Cd8a

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 similarity2 Publications

GO - Molecular functionⁱ

protein homodimerization activity
Source: MGI
Inferred from direct assayⁱ
- 15749886
protein kinase binding Source: MGI

View the complete GO annotation on QuickGO ...

GO - Biological processⁱ

cell surface receptor signaling pathway
Source: MGI
Inferred from direct assayⁱ
- 9208839
cytotoxic T cell differentiation
Source: MGI
Inferred from mutant phenotypeⁱ
- 1673361
defense response to virus
Source: MGI
Inferred from direct assayⁱ
- 17277142
positive regulation of calcium-mediated signaling
Source: MGI
Inferred from direct assayⁱ
- 9208839
T cell activation Source: MGI
T cell mediated immunity
Source: MGI
Inferred from mutant phenotypeⁱ
- 1673361

View the complete GO annotation on QuickGO ...

Keywordsⁱ

Biological process	Adaptive immunity, Immunity

Biological process

Adaptive immunity, Immunity

Enzyme and pathway databases

Reactomeⁱ	R-MMU-198933 Immunoregulatory interactions between a Lymphoid and a non-Lymphoid cell

Reactomeⁱ

R-MMU-198933 Immunoregulatory interactions between a Lymphoid and a non-Lymphoid cell

Names & Taxonomyⁱ

Protein namesⁱ	Recommended name: T-cell surface glycoprotein CD8 alpha chain Alternative name(s): T-cell surface glycoprotein Lyt-2 CD_antigen: CD8a
Gene namesⁱ	Name:Cd8a Synonyms:Lyt-2, Lyt2
Organismⁱ	Mus musculus (Mouse)
Taxonomic identifierⁱ	10090 [NCBI]
Taxonomic lineageⁱ	cellular organisms › Eukaryota › Opisthokonta › Metazoa › Eumetazoa › Bilateria › Deuterostomia › Chordata › Craniata › Vertebrata › Gnathostomata › Teleostomi › Euteleostomi › Sarcopterygii › Dipnotetrapodomorpha › Tetrapoda › Amniota › Mammalia › Theria › Eutheria › Boreoeutheria › Euarchontoglires › Glires › Rodentia › Myomorpha › Muroidea › Muridae › Murinae › Mus › Mus
Proteomesⁱ	UP000000589 Componentⁱ: Chromosome 6

Organism-specific databases

MGIⁱ	MGI:88346 Cd8a

Topology

Feature key	Position(s)	DescriptionActions	Length
Topological domainⁱ	28 – 196	ExtracellularSequence analysisAdd BLAST	169
Transmembraneⁱ	197 – 217	HelicalSequence analysisAdd BLAST	21
Topological domainⁱ	218 – 247	CytoplasmicSequence analysisAdd BLAST	30

Keywords - Cellular componentⁱ

Cell membrane, Membrane

Pathology & Biotechⁱ

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

PTM / Processingⁱ

Molecule processing

Feature key	Position(s)	DescriptionActions	Graphical view	Length
Signal peptideⁱ	1 – 27	Add BLAST		27
ChainⁱPRO_0000014639	28 – 247	T-cell surface glycoprotein CD8 alpha chainAdd BLAST		220

Amino acid modifications

Feature key	Position(s)	DescriptionActions	Length
Disulfide bondⁱ	53 ↔ 129	PROSITE-ProRule annotation1 Publication
Glycosylationⁱ	69	N-linked (GlcNAc...) asparagine1 Publication	1
Glycosylationⁱ	97	N-linked (GlcNAc...) asparagine	1
Glycosylationⁱ	150	N-linked (GlcNAc...) asparagine	1

Post-translational modificationⁱ

Palmitoylated, but association with CD8B seems to be more important for the enrichment of CdD8A in lipid rafts.By similarity

Phosphorylated in cytotoxic T-lymphocytes (CTLs) following activation.1 Publication

