Force-extension relationship of cell-cell contacts.

Adherens junctions (AJ) are adhesive motifs joining neighboring cells. The physical contacts are fingerlike structures which grow perpendicular to the cell-cell interface. While their length may vary with the applied force, their density is independent of length. Here we measure AJ contact lengths while varying the mean contractile force of the cell using nocodazole. Using this assay and a simple mechanical model, we measure an effective spring constant of about 30 pN/microm per finger. This measurement may enable the estimation of cell monolayer force distributions from a simple AJ image.