mTORC1 regulates collagen I expression in lung mesenchymal cells.
A and B, mesenchymal cells derived from fibrotic lung allografts (Fib-MCs) were transfected with Raptor or scrambled siRNA (100 nm) for 48 h followed by protein collection and Western blot analysis. Efficacy of raptor silencing was studied by measuring the effect of the siRNA on Raptor protein expression. Effect of Raptor silencing on phosphorylated S6K1 (Thr-389), 4E-BP1 (Thr-37/46), AKT (Ser-473), and collagen I was measured by Western blot analysis and quantitated (n = 5–10). *, p < 0.05; ***, p < 0.001. C, mesenchymal cells derived from normal lung allografts (non-Fib MCs) were transfected with pRK7-Flag-Rheb followed by protein collection and Western blot analysis at 48 h (n = 5). Representative blots are shown. D, Non-Fib MCs were transfected with TSC2 siRNA and protein expression quantitated at 48 h (n = 5). Representative blots are shown.