NCIt definition : Troponin I, troponin T, and troponin C are the three closely associated subunits of
the troponin complex of thin filaments in muscle. The complex serves as a calcium-sensitive
switch that regulates muscle contraction. Troponin T binds tropomyosin to the troponin
complex and inhibits F-actin-myosin interactions. The troponin T gene family comprises
three isoforms: slow skeletal (TNNT1), cardiac (TNNT2) and fast skeletal (TNNT3).
Because it is not normally found in blood, cardiac troponin-T in serum is a sensitive
indicator of myocardial cell injury.;