Premium
Two Stages in Neurite Formation Distinguished by Differences in Tubulin Metabolism
Author(s) -
Sekimoto Sumito,
Tashiro Tomoko,
Komiya Yoshiaki
Publication year - 1995
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 - 10.1046/j.1471-4159.1995.64010354.x
Subject(s) - neurite , tubulin , microtubule , dorsal root ganglion , metabolism , biochemistry , chemistry , biology , microbiology and biotechnology , biophysics , in vitro , dorsum , anatomy
Changes in tubulin solubility during neurite formation were studied biochemically using rat dorsal root ganglion neurons in culture. When fractionated with Ca 2+ ‐containing buffer at low temperature, a considerable proportion of total cellular tubulin was recovered in the insoluble fraction. We designated this cold/Ca 2+ ‐insoluble tubulin (InsT) and distinguished it from cold/Ca 2+ ‐soluble tubulin (SoIT). From the relative amount of InsT, neurite formation was found to proceed through two distinct stages. The first 6 days after plating (stage 1) in which the proportion of InsT increased dramatically (from 5 to 60%) coincided with neurite outgrowth. In the following period (stage 2), a constant level of InsT was maintained, whereas neurite maturation took place. Pulse‐labeling experiments further revealed that the two stages differed significantly in terms of tubulin metabolism. High rates of synthesis as well as conversion from SoIT to InsT were observed in stage 1, whereas stage 2 was characterized by a decrease in both of these rates and an increase in the rate of degradation. The results show for the first time the coordinated changes in tubulin metabolism that underlie the process of neurite formation.