The cilium is a cell surface organelle with unique composition and shape. Although it has now been well appreciated as a signaling compartment for the vertebrate cell, the regulation and function of intraciliary calcium is less clear and sometimes controversial. This review focuses on publications regarding calcium in the cilium and the potential interactions between intraciliary calcium and signaling pathways mediated by cilia. Unresolved questions and future directions in the field are also discussed.
Keywords: calcium; cilia; left-right asymmetry; mechanosensory; polycystic kidney disease; polycystin; signaling.