Signaaltransductie: Overzicht

Signal transduction is a process where the binding of an extracellular messenger initiates a series of molecular reactions, leading to a cellular response.

When an extracellular ligand or a drug binds a receptor, it changes the receptors' conformation to activate it. These receptors can be G protein–coupled receptors or GPCRs, enzyme-linked receptors, nuclear receptors, or ligand-gated ion channels.

The activated receptors transmit and amplify the signal in different ways. Ion channels facilitate ion movement across the cell, changing the membrane potential and mediating cellular activities like neurotransmission and muscle contraction.

GPCRs associate with heterotrimeric G proteins to interact with effectors and produce second messengers.

In contrast, the enzyme-linked receptors have intracellular kinase domains that phosphorylate multiple downstream effectors to modulate gene expression.

Alternatively, lipophilic drugs or steroids cross the bilayer to bind cytosolic nuclear receptors. The drug-receptor complexes translocate to the nucleus and regulate gene transcription.