1-Naphthyl PP1 hydrochloride is primarily used in biochemical research as a potent and selective inhibitor of Src family kinases. These kinases play a crucial role in cell signaling pathways, and inhibiting them helps researchers study their functions in various cellular processes, including cell growth, differentiation, and survival. This compound is particularly valuable in cancer research, where Src family kinases are often implicated in tumor progression and metastasis. By blocking their activity, scientists can better understand the mechanisms of cancer development and test potential therapeutic strategies. Additionally, it is utilized in studies related to immune cell signaling, as Src kinases are involved in the regulation of immune responses. Its specificity makes it a useful tool for dissecting complex signaling networks in both normal and diseased states.