[Role of O-GlcNAc modification of cellular proteins in signal transduction]

Glycosylation, consisting in incorporation of single beta-N-acetyl-D-glucosamine residues attached by O-linkage to serine or threonine residues, is a common modification of cytoplasmic and nuclear proteins. Up to now about 200 proteins modified by O-GlcNAc have been identified including transcription factors, signaling components and metabolic enzymes. O-GlcNAc modified proteins can be also phosphorylated. In some cases O-GlcNAc and O-phosphate alternatively occupy the same sites. It has been suggested, that in signal transduction, instead of simple regulation by phosphorylation, more complex mechanism including glycosylation, is involved. Presented work focus on the structure and function of enzymes involved in O-GlcNAc modification and the role of this modification in regulating signal transduction and transcription.