Plakophilin 3 Is Involved in Basal Body Docking in Multiciliated Cells

TL;DR

This study shows that plakophilin 3 helps anchor cilia in multiciliated cells, and its absence causes defects in fluid flow and cilia positioning.

Contribution

The novel finding is that plakophilin 3, a desmosomal protein, is essential for basal body docking and ciliary function in multiciliated cells.

Findings

Plakophilin 3 localizes to the striated rootlet in Xenopus laevis multiciliated cells.

Knockdown of plakophilin 3 causes defects in cilia-generated fluid flow and basal body docking.

The defects are cell-autonomous and not due to changes in the actin cytoskeleton or cell intercalation.

Abstract

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 Xenopus laevis 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.

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