In this animation, tubulin proteins snap into place like Lego blocks to build a microtubule, part of the cell’s skeleton. When construction ends, this long hollow cylinder falls to pieces from its top end. The breakdown is critical for many basic biological processes, including cell division, when rapidly shortening microtubules pull chromosomes into each daughter cell.
Until recently, scientists didn’t know exactly what drove microtubules to fall apart. A research team led by Eva Nogales of the Lawrence Berkeley National Laboratory and the University of California, Berkeley, now has an explanation.
Using high-powered microscopy, the scientists peered into the structure of a microtubule and found how a chemical reaction puts the stacking tubulin proteins under intense strain. The only thing keeping the proteins from springing apart is the pressure from the addition of more tubulin. So when assembly stops, the microtubule deconstructs.
The team also learned that Taxol, a common cancer drug, relieves this tension and allows microtubules to remain intact indefinitely. With microtubules frozen in place, a cancer cell cannot divide and eventually dies.
Because of this research, scientists now better understand both the success behind a common cancer drug and the molecular basis underlying the workings of microtubules.
Learn more:
University of California, Berkeley News Release 
Nogales Lab