Nucleocapsid promotes localization of HIV-1 gag to uropods that participate in virological synapses between T cells.
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.
Cellular and Molecular Biology Program, University of Michigan Medical School, Ann Arbor, Michigan, United States of America.
G Nicholas
GN
Llewellyn
Ian B
IB
Hogue
Jonathan R
JR
Grover
Akira
A
Ono
D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D002462:Cell Membrane / Q000821:virology; D016764:Cell Polarity / Q000187:drug effects / Q000276:immunology; D022081:Cell Surface Extensions / Q000276:immunology / Q000378:metabolism*; D002478:Cells, Cultured; D005455:Fluorescent Antibody Technique; D015497:HIV-1 / Q000378:metabolism / Q000502:physiology; D006801:Humans; D054992:Immunological Synapses / Q000378:metabolism / Q000821:virology*; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D021962:Membrane Microdomains / Q000187:drug effects / Q000378:metabolism; D008954:Models, Biological; D009219:Myosin-Light-Chain Kinase / Q000037:antagonists & inhibitors; D019251:Nucleocapsid / Q000502:physiology*; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D013601:T-Lymphocytes / Q000276:immunology / Q000378:metabolism* / Q000502:physiology / Q000821:virology; D014018:Tissue Distribution; D054301:gag Gene Products, Human Immunodeficiency Virus / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
D001426:Bacterial Proteins; D008164:Luminescent Proteins; D047428:Protein Kinase Inhibitors; D011993:Recombinant Fusion Proteins; D054301:gag Gene Products, Human Immunodeficiency Virus; C054562:yellow fluorescent protein, Bacteria; D009219:Myosin-Light-Chain Kinase