HLA class II histocompatibility antigen gamma chain; HLA-DR antigens-associated invariant chain; Ia antigen-associated invariant chain; Ii; p33; CD74 (DHLAG)

Function

• associates with MHC class II alpha & MHC class II beta chains in ER but dissociates in GOLGI after glycosylation
• some MHC class II gamma chain integrates into plasma membrane
• invariant MHC class II antigen
• role in MHC class II antigen processing by stabilizing peptide-free class II alpha/beta heterodimers in a complex soon after their synthesis & directing transport of the complex from the endoplasmic reticulum to compartments where peptide loading of class II takes place
• nonamer composed of three alpha/beta/gamma heterotrimers

Structure

contains 1 thyroglobulin type-1 domain

Compartment

membrane

Alternative splicing

named isoforms=2

Expression

• B cells
• activated T cells
• macrophages
• activated endothelial cells
• epithelial cells

More general terms

• protein subunit
• glycoprotein
• CD antigen

Database

• UniProt: http://www.uniprot.org/uniprot/P04233.html
• Entrez gene: http://www.ncbi.nlm.nih.gov/sites/entrez?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=972
• OMIM: https://mirror.omim.org/entry/142790