Kinase Family STE20
STE20 kinases are best known as members of the MAPK cascade. Many of them are MAP3K kinases that phosphorylate MAP2K (STE7, MEK) kinases, which in turn phosphorylate MAPK like Erk, Jnk, and p38. However, several subfamilies of STE20 may be only partially involved in MAPK cascades.
STE20 kinases are found in almost all eukaryotes, with Plasmodium being a notable exception.