CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500 007, India.
Institut de Pharmacologie et de Biologie Structurale, CNRS, Université de Toulouse (UPS), 31 077 Toulouse, France.
J Phys Chem B. 2022 Sep 8;126(35):6682-6690. doi: 10.1021/acs.jpcb.2c03941. Epub 2022 Aug 16.
G protein-coupled receptors (GPCRs) are signaling hubs in cell membranes that regulate a wide range of physiological processes and are popular drug targets. Serotonin receptors are important members of the GPCR family and are implicated in neuropsychiatric disorders. Cholesterol is a key constituent of higher eukaryotic membranes and is believed to contribute to the segregated distribution of membrane constituents into domains. To explore the role of cholesterol in lateral dynamics of GPCRs, we utilized single particle tracking (SPT) to monitor diffusion of serotonin receptors under acute and chronic cholesterol-depleted conditions. Our results show that the short-term diffusion coefficient of the receptor decreases upon cholesterol depletion, irrespective of the method of cholesterol depletion. Analysis of SPT trajectories revealed that relative populations of receptors undergoing various modes of diffusion change upon cholesterol depletion. Notably, in cholesterol-depleted cells, we observed an increase in the confined population of the receptor accompanied by a reduction in diffusion coefficient for chronic cholesterol depletion. These results are supported by our recent work and present observations that show polymerization of G-actin in response to chronic cholesterol depletion. Taken together, our results bring out the interdependence of cholesterol and actin cytoskeleton in regulating diffusion of GPCRs in membranes.
G 蛋白偶联受体（GPCRs）是细胞膜中的信号枢纽，调节着广泛的生理过程，是热门的药物靶点。5-羟色胺受体是 GPCR 家族的重要成员，与神经精神疾病有关。胆固醇是真核生物膜的重要组成部分，被认为有助于将膜成分分隔成域。为了探索胆固醇在 GPCR 侧向动力学中的作用，我们利用单粒子追踪（SPT）技术监测 5-羟色胺受体在急性和慢性胆固醇耗竭条件下的扩散。我们的结果表明，胆固醇耗竭后受体的短期扩散系数降低，无论胆固醇耗竭的方法如何。SPT 轨迹分析表明，胆固醇耗竭后，经历各种扩散模式的受体的相对种群发生变化。值得注意的是，在胆固醇耗竭的细胞中，我们观察到受体的受限种群增加，同时慢性胆固醇耗竭的扩散系数降低。我们最近的工作和目前的观察结果支持这些结果，表明慢性胆固醇耗竭会导致 G 肌动蛋白聚合。综上所述，我们的结果表明胆固醇和肌动蛋白细胞骨架在调节膜中 GPCR 扩散方面相互依赖。
