Abstract:
:Despite the autotransporter (AT) moniker, AT secretion appears to involve the function of periplasmic chaperones. We identified four periplasmic proteins that specifically bound to plasmid-encoded toxin (Pet), an AT produced by enteroaggregative Escherichia coli (EAEC). These proteins include the 17-kDa Skp chaperone and the 37-kDa VirK protein. We found that the virK gene is present in different Enterobacteriaceae. VirK bound to misfolded conformations of the Pet passenger domain, but it did not bind to the folded passenger domain or to the β domain of Pet. Assays with an EAECΔvirK mutant and its complemented version showed that, in the absence of VirK, Pet was not secreted but was instead retained in the periplasm as proteolytic fragments. In contrast, Pet was secreted from a Δskp mutant. VirK was not required for the insertion of porin proteins into the outer membrane but assisted with insertion of the Pet β domain into the outer membrane. Loss of VirK function blocked the EAEC-mediated cytotoxic effect against HEp-2 cells. Thus, VirK facilitates the secretion of the AT Pet by maintaining the passenger domain in a conformation that both avoids periplasmic proteolysis and facilitates β-domain insertion into the outer membrane.
journal_name
Infect Immunjournal_title
Infection and immunityauthors
Tapia-Pastrana G,Chavez-Dueñas L,Lanz-Mendoza H,Teter K,Navarro-García Fdoi
10.1128/IAI.00167-12subject
Has Abstractpub_date
2012-07-01 00:00:00pages
2276-85issue
7eissn
0019-9567issn
1098-5522pii
IAI.00167-12journal_volume
80pub_type
杂志文章abstract::Normal bacteria can translocate (migrate) across an intact intestinal mucosa, but the anatomical site of bacterial translocation has not been defined. Gastrointestinal (GI) cross-sections were obtained from mice monoassociated with high cecal concentrations of Escherichia coli, Proteus mirabilis, or Enterococcus faeca...
journal_title:Infection and immunity
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journal_title:Infection and immunity
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journal_title:Infection and immunity
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journal_title:Infection and immunity
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journal_title:Infection and immunity
pub_type: 杂志文章
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doi:10.1128/IAI.62.2.673-679.1994
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更新日期:1997-05-01 00:00:00
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journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.38.1.21-26.1982
更新日期:1982-10-01 00:00:00
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更新日期:1983-04-01 00:00:00
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journal_title:Infection and immunity
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journal_title:Infection and immunity
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