Publication Date:
1984-09-21
Description:
The adenylate cyclase system is composed of an activating hormone or neurotransmitter (H), its receptor (R), the guanosine triphosphate (GTP) binding protein (Gs), and the catalytic unit (C). The activation of the receptor R involves a transient change in conformation, from a loose binding of the neurotransmitter H to an extremely tight interaction, termed locking. The system is regulated in the activation steps and also by three deactivation processes. A guanosine triphosphatase activity is built into the Gs protein so that the active GsGTP has only a limited lifetime during which it is able to activate C. In addition, the continued occupation of R by H causes desensitization of R. Finally, there are inhibitory receptors, such as alpha-adrenergic and opiate receptors, which inhibit the adenylate cyclase by way of a specific GTP binding protein (Gi). Yet to be determined are the conformational transformations of pure R on binding of an agonist or a partial agonist; the genes that code for the many different receptors that activate the adenylate cyclase, and the possibility that the G components interact with systems in the cell other than the adenylate cyclase.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Schramm, M -- Selinger, Z -- AM10451/AM/NIADDK NIH HHS/ -- New York, N.Y. -- Science. 1984 Sep 21;225(4668):1350-6.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/6147897" target="_blank"〉PubMed〈/a〉
Keywords:
Adenylyl Cyclases/*metabolism
;
Animals
;
Cyclic AMP/*physiology
;
Enzyme Activation
;
GTP Phosphohydrolases/metabolism
;
GTP-Binding Proteins
;
Guanosine Diphosphate/metabolism
;
Guanosine Triphosphate/metabolism
;
Guanylyl Imidodiphosphate/metabolism
;
Membrane Lipids/physiology
;
Neurotransmitter Agents/physiology
;
Protein Conformation
;
Receptors, Cell Surface/metabolism
;
*Synaptic Transmission
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
,
Chemistry and Pharmacology
,
Computer Science
,
Medicine
,
Natural Sciences in General
,
Physics
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