Biofilm formation of Vibrio vulnificus is initiated by adherence of flagellated cells to surfaces, and then flagellum-driven motility is not necessary during biofilm maturation. Once matured biofilms are constructed, cells become flagellated and swim to disperse from biofilms. As a consequence, timely regulations of the flagellar components’ expression are crucial to complete a biofilm life-cycle. In this study, we demonstrated that flagellins’ production is regulated in a biofilm stage-specific manner, via activities of a protease DegQ and a chaperone FlaJ. Among four flagellin subunits for V. vulnificus filament, FlaC had the highest affinities to hook-associated proteins, and is critical for maturating flagellum, showed the least susceptibility to DegQ due to the presence of methionine residues in its DegQ-sensitive domains, ND1 and CD0. Therefore, differential regulation by DegQ and FlaJ controls the cytoplasmic stability of flagellins, which further determines the motility-dependent, stage-specific development of biofilms.

创伤弧菌的生物膜形成是由鞭毛细胞粘附到表面开始的，然后在生物膜成熟过程中不需要鞭毛驱动的运动。一旦构建了成熟的生物膜，细胞就会变成鞭毛并游动以从生物膜中分散。因此，及时调节鞭毛成分的表达对于完成生物膜生命周期至关重要。在这项研究中，我们证明了鞭毛蛋白的产生通过蛋白酶 DegQ 和分子伴侣 FlaJ 的活性以生物膜阶段特定的方式受到调节。在创伤弧菌的四个鞭毛蛋白亚基中在细丝中，FlaC 对钩相关蛋白的亲和力最高，对成熟鞭毛至关重要，由于其 DegQ 敏感结构域 ND1 和 CD0 中存在甲硫氨酸残基，因此对 DegQ 的敏感性最低。因此，DegQ 和 FlaJ 的差异调节控制鞭毛蛋白的细胞质稳定性，这进一步决定了生物膜的运动依赖性、阶段特异性发展。