Abstract
The long-standing biophysical question of how water crosses plasma membranes has been answered by the recent discovery of the aquaporins. Identification of this large family of membrane water-transport proteins has generated new questions about the physiological functions, tissue distributions, and regulatory mechanisms of individual aquaporins. The fast pace of developments in this field has also resulted in major discrepancies in published reports which warrant resolution.
Abbreviations: AQP—aquaporin, cRNA—complementary RNA, MIP—major intrinsinc protein of lens, PCR—polymerase chain reaction
References
- 1.Agre P, Preston GM, Smith BL, Jung JS, Raina S, Moon C, Guggino WB, Nielsen S. Aquaporin CHIP: the archetypal molecular water channel. Am J Physiol. 1993;34:F463–F476. doi: 10.1152/ajprenal.1993.265.4.F463. [DOI] [PubMed] [Google Scholar]
- 2.Knepper M. The aquaporin family of molecular water channels. Proc Natl Acad Sci USA. 1994;91:6255–6258. doi: 10.1073/pnas.91.14.6255. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 3.Agre P, Sasaki S, Chrispeels MJ. Aquaporins: a family of water channel proteins [letter] Am J Physiol. 1993;34:F461. doi: 10.1152/ajprenal.1993.265.3.F461. [DOI] [PubMed] [Google Scholar]
- 4.Gorin MB, Yancey SB, Cline J, Revel JP, Horwitz J. The major intrinsic protein (MIP) of lens fiber membrane. Cell. 1984;39:49–59. doi: 10.1016/0092-8674(84)90190-9. [DOI] [PubMed] [Google Scholar]
- 5.Maurel C, Reizer J, Schroeder JI, Chrispeels MJ. The vacuolar membrane protein γ-TIP creates water specific channels in Xenopus oocytes. EMBO J. 1993;12:2241–2247. doi: 10.1002/j.1460-2075.1993.tb05877.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 6.Preston GM, Agre P. Isolation of the cDNA for erythrocyte integral membrane protein of 28 kilodaltons: member of an ancient channel family. Proc Natl Acad Sci USA. 1991;88:11110–11114. doi: 10.1073/pnas.88.24.11110. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 7.Lanahan A, Williams JB, Sanders LK, Nathans D. Growth factor-induced delayed early response genes. Mol Cell Biol. 1992;12:3919–3929. doi: 10.1128/mcb.12.9.3919. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 8.Preston GM, Carroll TP, Guggino WB, Agre P. Appearance of water channels in Xenopus oocytes expressing red cell CHIP28 protein. Science. 1992;256:385–387. doi: 10.1126/science.256.5055.385. [DOI] [PubMed] [Google Scholar]
- 9.Zhang R, Skach W, Hasegawa H, Van Hoek AN, Verkman AS. Cloning, functional analysis and cell localization of a kidney proximal tubule water transporter homologous to CHIP28. J Cell Biol. 1993;120:359–369. doi: 10.1083/jcb.120.2.359. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 10.Patil RV, Yang X, Saito I, Coca-Prados M, Wax MB. Cloning of a novel cDNA homologous to CHIP28 water channel from ocular ciliary epithelium. Biochem Biophys Res Commun. 1994;204:861–866. doi: 10.1006/bbrc.1994.2539. [DOI] [PubMed] [Google Scholar]
- 11.Deen PMT, Dempster JA, Wieringa B, Van Os CH. Isolation of a cDNA for rat CHIP28 water channel: high expression in kidney cortex and inner medulla. Biochem Biophys Res Commun. 1992;188:1267–1273. doi: 10.1016/0006-291x(92)91368-z. [DOI] [PubMed] [Google Scholar]
- 12.Fushimi K, Uchida S, Hara Y, Hirata Y, Marumo F, Sasaki S. Cloning and expression of apical membrane water channel of rat kidney collecting tubule. Nature. 1993;361:549–552. doi: 10.1038/361549a0. [DOI] [PubMed] [Google Scholar]
- 13.Ishibashi K, Sasaki S, Fushimi K, Uchida S, Kuwahara M, Saito H, Furukawa T, Nakajima K, Yamaguchi Y, Gojobori T, Marumo F. Molecular cloning and expression of a member of the aquaporin family with permeability to glycerol and urea in addition to water expressed at the basolateral membrane of kidney collecting duct cells. Proc Natl Acad Sci USA. 1994;91:6269–6273. doi: 10.1073/pnas.91.14.6269. of special interest. [DOI] [PMC free article] [PubMed] [Google Scholar]; The cDNA encoding the third aquaporin is identified. AQP3 resides in basolateral membranes of kidney collecting duct and intestine, and is also somewhat permeable to glycerol and urea.
