Channel characteristics of wild-type and mutant TRPV5.

<p>(<b>A</b>) Whole-cell currents in TRPV5-WT (V5-WT) and TRPV5-682P (V5-S682P) injected <i>Xenopus</i> oocytes recorded in response to 300 ms test pulses to various potentials (from −100 to +60 mV in 10 mV increments). Holding potential, 0 mV (N = 5). (<b>B</b>) Mean current-voltage relationships for TRPV5-WT and TRPV5-682P channels (N = 5). These current-voltage relationships are similar to those reported for TRPV5 channels <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0055412#pone.0055412-Cha1" target="_blank">[62]</a>. (<b>C</b>) Mean whole-cell tail currents measured in TRPV5-WT and TRPV5-682P injected <i>Xenopus</i> oocytes during test potentials applied in 10 mV increments from −70 to +40 mV after a pre-pulse to −100 mV in TRPV5-WT and TRPV5-682P channels (N = 5). (<b>D</b>) Time-dependent inhibition of TRPV-WT and TRPV5-682P whole-cell currents. Oocytes were stimulated every 1 s. The peak current amplitude was normalised to that recorded during the first pulse (N = 4). (<b>E</b>) Representative trace of Fura-2 ratio in HEK293 cells transiently transfected with an empty EGFP vector (mock), or EGFP-tagged TRPV5-WT or TRPV5-S682P. Cells expressing EGFP were selected and monitored for changes in intracellular Ca²⁺ levels when extracellular Ca²⁺ concentrations were varied from 1.4 mM Ca²⁺ to 0 mM Ca²⁺ (2 mM EDTA) and 1.4 mM Ca²⁺ which was facilitated by superfusion. (<b>F</b>) Fura-2 levels under resting conditions (t0), minimal Fura-2 ratio after EDTA treatment (tmin) and peak level (tmax) upon administration of 1.4 mM Ca²⁺ after EDTA treatment. Average data of cells transfected with the empty vector (n = 7), TRPV5-wt (n = 24) and TRPV5-S682P (N = 24) from at least three independent experiments. * p<0.05 for TRPV5-WT or TRPV5-S682P versus cells transfected with empty vector. # p<0.05 for TRPV5-S682P versus TRPV5-wt transfected cells.