Gene Symbol: Scnn1a
Description: sodium channel epithelial 1 alpha subunit
Alias: ENaCA, amiloride-sensitive sodium channel subunit alpha, SCNEA, alpha-ENaC, alpha-NaCH, amiloride-sensitive epithelial sodium channel alpha subunit, epithelial Na(+) channel subunit alpha, epithelial sodium channel alpha subunit, nonvoltage-gated sodium channel 1 subunit alpha, sodium channel, non-voltage-gated 1 alpha subunit, sodium channel, nonvoltage-gated 1 alpha, sodium channel, nonvoltage-gated, type I, alpha
Species: rat
Products:     Scnn1a

Top Publications

  1. Zhong S, Liu Z. Immunohistochemical localization of the epithelial sodium channel in the rat inner ear. Hear Res. 2004;193:1-8 pubmed
    ..In conclusion, our results suggest that functional ENaC in the labyrinth may work in concert with other Na+ and K+ transport molecules to regulate endolymph and to maintain homeostasis in the inner ear. ..
  2. Ergonul Z, Frindt G, Palmer L. Regulation of maturation and processing of ENaC subunits in the rat kidney. Am J Physiol Renal Physiol. 2006;291:F683-93 pubmed
    ..Changes in the processing and maturation of the channels occur rapidly enough to be involved in the daily regulation of ENaC activity and Na reabsorption by the kidney. ..
  3. Caldwell R, Boucher R, Stutts M. Serine protease activation of near-silent epithelial Na+ channels. Am J Physiol Cell Physiol. 2004;286:C190-4 pubmed
    ..Modulation of ENaC Po by endogenous epithelial serine proteases is a potentially important regulator of epithelial Na+ transport, distinct from the regulation achieved by hormone-induced plasma membrane insertion of channels. ..
  4. Waldmann R, Champigny G, Lazdunski M. Functional degenerin-containing chimeras identify residues essential for amiloride-sensitive Na+ channel function. J Biol Chem. 1995;270:11735-7 pubmed
  5. Pylnik T, Pletneva L, Redina O, Smolenskaya S, Markel A, Ivanova L. The effect of emotional stress on the expression of the ?-ENaC gene mRNA in the kidney of hypertensive ISIAH rats. Dokl Biol Sci. 2011;439:201-3 pubmed publisher
  6. Zhou W, He L, Li T, You J. [Epithelial sodium channel subunit mRNA expression in acutely isolated rat alveolar type II cells]. Nan Fang Yi Ke Da Xue Xue Bao. 2009;29:54-6 pubmed
    ..As the predominant ENaC subunit expressed at the mRNA level in rat ATII cells, the alpha-subunit of ENAC plays an important role in alveolar fluid clearance. ..
  7. Ruete M, Carrizo L, Bocanegra M, Valles P. Altered renal expression of Na(+) transporters and ROMK in protein-deprived rats. Nephron Physiol. 2009;111:p17-29 pubmed publisher
    ..A role of aldosterone may be suggested. ..
  8. Collier D, Snyder P. Extracellular protons regulate human ENaC by modulating Na+ self-inhibition. J Biol Chem. 2009;284:792-8 pubmed publisher
    ..Together, the data support a model in which protons modulate ENaC gating by relieving Na(+) self-inhibition. We speculate that this may be an important mechanism to facilitate epithelial Na(+) transport under conditions of acidosis. ..
  9. Harvey K, Dinudom A, Komwatana P, Jolliffe C, Day M, Parasivam G, et al. All three WW domains of murine Nedd4 are involved in the regulation of epithelial sodium channels by intracellular Na+. J Biol Chem. 1999;274:12525-30 pubmed
    ..We propose that Nedd4-mediated down-regulation of Na+ channels involves the binding of WW domains 2 and 3 to the Na+ channel and of WW domain 1 to an unknown associated protein. ..

More Information


  1. Hobbs C, Blanchard M, Alijevic O, Tan C, Kellenberger S, Bencharit S, et al. Identification of the SPLUNC1 ENaC-inhibitory domain yields novel strategies to treat sodium hyperabsorption in cystic fibrosis airway epithelial cultures. Am J Physiol Lung Cell Mol Physiol. 2013;305:L990-L1001 pubmed publisher
    ..Furthermore, the robust inhibition of ENaC by the S18 peptide suggests that this peptide may be suitable for treating CF lung disease. ..
