Isolation of microtubules and microtubule-associated proteins using Paclitaxel

Paclitaxel binds to tubulin, strongly promotes microtubule assembly from subunits, and stabilizes the assembled polymer against disassembly. Because of its ability to drive the assembly reaction almost completely toward microtubules, the paclitaxel-dependent procedure outlined here is particularly useful for the isolation of microtubules from tissues in which the intracellular concentration of tubulin is low (e.g., nonneuronal sources, cultured cells, and invertebrate tissues). The microtubule-associated proteins (MAPs) remain bound to the paclitaxel-stabilized microtubules. The isolation of these MAPs by salt extraction is also described here.