H. pylori activates Akt and induces p65 phosphorylation. (A) MKN45 or AGS cells were infected with H. pylori (ATCC 49503) for the indicated times. Cells were harvested, lysed and subjected to immunoblotting with the indicated antibodies. Akt in vitro kinase assay was performed after immunoprecipitation of Akt, with GSK-3 fusion protein serving as the exogenous substrate for Akt. Kinase reactions were analyzed by immunoblotting with monoclonal antibody for phospho-GSK-3 (serines 21 and 9). (B) The cag PAI of H. pylori is required for induction of Akt phosphorylation. MKN45 or AGS cells were infected with either the wild-type H. pylori strain 26695 (WT) or its isogenic cag PAI-lacking mutant strain (Δcag) for 1 h. Cells were harvested, lysed and subjected to immunoblotting with the indicated antibodies. Representative results of three similar experiments in each panel.