Abstract
TRP and TRPL are two light-sensitive cation channel subunits required for the Drosophila photoresponse; however, our understanding of the identities, subunit composition, and function of the light-responsive channels is incomplete. To explain the residual photoresponse that remains in the trp mutant, a third TRP-related subunit has previously been proposed to function with TRPL. Here, we identify such a subunit, TRPgamma. We show that TRPgamma is highly enriched in photoreceptor cells and preferentially heteromultimerizes with TRPL in vitro and in vivo. The N-terminal domain of TRPgamma dominantly suppressed the TRPL-dependent photoresponse, indicating that TRPgamma-TRPL heteromultimers contribute to the photoresponse. While TRPL and TRPgamma homomultimers are constitutively active, we demonstrate that TRPL-TRPgamma heteromultimers form a regulated phospholipase C- (PLC-) stimulated channel.
Publication types
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Amino Acid Sequence / genetics
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Animals
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Calcium Channels / genetics
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Calcium Channels / physiology*
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Calmodulin-Binding Proteins / genetics
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Calmodulin-Binding Proteins / metabolism*
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Cations / metabolism*
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Drosophila / physiology
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Drosophila Proteins*
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Electroretinography
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Insect Proteins / genetics
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Insect Proteins / physiology*
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Ion Channels / genetics
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Ion Channels / metabolism*
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Ion Channels / physiology*
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Light
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Membrane Proteins / genetics
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Membrane Proteins / metabolism*
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Molecular Sequence Data
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Organelles / metabolism
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Photoreceptor Cells, Invertebrate / metabolism
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Protein Isoforms / genetics
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Protein Isoforms / physiology*
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Retina / radiation effects
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Transient Receptor Potential Channels
Substances
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Calcium Channels
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Calmodulin-Binding Proteins
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Cations
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Drosophila Proteins
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Insect Proteins
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Ion Channels
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Membrane Proteins
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Protein Isoforms
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TRPgamma protein, Drosophila
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Transient Receptor Potential Channels
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trp protein, Drosophila
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trpl protein, Drosophila
Associated data
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GENBANK/AJ277967
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GENBANK/AJ277968