Processing and Localization of the African Swine Fever Virus CD2v Transmembrane Protein
Processing and Localization of the African Swine Fever Virus CD2v Transmembrane Protein
复制标题
DOI：
10.1128/jvi.01994-10
复制
发表时间：
2011-04-01
影响因子：
5.4
通讯作者：
Dixon, Linda K.
中科院分区：
文献类型：
--
作者：
Goatley, Lynnette C.;Dixon, Linda K.
非洲猪瘟病毒 (ASFV) 编码的 CD2v 跨膜蛋白是受感染细胞周围红细胞的血液吸附所必需的，也是抑制旁观者淋巴细胞响应有丝分裂原而增殖所必需的。我们通过在 N 末端附近信号肽下游带有 V5 标签和在 C 末端带有血凝素 (HA) 标签的基因表达来研究 CD2v 的表达。在 ASFV 感染的细胞中，检测到 CD2v 蛋白的全长糖基化形式（主要以 89 kDa 产物的形式迁移），以及 63 kDa 的 N 端糖基化片段和 26 kDa 的 C 端非糖基化片段。所有这些形式的蛋白质都位于细胞膜部分。 26-kDa C 末端片段也在用布雷菲德菌素 A 处理的感染细胞中产生。这些数据表明 CD2v 蛋白在管腔结构域内被切割，并且这发生在内质网或高尔基体区室中。共聚焦显微镜显示大部分表达的 CD2v 蛋白位于细胞内而不是细胞表面。将全长 CD2v 的定位与除 12 个膜近端氨基酸外缺乏所有细胞质尾的缺失突变体的定位进行比较表明，细胞质尾内的信号负责全长和 C 端 26-kDa 片段在病毒工厂周围膜内的主要定位，其中包含高尔基体区室的标记。在未感染的细胞中未观察到 CD2v 蛋白的加工，表明它是由 ASFV 感染诱导的。
The African swine fever virus (ASFV)-encoded CD2v transmembrane protein is required for the hemadsorption of red blood cells around infected cells and is also required for the inhibition of bystander lymphocyte proliferation in response to mitogens. We studied the expression of CD2v by expressing the gene with a V5 tag downstream from the signal peptide near the N terminus and a hemagglutinin (HA) tag at the C terminus. In ASFV-infected cells, a full-length glycosylated form of the CD2v protein, which migrated mainly as a 89-kDa product, was detected, as well as an N-terminal glycosylated fragment of 63 kDa and a C-terminal nonglycosylated fragment of 26 kDa. All of these forms of the protein were localized in the membrane fraction of cells. The 26-kDa C-terminal fragment was also produced in infected cells treated with brefeldin A. These data indicate that the CD2v protein is cleaved within the luminal domain and that this occurs in the endoplasmic reticulum or Golgi compartments. Confocal microscopy showed that most of the expressed CD2v protein was localized within cells rather than at the cell surface. Comparison of the localization of full-length CD2v with that of a deletion mutant lacking all of the cytoplasmic tail apart from the 12 membrane-proximal amino acids indicated that signals within the cytoplasmic tail are responsible for the predominant localization of the full-length and C-terminal 26-kDa fragment within membranes around the virus factories, which contain markers for the Golgi compartment. Processing of the CD2v protein was not observed in uninfected cells, indicating that it is induced by ASFV infection.