Modulation of microtubule dynamics during the cell cycle.

Microtubule dynamics change dramatically during the cell cycle, but the mechanisms by which these changes occur are unknown. Recent progress has been made in four areas: firstly, in the determination of changes in microtubule turnover and net tubulin polymer levels in vivo; secondly, in the elucidation of mechanisms of regulation of microtubule dynamics by microtubule-associated protein 4; thirdly, in the determination of the mechanisms by which Xenopus microtubule-associated protein regulates microtubule dynamics; and fourthly, in the elucidation of the structural basis of microtubule nucleation by gamma tubulin.