At least four isoforms of troponin T (TnT) exist in the human heart, and they are expressed in
a developmentally regulated manner. To determine whether the different N-terminal
isoforms are functionally distinct with respect to structure, Ca 2+ sensitivity, and inhibition of
force development, the four known human cardiac troponin T isoforms, TnT1 (all exons
present), TnT2 (missing exon 4), TnT3 (missing exon 5), and TnT4 (missing exons 4 and 5),
were expressed, purified, and utilized in skinned fiber studies and in reconstituted …