BI110 Lecture Notes - Lecture 9: Signal Transduction, Cell Membrane, Conformational Change
Document Summary
The binding of a signal molecule to a plasma membrane receptor, for example, is sufficient to trigger the activation of a signalling cascade. Binding of a signal molecule to a surface receptor triggers the cellular response, and the signal molecule does not enter the cell. Unrelated molecules can trigger or block a full cellular response if they can bind to the recognition site of the receptor. Signal relayed in cell by target proteins: continuously active. Protein kinases often act in a chain, catalyzing a series of phosphorylation reactions called a phosphorylation cascade to pass along a signal. Each kinase catalyzes phosphorylation of another in the cascade, the last protein in the cascade is the target protein. Increases the magnitude of each step as a signal transduction pathway proceeds. Each activated enzyme in a pathway can activate hundreds of proteins (enzymes) in the next step in the pathway. The more enzyme-catalyzed steps in a response pathway, the greater the amplification.
