Abstract
The sodium bicarbonate cotransporter (NBC1) mediates bicarbonate reabsorption in the renal proximal tubule. NBC1 activity is stimulated by 10% CO2, however, the mechanism is poorly understood. Here, we examined the mechanism of NBC1 regulation by 10% CO2 using an immortalized human proximal tubule cell line (HK2). In cells exposed to 10% CO2, the cotransporter activity (measured as ΔpH/min) increased within minutes and this increase was maintained for 6 to 24 h. Early NBC1 stimulation was accompanied by increased NBC1 phosphorylation. Basolateral membrane NBC1 protein increased by 30 min and reached a maximum at 6 h. Increased NBC activity at 6 h was accounted for by increased NBC exocytosis to the basolateral membrane and not by decreased endocytosis. Latruncullin B (an actin cytoskeleton inhibitor) did not prevent CO2-induced stimulation, while nocodazole (a microtubule-disrupting agent) abrogated the stimulatory effect of 10% CO2. A significant increase in NBC1 mRNA expression level was observed at 6 h and maintained for 24 h. Total NBC1 protein increased at 12 to 24 h with 10% CO2 incubation and this effect was blocked by cycloheximide. In summary, the present study demonstrates that early activation of NBC1 activity by 10% CO2 was mediated by NBC1 phosphorylation. The stimulation of cotransporter activity observed at 6 h was due to exocytosis, while the late effect starting from 12 h was accounted for by increased protein synthesis.
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References
H.J. Adrogue N.E. Madias (1986) ArticleTitleRenal acidification during chronic hypercapnia in the conscious dog Pfluegers Arch 406 520–528 Occurrence Handle10.1007/BF00583376
M. Amemiya Y. Yamaji A. Cano O.W. Moe R.J. Alpern (1995) ArticleTitleAcid incubation increases NHE-3 mRNA abundance in OKP cells Am. J. Physiol 269 C126–C133 Occurrence Handle7631739
A.A, E.D. Bernardo O.S. Ruiz R.B. Robey J.A. Arruda (2003) ArticleTitleThe role of phosphatidylinositol 3-kinase (PI3K) in CO2 stimulation of the Na+/HCO −3 cotransporter (NBC) J. Membrane Biol 191 141–148 Occurrence Handle10.1007/s00232-002-1051-3
W.F. Boron E.L. Boulpaep (1983) ArticleTitleIntracellular pH regulation in the renal proximal tubule of the salamander. Basolateral HCO3− transport J. Gen. Physiol 81 53–94 Occurrence Handle10.1085/jgp.81.1.53 Occurrence Handle6833997
P. Brazeau A. Gilman (1953) ArticleTitleEffect of plasma CO2 tension on renal tubular reabsorption of bicarbonate Am. J. Physiol 175 33–38 Occurrence Handle13114345
D. Brown J.L. Stow (1996) ArticleTitleProtein trafficking and polarity in kidney epithelium: from cell biology to physiology Physiol. Rev 76 245–297 Occurrence Handle8592730
C.E. Burnham H. Amlal Z.H. Wang G.E. Shull M. Soleimani (1997) ArticleTitleCloning and functional expression of a human kidney Na+:HCO −3 cotransporter J. Biol. Chem 272 19111–19114 Occurrence Handle10.1074/jbc.272.31.19111 Occurrence Handle9235899
H.F. Cantiello J.L. Stow A.G. Prat D.A. Ausiello (1991) ArticleTitleActin filaments regulate epithelial Na+ channel activity Am. J. Physiol 261 C882–C888 Occurrence Handle1659214
L.K. Chen W.F. Boron (1995) ArticleTitleAcid extrusion in S3 segment of rabbit proximal tubule. I. Effect of bilateral CO2/HCO3 Am. J. Physiol 268 F179–F192 Occurrence Handle7864155
P.J. Dorman W.J. Sullivan R.F. Pitts (1954) ArticleTitleThe renal response to acute respiratory acidosis J. Clin. Invest 33 82–90 Occurrence Handle13117969
A.M. Edelman D.K. Blumenthal E.G. Krebs (1987) ArticleTitleProtein serine/threonine kinases Annu. Rev. Biochem 56 567–613 Occurrence Handle2956925
D.J. Espiritu A.A. Bernardo R.B. Robey J.A. Arruda (2002) ArticleTitleA central role for Pyk2-Src interaction in coupling diverse stimuli to increased epithelial NBC activity Am. J. Physiol 283 F663–F670
