Asymmetrically localized Cyclin A controls the orientation of cell division

During the development of multicellular organisms, the establishment of cell diversity and the spatial arrangement of cells within organs require fine coordination between proliferation and cell polarity. While the mechanisms governing each of these two processes are well documented, there is little information on how they are coordinated.

Agnès Audibert and her colleagues in Michel Gho's team (LBD) have shown that the Frizzled/Dishevelled complex, controlling planar polarity of epithelia, recruits Cyclin A to the apical posterior cortex of the precursors of the mechanosensory organs in the dorsal epithelium of Drosophila. This asymmetric localization of Cyclin A then regulates the orientation of the mitotic spindle of these cells by recruiting Mud/NuMA, an essential factor in the protein complex that links the mitotic spindle to the cell cortex.

This study identifies Cyclin A as a central player in the coordination between proliferation and cell polarity.

Darnat, P., Burg, A., Sallé, J., Lacoste, J., Louvet-Vallée, S., Gho, M., & Audibert, A. (2022). Cortical Cyclin A controls spindle orientation during asymmetric cell divisions in Drosophila. Nature Communications, 13(1), 2723.

Group of three dividing sensory organ precursors with accumulation of Cyclin A at the posterior apical cortex of cells (arrows).