Self-assembly pathway of nonsarcomeric myosin II.

Cells need to control the location and timing of actomyosin-dependent force generation, and appear to do so in the first instance by regulating myosin filament self-assembly (Yumura and Fukui, 1985). The mechanism of the self-assembly is little understood. In vitro it is a true self-assembly, which requires a short domain at the C terminus of the myosin molecule. The availability of this domain appears suppressed by the folding of the molecule into a compact, looped state. In vitro, the rate at which these looped molecules unfold turns out to be a key determinant of filament number and filament length.