Cell lysates were incubated with rabbit anti-caveolin-1 antibody (1:2000) or mouse anti-EGFP antibody (1:100) at 4°C for 1 h, treated with 20-50 μl protein A-or G microbeads (Miltenyi) at 4°C for 1 h, and processed as described previously [13] . To deplete cholesterol, cell lysates were treated with 10-20 mM MβCD at room temperature for 1 h before co-immunoprecipitation.