Axmann Markus, Plochberger Birgit, Mikula Mario, Weber Florian, Strobl Witta Monika, Stangl Herbert
School of Medical Engineering and Applied Social Sciences, University of Applied Sciences Upper Austria, Garnisonstrasse 21, 4020 Linz, Austria.
Center for Pathobiochemistry and Genetics, Institute for Medical Genetics, Medical University of Vienna, Währingerstrasse 10, 1090 Vienna, Austria.
Membranes (Basel). 2021 Nov 17;11(11):882. doi: 10.3390/membranes11110882.
Cholesterol is one of the main constituents of plasma membranes; thus, its supply is of utmost importance. This review covers the known mechanisms of cholesterol transfer from circulating lipoprotein particles to the plasma membrane, and vice versa. To achieve homeostasis, the human body utilizes cellular de novo synthesis and extracellular transport particles for supply of cholesterol and other lipids via the blood stream. These lipoprotein particles can be classified according to their density: chylomicrons, very low, low, and high-density lipoprotein (VLDL, LDL, and HDL, respectively). They deliver and receive their lipid loads, most importantly cholesterol, to and from cells by several redundant routes. Defects in one of these pathways (e.g., due to mutations in receptors) usually are not immediately fatal. Several redundant pathways, at least temporarily, compensate for the loss of one or more of them, but the defects trigger systemic diseases, such as atherosclerosis later on. Recently, intracellular membrane-membrane contact sites were shown to be involved in intracellular cholesterol transfer and the plasma membrane itself has been proposed to act as a binding site for lipoprotein-mediated cargo unloading.
胆固醇是质膜的主要成分之一，因此其供应至关重要。本综述涵盖了胆固醇从循环脂蛋白颗粒转移至质膜以及反之亦然的已知机制。为实现体内平衡，人体利用细胞内从头合成以及细胞外转运颗粒，通过血流供应胆固醇和其他脂质。这些脂蛋白颗粒可根据其密度进行分类：乳糜微粒、极低密度、低密度和高密度脂蛋白（分别为VLDL、LDL和HDL）。它们通过多种冗余途径向细胞输送脂质负荷（最重要的是胆固醇）并从细胞接收脂质负荷。这些途径之一的缺陷（例如，由于受体突变）通常不会立即致命。几种冗余途径至少在短期内可补偿其中一种或多种途径的缺失，但这些缺陷随后会引发全身性疾病，如动脉粥样硬化。最近，细胞内膜-膜接触位点被证明参与细胞内胆固醇转移，并且有人提出质膜本身可作为脂蛋白介导的货物卸载的结合位点。
