Fig 2. Conservation of Ser residues in the P-domain of E(spl)-M8.

(A) Alignment of the P-domain of E(spl)-M8 from the indicated Drosophila species, stalk-eyed flies Teleopsis Dalmanii, and mammalian HES6. The evolutionary tree depicts the divergence time of Drosophila species; MYR denotes 10⁶-years. The blue and yellow shaded boxes denote the consensus for MAPK and CK2, respectively (shown at top of alignment). Conserved Ser residues are in bold red. Note that mammalian HES6 harbors six additional residues in the linker separating the MAPK and CK2 sites, and this region harbors the Asp-Asp (DD) motif in the CtD (grey box and black arrow). (B) Transgenic lines for CK2 and MAPK variants were generated using ΦC31 and inserted at site 68E. The nomenclature and predicted behavior of the M8 variants are indicated. Inset on right shows yeast two-hybrid interactions with Groucho; “+” denotes productive interaction.