Schematic depiction of cis- and trans-interactions between E-cadherin ectodomains (ECs) on the cell surface.

Trans-interactions (highlighted in red) are mediated by the EC1 and occur between cadherin molecules of neighboring cells. Lateral cis-interactions (indicated in yellow) occur between the EC1 of one cadherin molecule and the EC2, the EC2/EC3 linker region and part of the EC3 of an adjacent cadherin molecule exposed on the same cell. A combination of cis- and trans-interactions is depicted on the right hand side of the scheme. Here, the EC1 is simultaneously engaged in a cis-interaction with an adjacent cadherin molecule from the same cell, as well as in a trans-interaction with a cadherin molecule from an opposite cell (the EC2 involved in both cis- and trans- interactions is colored in yellow and red). Model based on [14], [57], [58].