The role of calcium in platelet microtubule assembly-disassembly
Ikeda, Y.; Kikuchi, M.; Handa, M.; Yoshii, Y.; Toyama, K.; Yamamoto, M.; Watanabe, K.; Ando, Y.
Thrombosis Research 23(1-2): 163-168
1981
ISSN/ISBN: 0049-3848 PMID: 6795754 Document Number: 173435
The role of Ca in the equilibrium between assembled and disassembled microtubules was investigated in human platelets. The 2 pools of microtubule protein were frozen by addition of a glycerol-dimethyl sulfoxide-containing medium and were estimated by measuring the colchicine binding activities of total and polymerized tubulin. Addition of A23187 to platelet rich plasma produced a transient decrease in the pool of polymerized tubulin within 30 s, followed by a return to base-line values within 2 min. Total content of platelet tubulin remained unchanged during the course of aggregation. TMB-8 [8-(N,N-diethylamino)octyl 3,4,5-trimethoxybenzoate], a known intracellular Ca antagonist, abolished this transient decrease in polymerized tubulin induced by A23187, while indomethacin did not. An important role for intracellular Ca in microtubule assembly-disassembly is suggested.