Figure 5.

ATP-induced Ca²⁺ influx through P2X₃ receptors activates downstream signaling molecules. (A) Representative blots showed a time-dependent ERK phosphorylation (pERK) in HEK293 cells expressing P2X₃-Myc-GFP by α, β-MeATP. Total ERK served as a loading control. (B) α, β-MeATP-induced ERK phosphorylation was inhibited by A-317491. (C) α, β-MeATP failed to induce ERK phosphorylation in HEK293 cells expressing P2X₃^K299A-Myc-GFP. (D) This ERK phosphorylation was also abolished by extracellular Ca²⁺ depletion (Ca²⁺-free) or BIM, FTI-277 or U-0126, but not H-89. (E, F) Representative blots showed a time-dependent H-Ras activation in HEK293 cells expressing P2X₃-Myc-GFP by α, β-MeATP that was abolished by A-317491. Total H-Ras served as a loading control. (G) BIM pre-treatment also abolished the α, β-MeATP-induced H-Ras activation.