- 14.Echevarria M, Windhager EE, Tate SS, Frindt G. Cloning and expression of AQP3, a water channel from the medullary collecting duct of rat kidney. Proc Natl Acad Sci USA. 1994;91:10997–11001. doi: 10.1073/pnas.91.23.10997. of special interest. [DOI] [PMC free article] [PubMed] [Google Scholar]; These investigators independently isolated the cDNA for AQP3 in a study supporting the conclusions of [13].
- 15.Ma T, Frigeri A, Hasegawa H, Verkman AS. Cloning of a water channel homolog expressed in brain meningeal cells and kidney collecting duct that functions as a stilbene sensitive glycerol transporter. J Biol Chem. 1994;269:21845–21849. of special interest. [PubMed] [Google Scholar]; These investigators independently isolated the cDNA for AQP3 which they termed ‘GLIP.’ The GLIP sequence appearing in GenBank (accession number L28114) is listed as a rat cDNA but corresponds to the human cDNA. This study contrasts markedly with [13,14], as these investigators detected permeability to glycerol but not water, and their cDNA probe reacted with mRNA of an entirely different size and tissue distribution. These discrepancies await resolution.
- 16.Verbavatz JM, Van Hoek AN, Ma T, Sabolic I, Valenti G, Ellisman MH, Ausiello DA, Verkman AS, Brown D. A 28 kDa sarcolemmal antigen in kidney principal cell basolateral membranes: relationship to orthogonal arrays and MIP26. J Cell Sci. 1994;107:1083–1094. doi: 10.1242/jcs.107.4.1083. [DOI] [PubMed] [Google Scholar]
- 17.Jung JS, Bhat RV, Preston GM, Guggino WB, Baraban JM, Agre P. Molecular characterization of an Aquaporin cDNA from brain: candidate osmoreceptor and regulator of water balance. Proc Natl Acad Sci USA. 1994;91:13052–13056. doi: 10.1073/pnas.91.26.13052. of special interest. [DOI] [PMC free article] [PubMed] [Google Scholar]; The cDNA encoding AQP4 was shown to be expressed primarily in brain by RNase protection assays. The transcript was identified by in situ hybridization in vasopressin-secretory neurons of hypothalamus and Purkinje cells of cerebellum.
- 18.Hasegawa H, Ma T, Skach W, Matthay MA, Verkman AS. Molecular cloning of a mercurial-insensitive water channel expressed in selected water-transporting tissues. J Biol Chem. 1994;269:5497–5500. of special interest. [PubMed] [Google Scholar]; These investigators independently cloned an aquaporin virtually identical to AQP4 but termed ‘MIWC’ as it is insensitive to mercury. Expression was noted in several tissues including kidney and lung but was not quantitated.
