Membrane-induced lever arm expansion allows myosin VI to walk with large and variable step sizes.

ABSTRACT: Myosin VI, the only known minus-ended actin filament-dependent motor, plays diverse cellular roles both as a processive motor and as a mechanical anchor. Although myosin VI has a short lever arm containing only one "IQ-motif" and a unique insertion for CaM binding, the motor walks with large and variable step sizes of ∼30-36 nm. Here, we show that the previously predicted coiled-coil domain immediately following the IQ-motifs (referred to as the lever arm extension (LAE)) adopts a stable monomeric, three-helix bundle fold in solution. Importantly, the LAE can undergo reversible, lipid membrane-dependent conformational changes. Upon exposure to lipid membranes, the LAE adopts a partially extended rod shape, and the removal of lipids from the LAE converts it back into the compact helix bundl

SUBMITTER: Yu C 

PROVIDER: S-EPMC3471712 | biostudies-literature | 2012 Oct

REPOSITORIES: biostudies-literature