1i8l

<StructureSection load='1i8l' size='340' side='right' caption='[[1i8l]], [[Resolution|resolution]] 3.00&Aring;' scene=''>

<table><tr><td colspan='2'>[[1i8l]] is a 4 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=1I8L OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1I8L FirstGlance]. <br>

</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=MAN:ALPHA-D-MANNOSE'>MAN</scene>, <scene name='pdbligand=NAG:N-ACETYL-D-GLUCOSAMINE'>NAG</scene></td></tr>

<tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[1dr9|1dr9]]</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=1i8l FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1i8l OCA], [http://pdbe.org/1i8l PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=1i8l RCSB], [http://www.ebi.ac.uk/pdbsum/1i8l PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=1i8l ProSAT]</span></td></tr>

== Disease ==

[[http://www.uniprot.org/uniprot/CTLA4_HUMAN CTLA4_HUMAN]] Genetic variation in CTLA4 influences susceptibility to systemic lupus erythematosus (SLE) [MIM:[http://omim.org/entry/152700 152700]]. SLE is a chronic, inflammatory and often febrile multisystemic disorder of connective tissue. It affects principally the skin, joints, kidneys and serosal membranes. SLE is thought to represent a failure of the regulatory mechanisms of the autoimmune system.<ref>PMID:10924276</ref> Note=Genetic variations in CTLA4 may influence susceptibility to Graves disease, an autoimmune disorder associated with overactivity of the thyroid gland and hyperthyroidism.<ref>PMID:10924276</ref> Genetic variation in CTLA4 is the cause of susceptibility to diabetes mellitus insulin-dependent type 12 (IDDM12) [MIM:[http://omim.org/entry/601388 601388]]. 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:10924276</ref> <ref>PMID:9259273</ref> Genetic variation in CTLA4 is the cause of susceptibility to celiac disease type 3 (CELIAC3) [MIM:[http://omim.org/entry/609755 609755]]. It is a multifactorial disorder of the small intestine that is influenced by both environmental and genetic factors. It is characterized by malabsorption resulting from inflammatory injury to the mucosa of the small intestine after the ingestion of wheat gluten or related rye and barley proteins. In its classic form, celiac disease is characterized in children by malabsorption and failure to thrive.

[[http://www.uniprot.org/uniprot/CD80_HUMAN CD80_HUMAN]] Involved in the costimulatory signal essential for T-lymphocyte activation. T-cell proliferation and cytokine production is induced by the binding of CD28 or CTLA-4 to this receptor. [[http://www.uniprot.org/uniprot/CTLA4_HUMAN CTLA4_HUMAN]] Inhibitory receptor acting as a major negative regulator of T-cell responses. The affinity of CTLA4 for its natural B7 family ligands, CD80 and CD86, is considerably stronger than the affinity of their cognate stimulatory coreceptor CD28.<ref>PMID:1714933</ref> <ref>PMID:16551244</ref>

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== Publication Abstract from PubMed ==

Optimal immune responses require both an antigen-specific and a co-stimulatory signal. The shared ligands B7-1 and B7-2 on antigen-presenting cells deliver the co-stimulatory signal through CD28 and CTLA-4 on T cells. Signalling through CD28 augments the T-cell response, whereas CTLA-4 signalling attenuates it. Numerous animal studies and recent clinical trials indicate that manipulating these interactions holds considerable promise for immunotherapy. With the consequences of these signals well established, and details of the downstream signalling events emerging, understanding the molecular nature of these extracellular interactions becomes crucial. Here we report the crystal structure of the human CTLA-4/B7-1 co-stimulatory complex at 3.0 A resolution. In contrast to other interacting cell-surface molecules, the relatively small CTLA-4/B7-1 binding interface exhibits an unusually high degree of shape complementarity. CTLA-4 forms homodimers through a newly defined interface of highly conserved residues. In the crystal lattice, CTLA-4 and B7-1 pack in a strikingly periodic arrangement in which bivalent CTLA-4 homodimers bridge bivalent B7-1 homodimers. This zipper-like oligomerization provides the structural basis for forming unusually stable signalling complexes at the T-cell surface, underscoring the importance of potent inhibitory signalling in human immune responses.

 

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== References ==

[[Category: Human]]

[[Category: Mosyak, L]]

[[Category: Somers, W S]]

[[Category: Stamper, C C]]

[[Category: Immune system]]

[[Category: Receptor]]