Mannose 6-phosphate/insulin-like growth factor II-binding proteins in human serum and urine. Their relation to the mannose 6-phosphate/insulin-like growth factor II receptor

• Published in: Biochemical journal 1988-06, Vol.252 (3), p.795-799
• Main Authors: Causin, C, Waheed, A, Braulke, T, Junghans, U, Maly, P, Humbel, R E, von Figura, K
• Format: Article
• Language: English
• Subjects: Carrier Proteins - blood; Carrier Proteins - immunology; Carrier Proteins - metabolism; Carrier Proteins - urine; Cross Reactions; Electrophoresis, Polyacrylamide Gel; Hexosephosphates - metabolism; Humans; IGF-II; Insulin-Like Growth Factor Binding Proteins; Insulin-Like Growth Factor II - metabolism; Lectins, C-Type; man; Mannose-Binding Lectins; Mannosephosphates - metabolism; Peptide Fragments - immunology; Receptor, Insulin - immunology; Receptor, Insulin - metabolism; Receptors, Cell Surface; Receptors, Immunologic - immunology; Receptors, Immunologic - metabolism; Receptors, Somatomedin; Somatomedins - metabolism
• ISSN: 0264-6021; 1470-8728
• DOI: 10.1042/bj2520795

Human serum and urine contain polypeptides which bind mannose 6-phosphate (M6P) and insulin-like growth factor II (IGF II) and crossreact with antibodies against the M6P/IGF II receptor. These polypeptides are considered to be fragments of the M6P/IGF II receptor. The major Mr approx. 205,000 fragment in serum and urine is about 10 kDa smaller in size than the membrane-associated receptor and is accompanied by minor forms with Mr values ranging from 104,000 to 180,000. The presence of receptor fragments in biological fluids indicates that shedding is one of the mechanisms contributing to the turnover of the M6P/IGF II receptor and that receptor fragments are part of the heterogenous group of serum proteins whic bind IGF II.