Question

"The neuronal cell bodies (which contain the cell’s nucleus and all organelles) that control movement in the tip of your toe are located at the base of your spine and project very long processes (axons) down your leg before synapsing with the appropriate muscle way down in your toe. This means that the components of the synaptic vesicles, which are made in the neuronal cell body but must act on your toe muscle to affect contraction, must travel a very long distance to reach the neuromuscular synapse. If you analyze the composition of axons histologically, you will find parallel arrays of both intermediate filaments and microtubules. Which cytoskeletal elements, (intermediate filaments or microtubules), do you think are most important in the process of synaptic vesicle movement from the cell body to the tip of the axon? Why?"

Answer 1

The best answer to the question: Which cytoskeletal elements (intermediate filaments or microtubules), do you think are most important in the process of synaptic vesicle movement from the cell body to the tip of the axon? Why? Would be: 1. Microtubules are the more involved of the two types of components of the cytoskeleton on neuronal cells, basically because they are the ones responsible for the regulation of kinesins and their activities and kinesins (one of the types of motor proteins) are the ones that allow SV´s (synaptic vesicles) to move with their cargoes from the AIS (Axon initial segment), along the axon, powered by the action potential, towards the presynaptic terminal, where the cargo will be released through exocytosis.

2. What was mentioned before is the very reason why microtubules would be, of the two, and as far as research has been able to find, the more important of the two constituents of the cytoskeleton. It is important to mention that there is still debate on this, and still research being done because some results point to a more joint work between intermediate filaments and microtubules, depending on the function, location and type of the cargo that is being carried in the vesicles. However, as of now, it is still maintained that at least in transport of vesicles, and ensuring that these reach the axon terminal and can be sent to the motor plate for muscular response, the microtubules play the lead role.