Submitted by Dr R. Inchingolo on Tue, 04/02/2020 - 13:18
The researchers used proteomics to identify key factors controlling actin organisation in mitosis
During cell division, cells have to ensure that chromosomes are partitioned equally between the two daughter cells. Errors in this process can lead to daughter cells with incorrect chromosome numbers, a hallmark of the vast majority of cancers. At the onset of division, most cells round up, a process referred to as mitotic rounding. Mitotic rounding is thought to be crucial for accurate division, by generating sufficient space to facilitate chromosome organisation in metaphase and subsequent partitioning between daughter cells.
Mitotic rounding is primarily driven by a reorganisation of the cellular actin cytoskeleton into a thin contractile actin cortex under the plasma membrane, supporting the round cell shape. Accurate control of cortex organisation and contractile cortical tension is essential for successful division. In this paper, Serres et al. used proteomics to identify key factors controlling actin organisation in mitosis. Surprisingly, they identified vimentin, an intermediate filament protein, as a key regulator of the mitotic cortex. Intermediate filaments were not generally thought to play an important role in mitosis. Serres et al demonstrated that a vimentin network formed right underneath the mitotic cortex supports cell rounding, and is required for accurate chromosome partitioning when cells divide in physical confinement.
Together, this work highlights that the actin cortex, which is often studied in isolation, is tightly integrated with other cellular components. It also sheds light on general principles controlling cell shape changes in cell division.
Reference: Serres MP, Samwer M, Truong Quang BA, Lavoie G, Perera U, Görlich D, Charras G, Petronczki M, Roux PP, Paluch EK. (2020). F-actin interactome reveals vimentin as a key regulator of actin organization and cell mechanics in mitosis. Dev Cell, 52:1-13.