Keywords - PTMⁱ

Disulfide bond, Glycoprotein, Lipoprotein, Palmitate

Proteomic databases

EPDⁱ	P01731
MaxQB - The MaxQuant DataBase More...MaxQBⁱ	P01731
PaxDbⁱ	P01731
PRIDEⁱ	P01731

PTM databases

iPTMnetⁱ	P01731
PhosphoSitePlusⁱ	P01731

Expressionⁱ

Gene expression databases

Bgeeⁱ	ENSMUSG00000053977
CleanExⁱ	MM_CD8A
ExpressionAtlasⁱ	P01731 baseline and differential
Genevisibleⁱ	P01731 MM

Interactionⁱ

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 similarity2 Publications

Binary interactionsⁱ

With	Entry	#Exp.	IntAct	Notes
Lck	P06240	2	EBI-1433,EBI-1401

With

Entry

#Exp.

IntAct

Notes

Lck

P06240

2

EBI-1433,EBI-1401

GO - Molecular functionⁱ

protein homodimerization activity
Source: MGI
Inferred from direct assayⁱ
- 15749886
protein kinase binding Source: MGI

View the complete GO annotation on QuickGO ...

Protein-protein interaction databases

IntActⁱ	P01731, 4 interactors
Molecular INTeraction database More...MINTⁱ	P01731
STRINGⁱ	10090.ENSMUSP00000068123

Structureⁱ

Secondary structure

Legend: HelixTurnBeta strandPDB Structure known for this area

Show more details

Feature key	Position(s)	DescriptionActions	Length
Beta strandⁱ	33 – 39	Combined sources	7
Beta strandⁱ	41 – 43	Combined sources	3
Beta strandⁱ	49 – 57	Combined sources	9
Beta strandⁱ	63 – 71	Combined sources	9
Beta strandⁱ	78 – 83	Combined sources	6
Beta strandⁱ	85 – 87	Combined sources	3
Beta strandⁱ	90 – 92	Combined sources	3
Turnⁱ	94 – 97	Combined sources	4
Helixⁱ	98 – 100	Combined sources	3
Beta strandⁱ	102 – 107	Combined sources	6
Turnⁱ	108 – 110	Combined sources	3
Beta strandⁱ	111 – 118	Combined sources	8
Helixⁱ	121 – 123	Combined sources	3
Beta strandⁱ	125 – 133	Combined sources	9
Beta strandⁱ	136 – 139	Combined sources	4
Beta strandⁱ	143 – 147	Combined sources	5

3D structure databases

ProteinModelPortalⁱ	P01731
SMRⁱ	P01731
ModBaseⁱ	Search...
MobiDBⁱ	Search...

Miscellaneous databases

EvolutionaryTraceⁱ

P01731

Family & Domainsⁱ

Domains and Repeats

Feature key	Position(s)	DescriptionActions	Graphical view	Length
Domainⁱ	28 – 139	Ig-like V-typeAdd BLAST		112

Keywords - Domainⁱ

Immunoglobulin domain, Signal, Transmembrane, Transmembrane helix

Phylogenomic databases

eggNOGⁱ	ENOG410IWN3 Eukaryota ENOG410Z6EI LUCA
Ensembl GeneTree More...GeneTreeⁱ	ENSGT00510000048935
HOGENOMⁱ	HOG000004794
HOVERGENⁱ	HBG008488
InParanoidⁱ	P01731
KEGG Orthology (KO) More...KOⁱ	K06458
OMAⁱ	RVCKCPR
Database of Orthologous Groups More...OrthoDBⁱ	EOG091G0YIT
PhylomeDBⁱ	P01731
TreeFamⁱ	TF336070

Family and domain databases

Gene3Dⁱ	2.60.40.10, 1 hit
InterProⁱ	View protein in InterPro IPR015468 CD8_asu IPR007110 Ig-like_dom IPR036179 Ig-like_dom_sf IPR013783 Ig-like_fold IPR003599 Ig_sub IPR013106 Ig_V-set
PANTHERⁱ	PTHR10441 PTHR10441, 1 hit
Pfam protein domain database More...Pfamⁱ	View protein in Pfam PF07686 V-set, 1 hit
SMARTⁱ	View protein in SMART SM00409 IG, 1 hit SM00406 IGv, 1 hit
SUPFAMⁱ	SSF48726 SSF48726, 1 hit
PROSITEⁱ	View protein in PROSITE PS50835 IG_LIKE, 1 hit

Sequenceⁱ

Sequence statusⁱ: Complete.

