FIG. 1.

TVA800 is associated with DRMs but TVA950 is not. Transfected human 293 cells expressing the lipid raft marker Gαi-DsRed and either TVA800 or TVA950 were either left untreated (A, C, and E) or were treated for 15 min at 37°C with 15 mM MβCD prior to ice-cold Triton X-100 lysis and sucrose gradient sedimentation (B and D). Fractions of each gradient were subjected to electrophoresis on a 12% polyacrylamide gel containing SDS followed by immunoblotting with an antibody specific for DsRed (13) (A and B) or with a subgroup A SU-immunoglobulin fusion protein (38) to detect TVA800 (C and D) or TVA950 (E). The relative levels of TVA800 in different fractions of the sucrose gradients prepared with samples from untreated or MβCD-treated cells (F) were measured using quantitative immunoblotting. The figure shown is representative of such an experiment. The mean and standard deviations of TVA800 levels in both soluble and lipid raft fractions were calculated from three independent experiments.