ERK3 (MAPK6) and ERK4 (MAPK4) were recently shown to be directly phosphorylated and thus activated by PAK kinases (related to other MAP3 kinases).
A ERK3 (MAPK6) e ERK4 (MAPK4) son fosforiladas directamente e, por tanto, activadas por quinases PAK (relacionadas con outras MAP3K).