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3vgo

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Revision as of 10:25, 25 December 2014

Crystal structure of the N-terminal fragment of Cbl-b

Structural highlights

3vgo is a 3 chain structure with sequence from Homo sapiens. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Gene:	CBLB (Homo sapiens)
Resources:	FirstGlance, OCA, RCSB, PDBsum

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

Cbl-b is a RING-type E3 ubiquitin ligase that functions as a negative regulator of T-cell activation and growth factor receptor and nonreceptor-type tyrosine kinase signaling. Cbl-b dysfunction is related to autoimmune diseases and cancers in humans. However, the molecular mechanism regulating its E3 activity is largely unknown. NMR and small-angle X-ray scattering analyses revealed that the unphosphorylated N-terminal region of Cbl-b forms a compact structure by an intramolecular interaction, which masks the interaction surface of the RING domain with an E2 ubiquitin-conjugating enzyme. Phosphorylation of Y363, located in the helix-linker region between the tyrosine kinase binding and the RING domains, disrupts the interdomain interaction to expose the E2 binding surface of the RING domain. Structural analysis revealed that the phosphorylated helix-RING region forms a compact structure in solution. Moreover, the phosphate group of pY363 is located in the vicinity of the interaction surface with UbcH5B to increase affinity by reducing their electrostatic repulsion. Thus, the phosphorylation of Y363 regulates the E3 activity of Cbl-b by two mechanisms: one is to remove the masking of the RING domain from the tyrosine kinase binding domain and the other is to form a surface to enhance binding affinity to E2.

Autoinhibition and phosphorylation-induced activation mechanisms of human cancer and autoimmune disease-related E3 protein Cbl-b.,Kobashigawa Y, Tomitaka A, Kumeta H, Noda NN, Yamaguchi M, Inagaki F Proc Natl Acad Sci U S A. 2011 Dec 20;108(51):20579-84. Epub 2011 Dec 7. PMID:22158902^[5]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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
↑ Kobashigawa Y, Tomitaka A, Kumeta H, Noda NN, Yamaguchi M, Inagaki F. Autoinhibition and phosphorylation-induced activation mechanisms of human cancer and autoimmune disease-related E3 protein Cbl-b. Proc Natl Acad Sci U S A. 2011 Dec 20;108(51):20579-84. Epub 2011 Dec 7. PMID:22158902 doi:10.1073/pnas.1110712108

1 Structural highlights
2 Function
3 Publication Abstract from PubMed
4 See Also
5 References

Proteopedia Page Contributors and Editors (what is this?)

OCA

Retrieved from "http://52.214.119.220/wiki/index.php/3vgo"

@@ Line 6: / Line 6: @@
 <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=3vgo FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3vgo OCA], [http://www.rcsb.org/pdb/explore.do?structureId=3vgo RCSB], [http://www.ebi.ac.uk/pdbsum/3vgo PDBsum]</span></td></tr>
 </table>
+== Function ==
+[[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>
 <div style="background-color:#fffaf0;">
 == Publication Abstract from PubMed ==

3vgo

From Proteopedia

Revision as of 10:25, 25 December 2014

Crystal structure of the N-terminal fragment of Cbl-b

Structural highlights

Function

Publication Abstract from PubMed

See Also

References

Contents

Proteopedia Page Contributors and Editors (what is this?)

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