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Inhibition of Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) by Influenza M2 Proton Channel
Author(s) -
Londino James David,
Atkins Colm,
Lazrak Ahmed,
Noah James,
Matalon Sadis
Publication year - 2011
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.25.1_supplement.1042.19
Subject(s) - cystic fibrosis transmembrane conductance regulator , epithelial sodium channel , amiloride , chemistry , cystic fibrosis , western blot , ion channel , patch clamp , microbiology and biotechnology , voltage clamp , pharmacology , biophysics , membrane potential , biology , medicine , sodium , biochemistry , receptor , gene , organic chemistry
Lung ion channels are essential for keeping the lung clear of inhaled particles and pathogens by regulation of airway surface liquid. Influenza M2 protein forms a pH activated, homotetramer proton channel that inhibits the expression and the activity of the amiloride sensitive sodium channel (ENaC) (Lazrak et al. 2009 FASEB J. 2009 Nov;23(11):3829–42). In order to determine the effect of Influenza M2 on fluid regulation it is necessary to understand how it affects other important ion channels. CFTR is an ABC ion transporter that regulates fluid balance in the lung as well as performing many other vital functions. Xenopus oocytes were co‐injected with human CFTR (0.25–0.5ng) and Udorn strain M2 (25ng) cRNAs and allowed to express for 72 hours. Whole cell currents were recorded using the two electrode voltage clamp technique. Forskolin activated current was inhibited with GlyH‐101 while M2 current was inhibited with Amantadine. Protein concentration was measured via Western Blot. Co‐expression of Influenza M2 and CFTR decreased CFTR current and protein expression. Inhibition was seen at 24 hours post M2 injection and continued at least to 72 hours. The decrease was not caused by translational competition as co‐expression of CFTR with Influenza M1 protein had no effect. Suppression was independent of ion channel activity as an inactive mutant (M2‐G34V) also decreased CFTR current. Funding provided by NIHR01‐ HL031197