MAP2K5 (Mitogen-Activated Protein Kinase Kinase 5): MAP2K5 is an enzyme that is part of the mitogen-activated protein kinase (MAPK) signaling pathway. It plays a key role in cellular responses to growth factors, stress, and cytokines. MAP2K5 is involved in processes such as cell growth, differentiation, and apoptosis, and its dysregulation can contribute to cancer and other diseases.