The importance of aquaporin water channel protein structures

The history of the water channel and recent structural and functional analy ses of aquaporins are reviewed, These ubiquitous channels are important for bacteria, plants and animals, exhibit a pronounced sequence homology and s hare functional as well as structural similarities. Aquaporins allow water or small specific solutes to pass unhindered, but black the passage of ions to prevent dissipation of the transmembrane potential. Besides advances in structure determination, recent experiments suggest that many of these cha nnels are regulated by pH variations, phosphorylation and binding of auxili ary proteins.