Protein-Protein and Protein-Membrane Associations in the Lignin Pathway
Protein-Protein and Protein-Membrane Associations in the Lignin Pathway
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DOI：
10.1105/tpc.112.102566
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发表时间：
2012-11-01
期刊：
影响因子：
11.6
通讯作者：
Werck-Reichhart, Daniele
中科院分区：
文献类型：
--
作者：
Bassard, Jean-Etienne;Richert, Ludovic;Werck-Reichhart, Daniele
酶的超分子组织被认为可以协调代谢复杂性并帮助在不同途径中引导中间体。苯丙素代谢必须将植物固定的高达 30% 的碳引导至木质素前体的生物合成。因此，似乎需要途径中酶的有效偶联。在烟草本塞姆氏叶组织和拟南芥细胞中研究了导致木质素前体的主分支点周围四种连续酶的亚细胞定位、移动性、蛋白质-蛋白质和蛋白质-膜相互作用。 CYP73A5 和 CYP98A3 这两种拟南芥细胞色素 P450 (P450) 催化木质素单体酚环的对位和间位羟基化，被发现在内质网 (ER) 中共定位并形成同聚体和异聚体。它们随着快速重塑的植物内质网一起移动，但它们在内质网表面的横向扩散受到限制，这可能是由于与其他内质网蛋白的结合。发现连接可溶性酶羟基肉桂酰转移酶 (HCT) 与 ER 部分相关。 P450 表达后，HCT 和 4-香豆酰辅酶 A 连接酶都重新定位到更靠近膜的位置。荧光寿命成像显微镜支持 P450 共定位以及与可溶性蛋白的相互作用，并通过伙伴蛋白的表达得到增强。在进行伤口修复的组织中，蛋白质重新定位进一步增强。 CYP98A3 在驱动蛋白质关联方面最有效。
Supramolecular organization of enzymes is proposed to orchestrate metabolic complexity and help channel intermediates in different pathways. Phenylpropanoid metabolism has to direct up to 30% of the carbon fixed by plants to the biosynthesis of lignin precursors. Effective coupling of the enzymes in the pathway thus seems to be required. Subcellular localization, mobility, protein-protein, and protein-membrane interactions of four consecutive enzymes around the main branch point leading to lignin precursors was investigated in leaf tissues of Nicotiana benthamiana and cells of Arabidopsis thaliana. CYP73A5 and CYP98A3, the two Arabidopsis cytochrome P450s (P450s) catalyzing para- and meta-hydroxylations of the phenolic ring of monolignols were found to colocalize in the endoplasmic reticulum (ER) and to form homo-and heteromers. They moved along with the fast remodeling plant ER, but their lateral diffusion on the ER surface was restricted, likely due to association with other ER proteins. The connecting soluble enzyme hydroxycinnamoyltransferase (HCT), was found partially associated with the ER. Both HCT and the 4-coumaroyl-CoA ligase relocalized closer to the membrane upon P450 expression. Fluorescence lifetime imaging microscopy supports P450 colocalization and interaction with the soluble proteins, enhanced by the expression of the partner proteins. Protein relocalization was further enhanced in tissues undergoing wound repair. CYP98A3 was the most effective in driving protein association.