For example, we previously showed that allergen (OVA) sensitization and chronic allergen challenge leads to a significant reduction in whole lung expression of total βARs (from 1004 ± 54 fmol/mg to 598 ± 88 fmol/mg) [15] and an elevation in whole lung expression of β-arrestin-2 (under second review Chen et al., Am J Respir Cell Mol Biol—“Genetic deletion of β-arrestin-2 mitigates established airway hyperresponsiveness in a murine asthma model”). This evidence concerns the gene CTBP1 and airway hyperresponsiveness.