N-Terminal Acetylation Stabilizes SIGMA FACTOR BINDING PROTEIN1 Involved in Salicylic Acid-Primed Cell Death1[CC-BY]
N-Terminal Acetylation Stabilizes SIGMA FACTOR BINDING PROTEIN1 Involved in Salicylic Acid-Primed Cell Death1[CC-BY]
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N 末端乙酰化可稳定参与水杨酸引发的细胞死亡的 SIGMA 因子结合蛋白 1[CC-BY]
DOI：
10.1104/pp.19.01417
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发表时间：
2020-05-01
期刊：
影响因子：
7.4
通讯作者：
Kim, Chanhong
中科院分区：
文献类型：
--
作者：
Li, Zihao;Dogra, Vivek;Kim, Chanhong
N-末端(NT)乙酰化(NTA)是由核糖体相关的NT-乙酰基转移酶催化的一种丰富的、不可逆的共翻译蛋白质修饰。在酵母和哺乳动物中，特定蛋白质上的NTA可以作为蛋白质分解的降解信号(称为Ac/N-degron)。然而，在植物中，NTA的生物学相关性在很大程度上仍未被探索。在本研究中，我们揭示了拟南芥Sigma因子结合蛋白1(SIB1)，它是水杨酸诱导的细胞死亡的转录辅助调节因子和正调节因子，在启动子Met上经历了绝对的NTA；NT-乙酰转移酶B(NatB)部分参与了这种修饰。虽然NTA会导致某些靶蛋白的不稳定，但我们的遗传和生化分析表明，植物NAB参与的NTA反而使SIB1更稳定。鉴于泛素/蛋白酶体系统刺激SIB1降解，NTA赋予的稳定性似乎确保了SIB1依赖基因的及时表达，主要与免疫反应有关。综合我们的发现，我们在这里报道了在陆地植物中NTA驱动的一种非典型的蛋白质稳定。N-末端乙酰化调节SIB1蛋白质的稳定性，以确保其在水杨酸启动的细胞死亡中的功能。
N-terminal (Nt) acetylation (NTA) is an ample and irreversible cotranslational protein modification catalyzed by ribosome-associated Nt-acetyltransferases. NTA on specific proteins can act as a degradation signal (called an Ac/N-degron) for proteolysis in yeast and mammals. However, in plants, the biological relevance of NTA remains largely unexplored. In this study, we reveal that Arabidopsis (Arabidopsis thaliana) SIGMA FACTOR-BINDING PROTEIN1 (SIB1), a transcription coregulator and a positive regulator of salicylic acid-primed cell death, undergoes an absolute NTA on the initiator Met; Nt-acetyltransferase B (NatB) partly contributes to this modification. While NTA results in destabilization of certain target proteins, our genetic and biochemical analyses revealed that plant NatB-involved NTA instead renders SIB1 more stable. Given that the ubiquitin/proteasome system stimulates SIB1 degradation, it seems that the NTA-conferred stability ensures the timely expression of SIB1-dependent genes, mostly related to immune responses. Taking our findings together, here we report a noncanonical NTA-driven protein stabilization in land plants.N-terminal acetylation regulates SIB1 protein stability to ensure its function in salicylic acid-primed cell death.