Plunc

Palate, lung, and nasal epithelium clone protein (PLUNC) is a gene encoding a secretory protein. It is also called Secretory protein in upper respiratory tracts (SPURT). In humans, it is encoded by the "BPIFA1" (Bactericidal/permeability-increasing fold-containing family A1) gene, previously called "PLUNC".
Function.
This gene is the human homolog of murine plunc, and like the mouse gene, is specifically expressed in the airways and nasopharyngeal regions. Plunc inhibits the epithelial sodium channel (ENaC), and also has anti-microbial functions. As such, plunc is believed to play a role in innate immune defense in the airways. PLUNC's ability to regulate ENaC is pH-sensitive and fails in acidic cystic fibrosis airways. Thus, defective PLUNC1 function is thought to contribute to the development of lung pathology in cystic fibrosis patients.
It may also serve as a potential molecular marker for detection of micrometastasis in non-small-cell lung cancer.