Nuclear Localization and Interaction with COP1 Are Required for STO/BBX24 Function during Photomorphogenesis1[W]
Nuclear Localization and Interaction with COP1 Are Required for STO/BBX24 Function during Photomorphogenesis1[W]
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DOI：
10.1104/pp.111.180208
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发表时间：
2011-06
期刊：
影响因子：
7.4
通讯作者：
Huili Yan;K. Marquardt;M. Indorf;Dominic Jutt;S. Kircher;G. Neuhaus;M. Rodriguez-Franco
中科院分区：
文献类型：
--
作者：
Huili Yan;K. Marquardt;M. Indorf;Dominic Jutt;S. Kircher;G. Neuhaus;M. Rodriguez-Franco
拟南芥（Arabidopsis thaliana）耐盐性/B-BOX锌指蛋白24（STO/BBX 24）是光信号转导的负调控因子，定位于植物细胞核，在酵母（Saccharomycescerevisiae）双杂交系统中与组成型光形态发生蛋白1（COP 1）相互作用。该蛋白在N端含有两个B盒锌指基序，在C端含有一个保守基序，这是与COP 1相互作用所必需的。BBX 24在暴露于光的第一个小时的幼苗脱黄化期间积累。然而，这种积累是短暂的，并在长时间光照后减少。在这里，我们确定了蛋白质的核输入所必需的氨基酸残基。此外，我们创建了突变形式的蛋白质，并通过在bbx 24 -1突变体背景中过表达来分析它们。我们的研究结果表明，BBX 24的降解发生，或至少是在细胞核中启动，这种核定位是实现其光信号功能的先决条件。此外，负责与COP 1相互作用的区域中的突变揭示了蛋白质的物理相互作用也是BBX 24在光下降解和正常光形态建成所必需的。
Arabidopsis (Arabidopsis thaliana) SALT TOLERANCE/B-BOX ZINC FINGER PROTEIN24 (STO/BBX24) is a negative regulator of the light signal transduction that localizes to the nucleus of plant cells and interacts with CONSTITUTIVE PHOTOMORPHOGENIC1 (COP1) in the yeast (Saccharomyces cerevisiae) two-hybrid system. The protein contains two B-box zinc-finger motives at the N terminus and a conserved motif at the C-terminal part required for the interaction with COP1. BBX24 accumulates during deetiolation of young seedlings in the first hours of exposure to light. However, this accumulation is transient and decreases after prolonged light irradiation. Here, we identified the amino acidic residues necessary for the nuclear import of the protein. In addition, we created mutated forms of the protein, and analyzed them by overexpression in the bbx24-1 mutant background. Our results indicate that the degradation of BBX24 occurs, or at least is initiated in the nucleus, and this nuclear localization is a prerequisite to fulfill its function in light signaling. Moreover, mutations in the region responsible for the interaction with COP1 revealed that a physical interaction of the proteins is also required for degradation of BBX24 in the light and for normal photomorphogenesis.