The Coxsackievirus and Adenovirus Receptor Has a Short Half-Life in Epithelial Cells

The coxsackievirus and adenovirus receptor (CAR) is an essential cellular protein that is involved in cell adhesion, cell signaling, and viral infection. The 8-exon encoded isoform (CAR^Ex8) resides at the apical surface of polarized epithelia, where it is accessible as a receptor for adenovirus entering the airway lumen. Given its pivotal role in viral infection, it is a target for antiviral strategies. To understand the regulation of CAR^Ex8 and determine the feasibility of receptor downregulation, the half-life of total and apical localized CAR^Ex8 was determined and correlated with adenovirus transduction. Total and apical CAR^Ex8 has a relatively short half-life of approximately 2 h. The half-life of apical CAR^Ex8 correlates well with adenovirus transduction. These results suggest that antiviral strategies that aim to degrade the primary receptor for apical adenovirus infection will be effective within a relatively short time frame after application.