CD8: Diferenzas entre revisións
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{{proteína |
{{proteína |
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| Name = [[CD8A|molécula CD8a]] |
| Name = [[CD8A|molécula CD8a]] |
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| caption = Estrutura cristalográfica da molécula CD8.<ref name="pmid1547508">[http://www.rcsb.org/pdb/explore/explore.do?structureId=1cd8 PDB - 1cd8]; {{cite journal | author = Leahy DJ, Axel R, Hendrickson WA | title = Crystal structure of a soluble form of the human T cell coreceptor CD8 at 2.6 A resolution | journal = Cell | volume = 68 | issue = 6 | pages = 1145–62 | year = 1992 | month = March | pmid = 1547508 | doi = 10.1016/0092-8674(92)90085-Q | url = }}</ref> |
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| image = CD8Pretty.png |
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Revisión como estaba o 19 de febreiro de 2013 ás 19:24
 | Este artigo está a ser traducido ao galego por un usuario desta Wikipedia; por favor, non o edite. O usuario Miguelferig (conversa · contribucións) realizou a última edición na páxina hai 11 anos. Se o usuario non publica a tradución nun prazo de trinta días, procederase ó seu borrado rápido. |
| Ficheiro:CD8Pretty.png | |
| Estrutura cristalográfica da molécula CD8.[1] | |
CD8
| |
| Identificadores | |
| Símbolo | CD8A |
| Símbolos alt. | CD8 |
| Entrez | 925 |
| HUGO | 1706 |
| OMIM | |
| RefSeq | NM_001768 |
| UniProt | P01732 |
| Outros datos | |
| Locus | Cr. 2 p12 |
CD8b molecule
| |
| Identificadores | |
| Símbolo | CD8B |
| Símbolos alt. | CD8B1 |
| Entrez | 926 |
| HUGO | 1707 |
| OMIM | |
| RefSeq | NM_172099 |
| UniProt | P10966 |
| Outros datos | |
O CD8 (clúster de diferenciación 8) é unha glicoproteína transmembrana que serve como correceptor para o receptor de células T (TCR). Igual que o receptor TCR das células T, o CD8 únese a moléculas do complexo maior de histocompatibilidade (MHC), pero é específico para as de clase I.[2] There are two isoforms of the protein, alpha and beta, each encoded by a different gene. In humans, both genes are located on chromosome 2 in position 2p12.
Distribución nos tecidos
The CD8 co-receptor is predominantly expressed on the surface of cytotoxic T cells, but can also be found on natural killer cells, cortical thymocytes, and dendritic cells. It is expressed in T cell lymphoblastic lymphoma and hypo-pigmented mycosis fungoides, but is frequently lost in other T-cell neoplasms.[3]
Estrutura
To function, CD8 forms a dimer, consisting of a pair of CD8 chains. The most common form of CD8 is composed of a CD8-α and CD8-β chain, both members of the immunoglobulin superfamily with an immunoglobulin variable (IgV)-like extracellular domain connected to the membrane by a thin stalk, and an intracellular tail. Less-common homodimers of the CD8-α chain are also expressed on some cells. The molecular weight of CD8 is about 13,463.2 Da. The structure of the CD8 molecule was determined by Leahy, D.J., Axel, R., and Hendrickson, W.A. by X-ray Diffraction at a 2.6A resolution.[1] The structure was determined to have an immunoglobulin-like beta-sandwich folding and 114 amino acid residues. 2% of the protein is wound into α-helices and 46% into β-sheets, with the remaining 52% of the molecules remaining in the loop portions.
Función
The extracellular IgV-like domain of CD8-α interacts with the α3 portion of the Class I MHC molecule.[4] This affinity keeps the T cell receptor of the cytotoxic T cell and the target cell bound closely together during antigen-specific activation. Cytotoxic T cells with CD8 surface protein are called CD8+ T cells. The main recognition site is a flexible loop at the a3 domain of an MHC molecule. This was discovered by doing mutational analyses. The flexible a3 domain is located between residues 223 and 229 in the genome.[1]
Notas
- ↑ 1,0 1,1 1,2 PDB - 1cd8; Leahy DJ, Axel R, Hendrickson WA (1992). "Crystal structure of a soluble form of the human T cell coreceptor CD8 at 2.6 A resolution". Cell 68 (6): 1145–62. PMID 1547508. doi:10.1016/0092-8674(92)90085-Q. Parámetro descoñecido
|month=ignorado (Axuda) - ↑ Gao G, Jakobsen B (2000). "Molecular interactions of coreceptor CD8 and MHC class I: the molecular basis for functional coordination with the T-cell receptor". Immunol Today 21 (12): 630–6. PMID 11114424. doi:10.1016/S0167-5699(00)01750-3.
- ↑ Leong, Anthony S-Y; Cooper, Kumarason; Leong, F Joel W-M (2003). Manual of Diagnostic Cytology (2 ed.). Greenwich Medical Media, Ltd. p. 73. ISBN 1-84110-100-1.
- ↑ Devine L, Sun J, Barr M, Kavathas P (1999). "Orientation of the Ig domains of CD8 alpha beta relative to MHC class I". J Immunol 162 (2): 846–51. PMID 9916707.
Ligazóns externas
- http://www.tcells.org/scientific/CD8/ T-cell Group - Cardiff University]
- Mapa dos antíxenos CD do rato
- Mapa dos antíxenos CD humanos