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. Author manuscript; available in PMC: 2011 Jun 17.
Published in final edited form as: Science. 2011 May 6;332(6030):680–686. doi: 10.1126/science.1198701

Fig. 4. Allosteric regulation by scaffold proteins.

Fig. 4

A) Scaffolds can allosterically modulate the conformation of enzymes and substrates to gate information flow. B) In MAPK ERK signaling, KSR can directly bind to the MAPKKK Raf and influence its activity toward the MAPKK MEK. The pseudokinase domain of KSR dimerizes with Raf, altering the conformation of the C-helix on Raf so that its kinase domain becomes catalytically active (thereby allowing Raf to phosphorylate MEK). C) The VWA domain of Ste5 promotes phosphorylation of the MAPK Fus3 by the MAPKK Ste7. The scaffold may unlock the activation loop of the MAPK Fus3 to make it a better substrate for MAPKK Ste7.