Signal transduction is the process by which a chemical or physical signal is transmitted through a cell as a series of molecular events. It is the transmission of molecular signals from a cells exterior to its interior. The process involves three main steps: reception, transduction, and response. Here is a breakdown of each step:
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Reception: A signaling molecule binds to a receptor protein on the cell surface or inside the cell. This binding changes the receptor protein in some way, which initiates the process of transduction.
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Transduction: The binding of the signaling molecule to the receptor protein initiates a series of molecular events, often involving a pathway of several steps. Each relay molecule in the signal transduction pathway changes the next molecule in the pathway. The signal can be amplified, so that one signaling molecule can generate a response involving hundreds to millions of molecules.
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Response: Finally, the signal triggers a specific cellular response. This response can be anything from a change in gene expression to a change in cell behavior.
Signal transduction can be initiated by a variety of stimuli, including extracellular cues like the presence of a growth factor, or intracellular events like DNA damage. The process can be characterized by delay, noise, signal feedback and feedforward, and interference, which can range from negligible to pathological.
