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- Title
Characterization of Receptors for Insulin-Like Growth Factors in Human Brain.
- Authors
Sasaki, N.; Nakamura, K.; Kubota, K.; Uchimura, H.
- Abstract
The structural properties of receptors for insulin-like growth factors (IGFs) in human brain were studied. Brain membranes were incubated with 125I-IGF-I or II, cross-linked with disuccinimidyl suberate and subjected to electrophoresis under reducing conditions and auto-radiography. Two proteins with apparent molecular weights of 120 and 220 kD were specifically labeled. The labeled proteins were immunoprecipitated with monoclonal antibody to type I IGF receptors, indicating that they represent α-subunit and its dimer of type I IGF receptor. The size of brain α-subunit was smaller than placental α-subunit (130 kD). Treatment with N-glycosidase F reduced the brain α-subunit from 120 to 95 kD and the placental α-subunit from 130 to 105 kD. Neuraminidase decreased the placental α-subunit from 130 to 125 kD, but it had no effect on the mobility of the brain α-subunit. Solubilized IGF-I receptors from placenta were retained by wheat germ agglutinin and concanavalin A columns, and eluted with the specific sugars. In contrast, solubilized IGF-I receptors from brain did not bind to these columns. These results indicate that human brains have only type I IGF receptors and that the molecular size of the α-subunit in brain receptors is smaller than in placental receptors. The size discrepancy may result from the differences in both protein and carbohydrate moieties. Copyright © 1991 S. Karger AG, Basel
- Publication
Gerontology, 1991, Vol 37, Issue S1, p3
- ISSN
0304-324X
- Publication type
Article
- DOI
10.1159/000213290