<p>An evidence describes the source of an annotation, e.g. an experiment that has been published in the scientific literature, an orthologous protein, a record from another database, etc.</p>
<p><a href="/manual/evidences">More...</a></p>
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<p>The annotation score provides a heuristic measure of the annotation content of a UniProtKB entry or proteome. This score <strong>cannot</strong> be used as a measure of the accuracy of the annotation as we cannot define the ‘correct annotation’ for any given protein.<p><a href='/help/annotation_score' target='_top'>More...</a></p>-Experimental evidence at protein leveli
<p>This indicates the type of evidence that supports the existence of the protein. Note that the ‘protein existence’ evidence does not give information on the accuracy or correctness of the sequence(s) displayed.<p><a href='/help/protein_existence' target='_top'>More...</a></p>
Select a section on the left to see content.
<p>This section provides any useful information about the protein, mostly biological knowledge.<p><a href='/help/function_section' target='_top'>More...</a></p>Functioni
Integral membrane glycoprotein that plays an essential role in the immune response and serves multiple functions in responses against both external and internal offenses. In T-cells, functions primarily as a coreceptor for MHC class I molecule:peptide complex. The antigens presented by class I peptides are derived from cytosolic proteins while class II derived from extracellular proteins. Interacts simultaneously with the T-cell receptor (TCR) and the MHC class I proteins presented by antigen presenting cells (APCs). In turn, recruits the Src kinase LCK to the vicinity of the TCR-CD3 complex. LCK then initiates different intracellular signaling pathways by phosphorylating various substrates ultimately leading to lymphokine production, motility, adhesion and activation of cytotoxic T-lymphocytes (CTLs). This mechanism enables CTLs to recognize and eliminate infected cells and tumor cells. In NK-cells, the presence of CD8A homodimers at the cell surface provides a survival mechanism allowing conjugation and lysis of multiple target cells. CD8A homodimer molecules also promote the survival and differentiation of activated lymphocytes into memory CD8 T-cells.By similarity
<p>Manually curated information which has been propagated from a related experimentally characterized protein.</p>
<p><a href="/manual/evidences#ECO:0000250">More...</a></p>
Manual assertion inferred from sequence similarity toi
<p>Manually curated information for which there is published experimental evidence.</p>
<p><a href="/manual/evidences#ECO:0000269">More...</a></p>
Manual assertion based on experiment ini
<p>The <a href="http://www.geneontology.org/">Gene Ontology (GO)</a> project provides a set of hierarchical controlled vocabulary split into 3 categories:<p><a href='/help/gene_ontology' target='_top'>More...</a></p>GO - Molecular functioni
protein homodimerization activity Source: MGI
<p>Inferred from Direct Assay</p>
<p>Used to indicate a direct assay for the function, process or component indicated by the GO term.</p>
<p>More information in the <a href="http://geneontology.org/page/guide-go-evidence-codes#ida">GO evidence code guide</a></p>
Inferred from direct assayi
cytotoxic T cell differentiation Source: MGI
<p>Inferred from Mutant Phenotype</p>
<p>Describes annotations that are concluded from looking at variations or changes in a gene product such as mutations or abnormal levels and includes techniques such as knockouts, overexpression, anti-sense experiments and use of specific protein inhibitors.</p>
<p>More information in the <a href="http://geneontology.org/page/guide-go-evidence-codes#imp">GO evidence code guide</a></p>
Inferred from mutant phenotypei
<p>UniProtKB Keywords constitute a <a href="http://www.uniprot.org/keywords">controlled vocabulary</a> with a hierarchical structure. Keywords summarise the content of a UniProtKB entry and facilitate the search for proteins of interest.<p><a href='/help/keywords' target='_top'>More...</a></p>Keywordsi
R-MMU-198933 Immunoregulatory interactions between a Lymphoid and a non-Lymphoid cell
<p>This section provides information about the protein and gene name(s) and synonym(s) and about the organism that is the source of the protein sequence.<p><a href='/help/names_and_taxonomy_section' target='_top'>More...</a></p>Names & Taxonomyi
<p>This subsection of the <a href="http://www.uniprot.org/help/names_and_taxonomy_section">Names and taxonomy</a> section provides an exhaustive list of all names of the protein, from commonly used to obsolete, to allow unambiguous identification of a protein.<p><a href='/help/protein_names' target='_top'>More...</a></p>Protein namesi
Recommended name:
T-cell surface glycoprotein CD8 alpha chain
Alternative name(s):
T-cell surface glycoprotein Lyt-2
CD_antigen: CD8a
