MNK2 (MAP kinase-interacting kinase 2) contains a conserved C-terminal ERK-interacting domain, a catalytic domain with homology to the calcium/calmodulin-dependent family of kinases, and putative MAP kinase phosphorylation sites located within the T loop of the kinase domain. MNK2 binds tightly to the growth factor-regulated MAP kinases, ERK1 and ERK2. ERK and p38 phosphorylate MNK2, which stimulates its in vitro kinase activity toward a substrate, eukaryotic initiation factor-4E (eIF-4E) (1). A yeast two-hybrid screen showed the Mnk2 protein interacted with the ligand-binding domain of estrogen receptor beta (ERbeta) (2).