Used as a selective inhibitor of TGF-β-activated kinase 1 (TAK1), ESI-09 is widely applied in cellular signaling research, particularly in studies involving inflammation, apoptosis, and immune responses. It helps modulate pathways linked to NF-κB and MAPK, making it valuable in investigating cancer, autoimmune diseases, and neurodegenerative conditions. Researchers also use ESI-09 to explore the role of TAK1 in insulin signaling and metabolic disorders. Its cell-permeable nature allows for effective in vitro and in vivo experimentation, supporting drug development and mechanistic studies in molecular biology.