Structural determinants for membrane trafficking and G protein selectivity of a mouse olfactory receptor

J Neurochem. 2004 Sep;90(6):1453-63. doi: 10.1111/j.1471-4159.2004.02619.x.


The G protein-coupled olfactory receptor (OR) superfamily plays a critical role in recognizing a broad range of odorants. Each OR appears to recognize odorants based on similarities in molecular structures such that mOR-EG, a mouse OR, binds eugenol, vanillin, and some other structurally related odorants. Only a few ORs, however, have been characterized functionally due to the difficulties in expressing ORs in heterologous cells. In this report, we demonstrate roles of the N- and C-terminal domains as key elements in the functional expression and signal transducing activity of an OR. Disruption of the N-terminal glycosylation site of the mOR-EG completely impaired its membrane trafficking to the cell surface. Functional expression of the mOR-EG was greatly enhanced by addition of extra N-terminal glycosylation sequences. Addition of a C-terminal epitope-tag or C-terminal truncation significantly reduced the odorant-response activity, although the receptors were properly targeted to the plasma membrane. Analysis of a series of truncated ORs revealed a region in the C-terminus that was crucial for the receptor activity. Replacement of the C-terminal portion of the mOR-EG with that of rhodopsin disrupted the coupling to G(alphas) but not to G(alpha15), demonstrating that the C-terminus is involved in regulating G protein specificity. These results suggest that glycosylation of the N-terminal portion is critical for OR expression and membrane trafficking, while the C-terminal portion plays a role in defining proper conformation, which, in turn, specifies the G protein selectivity of the OR. This information helps clarify the mechanisms that regulate membrane trafficking and G protein interaction of the OR superfamily.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Blotting, Western / methods
  • Calcium / metabolism
  • Carbachol / pharmacology
  • Cattle
  • Cell Line
  • Cyclic AMP / metabolism
  • Dose-Response Relationship, Drug
  • Embryo, Mammalian
  • Eugenol / pharmacology
  • Flow Cytometry / methods
  • GTP-Binding Proteins / metabolism*
  • Gene Expression Regulation / drug effects
  • Glycosylation
  • Humans
  • Immunohistochemistry / methods
  • Mice
  • Olfactory Receptor Neurons / drug effects
  • Olfactory Receptor Neurons / metabolism*
  • Precipitin Tests / methods
  • Protein Conformation
  • Protein Transport
  • Receptors, Odorant / genetics
  • Receptors, Odorant / metabolism*
  • Recombinant Fusion Proteins / metabolism*
  • Sensory Rhodopsins / metabolism
  • Sequence Alignment
  • Structure-Activity Relationship
  • Time Factors
  • Transfection / methods


  • Receptors, Odorant
  • Recombinant Fusion Proteins
  • Sensory Rhodopsins
  • Eugenol
  • Carbachol
  • Cyclic AMP
  • GTP-Binding Proteins
  • Calcium