The Multifunctional Herpes Simplex Virus IE63 Protein Interacts with Heterogeneous Ribonucleoprotein K and with Casein Kinase 2

• Published in: The Journal of biological chemistry Vol. 274; no. 41; pp. 28991 - 28998
• Main Authors: Wadd, Sarah, Bryant, Helen, Filhol, Odile, Scott, James E., Hsieh, Tsai-Yuan, Everett, Roger D., Clements, J. Barklie
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 08.10.1999; American Society for Biochemistry and Molecular Biology
• Subjects: Animals; Casein Kinase II; Cell Line; Cricetinae; Gene Expression Regulation, Viral; HeLa Cells; Herpes simplex virus; Herpes simplex virus 1; Heterogeneous-Nuclear Ribonucleoprotein K; hnRNP K protein; Humans; IE63 protein; Immediate-Early Proteins - genetics; Immediate-Early Proteins - metabolism; Phosphorylation; Precipitin Tests; Protein Binding; Protein-Serine-Threonine Kinases - genetics; Protein-Serine-Threonine Kinases - metabolism; Recombinant Fusion Proteins - genetics; Recombinant Fusion Proteins - metabolism; ribonucleoprotein K; Ribonucleoproteins - genetics; Ribonucleoproteins - metabolism; Saccharomyces cerevisiae; Yeasts - genetics
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.274.41.28991

Herpes simplex virus type 1 (HSV-1), the prototype α-herpesvirus, causes several prominent diseases. The HSV-1 immediate early (IE) protein IE63 (ICP27) is the only regulatory gene with a homologue in every mammalian and avian herpesvirus sequenced so far. IE63 is a multifunctional protein affecting transcriptional and post-transcriptional processes, and it can shuttle from the nucleus to the cytoplasm. To identify interacting cellular proteins, a HeLa cDNA library was screened in the yeast two-hybrid system using IE63 as bait. Several interacting proteins were identified including heterogeneous nuclear ribonucleoprotein K (hnRNP K), a multifunctional protein like IE63, and the β subunit of casein kinase 2 (CK2), a protein kinase, and interacting regions were mapped. Confirmation of interactions was provided by fusion protein binding assays, co-immunoprecipitation from infected cells, and CK2 activity assays. hnRNP K co-immunoprecipitated from infected cells with anti-IE63 serum was a more rapidly migrating subfraction than hnRNP K immunoprecipitated by anti-hnRNP K serum. Using anti-IE63 serum, both IE63 and hnRNP K were phosphorylated in vitro by CK2, while in immunoprecipitates using anti-hnRNP K serum, IE63 but not hnRNP K was phosphorylated by CK2. These data provide important new insights into how this key viral regulatory protein exerts its functions.