Axonal transport of phospholipid in goldfish optic system
Protein Interaction Maps
After injection of [3H] glycerol into the eye of goldfish, labeled lipid was conveyed by axonal transport in the optic axons to the optic tectum. The transported material was found to consist almost entirely of phosphoglycerides, including both zwitterionic and acidic species. The time course of appearance of the labeled phospholipid in the optic tectum suggested that it might be axonally transported at a rate intermediate between the rates of the fast and slow components in the axonal transport of protein. This possibility, however, was contradicted by the following evidence: a) the rate of transport of the phospholipid that first appeared in the tectum was the same as that of the fast protein component; b) during the first few days after the precursor injection the phase difference between the rates of bulid-up of labeled phospholipid in the optic nerve and tectum such as would be expected with an intermediate rate of transport was not seen; c) the accumulation of phospholipid in the tectum was rapidly terminated after the optic axons were separated from their cell bodies, as would be expected from a fast rather than intermediate transport rate in the isolated axons. The results suggest that the axonal transport of most of the phospholipid had the same rate as the fast component of protein transport, and that the prolonged period of accumulation of the phospholipid in the tectum reflected a prolonged period of release from the cell body into the axon. Only a small proportion of the phospholipid might have been transported at a slower rate. Inhibition of protein synthesis in the retina reduced the amount of transported phospholipid appearing in the tectum almost as much as the transported protein. It is probable, therefore, that the transport of phospholipid occurs in association with protein, possibly in the form of an assembled membrane structure. Whereas the protein that is transported is newly synthesized, the transported lipid need not be. © 1975.
Digital Object Identifier (DOI)
Additional Document Info
has global citation frequency