N-glycan-mediated quality control in the endoplasmic reticulum is required for the expression of correctly folded delta-opioid receptors at the cell surface.

ABSTRACT: A great majority of G protein-coupled receptors are modified by N-glycosylation, but the functional significance of this modification for receptor folding and intracellular transport has remained elusive. Here we studied these phenomena by mutating the two N-terminal N-glycosylation sites (Asn(18) and Asn(33)) of the human delta-opioid receptor, and expressing the mutants from the same chromosomal integration site in stably transfected inducible HEK293 cells. Both N-glycosylation sites were used, and their abolishment decreased the steady-state level of receptors at the cell surface. However, pulse-chase labeling, cell surface biotinylation, and immunofluorescence microscopy revealed that this was not because of intracellular accumulation. Instead, the non-N-glycosylated receptors were exp

SUBMITTER: Markkanen PM 

PROVIDER: S-EPMC2662010 | biostudies-literature | 2008 Oct

REPOSITORIES: biostudies-literature