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. A chromosomal aberration involving CD74 is found in a non-small cell lung tumor. Results in the formation of a CD74- ROS1 chimeric protein. 3 isoforms of the human protein are produced by alternative splicing. Note: This description may include information from UniProtKB.
Protein type: Endoplasmic reticulum; Membrane protein, integral; Receptor, cytokine
Cellular Component: cell surface; external side of plasma membrane; Golgi membrane; integral component of membrane; intracellular; lysosomal lumen; lysosomal membrane; membrane; MHC class II protein complex; multivesicular body; plasma membrane; trans-Golgi network membrane; vacuole
Molecular Function: amyloid-beta binding; CD4 receptor binding; cytokine binding; hematopoietin/interferon-class (D200-domain) cytokine receptor activity; identical protein binding; MHC class II protein binding; MHC class II protein binding, via antigen binding groove; nitric-oxide synthase binding; protein binding
Biological Process: activation of MAPK activity; antigen processing and presentation of endogenous antigen; antigen processing and presentation of exogenous peptide antigen via MHC class II; cell proliferation; chaperone cofactor-dependent protein folding; defense response; immunoglobulin mediated immune response; intracellular protein transport; leukocyte migration; negative regulation of apoptosis; negative regulation of DNA damage response, signal transduction by p53 class mediator; negative regulation of mature B cell apoptosis; negative regulation of peptide secretion; negative regulation of T cell differentiation; negative thymic T cell selection; positive regulation of B cell proliferation; positive regulation of cytokine and chemokine mediated signaling pathway; positive regulation of dendritic cell antigen processing and presentation; positive regulation of fibroblast proliferation; positive regulation of I-kappaB kinase/NF-kappaB signaling; positive regulation of kinase activity; positive regulation of MAPK cascade; positive regulation of monocyte differentiation; positive regulation of peptidyl-tyrosine phosphorylation; positive regulation of protein phosphorylation; positive regulation of T cell differentiation; positive regulation of transcription, DNA-templated; positive regulation of type 2 immune response; positive regulation of virion penetration into host cell; positive thymic T cell selection; prostaglandin biosynthetic process; protein complex assembly; protein heterotetramerization; regulation of macrophage activation; signal transduction; T cell selection
Alt. Names/Synonyms: CD74; CD74 antigen (invariant polypeptide of major histocompatibility complex, class II antigen-associated); CD74 molecule, major histocompatibility complex, class II invariant chain; DHLAG; gamma chain of class II antigens; HG2A; HLA class II histocompatibility antigen gamma chain; HLA-DR antigens-associated invariant chain; HLA-DR-gamma; HLADG; Ia antigen-associated invariant chain; Ia-associated invariant chain; Ia-GAMMA; MHC HLA-DR gamma chain; p33