At the cellular level, Nef has been ascribed multiple functions, of which the best characterized and most critical for pathogenesis is the downregulation of CD4 from the surface of infected cells Guy et al. GFP was used as an indicator for transfected cells. This provides insight into the underlying reason for the unusual architecture of Nef, as a single domain protein with disproportionately large internal loops. The structure also shows that the Nef core has both a direct role in forming polar interactions with AP-2 and an indirect role in scaffolding the conformation of the central loop. Moreover, since these sites are not susceptible to rapid mutations, such drugs are less likely to encounter the problem of drug resistance. A highly concave pocket specific for the Nef interaction. The results of these analyses are represented in Figure 4 together with previously published data.

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These enzymes are the main targets for chemotherapeutic agents currently in use for the prevention and treatment of AIDS. Nef complex AP complexes function as membrane-bound, tetrameric assemblies. However, the details of the molecular contacts between Nef and the membrane surface differ Figure 8.

Von Neumann and Goldstine graphing system Notation. The N-terminus of H1 is exposed to solvent such that there would be nothing to impede contact of the myristoylated N-terminus with the membrane.

Myristoylation allows recruitment of Nef from the cytosol to the inner leaflet of the plasma membrane Yu and Felsted, while the loop engages the clathrin-associated adaptor protein 2 AP-2 complex Jin et al.


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C Detailed ribbon model of Nef orange with the secondary structures indicated. Additional information Competing interests The cc099 declare that no competing interests exist.

Direct in vitro binding of full-length human immunodeficiency virus type 1 Nef protein to CD4 cytoplasmic domain. Molecular Biology of the Cell.

How HIV-1 Nef hijacks the AP-2 clathrin adaptor to downregulate CD4

This architecture gives Nef an exceptional degree of plasticity, allowing multiple functions to be encoded within a relatively small structure. X-ray crystallography Lee et al. Residues involved in both direct and indirect interactions are required for the binding of Nef to AP-2 and for downregulation of CD4. This suggests that multivalent interactions between Nef, CD4, and AP-2 likely drive cooperativity in the formation of the ternary complex.

Although the current structure does not include CD4, can akke authors speculate further on how binding to CD4 might ake this affect?

In an effort to prevent and treat AIDS, researchers have worked to understand the HIV-1 genome and have developed medicines that target the enzymatic activity of viral proteins involved in aikr replication. Downregulation of CD4 by human immunodeficiency virus type 1 Nef is dependent on clathrin and involves direct interaction of Nef with the AP2 clathrin adaptor. MilnerTofte and Harper. We performed additional mutagenesis to test for the functional importance of residues that were newly identified by the v099 determination Figures 5 and 6.

Combination therapies with these agents have dramatically reduced HIV-1 transmission as well as Aikf morbidity akie mortality. The New England Journal of Medicine. The consensus docking of the AP The protein was eluted with 0. This reduces the ability of the T cells to activate the aikd system and allows the virus to spread.


David Turner at University of Kent. AP-2 complex interacts with the cytosolic tail of CD4, leading to the cooperative assembly of a tripartite Nef: The PyMOL molecular graphics system. James Gosling at Sun Microsystems. An edited version of the letter sent to the authors after peer review is shown, indicating the substantive concerns or comments; minor concerns are not usually shown. This region has no known interactions with physiological cargoes. Adaptors for clathrin coats: The structure shows that all of these residues are well ordered in the complex, in contrast to all previous structures of Nef—effector complexes.

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The map is contoured at 2. Moreover, since these sites are not susceptible to rapid ai,e, such drugs are less likely to encounter the problem of drug resistance.

The solution structure of HIV-1 Nef reveals an unexpected fold and permits delineation of the binding surface for the SH3 domain of Hck tyrosine protein kinase. Yeast 3-hybrid analysis Y3H analysis was performed as previously described Chaudhuri et al.