Retrograde axonal transport of endogenous proteins in sciatic nerve demonstrated by covalent labeling in vivo.

Extracellularly applied N-succinimidyl [2,3-3H]propionate was used in vivo to covalently label intra-axonal proteins in the rat sciatic nerve. This technique permitted a unique view of axonal transport of proteins independent of biosynthesis. The proteins detected in slow anterograde transport (1 to 2 millimeters per day) correspond to cytoskeletal proteins described in previous papers. The slowly retrogradely transported component (3 to 6 millimeters per day) was composed primarily of a single protein with a molecular weight of 68,000.