Stress-inducible transcription factor CHOP/gadd153 induces apoptosis in mammalian cells via p38 kinase-dependent and -independent mechanisms
Stress-inducible transcription factor CHOP/gadd153 induces apoptosis in mammalian cells via p38 kinase-dependent and -independent mechanisms
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DOI：
10.1006/excr.2001.5248
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发表时间：
2001-07-15
影响因子：
3.7
通讯作者：
Habener, JF
中科院分区：
文献类型：
--
作者：
Maytin, EV;Ubeda, M;Habener, JF
CHOP/gadd 153是一种由细胞应激诱导的转录因子，如紫外线、遗传毒性剂和内质网中的蛋白质错误折叠。这些应激诱导CHOP表达，同时引起细胞凋亡的事实表明，CHOP可能直接参与细胞凋亡，然而，证据是间接的。在这里，我们表明，CHOP可以直接诱导细胞凋亡。GFP标记的CHOP载体在几种细胞类型（3 T3成纤维细胞、角质形成细胞和HeLa细胞）中异位过表达，引起细胞凋亡，如通过形态学、DNA片段化和FAGS分析所定义的。使用快速荧光测定法定量细胞凋亡，所述快速荧光测定法测量来自培养物上清液中收集的细胞的信号。还检查了先前显示磷酸化CHOP的p38激酶的促凋亡调节作用。同时过表达CHOP和p38可显著增加细胞凋亡。然而，尽管p38激酶明显调节全长CHOP的活性，但它不是绝对必需的。缺失作图实验表明，CHOP的bZIP区域刺激细胞凋亡的程度与野生型CHOP几乎相同。因此，虽然CHOP的氨基末端区域起到重要的调节作用（即，通过p38的调节），CHOP的潜在的骨化诱导活性存在于分子的bZIP区域内。(C)北京：科学出版社.
CHOP/gadd153 is a transcription factor induced by cellular stresses such as UV light, genotoxic agents, and protein misfolding in the endoplasmic reticulum. The fact that these stresses induce CHOP expression, and at the same time cause cellular apoptosis, suggests that CHOP may be directly involved in apoptosis, However, evidence has been circumstantial. Here, we show that CHOP can directly induce apoptosis. A GFP-tagged CHOP vector, ectopically overexpressed in several cell types (3T3 fibroblasts, keratinocytes, and HeLa cells), caused apoptosis as defined by morphology, DNA fragmentation, and FAGS analysis. Apoptosis was quantified using a rapid fluorescence assay that measures the signal from cells collected in culture supernatants. The apoptosis-modulating effects of p38 kinase, previously shown to phosphorylate CHOP, were also examined. Simultaneous overexpression of CHOP and p38 significantly augmented apoptosis, However, although p38 kinase clearly modulated the activity of full-length CHOP, it was not absolutely required. Deletion mapping experiments showed that the bZIP region of CHOP stimulates apoptosis to nearly the same extent as wild-type CHOP, Thus, while the amino-terminal region of CHOP serves an important modulatory role (i.e., regulation by p38), the underlying apoptosis-inducing activity of CHOP resides within the bZIP region of the molecule. (C) 2001 Academic Press.