The Siva-1 putative amphipathic helical region (SAH) is sufficient to bind to BCL-XL and sensitize cells to UV radiation induced apoptosis
The Siva-1 putative amphipathic helical region (SAH) is sufficient to bind to BCL-XL and sensitize cells to UV radiation induced apoptosis
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DOI：
10.1023/b:appt.0000012125.01799.4c
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发表时间：
2004-01-01
期刊：
影响因子：
7.2
通讯作者：
Prasad, KVS
中科院分区：
文献类型：
--
作者：
Chu, F;Borthakur, A;Prasad, KVS
人类 Siva 基因定位于染色体 14q3233，产生全长主要形式 Siva-1 和次要替代形式 Siva-2，后者似乎缺乏 Siva-1 的促凋亡特性。我们最近的工作表明，Siva-2 中的缺失区域编码一个独特的 20 个氨基酸的推定两亲性螺旋区域（SAH，Siva- 中的残基 36 - 55）。 1）。尽管Siva-1不属于BCL-2家族，但它与抗凋亡蛋白BCL-XL特异性相互作用，并使表达BCL-XL的MCF7乳腺癌细胞对紫外线辐射诱导的细胞凋亡敏感。缺失诱变已将必要的区域映射到 Siva-1 的 SAH 上。在本文中，我们证明 Siva-1 中的 SAH 区域足以与 BCL2 家族的抗凋亡成员（例如 BCL-XL 和 BCL-2）特异性相互作用，但不能与其凋亡成员 BAX 相互作用。使用合成SAH肽的瞬时转染和直接显微注射，我们还证明SAH区域足以抑制BCL-XL介导的细胞存活并使表达BCL-XL的MDA-MB-231和MCF7乳腺癌细胞对UV辐射诱导的细胞凋亡高度敏感。 SAH 介导的 BCL-XL（和/或 BCL2）细胞存活抑制的潜在作用机制似乎是由于线粒体完整性丧失，这反映在细胞色素 c 释放增强导致 caspase 9 和最终 caspase 3 的激活。
The human Siva gene is localized to chromosome 14q3233 and gives rise to the full- length predominant form, Siva- 1 and a minor alternate form, Siva- 2 that appears to lack the proapoptotic properties of Siva- 1. Our recent work has shown that the missing region in Siva- 2 encodes a unique twenty amino acid putative amphipathic helical region ( SAH, residues 36 - 55 in Siva- 1). Despite the fact that Siva- 1 does not belong to the BCL- 2 family, it specifically interacts with the anti- apoptotic protein BCL-XL and sensitizes MCF7 breast cancer cells expressing BCL- XL to UV radiation induced apoptosis. Deletion mutagenesis has mapped the necessary region to the SAH in Siva- 1. In this paper we demonstrate that the SAH region in Siva- 1 is sufficient to specifically interact with the antiapoptotic members of the BCL2 family such as BCL- XL and BCL- 2 but not its apoptotic member BAX. Using transient transfections and direct microinjection of synthetic SAH peptides, we also demonstrate that the SAH region is sufficient to inhibit the BCL- XL mediated cell survival and render MDA- MB- 231 and MCF7 breast cancer cells expressing BCL- XL highly susceptible to UV radiation induced apoptosis. The underlying mechanism of action of SAH mediated inhibition of BCL- XL ( and/ or BCL2) cell survival appears to be due to loss of mitochondrial integrity as reflected in enhanced cytochrome c release leading to the activation of caspase 9 and finally caspase 3.