More frequently scaffs provide a scaffold

Think about entities that provide flexible –often modular and temporary- solutions. In the macroscopic world one may envision bamboo or scaffold towers. There is an interesting group of proteins in cells that support the same functionality, the scaffolding proteins.
Scaffs contain protein motifs (eg. SH2,SH3, PDZ domains) that support specific interactions between proteins as well as Internally Disorganized Regions (IDRs), flexible protein regions with a role in multiprotein complex interactivity.
If scaffs link 2 proteins, they are known as 'linkers' or 'adaptors'.
More frequently scaffs provide a scaffold for more than 2 proteins. One of the emerging structural designs with a specific functional role is the support of a 3-tier kinase signaling module.
Important regulatory functions include:
1.Degradation: eg. axin binds phosphorylated β-catenin and facilitates phosphorylation by GSK-3β in the absence of Wnt signaling activity; As such it promotes degradation. Upon activation by Wnt-frizzled unphosphorylated catenin may build up in the cytosol and trigger downstream processes in the nucleus (link)
2.Localization: eg. One has found that Arf-proteins are expressed and targeted in a cell- and membrane-specific pattern in kidney epithelial cells gyq6dnu.
3.Clustering: eg. PSD-95 support multimerization of voltage-activated potassium channels; likewise ankyrins have been shown to play an important role in transport of ion channels in cardiac cells. 4.Complex signaling: GTPase proteins from the GIMAP family, in lymphocytes were demonstrated (Schwefel and Daumke, Small Gtpases. 2011) to link together ("oligomerize") and interact with lipid droplets; This may allow for a metastable platform for specialized signaling like interaction with apoptotic bcl proteins. This kind of dynamic membrane scaffolding is part of current research. Also, in the next section, Ste5 is an example of a MAPK kinase scaffold that determines the switch-like mating response in yeast...

One of the "must know scaffs" is a scaffold protein that determines the mating response in yeast. It has been named "STE5". STE refers to 'sterile' proteins, in which mutations cause deficit signaling of the mating pheromone (Bardwell, Peptides 2004).
Ste5 is crucial in the mating response as it tethers multiple kinases and acts as an allosteric kinase activator (PM ID:8062390). The short-cut explanation is that the phosphorylation state of one of the interaction partners, Fus3, acts as a switch that determines the fast "2-minutes" mating response. Once the phosphorylation of Fus3 is complete, it dissociates from ste5 and phosphorylates downstream targets to start the mating response, called 'shmooing'.
http://www.shscaffolding.com/