ESAT-6-Like Protein Secretion in Bacillus anthracis
- 1 November 2008
- journal article
- Published by American Society for Microbiology in Journal of Bacteriology
- Vol. 190 (21), 7004-7011
- https://doi.org/10.1128/jb.00458-08
Abstract
Proteins of the WXG100 family represent the prototypical substrates of bacterial type VII secretion systems that typically encompass 100 residues, lack canonical signal peptides, and form helix-turn-helix hairpin structures with WXG positioned in the turn element. Bacillus anthracis encodes six WXG100 proteins, herein referred to as EsxB, EsxL, EsxP, EsxQ, EsxV, and EsxW. With the exception of EsxB, B. anthracis proteins harbor C-terminal extensions that are appended to canonical WXG domains. When cultured in liquid broth, B. anthracis secretes two substrates, EsxB and EsxW, into the extracellular environment. EsxB is required for the stability and secretion of EsxW; however, EsxW is dispensable for EsxB secretion. In agreement with the hypothesis that EsxB binding to substrates promotes recognition and secretion by the type VII pathway, EsxB is reported to interact with EsxB and EsxW. Unlike deletions in mycobacterial EsxB, deletion of five N- or C-terminal residues does not affect the ability of mutant B. anthracis EsxB to travel the type VII pathway and initiate secretion of EsxW. Translational fusion of ubiquitin to the N or C terminus of EsxB also had no effect, while ubiquitin insertion into the center turn abrogated secretion. Anthrax-infected guinea pigs mounted humoral immune responses to EsxB, EsxP, and EsxW, which suggests that B. anthracis activates the type VII secretion pathway during infection.Keywords
This publication has 31 references indexed in Scilit:
- EsaC substrate for the ESAT‐6 secretion pathway and its role in persistent infections of Staphylococcus aureusMolecular Microbiology, 2008
- A Mycobacterium ESX-1–Secreted Virulence Factor with Unique Requirements for ExportPLoS Pathogens, 2007
- A specific secretion system mediates PPE41 transport in pathogenic mycobacteriaMolecular Microbiology, 2006
- C-Terminal Signal Sequence Promotes Virulence Factor Secretion in Mycobacterium tuberculosisScience, 2006
- Structure and function of the complex formed by the tuberculosis virulence factors CFP-10 and ESAT-6The EMBO Journal, 2005
- Recombinant BCG exporting ESAT-6 confers enhanced protection against tuberculosisNature Medicine, 2003
- Conclusive Evidence That the Major T-cell Antigens of theMycobacterium tuberculosis Complex ESAT-6 and CFP-10 Form a Tight, 1:1 Complex and Characterization of the Structural Properties of ESAT-6, CFP-10, and the ESAT-6·CFP-10 ComplexJournal of Biological Chemistry, 2002
- AnthraxAnnual Review of Microbiology, 2001
- A Mycobacterium tuberculosis operon encoding ESAT=6 and a novel low-molecular-mass culture filtrate protein (CFP-10)Microbiology, 1998
- In Vivo Half-Life of a Protein Is a Function of Its Amino-Terminal ResidueScience, 1986