Used primarily in research settings to inhibit the activity of the TGF-β (transforming growth factor-beta) receptor, specifically targeting ALK5 (activin receptor-like kinase 5). This inhibition helps in studying signaling pathways involved in fibrosis, cancer progression, and immune regulation. Commonly applied in cellular and animal models to evaluate the therapeutic potential of blocking TGF-β signaling, particularly in diseases such as pulmonary fibrosis, renal fibrosis, and certain tumors. Its selectivity makes it a valuable tool for distinguishing ALK5-dependent effects from other kinase-mediated responses in experimental biology.