The alphavirus 6K protein activates endogenous ionic conductances when expressed in Xenopus oocytes

Autor: Jean Dubuisson, Anne Fréderique Antoine, Edith Browaeys-Poly, Katia Cailliau, Claire Montpellier, Jean-Pierre Vilain
Přispěvatelé: Laboratoire de Régulation des Signaux de Division, Université de Lille, Sciences et Technologies, Assemblage et réplication du virus de l'hépatite C (ARVHC), Centre National de la Recherche Scientifique (CNRS), Institut Pasteur de Lille, Réseau International des Instituts Pasteur (RIIP), This work was supported by a microbiology program from the French Ministry of Research, the CNRS (project ACIM-1–4) and the Nord Pas de Calais Region. J. D. is an international scholar of the Howard Hughes Medical Institute., We gratefully appreciate the help provided by A. Lescuyer and S. Ung. We are grateful to Charles M. Rice (Rockefeller University, New York, NY) for providing plasmid pToto1101.
Rok vydání: 2006
Předmět:
Gene Expression Regulation
Viral
Sindbis virus
Physiology
Xenopus
Biophysics
chemistry.chemical_element
MESH: Viral Envelope Proteins/physiology
Alphavirus
Calcium
MESH: Chlorides/metabolism
03 medical and health sciences
Xenopus laevis
Downregulation and upregulation
Chlorides
Viral Envelope Proteins
MESH: Xenopus laevis
Chloride Channels
MESH: Chloride Channels/metabolism
Animals
MESH: Animals
MESH: Xenopus
030304 developmental biology
Calcium metabolism
0303 health sciences
biology
Endoplasmic reticulum
MESH: Oocytes/metabolism
MESH: Calcium/metabolism
030302 biochemistry & molecular biology
Cell Biology
biology.organism_classification
Store-operated calcium entry
MESH: Viral Envelope Proteins/biosynthesis
Cell biology
chemistry
MESH: Calcium Channels/metabolism
[SDV.MP.VIR]Life Sciences [q-bio]/Microbiology and Parasitology/Virology
MESH: Gene Expression Regulation
Viral/physiology
MESH: Viral Envelope Proteins/genetics
Oocytes
Female
Calcium Channels
MESH: Female
MESH: Alphavirus/physiology
Zdroj: Journal of Membrane Biology
Journal of Membrane Biology, Springer Verlag (Germany), 2007, 215, pp.37-48. ⟨10.1007/s00232-007-9003-6⟩
ISSN: 0022-2631
1432-1424
DOI: 10.1007/s00232-007-9003-6⟩
Popis: The Alphavirus Sindbis 6K protein is involved in several functions. It contributes to the processing and membrane insertion of E1 and PE2 viral envelope glycoproteins and to virus budding. It also permeabilizes Escherichia coli and mammalian cells. These viroporin-like properties have been proposed to help virus budding by modifying membrane permeabilities. We expressed Sindbis virus 6K cRNA in Xenopus oocytes to further characterize the effect of 6K on membrane conductances and permeabilization. Although no intrinsic channel properties were seen, cell shrinkage was observed within 24 h. Voltage-clamp experiments showed that 6K upregulated endogenous currents: a hyperpolarization-activated inward current (I in) and a calcium-dependent chloride current (I Cl). 6K was located at both the plasma and the endoplasmic reticulum membranes. The plasma membrane current upregulation likely results from disruption of the calcium homeostasis of the cell at the endoplasmic reticulum level. Indeed, 6K cRNA expression induced reticular calcium store depletion and capacitative calcium entry activation. By experimental modifications of the incubation medium, we showed that downstream of these events cell shrinkage resulted from a 6K -induced KCl efflux (I Cl upregulation leads to chloride efflux, which itself electrically drives potassium efflux), which was responsible for an osmotic water efflux. Our data confirm that 6K specifically triggers a sequential cascade of events that leads to cytoplasmic calcium elevation and cell permeabilization, which likely play a role in the Sindbis virus life cycle.
Databáze: OpenAIRE
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