Association of tapasin and COPI provides a mechanism for the retrograde transport of major histocompatibility complex (MHC) class I molecules from the Golgi complex to the endoplasmic reticulum

Research output: Contribution to journalArticle


Tapasin is a subunit of the transporter associated with antigen processing (TAP). It associates with the major histocompatibility complex (MHC) class I. We show that tapasin interacts with beta- and gamma-subunits of COPI coatomer. COPI retrieves membrane proteins from the Golgi network back to the endoplasmic reticulum (ER). The COPI subunit-associated tapasin also interacts with MHC class I molecules suggesting that tapasin acts as the cargo receptor for packing MHC class I molecules as cargo proteins into COPI-coated vesicles. In tapasin mutant cells, neither TAP nor MHC class I are detected in association with the COPI coatomer. Interestingly, tapasin-associated MHC class I molecules are antigenic peptide-receptive and detected in both the ER and the Golgi. Our data suggest that tapasin is required for the COPI vesicle-mediated retrograde transport of immature MHC class I molecules from the Golgi network to the ER.


External organisations
  • Lund University
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Cell and Molecular Biology


  • Non-U.S. Gov't, Subcellular Fractions/metabolism, Support, Histocompatibility Antigens Class I/*metabolism, Immunoglobulins/*metabolism, Golgi Apparatus/*metabolism, Endoplasmic Reticulum/*metabolism, Coat Protein Complex I/*metabolism, Cell Line, Antiporters/*metabolism, Biological Transport
Original languageEnglish
Pages (from-to)18266-18271
Number of pages6
JournalJournal of Biological Chemistry
Issue number21
Publication statusPublished - 2002 May 24
Publication categoryResearch