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

2016 ◽  
Vol 311 (2) ◽  
pp. C340-C349 ◽  
Author(s):  
Jinae N. Roa ◽  
Martin Tresguerres

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.

2021 ◽  
Vol 11 (2) ◽  
pp. 20200026
Author(s):  
Cristina Salmerón ◽  
Till S. Harter ◽  
Garfield T. Kwan ◽  
Jinae N. Roa ◽  
Salvatore D. Blair ◽  
...  

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.


Author(s):  
Jung-Chin Chang ◽  
Simei Go ◽  
Eduardo H. Gilglioni ◽  
Hang Lam Li ◽  
Hsu-Li Huang ◽  
...  

AbstractCyclic AMP is produced in cells by two very different types of adenylyl cyclases: the canonical transmembrane adenylyl cyclases (tmACs, ADCY1∼9) and the evolutionarily more conserved soluble adenylyl cyclase (sAC, ADCY10). While the role and regulation of tmACs is well documented, much less is known of sAC in cellular metabolism. We demonstrate here that sAC is an acute regulator of glycolysis, oxidative phosphorylation and glycogen metabolism, tuning their relative bioenergetic contributions. Suppression of sAC activity leads to aerobic glycolysis, enhanced glycogenolysis, decreased oxidative phosphorylation, and an elevated cytosolic NADH/NAD+ ratio, resembling the Warburg phenotype. Importantly, we found that glycogen metabolism is regulated in opposite directions by cAMP depending on its location of synthesis and downstream effectors. While the canonical tmAC-cAMP-PKA axis promotes glycogenolysis, we identify a novel sAC-cAMP-Epac1 axis that suppresses glycogenolysis. These data suggest that sAC is an autonomous bioenergetic sensor that suppresses aerobic glycolysis and glycogenolysis when ATP levels suffice. When the ATP level falls, diminished sAC activity induces glycogenolysis and aerobic glycolysis to maintain energy homeostasis.


2009 ◽  
Vol 297 (1) ◽  
pp. L73-L83 ◽  
Author(s):  
Nutan Prasain ◽  
Mikhail Alexeyev ◽  
Ron Balczon ◽  
Troy Stevens

Soluble adenylyl cyclase toxins, such as Pseudomonas aeruginosa exoY, generate a cAMP pool that retracts cell borders. However, the cytoskeletal basis by which this cAMP signal retracts cell borders is not known. We sought to determine whether activation of chimeric, soluble adenylyl cyclase I/II (sACI/II) reorganizes either microtubules or peripheral actin. Endothelial cells were stably transfected with either green fluorescent protein-labeled α-tubulin or β-actin, and then infected with adenovirus to express sACI/II. Forskolin, which stimulates both the endogenously expressed transmembrane adenylyl cyclases and sACI/II, induced cell retraction accompanied by the reorganization of peripheral microtubules. However, cortical filamentous-actin (f-actin) did not reorganize into stress fibers, and myosin light-chain-20 phosphorylation was decreased. Isoproterenol, which activates endogenous adenylyl cyclases but does not activate sACI/II, did not induce endothelial cell gaps and did not influence microtubule or f-actin architecture. Thus, sACI/II generates a cAMP signal that reorganizes microtubules and induces cell retraction, without inducing f-actin stress fibers. These findings illustrate that endothelial cell gap formation can proceed without f-actin stress fiber formation, and provide mechanistic insight how bacterial adenylyl cyclase toxins reorganize the cytoskeleton to induce cell rounding.


2019 ◽  
Vol 2019 (4) ◽  
Author(s):  
Carmen W. Dessauer ◽  
Rennolds Ostrom ◽  
Roland Seifert ◽  
Val J. Watts

Adenylyl cyclase, E.C. 4.6.1.1, converts ATP to cyclic AMP and pyrophosphate. Mammalian membrane-delimited adenylyl cyclases (nomenclature as approved by the NC-IUPHAR Subcommittee on Adenylyl cyclases [9]) are typically made up of two clusters of six TM domains separating two intracellular, overlapping catalytic domains that are the target for the nonselective activators Gαs (the stimulatory G protein α subunit) and forskolin (except AC9, [21]). adenosine and its derivatives (e.g. 2',5'-dideoxyadenosine), acting through the P-site,are inhibitors of adenylyl cyclase activity [27]. Four families of membranous adenylyl cyclase are distinguishable: calmodulin-stimulated (AC1, AC3 and AC8), Ca2+- and Gβγ-inhibitable (AC5, AC6 and AC9), Gβγ-stimulated and Ca2+-insensitive (AC2, AC4 and AC7), and forskolin-insensitive (AC9) forms. A soluble adenylyl cyclase (AC10) lacks membrane spanning regions and is insensitive to G proteins.It functions as a cytoplasmic bicarbonate (pH-insensitive) sensor [5].


