The highly conserved C-terminal dileucine motif in the cytosolic domain of the human immunodeficiency virus type 1 envelope glycoprotein is critical for its association with the AP-1 clathrin adaptor [correction of adapter]

J Virol. 2001 Mar;75(6):2982-92. doi: 10.1128/JVI.75.6.2982-2992.2001.

Abstract

Short amino acid sequences in the cytosolic domains of transmembrane proteins are recognized by specialized adaptor [corrected] proteins which are part of coated vesicles utilized to transport membrane proteins between the trans-Golgi network (TGN) and the plasma membrane (forward and backward). Previously, we and others reported that the membrane-proximal tyrosine residues Y712 (human immunodeficiency virus [HIV]) and Y721 (simian immunodeficiency virus [SIV]) in the envelope glycoprotein (Env) of the primate lentiviruses are crucial for the association of Env with clathrin-associated adaptor [corrected] complex AP-2. The same tyrosine-based endocytosis motifs in the cytosolic domains (EnvCD) of transmembrane gp41 of HIV type 1 (HIV-1) and SIV, respectively, were also shown to modulate the interaction with TGN- and endosome-based clathrin-associated complex AP-1. Our findings suggested that EnvCD binding to AP-1, unlike the association of EnvCD with AP-2, is dependent largely on residues other than Y712 and Y721. Here, we tested if motifs downstream of Y712 affect HIV-1 EnvCD-AP-1 binding and Env trafficking. Mutational analysis revealed that the C-terminal leucine-based motif in Env was crucial for the recruitment of AP-1 in vitro and in Env-expressing cells. In addition to affecting Env-AP-1 association, mutations at the C terminus of Env also altered the subcellular localization of Env, suggesting that proper post-Golgi routing of Env depends on its recruitment of AP-1. Finally, the C-terminal dileucine was shown to assist the membrane-proximal Y712 motif in restricting the cell surface expression of Env.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Protein Complex delta Subunits
  • Amino Acid Motifs
  • Amino Acid Sequence
  • Gene Expression Regulation, Viral
  • Gene Products, env / chemistry*
  • Gene Products, env / genetics
  • Gene Products, env / metabolism*
  • Genes, env
  • HIV-1 / chemistry
  • HIV-1 / metabolism*
  • HeLa Cells
  • Humans
  • Leucine / chemistry
  • Leucine / genetics
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism*
  • Molecular Sequence Data
  • Mutation
  • Signal Transduction
  • Subcellular Fractions / metabolism
  • Transfection

Substances

  • Adaptor Protein Complex delta Subunits
  • Gene Products, env
  • Membrane Proteins
  • Leucine