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Characterization of an Insulin Receptor in Human Y79 Retinoblastoma Cells
Author(s) -
Yorek Mark A.,
Spector Arthur A.,
Ginsberg Barry H.
Publication year - 1985
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1985.tb07231.x
Subject(s) - retinoblastoma , insulin , insulin receptor , cell culture , cell , receptor , cooperative binding , in vitro , cooperativity , endocrinology , medicine , retina , human insulin , chemistry , binding site , biology , biochemistry , insulin resistance , genetics , neuroscience , gene
Cultured human Y79 retinoblastoma cells bind [ 125 I]iodoinsulin in a manner similar to that of other CNS and peripheral tissues. The only difference noted between the insulin binding properties of the Y79 cells and other CNS preparations is that insulin binding to Y79 cells is down‐regulated by prolonged exposure of the cells to insulin. By contrast, studies with the various brain preparations indicate that the brain insulin receptor is not down‐regulated by circulating levels of insulin. Insulin binding to Y79 cells exhibits negative cooperativity, has a pH optimum of 7.8, is responsive to cations, and gives a curvilinear Scatchard plot. Y79 cell insulin binding capacity is 26 fmol/100 μg of cell protein, corresponding to about 125,000 binding sites per cell. These findings are the first to report insulin binding in a human cell line of retinal origin. The characterization of the insulin binding in this cell line may facilitate an understanding of the relationship between insulin and its specific functions in the human retina.