Force generation in striated muscle is primarily controlled by structural changes in the actin-
containing thin filaments triggered by an increase in intracellular calcium concentration.
However, recent studies have elucidated a new class of regulatory mechanisms, based on
the myosin-containing thick filament, that control the strength and speed of contraction by
modulating the availability of myosin motors for the interaction with actin. This review
summarizes the mechanisms of thin and thick filament activation that regulate the …