Evidence for direct CFTR inhibition by CFTRinh-172 based on arginine 347 mutagenesis

Emanuela Caci , Antonella Caputo , Alexandre Hinzpeter , Nicole Arous , Pascale Fanen , Nitin D Sonawane , Alan S Verkman , Roberto Ravazzolo , Olga Zegarra-Moran , Luis Jv Galietta (1)

1 Lab. of Molecular Genetics

The cystic fibrosis transmembrane conductance regulator (CFTR) is an epithelial Cl- channel inhibited with high affinity and selectivity by the thiazolidinone compound CFTRinh-172. Here, we present evidence that CFTRinh-172 acts directly on CFTR. We introduced mutations in amino acid residues of the sixth transmembrane helix of the CFTR protein, a domain that has an important role in the formation of the channel pore. Basic and hydrophilic amino acids at positions 334 – 352 were replaced with alanine and the sensitivity to CFTRinh-172 was assessed using functional assays. We found that arginine to alanine change at position 347 reduced by 20 – 30 fold the inhibitory potency of CFTRinh-172. Mutagenesis of arginine 347 to other amino acids also decreased inhibitory potency, with aspartate producing near total loss of CFTRinh-172 activity. Our results provide evidence that CFTRinh-172 interacts directly with CFTR, and that arginine 347 is important for the interaction.

Mots clés: Life Sciences

Emanuela Caci, Antonella Caputo, Alexandre Hinzpeter, Nicole Arous, Pascale Fanen, et al.. Evidence for direct CFTR inhibition by CFTRinh-172 based on arginine 347 mutagenesis. Biochemical Journal, 2008, 413 (1), pp.135-142. ⟨10.1042/BJ20080029⟩. ⟨hal-00478945⟩