Connexins in the Respiratory Epithelium

The respiratory epithelium is positioned at the interface between the body and the environment. This highly differentiated epithelium plays a crucial role in maintaining the sterility of pulmonary tissues by orchestrating mechanical, innate, and acquired host defense systems. The functional integrity of the airway epithelium depends on expression and assembly of specific proteins into specialized junctional structures. The profile of connexin expression changes dramatically during organogenesis, and shortly after birth. Surprisingly, there is little information on the role of gap junctions and their constituent proteins, connexins, in the adult respiratory epithelium. Although it has been assumed that gap junctions are rare in the air-conducting and respiratory epithelia, recent data point to the roles of connexin channels in lung function and pathology.