Repurposing Cell Cycle Oscillators for Multiciliated Cell Differentiation.

Repurposing extant resources is at the basis of functional innovation in evolution. In cell biology, conserved regulatory circuits, with minor adjustments to a subset of components, can be recruited for functional novelty. A prominent example concerns multiciliated cells that generate cilia-based fluid flows, vital for organism development and homeostasis. During their post-mitotic differentiation, these cells repurpose the autonomous oscillators that normally govern the cell division cycle to drive massive production of cilia-nucleating organelles, named centrioles, in the cytoplasm without committing to cell division. In this chapter, we review recent advances in understanding how a repurposed cell cycle machinery regulates these cytoplasmic dynamics essential for motile ciliogenesis.