Localization of mLin-7 at nectin-based cell-cell junctions.

In C. elegans, lin-7 as well as lin-2/lin-10 is involved in the proper localization of the LET-23 receptor tyrosine kinase that regulates vulval induction. The mammalian homologue, mLin-7, forms a ternary complex with the mammalian homologues of LIN-2 and LIN-10 and localizes at cell-cell junctions in epithelial cells, but the mechanism of this localization of mLin-7 is unknown. Nectin is an immunoglobulin-like cell-cell adhesion molecule that is involved in organization of adherens and tight junctions in epithelial cells. Nectin is indirectly associated with the cadherin-catenin system and the actin cytoskeleton through afadin, an actin filament-binding protein. We showed here that mLin-7 localized at the nectin-based cell-cell junctions. This localization of mLin-7 required the interaction of nectin with afadin, but not the cadherin-catenin system or the actin cytoskeleton. mLin-7 did not directly interact with nectin or afadin. The results indicate that mLin-7 localizes at cell-cell junctions through the nectin-afadin system.