During cell division, the cells have to ensure that chromosomes containing genetic information are divided equally into the two daughter cells. Errors in this process can lead to cells with incorrect chromosome numbers, a hallmark of the vast majority of cancers. In order to divide, a cell must change its shape. Most cells round up at the beginning of division and then contract in the middle, leading to the separation of two new cells. These dramatic shape changes are mostly driven by the cell actin cytoskeleton, a network of rod-like polymers that supports cells shape, similarly to our skeleton supporting our body shape. However, very little is known about the organization and the regulation of the cytoskeleton during cell division. The aim of my research is to understand how the cell reorganizes its cytoskeleton to achieve the shape changes required during cell division.