• We are sorry, but NCBI web applications do not support your browser and may not function properly. More information
Logo of embojLink to Publisher's site
EMBO J. Jul 1, 1994; 13(13): 2985–2993.
PMCID: PMC395186

The three-dimensional structure of human erythrocyte aquaporin CHIP.


Water-permeable membranes of several plant and mammalian tissues contain specific water channel proteins, the 'aquaporins'. The best characterized aquaporin is CHIP, a 28 kDa red blood cell channel-forming integral protein. Isolated CHIP and Escherichia coli lipids may be assembled into 2-D crystals for structural analyses. Here we present (i) a structural characterization of the solubilized CHIP oligomers, (ii) projections of CHIP arrays after negative staining or metal-shadowing, and (iii) the 3-D structure at 1.6 nm resolution. Negatively stained CHIP oligomers exhibited a side length of 6.9 nm with four-fold symmetry, and a mass of 202 +/- 3 kDa determined by scanning transmission electron microscopy. Reconstituted into lipid bilayers, CHIP formed 2-D square lattices with unit cell dimensions a = b = 9.6 nm and a p422(1) symmetry. The 3-D map revealed that CHIP tetramers contain central stain-filled depressions about the fourfold axis. These cavities extend from both sides into the transbilayer domain of the molecule leaving only a thin barrier to be penetrated by the water pores. Although CHIP monomers behave as independent pores, we propose that their particular structure requires tetramerization for stable integration into the bilayer.

Full text

Full text is available as a scanned copy of the original print version. Get a printable copy (PDF file) of the complete article (4.2M), or click on a page image below to browse page by page. Links to PubMed are also available for Selected References.

