This gene encodes a member of the mitogen-activated protein kinase (MAPK) family. Members of this family act as an integration point for multiple biochemical signals and are involved in a wide variety of cellular processes such as proliferation, differentiation, transcription regulation, and development. They form a three-tiered signaling module composed of MAPKKKs, MAPKKs, and MAPKs. This protein is phosphorylated at serine and threonine residues by MAPKKKs and subsequently phosphorylates downstream MAPK targets at threonine and tyrosine residues. A similar protein in mouse has been reported to play a role in liver organogenesis. A pseudogene of this gene is located on the long arm of chromosome X. Alternative splicing results in multiple transcript variants.,MAP2K4,JNKK,JNKK1,MAPKK4,MEK4,MKK4,PRKMK4,SAPKK-1,SAPKK1,SEK1,SERK1,SKK1,Signal Transduction,G protein signaling,G2/M DNA Damage Checkpoint,Kinase,Tyrosine kinases,ErbB-HER Signaling Pathway,MAPK-JNK Signaling Pathway,MAPK-P38 Signaling Pathway,Cell Biology & Developmental Biology,Cytoskeleton,Actins,TGF-b-Smad Signaling Pathway,Immunology & Inflammation,B Cell Receptor Signaling Pathway,T Cell Receptor Signaling Pathway,IL-6 Receptor Signaling Pathway,Toll-like Receptor Signaling Pathway,Neuroscience,Neurodegenerative Diseases,Dopamine Signaling in Parkinson's Disease,MAP2K4