<p>This subsection of the <a href="http://www.uniprot.org/help/names_and_taxonomy_section">Names and taxonomy</a> section indicates the name(s) of the gene(s) that code for the protein sequence(s) described in the entry. Four distinct tokens exist: ‘Name’, ‘Synonyms’, ‘Ordered locus names’ and ‘ORF names’.<p><a href='/help/gene_name' target='_top'>More...</a></p>Gene namesi
<p>This subsection of the <a href="http://www.uniprot.org/help/names_and_taxonomy_section">Names and taxonomy</a> section provides information on the name(s) of the organism that is the source of the protein sequence.<p><a href='/help/organism-name' target='_top'>More...</a></p>Organismi
<p>This subsection of the <a href="http://www.uniprot.org/help/names_and_taxonomy_section">Names and taxonomy</a> section shows the unique identifier assigned by the NCBI to the source organism of the protein. This is known as the ‘taxonomic identifier’ or ‘taxid’.<p><a href='/help/taxonomic_identifier' target='_top'>More...</a></p>Taxonomic identifieri
<p>This subsection of the <a href="http://www.uniprot.org/help/names_and_taxonomy_section">Names and taxonomy</a> section contains the taxonomic hierarchical classification lineage of the source organism. It lists the nodes as they appear top-down in the taxonomic tree, with the more general grouping listed first.<p><a href='/help/taxonomic_lineage' target='_top'>More...</a></p>Taxonomic lineagei
<p>This subsection of the <a href="http://www.uniprot.org/help/names_and_taxonomy_section">Names and taxonomy</a> section is present for entries that are part of a <a href="http://www.uniprot.org/proteomes">proteome</a>, i.e. of a set of proteins thought to be expressed by organisms whose genomes have been completely sequenced.<p><a href='/help/proteomes_manual' target='_top'>More...</a></p>Proteomesi
UP000000589
<p>A UniProt <a href="http://www.uniprot.org/manual/proteomes_manual">proteome</a> can consist of several components. <br></br>The component name refers to the genomic component encoding a set of proteins.<p><a href='/help/proteome_component' target='_top'>More...</a></p> Componenti: Chromosome 6
Organism-specific databases
Mouse genome database (MGD) from Mouse Genome Informatics (MGI)
<p>This section provides information on the location and the topology of the mature protein in the cell.<p><a href='/help/subcellular_location_section' target='_top'>More...</a></p>Subcellular locationi
<p>This subsection of the <a href="http://www.uniprot.org/help/subcellular_location_section">'Subcellular location'</a> section describes the subcellular compartment where each non-membrane region of a membrane-spanning protein is found.<p><a href='/help/topo_dom' target='_top'>More...</a></p>Topological domaini
<p>This subsection of the <a href="http://www.uniprot.org/help/subcellular_location_section">'Subcellular location'</a> section describes the extent of a membrane-spanning region of the protein. It denotes the presence of both alpha-helical transmembrane regions and the membrane spanning regions of beta-barrel transmembrane proteins.<p><a href='/help/transmem' target='_top'>More...</a></p>Transmembranei
<p>This section provides information on the disease(s) and phenotype(s) associated with a protein.<p><a href='/help/pathology_and_biotech_section' target='_top'>More...</a></p>Pathology & Biotechi
<p>This subsection of the ‘Pathology and Biotech’ section describes the in vivo effects caused by ablation of the gene (or one or more transcripts) coding for the protein described in the entry. This includes gene knockout and knockdown, provided experiments have been performed in the context of a whole organism or a specific tissue, and not at the single-cell level.<p><a href='/help/disruption_phenotype' target='_top'>More...</a></p>Disruption phenotypei
Cd8a-deficient mice prevent the development of class I MHC restricted cytotoxic T-cells. However, maturation of class II MHC restricted T-helper cells seems to be unaffected by the absence of Cd8a.1 Publication
<p>This subsection of the ‘PTM / Processing’ section denotes the presence of an N-terminal signal peptide.<p><a href='/help/signal' target='_top'>More...</a></p>Signal peptidei
<p>This subsection of the ‘PTM / Processing’ section describes the extent of a polypeptide chain in the mature protein following processing.<p><a href='/help/chain' target='_top'>More...</a></p>ChainiPRO_0000014639
<p>This subsection of the PTM / Processing":/help/ptm_processing_section section describes the positions of cysteine residues participating in disulfide bonds.<p><a href='/help/disulfid' target='_top'>More...</a></p>Disulfide bondi
<p>Manual validated information which has been generated by the UniProtKB automatic annotation system.</p>
<p><a href="/manual/evidences#ECO:0000255">More...</a></p>
Manual assertion according to rulesi
Cited for: X-RAY CRYSTALLOGRAPHY (2.7 ANGSTROMS) OF 28-151 IN COMPLEX WITH CD8B AND ANTIBODY, SUBUNIT, DISULFIDE BOND, GLYCOSYLATION AT ASN-69.
