The protein encoded by this gene associates with class II major histocompatibility complex (MHC) and is an important chaperone that regulates antigen presentation for immune response. It also serves as cell surface receptor for the cytokine macrophage migration inhibitory factor (MIF) which, when bound to the encoded protein, initiates survival pathways and cell proliferation. This protein also interacts with amyloid precursor protein (APP) and suppresses the production of amyloid beta (Abeta). Multiple alternatively spliced transcript variants encoding different isoforms have been identified. [provided by RefSeq, Aug 2011]
Function:
Plays a critical role in MHC class II antigen processing by stabilizing peptide-free class II alpha/beta heterodimers in a complex soon after their synthesis and directing transport of the complex from the endoplasmic reticulum to the endosomal/lysosomal system where the antigen processing and binding of antigenic peptides to MHC class II takes place. Serves as cell surface receptor for the cytokine MIF.
Subunit:
Homotrimer. In the endoplasmic reticulum (ER) it forms a heterononameric MHC II-Ii complex: 3 MHC class II molecules (heterodimers of an alpha and a beta subunit) bind to the CD74 homotrimer (also known as invariant chain or HLA class II histocompatibility antigen gamma chain). In the endosomal/lysosomal system, the CD74 component undergoes sequential degradation by various proteases, including CTSS and CTSL, leaving a small fragment termed CLIP (class-II-associated invariant chain peptide) attached to the MHC class II molecule (alpha-beta-CLIP complex). This processed complex interacts with HLA_DM and HLA_DO heterodimers in order to release CLIP and facilitate the binding of antigenic peptides to the MHC class II molecules.
Subcellular Location:
Cell membrane; Single-pass type II membrane protein (Potential). Endoplasmic reticulum membrane. Golgi apparatus, trans-Golgi network. Endosome. Lysosome. Note=Transits through a number of intracellular compartments in the endocytic pathway. It can either undergo proteolysis or reach the cell membrane.
Post-translational modifications:
N- and O-glycosylated. O-glycosylated with core 1 or possibly core 8 glycans.
DISEASE : Note=A chromosomal aberration involving CD74 is found in a non-small cell lung tumor. Results in the formation of a CD74-ROS1 chimeric protein.
Similarity:
Contains 1 thyroglobulin type-1 domain.
SWISS:
P04233
Gene ID:
972
Database links:
Entrez Gene: 972 Human
Entrez Gene: 16149 Mouse
Omim: 142790 Human
SwissProt: P04233 Human
SwissProt: P04441 Mouse
Unigene: 436568 Human
CD74表达于所有B细胞和某些T细胞亚类（MHC II阳性），具有几种异构体形式（33，35和41kDa），是HLA-DR的恒定链。该抗体主要用于标记生发中心及外套B细胞（80%）和R-S细胞（70%）以及少数T细胞（20%），常与其它B细胞标记如CD20或CD45RA联合检测，用于B细胞淋巴瘤的辅助诊断。
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