Functional Analysis of the Glucuronyltransferases GlcAT-P and GlcAT-S of Drosophila melanogaster: Distinct Activities towards the O-linked T-antigen

• Main Authors: Isabelle Breloy, Tilo Schwientek, Deborah Althoff, Marvin Holz, Tim Koppen, Angelika Krupa, Franz-Georg Hanisch
• Format: Article
• Language: English
• Published: MDPI AG 2016-01-01
• Series: Biomolecules
• Subjects: glucuronyltransferases; Drosophila melanogaster; N-glycans; O-glycans; mass spectrometry; glycomics
• Online Access: http://www.mdpi.com/2218-273X/6/1/8

The Drosophila melanogaster glucuronyltransferases dGlcAT-S and dGlcAT-P were reported to be expressed ubiquitously and results of in vitro activity assays indicate a functional redundancy. We analyzed both transferases in vivo and in vitro and could show significant differences in their activity towards N-and O-glycoproteins in vivo. While GlcAT-P is able to use N-linked N-acetyllactosamine chains and the O-linked T-antigen as a substrate to form non-sulfated HNK1- (GlcAβ1-3Galβ1-4GlcNAcβ1-) and glucuronyl-T-antigens in vivo, GlcAT-S adds glucuronic acid only to N-linked chains, thereby synthesizing only the non-sulfated HNK1-antigen.