Sequence processingⁱ: The displayed sequence is further processed into a mature form.

This entry describes 1 isoform ⁱ produced by alternative splicing. Align Add to basket Added to basket

Note: A number of isoforms are produced. Alternative splicing involves excision of the transmembrane or cytoplasmic domains.

Isoform 1 (identifier: P01731-1) [UniParc]FASTA Add to basket

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.

« Hide

        10         20         30         40         50
MASPLTRFLS LNLLLLGESI ILGSGEAKPQ APELRIFPKK MDAELGQKVD 
        60         70         80         90        100
LVCEVLGSVS QGCSWLFQNS SSKLPQPTFV VYMASSHNKI TWDEKLNSSK 
       110        120        130        140        150
LFSAMRDTNN KYVLTLNKFS KENEGYYFCS VISNSVMYFS SVVPVLQKVN 
       160        170        180        190        200
STTTKPVLRT PSPVHPTGTS QPQRPEDCRP RGSVKGTGLD FACDIYIWAP 
       210        220        230        240 
LAGICVALLL SLIITLICYH RSRKRVCKCP RPLVRQEGKP RPSEKIV

Length:247

Mass (Da):27,456

Last modified:July 21, 1986 - v1

Checksum:ⁱ22D0D78ECEC3EA04

GO

Experimental Info

Feature key	Position(s)	DescriptionActions	Graphical view	Length
Sequence conflictⁱ	81	Missing in AAA39477 (PubMed:3495785).Curated		1
Sequence conflictⁱ	81	Missing in CAA68352 (PubMed:3495785).Curated		1

Natural variant

Feature key	Position(s)	DescriptionActions	Graphical view	Length
Natural variantⁱ	105	M → V in strain: C.AKR.		1

Sequence databases

Select the link destinations: EMBLⁱ GenBankⁱ DDBJⁱ Links Updated	M12825 mRNA Translation: AAA39476.1 M16981 mRNA Translation: AAA39477.1 Different termination. M12052 mRNA Translation: AAA39478.1 Y00157 Genomic DNA Translation: CAA68352.2 M22064 Genomic DNA Translation: AAA39665.1 M12977 , M12819, M12975, M12976 Genomic DNA Translation: AAA39475.1
The Consensus CDS (CCDS) project More...CCDSⁱ	CCDS39507.1 [P01731-1]
PIRⁱ	A01998 RWMST2 A29523 A34954
NCBI Reference Sequences More...RefSeqⁱ	NP_001074579.1, NM_001081110.2 [P01731-1]
UniGeneⁱ	Mm.1858

Genome annotation databases

Ensemblⁱ	ENSMUST00000066747; ENSMUSP00000068123; ENSMUSG00000053977 [P01731-1]
GeneIDⁱ	12525
KEGGⁱ	mmu:12525
UCSC genome browser More...UCSCⁱ	uc009cgr.1 mouse [P01731-1]

Keywords - Coding sequence diversityⁱ

Alternative splicing

Similar proteinsⁱ

100% Identity
90% Identity
50% Identity

Protein	Similar proteins		Species	Score	Length
P01731	Uncharacterized protein (Fragment)		MOUSE		239
UPI000066D86A		MOUSE		122
UPI0000D7DE8D		MOUSE		123
UPI0001AF80E5		MOUSE		166
Cd8a protein		MOUSE		207

