Probing the Mechanism of Kinesin-1 Motion in Three Dimensions Using the Photonic Force Microscope

Abstract

Kinesin-1 is a molecular motor essential for cellular function. It transports components around the cell by a processive movement along microtubules while hydrolysing ATP. Although extensively studied by a variety of techniques, the mechanism used by these single-molecule motors to produce this efficient motion on the nanometer scale is not fully understood.In our investigations we use the Photonic Force Microscope (PFM) to trap and track a 500nm bead attached to a kinesin motor as it interacts with a microtubule in vitro. The PFM is an optical trap capable of recording a trapped dielectric particle's motion in three dimensions with nanometre spatial and microsecond temporal resolutions. Using the data recorded we can infer information about the molecular motor's position and its mechanical properties. By characterising different conformational states of the kinesin molecule from its changing mechanical properties as it processes, we expect to learn more about the cycle of events that make kinesin movement possible.An understanding of how nature achieves this motion on the nanoscale will help combat diseases related to kinesin's malfunction and will allow production of similar artificial nanomachines in the future.View Large Image | View Hi-Res Image | Download PowerPoint Slide