Anti-OLFR73 polyclonal antibody

Background: Research on olfactory G-protein coupled receptors (GPCRs) has been severely impeded by poor functional expression in heterologous systems. Previously, we demonstrated that inefficient olfactory receptor (OR) expression at the plasma membrane is attributable, in part, to degradation of endoplasmic reticulum (ER)-retained ORs by the ubiquitin-proteasome system and sequestration of ORs in ER aggregates that are degraded by autophagy. Thus, experiments were performed to test the hypothesis that attenuation of ER degradation improves OR functional expression in heterologous cells. Results: To develop means to increase the functional expression of ORs, we devised an approach to measure activation of the mOREG OR (Unigene # Mm. 196680; Olfr73) through coupling to an olfactory cyclic nucleotide-gated cation channel (CNG). This system, which utilizes signal transduction machinery coupled to OR activation in native olfactory sensory neurons, was used to demonstrate that degradation, both by the ubiquitin-proteasome system and autophagy, limits mOREG functional expression. The stimulatory effects of proteasome and autophagy inhibitors on mOREG function required export from the ER and trafficking through the biosynthetic pathway. Conclusions: These findings demonstrate that poor functional expression of mOREG in heterologous cells is improved by blocking proteolysis. Inhibition of ER degradation may improve the function of other ORs and assist future efforts to elucidate the molecular basis of odor discrimination.

Gramine is an alkaloid found in giant reed and maple. Many reports discuss the health-beneficial effects of gramine in inflammation, angiogenesis, and cell growth. However, the physiological role of gramine in the odorant-induced signal transduction pathway has not yet been investigated. Therefore, in this study, we aimed to evaluate the effects of gramine on odorant-stimulated non-neuronal 3T3-L1 cells endogenously expressing the murine eugenol receptor, olfr73. We showed that gramine inhibited the eugenol-induced calcium influx and cyclic AMP (cAMP) elevation in the 3T3-L1 cells without any toxicity. In addition, gramine decreased the phosphorylation of protein kinase A and cAMP response element binding protein (CREB), which are known as downstream targets of cAMR in eugenol-stimulated 3T3-L1 cells. These results indicate that gramine suppresses the eugenol-induced signal transduction pathway in non-neuronal 3T3-L1 cells by modulating calcium influx, cAMP levels, and CREB phosphorylation.