Fig. 9. Association of SR-BI with caveolin-1 in intestinal epithelial cells. Homogenates of epithelial cells (detached from the duodenum) and Caco-2 cells were incubated with anti-SR-BI (a-SR-BI) antibody. The immunoprecipitates were run on SDS-PAGE and transferred to a nitrocellulose membrane. The membrane was blotted with anti-SR-BI (a-SR-BI) or anti-caveolin-1 (a-cav-1) antibodies. Immunoblotting with a-SR-BI revealed the SR-BI protein, whereas immunoblotting with a-cav-1 did not display any signal. The lack of co-precipitation and the absence of caveolin-1 signal refuted the presence of caveolin-1 and potential physical interaction between SR-BI and caveolin-1. STD, standard.