Sung Yun-Sing, Hong De-Fa, Chang Yi-Ren
Department of Physics, National Taiwan Normal University, Taipei, 116, Taiwan.
Biochem Biophys Rep. 2025 May 14;42:102051. doi: 10.1016/j.bbrep.2025.102051. eCollection 2025 Jun.
The assembly and spatial organization of flagellar basal bodies in are crucial for motility and chemotaxis. Using fluorescence and single-molecule microscopy, we demonstrate that key basal body proteins, FliF and FlhA, self-organize into clusters from low to high expression conditions. Rather than forming new basal bodies, excess proteins accumulate around pre-existing structures, suggesting an autocatalytic mechanism. It is confirmed that clustering occurs even at low protein levels, indicating an intrinsic organizational principle rather than an artifact of overexpression. Fluorescence recovery after photobleaching (FRAP) revealed dynamic protein exchange within clusters, supporting a diffusion-capture model. Single-molecule analysis showed that FlhA actively remodels clusters, while FliF stabilizes them. 3D imaging suggested that basal body positioning optimizes flagellar distribution for efficient motility. These findings highlight a robust mechanism that regulates basal body positioning and flagellar assembly, ensuring adaptability to varying cellular conditions.
鞭毛基体的组装和空间组织对于运动性和趋化性至关重要。利用荧光和单分子显微镜技术，我们证明关键的基体蛋白FliF和FlhA在从低到高表达条件下会自组织成簇。多余的蛋白质并非形成新的基体，而是在预先存在的结构周围积累，这表明存在一种自催化机制。已证实即使在低蛋白水平下也会发生聚集，这表明存在一种内在的组织原则，而非过表达的假象。光漂白后荧光恢复（FRAP）揭示了簇内蛋白质的动态交换，支持扩散捕获模型。单分子分析表明，FlhA积极重塑簇，而FliF使其稳定。三维成像表明，基体定位优化了鞭毛分布以实现高效运动。这些发现突出了一种强大的机制，该机制调节基体定位和鞭毛组装，确保对不同细胞条件的适应性。
