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].
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.
Institute of Microbiology, University of Lausanne, CH-1011 Lausanne, Switzerland.
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S
Wyss
C
C
Berlioz-Torrent
M
M
Boge
G
G
Blot
S
S
Höning
R
R
Benarous
M
M
Thali
D033981:Adaptor Protein Complex delta Subunits; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D015967:Gene Expression Regulation, Viral; D015686:Gene Products, env / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D015752:Genes, env; D015497:HIV-1 / Q000737:chemistry / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D007930:Leucine / Q000737:chemistry / Q000235:genetics; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D009154:Mutation; D015398:Signal Transduction; D013347:Subcellular Fractions / Q000378:metabolism; D014162:Transfection
D033981:Adaptor Protein Complex delta Subunits; D015686:Gene Products, env; D008565:Membrane Proteins; D007930:Leucine