Signal transduction
Process transmitting chemical or physical signals through cells.
Signal transduction is the process by which a chemical or physical signal is transmitted through a cell as a series of molecular events. Proteins responsible for detecting stimuli are generally termed receptors, although in some cases the term sensor is used. The changes elicited by ligand binding (or signal sensing) in a receptor give rise to a biochemical cascade, which is a chain of biochemical events known as a signaling pathway. When signaling pathways interact with one another they form networks, which allow cellular responses to be coordinated, often by combinatorial signaling events. These molecular events are the basic mechanisms controlling cell growth, proliferation, metabolism and many other processes. In multicellular organisms, signal transduction pathways regulate cell communication in a wide variety of ways.
- field
- Cell biology, biochemistry
- known_for
- Transmission of chemical or physical signals through cells via molecular events, including receptors, signaling pathways, and networks
Lore & Background
Signal transduction involves the transformation of a stimulus into a biochemical signal. Stimuli can range from extracellular cues, such as the presence of epidermal growth factor, to intracellular events like DNA damage from replicative telomere attrition. The majority of pathways involve binding of signaling molecules, known as ligands, to receptors that trigger events inside the cell. Ligands include growth factors, cytokines, neurotransmitters, and steroid hormones. Some receptors, such as HER2, can be activated without ligands when overexpressed or mutated, leading to constitutive pathway activation and potentially cancer.
Reader's Guide
Signal transduction is fundamental to cellular function, governing processes from growth and proliferation to metabolism and cell communication. Each component of a signaling pathway is classified by its role relative to the initial stimulus: ligands are first messengers, receptors are signal transducers, and they activate primary effectors, often linked to second messengers. Signals can be amplified so that one signaling molecule generates a response involving hundreds to millions of molecules. Transduction is characterized by delay, noise, feedback, feedforward, and interference. With computational biology, analysis of signaling pathways and networks has become essential for understanding cellular functions and disease, including signaling rewiring underlying acquired drug resistance.
Did You Know?
- Proteins responsible for detecting stimuli are generally termed receptors, though in some cases the term sensor is used.
- Ligands are termed first messengers, while receptors are the signal transducers that activate primary effectors.
- Some receptors such as HER2 are capable of ligand-independent activation when overexpressed or mutated, leading to constitutive pathway activation.
- The transduction of biological signals is characterised by delay, noise, signal feedback and feedforward and interference.
Frequently Asked Questions
Who is Signal transduction?
Signal transduction is the cellular process that relays a chemical or physical stimulus through a chain of molecular events inside a cell. Think of it as the cell's internal messaging system, converting an external or internal cue into a specific downstream action.
What are Signal transduction's powers?
Its core toolkit includes receptors (or sensors) that detect ligands and environmental cues, biochemical cascades that amplify and relay the message, and signaling pathways that carry information to its target. When multiple pathways cross-talk, they form networks that let a cell coordinate complex, combinatorial responses.
How does Signal transduction's story end?
The narrative concludes when the final molecular event triggers a defined cellular response, such as altered gene expression, a shift in metabolism, or a change in cell behavior. The signal is then typically switched off so the cell can reset and remain ready for the next stimulus.
Why is Signal transduction important?
Without it, cells could not sense hormones, growth factors, or physical cues and translate them into action. It is the fundamental mechanism that allows trillions of individual cells in a multicellular organism to communicate and behave as a coordinated whole.
Who are Signal transduction's recurring sidekicks?
Receptors serve as the entry point, while second messengers, kinases, and other relay proteins carry and amplify the message through the cascade. Together they ensure the original stimulus is diversified and delivered to the correct intracellular target.
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