English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Specialized secretion systems of pathogenic bacteria commonly transport multiple effectors that act in concert to control and exploit the host cell as a replication-permissive niche. Both the  Mycobacterium marinum  and the  Mycobacterium tuberculosis  genomes contain an extended region of difference 1 (extRD1) locus that encodes one such pathway, the early secretory antigenic target 6 (ESAT-6) system 1 (ESX-1) secretion apparatus. ESX-1 is required for virulence and for secretion of the proteins ESAT-6, culture filtrate protein 10 (CFP-10), and EspA. Here, we show that both Rv3881c and its  M. marinum  homolog, Mh3881c, are secreted proteins, and disruption of RD1 in either organism blocks secretion. We have renamed the  Rv3881c/Mh3881c  gene  espB  for ESX-1 substrate protein B. Secretion of  M. marinum  EspB (EspB M ) requires both the  Mh3879c  and  Mh3871  genes within RD1, while CFP-10 secretion is not affected by disruption of  Mh3879c . In contrast, disruption of  Mh3866  or  Mh3867  within the extRD1 locus prevents CFP-10 secretion without effect on EspB M . Mutants that fail to secrete only EspB M  or only CFP-10 are less attenuated in macrophages than mutants failing to secrete both substrates. EspB M  physically interacts with Mh3879c; the  M. tuberculosis  homolog, EspB T , physically interacts with Rv3879c; and mutants of EspB M  that fail to bind Mh3879c fail to be secreted. We also found interaction between Rv3879c and Rv3871, a component of the ESX-1 machine, suggesting a mechanism for the secretion of EspB. The results establish EspB as a substrate of ESX-1 that is required for virulence and growth in macrophages and suggests that the contribution of ESX-1 to virulence may arise from the secretion of multiple independent substrates.

A Mycobacterium ESX-1–Secreted Virulence Factor with Unique Requirements for Export