Deng Zhao, Zink Tiffany, Chen Huan-yuan, Walters Deron, Liu Fu-tong, Liu Gang-yu
Department of Chemistry, University of California, Davis, California, USA.
Biophys J. 2009 Feb 18;96(4):1629-39. doi: 10.1016/j.bpj.2008.11.015.
Degranulation of bone marrow-derived mast cells (BMMCs) triggered by antigens (e.g., 2,4-dinitrophenylated bovine serum albumin (DNP-BSA) and secretagogues (e.g., poly-L-lysine) was investigated by combined atomic force microscopy (AFM) and laser scanning confocal microscopy (LSCM). This combination enables the simultaneous visualization and correlation of membrane morphology with cytoskeletal actin arrangement and intracellular granules. Two degranulation mechanisms and detailed membrane structures that directly corresponded to the two stimuli were revealed. In DNP-BSA triggered activation, characteristic membrane ridges formed in accordance with the rearrangement of underlying F-actin networks. Individual granules were visualized after they released their contents, indicating a "kiss-and-run" pathway. In BMMCs stimulated by poly-L-lysine, lamellopodia and filopodia were observed in association with the F-actin assemblies at and near the cell periphery, whereas craters were observed on the central membrane lacking F-actin. These craters represent a new membrane feature resulting from the "kiss-and-merge" granule fusion. This work provides what we believe is important new insight into the local membrane structures in correlation with the cytoskeleton arrangement and detailed degranulation processes.
通过结合原子力显微镜（AFM）和激光扫描共聚焦显微镜（LSCM），研究了抗原（如2,4 - 二硝基苯基化牛血清白蛋白（DNP - BSA））和促分泌剂（如聚 - L - 赖氨酸）触发的骨髓来源肥大细胞（BMMCs）的脱颗粒过程。这种结合能够同时观察膜形态与细胞骨架肌动蛋白排列以及细胞内颗粒的相关性。揭示了两种脱颗粒机制以及与两种刺激直接对应的详细膜结构。在DNP - BSA触发的激活过程中，特征性的膜嵴根据底层F - 肌动蛋白网络的重排而形成。单个颗粒在释放其内容物后可见，表明存在“亲吻并跑”途径。在聚 - L - 赖氨酸刺激的BMMCs中，在细胞周边及附近观察到与F - 肌动蛋白组装相关的片状伪足和丝状伪足，而在缺乏F - 肌动蛋白的中央膜上观察到凹坑。这些凹坑代表了由“亲吻并融合”颗粒融合产生的新膜特征。这项工作为我们认为的与细胞骨架排列和详细脱颗粒过程相关的局部膜结构提供了重要的新见解。
