Cell signaling is a complex process that enables communication between cells and the transduction of a signal from the cell surface all the way to the nucleus. In order to efficiently transmit the signal a myriad of different proteins are required ranging from growth factors/ligands that bind to cell surface receptors to transcription factors altering gene expression patterns. Changes in the levels of biochemical molecules, like nitric oxide and cyclic GMP, and modifications, such as phosphorylation, ubiquitination, neddylation, and sumoylation, are the main ways to convey these signals.
Extensive research has enabled the elucidation of many cell signaling mechanisms and has resulted in the mapping of entire cell signaling pathways. These pathways, which are often named after their main kinase protagonists (e.g. MAP kinase pathway, PI3K-Akt pathway), feature sophisticated feedback loops and due to extensive cross-talk should be viewed as part of a larger network rather than a simplistic single pathway. Misregulation of cell signaling pathways has been implicated in a variety of diseases including cancer, type II diabetes and Parkinson’s disease. Based on this it is not surprising that a lot of effort has been put into developing targeted inhibitors against specific cell signaling molecules or protein interactions.