AKT1 and infection: We then examined the potential activation of PI3K/Akt and MEK/ERK pathways after the infection of MG6 cells and primary cultured microglia with P. gingivalis. Akt is a serine/threonine protein kinase activated by stimuli that induce the production of phosphatidylinositol (3,4,5)-trisphosphate through activation of PI3K27.