Cellular differences in lipoprotein lipase-mediated uptake of low density lipoproteins
| Autor: | Joseph C. Obunike, I J Edwards, William D. Wagner, S C Rumsey, Ira J. Goldberg, Richard J. Deckelbaum, Linda K. Curtiss |
|---|---|
| Rok vydání: | 1994 |
| Předmět: |
medicine.medical_specialty
Lipoprotein lipase Apolipoprotein B biology media_common.quotation_subject Cell Biology Heparan sulfate Biochemistry chemistry.chemical_compound Endocrinology chemistry Cell surface receptor Internal medicine LDL receptor medicine biology.protein lipids (amino acids peptides and proteins) Receptor Internalization Molecular Biology Lipoprotein media_common |
| Zdroj: | Journal of Biological Chemistry. 269:13129-13135 |
| ISSN: | 0021-9258 |
| DOI: | 10.1016/s0021-9258(17)36808-4 |
| Popis: | Lipoprotein lipase (LPL) increases the cellular uptake and degradation of LDL by fibroblasts and macrophages via a heparin-sensitive process. The roles of the LDL receptor, LDL receptor-related protein (LRP), and proteoglycans in this process were studied. In up-regulated human fibroblasts, LPL increased degradation of 125I-low density lipoprotein (LDL) (5 micrograms/ml) only 30% during a 6-h incubation at 37 degrees C. Monoclonal antibody 47 (which interacts with the receptor binding region of apoB) decreased LDL degradation 93% in the absence of LPL, but did not reduce the LPL-mediated increase in degradation. In contrast, addition of the 39-kDa receptor-associated protein (RAP) caused a 43% decrease in the LPL-dependent LDL degradation in non-up-regulated fibroblasts. Monoclonal antibody 47 did not decrease LDL degradation by THP-1 macrophages and RAP caused a 30% of pericellular heparan sulfate was lost between 2-4 h of the chase period. Therefore, some of the LPL-mediated LDL degradation in the THP-1 cells could be accounted for by internalization of cell surface proteoglycans. We conclude that LRP, but not the LDL receptor, is involved in LPL-mediated degradation of LDL in fibroblasts. This process is much more rapid in THP-1 cells and in addition to LRP may involve other receptors and internalization of proteoglycans. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|