Sterol-binding proteins and endosomal cholesterol transport

Endosomal compartments sort and deliver exogenous lipoprotein-derived cholesterol to the endoplasmic reticulum for regulating cellular cholesterol homeostasis.A large number of studies have focused on the removal of endosomal cholesterol,since its accumulation leads to devastating human diseases.Recent studies suggest that cytoplasmic sterol-binding proteins may be involved in endosomal cholesterol transport.In particular,endosome/lysosome-localized or-associated cholesterol-binding proteins may serve as key mediators of cholesterol removal in a non-vesicular manner.Further characterization of these cholesterol-binding proteins will shed light on the molecular mechanisms that regulate endosomal cholesterol sorting.

细胞内胆固醇运输

作为生物膜的重要成分,细胞内不同膜上胆固醇含量的高低直接影响生物膜的生物物理特性和细胞信号的传递,与细胞正常的生理功能密切相关。外源内吞的胆固醇和内源合成的胆固醇通过囊泡介导和非囊泡介导的胆固醇运输途径在不同细胞膜之间转运,从而维持了不同细胞器上胆固醇的浓度梯度。一系列胆固醇结合和转运蛋白在细胞内胆固醇的运输中发挥了重要作用。本文旨在总结细胞内胆固醇运输途径与参与胆固醇运输的重要分子及相关作用机制。