| First Author | Temel RE | Year | 2003 |
| Journal | J Biol Chem | Volume | 278 |
| Issue | 7 | Pages | 4792-9 |
| PubMed ID | 12473673 | Mgi Jnum | J:81905 |
| Mgi Id | MGI:2450212 | Doi | 10.1074/jbc.M208160200 |
| Citation | Temel RE, et al. (2003) Enhancement of Scavenger Receptor Class B Type I-mediated Selective Cholesteryl Ester Uptake from apoA-I-/- High Density Lipoprotein (HDL) by Apolipoprotein A-I Requires HDL Reorganization by Lecithin Cholesterol Acyltransferase. J Biol Chem 278(7):4792-9 |
| abstractText | The severe depletion of cholesteryl ester (CE) in adrenocortical cells of apoA-I(-/-) mice suggests that apolipoprotein (apo) A-I plays an important role in the high density lipoprotein (HDL) CE selective uptake process mediated by scavenger receptor BI (SR-BI) in vivo. A recent study showed that apoA-I(-/-) HDL binds to SR-BI with the same affinity as apoA-I(+/+) HDL, but apoA-I(-/-) HDL has a decreased V(max) for CE transfer from the HDL particle to adrenal cells. The present study was designed to determine the basis for the reduced selective uptake of CE from apoA-I(-/-) HDL. Variations in apoA-I(-/-) HDL particle diameter, free cholesterol or phospholipid content, or the apoE or apoA-II content of apoA-I(-/-) HDL had little effect on HDL CE selective uptake into Y1-BS1 adrenal cells. Lecithin cholesterol acyltransferase treatment alone or addition of apoA-I to apoA-I(-/-) HDL alone also had little effect. However, addition of apoA-I to apoA-I(-/-) HDL in the presence of lecithin cholesterol acyltransferase reorganized the large heterogeneous apoA-I(-/-) HDL to a more discrete particle with enhanced CE selective uptake activity. These results show a unique role for apoA-I in HDL CE selective uptake that is distinct from its role as a ligand for HDL binding to SR-BI. These data suggest that the conformation of apoA-I at the HDL surface is important for the efficient transfer of CE to the cell. |
