Relationship between Pom1/Tea4 and Tea4 predicted by the simple cluster-based and trans-phosphorylation models. The simple cluster-based model simply reflects the hypothesis that diffusion decreases with Pom1 concentration P. It illustrates that this hypothesis cannot alone explain the decreasing relationship between Pom1/Tea4 and Tea4 (red line). By contrast this relationship is well accounted for qualitatively and quantitatively by the trans-phosphorylation model (blue line; see also 1F). Combining both Pom1 clustering and trans-phosphorylation can also account for the decreasing relationship between Pom1/Tea4 and Tea4 (purple line). 