Calnexin and Calreticulin are Involved in Chemosensory Behavior

Abstract

Calnexin and calreticulin are calcium binding proteins in the endoplasmic reticulum (ER) that act as molecular chaperones. They are involved in the proper assembly of proteins and play vital roles during signal transduction. In order to investigate the role of ER calcium binding proteins in experience-dependent behaviors, we studied the C. elegans homologs of both calnexin and calreticulin. Previously we showed that both, calnexin and calreticulin, are expressed in neurons, and both play an essential role during stress conditions. C. elegans is a soil nematode known to detect different volatile odorants using their chemosensory olfactory neurons. Prolonged exposure to an odorant, in wildtype animals, leads to diminished response to the odorant which we term adaptation. Mutants for calnexin, cnx-1, and calreticulin, crt-1, can respond robustly to odorants sensed by the AWC neurons such as isoamyl alcohol, benzaldehyde and butanone. The crt-1 animals exhibit hyperadaptation to AWC sensed odors when compared to wildtype, whereas, cnx-1 animals fail to adapt to these odors. These results suggest that CNX-1 may be involved in regulating olfactory adaptation. Currently, we are conducting odorant specific assays and investigating the olfaction mechanism responsible for experience-dependent behaviors involved in calnexin and calreticulin mutants.