Helicobacter pylori East Asian type CagA hijacks more SHIP2 by its EPIYA-D motif to potentiate the oncogenicity
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View abstract on PubMed
Summary
This summary is machine-generated.East Asian CagA (CagA<sup>E</sup>) from Helicobacter pylori is more carcinogenic than Western CagA (CagA<sup>W</sup>) because CagA<sup>E</sup> binds more SHIP2 phosphatase, enhancing Akt signaling and cell invasion.
Area Of Science
- Microbiology
- Molecular Biology
- Oncology
Background
- <i>Helicobacter pylori</i> CagA protein is a key oncogenic factor.
- CagA exists as East Asian (CagA<sup>E</sup>) and Western (CagA<sup>W</sup>) types, with CagA<sup>E</sup> exhibiting higher carcinogenicity.
- SHIP2 phosphatase plays a role in cellular signaling pathways perturbed by CagA.
Purpose Of The Study
- To investigate the molecular mechanisms underlying the higher oncogenicity of CagA<sup>E</sup> compared to CagA<sup>W</sup>.
- To elucidate the role of SHIP2 in mediating the differential oncogenic potential of CagA subtypes.
- To identify specific structural features responsible for the enhanced interaction between CagA<sup>E</sup> and SHIP2.
Main Methods
- Co-Immunoprecipitation and Pull-down assays to assess protein binding.
- Immunofluorescence staining to visualize SHIP2 localization and activity.
- Surface Plasmon Resonance (SPR) analysis to determine binding affinity.
- Site-directed mutagenesis to investigate the role of specific amino acid residues.
Main Results
- CagA<sup>E</sup> binds significantly more SHIP2 than CagA<sup>W</sup>.
- CagA<sup>E</sup> recruits higher amounts of SHIP2 to the plasma membrane, leading to increased PI(3,4)P<sub>2</sub> production.
- This results in enhanced Akt signaling activation, promoting IL-8 secretion, cell migration, and invasion.
- SPR analysis revealed a higher affinity between CagA<sup>E</sup>'s EPIYA-D motif and SHIP2's SH2 domain, attributed to a key Phenylalanine residue.
Conclusions
- CagA<sup>E</sup>'s enhanced carcinogenicity is mediated by its stronger interaction with SHIP2 via the EPIYA-D motif.
- The Phenylalanine residue at position Y+5 in the EPIYA-D motif is crucial for this high-affinity binding.
- Targeting the CagA<sup>E</sup>-SHIP2 interaction could offer strategies to mitigate <i>H. pylori</i>-associated gastric cancer risk.
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