- 19.Engel A, Walz T, Agre P. The aquaporin family of membrane water channels. Curr Opin Struct Biol. 1994;4:545–553. [Google Scholar]
- 20.Aerts T, Xia AJ, Slegers H, De Block J, Clauwaert J. Hydrodynamic characterization of the major intrinsic protein from the bovine lens fiber membranes. J Biol Chem. 1990;265:8675–8680. [PubMed] [Google Scholar]
- 21.Smith BL, Agre P. Erythrocyte Mr 28,000 transmembrane protein exists as a multi-subunit oligomer similar to channel proteins. J Biol Chem. 1991;266:6407–6415. [PubMed] [Google Scholar]
- 22.Verbavatz JM, Brown D, Sabolic I, Valenti G, Ausiello DA, Van Hoek AN, Ma T, Verkman AS. Tetrameric assembly of CHIP28 water channels in liposomes and cell membranes: a freeze fracture study. J Cell Biol. 1993;123:605–618. doi: 10.1083/jcb.123.3.605. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 23.Walz T, Smith BL, Agre P, Engel A. The three-dimensional structure of human erythrocyte aquaporin CHIP. EMBO J. 1994;13:2985–2993. doi: 10.1002/j.1460-2075.1994.tb06597.x. of special interest. [DOI] [PMC free article] [PubMed] [Google Scholar]; Tilt analysis of two-dimensional membrane crystals revealed an asymmetric projection of AQP1 in membranes. A widely spaced tetrameric assembly lies close to the extracellular face of the membrane bilayer and a narrowly spaced tetramer projects farther from the cytoplasmic face.
- 24.Walz T, Smith BL, Zeidel ML, Engel A, Agre P. Biologically active two-dimensional crystals of aquaporin CHIP. J Biol Chem. 1994;269:1583–1586. [PubMed] [Google Scholar]
- 25.Mitra AK, Yeager M, Van Hoek AN, Wiener MC, Verkman AS. Projection structure of the CHIP28 water channel in lipid bilayer membranes at 12 Å resolution. Biochemistry. 1994;33:12735–12740. doi: 10.1021/bi00209a001. [DOI] [PubMed] [Google Scholar]
- 26.Reizer J, Reizer A, Saier MH. The MIP family of integral membrane channel proteins: sequence comparisons, evolutionary relationships, reconstructed pathway of evolution and proposed functional differentiation of the two repeated halves of the proteins. Crit Rev Biochem Mol Biol. 1993;28:235–257. doi: 10.3109/10409239309086796. [DOI] [PubMed] [Google Scholar]
- 27.Horwitz J, Bok D. Conformational properties of the main intrinsic polypeptide (MIP) isolated from lens plasma membranes. Biochemistry. 1987;26:8092–8098. doi: 10.1021/bi00399a012. [DOI] [PubMed] [Google Scholar]
- 28.Van Hoek AN, Wiener M, Bickenese S, Mircke L, Biwersi J, Verkman AS. Secondary structure analysis of purified functional CHIP28 water channels by CD and FTIR spectroscopy. Biochemistry. 1993;32:11847–11856. doi: 10.1021/bi00095a013. [DOI] [PubMed] [Google Scholar]
- 29.Nielsen S, Smith BL, Christensen EI, Knepper MA, Agre P. CHIP28 water channels are localized in constitutively water-permeable segments of the nephron. J Cell Biol. 1993;120:371–383. doi: 10.1083/jcb.120.2.371. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 30.Zeidel ML, Nielsen S, Smith BL, Ambudkar SV, Maunsbach AB, Agre P. Ultra-structure, pharmacologic inhibition, and transport selectivity of aquaporin channel-forming integral protein in proteoliposomes. Biochemistry. 1994;33:1606–1615. doi: 10.1021/bi00172a042. of special interest. [DOI] [PubMed] [Google Scholar]; The biophysical behavior of proteoliposomes containing highly purified AQP1 protein is defined.
