title: Subproteomic analysis of metal-interacting proteins in human B cells.
abstract: Metal-protein interactions are vitally important in all living organisms. Metalloproteins, including structural proteins and metabolic enzymes, participate in energy transfer and redox reactions or act as metallochaperones in metal trafficking. Among metal-associated diseases, T cell mediated allergy to nickel (Ni) represents the most common form of human contact hypersensitivity. With the aim to elucidate disease-underlying mechanisms such as Ni-specific T cell activation, we initiated a proteomic approach to identify Ni-interacting proteins in human B cells. As antigen presenting cells, B cells are capable of presenting MHC-associated Ni-epitopes to T cells, a prerequisite for hapten-specific T cell activation. Using metal-affinity enrichment, 2-DE and MS, 22 Ni-interacting proteins were identified. In addition to known Ni-binding molecules such as tubulin, actin or cullin-2, we unexpectedly discovered that at least nine of these 22 proteins belong to stress-inducible heat shock proteins or chaperonins. Enrichment was particularly effective for the hetero-oligomeric TRiC/CCT complex, which is involved in MHC class I processing. Blue Native/SDS electrophoresis analysis revealed that Ni-NTA-beads specifically retained the complete protein machinery, including the associated chaperonin substrate tubulin. The apparent Ni-affinity of heat shock proteins suggests a new function of these molecules in human Ni allergy, by linking innate and adaptive immune responses.
authors.affiliation: Max-Planck Institute for Immunobiology, Freiburg, Germany.
authors.forename: Kirsten
authors.initials: K
authors.lastname: Heiss
authors.forename: Christof
authors.initials: C
authors.lastname: Junkes
authors.forename: Nelson
authors.initials: N
authors.lastname: Guerreiro
authors.forename: Mahima
authors.initials: M
authors.lastname: Swamy
authors.forename: Margarita M
authors.initials: MM
authors.lastname: Camacho-Carvajal
authors.forename: Wolfgang W A
authors.initials: WW
authors.lastname: Schamel
authors.forename: Ian D
authors.initials: ID
authors.lastname: Haidl
authors.forename: Doris
authors.initials: D
authors.lastname: Wild
authors.forename: Hans Ulrich
authors.initials: HU
authors.lastname: Weltzien
authors.forename: Hermann-Josef
authors.initials: HJ
authors.lastname: Thierse
mesh_terms: D001402:B-Lymphocytes / Q000378:metabolism*; D015153:Blotting, Western; D002460:Cell Line; D002846:Chromatography, Affinity; D015180:Electrophoresis, Gel, Two-Dimensional; D006801:Humans; D008670:Metals / Q000378:metabolism*; D011485:Protein Binding; D040901:Proteomics
chemical_list: D008670:Metals