Troponin is a component of thin filaments (along with actin and tropomyosin), and is the protein to which calcium binds to accomplish this regulation. Troponin has three subunits, TnC, TnI, and TnT. When calcium is bound to specific sites on TnC, tropomyosin rolls out of the way of the actin filament active sites, so that myosin can attach to the thin filament and produce force and/or movement. In the absence of calcium, tropomyosin interferes with this action of myosin, and therefore muscles remain relaxed.

Troponin T is a part of the troponin complex. It binds to tropomyosin, interlocking them to form a troponin-tropomyosin complex. The tissue specific subtypes are:Slow skeletal troponin T1, TNNT1; Cardiac troponin T2, TNNT2 ;Fast skeletal troponin T3, TNNT3. Troponin T binds to tropomyosin and helps position it on actin . And in a less complicated light, Troponin T modulates contraction of striated muscle.