Abstract
We used differential screening of cDNAs from individual taste receptor cells to identify candidate taste transduction elements in mice. Among the differentially expressed clones, one encoded Trpm5, a member of the mammalian family of transient receptor potential (TRP) channels. We found Trpm5 to be expressed in a restricted manner, with particularly high levels in taste tissue. In taste cells, Trpm5 was coexpressed with taste-signaling molecules such as alpha-gustducin, Ggamma13, phospholipase C-beta2 (PLC-beta2) and inositol 1,4,5-trisphosphate receptor type III (IP3R3). Our heterologous expression studies of Trpm5 indicate that it functions as a cationic channel that is gated when internal calcium stores are depleted. Trpm5 may be responsible for capacitative calcium entry in taste receptor cells that respond to bitter and/or sweet compounds.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Animals
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CHO Cells
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Calcium / metabolism
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Calcium Channels / genetics*
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Calcium Channels / metabolism*
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Cloning, Molecular
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Cricetinae
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Gene Expression
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Inositol 1,4,5-Trisphosphate Receptors
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Isoenzymes / metabolism
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Membrane Proteins / genetics*
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Membrane Proteins / metabolism*
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Mice
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Oocytes / physiology
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Phospholipase C beta
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RNA, Messenger / analysis
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Receptors, Cytoplasmic and Nuclear / metabolism
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TRPM Cation Channels
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Taste / physiology*
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Taste Buds / physiology*
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Transducin / genetics
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Type C Phospholipases / metabolism
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Xenopus laevis
Substances
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Calcium Channels
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Inositol 1,4,5-Trisphosphate Receptors
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Isoenzymes
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Membrane Proteins
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RNA, Messenger
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Receptors, Cytoplasmic and Nuclear
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TRPM Cation Channels
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Trpm5 protein, mouse
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gustducin
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Type C Phospholipases
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Phospholipase C beta
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Plcb2 protein, mouse
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Plcb2 protein, rat
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Transducin
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Calcium