2005 ◽  
Vol 289 (5) ◽  
pp. C1145-C1151 ◽  
Author(s):  
Yan Wang ◽  
Chak Sum Lam ◽  
Fan Wu ◽  
Wen Wang ◽  
Yuanyuan Duan ◽  
...  

CFTR channels conduct HCO3− in addition to Cl− in airway epithelial cells. A defective HCO3−-transporting function of CFTR may underlie the pathogenesis of cystic fibrosis. In the present study, we have investigated whether a HCO3−-sensitive soluble adenylyl cyclase (sAC) is functionally coupled with CFTR and thus forms an autoregulatory mechanism for HCO3− transport in human airway epithelial Calu-3 cells. A reverse transcriptase-polymerase chain reaction showed that transcripts of both full-length and truncated sACs are present in Calu-3 cells. Truncated sAC protein is the predominant, if not the only, isoform expressed in Calu-3 cells. HCO3− stimulated a modest increase in cAMP production, and the increase was sensitive to 2-hydroxyestradiol (2-HE), a sAC inhibitor, but not to SQ22,536, a blocker of conventional transmembrane adenylyl cyclases. These results suggest that sAC is functional in Calu-3 cells. Adding 25 mM HCO3− to the bath stimulated CFTR-mediated whole cell currents in the absence, but not in the presence, of 2-HE. In cell-attached membrane patches, 25 or 50 mM HCO3− in the bath markedly increased the product of channel number and open probability of CFTR, and this activation was attenuated by 2-HE. These findings demonstrate that sAC signaling pathway is involved in the regulation of CFTR function in human airway epithelium and thereby provides a link between the level of intracellular HCO3−/CO2 and the modulation of HCO3−-conductive CFTR function by cAMP/PKA.


2008 ◽  
Vol 294 (1) ◽  
pp. F130-F138 ◽  
Author(s):  
Teodor G. Păunescu ◽  
Nicolas Da Silva ◽  
Leileata M. Russo ◽  
Mary McKee ◽  
Hua A. J. Lu ◽  
...  

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.


2013 ◽  
Vol 27 (S1) ◽  
Author(s):  
Martin Tresguerres ◽  
Megan E. Barron ◽  
Katie L. Barott ◽  
Jason Ho ◽  
Jinae N. Roa

2021 ◽  
Vol 22 (9) ◽  
pp. 4641
Author(s):  
Thi Mong Diep Nguyen ◽  
Laura Filliatreau ◽  
Danièle Klett ◽  
Nong Van Hai ◽  
Nguyen Thuy Duong ◽  
...  

In contrast to all transmembrane adenylyl cyclases except ADCY9, the cytosolic soluble adenylyl cyclase (ADCY10) is insensitive to forskolin stimulation and is uniquely modulated by calcium and bicarbonate ions. In the present paper, we focus on ADCY10 localization and a kinetic analysis of intracellular cAMP accumulation in response to human LH in the absence or presence of four different ADCY10 inhibitors (KH7, LRE1, 2-CE and 4-CE) in MTLC-1 cells. ADCY10 was immuno-detected in the cytoplasm of MLTC-1 cells and all four inhibitors were found to inhibit LH-stimulated cAMP accumulation and progesterone level in MLTC-1 and testosterone level primary Leydig cells. Interestingly, similar inhibitions were also evidenced in mouse testicular Leydig cells. In contrast, the tmAC-specific inhibitors ddAdo3′ and ddAdo5′, even at high concentration, exerted weak or no inhibition on cAMP accumulation, suggesting an important role of ADCY10 relative to tmACs in the MLTC-1 response to LH. The strong synergistic effect of HCO3− under LH stimulation further supports the involvement of ADCY10 in the response to LH.


2009 ◽  
Vol 107 (1) ◽  
pp. 442-447 ◽  
Author(s):  
M. Tresguerres ◽  
S. K. Parks ◽  
E. Salazar ◽  
L. R. Levin ◽  
G. G. Goss ◽  
...  

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