Homologous Superfamily

Type III secretion system substrate exporter, C-terminal (IPR029025)

Short name: T3SS_substrate_exporter_C

Overlapping entries


Salmonella, and related proteobacteria, secrete large amounts of proteins into the culture media. The major secreted proteins are either flagellar proteins or virulence factors [PMID: 10564516], secreted through the flagellar or virulence export structures respectively. Both secretion systems penetrate the inner and outer membranes and their components bear substantial sequence similarity. Both the flagellar and needle like pilus look fairly similar to each other [PMID: 9554854].

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 [PMID: 10334981] and is only triggered when the bacterium comes into close contact with the host.

It is believed that the family of type III flagellar and pilus inner membrane proteins are used as structural moieties in a complex with several other subunits [PMID: 9618447]. One such set of inner membrane proteins, labeled "S" here for nomenclature purposes, includes the Salmonella and Shigella SpaS, the Yersinia YscU, Rhizobium Y4YO, and the Erwinia HrcU genes, Salmonella FlhB and Escherichia coli EscU [PMID: 9618447, PMID: 16246842, PMID: 8045883, PMID: 8169210].

This superfamily represent the C-terminal domain of the type III secretion system substrate exporters. Many of the proteins containing this domain undergo autocatalytic cleavage promoted by cyclisation of a conserved asparagine.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.