The GRP94/LMAN1-MCFD2 axis controls secretion of chemosensory proteins and enables a carboxylesterase complex in Nilaparvata lugens.

Despite their crucial roles in insect olfaction and insecticide resistance, the functional diversity of chemosensory proteins (CSPs) remains largely underexplored due to challenges in their characterization. Leveraging the protein interactome for the functional characterization of CSPs may represent a feasible approach. An interactome approach was utilized to elucidate the function of NlCSP1 in Nilaparvata lugens. We identified a GRP94/LMAN1-MCFD2 axis that governs the folding and secretion of NlCSP1. NlGRP94 and NlGRP78 act as chaperones, and NlLMAN1-NlMCFD2 complex controls its endoplasmic reticulum (ER) to Golgi apparatus (GA) trafficking. Furthermore, the secretion of CSPs and odorant-binding proteins (OBPs) in insects may be broadly regulated by the GRP94/LMAN1-MCFD2 axis. In addition to secretion, NlCSP1 directly interacts with the carboxylesterase NlCarE6-1, forming a complex that may enhance ligand-binding affinity and associates with lipid-like molecules. These results reveal a previously unrecognized regulatory axis, the GRP94/LMAN1-MCFD2 pathway, which maintains the homeostasis of CSPs/OBPs. Moreover, the CSP-carboxylesterase complex may represent a novel mechanism contributing to odorant degradation and insecticide resistance, pending in vivo functional validation. These findings highlight the potential for targeting secretion via this axis or disrupting the CSP- carboxylesterase complex as a strategy for species-specific pest management. © 2026 Society of Chemical Industry.