Shenzhen, Guangdong 518083, China; Center for Genetic and Genomic Medicine, Zhejiang University School of Medicine, First Affiliated Hospital and James D. Watson Institute of Genome Sciences, Hangzhou 310006, China; Department of Pathology, University of Rochester Medical Center, Rochester, NY 14642, USA.
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49
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Liu C, Qu L, Lian S, Tian Z, Zhao C, Meng L, Shou C. Unconventional secretion of synuclein-γ promotes tumor cell invasion. FEBS J 2014; 281:5159-71. [PMID: 25229320 DOI: 10.1111/febs.13055] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Revised: 09/04/2014] [Accepted: 09/15/2014] [Indexed: 12/21/2022]
Abstract
Synuclein-γ (SNCG) is a chaperone protein and exists mainly in the cytoplasm. SNCG confers chemoresistance, and is a potential unfavorable biomarker for multiple types of cancer. Our previous work demonstrated that SNCG could be detected in the serum of cancer patients and the medium of cultured cancer cells, but the mechanism of SNCG secretion and its biological roles are unknown. Here, we showed that SNCG levels in the culture medium were positively correlated with cancer cell densities and the concentrations of fetal bovine serum added. SNCG secretion was unaffected by brefeldin A, an inhibitor of the classic protein transport pathway, but was antagonized by exosome inhibitor, lysosome inhibitor, ABC transporter inhibitor, and phosphatidylinositide 3-kinase inhibitor, and knockdown of Rab27a. Ultracentrifugation fractionation revealed that intracellular SNCG was present as both free and vesicle-associated forms, but that the extracellular SNCG was mainly free. The results of reciprocal coimmunoprecipitation experiments showed an interaction between SNCG and flotillin-2, a marker of exosomes and lipid rafts. Moreover, we demonstrated that SNCG, both secreted from tumor cells and exogenously added, markedly promoted cancer cell migration and invasion, but had no effect on noncancerous cells. These findings suggest that SNCG is actively secreted by cancer cells via an unconventional secretion pathway and contributes to aggressive phenotypes of cancer cells.
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Affiliation(s)
- Caiyun Liu
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Department of Biochemistry & Molecular Biology, Peking University Cancer Hospital & Institute, Beijing, China
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50
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Hsu F, Mao Y. The structure of phosphoinositide phosphatases: Insights into substrate specificity and catalysis. Biochim Biophys Acta Mol Cell Biol Lipids 2014; 1851:698-710. [PMID: 25264170 DOI: 10.1016/j.bbalip.2014.09.015] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Revised: 09/10/2014] [Accepted: 09/17/2014] [Indexed: 12/17/2022]
Abstract
Phosphoinositides (PIs) are a group of key signaling and structural lipid molecules involved in a myriad of cellular processes. PI phosphatases, together with PI kinases, are responsible for the conversion of PIs between distinctive phosphorylation states. PI phosphatases are a large collection of enzymes that are evolved from at least two disparate ancestors. One group is distantly related to endonucleases, which apply divalent metal ions for phosphoryl transfer. The other group is related to protein tyrosine phosphatases, which contain a highly conserved active site motif Cys-X5-Arg (CX5R). In this review, we focus on structural insights to illustrate current understandings of the molecular mechanisms of each PI phosphatase family, with emphasis on their structural basis for substrate specificity determinants and catalytic mechanisms. This article is part of a Special Issue entitled Phosphoinositides.
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Affiliation(s)
- FoSheng Hsu
- Weill Institute for Cell and Molecular Biology and Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Yuxin Mao
- Weill Institute for Cell and Molecular Biology and Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA.
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