Prominent 85-kDa oligomannosidic glycoproteins of rat brain are signal regulatory proteins and include the SHP substrate-1 for tyrosine phosphatases.
The glycoprotein component in rat brain reacting most strongly with Galanthus nivalis agglutinin (GNA) on western blots migrates as an 85-kDa band. GNA identifies mannose-rich oligosaccharides because it is highly specific for terminal alpha-mannose residues. After purification of this 85-kDa glycoprotein band by chromatography on GNA-agarose and preparative gel electrophoresis, binding of other lectins demonstrated the presence of fucose and a trace of galactose, but no sialic acid. Treatment with N-Glycanase or endoglycosidase H produced a 65-kDa band, indicating that it consisted of about one-fourth N-linked oligomannosidic carbohydrate moieties. High-performance anion-exchange chromatography and fluorescence-assisted carbohydrate electrophoresis indicated that the major carbohydrate moiety is a heptasaccharide with the structure Manalpha1-6(Manalpha1-3)Manalpha1-6(Manalpha1-3) Manbeta1-4Glc-NAcbeta1-4GlcNAc (Man5GlcNAc2). Determination of amino acid sequences of peptides produced by endoproteinase digestion demonstrated that this 85-kDa mannose-rich glycoprotein component contained the SHP substrate-1 for phosphotyrosine phosphatases and at least one other member of the signal-regulatory protein (SIRP) family. The unusually high content of oligomannosidic carbohydrate moieties on these receptor-like members of the immunoglobulin superfamily in neural tissue could be of functional significance for intercellular adhesion or signaling.
Bartoszewicz
Z P
ZP
Myelin and Brain Development Section, Laboratory of Molecular and Cellular Neurobiology, NINDS, NIH, Bethesda, Maryland, USA.
Jaffe
H
H
Sasaki
M
M
Möller
J R
JR
Stebbins
J W
JW
Gebrekristos
H
H
Quarles
R H
RH
D000595:Amino Acid Sequence; D000818:Animals; D001921:Brain / Q000201:enzymology; D001923:Brain Chemistry / Q000502:physiology*; D027801:Galanthus; D006023:Glycoproteins / Q000235:genetics / Q000378:metabolism*; D006596:Hexosaminidases / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins; D008362:Mannosides / Q000378:metabolism; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000378:metabolism; D010446:Peptide Fragments / Q000378:metabolism; D011485:Protein Binding / Q000502:physiology; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; D017027:Protein Tyrosine Phosphatases / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D054593:SH2 Domain-Containing Protein Tyrosine Phosphatases; D015398:Signal Transduction / Q000502:physiology*; D018909:src Homology Domains / Q000502:physiology
D006023:Glycoproteins; D047908:Intracellular Signaling Peptides and Proteins; D008362:Mannosides; D009844:Oligosaccharides; D010446:Peptide Fragments; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; D017027:Protein Tyrosine Phosphatases; C516727:Ptpn11 protein, rat; C509250:Ptpn6 protein, rat; D054593:SH2 Domain-Containing Protein Tyrosine Phosphatases; D006596:Hexosaminidases