Dephosphorylated mutations affect the protein-protein interactions of ERF in Populus simonii x P.nigra

Phosphorylation is a common type of post-translational modification(PTM).It plays a vital role in many cellular processes.The reversible phosphorylation and dephosphorylation affect protein structures and protein-protein interactions.Previously,we obtained five proteins that interact with ethylene-responsive factor(ERF)from the cDNA library of Populus simonii x Populus nigra.To further investigate the effect of dephosphorylation of PsnERF on its protein binding ability,we generated different phosphorylation states of PsnERF and demonstrated their protein binding capacity by the yeast two-hybrid assay(Y2H).The secondary structures and 3D structures of PsnERF,ERFm,TrunERF,and psnerf^(197/198/202a) were predicted by homology modeling.The Y2H assay indicated that the deletion of serine-rich regions does not affect the interactions,while dephosphorylated mutations blocked the interactions.Homology modeling results suggested that the protein-binding activity was affected by dephosphorylation,and the S197/S198/S202 residues of PsnERF may be the key phosphorylation sites influencing its binding ability.