Microtubule protein preparations from C6 glial cells and their spontaneous polymer formation.

Abstract

Rat C6 cell tubulin is indistinguishable from hog brain tubulin with respect to its MW, amino acid composition and colchicine-binding activity. Microtubule assembly systems from both sources form the same structures: rings, ribbons, tubules and drug-induced polymers. There is a difference between the cultured cell and brain systems which lies in the nature of their microtubule-associated accessory proteins. C6 microtubule preparations exhibit few rings at 0.degree. C, have low polymerization yield and have a low content of accessory proteins. The addition of brain accessory proteins enhances the numbers or rings, and the yield of microtubules, to levels comparable with those of brain preparations. The polymerizing ability of C6 microtubule protein decays much faster than that of brain, but it can be restored by the addition of brain accessory protein. C6 accessory proteins apparently are more labile than their brain counterparts.