MG-2119（Cat No.:I044425）is a selective small-molecule inhibitor targeting TGF-β receptor I (TGFBR1 or ALK5), a serine/threonine kinase central to the TGF-β signaling pathway. By inhibiting ALK5 kinase activity, MG-2119 blocks phosphorylation of SMAD2/3 and downstream transcriptional responses associated with fibrosis, cancer progression, and immune suppression. It is especially valuable in research on epithelial-to-mesenchymal transition (EMT), tumor microenvironment remodeling, and fibrotic diseases such as idiopathic pulmonary fibrosis and systemic sclerosis. MG-2119 serves as a potent tool for dissecting TGF-β-driven processes and advancing therapeutic strategies targeting this critical signaling axis.