Rafts promote assembly and atypical targeting of a nonenveloped virus, rotavirus, in Caco-2 cells.
Rotavirus follows an atypical pathway to the apical membrane of intestinal cells that bypasses the Golgi. The involvement of rafts in this process was explored here. VP4 is the most peripheral protein of the triple-layered structure of this nonenveloped virus. High proportions of VP4 associated with rafts within the cell as early as 3 h postinfection. In the meantime a significant part of VP4 was targeted to the Triton X-100-resistant microdomains of the apical membrane, suggesting that this protein possesses an autonomous signal for its targeting. At a later stage the other structural rotavirus proteins were also found in rafts within the cells together with NSP4, a nonstructural protein required for the final stage of virus assembly. Rafts purified from infected cells were shown to contain infectious particles. Finally purified VP4 and mature virus were shown to interact with cholesterol- and sphingolipid-enriched model lipid membranes that changed their phase preference from inverted hexagonal to lamellar structures. Together these results indicate that a direct interaction of VP4 with rafts promotes assembly and atypical targeting of rotavirus in intestinal cells.
Sapin
Catherine
C
INSERM U 538, CHU Saint Antoine, Université Pierre et Marie Curie, 75012 Paris, France.
Colard
Odile
O
Delmas
Olivier
O
Tessier
Cedric
C
Breton
Michelyne
M
Enouf
Vincent
V
Chwetzoff
Serge
S
Ouanich
Jocelyne
J
Cohen
Jean
J
Wolf
Claude
C
Trugnan
Germain
G
D018938:Caco-2 Cells / Q000821:virology*; D002213:Capsid / Q000378:metabolism*; D036022:Capsid Proteins; D002462:Cell Membrane / Q000187:drug effects; D004351:Drug Resistance; D006801:Humans; D021962:Membrane Microdomains / Q000187:drug effects / Q000378:metabolism*; D017830:Octoxynol / Q000494:pharmacology; D012401:Rotavirus / Q000378:metabolism / Q000472:pathogenicity*; D019065:Virus Assembly
D036022:Capsid Proteins; C060339:VP4 protein, Rotavirus; D017830:Octoxynol