Effect of taxol on vinblastine sulfate-induced crystallization of tubulin

In human lung adenocarcinoma cells exposed to vinblastine (VLB) and stained with fast green, large tubulin crystals were seen in the cytoplasm. In contrast cells exposed to taxol had prominent bundles of stabilized microtubules. Pre- or co-incubation of cells with taxol before exposure to VLB prevented formation of the crystals. However, VLB did not prevent formation of stabilized microtubules by taxol if added at the same time. Under a fluorescent microscope, VLB induced crystals stained with secondary antibodies against anti-alpha- and anti-beta- tubulin antibodies. Neither of the drugs altered binding of the antibodies to these crystals.