The involvement of MAP/ERK and PI3K kinase pathways in regulation of IBV-induced Mcl-1 was first studied by infection of Vero and H1299 cells with IBV at an M.O.I. of 2 in the presence or absence of either 20 mM of MAP/ERK kinase MEK-1 inhibitor U0126 or 40 mM of PI3K inhibitor LY294002. Here, MCL1 is linked to infection.