Tapasin and other chaperones: Models of the MHC class I loading complex

Cynthia Anne Wright, Patrycja Kozik, Martin Zacharias, Sebastian Springer

Research output: Contribution to journalReview articlepeer-review

71 Scopus citations


MHC (major histocompatibility complex) class I molecules bind intracellular virus-derived peptides in the endoplasmic reticulum (ER) and present them at the cell surface to cytotoxic T lymphocytes. Peptide-free class I molecules at the cell surface, however, could lead to aberrant T cell killing. Therefore, cells ensure that class I molecules bind high-affinity ligand peptides in the ER, and restrict the export of empty class I molecules to the Golgi apparatus. For both of these safeguard mechanisms, the MHC class I loading complex (which consists of the peptide transporter TAP, the chaperones tapasin and calreticulin, and the protein disulfide isomerase ERp57) plays a central role. This article reviews the actions of accessory proteins in the biogenesis of class I molecules, specifically the functions of the loading complex in high-affinity peptide binding and localization of class I molecules, and the known connections between these two regulatory mechanisms. It introduces new models for the mode of action of tapasin, the role of the class I loading complex in peptide editing, and the intracellular localization of class I molecules.

Original languageEnglish
Pages (from-to)763-778
Number of pages16
JournalBiological Chemistry
Issue number9
StatePublished - Sep 2004
Externally publishedYes


  • Calreticulin
  • ERp27
  • Major histocompatibility complex molecules
  • Peptide binding
  • TAP
  • Tapasin


Dive into the research topics of 'Tapasin and other chaperones: Models of the MHC class I loading complex'. Together they form a unique fingerprint.

Cite this