YM-254890

YM-254890 is a selective G_αq/11 protein inhibitor isolated from Chromobacterium sp. YM-254890 shows no inhibition of other G protein subtypes. YM-254890 inhibits platelet aggregation induced by ADP by blocking the P2Y₁ signal transduction pathway, with an IC₅₀ value below 0.6 μM^[1][2]. IC50 & Target:G_αq/11 protein^[1][2] In Vitro: YM-254890 inhibits platelet aggregation induced by ADP (2, 5 and 20 μM) in human platelet-rich plasma with IC₅₀ values of 0.37, 0.39 and 0.51 μM. ADP mediates platelet aggregation via two G protein-coupled receptors, P2Y₁ and P2Y₁₂. The effect of YM-254890 on the P2Y₁ and P2Y₁₂ signal transduction pathways using C6-15 cells stably expressing the human P2Y₁ or P2Y₁₂ receptors is examined. Stimulation of P2Y₁-C6-15 cells by 2MeSADP leads to increases in intracellular calcium mobilization. In this assay, YM-254890 inhibits the increase in [Ca²⁺]_i with an IC₅₀ value of 0.031 μM. In contrast, 2MeSADP-induced inhibition of forskolin-stimulated adenylyl cyclase activity in P2Y₁₂-C6-15 cells is unaffected by YM-254890 at 40 μM^[1].