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Release from Endoplasmic Reticulum Matrix Proteins Controls Cell Surface Transport of MHC Class I Molecules
Author(s) -
Fritzsche Susanne,
Abualrous Esam T.,
Borchert Britta,
Momburg Frank,
Springer Sebastian
Publication year - 2015
Publication title -
traffic
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.677
H-Index - 130
eISSN - 1600-0854
pISSN - 1398-9219
DOI - 10.1111/tra.12279
Subject(s) - endoplasmic reticulum , biology , microbiology and biotechnology , mhc class i , transporter associated with antigen processing , matrix (chemical analysis) , cell , stim1 , transport protein , major histocompatibility complex , biochemistry , gene , materials science , composite material
The anterograde transport of secretory proteins from the endoplasmic reticulum ( ER ) to the plasma membrane is a multi‐step process. Secretory proteins differ greatly in their transport rates to the cell surface, but the contribution of each individual step to this difference is poorly understood. Transport rates may be determined by protein folding, chaperone association in the ER , access to ER exit sites ( ERES ) and retrieval from the ER ‐Golgi intermediate compartment or the cis ‐Golgi to the ER . We have used a combination of folding and trafficking assays to identify the differential step in the cell surface transport of two natural allotypes of the murine major histocompatibility complex ( MHC ) class I peptide receptor, H‐ 2D b and H‐ 2K b . We find that a novel pre‐ ER exit process that acts on the folded lumenal part of MHC class I molecules and that drastically limits their access to ERES accounts for the transport difference of the two allotypes. Our observations support a model in which the cell surface transport of MHC class I molecules and other type I transmembrane proteins is governed by the affinity of all their folding and maturation states to the proteins of the ER matrix.