Ng T I, Ogle W O, Roizman B
The Marjorie B. Kovler Viral Oncology Laboratories, The University of Chicago, 910 East 58th Street, Chicago, Illinois, 60637, USA.
Virology. 1998 Feb 1;241(1):37-48. doi: 10.1006/viro.1997.8963.
Herpes simplex virus 1 encodes a Fc receptor consisting of glycoproteins E (gE) and I (gI) and two protein kinases specified by UL13 and US3, respectively. We report the following: (i) Antibody to UL13 formed immune complexes containing gE and gI in addition to UL13 protein. Immune complexes formed by monoclonal antibody to gE, but not those formed by monoclonal antibody to gI, also contained the UL13 protein. This association may reflect direct interaction between gE and UL13 inasmuch as IgG in preimmune rabbit serum and an antiserum made against another viral protein which does not react with the UL13 protein directly also bound gE and UL13. (ii) In cells infected with the wild-type virus, gE formed two sharp bands and a diffuse, slower migrating band. The slower sharp band was undetectable, and the diffuse slower migrating forms of gE were diminished in lysates of cells infected with a mutant virus lacking the UL13 gene (DeltaUL13). (iii) Both gE and gI were labeled with 32Pi in cells infected with wild-type or the DeltaUL13 virus, but the labeling was significantly stronger in cells infected with the wild-type virus than in those infected with the DeltaUL13 virus. (iv) In an in vitro protein kinase assay, UL13 immunoprecipitated from cells infected with wild-type virus labeled gE in the presence of [gamma-32P]ATP. This activity was absent in precipitates from cells infected with DeltaUL13 virus. The labeled gE comigrated with the slower, sharp band of gE. (v) gI present in the UL13 immune complex was also phosphorylated in the in vitro kinase assay. (vi) The cytoplasmic domain of gE contains recognition sequences for phosphorylation by casein kinase II (CKII). Exogenous CKII phosphorylated gE in immune complexes from lysates of cells infected with the DeltaUL13 mutant or in immune complexes from lysates of cells infected with wild-type virus that had been heated to inactivate all endogenous kinase activity including that of UL13. In both instances, CKII phosphorylated gE in both the slow and fast migrating sharp bands. We conclude that UL13 physically associates with gE and mediates the phosphorylation of gE and gI. UL13 may also be a determinant in posttranslational processing of gE.
单纯疱疹病毒1编码一种Fc受体，其由糖蛋白E（gE）和I（gI）以及分别由UL13和US3指定的两种蛋白激酶组成。我们报告如下：（i）抗UL13抗体形成的免疫复合物除了包含UL13蛋白外，还含有gE和gI。由抗gE单克隆抗体形成的免疫复合物也含有UL13蛋白，但抗gI单克隆抗体形成的免疫复合物则不然。这种关联可能反映了gE与UL13之间的直接相互作用，因为免疫前兔血清中的IgG以及针对另一种不与UL13蛋白直接反应的病毒蛋白制备的抗血清也能结合gE和UL13。（ii）在感染野生型病毒的细胞中，gE形成两条清晰的条带和一条弥散的、迁移较慢的条带。在缺乏UL13基因的突变病毒（DeltaUL13）感染的细胞裂解物中，较慢的清晰条带无法检测到，gE的弥散较慢迁移形式也减少了。（iii）在感染野生型或DeltaUL13病毒的细胞中，gE和gI均被32Pi标记，但在感染野生型病毒的细胞中的标记明显强于感染DeltaUL13病毒的细胞。（iv）在体外蛋白激酶测定中，从感染野生型病毒的细胞中免疫沉淀的UL13在[γ-32P]ATP存在下标记gE。在感染DeltaUL13病毒的细胞沉淀中不存在这种活性。标记的gE与gE较慢的清晰条带共迁移。（v）UL13免疫复合物中的gI在体外激酶测定中也被磷酸化。（vi）gE的细胞质结构域包含酪蛋白激酶II（CKII）磷酸化的识别序列。外源性CKII使来自感染DeltaUL13突变体的细胞裂解物中的免疫复合物中的gE磷酸化，或使来自感染野生型病毒的细胞裂解物中的免疫复合物中的gE磷酸化，这些细胞裂解物已被加热以灭活所有内源性激酶活性，包括UL13的活性。在这两种情况下，CKII使慢速和快速迁移的清晰条带中的gE磷酸化。我们得出结论，UL13与gE物理结合并介导gE和gI的磷酸化。UL13也可能是gE翻译后加工的一个决定因素。
