ATP-induced FliI hexamerization facilitates bacterial flagellar protein export

Kazetani, Ken-ichi; Minamino, Tetsuo; Miyata, Tomoko; Kato, Takayuki; Namba, Keiichi

doi:10.1016/j.bbrc.2009.08.004

Cited by 36 publications

(42 citation statements)

References 24 publications

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“…3C). In this regard, it is known that oligomerization of T3SS ATPases is required for maximum activity (72)(73)(74). The enzymatic activity of EscN showed positive cooperativity, indicating that oligomerization is coupled to an increase in ATP hydrolysis (33).…”

Section: Discussionmentioning

confidence: 99%

EscO, a Functional and Structural Analog of the Flagellar FliJ Protein, Is a Positive Regulator of EscN ATPase Activity of the Enteropathogenic Escherichia coli Injectisome

et al. 2014

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Type III secretion systems (T3SSs) are multiprotein molecular devices used by many Gram-negative bacterial pathogens to translocate effector proteins into eukaryotic cells. A T3SS is also used for protein export in flagellar assembly, which promotes bacterial motility. The two systems are evolutionarily related, possessing highly conserved components in their export apparatuses. Enteropathogenic Escherichia coli (EPEC) employs a T3SS, encoded by genes in the locus of enterocyte effacement (LEE) pathogenicity island, to colonize the human intestine and cause diarrheal disease. In the present work, we investigated the role of the LEE-encoded EscO protein (previously Orf15 or EscA) in T3SS biogenesis. We show that EscO shares similar properties with the flagellar FliJ and the Yersinia YscO protein families. Our findings demonstrate that EscO is essential for secretion of all categories of T3SS substrates. Consistent with its central role in protein secretion, it was found to interact with the ATPase EscN and its negative regulator, EscL, of the export apparatus. Moreover, we show that EscO stimulates EscN enzymatic activity; however, it is unable to upregulate ATP hydrolysis in the presence of EscL. Remarkably, EscO partially restored the swimming defect of a Salmonella flagellar fliJ mutant and was able to stimulate the ATPase activity of FliI. Overall, our data indicate that EscO is the virulence counterpart of the flagellar FliJ protein.

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Section: Discussionmentioning

confidence: 99%

EscO, a Functional and Structural Analog of the Flagellar FliJ Protein, Is a Positive Regulator of EscN ATPase Activity of the Enteropathogenic Escherichia coli Injectisome

et al. 2014

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“…The export apparatus of flagellar and translocation-associated T3S systems is associated with a cytoplasmic ATPase which is a member of the YscN protein family (YscN/InvC/Spa47/EscN) and forms homo-or double-hexameric ring structures with an internal diameter of approximately 2.5 to 3 nm (96,235,267,397,445). Oligomerization and membrane contact of YscN family members lead to an increase of the ATPase activity, which is predicted to provide the energy needed for the secretion process (18,21,96,378,445,627).…”

Section: Power Supplies-the Cytoplasmic Atpase and The Flagellar Motormentioning

confidence: 99%

Protein Export According to Schedule: Architecture, Assembly, and Regulation of Type III Secretion Systems from Plant- and Animal-Pathogenic Bacteria

Büttner

2012

Microbiol Mol Biol Rev

359

482

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SUMMARY Flagellar and translocation-associated type III secretion (T3S) systems are present in most Gram-negative plant- and animal-pathogenic bacteria and are often essential for bacterial motility or pathogenicity. The architectures of the complex membrane-spanning secretion apparatuses of both systems are similar, but they are associated with different extracellular appendages, including the flagellar hook and filament or the needle/pilus structures of translocation-associated T3S systems. The needle/pilus is connected to a bacterial translocon that is inserted into the host plasma membrane and mediates the transkingdom transport of bacterial effector proteins into eukaryotic cells. During the last 3 to 5 years, significant progress has been made in the characterization of membrane-associated core components and extracellular structures of T3S systems. Furthermore, transcriptional and posttranscriptional regulators that control T3S gene expression and substrate specificity have been described. Given the architecture of the T3S system, it is assumed that extracellular components of the secretion apparatus are secreted prior to effector proteins, suggesting that there is a hierarchy in T3S. The aim of this review is to summarize our current knowledge of T3S system components and associated control proteins from both plant- and animal-pathogenic bacteria.

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“…1). FliI (13), the only ATPase of the system, assembles to a hexameric ring (14,15) and is located at the base of the basal body (16). The exact role of FliI is not known, but it has been implicated in powering protein export, targeting flagellar proteins to the export gate, and functioning as a sorting platform or specificity switch (17).…”

mentioning

confidence: 99%

Recognition and targeting mechanisms by chaperones in flagellum assembly and operation

Khanra

Rossi

Economou

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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The flagellum is a complex bacterial nanomachine that requires the proper assembly of several different proteins for its function. Dedicated chaperones are central in preventing aggregation or undesired interactions of flagellar proteins, including their targeting to the export gate. FliT is a key flagellar chaperone that binds to several flagellar proteins in the cytoplasm, including its cognate filament-capping protein FliD. We have determined the solution structure of the FliT chaperone in the free state and in complex with FliD and the flagellar ATPase FliI. FliT adopts a four-helix bundle and uses a hydrophobic surface formed by the first three helices to recognize its substrate proteins. We show that the fourth helix constitutes the binding site for FlhA, a membrane protein at the export gate. In the absence of a substrate protein FliT adopts an autoinhibited structure wherein both the binding sites for substrates and FlhA are occluded. Substrate binding to FliT activates the complex for FlhA binding and thus targeting of the chaperone-substrate complex to the export gate. The activation and targeting mechanisms reported for FliT appear to be shared among the other flagellar chaperones.flagellum | chaperones | assembly factors | NMR spectroscopy | type III secretion

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ATP-induced FliI hexamerization facilitates bacterial flagellar protein export

Cited by 36 publications

References 24 publications

EscO, a Functional and Structural Analog of the Flagellar FliJ Protein, Is a Positive Regulator of EscN ATPase Activity of the Enteropathogenic Escherichia coli Injectisome

EscO, a Functional and Structural Analog of the Flagellar FliJ Protein, Is a Positive Regulator of EscN ATPase Activity of the Enteropathogenic Escherichia coli Injectisome

Protein Export According to Schedule: Architecture, Assembly, and Regulation of Type III Secretion Systems from Plant- and Animal-Pathogenic Bacteria

Recognition and targeting mechanisms by chaperones in flagellum assembly and operation

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