Cytoplasmic O-GlcNAc modification of the head domain and the KSP repeat motif of the neurofilament protein neurofilament-H

J Biol Chem. 1996 Aug 23;271(34):20845-52. doi: 10.1074/jbc.271.34.20845.

Abstract

Neurofilaments, the major intermediate filaments in large myelinated neurons, are essential for specifying proper axonal caliber. Mammalian neurofilaments are obligate heteropolymers assembled from three polypeptides, neurofilament (NF)-H, NF-M, and NF-L, each of which undergoes phosphorylation at multiple sites. NF-M and NF-L are known to be modified by O-linked N-acetylglucosamine (O-GlcNAc) (Dong, D. L.-Y., Xu, Z.-S., Chevrier, M. R., Cotter, R. J., Cleveland, D. W., and Hart, G. W. (1993) J. Biol. Chem. 268, 16679-16687). Here we further report that NF-H is extensively modified by O-GlcNAc at Thr53, Ser54, and Ser56 in the head domain and, somewhat surprisingly, at multiple sites within the Lys-Ser-Pro repeat motif in the tail domain, a region in assembled neurofilaments known to be nearly stoichiometrically phosphorylated on each of the approximately 50 KSP repeats. Beyond the earlier identified sites on NF-M and NF-L, O-GlcNAc sites on Thr19 and Ser34 of NF-M and Ser34 and Ser48 of NF-L are also determined here, all of which are localized in head domain sequences critical for filament assembly. The proximity of O-GlcNAc and phosphorylation sites in both head and tail domains of each subunit indicates that these modifications may influence one another and play a role in filament assembly and network formation.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Acetylglucosamine / metabolism*
  • Amino Acid Sequence
  • Animals
  • Glycopeptides / chemistry
  • Glycosylation
  • Male
  • Molecular Sequence Data
  • Nerve Tissue Proteins / chemistry
  • Neurofilament Proteins / chemistry
  • Neurofilament Proteins / metabolism*
  • Peptide Mapping
  • Protein Processing, Post-Translational
  • Rats
  • Repetitive Sequences, Nucleic Acid
  • Serine / chemistry
  • Spinal Cord / chemistry

Substances

  • Glycopeptides
  • Nerve Tissue Proteins
  • Neurofilament Proteins
  • Serine
  • Acetylglucosamine