Fig. 1

Detection of short EPIYA-phosphopeptides from two H. pylori East Asian CagAs by α-phosphotyrosine antibodies. a East Asian CagA proteins of H. pylori, as shown here for the strains TN2-GF4 and Mand38, primarily carry the EPIYA-A, EPIYA-B and EPIYA-D segments (Table 1). These motifs can be phosphorylated by c-Abl and c-Src host kinases. b Various truncated EPIYA-A motif-derived phospho- and non-phosphopeptides from strain Mand38 were generated and analysed with the Dotblot method. These peptides were immobilized on PVDF membranes and probed with the indicated phosphotyrosine antibodies. On the right site, spot intensities derived from three independent experiments of the detected spots are quantified. The intensities of the signals were measured densitometrically by the Chemidoc imager and display the percentage of phosphorylation signal per sample. For every Dotblot the strongest spot was set to 100 % for each of the different α-phosphotyrosine antibodies as indicated. The resulting data indicate that 9-mer and 11-mer phosphopeptides are sufficient to reveal solid recognition by the antibodies. c Products of in vitro kinase reactions of c-Abl with bacterial lysates (from H. pylori wild-type strain TN2-GF4, Mand38 and isogenic ΔcagA mutant) were employed for control Dotblot experiments using antibodies α-PY-100 and α-PY20