Shear-induced ciliary autotomy mediated by a TRP channel and a voltage-dependent calcium channel

Cilium, an organelle for sensory transduction and cell motility, dynamically grows and disappears depending on stimulus perception and cell-cycle progression. Here, the mechanism for shear-induced deciliation was explored in Chlamydomonas. Deciliation occurred by shear in wild-type cells but not in cells with disrupted TRP11, a ciliary TRP channel gene, or in cells expressing TRP11 with mutated ion-conducting pore. Cells with a knockout of the CAV2 voltage-dependent calcium channel, ppr2, were also defective in shear-induced deciliation. Whereas the bending of cilia of wild-type cells converted from the asymmetric mode to the symmetric mode while shear was applied, the cilia of ppr2 cells retained the asymmetric mode. The results support the idea that the activation of the TRP11 TRP channel by shear and the generation of action potentials by the CAV2 voltage-dependent calcium channel induce an elevation of the Ca²⁺ concentration and cilia excision.