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ISOLATION AND CHARACTERIZATION OF A SOMATOMEDIN RECEPTOR FROM THE A1684 HUMAN CHONDROSARCOMA CELL LINE
Abstract
In studies aimed at understanding the mechanism of action of somatomedins on their target cells, a human chondrosarcoma cell line (A1684) was utilized to study the interaction of a somatomedin with its specific receptor. The somatomedin used for these studies was Multiplication-stimulating Activity (MSA), a rat somatomedin. This hormone is produced by a cloned buffalo rat liver cell line in serum-free culture and is readily purified from medium conditioned by this cell line. For these studies, the growth characteristics of the human chondrosarcoma cell line were analyzed. This cell line was capable of regulating its own growth as shown by the fact that upon incubation with increasing concentrations of calf serum, there was a corresponding increase in final saturation density and by the ability to reach a quiescent state upon incubation in the presence or absence of low concentrations of calf serum. While these cells showed no mitogenic response to MSA, MSA was capable of stimulating the transport of ('14)C-(alpha)-aminoisobutyric acid and ('3)H-2-deoxyglucose and the incorporation of ('35)S-sulfate into acid precipitable material in these cells. The somatomedin receptor present in A1684 cells exhibited an affinity constant for MSA of 7.52 x 10('7) M('-1) with a binding capacity of 1.9 x 10('6) receptors per cell. MSA binding was insensitive to competition with unlabeled insulin. The somatomedin receptor identified using chemical cross-linking, exhibited a molecular weight of 218,000 daltons under non-reducing conditions and 280,000 daltons under reducing conditions upon electrophoresis on SDS polyacrylamide gels. These characteristics describe a type II insulin-insensitive somatomedin receptor in the A1684 cell line. These studies help to lay the foundation for further studies to elucidate the biochemical and biological properties of the somatomedin receptor.
Subject Area
Biology
Recommended Citation
COOPER, JANET LEIGH, "ISOLATION AND CHARACTERIZATION OF A SOMATOMEDIN RECEPTOR FROM THE A1684 HUMAN CHONDROSARCOMA CELL LINE" (1984). ETD collection for University of Nebraska-Lincoln. AAI8423771.
https://digitalcommons.unl.edu/dissertations/AAI8423771