Murine granulocytic cell adhesion to bone marrow hemonectin is mediated by mannose and galactose.
Hemonectin (HN) is a bone marrow (BM) protein that promotes specific attachment of immature granulocytes and their precursors within the BM. We report that HN is a glycoprotein containing both mannose and galactose residues, and provide evidence that these carbohydrates mediate granulocytic cell adhesion to HN. Carbohydrate structure was determined by digoxigenin-conjugated lectin binding to HN and indicated the presence of mannose, galactose, sialic acid, and the absence of fucose-linked oligosaccharides. The role of carbohydrates in mediating cell adhesion was examined by chemical and enzymatic deglycosylation. Deglycosylation of HN with trifluoromethanesulfonic acid, which cleaves N- and O-linked oligosaccharides, inhibits 66% of cell attachment to HN, and results in an apparent decrease in molecular weight from 60 to 50 kD. Enzymatic deglycosylation with endo-B-N-acetylglucosaminidase H, which hydrolyzes specific N-linked mannose residues, inhibits 30% of cell adhesion to HN. Finally, the role of these specific sugars in hemonectin-mediated cell adhesion was confirmed with neoglycoprotein blocking. Preincubation of BM cells with mannosyl- and galactosyl-BSA probes produces a dose-dependent inhibition of cell attachment to HN, whereas fucosyl-BSA does not inhibit cell adhesion to HN. These results show that mannose and galactose partially mediate adhesion of BM granulocytes to HN.
Sullenbarger
B A
BA
Department of Internal Medicine, University of Michigan, Simpson Memorial Institute, Ann Arbor 48109-0724, USA.
Petitt
M S
MS
Chong
P
P
Long
M W
MW
Wicha
M S
MS
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology / Q000494:pharmacology; D001665:Binding Sites; D001854:Bone Marrow Cells; D002240:Carbohydrate Sequence; D002448:Cell Adhesion; D005690:Galactose / Q000502:physiology*; D006031:Glycosylation / Q000187:drug effects; D006098:Granulocytes / Q000166:cytology* / Q000378:metabolism; D037102:Lectins / Q000378:metabolism; D008358:Mannose / Q000502:physiology*; D017038:Mannosyl-Glycoprotein Endo-beta-N-Acetylglucosaminidase / Q000494:pharmacology; D008565:Membrane Proteins / Q000737:chemistry / Q000276:immunology / Q000378:metabolism*; D008698:Mesylates / Q000494:pharmacology; D051379:Mice; D008969:Molecular Sequence Data
D000911:Antibodies, Monoclonal; D037102:Lectins; D008565:Membrane Proteins; D008698:Mesylates; C053949:haemonectin; D017038:Mannosyl-Glycoprotein Endo-beta-N-Acetylglucosaminidase; C012077:trifluoromethanesulfonic acid; D008358:Mannose; D005690:Galactose