title: The aggregation domain of aggregation substance, not the RGD motifs, is critical for efficient internalization by HT-29 enterocytes.
abstract: Aggregation substance (AS), a surface protein encoded on the pheromone-inducible plasmids of Enterococcus faecalis, has been shown to increase adherence and internalization into a number of different cell types, presumably through integrin binding mediated by the N-terminal RGD motif of AS. Here, defined mutations constructed in Asc10, the AS encoded by the plasmid pCF10, are analyzed for their ability to promote increased internalization levels into HT-29 enterocytes. The results clearly show that the previously identified Asc10 functional domain, not the RGD motifs, is critical for Asc10-directed internalization of E. faecalis into HT-29 enterocytes. Also, expression of Asc10 in the nonaggregating E. faecalis strain INY3000 is unable to mediate HT-29 internalization. However, Asc10-expressing E. faecalis cells are not internalized as bacterial aggregates, suggesting bacterial aggregation is not a prerequisite for HT-29 internalization. These data show that Asc10 directs internalization of E. faecalis into HT-29 enterocytes through a non-RGD-dependent mechanism.
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000502:physiology*; D001483:Base Sequence; D002460:Cell Line; D004269:DNA, Bacterial / Q000235:genetics; D013293:Enterococcus faecalis / Q000235:genetics / Q000472:pathogenicity* / Q000502:physiology; D020895:Enterocytes / Q000382:microbiology; D016908:Gram-Positive Bacterial Infections / Q000209:etiology; D006801:Humans; D008565:Membrane Proteins / Q000737:chemistry* / Q000235:genetics / Q000502:physiology*; D009154:Mutation; D009842:Oligopeptides / Q000737:chemistry; D017434:Protein Structure, Tertiary; D014774:Virulence
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D008565:Membrane Proteins; D009842:Oligopeptides; C065937:aggregation substance, Enterococcus faecalis; C071729:Asc10 protein, Enterococcus faecalis; C047981:arginyl-glycyl-aspartic acid