FACM Unit, Louvain Drug Research Institute & Université catholique de Louvain, 1200, Brussels, Belgium.
CELL Unit, de Duve Institute & Université catholique de Louvain, 1200, Brussels, Belgium.
Sci Rep. 2017 Jun 27;7(1):4264. doi: 10.1038/s41598-017-04388-z.
Although lipid domains have been evidenced in several living cell plasma membranes, their roles remain largely unclear. We here investigated whether they could contribute to function-associated cell (re)shaping. To address this question, we used erythrocytes as cellular model since they (i) exhibit a specific biconcave shape, allowing for reversible deformation in blood circulation, which is lost by membrane vesiculation upon aging; and (ii) display at their outer plasma membrane leaflet two types of submicrometric domains differently enriched in cholesterol and sphingomyelin. We here reveal the specific association of cholesterol- and sphingomyelin-enriched domains with distinct curvature areas of the erythrocyte biconcave membrane. Upon erythrocyte deformation, cholesterol-enriched domains gathered in high curvature areas. In contrast, sphingomyelin-enriched domains increased in abundance upon calcium efflux during shape restoration. Upon erythrocyte storage at 4 °C (to mimick aging), lipid domains appeared as specific vesiculation sites. Altogether, our data indicate that lipid domains could contribute to erythrocyte function-associated (re)shaping.
尽管脂质域已在几种活细胞的质膜中得到证实，但它们的作用仍很大程度上不清楚。我们在这里研究了它们是否可以有助于与功能相关的细胞（再）塑形。为了解决这个问题，我们使用红细胞作为细胞模型，因为它们 (i) 表现出特定的双凹形状，允许在血液循环中进行可逆变形，而在老化时通过膜囊泡化会失去这种变形；和 (ii) 在其外质膜小叶上显示两种类型的亚微观域，分别富含胆固醇和鞘磷脂。我们在这里揭示了胆固醇和鞘磷脂富集域与红细胞双凹膜的不同曲率区域的特异性关联。在红细胞变形时，富含胆固醇的域聚集在高曲率区域。相比之下，在形状恢复过程中钙流出时，富含鞘磷脂的域的丰度增加。在 4°C 下储存红细胞（模拟老化）时，脂质域呈现出特定的囊泡化位点。总之，我们的数据表明，脂质域可能有助于与红细胞功能相关的（再）塑形。
