First Author | Paquet ME | Year | 2004 |
Journal | J Immunol | Volume | 172 |
Issue | 12 | Pages | 7548-55 |
PubMed ID | 15187134 | Mgi Jnum | J:90842 |
Mgi Id | MGI:3044858 | Doi | 10.4049/jimmunol.172.12.7548 |
Citation | Paquet ME, et al. (2004) Bap29/31 influences the intracellular traffic of MHC class I molecules. J Immunol 172(12):7548-55 |
abstractText | In this study, we examine the role of the putative cargo receptor B cell-associated protein (Bap)29/31 in the export of MHC class I molecules out of the endoplasmic reticulum (ER). We show that Bap31 binds to two allotypes of mouse class I molecules, with the interaction initiated at the time of H chain association with beta(2)-microglobulin and maintained until the class I molecule has left the ER. We also show that Bap31 is part of the peptide-loading complex, although is not required for its formation. Bap31 binds not only to class I molecules, but can bind to tapasin in the absence of class I. Consistent with an important role in recruiting class I molecules to transport vesicles, we show that in the absence of Bap29/31, there is a loss of class I colocalization with mSec31 (p137), a component of mammalian coat protein complex II coats. This observation is also associated with a delay in class I traffic from ER to Golgi. Our results are consistent with the view that class I molecules are largely recruited to ER exit sites by Bap29/31, and that Bap29/31 is a cargo receptor for MHC class I molecules. |