Fig. 4.

Effect of the different HCM-causing TnT mutations on Ca²⁺-sensitivity and its modulation by TnI phosphorylation. Summary of the HCM-causing TnT mutations. Mean EC₅₀ values from replicate paired experiments are plotted, see Table 3. Error bars are ± SEM. Blue, WT thin filaments; Blue hatched, unphosphorylated WT thin filaments; Purple, HCM-causing TnT mutant thin filaments; Purple hatched, unphosphorylated mutant thin filaments. The previously studied ACTC E99K and TPM1 E180G were included as a comparison. A. All the HCM-causing TnT mutants show increased Ca²⁺-sensitivity (decreased EC₅₀) compared to WT thin filaments. B. All the HCM-causing TnT mutants are uncoupled in comparison to WT thin filaments.