Premium
Identification of an insulin‐like growth factor‐binding protein in human cerebrospinal fluid with a selective affinity for IGF‐II
Author(s) -
Hossenlopp Paul,
Seurin Danielle,
Segovia-Quinson Berta,
Binoux Michel
Publication year - 1986
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(86)81065-1
Subject(s) - chromatofocusing , isoelectric point , cerebrospinal fluid , isoelectric focusing , polyacrylamide gel electrophoresis , chemistry , gel electrophoresis , biochemistry , growth factor , biology , microbiology and biotechnology , receptor , neuroscience , enzyme
Human cerebrospinal fluid (CSF) has been found to contain several different molecular forms of IGF‐specific binding proteins (BPs). Qualitatively, they are similar to those present in serum, although their relative proportions are very different, as well as to those present in the culture media of brain tissue from which these BPs presumably arise. One particular form of BP is predominant in CSF. It has an M r of 34 000, as estimated by SDS‐polyacrylamide gel electrophoresis followed by transfer onto nitrocellulose, and an isoelectric point around 5.0 based on chromatofocusing. It has a selective affinity for IGF‐II (~4 × 10 10 M −1 ) as shown by competitive binding experiments in which biosynthetic IGF‐I was about 40‐times less potent than native IGF‐II in displacing 125 I‐labelled IGF‐II. These findings are in agreement with the preponderance of IGF‐II in nervous tissue and in CSF and suggest that this BP plays an important role in the interaction of IGF‐II with its target cells.