4c56: Difference between revisions

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<StructureSection load='4c56' size='340' side='right'caption='[[4c56]], [[Resolution|resolution]] 2.90&Aring;' scene=''>
<StructureSection load='4c56' size='340' side='right'caption='[[4c56]], [[Resolution|resolution]] 2.90&Aring;' scene=''>
== Structural highlights ==
== Structural highlights ==
<table><tr><td colspan='2'>[[4c56]] is a 12 chain structure with sequence from [http://en.wikipedia.org/wiki/"micrococcus_aureus"_(rosenbach_1884)_zopf_1885 "micrococcus aureus" (rosenbach 1884) zopf 1885] and [http://en.wikipedia.org/wiki/Human Human]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4C56 OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=4C56 FirstGlance]. <br>
<table><tr><td colspan='2'>[[4c56]] is a 12 chain structure with sequence from [https://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens], [https://en.wikipedia.org/wiki/Influenza_A_virus Influenza A virus] and [https://en.wikipedia.org/wiki/Staphylococcus_aureus Staphylococcus aureus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4C56 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=4C56 FirstGlance]. <br>
</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=GOL:GLYCEROL'>GOL</scene></td></tr>
</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=GOL:GLYCEROL'>GOL</scene></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=4c56 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4c56 OCA], [http://pdbe.org/4c56 PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=4c56 RCSB], [http://www.ebi.ac.uk/pdbsum/4c56 PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=4c56 ProSAT]</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=4c56 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4c56 OCA], [https://pdbe.org/4c56 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=4c56 RCSB], [https://www.ebi.ac.uk/pdbsum/4c56 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=4c56 ProSAT]</span></td></tr>
</table>
</table>
== Disease ==
[[https://www.uniprot.org/uniprot/TRAC_HUMAN TRAC_HUMAN]] TCR-alpha-beta-positive T-cell deficiency. The disease is caused by variants affecting the gene represented in this entry.
== Function ==
== Function ==
[[http://www.uniprot.org/uniprot/HEMA_I89A7 HEMA_I89A7]] Binds to sialic acid-containing receptors on the cell surface, bringing about the attachment of the virus particle to the cell. This attachment induces virion internalization of about two third of the virus particles through clathrin-dependent endocytosis and about one third through a clathrin- and caveolin-independent pathway. Plays a major role in the determination of host range restriction and virulence. Class I viral fusion protein. Responsible for penetration of the virus into the cell cytoplasm by mediating the fusion of the membrane of the endocytosed virus particle with the endosomal membrane. Low pH in endosomes induces an irreversible conformational change in HA2, releasing the fusion hydrophobic peptide. Several trimers are required to form a competent fusion pore (By similarity). [[http://www.uniprot.org/uniprot/DRA_HUMAN DRA_HUMAN]] Binds peptides derived from antigens that access the endocytic route of antigen presenting cells (APC) and presents them on the cell surface for recognition by the CD4 T-cells. The peptide binding cleft accommodates peptides of 10-30 residues. The peptides presented by MHC class II molecules are generated mostly by degradation of proteins that access the endocytic route, where they are processed by lysosomal proteases and other hydrolases. Exogenous antigens that have been endocytosed by the APC are thus readily available for presentation via MHC II molecules, and for this reason this antigen presentation pathway is usually referred to as exogenous. As membrane proteins on their way to degradation in lysosomes as part of their normal turn-over are also contained in the endosomal/lysosomal compartments, exogenous