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- Title
ER-60, a chaperone with thiol-dependent reductase activity involved in MHC class I assembly.
- Authors
Lindquist, Jonathan A.; Jensen, Ole N.; Mann, Matthias; Hämmerling, Günter J.
- Abstract
The assembly of newly synthesized MHC class I molecules within the endoplasmic reticulum and their association with the transporter associated with antigen processing (TAP) is a process involving the chaperones calnexin and calreticulin. Using peptide mapping by matrix-assisted laser desorption/ionization (MALDI) mass spectrometry to identify a new component, we now introduce a third molecular chaperone, the thioldependent reductase ER-60 (ERp57/GRP58/ERp61/HIP-70/Q2), into this process. ER-60 is found in MHC class I heavy chain complexes with calnexin that are generated early during the MHC class I assembly pathway. The thiol reductase activity of ER-60 raises the possibility that ER-60 is involved in the disulfide bond formation within heavy chains. In addition, ER-60 is part of the late assembly complexes consisting of MHC class I, tapasin, TAP, calreticulin and calnexin. In a β2-microglobulin (β2m)-negative mouse cell line, S3, ER-60calnexinheavy chain complexes are shown to bind to TAP, suggesting that 2m is not required for the association of MHC class I heavy chains with TAP.
- Subjects
MOLECULAR chaperones; THIOLS; MAJOR histocompatibility complex; ANTIGEN presenting cells; IMMUNOCOMPETENT cells; PROTEINS; MASS spectrometry
- Publication
EMBO Journal, 1998, Vol 17, Issue 8, p2186
- ISSN
0261-4189
- Publication type
Article
- DOI
10.1093/emboj/17.8.2186