YM-201636

YM-201636 is a potent and selective PIKfyve inhibitor with an IC₅₀ of 33 nM. YM-201636 also inhibits p110α with an IC₅₀ of 3.3 μM. YM-201636 inhibits retroviral replication. IC50 & Target: IC50: 33 nM (PIKfyve), 3.3 μM (p110α)^[1] In Vitro: Acute treatment of cells with YM-201636 shows that the PIKfyve pathway is involved in the sorting of endosomal transport, with inhibition leading to the accumulation of a late endosomal compartment and blockade of retroviral exit. The yeast orthologue of PIKfyve, Fab1, is found to be insensitive to YM-201636 (IC₅₀>5 μM). YM-201636 does not inhibit a type IIγ PtdInsP kinase even at 10 μM and inhibits a mouse type Iα PtdInsP kinase with an IC₅₀>2 μM^[1]. YM-201636 almost completely inhibits basal and insulin-activated 2-deoxyglucose uptake at doses as low as 160 nM, with IC₅₀=54 nM for the net insulin response. YM-201636 also completely inhibits insulin-dependent activation of class IA PI 3-kinase^[2]. At low doses (10-25 nM), YM-201636 inhibits preferentially PtdIns5P rather than PtdIns(3,5)P2 production, whereas at higher doses, the two products are similarly inhibited. YM-201636 at 160 nM inhibits PtdIns5P synthesis twice more effectively compared with PtdIns(3,5)P2 synthesis^[3]. MDCK cells treated with YM-201636 accumulate the tight junction protein claudin-1 intracellularly. YM-201636 treatment blocks the continuous recycling of claudin-1/claudin-2 and delays epithelial barrier formation^[4].