Characterization of the bipartite nuclear localization signal of protein LANA2 from Kaposi's sarcoma-associated herpesvirus.
LANA2 is a nuclear latent protein detected exclusively in Kaposi's sarcoma-associated herpesvirus-infected B cells. The protein inhibits p53-dependent transactivation and apoptosis, suggesting an important role in the transforming activity of the virus. To explore the molecular mechanisms of its nuclear localization, fusion proteins of green fluorescent protein (EGFP) and deletion constructs of LANA2 were expressed in HeLa cells. Only the fragment comprising amino acid residues 355-440 of LANA2 localized in the cell nucleus. This fragment contains two closely located basic domains and forms a putative bipartite nuclear localization signal (NLS). The putative LANA2 NLS was able to target EGFP to the nucleus consistently. Site-directed mutation analyses demonstrated that LANA2 contains a functional bipartite NLS between amino acid positions 367 and 384. In addition, analysis of cells transfected with a cytoplasmic LANA2 mutant revealed that an appropriate subcellular localization may be crucial to regulate p53 activity.
Muñoz-Fontela
Cesar
C
Departamento de Microbiología II, Facultad de Farmacia, Universidad Complutense de Madrid, Plaza Ramon y Cajal sn, 28040 Madrid, Spain.
Rodríguez
Estefanía
E
Nombela
Cesar
C
Arroyo
Javier
J
Rivas
Carmen
C
D021581:Active Transport, Cell Nucleus / Q000235:genetics; D000595:Amino Acid Sequence; D024361:Amino Acids, Basic / Q000737:chemistry; D000956:Antigens, Viral / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D002467:Cell Nucleus / Q000737:chemistry / Q000378:metabolism / Q000821:virology; D049452:Green Fluorescent Proteins; D006367:HeLa Cells; D019288:Herpesvirus 8, Human / Q000737:chemistry* / Q000235:genetics / Q000502:physiology; D006801:Humans; D008164:Luminescent Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D019913:Nuclear Localization Signals / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D009687:Nuclear Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D010446:Peptide Fragments / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D014162:Transfection; D014407:Tumor Cells, Cultured; D016159:Tumor Suppressor Protein p53 / Q000502:physiology; D017735:Virus Latency / Q000235:genetics / Q000502:physiology
D024361:Amino Acids, Basic; D000956:Antigens, Viral; D008164:Luminescent Proteins; D019913:Nuclear Localization Signals; D009687:Nuclear Proteins; D010446:Peptide Fragments; D011994:Recombinant Proteins; D016159:Tumor Suppressor Protein p53; C109540:latency-associated nuclear antigen; D049452:Green Fluorescent Proteins