Recently, DMNBS was used to controlphosphorylationat sites in cystic fibrosis transmembrane conductance regulator (CFTR),a protein which causes cystic fibrosis when mutated.119,387 CFTR is a transepithelial channel responsible for regulating Cl– flow and plays important roles in fluid and electrolytesecretion, sweat gland and airway epithelia, and electrolyte absorption.388 Phosphorylation of CFTR occurs at multiplesites, making it difficult to discern their individual consequenceson activity. This evidence concerns the gene CFTR and cystic fibrosis.