SelT, SelW, SelH, and Rdx12: Genomics and molecular insights into the functions of selenoproteins of a novel thioredoxin-like family
SelT, SelW, SelH, and Rdx12: Genomics and molecular insights into the functions of selenoproteins of a novel thioredoxin-like family
复制标题
DOI：
10.1021/bi602462q
复制
发表时间：
2007-06-12
期刊：
影响因子：
2.9
通讯作者：
Gladyshev, Vadim N.
中科院分区：
文献类型：
--
作者：
Dikiy, Alexander;Novoselov, Sergey V.;Gladyshev, Vadim N.
硒是许多生命形式中必需的微量元素，因为它作为硒蛋白中的硒代半胱氨酸 (Sec) 残基存在。然而，大多数哺乳动物硒蛋白没有已知的功能。在此，我们进行了广泛的序列相似性搜索，以定义和表征一个新的蛋白质家族，命名为 Rdx，其中包括哺乳动物含硒蛋白 SelW、SelV、SelT 和 SelH、细菌 SelW 样蛋白和在生命的所有三个领域中功能未知的含半胱氨酸蛋白。该家族的另一个成员是哺乳动物含半胱氨酸蛋白，称为 Rdx12，及其鱼类硒蛋白直系同源物。 Rdx 蛋白被认为具有硫氧还蛋白样折叠和保守的 CxxC 或 CxxU（U 是 Sec）基序，表明其具有氧化还原功能。我们克隆并表征了该家族的三个哺乳动物成员，它们在小鼠组织中表现出不同的表达模式，在用相应的 GFP 融合蛋白转染的细胞中表现出不同的定位模式。与硫氧还蛋白类似，Rdx 蛋白可以使用催化半胱氨酸（或 Sec）与底物蛋白形成瞬时混合二硫化物。我们利用这一特性，使用含有 Rdx 蛋白突变体的亲和柱来识别 Rdx 蛋白的细胞靶标。 Rdx12被发现与谷胱甘肽过氧化物酶1相互作用。而14-3-3蛋白被确定为哺乳动物SelW的靶标之一，这表明14-3-3蛋白家族的氧化还原调节机制。
Selenium is an essential trace element in many life forms due to its occurrence as a selenocysteine (Sec) residue in selenoproteins. The majority of mammalian selenoproteins, however, have no known function. Herein, we performed extensive sequence similarity searches to define and characterize a new protein family, designated Rdx, that includes mammalian selenoproteins SelW, SelV, SelT and SelH, bacterial SelW-like proteins and cysteine-containing proteins of unknown function in all three domains of life. An additional member of this family is a mammalian cysteine-containing protein, designated Rdx12, and its fish selenoprotein orthologue. Rdx proteins are proposed to possess a thioredoxin-like fold and a conserved CxxC or CxxU (U is Sec) motif, suggesting a redox function. We cloned and characterized three mammalian members of this family, which showed distinct expression patterns in mouse tissues and different localization patterns in cells transfected with the corresponding GFP fusion proteins. By analogy to thioredoxin, Rdx proteins can use catalytic cysteine (or Sec) to form transient mixed disulfides with substrate proteins. We employed this property to identify cellular targets of Rdx proteins using affinity columns containing mutant versions of these proteins. Rdx12 was found to interact with glutathione peroxidase 1. whereas 14-3-3 protein was identified as one of the targets of mammalian SelW, suggesting a mechanism for redox regulation of the 14-3-3 family of proteins.