SHP-2 Tyrosine Phosphatase as an Intracellular Target of Helicobacter pylori CagA Protein

Helicobacter pylori CagA protein is associated with severe gastritis and gastric carcinoma. CagA is injected from the attached Helicobacter pylori into host cells and undergoes tyrosine phosphorylation. Wild-type but not phosphorylation-resistant CagA induced a growth factor-like response in gastric epithelial cells. Furthermore, CagA formed a physical complex with the SRC homology 2 domain (SH2)-containing tyrosine phosphatase SHP-2 in a phosphorylation-dependent manner and stimulated the phosphatase activity. Disruption of the CagA-SHP-2 complex abolished the CagA-dependent cellular response. Conversely, the CagA effect on cells was reproduced by constitutively active SHP-2. Thus, upon translocation, CagA perturbs cellular functions by deregulating SHP-2.