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Control of dynamic CFTR selectivity by glutamate and ATP in epithelial cells


Cystic fibrosis is caused by mutations in cystic fibrosis transmembrane conductance regulator (CFTR), an anion channel1. Phosphorylation and ATP hydrolysis are generally believed to be indispensable for activating CFTR2. Here we report phosphorylation- and ATP-independent activation of CFTR by cytoplasmic glutamate that exclusively elicits Cl-, but not HCO3-, conductance in the human sweat duct. We also report that the anion selectivity of glutamate-activated CFTR is not intrinsically fixed, but can undergo a dynamic shift to conduct HCO3- by a process involving ATP hydrolysis. Duct cells from patients with ΔF508 mutant CFTR showed no glutamate/ATP activated Cl- or HCO3- conductance. In contrast, duct cells from heterozygous patients with R117H/ΔF508 mutant CFTR also lost most of the Cl- conductance, yet retained significant HCO3- conductance. Hence, not only does glutamate control neuronal ion channels, as is well known, but it can also regulate anion conductance and selectivity of CFTR in native epithelial cells. The loss of this uniquely regulated HCO3- conductance is most probably responsible for the more severe forms of cystic fibrosis pathology.

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Figure 1: Effect of cytoplasmic glutamate on CFTR-gCl.
Figure 2: Effect of ATP on the HCO3- selectivity of glutamate-activated CFTR.
Figure 3: Effect of ATP and AMP-PNP on CFTR - g HCO 3 .
Figure 4: Effect of CFTR mutations on CFTR-gCl and CFTR - g HCO 3 .


  1. Quinton, P. M. Physiological basis of cystic fibrosis: A historic perspective. Physiol. Rev. 79, S3–S22 (1999)

    Article  CAS  Google Scholar 

  2. Anderson, M. P. et al. Nucleoside triphosphates are required to open the CFTR chloride channel. Cell 67, 775–784 (1991)

    Article  CAS  Google Scholar 

  3. Li, C. et al. ATPase activity of the cystic fibrosis transmembrane conductance regulator. J. Biol. Chem. 271, 28463–28468 (1996)

    Article  CAS  Google Scholar 

  4. Riordan, J. R. et al. Identification of the cystic fibrosis gene: Cloning and characterization of complementary DNA. Science 245, 1066–1072 (1989)

    Article  ADS  CAS  Google Scholar 

  5. Reddy, M. M. & Quinton, P. M. cAMP-independent phosphorylation activation of CFTR by G proteins in native human sweat duct. Am. J. Physiol. Cell Physiol. 280, C604–C613 (2001)

    Article  CAS  Google Scholar 

  6. Lew, T. S. & Krasne, S. The only anion-selective channel measured in intact sweat ducts has a unit conductance of 8 pS. Pediatr. Pulmonol. Suppl. 6, 251 (1991)

    Google Scholar 

  7. Duan, S. & Cooke, I. Glutamate and GABA activate different receptors and Cl- conductances in Crab peptide secretory neurons. J. Nephrophysiol. 83, 31–37 (2000)

    Article  CAS  Google Scholar 

  8. Cavalheiro, E. & Olney, J. Glutamate antagonists: Deadly liaisons with cancer. Proc. Natl Acad. Sci. USA 98, 5947–5948 (2001)

    Article  ADS  CAS  Google Scholar 

  9. Kartner, N., Augustinas, O., Jensen, T. J., Naismith, A. L. & Riordan, J. R. Mislocalization of ΔF508 CFTR in cystic fibrosis sweat gland. Nature Genet. 1, 321–327 (1992)

    Article  CAS  Google Scholar 

  10. Reddy, M. M. et al. Failure of the cystic fibrosis transmembrane conductance regulator to conduct ATP. Science 271, 1876–1879 (1996)

    Article  ADS  CAS  Google Scholar 

  11. Quinton, P. M. & Reddy, M. M. Control of CFTR Cl conductance by ATP levels through non-hydrolytic binding. Nature 360, 79–81 (1992)

    Article  ADS  CAS  Google Scholar 

  12. Welbourne, T. & Nissim, I. Regulation of mitochondrial glutamine/glutamate metabolism by glutamate transport:studies with 15N. Am. J. Physiol. Cell Physiol. 280, C1151–C1159 (2001)

    Article  CAS  Google Scholar 

  13. Raj, D., Langford, M., Krueger, S., Shelton, M. & Welbourne, T. Regulatory responses to an oral D-glutamate load: formation of D-pyrrolidone carboxylic acid in humans. Am. J. Physiol. Renal Physiol. 280, F214–F220 (2001)

