Microaggregation of hormone-occupied epidermal growth factor receptors on plasma membrane preparations.

摘要: The rotational diffusion of the complexes epidermal growth factor (EGF) with its specific receptor on plasma membrane vesicles prepared from human epidermoid carcinoma A431 cells was studied using time-resolved polarization phosphorescence erythrosin-labeled hormone. measured correlation times 16-20 microseconds at 4 degrees C are consistent monomeric freely diffusing EGF receptor. Upon increasing temperature to 37 C, rate slows down as evidenced by an increase in time 75 microseconds. This finding suggests that small clusters occupied (microaggregation) form higher temperature, a property we have reported previously for receptors living cells. Subsequent cooling membranes leads partial reversal microaggregation. We conclude clustering can proceed absence metabolic energy and external interactions, e.g. components cytoskeleton, thus reflects inherent properties protein natural environment. A lag phase course microaggregation observed isolated preparations may reflect cooperativity process association.