Presence of CLA-1 and HDL binding sites on syncytiotrophoblast brush border and basal plasma membranes of human placenta
| Autor: | Marie-Claude Charest, J. Lafond, J.-F Alain, Louise Brissette, André Masse, Jacques Robidoux, Lucie Simoneau |
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| Rok vydání: | 1999 |
| Předmět: |
CD36 Antigens
medicine.medical_specialty Brush border Lipoproteins Placenta Biology Binding Competitive Iodine Radioisotopes chemistry.chemical_compound Syncytiotrophoblast Fetal membrane Pregnancy Internal medicine medicine Humans Binding site Receptors Immunologic Receptors Lipoprotein Receptors Scavenger Binding Sites Microvilli Cholesterol Cell Membrane Obstetrics and Gynecology Lipoproteins HDL3 Scavenger Receptors Class B Basal plasma membrane Trophoblasts Endocrinology medicine.anatomical_structure Reproductive Medicine chemistry Membrane protein Dihydroalprenolol lipids (amino acids peptides and proteins) Female Lipoproteins HDL Developmental Biology |
| Zdroj: | Placenta. 20(7) |
| ISSN: | 0143-4004 |
| Popis: | It is now known that rapid placental and fetal development is associated with elevated levels of circulating high density lipoprotein (HDL) in pregnant women. The main structure implicated in the maternal-fetal exchange is the syncytiotrophoblast, composed of a brush border membrane (BBM), facing the mother, and a basal plasma membrane (BPM), facing the fetus. In order to understand the mechanisms controlling the placental and fetal supplies of cholesterol, we purified both BBM and BPM and verified the presence of HDL binding sites in these membranes. Binding studies using(125)I-HDL(3)show a single affinity binding site on BPM which has a dissociation constant (K(d)) of 3.45+/-0.43 microg protein/ml and a maximal binding capacity (B(max)) of 5.46+/-1.69 microg protein/mg membrane proteins. In BBM, we observed two affinity binding sites, one with a K(d)of 0.62+/-0.03 microg protein/ml and another one with a K(d)of 6.57+/-0.87 microg protein/ml. Their B(max)values were 0.54+/-0.11 and 2.34+/-0.39 microg of HDL(3)/mg membrane proteins, respectively. CLA-1, a putative HDL-receptor of 85 kDa, was detected on both BPM and BBM, together with two apo A-l binding sites of 110 and 96 kDa on BPM and BBM, respectively. These results provide further evidence that human placenta possesses specific sites for HDL binding, underlining the important role of maternal HDL in the transfer of cholesterol from the maternal circulation to the placenta and the fetus. |
| Databáze: | OpenAIRE |
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