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| | <StructureSection load='3zni' size='340' side='right'caption='[[3zni]], [[Resolution|resolution]] 2.21Å' scene=''> | | <StructureSection load='3zni' size='340' side='right'caption='[[3zni]], [[Resolution|resolution]] 2.21Å' scene=''> |
| | == Structural highlights == | | == Structural highlights == |
| - | <table><tr><td colspan='2'>[[3zni]] is a 16 chain structure with sequence from [http://en.wikipedia.org/wiki/Human Human]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3ZNI OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=3ZNI FirstGlance]. <br> | + | <table><tr><td colspan='2'>[[3zni]] is a 16 chain structure with sequence from [https://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3ZNI OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=3ZNI FirstGlance]. <br> |
| - | </td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=CA:CALCIUM+ION'>CA</scene>, <scene name='pdbligand=EDO:1,2-ETHANEDIOL'>EDO</scene>, <scene name='pdbligand=ZN:ZINC+ION'>ZN</scene></td></tr> | + | </td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 2.21Å</td></tr> |
| - | <tr id='NonStdRes'><td class="sblockLbl"><b>[[Non-Standard_Residue|NonStd Res:]]</b></td><td class="sblockDat"><scene name='pdbligand=PTR:O-PHOSPHOTYROSINE'>PTR</scene></td></tr> | + | <tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CA:CALCIUM+ION'>CA</scene>, <scene name='pdbligand=EDO:1,2-ETHANEDIOL'>EDO</scene>, <scene name='pdbligand=PTR:O-PHOSPHOTYROSINE'>PTR</scene>, <scene name='pdbligand=ZN:ZINC+ION'>ZN</scene></td></tr> |
| - | <tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[http://en.wikipedia.org/wiki/Ubiquitin--protein_ligase Ubiquitin--protein ligase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=6.3.2.19 6.3.2.19] </span></td></tr> | + | <tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=3zni FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3zni OCA], [https://pdbe.org/3zni PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=3zni RCSB], [https://www.ebi.ac.uk/pdbsum/3zni PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=3zni ProSAT]</span></td></tr> |
| - | <tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=3zni FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3zni OCA], [http://pdbe.org/3zni PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=3zni RCSB], [http://www.ebi.ac.uk/pdbsum/3zni PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=3zni ProSAT]</span></td></tr> | + | |
| | </table> | | </table> |
| - | == Disease == | |
| - | [[http://www.uniprot.org/uniprot/ZAP70_HUMAN ZAP70_HUMAN]] Defects in ZAP70 are the cause of selective T-cell defect (STCD) [MIM:[http://omim.org/entry/269840 269840]]. A form of severe combined immunodeficiency characterized by a selective absence of CD8+ T cells.<ref>PMID:8124727</ref> <ref>PMID:8202713</ref> <ref>PMID:11412303</ref> <ref>PMID:11123350</ref> <ref>PMID:18509675</ref> | |
| | == Function == | | == Function == |
| - | [[http://www.uniprot.org/uniprot/UBC_HUMAN UBC_HUMAN]] Ubiquitin exists either covalently attached to another protein, or free (unanchored). When covalently bound, it is conjugated to target proteins via an isopeptide bond either as a monomer (monoubiquitin), a polymer linked via different Lys residues of the ubiquitin (polyubiquitin chains) or a linear polymer linked via the initiator Met of the ubiquitin (linear polyubiquitin chains). Polyubiquitin chains, when attached to a target protein, have different functions depending on the Lys residue of the ubiquitin that is linked: Lys-6-linked may be involved in DNA repair; Lys-11-linked is involved in ERAD (endoplasmic reticulum-associated degradation) and in cell-cycle regulation; Lys-29-linked is involved in lysosomal degradation; Lys-33-linked is involved in kinase modification; Lys-48-linked is involved in protein degradation via the proteasome; Lys-63-linked is involved in endocytosis, DNA-damage responses as well as in signaling processes leading to activation of the transcription factor NF-kappa-B. Linear polymer chains formed via attachment by the initiator Met lead to cell signaling. Ubiquitin is usually conjugated to Lys residues of target proteins, however, in rare cases, conjugation to Cys or Ser residues has been observed. When polyubiquitin is free (unanchored-polyubiquitin), it also has distinct roles, such as in activation of protein kinases, and in signaling.