Ezrin knockdown reduces procaterol-stimulated ciliary beating without morphological changes in mouse airway cilia

Mucociliary clearance, which is conducted by beating cilia cooperating with the surface mucous layer, is a major host defense mechanism of the airway epithelium. Ezrin, a crosslinker between membrane proteins and the actin cytoskeleton, is located in microvilli and around the basal bodies in airway ciliary cells. It is also likely that ezrin plays an important role in apical localization of beta(2) adrenergic receptor (beta(2)AR) in airway ciliary cells. Here, we studied the physiological roles of ezrin by using trachea and airway epithelial cells prepared from ezrin-knockdown (Vil2(kdlkd)) mice. The trachea and airway ciliary cells of Vil2(kdlkd )mice presented a normal morphology and basal body orientation, suggesting that ezrin is not directly involved in development and planar cell polarity of cilia. Procaterol stimulates ciliary beating (frequency and amplitude) via beta(2)AR in the airway ciliary cells. In the Vil2(kdlkd) mice, airway ciliary beating stimulated with procaterol was partly inhibited due to the impairment of cell surface expression of beta(2)AR. These results suggest that ezrin regulates the beating of airway ciliary cells by promoting the apical surface localization of beta(2)AR. This article has an associated First Person interview with the first author of the paper.