In striated muscle the force generating acto-myosin interaction is sterically regulated by the
thin filament proteins tropomyosin and troponin (Tn), with the position of tropomyosin
modulated by calcium binding to troponin. Troponin itself consists of three subunits, TnI,
TnC, and TnT, widely characterized as being responsible for separate aspects of the
regulatory process. TnI, the inhibitory unit is released from actin upon calcium binding to
TnC, while TnT performs a structural role forming a globular head region with the regulatory …