Binders of O-glycosylated proteins

Yu, S.H. et al. Proc. Natl. Acad. Sci. USA 109, 4834–4839 (2012).

Many intracellular proteins are modified with O-linked β-N-acetylglucosamine (O-GlcNac). Although it is known that this modification is essential in mammals, there is still much to be learned about the details of its functional roles. To help in this endeavor, Yu et al. describe a method for identifying intracellular binding partners of O-GlcNac–modified proteins. The researchers designed a photo-cross-linking approach in which they engineered cells in culture to incorporate a diazirine-modified form of GlcNac into O-glycosylated proteins; UV-light irradiation of cells then results in specific cross-linking only of O-GlcNac–modified proteins to nearby molecules. After confirming that the approach detects known interactions of O-linked proteins, the researchers used it to identify nuclear transport factors as binding partners of Phe-Gly repeat–containing nucleoporins in mammalian cells.