Troponin T is the tropomyosin-binding subunit of troponin, the thin filament regulatory complex which confers calcium-sensitivity to striated muscle actomyosin ATPase activity. Combinatorial alternative splicing of 5 short exons in the 5' region of this gene may generate up to 32 distinct N-terminal isoforms. These N-terminal isoforms may be further combined with one of two mutually exclusive C-terminal exons (alpha or beta) to produce up to 64 distinct isoforms. For simplicity, only individual splice events are explicitly described here. Increased calcium sensitivity of myofilaments relative to isoform 1. Lacks exon 4. Lacks exon 5. Lacks exon 6. Lacks exon 7. Lacks exon 8. Belongs to the troponin T family.