Aph2, a protein with a zf-DHHC motif, interacts with c-Abl and has pro-apoptotic activity
Aph2, a protein with a zf-DHHC motif, interacts with c-Abl and has pro-apoptotic activity
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DOI：
10.1074/jbc.m202388200
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发表时间：
2002-08-09
影响因子：
4.8
通讯作者：
Goff, SP
中科院分区：
文献类型：
--
作者：
Li, BJ;Cong, F;Goff, SP
c-Abl是一种非受体酪氨酸激酶，参与DNA损伤诱导的细胞死亡和生长因子受体信号传导。为了进一步了解c-Abl的功能和调节，进行酵母双杂交筛选以鉴定c-Abl相互作用蛋白。在这里，我们报告的鉴定，嗜酸性蛋白2（Aph 2），编码一种新的蛋白质与一个独特的富含半胱氨酸的基序（zf-DHHC）和53个氨基酸的延伸共享同源性的肌酸激酶家族。zf-DHHC结构域从酵母到人是高度保守的。两个蛋白质含有这个基序，Akr 1 p和Erf 2 p，已被鉴定在酿酒酵母，都牵连在信号通路。双杂交缺失分析表明Aph 2的N端与c-Abl的C端相互作用，免疫共沉淀分析表明Aph 2与c-Abl相互作用。Aph 2在大多数测试的组织中表达，并且定位于细胞质中，主要在内质网（ER）中。ER定位所需的序列位于Aph 2的N末端和zfDHHC基序中。据报道，c-Abl的一部分位于ER中。我们在这里证明，Aph 2和c-Abl共定位在ER区域。如TUNEL分析所证实的，Aph 2的过表达导致细胞凋亡，并且细胞凋亡的诱导需要N末端。c-AbI和Aph 2的共表达对细胞凋亡诱导具有协同作用，并导致两种蛋白质的表达降低，这表明这两种蛋白质相互下调或表达c-AbI和Aph 2的细胞迅速从培养物中消失。这些结果表明Aph 2可能参与了内质网应激诱导的细胞凋亡，其中c-Abl起着重要作用。
c-Abl is a non-receptor tyrosine kinase implicated in DNA damage-induced cell death and in growth factor receptor signaling. To further understand the function and regulation of c-Abl, a yeast two-hybrid screen was performed to identify c-Abl-interacting proteins. Here we report the identification of Abl-philin 2 (Aph2), encoding a novel protein with a unique cysteine-rich motif (zf-DHHC) and a 53-amino acid stretch sharing homology with the creatine kinase family. The zf-DHHC domain is highly conserved from yeast to human. Two proteins containing this motif, Akr1p and Erf2p, have been characterized in Saccharomyces cerevisiae, both implicated in signaling pathways. Deletion analysis by two-hybrid assays revealed that the N-terminal portion of Aph2 interacts with the C terminus of c-Abl. Aph2 was demonstrated to interact with c-Abl by co-immunoprecipitation assays. Aph2 is expressed in most tissues tested and is localized in the cytoplasm, mainly in the endoplasmic reticulum (ER). The sequences required for ER location reside in the N terminus and the zfDHHC motif of Aph2. It has been reported that a portion of c-Abl is localized in the ER. We demonstrate here that Aph2 and c-Abl are co-localized in the ER region. Overexpression of Aph2 leads to apoptosis as justified by TUNEL assays, and the induction of apoptosis requires the N terminus. Co-expression of c-AbI and Aph2 had a synergistic effect on apoptosis induction and led to a decreased expression of both proteins, suggesting either that these two proteins are mutually down-regulated or that cells expressing both c-Abl and Aph2 rapidly disappeared from the culture. These results suggest that Aph2 may be involved in ER stress-induced apoptosis in which c-Abl plays an important role.