Up-Regulation of Insulin/Insulin-Like Growth Factor-I Hybrid Receptors during Differentiation of HT29-D4 Human Colonic Carcinoma Cells1
| Autor: | Gilbert Pommier, F Garrouste, Jacques Marvaldi, M Remacle-Bonnet, Maxime Lehmann |
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| Rok vydání: | 1997 |
| Předmět: | |
| Zdroj: | Endocrinology. 138:2021-2032 |
| ISSN: | 1945-7170 0013-7227 |
| Popis: | To assess the autocrine function of insulin-like growth factor II (IGF-II) in the balance of proliferation and differentiation in HT29-D4 human colonic cancer cells, we studied the expression of IGF-I receptors (IGF-IR) and insulin receptors (IR) in relation to the state of cell differentiation. IGF-IR and IR were expressed in both undifferentiated and enterocyte-like differentiated HT29-D4 cells. IGF-IR had two isoforms with a 97-kDa and a 102-kDa β-subunit. In addition, HT29-D4 cells expressed hybrid receptors (HR) formed by the association of two αβ heterodimers from both IR and IGF-IR. HR were evidenced through 1) inhibition of IGF-I binding by the B6 anti-IR antibody and 2) immunoprecipitation with the α-IR3 anti-IGF-IR antibody, which revealed an additional 95-kDa IR β-subunit that disappeared when the heterotetrameric receptor was dissociated by disulfide reduction into αβ heterodimers before immunoprecipitation. Like IGF-IR, HR had a high affinity for IGF-I (Kd, ∼1.5 nm), but did not bind insulin ... |
| Databáze: | OpenAIRE |
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