Western blot analysis of extracts from HaCaT cells, untreated (-) or treated with hTGF-β3 #8425 and hTGF-β1 #8915 (100 ng/ml, 30 min; +) in the absence or presence of the TGFR inhibitor ITD-1 (5 μM, 18 hr; +), using Phospho-Smad2 (Ser465/467)/Smad3 (Ser423/425) (D27F4) Rabbit mAb #8828 (upper) or Smad2/3 (D7G7) XP® Rabbit mAb #8685 (lower).
Chemical structure of ITD-1.
ITD-1 is supplied as a lyophilized powder. For a 10 mM stock, reconstitute 5 mg of powder in 1.2 ml of DMSO. Working concentrations and length of treatment can vary depending on the desired effect.
Store lyophilized at -20ºC, desiccated. In lyophilized form, the chemical is stable for 24 months. Once in solution, store at -20ºC and use within 3 months to prevent loss of potency. Aliquot to avoid multiple freeze/thaw cycles.
Molecular Weight: 415.5 g/mol
Molecular Formula: C27H29NO3
Solubility: Soluble in DMSO at 8 mg/ml or ethanol at 4 mg/ml with slight warming.
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).
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