antigens must compete with those derived from endogenous components. Autophagy is also a source of endogenous peptides, autophagosomes constitutively fuse with MHC class II loading compartments. In addition to APCs, other cells of the gastrointestinal tract, such as epithelial cells, express MHC class II molecules and CD74 and act as APCs, which is an unusual trait of the GI tract. To produce a MHC class II molecule that presents an antigen, three MHC class II molecules (heterodimers of an alpha and a beta chain) associate with a CD74 trimer in the ER to form a heterononamer. Soon after the entry of this complex into the endosomal/lysosomal system where antigen processing occurs, CD74 undergoes a sequential degradation by various proteases, including CTSS and CTSL, leaving a small fragment termed CLIP (class-II-associated invariant chain peptide). The removal of CLIP is facilitated by HLA-DM via direct binding to the alpha-beta-CLIP complex so that CLIP is released. HLA-DM stabilizes MHC class II molecules until primary high affinity antigenic peptides are bound. The MHC II molecule bound to a peptide is then transported to the cell membrane surface. In B-cells, the interaction between HLA-DM and MHC class II molecules is regulated by HLA-DO. Primary dendritic cells (DCs) also to express HLA-DO. Lysosomal miroenvironment has been implicated in the regulation of antigen loading into MHC II molecules, increased acidification produces increased proteolysis and efficient peptide loading.
[[https://www.uniprot.org/uniprot/TRAC_HUMAN TRAC_HUMAN]] Constant region of T cell receptor (TR) alpha chain (PubMed:24600447). Alpha-beta T cell receptors are antigen specific receptors which are essential to the immune response and are present on the cell surface of T lymphocytes. Recognize peptide-major histocompatibility (MH) (pMH) complexes that are displayed by antigen presenting cells (APC), a prerequisite for efficient T cell adaptive immunity against pathogens (PubMed:25493333). Binding of alpha-beta TR to pMH complex initiates TR-CD3 clustering on the cell surface and intracellular activation of LCK that phosphorylates the ITAM motifs of CD3G, CD3D, CD3E and CD247 enabling the recruitment of ZAP70. In turn, ZAP70 phosphorylates LAT, which recruits numerous signaling molecules to form the LAT signalosome. The LAT signalosome propagates signal branching to three major signaling pathways, the calcium, the mitogen-activated protein kinase (MAPK) kinase and the nuclear factor NF-kappa-B (NF-kB) pathways, leading to the mobilization of transcription factors that are critical for gene expression and essential for T cell growth and differentiation (PubMed:23524462). The T cell repertoire is generated in the thymus, by V-(D)-J rearrangement. This repertoire is then shaped by intrathymic selection events to generate a peripheral T cell pool of self-MH restricted, non-autoaggressive T cells. Post-thymic interaction of alpha-beta TR with the pMH complexes shapes TR structural and functional avidity (PubMed:15040585).<ref>PMID:15040585</ref> <ref>PMID:23524462</ref> <ref>PMID:24600447</ref> <ref>PMID:25493333</ref>  
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Superantigens are immune-stimulatory toxins produced by Staphylococcus aureus, which are able to interact with host immune receptors to induce a massive release of cytokines, causing toxic shock syndrome and possibly death. In this article, we present the x-ray structure of staphylococcal enterotoxin B (SEB) in complex with its receptors, the TCR and MHC class II, forming a ternary complex. The structure, in combination with functional analyses, clearly shows how SEB adopts a wedge-like position when binding to the beta-chain of TCR, allowing for an interaction between the alpha-chain of TCR and MHC. Furthermore, the binding mode also circumvents contact between TCR and the peptide presented by MHC, which enables SEB to initiate a peptide-independent activation of T cells.
 
