Roles of Soluble Adenylyl Cyclase in cAMP Synthesis in Animal Cells

Abstract

The second messenger cyclic adenosine 3′,5′-monophosphate (cAMP) synthesis is catalyzed by adenylyl cyclases (ACs). The second messenger cAMP participates in many physiological processes in cells. All eukaryotic adenylyl cyclases (transmembrane adenylyl cyclase and soluble adenylyl cyclases) belong to class III. Soluble adenylyl cyclase was identified in many studies as a widely expressed intracellular source of cAMP in mammalian and non-mammalian cells. Soluble adenylyl cyclase is evolutionary, structurally, and biochemically distinct from the G-protein-responsive transmembrane adenylyl cyclase. sAC is distributed throughout the cytoplasm and it may be present in the nucleus and in mitochondria. sAC has been confirmed to be a bicarbonate sensor in a variety of mammalian cell types. Here I review the physiological role of soluble adenylyl cyclase in different mammalian and non-mammalian tissues. These data promote further research to clarify the exact roles of soluble adenylyl cyclase in the development of the biological activity of normal cells in the body and the therapeutic implications.