Figure 2. Effect of Ca²⁺-sensitisers on Ca²⁺ control of motility.

A, B, D, E. Fraction of filaments motile, measured by IVMA is plotted against [Ca²⁺] for representative experiments, details as for Figure 1.

A, D. Effect of Ca²⁺-sensitisers on Ca²⁺-regulation of native thin filaments. Blue, native thin filaments; orange, presence of 30 μM EMD57033; brown, presence of 100 μM Bepridil.

B, E. Effect of Ca²⁺-sensitisers on Ca²⁺-regulation of thin filaments containing the TPM1 E54K DCM-causing mutation. Red, E54K-containing thin filaments; orange, presence of 30 μM EMD57033; brown, presence of 100 μM Bepridil.

C. EMD57033 dose response curve: EC₅₀ was determined at a range of EMD57033 concentrations. The change in EC₅₀ (± SEM of 4 measurements of motility in the same motility chamber) is plotted for three separate experiments.

F. Bepridil dose response curve: motility was measured at a constant 0.037 μM Ca²⁺ with increasing concentrations of Bepridil. The increase in fraction of filaments motile (± SEM of 4 measurements of motility in the same motility chamber) is plotted for three separate experiments and the curve represents the fit of the pooled data to the Hill equation. Values of parameters obtained are shown.