  2. Roux J, Kawakatsu H, Gartland B, Pespeni M, Sheppard D, Matthay M, et al. Interleukin-1beta decreases expression of the epithelial sodium channel alpha-subunit in alveolar epithelial cells via a p38 MAPK-dependent signaling pathway. J Biol Chem. 2005;280:18579-89 pubmed
    ..Moreover, IL-1beta decreased basal and dexamethasone-induced epithelial sodium channel alpha-subunit (alpha ENaC) mRNA levels and total and cell-surface protein expression...
  3. Hanukoglu I, Boggula V, Vaknine H, Sharma S, KLEYMAN T, Hanukoglu A. Expression of epithelial sodium channel (ENaC) and CFTR in the human epidermis and epidermal appendages. Histochem Cell Biol. 2017;147:733-748 pubmed publisher
    ..PHA patients may develop folliculitis, miliaria rubra, and atopic dermatitis-like skin lesions, due to sweat gland duct occlusion and inflammation of eccrine glands as a result of salt accumulation. ..
  4. Diakov A, Korbmacher C. A novel pathway of epithelial sodium channel activation involves a serum- and glucocorticoid-inducible kinase consensus motif in the C terminus of the channel's alpha-subunit. J Biol Chem. 2004;279:38134-42 pubmed
    ..This defines a novel regulatory pathway likely to be relevant for aldosterone-induced stimulation of ENaC in vivo. ..
  5. Teruyama R, Sakuraba M, Wilson L, Wandrey N, Armstrong W. Epithelial Na? sodium channels in magnocellular cells of the rat supraoptic and paraventricular nuclei. Am J Physiol Endocrinol Metab. 2012;302:E273-85 pubmed publisher
    ..These results strongly suggest the presence of functional ENaCs that may affect the firing patterns of MNCs, which ultimately control the secretion of VP and OT. ..
  6. de Seigneux S, Leroy V, Ghzili H, Rousselot M, Nielsen S, Rossier B, et al. NF-kappaB inhibits sodium transport via down-regulation of SGK1 in renal collecting duct principal cells. J Biol Chem. 2008;283:25671-81 pubmed publisher
    ..In conclusion, we show that activation of the NF-kappaB pathway down-regulates SGK1 expression, which might lead to decreased ENaC alpha-subunit expression, ultimately resulting in decreased Na(+) transport. ..
  7. Kong X, Ma H, Li H, Xiong C. Blockade of epithelial sodium channels improves sperm motility in asthenospermia patients. Int J Androl. 2009;32:330-6 pubmed publisher
    ..89% from 9.50 +/- 6.11% to 20.51 +/- 12.13% (mean +/- SEM, p < 0.001). The improved sperm motility by EIPA has important clinical implications in the treatment of asthenospermia and certainly warrants further investigation. ..
  8. Xie Y, Schafer J. Inhibition of ENaC by intracellular Cl- in an MDCK clone with high ENaC expression. Am J Physiol Renal Physiol. 2004;287:F722-31 pubmed
    ..91 +/- 0.16 to 1.32 +/- 0.17 fmol/cm2 and in the intrinsic channel activity (the average current per ENaC subunit) from 13.3 +/- 1.2 to 8.2 +/- 1.4 microA/fmol. ..
  9. Chang S, Grunder S, Hanukoglu A, Rosler A, Mathew P, Hanukoglu I, et al. Mutations in subunits of the epithelial sodium channel cause salt wasting with hyperkalaemic acidosis, pseudohypoaldosteronism type 1. Nat Genet. 1996;12:248-53 pubmed
    ..These findings demonstrate the molecular basis and explain the pathophysiology of this disease. ..
  10. Ahn Y, Brooker D, Kosari F, Harte B, Li J, Mackler S, et al. Cloning and functional expression of the mouse epithelial sodium channel. Am J Physiol. 1999;277:F121-9 pubmed
  11. Kanelis V, Rotin D, Forman Kay J. Solution structure of a Nedd4 WW domain-ENaC peptide complex. Nat Struct Biol. 2001;8:407-12 pubmed
    ..The Nedd4 WW domain-ENaC betaP2 peptide structure expands our understanding of the mechanisms involved in WW domain-ligand recognition and the molecular basis of Liddle syndrome. ..
