Olfactory and Vomeronasal Receptor Feedback Employ Divergent Mechanisms of PERK Activation

Mutually-exclusive chemoreceptor expression in olfactory and vomeronasal sensory neurons (OSNs and VSNs) enables odorant discrimination. This configuration involves chemoreceptor mediated activation of the endoplasmic reticulum (ER)-resident kinase PERK. PERK drives translation of the transcription factor ATF5 to preclude additional chemoreceptor expression. ATF5 translation is transient in OSNs but persistent in VSNs, suggesting chemoreceptor-specific modes of PERK activation. Herein, we showed that the ER-lumenal domain (LD) of PERK recognized vomeronasal receptor (VR)-derived peptides, suggesting direct PERK activation drives persistent ATF5 translation in VSNs. In contrast, PERK LD did not recognize olfactory receptor (OR)-derived peptides in vitro, and facilitating OR maturation in vivo prevented PERK activation, suggesting that ORs activate PERK indirectly through a failure to exit the ER. Importantly, impairing or prolonging ATF5 expression drove specific chemoreceptor repertoire biases. Together, these results demonstrate mechanistic divergence in chemoreceptor feedback and establish that differences in PERK activation promote qualitatively different gene regulatory results.