Zinc-stimulated microtubule assembly and evidence for zinc binding to tubulin.
1. Microtubule reassembly was studied in supernatant fluids from rat brain. Tubulin in extracts from zinc-deficient animals showed an impaired ability to repolymerize compared to extracts from controls; 10 microM zinc stimulated reassembly of tubulin in extracts from zinc-deficient animals. 2. Low zinc concentrations (250-900 microM zinc in the presence of 1 mM EGTA) stimulated reassembly of tubulin in brain extracts from control rats; similar concentrations of nickel had no effect whilst cobalt was inhibitory. In the absence of EGTA 20-40 microM zinc stimulated reassembly in brain extracts from normal rats. 3. Zinc-induced changes in reassembly were associated with changes in the free sulphydryl group content of the assembled crude microtubule protein; increased assembly was associated with a higher free sulphydryl group content, decreased assembly with a lower content. 4. 65Zn was found to bind to tubulin. This binding was partly inhibited by N-ethylmaleimide.
D000818:Animals; D001665:Binding Sites / Q000187:drug effects; D001923:Brain Chemistry; D003035:Cobalt / Q000494:pharmacology; D005033:Ethylmaleimide / Q000494:pharmacology; D008297:Male; D008870:Microtubules / Q000378:metabolism*; D009532:Nickel / Q000494:pharmacology; D011485:Protein Binding; D051381:Rats; D014404:Tubulin / Q000378:metabolism*; D015032:Zinc / Q000378:metabolism / Q000494:pharmacology*
D014404:Tubulin; D003035:Cobalt; D009532:Nickel; D015032:Zinc; D005033:Ethylmaleimide