A) During the formation of cell-cell contact, the membranes of adjacent cells protrude toward one another. Nectins on one cell bind nectins on neighboring cells and recruit afadin which in turn binds ZO-1. The nectins form a transient adhesion that brings two opposing membranes into close proximity. (B) The extracellular domains of cadherins dimerize with cadherins on adjacent cells and the cytoplasmic domain recruits β-catenin recruits α-catenin, an afadin binding protein. C) As the adherens junctions continue to mature, ZO-1 interacts transiently with α-catenin. D) The tight junctions begin to form, ZO-1 binds occludin, and then tight junctions migrate more apically. The brown lines indicate the plasma membranes of two adjacent.