Epidermal growth factor receptor 2 (ErbB2) is found overexpressed in several cancers, such as gastric, and breast cancer, and is, therefore, an important therapeutic target. ErbB2 plays a central role in cancer cell invasiveness, and is associated with cytoskeletal reorganization. In order to study the spatial correlation of single ErbB2 proteins and actin filaments, we applied correlative fluorescence microscopy (FM), and scanning transmission electron microscopy (STEM) to image specifically labeled SKBR3 breast cancer cells. The breast cancer cells were grown on microchips, transformed to express an actin-green fluorescent protein (GFP) fusion protein, and labeled with quantum dot (QD) nanoparticles attached to specific anti-ErbB2 Affibodies. FM was performed to identify cellular regions with spatially correlated actin and ErbB2 expression. For STEM of the intact plasma membrane of whole cells, the cells were fixed and covered with graphene. Spatial distribution patterns of ErbB2 in the actin rich ruffled membrane regions were examined, and compared to adjacent actin-low regions of the same cell, revealing an association of putative signaling active ErbB2 homodimers with actin-rich regions. ErbB2 homodimers were found absent from actin-low membrane regions, as well as after treatment of cells with Cytochalasin D, which breaks up larger actin filaments. In both latter data sets, a significant inter-label distance of 36 nm was identified, possibly indicating an indirect attachment to helical actin filaments via the formation of heterodimers of ErbB2 with epidermal growth factor receptor (EGFR). The possible attachment to actin filaments was further explored by identifying linear QD-chains in actin-rich regions, which also showed an inter-label distance of 36 nm.

发现表皮生长因子受体2（ErbB2）在几种癌症（例如胃癌和乳腺癌）中过表达，因此是重要的治疗靶标。ErbB2在癌细胞侵袭中起着核心作用，并与细胞骨架重组有关。为了研究单个ErbB2蛋白和肌动蛋白丝的空间相关性，我们应用了相关荧光显微镜（FM）和扫描透射电子显微镜（STEM）对专门标记的SKBR3乳腺癌细胞进行成像。乳腺癌细胞在微芯片上生长，转化为表达肌动蛋白-绿色荧光蛋白（GFP）融合蛋白，并用附着于特定抗ErbB2亲和体的量子点（QD）纳米颗粒标记。进行FM以鉴定具有空间相关肌动蛋白和ErbB2表达的细胞区域。对于整个细胞完整质膜的STEM，将细胞固定并用石墨烯覆盖。检查了肌动蛋白丰富的褶膜区域中ErbB2的空间分布模式，并与同一细胞的相邻肌动蛋白低区域进行了比较，揭示了假定的信号活性ErbB2同型二聚体与肌动蛋白丰富的区域之间的联系。发现在肌动蛋白低膜区域以及用细胞松弛素D处理细胞后，ErbB2同型二聚体不存在，这会破坏较大的肌动蛋白丝。在后两个数据集中，鉴定到的显着标记间距离为36 nm，这可能表明通过与表皮生长因子受体（EGFR）形成ErbB2异二聚体间接连接到螺旋肌动蛋白丝。