TRPgamma, a drosophila TRP-related subunit, forms a regulated cation channel with TRPL.
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.
Xu
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XZ
Department of Biological Chemistry and Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA.
Chien
F
F
Butler
A
A
Salkoff
L
L
Montell
C
C
D000595:Amino Acid Sequence / Q000235:genetics; D000818:Animals; D015220:Calcium Channels / Q000235:genetics / Q000502:physiology*; D002148:Calmodulin-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D002412:Cations / Q000378:metabolism*; D004330:Drosophila / Q000502:physiology; D029721:Drosophila Proteins; D004596:Electroretinography; D019476:Insect Proteins / Q000235:genetics / Q000502:physiology*; D007473:Ion Channels / Q000235:genetics / Q000378:metabolism* / Q000502:physiology*; D008027:Light; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D015388:Organelles / Q000378:metabolism; D017956:Photoreceptor Cells, Invertebrate / Q000378:metabolism; D020033:Protein Isoforms / Q000235:genetics / Q000502:physiology*; D012160:Retina / Q000528:radiation effects; D050051:Transient Receptor Potential Channels
D015220:Calcium Channels; D002148:Calmodulin-Binding Proteins; D002412:Cations; D029721:Drosophila Proteins; D019476:Insect Proteins; D007473:Ion Channels; D008565:Membrane Proteins; D020033:Protein Isoforms; C411581:TRPgamma protein, Drosophila; D050051:Transient Receptor Potential Channels; C063169:trp protein, Drosophila; C074192:trpl protein, Drosophila