Proposed mechanisms for the regulated diffusion of cargo glycoproteins. For either model, we assume that one or more lectins (shown as rods or bullets) with weak affinity for N-glycans transiently bind to N-glycans only when oligomerized. (A) Oligomerization is caused by direct tethering to polymerized actin. (B) A local concentration of the putative lectins occurs by confinement in a microdomain, which is transiently generated by an actin fiber fence, and the clustered lectins trap the glycoproteins. In either case, turnover of actin is greatly reduced under hyperosmolarity, and, thus, glycoproteins become nearly immobilized.