Figure 1.

Schematic showing protrusion along cell polarization and contact interactions with neighbours. (a) Single cell with polarization $\hat{\mathbf{p}}=\cos \theta {\mathbf{e}}_x+\sin \theta {\mathbf{e}}_y$ and protrusions along $\hat{\mathbf{p}}$ and $-\hat{\mathbf{p}}$. Length of protrusions is l and its angular spread is 2Δθ around θ and θ + π. (b) Cellular protrusions of two cells overlapping each other. Likelihood of contact for two cells is high if their cell polarization vectors are coaxial or the angular range of protrusion is high. (c) The centres of two cells that are within range [(2l − Δl), 2l] of one another but the protrusions do not touch.