Subsets of axonally transported and periaxonal polypeptides are released from regenerating nerve

Using two-dimensional polyacrylamide gel electrophoresis to analyze proteins, we have found subsets of periaxonal and fast-transported axoplasmic proteins that are released in vitro from regenerating sciatic nerve into a surrounding bath. Of the fast-transported proteins that are released from nerve, there is a subset of at least five polypeptides that appears in greater relative abundance in the bath than in the nerve. Some of these released, fast-transported proteins are glycosylated. Several periaxonally synthesized polypeptides are released in significantly greater amounts from regenerating nerve, and of these polypeptides, two are released in greater amounts from nerve only at regions of regeneration or distal to regeneration. These released polypeptides do not represent the most abundant of the locally synthesized proteins. The released, fast-transported and periaxonal proteins may play a role in intercellular signaling or in modulation of the extracellular environment during nerve regeneration.