Abstract
ZO-1, originally identified by mAb techniques, is the first protein shown to be specifically associated with the tight junction. Here we describe and compare the physical characteristics of ZO-1 from mouse liver and the Madin-Darby canine kidney (MDCK) epithelial cell line. The ZO-1 polypeptide has an apparent size of 225 kD in mouse tissues and 210 kD in canine-derived MDCK cells as determined by SDS- PAGE/immunoblot analysis. ZO-1 from both sources is optimally solubilized from isolated plasma membranes by either 6 M urea or high pH conditions; partial solubilization occurs with 0.3 M KCl. The nonionic detergents, Triton X-100 and octyl-beta-D-glucopyranoside, do not solubilize ZO-1. These solubility properties indicate that ZO-1 is a peripherally associated membrane protein. ZO-1 was purified to electrophoretic homogeneity from [35S]methionine metabolically labeled MDCK cells by a combination of gel filtration and immunoaffinity chromatography. Purified ZO-1 has an s20,w of 5.3 and Stokes radius of 8.6 nm. These values suggest that purified ZO-1 is an asymmetric monomeric molecule. Corresponding values for mouse liver ZO-1, characterized in impure protein extracts, were 6 s20,w and 9 nm. ZO-1 was shown to be a phosphoprotein in MDCK cells metabolically labeled with [32P]orthophosphate; analysis of phosphoamino acids from purified ZO-1 revealed only phosphoserine. ZO-1 epitope number was determined by Scatchard analysis of competitive and saturable binding of two different 125I-mAbs to SDS-solubilized proteins from liver and MDCK cells immobilized on nitrocellulose. Saturation binding occurs at 26 ng mAb/mg liver and 63 ng/mg of MDCK cell protein. This is equivalent to 30,000 ZO-1 molecules per MDCK cell assuming a single epitope/ZO-1 molecule.
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- Ackers G. K. Analytical gel chromatography of proteins. Adv Protein Chem. 1970;24:343–446. doi: 10.1016/s0065-3233(08)60245-4. [DOI] [PubMed] [Google Scholar]
- Balcarova-Ständer J., Pfeiffer S. E., Fuller S. D., Simons K. Development of cell surface polarity in the epithelial Madin-Darby canine kidney (MDCK) cell line. EMBO J. 1984 Nov;3(11):2687–2694. doi: 10.1002/j.1460-2075.1984.tb02194.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Cereijido M., Robbins E. S., Dolan W. J., Rotunno C. A., Sabatini D. D. Polarized monolayers formed by epithelial cells on a permeable and translucent support. J Cell Biol. 1978 Jun;77(3):853–880. doi: 10.1083/jcb.77.3.853. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Claude P., Goodenough D. A. Fracture faces of zonulae occludentes from "tight" and "leaky" epithelia. J Cell Biol. 1973 Aug;58(2):390–400. doi: 10.1083/jcb.58.2.390. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Cooper J. A., Sefton B. M., Hunter T. Detection and quantification of phosphotyrosine in proteins. Methods Enzymol. 1983;99:387–402. doi: 10.1016/0076-6879(83)99075-4. [DOI] [PubMed] [Google Scholar]
- Diamond J. M. Twenty-first Bowditch lecture. The epithelial junction: bridge, gate, and fence. Physiologist. 1977 Feb;20(1):10–18. [PubMed] [Google Scholar]
- Duffey M. E., Hainau B., Ho S., Bentzel C. J. Regulation of epithelial tight junction permeability by cyclic AMP. Nature. 1981 Dec 3;294(5840):451–453. doi: 10.1038/294451a0. [DOI] [PubMed] [Google Scholar]
- FARQUHAR M. G., PALADE G. E. Junctional complexes in various epithelia. J Cell Biol. 1963 May;17:375–412. doi: 10.1083/jcb.17.2.375. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Friend D. S., Gilula N. B. Variations in tight and gap junctions in mammalian tissues. J Cell Biol. 1972 Jun;53(3):758–776. doi: 10.1083/jcb.53.3.758. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Gonzalez-Mariscal L., Chávez de Ramírez B., Cereijido M. Tight junction formation in cultured epithelial cells (MDCK). J Membr Biol. 1985;86(2):113–125. doi: 10.1007/BF01870778. [DOI] [PubMed] [Google Scholar]
- Hartree E. F. Determination of protein: a modification of the Lowry method that gives a linear photometric response. Anal Biochem. 1972 Aug;48(2):422–427. doi: 10.1016/0003-2697(72)90094-2. [DOI] [PubMed] [Google Scholar]
