| Structural highlights
Function
NEF_HV1A2 Factor of infectivity and pathogenicity, required for optimal virus replication. Alters numerous pathways of T-lymphocytes function and down-regulates immunity surface molecules in order to evade host defense and increase viral infectivity. Alters the functionality of other immunity cells, like dendritic cells, monocytes/macrophages and NK cells. One of the earliest and most abundantly expressed viral proteins (By similarity).[1] [2] [3] [4] [5] [6] In infected CD4(+) T-lymphocytes, down-regulates the surface MHC-I, mature MHC-II, CD4, CD28, CCR5 and CXCR4 molecules. Mediates internalization and degradation of host CD4 through the interaction of with the cytoplasmic tail of CD4, the recruitment of AP-2 (clathrin adapter protein complex 2), internalization through clathrin coated pits, and subsequent transport to endosomes and lysosomes for degradation. Diverts host MHC-I molecules to the trans-Golgi network-associated endosomal compartments by an endocytic pathway to finally target them for degradation. MHC-I down-regulation may involve AP-1 (clathrin adapter protein complex 1) or possibly Src family kinase-ZAP70/Syk-PI3K cascade recruited by PACS2. In consequence infected cells are masked for immune recognition by cytotoxic T-lymphocytes. Decreasing the number of immune receptors also prevents reinfection by more HIV particles (superinfection) (By similarity).[7] [8] [9] [10] [11] [12] Bypasses host T-cell signaling by inducing a transcriptional program nearly identical to that of anti-CD3 cell activation. Interaction with TCR-zeta chain up-regulates the Fas ligand (FasL). Increasing surface FasL molecules and decreasing surface MHC-I molecules on infected CD4(+) cells send attacking cytotoxic CD8+ T-lymphocytes into apoptosis (By similarity).[13] [14] [15] [16] [17] [18] Plays a role in optimizing the host cell environment for viral replication without causing cell death by apoptosis. Protects the infected cells from apoptosis in order to keep them alive until the next virus generation is ready to strike. Inhibits the Fas and TNFR-mediated death signals by blocking MAP3K5. Interacts and decreases the half-life of p53, protecting the infected cell against p53-mediated apoptosis. Inhibits the apoptotic signals regulated by the Bcl-2 family proteins through the formation of a Nef/PI3-kinase/PAK2 complex that leads to activation of PAK2 and induces phosphorylation of Bad (By similarity).[19] [20] [21] [22] [23] [24] Extracellular Nef protein targets CD4(+) T-lymphocytes for apoptosis by interacting with CXCR4 surface receptors (By similarity).[25] [26] [27] [28] [29] [30]
Publication Abstract from PubMed
The Nef protein of human and simian immunodeficiency viruses boosts viral pathogenicity through its interactions with host cell proteins. By combining the polyvalency of its large unstructured regions with the binding selectivity and strength of its folded core domain, Nef can associate with many different host cell proteins, thereby disrupting their functions. For example, the combination of a linear proline-rich motif and hydrophobic core domain surface allows Nef to bind tightly and specifically to SH3 domains of Src family kinases. We investigated whether the interplay between Nef's flexible regions and its core domain could allosterically influence ligand selection. We found that the flexible regions can associate with the core domain in different ways, producing distinct conformational states that alter the way in which Nef selects for SH3 domains and exposes some of its binding motifs. The ensuing crosstalk between ligands might promote functionally coherent Nef-bound protein ensembles by synergizing certain subsets of ligands while excluding others. We also combined proteomic and bioinformatics analyses to identify human proteins that select SH3 domains in the same way as Nef. We found that only 3% of clones from a whole-human fetal library displayed Nef-like SH3 selectivity. However, in most cases, this selectivity appears to be achieved by a canonical linear interaction rather than by a Nef-like 'tertiary' interaction. Our analysis supports the contention that Nef's mode of hijacking SH3 domains is a virus-specific adaptation with no or very few cellular counterparts. Thus, the Nef tertiary binding surface is a promising virus-specific drug target.
