Fig. 3. The crosstalk between protein phosphorylation and O-GlcNAcylation.

a Protein substrate can be either O-GlcNAcylated or phosphorylated at the same amino acid residue in a substitutable and competitive way. b Protein substrate is either phosphorylated at given sites or O-GlcNAcylated at other different sites, which is both reciprocal and alternative. c Protein substrate is simultaneously under O-GlcNAcylation and phosphorylation at different locations.