title: Assembly of major histocompatibility complex class II subunits with invariant chain.
abstract: The highly polymorphic major histocompatibility complex class II (MHCII) polypeptides assemble in the ER with the assistance of invariant chain (Ii) chaperone. Ii binds to the peptide-binding pocket of MHCII heterodimers. We explored the mechanism how MHCII subunits attach to Ii. Expression with single alpha or beta subunits from three human HLA and two mouse H2 class II isotypes revealed that Ii co-isolates predominantly with the alpha polypeptide. Co-isolation with alpha chain requires the groove binding Ii-segment and depends on M91 of Ii. Immunoprecipitation of Ii from pulse chase labeled cells showed sequential assembly of alpha and beta chains.
authors.affiliation: Division of Immunobiology, Institute of Molecular Physiology, University of Bonn, Romerstrasse 164, 53117 Bonn, Germany.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Neumann
authors.forename: Norbert
authors.initials: N
authors.lastname: Koch
mesh_terms: D000818:Animals; D000944:Antigens, Differentiation, B-Lymphocyte / Q000378:metabolism*; D006682:HLA-DP Antigens / Q000378:metabolism; D006684:HLA-DR Antigens / Q000378:metabolism; D059811:HLA-DRB1 Chains; D000949:Histocompatibility Antigens Class II / Q000378:metabolism*; D006801:Humans; D047468:Immunoprecipitation; D051379:Mice; D018832:Molecular Chaperones / Q000378:metabolism*; D010455:Peptides / Q000378:metabolism
chemical_list: D000944:Antigens, Differentiation, B-Lymphocyte; D006682:HLA-DP Antigens; D006684:HLA-DR Antigens; D059811:HLA-DRB1 Chains; D000949:Histocompatibility Antigens Class II; C024138:I-E-antigen; D018832:Molecular Chaperones; D010455:Peptides; C045084:invariant chain