text: This particular function is considered a scaffold's most basic function.  Scaffolds assemble signaling components of a cascade into complexes.  This assembly may be able to enhance signaling specificity by preventing unnecessary interactions between signaling proteins, and enhance signaling efficiency by increasing the proximity and effective concentration of components in the scaffold complex.  A common example of how scaffolds enhance specificity is a scaffold that binds a protein kinase and its substrate, thereby ensuring specific kinase phosphorylation.  Additionally, some signaling proteins require multiple interactions for activation and scaffold tethering may be able to convert these interactions into one interaction that results in multiple modifications.  Scaffolds may also be catalytic as interaction with signaling proteins may result in allosteric changes of these signaling components. Such changes may be able to enhance or inhibit the activation of these signaling proteins.  An example is the Ste5 scaffold in the mitogen-activated protein kinase (MAPK) pathway.  Ste5 has been proposed to direct mating signaling through the Fus3 MAPK by catalytically unlocking this particular kinase for activation by its MAPKK Ste7.