Identification and characterization of NleA, a non-LEE-encoded type III translocated virulence factor of enterohaemorrhagic Escherichia coli O157:H7.
Enterohaemorrhagic Escherichia coli (EHEC) O157:H7 uses a specialized protein translocation apparatus, the type III secretion system (TTSS), to deliver bacterial effector proteins into host cells. These effectors interfere with host cytoskeletal pathways and signalling cascades to facilitate bacterial survival and replication and promote disease. The genes encoding the TTSS and all known type III secreted effectors in EHEC are localized in a single pathogenicity island on the bacterial chromosome known as the locus for enterocyte effacement (LEE). In this study, we performed a proteomic analysis of proteins secreted by the LEE-encoded TTSS of EHEC. In addition to known LEE-encoded type III secreted proteins, such as EspA, EspB and Tir, a novel protein, NleA (non-LEE-encoded effector A), was identified. NleA is encoded in a prophage-associated pathogenicity island within the EHEC genome, distinct from the LEE. The LEE-encoded TTSS directs translocation of NleA into host cells, where it localizes to the Golgi apparatus. In a panel of strains examined by Southern blot and database analyses, nleA was found to be present in all other LEE-containing pathogens examined, including enteropathogenic E. coli and Citrobacter rodentium, and was absent from non-pathogenic strains of E. coli and non-LEE-containing pathogens. NleA was determined to play a key role in virulence of C. rodentium in a mouse infection model.
Biotechnology Laboratory, University of British Columbia, Room 237, Wesbrook Building, 6174 University Boulevard, Vancouver, BC, V6T 1Z3, Canada.
Samantha
S
Gruenheid
Inna
I
Sekirov
Nikhil A
NA
Thomas
Wanyin
W
Deng
Paul
P
O'Donnell
David
D
Goode
Yuling
Y
Li
Elizabeth A
EA
Frey
Nathaniel F
NF
Brown
Pavel
P
Metalnikov
Tony
T
Pawson
Keith
K
Ashman
B Brett
BB
Finlay
D000595:Amino Acid Sequence; D000818:Animals; D002954:Citrobacter / Q000235:genetics / Q000378:metabolism / Q000472:pathogenicity; D003106:Colon / Q000166:cytology / Q000382:microbiology / Q000473:pathology; D004756:Enterobacteriaceae Infections / Q000382:microbiology; D019453:Escherichia coli O157 / Q000235:genetics / Q000378:metabolism* / Q000472:pathogenicity; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D016680:Genome, Bacterial; D044404:Genomic Islands; D006056:Golgi Apparatus / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D051379:Mice; D008815:Mice, Inbred Strains; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D021381:Protein Transport; D020543:Proteome / Q000032:analysis; D016415:Sequence Alignment; D013154:Spleen / Q000166:cytology / Q000382:microbiology / Q000473:pathology; D037521:Virulence Factors / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*
D029968:Escherichia coli Proteins; C488216:NleA protein, E coli; D020543:Proteome; D037521:Virulence Factors