MAPK3 and infection: Results showed that at 4 days post transfection, the protein amount of MEK1/2 was reduced by ∼40% in MEK1/2 knockdown group, which resulted in the partial inhibition of the phosphorylation of ERK1/2 (∼30%), as well as the infection of A. phagocytophilum (∼50%)(Figure 8D).