title: Rotational mobility of high-affinity epidermal growth factor receptors on the surface of living A431 cells.
abstract: The rotational diffusion of epidermal growth factor (EGF) bound to its specific receptor on the surface of human carcinoma A431 cells was studied by means of time-resolved phosphorescence anisotropy measurements. The rotational mobility was measured on the total population of EGF receptors by using a saturating concentration of EGF conjugated with a phosphorescent label, erythrosin, or on the subpopulation of high-affinity EGF receptors by using a low concentration of labeled EGF. At 4 degrees C, the rotational correlation times for both the high-affinity and total (mostly low affinity) receptor populations were in the range of 60-100 microns. Elevation of the temperature to 37 degrees C resulted in a lengthening of the rotational correlation time of the total receptor population to 200-300 microns, confirming a previous study of receptor microaggregation. The high-affinity EGF receptors were completely immobilized at 37 degrees C (rotational correlation time greater than 500 microns). The data are consistent with a model involving association of the cytoskeleton with the high-affinity receptors at 37 degrees C, but not at 4 degrees C.
authors.affiliation: Department of Biology, University of California, Riverside 92521.
authors.forename: R
authors.initials: R
authors.lastname: Zidovetzki
authors.forename: D A
authors.initials: DA
authors.lastname: Johnson
authors.forename: D J
authors.initials: DJ
authors.lastname: Arndt-Jovin
authors.forename: T M
authors.initials: TM
authors.lastname: Jovin
mesh_terms: D000818:Animals; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism*; D004058:Diffusion; D004815:Epidermal Growth Factor / Q000378:metabolism; D066246:ErbB Receptors / Q000378:metabolism*; D004923:Erythrosine / Q000378:metabolism; D005454:Fluorescence Polarization; D006801:Humans; D011940:Receptor Aggregation; D013696:Temperature; D014407:Tumor Cells, Cultured
chemical_list: D004815:Epidermal Growth Factor; D066246:ErbB Receptors; D004923:Erythrosine