Fig. 1. Expression of caveolin and GM1 in HeLa and CaCo-2 cells. (A) Lysates of CaCo-2 and HeLa cells were separated by 12% SDS-PAGE and subjected to immunoblotting with polyclonal caveolin and ß-actin antibodies. Caveolin expression was detected in HeLa cells using short (S) exposures but not in CaCo-2 cells even upon long (L) exposure of the film. (B) To detect ganglioside GM1, 2, 5 and 10 µg of total protein (in 2 µl) from lysates of HeLa and CaCo-2 cells were dot blotted onto nitrocellulose filter strips and then incubated with HRP-conjugated CTX B subunit and revealed by chemiluminescence. (C) Triton X-100 (TX-100) soluble (supernatant) and insoluble (pellet) fractions were prepared and caveolin was found to be present in the insoluble fraction of HeLa cells. (D) Dot blot analysis with HRP-CTX of dilutions of the TX-100 soluble (supernatant) and insoluble (pellet) fractions showed that ganglioside GM1 was found to be present in the TX-100 insoluble fraction in both HeLa and CaCo-2 cells.