Wild type RTA and less toxic variants have distinct requirements for Png1 for their depurination activity and toxicity in Saccharomyces cerevisiae.
Wild type RTA and less toxic variants have distinct requirements for Png1 for their depurination activity and toxicity in Saccharomyces cerevisiae.
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DOI：
10.1371/journal.pone.0113719
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发表时间：
2014
期刊：
影响因子：
3.7
通讯作者：
Tumer NE
中科院分区：
文献类型：
--
作者：
Yan Q;Li XP;Tumer NE
蓖麻毒素A链（RTA）经历逆行运输，并被假定使用内质网（ER）相关降解（ERAD）途径的成分进入细胞质以去嘌呤核糖体。然而，目前尚不清楚RTA在进入细胞质后如何避免蛋白酶体的降解。我们在酵母中观察到野生型RTA前体形式和在其c末端标记有增强绿色荧光蛋白（EGFP）的无毒变体之间的两种不同的运输模式。其中一组，包括野生型RTA，经历了ER到液泡的运输，而另一组，包括G83D变体，在ER中形成聚集体，没有运输到液泡。肽：n -聚糖酶（Png1）在ERAD途径中催化未折叠糖蛋白的降解，对野生型RTA和G83D变体的去嘌呤活性和毒性有不同的影响。PreG83D变体在ER膜上被Png1去糖基化，通过促进其降解降低其去嘌呤活性和毒性。相比之下，野生型的preta被细胞质中Png1的自由池去糖基化，这可能是通过阻止其降解来增加其去嘌呤活性。这些结果表明，与G83D变体相比，野生型RTA对Png1有明显的需求，并且在细胞质中被Png1去糖基化，这可能是避免通过ERAD途径降解到达核糖体的一种策略。
Ricin A chain (RTA) undergoes retrograde trafficking and is postulated to use components of the endoplasmic reticulum (ER) associated degradation (ERAD) pathway to enter the cytosol to depurinate ribosomes. However, it is not known how RTA evades degradation by the proteasome after entry into the cytosol. We observed two distinct trafficking patterns among the precursor forms of wild type RTA and nontoxic variants tagged with enhanced green fluorescent protein (EGFP) at their C-termini in yeast. One group, which included wild type RTA, underwent ER-to-vacuole transport, while another group, which included the G83D variant, formed aggregates in the ER and was not transported to the vacuole. Peptide: N-glycanase (Png1), which catalyzes degradation of unfolded glycoproteins in the ERAD pathway affected depurination activity and toxicity of wild type RTA and G83D variant differently. PreG83D variant was deglycosylated by Png1 on the ER membrane, which reduced its depurination activity and toxicity by promoting its degradation. In contrast, wild type preRTA was deglycosylated by the free pool of Png1 in the cytosol, which increased its depurination activity, possibly by preventing its degradation. These results indicate that wild type RTA has a distinct requirement for Png1 compared to the G83D variant and is deglycosylated by Png1 in the cytosol as a possible strategy to avoid degradation by the ERAD pathway to reach the ribosome.
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影响因子：
33.6
作者：
Guerriero CJ;Brodsky JL
通讯作者：
Brodsky JL
影响因子：
3.1
作者：
Li, Xiao-Ping;Baricevic, Marianne;Tumer, Nigun E.
通讯作者：
Tumer, Nigun E.
影响因子：
3.3
作者：
Li, Shuyu;Spooner, Robert A.;Roberts, Lynne M.
通讯作者：
Roberts, Lynne M.
影响因子：
2.9
作者：
Deeks, ED;Cook, JP;Lord, JM
通讯作者：
Lord, JM
DOI：
10.1074/jbc.m808387200
发表时间：
2009-04-10
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
Mayerhofer PU;Cook JP;Wahlman J;Pinheiro TT;Moore KA;Lord JM;Johnson AE;Roberts LM
通讯作者：
Roberts LM