NBME Histology Practice Test

The main idea here is how motor proteins drive directional transport along microtubules in neurons. Microtubules in axons are polarized with plus ends facing the axon terminal, so the motor that moves toward the plus end carries cargo forward, toward the terminal, along those tracks.

Kinesin is the plus-end–directed motor that walks along microtubules to the axon terminal, delivering vesicles and organelles outward. Dynein, in contrast, moves toward the minus end, bringing cargo back toward the cell body (retrograde transport). Myosin uses actin filaments for movement, typically over short distances near the membrane or cortex, not along microtubules. Actin is a filament, not a motor protein.

So the motor protein that moves cargo toward the axon terminal along microtubules is kinesin.