Ciliary subcompartments and cysto-proteins.

Renal cystic diseases are conditions in which parts of or entire nephrons become enlarged and create fluid-filled cysts. These cysts occur in many genetic diseases. Most of the products of causative genes, termed cysto-proteins, are localized in cilia and/or centrioles. In addition, mutant mice lacking cilia develop renal cysts. Therefore, cilia are thought to have an important role in renal cystogenesis. The cilium is a tiny projection from the cell surface; however, it can be divided into several subcompartments. These subcompartments have specific roles. This review attempts to classify cysto-proteins based on their localization in ciliary subcompartments with the aim of defining relationships among them and of identifying their exact intraciliary functions.