MxiJ, a lipoprotein involved in secretion of Shigella Ipa invasins, is homologous to YscJ, a secretion factor of the Yersinia Yop proteins.
Shigella flexneri causes bacillary dysentery by invading epithelial cells of the colonic mucosa. The invasion process requires the synthesis and secretion of the virulence plasmid-encoded Ipa proteins. Using TnphoA mutagenesis, we have identified two virulence plasmid genes, mxiJ and mxiM, that encode proteins exported by the general export pathway. Analysis of the MxiJ and MxiM deduced amino acid sequences suggested that mxiJ and mxiM might encode lipoproteins, which was confirmed by [3H]palmitate labeling of MxiJ:PhoA and MxiM:PhoA fusion proteins. A mxiJ mutant was unable to invade HeLa cells, to induce the formation of plaques on confluent monolayers of HeLa cells, and to provoke keratoconjunctivitis in guinea pigs. In addition, secretion of seven polypeptides, including IpaA, IpaB, and IpaC, was abolished in the mxiJ mutant. Sequence comparisons indicated that MxiJ and MxiH, which is encoded by a gene located upstream from mxiJ, are homologous to the Yersinia enterocolitica YscJ and YscF proteins, respectively.
Allaoui
A
A
Unité de Pathogénie Microbienne Moléculaire, Unité INSERM 199, Institut Pasteur, Paris, France.
Sansonetti
P J
PJ
Parsot
C
C
D018829:Adhesins, Bacterial; D000818:Animals; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins / Q000235:genetics*; D001483:Base Sequence; D004251:DNA Transposable Elements; D004926:Escherichia coli / Q000235:genetics; D005798:Genes, Bacterial / Q000235:genetics*; D006168:Guinea Pigs; D006367:HeLa Cells; D006801:Humans; D008074:Lipoproteins / Q000235:genetics* / Q000378:metabolism*; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D019308:Palmitic Acid; D010169:Palmitic Acids / Q000378:metabolism; D010957:Plasmids / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D012763:Shigella flexneri / Q000235:genetics* / Q000472:pathogenicity*; D014774:Virulence
D018829:Adhesins, Bacterial; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D004251:DNA Transposable Elements; D008074:Lipoproteins; C413572:MxiH protein, Shigella; D010169:Palmitic Acids; C053476:invasin, Yersinia; C078386:YscJ protein, Yersinia enterocolitica; C078385:mxiJ protein, Shigella flexneri; C078384:mxiM protein, Shigella flexneri; D019308:Palmitic Acid