Protein	Similar proteins		Species	Score	Length
P01731	Uncharacterized protein (Fragment)		MOUSE		239
UPI000A31618C		MUSCR		243
UPI000066D86A		MOUSE		122
UPI0000D7DE8D		MOUSE		123
UPI0001AF80E5		MOUSE		166
+8

Protein	Similar proteins		Species	Score	Length
P01731	Uncharacterized protein (Fragment)		MOUSE		239
UPI000A31618C		MUSCR		243
T-cell surface glycoprotein CD8 alpha chain		RAT		236
UPI000812E4B1		MANJA		202
UPI000066D86A		MOUSE		122
+10

Cross-referencesⁱ

Sequence databases

Select the link destinations: EMBLⁱ GenBankⁱ DDBJⁱ Links Updated	M12825 mRNA Translation: AAA39476.1 M16981 mRNA Translation: AAA39477.1 Different termination. M12052 mRNA Translation: AAA39478.1 Y00157 Genomic DNA Translation: CAA68352.2 M22064 Genomic DNA Translation: AAA39665.1 M12977 , M12819, M12975, M12976 Genomic DNA Translation: AAA39475.1
The Consensus CDS (CCDS) project More...CCDSⁱ	CCDS39507.1 [P01731-1]
PIRⁱ	A01998 RWMST2 A29523 A34954
NCBI Reference Sequences More...RefSeqⁱ	NP_001074579.1, NM_001081110.2 [P01731-1]
UniGeneⁱ	Mm.1858

3D structure databases

Select the link destinations: Protein Data Bank Europe More...PDBeⁱ Protein Data Bank RCSB More...RCSB PDBⁱ Protein Data Bank Japan More...PDBjⁱ Links Updated	PDB entry	Method	Resolution (Å)	Chain	Positions	PDBsum
	1BQH	X-ray	2.80	G/H/I/K	28-156	[»]
	1NEZ	X-ray	2.10	G/H	28-149	[»]
	2ARJ	X-ray	2.88	Q/R	28-150	[»]
	2ATP	X-ray	2.40	A/C	28-149	[»]
	3B9K	X-ray	2.70	A/E	28-151	[»]
	3DMM	X-ray	2.60	C	23-188	[»]
ProteinModelPortalⁱ	P01731
SMRⁱ	P01731
ModBaseⁱ	Search...
MobiDBⁱ	Search...

Protein-protein interaction databases

IntActⁱ	P01731, 4 interactors
Molecular INTeraction database More...MINTⁱ	P01731
STRINGⁱ	10090.ENSMUSP00000068123

PTM databases

iPTMnetⁱ	P01731
PhosphoSitePlusⁱ	P01731

Proteomic databases

EPDⁱ	P01731
MaxQB - The MaxQuant DataBase More...MaxQBⁱ	P01731
PaxDbⁱ	P01731
PRIDEⁱ	P01731

Protocols and materials databases

Structural Biology Knowledgebase	Search...

Structural Biology Knowledgebase

Search...

Genome annotation databases

Ensemblⁱ	ENSMUST00000066747; ENSMUSP00000068123; ENSMUSG00000053977 [P01731-1]
GeneIDⁱ	12525
KEGGⁱ	mmu:12525
UCSC genome browser More...UCSCⁱ	uc009cgr.1 mouse [P01731-1]

Organism-specific databases

CTDⁱ	925
MGIⁱ	MGI:88346 Cd8a

Phylogenomic databases

eggNOGⁱ	ENOG410IWN3 Eukaryota ENOG410Z6EI LUCA
Ensembl GeneTree More...GeneTreeⁱ	ENSGT00510000048935
HOGENOMⁱ	HOG000004794
HOVERGENⁱ	HBG008488
InParanoidⁱ	P01731
KEGG Orthology (KO) More...KOⁱ	K06458
OMAⁱ	RVCKCPR
Database of Orthologous Groups More...OrthoDBⁱ	EOG091G0YIT
PhylomeDBⁱ	P01731
TreeFamⁱ	TF336070

Enzyme and pathway databases

Reactomeⁱ	R-MMU-198933 Immunoregulatory interactions between a Lymphoid and a non-Lymphoid cell

Reactomeⁱ

R-MMU-198933 Immunoregulatory interactions between a Lymphoid and a non-Lymphoid cell

Miscellaneous databases

EvolutionaryTraceⁱ	P01731
Protein Ontology More...PROⁱ	PR:P01731
SOURCEⁱ	Search...

