Centriolar satellites expedite mother centriole remodeling to promote ciliogenesis

Centrosomes are orbited by centriolar satellites, dynamic multiprotein assemblies nucleated by PCM1. To study the requirement for centriolar satellites, we generated mice lacking PCM1. Pcm1-/- mice display partially expressive perinatal lethality with survivors exhibiting hydrocephalus, oligospermia and cerebellar hypoplasia. Pcm1-/- multiciliated ependymal cells and PCM1-/- retinal pigmented epithelial 1 (RPE1) cells showed reduced ciliogenesis. PCM1-/- RPE1 cells displayed reduced docking of the mother centriole to the ciliary vesicle and removal of CP110 and CEP97 from the distal mother centriole, indicating compromised early ciliogenesis. We show these molecular cascades are maintained in vivo, although we propose that the cellular threshold for ciliogenesis initiation varies between cell types. We propose that PCM1 and centriolar satellites facilitate efficient trafficking of proteins to and from centrioles, including the departure of CP110 and CEP97 to initiate ciliogenesis.