Toxicity of ricin A chain is reduced in mammalian cells by inhibiting its interaction with the ribosome.
Toxicity of ricin A chain is reduced in mammalian cells by inhibiting its interaction with the ribosome.
复制标题
ricin A链的毒性通过抑制其与核糖体的相互作用来降低。
DOI：
10.1016/j.taap.2016.09.004
复制
发表时间：
2016-11-01
影响因子：
3.8
通讯作者：
Cohick, Wendie S.
中科院分区：
文献类型：
--
作者：
Jetzt, Amanda E.;Li, Xiao-Ping;Tumer, Nilgun E.;Cohick, Wendie S.
蓖麻毒素是一种有效的核毒素，由于其易于分离和气雾化，被认为是一种生物恐怖威胁。在酵母中，精氨酸残基远离活性部位的突变会导致蓖麻毒素A链(RTA)变异体无法与核糖体结合，并表现出降低的细胞毒性。本工作的目的是确定这些残基是否有助于RTA在哺乳动物细胞中的核糖体结合和细胞毒性。RTA突变体R193A/R235A不与哺乳动物核糖体相互作用，而G212E突变体在其活性部位附近有点突变，与野生型(WT)RTA类似地结合核糖体。R193A/R235A对裸RNA保持完全催化活性，但对哺乳动物核糖体活性降低。为了确定该突变体在完整细胞中的作用，分别表达了含有指向内质网的信号序列的Pre R193A/R235A和直接针对胞浆核糖体的成熟R193A/R235A。与WT相比，R193A/R235A成熟前和成熟后排尿和蛋白质合成抑制均减少。与G212E相比，R193A/R235A对蛋白质合成的抑制作用减弱程度更大。与WT RTA相比，R193A/R235A前引起的caspase活性降低和线粒体膜电位丧失的程度比G212E更大。这些发现表明，核糖体结合减少的RTA变异体比催化活性较低但核糖体结合活性正常的变异体毒性较小。毒素与核糖体的相互作用为预防或治疗蓖麻毒素中毒提供了新的靶点。
Ricin is a potent ribotoxin that is considered a bioterror threat due to its ease of isolation and possibility of aerosolization. In yeast, mutation of arginine residues away from the active site results in a ricin toxin A chain (RTA) variant that is unable to bind the ribosome and exhibits reduced cytotoxicity. The goal of the present work was to determine if these residues contribute to ribosome binding and cytotoxicity of RTA in mammalian cells. The RTA mutant R193A/R235A did not interact with mammalian ribosomes, while a G212E variant with a point mutation near its active site bound ribosomes similarly to wild-type (WT) RTA. R193A/R235A retained full catalytic activity on naked RNA but had reduced activity on mammalian ribosomes. To determine the effect of this mutant in intact cells, pre R193A/R235A containing a signal sequence directing it to the endoplasmic reticulum and mature R193A/R235A that directly targeted cytosolic ribosomes were each expressed. Depurination and protein synthesis inhibition were reduced by both pre- and mature R193A/R235A relative to WT. Protein synthesis inhibition was reduced to a greater extent by R193A/R235A than by G212E. Pre R193A/R235A caused a greater reduction in caspase activation and loss of mitochondrial membrane potential than G212E relative to WT RTA. These findings indicate that an RTA variant with reduced ribosome binding is less toxic than a variant with less catalytic activity but normal ribosome binding activity. The toxin-ribosome interaction represents a novel target for the development of therapeutics to prevent or treat ricin intoxication.
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影响因子：
3.7
作者：
Herrera C;Klokk TI;Cole R;Sandvig K;Mantis NJ
通讯作者：
Mantis NJ
影响因子：
4.4
作者：
Lindauer, Meghan L.;Wong, John;Magun, Bruce E.
通讯作者：
Magun, Bruce E.
影响因子：
2.8
作者：
Bai, Yan;Watt, Beth;Robertus, Jon D.
通讯作者：
Robertus, Jon D.
DOI：
10.1046/j.1432-1327.2001.02091.x
发表时间：
2001-04-01
期刊：
EUROPEAN JOURNAL OF BIOCHEMISTRY
影响因子：
--
作者：
Chan, SH;Hung, FSJ;Shaw, PC
通讯作者：
Shaw, PC
影响因子：
3.6
作者：
Chiou JC;Li XP;Remacha M;Ballesta JP;Tumer NE
通讯作者：
Tumer NE