A flagellum-specific chaperone facilitates assembly of the core type III export apparatus of the bacterial flagellum

Fabiani, Florian; Renault, Thibaud T.; Peters, Britta; Dietsche, Tobias; Galvez, Eric; Guse, Alina; Freier, Karen; Charpentier, Emmanuelle; Strowig, Till; Franz‐Wachtel, Mirita; Maček, Boris; Wagner, Samuel; Hensel, Michael; Erhardt, Marc

doi:10.1371/journal.pbio.2002267

Cited by 56 publications

(66 citation statements)

References 59 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As the export of the rod proteins to the periplasm requires the T3SS export apparatus, this complex ought to be a disassembly product. In the ΔflgG strain, the inner‐membrane sub‐complex was observed in two examples (Fig Q and R) and no (sub‐)complexes related to the flagellar motor could be detected in cells lacking FlhA which is believed to be one of the first proteins to be assembled (Li & Sourjik, ; Fabiani et al , ; Fukumura et al , ).…”

Section: Resultsmentioning

confidence: 99%

“…This is likely because the process of flagellar assembly is so energetically demanding (Paradis et al , ). Our current understanding of flagellar assembly comes from studies of two enteric species of Gram‐negative bacteria, E. coli and Salmonella , which suggest an inside‐to‐outside sequential assembly process starting from the export apparatus, MS‐ring (FliF), followed by the C‐ring proteins, the rod, the P‐ and L‐rings, the hook, and finally the filament (Jones & Macnab, ; Kubori et al , ; Macnab, ; Li & Sourjik, ; Fabiani et al , ; Fukumura et al , ). The process is thought to be a cooperative one, whereby the addition of each new component stabilizes its antecedent (Li & Sourjik, ).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

In situ imaging of the bacterial flagellar motor disassembly and assembly processes

et al. 2019

View full text Add to dashboard Cite

The self‐assembly of cellular macromolecular machines such as the bacterial flagellar motor requires the spatio‐temporal synchronization of gene expression with proper protein localization and association of dozens of protein components. In Salmonella and Escherichia coli, a sequential, outward assembly mechanism has been proposed for the flagellar motor starting from the inner membrane, with the addition of each new component stabilizing the previous one. However, very little is known about flagellar disassembly. Here, using electron cryo‐tomography and sub‐tomogram averaging of intact Legionella pneumophila, Pseudomonas aeruginosa, and Shewanella oneidensis cells, we study flagellar motor disassembly and assembly in situ. We first show that motor disassembly results in stable outer membrane‐embedded sub‐complexes. These sub‐complexes consist of the periplasmic embellished P‐ and L‐rings, and bend the membrane inward while it remains apparently sealed. Additionally, we also observe various intermediates of the assembly process including an inner‐membrane sub‐complex consisting of the C‐ring, MS‐ring, and export apparatus. Finally, we show that the L‐ring is responsible for reshaping the outer membrane, a crucial step in the flagellar assembly process.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

In situ imaging of the bacterial flagellar motor disassembly and assembly processes

et al. 2019

View full text Add to dashboard Cite

show abstract

“…Proteins associated with the cytoplasmic face of the basal body select proteins for export that are then transferred to a set of 5 membrane associated proteins located at the center of the inner-membrane ring. These components (FliP, FliQ, FliR, FlhB, FlhA in the flagellar system and SctR, SctS, SctT, SctU, SctV in 10 injectisomes) are collectively termed the export apparatus (EA) and are absolutely required for the translocation of substrates across the bacterial envelope (Wagner, Konigsmaier et al 2010, Fabiani, Renault et al 2017, Fukumura, Makino et al 2017.…”

Section: Introductionmentioning

confidence: 99%

The structure of an injectisome export gate demonstrates conservation of architecture in the core export gate between flagellar and virulence type three secretion systems

