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

Jimmy D. Dikeakos, Katelyn M. Atkins, Laurel Thomas, Lori Emert-Sedlak, In Ja L. Byeon, Jinwon Jung, Jinwoo Ahn, Matthew D. Wortman, Ben Kukull, Masumichi Saito, Hirokazu Koizumi, Danielle M. Williamson, Masateru Hiyoshi, Eric Barklis, Masafumi Takiguchi, Shinya Suzu, Angela M. Gronenborn, Thomas E. Smithgall, Gary Thomas

Research output: Contribution to journalArticlepeer-review

58 Scopus citations


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.

Original languageEnglish (US)
Pages (from-to)3279-3292
Number of pages14
JournalMolecular biology of the cell
Issue number19
StatePublished - Oct 1 2010

ASJC Scopus subject areas

  • Molecular Biology
  • Cell Biology


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