<p>This subsection of the <a href="http://www.uniprot.org/help/ptm_processing_section">PTM / Processing</a> section specifies the position and type of each covalently attached glycan group (mono-, di-, or polysaccharide).<p><a href='/help/carbohyd' target='_top'>More...</a></p>Glycosylationi
<p>This subsection of the <a href="http://www.uniprot.org/help/ptm_processing_section">PTM/processing</a> section describes post-translational modifications (PTMs). This subsection <strong>complements</strong> the information provided at the sequence level or describes modifications for which <strong>position-specific data is not yet available</strong>.<p><a href='/help/post-translational_modification' target='_top'>More...</a></p>Post-translational modificationi
Palmitoylated, but association with CD8B seems to be more important for the enrichment of CdD8A in lipid rafts.By similarity
Manual assertion inferred from sequence similarity toi
<p>This section provides information on the expression of a gene at the mRNA or protein level in cells or in tissues of multicellular organisms.<p><a href='/help/expression_section' target='_top'>More...</a></p>Expressioni
<p>This section provides information on the quaternary structure of a protein and on interaction(s) with other proteins or protein complexes.<p><a href='/help/interaction_section' target='_top'>More...</a></p>Interactioni
<p>This subsection of the <a href="http://www.uniprot.org/help/interaction_section">'Interaction'</a> section provides information about the protein quaternary structure and interaction(s) with other proteins or protein complexes (with the exception of physiological receptor-ligand interactions which are annotated in the <a href="http://www.uniprot.org/help/function_section">'Function'</a> section).<p><a href='/help/subunit_structure' target='_top'>More...</a></p>Subunit structurei
Forms disulfide-linked heterodimers with CD8B at the cell surface. Forms also homodimers in several cell types including NK-cells or peripheral blood T-lymphocytes. Interacts with the MHC class I HLA-A/B2M dimer. Interacts with LCK in a zinc-dependent manner.By similarity
Manual assertion inferred from sequence similarity toi
Cited for: X-RAY CRYSTALLOGRAPHY (2.7 ANGSTROMS) OF 28-151 IN COMPLEX WITH CD8B AND ANTIBODY, SUBUNIT, DISULFIDE BOND, GLYCOSYLATION AT ASN-69.
