Figure 4.

Sketch of different scenario of PIN-binding. PINs are represented in red and the region with statoliths in gray. (A) Apical/basal/lateral (A/B/L) binding vs. lateral (L) binding. (B) Infinite pool versus limiting pool. In the first case, the surface density of PINs is conserved whereas in the second one, the total number of PINs attached to the cell membrane is conserved. (C) Low sensitivity of PIN to statoliths ($\mathcal{R}\simeq 1$) or high sensitivity ($\mathcal{R}\gg 1$).