ERK5-IN-1 is a selective inhibitor of the extracellular signal-regulated kinase 5 (ERK5), a key component in cell signaling pathways involved in proliferation, survival, and differentiation. It is primarily used in research settings to study the role of the ERK5 pathway in cancer, inflammation, and cardiovascular diseases. By blocking ERK5 activation, this compound helps investigate tumor growth mechanisms, especially in breast, prostate, and lung cancers where ERK5 signaling is often overactive. It also supports studies on drug resistance, as inhibition of ERK5 can enhance the effects of other anticancer agents. Additionally, ERK5-IN-1 is used to explore inflammatory responses and endothelial cell function, making it a valuable tool in developing targeted therapies and understanding disease progression at the molecular level.