Aurora B controls microtubule stability to regulate abscission dynamics in stem cells

Abscission is the last step of cell division leading to the complete separation of the two sister cells and consists of the cutting of a cytoplasmic bridge. Abscission is mediated by the ESCRT membrane remodeling machinery which also triggers the severing of a thick bundle of microtubules that needs to be cleared prior to abscission. Here, we show that rather than being passive actors in abscission, microtubules control abscission speed. Using mouse embryonic stem cells, which transition from slow to fast abscission during exit from naive pluripotency, we investigate the molecular mechanism for the regulation of abscission dynamics and identify a feedback loop between the activity of Aurora B and microtubule stability. We demonstrate that naive stem cells maintain high Aurora B activity after cytokinesis. This high Aurora B activity leads to transient microtubule stabilization that delays abscission. In turn, stable microtubules promote the activity of Aurora B. When cells exit naive pluripotency, a decrease in Wnt signaling leads to a decrease in the activity of Aurora B, less stable microtubules, and a faster abscission. Overall, our data demonstrate that Aurora B-dependent microtubule stability controls abscission dynamics.