Interaction of Estramustine with Tubulin Isotypes

摘要: The interaction of the antimitotic agent estramustine with bovine microtubule proteins and purified tubulin was investigated. Direct photoaffinity labeling protein [14C]estramustine resulted in both alpha- beta-tubulin, this inhibited unlabeled a dose-dependent manner. [14C]Estramustine incorporated into soluble polymerized forms tubulin. affinity constant for binding to determined by equilibrium dialysis be 23 +/- 5 mM. Estramustine did not affect [3H]vinblastine binding, vinblastine had no effect on direct [14C]estramustine. Both rhizoxin paclitaxel decreased covalent fashion were noncompetitive inhibitors colchicine as detected fluorescence DEAE filter assays. site is therefore distinct from that may at least partially overlap paclitaxel. In brain microtubules cytoskeletal human prostatic carcinoma cells, incorporation beta III isotype found occur reduced efficiency compared other beta-tubulin isotypes alpha-tubulin. Since overexpressed resistant prostate these results indicate III-tubulin play role response effects estramustine.