P41688 · CD8A_FELCA
- ProteinT-cell surface glycoprotein CD8 alpha chain
- GeneCD8A
- StatusUniProtKB reviewed (Swiss-Prot)
- Amino acids239 (go to sequence)
- Protein existenceEvidence at transcript level
- Annotation score3/5
Function
function
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.
GO annotations
all annotations | all molecular function | virus receptor activity | dna binding | rna binding | cytoskeletal motor activity | catalytic activity | gtpase activity | structural molecule activity | transporter activity | cytoskeletal protein binding | lipid binding | cyclase activity | antioxidant activity | oxidoreductase activity | transferase activity | hydrolase activity | lyase activity | isomerase activity | ligase activity | protein tag activity | cargo receptor activity | histone binding | protein folding chaperone | translation regulator activity | nutrient reservoir activity | receptor ligand activity | molecular transducer activity | molecular adaptor activity | toxin activity | cell adhesion mediator activity | molecular function regulator activity | virus coreceptor activity | catalytic activity, acting on a protein | catalytic activity, acting on dna | catalytic activity, acting on rna | molecular carrier activity | transcription regulator activity | general transcription initiation factor activity | molecular sensor activity | molecular sequestering activity | atp-dependent activity | other molecular function | all biological process | mitotic cell cycle | cytokinesis | cytoplasmic translation | immune system process | muscle system process | circulatory system process | renal system process | respiratory system process | carbohydrate metabolic process | generation of precursor metabolites and energy | dna replication | dna repair | dna recombination | chromatin organization | dna-templated transcription | regulation of dna-templated transcription | trna metabolic process | protein folding | protein glycosylation | amino acid metabolic process | modified amino acid metabolic process | lipid metabolic process | vitamin metabolic process | sulfur compound metabolic process | intracellular protein transport | nucleocytoplasmic transport | autophagy | inflammatory response | mitochondrion organization | cytoskeleton organization | microtubule-based movement | peroxisome organization | lysosome organization | chromosome segregation | cell adhesion | establishment or maintenance of cell polarity | programmed cell death | photosynthesis | mrna metabolic process | snrna metabolic process | vesicle-mediated transport | reproductive process | digestive system process | signaling | cell differentiation | protein catabolic process | extracellular matrix organization | regulatory ncrna-mediated gene silencing | telomere organization | cell junction organization | wound healing | ribosome biogenesis | cilium organization | anatomical structure development | cell motility | nervous system process | endocrine process | protein maturation | transmembrane transport | nucleobase-containing small molecule metabolic process | hepaticobiliary system process | membrane organization | protein-containing complex assembly | cell wall organization or biogenesis | nitrogen cycle metabolic process | protein localization to plasma membrane | defense response to other organism | detoxification | meiotic nuclear division | mitotic nuclear division | mitochondrial gene expression | carbohydrate derivative metabolic process | other biological process | all cellular component | nuclear chromosome | extracellular region | extracellular space | cell wall | nucleus | nuclear envelope | nucleoplasm | chromosome | nucleolus | mitochondrion | lysosome | endosome | vacuole | peroxisome | endoplasmic reticulum | golgi apparatus | lipid droplet | microtubule organizing center | cytosol | ribosome | cytoskeleton | plasma membrane | cilium | plastid | thylakoid | external encapsulating structure | extracellular matrix | cytoplasmic vesicle | organelle | other cellular component | |||
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Aspect | Term | |
---|---|---|
Cellular Component | external side of plasma membrane | |
Biological Process | cell surface receptor signaling pathway | |
Biological Process | cytotoxic T cell differentiation | |
Biological Process | T cell mediated immunity |
Keywords
- Biological process
Names & Taxonomy
Protein names
- Recommended nameT-cell surface glycoprotein CD8 alpha chain
- CD Antigen Name
Gene names
Organism names
- Taxonomic lineageEukaryota > Metazoa > Chordata > Craniata > Vertebrata > Euteleostomi > Mammalia > Eutheria > Laurasiatheria > Carnivora > Feliformia > Felidae > Felinae > Felis
Accessions
- Primary accessionP41688
Proteomes
Subcellular Location
UniProt Annotation
GO Annotation
Cell membrane ; Single-pass type I membrane protein
Note: CD8A localizes to lipid rafts only when associated with its partner CD8B.
