Electrical Signaling in Motile and Primary Cilia

Cilia are highly conserved for their structure and also for their sensory functions. They serve as antennae for extracellular information. Whether the cilia are motile or not, they respond to environmental mechanical and chemical stimuli and send signals to the cell body. The information from extracellular stimuli is commonly converted to electrical signals through the repertoire of ion-conducting channels in the ciliary membrane, which results in changes in concentrations of ions; especially calcium ions, in the cilia. These changes, in turn, affect motility and the ability of the signaling pathways in the cilia and cell body to carry on the signal transduction. We review here the activities of ion channels in cilia in animals from protists to vertebrates.