Epithelial integrins.

We have undertaken the study of integrins specifically or predominantly expressed in epithelial cells, as they may be involved in establishing and maintaining properties peculiar to epithelia, such as polarization and morphogenetic movements. We describe here recent results regarding two such integrins. One of these contains the novel beta chain, beta 6, whose structure was deduced from cDNA clones. Some initial results on distribution and possible alpha chain associated to beta 6 are discussed. Structural data are then summarized on another epithelial integrin, alpha 6 beta 4. The alpha 6 subunit and a variant form of the beta 4 subunit were recently cloned in our laboratory. Adhesion assay results indicate that alpha 6 beta 4 may mediate attachment of epithelial cells to basement membranes.