Influence of EPIYA-repeat polymorphism on the phosphorylation-dependent biological activity of Helicobacter pylori
Masanori Naito1, Takeshi Yamazaki, Ryouhei Tsutsumi
1Division of Molecular Oncology, Institute for Genetic Medicine, Hokkaido University, Sapporo, Japan.
Gastroenterology
|April 19, 2006
Summary
Helicobacter pylori CagA's EPIYA-repeat variations significantly alter its virulence. Polymorphism in CagA's EPIYA sites influences its interaction with host proteins, impacting gastric cancer development.
Area of Science:
- Microbiology
- Molecular Biology
- Oncology
Background:
- Helicobacter pylori CagA protein is a key virulence factor in gastric adenocarcinoma.
- CagA phosphorylation occurs at EPIYA sites by Src family kinases (SFKs).
- EPIYA site number and order vary among clinical H. pylori isolates due to gene recombination.
Purpose of the Study:
- To investigate how EPIYA-repeat polymorphism in CagA affects its interaction with SHP-2 and Csk.
- To understand the influence of EPIYA site variations on CagA's deregulatory activity in gastric epithelial cells.
Main Methods:
- Expressed various EPIYA-repeat variants of CagA in AGS gastric epithelial cells.
- Determined CagA binding to SHP-2 and Csk using sequential immunoprecipitation and immunoblotting.
Main Results:
- Multiple EPIYA-C or EPIYA-D sites enhanced CagA binding and deregulation of SHP-2.
- CagA binding to Csk correlated with the number of EPIYA-A and EPIYA-B sites.
- Increased Csk binding by CagA led to stronger inhibition of Src-dependent phosphorylation and attenuated cell elongation.
Conclusions:
- EPIYA-repeat polymorphism in CagA significantly modulates its phosphorylation-dependent activity.
- Variations in CagA's EPIYA repeats influence its potency as a bacterial virulence factor in gastric carcinogenesis.
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