Phosphorylation of transcription factor bZIP21 by MAP kinase MPK6-3 enhances banana fruit ripening
Phosphorylation of transcription factor bZIP21 by MAP kinase MPK6-3 enhances banana fruit ripening
复制标题
MAP 激酶 MPK6-3 磷酸化转录因子 bZIP21 可促进香蕉果实成熟
DOI：
10.1093/plphys/kiab539
复制
发表时间：
2021-11-18
期刊：
影响因子：
7.4
通讯作者：
Kuang, Jian-Fei
中科院分区：
文献类型：
--
作者：
Wu, Chao-Jie;Shan, Wei;Kuang, Jian-Fei
肉质果实的成熟涉及多种翻译后修饰(PTM)和动态转录重编程，但PTM之间的相互联系，如蛋白质磷酸化和转录调控，在果实成熟过程中仍有待破译。在此，我们对香蕉成熟过程中的磷酸蛋白质组学进行了分析，鉴定了与49个蛋白质相对应的63个独特的磷酸肽。其中，一个碱性亮氨酸拉链转录因子21(MabZIP21)在成熟期表现出较高的磷酸化水平。在香蕉成熟过程中，MabZIP21转录本和磷酸化丰度增加。全基因组的MabZIP21 DNA结合分析表明，MabZIP21调控的功能基因有助于香蕉的成熟，凝胶迁移率改变分析，染色质免疫沉淀结合定量聚合酶链式反应和双荧光素酶报告分析表明，MabZIP21通过直接与其启动子结合来刺激成熟相关基因的转录。此外，MabZIP21可被参与香蕉成熟的MaMPK6-3磷酸化，T318和S436是重要的磷酸化位点。蛋白质磷酸化增强了MabZIP21介导的转录激活能力，瞬时过表达MabZIP21的磷酸化形式加速了香蕉果实的成熟。此外，MabZIP21通过激活MaMPK6-3及其自身的转录来扩大其在转录调控中的作用。综上所述，本研究揭示了香蕉果实成熟过程中蛋白质磷酸化的一个重要机制，其中MabZIP21是连接MaMPK6-3介导的上游信号和成熟相关基因转录调控的复杂磷酸化途径的一个组成部分。转录因子的蛋白质磷酸化修饰加速香蕉果实的成熟。
Ripening of fleshy fruits involves both diverse post-translational modifications (PTMs) and dynamic transcriptional reprogramming, but the interconnection between PTMs, such as protein phosphorylation and transcriptional regulation, in fruit ripening remains to be deciphered. Here, we conducted a phosphoproteomic analysis during banana (Musa acuminata) ripening and identified 63 unique phosphopeptides corresponding to 49 proteins. Among them, a Musa acuminata basic leucine zipper transcription factor21 (MabZIP21) displayed elevated phosphorylation level in the ripening stage. MabZIP21 transcript and phosphorylation abundance increased during banana ripening. Genome-wide MabZIP21 DNA binding assays revealed MabZIP21-regulated functional genes contributing to banana ripening, and electrophoretic mobility shift assay, chromatin immunoprecipitation coupled with quantitative polymerase chain reaction, and dual-luciferase reporter analyses demonstrated that MabZIP21 stimulates the transcription of a subset of ripening-related genes via directly binding to their promoters. Moreover, MabZIP21 can be phosphorylated by MaMPK6-3, which plays a role in banana ripening, and T318 and S436 are important phosphorylation sites. Protein phosphorylation enhanced MabZIP21-mediated transcriptional activation ability, and transient overexpression of the phosphomimetic form of MabZIP21 accelerated banana fruit ripening. Additionally, MabZIP21 enlarges its role in transcriptional regulation by activating the transcription of both MaMPK6-3 and itself. Taken together, this study reveals an important machinery of protein phosphorylation in banana fruit ripening in which MabZIP21 is a component of the complex phosphorylation pathway linking the upstream signal mediated by MaMPK6-3 with transcriptional controlling of a subset of ripening-associated genes.Protein phosphorylation modification of a transcription factor hastens the ripening of banana fruit.