Involved in both the initiation and regulation of meiosis, mitosis, and postmitotic functions in differentiated cells by phosphorylating a number of transcription factors such as ELK-1. Phosphorylates EIF4EBP1, required for initiation of translation. Phosphorylates microtubule-associated protein 2 (MAP2). Phosphorylates SPZ1. Phosphorylates heat shock factor protein 4(HSF4) (By similarity). Highest levels within the nervous system, expressed in different tissues, mostly in intestine, placenta and lung. Increased expression during development. Belongs to the protein kinase superfamily. CMGC Ser/Thr protein kinase family. MAP kinase subfamily. Contains 1 protein kinase domain. Binds both upstream activators and downstream substrates in multimolecular complexes. Found in a complex with at least BRAF, HRAS, MAP2K1/MEK1, MAPK3 and RGS14. Interacts with TPRBy similarity. Interacts with ADAM15, ARRB2, CANX, DAPK1 (via death domain), HSF4, IER3, MAP2K1/MEK1, NISCH, and SGK1By similarity. Interacts with MORG1, PEA15 and MKNK2. MKNK2 isoform 1 binding prevents from dephosphorylation and inactivation.