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Two elements target SIV Nef to the AP‐2 clathrin adaptor complex, but only one is required for the induction of CD4 endocytosis
Author(s) -
Lock Martin,
Greenberg Michael E.,
Iafrate A. John,
Swigut Tomek,
Muench Jan,
Kirchhoff Frank,
Shohdy Nadim,
Skowronski Jacek
Publication year - 1999
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/18.10.2722
Subject(s) - biology , endocytosis , clathrin , signal transducing adaptor protein , microbiology and biotechnology , virology , genetics , signal transduction , receptor
The simian immunodeficiency virus (SIV) and human immunodeficiency virus type 1 (HIV‐1) Nef proteins induce the endocytosis of CD4 and class I MHC molecules. Here we show that SIV Nef interacts with the AP‐2 adaptor complex via two elements located in the N‐terminal region of the Nef molecule, but only the N‐distal element is required to induce CD4 endocytosis. This N‐distal AP‐2 targeting element contains no canonical endocytic signals and probably contacts the AP‐2 complex via a novel interaction surface. The data support a model where SIV Nef induces CD4 endocytosis by promoting the normal interactions between the di‐leucine sorting signal in the CD4 cytoplasmic domain and AP‐2, but does not substitute for the CD4–AP‐2 adaptor interaction. Neither element is important for the induction of class I MHC endocytosis, thus indicating that different mechanisms underlie the induction of class I MHC and CD4 endocytosis by Nef. In contrast to SIV Nef, HIV‐1 Nef interacts with AP‐2 via a surface containing a di‐leucine endocytosis signal in the C‐terminal disordered loop of Nef. The fact that genetic selection maintains similar molecular interactions via different surfaces in SIV and HIV‐1 Nef proteins indicates that these interactions have critical roles for the viral life cycle in vivo .