Figure 4.

Single-channel measurements of RyR1-WT and RyR1-T5001A, E3893Q/E3967Q, and E3893V/E3967V variants. A, single-channel currents were recorded at a holding potential of −20 mV as downward deflections from the closed state (c−) in symmetrical 0.25 m KCl with 2 μm SR luminal Ca²⁺ and the indicated cytosolic Ca²⁺ concentrations. B, Ca²⁺ dependence of RyR1-WT and RyR1-T5001A and -E3893Q/E3967Q variant channel open probabilities. Data are the mean ± S.E. (error bars) of 3–21 recordings.