Replacing the G-protein-coupling domains of the β2-adrenergic receptor with homologous domains of putative olfactory receptors produced chimeric receptors which were able to stimulate pigment dispersion in Xenopus melanophores, a G-protein-mediated pathway. A multiple replacement chimera containing the second, third and C-terminal cytoplasmic domains of receptor OR5 elevated cyclic adenosine 3':5'-monophosphate (cAMP) and suppressed production of inositol phosphates. Go-expression of Gα(olf) did not alter the strength of response of this chimera. A novel rat olfactory receptor cDNA (U131) was isolated and sequenced. Expression of U131 and OR5 constructs containing an N-terminal epitope-tag or C-terminal fusion to green fluorescent protein occurred in an intracellular network but not in the plasma membrane of heterologous cells. Similarly treated β2-adrenergic receptors were functional and were observed in the plasma membrane and the intracellular network. These results demonstrate that the putative cytoplasmic domains of olfactory receptors are capable of functional interaction with heterologous G-proteins of the Gα(s), subtype. Instead, the absence of these receptors from the plasma membrane of heterologous cells appears to explain our inability to determine if odorants can activate the olfactory receptor clones. We hypothesize that the olfactory receptors have requirements for maturation and targeting to the plasma membrane that are different from most other G-protein-coupled receptors.
|Number of pages||9|
|Journal||Molecular Brain Research|
|State||Published - Sep 1997|
Bibliographical noteFunding Information:
We thank Alison Roby-Shemkovitz, Greg Graf and Donghai Wu for technical assistance. Supported by Research Grant 1 R01 DC 02736 from the National Institute on Deafness and Other Communication Disorders, National Institutes of Health to T.S.M. and an Office of Naval Research Grant to M.R.L.
- Cyclic adenosine 3':5'-monophosphate
- Functional expression
- GTP-binding protein
- Molecular sequence data
- Olfactory receptor
- Signal transduction
ASJC Scopus subject areas
- Molecular Biology
- Cellular and Molecular Neuroscience