Targeting of HIV-1 Nef to the centrosome: implications for antigen processing.
To gain a better understanding of the intracellular sites of antigen processing we have looked at the localization of human immunodeficiency virus (HIV)-1 Nef protein by confocal microscopic and biochemical means. We found that ubiquitin (Ub)-Nef fusion proteins were localized to the centrosome in transfected COS-7 cells, and that the colocalization was inhibited by the microtubule-disrupting agent, nocodazole. Interestingly, we found that Ub-Nef trafficking to the centrosome was not dependent upon the metabolic stability of Ub-Nef nor on the inhibition of proteasome activity. We also analyzed the MHC class I antigen processing of a reporter epitope linked to the Ub-Nef fusion proteins and found that Ub-Nef was processed in COS-7 cells. In addition, we show that this processing was inhibited by nocodazole. We suggest that the centrosome may serve as a site of antigen processing in vivo.
Lacaille
V G
VG
Immunology Program, H. Lee Moffitt Cancer Center and Research Institute, Department of Biochemistry and Molecular Biology, University of South Florida College of Medicine, Tampa, FL 33612, USA.
Androlewicz
M J
MJ
D000818:Animals; D017951:Antigen Presentation / Q000187:drug effects; D001483:Base Sequence; D019556:COS Cells; D018385:Centrosome / Q000187:drug effects / Q000276:immunology / Q000378:metabolism*; D017931:DNA Primers / Q000235:genetics; D015693:Gene Products, nef / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D015497:HIV-1 / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D006801:Humans; D015739:Nocodazole / Q000494:pharmacology; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D054311:nef Gene Products, Human Immunodeficiency Virus
D017931:DNA Primers; D015693:Gene Products, nef; D011993:Recombinant Fusion Proteins; D054311:nef Gene Products, Human Immunodeficiency Virus; D015739:Nocodazole