Observation of Microtubule-Based Motor Protein Activity

Abstract

It is possible to detect the presence of motor proteins that have the ability to translocate particles along microtubules. The two procedures described here were developed to detect microtubule-dependent motor protein activity in cell lysates or of purified proteins. In the first procedure, latex beads bound to the putative motor protein are assayed for their ability to translocate along microtubules in an ATP-dependent fashion. If motor protein activity is present, it will bind to the beads and translocate them unidirectionally along the microtubules. In the second procedure, motor proteins induce microtubule gliding over a glass coverslip surface that is coated with active motor protein. Because the mass of a microtubule is negligible compared to that of a coverslip or slide, the microtubule glides over the glass surface when the surface is coated with active motor protein. Also included here are descriptions of assays designed to determine the directionality of movement of microtubule-based motor proteins.