Direct linkage of epidermal growth factor to its receptor

Identification of the EGF receptor on 3T3 cells by surface‐specific iodination and gel electrophoresis

“…fetal calf serum; DME, Dulhecco's modified Eagle's medhzm; Hepes, 4-('&hydrox~-e~yl)-l-pipe~~ee~~e~o~c acid; BSA, bovin serum albumin; SDS, sodium dodecyl sulfate EIsevier/North-Holland Biomedical Press iodinated cells was possible only when trypsin treatment was used to amplify the radioactivity present in receptor protein relative to other proteins. The molecular weight of the radioiodinated receptor protein is in good agreement with the value for the EGF-receptor complex formed by photoaffmity labeling [6] and that of the apparently covalent ['251]EGF-receptor 'direct-labeled' complex which forms in low yield when cells are ~cubated with f'251]EGF [16]. We also report that binding of EGF to its receptor may alter the site at which the recep tor is cleaved by protease.…”

“…Previous approaches to identification of receptors for epidermal growth factor have relied on the linkage of ['*'I]EGF to receptor [6,13,16]. These experiments revealed a small portion (1%) of the specifically bound ['*'I] EGF covalently attached to a single high molecular weight radioactive receptor band.…”

Hormone receptor topology and dynamics: Morphological analysis using ferritin-labeled epidermal growth factor

“…Biochemical evidence that hormone binding capacity decreases after hormonal stimulation (down-regulation) suggests that receptors may be removed from the cell surface or modified to decrease binding capacity (4-7); however, the resolution of experimental techniques has been insufficient to differentiate clearly between these alternatives. Attempts to covalently link 125I-labeled EGF to its putative membrane receptor and follow its metabolic fate have been reported (8)(9)(10). The results suggest receptor internalization; however, only a small fraction of the membrane-bound EGF was successfully crosslinked, and many questions remain concerning the membrane sites, stability, and mode of down-regulation for the majority of EGF receptors.…”

Interactions of High Affinity Insulin-like Growth Factor-binding Proteins with the Type V Transforming Growth Factor-β Receptor in Mink Lung Epithelial Cells

“…This experiment was performed in the presence of the cross-linking agent DSS. Because 125 I-labeled proteins prepared by the chloramine-T procedure are known to acquire the properties of covalent linking during 125 I-labeling (27)(28)(29), the covalently linked dimers of 125 I-IGFBPs may be spontaneously produced in a DSS-independent manner during the incubation (3 h at 0°C) of cells with 125 I-IGFBPs that were also prepared These results indicate that the formation of the covalently linked 125 I-IGFBP-3 dimer does not require the presence of crosslinking agents. These results also suggest that the 125 I-IGFBP-3 dimer formation may be enhanced at the cell surface.…”