FIG. 7.

Inhibition of the p70S6 kinase pathway leads to increased association of IRS-2 and p85. (A) MDA-MB-468 cells were treated with either DMSO or 50 nM rapamycin for 3 h, and cell lysates were collected. Total cell lysates were subjected to immunoblot analysis with antibodies to IRS-2, phospho-p70S6 kinase, and tubulin. (B) MDA-MB-468 cells growing in medium with 10% FBS or in serum-free medium supplemented with 100 ng of insulin/ml (24 h) were treated with DMSO (D) or 50 nM rapamycin (R). Cell lysates were collected after 3 h of treatment and immunoprecipitated with p85 antibody. Immunocomplexes were subjected to immunoblot analysis with IRS-2 and p85 antibodies. IP, immunoprecipitation; IB, immunoblot.