Taxol has the capacity to shift the equilibrium between the tubulin dimer and polymer in favor of the microtubule in an in vitro assembly system. The drug decreases dramatically the critical concentration of microtubule protein (MTO, tubulin plus microtubulin-associated proteins) required for microtubule assembly. Microtubules assembled in the presence of taxol are stable to polymerization by 4 mM CaCl2 and by a fivefold dilution, but they can be slowly depolymerized by podophyllotoxin or vinblastine. Taxol is unusual, compared with other small molecules such as colchicine, in its ability to bind efficiently to the assembled stead-state microtubule. Examination of the binding of taxol to cells growing in tissue culture has resulted in data that correlate well with our knowledge of the interaction of the drug with microtubules in vitro.
|Number of pages||8|
|Journal||Cold Spring Harbor Symposia on Quantitative Biology|
|State||Published - 1982|