O-linked beta-N-acetylglucosamine (O-GlcNAc) is a sugar attachment to serine or threonine hydroxyl moieties on nuclear and cytoplasmic proteins. O-GlcNAc modified proteins are generally either cytoplasmic or nuclear proteins, and unlike asparagine-linked or mucin-type O-glycosylation, O-GlcNAc is not further processed into a complex oligosaccharide. In many ways, O-GlcNAc is similar to protein phosphorylation; for example the sugar can be attached or removed dynamically in response to changes in the cellular environment triggered by stress, hormones, or nutrients (1).
-Western-Blot-NB300-614-img0002.jpg "WB analysis of O-GlcNAc in in 1) HeLa, 2) NTERA-2, 3) PC-12 and 4) COS-7 cell lysates")
Recently, it was reported that glucose deprivation increases protein O-GlcNAcylation in cancerous cells (2). Thus, protein O-GlcNAcylation in tumors may have a function in overcoming the effects of hypoxia and hypoglycemia. These findings suggest that glycogen is the source for increased O-GlcNAcylation but not for generating ATP in response to glucose deprivation and this may be useful for cancer cells to survive (3). Immunoblotting analysis using the O-GlcNAc-specific antibodies has indicated that glucose deprivation increases protein O-GlcNAcylation in some cancer cells. O-GlcNAcylation of proteins for effective use of sugar under stress and deprivation conditions is one of the adaptive responses of the cancerous cells and further research is needed to clarify the physiological and pathological role of these novel pathways.
Novus Biologicals offers O-GlcNAc reagents for your research needs including:
