title: Bicarbonate-sensing soluble adenylyl cyclase is present in the cell cytoplasm and nucleus of multiple shark tissues.
abstract: The enzyme soluble adenylyl cyclase (sAC) is directly stimulated by bicarbonate (HCO3-) to produce the signaling molecule cyclic adenosine monophosphate (cAMP). Because sAC and sAC-related enzymes are found throughout phyla from cyanobacteria to mammals and they regulate cell physiology in response to internal and external changes in pH, CO2, and HCO3-, sAC is deemed an evolutionarily conserved acid-base sensor. Previously, sAC has been reported in dogfish shark and round ray gill cells, where they sense and counteract blood alkalosis by regulating the activity of V-type H+- ATPase. Here, we report the presence of sAC protein in gill, rectal gland, cornea, intestine, white muscle, and heart of leopard shark Triakis semifasciata Co-expression of sAC with transmembrane adenylyl cyclases supports the presence of cAMP signaling microdomains. Furthermore, immunohistochemistry on tissue sections, and western blots and cAMP-activity assays on nucleus-enriched fractions demonstrate the presence of sAC protein in and around nuclei. These results suggest that sAC modulates multiple physiological processes in shark cells, including nuclear functions.
authors.affiliation: Marine Biology Research Division, Scripps Institution of Oceanography University of California San Diego, 9500 Gilman Drive La Jolla, California, 92093, USA.
authors.forename: Jinae N
authors.initials: JN
authors.lastname: Roa
authors.affiliation: Marine Biology Research Division, Scripps Institution of Oceanography University of California San Diego, 9500 Gilman Drive La Jolla, California, 92093, USA mtresguerres@ucsd.edu.
authors.forename: Martin
authors.initials: M
authors.lastname: Tresguerres
mesh_terms: D000262:Adenylyl Cyclases / Q000302:isolation & purification*; D000818:Animals; D001639:Bicarbonates / Q000378:metabolism*; D002467:Cell Nucleus / Q000201:enzymology*; D003315:Cornea / Q000201:enzymology; D003593:Cytoplasm / Q000201:enzymology*; D007422:Intestines / Q000201:enzymology; D009206:Myocardium / Q000201:enzymology; D012491:Salt Gland / Q000201:enzymology; D012754:Sharks / Q000378:metabolism*
chemical_list: D001639:Bicarbonates; D000262:Adenylyl Cyclases
keywords: adcy10; cAMP; cyclic AMP; microdomain; pH sensing; phosphorylation; regulation of gene expression; signal transduction