OGT

OGT encodes an O-linked N-acetylglucosamine (GlcNAc) transferase, which transfers GlcNAc directly to Ser or Thr of proteins using UDP-GlcNAc as a donor substrate. GlcNAc modification by OGT is performed in the nucleus and cytoplasm, unlike the general glycosylation performed in the Golgi apparatus. Therefore, the substrates of OGT are nuclear and cytoplasmic proteins, and this reaction competes with phosphorylation. O-GlcNAc modification is a reversible reaction, and the added GlcNAc is removed by O-GlcNAc hydrolase (OGA). O-GlcNAc modification is involved in various cellular functions such as transcription and signal transduction, including the regulation of phosphorylation.