The diffusive interaction of microtubule binding proteins.

Microtubule-based motility is often thought of as specifically referring to the directed stepping of microtubule-based motors such as kinesin or dynein. However, microtubule lattice diffusion (also known as diffusional motility) provides a second mode of transport that is shared by a much broader class of microtubule binding proteins. Microtubule lattice diffusion offers distinct advantages as a transport mechanism including speed, bidirectional microtubule end targeting, and no requirement for direct chemical energy (i.e. ATP). It remains to be seen whether a universal binding mechanism for this interaction will be identified but electrostatic interactions appear to play a significant role. In the meantime, the well-studied subject of DNA binding proteins that diffuse along the DNA backbone provides an insightful analog for understanding the nature of microtubule-based diffusional motility.