Essential stations in the intracellular pathway of cytotoxic bovine seminal ribonuclease
Essential stations in the intracellular pathway of cytotoxic bovine seminal ribonuclease
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DOI：
10.1042/0264-6021:3620553
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发表时间：
2002-03-15
影响因子：
4.1
通讯作者：
D'Alessio, G
中科院分区：
文献类型：
--
作者：
Bracale, A;Spalletti-Cernia, D;D'Alessio, G
牛精液核糖核酸酶（BS-RNase）是一种二聚体核糖核酸酶，对恶性肿瘤细胞具有选择性细胞毒作用。没有关于其从细胞外基质通过细胞溶质的途径的信息，降解rRNA通过免疫荧光研究，通过评估影响特定细胞内隔室的药物对BS-RNase细胞毒性的影响，并通过测定蛋白变体BS-RNase-KDEL的行为，对该途径进行了调查（其中Lys-Asp-Glu-Leu肽片段插入在亚基链的C末端的BS-RNase），具有将蛋白质导向内质网的共有序列。发现BS-RNase可结合正常细胞和恶性细胞，并被核内体囊泡中的两种细胞类型内化。非细胞毒性RNA酶，如RNA酶A和BS-RNA酶的单体衍生物，不结合细胞表面，也不内化。然而，RNA酶A的工程化的、二聚体的和细胞毒性的变体有效地结合并渗透细胞。免疫荧光研究的结果，尼日利亚菌素的影响。莫能菌素和布雷菲德菌素A对精液RNA酶的细胞毒性作用和BS-RNA酶-KDEL变体的行为的研究，得出了这样的结论：恶性细胞中BS-RNA酶从细胞外基质到胞质溶胶的途径具有两个基本的细胞内站：内体和trans-Golgi网络。然而，在正常细胞中，蛋白质不会从内体区室进展到高尔基复合体。
Bovine seminal RNase (BS-RNase) is a dimeric RNase selectively cytotoxic for malignant cells. No information is available on its pathway from the extracellular matrix through the cytosol., where it degrades rRNA. An investigation of this pathway is reported here, carried out by immunofluorescence studies, by assessing the effects on BS-RNase cytotoxicity of drugs that affect specific intracellular compartments and by assaying the behaviour of a protein variant, BS-RNase-KDEL (BS-RNase in which a Lys-Asp-Glu-Leu peptide segment is inserted at the C-terminal ends of the subunit chains), endowed with a consensus sequence that directs proteins to the endoplasmic reticulum. BS-RNase was found to bind both normal and malignant cells and to be internalized by both cell types in endosome vesicles. Noncytotoxic RNases, such as RNase A and a monomeric derivative of BS-RNase, did not bind to the cell surface and were not internalized, However, an engineered, dimeric and cytotoxic variant of RNase A bound effectively and permeated cells. The results of immunofluorescence studies, the effects of nigericin. monensin and brefeldin A on the cytotoxic action of seminal RNase and the behaviour of the BS-RNase-KDEL variant, led to the conclusion that the pathway of BS-RNase in malignant cells from the extracellular matrix to the cytosol has two essential intracellular stations: endosomes and the trans-Golgi network. In normal cells, however, the protein does not progress from the endosomal compartment to the Golgi complex.