Protein Domain : Type III secretion system lipoprotein HrcJ/YscJ IPR003282

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 with the host. The protein subunits of the system are very similar to those of bacterial flagellar biosynthesis []. However, while the latter forms a ring structure to allow secretion of flagellin and is an integral part of the flagellum itself, type III subunits in the outer membrane translocate secreted proteins through a channel-like structure.One of the outer membrane protein subunit families, termed "K"here for nomenclature purposes, aids in the structural assembly of the invasion complex []. It is also described as a lipoprotein. Members of this family include the Salmonella PrgK and SsaJ genes, MxiJ from Shigella, YscJ from Yersinia, and from the plant enteropathogens NolT (Rhizobium) and HrcJ Erwinia). The flagellar M-ring protein FliF also shares a low level of similarity, presumably due to evolution of the type III secretion system from the flagellar biosynthetic pathway.
Short Name	T3SS_HrcJ/YscJ