- 31.Smith BL, Preston GM, Spring FA, Anstee DJ, Agre P. Human red cell aquaporin CHIP: I. Molecular characterization of ABH and Colton blood group antigens. J Clin Invest. 1994;94:1043–1049. doi: 10.1172/JCI117418. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 32.Preston GM, Smith BL, Zeidel ML, Moulds JJ, Agre P. Mutations in aquaporin-1 in phenotypically normal humans without functional CHIP water channels. Science. 1994;265:1585–1587. doi: 10.1126/science.7521540. of outstanding interest. [DOI] [PubMed] [Google Scholar]; Although gene disruption of the AQP1 gene was expected to be lethal, human ‘knockout’ mutants suffered no significant clinical effect, suggesting that either the protein plays no important role in many tissues, or that the body may have redundant mechanisms to overcome its deficit.
- 33.Raina S, Preston GM, Guggino WB, Agre P. Molecular cloning and characterization of an aquaporin cDNA from salivary, lacrimal, and respiratory tissues. J Biol Chem. 1995;270:1908–1912. doi: 10.1074/jbc.270.4.1908. of special interest. [DOI] [PubMed] [Google Scholar]; Characterization of the cDNA encoding the fifth mammalian aquaporin suggests a role in secretion of saliva, tears, and sputum.
- 34.Sasaki S, Fushimi K, Saito H, Saito F, Uchida S, Ishibashi I, Kuwahara M, Ikeuchi T, Inui K, Nakajima K. Cloning, characterization and chromosomal mapping of human Aquaporin of collecting duct. J Clin Invest. 1994;93:1252–1259. doi: 10.1172/JCI117079. [published erratum appears in J Clin Invest 1994, 94:2169.] [DOI] [PMC free article] [PubMed] [Google Scholar]
- 35.Deen PM, Verdijk MA, Knoers NV, Wieringa B, Monnens LA, Van Os CH, Van Oost BA. Requirement of human renal water channel aquaporin-2 for vasopressin-dependent concentration of urine. Science. 1994;264:92–95. doi: 10.1126/science.8140421. of outstanding interest. [DOI] [PubMed] [Google Scholar]; Naturally occuring ‘knockout’ mutations in AQP2 are described in a patient with severe nephrogenic diabetes insipidus.
- 36.Fischbarg J, Li J, Cheung M, Czegledy F, Iserovich P, Kuang K. Predictive evidence for a porin-type β-barrel fold in CHIP28 and other members of the MIP family. A restricted-pore model common to water channels and facilitators. J Membr Biol. 1995;143:177–188. doi: 10.1007/BF00233446. of outstanding interest. of special interest. [DOI] [PMC free article] [PubMed] [Google Scholar]; A novel structure of aquaporin subunits is proposed on theoretical grounds, but the predictions are not compatible with structures proposed in [39,43].
- 37.Skach W, Calayag MC, Lingappa V. Evidence for an alternate model of human P-glycoprotein structure and biogenesis. J Biol Chem. 1993;268:6903–6908. [PubMed] [Google Scholar]
- 38.Loo TW, Clarke DM. Membrane topology of a cysteine-less mutant of human P-glycoprotein. J Biol Chem. 1995;270:843–848. doi: 10.1074/jbc.270.2.843. [DOI] [PubMed] [Google Scholar]
- 39.Skach WR, Shi L, Calayag MC, Frigeri A, Lingappa VR, Verkman AS. Biogenesis and transmembrane topology of the CHIP28 water channel at the endoplasmic reticulum. J Cell Biol. 1994;125:803–815. doi: 10.1083/jcb.125.4.803. of special interest. of outstanding interest. [DOI] [PMC free article] [PubMed] [Google Scholar]; A controversial four bilayer spanning model is proposed, but the predictions are not compatible with structures proposed in [36,43].
- 40.Preston GM, Jung JS, Guggino WB, Agre P. Membrane topology of aquaporin CHIP: analysis of functional epitope scanning mutants by vectorial proteolysis. J Biol Chem. 1994;269:1668–1673. of special interest. [PubMed] [Google Scholar]; The six bilayer spanning model originally proposed for MIP [4] is confirmed in AQP1.
