' O -GlcNAc Code' Mediated Biological Functions of Downstream Proteins

As one of the post-translational modifications, -linked β- -acetylglucosamine ( -GlcNAc) modification ( -GlcNAcylation) often occurs on serine (Ser) and threonine (Thr) residues of specific substrate cellular proteins via the addition of -GlcNAc group by -GlcNAc transferase (OGT). Maintenance of normal intracellular levels of -GlcNAcylation is controlled by OGT and glycoside hydrolase -GlcNAcase (OGA). Unbalanced -GlcNAcylation levels have been involved in many diseases, including diabetes, cancer, and neurodegenerative disease. Recent research data reveal that -GlcNAcylation at histones or non-histone proteins may provide recognition platforms for subsequent protein recruitment and further initiate intracellular biological processes. Here, we review the current understanding of the ' -GlcNAc code' mediated intracellular biological functions of downstream proteins.