Fig. 4. Stimulation with both insulin and isoproterenol results in an increased association of ß2AR with actin and tubulin. (A) Wild-type A431 cells were stimulated with either insulin or isoproterenol for 30 minutes. Cell lysates were immunoprecipitated using ß2AR-specific antibodies. Immunoprecipitated proteins were subjected to SDS-PAGE and immunoblotted with anti-tubulin, anti-actin or anti-ß2AR antibodies. Western blots show the increased density of bands corresponding to actin and tubulin. Bands, detected by ß2AR-antibodies, confirmed the equal loading of the samples. (B) Quantification of actin and tubulin detection in precipitates: data from western blots (as in A) were quantified by measuring area density (Adobe PhotoShop). The graphs show that the association of ß2AR with actin and tubulin is much greater in stimulated cells than that in unstimulated cells.