Serine/threonine-protein kinase that phosphorylates SFPQ/PSF, HNRNPA1 and EIF4E. May play a role in the response to environmental stress and cytokines. Appears to regulate translation by phosphorylating EIF4E, thus increasing the affinity of this protein for the 7-methylguanosine-containing mRNA cap. Required for mediating PP2A-inhibition-induced EIF4E phosphorylation. Triggers EIF4E shuttling from cytoplasm to nucleus. Isoform 1 displays a high basal kinase activity, but isoform 2 exhibits a very low kinase activity. Acts as a mediator of the suppressive effects of IFNgamma on hematopoiesis. Negative regulator for signals that control generation of arsenic trioxide As(2)O(3)-dependent apoptosis and anti-leukemic responses. Involved in anti-apoptotic signaling in response to serum withdrawal. ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] Binds 1 zinc ion per subunit. Inhibited by CGP57380 and staurosporine. Activated by phosphorylation in a negative-feedback regulatory manner in response to chemotherapy (e.g. cytarabine) and thus impairs the generation of antileukemic responses. Monomer. Interacts with the C-terminal regions of EIF4G1 and EIF4G2; this interaction is promoted when MAPK pathways are repressed but repressed upon ERK proteins activation. Also binds to dephosphorylated MAPK3/ERK1 and MAPK1/ERK2. Isoform 1 interaction with phosphorylated MAPK3/ERK1 and MAPK1/ERK2 protects it from dephosphorylation and inactivation. Isoform 2 interacts with ESR2 and EIF4E in the nucleus. Ubiquitously expressed in all tissues examined. Isoform 2 is expressed at higher levels in the ovary than is isoform 1. Dual phosphorylation of Thr-244 and Thr-249 activates the kinase. Phosphorylation of Thr-379 activates the kinase. Phosphorylated upon arsenic trioxide As(2)O(3) treatment. Phosphorylated by MAPK1/ERK2, MAPK11 and MAPK14. Dephosphorylated by PP2A. Belongs to the protein kinase superfamily. CAMK Ser/Thr protein kinase family.