Using electrical and optical tweezers to facilitate studies of molecular motors.
Dielectrophoresis was used to stretch and suspend actin filaments across a trench etched between two electrodes patterned on a glass slide. Optical tweezers were used to bring a motor protein-coated bead into close proximity to a pre-selected, suspended actin filament, facilitating the attachment of the myosin-coated bead to the filament. The clearance beneath the filament allowed the bead to move freely along and around its filamentous track, unhindered by solid surfaces. Using defocused images, the three-dimensional position of the bead was tracked as a function of time to obtain its trajectory. Experiments were carried out with myosin V and myosin X. Both motor proteins followed left-handed helical paths with the myosin X motor exhibiting a shorter pitch than the myosin V. The combined use of electrostatic and optical tweezers facilitates the preparation of motility assays with suspended tracks. Variants of this technique will enable higher complexity experiments in vitro to better understand the behavior of motors in cells.
Arsenault
Mark E
ME
Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, Philadelphia, PA 19104-6315, USA.
Sun
Yujie
Y
Bau
Haim H
HH
Goldman
Yale E
YE
D008841:Actin Cytoskeleton / Q000737:chemistry / Q000378:metabolism; D000818:Animals; D002417:Cattle; D004560:Electricity; D004566:Electrodes; D004586:Electrophoresis; D008870:Microtubules / Q000737:chemistry / Q000378:metabolism; D020409:Molecular Motor Proteins / Q000378:metabolism*; D024701:Myosin Type V / Q000378:metabolism; D052898:Optical Tweezers; D011817:Rabbits; D013499:Surface Properties
D020409:Molecular Motor Proteins; D024701:Myosin Type V