Figure 1. Aging enhances the constitutive activity of the mTOR pathway in colon smooth muscle. (A) Representative immunoblotts showing expression of mTOR and phosphorylated (active) forms of mTOR, p70S6K1 (at Thr389 and Ser371) and 4E-BP1 in non stimulated muscular layer of colon. Figures in parenthesis are the molecular weight of each band as judged from the molecular weight marker run in each assay. (B) Histogram depicting phosphorylation of mTOR and its substrates in young and aged colon. Values are average ± sem of arbitrary units normalized to mean average values of young colon. * p< 0.05, n = 6.