Effect of cellular level of fliK on flagellar hook and filament assembly in Salmonella typhimurium 1 1Edited by M. F. Moody

Muramoto, Kazumasa; Makishima, Shigeru; Aizawa, Shin‐Ichi; Macnab, Robert M.

doi:10.1006/jmbi.1998.1659

Cited by 55 publications

(86 citation statements)

References 29 publications

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“…Since this interaction induces the substrate specificity switch, the switch might occur earlier in strains that oversecrete FliK, thus leading to shorter hooks (162). In agreement with this model, overexpression of FliK was previously shown to result in shorter hooks (399). In conclusion, the experimental data published to date on mechanisms underlying flagellar hook length control support the infrequent molecular ruler model rather than the molecular cup or molecular clock model.…”

Section: T3s Substrate Specificity Switching In Flagellar T3s Systemssupporting

confidence: 72%

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

363

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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Section: T3s Substrate Specificity Switching In Flagellar T3s Systemssupporting

confidence: 72%

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

363

482

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“…This suggests that the FlgD (1-138f-s+4aa) cap cannot efficiently promote the assembly of newly exported FlgE monomers at the hook tip. In agreement with previous observations that wild-type cells overproducing FlgE produce longer hooks with a broader length distribution than the wild-type (Muramoto et al, 1999;Moriya et al, 2006), the SD of the length distribution was still much larger than the wild-type value (Fig. 5b).…”

Section: Multicopy Effect Of Flge On Motility Of the Flgd Mutantssupporting

confidence: 93%

Genetic analysis of the bacterial hook-capping protein FlgD responsible for hook assembly

et al. 2011

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FlgD of Salmonella enterica is a 232 aa protein that acts as the hook cap to promote assembly of FlgE into the hook structure. The N-terminal 86 residues (FlgD N ) complement flgD mutants, albeit to a small degree. However, little is known about the role of the C-terminal region of FlgD (FlgD C ). Here we isolated pseudorevertants from Salmonella flgE mutants. About half of the extragenic mutations lay within FlgD C and only one in FlgD N . These suppressor mutations prevented mutant FlgE subunits from leaking out to some degree. Two weakly motile flgD mutants encoding C-terminally truncated variants, FlgD and FlgD (1-138f-s+4aa) , secreted larger amounts of FlgE into the culture medium than wild-type cells. Their hooks were shorter, and their length distributions were broader, with significant tailing towards smaller values. These results suggest that FlgD C contributes to efficient hook polymerization. Therefore, we propose that FlgD N attaches to the distal end of the hook to promote hook polymerization and that FlgD C blocks the exit of newly exported FlgE monomers into the culture medium, allowing FlgE to have more time to assemble into the hook.

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“…However, the placements of spa32, invJ, fliK, and yscP in the respective operons were all similar, and each of the gene products was secreted (6,32,36,40,42; this study). Furthermore, the production of each protein was required for a functional type III secretion system (Spa32, InvJ, and YscP) (7, 36, 42; this study) or flagellar export system (FliK) (20,33,48). Consequently, we wondered whether Spa32 and its putative cognates would share similar functions.…”

Section: Resultsmentioning

confidence: 95%

Shigella Spa32 Is an Essential Secretory Protein for Functional Type III Secretion Machinery and Uniformity of Its Needle Length

et al. 2002

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The Shigella type III secretion machinery is responsible for delivering to host cells the set of effectors required for invasion. The type III secretion complex comprises a needle composed of MxiH and MxiI and a basal body made up of MxiD, MxiG, and MxiJ. In S. flexneri, the needle length has a narrow range, with a mean of approximately 45 nm, suggesting that it is strictly regulated. Here we show that Spa32, encoded by one of the spa genes, is an essential protein translocated via the type III secretion system and is involved in the control of needle length as well as type III secretion activity. When the spa32 gene was mutated, the type III secretion complexes possessed needles of various lengths, ranging from 40 to 1,150 nm. Upon introduction of a cloned spa32 into the spa32 mutant, the bacteria produced needles of wild-type length. The spa32 mutant overexpressing MxiH produced extremely long (>5 m) needles. Spa32 was secreted into the medium via the type III secretion system, but secretion did not depend on activation of the system. The spa32 mutant and the mutant overexpressing MxiH did not secrete effectors such as Ipa proteins into the medium or invade HeLa cells. Upon introduction of Salmonella invJ, encoding InvJ, which has 15.4% amino acid identity with Spa32, into the spa32 mutant, the bacteria produced type III needles of wild-type length and efficiently entered HeLa cells. These findings suggest that Spa32 is an essential secreted protein for a functional type III secretion system in Shigella spp. and is involved in the control of needle length. Furthermore, its function is interchangeable with that of Salmonella InvJ.The type III protein secretion system is found among various gram-negative animal-and plant-pathogenic bacteria, in which the subsets of effector proteins that are secreted via the system into host cells have crucial roles in the bacterial infection process (8,9,16,38). Genetic and functional studies indicate that the type III secretion system requires proteins encoded by more than 20 genes, which contain the structural components of the secretion complex, secreted proteins, chaperones, and regulators (10,11,19,37,43). In Shigella spp., the system is encoded by approximately 20 genes located in the mxi and spa operons on a large 230-kb plasmid (5, 19). The proteins of the type III secretion system show considerable amino acid homology among different pathogens, and some of them also show amino acid homology with the components of the bacterial flagellar export system (26). Although the function of the type III secretion system in bacterial infection is distinct from that of the flagellar export system, the type III secretion system is believed to have evolved from the flagellar export system and diverged in each pathogen to become involved in the infection process (15).Recent studies indicate that the type III secretion complexes of Shigella flexneri and Salmonella spp. share structural similarities; the complexes are composed of two distinct parts, a basal body and a needle. The basal...

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Effect of cellular level of fliK on flagellar hook and filament assembly in Salmonella typhimurium 1 1Edited by M. F. Moody

Cited by 55 publications

References 29 publications

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

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

Genetic analysis of the bacterial hook-capping protein FlgD responsible for hook assembly

Shigella Spa32 Is an Essential Secretory Protein for Functional Type III Secretion Machinery and Uniformity of Its Needle Length

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