Cell surface expression of C1qRP/CD93 is stabilized by O-glycosylation.
J Cell Physiol
; 196(3): 512-22, 2003 Sep.
Article
in En
| MEDLINE
| ID: mdl-12891708
ABSTRACT
C1qRP/CD93 is a cell surface receptor predominantly expressed on monocytes, neutrophils, endothelial cells, and early stem cell precursors. In phagocytic cells, it has been characterized as contributing to the enhancement of FcR- and CR1-induced phagocytosis triggered by innate immune system defense collagens such as C1q and mannose binding lectin (MBL). Previously, we demonstrated a high level of glycosylation on C1qRP/CD93 that was predominantly O-linked. In this study, we investigate the role of glycosylation in C1qRP/CD93 stability first by inhibiting O-glycosylation by addition of benzyl 2-acetamido-2-deoxy-alpha-D-galactopyranoside (BAG) to the human histiocytic cell line U937, and secondly, by expression of C1qRP/CD93 in the CHO-derived cell line ldlD which has a reversible defect in protein glycosylation. In both U937 cells and in ldlD cells transfected to express C1qRP/CD93, glycosylation deficiency caused cell surface expression levels of C1qRP/CD93 to decrease, concomitant with the detection of C1qRP/CD93 reactivity in the culture media. Metabolic labeling studies show that when glycosylation is absent, C1qRP/CD93 is synthesized and rapidly released into the culture supernatant or degraded. These studies demonstrate that O-glycosylation is important in the stable cell surface expression of C1qRP/CD93 .
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Collection:
01-internacional
Database:
MEDLINE
Main subject:
Membrane Glycoproteins
/
Receptors, Complement
/
Cell Membrane
/
Gene Expression Regulation
/
Hyaluronan Receptors
Limits:
Animals
/
Humans
Language:
En
Journal:
J Cell Physiol
Year:
2003
Document type:
Article
Affiliation country:
United States