Blue light-induced association of phototropin 2 with the Golgi apparatus
Blue light-induced association of phototropin 2 with the Golgi apparatus
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DOI：
10.1111/j.1365-313x.2006.02667.x
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发表时间：
2006-03-01
期刊：
影响因子：
7.2
通讯作者：
Nagatani, A
中科院分区：
文献类型：
--
作者：
Kong, SG;Suzuki, T;Nagatani, A
向光蛋白1和2（phot 1和phot 2）作为蓝光（BL）光感受器，在拟南芥向光性、叶绿体迁移、气孔开放和叶片扁平等过程中发挥重要作用。Phototropin由两个功能结构域组成，N-末端光敏结构域和C-末端Ser/Thr激酶结构域。然而，很少有人知道的信号转导途径，连接光感受器和生理反应下游的BL感知。为了了解phot 2启动这些反应的机制，我们转化了拟南芥的phot 1 phot 2双突变体，构建编码荧光融合phot 2：绿色荧光蛋白（P2 G）。在这些转基因植物中，P2 G对phot 2特异性生理反应具有完全功能。在黑暗中，它强烈定位于质膜，弱定位于细胞质。在用BL照射后，除了组成性质膜染色之外，在几分钟内形成点状P2 G染色。这种点状分布模式与高尔基体定位的KAM 1 Delta C：mRFP非常匹配。布雷菲德菌素A（BFA）是一种囊泡运输抑制剂，即使在黑暗中也能诱导P2 G在核周区域周围聚集，但未观察到点状模式。经BL处理后，P2 G呈点状分布，与高尔基体标记相匹配。因此，P2 G与高尔基体的光依赖性关联是不敏感的。结构/功能分析表明，激酶结构域是必不可少的高尔基体定位的光2。BL诱导的phot 2的高尔基体定位可能是phot 2信号转导途径中的重要信号步骤之一。
Phototropins 1 and 2 (phot1 and phot2) function as blue light (BL) photoreceptors for phototropism, chloroplast relocation, stomatal opening and leaf flattening in Arabidopsis thaliana. Phototropin consists of two functional domains, the N-terminal photosensory domain and the C-terminal Ser/Thr kinase domain. However, little is known about the signal transduction pathway that links the photoreceptors and the physiological responses downstream of BL perception. To understand the mechanisms by which phot2 initiates these responses, we transformed the phot1phot2 double mutant of Arabidopsis with constructs encoding translationally fused phot2: green fluorescent protein (P2G). P2G was fully functional for the phot2-specific physiological responses in these transgenic plants. It localized strongly to the plasma membrane and weakly to the cytoplasm in the dark. Upon illumination with BL, punctate P2G staining was formed within a few minutes in addition to the constitutive plasma membrane staining. This punctate distribution pattern matched well with that of the Golgi-localized KAM1 Delta C:mRFP. Brefeldin A (BFA), an inhibitor of vesicle trafficking, induced accumulation of P2G around the perinuclear region even in darkness, but the punctate pattern was not observed. After treatment of these cells with BL, P2G exhibited the punctate distribution pattern that matched with that of the Golgi marker. Hence, the light-dependent association of P2G with the Golgi apparatus was BFA-insensitive. A structure/function analysis indicated that the kinase domain was essential for the Golgi localization of phot2. The BL-induced Golgi localization of phot2 may be one of important signaling steps in the phot2 signal transduction pathway.