Ubiquitination-driven down-regulation of the cell adhesion molecule Na,K-ATPase β-subunit by hypercapnia in alveolar epithelial cells

Acute lung injury (ALI) is associated with alveolo-capillary barrier dysfunction leading to impaired gas exchange and thus elevated CO2 levels (hypercapnia). In addition to the well-studied role of the α-subunit of the Na,K-ATPase in alveolar edema fluid clearance during ALI, the Na,K-ATPase β-subunit located at the sites of cell-cell junction acts as a cell adhesion molecule and therefore might be an important player in the alveolar-capillary barrier repair. Here, we studied the effects of hypercapnia on the stability of Na,K-ATPase β-subunit and on cell junction formation. Exposing human alveolar epithelial A5…