    Article  Google Scholar 

  14. Dall'Asta, V. et al. Amino acids are compatible osmolytes for volume recovery after hypertonic shrinkage in vascular endothelial cells. Am. J. Physiol. C 276, C865–C872 (1999)

    Article  CAS  Google Scholar 

  15. Skerry, T. & Genever, P. Glutamate signaling in non-neuronal tissues. Trends Pharmacol. Sci. 22, 174–181 (2001)

    Article  CAS  Google Scholar 

  16. Conn, P. & Pin, J. Pharmacology and functions of metabotropic glutamate receptors. Annu. Rev. Physiol. 37, 205–237 (1997)

    CAS  Google Scholar 

  17. Wollheim, C. Beta-cell mitochondria in the regulation of insulin secretion: a new culprit in Type II diabetes. Diabetologia 43, 265–277 (2002)

    Article  Google Scholar 

  18. Santana, L. F., Gomez, A. M. & Lederer, W. J. Ca2+ flux through promiscuous cardiac Na+ channels: slip-mode conductance. Science 279, 1027–1033 (1998)

    Article  ADS  CAS  Google Scholar 

  19. Khakh, B. S. Molecular physiology of P2X receptors and ATP signalling at synapses. Nature Rev. Neurosci. 2, 165–174 (2001)

    Article  CAS  Google Scholar 

  20. Linsdell, P. & Hanrahan, J. W. Adenosine triphosphate dependent asymmetry of anion permeation in the cystic fibrosis transmembrane conductance regulator. J. Gen. Physiol. 111, 601–614 (1998)

    Article  CAS  Google Scholar 

  21. Gunderson, K. L. & Kopito, R. R. Conformational states of CFTR associated with channel gating: The role of ATP binding and hydrolysis. Cell 82, 231–239 (1995)

    Article  CAS  Google Scholar 

  22. Reddy, M. M., Light, M. J. & Quinton, P. M. Activation of the epithelial Na+ channel (ENaC) requires CFTR Cl- channel function. Nature 402, 301–304 (1999)

    Article  ADS  CAS  Google Scholar 

  23. Cheng, S. H. et al. Defective intracellular transport and processing of CFTR is the molecular basis of most cystic fibrosis. Cell 63, 827–834 (1990)

    Article  CAS  Google Scholar 

  24. Drumm, M. L. et al. Chloride conductance expressed by ΔF508 and other mutant CFTRs in Xenopus oocytes. Science 254, 1797–1799 (1991)

    Article  ADS  CAS  Google Scholar 

  25. Sheppard, D. N. et al. Mutations in CFTR associated with mild-disease-form Cl- channels with altered pore properties. Nature 362, 160–164 (1993)

    Article  ADS  CAS  Google Scholar 

  26. Durie, P. R. & Forstner, G. G. in Cystic Fibrosis in Adults (eds Yankaskas, J. R. & Knowles, M. R.) 261–287 (Lippincott-Raven, Philadelphia, 1999)

    Google Scholar 

  27. Sohma, Y., Gray, M. A., Imai, Y. & Argent, B. HCO3- transport in a mathematical model of the pancreatic ductal epithelium. J. Membr. Biol. 176, 77–100 (2000)

    CAS  PubMed  Google Scholar 

  28. Poulsen, J. H., Fischer, H., Illek, B. & Machen, T. E. Bicarbonate conductance and pH regulatory capability of cystic fibrosis transmembrane conductance regulator. Proc. Natl Acad. Sci. USA 91, 5340–5344 (1995)

    Article  ADS  Google Scholar 

  29. Choi, J. Y. et al. Aberrant CFTR-dependent HCO3- transport in mutations associated with cystic fibrosis. Nature 410, 94–97 (2001)

    Article  ADS  CAS  Google Scholar 

  30. Ko, S. B. H. et al. A molecular mechanism for aberrant CFTR-dependent HCO3- transport in cystic fibrosis. EMBO J. 21, 5662–5672 (2002)

    Article  CAS  Google Scholar 

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We thank K. Taylor and S. Madireddi for technical assistance, A. Ponce for reverse transcriptase polymerase chain reaction, and M. Pian, D. Conrad, C. Nagy, A. Wallace and M. Farrel for assistance in securing specimens from normal and cystic fibrosis patients. This work was funded by grants from the USPHS-NIH, the CF Foundation, the Olmsted Trust, the Gillette Co. and the Texaco Foundation.

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Correspondence to M. M. Reddy.

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Reddy, M., Quinton, P. Control of dynamic CFTR selectivity by glutamate and ATP in epithelial cells. Nature 423, 756–760 (2003).

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