title: Soluble adenylyl cyclase is an acid-base sensor in epithelial base-secreting cells.
abstract: Blood acid-base regulation by specialized epithelia, such as gills and kidney, requires the ability to sense blood acid-base status. Here, we developed primary cultures of ray (Urolophus halleri) gill cells to study mechanisms for acid-base sensing without the interference of whole animal hormonal regulation. Ray gills have abundant base-secreting cells, identified by their noticeable expression of vacuolar-type H(+)-ATPase (VHA), and also express the evolutionarily conserved acid-base sensor soluble adenylyl cyclase (sAC). Exposure of cultured cells to extracellular alkalosis (pH 8.0, 40 mM HCO3 (-)) triggered VHA translocation to the cell membrane, similar to previous reports in live animals experiencing blood alkalosis. VHA translocation was dependent on sAC, as it was blocked by the sAC-specific inhibitor KH7. Ray gill base-secreting cells also express transmembrane adenylyl cyclases (tmACs); however, tmAC inhibition by 2',5'-dideoxyadenosine did not prevent alkalosis-dependent VHA translocation, and tmAC activation by forskolin reduced the abundance of VHA at the cell membrane. This study demonstrates that sAC is a necessary and sufficient sensor of extracellular alkalosis in ray gill base-secreting cells. In addition, this study indicates that different sources of cAMP differentially modulate cell biology.
authors.affiliation: Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego, La Jolla, California.
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, La Jolla, California mtresguerres@ucsd.edu.
authors.forename: Martin
authors.initials: M
authors.lastname: Tresguerres
mesh_terms: D000067956:Adenylyl Cyclase Inhibitors / Q000494:pharmacology; D000262:Adenylyl Cyclases / Q000378:metabolism*; D000471:Alkalosis / Q000378:metabolism / Q000503:physiopathology; D000818:Animals; D001639:Bicarbonates / Q000378:metabolism; D001692:Biological Transport / Q000187:drug effects / Q000502:physiology; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D002478:Cells, Cultured; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism; D016048:Dideoxyadenosine / Q000031:analogs & derivatives / Q000378:metabolism; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism* / Q000502:physiology*; D005880:Gills / Q000187:drug effects / Q000378:metabolism / Q000502:physiology; D006863:Hydrogen-Ion Concentration; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D012860:Skates, Fish / Q000378:metabolism / Q000502:physiology; D025262:Vacuolar Proton-Translocating ATPases / Q000378:metabolism
chemical_list: D000067956:Adenylyl Cyclase Inhibitors; D001639:Bicarbonates; D005576:Colforsin; D016048:Dideoxyadenosine; C021008:2',5'-dideoxyadenosine; D000242:Cyclic AMP; D025262:Vacuolar Proton-Translocating ATPases; D000262:Adenylyl Cyclases
keywords: cAMP; gill; pH sensing; proton pump; soluble adenylyl cyclase