Comparison of proteins transported in different tracts of the central nervous system

Reversal of axonal transport of endogenous labeled protein was studied in intact and injured nerve axons. Nerve crushes were used to collect labeled protein transported in anterograde and retrograde directions in rat sciatic nerve motoneuron axons after administration of L-[35S]methionine to the vicinity of the cell bodies. The collected proteins were characterized by sodium dodecyl sulfate polyacrylamide gel electrophoresis and subsequent fluorography. In injured nerves, where the nerves were ligated distally at the time of precursor injection, the polypeptide composition of proteins moving in anterograde and retrograde directions, 9-11 h after precursor injection, was identical, indicating that reversal at a ligature is a nonselective process. In intact nerves, protein moving in the anterograde direction 22-24 h after injection was different from that found 9-11 h after injection, and was also different from protein moving in the retrograde direction 22-24 h after injection. However, protein moving in the retrograde direction 22-24 h after injection was similar to protein moving in the anterograde direction 9-11 h after injection. Thus it appears that the same group of proteins originally transported into the axon are later returned toward the cell body. In intact axons, also, reversal was nonselective, except that one major labeled polypeptide was reduced in amount in the protein moving in the retrograde direction.

Section: A Blsbysupporting

confidence: 90%

Reversal of Axonal Transport: Similarity of Proteins Transported in Anterograde and Retrograde Directions

Bisby

1981

“…The limited number of later time points we studied leaves open the possibility that some of the late arriving glycoprotein is indeed transported at some intermediate rate (slower than the 300-400 mm/day rate of the initially arriving glycoprotein). In connection with this, we note that one-dimensional slab gels of [35S]methionine-labeled transported proteins easily resolve protein composition differences characteristic of the arrival of several intermediate rates of transport (Willard et al, 1974;Padilla et al, 1979). With the same methodology using [3H]fucose, however, we were unable routinely to detect glycoprotein bands characteristic of late-arriving material that would have been indicative of an intermediate FIG.…”

Section: Waves Of Fucosylated Glycoprotein Transportmentioning

confidence: 94%

“…It is known that the amino acid labeled, axonally transported proteins in retinal ganglion cells are very similar to those in other CNS tracts of the rat (Padilla et al, 1979;Padilla and Morell, 1980~). We have also reported that fucosylated transported glycoproteins are very similar in the geniculocortical and hippocampal commissural pathways of the rat J .…”

Section: Fucosylated Glycoproteins Transported In Different Tracts Ofmentioning

confidence: 96%

Axonal Transport, Deposition, and Metabolic Turnover of Glycoproteins in the Rat Optic Pathway

Goodrum

Morell

1982

Self Cite

Following intraocular injection of [3H]fucose in the rat, radioactive glycoproteins are rapidly transported to the nerve terminals in at least two waves, one with a peak at 8 h and a second with a peak at about a week. The molecular weight distribution of radioactive peptides in ach transport wave as determined by gel electrophoresis in buffers containing sodium dodecyl sulfate is very similar. Most of the many glycopeptides in the first wave of rapid transport pass through the optic tract in unison (apparent half‐life of about 15 h) and are preferentially destined for the nerve endings. However, two proteins of apparent M. W. 28,000 and 49,000 are preferentially retained in the axons. The remaining proteins, after reaching the nerve endings (superior colliculus), decay with apparent half‐lives ranging from 17 to 34 h. During the second wave a large amount of the 28,000 and 49,000 M. W. peptides are again preferentially retained in the axons. The remaining proteins, on reaching the nerve endings, decay with apparent half‐lives ranging from 5 to 9 days. Subcellular fractionation of the superior colliculus supports the hypothesis that the 49,000 and 28,000 M. W. peptides are the predominantly labeled glycoproteins present in myelinated axons (representing over 50% of the radioactive glycoproteins 7 days following injection), although they are probably also present in membranes of the nerve endings. A comparison with glycoprotein transport in other tracts (geniculocortical and nigrostriatal tracts) suggests that glycoprotein transport in these pathways has many similarities to glycoprotein transport in the retinal ganglion cells, and that the optic system is a good general model for axonal transport in the CNS.

“…Previous studies in which radioactive rapidly transported proteins were separated by polyacrylamide gel electrophoresis have revealed that, within a given species, the patterns of labeled proteins are remarkably similar in functionally different types of neurons (Barker et al, 1975;1977;Bisby, 1977;Padilla et al, 1979;Stone and Wilson, 1979), and differences, when detected, have only involved the relative amounts of the same proteins or have been restricted to only a few proteins (Black and Lasek, 1978). Since the rapidly transported proteins are mainly associated with membranes (Schwartz, 1979;Grafstein and Forman, 1980), this implies that many of the major membrane proteins are similar in different types of neurons.…”

Section: Discussionmentioning

confidence: 99%

“…Both single and two-dimensional methods have indicated that these populations are very heterogeneous, and span a wide range of molecular weights and isoelectric points. However, remarkable consistency has been found in the electrophoretic profile of the major rapidly transported axonal proteins in functionally different neurons (Barker et al, 1975;1977;Bisby, 1977;Black and Lasek, 1978;Padilla et al, 1979;Stone and Wilson, 1979) and within similar nerve cells in divergent physiologic states (Theiler and McClure, 1977;Bisby, 1980). These studies also suggested that the electrophoretic profiles of rapidly transported protein might be similar in the axons from different species (Barker et al, 1975;Bisby, 1977), but variations in the electrophoretic methods made a rigorous comparison of these data difficult.…”

mentioning

confidence: 99%

Comparative Analysis of Rapidly Transported Axonal Proteins in Sensory Neurons of the Frog and Rat

Neale

Formant

Shibla

et al. 1980

35S-labeled proteins carried by fast axonal transport in sciatic sensory axons of bullfrog and rat were separated electrophoretically on discontinuous polyacrylamide gradient slab gels. In contrast to the previously reported similarity in the electrophoretic profiles of rapidly transported proteins from functionally different neurons, we have found that there is very little correspondence in the profiles of these proteins in functionally similar neurons from two widely studied species. We also found very little correspondence between the two species in the profiles of locally synthesized sciatic nerve protein. The results demonstrate the difficulty inherent in comparing the electrophoretic profiles obtained using these two model systems for the study of rapidly transported axonal proteins. In particular, relationships between the major rapidly transported proteins in the two species could not be analyzed with this technique.