Hardie Roger C
Department of Anatomy, Cambridge University, Downing Street, Cambridge CB2 3DY, UK.
Cell Calcium. 2003 May-Jun;33(5-6):385-93. doi: 10.1016/s0143-4160(03)00051-4.
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.
果蝇光感受器中的光敏电流由瞬时受体电位（TRP）通道介导，其中至少有两个成员（TRP和TRPL）在磷脂酶C（PLC）下游响应光而被激活。本文综述了最近的证据，表明果蝇TRP通道由PLC活性的一种或多种脂质产物激活：即二酰基甘油（DAG）、其代谢产物（多不饱和脂肪酸）或磷脂酰肌醇4,5-二磷酸（PIP(2)）的减少。这一观点最有说服力的证据来自对rdgA突变体的分析，由于DAG激酶缺陷，该突变体无法有效代谢DAG。rdgA突变导致TRP和TRPL通道的组成性激活，并在PLC和G蛋白的次等位基因突变中显著增加对光的敏感性。
