RN486 is a potent and selective inhibitor of Bruton's tyrosine kinase (BTK), an enzyme involved in B-cell receptor signaling. It is primarily used in research settings to study B-cell activation and proliferation, particularly in the context of autoimmune diseases and B-cell malignancies. By inhibiting BTK, RN486 effectively blocks downstream signaling pathways that lead to B-cell survival and antibody production, making it a valuable tool for investigating conditions such as rheumatoid arthritis, lupus, and certain leukemias and lymphomas. Its high selectivity allows researchers to dissect BTK-specific effects without significant off-target interference, supporting its use in preclinical studies aimed at validating BTK as a therapeutic target.