Signal transmission paths
Signal transmission paths Introduction Once the signaling molecule (ligand) of one cell binds to the receptor of another, is the signaling process complete? If we are talking about intracellular receptors that bind their ligand inside the cell and directly activate genes, the answer could be yes. In most cases, however, the answer is no, not at all! In the case of receptors located on the cell membrane, the signal must be transmitted by other molecules within the cell, in a kind of "telephone" game. The chains of molecules that transmit signals within a cell are known as intracellular signal transduction pathways. Here we will see the general characteristics of intracellular signal transduction pathways, as well as some transmission mechanisms commonly used in these pathways. Binding initiates a signaling pathway When a ligand binds to a cell surface receptor, the receptor's intracellular domain (the region inside the cell) changes in some way. It usually takes on a new f...