The early metazoan Trichoplax adhaerens possesses a functional O-GlcNAc system

Protein O-GlcNAcylation is a reversible post-translational signalling modification of nucleocytoplasmic proteins that is essential for embryonic development in bilateria. In a search for a reductionist model to study O-GlcNAc signaling, we discovered the presence of functional O-GlcNAc transferase (OGT), O-GlcNAcase (OGA) and nucleocytoplasmic protein O-GlcNAcylation in the most basal extant animal, the placozoan Trichoplax adhaerens. We show via enzymatic characterization of Trichoplax OGT/OGA and genetic rescue experiments in Drosophila melanogaster that these proteins possess activities/functions similar to their bilaterian counterparts. The acquisition of O-GlcNAc signalling by metazoa may have facilitated the rapid and complex signalling mechanisms required for the evolution of multicellular organisms.