Johnson

Kuhlen

Deme

et al. 2019

Preprint

View full text Add to dashboard Cite

Export of proteins through type three secretion systems (T3SS) is critical for motility and virulence of many major bacterial pathogens. Proteins are exported though a genetically defined export gate complex consisting of three proteins. We have recently shown at 4.2 Å that the flagellar complex of these three putative membrane proteins (FliPQR in flagellar systems, SctRST in virulence systems) assemble into an extra-membrane helical assembly that likely seeds correct assembly of the rod above. Here we present the structure of an equivalent complex from the more fragile Shigella virulence system at 3.5 Å by cryo-electron microscopy. This higher resolution structure reveals further detail and confirms the prediction of 30 structural conservation in this core complex. Analysis of particle heterogeneity also reveals details of how the SctS/FliQ subunits sequentially assemble in the complex.Introduction:

show abstract

“…Flagellar biogenesis begins by activating the transcription of genes encoding components essential for the initial steps in assembly, which include the flagellar type III secretion system (fT3SS), MS ring, and C ring rotor and switch proteins (14)(15)(16)(17)(18)(19)(20). MS and C ring formation around the fT3SS core completes biogenesis of a competent fT3SS for export and assembly of rod and hook components (21)(22)(23)(24)(25). Up to this point, the alternative factor 28 , which is required for transcription of flagellins and other motility genes, is inhibited by the antifactor FlgM (11,13,(26)(27)(28)(29).…”

mentioning

confidence: 99%

A Polar Flagellar Transcriptional Program Mediated by Diverse Two-Component Signal Transduction Systems and Basal Flagellar Proteins Is Broadly Conserved in Polar Flagellates

Burnham

Kolar

Hendrixson

2020

mBio

View full text Add to dashboard Cite

Bacterial flagella are rotating nanomachines required for motility. Flagellar gene expression and protein secretion are coordinated for efficient flagellar biogenesis. Polar flagellates, unlike peritrichous bacteria, commonly order flagellar rod and hook gene transcription as a separate step after production of the MS ring, C ring, and flagellar type III secretion system (fT3SS) core proteins that form a competent fT3SS. Conserved regulatory mechanisms in diverse polar flagellates to create this polar flagellar transcriptional program have not been thoroughly assimilated. Using in silico and genetic analyses and our previous findings in Campylobacter jejuni as a foundation, we observed a large subset of Gram-negative bacteria with the FlhF/FlhG regulatory system for polar flagellation to possess flagellum-associated two-component signal transduction systems (TCSs). We present data supporting a general theme in polar flagellates whereby MS ring, rotor, and fT3SS proteins contribute to a regulatory checkpoint during polar flagellar biogenesis. We demonstrate that Vibrio cholerae and Pseudomonas aeruginosa require the formation of this regulatory checkpoint for the TCSs to directly activate subsequent rod and hook gene transcription, which are hallmarks of the polar flagellar transcriptional program. By reprogramming transcription in V. cholerae to more closely follow the peritrichous flagellar transcriptional program, we discovered a link between the polar flagellar transcription program and the activity of FlhF/FlhG flagellar biogenesis regulators in which the transcriptional program allows polar flagellates to continue to produce flagella for motility when FlhF or FlhG activity may be altered. Our findings integrate flagellar transcriptional and biogenesis regulatory processes involved in polar flagellation in many species. IMPORTANCE Relative to peritrichous bacteria, polar flagellates possess regulatory systems that order flagellar gene transcription differently and produce flagella in specific numbers only at poles. How transcriptional and flagellar biogenesis regulatory systems are interlinked to promote the correct synthesis of polar flagella in diverse species has largely been unexplored. We found evidence for many Gram-negative polar flagellates encoding two-component signal transduction systems with activity linked to the formation of flagellar type III secretion systems to enable production of flagellar rod and hook proteins at a discrete, subsequent stage during flagellar assembly. This polar flagellar transcriptional program assists, in some manner, the FlhF/FlhG flagellar biogenesis regulatory system, which forms specific flagellation patterns in polar flagellates in maintaining flagellation and motility when activity of FlhF or FlhG might be altered. Our work provides insight into the multiple regulatory processes required for polar flagellation.

show abstract

A flagellum-specific chaperone facilitates assembly of the core type III export apparatus of the bacterial flagellum

Cited by 56 publications

References 59 publications

In situ imaging of the bacterial flagellar motor disassembly and assembly processes

In situ imaging of the bacterial flagellar motor disassembly and assembly processes

The structure of an injectisome export gate demonstrates conservation of architecture in the core export gate between flagellar and virulence type three secretion systems

A Polar Flagellar Transcriptional Program Mediated by Diverse Two-Component Signal Transduction Systems and Basal Flagellar Proteins Is Broadly Conserved in Polar Flagellates

Contact Info

Product

Resources

About