  12. Farr T, Coddington Lawson S, Snyder P, McDonald F. Human Nedd4 interacts with the human epithelial Na+ channel: WW3 but not WW1 binds to Na+-channel subunits. Biochem J. 2000;345 Pt 3:503-9 pubmed
    ..In addition, when co-expressed in Xenopus oocytes, human Nedd4 down-regulates Na(+)-channel activity. ..
  13. Malbert Colas L, Nicolas G, Galand C, Lecomte M, Dhermy D. Identification of new partners of the epithelial sodium channel alpha subunit. C R Biol. 2003;326:615-24 pubmed
    ..All these partners are implicated in protein trafficking and could be involved in the regulation of ENaC activity. ..
  14. Chen L, Fuller C, Kleyman T, Matalon S. Mutations in the extracellular loop of alpha-rENaC alter sensitivity to amiloride and reactive species. Am J Physiol Renal Physiol. 2004;286:F1202-8 pubmed
    ..These data indicate that both tyrosines are important for proper ENaC function and their oxidative modifications contribute to altered ENaC function. ..
  15. Li T, Koshy S, Folkesson H. Involvement of {alpha}ENaC and Nedd4-2 in the conversion from lung fluid secretion to fluid absorption at birth in the rat as assayed by RNA interference analysis. Am J Physiol Lung Cell Mol Physiol. 2007;293:L1069-78 pubmed
    ..Thus we provide evidence that ENaC and Nedd4-2 are involved in the transition from lung fluid secretion to fluid absorption near term and at birth. ..
  16. Amin M, Reza E, El Shahat E, Wang H, Tesson F, Leenen F. Enhanced expression of epithelial sodium channels in the renal medulla of Dahl S rats. Can J Physiol Pharmacol. 2011;89:159-68 pubmed publisher
    ..R rats on regular salt, and further increased on high salt. The persistent high expression of ?ENaC and increase in apical localization of ? and ?ENaC may contribute to greater retention of sodium in S rats on a high-salt diet. ..
  17. Mazzochi C, Bubien J, Smith P, Benos D. The carboxyl terminus of the alpha-subunit of the amiloride-sensitive epithelial sodium channel binds to F-actin. J Biol Chem. 2006;281:6528-38 pubmed
    ..This is the first study to report a direct and specific biochemical interaction between F-actin and ENaC. ..
  18. Friedrich B, Feng Y, Cohen P, Risler T, Vandewalle A, Broer S, et al. The serine/threonine kinases SGK2 and SGK3 are potent stimulators of the epithelial Na+ channel alpha,beta,gamma-ENaC. Pflugers Arch. 2003;445:693-6 pubmed
    ..In conclusion, SGK2 and SGK3 mimic the function of SGK1 and are likely to participate in the regulation of ENaC activity. ..
  19. Staub O, Dho S, Henry P, Correa J, Ishikawa T, McGlade J, et al. WW domains of Nedd4 bind to the proline-rich PY motifs in the epithelial Na+ channel deleted in Liddle's syndrome. EMBO J. 1996;15:2371-80 pubmed
    ..These results demonstrate that the WW domains of rNedd4 bind to the PY motifs deleted from beta or gammaENaC in Liddle's syndrome patients, and suggest that Nedd4 may be a regulator (suppressor) of the epithelial Na+ channel. ..
  20. Plettenberg S, Weiss E, Lemor R, Wehner F. Subunits alpha, beta and gamma of the epithelial Na+ channel (ENaC) are functionally related to the hypertonicity-induced cation channel (HICC) in rat hepatocytes. Pflugers Arch. 2008;455:1089-95 pubmed
    ..It is concluded that all three subunits of the ENaC are functionally related to RVI and HICC activation in rat hepatocytes. ..
  21. West C, Zhang Z, Ecker G, Masilamani S. Increased renal alpha-epithelial sodium channel (ENAC) protein and increased ENAC activity in normal pregnancy. Am J Physiol Regul Integr Comp Physiol. 2010;299:R1326-32 pubmed publisher
    ..Further, we show that ENaC activity is a major contributor of plasma volume status in late pregnancy. These changes are likely to contribute to the renal sodium retention and plasma volume expansion required for an optimal pregnancy. ..
