3rbb | pdb_00003rbb

HIV-1 NEF protein in complex with engineered HCK SH3 domain

spinqualitylabelsall models 3rbb, resolution 2.35Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3rbb is a 4 chain structure with sequence from Hiv-1 and Human. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: EDO Related: 1efn, 1avz, 2nef, 3rea, 3reb Gene: HIV-1 Nef, nef (HIV-1), HCK (HUMAN) Activity: Non-specific protein-tyrosine kinase, with EC number 2.7.10.2 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Disease [HCK_HUMAN] Note=Aberrant activation of HCK by HIV-1 protein Nef enhances HIV-1 replication and contributes to HIV-1 pathogenicity. Note=Aberrant activation of HCK, e.g. by the BCR-ABL fusion protein, promotes cancer cell proliferation. 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). 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). 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). 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). Extracellular Nef protein targets CD4(+) T-lymphocytes for apoptosis by interacting with CXCR4 surface receptors (By similarity). [HCK_HUMAN] Non-receptor tyrosine-protein kinase found in hematopoietic cells that transmits signals from cell surface receptors and plays an important role in the regulation of innate immune responses, including neutrophil, monocyte, macrophage and mast cell functions, phagocytosis, cell survival and proliferation, cell adhesion and migration. Acts downstream of receptors that bind the Fc region of immunoglobulins, such as FCGR1A and FCGR2A, but also CSF3R, PLAUR, the receptors for IFNG, IL2, IL6 and IL8, and integrins, such as ITGB1 and ITGB2. During the phagocytic process, mediates mobilization of secretory lysosomes, degranulation, and activation of NADPH oxidase to bring about the respiratory burst. Plays a role in the release of inflammatory molecules. Promotes reorganization of the actin cytoskeleton and actin polymerization, formation of podosomes and cell protrusions. Inhibits TP73-mediated transcription activation and TP73-mediated apoptosis. Phosphorylates CBL in response to activation of immunoglobulin gamma Fc region receptors. Phosphorylates ADAM15, BCR, ELMO1, FCGR2A, GAB1, GAB2, RAPGEF1, STAT5B, TP73, VAV1 and WAS. Publication Abstract from PubMed The HIV-1 Nef protein is a pathogenicity factor required for effective progression to AIDS, which modulates host cell signaling pathways and T cell receptor internalization. We have determined the crystal structure of Nef, allele SF2, in complex with an engineered SH3 domain of human Hck showing unnaturally tight binding and inhibitory potential towards Nef. This complex provides the most complete Nef structure described today, and explains the structural basis of the high affinity of this interaction. Intriguingly, the 33-residue C-terminal flexible loop is resolved in the structure by its interactions with a highly conserved hydrophobic groove on the core domain of an adjacent Nef molecule. The loop mediates the interaction of Nef with the cellular adaptor protein machinery for the stimulated internalization of surface receptors. The endocytic dileucine based sorting motif is exposed at the tip of the acidic loop, giving the myristoylated Nef protein a distinctly dipolar character. The intermolecular domain assembly of Nef provides insights into a possible regulation mechanism for cargo trafficking. Conformation of the dileucine based sorting motif in HIV-1 Nef revealed by intermolecular domain assembly.,Horenkamp FA, Breuer S, Schulte A, Lulf S, Weyand M, Saksela K, Geyer M Traffic. 2011 Apr 7. doi: 10.1111/j.1600-0854.2011.01205.x. PMID:21477083 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Tyrosine kinase

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