Identification of O-linked N-acetylglucosamine modification of ankyrinG isoforms targeted to nodes of Ranvier

J Biol Chem. 1996 Dec 6;271(49):31391-8. doi: 10.1074/jbc.271.49.31391.

Abstract

AnkyrinGs of 270 and 480 kDa are localized at nodes of Ranvier and are candidates to couple the voltage-dependent sodium channel and neurofascin to the spectrin/actin network. This study presents evidence that these ankyrins contain O-linked GlcNAc residues and identifies as the site of glycosylation a serine-rich domain that distinguishes them from other ankyrin isoforms. The 480-kDa ankyrinG, extracted from brain membranes associated with wheat germ agglutinin-affinity columns, was [3H]galactose-labeled with UDP-[3H] galactose and galactosyltransferase, and cross-reacted with an antibody against O-GlcNAc monosaccharides. AnkyrinG-associated sugars are O-linked monosaccharides based on resistance to peptide-N-glycosidase F and analysis of saccharides released by beta-elimination. The serine-rich domain is the site of glycosylation based on wheat germ agglutinin binding activity of polypeptides produced by in vitro translation in reticulocyte lysates. Immunofluorescence revealed co-localization of ankyrinG and O-GlcNAc immunoreactivity at nodes of Ranvier. These observations suggest that ankyrin at the node of Ranvier is O-GlcNAc-glycosylated and are the first demonstration of a post-translational modification that is concentrated at the node of Ranvier and not in adjacent areas of myelinated axons.

MeSH terms

  • Acetylglucosamine*
  • Ankyrins / chemistry
  • Ankyrins / metabolism*
  • Brain Chemistry
  • Galactose / metabolism
  • Galactosyltransferases / metabolism
  • Glycosylation
  • Humans
  • Molecular Weight
  • Ranvier's Nodes / chemistry*
  • Tissue Distribution
  • Wheat Germ Agglutinins / metabolism

Substances

  • Ankyrins
  • Wheat Germ Agglutinins
  • Galactosyltransferases
  • Acetylglucosamine
  • Galactose