Bac_export_1

• PFAM accession number: PF01311
• Interpro abstract (IPR002010):

  Secretion of virulence factors in Gram-negative bacteria involves transportation of the protein across two membranes to reach the cell exterior [ (PUBMED:8969244) ]. There have been four secretion systems described in animal enteropathogens such as Salmonella and Yersinia, with further sequence similarities in plant pathogens like Ralstonia and Erwinia [ (PUBMED:8969244) ].

  The type III secretion system is of great interest, as it is used to transport virulence factors from the pathogen directly into the host cell [ (PUBMED:10334981) ] and is only triggered when the bacterium comes into close contact with the host. The protein subunits of the system are very similar to those of bacterial flagellar biosynthesis [ (PUBMED:10564516) ]. However, while the latter forms a ring structure to allow secretion of flagellin and is an integral part of the flagellum itself [ (PUBMED:10564516) ], type III subunits in the outer membrane translocate secreted proteins through a channel-like structure.

  It is believed that the family of type III inner membrane proteins are used as structural moieties in a complex with several other subunits [ (PUBMED:9618447) ]. One such set of inner membrane proteins, labeled "R" here for nomenclature purposes, includes the Salmonella and Shigella SpaR, the Yersinia YscT, Rhizobium Y4YN, and the Erwinia HrcT genes [ (PUBMED:9618447) ]. The flagellar protein FliR also shares similarity, probably due to evolution of the type III secretion system from the flagellar biosynthetic pathway.

• GO process: protein targeting (GO:0006605)
• GO component: membrane (GO:0016020)

This is a PFAM domain. For full annotation and more information, please see the PFAM entry Bac_export_1