Binding of partially reassembled high-density lipoprotein to isolated human small intestine epithelial cells. Effect of lipid composition.
The binding of human high-density lipoprotein (HDL3), apolipoprotein A-I (apoA-I) and recombinants of apoA-I with cholesterol and/or dimyristoylphosphatidylcholine (DMPC) to the HDL receptor on isolated human small intestine epithelial cells was studied. ApoA-I competed for 125I-labelled HDL3 binding sites less effectively than HDL3, and a lower amount of 125I-labelled apoA-I than 125I-HDL3 was bound to cells. The apoA-I/DMPC recombinant competed for 125I-HDL3 binding sites nearly as well as HDL3, and 125I-apoA-I/DMPC recombinant bound to cells with at least the same efficiency as 125I-HDL3. The apoA-I/DMPC/cholesterol recombinant failed to compete for 125I-HDL3 binding sites, and the 125I-apoA-I/DMPC/cholesterol complex binding to cells was several-fold lower than that of other particles. All particles bound to cells with similar dissociation constants. Tetranitromethane-modified HDL3 failed to bind to high-affinity specific binding sites and compete with 125I-HDL3 for binding. The results obtained make it possible to assume that, while apoA-I may be a determinant of the HDL receptor, the lipid composition of the lipoprotein may affect its interaction with the receptor.
Sviridov
D D
DD
Institute of Experimental Cardiology, USSR Cardiology Research Center, Moscow.
Misharin
A Y
AY
Safonova
I G
IG
Bushmakina
N G
NG
Repin
V S
VS
Smirnov
V N
VN
D016632:Apolipoprotein A-I; D001054:Apolipoproteins A / Q000378:metabolism; D002352:Carrier Proteins; D004848:Epithelium / Q000378:metabolism; D006801:Humans; D007421:Intestine, Small / Q000166:cytology / Q000378:metabolism*; D007700:Kinetics; D008055:Lipids / Q000032:analysis*; D008075:Lipoproteins, HDL / Q000378:metabolism*; D053440:Lipoproteins, HDL3; D016601:RNA-Binding Proteins; D011956:Receptors, Cell Surface / Q000378:metabolism; D018110:Receptors, Lipoprotein
D016632:Apolipoprotein A-I; D001054:Apolipoproteins A; D002352:Carrier Proteins; D008055:Lipids; D008075:Lipoproteins, HDL; D053440:Lipoproteins, HDL3; D016601:RNA-Binding Proteins; D011956:Receptors, Cell Surface; D018110:Receptors, Lipoprotein; C031616:high density lipoprotein receptors; C075197:high density lipoprotein binding protein