Tyrphostin AG 879 is primarily used as a selective inhibitor of receptor tyrosine kinases, particularly targeting the TrkA and insulin receptor kinases. It is widely applied in research settings to study signal transduction pathways involved in cell growth, differentiation, and survival. Due to its ability to block neurotrophin signaling through TrkA inhibition, it is used in neuroscience research to investigate neuronal development and neurodegenerative conditions. It has also been employed in cancer studies, where it helps probe the role of tyrosine kinase activity in tumor cell proliferation and apoptosis. Additionally, AG 879 is used to explore insulin signaling mechanisms and insulin resistance in cellular models, making it a valuable tool in metabolic disease research.