Small molecule inhibition of HIV-1-induced MHC-I down-regulation identifies a temporally regulated switch in Nef action

Mol Biol Cell. 2010 Oct 1;21(19):3279-92. doi: 10.1091/mbc.E10-05-0470. Epub 2010 Aug 11.

Abstract

HIV-1 Nef triggers down-regulation of cell-surface MHC-I by assembling a Src family kinase (SFK)-ZAP-70/Syk-PI3K cascade. Here, we report that chemical disruption of the Nef-SFK interaction with the small molecule inhibitor 2c blocks assembly of the multi-kinase complex and represses HIV-1-mediated MHC-I down-regulation in primary CD4(+) T-cells. 2c did not interfere with the PACS-2-dependent trafficking of Nef required for the Nef-SFK interaction or the AP-1 and PACS-1-dependent sequestering of internalized MHC-I, suggesting the inhibitor specifically interfered with the Nef-SFK interaction required for triggering MHC-I down-regulation. Transport studies revealed Nef directs a highly regulated program to down-regulate MHC-I in primary CD4(+) T-cells. During the first two days after infection, Nef assembles the 2c-sensitive multi-kinase complex to trigger down-regulation of cell-surface MHC-I. By three days postinfection Nef switches to a stoichiometric mode that prevents surface delivery of newly synthesized MHC-I. Pharmacologic inhibition of the multi-kinase cascade prevents the Nef-dependent block in MHC-I transport, suggesting the signaling and stoichiometric modes are causally linked. Together, these studies resolve the seemingly controversial models that describe Nef-induced MHC-I down-regulation and provide new insights into the mechanism of Nef action.

Publication types

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

MeSH terms

  • CD4-Positive T-Lymphocytes / drug effects
  • CD4-Positive T-Lymphocytes / enzymology
  • CD4-Positive T-Lymphocytes / virology
  • Cell Line
  • Down-Regulation / drug effects*
  • Endocytosis / drug effects
  • HIV-1 / drug effects*
  • Histocompatibility Antigens Class I / metabolism*
  • Humans
  • Multienzyme Complexes / metabolism
  • PTEN Phosphohydrolase / metabolism
  • Phosphatidylinositol 3-Kinases / metabolism
  • Protein Binding / drug effects
  • Protein Transport / drug effects
  • Signal Transduction / drug effects
  • Small Molecule Libraries / pharmacology*
  • Time Factors
  • Transcription Factor AP-1 / metabolism
  • Vesicular Transport Proteins / metabolism
  • nef Gene Products, Human Immunodeficiency Virus / metabolism*
  • src-Family Kinases / metabolism

Substances

  • Histocompatibility Antigens Class I
  • Multienzyme Complexes
  • PACS1 protein, human
  • Small Molecule Libraries
  • Transcription Factor AP-1
  • Vesicular Transport Proteins
  • nef Gene Products, Human Immunodeficiency Virus
  • Phosphatidylinositol 3-Kinases
  • src-Family Kinases
  • PTEN Phosphohydrolase
  • PTEN protein, human