HLA-E Non-classical major histocompatibility class Ib molecule involved in immune self-nonself discrimination. In complex with B2M/beta-2-microglobulin binds nonamer self-peptides derived from the signal sequence of classical MHC class Ia molecules (VL9 peptides). Peptide-bound HLA-E-B2M heterotrimeric complex primarily functions as a ligand for natural killer (NK) cell inhibitory receptor KLRD1-KLRC1, enabling NK cells to monitor the expression of other MHC class I molecules in healthy cells and to tolerate self. Upon cellular stress, preferentially binds signal sequence-derived peptides from stress-induced chaperones and is no longer recognized by NK cell inhibitory receptor KLRD1-KLRC1, resulting in impaired protection from NK cells. Binds signal sequence-derived peptides from non-classical MHC class Ib HLA-G molecules and acts as a ligand for NK cell activating receptor KLRD1-KLRC2, likely playing a role in the generation and effector functions of adaptive NK cells and in maternal-fetal tolerance during pregnancy. Besides self-peptides, can also bind and present pathogen-derived peptides conformationally similar to VL9 peptides to alpha-beta T cell receptor (TCR) on unconventional CD8+ cytotoxic T cells, ultimately triggering antimicrobial immune response. (Microbial infection) Viruses like human cytomegalovirus have evolved an escape mechanism whereby virus-induced down-regulation of host MHC class I molecules is coupled to the binding of viral peptides to HLA-E, restoring HLA-E expression and inducing HLA-E-dependent NK cell immune tolerance to infected cells. Belongs to the MHC class I family. Expressed in secretory endometrial cells during pregnancy (at protein level). The expression in nonlymphoid tissues is restricted to endothelial cells from all types of vessels, including arteries, veins, capillaries, and lymphatics (at protein level). In lymphoid organs, it is mainly expressed in endothelial venules, B and T cells, monocytes, macrophages, NK cells and megakaryocytes (at protein level). Note: This description may include information from UniProtKB.
Protein type: Membrane protein, integral
Chromosomal Location of Human Ortholog: 17 B1|17 18.86 cM
Cellular Component:  cell surface; external side of plasma membrane; extracellular space; integral component of membrane; membrane; MHC class I protein complex; MHC class Ib protein complex; plasma membrane
Molecular Function:  beta-2-microglobulin binding; MHC class I protein binding; natural killer cell lectin-like receptor binding; peptide antigen binding; signaling receptor binding; T cell receptor binding
Biological Process:  adaptive immune response; antibacterial humoral response; antigen processing and presentation of endogenous peptide antigen via MHC class I via ER pathway, TAP-independent; antigen processing and presentation of endogenous peptide antigen via MHC class Ib; antigen processing and presentation of endogenous peptide antigen via MHC class Ib via ER pathway, TAP-dependent; antigen processing and presentation of exogenous peptide antigen via MHC class Ib; antigen processing and presentation of peptide antigen via MHC class I; CD8-positive, alpha-beta T cell activation; defense response to Gram-positive bacterium; immune response; immune system process; inner ear development; natural killer cell tolerance induction; negative regulation of natural killer cell mediated cytotoxicity; positive regulation of antibody-dependent cellular cytotoxicity; positive regulation of CD8-positive, alpha-beta T cell activation; positive regulation of CD8-positive, alpha-beta T cell proliferation; positive regulation of immunoglobulin secretion; positive regulation of interleukin-13 production; positive regulation of interleukin-4 production; positive regulation of natural killer cell cytokine production; positive regulation of natural killer cell mediated cytotoxicity; positive regulation of natural killer cell mediated immunity; positive regulation of natural killer cell proliferation; positive regulation of T cell mediated cytotoxicity; positive regulation of TRAIL production; positive regulation of tumor necrosis factor production; protection from natural killer cell mediated cytotoxicity; regulation of natural killer cell mediated immunity
Reference #:  P06339 (UniProtKB)
Alt. Names/Synonyms: 37b; 37c; H-2 class I histocompatibility antigen, D-37 alpha chain; H-2T23; H2-K1; H2-Qa1; H2-T23; HA15; histocompatibility 2, T region locus 23; HLA-E; MGC117681; MHC class I antigen Qa1; MHC class II antigen K; MHC classIb Qa1; OTTMUSP00000015895; Qa-; Qa-1; Qa-1(b); Qa1; Qed-1; T18c; T18c(37); T23b; T23d
Gene Symbols: H2-T23
Molecular weight: 40,875 Da
Basal Isoelectric point: 5.91  Predict pI for various phosphorylation states
Select Structure to View Below

HLA-E

Protein Structure Not Found.


Cross-references to other databases:  STRING  |  Reactome  |  BioGPS  |  Pfam  |  RCSB PDB  |  Phospho.ELM  |  UniProtKB  |  Entrez-Gene  |  GenPept  |  Ensembl Gene