MAPK Pathway

The Mitogen-Activated Protein Kinase (MAPK) signaling pathway represents a fundamental and highly conserved system in eukaryotic cells, orchestrating a vast array of cellular processes from proliferation and differentiation to stress responses, apoptosis, and inflammation. Often described as a three-tiered kinase cascade, it involves sequential phosphorylation events: a MAPK kinase kinase (MAPKKK or MEKK) phosphorylates and activates a MAPK kinase (MAPKK or MKK), which then phosphorylates and activates a MAPK. This phosphorylation typically occurs on specific threonine and tyrosine residues within the MAPK's activation loop.