title: Investigation into FlhFG reveals distinct features of FlhF in regulating flagellum polarity in Shewanella oneidensis.
abstract: Rod-shaped bacterial cells are polarized, with many organelles confined to a polar cellular site. In polar flagellates, FlhF and FlhG, a multiple-domain (B-N-G) GTPase and a MinD-like ATPase respectively, function as a cognate pair to regulate flagellar localization and number as revealed in Vibrio and Pseudomonas species. In this study, we show that FlhFG of Shewanella oneidensis (SoFlhFG), a monotrichous γ-proteobacterium renowned for respiratory diversity, also play an important role in the flagellar polar placement and number control. Despite this, SoFlhFG exhibit distinct features that are not observed in the characterized counterparts. Most strikingly, the G domain of SoFlhF determines the polar placement, contrasting the N domain of the Vibrio cholerae FlhF. The SoFlhF N domain in fact counteracts the function of the G domain with respect to the terminal targeting in the absence of the B domain. We further show that GTPase activity of SoFlhF is essential for motility but not positioning. Overall, our results suggest that mechanisms underlying the polar placement of organelles appear to be diverse, even for evolutionally relatively conserved flagellum.
authors.affiliation: Institute of Microbiology and College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, 310058, China.
authors.forename: Tong
authors.initials: T
authors.lastname: Gao
authors.affiliation: Institute of Microbiology and College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, 310058, China.
authors.forename: Miaomiao
authors.initials: M
authors.lastname: Shi
authors.affiliation: Institute of Microbiology and College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, 310058, China.
authors.forename: Lili
authors.initials: L
authors.lastname: Ju
authors.affiliation: Institute of Microbiology and College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, 310058, China.
authors.forename: Haichun
authors.initials: H
authors.lastname: Gao
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D016764:Cell Polarity; D005407:Flagella / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D056726:Genetic Association Studies; D020559:Monomeric GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D010641:Phenotype; D020592:Shewanella / Q000235:genetics / Q000378:metabolism / Q000502:physiology*
chemical_list: D001426:Bacterial Proteins; C078317:flhF protein, Bacteria; D020559:Monomeric GTP-Binding Proteins