  22. Konstas A, Koch J, Korbmacher C. cAMP-dependent activation of CFTR inhibits the epithelial sodium channel (ENaC) without affecting its surface expression. Pflugers Arch. 2003;445:513-21 pubmed
    ..We conclude that the inhibitory effect of cAMP-activated CFTR on ENaC is due to a decrease in channel open probability. ..
  23. Bhalla V, Daidié D, Li H, Pao A, LaGrange L, Wang J, et al. Serum- and glucocorticoid-regulated kinase 1 regulates ubiquitin ligase neural precursor cell-expressed, developmentally down-regulated protein 4-2 by inducing interaction with 14-3-3. Mol Endocrinol. 2005;19:3073-84 pubmed
    ..These results demonstrate a novel, physiologically significant role for 14-3-3 proteins in modulating ubiquitin ligase-dependent pathways in the control of epithelial ion transport. ..
  24. Ishikawa T, Jiang C, Stutts M, Marunaka Y, Rotin D. Regulation of the epithelial Na+ channel by cytosolic ATP. J Biol Chem. 2003;278:38276-86 pubmed
    ..We propose that this novel ATP regulation of ENaC may be, at least in part, involved in the fine-tuning of ENaC activity under physiologic and pathophysiologic conditions. ..
  25. Vasquez M, Castro R, Seidner S, Henson B, Ashton D, Mustafa S. Induction of serum- and glucocorticoid-induced kinase-1 (SGK1) by cAMP regulates increases in alpha-ENaC. J Cell Physiol. 2008;217:632-42 pubmed publisher
    ..Increased alpha-ENaC levels and function are partly dependent upon the early induction of SGK1 expression. ..
  26. Machida K, Nonoguchi H, Wakamatsu S, Inoue H, Yosifovska T, Inoue T, et al. Acute regulation of the epithelial sodium channel gene by vasopressin and hyperosmolality. Hypertens Res. 2003;26:629-34 pubmed
    ..Determining the physiological significance of the acute effect of vasopressin in MAL will require further investigations. ..
  27. Wakida N, Kitamura K, Tuyen D, Maekawa A, Miyoshi T, Adachi M, et al. Inhibition of prostasin-induced ENaC activities by PN-1 and regulation of PN-1 expression by TGF-beta1 and aldosterone. Kidney Int. 2006;70:1432-8 pubmed
    ..PN-1 could represent a new factor that contributes to regulation of ENaC activity in the kidney. ..
  28. Canessa C, Horisberger J, Rossier B. Epithelial sodium channel related to proteins involved in neurodegeneration. Nature. 1993;361:467-70 pubmed
    ..We propose that the gene products of these three genes are members of a gene family coding for cation channels. ..
  29. Kim S, Wang W, Nielsen J, Praetorius J, Kwon T, Knepper M, et al. Increased expression and apical targeting of renal ENaC subunits in puromycin aminonucleoside-induced nephrotic syndrome in rats. Am J Physiol Renal Physiol. 2004;286:F922-35 pubmed
    ..The decreased abundance of NHE3, BSC-1, TSC, and Na-K-ATPase may play a compensatory role to promote sodium excretion. ..
  30. Tiwari S, Packer R, Hu X, Sugimura Y, Verbalis J, Ecelbarger C. Increased renal alpha-ENaC and NCC abundance and elevated blood pressure are independent of hyperaldosteronism in vasopressin escape. Am J Physiol Renal Physiol. 2006;291:F49-57 pubmed
    ..Overall, the increase in aldosterone observed in vasopressin escape is not necessary for the increased expression of NCC, alpha- or gamma-ENaC or increased MAP associated with "escape." ..
  31. Huang D, Li T, He L. [Role of epithelial sodium channel alpha subunit in terbutaline-induced transient enhancement of pulmonary edema clearance in adult rats with acute lung injury]. Nan Fang Yi Ke Da Xue Xue Bao. 2009;29:868-71 pubmed
    To explore the association of epithelial sodium channel alpha subunit (alphaENaC) with terbutaline-induced transient enhancement of pulmonary edema clearance in adult rats with acute lung injury (ALI)...
  32. Borok Z, Liebler J, Lubman R, Foster M, Zhou B, Li X, et al. Na transport proteins are expressed by rat alveolar epithelial type I cells. Am J Physiol Lung Cell Mol Physiol. 2002;282:L599-608 pubmed
    ..These data demonstrate that AT1 cells express Na pump and Na channel proteins, supporting a role for AT1 cells in active transalveolar epithelial Na transport. ..
