A live-cell marker to visualize the dynamics of stable microtubules

The microtubule (MT) cytoskeleton underlies processes such as intracellular transport and cell division. Immunolabeling for post-translational modifications of tubulin has revealed the presence of different MT subsets, which are believed to differ in stability and function. Whereas dynamic MTs can readily be studied using live-cell plus-end markers, the dynamics of stable MTs have remained obscure due to a lack of tools to directly visualize these MTs in living cells. Here, we present a live-cell marker to visualize stable MTs and explore their dynamics. We demonstrate that a rigor mutant of kinesin-1 binds selectively to acetylated MTs without affecting MT organization and organelle transport. These MTs are long-lived, do not depolymerize upon nocadozale-treatment or laser-based severing, and display rich dynamics, including undulation, looping and sliding. This marker will help to explore how different MT subsets contribute to cellular organization and transport.