Kong Xiangxiang, Ma Lan, Yang Liming, Chen Qian, Xiang Nan, Yang Yongping, Hu Xiangyang
Key Laboratory for Plant Diversity and Biogeography of East Asia, ‡Plant Germplasm and Genomics Center, the Germplasm Bank of Wild Species, and §Institute of Tibetan Plateau Research at Kunming, Kunming Institute of Botany, Chinese Academy of Science , No. 132 Lanhei Road, Heilongtan, Kunming 650204, China.
J Proteome Res. 2014 May 2;13(5):2495-510. doi: 10.1021/pr4012624. Epub 2014 Apr 11.
The cap-binding proteins CBP20 and CBP80 have well-established roles in RNA metabolism and plant growth and development. Although these proteins are thought to be involved in the plant's response to environmental stress, their functions in this process are unclear. Here we demonstrated that Arabidopsis cbp20 and cbp80 null mutants had abnormal leaves and flowers and exhibited increased sensitivity to salt stress. The aberrant phenotypes were more pronounced in the cbp20/80 double mutant. Quantification by iTRAQ (isobaric tags for relative and absolute quantification) identified 77 differentially expressed proteins in the cbp20 and cbp80 lines compared with the wild-type Col-0 under salt stress conditions. Most of these differentially expressed proteins were synergistically expressed in cbp20 and cbp80, suggesting that CBP20 and CBP80 have synergistic roles during the salt stress response. Biochemical analysis demonstrated that CBP20 and CBP80 physically interacted with each other. Further analysis revealed that CBP20/80 regulated the splicing of genes involved in proline and sugar metabolism and that the epigenetic and post-translational modifications of these genes were involved in salt stress tolerance. Our data suggest a link between CBP20/80-dependent protein ubiquitination/sumoylation and the salt stress response.
帽结合蛋白CBP20和CBP80在RNA代谢以及植物生长发育过程中具有已明确的作用。尽管这些蛋白被认为参与植物对环境胁迫的响应，但其在此过程中的功能尚不清楚。在此，我们证明拟南芥cbp20和cbp80缺失突变体具有异常的叶片和花朵，并且对盐胁迫表现出更高的敏感性。在cbp20/80双突变体中，异常表型更为明显。通过iTRAQ（相对和绝对定量的等压标签）定量分析发现，在盐胁迫条件下，与野生型Col-0相比，cbp20和cbp80株系中有77种差异表达蛋白。这些差异表达蛋白中的大多数在cbp20和cbp80中协同表达，表明CBP20和CBP80在盐胁迫响应过程中具有协同作用。生化分析表明，CBP20和CBP80相互之间存在物理相互作用。进一步分析发现，CBP20/80调控参与脯氨酸和糖代谢的基因的剪接，并且这些基因的表观遗传和翻译后修饰与盐胁迫耐受性有关。我们的数据表明CBP20/80依赖性蛋白泛素化/类泛素化与盐胁迫响应之间存在联系。
