Molecular and electrophysiological characterization of nucleotide-sensitive chloride current-inducing protein of Fasciola hepatica

Nucleotide-sensitive chloride current regulating proteins (ICln's) of the chloride channels have been characterized from man and animals. An ICln of Fasciola hepatica (ICln-Fh) consisting of 231 amino acids revealed high similarities to both consensus domain of ICln's and two acidic residue-abundant patches in its C-terminus. Native ICln-Fh protein was confirmed present in F. hepatica soluble extract by immunoblotting. The recombinant ICln-Fh protein expressed in collagenase-defolliculated Xenopus oocytes induced fast rising and outward rectifying Cl− currents (ICln-Fh). The recombinant ICln-Fh protein, however, did not trigger cell swelling-induced Cl− currents (ICl-swell). The ICln-Fh currents were significantly reduced by substituting external Cl− with gluconic acid and by externally adding cAMP. Collectively, these results suggest that ICln-Fh protein is an inducer of Cl− currents in F. hepatica.