The 37-amino-acid interdomain of dengue virus NS5 protein contains a functional NLS and inhibitory CK2 site.
The dengue virus NS5 RNA-dependent RNA polymerase has been detected in the nucleus of virus-infected mammalian cells. We demonstrate here for the first time using in vitro and in vivo assay systems that the 37-amino-acid linker interdomain of NS5 (residues 369 to 405) contains a nuclear localization sequence (NLS) which is capable of targeting b-galactosidase to the nucleus. Further, we show that the linker is recognized by subunits of the NLS-binding importin complex with an affinity similar to that of the bipartite NLS of the retinoblastoma protein and, in analogous fashion to proteins such as the SV40 large tumor antigen, contains a functional protein kinase CK2 phosphorylation site (threonine 395). Interestingly, this site appears to inhibit NS5 nuclear targeting, probably through a cytoplasmic retention mechanism. The linker may have an important role in targeting NS5 to the nucleus in a regulated manner during the dengue virus infectious cycle.
Forwood
J K
JK
Department of Biochemistry and Molecular Biology, James Cook University of North Queensland, Townsville, Australia.
Brooks
A
A
Briggs
L J
LJ
Xiao
C Y
CY
Jans
D A
DA
Vasudevan
S G
SG
D000255:Adenosine Triphosphate / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D001685:Biological Factors / Q000378:metabolism; D001692:Biological Transport / Q000187:drug effects; D047390:Casein Kinase II; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism; D016384:Consensus Sequence; D003600:Cytosol / Q000378:metabolism; D003716:Dengue Virus / Q000201:enzymology*; D004926:Escherichia coli / Q000235:genetics; D007700:Kinetics; D008969:Molecular Sequence Data; D019913:Nuclear Localization Signals / Q000502:physiology*; D010766:Phosphorylation / Q000187:drug effects; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism* / Q000494:pharmacology; D012324:RNA-Dependent RNA Polymerase / Q000737:chemistry / Q000378:metabolism; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000008:administration & dosage / Q000737:chemistry / Q000378:metabolism; D014407:Tumor Cells, Cultured; D017361:Viral Nonstructural Proteins / Q000737:chemistry* / Q000378:metabolism
D001685:Biological Factors; C096041:NS5 protein, flavivirus; D019913:Nuclear Localization Signals; D011993:Recombinant Fusion Proteins; D017361:Viral Nonstructural Proteins; D000255:Adenosine Triphosphate; D047390:Casein Kinase II; D017346:Protein Serine-Threonine Kinases; D012324:RNA-Dependent RNA Polymerase