- Horwitz A., Duggan K., Buck C., Beckerle M. C., Burridge K. Interaction of plasma membrane fibronectin receptor with talin--a transmembrane linkage. Nature. 1986 Apr 10;320(6062):531–533. doi: 10.1038/320531a0. [DOI] [PubMed] [Google Scholar]
- Immunochemical techniques. Part B. Methods Enzymol. 1981;73(Pt B):1–739. [PubMed] [Google Scholar]
- Jones J. C., Goldman R. D. Intermediate filaments and the initiation of desmosome assembly. J Cell Biol. 1985 Aug;101(2):506–517. doi: 10.1083/jcb.101.2.506. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kuijpers G. A., Van Nooy I. G., Vossen M. E., Stadhouders A. M., Van Uyen A., De Pont J. J., Bonting S. L. Tight junctional permeability of the resting and carbachol stimulated exocrine rabbit pancreas. Histochemistry. 1985;83(3):257–264. doi: 10.1007/BF00953994. [DOI] [PubMed] [Google Scholar]
- Laemmli U. K. Cleavage of structural proteins during the assembly of the head of bacteriophage T4. Nature. 1970 Aug 15;227(5259):680–685. doi: 10.1038/227680a0. [DOI] [PubMed] [Google Scholar]
- MARTIN R. G., AMES B. N. A method for determining the sedimentation behavior of enzymes: application to protein mixtures. J Biol Chem. 1961 May;236:1372–1379. [PubMed] [Google Scholar]
- Madara J. L., Dharmsathaphorn K. Occluding junction structure-function relationships in a cultured epithelial monolayer. J Cell Biol. 1985 Dec;101(6):2124–2133. doi: 10.1083/jcb.101.6.2124. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Mazariegos M. R., Tice L. W., Hand A. R. Alteration of tight junctional permeability in the rat parotid gland after isoproterenol stimulation. J Cell Biol. 1984 May;98(5):1865–1877. doi: 10.1083/jcb.98.5.1865. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Ojakian G. K. Tumor promoter-induced changes in the permeability of epithelial cell tight junctions. Cell. 1981 Jan;23(1):95–103. doi: 10.1016/0092-8674(81)90274-9. [DOI] [PubMed] [Google Scholar]
- Pisam M., Ripoche P. Redistribution of surface macromolecules in dissociated epithelial cells. J Cell Biol. 1976 Dec;71(3):907–920. doi: 10.1083/jcb.71.3.907. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Powell D. W. Barrier function of epithelia. Am J Physiol. 1981 Oct;241(4):G275–G288. doi: 10.1152/ajpgi.1981.241.4.G275. [DOI] [PubMed] [Google Scholar]
- Stevenson B. R., Goodenough D. A. Zonulae occludentes in junctional complex-enriched fractions from mouse liver: preliminary morphological and biochemical characterization. J Cell Biol. 1984 Apr;98(4):1209–1221. doi: 10.1083/jcb.98.4.1209. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Stevenson B. R., Siliciano J. D., Mooseker M. S., Goodenough D. A. Identification of ZO-1: a high molecular weight polypeptide associated with the tight junction (zonula occludens) in a variety of epithelia. J Cell Biol. 1986 Sep;103(3):755–766. doi: 10.1083/jcb.103.3.755. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Towbin H., Staehelin T., Gordon J. Electrophoretic transfer of proteins from polyacrylamide gels to nitrocellulose sheets: procedure and some applications. Proc Natl Acad Sci U S A. 1979 Sep;76(9):4350–4354. doi: 10.1073/pnas.76.9.4350. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Vega-Salas D. E., Salas P. J., Gundersen D., Rodriguez-Boulan E. Formation of the apical pole of epithelial (Madin-Darby canine kidney) cells: polarity of an apical protein is independent of tight junctions while segregation of a basolateral marker requires cell-cell interactions. J Cell Biol. 1987 Apr;104(4):905–916. doi: 10.1083/jcb.104.4.905. [DOI] [PMC free article] [PubMed] [Google Scholar]
- van Meer G., Simons K. The function of tight junctions in maintaining differences in lipid composition between the apical and the basolateral cell surface domains of MDCK cells. EMBO J. 1986 Jul;5(7):1455–1464. doi: 10.1002/j.1460-2075.1986.tb04382.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- van Renswoude J., Kempf C. Purification of integral membrane proteins. Methods Enzymol. 1984;104:329–339. doi: 10.1016/s0076-6879(84)04099-4. [DOI] [PubMed] [Google Scholar]