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The optimization of peptide cargo bound to MHC class I molecules by the peptide-loading complex

Record type: Article

Major histocompatibility complex (MHC) class I complexes present peptides from both self and foreign intracellular proteins on the surface of most nucleated cells. The assembled heterotrimeric complexes consist of a polymorphic glycosylated heavy chain, non-polymorphic ?2 microglobulin, and a peptide of typically nine amino acids in length. Assembly of the class I complexes occurs in the endoplasmic reticulum and is assisted by a number of chaperone molecules. A multimolecular unit termed the peptide-loading complex (PLC) is integral to this process. The PLC contains a peptide transporter (transporter associated with antigen processing), a thiooxido-reductase (ERp57), a glycoprotein chaperone (calreticulin), and tapasin, a class I-specific chaperone. We suggest that class I assembly involves a process of optimization where the peptide cargo of the complex is edited by the PLC. Furthermore, this selective peptide loading is biased toward peptides that have a longer off-rate from the assembled complex. We suggest that tapasin is the key chaperone that directs this action of the PLC with secondary contributions from calreticulin and possibly ERp57. We provide a framework model for how this may operate at the molecular level and draw parallels with the proposed mechanism of action of human leukocyte antigen-DM for MHC class II complex optimization.

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Elliott, T. and Williams, A. (2005) The optimization of peptide cargo bound to MHC class I molecules by the peptide-loading complex Immunological Reviews, 207, pp. 89-99. (doi:10.1111/j.0105-2896.2005.00311.x).

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Published date: 2005


Local EPrints ID: 26291
ISSN: 0105-2896
PURE UUID: ddc34e79-9f1f-4fcb-a678-1e56c69aa6e9
ORCID for T. Elliott: ORCID iD

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Date deposited: 19 Apr 2006
Last modified: 17 Jul 2017 16:07

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