Anterograde Transport of Vesicles
Figure 10.6 |
Vesicles formed in the cell soma are moved to the site at which they will be used in synaptic transmission. This step in the trafficking of the vesicle is mediated by a process termed fast anterograde axoplasmic transport. As depicted in Figure 10.6, transport is mediated through the interaction of the vesicle with the microtubule. Transport is an energy dependent process in which a so-called motor protein, kinesin, associates with vesicles and moves down the microtubule in a series of attachment-detachment steps. Evidence for the existence of axoplasmic transport comes from a variety of observations, including the movement of radioactive proteins synthesized in the cell soma down the axon to the nerve endings. The speed of transport is 0.5-1.5 cm per hour. Ca2+ is also required for transport. The vinca alkaloid drugs colchicine and vinblastine prevent axoplasmic transport through their disruption of microtubules.