O.A. Noboa D.J.D. Espiritu A.A. Bernardo J.A.L. Arruda (2001) ArticleTitleMicrotubules play a role in stimulation of Na+/HCO −3 (NBC1) activity by angiotensin II (AII) J. Am. Soc. Nephrol. 12 59A Occurrence Handle10.1159/000047682
O.A. Noboa D.J.D. Espiritu A.A. Bernardo J.A.L. Arruda (2000) ArticleTitleAngiotensin II modulates Na+/HCO −3 cotransporter (NBC) in cultured human proximal tubule cells through novel mechanism J. Am. Soc. Nephrol. 11 7A
R.B. Robey O.S. Ruiz D.J. Espiritu V.C. Ibanez F.T. Kear O.A. Noboa A.A. Bernardo J.A. Arruda (2002) ArticleTitleAngiotensin II stimulation of renal epithelial cell Na/HCO3 cotransport activity: A central role for Src family kinase/classic MAPK pathway coupling J. Membrane Biol 187 135–145 Occurrence Handle10.1007/s00232-001-0157-3
M.F. Romero M.A. Hediger E.L. Boulpaep W.F. Boron (1997) ArticleTitleExpression cloning and characterization of a renal electrogenic Na+/HCO3− cotransporter Nature 387 409–413 Occurrence Handle10.1038/387409a0 Occurrence Handle9163427
O.S. Ruiz J.A. Arruda Z. Talor (1989) ArticleTitleNa-HCO3 cotransport and Na-H antiporter in chronic respiratory acidosis and alkalosis Am. J. Physiol 256 F414–F420 Occurrence Handle2564256
O.S. Ruiz Y.Y. Qiu L.R. Cardoso J.A. Arruda (1998a) ArticleTitleRegulation of the renal Na-HCO3 cotransporter: IX. Modulation by insulin, epidermal growth factor and carbachol Regul. Pept 77 155–161 Occurrence Handle10.1016/S0167-0115(98)00115-3
O.S. Ruiz Y.Y. Qiu L.J. Wang L.R. Cardoso J.A. Arruda (1998b) ArticleTitleRegulation of renal Na-HCO3 cotransporter: VIII. Mechanism of stimulatory effect of respiratory acidosis J. Membrane. Biol 162 201–208 Occurrence Handle10.1007/s002329900357
O.S. Ruiz R.B. Robey Y.Y. Qiu L.J. Wang C.J. Li J. Ma J.A. Arruda (1999) ArticleTitleRegulation of the renal Na-HCO3 cotransporter. XI. Signal transduction underlying CO2 stimulation Am. J. Physiol 277 F580–F586 Occurrence Handle10516283
O.S. Ruiz L.J. Wang P. Pahlavan J.A. Arruda (1995) ArticleTitleRegulation of renal Na-HCO3 cotransporter: III Presence and modulation by glucocorticoids in primary cultures of the proximal tubule Kidney Int 47 1669–1676 Occurrence Handle7643535
M. Sargiacomo M. Lisanti L Graeve A. Le Bivic E. Rodriquez-Boulan (1989) ArticleTitleIntegral and protein composition of the apical and basolateral membrane domains in MDCK cells J. Membrane Biol 107 277–286 Occurrence Handle10.1007/BF01871942
A. Sengupta W.K. Liu Y.G. Yeung D.C. Yeung A.R. Frackelton SuffixJr E.R. Stanley (1988) ArticleTitleIdentification and subcellular localization of proteins that are rapidly phosphorylated in tyrosine in response to colony-stimulating factor 1 Proc Natl Acad Sci USA 85 8062–8066 Occurrence Handle2460861
E.J. Weinman C.M. Evangelista D. Steplock M.Z. Liu S. Shenolikar A. Bernardo (2001) ArticleTitleEssential role for NHERF in cAMP-mediated inhibition of the Na+-HCO −3 co-transporter in BSC-1 cells J. Biol. Chem 276 42339–42346 Occurrence Handle10.1074/jbc.M106153200 Occurrence Handle11535598
X. Yang M. Amemiya Y. Peng O.W. Moe P.A. Preisig R.J. Alpern (2000) ArticleTitleAcid incubation causes exocytic insertion of NHE3 in OKP cells Am. J. Physiol 279 C410–C419
Acknowledgements
The authors acknowledge the technical assistance of Fely Kear. This work was supported by the Merit Review Program Awards to Jose A.L. Arruda from the Department of Veterans Affairs.
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Espiritu, D., Yang, V., Bernardo, A. et al. Regulation of Renal Na+/HCO −3 Cotransporter Stimulation by CO2: Role of Phosphorylation, Exocytosis and Protein Synthesis. J Membrane Biol 199, 39–49 (2004). https://doi.org/10.1007/s00232-004-0675-x
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DOI: https://doi.org/10.1007/s00232-004-0675-x