MAPK, or Mitogen-Activated Protein Kinase, refers to a family of protein kinases that play a vital role in signal transduction pathways. These enzymes are serine/threonine kinases, meaning they primarily phosphorylate serine and threonine residues in target proteins. MAPKs are highly conserved in eukaryotes, with multiple isoforms found in various organisms.
MAPKs are activated in response to extracellular signals, such as growth factors, cytokines, hormones, and stress, to convey information from the cell surface to the nucleus. They function as key components in cellular processes including cell growth, proliferation, differentiation, survival, and apoptosis. Activation of MAPKs involves three-tiered phosphorylation cascades, where MAPK kinase kinases (MAPKKKs) phosphorylate MAPK kinases (MAPKKs), which in turn phosphorylate and activate MAPKs.
The MAPK family consists of several subgroups, including extracellular signal-regulated kinases (ERKs), c-Jun N-terminal kinases (JNKs), and p38 MAPKs, each associated with distinct physiological functions. ERKs predominantly regulate cell proliferation and differentiation, JNKs are involved in apoptosis and stress responses, while p38 MAPKs regulate inflammation, cell cycle arrest, and cellular stress responses.
Because of their significant involvement in cellular signaling, MAPK dysregulation has been implicated in various diseases, including cancer, neurodegenerative disorders, cardiovascular diseases, and inflammatory conditions. Consequently, MAPKs have emerged as important therapeutic targets, and the development of MAPK inhibitors has shown promise in treating these diseases.
In summary, MAPKs are a family of protein kinases that transduce extracellular signals into intracellular responses,
