title: The human invariant chain is the core protein of the human class II-associated proteoglycan.
abstract: The human class II-associated chondroitin sulfate proteoglycan (CSPG) was analyzed biochemically and immunologically to determine a possible relationship with the human invariant chain (gamma 1) and its related components. The CSPG was purified by a three-step procedure involving associative ion-exchange chromatography, immunoprecipitation, and dissociative ion-exchange chromatography. Treatment of the CSPG with chondroitinase revealed core proteins of Mr approximately 46,000, 38,000, and 28,000, with the 38,000 species most highly represented. Tryptic peptide analysis revealed identity of the peptides of the 38,000 Mr core protein and gamma 1, and of the 28,000 Mr species and p25. The CSPG and its core proteins were shown to react directly with the mouse anti-human invariant chain monoclonal antibody VIC-Y1 and a rabbit antiserum produced against a synthetic peptide corresponding to the C-terminal end of invariant chain. These results demonstrate that the invariant chain is the core protein of the class II-associated CSPG. In addition, virtually all the CSPG was shown to be present on the cell surface.
authors.forename: K S
authors.initials: KS
authors.lastname: Giacoletto
authors.forename: A J
authors.initials: AJ
authors.lastname: Sant
authors.forename: C
authors.initials: C
authors.lastname: Bono
authors.forename: J
authors.initials: J
authors.lastname: Gorka
authors.forename: D M
authors.initials: DM
authors.lastname: O'Sullivan
authors.forename: V
authors.initials: V
authors.lastname: Quaranta
authors.forename: B D
authors.initials: BD
authors.lastname: Schwartz
mesh_terms: D000944:Antigens, Differentiation, B-Lymphocyte; D011508:Chondroitin Sulfate Proteoglycans / Q000032:analysis* / Q000276:immunology / Q000502:physiology; D002810:Chondroitinases and Chondroitin Lyases / Q000494:pharmacology; D000090266:Chromobox Protein Homolog 5; D004591:Electrophoresis, Polyacrylamide Gel; D000949:Histocompatibility Antigens Class II / Q000032:analysis*; D006801:Humans; D008715:Methionine / Q000378:metabolism; D008970:Molecular Weight; D011509:Proteoglycans / Q000032:analysis*; D012995:Solubility
chemical_list: D000944:Antigens, Differentiation, B-Lymphocyte; C000715594:CBX5 protein, human; D011508:Chondroitin Sulfate Proteoglycans; D000949:Histocompatibility Antigens Class II; D011509:Proteoglycans; C045084:invariant chain; D000090266:Chromobox Protein Homolog 5; D008715:Methionine; D002810:Chondroitinases and Chondroitin Lyases