Key motifs in EBV (Epstein-Barr virus)-encoded protein kinase for phosphorylation activity and nuclear localization.
A sole EBV (Epstein-Barr virus)-encoded protein kinase (EBV-PK) (the BGLF4 gene product) plays important roles in viral infection. Although a number of targets of this protein have been identified, the kinase itself remains largely unstudied with regard to its enzymology and structure. In the present study, site-directed mutagenesis has been employed to generate mutations targeting residues involved in nuclear localization of the EBV-PK, core residues in subdomain III of the protein kinase domain conserved in most protein kinases or residues in subdomain VIa conserved only within the HPK (herpesvirus-encoded protein kinase) group. Deletion of amino acids 389-391 resulted in exclusive cytoplasmic localization of the protein, indicating the involvement of this region in nuclear translocation of the EBV-PK. Mutations at the amino acids Glu113 (core component), Phe175, Leu178, Phe184, Leu185 and Asn186 (conserved in HPKs) resulted in loss of EBV-PK autophosphorylation, protein substrate [EBV EA-D (early antigen diffused)] phosphorylation, and ability to facilitate ganciclovir phosphorylation. These results reiterate the unique features of this group of kinases and present an opportunity for designing more specific antiviral compounds.
Gershburg
Svetlana
S
Department of Medical Microbiology, Immunology and Cell Biology, Southern Illinois University School of Medicine, Springfield, IL 62794, U.S.A.
Murphy
Leann
L
Marschall
Manfred
M
Gershburg
Edward
E
D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D002460:Cell Line; D002467:Cell Nucleus / Q000201:enzymology*; D002843:Chromatin / Q000201:enzymology; D017124:Conserved Sequence / Q000235:genetics; D018698:Glutamic Acid / Q000378:metabolism; D004854:Herpesvirus 4, Human / Q000201:enzymology*; D006801:Humans; D042541:Intracellular Space / Q000378:metabolism; D008969:Molecular Sequence Data; D050505:Mutant Proteins / Q000737:chemistry / Q000378:metabolism; D010766:Phosphorylation; D017354:Point Mutation / Q000235:genetics; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry* / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D016415:Sequence Alignment; D017384:Sequence Deletion; D013329:Structure-Activity Relationship; D014764:Viral Proteins / Q000737:chemistry* / Q000378:metabolism*
D002843:Chromatin; D050505:Mutant Proteins; D011993:Recombinant Fusion Proteins; D014764:Viral Proteins; D018698:Glutamic Acid; C406063:BGLF4 protein, Epstein-Barr virus; D017346:Protein Serine-Threonine Kinases