Association of EGF and LDL receptors with the cytoskeleton of cultured keratinocytes.

In this paper we demonstrate that isolated cytoskeletons of normal keratinocytes cultured under differentiation inducing conditions exhibit a high level of epidermal growth factor (EGF) binding. This binding is approximately 300% higher than the binding of intact cells. In contrast, various squamous carcinoma cell lines or normal keratinocytes cultured under differentiation retarding conditions exhibit EGF binding to isolated cytoskeletons which is around 10-20% of the binding to intact cells. Incubation of normal keratinocytes in the presence of arotinoid ethyl sulfone resulted in a marked decrease of the ability of the cells to differentiate, and a decrease of EGF binding to isolated cytoskeletons. These results suggest a close relationship between the differentiation capacity of the cells and the presence of cytoskeleton-associated EGF receptors. Similar results were obtained for low density lipoprotein (LDL) binding.