Quantitative determination of the lateral diffusion coefficients of the hormone-receptor complexes of insulin and epidermal growth factor on the plasma membrane of cultured fibroblasts.

Abstract

Fluorescent derivatives of insulin and epidermal growth factor bound to 3T3 mouse fibroblasts are mobile on the cell surface, with similar diffusion coefficients, D .apprxeq. (3-5) .times. 10-10 cm2/s at 23.degree. C. Increasing the temperature to 37.degree. C results in rapid receptor immobilization. The immobilization is attributed to aggregation of hormone-receptor complexes, their internalization, or a combination of both processes.