Shimaoka T, Kume N, Minami M, Hayashida K, Kataoka H, Kita T, Yonehara S
Institute for Virus Research and Graduate School of Medicine, Kyoto University, Sakyo-ku, Kyoto 606-8507, Japan.
J Biol Chem. 2000 Dec 29;275(52):40663-6. doi: 10.1074/jbc.C000761200.
Receptor-mediated endocytosis of oxidized low density lipoprotein (OxLDL) by macrophages has been implicated in foam cell transformation in the process of atherogenesis. Although several scavenger receptor molecules, including class A scavenger receptors and CD36, have been identified as OxLDL receptors on macrophages, additional molecules on macrophages may also be involved in the recognition of OxLDL. From a cDNA library of phorbol 12-myristate 13-acetate-stimulated THP-1 cells, we isolated a cDNA encoding a novel protein designated SR-PSOX (scavenger receptor that binds phosphatidylserine and oxidized lipoprotein), which acts as a receptor for OxLDL. SR-PSOX was a type I membrane protein consisting of 254 amino acids, expression of which was shown on human and murine macrophages with a molecular mass of 30 kDa. SR-PSOX could specifically bind with high affinity, internalize, and degrade OxLDL. The recognition of OxLDL was blocked by polyinosinic acid and dextran sulfate but not by acetylated low density lipoprotein. Taken together, SR-PSOX is a novel class of molecule belonging to the scavenger receptor family, which may play important roles in pathophysiology including atherogenesis.
巨噬细胞对氧化型低密度脂蛋白（OxLDL）的受体介导内吞作用与动脉粥样硬化形成过程中的泡沫细胞转化有关。尽管已鉴定出几种清道夫受体分子，包括A类清道夫受体和CD36，可作为巨噬细胞上的OxLDL受体，但巨噬细胞上的其他分子可能也参与了对OxLDL的识别。我们从佛波醇12 -肉豆蔻酸酯13 -乙酸酯刺激的THP - 1细胞的cDNA文库中分离出一个编码新型蛋白的cDNA，该蛋白命名为SR - PSOX（结合磷脂酰丝氨酸和氧化脂蛋白的清道夫受体），它可作为OxLDL的受体。SR - PSOX是一种由254个氨基酸组成的I型膜蛋白，在人和小鼠巨噬细胞上表达，分子量为30 kDa。SR - PSOX能以高亲和力特异性结合、内化并降解OxLDL。OxLDL的识别被多聚肌苷酸和硫酸葡聚糖阻断，但不被乙酰化低密度脂蛋白阻断。综上所述，SR - PSOX是清道夫受体家族中的一类新型分子，可能在包括动脉粥样硬化形成在内的病理生理学中发挥重要作用。
