An axonal winch

Mitochondria and other cellular subunits are transported from the cell body of neurons toward the growth cone of axons via kinesin-based fast transport. On page 373, Miller and Sheetz show that mitochondria also move down the distal portion of the axon via a low-velocity transport mechanism.

Numerous models have been proposed for how axons grow, with a general consensus that the axon cytoskeleton is stationary and growth occurs at the distal tip. In the current study, Miller and Sheetz labeled mitochondria of chicken dorsal root ganglion neurons and followed their movement along the length of the axon. As expected, the mitochondria moved along the cytoskeleton at a rate consistent with kinesin-based transport. Additionally, a subset of mitochondria appeared to dock on the cytoskeleton and then move distally at a substantially slower...