The pseudorabies virus serine/threonine kinase Us3 contains mitochondrial, nuclear and membrane localization signals
The pseudorabies virus serine/threonine kinase Us3 contains mitochondrial, nuclear and membrane localization signals
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DOI：
10.1023/b:viru.0000032796.27878.7f
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发表时间：
2004-08-01
期刊：
影响因子：
1.6
通讯作者：
Banfield, BW
中科院分区：
文献类型：
--
作者：
Calton, CM;Randall, JA;Banfield, BW
由Us 3基因编码的丝氨酸/苏氨酸激酶在所有已知的α-疱疹病毒中是保守的。据报道，Us 3在病毒生命周期的多个方面发挥作用，包括保护细胞免受病毒诱导的细胞凋亡，将包膜病毒颗粒从核周空间去除以及病毒感染的细胞间传播。在这份报告中，我们研究了亚细胞定位的伪狂犬病病毒（PRV）的Us 3同源。PRV Us 3基因编码两种蛋白，称为Us 3a和Us 3b。Us 3a与Us 3b的不同之处在于它含有54个额外的N-末端氨基酸。在转染的细胞中，Us 3a主要定位于质膜，而Us 3b蛋白主要定位于细胞核。为了探索Us 3a和Us 3b蛋白定位的差异，我们将Us 3a的氨基端54个氨基酸融合到增强型绿色荧光蛋白（EGFP）的氨基端。令人惊讶的是，这种融合蛋白仅定位于转染细胞中的线粒体。转染细胞中突变的Us 3-EGFP融合蛋白的分析揭示Us 3a和Us 3b的羧基末端101个氨基酸包含膜/囊泡定位结构域，并且Us 3b的N末端102个氨基酸包含核定位结构域。我们提供了一个模型，合理化的复杂定位的Us 3a和Us 3b在转染的细胞，并假设线粒体，核和膜定位基序的功能，在报告的抗凋亡，出口和细胞到细胞的传播功能的Us 3。
The serine/threonine kinase encoded by the Us3 gene is conserved amongst all known alpha-herpesviruses. Us3 has been reported to function in a variety of aspects of the virus lifecycle including protection of cells from virus-induced apoptosis, de-envelopment of enveloped virus particles from the perinuclear space and cell-to-cell spread of virus infection. In this report, we examined the sub-cellular localization of the pseudorabies virus (PRV) Us3 homolog. The PRV Us3 gene encodes two proteins termed Us3a and Us3b. Us3a differs from Us3b in that it contains 54 additional N-terminal amino acids. In transfected cells, Us3a localized predominantly to the plasma membrane whereas the Us3b protein localized predominantly to the nucleus. To explore the differences in the localization of the Us3a and Us3b proteins, we fused the amino-terminal 54 amino acids of Us3a to the amino-terminus of the enhanced green fluorescent protein (EGFP). Surprisingly, this fusion protein localized exclusively to mitochondria in transfected cells. Analysis of mutated Us3-EGFP fusion proteins in transfected cells revealed that the carboxy-terminal 101 amino acids of Us3a and Us3b comprises a membrane/vesicular localization domain, and that the N-terminal 102 amino acids of Us3b comprises a nuclear localization domain. We provide a model to rationalize the complex localization of Us3a and Us3b in transfected cells and hypothesize that the mitochondrial, nuclear and membrane localization motifs function in the reported anti-apoptotic, egress and cell-to-cell spread functions of Us3.