Light-Activated Phytochrome A and B Interact with Members of the SPA Family to Promote Photomorphogenesis in Arabidopsis by Reorganizing the COP1/SPA Complex
Light-Activated Phytochrome A and B Interact with Members of the SPA Family to Promote Photomorphogenesis in Arabidopsis by Reorganizing the COP1/SPA Complex
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DOI：
10.1105/tpc.114.134775
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发表时间：
2015-01-01
期刊：
影响因子：
11.6
通讯作者：
Hiltbrunner, Andreas
中科院分区：
文献类型：
--
作者：
Sheerin, David J.;Menon, Chiara;Hiltbrunner, Andreas
光敏色素在植物中作为红色/远红色光受体发挥作用，并且对光调节生长和发育至关重要。光形态建成是种子植物在光照条件下的发育程序。在黑暗生长的幼苗中，光形态发生生长受到组成性光形态发生1（COP 1）/phyA-105（SPA）复合物的作用抑制，该复合物靶向光形态发生生长的正调节因子，用于被蛋白酶体降解。光敏色素抑制COP 1/SPA复合物，导致促进光形态建成的转录因子的积累;然而，它们抑制COP 1/SPA的机制仍然未知。在这里，我们表明，光激活光敏色素A（phyA）和光敏色素B（phyB）与SPA 1和其他SPA蛋白相互作用。荧光共振能量转移荧光寿命成像显微镜分析表明，SPAs和光敏色素共定位和相互作用的核体。此外，光激活的phyA和phyB破坏COP 1和SPA之间的相互作用，导致COP 1/SPA复合物在植物中的重组。光诱导的稳定HFR 1，光形态发生因子的目标降解COP 1/SPA，相关的时间与phyA在细胞核中的积累和本地化的phyA的核体。总的来说，这些数据提供了一个分子机制的COP 1/SPA复合物的phyA和phyB介导的光感知失活。
Phytochromes function as red/far-red photoreceptors in plants and are essential for light-regulated growth and development. Photomorphogenesis, the developmental program in light, is the default program in seed plants. In dark-grown seedlings, photomorphogenic growth is suppressed by the action of the CONSTITUTIVELY PHOTOMORPHOGENIC1 (COP1)/SUPPRESSOR OF phyA-105 (SPA) complex, which targets positive regulators of photomorphogenic growth for degradation by the proteasome. Phytochromes inhibit the COP1/SPA complex, leading to the accumulation of transcription factors promoting photomorphogenesis; yet, the mechanism by which they inactivate COP1/SPA is still unknown. Here, we show that light-activated phytochrome A (phyA) and phytochrome B (phyB) interact with SPA1 and other SPA proteins. Fluorescence resonance energy transfer-fluorescence lifetime imaging microscopy analyses show that SPAs and phytochromes colocalize and interact in nuclear bodies. Furthermore, light-activated phyA and phyB disrupt the interaction between COP1 and SPAs, resulting in reorganization of the COP1/SPA complex in planta. The light-induced stabilization of HFR1, a photomorphogenic factor targeted for degradation by COP1/SPA, correlates temporally with the accumulation of phyA in the nucleus and localization of phyA to nuclear bodies. Overall, these data provide a molecular mechanism for the inactivation of the COP1/SPA complex by phyA-and phyB-mediated light perception.