View source for 4z76


==Weak TCR binding to an unstable insulin epitope drives type 1 diabetes==
<StructureSection load='4z76' size='340' side='right' caption='[[4z76]], [[Resolution|resolution]] 1.88&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[4z76]] is a 6 chain structure. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4Z76 OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=4Z76 FirstGlance]. <br>
</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=EDO:1,2-ETHANEDIOL'>EDO</scene>, <scene name='pdbligand=GOL:GLYCEROL'>GOL</scene>, <scene name='pdbligand=SO4:SULFATE+ION'>SO4</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=4z76 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4z76 OCA], [http://pdbe.org/4z76 PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=4z76 RCSB], [http://www.ebi.ac.uk/pdbsum/4z76 PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=4z76 ProSAT]</span></td></tr>
</table>
== Disease ==
[[http://www.uniprot.org/uniprot/INS_HUMAN INS_HUMAN]] Defects in INS are the cause of familial hyperproinsulinemia (FHPRI) [MIM:[http://omim.org/entry/176730 176730]].<ref>PMID:3470784</ref> <ref>PMID:2196279</ref> <ref>PMID:4019786</ref> <ref>PMID:1601997</ref>   Defects in INS are a cause of diabetes mellitus insulin-dependent type 2 (IDDM2) [MIM:[http://omim.org/entry/125852 125852]]. IDDM2 is a multifactorial disorder of glucose homeostasis that is characterized by susceptibility to ketoacidosis in the absence of insulin therapy. Clinical fetaures are polydipsia, polyphagia and polyuria which result from hyperglycemia-induced osmotic diuresis and secondary thirst. These derangements result in long-term complications that affect the eyes, kidneys, nerves, and blood vessels.<ref>PMID:18192540</ref>   Defects in INS are a cause of diabetes mellitus permanent neonatal (PNDM) [MIM:[http://omim.org/entry/606176 606176]]. PNDM is a rare form of diabetes distinct from childhood-onset autoimmune diabetes mellitus type 1. It is characterized by insulin-requiring hyperglycemia that is diagnosed within the first months of life. Permanent neonatal diabetes requires lifelong therapy.<ref>PMID:17855560</ref> <ref>PMID:18162506</ref>   Defects in INS are a cause of maturity-onset diabetes of the young type 10 (MODY10) [MIM:[http://omim.org/entry/613370 613370]]. MODY10 is a form of diabetes that is characterized by an autosomal dominant mode of inheritance, onset in childhood or early adulthood (usually before 25 years of age), a primary defect in insulin secretion and frequent insulin-independence at the beginning of the disease.<ref>PMID:18192540</ref> <ref>PMID:18162506</ref> <ref>PMID:20226046</ref>  [[http://www.uniprot.org/uniprot/B2MG_HUMAN B2MG_HUMAN]] Defects in B2M are the cause of hypercatabolic hypoproteinemia (HYCATHYP) [MIM:[http://omim.org/entry/241600 241600]]. Affected individuals show marked reduction in serum concentrations of immunoglobulin and albumin, probably due to rapid degradation.<ref>PMID:16549777</ref>   Note=Beta-2-microglobulin may adopt the fibrillar configuration of amyloid in certain pathologic states. The capacity to assemble into amyloid fibrils is concentration dependent. Persistently high beta(2)-microglobulin serum levels lead to amyloidosis in patients on long-term hemodialysis.<ref>PMID:3532124</ref> <ref>PMID:1336137</ref> <ref>PMID:7554280</ref> <ref>PMID:4586824</ref> <ref>PMID:8084451</ref> <ref>PMID:12119416</ref> <ref>PMID:12796775</ref> <ref>PMID:16901902</ref> <ref>PMID:16491088</ref> <ref>PMID:17646174</ref> <ref>PMID:18835253</ref> <ref>PMID:18395224</ref> <ref>PMID:19284997</ref>  
== Function ==
[[http://www.uniprot.org/uniprot/HA1D_MOUSE HA1D_MOUSE]] Involved in the presentation of foreign antigens to the immune system. [[http://www.uniprot.org/uniprot/INS_HUMAN INS_HUMAN]] Insulin decreases blood glucose concentration. It increases cell permeability to monosaccharides, amino acids and fatty acids. It accelerates glycolysis, the pentose phosphate cycle, and glycogen synthesis in liver. [[http://www.uniprot.org/uniprot/B2MG_HUMAN B2MG_HUMAN]] Component of the class I major histocompatibility complex (MHC). Involved in the presentation of peptide antigens to the immune system. 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
The NOD mouse model of type 1 diabetes (T1D) continues to be an important tool for delineating the role of T-cell-mediated destruction of pancreatic beta-cells. However, little is known about the molecular mechanisms that enable this disease pathway. We show that insulin reactivity by a CD8+ T-cell clone known to induce T1D is characterised by weak T cell antigen receptor (TCR) binding to a relatively unstable peptide-major histocompatibility complex (pMHC). The structure of the native 9-mer and 10-mer insulin epitopes demonstrated that peptide residues 7 and 8 form a prominent solvent exposed bulge that could potentially be the main focus of TCR binding. The C-terminus of the peptide governed pMHC stability. Unexpectedly, we further demonstrate a novel mode of flexible peptide presentation in which the MHC peptide-binding groove is able to 'open the back door' to accommodate extra C-terminal peptide residues.

Distortion of the MHC class I binding groove to accommodate an insulin-derived 10-mer peptide.,Motozono C, Pearson JA, De Leenheer E, Rizkallah PJ, Beck K, Trimby A, Sewell AK, Wong FS, Cole DK J Biol Chem. 2015 Jun 17. pii: jbc.M114.622522. PMID:26085090<ref>PMID:26085090</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 4z76" style="background-color:#fffaf0;"></div>

==See Also==
*[[Beta-2 microglobulin|Beta-2 microglobulin]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Cole, D K]]
[[Category: Rizkallah, P J]]
[[Category: H-2kd]]
[[Category: Immune system]]
[[Category: Immunoglobulin]]
[[Category: Type 1 diabetes]]