Identification of lectin-like substances recognizing galactosyl residues of glycoconjugates on the plasma membrane of marrow sinus endothelium
Plasma membrane components capable of specific binding to the sugar residues of glycoproteins have recently been identified in several cell systems and implicated in the recognition and specific uptake of soluble or membrane-bound glycoproteins. Because the endothelium of bone marrow sinuses is the site of massive cellular and molecular traffic that is often specific, we studied the surface of sinus endothelium for the presence of sugar-recognizing systems. Neoglycoprotein probes were synthesized by covalently binding bovine serum albumin (BSA) to activated pyrannose form of galactose, fucose, or mannose. The probe was then labeled with colloidal gold. Galactosyl-BSA gold bound to endothelial membrane at 4 degrees C and was internalized at 37 degrees C. Both the binding and the internalization were inhibited in the presence of excess unlabeled galactosyl-BSA. Gold-labeled mannosyl-BSA and fucosyl-BSA did not bind to the endothelium. Nor did BSA-gold without galactosyl residues bind to endothelial membrane, confirming that galactosyl moiety was responsible for the binding. The uptake of galactosyl-BSA was further confirmed by perfusion of /sup 125/I-galactosyl-BSA into the abdominal aorta. Small but highly specific uptake was noted in tibias and femurs. These data provide evidence for the presence of a lectin-like substance on the luminal surface of marrow endothelial membrane capable of specific interaction with galactosyl residues of circulating and cell-bound glycoproteins and may provide a mechanism for specific recognition of these glycoproteins.
- OSTI ID:
- 5097368
- Journal Information:
- Blood; (United States), Vol. 5
- Country of Publication:
- United States
- Language:
- English
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BONE MARROW
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MEMBRANE TRANSPORT
LECTINS
BIOLOGICAL FUNCTIONS
ALBUMINS
CELL MEMBRANES
FEMUR
GOLD
IODINE 125
RATS
TIBIA
TRACER TECHNIQUES
ANIMAL TISSUES
ANIMALS
BETA DECAY RADIOISOTOPES
BODY
CARBOHYDRATES
CELL CONSTITUENTS
DAYS LIVING RADIOISOTOPES
ELECTRON CAPTURE RADIOISOTOPES
ELEMENTS
FUNCTIONS
HEMATOPOIETIC SYSTEM
INTERMEDIATE MASS NUCLEI
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ISOTOPE APPLICATIONS
ISOTOPES
MAMMALS
MEMBRANES
METALS
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANS
PROTEINS
RADIOISOTOPES
RODENTS
SACCHARIDES
SKELETON
TISSUES
TRANSITION ELEMENTS
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550501* - Metabolism- Tracer Techniques
550201 - Biochemistry- Tracer Techniques