Figure 7.

Models of the membrane excitation during avoiding reaction and gliding initiation

(A) In the avoiding reaction, TRP11 produces a receptor potential upon collision. The depolarization activates the voltage-dependent calcium channel CAV2 and triggers an action potential. The influx of calcium ions through CAV2 elevates the intraciliary calcium concentration and converts the bending mode from forward to reverse.

(B) Cilia oriented in opposite directions generate forces in opposing directions, resulting in no net movement (top). When Ca²⁺ influx occurs through TRP11 in one cilium (middle), the cilium stops generating force and the cell starts gliding (bottom).