Plakophilin 3 Is Involved in Basal Body Docking in Multiciliated Cells.

Multiciliated cells generate fluid flow along epithelial surfaces, and defects in their development or function cause primary ciliary dyskinesia. The fluid flow is generated by the coordinated beating of motile cilia, which are microtubule-based organelles. The base of each cilium, the basal body, is anchored to the apical cell membrane and surrounded by a dense apical cytoskeleton of actin, microtubules, and intermediate filaments. Several cell adhesion proteins play a role in the connection of the basal body to the apical cytoskeleton. Here, we show that the desmosomal protein plakophilin3, a member of the armadillo family of proteins, localizes to the striated rootlet in multiciliated cells. Knockdown of plakophilin 3 leads to significant defects in cilia-generated fluid flow and basal body docking. These defects are cell-autonomous and independent of cell intercalation and gross changes in the actin cytoskeleton. These findings suggest a crucial role for PKP3 in basal body apical migration and docking in multiciliated cells, highlighting a novel connection between desmosomal proteins and ciliary function.