Accumulation of cyclophilin A isoforms in conditioned medium of irradiated breast cancer cells
Accumulation of cyclophilin A isoforms in conditioned medium of irradiated breast cancer cells
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DOI：
10.1002/pmic.201100319
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发表时间：
2012-06-01
期刊：
影响因子：
3.4
通讯作者：
Lebeau, Jerome
中科院分区：
文献类型：
--
作者：
Chevalier, Francois;Depagne, Jordane;Lebeau, Jerome
分泌的蛋白质在细胞信号传导和通讯中起着关键作用。我们最近发现，电离辐射诱导乳腺癌细胞的延迟细胞死亡，通过可溶性形式的死亡配体的表达介导的死亡受体途径。使用相同的细胞模型，我们的工作的目的是识别扩散因子，细胞照射后分泌，可能参与细胞死亡信号。使用2DE的条件培养基的差异蛋白质组学分析导致在细胞照射后显著调制的许多斑点的检测。使用MALDI-TOF MS和LC-MS/MS方法鉴定相应的蛋白质。有趣的是，在照射细胞的条件培养基中观察到亲环素A的五种亚型增加。这些亚型的等电点和蓄积水平不同。通过照射或辐射敏感性乳腺细胞的条件培养基的蛋白质印迹证实了亲环素A分泌的增加。这些异构体显示出蛋白质成熟和翻译后修饰的有趣模式，包括N-末端甲硫氨酸的交替去除，与乙酰化和甲基化的组合相关。蛋白质的作用进行了讨论，其潜在的参与机制的细胞间的关系和放射敏感性。
Secreted proteins play a key role in cell signaling and communication. We recently showed that ionizing radiations induced a delayed cell death of breast cancer cells, mediated by the death receptor pathways through the expression of soluble forms of death ligands. Using the same cell model, the objective of our work was the identification of diffusible factors, secreted following cell irradiation, potentially involved in cell death signaling. Differential proteomic analysis of conditioned media using 2DE resulted in detection of numerous spots that were significantly modulated following cell irradiation. The corresponding proteins were identified using MALDI-TOF MS and LC-MS/MS approaches. Interestingly, five isoforms of cyclophilin A were observed as increased in conditioned medium of irradiated cells. These isoforms differed in isoelectric points and in accumulation levels. An increase of cyclophilin A secretion was confirmed by Western blotting of conditioned media of irradiated or radiosentive mammary cells. These isoforms displayed an interesting pattern of protein maturation and post-translational modifications, including an alternating removal of N-terminal methionine, associated with a combination of acetylations and methylations. The role of the protein is discussed in relation with its potential involvement in the mechanisms of intercells relationships and radiosensitivity.