AP BIOLOGY

Detailed explanation-1: -Mitogen-activated protein kinase (MAPK) cascades are universal signal transduction modules in eukaryotes, including yeasts, animals and plants. These protein phosphorylation cascades link extracellular stimuli to a wide range of cellular responses.

Detailed explanation-2: -Summary: The mitogen-activated protein kinases (MAPKs) regulate diverse cellular programs by relaying extracellular signals to intracellular responses. In mammals, there are more than a dozen MAPK enzymes that coordinately regulate cell proliferation, differentiation, motility, and survival.

Detailed explanation-3: -MAP kinases are activated within protein kinase cascades that regulate cell proliferation, differentiation, and death. In mammals, MAP kinases are grouped into three families: ERKs, JNKs, and p38/SAPKs.

Detailed explanation-4: -The upstream canonical cascade links a growth factor-induced dimer of receptor tyrosine kinases to sequential activation of Ras, Raf, and Mek, which is a dual-specificity kinase that phosphorylates Erk. The phosphorylated form of Erk decays very rapidly, primarily through the action of double-specificity phosphatases.