cTnI-MD truncations affected the tension-pCa relationship differently at long vs. short SL. Developed tension-pCa relationships for A) cTnI(WT) (●) and (○) at 2.2 and 1.9µm SLs, respectively; B) cTnI(1–167) (▼) and (▽) at 2.2 and 1.9µm SLs, respectively; and C) cTnI(1–193) (▲) and (∆) at 2.2 and 1.9µm SLs, respectively. Lines represent 3-parameter Hill fits to the tension-pCa data, with the fine dashed line representing cTnI(WT) fit at 1.9µm SL, and bold dashed line for cTnI(WT) fit at 2.2µm SL replotted in panel B and C.
*: SL effect for cTnI(WT); P < 0.05
†: Truncation effect compared to cTnI(WT) at same SL; P < 0.05