P2X C-terminal peptides compete with P2X channels for binding to intracellular PIP_n.

<p>A) Representative traces of patch-clamp recordings showing that intracellular injection of the P2X4 C-terminal (-CT) peptide leads to a rundown of the P2X4 current in HEK293 cells by competing for intracellular PIP_n. B) Intracellular injection of the P2X5-CT peptide does not affect the P2X4 current phenotype. C) Effect on P2X4 current amplitude of injection of peptides from the P2X4 WT, P2X4 K362Q-K363Q (2M), P2X5 WT or P2X5 S365K-E366Y-E374K (3M) C-terminus. D) Competition for PIP_n binding from P2X4-CT or P2X5-3M-CT peptide injection leads to a slower desensitization of the P2X4 current. Values were normalized to the initial recording value obtained immediately after whole-cell configuration was obtained (n = 4–5; *, p<0.05; **, p<0.01; ***, p<0.001, each group compared to control).