Fly cryptochrome and the visual system
Fly cryptochrome and the visual system
复制标题
DOI：
10.1073/pnas.1212317110
复制
发表时间：
2013-04-09
影响因子：
11.1
通讯作者：
Tosatto, Silvio C. E.
中科院分区：
文献类型：
--
作者：
Mazzotta, Gabriella;Rossi, Alessandro;Tosatto, Silvio C. E.
隐花色素是一种黄素蛋白，在结构和进化上与光解酶相关，参与多种生物的发育、磁感受和时间组织。果蝇光色素（dCRY）参与主生物钟的光同步化，其C末端在调节光敏感性和蛋白活性方面起重要作用。光激活dCRY需要构象变化，但已经表明激活也可以由结合蛋白质C末端的特定“调节剂”介导。该C-末端区域含有几个蛋白质-蛋白质相互作用基序，可能与信号转导调节相关。在这里，我们表明，一些功能性的线性图案是进化保守的隐花色素的C末端和III类PDZ结合位点选择性地保持在动物中。免疫共沉淀试验和质谱分析显示，dCRY与视网膜变性A（RDGA）和既不失活也不后电位C（NINAC）蛋白相互作用。这两种蛋白质都属于多蛋白复合物（Signalplex），其中包括视觉信号分子。利用生物信息学和分子生物学方法，发现dCRY与既不失活也不后电位C以光依赖的方式通过失活无后电位D（INAD）相互作用，并且dCRY-失活无后电位D相互作用由两种蛋白质的特定结构域介导，并且涉及CRY C末端。此外，在dCRY的果蝇突变体中观察到视觉行为的损害，这表明该感光体在果蝇视觉中的直接或间接作用。
Cryptochromes are flavoproteins, structurally and evolutionarily related to photolyases, that are involved in the development, magnetoreception, and temporal organization of a variety of organisms. Drosophila CRYPTOCHROME (dCRY) is involved in light synchronization of the master circadian clock, and its C terminus plays an important role in modulating light sensitivity and activity of the protein. The activation of dCRY by light requires a conformational change, but it has been suggested that activation could be mediated also by specific "regulators" that bind the C terminus of the protein. This C-terminal region harbors several protein-protein interaction motifs, likely relevant for signal transduction regulation. Here, we show that some functional linear motifs are evolutionarily conserved in the C terminus of cryptochromes and that class III PDZ-binding sites are selectively maintained in animals. A coimmunoprecipitation assay followed by mass spectrometry analysis revealed that dCRY interacts with Retinal Degeneration A (RDGA) and with Neither Inactivation Nor Afterpotential C (NINAC) proteins. Both proteins belong to a multiprotein complex (the Signalplex) that includes visual-signaling molecules. Using bioinformatic and molecular approaches, dCRY was found to interact with Neither Inactivation Nor Afterpotential C through Inactivation No Afterpotential D (INAD) in a light-dependent manner and that the CRY-Inactivation No Afterpotential D interaction is mediated by specific domains of the two proteins and involves the CRY C terminus. Moreover, an impairment of the visual behavior was observed in fly mutants for dCRY, indicative of a role, direct or indirect, for this photoreceptor in fly vision.