Biological Activity: 
ITD-1 is a novel and highly selective TGFβ pathway inhibitor identified by a high throughput, embryonic stem cell (ESC) cardiac differentiation screening. ITD-1 promoted cardiomyocyte differentiation specifically via degradation of the TGFβ type II receptor (TGFBR2), effectively clearing the receptor from the cell surface and selectively inhibiting intracellular signaling (IC₅₀ 0.4–0.8 µM), revealing a role for TGFβ signaling mechanism as a repressor of cardiomyocyte fate. ITD-1 selectively enhanced the differentiation of uncommitted mesoderm to cardiomyocytes, but not to vascular smooth muscle and endothelial cells. In contrast to other commonly used TGFβ receptor (ALK) inhibitors, ITD-1 importantly only inhibits TGFβ signaling, but does not block the closely related Activin A signaling pathway, and represents a unique reagent for exploring TGFβ function in various biological contexts such as embryonic development and models of disease.