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Stimulation of Tubulin‐Dependent ATPase Activity in Microtubule Proteins from Porcine Brain by Vinblastin
Author(s) -
Fujii Toshihiro,
Kondo Yoshiyuki,
Kumasaka Michiyo,
Ohki Kosuke
Publication year - 1982
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.1471-4159.1982.tb07991.x
Subject(s) - vinblastine , tubulin , microtubule , podophyllotoxin , stimulation , colchicine , atpase , biochemistry , divalent , chemistry , biology , biophysics , microbiology and biotechnology , enzyme , stereochemistry , neuroscience , genetics , organic chemistry , chemotherapy
Vinblastine, a plant alkaloid which inhibits tubulin polymerization, stimulated an ATPase activity in microtubules. When microtubule proteins were separated into microtubule‐associated proteins (MAPs) and tubulin by phosphocellulose column chromatography, vinblastine did not stimulate an ATPase activity recovered in the MAPs fraction unless tubulin was present. Therefore, vinblastine is considered to act through its binding to the tubulin molecule on MAPs ATPase. Divalent cations that activate tubulin‐dependent MAPs ATPase activity were also required for the stimulation by vinblastine. In the presence of Ca 2+ and vinblastine the ATPase activity was most active and the extent of stimulation reached about 200% of the original level in the absence of vinblastine. Half‐maximal stimulation was attained when the molar ratio of vinblastine to tubulin was 0.5. The concentration of tubulin for half‐maximal stimulation was increased in the presence of vinblastine, while divalent cation requirements were decreased. Several factors such as KC1 (100 mM), alkaline pH (pH 7.5), and low temperature (10°C) were not responsible for the disappearance of the stimulation. Vincristine stimulated tubulin‐dependent MAPs ATPase activity as vinblastine did, whereas the activity was scarcely affected by colchicine, podophyllotoxin, strychnine, and chlor‐promazine. Actin had no effect on MAPs ATPase activity in the absence and presence of vinblastine when it was used in place of tubulin.