It's a family act: the geminin triplets take center stage in motile ciliogenesis

The balance between proliferation and differentiation is a fundamental aspect of multicellular life. Perhaps nowhere is this delicate balance more palpable than in the multiciliated cells (MCCs) that line the respiratory tract, the ependyma, and the oviduct. These cells contain dozens to hundreds of motile cilia that beat in a concerted fashion to generate directed fluid flow over the tissue surface. Although MCCs have exited the cell cycle, remarkably, they retain the ability to duplicate their centrioles and to mature those centrioles into ciliary basal bodiestwo features, which are known to be normally under strict cell cycle control (Firat-Karalar & Stearns, 2014). How post-mitotic MCCs retain this ability, remains unclear. In the past several months, four research articles, including one from Terre etal in this issue of The EMBO Journal, have described a vital role for the geminin coiled-coil domain-containing protein (Gemc1) in the MCC gene expression program in multiple tissues and organisms, that bring us closer to understanding this question (Kyrousi etal, ; Zhou etal, ; Arbi etal, ; Terre et al, 2016).