Figure 3.

The role of scaffolds in cell signaling. (A) In many types of signaling pathways, scaffolds serve to bring together most of the members of the signaling pathway and localize them close to the receptor. This cross-linking property of scaffold molecules ensures that there is an optimal scaffold concentration for the given concentrations of other signaling molecules, potentially allowing for controlling where in the cell the signaling will be most efficient; (B) Preferential localization of scaffolds to particular membrane compartments can ensure that the signaling is relatively high only around those compartments but not elsewhere, the property that might be crucial for cell polarization and directed cell extension or migration. This image shows a signaling scaffold at the leading edge of a migrating cell and the subsequent compartmentalization to the leading edge of its signal (depicted as green gradient).