Skip to content

Anne-Marie Lauzon Videos

Videos of motility and laser trap experiments
Data collected by Genevieve Bates, Horia Nicolae Roman, Nigel John Fairbank, Paul-André Risse.

video of in vitro motility assayVideo 1: In vitro motility assay: Consists in observing fluorescently labeled actin filaments as they get propelled by myosin molecules adhered randomly to a nitrocellulose-coated coverslip. The velocity of actin filament propulsion is determined in presence of MgATP. (TRITC-labeled skeletal muscle actin filaments propelled by smooth muscle myosin). (QuickTime)

video of in vitro motility assay: skeletal muscleVideo 2: In vitro motility assay: TRITC-labeled skeletal muscle actin filaments decorated with tropomyosin-a and -b and propelled by smooth muscle myosin. (QuickTime)

Video 3: a-actinin force assay (QuickTime): This assay uses a-actinin to attach actin to the nitrocellulose on the coverslip and retard the propulsion by myosin. The greater the concentration of a-actinin needed to stop the movement of actin, the stronger the force generated by the actomyosin complex. (QuickTime)

video of alpha actinin force assay: normal actin movementVideo 3a: Low [a-actinin] normal actin movement (QuickTime)

video of alpha actinin force assay: slower actin movementVideo 3b: Average [a-actinin] slower actin movement (QuickTime)

vido of alpha actinin force assay: no actin movementVideo 3c: High [a-actinin]: no actin movement (QuickTime)

video of laser trap unbinding assayVideo 4: Laser trap unbinding assay (QuickTime): A single beam laser trap is used to capture a 3µm diameter bead coated with NEM-myosin (small bead in video). A TRITC-labeled actin filament is attached to the bead and brought in contact with myosin randomly adhered to a 4.5µm pedestal (large bead in video) on a coverslip. After allowing time for binding of myosin to actin, the pedestal is moved away from the trap at constant velocity. Initially, the trapped bead follows the pedestal, offset from the centre of the trap. When the pulling force exerted by the trap exceeds the binding force of the myosin molecules, the microsphere springs back into the trap centre, its unloaded position. The force of unbinding is equal to the product of the maximal distance between the bead and the trap centre by the trap stiffness. (QuickTime)

laser trap video assayVideo 5: A suspended Human Peripheral Blood Mononuclear Cell (HPBMC) being moved with a laser-trap to the surface of an adherent Human Bronchial Smooth Muscle Cell (HBSMC. HBSMCs were cultured on glass coverslips and a suspension of freshly-isolated HPBMCs was added. One HPBMC was trapped using a single-beam laser-trap and brought into contact with a spindle-shaped HBSMC, which comes into focus at the end of the movie. (Windows Media Player)