- 41.Preston GM, Jung JS, Guggino WB, Agre P. The mercury sensitive residue at cysteine 189 in the CHIP28 water channel. J Biol Chem. 1993;268:17–20. [PubMed] [Google Scholar]
- 42.Zhang R, Van Hoek AN, Biwersi J, Verkman AS. Mutation at cysteine 189 blocks the water permeability of rat kidney water channel CHIP28k. Biochemistry. 1993;32:2938–2941. doi: 10.1021/bi00063a002. [DOI] [PubMed] [Google Scholar]
- 43.Jung JS, Preston GM, Smith BL, Guggino WB, Agre P. Molecular structure of the water channel through Aquaporin CHIP: the hourglass model. J Biol Chem. 1994;269:14648–14654. of outstanding interest. [PubMed] [Google Scholar]; This study demonstrated the functional independence of the CHIP/AQP1 subunits by expression of mixed tandem dimers composed of mercury-sensitive and mercury-insensitive subunits. A second mercury-sensitive site is introduced in the first half of the molecule. The functional need for oligomerization was established by complementation of functionally inactive subunits. The hourglass model containing a uniquely obverse symmetry was developed to integrate information from multiple studies.
- 44.Shi L, Skach WR, Verkman AS. Functional independence of monomeric CHIP28 water channels revealed by expression of wild-type mutant heterodimers. J Biol Chem. 1994;269:10417–10422. of outstanding interest. of special interest. [PubMed] [Google Scholar]; Functional independence of AQP1 subunits was established by expression of dimeric polypeptides as in [43].
- 45.Mulders SM, Preston GM, Deen PMT, Guggino WB, Van Os CH, Agre P. Water channel properties of major intrinsic protein of lens. J Biol Chem. 1995;270:9010–9016. doi: 10.1074/jbc.270.15.9010. of special interest. [DOI] [PubMed] [Google Scholar]; Although commonly thought to be a ‘non-specific ion channel,’ MIP was shown in the oocyte expression system to confer no increase in ion conductance but enhanced water permeability ∼10% of the level induced by AQP1.
- 46.Ehring GR, Zampighi GA, Horwitz J, Bok D, Hall JE. Properties of channels reconstituted from the major intrinsic protein of lens fiber membranes. J Gen Physiol. 1990;96:631–664. doi: 10.1085/jgp.96.3.631. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 47.Kushmerick C, Rice SJ, Baldo GJ, Haspel HC, Mathias RT. Ion, water and neutral solute transport in Xenopus oocytes expressing frog lens MIP. Exp Eye Res. 1995 doi: 10.1016/s0014-4835(05)80129-0. in press. [DOI] [PubMed] [Google Scholar]
- 48.Weaver CD, Shomer NH, Louis CF, Roberts DM. Nodulin 26, a nodule-specific symbiosome membrane protein from soybean, is an ion channel. J Biol Chem. 1994;269:17858–17862. [PubMed] [Google Scholar]
- 49.You G, Smith CP, Kanai Y, Lee WS, Stelzner M, Hediger MA. Cloning and characterization of the vasopressin-regulated urea transporter. Nature. 1993;365:844–847. doi: 10.1038/365844a0. [DOI] [PubMed] [Google Scholar]
- 50.Olives B, Neau P, Bailly P, Hediger MA, Rousselet G, Cartron JP, Ripoche P. Cloning and functional expression of a urea transporter from human bone marrow cells. J Biol Chem. 1994;269:31649–31652. of special interest. [PubMed] [Google Scholar]; A red cell urea transporter related to the kidney urea transporter [49] was isolated by homology cloning.