Gene expression databases

Bgeeⁱ	ENSMUSG00000053977
CleanExⁱ	MM_CD8A
ExpressionAtlasⁱ	P01731 baseline and differential
Genevisibleⁱ	P01731 MM

Family and domain databases

Gene3Dⁱ	2.60.40.10, 1 hit
InterProⁱ	View protein in InterPro IPR015468 CD8_asu IPR007110 Ig-like_dom IPR036179 Ig-like_dom_sf IPR013783 Ig-like_fold IPR003599 Ig_sub IPR013106 Ig_V-set
PANTHERⁱ	PTHR10441 PTHR10441, 1 hit
Pfam protein domain database More...Pfamⁱ	View protein in Pfam PF07686 V-set, 1 hit
SMARTⁱ	View protein in SMART SM00409 IG, 1 hit SM00406 IGv, 1 hit
SUPFAMⁱ	SSF48726 SSF48726, 1 hit
PROSITEⁱ	View protein in PROSITE PS50835 IG_LIKE, 1 hit
ProtoNetⁱ	Search...

Entry informationⁱ

Entry nameⁱ	CD8A_MOUSE
Accessionⁱ	P01731Primary (citable) accession number: P01731
Entry historyⁱ	Integrated into UniProtKB/Swiss-Prot:	July 21, 1986
	Last sequence update:	July 21, 1986
	Last modified:	June 20, 2018
	This is version 174 of the entry and version 1 of the sequence. See complete history.
Entry statusⁱ	Reviewed (UniProtKB/Swiss-Prot)
Annotation program	Chordata Protein Annotation Program

Miscellaneousⁱ

Keywords - Technical termⁱ

3D-structure, Complete proteome, Reference proteome

Documents

MGD cross-references
Mouse Genome Database (MGD) cross-references in UniProtKB/Swiss-Prot
PDB cross-references
Index of Protein Data Bank (PDB) cross-references

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Help

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UniProtKB - P01731 (CD8A_MOUSE)

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T-cell surface glycoprotein CD8 alpha chain

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

<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

<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 - Biological processi

Enzyme and pathway databases

<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

Organism-specific databases

<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

Plasma membrane

Plasma Membrane

Other locations

Topology

<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 section describes post-translational modifications (PTMs) and/or processing events.<p><a href='/help/ptm_processing_section' target='_top'>More...</a></p>PTM / Processingi

Molecule processing

Amino acid modifications

Proteomic databases

PTM databases

<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

Gene expression databases

<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>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-protein interaction databases

<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

3D structure databases

Miscellaneous databases

<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

Phylogenomic databases

Family and domain databases

Experimental Info

Natural variant

Sequence databases

Genome annotation databases

<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

3D structure databases

Protein-protein interaction databases

PTM databases

Proteomic databases

Protocols and materials databases

Genome annotation databases

Organism-specific databases

Phylogenomic databases

Enzyme and pathway databases

Miscellaneous databases

Gene expression databases

Family and domain databases

<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 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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Functionⁱ

GO - Molecular functionⁱ

GO - Biological processⁱ

Names & Taxonomyⁱ

Subcellular locationⁱ

Pathology & Biotechⁱ

PTM / Processingⁱ

Expressionⁱ

Interactionⁱ

GO - Molecular functionⁱ

Structureⁱ

Family & Domainsⁱ

Cross-referencesⁱ

Entry informationⁱ

Miscellaneousⁱ