PMID:17768234

Citation	Pattis, I, Weiss, E, Laugks, R, Haas, R and Fischer, W (2007) The Helicobacter pylori CagF protein is a type IV secretion chaperone-like molecule that binds close to the C-terminal secretion signal of the CagA effector protein. Microbiology (Reading, Engl.) 153:2896-909
Abstract	Type IV secretion systems are common bacterial macromolecule transporters that have been adapted to various functions, such as effector protein translocation to eukaryotic cells, nucleoprotein transfer to bacterial or eukaryotic cells, and DNA transport into and out of bacterial cells. Helicobacter pylori, the causative agent of bacterial gastritis, peptic ulcers, gastric adenocarcinoma and mucosa-associated lymphoid tissue (MALT) lymphoma, uses the Cag type IV secretion system to inject the CagA protein into host cells, thereby altering gene expression profiles and the host cell cytoskeleton. The molecular mechanism of CagA recognition as a type IV substrate is only poorly understood, but seems to be more complex than that of other type IV secretion systems. Apart from 14 essential components of the secretion apparatus, CagA translocation specifically requires the presence of four additional Cag proteins. Here we show that the CagA-binding protein CagF is a secretion chaperone-like protein that interacts with a 100 aa region that is adjacent to the C-terminal secretion signal of CagA. The interaction between CagA and CagF takes place at the bacterial cytoplasmic membrane, and is independent of a functional type IV secretion apparatus and other cag-encoded factors. Our data indicate that CagF binding precedes recognition of the C-terminal CagA translocation signal, and that both steps are required to recruit CagA to the type IV translocation channel.
Links	PubMed Online version:10.1099/mic.0.2007/007385-0
Keywords	Antigens, Bacterial/chemistry; Antigens, Bacterial/genetics; Antigens, Bacterial/metabolism; Bacterial Proteins/chemistry; Bacterial Proteins/genetics; Bacterial Proteins/metabolism; Bacterial Proteins/secretion; Cell Membrane/metabolism; Gene Expression Regulation, Bacterial; Glutathione Transferase/genetics; Glutathione Transferase/metabolism; Helicobacter pylori/genetics; Helicobacter pylori/growth & development; Helicobacter pylori/pathogenicity; Humans; Molecular Chaperones/genetics; Molecular Chaperones/metabolism; Molecular Chaperones/secretion; Protein Sorting Signals/genetics; Protein Transport; Recombinant Fusion Proteins/genetics; Recombinant Fusion Proteins/metabolism
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
HELPX:P94835		GO:0042000: translocation of peptides or proteins into host	ECO:0000315:		P		Figure 1	complete CACAO 8754
HELPX:P94835	involved_in	GO:0042000: translocation of peptides or proteins into host	ECO:0000315: mutant phenotype evidence used in manual assertion		P		Seeded From UniProt	complete

References

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