Fu Yilin, Hua Peiyan, Lou Yan, Li Zihao, Jia Meng, Jing Yingying, Cai Mingjun, Wang Hongda, Tong Ti, Gao Jing
The Second Hospital of Jilin University, No. 218, Ziqiang Road, Changchun, Jilin 130041, China.
State Key Laboratory of Electroanalytical Chemistry, Research Center of Biomembranomics, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, No. 5625, Renmin Street, Changchun, Jilin 130022, China.
ACS Omega. 2020 Dec 8;5(50):32456-32465. doi: 10.1021/acsomega.0c04597. eCollection 2020 Dec 22.
The transmembrane glycoprotein Trop2 plays important roles in various types of human cancers, especially lung cancer. Although it has been found to form clusters on cancer cell membranes, the factors that affect its clustering are not yet fully understood. Here, using direct stochastic optical reconstruction microscopy (dSTORM), we found that Trop2 generated more, larger, and denser clusters on apical cell membranes than on basal membranes and that the differences might be related to the different membrane structures. Moreover, dual-color dSTORM imaging revealed significant colocalization of Trop2 and lipid rafts, and methyl-β-cyclodextrin disruption dramatically impaired the formation of Trop2 clusters, indicating a key role of lipid rafts in Trop2 clustering. Additionally, depolymerization of the actin cytoskeleton decreased Trop2 cluster numbers and areas, revealing that actin can stabilize the clusters. More importantly, stimulation of Trop2 in cancer cells hardly changed the cluster morphology, suggesting that Trop2 is activated and forms clusters in cancer cells. Altogether, our work links the spatial organization of Trop2 to different membrane structures and Trop activation and uncovers the essential roles of lipid rafts and actin in Trop2 cluster maintenance.
跨膜糖蛋白Trop2在各类人类癌症尤其是肺癌中发挥着重要作用。尽管已发现它在癌细胞膜上形成簇，但影响其簇形成的因素尚未完全明确。在此，我们使用直接随机光学重建显微镜（dSTORM）发现，Trop2在顶端细胞膜上形成的簇比在基底膜上更多、更大且更密集，这些差异可能与不同的膜结构有关。此外，双色dSTORM成像显示Trop2与脂筏有显著共定位，甲基-β-环糊精破坏显著损害了Trop2簇的形成，表明脂筏在Trop2簇形成中起关键作用。此外，肌动蛋白细胞骨架的解聚减少了Trop2簇的数量和面积，表明肌动蛋白可稳定这些簇。更重要的是，刺激癌细胞中的Trop2几乎不会改变簇的形态，这表明Trop2在癌细胞中被激活并形成簇。总之，我们的工作将Trop2的空间组织与不同的膜结构及Trop激活联系起来，并揭示了脂筏和肌动蛋白在维持Trop2簇中的重要作用。