- 51.Macey RI, Youssef LW. Osmotic stability of red cells in renal circulation requires rapid urea transport. Am J Physiol. 1988;254:C669–C674. doi: 10.1152/ajpcell.1988.254.5.C669. [DOI] [PubMed] [Google Scholar]
- 52.Maurel C, Reizer J, Schroeder I, Chrispeels MJ, Saier MH. Functional characterization of the Escherichia coli glycerol facilitator, GlpF, in Xenopus oocytes. J Biol Chem. 1994;269:11869–11872. [PubMed] [Google Scholar]
- 53.Denker BM, Smith BL, Kuhajda FP, Agre P. Identification, purification, and partial characterization of a novel Mr 28,000 integral membrane protein from erythrocytes and renal tubules. J Biol Chem. 1988;263:15634–15642. [PubMed] [Google Scholar]
- 54.Sabolic I, Valenti G, Verbavatz JM, Van Hoek AN, Verkman AS, Ausiello DA, Brown D. Localization of the CHIP28 water channel in rat kidney. Am J Physiol. 1992;263:C1225–C1233. doi: 10.1152/ajpcell.1992.263.6.C1225. [DOI] [PubMed] [Google Scholar]
- 55.Nielsen S, Pallone TL, Smith BL, Christensen EI, Agre P, Maunsbach AB. Aquaporin-1 water channels in short and long loop descending thin limbs and in descending vasa recta in rat kidney. Am J Physiol. 1995 doi: 10.1152/ajprenal.1995.268.6.F1023. in press. [DOI] [PubMed] [Google Scholar]
- 56.Maeda Y, Smith BL, Agre P, Knepper MA. Quantification of Aquaporin-CHIP water channel protein in microdissected renal tubules by fluorescence-based ELISA. J Clin Invest. 1995;95:422–428. doi: 10.1172/JCI117672. of special interest. [DOI] [PMC free article] [PubMed] [Google Scholar]; Calculations based on measurements of AQP1 abundance show that the protein can explain the water permeability of the proximal nephron.
- 57.Nielsen S, Smith BL, Christensen EI, Agre P. Distribution of Aquaporin CHIP in secretory and resorptive epithelia and capillary endothelia. Proc Natl Acad Sci USA. 1993;90:7275–7279. doi: 10.1073/pnas.90.15.7275. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 58.Stamer WD, Snyder RW, Smith BL, Agre P, Regan JW. Localization of aquaporin CHIP in the human eye: implications in the pathogenesis of glaucoma and other disorders of ocular fluid balance. Invest Ophthalmol Vis Sci. 1994;35:3867–3872. [PubMed] [Google Scholar]
- 59.Roberts SK, Yano M, Ueno Y, Pham L, Alpini G, Agre P, LaRusso NF. Cholangiocytes express the aquaporin CHIP and transport water via a channel-mediated mechanism. Proc Natl Acad Sci USA. 1994;91:13009–13013. doi: 10.1073/pnas.91.26.13009. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 60.Bondy C, Chin E, Smith BL, Preston GM, Agre P. Developmental gene expression and tissue distribution of the CHIP28 water-channel protein. Proc Natl Acad Sci USA. 1993;90:4500–4504. doi: 10.1073/pnas.90.10.4500. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 61.Stankovic KM, Adams JC, Brown D. Immunolocalization of aquaporin CHIP in the guinea pig inner ear. Am J Physiol. 1995 doi: 10.1152/ajpcell.1995.269.6.C1450. in press. [DOI] [PubMed] [Google Scholar]
- 62.Brown D, Verbavatz JM, Valenti B, Lui B, Sabolic I. Localization of the CHIP28 water channel in reabsorptive segments of the rat male reproductive tract. Eur J Cell Biol. 1993;61:264–273. [PubMed] [Google Scholar]
