Busche Roger, Riordan John R, Tümmler Burkhard
Institute for Biophysical Chemistry and Structural Biochemistry, Fritz-Hartmann-Centre for Medical Research, Hannover Medical School, Germany.
Department of Biochemistry and Biophysics and Cystic Fibrosis Center, University of North Carolina-Chapel Hill, NC, USA.
FEBS Lett. 2025 Aug;599(15):2167-2178. doi: 10.1002/1873-3468.70083. Epub 2025 May 31.
Cryo-electron microscopy has yielded high-resolution structural data of the multidrug efflux transporter P-glycoprotein (ABCB1), but its direct and indirect interactions within the native membrane environment have remained largely unexplored. Here, we compared the fluidity gradients of plasma membranes of the drug-sensitive CHO cell line AuxB1 and its P-glycoprotein overexpressing derivative B30 by fluorescence anisotropy of embedded n-(9-anthroyloxy) fatty acid probes (n = 2, 7, 9, 12, 16) in the temperature range of 10-50 °C. The shape of the temperature profiles of probe mobility was comparable in AuxB1 and B30 membranes, but did not match. Overexpression of P-glycoprotein smoothened the transversal gradient of the out-of-plane mode of rotation of the probes, which may facilitate the partitioning of hydrophobic drugs into the membrane and thereby increase the speed of P-glycoprotein to pump the drug out of the cell.
冷冻电子显微镜已获得多药外排转运蛋白P-糖蛋白（ABCB1）的高分辨率结构数据，但其在天然膜环境中的直接和间接相互作用在很大程度上仍未得到探索。在此，我们通过嵌入的n-（9-蒽氧基）脂肪酸探针（n = 2、7、9、12、16）在10-50°C温度范围内的荧光各向异性，比较了药物敏感的CHO细胞系AuxB1及其过表达P-糖蛋白的衍生物B30的质膜流动性梯度。AuxB1和B30膜中探针迁移率的温度曲线形状具有可比性，但并不匹配。P-糖蛋白的过表达使探针平面外旋转模式的横向梯度变得平滑，这可能有助于疏水性药物分配到膜中，从而提高P-糖蛋白将药物泵出细胞的速度。
