Fig. 1

Contact tension and cell sorting. a Diagram of two adhering cells and representation of the force equilibrium at a contact vertex. The cadherin adhesive structures are represented in green, and the contractility of the actomyosin cell cortex by red double arrows. Note that cadherin adhesions influence the cell cortex, decreasing tension along contacts (smaller double arrows). The equilibrium of forces at a vertex involves the cortical tension Ct at the free surface of each cell and the contact tension T between the two cells. T is the sum of the two cortical tensions at the contact (Ct′) and of cell–cell adhesion (Adh), which acts in the opposite direction to expand the contact. b Contact tensions in tissues. T _AA and T _BB represent tensions at homotypic contacts. T _AB represents the contact tension at heterotypic contacts, also called here interfacial tension. c Comparison of the four models for cell sorting and separation based on contact tensions. In the differential adhesion hypothesis (DAH) and the differential interfacial tension hypothesis (DITH), the two cell populations have different homotypic tensions, and the heterotypic tension is intermediate. Repulsive mechanisms such as those generated by ephrin-Eph signalling generate high interfacial tension (HIT). The same situation can be achieved in the selective adhesion hypothesis (SAH), due to preferential homotypic cadherin interactions