We have analyzed here the impact of ERK1 deficiency (ERK2 knockout mice die in utero18) and STAT1 S727A modification on several macrophage processes relevant to atherosclerosis in vitro and on the development of the disease in LDL receptor deficient mice (LDLR−/−) fed a high fat diet in vivo. This evidence concerns the gene MAPK1 and atherosclerosis.