Muller C, Shinitzky M
Br J Haematol. 1979 Jul;42(3):355-62. doi: 10.1111/j.1365-2141.1979.tb01143.x.
The hypothesis that modulation of transferrin receptors during haematopoiesis is mediated by changes in the lipid fluidity of the cell membranes was tested in this study with bone marrow cells. Binding conditions were first established, under which internalization of fluorescently-labelled transferrin was reduced to a minimum during the binding assays. Cholesterol depletion, which was achieved by a mild physiological treatment, and which increased the membrane-lipid fluidity, resulted in a substantial increase in the average number of the available transferrin receptors per bone marrow cell. Cholesterol enrichment mediated a converse effect. These findings correlate well with the changes observed in the availability of transferrin receptors and membrane microviscosity during differentiation of erythroid cells. In line with the notion of passive modulation, it is proposed that the transferrin receptor is a cross-membrane protein with a substantial portion facing the cytoplasm.
本研究用骨髓细胞对造血过程中转铁蛋白受体的调节由细胞膜脂质流动性变化介导这一假说进行了验证。首先确定了结合条件，在此条件下，结合试验期间荧光标记转铁蛋白的内化降至最低。通过温和的生理处理实现的胆固醇耗竭增加了膜脂质流动性，导致每个骨髓细胞上可用转铁蛋白受体的平均数量大幅增加。胆固醇富集则产生相反的效果。这些发现与红系细胞分化过程中转铁蛋白受体可用性和膜微粘度的变化密切相关。符合被动调节的概念，有人提出转铁蛋白受体是一种跨膜蛋白，其大部分面向细胞质。