- 63.Folkesson HG, Matthay MA, Hasegawa H, Kheradmand F, Verkman AS. Transcellular water transport in lung alveolar epithelium through mercury-sensitive water channels. Proc Natl Acad Sci USA. 1994;91:4970–4974. doi: 10.1073/pnas.91.11.4970. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 64.Hasegawa H, Lian SC, Finkbeiner WE, Verkman AS. Extrarenal tissue distribution of CHIP28 water channels by in situ hybridization and antibody staining. Am J Physiol. 1994;266:C893–C903. doi: 10.1152/ajpcell.1994.266.4.C893. [DOI] [PubMed] [Google Scholar]
- 65.Valenti G, Verbavatz JM, Sabolic I, Ausiello DA, Verkman AS, Brown D. A basolateral CHIP28/MIP26-related protein (BLIP) in kidney principal cells and gastric parietal cells. Am J Physiol. 1994;267:C812–C820. doi: 10.1152/ajpcell.1994.267.3.C812. [DOI] [PubMed] [Google Scholar]
- 66.Shiels A, Griffin CS. Aberrant expression of the gene for lens major intrinsic protein the CAT mouse. Curr Eye Res. 1993;12:913–921. doi: 10.3109/02713689309020398. [DOI] [PubMed] [Google Scholar]
- 67.Nielsen S, DiGiovanni SR, Christensen EI, Knepper MA, Harris HW. Cellular and subcellular immunolocalization of vasopressin-regulated water channel in rat kidney. Proc Natl Acad Sci USA. 1993;90:11663–11667. doi: 10.1073/pnas.90.24.11663. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 68.Van-Lieburg AF, Verdijk MA, Knoers VV, Van-Essen AJ, Proesmans W, Mallmann R, Monnens LA, Van-Oost BA, Van Os CH, Deen PM. Patients with autosomal nephrogenic diabetes insipidus homozygous for mutations in the aquaporin-2 water-channel gene. Am J Hum Genet. 1994;55:648–652. [PMC free article] [PubMed] [Google Scholar]
- 69.Deen PMT, Croes H, Van Aubel AMH, Ginsel LA, Van Os CH. Water channels encoded by mutant aquaporin-2 genes in nephrogenic diabetes insipidus are impaired in their cellular routing. J Clin Invest. 1995;95:2291–2296. doi: 10.1172/JCI117920. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 70.DiGiovanni SR, Nielsen S, Christensen EI, Knepper MA. Regulation of collecting duct water channel expression by vasopressin in Brattleboro rat. Proc Natl Acad Sci USA. 1994;91:8984–8988. doi: 10.1073/pnas.91.19.8984. of special interest. [DOI] [PMC free article] [PubMed] [Google Scholar]; In addition to vesicles trafficking, vasopressin was shown to regulate protein synthesis.
- 71.Marples D, Christensen S, Christensen EI, Nielsen S. Lithium-induced down regulation of aquaporin-2 water channel expression in rat kidney medulla. J Clin Invest. 1995;95:1838–1845. doi: 10.1172/JCI117863. of special interest. [DOI] [PMC free article] [PubMed] [Google Scholar]; Markedly reduced expression of AQP2 is identified in an a murine model of nephrogenic diabetes insipidus.
- 72.Wade JB. Role of membrane traffic in the water and Na responses to vasopressin. Semin Nephrol. 1994;14:322–332. [PubMed] [Google Scholar]
- 73.Sabolic I, Katsura T, Verbavatz JM, Brown D. The AQP2 water channel: effect of vasopressin treatment microtubule disruption, and distribution in neonatal rats. J Membr Biol. 1995;143:165–175. doi: 10.1007/BF00233445. [DOI] [PubMed] [Google Scholar]
- 74.Nielsen S, Chou CL, Marples D, Christensen EI, Kishore BK, Knepper MA. Vasopressin increases water permeability of kidney collecting duct by inducing translocation of aquaporin-CD water channels to plasma membrane. Proc Natl Acad Sci USA. 1995;92:1013–1017. doi: 10.1073/pnas.92.4.1013. of special interest. [DOI] [PMC free article] [PubMed] [Google Scholar]; This reports the molecular and physiological consequences on the intracellular localization of AQP2-containing vesicles in isolated kidney collecting ducts treated with vasopressin.
