Background

The guanine-rich RNA sequence binding factor 1 (GRSF1) is an RNA-binding protein of the hnRNP H/F family, which has been implicated in erythropoiesis, regulation of the redox homeostasis, embryonic brain development, mitochondrial function and cellular senescence. The molecular basis for GRSF1-RNA interaction has extensively been studied in the past but for the time being GRSF1 binding proteins have not been identified.

Methods

To search for GRSF1 binding proteins we first employed the yeast two-hybrid system and screened a cDNA library of human fetal brain for potential GRSF1 binding proteins. Subsequently, we explored the protein-protein-interaction of the recombiant proteins, carried out immunoprecipitation experiments to confirm the interaction of the native proteins in living cells and performed truncation studies to identify the protein-binding motif of GRSF1.

Results

Using the yeast two-hybrid system we identified the COMM-domain containing protein 1 (COMMD1) as specific GRSF1 binding protein and in vitro truncation studies suggested that COMMD1 interacts with the alanine-rich domain of GRSF1. Co-immunoprecipitation strategies indicated that COMMD1-GRSF1 interaction was RNA independent and also occurred in living cells expressing the two native proteins.

Conclusion

In mammalian cells the COMM-domain containing protein 1 (COMMD1) specifically interacts with the Ala-rich domain of GRSF1 in an RNA-independent manner.

General significance

This is the first report describing a specific GRSF1 binding protein.

中文翻译：

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鉴定含有COMM域的蛋白1作为富含鸟嘌呤的RNA序列结合因子1的特异性结合伴侣。

背景

富含鸟嘌呤的RNA序列结合因子1（GRSF1）是hnRNP H / F家族的RNA结合蛋白，与红细胞生成，氧化还原稳态的调节，胚胎脑发育，线粒体功能和细胞衰老有关。过去已经广泛研究了GRSF1-RNA相互作用的分子基础，但目前尚未鉴定出GRSF1结合蛋白。

方法

为了搜索GRSF1结合蛋白，我们首先采用了酵母双杂交系统，并筛选了人胎脑的cDNA文库以寻找潜在的GRSF1结合蛋白。随后，我们探索了重组蛋白的蛋白-蛋白相互作用，进行了免疫沉淀实验以确认天然蛋白在活细胞中的相互作用，并进行了截短研究以鉴定GRSF1的蛋白结合基序。

结果

使用酵母双杂交系统，我们确定了包含COMM域的蛋白1（COMMD1）为特定的GRSF1结合蛋白，体外截短研究表明COMMD1与GRSF1的富含丙氨酸的域相互作用。免疫共沉淀策略表明COMMD1-GRSF1相互作用是RNA无关的，并且也发生在表达两种天然蛋白的活细胞中。

结论

在哺乳动物细胞中，包含COMM域的蛋白质1（COMMD1）以不依赖RNA的方式与GRSF1的富含Ala的域相互作用。

一般意义

这是描述特定GRSF1结合蛋白的第一份报告。