Collaboration of FlhF and FlhG to regulate polar-flagella number and localization in Vibrio alginolyticus

• Published in: Microbiology (Society for General Microbiology) Vol. 154; no. 5; pp. 1390 - 1399
• Main Authors: Kusumoto, Akiko, Shinohara, Akari, Terashima, Hiroyuki, Kojima, Seiji, Yakushi, Toshiharu, Homma, Michio
• Format: Journal Article
• Language: English
• Published: Reading Soc General Microbiol 01-05-2008; Society for General Microbiology
• Subjects: Artificial Gene Fusion; Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Bacteriology; Biological and medical sciences; Flagella - genetics; Flagella - physiology; Flagella - ultrastructure; Fundamental and applied biological sciences. Psychology; Gene Deletion; Gene Expression Regulation, Bacterial; Green Fluorescent Proteins - analysis; Green Fluorescent Proteins - genetics; Immunoprecipitation; Locomotion; Microbiology; Microscopy, Electron, Transmission; Miscellaneous; Models, Biological; Monomeric GTP-Binding Proteins - genetics; Monomeric GTP-Binding Proteins - metabolism; Protein Interaction Mapping; Recombinant Fusion Proteins - analysis; Recombinant Fusion Proteins - genetics; Staining and Labeling - methods; Vibrio alginolyticus; Vibrio alginolyticus - chemistry; Vibrio alginolyticus - genetics; Vibrio alginolyticus - physiology; Vibrio alginolyticus - ultrastructure; Bacteria; Vibrionaceae; Regulation(control); Vibrio alginolyticus; Localization; Flagellum
• ISSN: 1350-0872; 1465-2080
• DOI: 10.1099/mic.0.2007/012641-0

1 Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-Ku, Nagoya 464-8602, Japan
2 Soft Nano-Machine Project, CREST, JST, Japan
Correspondence Michio Homma g44416a{at}cc.nagoya-u.ac.jp
Precise regulation of the number and placement of flagella is critical for the mono-polar-flagellated bacterium Vibrio alginolyticus to swim efficiently. We have shown previously that the number of polar flagella is positively regulated by FlhF and negatively regulated by FlhG. We now show that flhF cells are non-flagellated as are most flhFG cells; however, some of the flhFG cells have several flagella at lateral positions. We found that FlhF–GFP was localized at the flagellated pole, and its polar localization was seen more intensely in flhFG cells. On the other hand, most of the FlhG–GFP was diffused throughout the cytoplasm, although some was localized at the pole. To investigate the FlhF–FlhG interaction, immunoprecipitation was performed by using an anti-FlhF antibody, and FlhG co-precipitated with FlhF. From these results we propose a model in which FlhF localization at the pole determines polar location and production of a flagellum, FlhG interacts with FlhF to prevent FlhF from localizing at the pole, and thus FlhG negatively regulates flagellar number in V. alginolyticus cells.
Present address: Department of Bioscience and Biotechnology, Faculty of Agriculture, Shinshu University, 8304 Minamiminowa, Nagano 399-4598, Japan.