Signal transduction through protein action is through G protein coupled receptors (GPCR). Binding of different types of signal molecules to G protein couple receptors is a general mechanism of signal transduction.
G proteins act as an intermediary to a stimulation of a receptor. When an extracellular messenger, the hormone (H) combines with the specific receptor (R) on the plasma membrane. The H-R complex activates the regulatory components of G proteins. The G-protein inturn will interact with the effect proteins which may be enzymes or ion channel proteins, which result in the desired effect.
