Figure 1.
Characterization of raft and nonraft fractions isolated from PC12 cells and caveolin expression in PC12 cells. PC12 cells were solubilized in 1% Triton X-100 and fractionated on a discontinuous sucrose gradient, as detailed in Materials and Methods. (A) The protein content of gradient fractions shown as a percentage of the total protein on the gradient. (B) Equal volumes of the gradient fractions were separated by SDS/PAGE and transferred to nitrocellulose for immunoblotting analysis by using antibodies specific for flotillin, α1 subunit of the NaK ATPase and the transferrin receptor (TfR). (C) Similar amounts of protein from fraction 12 (nonraft) and fraction 5 (raft) were separated by SDS/PAGE and stained with Coomassie blue. Differences between the protein profiles are highlighted by lines and asterisks. (D) Homogenates prepared from 3T3-L1 adipocytes (A), L6 skeletal muscle cells (M), endothelium (E), brain (B) and PC12 cells (P) were separated by SDS/PAGE and transferred to nitrocellulose for immunoblotting analysis by using a caveolin-1 specific antibody. Molecular weight markers are shown on Left in B and D.