O-glycosylation is essential for cell surface expression of the transcobalamin receptor CD320.

ABSTRACT: CD320 is a cell surface receptor that mediates vitamin B₁₂ uptake in most tissues. To date, the mechanisms that regulate CD320 expression on the cell surface are not fully understood. In this work, we studied CD320 expression in transfected human embryonic kidney (HEK) 293 and hepatoma HepG2 cells. By glycosidase and trypsin digestion, monensin and brefeldin treatment, western blotting, flow cytometry, and lectin binding, we found that CD320 underwent N- and O-glycosylation and sialylation, resulting in a ∼70-kDa band that formed a high-molecular-weight complex on the cell surface. Site-directed mutagenesis altering Asn126, Asn195, and Asn213 residues, individually or together, abolished N-glycosylation in CD320 but did not block its intracellular trafficking and expression on t

SUBMITTER: Du C 

PROVIDER: S-EPMC11667166 | biostudies-literature | 2024 Nov

REPOSITORIES: biostudies-literature