Dear Editor,rnO-GIcNAcylation is a nutrient sensor that is particularly sensitive to environmental glucose(Hardiville and Hart,2014).Glucose can be converted to UDP-GIcNAc through the hexosamine biosynthetic pathway,providing a substrate for O-GIcNAcylation.Two enzymes participate in this rever-sible modification,O-GIcNAc transferase(OGT),which adds a single GIcNAc residue to the serine/threonine sites of proteins,and O-GIcNAcase(OGA),which removes the residue(Yang and Qian,2017).OGT is a highly conserved,single gene-encoded protein that is ubiquitously expressed in higher eukaryotes,and human OGT shares more than 65％ sequence identity with its Caenorhabditis elegans and Drosophila melanogaster orthologs(Jinek et al.,2004).O-GIcNAcylation can influence protein conformation,activity,interaction,half-life,and subcellular localization.