PMID: 8344946

 

    Legend: Gene, Sites

Title : Glycosylation of mammalian neurofilaments

Abstract :

1. Localization of multiple O-linked N-acetylglucosamine moieties on neurofilament polypeptides L and M. Neurofilaments are neuronal intermediate filaments that play an important role in the growth and maintenance of large myelinated axons
2. Mammalian neurofilaments are composed of three polypeptide subunits , designed as NF-L , NF-M , and NF-H , all of which are phosphorylated
3. Here, we demonstrate by several criteria that neurofilament polypeptides are also modified by an abundant type of intracellular protein glycosylation in which single N-acetylglucosamine monosaccharides are O-glycosidically (O-GlcNAc) linked to serine or threonine residues
4. In purified neurofilament proteins , the O-GlcNAc modifications occur at a stoichiometry of approximately 0.1 and 0.15 mol of GlcNAc/mol of NF-L and NF-M , respectively
5. The predominant sites of O-GlcNAc attachment on NF-L and NF-M are identified using proteolysis, purification of the glycopeptides , and subsequent analysis by automated gas-phase sequencing, manual Edman degradation, and laser desorption mass spectrometry
6. For NF-L , both major sites of glycosylation ( Thr21 and Ser27 ) are located at the NH2-terminal head domain
7. For NF-M , one major site ( Thr48 ) lies within the NH2-terminal head domain , whereas the other ( Thr431 ) is located at the tail domain
8. Deletions encompassing these sites have been shown previously to have a dominant detrimental effect upon neurofilament assembly, raising questions about the specific function(s) of the saccharide moieties at these sites
9. Specific identification of these O-GlcNAc attachment sites has set the stage for more detailed mutagenic analysis of O-GlcNAc functions on neurofilaments

Output (sent_index, trigger, protein, sugar, site):

• 1. moieties, , -, neurofilament polypeptides L and M. Neurofilaments, polypeptides
• 3. linked, , -, single N-acetylglucosamine monosaccharides, serine
• 3. linked, , -, single N-acetylglucosamine monosaccharides, threonine residues
• 3. serine, , -, -, threonine residues
• 4. NF-L, , NF-L, GlcNAc/mol, -
• 4. NF-M, , NF-M, GlcNAc/mol, -
• 5. glycopeptides, , -, -, glycopeptides
• 6. glycosylation, , -, -, Thr21 and Ser27
• 6. glycosylation, , -, -, sites

Output(Part-Of) (sent_index, protein, site):

• 5. NF-L, sites
• 5. NF-M, sites

*Output_Site_Fusion* (sent_index, protein, sugar, site):

• 6. -, -, Thr21 and Ser27

 

Protein	NCBI ID	SENTENCE INDEX
NF-M	4741	2,4,5,7
NF-L	4747	2,4,5,6
NF-H	4744	2