<ref>PMID:16543144</ref> <ref>PMID:19754430</ref> [[http://www.uniprot.org/uniprot/CBLB_HUMAN CBLB_HUMAN]] E3 ubiquitin-protein ligase which accepts ubiquitin from specific E2 ubiquitin-conjugating enzymes, and transfers it to substrates, generally promoting their degradation by the proteasome. Negatively regulates TCR (T-cell receptor), BCR (B-cell receptor) and FCER1 (high affinity immunoglobulin epsilon receptor) signal transduction pathways. In naive T-cells, inhibits VAV1 activation upon TCR engagement and imposes a requirement for CD28 costimulation for proliferation and IL-2 production. Also acts by promoting PIK3R1/p85 ubiquitination, which impairs its recruitment to the TCR and subsequent activation. In activated T-cells, inhibits PLCG1 activation and calcium mobilization upon restimulation and promotes anergy. In B-cells, acts by ubiquitinating SYK and promoting its proteasomal degradation. May also be involved in EGFR ubiquitination and internalization.<ref>PMID:10022120</ref> <ref>PMID:10086340</ref> <ref>PMID:11087752</ref> <ref>PMID:11526404</ref> [[http://www.uniprot.org/uniprot/UB2D2_HUMAN UB2D2_HUMAN]] Accepts ubiquitin from the E1 complex and catalyzes its covalent attachment to other proteins. In vitro catalyzes 'Lys-48'-linked polyubiquitination. Mediates the selective degradation of short-lived and abnormal proteins. Functions in the E6/E6-AP-induced ubiquitination of p53/TP53. Mediates ubiquitination of PEX5 and autoubiquitination of STUB1 and TRAF6. Involved in the signal-induced conjugation and subsequent degradation of NFKBIA, FBXW2-mediated GCM1 ubiquitination and degradation, MDM2-dependent degradation of p53/TP53 and the activation of MAVS in the mitochondria by DDX58/RIG-I in response to viral infection. Essential for viral activation of IRF3.<ref>PMID:10329681</ref> <ref>PMID:15280377</ref> <ref>PMID:18042044</ref> <ref>PMID:18703417</ref> <ref>PMID:18359941</ref> <ref>PMID:19854139</ref> <ref>PMID:20403326</ref> <ref>PMID:20061386</ref> [[http://www.uniprot.org/uniprot/ZAP70_HUMAN ZAP70_HUMAN]] Tyrosine kinase that plays an essential role in regulation of the adaptive immune response. Regulates motility, adhesion and cytokine expression of mature T-cells, as well as thymocyte development. Contributes also to the development and activation of primary B-lymphocytes. When antigen presenting cells (APC) activate T-cell receptor (TCR), a serie of phosphorylations lead to the recruitment of ZAP70 to the doubly phosphorylated TCR component CD247/CD3Z through ITAM motif at the plasma membrane. This recruitment serves to localization to the stimulated TCR and to relieve its autoinhibited conformation. Release of ZAP70 active conformation is further stabilized by phosphorylation mediated by LCK. Subsequently, ZAP70 phosphorylates at least 2 essential adapter proteins: LAT and LCP2. In turn, a large number of signaling molecules are recruited and ultimately lead to lymphokine production, T-cell proliferation and differentiation. Furthermore, ZAP70 controls cytoskeleton modifications, adhesion and mobility of T-lymphocytes, thus ensuring correct delivery of effectors to the APC. ZAP70 is also required for TCR-CD247/CD3Z internalization and degradation through interaction with the E3 ubiquitin-protein ligase CBL and adapter proteins SLA and SLA2. Thus, ZAP70 regulates both T-cell activation switch on and switch off by modulating TCR expression at the T-cell surface. During thymocyte development, ZAP70 promotes survival and cell-cycle progression of developing thymocytes before positive selection (when cells are still CD4/CD8 double negative). Additionally, ZAP70-dependent signaling pathway may also contribute to primary B-cells formation and activation through B-cell receptor (BCR).<ref>PMID:1423621</ref> <ref>PMID:8124727</ref> <ref>PMID:8702662</ref> <ref>PMID:9489702</ref> <ref>PMID:11353765</ref> | + | [https://www.uniprot.org/uniprot/CBLB_HUMAN CBLB_HUMAN] E3 ubiquitin-protein ligase which accepts ubiquitin from specific E2 ubiquitin-conjugating enzymes, and transfers it to substrates, generally promoting their degradation by the proteasome. Negatively regulates TCR (T-cell receptor), BCR (B-cell receptor) and FCER1 (high affinity immunoglobulin epsilon receptor) signal transduction pathways. In naive T-cells, inhibits VAV1 activation upon TCR engagement and imposes a requirement for CD28 costimulation for proliferation and IL-2 production. Also acts by promoting PIK3R1/p85 ubiquitination, which impairs its recruitment to the TCR and subsequent activation. In activated T-cells, inhibits PLCG1 activation and calcium mobilization upon restimulation and promotes anergy. In B-cells, acts by ubiquitinating SYK and promoting its proteasomal degradation. May also be involved in EGFR ubiquitination and internalization.<ref>PMID:10022120</ref> <ref>PMID:10086340</ref> <ref>PMID:11087752</ref> <ref>PMID:11526404</ref> |
