Editing Club cell (section)

==Clinical significance==
Club cells contain [[tryptase]], which is believed to be responsible for cleaving the [[hemagglutinin]] surface protein of [[influenza A]] virus, thereby activating it and causing the symptoms of flu.<ref name="pmid9707539">
{{cite journal |author=Taubenberger JK |title=Influenza virus hemagglutinin cleavage into HA1, HA2: No laughing matter |journal=Proc. Natl. Acad. Sci. U.S.A. |volume=95 |issue=17 |pages=9713–5 |date=August 1998 |pmid=9707539 |pmc=33880 |doi= 10.1073/pnas.95.17.9713|bibcode=1998PNAS...95.9713T |doi-access=free }}</ref> When the [[Chromosome 11 open reading frame 73|l7Rn6]] protein is disrupted in mice, these mice display severe [[emphysema]] at birth as a result of disorganization of the [[Golgi apparatus]] and formation of aberrant vesicular structures within club cells.<ref name="pmid16157679">
{{cite journal | vauthors = Fernández-Valdivia R, Zhang Y, Pai S, Metzker ML, Schumacher A | title = l7Rn6 Encodes a Novel Protein Required for Clara Cell Function in Mouse Lung Development | journal = Genetics | volume = 172 | issue = 1 | pages = 389–99 |date=January 2006 | pmid = 16157679 | pmc = 1456166 | doi = 10.1534/genetics.105.048736 }}</ref>
Malignant club cells are also seen in bronchioalveolar carcinoma of the lung.
Serum club cell proteins are used as a biomarker of lung permeability.  Exposure to particulate air pollution may compromise the integrity of the lung epithelium and lead to rapid increase in epithelial barrier permeability, as reflected by increased serum club cell concentrations.<ref>Provost EB, Chaumont A, Kicinski M, Cox B, Fierens F, Bernard A, Nawrot TS. “Serum levels of club cell secretory protein (Clara) and short- and long-term exposure to particulate air pollution in adolescents” Environ Int. 2014 Apr 4;68C:66-70. doi: 10.1016/j.envint.2014.03.011.</ref>