TRP channels in Drosophila photoreceptors: the lipid connection.
The light-sensitive current in Drosophila photoreceptors is mediated by transient receptor potential (TRP) channels, at least two members of which (TRP and TRPL) are activated downstream of phospholipase C (PLC) in response to light. Recent evidence is reviewed suggesting that Drosophila TRP channels are activated by one or more lipid products of PLC activity: namely diacylglycerol (DAG), its metabolites (polyunsaturated fatty acids) or the reduction in phosphatidylinositol 4,5-bisphosphate (PIP(2)). The most compelling evidence for this view comes from analysis of rdgA mutants which are unable to effectively metabolise DAG due to a defect in DAG kinase. The rdgA mutation leads to constitutive activation of both TRP and TRPL channels and dramatically increases sensitivity to light in hypomorphic mutations of PLC and G protein.
Hardie
Roger C
RC
Department of Anatomy, Cambridge University, Downing Street, Cambridge CB2 3DY, UK. rch14@hermes.cam.ac.uk
D000818:Animals; D015220:Calcium Channels / Q000502:physiology*; D019852:Diacylglycerol Kinase / Q000378:metabolism; D029721:Drosophila Proteins / Q000502:physiology*; D004331:Drosophila melanogaster / Q000378:metabolism; D050356:Lipid Metabolism; D009154:Mutation / Q000235:genetics; D017956:Photoreceptor Cells, Invertebrate / Q000378:metabolism*; D050051:Transient Receptor Potential Channels; D014785:Vision, Ocular / Q000502:physiology*
D015220:Calcium Channels; D029721:Drosophila Proteins; D050051:Transient Receptor Potential Channels; C063169:trp protein, Drosophila; D019852:Diacylglycerol Kinase