[The high diversity and regulation of plant water channels]

Membrane intrinsic proteins (MIPs) are a diverse class of integral membrane proteins that mediate the bi-directional flux of water (aquaporins), uncharged small solutes such as glycerol and/or gases across cellular membranes. The past year has brought significant advances in the characterization in plants of a large class this of water channel. MIPs have been identified in many single- and multi- cellular organisms. Aquaporins play important role in plant development and their adaptation to even changing environment. At the transcriptional level aquaporins have been up- or down-regulated in response to hormones, drought, salnity and light. Recent data indicate that plant aquaporin activity might be regulated by phosphorylation and intracellular protons. Novel mechanisms of regulation by hetero-tetramer formation or through control by reactive oxygen species and osmotic or hydrostatic pressure gradients is also discussed.