Cardiomyopathy-Related Mutations in Cardiac Troponin C, L29Q and G159D, Have Divergent Effects on Rat Cardiac Myofiber Contractile Dynamics

Figure 6

Comparison of XB distortion rate constant, c, and tension cost, TC, in detergent-skinned fibers reconstituted with cTnC_WT,cTnC_L29Q, or cTnC_G159D. (a) Effects of RcTnC mutants on c. c was estimated by fitting the R-D model to the force responses from muscle fibers to chirp-length perturbations [35]. (b) Effects of RcTnC mutants on TC. TC was estimated by dividing the maximal ATPase activity with the maximal tension elicited by the muscle fiber. One-way ANOVA was used to compare estimates of 𝑐 and TC in cTnC_L29Q and cTnC_G159D fibers with the data from cTnC_WT fibers as controls. Values are reported as mean ± SEM. Number of fibers tested in each group is as follows: cTnC_WT,𝑛=15;cTnC_L29Q,𝑛=10;cTnC_G159D,𝑛=14. Minimal statistical significance was set at 𝛼=0.05, **𝑃<0.01.

(a)

(b)