Intracellular localization map of human herpesvirus 8 proteins.
Human herpesvirus 8 (HHV-8) is the etiological agent of Kaposi's sarcoma. We present a localization map of 85 HHV-8-encoded proteins in mammalian cells. Viral open reading frames were cloned with a Myc tag in expression plasmids, confirmed by full-length sequencing, and expressed in HeLa cells. Protein localizations were analyzed by immunofluorescence microscopy. Fifty-one percent of all proteins were localized in the cytoplasm, 22% were in the nucleus, and 27% were found in both compartments. Surprisingly, we detected viral FLIP (v-FLIP) in the nucleus and in the cytoplasm, whereas cellular FLIPs are generally localized exclusively in the cytoplasm. This suggested that v-FLIP may exert additional or alternative functions compared to cellular FLIPs. In addition, it has been shown recently that the K10 protein can bind to at least 15 different HHV-8 proteins. We noticed that K10 and only five of its 15 putative binding factors were localized in the nucleus when the proteins were expressed in HeLa cells individually. Interestingly, in coexpression experiments K10 colocalized with 87% (13 of 15) of its putative binding partners. Colocalization was induced by translocation of either K10 alone or both proteins. These results indicate active intracellular translocation processes in virus-infected cells. Specifically in this framework, the localization map may provide a useful reference to further elucidate the function of HHV-8-encoded genes in human diseases.
Sander
Gaby
G
University of Erlangen-Nuremberg, Department of Surgery, Division of Molecular and Experimental Surgery, Schwabachanlage 10, D-91054 Erlangen, Germany.
Konrad
Andreas
A
Thurau
Mathias
M
Wies
Effi
E
Leubert
Rene
R
Kremmer
Elisabeth
E
Dinkel
Holger
H
Schulz
Thomas
T
Neipel
Frank
F
Stürzl
Michael
M
D000595:Amino Acid Sequence; D002467:Cell Nucleus / Q000737:chemistry; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D003593:Cytoplasm / Q000737:chemistry; D004721:Endoplasmic Reticulum / Q000737:chemistry; D006056:Golgi Apparatus / Q000737:chemistry; D006367:HeLa Cells; D019288:Herpesvirus 8, Human / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D014764:Viral Proteins / Q000032:analysis* / Q000235:genetics / Q000378:metabolism
D014764:Viral Proteins