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High affinity epidermal growth factor receptors on the surface of A431 cells have restricted lateral diffusion.
Author(s) -
Rees A.R.,
Gregoriou M.,
Johnson P.,
Garland P.B.
Publication year - 1984
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1002/j.1460-2075.1984.tb02057.x
Subject(s) - epidermal growth factor , receptor , fluorescence recovery after photobleaching , a431 cells , biology , photobleaching , biophysics , microbiology and biotechnology , biochemistry , cell , fluorescence , physics , cell cycle , optics , membrane , molecular medicine
Rhodamine‐labelled epidermal growth factor (Rh‐EGF) was shown to bind to A431 cells grown at low density both to a small number of high affinity receptors (KD = 2.8 X 10(‐10) M; fraction of total binding sites approximately 0.12) and also to a large number of low affinity receptors (KD = 4 X 10(‐9) M; fraction of total binding sites approximately 0.88). Measurements of the lateral diffusion of EGF receptors on the cell surface were made using Rh‐EGF and the technique of fluorescence photobleaching recovery. The high affinity receptors (labelled with 1.6 X 10(‐10) M Rh‐EGF, 5% of EGF binding sites occupied) did not show lateral mobility over the temperature range 3 degrees‐37 degrees C. The low affinity receptors (labelled with 2.4 X 10(‐7) M Rh‐EGF, 90% of EGF sites occupied) showed at least 75% fluorescence recovery after photobleaching, and lateral diffusion coefficients of approximately 2 X 10(‐10) cm2/s. These results show that the two populations of EGF receptors defined by binding studies differ in their freedom to diffuse laterally. The observation that the high affinity receptors are immobile indicates that lateral diffusion of receptors, at least over a distance of a few hundred nanometres or more, may not be required for the action of low concentrations of EGF.