Signal transduction Essay Example | Topics and Well Written Essays - 500 words

Signal transduction - Essay Example romolecules such as glycogen, protein and triglycerides, and the uptake of nutrients like fatty acids, amino acids and glucose by liver, muscle and adipose tissue. Insulin starts its action by binding to a receptor on the outer surface membrane of the cell membrane of its many target cells. This triggers the activation of insulin receptor, which signals the target cells on the regulation of chemical mediators. There are two types of subunits in the insulin receptor - ÃŽ ±-subunit and the ÃŽ ²-subunit. The ÃŽ ±-subunit is where insulin binds, while the ÃŽ ²-subunit cross the membrane and jut into the cytosol. The ÃŽ ±-subunit activates the protein tyrosine kinase, which is associated with the ÃŽ ²-subunit. The ÃŽ ²-subunit subsequently phosphorylates tyrosine into a number of residues like Tyr-960 and to a number of enzymes found inside the cytosol. The phosphorylation of the tyrosine residues stimulates an interaction between the isoforms and receptor of the insulin receptor substrate 1 (IRS-1). This substrate then recognizes and attaches to various signal transduction proteins in sections known as SH2 domains. Many of the physiological responses to insulin engage the IRS-1 through complex mechanisms involving intensive investigation. The action of adrenaline on liver cells and muscles was the first process to be used to describe the signal-transduction mechanism. Adrenaline is attached on receptor molecules in the cell membrane. It speeds the breakdown of glycogen in liver cells. Its molecules connect to the receptor molecules in the cell membrane. The guanine nucleotide-binding protein (G-protein) found in the membrane is activated by the formation of a hormone-receptor complex. The protein acts as a relay between an enzyme called adenyl cyclase and the hormone-receptor complex. The enzyme helps in catalyzing the conversation between ATP and cyclic adenine monophosphate(cAMP) in the liver cell. cAMP is a small molecule that acts as an intracellular mediator or a second