UL13 Protein Kinase of Herpes Simplex Virus 1 Complexes with Glycoprotein E and Mediates the Phosphorylation of the Viral Fc Receptor: Glycoproteins E and I

Abstract

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.

A full UL13 open reading frame in Marek's disease virus (MDV) is dispensable for tumor formation and feather follicle tropism and cannot restore horizontal virus transmission of rRB-1B in vivo

“…It can phosphorylate itself and at least five other viral proteins: VP22, ICP22, ICP0, the unique-short protein kinase pUS3, and gE [5,6,12,19,20,22]. pUL13 can also phosphorylate cellular factors such as the eukaryotic elongation factor ∂EF-1 [13].…”

Further Analysis of Marek's Disease Virus Horizontal Transmission Confirms That U L 44 (gC) and U L 13 Protein Kinase Activity Are Essential, while U S 2 Is Nonessential

“…The U L 13 gene is highly conserved, not only among the alphaherpesviruses but in all members of the Herpesviridae. In the case of herpes simplex virus 1 (HSV-1), U L 13 was shown to be present in the tegument of enveloped virus and has been shown to autophosphorylate and phosphorylate a large number of viral and host proteins (6,20,21,29,31,36). Morrison et al (28) showed that U L 13 protein kinase activity promotes dissociation of tegument by phosphorylation of tegument proteins, while Moffat and coworkers (26) showed that the varicella zoster virus (VZV) ortholog of U L 13 (ORF47) is required for efficient infection of T lymphocytes and skin in the SCID-hu mouse model.…”

Sequence and Genetic Arrangement of the USRegion of the Monkey B Virus (Cercopithecine Herpesvirus 1) Genome and Comparison with the USRegions of Other Primate Herpesviruses

“…Although only the N-terminal 110 amino acids are available for the BVcy gI (3), only 1 amino acid difference exists between the BVrh and BVcy sequences, indicating that in this variable region there is not significant genotypic variation. A number of potential phosphorylation sites are present in the cytoplasmic tails of the BV and SA8 gI polypeptides, but only one is positionally conserved between the simian and human virus gI sequences (30). Interestingly, the domains of the gI and gE polypeptides that interact with immunoglobulin G and are involved in complexing of gI with gE (1, 2, 7) are not strongly conserved among the different primate virus gI polypeptides.…”