Nucleocapsid Promotes Localization of HIV-1 Gag to Uropods That Participate in Virological Synapses between T Cells
Llewellyn, G. Nicholas
Hogue, Ian B.
Grover, Jonathan R.
- Publisher: Public Library of Science
(issn: 1553-7366, eissn: 1553-7374)
RC581-607 | Research Article | Cell Biology/Membranes and Sorting | Cell Biology/Cell Adhesion | Cell Biology/Cytoskeleton | Cell Biology/Leukocyte Signaling and Gene Expression | Immunologic diseases. Allergy | QH301-705.5 | Infectious Diseases/HIV Infection and AIDS | Infectious Diseases/Viral Infections | Cell Biology/Morphogenesis and Cell Biology | Virology | Virology/Immunodeficiency Viruses | Biology (General) | Virology/Virion Structure, Assembly, and Egress
T cells adopt a polarized morphology in lymphoid organs, where cell-to-cell transmission of HIV-1 is likely frequent. However, despite the importance of understanding virus spread in vivo, little is known about the HIV-1 life cycle, particularly its late phase, in polarized T cells. Polarized T cells form two ends, the leading edge at the front and a protrusion called a uropod at the rear. Using multiple uropod markers, we observed that HIV-1 Gag localizes to the uropod in polarized T cells. Infected T cells formed contacts with uninfected target T cells preferentially via HIV-1 Gag-containing uropods compared to leading edges that lack plasma-membrane-associated Gag. Cell contacts enriched in Gag and CD4, which define the virological synapse (VS), are also enriched in uropod markers. These results indicate that Gag-laden uropods participate in the formation and/or structure of the VS, which likely plays a key role in cell-to-cell transmission of HIV-1. Consistent with this notion, a myosin light chain kinase inhibitor, which disrupts uropods, reduced virus particle transfer from infected T cells to target T cells. Mechanistically, we observed that Gag copatches with antibody-crosslinked uropod markers even in non-polarized cells, suggesting an association of Gag with uropod-specific microdomains that carry Gag to uropods. Finally, we determined that localization of Gag to the uropod depends on higher-order clustering driven by its NC domain. Taken together, these results support a model in which NC-dependent Gag accumulation to uropods establishes a preformed platform that later constitutes T-cell-T-cell contacts at which HIV-1 virus transfer occurs.