共查询到20条相似文献,搜索用时 15 毫秒
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Dluzen D Li G Tacelosky D Moreau M Liu DX 《The Journal of biological chemistry》2011,286(9):7705-7713
ATF5 loss of function has been shown previously to cause apoptotic cell death in glioblastoma and breast cancer cells but not in non-transformed astrocytes and human breast epithelial cells. The mechanism for the cell type-dependent survival function of ATF5 is unknown. We report here that the anti-apoptotic factor BCL-2 is a downstream target of ATF5 that mediates the prosurvival function of ATF5 in C6 glioma cells and MCF-7 breast cancer cells. ATF5 binds to an ATF5-specific regulatory element that is downstream of and adjacent to the negative regulatory element in the BCL-2 P2 promoter, stimulating BCL-2 expression. Highlighting the critical role of BCL-2 in ATF5-dependent cancer cell survival, expression of BCL-2 blocks death of C6 and MCF-7 cells induced by dominant-negative ATF5, and depletion of BCL-2 impairs ATF5-promoted cell survival. Moreover, we found that BCL-2 expression is not regulated by ATF5 in non-transformed rat astrocytes, mouse embryonic fibroblasts, and human breast epithelial cells, where expression of BCL-2 but not ATF5 is required for cell survival. These findings identify BCL-2 as an essential mediator for the cancer-specific cell survival function of ATF5 in glioblastoma and breast cancer cells and provide direct evidence that the cell type-specific function of ATF5 derives from differential regulation of downstream targets by ATF5 in different types of cells. 相似文献
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Interaction between CCAAT/enhancer binding protein and cyclic AMP response element binding protein 1 regulates human immunodeficiency virus type 1 transcription in cells of the monocyte/macrophage lineage
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Ross HL Nonnemacher MR Hogan TH Quiterio SJ Henderson A McAllister JJ Krebs FC Wigdahl B 《Journal of virology》2001,75(4):1842-1856
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ATF4是含有bZIP结构域的ATF/CREB转录因子家族成员,对胚胎的发育以及细胞的增殖、分化有重要的调节作用。制备ATF4的多克隆抗体对于研究其在斑马鱼心脏发育过程中的作用有重要的意义。研究首先通过生物信息学方法,选择ATF4基因中特异性强、具亲水性的一段核苷酸序列(1017bp),通过PCR扩增,将片段重组到原核表达载体pET-28a,然后转化入Rosetta菌株中。经测序鉴定正确后,用IPTG诱导表达融合蛋白,以该融合蛋白免疫小鼠,获得ATF4多克隆抗鼠血清。对该多抗血清抗体进行验证,具有很好特异性和较高效价,可以用作Western—blotting、免疫印迹等试验分析。 相似文献
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Trevisan R Daprai L Paloschi L Vajente N Chieco-Bianchi L Saggioro D 《Experimental cell research》2006,312(8):1390-1400
Defects in the regulation of programmed cell death play a fundamental role in the development of neoplasia and neurological disorders, both of which are linked to the human T-cell leukemia/lymphoma virus type 1 (HTLV-1) infection. We previously showed that the HTLV-1 Tax protein protects from apoptosis induced by serum starvation by preventing cytochrome c release and Bax relocation to mitochondria, two early events in the mitochondrial apoptotic pathway. As a natural extension of these findings, and to better define the action of Tax, in the present study, we investigated the outcome of Tax and two mutants which are inactive in CREB/ATF (M47) or NF-kappaB (M22) pathways, in the control of apoptosis induced by the proapoptotic Bax protein. We found that activation of CREB, rather than NF-kappaB, is a key phenomenon in preventing apoptosis. Furthermore, the importance of CREB activation is strengthened by experiments with CREB mutants, treatment with forskolin, and in situ analysis of P-CREB status in cells transfected with Tax or its nonprotecting M47 mutant. Considered together, these results underscore a primary role of CREB in preventing apoptosis triggered by Bax, and suggest that Tax might act by affecting the phosphorylation state of CREB. 相似文献
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Prostaglandin E-induced signal transduction pathways in human T cells from healthy and uveal melanoma-bearing subjects were studied. Transfection experiments showed that PGE2 was able to phosphorylate and activate the fusion trans-activator of the cAMP responsive element-binding protein (CREB). Phosphorylation was at least partially mediated by protein kinase A, as evidenced by the effects of specific kinase inhibitors. Western blotting experiments, which were performed to identify the CREB/ATF2 family members involved in the response to PGE2, revealed a modulation of proteins CREB1, CREB2 and ATF2 and phosphorylation of the 43 kDa form of CREB. Experiments of immunoprecipitation with CREB-binding protein (CBP) demonstrated that, after PGE2 treatment, all of the CREB/ATF isoforms studied, as well as the phosphorylated form of CREB (p-CREB), interacted with CBP. In basal conditions, T cells from patients with conjunctiva basal cell carcinoma showed the presence of p-CREB, which coimmunoprecipitated with CBP. CREB phosphorylation did not modify after PGE2 treatment whereas the p-CREB fraction bound to CBP increased in a delayed manner compared to normal subjects. 相似文献
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