Regulation of coral calcification by the acid-base sensing enzyme soluble adenylyl cyclase

Activation of soluble adenylyl cyclase (sAC) by bicarbonate causes local cAMP generation, indicating that sAC might act as a pH and/or bicarbonate sensor in kidney cells involved in acid-base homeostasis. Therefore, we examined the expression of sAC in renal acid-base transporting intercalated cells (IC) and compared its distribution to that of the vacuolar proton pumping ATPase (V-ATPase) under different conditions. In all IC, sAC and V-ATPase showed considerable overlap under basal conditions, but sAC staining was also found in other cellular locations in the absence of V-ATPase. In type A-IC, both sAC and V-ATPase were apically and subapically located, whereas in type B-IC, significant basolateral colocalization of sAC and the V-ATPase was seen. When apical membrane insertion of the V-ATPase was stimulated by treatment of rats with acetazolamide, sAC was also concentrated in the apical membrane of A-IC. In mice that lack a functional B1 subunit of the V-ATPase, sAC was colocalized apically in A-IC along with V-ATPase containing the alternative B2 subunit isoform. The close association between these two enzymes was confirmed by coimmunoprecipitation of sAC from kidney homogenates using anti-V-ATPase antibodies. Our data show that sAC and the V-ATPase colocalize in IC, that they are concentrated in the IC plasma membrane under conditions that “activate” these proton secretory cells, and that they are both present in an immunoprecipitated complex. This suggests that these enzymes have a close association and could be part of a protein complex that is involved in regulating renal distal proton secretion.

Download Full-text

Sensing acid/base conditions via soluble adenylyl cyclase in aquatic animals

The FASEB Journal ◽

10.1096/fasebj.27.1_supplement.937.3 ◽

2013 ◽

Vol 27 (S1) ◽

Author(s):

Martin Tresguerres ◽

Megan E. Barron ◽

Katie L. Barott ◽

Jason Ho ◽

Jinae N. Roa

Keyword(s):

Adenylyl Cyclase ◽

Acid Base ◽

Aquatic Animals ◽

Soluble Adenylyl Cyclase

Download Full-text

Bicarbonate-sensing soluble adenylyl cyclase is an essential sensor for acid/base homeostasis

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.0911790107 ◽

2009 ◽

Vol 107 (1) ◽

pp. 442-447 ◽

Cited By ~ 59

Author(s):

M. Tresguerres ◽

S. K. Parks ◽

E. Salazar ◽

L. R. Levin ◽

G. G. Goss ◽

...

Keyword(s):

Adenylyl Cyclase ◽

Acid Base ◽

Soluble Adenylyl Cyclase

Download Full-text

Bicarbonate‐Stimulated Soluble Adenylyl Cyclase Is an Acid‐Base Sensor Present in the Cell Cytoplasm and Nucleus of Elasmobranch Fishes

The FASEB Journal ◽

10.1096/fasebj.31.1_supplement.719.19 ◽

2017 ◽

Vol 31 (S1) ◽

Author(s):

Jinae N Roa ◽

Martin Tresguerres

Keyword(s):

Adenylyl Cyclase ◽

Cell Cytoplasm ◽

Acid Base ◽

Soluble Adenylyl Cyclase ◽

Elasmobranch Fishes

Download Full-text

Molecular and biochemical characterization of the bicarbonate-sensing soluble adenylyl cyclase from a bony fish, the rainbow trout Oncorhynchus mykiss

Interface Focus ◽

10.1098/rsfs.2020.0026 ◽

2021 ◽

Vol 11 (2) ◽

pp. 20200026

Author(s):

Cristina Salmerón ◽

Till S. Harter ◽

Garfield T. Kwan ◽

Jinae N. Roa ◽

Salvatore D. Blair ◽

...

Keyword(s):

Rainbow Trout ◽

Adenylyl Cyclase ◽

Biochemical Characterization ◽

Protein Isoforms ◽

Adenylyl Cyclases ◽

Acid Base ◽

Soluble Adenylyl Cyclase ◽

Rainbow Trout Oncorhynchus Mykiss ◽

Bony Fishes ◽

Signalling Molecule

Soluble adenylyl cyclase (sAC) is a HC O 3 − -stimulated enzyme that produces the ubiquitous signalling molecule cAMP, and deemed an evolutionarily conserved acid–base sensor. However, its presence is not yet confirmed in bony fishes, the most abundant and diverse of vertebrates. Here, we identified sAC genes in various cartilaginous, ray-finned and lobe-finned fish species. Next, we focused on rainbow trout sAC (rtsAC) and identified 20 potential alternative spliced mRNAs coding for protein isoforms ranging in size from 28 to 186 kDa. Biochemical and kinetic analyses on purified recombinant rtsAC protein determined stimulation by HC O 3 − at physiologically relevant levels for fish internal fluids (EC 50 ∼ 7 mM). rtsAC activity was sensitive to KH7, LRE1, and DIDS (established inhibitors of sAC from other organisms), and insensitive to forskolin and 2,5-dideoxyadenosine (modulators of transmembrane adenylyl cyclases). Western blot and immunocytochemistry revealed high rtsAC expression in gill ion-transporting cells, hepatocytes, red blood cells, myocytes and cardiomyocytes. Analyses in the cell line RTgill-W1 suggested that some of the longer rtsAC isoforms may be preferentially localized in the nucleus, the Golgi apparatus and podosomes. These results indicate that sAC is poised to mediate multiple acid–base homeostatic responses in bony fishes, and provide cues about potential novel functions in mammals.

Download Full-text

Soluble adenylyl cyclase is an acid-base sensor in epithelial base-secreting cells

AJP Cell Physiology ◽

10.1152/ajpcell.00089.2016 ◽

2016 ◽

Vol 311 (2) ◽

pp. C340-C349 ◽

Cited By ~ 8

Author(s):

Jinae N. Roa ◽

Martin Tresguerres

Keyword(s):

Cell Membrane ◽

Adenylyl Cyclase ◽

Hormonal Regulation ◽

Cell Biology ◽

Cultured Cells ◽

Primary Cultures ◽

Specific Inhibitor ◽

Adenylyl Cyclases ◽

Acid Base ◽

Soluble Adenylyl Cyclase

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.

Download Full-text