Cell-permeable. YM-201636 is a selective inhibitor of phosphoinositide kinase (PIK) PIKfyve (IC50 = 33 nM). It inhibits p110α at higher concentration (IC50 = 3 µM). It reversibly impairs endosomal trafficking in NIH3T3 cells, mimicking the effect produced by depleting PIKfyve with siRNA.YM-201636 also blocks retroviral exit by budding from cells.