Modes of Calreticulin Recruitment to the Major Histocompatibility Complex Class I Assembly Pathway
| Autor: | Ericca Stamper, Chester J. Provoda, Larry Robert Peters, William Clay Brown, Elise Jeffery, Natasha Del Cid, Syed Monem Rizvi, Malini Raghavan |
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| Rok vydání: | 2010 |
| Předmět: |
CD74
Genetic Vectors Antigen presentation Protein Disulfide-Isomerases Biochemistry Cell Line Mice Structure-Activity Relationship Tapasin Polysaccharides MHC class I Animals Humans Immunoprecipitation Molecular Biology biology Antigen processing Histocompatibility Antigens Class I Cell Biology Transporter associated with antigen processing MHC restriction Flow Cytometry Molecular biology Protein Structure Tertiary Cell biology Protein Structure and Folding Chromatography Gel Mutagenesis Site-Directed biology.protein Calreticulin Protein Binding Signal Transduction |
| Zdroj: | Journal of Biological Chemistry. 285:4520-4535 |
| ISSN: | 0021-9258 |
| DOI: | 10.1074/jbc.m109.085407 |
| Popis: | Major histocompatibility complex (MHC) class I molecules are ligands for T-cell receptors of CD8(+) T cells and inhibitory receptors of natural killer cells. Assembly of the heavy chain, light chain, and peptide components of MHC class I molecules occurs in the endoplasmic reticulum (ER). Specific assembly factors and generic ER chaperones, collectively called the MHC class I peptide loading complex (PLC), are required for MHC class I assembly. Calreticulin has an important role within the PLC and induces MHC class I cell surface expression, but the interactions and mechanisms involved are incompletely understood. We show that interactions with the thiol oxidoreductase ERp57 and substrate glycans are important for the recruitment of calreticulin into the PLC and for its functional activities in MHC class I assembly. The glycan and ERp57 binding sites of calreticulin contribute directly or indirectly to complexes between calreticulin and the MHC class I assembly factor tapasin and are important for maintaining steady-state levels of both tapasin and MHC class I heavy chains. A number of destabilizing conditions and mutations induce generic polypeptide binding sites on calreticulin and contribute to calreticulin-mediated suppression of misfolded protein aggregation in vitro. We show that generic polypeptide binding sites per se are insufficient for stable recruitment of calreticulin to PLC substrates in cells. However, such binding sites could contribute to substrate stabilization in a step that follows the glycan and ERp57-dependent recruitment of calreticulin to the PLC. |
| Databáze: | OpenAIRE |
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