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Interregulation of proton-gated Na(+) channel 3 and cystic fibrosis transmembrane conductance regulator.
J Biol Chem 2006; 281(48):36960-8JB

Abstract

Proton-gated Na(+) channels (ASIC) are new members of the epithelial sodium channel/degenerin gene family. ASIC3 mRNA has been detected in the homogenate of pulmonary tissues. However, whether ASIC3 is expressed in the apical membranes of lung epithelial cells and whether it regulates cystic fibrosis transmembrane conductance regulator (CFTR) function are not known at the present time. Using reverse transcription-PCR, we found that the ASIC3 mRNA was expressed in the human airway mucosal gland (Calu-3) and human airway epithelial (16HBE14o) cells. Indirect immunofluorescence microscopy revealed that ASIC3 was co-segregated with CFTR in the apical membranes of Calu-3 cells. Proton-gated, amiloride-sensitive short circuit Na(+) currents were recorded across Calu-3 monolayers mounted in an Ussing chamber. In whole-cell patch clamp studies, activation of CFTR channels with cAMP reduced proton-gated Na(+) current in Calu-3 cells from -154 +/- 28 to -33 +/- 16 pA (n = 5, p < 0.05) at -100 mV. On the other hand, cAMP-activated CFTR activity was significantly inhibited following constitutive activation of putative ASIC3 at pH 6.0. Immunoassays showed that both ASIC3 and CFTR proteins were expressed and co-immunoprecipitated mutually in Calu-3 cells. Similar results were obtained in human embryonic kidney 293T cells following transient co-transfection of ASIC3 and CFTR. Our results indicate that putative CFTR and ASIC3 channels functionally interact with each other, possibly via an intermolecular association. Because acidic luminal fluid in the cystic fibrosis airway and lung tends to stimulate ASIC3 channel expression and activity, the interaction of ASIC3 and CFTR may contribute to defective salt and fluid transepithelial transport in the cystic fibrotic pulmonary system.

Authors+Show Affiliations

Department of Anesthesiology, University of Alabama at Birmingham, Birmingham, Alabama 35205, USA.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

17012229

Citation

Su, Xuefeng, et al. "Interregulation of Proton-gated Na(+) Channel 3 and Cystic Fibrosis Transmembrane Conductance Regulator." The Journal of Biological Chemistry, vol. 281, no. 48, 2006, pp. 36960-8.
Su X, Li Q, Shrestha K, et al. Interregulation of proton-gated Na(+) channel 3 and cystic fibrosis transmembrane conductance regulator. J Biol Chem. 2006;281(48):36960-8.
Su, X., Li, Q., Shrestha, K., Cormet-Boyaka, E., Chen, L., Smith, P. R., ... Ji, H. L. (2006). Interregulation of proton-gated Na(+) channel 3 and cystic fibrosis transmembrane conductance regulator. The Journal of Biological Chemistry, 281(48), pp. 36960-8.
Su X, et al. Interregulation of Proton-gated Na(+) Channel 3 and Cystic Fibrosis Transmembrane Conductance Regulator. J Biol Chem. 2006 Dec 1;281(48):36960-8. PubMed PMID: 17012229.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Interregulation of proton-gated Na(+) channel 3 and cystic fibrosis transmembrane conductance regulator. AU - Su,Xuefeng, AU - Li,Qingnan, AU - Shrestha,Kedar, AU - Cormet-Boyaka,Estelle, AU - Chen,Lan, AU - Smith,Peter R, AU - Sorscher,Eric J, AU - Benos,Dale J, AU - Matalon,Sadis, AU - Ji,Hong-Long, Y1 - 2006/09/29/ PY - 2006/10/3/pubmed PY - 2007/1/31/medline PY - 2006/10/3/entrez SP - 36960 EP - 8 JF - The Journal of biological chemistry JO - J. Biol. Chem. VL - 281 IS - 48 N2 - Proton-gated Na(+) channels (ASIC) are new members of the epithelial sodium channel/degenerin gene family. ASIC3 mRNA has been detected in the homogenate of pulmonary tissues. However, whether ASIC3 is expressed in the apical membranes of lung epithelial cells and whether it regulates cystic fibrosis transmembrane conductance regulator (CFTR) function are not known at the present time. Using reverse transcription-PCR, we found that the ASIC3 mRNA was expressed in the human airway mucosal gland (Calu-3) and human airway epithelial (16HBE14o) cells. Indirect immunofluorescence microscopy revealed that ASIC3 was co-segregated with CFTR in the apical membranes of Calu-3 cells. Proton-gated, amiloride-sensitive short circuit Na(+) currents were recorded across Calu-3 monolayers mounted in an Ussing chamber. In whole-cell patch clamp studies, activation of CFTR channels with cAMP reduced proton-gated Na(+) current in Calu-3 cells from -154 +/- 28 to -33 +/- 16 pA (n = 5, p < 0.05) at -100 mV. On the other hand, cAMP-activated CFTR activity was significantly inhibited following constitutive activation of putative ASIC3 at pH 6.0. Immunoassays showed that both ASIC3 and CFTR proteins were expressed and co-immunoprecipitated mutually in Calu-3 cells. Similar results were obtained in human embryonic kidney 293T cells following transient co-transfection of ASIC3 and CFTR. Our results indicate that putative CFTR and ASIC3 channels functionally interact with each other, possibly via an intermolecular association. Because acidic luminal fluid in the cystic fibrosis airway and lung tends to stimulate ASIC3 channel expression and activity, the interaction of ASIC3 and CFTR may contribute to defective salt and fluid transepithelial transport in the cystic fibrotic pulmonary system. SN - 0021-9258 UR - https://www.unboundmedicine.com/medline/citation/17012229/Interregulation_of_proton_gated_Na_+__channel_3_and_cystic_fibrosis_transmembrane_conductance_regulator_ L2 - http://www.jbc.org/cgi/pmidlookup?view=long&amp;pmid=17012229 DB - PRIME DP - Unbound Medicine ER -