Regulation of E2F-1 by methylation and NEDDylation

E2F-1 has a central role in cell cycle orchestration, and its activity is tightly regulated. One of the ways E2F-1 activity is controlled is by direct modification by post translational modifications such as acetylation, ubiquitination and phosphorylation. Here it was demonstrated that E2F-1 is targeted by two novel modifications, namely methylation by Set7/9 and NEDDylation, both within the DNA binding and heterodimerisation domain of the protein. NEDDylation and methylation of E2F-1 both decrease the stability and diminish the transcriptional activity of E2F-1. Lysine residues in E2F-1 involved in NEDDylation are also targeted by methylation, allowing the potential for interplay between these modifications. Methylation of E2F-1 was demonstrated to be a prerequisite for its NEDDylation and the multi-domain protein UHRF1 implicated in mediating this effect. The results define a new level of control on E2F-1 and suggest a protein code with pleiotropic effects involved in E2F-1 regulation.