Ggamma13 colocalizes with gustducin in taste receptor cells and mediates IP3 responses to bitter denatonium.

Gustducin is a transducin-like G protein selectively expressed in taste receptor cells. The alpha subunit of gustducin (alpha-gustducin) is critical for transduction of responses to bitter or sweet compounds. We identified a G-protein gamma subunit (Ggamma13) that colocalized with alpha-gustducin in taste receptor cells. Of 19 alpha-gustducin/Ggamma13-positive taste receptor cells ...
profiled, all expressed the G protein beta3 subunit (Gbeta3); approximately 80% also expressed Gbeta1. Gustducin heterotrimers (alpha-gustducin/Gbeta1/Ggamma13) were activated by taste cell membranes plus bitter denatonium. Antibodies against Ggamma13 blocked the denatonium-induced increase of inositol trisphosphate (IP3) in taste tissue. We conclude that gustducin heterotrimers transduce responses to bitter and sweet compounds via alpha-gustducin's regulation of phosphodiesterase (PDE) and Gbetagamma's activation of phospholipase C (PLC).
Mesh Terms:
Amino Acid Sequence, Animals, Cloning, Molecular, Enzyme Activation, Epithelial Cells, GTP-Binding Protein beta Subunits, GTP-Binding Protein gamma Subunits, GTP-Binding Proteins, Gene Expression Profiling, Heterotrimeric GTP-Binding Proteins, Humans, Inositol 1,4,5-Trisphosphate, Isoenzymes, Lingual Frenum, Mice, Mice, Transgenic, Molecular Sequence Data, Phospholipase C beta, Phosphoric Diester Hydrolases, Protein Binding, Quaternary Ammonium Compounds, RNA, Messenger, Sequence Alignment, Taste, Taste Buds, Transducin, Type C Phospholipases
Nat. Neurosci.
Date: Dec. 01, 1999
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