Overexpression of PI3K mutant protein ablates <i>L. pneumophila</i> entry.

<p>Entry by <i>L. pneumophila</i> into J774A.1 macrophages expressing the p85α mutant PI3K (pSR1NeoΔp85) and containing vector alone (pSR1Neo) after 1 hour co-incubation (A). Western analysis using antibody against the PI3K p85 α subunit, demonstrating Δp85 expression in transfected macrophages (B). Macrophage lysates were immunoprecipitated with anti-p85α and run on SDS/PAGE followed by Western blot analysis. Entry into macrophages carrying the vector alone was arbitrarily set to 100%. Data are the means+/−SEM for assays done in duplicate. Similar results were obtained in at least two independent experiments.