33
views
0
recommends
+1 Recommend
0 collections
    0
    shares
      • Record: found
      • Abstract: found
      • Article: found
      Is Open Access

      The Ebola Virus matrix protein, VP40, requires phosphatidylinositol 4,5-bisphosphate (PI(4,5)P 2) for extensive oligomerization at the plasma membrane and viral egress

      research-article

      Read this article at

      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          VP40 is one of eight proteins encoded by the Ebola Virus (EBOV) and serves as the primary matrix protein, forming virus like particles (VLPs) from mammalian cells without the need for other EBOV proteins. While VP40 is required for viral assembly and budding from host cells during infection, the mechanisms that target VP40 to the plasma membrane are not well understood. Phosphatidylserine is required for VP40 plasma membrane binding, VP40 hexamer formation, and VLP egress, However, PS also becomes exposed on the outer membrane leaflet at sites of VP40 budding, raising the question of how VP40 maintains an interaction with the plasma membrane inner leaflet when PS is flipped to the opposite side. To address this question, cellular and in vitro assays were employed to determine if phosphoinositides are important for efficient VP40 localization to the plasma membrane. Cellular studies demonstrated that PI(4,5)P 2 was an important component of VP40 assembly at the plasma membrane and subsequent virus like particle formation. Additionally, PI(4,5)P 2 was required for formation of extensive oligomers of VP40, suggesting PS and PI(4,5)P 2 have different roles in VP40 assembly where PS regulates formation of hexamers from VP40 dimers and PI(4,5)P 2 stabilizes and/or induces extensive VP40 oligomerization at the plasma membrane.

          Related collections

          Most cited references43

          • Record: found
          • Abstract: found
          • Article: not found

          Membrane phosphatidylserine regulates surface charge and protein localization.

          Electrostatic interactions with negatively charged membranes contribute to the subcellular targeting of proteins with polybasic clusters or cationic domains. Although the anionic phospholipid phosphatidylserine is comparatively abundant, its contribution to the surface charge of individual cellular membranes is unknown, partly because of the lack of reagents to analyze its distribution in intact cells. We developed a biosensor to study the subcellular distribution of phosphatidylserine and found that it binds the cytosolic leaflets of the plasma membrane, as well as endosomes and lysosomes. The negative charge associated with the presence of phosphatidylserine directed proteins with moderately positive charge to the endocytic pathway. More strongly cationic proteins, normally associated with the plasma membrane, relocalized to endocytic compartments when the plasma membrane surface charge decreased on calcium influx.
            Bookmark
            • Record: found
            • Abstract: found
            • Article: not found

            X-ray structure of a calcium-activated TMEM16 lipid scramblase.

            The TMEM16 family of proteins, also known as anoctamins, features a remarkable functional diversity. This family contains the long sought-after Ca(2+)-activated chloride channels as well as lipid scramblases and cation channels. Here we present the crystal structure of a TMEM16 family member from the fungus Nectria haematococca that operates as a Ca(2+)-activated lipid scramblase. Each subunit of the homodimeric protein contains ten transmembrane helices and a hydrophilic membrane-traversing cavity that is exposed to the lipid bilayer as a potential site of catalysis. This cavity harbours a conserved Ca(2+)-binding site located within the hydrophobic core of the membrane. Mutations of residues involved in Ca(2+) coordination affect both lipid scrambling in N. haematococca TMEM16 and ion conduction in the Cl(-) channel TMEM16A. The structure reveals the general architecture of the family and its mode of Ca(2+) activation. It also provides insight into potential scrambling mechanisms and serves as a framework to unravel the conduction of ions in certain TMEM16 proteins.
              Bookmark
              • Record: found
              • Abstract: found
              • Article: not found

              Receptor-induced transient reduction in plasma membrane PtdIns(4,5)P2 concentration monitored in living cells.

              Although phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P2) is a well-characterized precursor for the second messengers inositol 1,4,5-trisphosphate, diacylglycerol [1] and phosphatidylinositol 3,4,5-trisphosphate [2], it also interacts with the actin-binding proteins profilin and gelsolin [3], as well as with many signaling molecules that contain pleckstrin homology (PH) domains [4]. It is conceivable that stimuli received by receptors in the plasma membrane could be sufficiently strong to decrease the PtdIns(4,5)P2 concentration; this decrease could alter the structure of the cortical cytoskeleton and modulate the activity of signaling molecules that have PH domains. Here, we tested this hypothesis by using an in vivo fluorescent indicator for PtdIns(4,5)P2, by tagging the PH domain of phospholipase C delta 1 (PLC-delta 1) with the green fluorescent protein (GFP-PH). When expressed in cells, GFP-PH was found to be enriched at the plasma membrane. Binding studies in vitro and mutant analysis suggested that GFP-PH bound PtdIns(4,5)P2 selectively over other phosphatidylinositol lipids. Strikingly, receptor stimulation induced a transient dissociation of GFP-PH from the plasma membrane, suggesting that the concentration of PtdIns(4,5)P2 in the plasma membrane was effectively lowered. This transient dissociation was blocked by the PLC inhibitor U73122 but was not affected by the phosphoinositide (PI) 3-kinase inhibitor wortmannin, suggesting that it is mostly mediated by PLC and not by PI 3-kinase activation. Overall, our studies show that PtdIns(4,5)P2 can have second messenger functions of its own, by mediating a transient dissociation of proteins anchored in the plasma membrane.
                Bookmark

                Author and article information

                Journal
                Sci Rep
                Sci Rep
                Scientific Reports
                Nature Publishing Group
                2045-2322
                12 January 2016
                2016
                : 6
                : 19125
                Affiliations
                [1 ]Department of Chemistry and Biochemistry, the Eck Institute for Global Health, and the Boler-Parseghian Center for Rare and Neglected Diseases, University of Notre Dame , Notre Dame, Indiana, 46556
                [2 ]Department of Biochemistry and Molecular Biology, Indiana University School of Medicine-South Bend , South Bend, Indiana 46617.
                Author notes
                Article
                srep19125
                10.1038/srep19125
                4709572
                26753796
                bbc6c5bf-6b89-4761-b022-58e65113e26d
                Copyright © 2016, Macmillan Publishers Limited

                This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/

                History
                : 02 September 2015
                : 07 December 2015
                Categories
                Article

                Uncategorized
                Uncategorized

                Comments

                Comment on this article