<p>This subsection of the '<a href="http://www.uniprot.org/help/interaction_section%27">Interaction</a> section provides information about binary protein-protein interactions. The data presented in this section are a quality-filtered subset of binary interactions automatically derived from the <a href="http://www.ebi.ac.uk/intact/">IntAct database</a>. It is updated on a monthly basis. Each binary interaction is displayed on a separate line.<p><a href='/help/binary_interactions' target='_top'>More...</a></p>Binary interactionsi
<p>This section provides information on the tertiary and secondary structure of a protein.<p><a href='/help/structure_section' target='_top'>More...</a></p>Structurei
Secondary structure
Legend: HelixTurnBeta strandPDB Structure known for this area
<p>This subsection of the ‘Structure’ section is used to indicate the positions of experimentally determined beta strands within the protein sequence.<p><a href='/help/strand' target='_top'>More...</a></p>Beta strandi
<p>Manually validated information inferred from a combination of experimental and computational evidence.</p>
<p><a href="/manual/evidences#ECO:0000244">More...</a></p>
Manual assertion inferred from combination of experimental and computational evidencei
<p>This subsection of the ‘Structure’ section is used to indicate the positions of experimentally determined hydrogen-bonded turns within the protein sequence. These elements correspond to the DSSP secondary structure code ‘T’.<p><a href='/help/turn' target='_top'>More...</a></p>Turni
<p>This subsection of the ‘Structure’ section is used to indicate the positions of experimentally determined helical regions within the protein sequence.<p><a href='/help/helix' target='_top'>More...</a></p>Helixi
<p>This section provides information on sequence similarities with other proteins and the domain(s) present in a protein.<p><a href='/help/family_and_domains_section' target='_top'>More...</a></p>Family & Domainsi
Domains and Repeats
Feature key
Position(s)
DescriptionActions
Graphical view
Length
<p>This subsection of the <a href="http://www.uniprot.org/help/family_and_domains_section">Family and Domains</a> section describes the position and type of a domain, which is defined as a specific combination of secondary structures organized into a characteristic three-dimensional structure or fold.<p><a href='/help/domain' target='_top'>More...</a></p>Domaini
<p>This section displays by default the canonical protein sequence and upon request all isoforms described in the entry. It also includes information pertinent to the sequence(s), including <a href="http://www.uniprot.org/help/sequence_length">length</a> and <a href="http://www.uniprot.org/help/sequences">molecular weight</a>.<p><a href='/help/sequences_section' target='_top'>More...</a></p>Sequence (1+)i
<p>This subsection of the <a href="http://www.uniprot.org/help/sequences_section">Sequence</a> section indicates if the <a href="http://www.uniprot.org/help/canonical_and_isoforms">canonical sequence</a> displayed by default in the entry is complete or not.<p><a href='/help/sequence_status' target='_top'>More...</a></p>Sequence statusi: Complete.
<p>This subsection of the <a href="http://www.uniprot.org/help/sequences_section">Sequence</a> section indicates if the <a href="http://www.uniprot.org/help/canonical_and_isoforms">canonical sequence</a> displayed by default in the entry is in its mature form or if it represents the precursor.<p><a href='/help/sequence_processing' target='_top'>More...</a></p>Sequence processingi: The displayed sequence is further processed into a mature form.
This entry describes 1
<p>This subsection of the ‘Sequence’ section lists the alternative protein sequences (isoforms) that can be generated from the same gene by a single or by the combination of up to four biological events (alternative promoter usage, alternative splicing, alternative initiation and ribosomal frameshifting). Additionally, this section gives relevant information on each alternative protein isoform.<p><a href='/help/alternative_products' target='_top'>More...</a></p> isoform i produced by alternative splicing. AlignAdd to basketAdded to basket
Note:A number of isoforms are produced. Alternative splicing involves excision of the transmembrane or cytoplasmic domains.
This entry has 1 described isoform and 1 potential isoform that is computationally mapped.Show allAlign All
This isoform has been chosen as the 'canonical' sequence. All positional information in this entry refers to it. This is also the sequence that appears in the downloadable versions of the entry.
<p>The checksum is a form of redundancy check that is calculated
from the sequence. It is useful for tracking sequence updates.</p>
<p>It should be noted that while, in theory, two different sequences could
have the same checksum value, the likelihood that this would happen
is extremely low.</p>
<p>However UniProtKB may contain entries with identical sequences in case
of multiple genes (paralogs).</p>
<p>The checksum is computed as the sequence 64-bit Cyclic Redundancy Check value (CRC64)
using the generator polynomial: x<sup>64</sup> + x<sup>4</sup> + x<sup>3</sup> + x + 1.
The algorithm is described in the ISO 3309 standard.
