HIV-1 Nef dimers short-circuit immune receptor signaling by activating Tec-family kinases at the host cell membrane

J Biol Chem. 2020 Apr 10;295(15):5163-5174. doi: 10.1074/jbc.RA120.012536. Epub 2020 Mar 6.


The HIV-1 virulence factor Nef promotes high-titer viral replication, immune escape, and pathogenicity. Nef interacts with interleukin-2-inducible T-cell kinase (Itk) and Bruton's tyrosine kinase (Btk), two Tec-family kinases expressed in HIV-1 target cells (CD4 T cells and macrophages, respectively). Using a cell-based bimolecular fluorescence complementation assay, here we demonstrate that Nef recruits both Itk and Btk to the cell membrane and induces constitutive kinase activation in transfected 293T cells. Nef homodimerization-defective mutants retained their interaction with both kinases but failed to induce activation, supporting a role for Nef homodimer formation in the activation mechanism. HIV-1 infection up-regulates endogenous Itk activity in SupT1 T cells and donor-derived peripheral blood mononuclear cells. However, HIV-1 strains expressing Nef variants with mutations in the dimerization interface replicated poorly and were significantly attenuated in Itk activation. We conclude that direct activation of Itk and Btk by Nef at the membrane in HIV-infected cells may override normal immune receptor control of Tec-family kinase activity to enhance the viral life cycle.

Keywords: Bruton's tyrosine kinase (BTK); HIV-1 Nef; T-cell receptor (TCR); Tec-family kinase; bimolecular fluorescence complementation (BiFC); dimerization; human immunodeficiency virus (HIV); infectious disease; interleukin-2-inducible kinase (ITK); protein kinase; protein–protein interaction; signal transduction.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Agammaglobulinaemia Tyrosine Kinase / genetics
  • Agammaglobulinaemia Tyrosine Kinase / metabolism*
  • Antiviral Agents / pharmacology
  • Cell Membrane / metabolism*
  • HIV Infections / immunology*
  • HIV Infections / metabolism
  • HIV Infections / virology
  • HIV-1 / immunology*
  • Humans
  • Leukocytes, Mononuclear / drug effects
  • Leukocytes, Mononuclear / immunology
  • Leukocytes, Mononuclear / virology
  • Protein Multimerization
  • Protein-Tyrosine Kinases / genetics
  • Protein-Tyrosine Kinases / metabolism*
  • Signal Transduction
  • Small Molecule Libraries / pharmacology
  • T-Lymphocytes / drug effects
  • T-Lymphocytes / immunology
  • T-Lymphocytes / virology
  • Virus Replication
  • nef Gene Products, Human Immunodeficiency Virus / chemistry*
  • nef Gene Products, Human Immunodeficiency Virus / genetics
  • nef Gene Products, Human Immunodeficiency Virus / metabolism


  • Antiviral Agents
  • Small Molecule Libraries
  • nef Gene Products, Human Immunodeficiency Virus
  • nef protein, Human immunodeficiency virus 1
  • Tec protein-tyrosine kinase
  • Protein-Tyrosine Kinases
  • Agammaglobulinaemia Tyrosine Kinase
  • BTK protein, human
  • emt protein-tyrosine kinase

Associated data

  • PDB/1EFN
  • PDB/4U5W