Signaling by olfactory receptor neurons near threshold.
Ontology highlight
ABSTRACT:
SUBMITTER: Bhandawat V
PROVIDER: S-EPMC2972989 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:In vertebrates and some invertebrates, odorant molecules bind to G protein-coupled receptors on olfactory receptor neurons (ORNs) to initiate signal transduction. Phosphoinositide 3-kinase (PI3K) activity has been implicated physiologically in olfactory signal transduction, suggesting a potential role for a G protein-coupled receptor-activated class I PI3K. Using isoform-specific antibodies, we identified a protein in the olfactory signal transduction compartment of lobster ORNs that is antigenically similar to mammalian PI3Kgamma and cloned a gene for a PI3K with amino acid homology with PI3Kbeta. The lobster olfactory PI3K co-immunoprecipitates with the G protein alpha and beta subunits, and an odorant-evoked increase in phosphatidylinositol (3,4,5)-trisphosphate can be detected in the signal transduction compartment of the ORNs. PI3Kgamma and beta isoform-specific inhibitors reduce the odorant-evoked output of lobster ORNs in vivo. Collectively, these findings provide evidence that PI3K is indeed activated by odorant receptors in lobster ORNs and further support the potential involvement of G protein activated PI3K signaling in olfactory transduction.
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