Dynamic Isotopic Detection of Aminosugars With Glutamine (IDAWG) for Released Glycans and O-GlcNAc Modified Proteins

The Isotopic Detection of Aminosugars With Glutamine (IDAWG) method was originally developed for the glycomics field as a quantitative tool that takes advantage of the hexosamine biosynthetic pathway, isotopically labeling nitrogen-containing glycans in cell culture systems via the use of ¹⁵N-Gln^1,2. Here, we present an adaptation of this method, Dynamic IDAWG, that allows for the calculation of half-lives and sialic acid remodeling for released glycans in a given sample following analyses by mass spectrometry. An additional benefit of this method is that cycling rates of the post-translational modification O-linked β-N-acetylglucosamine (O-GlcNAc) can also be determined. O-GlcNAc is found on thousands of nuclear and cytosolic proteins in mammals and is thought to be a regulatory modification, playing a role in a variety of cellular processes³. The modification cycles on and off serine and threonine residues by means of O-GlcNAc Transferase (OGT) and O-GlcNAc Hydrolase (OGA)⁴. O-GlcNAc is thought to be a dynamic modification; that is, the modification exhibits a shorter half-life than the modified protein⁵.  However, dynamics have only been evaluated on a small number of O-GlcNAc modified proteins due to the laborious and insensitive methods that are available. Therefore, there is an urgent need in the field to develop high-throughput, sensitive methods to evaluate the dynamics of O-GlcNAc on a global scale. Here, we illustrate the utility of Dynamic IDAWG in cell culture systems to evaluate the turnover of complex N- and O-linked glycans as well as delineating the half-life of O-GlcNAc on nuclear and cytosolic proteins. 

References:

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