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

Abstract

Plant aquaporins play an important role in water uptake and movement-an aquaporin that opens and closes a gate that regulates water movement in and out of cells. Some plant aquaporins also play an important role in response to water stress. Since their discovery, advancing knowledge of their structures and properties led to an understanding of the basic features of the water transport mechanism and increased illumination to water relations. Meanwhile, molecular and functional characterization of aquaporins has revealed the significance of their regulation in response to the adverse environments such as salinity and drought. This paper reviews the structure, species diversity, physiology function, regulation of plant aquaporins, and the relations between environmental factors and plant aquaporins. Complete understanding of aquaporin function and regulation is to integrate those mechanisms in time and space and to well regulate the permeation of water across biological membranes under changing environmental and developmental conditions.

Involvement of HbPIP2;1 and HbTIP1;1 Aquaporins in Ethylene Stimulation of Latex Yield through Regulation of Water Exchanges between Inner Liber and Latex Cells in Hevea brasiliensis

“…It was confirmed (Fig. 4) that both harbored the consensus sequences that characterize the PIP2 and g-TIP aquaporins: six conserved membrane-spanning domains, five connecting loops, NPA motifs (Chrispeels and Maurel, 1994;Maurel, 1997;Zhao et al, 2008), Ser phosphorylable residues, as well as His protonable residues, which are known to confer pH sensitivity to aquaporins (Fischer and Kaldenhoff, 2008). The HbPIP2;1 deduced protein sequence did not harbor the Cys residue adjacent to the second NPA loop that confers mercury sensitivity to most aquaporins (Preston et al, 1993;Zhang et al, 1993).…”

Analysis of transcriptional response to heat stress in Rhazya stricta

“…AQPs are classes of membrane proteins that facilitate water diffusion across cell membranes during the response/tolerance to adverse environmental stimuli [79, 80] including heat stress [81]. They are also involved in the opening and closing of cellular gates and in the physiology of water balance and water use efficiency under abiotic stresses [82]. We propose that the upregulation of the three genes encoding AQPs may contribute to thermotolerance of R. stricta leaves.…”

Exogenous ABA accentuates the differences in root hydraulic properties between mycorrhizal and non mycorrhizal maize plants through regulation of PIP aquaporins

“…Aquaporins are membrane intrinsic proteins that facilitate water and small neutral solutes flow, always following an osmotic gradient (Chrispeels and Agre 1994;Maurel 1997). The activity of aquaporins has been related to cellular and whole-plant water movement (Javot and Maurel 2002;Javot et al 2003, for recent reviews see Maurel et al 2008;Zhao et al 2008).…”