[PDF][PDF] Roles for calreticulin and a novel glycoprotein, tapasin, in the interaction of MHC class I molecules with TAP
B Sadasivan, PJ Lehner, B Ortmann, T Spies… - Immunity, 1996 - cell.com
B Sadasivan, PJ Lehner, B Ortmann, T Spies, P Cresswell
Immunity, 1996•cell.comAssembly of MHC class I–β 2 microglobulin (β 2 m) dimers in the endoplasmic reticulum
involves two chaperones. Calnexin has previously been shown to interact with free class I
heavy chains. Here, we show that the related chaperone, calreticulin, binds human class I–β
2 m dimers prior to peptide loading. Calreticulin remains associated with at least a subset of
class I molecules when they, in turn, bind to TAP. Further evidence suggests that the
interaction of class I–β 2 m dimers with TAP occurs via a novel uncharacterized 48 kDa …
involves two chaperones. Calnexin has previously been shown to interact with free class I
heavy chains. Here, we show that the related chaperone, calreticulin, binds human class I–β
2 m dimers prior to peptide loading. Calreticulin remains associated with at least a subset of
class I molecules when they, in turn, bind to TAP. Further evidence suggests that the
interaction of class I–β 2 m dimers with TAP occurs via a novel uncharacterized 48 kDa …
Abstract
Assembly of MHC class I–β2 microglobulin (β2m) dimers in the endoplasmic reticulum involves two chaperones. Calnexin has previously been shown to interact with free class I heavy chains. Here, we show that the related chaperone, calreticulin, binds human class I–β2m dimers prior to peptide loading. Calreticulin remains associated with at least a subset of class I molecules when they, in turn, bind to TAP. Further evidence suggests that the interaction of class I–β2m dimers with TAP occurs via a novel uncharacterized 48 kDa glycoprotein, tapasin, which can bind independently to TAP and class I–β2m–calreticulin complexes. Tapasin is absent from the mutant cell line .220, in which class I–TAP association and peptide loading is defective.
cell.com
