Vesicle fast axonal transport

Dephosphorylated synapsin inhibits axonal transport of MBOs in isolated axoplasm, while phosphorylated synapsin at similar concentrations has no effect [21]. When a synaptic vesicle passes through a region rich in dephosphorylated synapsin, it may be cross-linked to the available MF matrix by synapsin. Such cross-linked vesicles would be removed from fast axonal transport and are effectively targeted to a synapsin- and MF-rich domain, the presynaptic terminal. 

In neurons and non-neuronal cells, kinesin is associated with a variety of MBOs, ranging from synaptic vesicles to mitochondria to lysosomes. In addition to its role in fast axonal transport and related phenomena in non-neuronal cells, kinesin appears to be involved in constitutive cycling of membranes between the Golgi and endoplasmic reticulum. However, kinesin is not associated with all cellular membranes. For example, the nucleus, membranes of the Golgi complex and the plasma membrane all appear to lack kinesin. Kinesin interactions with membranes are thought to involve the light chains and carboxyl termini of heavy chains. However, neither this selectivity nor the molecular basis for binding of kinesin and other motors to membranes is well understood. 

Schroer, T. A., Brady, S. T. and Kelly, R. Fast axonal transport of foreign vesicles in squid axoplasm. /. Cell Biol. 101 568-572, 1985. 

The interphase organization of microtubules serves many roles, among the most important of which is the rapid transport of organelles and materials packaged in vesicles to various parts of a cell. This process was first observed directly in the giant axons of squid and was therefore named fast axonal transport. In highly elongated... 

In fast axonal transport, dynein motors serve to bring vesicles from near the end of the axon (the plus end of the microtubules) toward the cell body (the minus end of the microtubules). The distance traveled can be as much as a meter. Since dynein is a minus-end directed motor, how does it get out to the plus ends of the microtubules in the first place ... 

Kinesin participates in vesicle transport in a number of cell types, including fast axonal transport in neurons (56). In Sertoli cells, kinesin has been observed to localize to the trans Golgi network, a location suggesting involvement in membrane trafficking within the cell (57). In addition, kinesin is localized to ectoplasmic specializations where it may be involved in the movement and positioning of elongate spermatids within the seminiferous epithelium (55). 

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