</p>
<p class="publication">Press W.H., Flannery B.P., Teukolsky S.A. and Vetterling W.T.<br />
<strong>Cyclic redundancy and other checksums</strong><br />
<a href="http://www.nrbook.com/b/bookcpdf.php">Numerical recipes in C 2nd ed., pp896-902, Cambridge University Press (1993)</a>)</p>
Checksum:i22D0D78ECEC3EA04
<p>In eukaryotic reference proteomes, unreviewed entries that are likely to belong to the same gene are computationally mapped, based on gene identifiers from Ensembl, EnsemblGenomes and model organism databases.<p><a href='/help/gene_centric_isoform_mapping' target='_top'>More...</a></p>Computationally mapped potential isoform sequencesi
<p>The annotation score provides a heuristic measure of the annotation content of a UniProtKB entry or proteome. This score <strong>cannot</strong> be used as a measure of the accuracy of the annotation as we cannot define the ‘correct annotation’ for any given protein.<p><a href='/help/annotation_score' target='_top'>More...</a></p>
Experimental Info
Feature key
Position(s)
DescriptionActions
Graphical view
Length
<p>This subsection of the ‘Sequence’ section reports difference(s) between the canonical sequence (displayed by default in the entry) and the different sequence submissions merged in the entry. These various submissions may originate from different sequencing projects, different types of experiments, or different biological samples. Sequence conflicts are usually of unknown origin.<p><a href='/help/conflict' target='_top'>More...</a></p>Sequence conflicti
<p>This subsection of the ‘Sequence’ section describes natural variant(s) of the protein sequence.<p><a href='/help/variant' target='_top'>More...</a></p>Natural varianti
<p>This section provides links to proteins that are similar to the protein sequence(s) described in this entry at different levels of sequence identity thresholds (100%, 90% and 50%) based on their membership in UniProt Reference Clusters (<a href="http://www.uniprot.org/help/uniref">UniRef</a>).<p><a href='/help/similar_proteins_section' target='_top'>More...</a></p>Similar proteinsi
<p>This section is used to point to information related to entries and found in data collections other than UniProtKB.<p><a href='/help/cross_references_section' target='_top'>More...</a></p>Cross-referencesi
Sequence databases
Select the link destinations: EMBLi GenBanki DDBJi
<p>This section provides general information on the entry.<p><a href='/help/entry_information_section' target='_top'>More...</a></p>Entry informationi
<p>This subsection of the ‘Entry information’ section provides a mnemonic identifier for a UniProtKB entry, but it is not a stable identifier. Each reviewed entry is assigned a unique entry name upon integration into UniProtKB/Swiss-Prot.<p><a href='/help/entry_name' target='_top'>More...</a></p>Entry namei
CD8A_MOUSE
<p>This subsection of the ‘Entry information’ section provides one or more accession number(s). These are stable identifiers and should be used to cite UniProtKB entries. Upon integration into UniProtKB, each entry is assigned a unique accession number, which is called ‘Primary (citable) accession number’.<p><a href='/help/accession_numbers' target='_top'>More...</a></p>Accessioni
<p>This subsection of the ‘Entry information’ section shows the date of integration of the entry into UniProtKB, the date of the last sequence update and the date of the last annotation modification (‘Last modified’). The version number for both the entry and the <a href="http://www.uniprot.org/help/canonical_and_isoforms">canonical sequence</a> are also displayed.<p><a href='/help/entry_history' target='_top'>More...</a></p>Entry historyi
Integrated into UniProtKB/Swiss-Prot:
July 21, 1986
Last sequence update:
July 21, 1986
Last modified:
November 7, 2018
This is version 176 of the entry and version 1 of the sequence. See complete history.
<p>This subsection of the ‘Entry information’ section indicates whether the entry has been manually annotated and reviewed by UniProtKB curators or not, in other words, if the entry belongs to the Swiss-Prot section of UniProtKB (<strong>reviewed</strong>) or to the computer-annotated TrEMBL section (<strong>unreviewed</strong>).<p><a href='/help/entry_status' target='_top'>More...</a></p>Entry statusi
<p>This section contains any relevant information that doesn’t fit in any other defined sections<p><a href='/help/miscellaneous_section' target='_top'>More...</a></p>Miscellaneousi
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