Published in BBA - Biomembranes
The complete 3′ UTR sequence encoded by the human aquaporin-1 gene is reported. The sequence encompassed by two cDNA clones showed, 33 nucleotides of 5′ UTR sequence, a coding sequence of 807 nucleotides and 1886 nucleotides corresponding to the complete 3′ UTR sequence. High similarity with 3′ UTR sequences from rat and mouse counterparts was foun...
Published in Protoplasma
The plasmalemma ofArabidopsis thaliana contains several different aquaporins. These members of the major-intrinsic-protein family are permeable and selective for water. The apparent redundancy of aquaporins might be explained by tissue-specific expression of the corresponding gene. In order to investigate and compare the expression levels of five g...
Published in Pflügers Archiv
The anti-diuretic hormone vasopressin (AVP) regulates water excretion from the kidney by increasing the water permeability of the collecting duct. AVP binds to V2-receptors and induces the translocation of aquaporin-2 water channels (AQP-2) into the apical plasma membrane of principal cells. By this mechanism AVP controls water reabsorption in the ...
Published in Nephron Experimental Nephrology
Specific urea transporters are responsible for the rapid urea movements occurring in precise medullary structures of the mammalian kidney. Three of them, ensuring facilitated passive transports, have been cloned yet: UT2-long is responsible for the high vasopressin-dependent urea permeability of the terminal inner medullary collecting ducts; UT2-sh...
Published in Cell and Tissue Research
Aquaporin-5 (AQP5) is a water channel protein and is considered to play an important role in water movement across the plasma membrane. We raised anti-AQP5 antibody and examined the localization of AQP5 protein in rat salivary and lacrimal glands by immunofluorescence microscopy. AQP5 was found in secretory acinar cells of submandibular, parotid, a...
Published in Comparative Haematology International
The diffusional water permeability (Pd) of camel and alpaca red blood cells (RBCs) was measured by a doping nuclear magnetic resonance (NMR) technique on control cells and following inhibition withp-chloromercuribenzene sulphonate (PCMBS). The values ofPd were, in the case of alpaca RBC≈4.6×10−3 cm/s at 25°C, 5.4×10−3 cm/s at 30°C, 6.6×10−3 cm/s at...
Published in Protoplasma
Water uptake ofArabidopsis thaliana protoplasts was measured after transfer into hypo-osmotic conditions. The time-dependent swelling of protoplast populations was monitored by a Coulter counter device. In order to ascertain the contribution of the plasma membrane intrinsic protein 1b (PIP1b) to the membrane's water permeability, protoplasts of fiv...
Published in BBA - Biomembranes
Aquaporins are water channel proteins belonging to the major intrinsic protein (MIP) superfamily of membrane proteins. More than 150 MIPs have been identified in organisms ranging from bacteria to animals and plants. In plants, aquaporins are present in the plasma membrane and in the vacuolar membrane where they are abundant constituents. Functiona...
Published in Planta
It is usually assumed that aquaporins present in the cellular membranes could be an important route in the control of water flux in plants, but evidence for this hypothesis is scarce. In this paper, we report measurements of the osmotic permeability (Pos) of protoplasts isolated from hypocotyls of wild-type and mutant Arabidopsis thaliana (L.) Heyn...
Published in Planta
Tomato (Lycopersicon esculentum Mill.) ripening-associated membrane protein (TRAMP) is a channel protein of the membrane intrinsic protein (MIP) class encoded by the cDNA clone pNY507 [R.G. Fray et al. (1994) Plant Mol Biol 24: 539–543]. It has been suggested that these proteins encode water channels or aquaporins. TRAMP mRNA accumulated in all tom...
