LAUSR

Proteins that control cell cycle progression also drive multiciliated cell differentiation Multiciliated cells (MCCs) are a specialized population of postmitotic cells that are decorated with tens to hundreds of hairlike protrusions, termed motile cilia, that beat back and forth to direct fluid flow across an epithelium (1). MCCs line the respiratory tract, brain ventricles, and reproductive tracts of vertebrates and play a crucial role in tissue homeostasis; defects in the formation or movement of motile cilia can cause fertility defects, chronic respiratory infections, and/or a buildup of fluid in the brain. Despite their importance to human health, the pathways controlling the production of motile cilia in differentiating MCCs remain poorly understood. On page 803 of this issue, Al Jord et al. (2) shed light on this question by showing that multiciliated progenitor cells implement components of the mitotic cell cycle machinery to coordinate events that are required for motile ciliation and cellular differentiation, while avoiding cell division (mitosis).