text: Motor proteins utilizing the cytoskeleton for movement fall into two categories based on their substrate: microfilaments or microtubules. Actin motors such as myosin move along microfilaments through interaction with actin, and microtubule motors such as dynein and kinesin move along microtubules through interaction with tubulin. 
  There are two basic types of microtubule motors: plus-end motors and minus-end motors, depending on the direction in which they "walk" along the microtubule cables within the cell.