Ribonuclease L proteolysis in peripheral blood mononuclear cells of chronic fatigue syndrome patients
Ribonuclease L proteolysis in peripheral blood mononuclear cells of chronic fatigue syndrome patients
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DOI：
10.1074/jbc.m201263200
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发表时间：
2002-09-20
影响因子：
4.8
通讯作者：
Lebleu, B
中科院分区：
文献类型：
--
作者：
Demettre, E;Bastide, L;Lebleu, B
37-kDa结合多肽在慢性疲劳综合征（CFS）患者的外周血单核细胞（PBMC）提取物中积累，并被认为是潜在的诊断标志物（De Meirleir，K.，比斯巴尔角，坎平岛，德贝克尔，P。，Salehzada，T.，Demettre，E.，和Lebleu，B.（2000）Ant.医学杂志108，99-105）。我们在此确定，这种低分子量2- 5A结合多肽是天然2- 5A依赖性核糖核酸酶L（RNase L）的截短形式，由CFS PBMC提取物中蛋白水解活性增加产生。CFS PBMC提取物中的RNA酶L蛋白水解可以在模型系统中模拟，其中重组RNA酶L用人白细胞弹性蛋白酶处理。RNase L蛋白水解导致分子量为37和30 kDa的两个主要片段的积累。37-kDa片段包括2-5A结合位点和天然RNase L的N-末端。30-kDa片段包括RNase L的C-末端部分中的催化位点。有趣的是，RNase L在被CFS PBMC提取物的蛋白酶或被纯化的人白细胞弹性蛋白酶降解成其30-和37-kDa片段时保持活性和2- 5A依赖性。截短的RNase L的2- 5A依赖性核酸酶活性可能是由这些消化产物的缔合引起的，如下拉实验中所建议的。
A 37-kDa binding polypeptide accumulates in peripheral blood mononuclear cell (PBMC) extracts from chronic fatigue syndrome (CFS) patients and is being considered as a potential diagnostic marker (De Meirleir, K., Bisbal, C., Campine, I., De Becker, P., Salehzada, T., Demettre, E., and Lebleu, B. (2000) Ant. J. Med. 108, 99-105). We establish here that this low molecular weight 2-5A-binding polypeptide is a truncated form of the native 2-5A-dependent ribonuclease L (RNase L), generated by an increased proteolytic activity in CFS PBMC extracts. RNase L proteolysis in CFS PBMC extracts can be mimicked in a model system in which recombinant RNase L is treated with human leukocyte elastase. RNase L proteolysis leads to the accumulation of two major fragments with molecular masses of 37 and 30 kDa. The 37-kDa fragment includes the 2-5A binding site and the N-terminal end of native RNase L. The 30-kDa fragment includes the catalytic site in the C-terminal part of RNase L. Interestingly, RNase L remains active and 2-5A-dependent when degraded into its 30- and 37-kDa fragments by proteases of CFS PBMC extract or by purified human leukocyte elastase. The 2-5A-dependent nuclease activity of the truncated RNase L could result from the association of these digestion products, as suggested in pull down experiments.