CFTR regulation of aquaporin-mediated water transport.

The cystic fibrosis transmembrane conductance regulator (CFTR) is an anion channel responsible for the direct transport of bicarbonate and chloride. CFTR-dependent ionic transport is crucial for pH regulation and fluid homeodynamics among epithelial surfaces. Particularly, CFTR performs an essential role in the male reproductive tract, which requires a tight regulation of water and electrolytes in order to produce healthy spermatozoa. The absence or malfunction of CFTR results in cystic fibrosis, the most common lethal disease among Caucasians, that is characterized by an impaired fluid and ionic homeostasis in the whole organism. Due to the wide expression and importance of CFTR, the male reproductive tract is highly affected by cystic fibrosis, resulting in male infertility. Although CFTR is not permeable to water, this protein acts as a regulator of other protein channels, such as aquaporins. In fact, CFTR acts as a molecular partner of aquaporins in epithelial cells, regulating fluid homeodynamics. Herein, up-to-date data concerning the regulation of aquaporin-mediated water transport by CFTR will be discussed, highlighting the role of both channels in the male reproductive tract.