Abstract

Many ion channels are localized in areas of the plasma membrane enriched in cholesterol and sphingolipids, known as “lipid rafts.” The problem of the interaction of ion channels with rafts is one of the least studied in modern biology and physiology. In this study, we investigated the role of lipid rafts in the membrane localization of TRPV5 calcium channels (transient receptor potential vanilloid, type 5), which we discovered earlier in human T cells of the Jurkat line. Immunofluorescence analysis of cells showed the near-membrane localization of TRPV5 proteins and their colocalization with lipid rafts. Membrane cholesterol reduction with the use of methyl β-cyclodextrin (MbCD) led to a decrease in surface exposure of the channels and their diffuse distribution in the cell cytoplasm. An analysis of cell images obtained by immunoelectron microscopy revealed local clusters of TRPV5 proteins in the form of clusters in the plasma membrane of cells. Extraction of membrane cholesterol and destruction of lipid rafts led to the disappearance of channel clusters and the departure of TRPV5 channels from the plasma membrane of cells into the cytoplasm. On the whole, the results showed that the localization of TRPV5 calcium channels in the form of clusters in the plasma membrane is critically dependent on the level of cholesterol and the integrity of lipid rafts in Jurkat T cells.

中文翻译：

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胆固醇在Jurkat人类T细胞中TRPV5钙离子通道膜的定位中的作用

摘要

许多离子通道位于质膜中富含胆固醇和鞘脂的区域，被称为“脂质筏”。离子通道与筏的相互作用问题是现代生物学和生理学中研究最少的问题之一。在这项研究中，我们调查了脂质筏在TRPV5钙离子通道膜（瞬时受体电位类香草酸，5型）的膜定位中的作用，这是我们先前在Jurkat系的人T细胞中发现的。细胞的免疫荧光分析显示TRPV5蛋白的近膜定位及其与脂质筏的共定位。使用甲基β-环糊精（MbCD）降低膜胆固醇可导致通道表面暴露及其在细胞质中的弥散分布减少。通过免疫电子显微镜获得的细胞图像的分析揭示了TRPV5蛋白的局部簇以细胞质膜中的簇形式存在。膜胆固醇的提取和脂质筏的破坏导致通道簇的消失和TRPV5通道从细胞质膜进入细胞质。总体而言，结果表明，TRPV5钙通道以簇的形式在质膜中定位主要取决于胆固醇水平和Jurkat T细胞中脂质筏的完整性。膜胆固醇的提取和脂质筏的破坏导致通道簇的消失和TRPV5通道从细胞质膜进入细胞质。总体而言，结果表明，TRPV5钙通道以簇的形式在质膜中定位主要取决于胆固醇水平和Jurkat T细胞中脂质筏的完整性。膜胆固醇的提取和脂质筏的破坏导致通道簇的消失和TRPV5通道从细胞质膜进入细胞质。总体而言，结果表明，TRPV5钙通道以质膜形式簇的定位主要取决于胆固醇水平和Jurkat T细胞中脂筏的完整性。