Under normal conditions the CFTR protein functions as a chloride channel pumping Cl- ions out of the cell. CFTR also functions as a regulator of other channels. When active, the NBF1 region of CFTR has an inhibitory effect on the epithelial sodium channel (ENaC).
Abnormal CF function. When non functioning CFTR is produvced or when no CFTR is produced the chloride ballance within cells is altered dramatically. ENaC is released from its inhibition and an increase in sodium conductance is observed. This leads to abnormal 'salty' cellular secretions which promotes bacterial colonisation of the lungs and ultimately to severe lung damage in CF patients