F
IPR008514

Type VI secretion system effector Hcp

InterPro entry
Short nameT6SS_Hcp
Overlapping
homologous
superfamilies
 

Description

This entry consists of Hcp-like proteins. Hcp appears to be part of the type VI secretion system of Gram-negative bacteria. Hcp is not only a secreted effector protein, but also might act as machine component
[3]
.

Several bacterial pathogens mediate interactions with their hosts through protein secretion, often involving Hcp-like virulence loci, which are widely distributed among pathogenic bacteria. Homologues of Hcp are found in various bacteria of which most, but not all, are known pathogens. Many bacteria have two copies of hcp genes
[4, 5]
. In Pseudomonas syringae, Hcp1 is a virulence protein, while Hcp2 seems to be required for survival in competition with enterobacteria and yeasts, and its function is associated with the suppression of the growth of these competitors
[2]
.

Hcp1 monomers form a hexameric ring with a large internal diameter. Assembly of this particle is likely to occur following secretion, and could have a role in building a channel for the transport of other macromolecules
[1]
.

The type VI secretion system (T6SS) is a supra-molecular bacterial complex that resembles phage tails. It is a toxin delivery systems which fires toxins into target cells upon contraction of its TssBC sheath
[7]
. Thirteen essential core proteins are conserved in all T6SSs: the membrane associated complex TssJ-TssL-TssM, the baseplate proteins TssE, TssF, TssG, and TssK, the bacteriophage-related puncturing complex composed of the tube (Hcp), the tip/puncturing device VgrG, and the contractile sheath structure (TssB and TssC). Finally, the starfish-shaped dodecameric protein, TssA, limits contractile sheath polymerization at its distal part when TagA captures TssA
[6]
.

References

1.A virulence locus of Pseudomonas aeruginosa encodes a protein secretion apparatus. Mougous JD, Cuff ME, Raunser S, Shen A, Zhou M, Gifford CA, Goodman AL, Joachimiak G, Ordonez CL, Lory S, Walz T, Joachimiak A, Mekalanos JJ. Science 312, 1526-30, (2006). View articlePMID: 16763151

2.Hcp2, a secreted protein of the phytopathogen Pseudomonas syringae pv. tomato DC3000, is required for fitness for competition against bacteria and yeasts. Haapalainen M, Mosorin H, Dorati F, Wu RF, Roine E, Taira S, Nissinen R, Mattinen L, Jackson R, Pirhonen M, Lin NC. J. Bacteriol. 194, 4810-22, (2012). View articlePMID: 22753062

3.The type VI secretion toolkit. Cascales E. EMBO Rep. 9, 735-41, (2008). View articlePMID: 18617888

4.Hcp family proteins secreted via the type VI secretion system coordinately regulate Escherichia coli K1 interaction with human brain microvascular endothelial cells. Zhou Y, Tao J, Yu H, Ni J, Zeng L, Teng Q, Kim KS, Zhao GP, Guo X, Yao Y. Infect. Immun. 80, 1243-51, (2012). View articlePMID: 22184413

5.Evaluation of the roles played by Hcp and VgrG type 6 secretion system effectors in Aeromonas hydrophila SSU pathogenesis. Sha J, Rosenzweig JA, Kozlova EV, Wang S, Erova TE, Kirtley ML, van Lier CJ, Chopra AK. Microbiology (Reading, Engl.) 159, 1120-35, (2013). View articlePMID: 23519162

6.Baseplate Component TssK and Spatio-Temporal Assembly of T6SS in Pseudomonas aeruginosa. Liebl D, Robert-Genthon M, Job V, Cogoni V, Attree I. Front Microbiol 10, 1615, (2019). PMID: 31379775

7.TssA forms a gp6-like ring attached to the type VI secretion sheath. Planamente S, Salih O, Manoli E, Albesa-Jove D, Freemont PS, Filloux A. EMBO J. 35, 1613-27, (2016). PMID: 27288401

Cross References

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