MAPK3 and infection: Our results showed that in cells infected by P12ABCCC, as well as the corresponding P12ABFFF phosphorylation-deficient mutant, ERK1/2 activation occurred at similar significantly higher levels compared to strains P12AB and P12CagAKO, during the initial stages of infection (mean difference at 30 min of 1.97 and 95%CI 0.80 to 3.14 [P = 0.006], mean difference at 60 min of 1.06 and 95%CI of 0.27 to 1.84 [P = 0.004], mean difference at 90 min of 1.140 and 95%CI of 0.48 to 1.79 [P = 0.016]), suggesting that ERK1/2 activation is EPIYA-C motif phosphorylation-independent (Figure 4A and Figure 4B).