- EPIYA motifs are specific sequences of amino acids in the CagA protein of Helicobacter pylori.
- These motifs play a crucial role in the pathogenicity of the bacterium.
- The term “EPIYA” refers to the amino acid sequence Glutamic acid-Proline-Isoleucine-Tyrosine-Alanine.
- These motifs are located in the C-terminal region of the CagA protein and serve as phosphorylation sites when the protein is delivered into host cells.
- Once phosphorylated, EPIYA motifs interact with host cell signaling molecules, particularly SHP-2 (Src homology 2 domain-containing phosphatase). This interaction disrupts normal cellular signaling, promoting changes like uncontrolled cell growth or motility.
- The type and arrangement of EPIYA motifs influence the strength of CagA’s effects on host cells. For example, the East Asian EPIYA-D motif binds SHP-2 more strongly than the Western EPIYA-C motif.
- The EPIYA motifs are classified as EPIYA-A, EPIYA-B, EPIYA-C, and EPIYA-D based on their flanking sequences (the sequences of amino acids surrounding the core EPIYA segment) and location within the CagA protein.
- EPIYA-A and EPIYA-B are shared across both Western and East Asian types. EPIYA-C is characteristic of Western-type CagA. EPIYA-D is specific to East Asian-type CagA and has a higher oncogenic potential.
- These motifs are key to understanding the molecular mechanisms through which H. pylori contributes to diseases such as gastric cancer and peptic ulcers.
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