title: A dominant negative mutant beta 2-microglobulin blocks the extracellular folding of a major histocompatibility complex class I heavy chain.
abstract: The major histocompatibility complex class I (MHC1) molecule plays a crucial role in cytotoxic lymphocyte function. beta 2-Microglobulin (beta 2m) has been demonstrated to be both a structural component of the MHC1 complex and a chaperone-like molecule for MHC1 folding. beta 2m binding to an isolated alpha 3 domain of MHC1 heavy chain at micromolar concentrations has been shown to accurately model the biochemistry and thermodynamics of beta 2m-driven MHC1 folding. These results suggested a model in which the chaperone-like role of beta 2m is dependent on initial binding to the alpha 3 domain interface of MHC1 with beta 2m. Such a model predicts that a mutant beta 2m molecule with an intact MHC1 alpha 3 domain interaction but a defective MHC1 alpha 1 alpha 2 domain interaction would block beta2m-driven folding of MHC1. In this study we generated such a beta 2m mutant and demonstrated that it blocks MHC1 folding by normal beta 2m at the expected micromolar concentrations. Our data support an initial interaction of beta 2m with the MHC1 alpha 3 domain in MHC1 folding. In addition, the dominant negative mutant beta 2m can block T-cell functional responses to antigenic peptide and MHC1.
authors.affiliation: Division of Monoclonal Antibodies, Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, Maryland 20892, USA.
authors.forename: Dawn M
authors.initials: DM
authors.lastname: Hill
authors.forename: Tina
authors.initials: T
authors.lastname: Kasliwal
authors.forename: Elie
authors.initials: E
authors.lastname: Schwarz
authors.forename: Andrea M
authors.initials: AM
authors.lastname: Hebert
authors.forename: Trina
authors.initials: T
authors.lastname: Chen
authors.forename: Elena
authors.initials: E
authors.lastname: Gubina
authors.forename: Lei
authors.initials: L
authors.lastname: Zhang
authors.forename: Steven
authors.initials: S
authors.lastname: Kozlowski
mesh_terms: D019943:Amino Acid Substitution; D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D003001:Cloning, Molecular; D017931:DNA Primers; D005799:Genes, Dominant; D005805:Genes, MHC Class I; D015395:Histocompatibility Antigens Class I / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D016399:Lymphoma, T-Cell; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D016133:Polymerase Chain Reaction; D017510:Protein Folding; D017433:Protein Structure, Secondary; D011994:Recombinant Proteins / Q000378:metabolism; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology; D014162:Transfection; D014407:Tumor Cells, Cultured; D001613:beta 2-Microglobulin / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism
chemical_list: D017931:DNA Primers; D015395:Histocompatibility Antigens Class I; D011994:Recombinant Proteins; D001613:beta 2-Microglobulin