PNAS∣玉米在免疫應答過程中，蛋白質的乙醯化分析

02-02

本公眾號（植物科學SCI）主要跟蹤各大植物學期刊最新文獻，比如Nature Plants，Molecular Plant，The Plant Cell，New Phytologist，Plant Physiology 等。
尤其以Nature Plants 為主，該期刊每一篇文獻必定跟蹤閱讀。

2017年12月19日PNAS在線文章，文章結果表明植物編碼的酶的活性可以被調節，以改變免疫應答過程中非組蛋白的乙醯化。

原題目為：

Fungal-induced protein hyperacetylation in maize identified by acetylome profiling

意義：

病原體如何操縱宿主細胞機器來實現感染是生物學中的一個主要問題。玉米圓斑病菌種1感染易感玉米植物的能力依賴於HC-毒素（HCT）的產生。雖然已知HC-毒素是組蛋白脫乙醯酶抑製劑，但HCT實際上如何促進毒力的知識仍然不足。在這裡，我們使用質譜定量HCT處理或病原體感染的植物蛋白質丰度和蛋白乙醯化水平。這些分析表明植物編碼的酶的活性可以被調節，進而在易感的相互作用期間改變組蛋白和非組蛋白乙醯化，並且表明毒性玉米圓斑病菌利用HCT重編程對感染的轉錄響應，導致無效的防禦反應。

Significance：

How pathogens manipulate host cellular machinery to enable infection is a major question in biology. The ability of Cochliobolus carbonum race 1 to infect susceptible corn plants relies on production of HC-toxin (HCT). While it is known that HC-toxin is a histone deacetylase inhibitor, knowledge of how HCT actually promotes virulence has remained elusive. Here, we use mass spectrometry to quantify protein abundance and levels of protein acetylation in HCT-treated or pathogen-infected plants. These analyses revealed that the activity of plant-encoded enzymes can be modulated to alter both histone and nonhistone protein acetylation during a susceptible interaction and suggest that virulent C. carbonum utilizes HCT to reprogram the transcriptional response to infection, resulting in an ineffective defense response.

摘要：

賴氨酸乙醯化是一種重要的翻譯後修飾，調控參與一系列生物過程的多種蛋白質。組蛋白乙醯化在植物防禦中的作用已經確立，並且已知編碼乙醯轉移酶的病原效應蛋白可以直接乙醯化宿主蛋白以改變其免疫力。然而，目前尚不清楚內源性植物酶在免疫應答過程中是否可以調節蛋白乙醯化。在這裡，我們研究了一種由真菌病原菌玉米圓斑病菌種1產生的組蛋白脫乙醯酶抑製劑，效應分子HC-毒素（HCT），它通過改變蛋白乙醯化促進在玉米中的毒性。使用質譜法，我們全面定量了3636種蛋白質的丰度，和用HCT，以及HCT缺陷型或HCT生產型玉米圓斑病菌的菌株處理的玉米的2791個位點處的乙醯化水平。這些數據的分析表明，乙醯化是一種廣泛的翻譯後修飾，影響許多已深入研究的由玉米基因編碼的蛋白質。此外，外源HCT的應用，使我們能夠證明植物編碼的酶（組蛋白脫乙醯酶）的活性可被調節，以改變免疫應答過程中非組蛋白的乙醯化。總的來說，這些結果為進一步的機制研究提供了資源，通過可逆的乙醯化來檢查蛋白質功能的調節，並提供了對由毒性玉米圓斑病菌引起的複雜的免疫應答的理解。

Abstract：

Lysine acetylation is a key posttranslational modification that regulates diverse proteins involved in a range of biological processes. The role of histone acetylation in plant defense is well established, and it is known that pathogen effector proteins encoding acetyltransferases can directly acetylate host proteins to alter immunity. However, it is unclear whether endogenous plant enzymes can modulate protein acetylation during an immune response. Here, we investigate how the effector molecule HC-toxin (HCT), a histone deacetylase inhibitor produced by the fungal pathogen Cochliobolus carbonum race 1, promotes virulence in maize through altering protein acetylation. Using mass spectrometry, we globally quantified the abundance of 3,636 proteins and the levels of acetylation at 2,791 sites in maize plants treated with HCT as well as HCT-deficient or HCT-producing strains of C. carbonum. Analyses of these data demonstrate that acetylation is a widespread posttranslational modification impacting proteins encoded by many intensively studied maize genes. Furthermore, the application of exogenous HCT enabled us to show that the activity of plant-encoded enzymes (histone deacetylases) can be modulated to alter acetylation of nonhistone proteins during an immune response. Collectively, these results provide a resource for further mechanistic studies examining the regulation of protein function by reversible acetylation and offer insight into the complex immune response triggered by virulent C. carbonum.

每日一詞
susceptible
英[s??sept?bl]
美[s??s?pt?b?l]

adj. 易受影響的; 易受感染的; 善感的; 可以接受或允許的;
[例句]Young people are the most susceptible to advertisements
年輕人最容易受廣告的影響。
[其他] 比較級：more susceptible 最高級：most susceptible