Fig. 3: Tightening of IP-HD is essential for ATP-induced P2X3 receptor activation.
From: Chronic cough relief by allosteric modulation of P2X3 without taste disturbance
a Zoomed-in view of IP-HD. Mutated residues around IP-HD are indicated with sticks for emphasis. b Homo-oligomers of hP2X3 with double mutations L127C (in the head ___domain of one subunit) and T202C (in the DF ___domain of a neighboring subunit) showed predominantly as trimers in non-reducing Western blots. Cells transfected with WT P2X3 and the cysteine substitution mutants as indicated were lysed in buffers with and without β-ME (1%, 10 mM). Positions corresponding to the sizes of monomeric, dimeric, and trimeric P2X3 subunits are marked with arrowheads, respectively. The experiment was repeated thrice with similar results. c, d Representative currents (c) and pooled data (d) recorded from cells transfected with D158C/E111C (n = 6), L127C/T202C (n = 6), G131C/E111C (n = 6), and wild-type (WT, n = 5) hP2X3 receptors. Cells were clamped at −60 mV and currents were induced by ATP (10 μM) at 7 min intervals. H2O2 (0.3%) and dithiothreitol (DTT, 10 mM) were used to promote and disrupt the disulfide bond, respectively. Data in  d represent the ratio of ATP-evoked current after to before the DTT treatment. Each line represents an independent cell. One sample two-tailed t test against the value 1. Source data are provided as a Source Data file.