Features
Showing features for topological domain, transmembrane.
Type | ID | Position(s) | Description | |||
---|---|---|---|---|---|---|
Topological domain | 22-188 | Extracellular | ||||
Sequence: AGPSPFRLSPVRVEGRLGQRVELQCEVLLSSAAPGCTWLFQKNEPAARPIFLAYLSRSRTKLAEELDPKQISGQRIQDTLYSLTLHRFRKEEEGYYFCSVVSNSVLYFSAFVPVFLPVKPTTTPAPRPPTQAPITTSQRVSLRPGTCQPSAGSTVEASGLDLSCDIY | ||||||
Transmembrane | 189-210 | Helical | ||||
Sequence: IWAPLAGTCAFLLLSLVITVIC | ||||||
Topological domain | 211-239 | Cytoplasmic | ||||
Sequence: NHRNRRRVCKCPRPVVRAGGKPSPSERYV |
Keywords
- Cellular component
PTM/Processing
Features
Showing features for signal, chain, disulfide bond, lipidation.
Type | ID | Position(s) | Description | |||
---|---|---|---|---|---|---|
Signal | 1-21 | |||||
Sequence: MASPVTAQLLPLALLLHAAAA | ||||||
Chain | PRO_0000014637 | 22-239 | T-cell surface glycoprotein CD8 alpha chain | |||
Sequence: AGPSPFRLSPVRVEGRLGQRVELQCEVLLSSAAPGCTWLFQKNEPAARPIFLAYLSRSRTKLAEELDPKQISGQRIQDTLYSLTLHRFRKEEEGYYFCSVVSNSVLYFSAFVPVFLPVKPTTTPAPRPPTQAPITTSQRVSLRPGTCQPSAGSTVEASGLDLSCDIYIWAPLAGTCAFLLLSLVITVICNHRNRRRVCKCPRPVVRAGGKPSPSERYV | ||||||
Disulfide bond | 46↔119 | |||||
Sequence: CEVLLSSAAPGCTWLFQKNEPAARPIFLAYLSRSRTKLAEELDPKQISGQRIQDTLYSLTLHRFRKEEEGYYFC | ||||||
Lipidation | 210 | S-palmitoyl cysteine | ||||
Sequence: C |
Post-translational modification
Palmitoylated, but association with CD8B seems to be more important for the enrichment of CD8A in lipid rafts.
O-glycosylated.
Phosphorylated in cytotoxic T-lymphocytes (CTLs) following activation.
Keywords
- PTM
Proteomic databases
Interaction
Subunit
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.
Protein-protein interaction databases
Structure
Family & Domains
Features
Showing features for domain.
Type | ID | Position(s) | Description | |||
---|---|---|---|---|---|---|
Domain | 25-139 | Ig-like V-type | ||||
Sequence: SPFRLSPVRVEGRLGQRVELQCEVLLSSAAPGCTWLFQKNEPAARPIFLAYLSRSRTKLAEELDPKQISGQRIQDTLYSLTLHRFRKEEEGYYFCSVVSNSVLYFSAFVPVFLPV |
Keywords
- Domain
Phylogenomic databases
Family and domain databases
Sequence
- Sequence statusComplete
- Sequence processingThe displayed sequence is further processed into a mature form.
- Length239
- Mass (Da)26,120
- Last updated1995-11-01 v1
- ChecksumF9A171820E8FF1BC
Keywords
- Technical term
Sequence databases
Nucleotide Sequence | Protein Sequence | Molecule Type | Status | |
---|---|---|---|---|
D16536 EMBL· GenBank· DDBJ | BAA03973.1 EMBL· GenBank· DDBJ | mRNA | ||
AB000485 EMBL· GenBank· DDBJ | BAA19126.1 EMBL· GenBank· DDBJ | mRNA |