Established and potential physiological roles of bicarbonate-sensing soluble adenylyl cyclase (sAC) in aquatic animals

TitleEstablished and potential physiological roles of bicarbonate-sensing soluble adenylyl cyclase (sAC) in aquatic animals
Publication TypeJournal Article
Year of Publication2014
AuthorsTresguerres M, Barott KL, Barron ME, Roa J.N
JournalJournal of Experimental Biology
Date Published2014/03
Type of ArticleReview
ISBN Number0022-0949
Accession NumberWOS:000332041600012
Keywordsacid-base status; Acid/base; alkaline tide; cAMP; Carbonic anhydrase; cyclic-amp; dogfish; dogfish squalus-acanthias; nuclear camp microdomain; pH sensing; protein-kinase-a; Proton pump; sperm motility; spiny; unique diterpene activator; V-ATPase; v-h+-atpase

Soluble adenylyl cyclase (sAC) is a recently recognized source of the signaling molecule cyclic AMP (cAMP) that is genetically and biochemically distinct from the classic G-protein-regulated transmembrane adenylyl cyclases (tmACs). Mammalian sAC is distributed throughout the cytoplasm and it may be present in the nucleus and inside mitochondria. sAC activity is directly stimulated by HCO3-, and sAC has been confirmed to be a HCO3- sensor in a variety of mammalian cell types. In addition, sAC can functionally associate with carbonic anhydrases to act as a de facto sensor of pH and CO2. The two catalytic domains of sAC are related to HCO3--regulated adenylyl cyclases from cyanobacteria, suggesting the cAMP pathway is an evolutionarily conserved mechanism for sensing CO2 levels and/or acid/base conditions. Reports of sAC in aquatic animals are still limited but are rapidly accumulating. In shark gills, sAC senses blood alkalosis and triggers compensatory H+ absorption. In the intestine of bony fishes, sAC modulates NaCl and water absorption. And in sea urchin sperm, sAC may participate in the initiation of flagellar movement and in the acrosome reaction. Bioinformatics and RT-PCR results reveal that sAC orthologs are present in most animal phyla. This review summarizes the current knowledge on the physiological roles of sAC in aquatic animals and suggests additional functions in which sAC may be involved.

Short TitleJ. Exp. Biol.
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