Signaalikaskaade

Signaalikaskaade, often translated as signal cascade or signal transduction cascade, refers to a series of sequential biochemical events that occur within a cell in response to an external stimulus. This process begins when a signaling molecule, such as a hormone or neurotransmitter, binds to a specific receptor on the cell surface. This binding event triggers a cascade of intracellular reactions, typically involving the activation or deactivation of a series of enzymes or other signaling proteins.

Each step in the cascade amplifies the original signal, meaning that a small initial stimulus can ultimately lead to a significant cellular response. This amplification is crucial for enabling cells to detect and respond to even faint external cues. Common components of signal cascades include kinases, phosphatases, and second messengers like cyclic AMP (cAMP) or calcium ions. These molecules act as intermediaries, relaying the signal from one step to the next.

The ultimate outcome of a signal cascade can vary widely, depending on the specific pathway and the cell type involved. It can lead to changes in gene expression, alterations in cell metabolism, cell movement, or even programmed cell death. Signal cascades are fundamental to a vast array of cellular processes, including growth, differentiation, immune responses, and sensory perception. Dysregulation of these pathways can contribute to various diseases, making them important targets for pharmacological intervention.