PR01302

TYPE3IMPPROT

PRINTS entry
Member databasePRINTS
PRINTS typefamily
Short nameTYPE3IMPPROT

Description
Imported from IPR005838

Secretion of virulence factors in Gram-negative bacteria involves transportation of the protein across two membranes to reach the cell exterior
[1]
. 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
[2]
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
[3]
. However, while the latter forms a ring structure to allow secretion of flagellin and is an integral part of the flagellum itself
[3]
, 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
[4]
, including the ATPase necessary for driving the secretion system.

One such set of inner membrane proteins, termed "P" here for nomenclature purposes, includes the Salmonella and Shigella SpaP, the Yersinia YscR, the Erwinia HrcR, and the Xanthamonas Pro2 genes
[4]
, as well as several FliP flagellar biosynthesis genes
[3]
. FliP is an ~30Kd protein containing three or four transmembrane (TM) regions.

References
Imported from IPR005838

1.Molecular mechanisms of bacterial virulence: type III secretion and pathogenicity islands. Mecsas JJ, Strauss EJ. Emerging Infect. Dis. 2, 270-88, (1996). PMID: 8969244

2.Type III secretion machines: bacterial devices for protein delivery into host cells. Galan JE, Collmer A. Science 284, 1322-8, (1999). View articlePMID: 10334981

3.Flagellar proteins and type III-exported virulence factors are the predominant proteins secreted into the culture media of Salmonella typhimurium. Komoriya K, Shibano N, Higano T, Azuma N, Yamaguchi S, Aizawa SI. Mol. Microbiol. 34, 767-79, (1999). View articlePMID: 10564516

4.Type III protein secretion systems in bacterial pathogens of animals and plants. Hueck CJ. Microbiol. Mol. Biol. Rev. 62, 379-433, (1998). View articlePMID: 9618447

Supplementary References

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