| | <div style="background-color:#fffaf0;"> | | <div style="background-color:#fffaf0;"> |
| | == Publication Abstract from PubMed == | | == Publication Abstract from PubMed == |
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| | | | |
| | ==See Also== | | ==See Also== |
| - | *[[Ubiquitin|Ubiquitin]] | + | *[[3D structures of ubiquitin|3D structures of ubiquitin]] |
| - | *[[Ubiquitin conjugating enzyme|Ubiquitin conjugating enzyme]] | + | *[[3D structures of ubiquitin conjugating enzyme|3D structures of ubiquitin conjugating enzyme]] |
| | == References == | | == References == |
| | <references/> | | <references/> |
| | __TOC__ | | __TOC__ |
| | </StructureSection> | | </StructureSection> |
| - | [[Category: Human]] | + | [[Category: Homo sapiens]] |
| | [[Category: Large Structures]] | | [[Category: Large Structures]] |
| - | [[Category: Ubiquitin--protein ligase]]
| + | [[Category: Buetow L]] |
| - | [[Category: Buetow, L]] | + | [[Category: Cameron K]] |
| - | [[Category: Cameron, K]] | + | [[Category: Dou H]] |
| - | [[Category: Dou, H]] | + | [[Category: Huang DT]] |
| - | [[Category: Huang, D T]] | + | [[Category: Sibbet GJ]] |
| - | [[Category: Sibbet, G J]] | + | |
| - | [[Category: Degradation]]
| + | |
| - | [[Category: Ligase]]
| + | |
| Structural highlights
Function
CBLB_HUMAN E3 ubiquitin-protein ligase which accepts ubiquitin from specific E2 ubiquitin-conjugating enzymes, and transfers it to substrates, generally promoting their degradation by the proteasome. Negatively regulates TCR (T-cell receptor), BCR (B-cell receptor) and FCER1 (high affinity immunoglobulin epsilon receptor) signal transduction pathways. In naive T-cells, inhibits VAV1 activation upon TCR engagement and imposes a requirement for CD28 costimulation for proliferation and IL-2 production. Also acts by promoting PIK3R1/p85 ubiquitination, which impairs its recruitment to the TCR and subsequent activation. In activated T-cells, inhibits PLCG1 activation and calcium mobilization upon restimulation and promotes anergy. In B-cells, acts by ubiquitinating SYK and promoting its proteasomal degradation. May also be involved in EGFR ubiquitination and internalization.[1] [2] [3] [4]
Publication Abstract from PubMed
RING E3 ligases catalyze the transfer of ubiquitin (Ub) from E2 ubiquitin-conjugating enzyme thioesterified with Ub (E2~Ub) to substrate. For RING E3 dimers, the RING domain of one subunit and tail of the second cooperate to prime Ub, but how this is accomplished by monomeric RING E3s in the absence of a tail-like component is currently unknown. Here, we present a crystal structure of a monomeric RING E3, Tyr363-phosphorylated human CBL-B, bound to a stabilized Ub-linked E2, revealing a similar mechanism in activating E2~Ub. Both pTyr363 and the pTyr363-induced element interact directly with Ub's Ile36 surface, improving the catalytic efficiency of Ub transfer by ~200-fold. Hence, interactions outside the canonical RING domain are crucial for optimizing Ub transfer in both monomeric and dimeric RING E3s. We propose that an additional non-RING Ub-priming element may be a common RING E3 feature.
Essentiality of a non-RING element in priming donor ubiquitin for catalysis by a monomeric E3.,Dou H, Buetow L, Sibbet GJ, Cameron K, Huang DT Nat Struct Mol Biol. 2013 Jul 14. doi: 10.1038/nsmb.2621. PMID:23851457[5]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Elly C, Witte S, Zhang Z, Rosnet O, Lipkowitz S, Altman A, Liu YC. Tyrosine phosphorylation and complex formation of Cbl-b upon T cell receptor stimulation. Oncogene. 1999 Feb 4;18(5):1147-56. PMID:10022120 doi:10.1038/sj.onc.1202411
- ↑ Ettenberg SA, Keane MM, Nau MM, Frankel M, Wang LM, Pierce JH, Lipkowitz S. cbl-b inhibits epidermal growth factor receptor signaling. Oncogene. 1999 Mar 11;18(10):1855-66. PMID:10086340 doi:10.1038/sj.onc.1202499
- ↑ Fang D, Wang HY, Fang N, Altman Y, Elly C, Liu YC. Cbl-b, a RING-type E3 ubiquitin ligase, targets phosphatidylinositol 3-kinase for ubiquitination in T cells. J Biol Chem. 2001 Feb 16;276(7):4872-8. Epub 2000 Nov 21. PMID:11087752 doi:10.1074/jbc.M008901200
- ↑ Fang D, Liu YC. Proteolysis-independent regulation of PI3K by Cbl-b-mediated ubiquitination in T cells. Nat Immunol. 2001 Sep;2(9):870-5. PMID:11526404 doi:10.1038/ni0901-870
- ↑ Dou H, Buetow L, Sibbet GJ, Cameron K, Huang DT. Essentiality of a non-RING element in priming donor ubiquitin for catalysis by a monomeric E3. Nat Struct Mol Biol. 2013 Jul 14. doi: 10.1038/nsmb.2621. PMID:23851457 doi:10.1038/nsmb.2621
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