DsbA directs efficient expression of outer membrane secretin EscC of the enteropathogenic Escherichia coli type III secretion apparatus.
The formation of disulfide bond is essential for the folding, activity, and stability of many secreted proteins of Gram-negative bacteria. The disulfide oxidoreductase, DsbA, introduces disulfide bonds into exported proteins from the cytoplasm. In pathogenic bacteria, DsbA is required to process virulence determinants for their folding and assembly. In this study, we investigated the role of DsbA in enteropathogenic Escherichia coli. Here, we show that the DsbA is required for stable expression of outer membrane secretin EscC. DsbA has no effect on LEE transcription as measured with LEE-lacZ fusions. Replacement of either cysteine residue 136 or 155 of EscC with a serine resulted in reduced level of EscC, similar to the effect of the dsbA mutation. These results demonstrate the role of DsbA in assembly of the type III secretion apparatus.
Miki
Tsuyoshi
T
Department of Microbiology, School of Pharmaceutical Sciences, Kitasato University, Tokyo, Japan.
Okada
Nobuhiko
N
Kim
Yeongsuk
Y
Abe
Akio
A
Danbara
Hirofumi
H
D000595:Amino Acid Sequence; D019943:Amino Acid Substitution / Q000235:genetics; D019677:Artificial Gene Fusion; D054308:Enteropathogenic Escherichia coli / Q000502:physiology*; D004847:Epithelial Cells / Q000382:microbiology; D029968:Escherichia coli Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D017353:Gene Deletion; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D017930:Genes, Reporter; D006367:HeLa Cells; D006461:Hemolysis; D006801:Humans; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D010750:Phosphoproteins / Q000096:biosynthesis; D019704:Protein Disulfide-Isomerases / Q000235:genetics / Q000378:metabolism*; D012633:Secretin / Q000096:biosynthesis* / Q000235:genetics; D001616:beta-Galactosidase / Q000096:biosynthesis / Q000235:genetics
D029968:Escherichia coli Proteins; C457340:LEE protein, E coli; D010750:Phosphoproteins; D012633:Secretin; D001616:beta-Galactosidase; D019704:Protein Disulfide-Isomerases; C526648:dsbA protein, E coli