Filamin-A regulates actin-dependent clustering of HIV receptors

Nat Cell Biol. 2007 Jul;9(7):838-46. doi: 10.1038/ncb1610. Epub 2007 Jun 17.

Abstract

Human immunodeficiency virus (HIV)-1 infection requires envelope (Env) glycoprotein gp120-induced clustering of CD4 and coreceptors (CCR5 or CXCR4) on the cell surface; this enables Env gp41 activation and formation of a complex that mediates fusion between Env-containing and target-cell membranes. Kinetic studies show that viral receptors are actively transported to the Env-receptor interface in a process that depends on plasma membrane composition and the actin cytoskeleton. The mechanisms by which HIV-1 induces F-actin rearrangement in the target cell remain largely unknown. Here, we show that CD4 and the coreceptors interact with the actin-binding protein filamin-A, whose binding to HIV-1 receptors regulates their clustering on the cell surface. We found that gp120 binding to cell receptors induces transient cofilin-phosphorylation inactivation through a RhoA-ROCK-dependent mechanism. Blockade of filamin-A interaction with CD4 and/or coreceptors inhibits gp120-induced RhoA activation and cofilin inactivation. Our results thus identify filamin-A as an adaptor protein that links HIV-1 receptors to the actin cytoskeleton remodelling machinery, which may facilitate virus infection.

Publication types

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

MeSH terms

  • Actin Depolymerizing Factors / metabolism
  • Actins / physiology*
  • Amino Acid Sequence
  • CD4 Antigens / metabolism*
  • Cell Line
  • Contractile Proteins / physiology*
  • Filamins
  • HIV Envelope Protein gp120 / metabolism*
  • HIV-1 / metabolism
  • HIV-1 / physiology*
  • Humans
  • Microfilament Proteins / physiology*
  • Models, Molecular
  • Molecular Sequence Data
  • Receptors, CCR5 / metabolism
  • Receptors, CXCR4 / metabolism
  • rhoA GTP-Binding Protein / metabolism

Substances

  • Actin Depolymerizing Factors
  • Actins
  • CD4 Antigens
  • Contractile Proteins
  • Filamins
  • HIV Envelope Protein gp120
  • Microfilament Proteins
  • Receptors, CCR5
  • Receptors, CXCR4
  • rhoA GTP-Binding Protein