Directional Transport by Nonprocessive Motor Proteins on Fascin-Cross-Linked Actin Arrays

In this study, the unidirectional transport of heavy meromyosin (HMM)-coated beads is demonstrated on fascin-cross-linked actin arrays. The streptavidin-coated surface was properly blocked to prevent nonspecific binding of F-actin and, as a result, a high population of long gelsolin-actin complexes was suspended in the medium for subsequent processes. A flow field was utilized to lay down F-actin aligned along the direction of the flow and fascin cross-linked laid F-actin to prevent F-actin resuspension. When HMM-coated beads came into contact with the fascin-cross-linked actin arrays, they started to move in the same direction over long distances. Because of the nonprocessive nature of myosin II motor protein, the bead size limited the number of HMM heads on the area in contact with F-actin arrays, which resulted in beads traveling at different velocities according to their sizes. Furthermore, this study demonstrates the patterning of actin arrays, which could serve as a basis for the development of applications.