YM201636 is a cell-permeable selective inhibitor of the mammalian class III phosphatidylinositol phosphate kinase PIKfyve It functions by targeting and inhibiting PIKfyve enzymatic activity at an IC50 of approximately 33 nM thus reducing the biosynthesis of phosphatidylinositol (3 5)-bisphosphate (PtdIns(3 5)P2) Treatment of various mammalian cell lines (including NIH3T3 MDCK MCF10A COS7 and MEFs) with YM201636 induces the formation of enlarged intracellular vacuoles pointing toward changes in endosomal transport and membrane trafficking Furthermore YM201636 has shown utility in studying insulin-mediated signaling by inhibiting insulin-dependent class I PI3K activation lowering Akt phosphorylation and preventing surface translocation of GLUT4 in adipocytes Researchers frequently utilize this compound to analyze intracellular vesicular transport pathways and phosphoinositide-dependent signaling events