The Microtubule: A Multitasking Cellular Worker

Other microscopic employees, microtubules, will work many jobs. These strong protein filaments make up part of the cell’s skeleton and serve as tracks for shuttling internal cargo. When cells divide, it’s microtubule fibers that physically pull the chromosomes into each daughter cell. And on some cell exteriors, microtubules form long, waving hairs that sweep mucus from the lungs or guide eggs toward the uterus.

Until recently, scientists didn’t know exactly what drove microtubules to fall apart. A National Institutes of Health-funded 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 them from springing apart is the pressure from the addition of more tubulin. So when elongation ends, the microtubule deconstructs.