Microtubules get dynamic

Microtubules were seen first as static struts in EM images (see “Microtubules get a name” JCB 168:852) and then as polymers created from a defined protein component (see “The discovery of tubulin” JCB 169:552). It took a series of studies in the 1980s to emphasize that dynamics were essential for microtubule action in the cell.

First, in vitro polymerization was needed as proof that there was no additional magic ingredient needed for microtubule formation. That achievement was forthcoming once EGTA was added to the mix to get rid of inhibitory calcium (Weisenberg, 1972). But this didn't exactly bring hordes rushing into the field of in vitro microtubule polymerization. Summers and Kirschner (1979) did find that microtubule growth was polar, occurring more readily at one end of the polymer than another. But it would...