The cellular dynamics of plant aquaporin expression and functions.

Aquaporins are channel proteins that facilitate the transport of water and small neutral molecules, including gases, across cell membranes of most of the living organisms. Integrative studies have stressed the role of aquaporins in maintaining the whole plant water and nutrient status. Cellular aspects of plant aquaporin functions and regulations are also extensively investigated. The present review provides a glance at recent progresses in this area. One first direction concerns the mechanisms that determine aquaporin targeting to specific subcellular membranes and a dynamic and stimulus-dependent control of their density in these membranes. The regulation of aquaporin opening and closing and its links to cell signalling cascades are also discussed. Multiple cellular functions are now attributed to plant aquaporins. They include the dynamic equilibration and subcellular partitioning of their various substrates and a contribution to cell expansion and possibly cell division.