Glutathione degradation activity of γ-glutamyl peptidase 1 manifests its dual roles in primary and secondary sulfur metabolism in Arabidopsis.
Glutathione degradation activity of γ-glutamyl peptidase 1 manifests its dual roles in primary and secondary sulfur metabolism in Arabidopsis.
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DOI：
10.1111/tpj.15912
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发表时间：
2022-09
期刊：
影响因子：
7.2
通讯作者：
Ohkama-Ohtsu, Naoko
中科院分区：
文献类型：
--
作者：
Ito, Takehiro;Kitaiwa, Taisuke;Nishizono, Kosuke;Umahashi, Minori;Miyaji, Shunsuke;Agake, Shin-Ichiro;Kuwahara, Kana;Yokoyama, Tadashi;Fushinobu, Shinya;Maruyama-Nakashita, Akiko;Sugiyama, Ryosuke;Sato, Muneo;Inaba, Jun;Hirai, Masami Yokota;Ohkama-Ohtsu, Naoko
关键词：
谷胱甘肽（GSH）作为主要的硫储存库，因此在初级硫代谢中占有重要地位。 GSH 降解导致硫重新分配，并且被认为主要由 γ-谷氨酰环转移酶（GGCT2;1、GGCT2;2 和 GGCT2;3）进行，但这并不能完全解释 GSH 的快速周转。在这里，我们通过酵母互补测定发现 γ-谷氨酰肽酶 1 (GGP1) 有助于 GSH 降解。 GGP1 和 GGP3 的重组蛋白在体外表现出高的 GSH 降解活性，但没有氧化型谷胱甘肽 (GSSG) 的降解活性。值得注意的是，GGP1 转录本在莲座叶中非常丰富，这与 ggp1 突变体无论营养条件如何不断积累更多 GSH 一致。鉴于 GGP 的能量需求比 GGCT 介导的途径更低，GGP 介导的途径可能是比 GGCT 介导的途径更有效的 GSH 降解途径。因此，我们提出了一个模型，其中胞质 GSH 主要由 GGP1 降解，也可能由 GGP3 降解。另一个值得注意的事实是，已知 GGP 可以在芥子油苷和camalexin 合成中处理 GSH 缀合物；事实上，我们证实 ggp1 突变体含有较高水平的 O-乙酰基-l-Ser（硫饥饿的信号分子）和较低水平的芥子油苷及其降解产物。 GGP1 的预测结构进一步为这一假设提供了理论依据。总之，我们认为 GGP1 和可能的 GGP3 在初级和次级硫代谢中都发挥着重要作用。谷胱甘肽 (GSH) 是植物中有机硫的主要储存库。在这项研究中，我们发现了新型 GSH 降解酶，γ-谷氨酰肽酶 (GGP)，它可以在细胞中提供大量的半胱氨酸。此外，GGPs还在芥子油苷和camalexin合成中发挥作用，因此GGPs可以被视为在GSH降解以及芥子油苷和camalexin合成（即初级和次级硫代谢）中发挥重要作用的酶。
Glutathione (GSH) functions as a major sulfur repository and hence occupies an important position in primary sulfur metabolism. GSH degradation results in sulfur reallocation and is believed to be carried out mainly by γ‐glutamyl cyclotransferases (GGCT2;1, GGCT2;2, and GGCT2;3), which, however, do not fully explain the rapid GSH turnover. Here, we discovered that γ‐glutamyl peptidase 1 (GGP1) contributes to GSH degradation through a yeast complementation assay. Recombinant proteins of GGP1, as well as GGP3, showed high degradation activity of GSH, but not of oxidized glutathione (GSSG), in vitro. Notably, the GGP1 transcripts were highly abundant in rosette leaves, in agreement with the ggp1 mutants constantly accumulating more GSH regardless of nutritional conditions. Given the lower energy requirements of the GGP‐ than the GGCT‐mediated pathway, the GGP‐mediated pathway could be a more efficient route for GSH degradation than the GGCT‐mediated pathway. Therefore, we propose a model wherein cytosolic GSH is degraded chiefly by GGP1 and likely also by GGP3. Another noteworthy fact is that GGPs are known to process GSH conjugates in glucosinolate and camalexin synthesis; indeed, we confirmed that the ggp1 mutant contained higher levels of O‐acetyl‐l‐Ser, a signaling molecule for sulfur starvation, and lower levels of glucosinolates and their degradation products. The predicted structure of GGP1 further provided a rationale for this hypothesis. In conclusion, we suggest that GGP1 and possibly GGP3 play vital roles in both primary and secondary sulfur metabolism. Glutathione (GSH) is a major repository for organic sulfur in plants. In this study, we identified novel GSH degradation enzymes, γ‐glutamyl peptidases (GGPs), which may supply a substantial amount of cysteine in the cell. Moreover, GGPs also function in glucosinolate and camalexin synthesis, so GGPs can be regarded as enzymes that play important roles in both GSH degradation and glucosinolate and camalexin synthesis, that is, primary and secondary sulfur metabolism.
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影响因子：
6.9
作者：
Destro T;Prasad D;Martignago D;Bernet IL;Trentin AR;Renu IK;Ferretti M;Masi A
通讯作者：
Masi A
影响因子：
3.3
作者：
Ganguli, Dwaipayan;Kumar, Chitranshu;Bachhawat, Anand Kumar
通讯作者：
Bachhawat, Anand Kumar
影响因子：
5.6
作者：
Bielecka M;Watanabe M;Morcuende R;Scheible WR;Hawkesford MJ;Hesse H;Hoefgen R
通讯作者：
Hoefgen R
影响因子：
7.4
作者：
FUJIWARA, T;HIRAI, MY;NAITO, S
通讯作者：
NAITO, S
影响因子：
56.9
作者：
Alonso, JM;Stepanova, AN;Ecker, JR
通讯作者：
Ecker, JR