Synergy and allostery in ligand binding by HIV-1 Nef.,Aldehaiman A, Momin AA, Restouin A, Wang L, Shi X, Aljedani S, Opi S, Lugari A, Shahul Hameed UF, Ponchon L, Morelli X, Huang M, Dumas C, Collette Y, Arold ST Biochem J. 2021 Apr 30;478(8):1525-1545. doi: 10.1042/BCJ20201002. PMID:33787846[31]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Briggs SD, Sharkey M, Stevenson M, Smithgall TE. SH3-mediated Hck tyrosine kinase activation and fibroblast transformation by the Nef protein of HIV-1. J Biol Chem. 1997 Jul 18;272(29):17899-902. PMID:9218412
- ↑ Xu XN, Laffert B, Screaton GR, Kraft M, Wolf D, Kolanus W, Mongkolsapay J, McMichael AJ, Baur AS. Induction of Fas ligand expression by HIV involves the interaction of Nef with the T cell receptor zeta chain. J Exp Med. 1999 May 3;189(9):1489-96. PMID:10224289
- ↑ Kim YH, Chang SH, Kwon JH, Rhee SS. HIV-1 Nef plays an essential role in two independent processes in CD4 down-regulation: dissociation of the CD4-p56(lck) complex and targeting of CD4 to lysosomes. Virology. 1999 Apr 25;257(1):208-19. PMID:10208934 doi:S0042-6822(99)99642-3
- ↑ Arora VK, Molina RP, Foster JL, Blakemore JL, Chernoff J, Fredericksen BL, Garcia JV. Lentivirus Nef specifically activates Pak2. J Virol. 2000 Dec;74(23):11081-7. PMID:11070003
- ↑ Simmons A, Aluvihare V, McMichael A. Nef triggers a transcriptional program in T cells imitating single-signal T cell activation and inducing HIV virulence mediators. Immunity. 2001 Jun;14(6):763-77. PMID:11420046
- ↑ Wolf D, Witte V, Laffert B, Blume K, Stromer E, Trapp S, d'Aloja P, Schurmann A, Baur AS. HIV-1 Nef associated PAK and PI3-kinases stimulate Akt-independent Bad-phosphorylation to induce anti-apoptotic signals. Nat Med. 2001 Nov;7(11):1217-24. PMID:11689886 doi:10.1038/nm1101-1217
- ↑ Briggs SD, Sharkey M, Stevenson M, Smithgall TE. SH3-mediated Hck tyrosine kinase activation and fibroblast transformation by the Nef protein of HIV-1. J Biol Chem. 1997 Jul 18;272(29):17899-902. PMID:9218412
- ↑ Xu XN, Laffert B, Screaton GR, Kraft M, Wolf D, Kolanus W, Mongkolsapay J, McMichael AJ, Baur AS. Induction of Fas ligand expression by HIV involves the interaction of Nef with the T cell receptor zeta chain. J Exp Med. 1999 May 3;189(9):1489-96. PMID:10224289
- ↑ Kim YH, Chang SH, Kwon JH, Rhee SS. HIV-1 Nef plays an essential role in two independent processes in CD4 down-regulation: dissociation of the CD4-p56(lck) complex and targeting of CD4 to lysosomes. Virology. 1999 Apr 25;257(1):208-19. PMID:10208934 doi:S0042-6822(99)99642-3
- ↑ Arora VK, Molina RP, Foster JL, Blakemore JL, Chernoff J, Fredericksen BL, Garcia JV. Lentivirus Nef specifically activates Pak2. J Virol. 2000 Dec;74(23):11081-7. PMID:11070003
- ↑ Simmons A, Aluvihare V, McMichael A. Nef triggers a transcriptional program in T cells imitating single-signal T cell activation and inducing HIV virulence mediators. Immunity. 2001 Jun;14(6):763-77. PMID:11420046
- ↑ Wolf D, Witte V, Laffert B, Blume K, Stromer E, Trapp S, d'Aloja P, Schurmann A, Baur AS. HIV-1 Nef associated PAK and PI3-kinases stimulate Akt-independent Bad-phosphorylation to induce anti-apoptotic signals. Nat Med. 2001 Nov;7(11):1217-24. PMID:11689886 doi:10.1038/nm1101-1217
- ↑ Briggs SD, Sharkey M, Stevenson M, Smithgall TE. SH3-mediated Hck tyrosine kinase activation and fibroblast transformation by the Nef protein of HIV-1. J Biol Chem. 1997 Jul 18;272(29):17899-902. PMID:9218412
- ↑ Xu XN, Laffert B, Screaton GR, Kraft M, Wolf D, Kolanus W, Mongkolsapay J, McMichael AJ, Baur AS. Induction of Fas ligand expression by HIV involves the interaction of Nef with the T cell receptor zeta chain. J Exp Med. 1999 May 3;189(9):1489-96. PMID:10224289
- ↑ Kim YH, Chang SH, Kwon JH, Rhee SS. HIV-1 Nef plays an essential role in two independent processes in CD4 down-regulation: dissociation of the CD4-p56(lck) complex and targeting of CD4 to lysosomes. Virology. 1999 Apr 25;257(1):208-19. PMID:10208934 doi:S0042-6822(99)99642-3
