Integrin expression in colon cancer cells is regulated by the cytoplasmic domain of the β6 integrin subunit

Abstract

We have previously reported that the αvβ6 integrin upregulates its own expression in a protein kinase C-dependent manner with increasing cell density. The wild-type β6 integrin subunit has also been shown to promote tumour growth in vivo and its growth-enhancing effect is regulated by both a MAP kinase binding motif on β6 and the II amino acid C-terminal cytoplasmic extension unique to the β6 subunit. Herein, we show that the II amino acid cytoplasmic extension is essential for the cell density-dependent increase in β6 expression and that the II amino acid tail exerts a dominant negative effect on cell density- and PKC-mediated β5 expression in αvβ6-expressing colon cancer cells. Cells that ..