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Two Populations of Axonally Transported Tubulin Differentiated by Their Interactions with Neurofilaments
Author(s) -
Tashiro Tomoko,
Kurokawa Masanori,
Komiya Yoshiaki
Publication year - 1984
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1984.tb05376.x
Subject(s) - neurofilament , tubulin , protein subunit , axoplasmic transport , nap , microtubule , dorsal root ganglion , biology , biophysics , sciatic nerve , chemistry , biochemistry , microbiology and biotechnology , sensory system , anatomy , neuroscience , immunohistochemistry , gene , immunology
In the sensory fibers of the rat sciatic nerve (fibers of the dorsal root ganglion cells), two components of tubulin transport were observed that differed in the rate of transport, solubility in Triton, and subunit composition. The faster component, migrating ahead of the neurofilament proteins, was soluble in 1% Triton. The slower component, migrating with the neurofilament proteins, was insoluble in 1% Triton and contained a unique polypeptide, “NAP,” in the tubulin region that was not present in the faster component. “NAP” was not a subspecies of tubulin as evidenced by peptide mapping. It seems to be a neurofilament‐associated protein. When a complete separation of the main tubulin wave from the neurofilament wave was achieved in the motor axons of the same nerve (axons of the ventral motoneurons) under the effect of ββ‐iminodipropionitrile, a portion of tubulin was still found associated with the retarded neurofilament wave. The subunit composition of this portion was similar to the slower, neurofilament‐associated component in the sensory fibers under normal conditions, i.e., enriched in “NAP” and the most acidic subtype of (β‐tubulin. It is suggested that two populations of transported tubulin exist that are differentiated by the extent of their interaction with neurofilaments.