. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . "Nef/Hck complex recruits and phosphorylates the tyrosine kinase ZAP-70, which binds class I PI3K to trigger MHC-I downregulation in primary CD4+ T cells" . "Protective HLA alleles have a true preference for HIV-1 Gag protein, while non-protective HLA alleles preferentially target HIV-1 Nef" . "HIV-1 Nef downregulates the expression of MHC-I at the surface of lymphoid, monocytic and epithelial cells, causing MHC-I molecules to be rapidly internalized, accumulated in endosomal vesicles and degraded" . "Four glutamic acids from position 62 to 65 in the SH3 domain of HIV-1 Nef bind to the cytoplasmic tail at position 320Y of MHC-I, and are required for the Nef-mediated downregulation of MHC-I from the cell surface" . "HIV-1 Nef-induced downregulation of MHC-I expression and MHC-I targeting to the trans-Golgi network (TGN) require the binding of Nef to PACS-1, a molecule that controls the TGN localization of the cellular protein furin" . "HIV-1 Nef downregulates expression of MHC-I by blocking transport of MHC-I molecules to the cell surface through a mechanism that requires phosphoinositide 3-kinase (PI 3-kinase) activity" . "Deletion of the 19 N-terminal amino acids including the myristoylation signal from HIV-1 Nef inhibits both MHC-I and CD4 downregulation while preserving most CTL, T-helper and B-cell epitopes" . "In promonocytic cells, Nef/Hck recruits the ZAP-70 homolog Syk to downregulate MHC-I" . "HIV-1 Nef-mediated downregulation of MHC-I requires Nef motif EEEE(65)-dependent binding to the sorting protein PACS-2, which targets Nef to the paranuclear region and enables Nef PXXP(75) to bind and activate a trans-Golgi network localized Src kinase" . "Double (W13A/V16R) and triple (W13A/V16R/M20A) substitution mutants of HIV-1 Nef fail to downregulate MHC-I" . "The HIV-1 Nef highly conserved valine-glycine-phenylalanine amino acid triplet (VGF) motif, which links the acidic cluster and the proline-rich motif, is important for downregulation of CXCR4 and MHC-I" . "HIV-1 Nef with A84D, Y135F, and G140R mutation impairs to its ability to downregulate MHC-I" . "Asp327 and Tyr320 of MHC-I, Asp123 of Nef, and Arg225, Arg393, Lys396, Arg211, and Arg246 of mu 1 are involved in a crucial three-way electrostatic network, which results in the Nef-MHC-I CD-mu 1 complex formation" . "HLA-A2 molecules with HLA-A cytoplasmic domains are more downregulated by HIV-1 Nef than those with HLA-B domains. There is no downregulation of HLA-A2 with HLA-C cytoplasmic domains by Nef" . "Interaction of HIV-1 Nef with the mu subunit of AP adaptor complexes requires the recognition of tyrosine-based sorting signals, which likely facilitates the connection between MHC I and the clathrin-dependent sorting machinery" . "A methionine residue at amino acid 20 in the alpha-helix domain is required for the ability of HIV-1 Nef to downregulate MHC-I expression but not for the downregulation of CD4" . "Amino acid residue Y320 in the MHC-I cytoplasmic domain and residues E62-65 and P78 in HIV-1 Nef are required for interaction with the mu subunit of AP-1" . "MHC-I is found in the Rab7(+) vesicles and is targeted for degradation via the activity of the Nef-interacting protein, beta-COP" . "downregulates" . "interacts with" . "binds" . "complexes with" . "degrades" . "targeted by" . .