The luminal part of the murine cytomegalovirus glycoprotein gp40 catalyzes the retention of MHC class I molecules.
Murine cytomegalovirus (MCMV) interferes with the MHC class I pathway of antigen presentation. The type I transmembrane glycoprotein gp40, encoded by the gene m152, retains major histocompatibility complex (MHC) class I complexes in the endoplasmic reticulum (ER)-Golgi intermediate compartment (ERGIC)/cis-Golgi. These MHC class I complexes are stable, show an extended half-life and do not exchange beta(2)-microglobulin, whereas gp40 reaches an endosomal/lysosomal compartment where it subsequently is degraded. The analysis of regions within the viral protein that are essential for MHC class I retention revealed that a secreted form of gp40, lacking the cytoplasmic tail and the transmembrane region, still has the capacity to retain MHC class I complexes. Continuous expression of gp40 is not required for MHC class I retention. Our data indicate that the retention of MHC class I complexes in the ERGIC/cis-Golgi is triggered by gp40 and does not require the further presence of the viral protein.
Ziegler
H
H
Max-von-Pettenkofer Institut, Genzentrum, Ludwig-Maximilians-Universität München, Germany.
Muranyi
W
W
Burgert
H G
HG
Kremmer
E
E
Koszinowski
U H
UH
D016475:3T3 Cells; D000818:Animals; D017951:Antigen Presentation; D006566:Herpesviridae Infections / Q000276:immunology*; D008285:Major Histocompatibility Complex / Q000276:immunology*; D008562:Membrane Glycoproteins / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D051379:Mice; D018146:Muromegalovirus / Q000276:immunology*; D009154:Mutation; D012191:Retroviridae Proteins / Q000737:chemistry / Q000235:genetics / Q000276:immunology*
D008562:Membrane Glycoproteins; D012191:Retroviridae Proteins; C082614:SIV envelope protein gp41