Figure 11.

PDGFRβ-stimulated mTORC1 regulates TGFβ-induced protein synthesis, hypertrophy, and matrix proteins fibronectin and collagen I (α2) expression. Mesangial cells were transfected with siRNAs against PDGFRβ or scrambled RNA along with Myc-tagged raptor expression vector as indicated. Transfected cells were incubated with 2 ng/ml TGFβ. In panels A and B, respectively, protein synthesis and hypertrophy of mesangial cells were measured as described in the experimental procedures. Mean ± S.D. of triplicate measurements is shown. *p < 0.008 (panel A) and *p < 0.0001 (panel B) versus control; **p < 0.013 (panel A) and **p < 0.002 (panel B) versus TGFβ; #p < 0.005 (panels A) and #p < 0.004 (panel B) versus TGFβ + siPDGFRβ. In panels C and D, the cleared cell lysates were immunoblotted with the indicated antibodies.