Mazzantini Diletta, Celandroni Francesco, Salvetti Sara, Gueye Sokhna A, Lupetti Antonella, Senesi Sonia, Ghelardi Emilia
Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa Pisa, Italy.
Department of Biology, University of Pisa Pisa, Italy.
Front Microbiol. 2016 Oct 19;7:1644. doi: 10.3389/fmicb.2016.01644. eCollection 2016.
Besides sporulation, can undergo a differentiation process in which short swimmer cells become elongated and hyperflagellated swarmer cells that favor migration of the bacterial community on a surface. The functionally enigmatic flagellar protein FlhF, which is the third paralog of the signal recognition particle (SRP) GTPases Ffh and FtsY, is required for swarming in many bacteria. Previous data showed that FlhF is involved in the control of the number and positioning of flagella in . In this study, analysis of FlhF revealed that this protein presents conserved domains that are typical of SRPs in many organisms and a peculiar N-terminal basic domain. By proteomic analysis, a significant effect of FlhF depletion on the amount of secreted proteins was found with some proteins increased (e.g., B component of the non-hemolytic enterotoxin, cereolysin O, enolase) and others reduced (e.g., flagellin, L component of hemolysin BL, bacillolysin, sphingomyelinase, PC-PLC, PI-PLC, cytotoxin K) in the extracellular proteome of a Δ mutant. Deprivation of FlhF also resulted in significant attenuation in the pathogenicity of this strain in an experimental model of infection in larvae. Our work highlights the multifunctional role of FlhF in , being this protein involved in bacterial flagellation, swarming, protein secretion, and pathogenicity.
除了形成芽孢外，[细菌名称]还可经历分化过程，在此过程中，短游动细胞会变长并成为超鞭毛化的群体游动细胞，这有利于细菌群体在表面迁移。功能神秘的鞭毛蛋白FlhF是信号识别颗粒（SRP）GTP酶Ffh和FtsY的第三个旁系同源物，许多细菌的群体游动都需要它。先前的数据表明，FlhF参与控制[细菌名称]中鞭毛的数量和定位。在本研究中，对[细菌名称]的FlhF分析表明，该蛋白具有许多生物体中SRP典型的保守结构域以及一个特殊的N端碱性结构域。通过蛋白质组学分析，发现缺失FlhF对分泌蛋白的量有显著影响，在Δ突变体的细胞外蛋白质组中，一些蛋白增加（如非溶血肠毒素的B组分、溶血素O、烯醇化酶），而其他蛋白减少（如鞭毛蛋白、溶血素BL的L组分、芽孢杆菌溶素、鞘磷脂酶、PC-PLC、PI-PLC、细胞毒素K）。缺失FlhF还导致该菌株在感染[宿主名称]幼虫的实验模型中的致病性显著减弱。我们的工作突出了FlhF在[细菌名称]中的多功能作用，该蛋白参与细菌鞭毛形成、群体游动、蛋白质分泌和致病性。
