Colchicine-Binding Site of Tubulin (CBS)

The colchicine-binding site is a well-characterized pocket on the tubulin protein, specifically located primarily within the β-tubulin subunit at the interface with α-tubulin in the αβ-tubulin heterodimer. This site is a major target for small-molecule inhibitors that disrupt microtubule dynamics, making it highly relevant for anticancer drug development. The binding of colchicine or other colchicine-site inhibitors (CBSIs) to this site prevents tubulin from adopting the straight conformation required for polymerization into microtubules. When colchicine binds to β-tubulin at this interface, it induces a curved conformation in the tubulin dimer. This conformational change inhibits microtubule assembly and leads to destabilization of existing microtubules. As a result, cells are arrested in mitosis due to failed spindle formation, leading ultimately to apoptosis—this underlies their use as antimitotic agents in cancer therapy.

Other names

Colchicine siteTubulin colchicine-binding domain

Inhibition of tubulin polymerization by binding to the colchicine-binding site, leading to microtubule destabilization and cell cycle arrest.