A role for α- and β-catenins in bacterial uptake

摘要

Interaction of internalin with E-cadherin promotes entry of Listeris monocytogenes into human epithelial cells. This process requires actin cytoskeleton rearrangements. Here we show by using a series of stably transfected cell lines expressing E-cadherin vari- ants. that the ectodomain of E-cadherin is sufficient for bacterial adherence and that the intracytoplasmic domain is required for entry. The critical cytoplasmic region was further mapped to the β-catenin binding domain. Because β-catenin is known to interact with α-catenin. which binds to actin. we generated a fusion moIecule consisting of the ectodomain of E-cadherin and the actin binding site of α-catenin. Cells expressing this chimera were as permissive as E-cadherin-expressing ce1ls. In agreement with these data, α- and β-catenins as well as E-cadherin clustered and colo- calized at the entry site. where F-actin then accumulated. Taken together. these results reveal that E-cadherin, via p- and α-catenins, can trigger dynamic events of actin polymerization and membrane extensions culminating in bacterial uptake.