- 75.Marples D, Knepper MA, Christensen EI, Nielsen S. Redistribution of Aquaporin-2 water channels induced by vasopressin in rat kidney inner medullary collecting duct. Am J Physiol. 1995 doi: 10.1152/ajpcell.1995.269.3.C655. in press. [DOI] [PubMed] [Google Scholar]
- 76.Jo I, Harris HW, Amedt-Raduege AM, Majewski RR, Hammond TG. Rat kidney papilla contains abundant synaptobrevin protein that participates in the fusion of antidiuretic hormone (ADH) water channel-containing endosomes in vitro. Proc Natl Acad Sci USA. 1995;92:1876–1880. doi: 10.1073/pnas.92.6.1876. of special interest. [DOI] [PMC free article] [PubMed] [Google Scholar]; A cellular component of membrane targeting is identified on AQP2-containing vesicles.
- 77.Nielsen S, Marples D, Birn H, Mihtashami M, Dalby NO, Trimble W, Knepper M. Expression of VAMP2-like protein in kidney collecting duct intracellular vesicles: colocalization with Aquaporin-2 water channels. J Clin Invest. 1995 doi: 10.1172/JCI118229. of outstanding interest. [DOI] [PMC free article] [PubMed] [Google Scholar]; The presence of VAMP2 and AQP2 vesicles was established by extensive immunoblotting, immunohistochemistry, and double-labeling immunogold electron microscopy and immuno-isolations.
- 78.Kuwahara M, Fushimi K, Terada Y, Bai L, Marumo F, Sasaki S. cAMP-dependent phosphorylation stimulates water permeability of Aquaporin-collecting duct water channel protein expressed in Xenopus oocytes. J Biol Chem. 1995;270:10384–10387. doi: 10.1074/jbc.270.18.10384. of special interest. [DOI] [PubMed] [Google Scholar]; Demonstration that cAMP-induced phosphorylation of AQP2 is correlated with an incremental increase in osmotic water permeability in the oocyte expression system.
- 79.Katsura T, Verbavatz JM, Farinas J, Ma T, Ausiello DA, Verkman AS, Brown D. Constitutive and regulated membrane expression of aquaporin-1 and aquaporin-2 water channels in stably transfected LLC-PK1 cells. Proc Natl Acad Sci USA. 1995 doi: 10.1073/pnas.92.16.7212. of special interest. [DOI] [PMC free article] [PubMed] [Google Scholar]; Targeting of AQP2-myc recombinant proteins to basolateral plasma membranes of a renal tubule cell line is shown in response to cAMP stimulation.
- 80.Lande MB, Jo I, Zeidel ML, Somers M, Harris HW. Phosphorylation of Aquaporin-2 does not alter the membrane water permeability of rat papillary water channel-containing vesicles. J Biol Chem. 1995 doi: 10.1074/jbc.271.10.5552. in press. [DOI] [PubMed] [Google Scholar]
- 81.Ecelbarger C, Terris J, Frindt G, Echevarria M, Marples D, Nielsen S, Knepper MA. Aquaporin-3 water channel localization and regulation in rat kidney. Am J Physiol. 1995 doi: 10.1152/ajprenal.1995.269.5.F663. in press. [DOI] [PubMed] [Google Scholar]
- 82.Frigeri A, Gropper MA, Kawashima K, Brown D, Verkman AS. Localization of MIWC and GLIP water channel homologs in neuromuscular epithelia and glandular tissues. J Cell Sci. 1995 doi: 10.1242/jcs.108.9.2993. in press. [DOI] [PubMed] [Google Scholar]
- 83.Oliet SH, Bourque CW. Mechanosensitive channels transduce osmosensitivity in supraoptic neurons. Nature. 1993;364:341–343. doi: 10.1038/364341a0. [DOI] [PubMed] [Google Scholar]
- 84.Terris J, Ecelbarger C, Marples D, Knopper MA, Nielsen S. Distribution of Aquaporin-4 water channel expression within rat kidney. Am J Physiol. 1995 doi: 10.1152/ajprenal.1995.269.6.F775. in press. [DOI] [PubMed] [Google Scholar]