Right diagram: logical "OR" in a cell signaling pathway. An intermediate must phosphorylated on a single residue in order to become active and produce a response, and either of two pathways can phosphorylate the same residue. The response occurs if the first pathway OR the second pathway is active.How do signal transduction pathways amplify a signal?
Many signal transduction pathways amplify the initial signal, so that one molecule of ligand can lead to the activation of many molecules of a downstream target. The molecules that relay a signal are often proteins.What are the three types of kinase signaling pathways?
Together, Raf, MEK, and the ERKs make up a three-tiered kinase signaling pathway called a mitogen-activated protein kinase ( MAPK) cascade. (A mitogen is a signal that causes cells to undergo mitosis, or divide.)What are MAPK kinase signals?
MAP kinase signaling pathways are widespread in biology: they are found in a wide range of organisms, from humans to yeast to plants. The similarity of MAPK cascades in diverse organisms suggests that this pathway emerged early in the evolutionary history of life and was already present in a common ancestor of modern-day animals, plants, and fungi.