troponi
Troponi (plural of troponin) refers to a family of regulatory proteins that form the troponin complex on the thin filaments of skeletal and cardiac muscle. The complex consists of three subunits: troponin C (TnC), which binds calcium; troponin I (TnI), which inhibits actin–myosin interaction; and troponin T (TnT), which anchors the complex to tropomyosin. When intracellular calcium rises during excitation-contraction coupling, calcium binds to TnC, triggering a conformational change that moves tropomyosin away from the myosin-binding sites on actin and enables cross-bridge cycling and contraction. Removal of calcium returns troponin to its inhibited state and promotes relaxation.
Troponin isoforms exhibit tissue specificity. Cardiac muscle expresses cardiac troponin I (cTnI) and cardiac troponin T
Clinical relevance is most prominent for the cardiac-specific subunits. Cardiac troponins I and T are released
Notes: in some languages or contexts, troponi may simply refer to troponin proteins in general. In English