Amphotropic murine leukaemia virus envelope protein is associated with cholesterol-rich microdomains

Background: Cholesterol-rich microdomains like lipid rafts were recently identified as regions within the plasma membrane, which play an important role in the assembly and budding of different viruses, e. g., measles virus and human immunodeficiency virus. For these viruses association of newly synthesized viral proteins with lipid rafts has been shown. Results: Here we provide evidence for the association of the envelope protein (Env) of the 4070A isolate of amphotropic murine leukaemia virus (A-MLV) with lipid rafts. Using density gradient centrifugation and immunocytochemical analyses, we show that Env co-localizes with cholesterol, ganglioside GM1 and caveolin-1 in these specific regions of the plasma membrane. Conclusions: These results show that a large amount of A-MLV Env is associated with lipid rafts and suggest that cholesterol-rich microdomains are used as portals for the exit of A-MLV.