Functional Expression of Chemoreceptors with the Help of a Guanine Nucleotide Exchange Factor
Odorant receptors and other chemoreceptors are usually poorly expressed in the plasma membrane of heterologous cells. A key point of regulation in G proteinmediated signaling is the interconversion between the active GTP-bound and inactive GDP-bound states of the G? subunit, which regulatory proteins, such as guanine nucleotide exchange factors (GEFs), can control. GEFs stimulate formation of the GTP-bound state of G? and therefore are considered to work as positive regulators of G proteincoupled receptor signaling. Ric-8B, a GEF that is specifically expressed in olfactory sensory neurons, promotes functional expression of odorant receptors in HEK293T cells because it amplifies the initially low receptor signaling through G?olf. This same strategy could be used to functionally express other types of chemoreceptors.
chemoreceptors guanine nucleotide exchange factors odorant receptors g?olf olfaction ric-8