Figure 2.

TGFβ-stimulated PDGFRβ activates Akt signaling. A and D, TGFβ increases phosphorylation of PDGFRβ at the PI 3-kinase binding site Tyr-751 to increase Akt phosphorylation. Mesangial cells were incubated with 2 ng/ml TGFβ for the indicated duration. The cleared cell lysates were immunoblotted with indicated antibodies. B, C, and E–H, mesangial cells were treated with 5 µm SB (panel B) or 0.1 µm JNJ (panels C, E, and F) or transfected with siRNAs against PDGFRβ or scrambled RNA (panels G and H) prior to incubation with 2 ng/ml TGFβ for 2 h. The cell lysates were immunoblotted against the indicated antibodies. Molecular weight markers are shown in the left margins.