S2 domain gives myosin filaments some flexibility

Abstract

JGP microscopy study supports the idea that the region linking myosin head and tail domains can be peeled away from filament backbone to prevent actin-attached heads from impeding filament movement.

(Left to right) Richard Brizendine, Christine Cremo, and Murali Anuganti provide direct evidence that the S2 domain of myosin II is a flexible structure, which would allow it to prevent actin-attached heads from impeding the movement of myosin filaments. Quantum dots labeling a head domain (black) and the filament backbone (red) mostly follow the same trajectory as a filament moves in vitro. But, in rare instances (insets), an actin-attached head briefly lags the backbone’s trajectory before catching up, an event facilitated by the flexibility of the S2 region that connects the motor protein’s head and tail domains.