Molecular and functional characterization of a novel splice variant of ANKHD1 that lacks the KH domain and its role in cell survival and apoptosis
Molecular and functional characterization of a novel splice variant of ANKHD1 that lacks the KH domain and its role in cell survival and apoptosis
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DOI：
10.1111/j.1742-4658.2005.04821.x
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发表时间：
2005-08-01
期刊：
影响因子：
5.4
通讯作者：
Ayyavoo, V
中科院分区：
文献类型：
--
作者：
Miles, MC;Janket, ML;Ayyavoo, V
多锚蛋白重复基序蛋白在蛋白-蛋白相互作用中起着重要作用。已知ANKHD1蛋白具有多个锚蛋白重复结构域和一个未知功能的KH结构域。利用酵母双杂交系统分析，我们鉴定出一种新的ANKHD1剪接变体。ANKHD1的这种剪接变体，我们将其命名为HIV-1 vpr结合锚蛋白重复序列（VBARP），它不包含标志性的KH结构域，并且只编码一个锚蛋白重复序列基序。我们通过分子和功能分析对VBARP进行了表征，发现VBARP在不同组织和不同谱系的细胞系中普遍表达。此外，BLAST搜索结果显示，VBARP的同源物和同源物存在于不同的门中，这表明VBARP可能具有进化保守性，可能参与基本的细胞功能。此外，生化分析显示存在两个VBARP亚型，分别编码69和49 kDa多肽，主要定位于细胞质中。使用短干扰RNA方法进行的功能分析表明，该基因产物通过调节半胱天冬酶对细胞存活至关重要。综上所述，这些结果表明VBARP是ANKHD1的一个新的剪接变体，并可能在细胞凋亡（抗凋亡）和细胞存活途径中发挥作用。
Multiple ankyrin repeat motif-containing proteins play an important role in protein-protein interactions. ANKHD1 proteins are known to possess multiple ankyrin repeat domains and a single KH domain with no known function. Using yeast two-hybrid system analysis, we identified a novel splice variant of ANKHD1. This splice variant of ANKHD1, which we designated as HIV-1 Vpr-binding ankyrin repeat protein (VBARP), does not contain the signature KH domain, and codes for only a single ankyrin repeat motif. We characterized VBARP by molecular and functional analysis, revealing that VBARP is ubiquitously expressed in different tissues as well as cell lines of different lineage. In addition, BLAST searches indicated that orthologs and homologs to VBARP exist in different phyla, suggesting that VBARP might be evolutionarily conserved, and thus may be involved in basic cellular function(s). Furthermore, biochemical analysis revealed the presence of two VBARP isoforms coding for 69 and 49 kDa polypeptides, respectively, that are primarily localized in the cytoplasm. Functional analysis using short interfering RNA approaches indicate that this gene product is essential for cell survival through its regulation of caspases. Taken together, these results indicate that VBARP is a novel splice variant of ANKHD1 and may play a role in cellular apoptosis (antiapoptotic) and cell survival pathway(s).