Pas, a novel protein required for protein secretion and attaching and effacing activities of enterohemorrhagic Escherichia coli.
Enterohemorrhagic Escherichia coli (EHEC) exhibits a pattern of localized adherence to host cells, with the formation of microcolonies, and induces a specific histopathological phenotype collectively known as the attaching and effacing lesion. The genes encoding the products responsible for this phenotype are located on a 35-kb pathogenicity island designated the locus of enterocyte effacement, which is also shared by enteropathogenic E. coli. We have identified an open reading frame (ORF) which is located upstream of the espA, espB, and espD genes on the complementary strand and which exhibits high homology to the genes spiB from Salmonella, yscD from Yersinia, and pscD from Pseudomonas. Localization studies showed that the encoded product is present in the cytoplasmic and inner membrane fractions of EHEC. The construction and characterization of a recombinant clone containing an in-frame deletion of this ORF demonstrated that the encoded product is a putative member of a type III system required for protein secretion. Disruption of this ORF, designated pas (protein associated with secretion), abolished the secretion of Esp proteins. The mutant adhered only poorly and lost its capacities to trigger attaching and effacing activity and to invade HeLa cells. These results demonstrate that Pas is a virulence-associated factor that plays an essential role in EHEC pathogenesis.
Division of Microbiology, GBF-National Research Centre for Biotechnology, D-38124 Braunschweig, Germany.
A U
AU
Kresse
K
K
Schulze
C
C
Deibel
F
F
Ebel
M
M
Rohde
T
T
Chakraborty
C A
CA
Guzmán
D000199:Actins / Q000378:metabolism; D000595:Amino Acid Sequence; D001422:Bacterial Adhesion; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D003001:Cloning, Molecular; D004269:DNA, Bacterial; D019453:Escherichia coli O157 / Q000378:metabolism / Q000472:pathogenicity* / Q000502:physiology; D029968:Escherichia coli Proteins; D006367:HeLa Cells; D006801:Humans; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D011485:Protein Binding; D012486:Salmonella typhimurium / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D013347:Subcellular Fractions / Q000378:metabolism; D000069296:Type III Secretion Systems
D000199:Actins; D001426:Bacterial Proteins; D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; C114344:PAS protein, E coli; D000069296:Type III Secretion Systems