Polyamine-Induced Disassembly of Reconstitut ed Microtubules in Vitro

Polyamines induced the rapid disassembly of microtubules reconstituted from porcine brain tubulin. Of the polyamines tested, spermine was the most effective. Alkaline α-amino acids and guanidine derivatives were less effective than polyamines. β-, γ- and υ-amino acids did not induce the disassembly of microtubules. To determine the action of polyamines, microtubule proteins were applied to a spermine-agarose affinity gel, then its eluates were identified by SDS-polyacrylamide gel electrophoresis. Tubulin and other associated proteins were eluted with 0.2 M NaCl. PC-tubulin also bound to the spermine-agarose gel. Moreover, electron microscopy showed that disk or ring structures were formed in the presence of spermine. These results indicate that spermine binds with the tubulin molecule which induces the disassembly of reconstituted microtubules in vitro. Abbreviations used: MES, morpholinoethanesulfonic acid; PIPES, piperazine-N,N’-bis(2-ethane-sulfonic acid); EGTA, ethyleneglycolbis (β-aminoethyl ether)N,N’-tetraacetic acid; PC-tubulin, phosphocellulose purified tubulin; EDC, N-ethyl-N’-(3-dimethyl aminopropyl)carbodiimide hydrochloride; MAPs, microtubule-associated proteins.