Localization of G14 and G-gustducin in type II taste cells. TrpM5 is a cation channel of the TRP superfamily that is highly expressed in taste buds of the tongue. In vallate and foliate taste buds of transgenic mice expressing TrpM5-GFP (green), two G-protein alpha subunits, G14 (red) and G-gustducin (blue), exist within the population of type II taste cells that express TrpM5. The red G14 staining that is present in sweet-sensitive taste cells outlines the reactive cells, showing that it is membrane-associated
Gustducin is a G protein associated with taste and the gustatory system, found in some taste receptor cells.
Research on the discovery and isolation of gustducin is recent. It is known to play a large role in the transduction of bitter, sweet and umami stimuli. Its pathways (especially for detecting bitter stimuli) are many and diverse.
An intriguing feature of gustducin is its similarity to transducin. These two G proteins have been shown to be structurally and functionally similar, leading researchers to believe that the sense of taste evolved in a similar fashion to the sense of sight.
Gustducin is a heterotrimeric protein composed of the products of the GNAT3 (α-subunit), GNB1 (β-subunit) and GNG13 (γ-subunit).