- ↑ Arora VK, Molina RP, Foster JL, Blakemore JL, Chernoff J, Fredericksen BL, Garcia JV. Lentivirus Nef specifically activates Pak2. J Virol. 2000 Dec;74(23):11081-7. PMID:11070003
- ↑ Simmons A, Aluvihare V, McMichael A. Nef triggers a transcriptional program in T cells imitating single-signal T cell activation and inducing HIV virulence mediators. Immunity. 2001 Jun;14(6):763-77. PMID:11420046
- ↑ Wolf D, Witte V, Laffert B, Blume K, Stromer E, Trapp S, d'Aloja P, Schurmann A, Baur AS. HIV-1 Nef associated PAK and PI3-kinases stimulate Akt-independent Bad-phosphorylation to induce anti-apoptotic signals. Nat Med. 2001 Nov;7(11):1217-24. PMID:11689886 doi:10.1038/nm1101-1217
- ↑ Briggs SD, Sharkey M, Stevenson M, Smithgall TE. SH3-mediated Hck tyrosine kinase activation and fibroblast transformation by the Nef protein of HIV-1. J Biol Chem. 1997 Jul 18;272(29):17899-902. PMID:9218412
- ↑ Xu XN, Laffert B, Screaton GR, Kraft M, Wolf D, Kolanus W, Mongkolsapay J, McMichael AJ, Baur AS. Induction of Fas ligand expression by HIV involves the interaction of Nef with the T cell receptor zeta chain. J Exp Med. 1999 May 3;189(9):1489-96. PMID:10224289
- ↑ Kim YH, Chang SH, Kwon JH, Rhee SS. HIV-1 Nef plays an essential role in two independent processes in CD4 down-regulation: dissociation of the CD4-p56(lck) complex and targeting of CD4 to lysosomes. Virology. 1999 Apr 25;257(1):208-19. PMID:10208934 doi:S0042-6822(99)99642-3
- ↑ Arora VK, Molina RP, Foster JL, Blakemore JL, Chernoff J, Fredericksen BL, Garcia JV. Lentivirus Nef specifically activates Pak2. J Virol. 2000 Dec;74(23):11081-7. PMID:11070003
- ↑ Simmons A, Aluvihare V, McMichael A. Nef triggers a transcriptional program in T cells imitating single-signal T cell activation and inducing HIV virulence mediators. Immunity. 2001 Jun;14(6):763-77. PMID:11420046
- ↑ Wolf D, Witte V, Laffert B, Blume K, Stromer E, Trapp S, d'Aloja P, Schurmann A, Baur AS. HIV-1 Nef associated PAK and PI3-kinases stimulate Akt-independent Bad-phosphorylation to induce anti-apoptotic signals. Nat Med. 2001 Nov;7(11):1217-24. PMID:11689886 doi:10.1038/nm1101-1217
- ↑ Briggs SD, Sharkey M, Stevenson M, Smithgall TE. SH3-mediated Hck tyrosine kinase activation and fibroblast transformation by the Nef protein of HIV-1. J Biol Chem. 1997 Jul 18;272(29):17899-902. PMID:9218412
- ↑ Xu XN, Laffert B, Screaton GR, Kraft M, Wolf D, Kolanus W, Mongkolsapay J, McMichael AJ, Baur AS. Induction of Fas ligand expression by HIV involves the interaction of Nef with the T cell receptor zeta chain. J Exp Med. 1999 May 3;189(9):1489-96. PMID:10224289
- ↑ Kim YH, Chang SH, Kwon JH, Rhee SS. HIV-1 Nef plays an essential role in two independent processes in CD4 down-regulation: dissociation of the CD4-p56(lck) complex and targeting of CD4 to lysosomes. Virology. 1999 Apr 25;257(1):208-19. PMID:10208934 doi:S0042-6822(99)99642-3
- ↑ Arora VK, Molina RP, Foster JL, Blakemore JL, Chernoff J, Fredericksen BL, Garcia JV. Lentivirus Nef specifically activates Pak2. J Virol. 2000 Dec;74(23):11081-7. PMID:11070003
- ↑ Simmons A, Aluvihare V, McMichael A. Nef triggers a transcriptional program in T cells imitating single-signal T cell activation and inducing HIV virulence mediators. Immunity. 2001 Jun;14(6):763-77. PMID:11420046
- ↑ Wolf D, Witte V, Laffert B, Blume K, Stromer E, Trapp S, d'Aloja P, Schurmann A, Baur AS. HIV-1 Nef associated PAK and PI3-kinases stimulate Akt-independent Bad-phosphorylation to induce anti-apoptotic signals. Nat Med. 2001 Nov;7(11):1217-24. PMID:11689886 doi:10.1038/nm1101-1217
- ↑ Aldehaiman A, Momin AA, Restouin A, Wang L, Shi X, Aljedani S, Opi S, Lugari A, Shahul Hameed UF, Ponchon L, Morelli X, Huang M, Dumas C, Collette Y, Arold ST. Synergy and allostery in ligand binding by HIV-1 Nef. Biochem J. 2021 Apr 30;478(8):1525-1545. doi: 10.1042/BCJ20201002. PMID:33787846 doi:http://dx.doi.org/10.1042/BCJ20201002
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