Structure of the Superantigen Staphylococcal Enterotoxin B in Complex with TCR and Peptide-MHC Demonstrates Absence of TCR-Peptide Contacts.,Rodstrom KE, Elbing K, Lindkvist-Petersson K J Immunol. 2014 Jul 11. pii: 1401268. PMID:25015819<ref>PMID:25015819</ref>
 
From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 4c56" style="background-color:#fffaf0;"></div>


==See Also==
==See Also==
*[[Major histocompatibility complex|Major histocompatibility complex]]
*[[MHC 3D structures|MHC 3D structures]]
*[[T-cell receptor|T-cell receptor]]
*[[T-cell receptor 3D structures|T-cell receptor 3D structures]]
== References ==
== References ==
<references/>
<references/>
__TOC__
__TOC__
</StructureSection>
</StructureSection>
[[Category: Human]]
[[Category: Homo sapiens]]
[[Category: Influenza A virus]]
[[Category: Large Structures]]
[[Category: Large Structures]]
[[Category: Elbing, K]]
[[Category: Staphylococcus aureus]]
[[Category: Lindkvist-Petersson, K]]
[[Category: Elbing K]]
[[Category: Rodstrom, K E.J]]
[[Category: Lindkvist-Petersson K]]
[[Category: Immune system-toxin complex]]
[[Category: Rodstrom KEJ]]

Revision as of 20:27, 7 September 2022

X-ray structure of the complex between staphylococcal enterotoxin B, T cell receptor and major histocompatibility complex class IIX-ray structure of the complex between staphylococcal enterotoxin B, T cell receptor and major histocompatibility complex class II

Structural highlights

4c56 is a 12 chain structure with sequence from Homo sapiens, Influenza A virus and Staphylococcus aureus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Ligands:
Resources:FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Disease

[TRAC_HUMAN] TCR-alpha-beta-positive T-cell deficiency. The disease is caused by variants affecting the gene represented in this entry.

Function

[TRAC_HUMAN] Constant region of T cell receptor (TR) alpha chain (PubMed:24600447). Alpha-beta T cell receptors are antigen specific receptors which are essential to the immune response and are present on the cell surface of T lymphocytes. Recognize peptide-major histocompatibility (MH) (pMH) complexes that are displayed by antigen presenting cells (APC), a prerequisite for efficient T cell adaptive immunity against pathogens (PubMed:25493333). Binding of alpha-beta TR to pMH complex initiates TR-CD3 clustering on the cell surface and intracellular activation of LCK that phosphorylates the ITAM motifs of CD3G, CD3D, CD3E and CD247 enabling the recruitment of ZAP70. In turn, ZAP70 phosphorylates LAT, which recruits numerous signaling molecules to form the LAT signalosome. The LAT signalosome propagates signal branching to three major signaling pathways, the calcium, the mitogen-activated protein kinase (MAPK) kinase and the nuclear factor NF-kappa-B (NF-kB) pathways, leading to the mobilization of transcription factors that are critical for gene expression and essential for T cell growth and differentiation (PubMed:23524462). The T cell repertoire is generated in the thymus, by V-(D)-J rearrangement. This repertoire is then shaped by intrathymic selection events to generate a peripheral T cell pool of self-MH restricted, non-autoaggressive T cells. Post-thymic interaction of alpha-beta TR with the pMH complexes shapes TR structural and functional avidity (PubMed:15040585).[1] [2] [3] [4]

See Also

References

  1. ↑ Nikolich-Zugich J, Slifka MK, Messaoudi I. The many important facets of T-cell repertoire diversity. Nat Rev Immunol. 2004 Feb;4(2):123-32. doi: 10.1038/nri1292. PMID:15040585 doi:http://dx.doi.org/10.1038/nri1292
  2. ↑ Brownlie RJ, Zamoyska R. T cell receptor signalling networks: branched, diversified and bounded. Nat Rev Immunol. 2013 Apr;13(4):257-69. doi: 10.1038/nri3403. PMID:23524462 doi:http://dx.doi.org/10.1038/nri3403
  3. ↑ Lefranc MP. Immunoglobulin and T Cell Receptor Genes: IMGT((R)) and the Birth and Rise of Immunoinformatics. Front Immunol. 2014 Feb 5;5:22. doi: 10.3389/fimmu.2014.00022. eCollection 2014. PMID:24600447 doi:http://dx.doi.org/10.3389/fimmu.2014.00022
  4. ↑ Rossjohn J, Gras S, Miles JJ, Turner SJ, Godfrey DI, McCluskey J. T cell antigen receptor recognition of antigen-presenting molecules. Annu Rev Immunol. 2015;33:169-200. doi: 10.1146/annurev-immunol-032414-112334., Epub 2014 Dec 10. PMID:25493333 doi:http://dx.doi.org/10.1146/annurev-immunol-032414-112334

4c56, resolution 2.90Å

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