|2B17_HUMAN » HLA class II histocompatibility antigen, DRB1-7 beta chain » MHC class II antigen DRB1*7;DR-7; DR7;|
|Hydrophobic Thickness||33.2 ± 1.4 Å|
|Tilt Angle||1 ± 0°|
|Links||UniProtKB, Pfam, Interpro, iHOP, STRING, HGNC, Reactome|
|TM Segments||228-250 (222-253)|
Allograft rejection (KEGG)
Autoimmune thyroid disease (KEGG)
Cell adhesion molecules (KEGG)
Epstein-Barr virus infection (KEGG)
Graft-versus-host disease (KEGG)
Hematopoietic cell lineage (KEGG)
Herpes simplex infection (KEGG)
HTLV-I infection (KEGG)
Immune System (Reactome)
Influenza A (KEGG)
Rheumatoid arthritis (KEGG)
Systemic lupus erythematosus (KEGG)
Type I diabetes mellitus (KEGG)
Viral myocarditis (KEGG)
|UniProt annotation for 2B17_HUMAN » HLA class II histocompatibility antigen, DRB1-7 beta chain|
|FUNCTION: Binds peptides derived from antigens that access the endocytic route of antigen presenting cells (APC) and presents them on the cell surface for recognition by the CD4 T-cells. The peptide binding cleft accommodates peptides of 10-30 residues. The peptides presented by MHC class II molecules are generated mostly by degradation of proteins that access the endocytic route; where they are processed by lysosomal proteases and other hydrolases. Exogenous antigens that have been endocytosed by the APC are thus readily available for presentation via MHC II molecules; and for this reason this antigen presentation pathway is usually referred to as exogenous. As membrane proteins on their way to degradation in lysosomes as part of their normal turn-over are also contained in the endosomal/lysosomal compartments; exogenous antigens must compete with those derived from endogenous components. Autophagy is also a source of endogenous peptides; autophagosomes constitutively fuse with MHC class II loading compartments. In addition to APCs; other cells of the gastrointestinal tract; such as epithelial cells; express MHC class II molecules and CD74 and act as APCs; which is an unusual trait of the GI tract. To produce a MHC class II molecule that presents an antigen; three MHC class II molecules (heterodimers of an alpha and a beta chain) associate with a CD74 trimer in the ER to form a heterononamer. Soon after the entry of this complex into the endosomal/lysosomal system where antigen processing occurs; CD74 undergoes a sequential degradation by various proteases; including CTSS and CTSL; leaving a small fragment termed CLIP (class-II-associated invariant chain peptide). The removal of CLIP is facilitated by HLA-DM via direct binding to the alpha-beta-CLIP complex so that CLIP is released. HLA-DM stabilizes MHC class II molecules until primary high affinity antigenic peptides are bound. The MHC II molecule bound to a peptide is then transported to the cell membrane surface. In B-cells; the interaction between HLA-DM and MHC class II molecules is regulated by HLA-DO. Primary dendritic cells (DCs) also to express HLA-DO. Lysosomal microenvironment has been implicated in the regulation of antigen loading into MHC II molecules; increased acidification produces increased proteolysis and efficient peptide loading. SUBUNIT: Heterodimer of an alpha and a beta subunit; also referred as MHC class II molecule. In the endoplasmic reticulum (ER) it forms a heterononamer; 3 MHC class II molecules bind to a CD74 homotrimer (also known as invariant chain or HLA class II histocompatibility antigen gamma chain). In the endosomal/lysosomal system; CD74 undergoes sequential degradation by various proteases; leaving a small fragment termed CLIP on each MHC class II molecule. MHC class II molecule interacts with HLA_DM, and HLA_DO in B-cells, in order to release CLIP and facilitate the binding of antigenic peptides.|
|UniProt features for 2B17_HUMAN » HLA class II histocompatibility antigen, DRB1-7 beta chain|
SIGNAL 1 29 |
CHAIN 30 266 HLA class II histocompatibility antigen, DRB1-7 beta chain.
DOMAIN 126 216 Ig-like C1-type.
REGION 30 124 Beta-1.
REGION 125 227 Beta-2.
DISULFID 44 108 By similarity.
DISULFID 146 202 By similarity.
CROSSLNK 254 254 Glycyl lysine isopeptide (Lys-Gly) (interchain with G-Cter in ubiquitin) (By similarity).
|Amino Acid Sequence for 2B17_HUMAN » HLA class II histocompatibility antigen, DRB1-7 beta chain|
|MVCLKLPGGS CMAALTVTLM VLSSPLALAG DTQPRFLWQG KYKCHFFNGT ERVQFLERLF YNQEEFVRFD SDVGEYRAVT ELGRPVAESW NSQKDILEDR RGQVDTVCRH NYGVGESFTV QRRVHPEVTV YPAKTQPLQH HNLLVCSVSG FYPGSIEVRW FRNGQEEKAG VVSTGLIQNG DWTFQTLVML ETVPRSGEVY TCQVEHPSVM SPLTVEWRAR SESAQSKMLS GVGGFVLGLL FLGAGLFIYF RNQKGHSGLQ PTGFLS|