Amphotropic murine leukemia virus is preferentially attached to cholesterol-rich microdomains after binding to mouse fibroblasts.
BACKGROUND
We have recently shown that amphotropic murine leukemia virus (A-MLV) can enter the mouse fibroblast cell line NIH3T3 via caveola-dependent endocytosis. But due to the size and omega-like shape of caveolae it is possible that A-MLV initially binds cells outside of caveolae. Rafts have been suggested to be pre-caveolae and we here investigate whether A-MLV initially binds to its receptor Pit2, a sodium-dependent phosphate transporter, in rafts or caveolae or outside these cholesterol-rich microdomains.


RESULTS
Here, we show that a high amount of cell-bound A-MLV was attached to large rafts of NIH3T3 at the time of investigation. These large rafts were not enriched in caveolin-1, a major structural component of caveolae. In addition, they are rather of natural occurrence in NIH3T3 cells than a result of patching of smaller rafts by A-MLV. Thus cells incubated in parallel with vesicular stomatitis virus glycoprotein (VSV-G) pseudotyped MLV particles showed the same pattern of large rafts as cells incubated with A-MLV, but VSV-G pseudotyped MLV particles did not show any preference to attach to these large microdomains.


CONCLUSIONS
The high concentration of A-MLV particles bound to large rafts of NIH3T3 cells suggests a role of these microdomains in early A-MLV binding events.
Institute of Clinical Medicine and Department of Molecular Biology, University of Aarhus, Aarhus, Denmark. chb@mb.au.dk
Christiane
C
Beer
Lene
L
Pedersen
D000818:Animals; D021941:Caveolae / Q000378:metabolism / Q000821:virology; D002462:Cell Membrane / Q000737:chemistry / Q000821:virology; D002784:Cholesterol / Q000378:metabolism*; D005347:Fibroblasts / Q000378:metabolism / Q000821:virology*; D019084:Fluorescent Antibody Technique, Indirect / Q000379:methods; D009052:Leukemia Virus, Murine / Q000378:metabolism*; D021962:Membrane Microdomains / Q000737:chemistry / Q000378:metabolism* / Q000821:virology*; D051379:Mice; D041681:NIH 3T3 Cells; D049128:Sphingolipid Activator Proteins / Q000378:metabolism
D049128:Sphingolipid Activator Proteins; D002784:Cholesterol