Yokoyama S
Department of Biochemistry I, Nagoya City University Medical School, Japan.
Nihon Yakurigaku Zasshi. 1998 Feb;111(2):77-85. doi: 10.1254/fpj.111.77.
Cholesterol efflux is one of the essential events in cellular cholesterol homeostasis since peripheral cells do not catabolize the cholesterol molecule. There are two distinct mechanisms for the efflux. One is the non-specific classical pathway mediated by physicochemical diffusion of cholesterol through the aqueous phase and its esterification on high density lipoprotein (HDL) by lecithin: cholesterol acyltransferase (LCAT). The other is the specific and biological pathway in which new HDL particles are generated from cellular lipid by the direct interaction of cell membrane and amphiphilic apolipoproteins that have dissociated from HDL. The latter reaction consists of binding of apolipoprotein to the specific binding site of the cellular surface and subsequent mobilization of intracellular cholesterol for the HDL generation mediated by intracellular signal transduction. This reaction seems to be a major source of plasma HDL.
胆固醇流出是细胞胆固醇稳态中的重要事件之一，因为外周细胞不会分解胆固醇分子。胆固醇流出有两种不同的机制。一种是非特异性经典途径，由胆固醇通过水相的物理化学扩散介导，并通过卵磷脂胆固醇酰基转移酶（LCAT）在高密度脂蛋白（HDL）上进行酯化。另一种是特异性生物学途径，其中新的HDL颗粒通过细胞膜与已从HDL解离的两亲性载脂蛋白的直接相互作用从细胞脂质中产生。后一种反应包括载脂蛋白与细胞表面特异性结合位点的结合，以及随后通过细胞内信号转导介导的细胞内胆固醇动员以生成HDL。这种反应似乎是血浆HDL的主要来源。
