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The Haemolysin secretion/activation protein (ShlB/FhaC/HecB) Family [Function: Biogenesis/Secretion] Seed alignment | Full alignment | Pfam page | TC-DB page

The type V secretion pathway encompasses the autotransporter proteins (AT), the two-partner secretion system (TPS) and the type AT-2 family of proteins. TPS systems are composed of two separate proteins, with TpsA being the secreted protein and TpsB its specific transporter. The secreted proteins are exported in a Sec-dependent manner across the inner membrane, after which they cross the outer membrane with the help of their cognate transporters. Translocation appears to be folding-sensitive, indicating that TpsA proteins cross the periplasm and the outer membrane in non-native conformations and fold progressively at the cell surface. A major difference of the TPS pathways compared to the AT arises from the manner in which specificity is established between the secreted protein and its transporter. The TPS pathway has solved the question of specific recognition between the TpsA proteins and their transporters by the addition to the TpsA proteins of an N-proximal module, the conserved TPS domain, which represents a hallmark of the TPS pathway. The exoproteins of the TPS have been reported to be adhesins, haem-binding proteins, antigenic factors or haemolysins/cytolysins. The structure of the TPS domain has been solved and shows to fold as a ß helix. The crystal structure of the transmembrane domain of the Bordetella pertussis TpsB transporter (FhaC) has been resolved revealling a ß-barrel with 16 transmembrane strands.


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Literature references


Bordetella Filamentous Hemagglutinin, a Model for the Two-Partner Secretion Pathway
Microbiol Spectr. 2019 Mar;7(2):10.1128/microbiolspec.PSIB-0024-2018. doi: 10.1128/microbiolspec.PSIB-0024-2018.
PMID: 30927348

Sequential unfolding of the hemolysin two-partner secretion domain from Proteus mirabilis
Protein Sci. 2015 Nov;24(11):1841-55. doi: 10.1002/pro.2791. Epub 2015 Sep 9.
PMID: 26350294

Conserved Omp85 lid-lock structure and substrate recognition in FhaC
Nat Commun. 2015 Jun 10;6:7452. doi: 10.1038/ncomms8452.
PMID: 26058369

Structure-function analysis reveals that the Pseudomonas aeruginosa Tps4 two-partner secretion system is involved in CupB5 translocation
Protein Sci. 2015 May;24(5):670-87. doi: 10.1002/pro.2640. Epub 2015 Feb 24.
PMID: 25641651

An In Vitro Assay for Substrate Translocation by FhaC in Liposomes
Methods Mol Biol. 2015;1329:111-25. doi: 10.1007/978-1-4939-2871-2_8.
PMID: 26427679

Production and crystallization of bacterial type V secretion proteins
Methods Mol Biol. 2013;966:205-22. doi: 10.1007/978-1-62703-245-2_13.
PMID: 23299737

Two-partner secretion of gram-negative bacteria: a single ß-barrel protein enables transport across the outer membrane
J Biol Chem. 2012 Jan 20;287(4):2591-9. doi: 10.1074/jbc.M111.293068. Epub 2011 Dec 1.
PMID: 22134917

Functional importance of a conserved sequence motif in FhaC, a prototypic member of the TpsB/Omp85 superfamily
FEBS J. 2010 Nov;277(22):4755-65. doi: 10.1111/j.1742-4658.2010.07881.x. Epub 2010 Oct 19.
PMID: 20955520

Structure of the membrane protein FhaC: a member of the Omp85-TpsB transporter superfamily
Science. 2007 Aug 17;317(5840):957-61. doi: 10.1126/science.1143860.
PMID: 17702945

Protein secretion through autotransporter and two-partner pathways
Biochim Biophys Acta. 2004 Nov 11;1694(1-3):235-57. doi: 10.1016/j.bbamcr.2004.03.008.
PMID: 15546669

The autotransporter secretion system
Res Microbiol. 2004 Mar;155(2):53-60. doi: 10.1016/j.resmic.2003.10.002.
PMID: 14990256

Autotransporter and two-partner secretion: delivery of large-size virulence factors by gram-negative bacterial pathogens
Crit Rev Microbiol. 2004;30(4):275-86. doi: 10.1080/10408410490499872.
PMID: 15646401

Proteins in this family with 3D-structure
View Entry
Description
Organism
Length
# strands
Bacteriophage adsorption protein A
Bordetella pertussis (strain Tohama I / ATCC BAA-589 / NCTC 13251)
584
16
Outer membrane transporter CdiB
Escherichia coli
588
16


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