Differential control of cellular gene expression by diffusible and non-diffusible EGF

Cell gene expression is affected by both the kind and mode of growth factor stimulation (diffusive vs. non-diffusive). Epidermal growth factor (EGF) was pattern-immobilized on a polystyrene plate. Although the growth of the rat phaeochromocytoma cell line PC12 is stimulated by diffusible EGF, and differentiation is stimulated by diffusible nerve growth factor (NGF), immobilized (non-diffusible) EGF stimulated PC12 differentiation. The immobilized EGF caused a long-lasting stimulation of the intracellular signal protein mitogen-associated protein MAP kinase (MAPK, also known as ERK) and p38 (a subfamily of the MAPK superfamily) in cells, as did diffusible NGF. The switching between growth stimulation and differentiation is considered to be due to the duration of the stimulus. The function of the biosignal conjugate was regulated using conjugation methodology.