Sandbox Reserved 381: Difference between revisions

From Proteopedia
Jump to navigationJump to search
Line 15: Line 15:
O-GlcNAc modification has been described for a large and still increasing number of proteins, many of which are key modulators of cellular signalling.  O-GlcNAc modifications are catalysed by a glycosyltransferase named O-linked N-acetylglucosaminyltranserase (OGT), and are removed by the antagonistic enzyme B-N-acetylglucosaminidase (O-GlcNAcase). The general scheme of O-linked N-acetylglucosamine modification suggests that N-acetylglucosamine is added to serine/threonine (Ser/Thr) residues of target proteins by the enzyme OGT using UDP-GlcNac as substrate.  The N-acetylglucosamine group is removed by the antagonistic activity of O-GlcNAcase. <ref>Alexander G, Danilo G. The O-linked N-acetylglucosamine modification in cellular signalling and the immune system. EMBO reports. 2008 June;9:748-753[http://www.nature.com/embor/journal/v9/n8/full/embor2008129.html]</ref>
O-GlcNAc modification has been described for a large and still increasing number of proteins, many of which are key modulators of cellular signalling.  O-GlcNAc modifications are catalysed by a glycosyltransferase named O-linked N-acetylglucosaminyltranserase (OGT), and are removed by the antagonistic enzyme B-N-acetylglucosaminidase (O-GlcNAcase). The general scheme of O-linked N-acetylglucosamine modification suggests that N-acetylglucosamine is added to serine/threonine (Ser/Thr) residues of target proteins by the enzyme OGT using UDP-GlcNac as substrate.  The N-acetylglucosamine group is removed by the antagonistic activity of O-GlcNAcase. <ref>Alexander G, Danilo G. The O-linked N-acetylglucosamine modification in cellular signalling and the immune system. EMBO reports. 2008 June;9:748-753[http://www.nature.com/embor/journal/v9/n8/full/embor2008129.html]</ref>


== Gangliosides ==
== N Terminus ==


Gangliosides are in the category of glycosphingolipids and are found predominately in neuronal tissues. Gangliosides consist of sialic acid linked to a sugar (glucose, galactose, GalNAc, GlcNAc and/or fructose) backbone attached to a ceramide base. These gangliosides make up approximately 10% of a neuron’s total lipid content and like other lipids, gangliosides function in cell signal transduction.<ref>PMID: 16158191 </ref>
The N terminus of OGT is unusual, consisting of 2.5-13.5 tetratricopeptide repeats (TPRs) dpending on alternative splicing.<ref>Kreppel L, Hart G. Regulation of a cytosolic and nuclear O-GlcNAc transferase. Role of the tetratricopeptide repeats. J Biol Chem. 1999;274:32015-32022</ref>


== Tetanospasmin (TeNT) ==
== Tetanospasmin (TeNT) ==