Characterization of a receptor for oxidized low-density lipoproteins on rat Kupffer cells: similarity to macrosialin.
Rat liver Kupffer cell membranes contain a protein that recognizes specifically oxidized low-density lipoproteins (oxLDL). Visualization after blotting under reducing conditions indicates that the receptor is a monomeric protein, with an estimated molecular mass of 115-120 kDa. N-Glycosidase F and endoglycosidase F treatment resulted in a fall in estimated molecular mass of 24 and 11 kDa respectively, whereas O-glycosidase was ineffective. No effect on the extent of interaction with oxLDL was noticed, suggesting that glycans are not essential for ligand recognition. Using a polyclonal antibody to mouse macrosialin, we visualized macrosialin on blot, and compared this glycoprotein with the oxLDL-binding protein. It appears that the two glycoproteins have a similar molecular mass and are comparably affected by treatment with the different glycosidases. Incubation with trypsin resulted in a reduction in the estimated molecular mass of about 25 kDa for both the oxLDL-binding protein and macrosialin. These results indicate that the oxLDL-binding protein and macrosialin are identical, suggesting a role for macrosialin in modified LDL catabolism.
Van Velzen
A G
AG
Division of Biopharmaceutics, Leiden-Amsterdam Center for Drug Research, Sylvius Laboratories, The Netherlands.
Da Silva
R P
RP
Gordon
S
S
Van Berkel
T J
TJ
D000818:Animals; D015703:Antigens, CD; D015214:Antigens, Differentiation, Myelomonocytic; D003429:Cross Reactions; D006026:Glycoside Hydrolases / Q000494:pharmacology; D006801:Humans; D015151:Immunoblotting; D007728:Kupffer Cells / Q000737:chemistry* / Q000166:cytology; D008099:Liver / Q000737:chemistry* / Q000166:cytology; D008297:Male; D008562:Membrane Glycoproteins / Q000187:drug effects / Q000276:immunology / Q000302:isolation & purification*; D051379:Mice; D010084:Oxidation-Reduction; D051381:Rats; D017208:Rats, Wistar; D011973:Receptors, LDL / Q000187:drug effects / Q000276:immunology / Q000302:isolation & purification*; D051131:Receptors, Oxidized LDL; D051127:Scavenger Receptors, Class E; D014357:Trypsin / Q000494:pharmacology; D000097382:CD68 Molecule
D015703:Antigens, CD; D015214:Antigens, Differentiation, Myelomonocytic; D006026:Glycoside Hydrolases; D008562:Membrane Glycoproteins; D011973:Receptors, LDL; D051131:Receptors, Oxidized LDL; D051127:Scavenger Receptors, Class E; D014357:Trypsin; C081026:CD68 protein, mouse; D000097382:CD68 Molecule; C495137:OLR1 protein, human; C495136:OLR1 protein, rat; C495138:Olr1 protein, mouse