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rdf:type |
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lifeskim:mentions |
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pubmed:issue |
2
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pubmed:dateCreated |
1988-10-21
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pubmed:abstractText |
This study was conducted to determine how extraordinarily high numbers of epidermal growth factor receptors (EGF-R) affected the binding and internalization of EGF in the transformed cell line A431. I found that at low EGF concentrations, the kinetics of binding behaved as a nonsaturable, first-order process showing no evidence of multiple-affinity classes of receptors. However, EGF dissociation rates were strongly dependent on the degree of receptor occupancy in both intact cells and isolated membranes. This occupancy-dependent dissociation appears to be due to diffusion-limited binding. EGF-induced receptor internalization was rapid and first order when the absolute number of occupied receptors was below 4 x 10(3) min-1. However, at higher occupancies the specific internalization rate progressively declined to a final limiting value of 20% normal. The saturation of EGF-R endocytosis was specific since internalization of transferrin receptors was not affected by high concentrations of either transferrin or EGF. Saturation of EGF-R endocytosis probably involves a specific component of the endocytic pathway since fluid phase endocytosis increased coordinately with EGF-R occupancy. I conclude that there are several aspects of EGF-R dynamics on A431 cells are neither similar to the behavior of EGF-R in other cell types nor similar to the reported behavior of other hormone receptors. Although A431 cells have an extraordinary number of EGF-R, they do not seem to have corresponding levels of at least two other crucial cell surface components: one that mediates EGF-induced rapid receptor internalization and one that attenuates EGF-induced membrane responses. These factors, in addition to the presence of diffusion-limited binding at low EGF concentrations, are probably responsible for the appearance of multiple-affinity classes of receptors in this cell type.
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pubmed:grant |
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pubmed:commentsCorrections |
http://linkedlifedata.com/resource/pubmed/commentcorrection/3262110-230489,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3262110-2960385,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3262110-3011821,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3262110-3015587,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3262110-3031062,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3262110-3031063,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3262110-3032981,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3262110-306388,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3262110-313931,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3262110-315944,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3262110-3316935,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3262110-356052,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3262110-4636326,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3262110-6090128,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3262110-6092175,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3262110-6094567,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3262110-6095297,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3262110-6128346,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3262110-6149699,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3262110-6149810,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3262110-6153980,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3262110-6190668,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3262110-6196602,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3262110-6202705,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3262110-6220739,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3262110-6246084,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3262110-6253485,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3262110-6259181,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3262110-6260020,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3262110-6268987,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3262110-6269748,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3262110-6272837,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3262110-6273899,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3262110-6276390,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3262110-6279628,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3262110-6282315,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3262110-6286649,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3262110-6288686,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3262110-6298257,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3262110-6298788,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3262110-6325444,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3262110-6326261,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3262110-6328312,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3262110-6498281,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3262110-6946494,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3262110-7040412,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3262110-786865,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3262110-911982,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3262110-944704,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3262110-977646
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pubmed:language |
eng
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pubmed:journal |
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pubmed:citationSubset |
IM
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pubmed:chemical |
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pubmed:status |
MEDLINE
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pubmed:month |
Aug
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pubmed:issn |
0021-9525
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pubmed:author |
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pubmed:issnType |
Print
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pubmed:volume |
107
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
801-10
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pubmed:dateRevised |
2009-11-19
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pubmed:meshHeading |
pubmed-meshheading:3262110-Cell Line,
pubmed-meshheading:3262110-Cell Membrane,
pubmed-meshheading:3262110-Diffusion,
pubmed-meshheading:3262110-Endocytosis,
pubmed-meshheading:3262110-Epidermal Growth Factor,
pubmed-meshheading:3262110-Fibroblasts,
pubmed-meshheading:3262110-Humans,
pubmed-meshheading:3262110-Kinetics,
pubmed-meshheading:3262110-Ligands,
pubmed-meshheading:3262110-Receptor, Epidermal Growth Factor
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pubmed:year |
1988
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pubmed:articleTitle |
Anomalous binding of epidermal growth factor to A431 cells is due to the effect of high receptor densities and a saturable endocytic system.
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pubmed:affiliation |
Department of Pathology, University of Utah, Salt Lake City 84132.
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pubmed:publicationType |
Journal Article,
Research Support, U.S. Gov't, P.H.S.
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