ITD-1 #28992

ITD-1 is a potent and selective inhibitor of Transforming Growth Factor-β (TGF-β) signaling. This small molecule targets TGF-β receptor II by increasing proteasomal degradation, eliminating the receptor from the cell surface, inhibiting downstream intracellular signaling with an IC₅₀ of 0.85 μM (1). Activation of the TGF-β receptor II leads to phosphorylation of Smad2/3 proteins, transmitting TGF-β signals from the cell surface into the nucleus. ITD-1 inhibits the phosphorylation of Smad2/3 proteins but does not block kinase activity of TGF-β receptors (type I and type II), demonstrating that ITD-1 disrupts TGF-β signaling more selectively than other kinase inhibitors (2).