Titin acts as a variable stiffness molecular spring that binds calcium and attaches to actin upon activation, explaining residual force enhancement during eccentric muscle contractions.
The structural protein titin likely contributes to active force production during eccentric muscle contractions by binding calcium and attaching to actin, supporting a new three-filament model of muscle contraction.
Eccentric muscle properties are not well characterized by the current paradigm of the molecular mechanism of contraction: the cross-bridge theory. Findings of force contributions by passive structural elements a decade ago paved the way for a new theory. Here, we present experimental evidence and theoretical support for the idea that the structural protein titin contributes to active force production, thereby explaining many of the unresolved properties of eccentric muscle contraction.
Herzog et al. (Thu,) conducted a review in Skeletal muscle contraction. Titin was evaluated. Titin acts as a variable stiffness molecular spring that binds calcium and attaches to actin upon activation, explaining residual force enhancement during eccentric muscle contractions.