TGM binding to TβRI and TβRII and competition with TGF-β by ITC.A–E, integrated heats for the injection of TGM-D2 (A), TGM-D12 (B), or TGM-FL (C) into TβRI, and TGM-D3 (D) or TGM-FL (E) into TβRII, together with the fit (smooth line) and residuals (below) to a 1:1 binding model. Error bars indicate bias in the NITPIC estimation of the integrated heats. F and G, TGM-D12 and TGF-β(TβRII)2 competitive binding to TβRI. Integrated heats obtained upon injection of TGF-β(TβRII)2 (F) into TβRI or TGM-D12 into TβRI with a saturating concentration of TGF-β(TβRII)2 binary complex (G). H–J, TGM-D3 and mmTGF-β27Μ competitive binding to TβRII. Integrated heat obtained upon injection of 150 μM mmTGF-β27M into 15 μM TβRII in the sample cell with 0 μM (H), 6.0 μM (I), or 12.0 μM (J) TGM-D3. The data points correspond to the integrated heats and the smooth lines a global fit over the three datasets to a 1:1 binding model with competition. ITC, isothermal titration calorimetry.