Protein Kinase C-α Activity Modulates Transepithelial Permeability and Cell Junctions in the LLC-PK1 Epithelial Cell Line*
- Dan Rosson‡§,
- Thomas G. O’Brien‡,
- Jennifer A. Kampherstein‡,
- Zoltan Szallasi¶‖,
- Krisztina Bogi¶,
- Peter M. Blumberg¶ and
- James M. Mullin‡
- From the ‡Lankenau Medical Research Center, Wynnewood, Pennsylvania 19096-3411 and the ¶Laboratory of Cellular Carcinogenesis and Tumor Promotion, NCI, National Institutes of Health, Bethesda, Maryland 20892-4255
Abstract
Modulation of protein kinase C (PKC) by 12-O-tetradecanoylphorbol-13-acetate (TPA) disrupts the cell-cell junctions of the epithelial cell line LLC-PK1. To examine the role of specific PKC isoforms in this process we have created modified LLC-PK1 subclones that express wild-type and dominant negative versions of PKC-α under control of the tetracycline-responsive expression system. Overexpression of wild-type PKC-α rendered the cells more sensitive to the effects of TPA on transepithelial permeability as measured by loss of transepithelial resistance across the cell sheet. Conversely, expression of a dominant negative PKC-α rendered the cells more resistant to the effects of TPA as measured both by loss of transepithelial resistance as well as cell scattering. The properties of both subclones could be modulated by the addition of tetracycline, which suppressed the effect of the exogenous genes. These results indicate that the α isoform of PKC is at least one of the isoforms that regulate tight junctions and other cell-cell junctions of LLC-PK1 epithelia.
Footnotes
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↵* This work was supported by National Institutes of Health Grants CA36353 (to T. G. O.) and CA48121 (to J. M. M.) from the NCI.The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
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↵§ To whom correspondence should be addressed: Lankenau Medical Research Center, 100 Lancaster Ave., Wynnewood, PA 19096-3411. Tel.: 610-645-3420; Fax: 610-645-2205.
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↵‖ Present address: Dept. of Pharmacology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814.
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↵1 The abbreviations used are: TPA, 12-O-tetradecanoylphorbol-13-acetate; TER, transepithelial resistance; PKC, protein kinase C; tTA, tetracycline-responsive transactivating protein.
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- Received February 18, 1997.
- Revision received March 26, 1997.
