G proteins and the mechanism of action of hormones, neurotransmitters, and autocrine and paracrine regulatory factors.
Signal transduction by G proteins is a fundamental and widespread mechanism used by a wide variety of hormones, neurotransmitters, and autocrine and paracrine factors to regulate cellular functions. G proteins modulate not only cAMP formation, but also intracellular Ca2+ mobilization, arachidonic acid release, and, very importantly, membrane potential. The mechanism by which G proteins are activated provides for amplification, reversal of action, and continued monitoring of incoming signals. Not all G proteins are known and some are known but their functions are still unknown. More G proteins and more effector functions affected by them will surely be found. We discuss these features of signal transduction by G proteins.
Birnbaumer
L
L
Department of Cell Biology, Baylor College of Medicine, Houston, Texas.
Brown
A M
AM
D001095:Arachidonic Acids / Q000378:metabolism; D001427:Bacterial Toxins / Q000494:pharmacology; D001685:Biological Factors / Q000502:physiology*; D002118:Calcium / Q000378:metabolism; D000242:Cyclic AMP / Q000096:biosynthesis; D019204:GTP-Binding Proteins / Q000502:physiology*; D006728:Hormones / Q000502:physiology*; D006801:Humans; D008564:Membrane Potentials; D018377:Neurotransmitter Agents / Q000502:physiology*; D011956:Receptors, Cell Surface / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology
D001095:Arachidonic Acids; D001427:Bacterial Toxins; D001685:Biological Factors; D006728:Hormones; D018377:Neurotransmitter Agents; D011956:Receptors, Cell Surface; D000242:Cyclic AMP; D019204:GTP-Binding Proteins; D002118:Calcium