Figure 3.

Xenopus cephalic NC cells are polarized by contact-inhibition of locomotion. (A) Contact-Inhibition of Locomotion is triggered by cell interactions. Cells are polarized according to their cell-cell contacts; free edge is in green, cell contacts are in red. (B) Cell-cell interactions are mediated by N-Cadherin and Wnt/PCP signaling. N-Cadherin is required for a local inhibition of Rac1 at the cell junctions and Wnt/PCP induces an increase of RhoA activity at the contact. Both N-Cadherin and Wnt/PCP maintain low Rac1 and high RhoA activities at the cell-cell contact which restrict Rac1 activity at the free edge.