AJP - Cell Physiology, Vol 262, Issue 2 C461-C469, Copyright © 1992 by American Physiological Society

ARTICLES

Detection of the tight junction-associated protein ZO-1 in astrocytes and other nonepithelial cell types

A. G. Howarth, M. R. Hughes and B. R. Stevenson
Department of Anatomy and Cell Biology, University of Alberta, Edmonton, Canada.

ZO-1 is a high molecular mass phosphoprotein peripherally associated with the cytoplasmic surface of tight junctions in epithelial and endothelial cells. We report here that ZO-1 is also present in several nonepithelial cell types in vitro that are not believed to form tight junctions, including primary cultures of astrocytes, Schwann cells, and dermal fibroblasts and the C6 glioma, S-180 (sarcoma), and P3 myeloma cell lines. Immunoblots of cell extracts probed with a ZO-1-specific monoclonal antibody reveal a single band that comigrates with ZO-1 from rodent epithelial cells at 225 kDa. In addition, these cells contain a single mRNA species of identical size to that previously reported for ZO-1 in epithelial tissues, as determined by Northern blots probed with a partial ZO-1 cDNA. Immunofluorescence microscopy demonstrates diverse ZO-1 distributions in these cells. In astrocytes, identified by the presence of glial fibrillary acidic protein, ZO-1 is localized at discrete sites of cell-cell contact as well as within the cell cytoplasm. In contrast, S-180 cells display diffuse staining at the cell periphery and within the cytoplasm. Dermal fibroblasts show no staining above background, although ZO-1 was detected on immunoblots of fibroblast cell extracts. Immunofluorescence staining of frozen sections of mouse brain demonstrates no detectable ZO-1 immunoreactivity outside blood vessels where endothelial cell tight junctions of the blood-brain barrier are located. These studies suggest that, although ZO-1 is found to be associated with the tight junction, it has a broader distribution than previously recognized.

This article has been cited by other articles:

				E. E. Schneeberger and R. D. Lynch The tight junction: a multifunctional complex Am J Physiol Cell Physiol, June 1, 2004; 286(6): C1213 - C1228. [Abstract] [Full Text] [PDF]

				M. M. Thi, T. Kojima, S. C. Cowin, S. Weinbaum, and D. C. Spray Fluid shear stress remodels expression and function of junctional proteins in cultured bone cells Am J Physiol Cell Physiol, February 1, 2003; 284(2): C389 - C403. [Abstract] [Full Text] [PDF]

				E. S. Wittchen, J. Haskins, and B. R. Stevenson Exogenous Expression of the Amino-terminal Half of the Tight Junction Protein ZO-3 Perturbs Junctional Complex Assembly J. Cell Biol., November 13, 2000; 151(4): 825 - 836. [Abstract] [Full Text] [PDF]

				S. W. Ryeom, D. Paul, and D. A. Goodenough Truncation Mutants of the Tight Junction Protein ZO-1 Disrupt Corneal Epithelial Cell Morphology Mol. Biol. Cell, May 1, 2000; 11(5): 1687 - 1696. [Abstract] [Full Text]

				M. Cordenonsi, F. D'Atri, E. Hammar, D. A.D. Parry, J. Kendrick-Jones, D. Shore, and S. Citi Cingulin Contains Globular and Coiled-coil Domains and Interacts with ZO-1, ZO-2, ZO-3, and Myosin J. Cell Biol., December 27, 1999; 147(7): 1569 - 1582. [Abstract] [Full Text] [PDF]

				E. S. Wittchen, J. Haskins, and B. R. Stevenson Protein Interactions at the Tight Junction. ACTIN HAS MULTIPLE BINDING PARTNERS, AND ZO-1 FORMS INDEPENDENT COMPLEXES WITH ZO-2 AND ZO-3 J. Biol. Chem., December 3, 1999; 274(49): 35179 - 35185. [Abstract] [Full Text] [PDF]

				L. D. Adams, J. M. Lemire, and S. M. Schwartz A Systematic Analysis of 40 Random Genes in Cultured Vascular Smooth Muscle Subtypes Reveals a Heterogeneity of Gene Expression and Identifies the Tight Junction Gene Zonula Occludens 2 as a Marker of Epithelioid "Pup" Smooth Muscle Cells and a Participant in Carotid Neointimal Formation Arterioscler. Thromb. Vasc. Biol., November 1, 1999; 19(11): 2600 - 2608. [Abstract] [Full Text] [PDF]

				A. S. Fanning, B. J. Jameson, L. A. Jesaitis, and J. M. Anderson The Tight Junction Protein ZO-1 Establishes a Link between the Transmembrane Protein Occludin and the Actin Cytoskeleton J. Biol. Chem., November 6, 1998; 273(45): 29745 - 29753. [Abstract] [Full Text] [PDF]

				Y. Izumi, T. Hirose, Y. Tamai, S.-i. Hirai, Y. Nagashima, T. Fujimoto, Y. Tabuse, K. J. Kemphues, and S. Ohno An Atypical PKC Directly Associates and Colocalizes at the Epithelial Tight Junction with ASIP, a Mammalian Homologue of Caenorhabditis elegans Polarity Protein PAR-3 J. Cell Biol., October 5, 1998; 143(1): 95 - 106. [Abstract] [Full Text] [PDF]

				J. Haskins, L. Gu, E. S. Wittchen, J. Hibbard, and B. R. Stevenson ZO-3, a Novel Member of the MAGUK Protein Family Found at the Tight Junction, Interacts with ZO-1 and Occludin J. Cell Biol., April 6, 1998; 141(1): 199 - 208. [Abstract] [Full Text] [PDF]

				T. Yamamoto, N. Harada, K. Kano, S.-i. Taya, E. Canaani, Y. Matsuura, A. Mizoguchi, C. Ide, and K. Kaibuchi The Ras Target AF-6 Interacts with ZO-1 and Serves as a Peripheral Component of Tight Junctions in Epithelial Cells J. Cell Biol., November 3, 1997; 139(3): 785 - 795. [Abstract] [Full Text] [PDF]

				H. Sakurai, E. J. Barros, T. Tsukamoto, J. Barasch, and S. K. Nigam An in vitro tubulogenesis system using cell lines derived from the embryonic kidney shows dependence on multiple soluble growth factors PNAS, June 10, 1997; 94(12): 6279 - 6284. [Abstract] [Full Text] [PDF]

				S. N. Mattagajasingh, S.-C. Huang, J. S. Hartenstein, and E. J. Benz Jr. Characterization of the Interaction between Protein 4.1R and ZO-2. A POSSIBLE LINK BETWEEN THE TIGHT JUNCTION AND THE ACTIN CYTOSKELETON J. Biol. Chem., September 22, 2000; 275(39): 30573 - 30585. [Abstract] [Full Text] [PDF]