  33. Snyder P, McDonald F, Stokes J, Welsh M. Membrane topology of the amiloride-sensitive epithelial sodium channel. J Biol Chem. 1994;269:24379-83 pubmed
    ..Because of their sequence similarity, it is likely that this structure is shared by other ENaC subunits and possibly the degenerins of Caenorhabditis elegans as well. ..
  34. Staub O, Gautschi I, Ishikawa T, Breitschopf K, Ciechanover A, Schild L, et al. Regulation of stability and function of the epithelial Na+ channel (ENaC) by ubiquitination. EMBO J. 1997;16:6325-36 pubmed
    ..of ubiquitination and increased channel activity, an effect augmented by N-terminal Lys to Arg mutations in alpha ENaC, but not in beta ENaC...
  35. Hanwell D, Ishikawa T, Saleki R, Rotin D. Trafficking and cell surface stability of the epithelial Na+ channel expressed in epithelial Madin-Darby canine kidney cells. J Biol Chem. 2002;277:9772-9 pubmed
    ..Collectively, these results help elucidate key aspects of ENaC trafficking and turnover rates in mammalian kidney epithelial cells. ..
  36. Kienitz T, Allolio B, Strasburger C, Quinkler M. Sex-specific regulation of ENaC and androgen receptor in female rat kidney. Horm Metab Res. 2009;41:356-62 pubmed publisher
    ..Our data demonstrate that AR and ENaC are regulated by sex steroids. That way sex steroids might modulate renal sodium reabsorption and therefore provide a possible explanation for sex differences in blood pressure. ..
  37. Pearce L, Sommer E, Sakamoto K, Wullschleger S, Alessi D. Protor-1 is required for efficient mTORC2-mediated activation of SGK1 in the kidney. Biochem J. 2011;436:169-79 pubmed publisher
    ..Taken together, these results suggest that Protor-1 may play a role in enabling mTORC2 to efficiently activate SGK1, at least in the kidney. ..
  38. Muller O, Parnova R, Centeno G, Rossier B, Firsov D, Horisberger J. Mineralocorticoid effects in the kidney: correlation between alphaENaC, GILZ, and Sgk-1 mRNA expression and urinary excretion of Na+ and K+. J Am Soc Nephrol. 2003;14:1107-15 pubmed
  39. Enuka Y, Hanukoglu I, Edelheit O, Vaknine H, Hanukoglu A. Epithelial sodium channels (ENaC) are uniformly distributed on motile cilia in the oviduct and the respiratory airways. Histochem Cell Biol. 2012;137:339-53 pubmed publisher
    ..ENaC on motile cilia should be essential for diverse functions of motile cilia, such as germ cell transport, fertilization, implantation, clearance of respiratory airways and cell migration. ..
  40. Jernigan N, LaMarca B, Speed J, Galmiche L, Granger J, Drummond H. Dietary salt enhances benzamil-sensitive component of myogenic constriction in mesenteric arteries. Am J Physiol Heart Circ Physiol. 2008;294:H409-20 pubmed
    ..These data suggest that dietary sodium regulates ENaC expression and the quantitative importance of the vascular ENaC signaling pathway contributing to myogenic constriction. ..
  41. Rafii B, Gillie D, Sulowski C, Hannam V, Cheung T, Otulakowski G, et al. Pulmonary oedema fluid induces non-alpha-ENaC-dependent Na(+) transport and fluid absorption in the distal lung. J Physiol. 2002;544:537-48 pubmed
    ..Thus proteins or protein-dependent factors within cardiogenic EF induce an alpha-ENaC-independent and amiloride-insensitive apical membrane Na(+) conductance and liquid absorption in the distal lung. ..
  42. Xu J, Zong Y, Li X, Zhang Y, Li J. Divergent expression of α-ENaC in middle ear mucosa in the course of otitis media with effusion induced by barotrauma. Acta Otolaryngol. 2015;135:651-4 pubmed publisher
    ..Compared with the control, the volume of α-ENaC mRNA and protein increased significantly by 3.18-fold and 2.8-fold on the 3(rd) day, respectively, while decreased by 0.54-fold and 0.32-fold on the 7(th) day, respectively. ..
