Protein: HLA class I histocompatibility antigen, B alpha chain (Human leukocyte antigen B) (HLA-B) (P01889)
Organism: Homo sapiens (Human)
Function: Antigen-presenting major histocompatibility complex class I (MHCI) molecule. In complex with B2M/beta 2 microglobulin displays primarily viral and tumor-derived peptides on antigen-presenting cells for recognition by alpha-beta T cell receptor (TCR) on HLA-B-restricted CD8-positive T cells, guiding antigen-specific T cell immune response to eliminate infected or transformed cells. May also present self-peptides derived from the signal sequence of secreted or membrane proteins, although T cells specific for these peptides are usually inactivated to prevent autoreactivity. Both the peptide and the MHC molecule are recognized by TCR, the peptide is responsible for the fine specificity of antigen recognition and MHC residues account for the MHC restriction of T cells. Typically presents intracellular peptide antigens of 8 to 13 amino acids that arise from cytosolic proteolysis via constitutive proteasome and IFNG-induced immunoproteasome. Can bind different peptides containing allele-specific binding motifs, which are mainly defined by anchor residues at position 2 and 9.
Subcellular location: Cell membrane {ECO:0000269|PubMed:25480565, ECO:0000269|PubMed:26439010, ECO:0000269|PubMed:9620674}; Single-pass type I membrane protein {ECO:0000255}. Endoplasmic reticulum membrane {ECO:0000305|PubMed:9620674}; Single-pass type I membrane protein {ECO:0000255}.
Sequence: MLVMAPRTVLLLLSAALALTETWAGSHSMRYFYTSVSRPGRGEPRFISVGYVDDTQFVRFDSDAASPREEPRAPWIEQEGPEYWDRNTQIYKAQAQTDRESLRNLRGYYNQSEAGSHTLQSMYGCDVGPDGRLLRGHDQYAYDGKDYIALNEDLRSWTAADTAAQITQRKWEAAREAEQRRAYLEGECVEWLRRYLENGKDKLERADPPKTHVTHHPISDHEATLRCWALGFYPAEITLTWQRDGEDQTQDTELVETRPAGDRTFQKWAAVVVPSGEEQRYTCHVQHEGLPKPLTLRWEPSSQSTVPIVGIVAGLAVLAVVVIGAVVAAVMCRRKSSGGKGGSYSQAACSDSAQGSDVSLTA
InterPro domains: - IPR011162: MHC classes I/II-like antigen recognition protein (homologous_superfamily) [26-205]
- IPR036179: Immunoglobulin-like domain superfamily (homologous_superfamily) [208-300]
- IPR050208: Antigen-presenting and immune regulatory MHC class I-related (family) [14-336]
- IPR010579: MHC class I, alpha chain, C-terminal (domain) [337-362]
- IPR011161: MHC class I-like antigen recognition-like (domain) [25-203]
- IPR013783: Immunoglobulin-like fold (homologous_superfamily) [206-308]
- IPR007110: Immunoglobulin-like domain (domain) [209-295]
- IPR037055: MHC class I-like antigen recognition-like superfamily (homologous_superfamily) [24-205]
- IPR001039: MHC class I alpha chain, alpha1 alpha2 domains (domain) [83-199]
- IPR003006: Immunoglobulin/major histocompatibility complex, conserved site (conserved_site) [281-287]
- IPR003597: Immunoglobulin C1-set (domain) [219-293]
Interaction partners: - Killer cell immunoglobulin-like receptor 3DL1
- HLA class I histocompatibility antigen, A alpha chain
- Beta-2-microglobulin
- Killer cell immunoglobulin-like receptor 3DL2
- HLA class I histocompatibility antigen, C alpha chain
- Tapasin
- T-cell surface glycoprotein CD8 alpha chain
- HLA class I histocompatibility antigen, alpha chain E
- Leukocyte immunoglobulin-like receptor subfamily B member 2
- Leukocyte immunoglobulin-like receptor subfamily B member 1
Gene Ontology annotations:
Molecular Function (MF): GO:0003674 (molecular function), GO:0005488 (binding), GO:0003823 (antigen binding), GO:0033218 (amide binding), GO:0005515 (protein binding), GO:0042277 (peptide binding), GO:0042605 (peptide antigen binding)
Biological Process (BP): GO:0008150 (biological process), GO:0002376 (immune system process), GO:0019882 (antigen processing and presentation), GO:0048002 (antigen processing and presentation of peptide antigen), GO:0019883 (antigen processing and presentation of endogenous antigen), GO:0002483 (antigen processing and presentation of endogenous peptide antigen), GO:0002474 (antigen processing and presentation of peptide antigen via MHC class I)
Cellular Component (CC): GO:0005575 (cellular component), GO:0110165 (cellular anatomical entity), GO:0032991 (protein-containing complex), GO:0098552 (side of membrane), GO:0009986 (cell surface), GO:0031984 (organelle subcompartment), GO:0005622 (intracellular anatomical structure), GO:0043226 (organelle), GO:0016020 (membrane), GO:0071944 (cell periphery), GO:0098796 (membrane protein complex), GO:0005615 (extracellular space), GO:0005737 (cytoplasm), GO:0012505 (endomembrane system), GO:0005576 (extracellular region), GO:0031410 (cytoplasmic vesicle), GO:0043229 (intracellular organelle), GO:0005768 (endosome), GO:0098576 (lumenal side of membrane), GO:0098797 (plasma membrane protein complex), GO:0005794 (Golgi apparatus), GO:0043227 (membrane-bounded organelle), GO:0005886 (plasma membrane), GO:0031090 (organelle membrane), GO:0043230 (extracellular organelle), GO:0030133 (transport vesicle), GO:0098827 (endoplasmic reticulum subcompartment), GO:0042175 (nuclear outer membrane-endoplasmic reticulum membrane network), GO:0005783 (endoplasmic reticulum), GO:0070062 (extracellular exosome), GO:0055037 (recycling endosome), GO:0042611 (MHC protein complex), GO:0030658 (transport vesicle membrane), GO:0030139 (endocytic vesicle), GO:0005769 (early endosome), GO:0098553 (lumenal side of endoplasmic reticulum membrane), GO:0030659 (cytoplasmic vesicle membrane), GO:0043231 (intracellular membrane-bounded organelle), GO:0098588 (bounding membrane of organelle), GO:0012506 (vesicle membrane), GO:0065010 (extracellular membrane-bounded organelle), GO:0030135 (coated vesicle), GO:0005789 (endoplasmic reticulum membrane), GO:0010008 (endosome membrane), GO:0031982 (vesicle), GO:0000139 (Golgi membrane), GO:0030666 (endocytic vesicle membrane), GO:1903561 (extracellular vesicle), GO:0030134 (COPII-coated ER to Golgi transport vesicle), GO:0030662 (coated vesicle membrane), GO:0012507 (ER to Golgi transport vesicle membrane), GO:0097708 (intracellular vesicle), GO:0031901 (early endosome membrane), GO:0045335 (phagocytic vesicle), GO:0055038 (recycling endosome membrane), GO:0030670 (phagocytic vesicle membrane)