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Recognition of the WXG Substrate YukE by the Type VII Secretion System in Bacillus subtilis
Author(s) -
Sysoeva Tatyana A,
Huppert Laura A,
Ramsdell Talia L,
Fortune Sarah M,
Burton Briana M
Publication year - 2013
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.27.1_supplement.554.6
Subject(s) - bacillus subtilis , secretion , operon , virulence , biology , secretory protein , proteolysis , biochemistry , microbiology and biotechnology , bacteria , escherichia coli , gene , genetics , enzyme
Type VII protein secretion systems are crucial for the virulence of several human pathogens such as Mycobacterium tuberculosis and Staphylococcus aureus. However, the mechanism of secretion and the function of the secreted substrates are poorly understood. Type VII secretion systems were predicted to exist in numerous non‐pathogenic Gram‐positive organisms including Bacillus subtilis . It was recently demonstrated that the B. subtilis yuk operon encodes a functional Type VII secretion system that exports the small virulence factor homolog YukE. Each of the proteins encoded by the yuk operon is essential for YukE transport. Our study reveals that YukE undergoes unspecific, post‐secretion proteolysis. To address the substrate requirements for secretion and explore the role of the processing, we conducted mutational analysis of the YukE protein that belongs to the WXG protein family. The results show that conserved tryptophan and glycine residues are crucial for the recognition of this substrate by the secretory machinery. Intact C‐terminal residues are also important for efficient secretion of this WXG protein. These data reveal that recognition of the substrate in Yuk‐system in B. subtilis is similar to that of other Type VII secretion systems. These experiments open the possibility of using B. subtilis as a platform to investigate the core interactions between substrate and this novel secretion apparatus.