The Regulatory Mechanism for Accurate Construction of Motile Cilia in Multiciliated Cells

Motile cilia are present on the epithelial surface in large numbers to generate a directional fluid flow that is crucial for various biological processes, such as mucociliary clearance in airways, cerebrospinal fluid circulation in the brain, and fertility. Dysfunction of these cilia causes chronic tracheitis, hydrocephalus and infertility. In spite of the important role of motile cilia, little is known about the mechanism for accurate construction of intricate motile ciliary structures. Here, using a combination of proteomic analysis, super resolution microscopy, electron microscopy and live cell imaging, this article discovers that Pcm1 may undergo phase separation to form FGMs (fibrogranular materials), which regulate deuterosome size, number, and distribution, and selectively concentrate multiple important centriole-related proteins as clients. Disruption of FGMs markedly affects the ultrastructure of motile cilia. Together, these findings demonstrate that FGMs organize deuterosomes and centriole-relatd proteins to facilitate the faithful assembly of basal bodies and multiciliary axonemes.