MAPK3 and infection: ERK1/2 induction can be observed as early as 5 min p.i. by high and low multiplicity of infection of both live and UV-inactivated KSHV in the absence and presence of fetal calf serum in the cell culture medium, and PI3-K and PKC-ζ are the upstream mediators of ERK1/2 induction pathway [64].