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).
Huang
L
L
Howard Hughes Medical Institute, Mount Sinai School of Medicine of New York University, Box 1677, One Gustave L. Levy Place, New York, New York 10029, USA.
Shanker
Y G
YG
Dubauskaite
J
J
Zheng
J Z
JZ
Yan
W
W
Rosenzweig
S
S
Spielman
A I
AI
Max
M
M
Margolskee
R F
RF
D000595:Amino Acid Sequence; D000818:Animals; D003001:Cloning, Molecular; D004789:Enzyme Activation; D004847:Epithelial Cells / Q000737:chemistry; D044387:GTP-Binding Protein beta Subunits; D044388:GTP-Binding Protein gamma Subunits; D019204:GTP-Binding Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D020869:Gene Expression Profiling; D020962:Heterotrimeric GTP-Binding Proteins; D006801:Humans; D015544:Inositol 1,4,5-Trisphosphate / Q000378:metabolism*; D007527:Isoenzymes / Q000378:metabolism; D008035:Lingual Frenum; D051379:Mice; D008822:Mice, Transgenic; D008969:Molecular Sequence Data; D054799:Phospholipase C beta; D010727:Phosphoric Diester Hydrolases / Q000378:metabolism; D011485:Protein Binding; D000644:Quaternary Ammonium Compounds / Q000494:pharmacology*; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics; D016415:Sequence Alignment; D013649:Taste / Q000502:physiology*; D013650:Taste Buds / Q000737:chemistry* / Q000166:cytology / Q000201:enzymology / Q000378:metabolism; D015293:Transducin / Q000032:analysis / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010738:Type C Phospholipases / Q000378:metabolism
C118981:G-protein Beta gamma; D044387:GTP-Binding Protein beta Subunits; D044388:GTP-Binding Protein gamma Subunits; D007527:Isoenzymes; D000644:Quaternary Ammonium Compounds; D012333:RNA, Messenger; C075192:gustducin; D015544:Inositol 1,4,5-Trisphosphate; D010727:Phosphoric Diester Hydrolases; D010738:Type C Phospholipases; C518039:PLCB3 protein, human; D054799:Phospholipase C beta; C518040:Plcb3 protein, mouse; C518041:Plcb3 protein, rat; D019204:GTP-Binding Proteins; D020962:Heterotrimeric GTP-Binding Proteins; D015293:Transducin; C053525:denatonium saccharide