Achievements in bacterial flagellar research with focus on <i>Vibrio</i> species

Homma, Michio; Nishikino, Tatsuro; Kojima, Seiji

doi:10.1111/1348-0421.12954

Cited by 20 publications

(18 citation statements)

References 223 publications

(473 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…By rotating these flagella in a screw‐like motion, the bacteria can swim in liquid or swarm to spread on the surface to move toward favorable or away from unfavorable environments to allow for survival. The flagellum is composed of more than 30 proteins (Homma et al, 2022). A given flagellum consists of three components that include a motor that is embedded in the membrane, a filament extending outside of the cell, and a hook connecting the motor and the filament.…”

Section: Introductionmentioning

confidence: 99%

Formation of multiple flagella caused by a mutation of the flagellar rotor protein FliM in Vibrio alginolyticus

et al. 2022

Self Cite

View full text Add to dashboard Cite

Marine bacterium Vibrio alginolyticus forms a single flagellum at a cell pole. In Vibrio, two proteins (GTPase FlhF and ATPase FlhG) regulate the number of flagella. We previously isolated the NMB155 mutant that forms multiple flagella despite the absence of mutations in flhF and flhG. Whole-genome sequencing of NMB155 identified an E9K mutation in FliM that is a component of C-ring in the flagellar rotor. Mutations in FliM result in defects in flagellar formation (fla) and flagellar rotation (che or mot); however, there are a few reports indicating that FliM mutations increase the number of flagella. Here, we determined that the E9K mutation confers the multi-flagellar phenotype and also the che phenotype. The co-expression of wild-type FliM and FliM-E9K indicated that they were competitive in regard to determining the flagellar number. The ATPase activity of FlhG has been correlated with the number of flagella. We observed that the ATPase activity of FlhG was increased by the addition of FliM but not by the addition of FliM-E9K in vitro. This indicates that FliM interacts with FlhG to increase its ATPase activity, and the E9K mutation may inhibit this interaction. FliM may control the ATPase activity of FlhG to properly regulate the number of the polar flagellum at the cell pole.

show abstract

Section: Introductionmentioning

confidence: 99%

Formation of multiple flagella caused by a mutation of the flagellar rotor protein FliM in Vibrio alginolyticus

et al. 2022

Self Cite

View full text Add to dashboard Cite

show abstract

“…The Vibrio regulation and biogenesis of polar flagella have been intensively studied (15). It is an excellent model system for investigating how the flagella location and number are determined.…”

Section: Discussionmentioning

confidence: 99%

Function and structure of FlaK, a master regulator of the polar flagellar genes in marine Vibrio

Homma

Kobayakawa

Hao

et al. 2022

Preprint

Self Cite

View full text Add to dashboard Cite

Vibrio alginolyticus has a flagellum at the cell pole, and the fla genes, involved in its formation, are hierarchically regulated in several classes. FlaK (also called FlrA) is an ortholog of Pseudomonas aeruginosa FleQ, an AAA+ ATPase that functions as a master regulator for all later fla genes. In this study, we conducted mutational analysis of FlaK to examine its ATPase activity, ability to form a multimeric structure, and function in flagellation. We cloned flaK and confirmed that its deletion caused a non-flagellated phenotype. We substituted amino acids at the ATP binding/hydrolysis site and performed putative subunit interfaces in a multimeric structure. Mutations in the aforementioned sites abolished both ATPase activity and the ability of FlaK to induce downstream flagellar gene expression. The L371E mutation, at the putative subunit interface, abolished flagellar gene expression but retained ATPase activity, suggesting that ATP hydrolysis is not sufficient for flagellar gene expression. We also found that FlhG, a negative flagellar biogenesis regulator, suppressed the ATPase activity of FlaK. The 20 FlhG C-terminal residues are critical for reducing FlaK ATPase activity. Chemical crosslinking and size exclusion chromatography revealed that FlaK mostly exists as a dimer in solution and can form multimers, independent of ATP. However, ATP induced the interaction between FlhG and FlaK to form a large complex. The in vivo effects of FlhG on FlaK, such as multimer formation and/or DNA binding, are important for gene regulation.

show abstract

“…In transcription regulation, it has been thought that the flhA, flhF, flhG, and fliA genes form an operon, and according to studies of V. cholerae and V. parahaemolyticus, they are class 2 genes (Fig. S1) (6). The flhA operon is transcribed by FlaK, which is a master regulator of flagellum-related genes.…”

Section: Control Of the Level Of Flhg Protein By The N-terminal Regio...mentioning

confidence: 99%

“…FlhF and FlhG are also known as transcriptional activators and repressors, respectively (4,5). The polar flagellar genes of Vibrio form a regulon consisting of four hierarchies, from class 1 to class 4 operons (6). Expression of the class 2 gene group is controlled by FlaK (called FlrA in V. cholerae and FleQ in Pseudomonas aeruginosa), which functions as a master regulator and belongs to class 1 genes (Fig.…”

Section: Introductionmentioning

confidence: 99%

Functional analysis of the N-terminal region of Vibrio FlhG, a MinD-type ATPase in flagellar number control

Homma

Mizuno

Hao

et al. 2022

The Journal of Biochemistry

Self Cite

View full text Add to dashboard Cite

Summary GTPase FlhF and ATPase FlhG are two key factors involved in regulating the flagellum number in Vibrio alginolyticus. FlhG is a paralog of the Escherichia coli cell division regulator MinD and has a longer N-terminal region than MinD with a conserved DQAxxLR motif. The deletion of this N-terminal region or a Q9A mutation in the DQAxxLR motif prevents FlhG from activating the GTPase activity of FlhF in vitro and causes a multi-flagellation phenotype. The mutant FlhG proteins, especially the N-terminally deleted variant, was remarkably reduced compared to that of the wild-type protein in vivo. When the mutant FlhG was expressed at the same level as the wild-type FlhG, the number of flagella was restored to the wild-type level. Once synthesized in Vibrio cells, the N-terminal region mutation in FlhG seems not to affect the protein stability. We speculated that the flhG translation efficiency is decreased by N-terminal mutation. Our results suggest that the N-terminal region of FlhG controls the number of flagella by adjusting the FlhF activity and the amount of FlhG in vivo. We speculate that the regulation by FlhG, achieved through transcription by the master regulator FlaK, is affected by the mutations, resulting in reduced flagellar formation by FlhF.

show abstract

Achievements in bacterial flagellar research with focus on Vibrio species

Cited by 20 publications

References 223 publications

Formation of multiple flagella caused by a mutation of the flagellar rotor protein FliM in Vibrio alginolyticus

Formation of multiple flagella caused by a mutation of the flagellar rotor protein FliM in Vibrio alginolyticus

Function and structure of FlaK, a master regulator of the polar flagellar genes in marine Vibrio

Functional analysis of the N-terminal region of Vibrio FlhG, a MinD-type ATPase in flagellar number control

Contact Info

Product

Resources

About