Considerable experimental evidence indicates that the primary, nonmotile cilium is a mechanosensory organelle in several epithelial cell types. As the relationship between cellular responses and nature and magnitude of applied forces is not well understood, we have investigated the effects of exposure of monolayers of renal collecting duct chief cells to orbital shaking and quantified the forces incident on cilia. An exposure of 24 h of these cells to orbital shaking resulted in a decrease of amiloride-sensitive sodium current by ∼60% and ciliary length by ∼30%. The sensitivity of the sodium current to shaking was dependent on intact cilia. The drag force on cilia due to induced fluid flow during orbital shaking was estimated at maximally 5.2 × 10−3 pN at 2 Hz, ∼4 times that of thermal noise. The major structural feature of cilia contributing to their sensitivity appears to be ciliary length. As more than half of the total drag force is exerted on the ciliary cap, one function of the slender stalk may be to expose the cap to greater drag force. Regardless, the findings indicate that the cilium is a mechanosensory organelle with a sensitivity much lower than previously recognized.
Resnick, Andrew and Hopfer, Ulrich, "Force-Response Considerations in Ciliary Mechanosensation" (2007). Physics Faculty Publications. 245.
NOTICE: this is the author’s version of a work that was accepted for publication in Biophysical Journal. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Biophysical Journal, 93, 4, August 15, 2007 DOI#10.1529/biophysj.107.105007