Cell-surface expression of H-2Db requires N-linked glycans.
The question of whether beta-2 microglobulin (B2m)-independent expression of the mouse major histocompatibility complex (MHC) antigen H-2Db results from the atypical glycosylation pattern associated with this MHC antigen (i.e., three glycans instead of two) has been addressed. Cell-surface expression of transfected H-2Db in the B2m deficient cell line R1E was completely abolished by the drug tunicamycin (Tm). Introduction of a functional B2m gene by transfection did not re-establish cell-surface expression of Db in the presence of Tm. Tm had no effect, however, on the expression of a truncated Db molecule lacking the alpha 1 and alpha 2 domains which is glycosylated at amino acid position 256, suggesting that the Db molecule, unlike other class I antigens, possesses an unstable conformation in the alpha 1 and/or alpha 2 domains which requires the attachment of glycans before it is transported to the cell surface. Once attached, however, glycans may confer a stable alpha 1/alpha 2 conformation apparently peculiar to Db which allows cell-surface expression in the absence of B2m.
Fraser
J D
JD
Allen
H
H
Flavell
R A
RA
Strominger
J L
JL
D000954:Antigens, Surface / Q000032:analysis*; D002460:Cell Line; D006031:Glycosylation; D006183:H-2 Antigens / Q000032:analysis*; D064532:Histocompatibility Antigen H-2D; D008970:Molecular Weight; D011134:Polysaccharides / Q000502:physiology*; D011487:Protein Conformation; D014415:Tunicamycin / Q000494:pharmacology; D001613:beta 2-Microglobulin / Q000235:genetics
D000954:Antigens, Surface; D006183:H-2 Antigens; D064532:Histocompatibility Antigen H-2D; D011134:Polysaccharides; D001613:beta 2-Microglobulin; D014415:Tunicamycin