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.
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.
Mesh Terms:
Antiporters, Biological Transport, Cell Line, Coat Protein Complex I, Endoplasmic Reticulum, Golgi Apparatus, Histocompatibility Antigens Class I, Immunoglobulins, Membrane Transport Proteins, Subcellular Fractions
Antiporters, Biological Transport, Cell Line, Coat Protein Complex I, Endoplasmic Reticulum, Golgi Apparatus, Histocompatibility Antigens Class I, Immunoglobulins, Membrane Transport Proteins, Subcellular Fractions
J. Biol. Chem.
Date: May. 24, 2002
PubMed ID: 11884415
View in: Pubmed Google Scholar
Download Curated Data For This Publication
9931
Switch View:
- Interactions 12
