The Biochemistry of O-GlcNAc Transferase: Which Functions Make It Essential in Mammalian Cells?
O-linked N-acetylglucosamine transferase (OGT) is found in all metazoans and plays an important role in development but at the single-cell level is only essential in dividing mammalian cells. Postmitotic mammalian cells and cells of invertebrates such as Caenorhabditis elegans and Drosophila can survive without copies of OGT. Why OGT is required in dividing mammalian cells but not in other cells remains unknown. OGT has multiple biochemical activities. Beyond its well-known role in adding β-O-GlcNAc to serine and threonine residues of nuclear and cytoplasmic proteins, OGT also acts as a protease in the maturation of the cell cycle regulator host cell factor 1 (HCF-1) and serves as an integral member of several protein complexes, many of them linked to gene expression. In this review, we summarize current understanding of the mechanisms underlying OGT's biochemical activities and address whether known functions of OGT could be related to its essential role in dividing mammalian cells.
Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts 02115; email: zebulonlevine@fas.harvard.edu , suzanne_walker@hms.harvard.edu.
Zebulon G
ZG
Levine
Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts 02115; email: zebulonlevine@fas.harvard.edu , suzanne_walker@hms.harvard.edu.
Suzanne
S
Walker
D000215:Acylation; D000818:Animals; D017173:Caenorhabditis elegans / Q000201:enzymology / Q000235:genetics; D002455:Cell Division; D002470:Cell Survival; D004331:Drosophila melanogaster / Q000201:enzymology / Q000235:genetics; D005057:Eukaryotic Cells / Q000166:cytology / Q000201:enzymology*; D006031:Glycosylation; D051863:Host Cell Factor C1 / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D006801:Humans; D008322:Mammals; D051379:Mice; D008958:Models, Molecular; D017351:N-Acetylglucosaminyltransferases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D011499:Protein Processing, Post-Translational; D013045:Species Specificity
C497692:HCFC1 protein, human; D051863:Host Cell Factor C1; D017351:N-Acetylglucosaminyltransferases; C449880:O-GlcNAc transferase
HCF-1; O-GlcNAcylation; O-linked N-acetylglucosamine transferase; OGT structure; TPR; glycosyltransferase mechanism; host cell factor 1; nutrient sensing; tetratricopeptide repeat