Images in this article

Selected References

These references are in PubMed. This may not be the complete list of references from this article.
  • 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 U S A. 1991 Dec 15;88(24):11110–11114. [PMC free article] [PubMed]
  • Preston GM, Carroll TP, Guggino WB, Agre P. Appearance of water channels in Xenopus oocytes expressing red cell CHIP28 protein. Science. 1992 Apr 17;256(5055):385–387. [PubMed]
  • Preston GM, Jung JS, Guggino WB, Agre P. The mercury-sensitive residue at cysteine 189 in the CHIP28 water channel. J Biol Chem. 1993 Jan 5;268(1):17–20. [PubMed]
  • 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 Jan 21;269(3):1668–1673. [PubMed]
  • Reizer J, Reizer A, Saier MH., Jr 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(3):235–257. [PubMed]
  • Sabolić 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 Dec;263(6 Pt 1):C1225–C1233. [PubMed]
  • Saxton WO, Baumeister W. The correlation averaging of a regularly arranged bacterial cell envelope protein. J Microsc. 1982 Aug;127(Pt 2):127–138. [PubMed]
  • Smith BL, Agre P. Erythrocyte Mr 28,000 transmembrane protein exists as a multisubunit oligomer similar to channel proteins. J Biol Chem. 1991 Apr 5;266(10):6407–6415. [PubMed]
  • Smith BL, Baumgarten R, Nielsen S, Raben D, Zeidel ML, Agre P. Concurrent expression of erythroid and renal aquaporin CHIP and appearance of water channel activity in perinatal rats. J Clin Invest. 1993 Oct;92(4):2035–2041. [PMC free article] [PubMed]
  • van Hoek AN, Hom ML, Luthjens LH, de Jong MD, Dempster JA, van Os CH. Functional unit of 30 kDa for proximal tubule water channels as revealed by radiation inactivation. J Biol Chem. 1991 Sep 5;266(25):16633–16635. [PubMed]
  • Van Hoek AN, Wiener M, Bicknese S, Miercke L, Biwersi J, Verkman AS. Secondary structure analysis of purified functional CHIP28 water channels by CD and FTIR spectroscopy. Biochemistry. 1993 Nov 9;32(44):11847–11856. [PubMed]
  • Verbavatz JM, Brown D, Sabolić 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 Nov;123(3):605–618. [PMC free article] [PubMed]
  • Walz T, Smith BL, Zeidel ML, Engel A, Agre P. Biologically active two-dimensional crystals of aquaporin CHIP. J Biol Chem. 1994 Jan 21;269(3):1583–1586. [PubMed]
  • Weiss MS, Abele U, Weckesser J, Welte W, Schiltz E, Schulz GE. Molecular architecture and electrostatic properties of a bacterial porin. Science. 1991 Dec 13;254(5038):1627–1630. [PubMed]
  • Wrigley NG. The lattice spacing of crystalline catalase as an internal standard of length in electron microscopy. J Ultrastruct Res. 1968 Sep;24(5):454–464. [PubMed]
  • Zeidel ML, Ambudkar SV, Smith BL, Agre P. Reconstitution of functional water channels in liposomes containing purified red cell CHIP28 protein. Biochemistry. 1992 Aug 25;31(33):7436–7440. [PubMed]
  • Zeidel ML, Nielsen S, Smith BL, Ambudkar SV, Maunsbach AB, Agre P. Ultrastructure, pharmacologic inhibition, and transport selectivity of aquaporin channel-forming integral protein in proteoliposomes. Biochemistry. 1994 Feb 15;33(6):1606–1615. [PubMed]
  • Aebi U, Smith PR, Dubochet J, Henry C, Kellenberger E. A study of the structure of the T-layer of Bacillus brevis. J Supramol Struct. 1973;1(6):498–522. [PubMed]
  • 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 Oct;265(4 Pt 2):F463–F476. [PubMed]
  • Berriman J, Leonard KR. Methods for specimen thickness determination in electron microscopy. II. Changes in thickness with dose. Ultramicroscopy. 1986;19(4):349–366. [PubMed]
  • 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 U S A. 1993 May 15;90(10):4500–4504. [PMC free article] [PubMed]
  • Cowan SW, Schirmer T, Rummel G, Steiert M, Ghosh R, Pauptit RA, Jansonius JN, Rosenbusch JP. Crystal structures explain functional properties of two E. coli porins. Nature. 1992 Aug 27;358(6389):727–733. [PubMed]
  • 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 Oct 25;263(30):15634–15642. [PubMed]
  • Ford RC, Hefti A, Engel A. Ordered arrays of the photosystem I reaction centre after reconstitution: projections and surface reliefs of the complex at 2 nm resolution. EMBO J. 1990 Oct;9(10):3067–3075. [PMC free article] [PubMed]
  • Gorin MB, Yancey SB, Cline J, Revel JP, Horwitz J. The major intrinsic protein (MIP) of the bovine lens fiber membrane: characterization and structure based on cDNA cloning. Cell. 1984 Nov;39(1):49–59. [PubMed]
  • Horwitz J, Bok D. Conformational properties of the main intrinsic polypeptide (MIP26) isolated from lens plasma membranes. Biochemistry. 1987 Dec 15;26(25):8092–8098. [PubMed]
  • Hovmöller S, Slaughter M, Berriman J, Karlsson B, Weiss H, Leonard K. Structural studies of cytochrome reductase. Improved membrane crystals of the enzyme complex and crystallization of a subcomplex. J Mol Biol. 1983 Apr 5;165(2):401–406. [PubMed]
  • Jap BK, Zulauf M, Scheybani T, Hefti A, Baumeister W, Aebi U, Engel A. 2D crystallization: from art to science. Ultramicroscopy. 1992 Oct;46(1-4):45–84. [PubMed]
  • 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 May 20;269(20):14648–14654. [PubMed]
  • Macey RI, Farmer RE. Inhibition of water and solute permeability in human red cells. Biochim Biophys Acta. 1970 Jul 7;211(1):104–106. [PubMed]
  • Mannella CA. Mitochondrial outer membrane channel (VDAC, porin) two-dimensional crystals from Neurospora. Methods Enzymol. 1986;125:595–610. [PubMed]
  • Nielsen S, Smith BL, Christensen EI, Agre P. Distribution of the aquaporin CHIP in secretory and resorptive epithelia and capillary endothelia. Proc Natl Acad Sci U S A. 1993 Aug 1;90(15):7275–7279. [PMC free article] [PubMed]
  • 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 Jan;120(2):371–383. [PMC free article] [PubMed]

Articles from The EMBO Journal are provided here courtesy of The European Molecular Biology Organization


Related citations in PubMed

See reviews...See all...

Cited by other articles in PMC

See all...


Recent Activity

Your browsing activity is empty.

Activity recording is turned off.

Turn recording back on

See more...