Human immunodeficiency virus type 1 envelope gp120-induced partial T-cell receptor signaling creates an F-actin-depleted zone in the virological synapse

J Virol. 2009 Nov;83(21):11341-55. doi: 10.1128/JVI.01440-09. Epub 2009 Aug 26.

Abstract

Cell-to-cell transmission of human immunodeficiency virus type 1 (HIV-1) occurs via a virological synapse (VS), a tight cell-cell junction formed between HIV-infected cells and target cells in which the HIV-1-infected cell polarizes and releases virions toward the noninfected target cell in a gp120- and intercellular adhesion molecule 1 (ICAM-1)-dependent process. The response of the target cell has been less studied. We utilized supported planar bilayers presenting gp120 and ICAM-1 as a reductionist model for the infected-cell membrane and investigated its effect on the target CD4 T cell. This study shows that HIV-1 gp120 interaction with its receptors is initially organized into microclusters that undergo F-actin-dependent consolidation into a central supramolecular activation complex (cSMAC). Src kinases are active in both gp120 microclusters and in the VS cSMAC. The early T-cell receptor (TCR) signaling machinery is partially activated at the VS, and signaling does not propagate to trigger Ca(2+) elevation or increase CD69 expression. However, these partial TCR signals act locally to create an F-actin-depleted zone. We propose a model in which the F-actin-depleted zone formed within the target CD4 T cell enhances the reception of virions by releasing the physical barrier for HIV-1 entry and facilitating postentry events.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Actins / metabolism*
  • Adaptor Proteins, Signal Transducing / metabolism
  • CD3 Complex / metabolism
  • CD4-Positive T-Lymphocytes / cytology
  • CD4-Positive T-Lymphocytes / metabolism*
  • Cell Membrane / metabolism
  • Cells, Cultured
  • Enzyme Activation
  • HIV Envelope Protein gp120 / metabolism*
  • HIV-1 / physiology*
  • Humans
  • Intercellular Adhesion Molecule-1 / immunology
  • Intercellular Junctions / metabolism*
  • Lymphocyte Specific Protein Tyrosine Kinase p56(lck) / metabolism
  • Membrane Proteins / metabolism
  • Phospholipase C gamma / metabolism
  • Proto-Oncogene Proteins c-akt / metabolism
  • Proto-Oncogene Proteins c-fyn / metabolism
  • Receptors, Antigen, T-Cell / metabolism*
  • Signal Transduction*
  • Virus Internalization*
  • ZAP-70 Protein-Tyrosine Kinase / metabolism

Substances

  • Actins
  • Adaptor Proteins, Signal Transducing
  • CD3 Complex
  • HIV Envelope Protein gp120
  • LAT protein, human
  • Membrane Proteins
  • Receptors, Antigen, T-Cell
  • Intercellular Adhesion Molecule-1
  • Lymphocyte Specific Protein Tyrosine Kinase p56(lck)
  • Proto-Oncogene Proteins c-fyn
  • ZAP-70 Protein-Tyrosine Kinase
  • ZAP70 protein, human
  • Proto-Oncogene Proteins c-akt
  • Phospholipase C gamma