1i8l

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1i8l, resolution 3.00Å ()
Ligands: ,
Related: 1dr9
Resources: FirstGlance, OCA, RCSB, PDBsum
Coordinates: save as pdb, mmCIF, xml


Contents

HUMAN B7-1/CTLA-4 CO-STIMULATORY COMPLEX

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.

Crystal structure of the B7-1/CTLA-4 complex that inhibits human immune responses., Stamper CC, Zhang Y, Tobin JF, Erbe DV, Ikemizu S, Davis SJ, Stahl ML, Seehra J, Somers WS, Mosyak L, Nature. 2001 Mar 29;410(6828):608-11. PMID:11279502

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

Disease

[CTLA4_HUMAN] Genetic variation in CTLA4 influences susceptibility to systemic lupus erythematosus (SLE) [MIM: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.[1] Note=Genetic variations in CTLA4 may influence susceptibility to Graves disease, an autoimmune disorder associated with overactivity of the thyroid gland and hyperthyroidism.[2] Genetic variation in CTLA4 is the cause of susceptibility to diabetes mellitus insulin-dependent type 12 (IDDM12) [MIM: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.[3][4] Genetic variation in CTLA4 is the cause of susceptibility to celiac disease type 3 (CELIAC3) [MIM: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.

Function

[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. [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.[5][6]

About this Structure

1i8l is a 4 chain structure with sequence from Homo sapiens. Full crystallographic information is available from OCA.

Reference

  • Stamper CC, Zhang Y, Tobin JF, Erbe DV, Ikemizu S, Davis SJ, Stahl ML, Seehra J, Somers WS, Mosyak L. Crystal structure of the B7-1/CTLA-4 complex that inhibits human immune responses. Nature. 2001 Mar 29;410(6828):608-11. PMID:11279502 doi:10.1038/35069118
  1. Chistyakov DA, Savost'anov KV, Turakulov RI, Petunina NA, Trukhina LV, Kudinova AV, Balabolkin MI, Nosikov VV. Complex association analysis of graves disease using a set of polymorphic markers. Mol Genet Metab. 2000 Jul;70(3):214-8. PMID:10924276 doi:10.1006/mgme.2000.3007
  2. Chistyakov DA, Savost'anov KV, Turakulov RI, Petunina NA, Trukhina LV, Kudinova AV, Balabolkin MI, Nosikov VV. Complex association analysis of graves disease using a set of polymorphic markers. Mol Genet Metab. 2000 Jul;70(3):214-8. PMID:10924276 doi:10.1006/mgme.2000.3007
  3. Chistyakov DA, Savost'anov KV, Turakulov RI, Petunina NA, Trukhina LV, Kudinova AV, Balabolkin MI, Nosikov VV. Complex association analysis of graves disease using a set of polymorphic markers. Mol Genet Metab. 2000 Jul;70(3):214-8. PMID:10924276 doi:10.1006/mgme.2000.3007
  4. Marron MP, Raffel LJ, Garchon HJ, Jacob CO, Serrano-Rios M, Martinez Larrad MT, Teng WP, Park Y, Zhang ZX, Goldstein DR, Tao YW, Beaurain G, Bach JF, Huang HS, Luo DF, Zeidler A, Rotter JI, Yang MC, Modilevsky T, Maclaren NK, She JX. Insulin-dependent diabetes mellitus (IDDM) is associated with CTLA4 polymorphisms in multiple ethnic groups. Hum Mol Genet. 1997 Aug;6(8):1275-82. PMID:9259273
  5. Linsley PS, Brady W, Urnes M, Grosmaire LS, Damle NK, Ledbetter JA. CTLA-4 is a second receptor for the B cell activation antigen B7. J Exp Med. 1991 Sep 1;174(3):561-9. PMID:1714933
  6. Teft WA, Kirchhof MG, Madrenas J. A molecular perspective of CTLA-4 function. Annu Rev Immunol. 2006;24:65-97. PMID:16551244 doi:10.1146/annurev.immunol.24.021605.090535

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