Molecular physiology of aquaporins in plants

Aquaporin structure–function relationships: Water flow through plant living cells

“…Once a protein is involved, the cell has the ability to regulate its abundance (transcriptional or post-transcriptional) or to modulate its activity [2,32]. Water permeability of the plasma membrane and tonoplast through the aquaporins depends on their quantity, activity, and substrate specificity [33].…”

“…In part because of this very high diversity, the knowledge about plant aquaporin expression and subcellular localization is far from complete [34]. Thus, future investigations on the aquaporin family of proteins will provide important information not only on the physiology of membrane transport processes in many cell types, but also on the targeting and trafficking signals that allow proteins to enter distinct intracellular vesicular pathways in cells [6,32,34].…”

“…Therefore, the expression of aquaporin genes may be independently regulated in an organ and stage-specific manner, while the amount of aquaporin protein can be regulated at the translational level and by the rate of protein turnover [13,33,43,44]. Meanwhile there are numerous reports providing clear evidence that the abundance of aquaporins can be regulated by developmental and environmental factors [6,13,32]. Monitoring aquaporin gene expression patterns in many plant species in specific tissues, cell types or in response to phytohormones or environmental factors has highlighted the putative roles of water channels [13,32,44,45].…”

“…Meanwhile there are numerous reports providing clear evidence that the abundance of aquaporins can be regulated by developmental and environmental factors [6,13,32]. Monitoring aquaporin gene expression patterns in many plant species in specific tissues, cell types or in response to phytohormones or environmental factors has highlighted the putative roles of water channels [13,32,44,45]. Currently, modulation of aquaporin expression in plant is considered the strategy of choice for elucidating the role of aquaporins in plant physiology [13].…”

“…Regardless of whether all or only the majority of the plant MIPs are aquaporins, it is clear that a large number of aquaporins are present in plants, some localized in the tonoplast, some in the plasma membrane and some possibly localized in endomembranes [4,6,11,18,20,21,26,32,45]. MIP-B was found in fractions containing tonoplast proteins and possibly in a fraction of intermediate density, distinct from both plasma membrane and tonoplast, and also distinct from the fractions in which MIP-A was located [19,34,50].…”