  43. Logvinenko N, Herbeck Y, Ivanova L. Investigation on genetic heterogeneity of ?-subunit of the epithelial sodium channel in rat renal cortex. Bull Exp Biol Med. 2011;151:709-12 pubmed
    ..It was found that mRNA deletion forms (a and b), products of alternative splicing of aENaC gene, are absent in the cortex of adult rat kidney. ..
  44. Greenlee M, Mitzelfelt J, Yu L, Yue Q, Duke B, Harrell C, et al. Estradiol activates epithelial sodium channels in rat alveolar cells through the G protein-coupled estrogen receptor. Am J Physiol Lung Cell Mol Physiol. 2013;305:L878-89 pubmed publisher
    ..The results presented herein implicate E2-mediated regulation of alveolar sodium channels in the sex differences observed in the pathogenesis of several pulmonary diseases. ..
  45. Zhang J, Zhuo X, Lin J, Luo L, Ying W, Xie X, et al. Maresin1 stimulates alveolar fluid clearance through the alveolar epithelial sodium channel Na,K-ATPase via the ALX/PI3K/Nedd4-2 pathway. Lab Invest. 2017;97:543-554 pubmed publisher
    ..Our findings reveal a novel mechanism for pulmonary edema fluid reabsorption and MaR1 may provide a new therapy for the resolution of ALI/ARDS. ..
  46. Frindt G, Ergonul Z, Palmer L. Surface expression of epithelial Na channel protein in rat kidney. J Gen Physiol. 2008;131:617-27 pubmed publisher
    ..Changes in the surface density of ENaC subunits contribute significantly to the regulation of Na transport in renal cells by mineralocorticoid hormone, but do not fully account for increased channel activity. ..
  47. Li T, Folkesson H. RNA interference for alpha-ENaC inhibits rat lung fluid absorption in vivo. Am J Physiol Lung Cell Mol Physiol. 2006;290:L649-L660 pubmed
    ..Thus we provide conclusive evidence that beta-adrenoceptor stimulation of lung fluid absorption is critically ENaC dependent, whereas baseline lung fluid absorption seemed less ENaC dependent. ..
  48. Lu L, Wu L, Chen J, Lin X, Wan C, Li Q. [Effects of sodium on rat osteoblast and the role of epithelial sodium channel]. Nan Fang Yi Ke Da Xue Xue Bao. 2011;31:1871-4 pubmed
  49. Dagenais A, Frechette R, Clermont M, Massé C, Privé A, Brochiero E, et al. Dexamethasone inhibits the action of TNF on ENaC expression and activity. Am J Physiol Lung Cell Mol Physiol. 2006;291:L1220-31 pubmed
    ..All these results suggest that dexamethasone alleviates the downregulation of ENaC expression and activity in TNF-treated alveolar epithelial cells. ..
  50. Yu Z, Schumacher M, Frey B, Frey F, Vogt B. Regulation of epithelial sodium channel in puromycin aminonucleoside-induced unilateral experimental nephrotic syndrome in normal and analbuminemic Nagase rats. Nephron Physiol. 2005;101:p51-62 pubmed
    ..ENaC mRNA and protein expression are not increased in the early phase of unilateral PAN-induced NS. Sgk1, Nedd4-2 and analbuminemia are not important regulatory factors of ENaC protein expression in experimental NS. ..
  51. Kelly O, Lin C, Ramkumar M, Saxena N, Kleyman T, Eaton D. Characterization of an amiloride binding region in the alpha-subunit of ENaC. Am J Physiol Renal Physiol. 2003;285:F1279-90 pubmed
    ..These data provide new insight into the relative position of the extracellular loop with respect to the pore of ENaC and its role in amiloride binding and channel gating. ..
  52. Planes C, Blot Chabaud M, Matthay M, Couette S, Uchida T, Clerici C. Hypoxia and beta 2-agonists regulate cell surface expression of the epithelial sodium channel in native alveolar epithelial cells. J Biol Chem. 2002;277:47318-24 pubmed
  53. Renard S, Lingueglia E, Voilley N, Lazdunski M, Barbry P. Biochemical analysis of the membrane topology of the amiloride-sensitive Na+ channel. J Biol Chem. 1994;269:12981-6 pubmed
    ..The well known regulation of the channel activity by hormones that activate this kinase such as vasopressin might thus be situated on another channel component. ..