ERN1 and asthma: The protein sensors PERK, IRE-1α, and ATF6 respond to ER stress by increasing the expression of proteins such as binding immunoglobulin protein and CCAAT/enhancer-binding protein-homologous protein,37 which have been shown to be elevated in patients with asthma and in a murine model of neutrophilic, steroid-resistant AAD induced by LPS/ovalbumin.