The effects of coexpressing TRIC-A or TRIC-B with RyR2 on the function of RyR2 channels incorporated into bilayers at 2 μM free Ca ²⁺ . (A) Representative current fluctuations of RyR2 channels from the HEK293 cells expressing RyR2-only (left), RyR2+TRIC-A (middle), and RyR2+TRIC-B (right) at the holding potentials of ±30 mV in symmetrical 210 mM KPIPES, 2 μM free Ca²⁺. The Po (measured over 2 min) is shown above each trace. The zero current level is indicated by C, a single full open channel level by O1, and double full open channel level by O2. The red asterisks highlight subconductance events. (B) Single-channel K⁺ conductance of RyR2 channels from HEK293 cells expressing RyR2-only (black circles), RyR2+TRIC-A (blue squares), and RyR2+TRIC-B (red triangles) in the same solutions as in A. The amplitudes in I–V curve of conductance were measured from multiple traces at ±30 and 0 mV. One-way ANOVA for the independent variable, “type of HEK293 cells,” is not significant with P = 0.72 (n_RyR2 = 10, n_RyR2+TRIC-A = 7, n_RyR2+TRIC-B = 10). Symbols indicate values from individual experiments and bars indicate mean ± SEM.