Ion permeation pathway within the internal pore of P2X receptor channels
- Molecular Physiology and Biophysics Section, Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, United States
- Department of Biology, Johns Hopkins University, United States
Figures
Figure 1
The cytoplasmic cap in P2X3 receptor channels.
(A) Side view of the structure of hP2X3Slow with ATP bound (PDB ID: 6ah4). Ribbon representations of each subunit are colored blue, pink, and green, with a HOLE representation along the central axis …
Figure 2 with 2 supplements
Conservation of residues in the cytoplasmic cap in P2X receptor channels.
(A) Intracellular view and (B) side view of the cytoplasmic cap from hP2X3Slow in complex with ATP (PDB ID: 6ah4) using ribbon representations. (C) Intracellular view and (D) side view showing a …
Figure 2—figure supplement 1
Conservation of the cytoplasmic cap in P2X receptor channels.
(A) Multiple sequence alignment of all human, rat, and mouse P2X subtypes, truncated to show residues that contribute to the cytoplasmic cap in available structures of human P2X3 and rat P2X7. …
Figure 2—figure supplement 2
Multiple sequence alignment of human, rat, and mouse P2X receptor channels.
Multiple sequence alignments obtained using TCoffeeWS via Jalview with residues are colored using Jalview’s ClustalX color scheme, which is based on side chain character and conservation at that …
Figure 3 with 1 supplement
Accessibility of E17C in rP2X2–3 T to extracellular 2-trimethylaminoethyl methanethiosulfonate (MTSET).
(A) Testing for modification of rP2X2–3 T by extracellular MTSET after opening channels with extracellular ATP. Consecutive current traces elicited by extracellular ATP application at -60 mV without …
Figure 3—figure supplement 1
Concentration-dependence for activation of rP2X2 constructs.
Normalized concentration-dependence for ATP activation of rP2X2–3 T (black filled circles, n=7), E17C rP2X2–3 T (purple filled circles, n=3), and WT rP2X2 (gray open circles, n=4) in solutions …
Figure 4
Accessibility of E17C in rP2X2–3 T to extracellular 2-aminoethyl methanethiosulfonate (MTSEA).
(A) Testing for modification of rP2X2–3 T by extracellular MTSEA after opening channels with extracellular ATP. Consecutive current traces elicited by extracellular ATP application at -60 mV without …
Figure 5
Rates of methanethiosulfonate (MTS) modification in rP2X2 for E17C and comparison with rates for the pore-lining TM2 helix.
(A) Fit of a single exponential function (purple relation) to the time course of current inhibition by 2-trimethylaminoethyl methanethiosulfonate (MTSET) (1 mM) for E17C rP2X2–3 T in the presence of …
Figure 6
Ion selectivity of rP2X2 and influence of the E17K mutation.
(A) Representative I-V relationships for WT rP2X2 obtained from the same cell using 0.5 s voltage ramps from –60 mV to +60 mV from a holding potential of –60 mV in symmetric 140 mM NaCl solution …
Figure 7
Expression and characterization of mP2X5.
(A) mP2X5 sensitization upon initial exposure to a sustained external application of ATP (3 µM). Subsequent short ATP applications activate slowly desensitizing currents of similar amplitude …
Figure 8
Ion selectivity of mP2X5 and influence of K17E and K17D mutations.
(A) Representative I-V relationships for WT mP2X5 obtained from the same cell using 0.5 s voltage ramps from –60 mV to +60 mV from a holding potential of –60 mV in symmetric 140 mM NaCl solution …
