Vinculin Is Associated with the E-cadherin Adhesion Complex*
- From the ‡Department of Surgery, Memorial Sloan-Kettering Cancer Center, New York, New York 10021 and the¶Department of Pathology, Yale University School of Medicine, New Haven, Connecticut 06510
Abstract
Cadherins mediate calcium-dependent cell-cell adhesion, and this activity is regulated by cytoplasmic interactions between cadherins, catenins, and the actin-based cytoskeleton. α-Catenin plays a critical role in the transmembrane anchorage of cadherins, and deletion of α-catenin has been shown to inactivate cadherin-mediated adhesion, resulting in a nonadhesive phenotype. Here we show that serum starvation increases E-cadherin expression and induces E-cadherin-dependent adhesion in the MDA-MB-468 breast cancer cell line. This adhesion occurred despite a lack of α-catenin expression, which was caused by mutations in the α-catenin gene. Coprecipitation analysis suggests that this adhesion may be mediated by cytoplasmic connections from cadherins to the cytoskeleton involving vinculin. A high level of vinculin associated with E-cadherin immunoprecipitates was observed in MDA-MB-468 cells. In contrast, vinculin was not detected in E-cadherin complexes in the A431 and MCF-7 epithelial carcinoma cell lines, which express α-catenin. However, in reciprocal immunoprecipitations using anti-vinculin antibodies, E-cadherin associated strongly with vinculin in MDA-MB-468 cells and, to a lesser extent, in A431 and MCF-7 cells. These results suggest that both α-catenin and vinculin may be present in the adhesion complex. To test the hypothesis that vinculin associates with E-cadherin complexes via β-catenin, excess recombinant β-catenin or α-catenin fusion protein was added to MDA-MB-468 cell lysates. Both specifically inhibited the coprecipitation of E-cadherin with vinculin, suggesting competition for the same binding site. These results suggest that vinculin plays a role in the establishment or regulation of the cadherin-based cell adhesion complex by direct interaction with β-catenin.
Footnotes
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↵* This work was supported by the Department of Surgery and in part by a new investigator grant from the William and Catherine Weldon Donaghue Foundation for Medical Research (to D. L. R.).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. Present address: The Derald H. Ruttenberg Cancer Center, Mount Sinai Medical Center, One Gustave L. Levy-Place, Box 1130, New York, NY ID029. Tel.: 212-824-8168; Fax: 212-987-2240.
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↵1 The abbreviations used are: EGF, epidermal growth factor; RT-PCR, reverse transcription-polymerase chain reaction; GST, glutathione S-transferase.
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- Received June 27, 1997.
- Revision received October 2, 1997.
