(A) Bootstrapped phylogenetic tree of Ste18 orthologs from the Ascomycota phylum showing the evolutionary co-occurrence of regulatory phosphorylation sites on the N-terminal tail of the Gγ subunit and the FBD of orthologous Ste5 scaffolds. The presence of Ste5 orthologous proteins, functional Ste5-like FBDs, and N-terminal Gγ phospho-regulatory intrinsically disordered regions (IDRs) are shown next to yeast species harboring each element.
(B) Species that contain the synergistic regulatory element (Ste18Nt and Ste5FBD) are nearly 100% identical at phosphorylation site alignment positions in Ste18 and MAPK binding sites reported previously in Ste5 (Coyle et al., 2013).
See also Figure S7.