FIG 6 .

Features of PPZ1 that limit its interaction with GLC7 regulators. (A) Cartoon illustrating that the presence of the disordered N-terminal domain, the lack of conservation of key PP1/GLC7 interaction domains (such as the ΦΦ binding pocket), and the presence of the PPZ1-specific helix negatively impact the binding of PPZ1 with many GLC7-specific regulators, leaving the regulators to preferentially bind and regulate the activity of GLC7. (B) Overlay of PPZ1 (pink) and PP5 (blue; PDB no. 1S95 [30]), illustrating that the C-terminal helices of the two proteins bind different pockets in the core PSP catalytic domain.