The keyword ("aquaporin," "major intrinsic protein" "tonoplast
intrinsic protein" "plasma membrane intrinsic protein" "small basic intrinsic protein" "nodulin-26-like intrinsic protein," "PIP," "TIP," "NIP," "SIP") searches in the EST annotation identified 1,347 ESTs, while the "water transport" GO expression identified 342 ESTs (Figure 1).
Modulation by Cytosolic Components of Proton Pump Activities in Plasma Membrane and Tonoplast
from Cucumis sativus Roots During Salt Stress.
> 700 kD in higher plants, a highly abundant protein making up to 6.5-35% of the total tonoplast
protein in different species [4,26,43].
Chrispeels, "The plasma membrane of Arabidopsis thaliana contains a mercury-insensitive aquaporin that is a homolog of the tonoplast
water channel protein TIP," Plant Physiology, vol.
Proteomic analysis of plasma membrane and tonoplast
from the leaves of mangrove plant Avicennia officinalis.
Abbreviations: AQP, aquaporin; ar/R, aromatic-arginine selectivity filter; Arg, arginine; ATP, adenosine triphosphate; BIB, big brain; Eglp, entomoglyceroporin; Ga, billions of years ago; GIP, GlpF-like intrinsic protein; Glp, aquaglyceroporin; HGT, horizontal gene transfer; HIP, hybrid intrinsic protein; His, histidine; Leu, leucine; LHIP, Lygus hesperus integral protein-like channel; NIP, plant nodulin 26-like integral protein; NPA, asparagine-proline-alanine; NPC, asparagine-proline-cysteine; PIP, plasma membrane intrinsic protein; RPIP, Rhodnius prolixus integral protein-like channel; SIP, small basic intrinsic protein; TIP, plant tonoplast
intrinsic protein; TMD, transmembrane domain; Trp, tryptophan; XIP, X intrinsic protein; WGD, whole genome duplication.
It is possible that transport of complexed As (III) or even free As (III) across the tonoplast
membrane is a potentially the rate-limiting step in overall arsenic tolerance and accumulation.
The cotton GhNHX1 gene encoding a novel putative tonoplast
[Na.sup.+]/H+ antiporter plays an important role in salt stress.
(1996), the cell pro-embryos may be covered by vacuolated cytoplasm that can exist only in a small space between the plasma membrane and the tonoplast
. Stein et al.
Characterization and expression of plasma and tonoplast
membrane aquaporins in primed seed of Brassica napus during germination under stress conditions, Plant Mol.
These authors suggest that a possible dysfunction in the cellular membranes alters the osmotic gradient of the tonoplast
vacuole: Aqueous cavity within the cytoplasm and surrounded by the tonoplast
that stores low molecular weight ions and molecules.