N-linked glycosylation in the CXCR4 N-terminus inhibits binding to HIV-1 envelope glycoproteins

Virology. 2004 Jun 20;324(1):140-50. doi: 10.1016/j.virol.2004.03.005.


CXCR4 is a co-receptor along with CD4 for human immunodeficiency virus type 1 (HIV-1). We investigated the role of N-linked glycosylation in the N-terminus of CXCR4 in binding to HIV-1 gp120 envelope glycoproteins. Gp120s from CXCR4 (X4) and CCR5 (R5) using HIV-1 strains bound more efficiently to non-N-glycosylated than to N-glycosylated CXCR4 proteoliposomes in a CD4-dependent manner. Similar results were observed in binding studies using non-N-glycosylated or N-glycosylated CXCR4 expressed on cells. Mutation of the N-glycosylation site N11 in CXCR4 (N11Q-CXCR4) enhanced CD4-dependent binding of X4 and R5 gp120s and allowed more efficient entry of viruses pseudotyped with X4 or R5 HIV-1 envelope glycoproteins. However, the binding of R5 gp120 to N11Q-CXCR4 and entry of R5 HIV-1 viruses into cells expressing N11Q-CXCR4 were 20- and 100- to 1000-fold less efficient, respectively, than the levels achieved using X4 gp120 or X4 HIV-1 viruses. Binding of stromal cell-derived factor (SDF)-1alpha, the natural ligand of CXCR4, and SDF-1alpha-induced signaling were reduced by the N11Q mutation. These findings demonstrate that N-glycosylation at N11 inhibits the binding of CXCR4 to X4 and R5 HIV-1 gp120, and provide a better understanding of the structural elements of CXCR4 involved in HIV-1 Env-co-receptor interactions.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Asparagine / metabolism
  • Cell Line
  • Chemokine CXCL12
  • Chemokines, CXC / metabolism
  • Glycosylation
  • HIV Envelope Protein gp120 / metabolism*
  • HIV-1 / physiology*
  • Humans
  • Proteolipids / physiology
  • Receptors, CCR5 / metabolism
  • Receptors, CXCR4 / chemistry
  • Receptors, CXCR4 / metabolism*
  • Structure-Activity Relationship
  • Tunicamycin / pharmacology


  • CXCL12 protein, human
  • Chemokine CXCL12
  • Chemokines, CXC
  • HIV Envelope Protein gp120
  • Proteolipids
  • Receptors, CCR5
  • Receptors, CXCR4
  • proteoliposomes
  • Tunicamycin
  • Asparagine