The spindle orientation machinery beyond mitosis: When cell specialization demands polarization

Abstract

Mitosis is a process requiring strict spatial organization of cellular components. In particular, the orientation of the mitotic spindle with respect to the tissue defines the division plane. In turn, the orientation of cell division can regulate tissue morphology or the fate of daughter cells. While we have learned much about the mechanisms of mitotic spindle orientation, recent studies suggest that the proteins implicated can also play important roles in post-mitotic cells. Interestingly, post-mitotic protein function often involves polarizing the cell cytoskeleton during differentiation, mirroring its ability to orient the mitotic spindle during division. This review focuses on alternative functions of the spindle orientation machinery after division, when the cell undergoes a specialization process associated with differentiation or mature function, and discusses diseases associated to those alternative functions.