Aquaporin (水通道蛋白)

Aquaporins (AQPs) are integral membrane proteins that facilitate the transport of water across biological membranes along an osmotic gradient. There have been 13 AQP isoforms (AQP0-AQP12) identified in humans and rodents to date. AQP0-2, 4-6 and 8 are generally considered to be exclusively water channels, whereas AQP3, 7, 9 and 10 are referred to as aquaglyceroporins, as they are also permeated by glycerol. AQPs usually adopt a tetramer conformation within the cell membrane, with each monomer consisting of a single aqueous pore that is permeable to water. The movement of water and solutes through AQP channels is a passive process that is dependent on the concentration of the transported molecule.