Fig. 8. The sequence of the constitutively active KSR3 can be used to predict mutations that over-activate human B-RAF.

a Effects of individual mutations of B-RAF on its ability to activate ERK signalling. The graph represents the relative ERK activation caused by the mutants compared to WT human B-RAF. Data represent the mean +/− s.e.m. of three independent transfections. b Like the V600E, the strongest novel gain-of-function mutants of B-RAF such as L485R and R506E are only partially affected by the presence of the R509H mutation. The two blots are from different experiments but contain the appropriate controls. c Like the S361E mutation of KSR3, the R506E activating mutation of hB-RAF rescues the ability to activate ERK signalling to a mutant form of hB-RAF in which the SSDD motif of the NtA has been replaced by AAAA. The graph represents the relative ERK activity of the mutants compared to WT human B-RAF. Data represent the mean +/− s.e.m. of three independent transfections. d Correspondence between the residues mutated in the sea urchin KSR3 protein and the homologous residues in human B-RAF. Source data are provided as a Source Data file. Information about quantification and replication of the western blots are provided in Supplementary Table 1.