Protein Domain : Type III secretion system inner membrane R protein IPR002010

Type	Family
Description	Secretion of virulence factors in Gram-negative bacteria involves transportation of the protein across two membranes to reach the cell exterior [ ]. 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 []. 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 [ ] and is only triggered when the bacterium comes into close contact withthe host. The protein subunits of the system are very similar to those of bacterial flagellar biosynthesis []. However, while the latter forms aring structure to allow secretion of flagellin and is an integral part of the flagellum itself [], type III subunits in the outer membranetranslocate 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 []. 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 [ ]. The flagellar protein FliR also shares similarity, probably due to evolution of the type III secretion system from the flagellar biosynthetic pathway.
Short Name	T3SS_IM_R