Edited by Masayuki Miyasaka
M. D. Max Crispin (a), (b), 1, Gayle E. Ritchie (a), 1, Alison J. Critchley (a), B. Paul Morgan (c), Ian A. Wilson (b), (d), Raymond A. Dwek (a), Robert B. Sim (e) and Pauline M. Rudd (a)
1 These authors contributed equally to this work.
FEBS Letters, 2004, 566: 270-274
Abstract
The monoglucosylated oligomannose N-linked oligosaccharide (Glc1Man9GlcNAc2) is a retention signal for the calnexin-calreticulin quality control pathway in the endoplasmic reticulum. We report here the presence of such monoglucosylated N-glycans on the human complement serum glycoprotein C3. This finding represents the first report of monoglucosylated glycans on a human serum glycoprotein from non-diseased individuals. The presence of the glucose moiety in 5% of the human C3 glycoprotein suggests that this glycosylation site is sequestered within the protein and is consistent with previous studies identifying a cryptic conglutinin binding site on C3 that becomes exposed upon its conversion to iC3b.
Author Keywords: Complement component C3; Glycosylation; Monoglucosylation; Calnexin; Calreticulin
Corresponding author. Fax: +44-1865-275216
(a) Department of Biochemistry, Oxford Glycobiology Institute, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
(b) Department of Molecular Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
(c) Department of Medical Biochemistry and Immunology, University of Wales College of Medicine, Health Park, Cardiff CF14 4XN, Wales, UK
(d) Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
(e) MRC Immunochemistry Unit, Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK | 
