MAP Kinase Signalling Module

 The mitogen-activated protein (MAP) kinase module is a cell signalling pathway that has been highly conserved in eukaryotes and is used, with variations, in many different signalling contexts. It consists of 3 protein kinase components MAP kinase, MAP kinase kinase and Map kinase kinase kinase, also known as Erk, Mek and Raf respectively. On stimulation Raf phosphorylates and activates Mek, which in turn phosphorylates and activates Erk. Each one of these phosphorylation cascades acts to amplify the signal, so a small stimulus can lead to a large cellular response. After this amplification, Erk is capable of phosphorylating effector proteins, which on activation/inactivation change their chemical activity within the cell, or up/down regulate the expression of certain genes  [1].