Characterization of CLA-1, a Human Homologue of Rodent Scavenger Receptor BI, as a Receptor for High Density Lipoprotein and Apoptotic Thymocytes

作者：Koji Murao, Valeska Terpstra, Simone R. Green, Nonna Kondratenko, Daniel Howard Steinberg, Oswald Quehenberger · 发表于：Journal of Biological Chemistry · 年份：1997 · DOI：10.1074/jbc.272.28.17551 · 被引用次数：321 · 研究领域：Cholesterol and Lipid Metabolism、Cancer, Lipids, and Metabolism、Peroxisome Proliferator-Activated Receptors

Recently, a murine scavenger receptor type B class I (SR-BI) was identified that binds high density lipoprotein (HDL) and mediates the selective uptake of cholesterol esters. The human CD36 and LIMPII analogous-1 (CLA-1) receptor shows high sequence homology with SR-BI, but their functional relationship has not been determined. Transfected cells expressing CLA-1 bound HDL with a Kd of about 35 microg/ml, similar to the Kd for HDL binding to rodent SR-BI. This binding resulted in an intracellular accumulation of HDL-derived [3H]cholesterol esters without internalization or degradation of 125I-apolipoprotein. CLA-1 was strongly expressed in the adrenal gland and was also abundant in liver and testis, suggesting that CLA-1, like SR-BI, could play a role in the metabolism of HDL. However, CLA-1 was also expressed in monocytes and, like SR-BI, recognized modified forms of low density lipoproteins as well as native LDL and anionic phospholipids. These findings suggest that CLA-1 might have additional physiological functions. We found that CLA-1 recognizes apoptotic thymocytes. Our results demonstrate that CLA-1, a close structural homologue of SR-BI, is also functionally related to SR-BI and may play an important role as a "docking receptor" for HDL in connection with selective uptake of cholesterol esters. An additional role in recognition of damaged cells is suggested by these studies.