Figure 1.

Motility chamber and experimental design. The movement of fluorescent endocytic vesicles and microtubules was monitored with an inverted microscope with the use of a motility chamber (A) constructed with double-stick tape sandwiched between a large coverslip and glass cut from a microscope slide. In the gliding assay, motor protein is perfused into the chamber, followed by microtubules, which bind to the motor proteins. Microtubule movement was observed after ATP addition. In the vesicle motility assay (B), motor protein is perfused into the chamber, followed by microtubules, followed by vesicles. The vesicles bind microtubules and are assayed for motility upon addition of ATP.