An intracellular protein kinase cascade containing at least a MAPK, a MAPKK and a MAP3K. The cascade can also contain an additional tiers: the upstream MAP4K. The kinases in each tier phosphorylate and activate the kinase in the downstream tier to transmit a signal within a cell. [ GOC:bf http://www.ncbi.nlm.nih.gov/pubmed/9561267 GOC:mtg_signaling_feb11 http://www.ncbi.nlm.nih.gov/pubmed/20811974 ]
Synonyms: MAPKKK cascade mitogen-activated protein kinase cascade MAP kinase kinase kinase cascade MAP kinase cascade MAPK signal transduction
Term information
MAPK cascades lie downstream of many cell surface receptors and cooperate in transmitting various extracellular signals to the nucleus. One way by which the specificity of each cascade is regulated is through the existence of several distinct components in each tier of the different cascades. The cascades are typically named according to the component in the MAPK tier.